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Effects of Nutrient Level and Growth Rate on the Conjugation Process That Transfers Mobile Antibiotic Resistance Genes in Continuous Cultures. Appl Environ Microbiol 2022; 88:e0112122. [PMID: 36094214 PMCID: PMC9552606 DOI: 10.1128/aem.01121-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria in the effluent of wastewater treatment plants (WWTPs) can transfer antibiotic resistance genes (ARGs) to the bacteria in receiving water through conjugation; however, there is a lack of quantitative assessment of this phenomenon in continuous cultures. Our objective was to determine the effects of background nutrient levels in river water column and growth rates of bacteria on the conjugation frequency of ARGs from effluent bacteria to river bacteria, as well as on the resulting resistance level (i.e., MICs) of the river bacteria. Chemostats were employed to simulate the discharge points of WWTPs into rivers, where effluent bacteria (donor cells) meet river bacteria (recipient cells). Both donor and recipient cells were Escherichia coli cells, and the donor cells were constructed by filter mating with bacteria in the effluent of a local WWTP. Results showed that higher bacterial growth rate (0.45 h-1 versus 0.15 h-1) led to higher conjugation frequencies (10-4 versus 10-6 transconjugant per recipient). The nutrient level also significantly affected the conjugation frequency, albeit to a lesser extent than the growth rate. The MIC against tetracycline increased from 2 mg/L in the recipient to 64 to 128 mg/L in transconjugants. In comparison, the MIC only increased to as high as 8 mg/L in mutants. Whole-genome sequencing showed that the tet-containing plasmid in both the donor and the transconjugant cells also occur in other fecal bacterial genera. The quantitative information obtained from this study can inform hazard identification related to the proliferation of wastewater-associated ARGs in surface water. IMPORTANCE WWTPs have been regarded as an important hot spot of ARGs. The discharge point of WWTP effluent, where ARGs may be horizontally transferred from bacteria of treated wastewater to bacteria of receiving water, is an important interface between the human-dominated ecosystem and the natural environment. The use of batch cultures in previous studies cannot adequately simulate the nutrient conditions and growth rates in receiving water. In this study, chemostats were employed to simulate the continuous growth of bacteria in receiving water. Furthermore, the experimental setup allowed for separate investigations on the effects of nutrient levels (i.e., simulating background nutrients in river water) and bacterial growth rates on conjugation frequencies and resulting resistance levels. The study generates statistically sound ecological data that can be used to estimate the risk of wastewater-originated ARGs as part of the One Health framework.
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Jung J, Jin H, Seo S, Jeong M, Kim B, Ryu K, Oh K. Short Communication: Enterotoxin Genes and Antibiotic Susceptibility of Bacillus cereus Isolated from Garlic Chives and Agricultural Environment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:12159. [PMID: 36231461 PMCID: PMC9564537 DOI: 10.3390/ijerph191912159] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/17/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
This study aims to investigate the enterotoxin profiles and antibiotic susceptibility of Bacillus cereus isolated from garlic chives and environmental samples. A total of 103 B. cereus isolates were used to identify enterotoxin genes, including hblA, hblC, hblD, nheA, nheB, and nheC. The hemolysin BL enterotoxin complex (hblACD) was detected in 38 isolates (36.9%), and the non-hemolytic enterotoxin complex (nheABC) was detected in 8 (7.8%) isolates. Forty-five isolates (43.7%) had hblACD and nheABC genes. B. cereus was resistant to β-lactam antibiotics and susceptible to non-β-lactam antibiotics. However, some B. cereus strains showed intermediate resistance to β-lactam and non-β-lactam antibiotics. B. cereus isolated from garlic chives showed intermediate resistance to cefotaxime (7.7%), rifampin (15.4%), clindamycin (30.8%), erythromycin (7.7%), and tetracycline (7.7%). B. cereus isolates from the agricultural environment were moderately resistant to cefotaxime (18.9%), rifampin (15.6%), clindamycin (12.2%), erythromycin (4.4%), and tetracycline (5.6%). Moreover, B. cereus isolates from garlic chives and cultivation environments could change their antibiotic resistance profile from susceptible to intermediate-resistant to rifampin, clindamycin, erythromycin, and tetracycline and exhibit multidrug resistance. These results indicate that continuous monitoring of B. cereus contamination in the produce and agricultural environment might be needed to ensure the safety of consuming fresh vegetables.
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Affiliation(s)
- Jieun Jung
- Functional Food Division, Department of Agro-Food Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Jeolloabuk-do, Korea
| | - Hyeonsuk Jin
- Microbial Safety Division, Department of Agro-food Safety and Crop Protection, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Jeollabuk-do, Korea
| | - Seungmi Seo
- Microbial Safety Division, Department of Agro-food Safety and Crop Protection, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Jeollabuk-do, Korea
| | - Myeongin Jeong
- Microbial Safety Division, Department of Agro-food Safety and Crop Protection, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Jeollabuk-do, Korea
| | - Boeun Kim
- Microbial Safety Division, Department of Agro-food Safety and Crop Protection, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Jeollabuk-do, Korea
| | - Kyoungyul Ryu
- Microbial Safety Division, Department of Agro-food Safety and Crop Protection, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Jeollabuk-do, Korea
| | - Kwangkyo Oh
- Microbial Safety Division, Department of Agro-food Safety and Crop Protection, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Jeollabuk-do, Korea
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Sheikh BA, Bhat BA, Mir MA. Antimicrobial resistance: new insights and therapeutic implications. Appl Microbiol Biotechnol 2022; 106:6427-6440. [PMID: 36121484 DOI: 10.1007/s00253-022-12175-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 11/29/2022]
Abstract
Antimicrobial resistance has not been a new phenomenon. Still, the number of resistant organisms, the geographic areas affected by emerging drug resistance, and the magnitude of resistance in a single organism are enormous and mounting. Disease and disease-causing agents formerly thought to be contained by antibiotics are now returning in new forms resistant to existing therapies. Antimicrobial resistance is one of the most severe and complicated health issues globally, driven by interrelated dynamics in humans, animals, and environmental health sectors. Coupled with various epidemiological factors and a limited pipeline for new antimicrobials, all these misappropriations allow the transmission of drug-resistant organisms. The problem is likely to worsen soon. Antimicrobial resistance in general and antibiotic resistance in particular is a shared global problem. Actions taken by any single country can adversely or positively affect the other country. Targeted coordination and prevention strategies are critical in stopping the spread of antibiotic-resistant organisms and hence its overall management. This article has provided in-depth knowledge about various methods that can help mitigate the emergence and spread of antimicrobial resistance globally. KEY POINTS: • Overview of antimicrobial resistance as a global challenge and explain various reasons for its rapid progression. • Brief about the intrinsic and acquired resistance to antimicrobials and development of antibiotic resistance in bacteria. • Systematically organized information is provided on different strategies for tackling antimicrobial resistance for the welfare of human health.
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Affiliation(s)
- Bashir Ahmad Sheikh
- Department of Bioresources, School of Biological Sciences, University of Kashmir, Srinagar, 190006, J&K, India
| | - Basharat Ahmad Bhat
- Department of Bioresources, School of Biological Sciences, University of Kashmir, Srinagar, 190006, J&K, India
| | - Manzoor Ahmad Mir
- Department of Bioresources, School of Biological Sciences, University of Kashmir, Srinagar, 190006, J&K, India.
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Gene Networks and Pathways Involved in Escherichia coli Response to Multiple Stressors. Microorganisms 2022; 10:microorganisms10091793. [PMID: 36144394 PMCID: PMC9501238 DOI: 10.3390/microorganisms10091793] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/19/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
Stress response helps microorganisms survive extreme environmental conditions and host immunity, making them more virulent or drug resistant. Although both reductionist approaches investigating specific genes and systems approaches analyzing individual stress conditions are being used, less is known about gene networks involved in multiple stress responses. Here, using a systems biology approach, we mined hundreds of transcriptomic data sets for key genes and pathways involved in the tolerance of the model microorganism Escherichia coli to multiple stressors. Specifically, we investigated the E. coli K-12 MG1655 transcriptome under five stresses: heat, cold, oxidative stress, nitrosative stress, and antibiotic treatment. Overlaps of transcriptional changes between studies of each stress factor and between different stressors were determined: energy-requiring metabolic pathways, transport, and motility are typically downregulated to conserve energy, while genes related to survival, bona fide stress response, biofilm formation, and DNA repair are mainly upregulated. The transcription of 15 genes with uncharacterized functions is higher in response to multiple stressors, which suggests they may play pivotal roles in stress response. In conclusion, using rank normalization of transcriptomic data, we identified a set of E. coli stress response genes and pathways, which could be potential targets to overcome antibiotic tolerance or multidrug resistance.
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Sabatino R, Sbaffi T, Corno G, de Carvalho DS, Trovatti Uetanabaro AP, Góes-Neto A, Podolich O, Kozyrovska N, de Vera JP, Azevedo V, Barh D, Di Cesare A. Metagenome Analysis Reveals a Response of the Antibiotic Resistome to Mars-like Extraterrestrial Conditions. ASTROBIOLOGY 2022; 22:1072-1080. [PMID: 35714354 PMCID: PMC9508453 DOI: 10.1089/ast.2021.0176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 04/07/2022] [Indexed: 06/15/2023]
Abstract
The spread of antibiotic resistance is becoming a serious global health concern. Numerous studies have been done to investigate the dynamics of antibiotic resistance genes (ARGs) in both indoor and outdoor environments. Nonetheless, few studies are available about the dynamics of the antibiotic resistome (total content of ARGs in the microbial cultures or communities) under stress in outer space environments. In this study, we aimed to experimentally investigate the dynamics of ARGs and metal resistance genes (MRGs) in Kombucha Mutualistic Community (KMC) samples exposed to Mars-like conditions simulated during the BIOMEX experiment outside the International Space Station with analysis of the metagenomics data previously produced. Thus, we compared them with those of the respective non-exposed KMC samples. The antibiotic resistome responded to the Mars-like conditions by enriching its diversity with ARGs after exposure, which were not found in non-exposed samples (i.e., tet and van genes against tetracycline and vancomycin, respectively). Furthermore, ARGs and MRGs were correlated; therefore, their co-selection could be assumed as a mechanism for maintaining antibiotic resistance in Mars-like environments. Overall, these results highlight the high plasticity of the antibiotic resistome in response to extraterrestrial conditions and in the absence of anthropogenic stresses.
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Affiliation(s)
- Raffaella Sabatino
- Water Research Institute (IRSA) - MEG Molecular Ecology Group, CNR - National Research Council of Italy, Verbania, Italy
| | - Tomasa Sbaffi
- Water Research Institute (IRSA) - MEG Molecular Ecology Group, CNR - National Research Council of Italy, Verbania, Italy
| | - Gianluca Corno
- Water Research Institute (IRSA) - MEG Molecular Ecology Group, CNR - National Research Council of Italy, Verbania, Italy
| | - Daniel Santana de Carvalho
- Laboratório de Biologia Molecular e Computacional de Fungos, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ana Paula Trovatti Uetanabaro
- Laboratório de Microbiologia Aplicada, Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus, Brasil
| | - Aristóteles Góes-Neto
- Laboratório de Biologia Molecular e Computacional de Fungos, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Olga Podolich
- Institute of Molecular Biology and Genetics of NASU, Kyiv, Ukraine
| | | | - Jean-Pierre de Vera
- German Aerospace Center (DLR), Space Operations and Astronaut Training, Microgravity User Support Center (MUSC), Cologne, Germany
| | - Vasco Azevedo
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Debmalya Barh
- Laboratório de Genética Celular e Molecular, Departamento de Genetica, Ecologia e Evolucao, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology (IIOAB), West Bengal, India
| | - Andrea Di Cesare
- Water Research Institute (IRSA) - MEG Molecular Ecology Group, CNR - National Research Council of Italy, Verbania, Italy
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Berkvens A, Chauhan P, Bruggeman FJ. Integrative biology of persister cell formation: molecular circuitry, phenotypic diversification and fitness effects. JOURNAL OF THE ROYAL SOCIETY, INTERFACE 2022; 19:20220129. [PMID: 36099930 PMCID: PMC9470271 DOI: 10.1098/rsif.2022.0129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Microbial populations often contain persister cells, which reduce the extinction risk upon sudden stresses. Persister cell formation is deeply intertwined with physiology. Due to this complexity, it cannot be satisfactorily understood by focusing only on mechanistic, physiological or evolutionary aspects. In this review, we take an integrative biology perspective to identify common principles of persister cell formation, which might be applicable across evolutionary-distinct microbes. Persister cells probably evolved to cope with a fundamental trade-off between cellular stress and growth tasks, as any biosynthetic resource investment in growth-supporting proteins is at the expense of stress tasks and vice versa. Natural selection probably favours persister cell subpopulation formation over a single-phenotype strategy, where each cell is prepared for growth and stress to a suboptimal extent, since persister cells can withstand harsher environments and their coexistence with growing cells leads to a higher fitness. The formation of coexisting phenotypes requires bistable molecular circuitry. Bistability probably emerges from growth-modulated, positive feedback loops in the cell's growth versus stress control network, involving interactions between sigma factors, guanosine pentaphosphate and toxin-antitoxin (TA) systems. We conclude that persister cell formation is most likely a response to a sudden reduction in growth rate, which can be achieved by antibiotic addition, nutrient starvation, sudden stresses, nutrient transitions or activation of a TA system.
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Affiliation(s)
- Alicia Berkvens
- Systems Biology Lab, AIMMS, VU University, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
| | - Priyanka Chauhan
- Systems Biology Lab, AIMMS, VU University, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
| | - Frank J Bruggeman
- Systems Biology Lab, AIMMS, VU University, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
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Khan F, Jeong GJ, Tabassum N, Mishra A, Kim YM. Filamentous morphology of bacterial pathogens: regulatory factors and control strategies. Appl Microbiol Biotechnol 2022; 106:5835-5862. [PMID: 35989330 DOI: 10.1007/s00253-022-12128-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/03/2022] [Accepted: 08/06/2022] [Indexed: 11/24/2022]
Abstract
Several studies have demonstrated that when exposed to physical, chemical, and biological stresses in the environment, many bacteria (Gram-positive and Gram-negative) change their morphology from a normal cell to a filamentous shape. The formation of filamentous morphology is one of the survival strategies against environmental stress and protection against phagocytosis or protist predators. Numerous pathogenic bacteria have shown filamentous morphologies when examined in vivo or in vitro. During infection, certain pathogenic bacteria adopt a filamentous shape inside the cell to avoid phagocytosis by immune cells. Filamentous morphology has also been seen in biofilms formed on biotic or abiotic surfaces by certain bacteria. As a result, in addition to protecting against phagocytosis by immune cells or predators, the filamentous shape aids in biofilm adhesion or colonization to biotic or abiotic surfaces. Furthermore, these filamentous morphologies of bacterial pathogens lead to antimicrobial drug resistance. Clinically, filamentous morphology has become one of the most serious challenges in treating bacterial infection. The current review went into great detail about the various factors involved in the change of filamentous morphology and the underlying mechanisms. In addition, the review discussed a control strategy for suppressing filamentous morphology in order to combat bacterial infections. Understanding the mechanism underlying the filamentous morphology induced by various environmental conditions will aid in drug development and lessen the virulence of bacterial pathogens. KEY POINTS: • The bacterial filamentation morphology is one of the survival mechanisms against several environmental stress conditions and protection from phagocytosis by host cells and protist predators. • The filamentous morphologies in bacterial pathogens contribute to enhanced biofilm formation, which develops resistance properties against antimicrobial drugs. • Filamentous morphology has become one of the major hurdles in treating bacterial infection, hence controlling strategies employed for inhibiting the filamentation morphology from combating bacterial infections.
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Affiliation(s)
- Fazlurrahman Khan
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea. .,Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea.
| | - Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Nazia Tabassum
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan, 48513, Republic of Korea
| | - Akanksha Mishra
- Department of Biotechnology, Division of Research and Development, Lovely Professional University, Phagwara, Punjab, 144001, India
| | - Young-Mog Kim
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea. .,Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea. .,Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea.
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58
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Zhang K, Liu L, Yan M, Chen C, Li X, Tian J, Luo C, Wang X, Wang M. Reduced porin expression with EnvZ-OmpR, PhoPQ, BaeSR two-component system down-regulation in carbapenem resistance of Klebsiella Pneumoniae based on proteomic analysis. Microb Pathog 2022; 170:105686. [PMID: 35917986 DOI: 10.1016/j.micpath.2022.105686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 07/15/2022] [Accepted: 07/17/2022] [Indexed: 11/30/2022]
Abstract
Carbapenem-resistant Klebsiella pneumoniae (CRKP) has proven to be an urgent threat to human health. Proteomics (TMT/LC-MS/MS) and bioinformatics approaches were employed to explore the potential mechanisms underlying carbapenem resistance. Proteomic profiling of CRKP and susceptible KP (sKP) isolates revealed the involvement of outer membrane, beta-lactam resistance pathway, and two-component systems (TCSs) in carbapenem resistance. 27 CRKP strains and 27 susceptible Klebsiella pneumoniae strains were isolated from inpatients at the Second Xiangya Hospital, China to verify the mechanisms. Modified carbapenem inactivation method (mCIM) and PCR of common carbapenem resistance genes confirmed that 77.8% (21/27) of CRKP isolates were carbapenemase-producing. Porin decrease in CRKP isolates was found by SDS-PAGE and mRNA levels of major porins (OmpK35 and OmpK36). RT-qPCR detection of two-component systems (envZ, ompR, phoP, phoQ, baeS and baeR) revealed down-regulation of EnvZ-OmpR, PhoPQ, BaeSR TCSs. Expression of the TCSs, except ompR, were closely correlated with OMPs with the R-value >0.7. Together, this study reaffirmed the significance of the β-lactam resistance pathway in CRKP based on proteomic analysis. OmpK35/36 porin reduction and the controversial downregulation of EnvZ-OmpR, PhoPQ, and BaeSR TCSs were confirmed in carbapenem resistance of Klebsiella pneumoniae.
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Affiliation(s)
- Kan Zhang
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Lei Liu
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Min Yan
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Chunmei Chen
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Xianping Li
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Jingjing Tian
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Can Luo
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Xiaofan Wang
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Min Wang
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
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Dawan J, Ahn J. Bacterial Stress Responses as Potential Targets in Overcoming Antibiotic Resistance. Microorganisms 2022; 10:microorganisms10071385. [PMID: 35889104 PMCID: PMC9322497 DOI: 10.3390/microorganisms10071385] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/03/2022] [Accepted: 07/08/2022] [Indexed: 12/23/2022] Open
Abstract
Bacteria can be adapted to adverse and detrimental conditions that induce general and specific responses to DNA damage as well as acid, heat, cold, starvation, oxidative, envelope, and osmotic stresses. The stress-triggered regulatory systems are involved in bacterial survival processes, such as adaptation, physiological changes, virulence potential, and antibiotic resistance. Antibiotic susceptibility to several antibiotics is reduced due to the activation of stress responses in cellular physiology by the stimulation of resistance mechanisms, the promotion of a resistant lifestyle (biofilm or persistence), and/or the induction of resistance mutations. Hence, the activation of bacterial stress responses poses a serious threat to the efficacy and clinical success of antibiotic therapy. Bacterial stress responses can be potential targets for therapeutic alternatives to antibiotics. An understanding of the regulation of stress response in association with antibiotic resistance provides useful information for the discovery of novel antimicrobial adjuvants and the development of effective therapeutic strategies to control antibiotic resistance in bacteria. Therefore, this review discusses bacterial stress responses linked to antibiotic resistance in Gram-negative bacteria and also provides information on novel therapies targeting bacterial stress responses that have been identified as potential candidates for the effective control of Gram-negative antibiotic-resistant bacteria.
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Affiliation(s)
- Jirapat Dawan
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
| | - Juhee Ahn
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
- Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Gangwon, Korea
- Correspondence: ; Tel.: +82-33-250-6564
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Zhang H, Zhou W. Low-energy X-ray irradiation: A novel non-thermal microbial inactivation technology. ADVANCES IN FOOD AND NUTRITION RESEARCH 2022; 100:287-328. [PMID: 35659355 DOI: 10.1016/bs.afnr.2022.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Over the last several decades, food irradiation technology has been proven neither to reduce the nutritional value of foods more than other preservation technologies, nor to make foods radioactive or dangerous to eat. Furthermore, food irradiation is a non-thermal food processing technology that helps preserve more heat sensitive nutrients than those found in thermally processed foods. Conventional food irradiation technologies, including γ-ray, electron beam and high energy X-ray, have certain limitations and drawbacks, such as involving radioactive isotopes, low penetration ability, and economical unfeasibility, respectively. Owing to the recent developments in instrumentation technology, more compact and cheaper tabletop low-energy X-ray sources have become available. The generation of low-energy X-ray, unlike γ-ray, does not involve radioactive isotopes and the cost is lower than high energy X-ray. Furthermore, low-energy X-ray possesses unique advantages, i.e., high linear energy transfer (LET) value and high relative biological effect (RBE) value. The advantages allow low-energy X-ray irradiation to provide a higher microbial inactivation efficacy than γ-ray and high energy X-ray irradiation. In the last few years, various applications reported in the literature indicate that low-energy X-ray irradiation has a great potential to become an alternative food preservation technique. This chapter discusses the technical advances of low-energy X-ray irradiation, microbial inactivation mechanism, factors influencing its efficiency, current applications, consumer acceptance, and limitations.
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Affiliation(s)
- Hongfei Zhang
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
| | - Weibiao Zhou
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore.
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Sharma G, Curtis PD. The Impacts of Microgravity on Bacterial Metabolism. Life (Basel) 2022; 12:life12060774. [PMID: 35743807 PMCID: PMC9225508 DOI: 10.3390/life12060774] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/18/2022] [Accepted: 05/20/2022] [Indexed: 12/15/2022] Open
Abstract
The inside of a space-faring vehicle provides a set of conditions unlike anything experienced by bacteria on Earth. The low-shear, diffusion-limited microenvironment with accompanying high levels of ionizing radiation create high stress in bacterial cells, and results in many physiological adaptations. This review gives an overview of the effect spaceflight in general, and real or simulated microgravity in particular, has on primary and secondary metabolism. Some broad trends in primary metabolic responses can be identified. These include increases in carbohydrate metabolism, changes in carbon substrate utilization range, and changes in amino acid metabolism that reflect increased oxidative stress. However, another important trend is that there is no universal bacterial response to microgravity, as different bacteria often have contradictory responses to the same stress. This is exemplified in many of the observed secondary metabolite responses where secondary metabolites may have increased, decreased, or unchanged production in microgravity. Different secondary metabolites in the same organism can even show drastically different production responses. Microgravity can also impact the production profile and localization of secondary metabolites. The inconsistency of bacterial responses to real or simulated microgravity underscores the importance of further research in this area to better understand how microbes can impact the people and systems aboard spacecraft.
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Muurinen J, Cairns J, Ekakoro JE, Wickware CL, Ruple A, Johnson TA. Biological units of antimicrobial resistance and strategies for their containment in animal production. FEMS Microbiol Ecol 2022; 98:6589402. [PMID: 35587376 DOI: 10.1093/femsec/fiac060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 05/27/2022] [Indexed: 11/14/2022] Open
Abstract
The increasing prevalence of antimicrobial resistant bacterial infections has ushered in a major global public health crisis. Judicious or restricted antimicrobial use in animal agriculture, aiming to confine the use for the treatment of infections, is the most commonly proposed solution to reduce selection pressure for resistant bacterial strains and resistance genes. However, a multifaceted solution will likely be required to make acceptable progress in reducing antimicrobial resistance, due to other common environmental conditions maintaining antimicrobial resistance and limited executionary potential as human healthcare and agriculture will continue to rely heavily on antimicrobials in the foreseeable future. Drawing parallels from systematic approaches to the management of infectious disease agents and biodiversity loss, we provide examples that a more comprehensive approach is required, targeting antimicrobial resistance in agroecosystems on multiple fronts simultaneously. We present one such framework, based on nested biological units of antimicrobial resistance, and describe established or innovative strategies targeting units. Some of the proposed strategies are already in use or ready to be implemented, while some require further research and discussion among scientists and policymakers. We envision that antimicrobial resistance mitigation strategies for animal agriculture combining multiple tools would constitute powerful ecosystem-level interventions necessary to mitigate antimicrobial resistance.
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Affiliation(s)
- Johanna Muurinen
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA.,Department of Microbiology, Viikinkaari 9, 00014 University of Helsinki, Helsinki, Finland
| | - Johannes Cairns
- Organismal and Evolutionary Biology Research Programme (OEB), Department of Computer Science, 00014 University of Helsinki, Helsinki, Finland
| | - John Eddie Ekakoro
- Department of Public and Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Carmen L Wickware
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
| | - Audrey Ruple
- Department of Population Health Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Timothy A Johnson
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
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Chiș AA, Rus LL, Morgovan C, Arseniu AM, Frum A, Vonica-Țincu AL, Gligor FG, Mureșan ML, Dobrea CM. Microbial Resistance to Antibiotics and Effective Antibiotherapy. Biomedicines 2022; 10:biomedicines10051121. [PMID: 35625857 PMCID: PMC9138529 DOI: 10.3390/biomedicines10051121] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 12/24/2022] Open
Abstract
Currently, the efficacy of antibiotics is severely affected by the emergence of the antimicrobial resistance phenomenon, leading to increased morbidity and mortality worldwide. Multidrug-resistant pathogens are found not only in hospital settings, but also in the community, and are considered one of the biggest public health concerns. The main mechanisms by which bacteria develop resistance to antibiotics include changes in the drug target, prevention of entering the cell, elimination through efflux pumps or inactivation of drugs. A better understanding and prediction of resistance patterns of a pathogen will lead to a better selection of active antibiotics for the treatment of multidrug-resistant infections.
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Ng HF, Ngeow YF. Genetic Determinants of Tigecycline Resistance in Mycobacteroides abscessus. Antibiotics (Basel) 2022; 11:antibiotics11050572. [PMID: 35625216 PMCID: PMC9137676 DOI: 10.3390/antibiotics11050572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/14/2022] [Accepted: 04/18/2022] [Indexed: 02/01/2023] Open
Abstract
Mycobacteroides abscessus (formerly Mycobacterium abscessus) is a clinically important, rapid-growing non-tuberculous mycobacterium notoriously known for its multidrug-resistance phenotype. The intrinsic resistance of M. abscessus towards first- and second-generation tetracyclines is mainly due to the over-expression of a tetracycline-degrading enzyme known as MabTetX (MAB_1496c). Tigecycline, a third-generation tetracycline, is a poor substrate for the MabTetX and does not induce the expression of this enzyme. Although tigecycline-resistant strains of M. abscessus have been documented in different parts of the world, their resistance determinants remain largely elusive. Recent work on tigecycline resistance or reduced susceptibility in M. abscessus revealed the involvement of the gene MAB_3508c which encodes the transcriptional activator WhiB7, as well as mutations in the sigH-rshA genes which control heat shock and oxidative-stress responses. The deletion of whiB7 has been observed to cause a 4-fold decrease in the minimum inhibitory concentration of tigecycline. In the absence of environmental stress, the SigH sigma factor (MAB_3543c) interacts with and is inhibited by the anti-sigma factor RshA (MAB_3542c). The disruption of the SigH-RshA interaction resulting from mutations and the subsequent up-regulation of SigH have been hypothesized to lead to tigecycline resistance in M. abscessus. In this review, the evidence for different genetic determinants reported to be linked to tigecycline resistance in M. abscessus was examined and discussed.
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Marmion M, Macori G, Whyte P, Scannell AGM. Stress response modulation: the key to survival of pathogenic and spoilage bacteria during poultry processing. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35451951 DOI: 10.1099/mic.0.001184] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The control of bacterial contaminants on meat is a key area of interest in the food industry. Bacteria are exposed to a variety of stresses during broiler processing which challenge bacterial structures and metabolic pathways causing death or sublethal injury. To counter these stresses, bacteria possess robust response systems that can induce shifts in the transcriptome and proteome to enable survival. Effective adaptive responses, such as biofilm formation, shock protein production and metabolic flexibility, require rapid induction and implementation at a cellular and community level to facilitate bacterial survival in adverse conditions. This review aims to provide an overview of the scientific literature pertaining to the regulation of complex adaptive processes used by bacteria to survive the processing environment, with particular focus on species that impact the quality and safety of poultry products like Campylobacter spp., Salmonella enterica and Pseudomonas spp.
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Affiliation(s)
- Maitiú Marmion
- UCD School of Agriculture and Food Science, Belfield, Dublin 4, D04V4W8, Ireland.,UCD Centre for Food Safety, University College Dublin, Belfield, Dublin 4, D04V4W8, Ireland
| | - Guerrino Macori
- UCD School of Agriculture and Food Science, Belfield, Dublin 4, D04V4W8, Ireland.,UCD Centre for Food Safety, University College Dublin, Belfield, Dublin 4, D04V4W8, Ireland
| | - Paul Whyte
- UCD School of Veterinary Medicine, Belfield, Dublin 4, D04V4W8, Ireland
| | - Amalia G M Scannell
- UCD School of Agriculture and Food Science, Belfield, Dublin 4, D04V4W8, Ireland.,UCD Centre for Food Safety, University College Dublin, Belfield, Dublin 4, D04V4W8, Ireland.,UCD Institute of Food and Health, Belfield, Dublin 4, D04V4W8, Ireland
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66
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Awuor SO, Omwenga EO, Mariita RM, Daud II. Cholera outbreak: antibiofilm activity, profiling of antibiotic-resistant genes and virulence factors of toxigenic Vibrio cholerae isolates reveals concerning traits. Access Microbiol 2022; 4:000324. [PMID: 35693465 PMCID: PMC9175979 DOI: 10.1099/acmi.0.000324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/23/2021] [Indexed: 11/28/2022] Open
Abstract
Vibrio cholerae is a biofilm-forming pathogen with various virulence phenotypes and antimicrobial resistance traits. Phenotypic characteristics play a critical role in disease transmission and pathogenesis. The current study elucidated antibiofilm formation activity, profiled antibiotic-resistant genes and virulence factors of toxigenic Vibrio cholerae isolates from the cholera outbreak in Kisumu County, Kenya. Vibrio cholerae O1 isolates collected during the 2017 cholera outbreak in Kisumu County, Kenya, were utilized. Biofilm and virulence factors were profiled using standard procedures. The study confirmed 100 isolates as Vibrio cholerae, with 81 of them possessing cholera toxin gene (ctxA). Additionally, 99 of the isolates harboured the toxR gene. The study further revealed that 81 and 94 of the isolates harboured the class I integron (encoded by inDS gene) and integrating conjugative element (ICE), respectively. Antibiotic resistance assays confirmed tetracycline resistance genes as the most abundant (97 isolates). Among them were seven isolates resistant to commonly used antibiotics. The study further screened the isolates for antibiofilm formation using various antibiotics. Unlike the four strains (03/17–16, 02/17–09, 04/17–13), three of the strains (04/17–07, 06/17–14 and 05/17–03) did not form biofilms. Further, all the seven isolates that exhibited extensive antibiotic resistance produced haemolysin while 71.42%, 85.71 and 71.42 % of them produced protease, phospholipases and lipase, respectively. This study provides and in-depth understanding of essential features that were possibly responsible for V. cholerae outbreak. Understanding of these features is critical in the development of strategies to combat future outbreaks.
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Affiliation(s)
- Silas O. Awuor
- School of Health Sciences, Kisii University, P.O BOX 408-40200 Kisii, Kenya
| | - Eric O. Omwenga
- School of Health Sciences, Kisii University, P.O BOX 408-40200 Kisii, Kenya
| | | | - Ibrahim I. Daud
- Kenya Medical Research Institute, United States Army Medical Research Directorate-Africa, HJF Medical Research International, Kericho, Kenya
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Wang S, Huang A, Gu Y, Li J, Huang L, Wang X, Tao Y, Liu Z, Wu C, Yuan Z, Hao H. Rational Use of Danofloxacin for Treatment of Mycoplasma gallisepticum in Chickens Based on the Clinical Breakpoint and Lung Microbiota Shift. Antibiotics (Basel) 2022; 11:antibiotics11030403. [PMID: 35326865 PMCID: PMC8944443 DOI: 10.3390/antibiotics11030403] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/11/2022] [Accepted: 03/13/2022] [Indexed: 02/01/2023] Open
Abstract
The study was to explore the rational use of danofloxacin against Mycoplasma gallisepticum (MG) based on its clinical breakpoint (CBP) and the effect on lung microbiota. The CBP was established according to epidemiological cutoff value (ECV/COWT), pharmacokinetic–pharmacodynamic (PK–PD) cutoff value (COPD) and clinical cutoff value (COCL). The ECV was determined by the micro-broth dilution method and analyzed by ECOFFinder software. The COPD was determined according to PK–PD modeling of danofloxacin in infected lung tissue with Monte Carlo analysis. The COCL was performed based on the relationship between the minimum inhibitory concentration (MIC) and the possibility of cure (POC) from clinical trials. The CBP in infected lung tissue was 1 μg/mL according to CLSI M37-A3 decision tree. The 16S ribosomal RNA (rRNA) sequencing results showed that the lung microbiota, especially the phyla Firmicutes and Proteobacteria had changed significantly along with the process of cure regimen (the 24 h dosing interval of 16.60 mg/kg b.w for three consecutive days). Our study suggested that the rational use of danofloxacin for the treatment of MG infections should consider the MIC and effect of antibiotics on the respiratory microbiota.
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Affiliation(s)
- Shuge Wang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; (S.W.); (A.H.); (Y.G.); (L.H.); (X.W.); (Y.T.); (Z.L.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan 430070, China
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China;
| | - Anxiong Huang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; (S.W.); (A.H.); (Y.G.); (L.H.); (X.W.); (Y.T.); (Z.L.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan 430070, China
| | - Yufeng Gu
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; (S.W.); (A.H.); (Y.G.); (L.H.); (X.W.); (Y.T.); (Z.L.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan 430070, China
| | - Jun Li
- Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China;
| | - Lingli Huang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; (S.W.); (A.H.); (Y.G.); (L.H.); (X.W.); (Y.T.); (Z.L.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan 430070, China
| | - Xu Wang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; (S.W.); (A.H.); (Y.G.); (L.H.); (X.W.); (Y.T.); (Z.L.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan 430070, China
| | - Yanfei Tao
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; (S.W.); (A.H.); (Y.G.); (L.H.); (X.W.); (Y.T.); (Z.L.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan 430070, China
| | - Zhenli Liu
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; (S.W.); (A.H.); (Y.G.); (L.H.); (X.W.); (Y.T.); (Z.L.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan 430070, China
| | - Congming Wu
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China;
| | - Zonghui Yuan
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; (S.W.); (A.H.); (Y.G.); (L.H.); (X.W.); (Y.T.); (Z.L.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan 430070, China
| | - Haihong Hao
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan 430070, China; (S.W.); (A.H.); (Y.G.); (L.H.); (X.W.); (Y.T.); (Z.L.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Wuhan 430070, China
- Correspondence: ; Tel.: +86-27-87287186; Fax: +86-27-87672232
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Tailor K, Sagar P, Dave K, Pohnerkar J. Fusion of the N-terminal 119 amino acids of RelA with the CTD domain render growth inhibitory effects of the latter, (p)ppGpp-dependent. Mol Genet Genomics 2022; 297:601-620. [PMID: 35238978 DOI: 10.1007/s00438-022-01873-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 02/10/2022] [Indexed: 10/18/2022]
Abstract
The guanosine nucleotide derivatives ppGpp and pppGpp are central to the remarkable capacity of bacteria to adapt to fluctuating environments and metabolic perturbations. They are synthesized by two proteins, RelA and SpoT in E. coli and the activities of each of the two enzymes are highly regulated for homeostatic control of intracellular (p)ppGpp levels. Characterization of the mutant studied here indicates that moderate level expression of RelA appreciably reduces growth of cells wherein the basal levels of (p)ppGpp are higher than in the wild type without elevating the levels further. Consistent with this result, a large part of the growth inhibition effect is reproduced by overexpression of RelA NTD-CTD fusion lacking the (p)ppGpp synthesis function. A null mutation in relA abolishes this growth inhibitory effect suggesting its requirement for basal level synthesis of (p)ppGpp. Accordingly, increase in the (p)ppGpp levels in the relA1 mutant by spoT202 mutation largely restored the growth inhibitory effects of overexpression of RelA NTD-CTD fusion. Expression of this construct consisting of 119 amino acids of the N-terminal hydrolytic domain (HD) fused in-frame with the CTD domain (±TGS domain) renders the growth inhibitory effects (p)ppGpp-responsive-inhibited growth only of spoT1 and spoT202 relA1 mutants. This finding uncovered an hitherto unrealized (p)ppGpp-dependent regulation of RelA-CTD function, unraveling the importance of RelA NTD-HD domain for its regulatory role. An incremental rise in the (p)ppGpp levels is proposed to progressively modulate the interaction of RelA-CTD with the ribosomes with possible implications in the feedback regulation of the (p)ppGpp synthesis function, a proposal that accounts for the nonlinear kinetics of (p)ppGpp synthesis and increased ratio of RelA:ribosomes, both in vitro as well as in vivo.
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Affiliation(s)
- Krishma Tailor
- Department of Biochemistry, Faculty of Science, Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, 390002, India
| | - Prarthi Sagar
- Department of Biochemistry, Faculty of Science, Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, 390002, India
| | - Keyur Dave
- Department of Biochemistry, Faculty of Science, Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, 390002, India
| | - Jayashree Pohnerkar
- Department of Biochemistry, Faculty of Science, Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, 390002, India.
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69
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Marmion M, Macori G, Ferone M, Whyte P, Scannell A. Survive and thrive: Control mechanisms that facilitate bacterial adaptation to survive manufacturing-related stress. Int J Food Microbiol 2022; 368:109612. [DOI: 10.1016/j.ijfoodmicro.2022.109612] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/21/2022] [Accepted: 03/02/2022] [Indexed: 10/18/2022]
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Joshi C, Kothari V. Bacterial Stress-response Machinery as a Target for Next-generation Antimicrobials. Infect Disord Drug Targets 2022; 22:e210322202493. [PMID: 35319398 DOI: 10.2174/1871526522666220321153332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 10/30/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Affiliation(s)
- Chinmayi Joshi
- Smt. S.S.Patel Nootan Science and Commerce College, Sankalchand Patel University, Visnagar 384315, India
| | - Vijay Kothari
- Institute of Science, Nirma University, Ahmedabad 382481, India
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71
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Li J, Claudi B, Fanous J, Chicherova N, Cianfanelli FR, Campbell RAA, Bumann D. Tissue compartmentalization enables Salmonella persistence during chemotherapy. Proc Natl Acad Sci U S A 2021; 118:e2113951118. [PMID: 34911764 PMCID: PMC8713819 DOI: 10.1073/pnas.2113951118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2021] [Indexed: 12/14/2022] Open
Abstract
Antimicrobial chemotherapy can fail to eradicate the pathogen, even in the absence of antimicrobial resistance. Persisting pathogens can subsequently cause relapsing diseases. In vitro studies suggest various mechanisms of antibiotic persistence, but their in vivo relevance remains unclear because of the difficulty of studying scarce pathogen survivors in complex host tissues. Here, we localized and characterized rare surviving Salmonella in mouse spleen using high-resolution whole-organ tomography. Chemotherapy cleared >99.5% of the Salmonella but was inefficient against a small Salmonella subset in the white pulp. Previous models could not explain these findings: drug exposure was adequate, Salmonella continued to replicate, and host stresses induced only limited Salmonella drug tolerance. Instead, antimicrobial clearance required support of Salmonella-killing neutrophils and monocytes, and the density of such cells was lower in the white pulp than in other spleen compartments containing higher Salmonella loads. Neutrophil densities declined further during treatment in response to receding Salmonella loads, resulting in insufficient support for Salmonella clearance from the white pulp and eradication failure. However, adjunctive therapies sustaining inflammatory support enabled effective clearance. These results identify uneven Salmonella tissue colonization and spatiotemporal inflammation dynamics as main causes of Salmonella persistence and establish a powerful approach to investigate scarce but impactful pathogen subsets in complex host environments.
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Affiliation(s)
- Jiagui Li
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | | | - Joseph Fanous
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | | | | | | | - Dirk Bumann
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
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Zadeh RG, Kalani BS, Ari MM, Talebi M, Razavi S, Jazi FM. Isolation of Persister Cell within the Biofilm and Relative Gene Expression Analysis of Type II Toxin-antitoxin System in Pseudomonas aeruginosa Isolates in the Exponential and Stationary Phases. J Glob Antimicrob Resist 2021; 28:30-37. [PMID: 34922056 DOI: 10.1016/j.jgar.2021.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/22/2021] [Accepted: 11/22/2021] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES Chronic infections and treatment failure are concerning issues in patients with Pseudomonas aeruginosa infections. Persister cell formation in biofilm is considered a key reason for antibiotic resistance and treatment failure. Thus, in this study, the expression of TA type II system genes (relBE, Xre-COG5654, vapBC, and Xre-GNAT) in persister cells of biofilm was evaluated in the presence of ciprofloxacin and colistin antibiotics during exponential and stationary phases. METHODS The impacts of ciprofloxacin and colistin were examined on persister cell formation of biofilm during the exponential and stationary phases of P. aeruginosa strains through colony count method at different time intervals in the presence of 5-fold MIC of ciprofloxacin and colistin. Furthermore, the expression of relBE, Xre-COG5654, vapBC, and Xre-GNAT genes in P. aeruginosa strains underwent antibiotic treatment for 3.5 hours during the exponential and stationary phases via qRT-PCR. RESULTS Formation of persister cells was observed in the biofilms by P. aeruginosa strains in the presence of 5-fold MIC of ciprofloxacin and colistin when compared with the control group after 3.5 hours of incubation during both exponential and stationary phases. The number of persister cells of biofilm was higher in the stationary phase than in the exponential phase. According to the findings of qRT-PCR, ciprofloxacin and colistin may induce persister cells through enhancing the expression of type II TA systems during stationary and exponential phases. CONCLUSION The result of this study indicated that ciprofloxacin and colistin have the potential to increase persister cells formation in biofilm through influencing the expression of type II TA systems.
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Affiliation(s)
- Rezvan Golmoradi Zadeh
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Behrooz Sadeghi Kalani
- Department of Microbiology, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran; Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Marzie Mahdizade Ari
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Malihe Talebi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Shabnam Razavi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Faramarz Masjedian Jazi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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73
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Flavonoids as Inhibitors of Bacterial Efflux Pumps. Molecules 2021; 26:molecules26226904. [PMID: 34833994 PMCID: PMC8625893 DOI: 10.3390/molecules26226904] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 11/17/2022] Open
Abstract
Flavonoids are widely occurring secondary plant constituents, and are abundant in vegetable and fruit diets as well as herbal medicines. Therapeutic treatment options for bacterial infections are limited due to the spread of antimicrobial resistances. Hence, in a number of studies during the last few years, different classes of plant secondary metabolites as resistance-modifying agents have been carried out. In this review, we present the role of flavonoids as inhibitors of bacterial efflux pumps. Active compounds could be identified in the subclasses of chalcones, flavan-3-ols, flavanones, flavones, flavonols, flavonolignans and isoflavones; by far the majority of compounds were aglycones, although some glycosides like kaempferol glycosides with p-coumaroyl acylation showed remarkable results. Staphylococcus aureus NorA pump was the focus of many studies, followed by mycobacteria, whereas Gram-negative bacteria are still under-investigated.
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74
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Shein AMS, Wannigama DL, Higgins PG, Hurst C, Abe S, Hongsing P, Chantaravisoot N, Saethang T, Luk-in S, Liao T, Nilgate S, Rirerm U, Kueakulpattana N, Laowansiri M, Srisakul S, Muhummudaree N, Techawiwattanaboon T, Gan L, Xu C, Kupwiwat R, Phattharapornjaroen P, Rojanathanes R, Leelahavanichkul A, Chatsuwan T. Novel colistin-EDTA combination for successful eradication of colistin-resistant Klebsiella pneumoniae catheter-related biofilm infections. Sci Rep 2021; 11:21676. [PMID: 34737361 PMCID: PMC8568960 DOI: 10.1038/s41598-021-01052-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/20/2021] [Indexed: 12/20/2022] Open
Abstract
Development of an effective therapy to overcome colistin resistance in Klebsiella pneumoniae, a common pathogen causing catheter-related biofilm infections in vascular catheters, has become a serious therapeutic challenge that must be addressed urgently. Although colistin and EDTA have successful roles for eradicating biofilms, no in vitro and in vivo studies have investigated their efficacy in catheter-related biofilm infections of colistin-resistant K. pneumoniae. In this study, colistin resistance was significantly reversed in both planktonic and mature biofilms of colistin-resistant K. pneumoniae by a combination of colistin (0.25-1 µg/ml) with EDTA (12 mg/ml). This novel colistin-EDTA combination was also demonstrated to have potent efficacy in eradicating colistin-resistant K. pneumoniae catheter-related biofilm infections, and eliminating the risk of recurrence in vivo. Furthermore, this study revealed significant therapeutic efficacy of colistin-EDTA combination in reducing bacterial load in internal organs, lowering serum creatinine, and protecting treated mice from mortality. Altered in vivo expression of different virulence genes indicate bacterial adaptive responses to survive in hostile environments under different treatments. According to these data discovered in this study, a novel colistin-EDTA combination provides favorable efficacy and safety for successful eradication of colistin-resistant K. pneumonia catheter-related biofilm infections.
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Affiliation(s)
- Aye Mya Sithu Shein
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Interdisciplinary Program of Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Dhammika Leshan Wannigama
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand ,grid.1012.20000 0004 1936 7910School of Medicine, Faculty of Health and Medical Sciences, The University of Western Australia, Nedlands, WA Australia
| | - Paul G. Higgins
- grid.6190.e0000 0000 8580 3777Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany ,grid.6190.e0000 0000 8580 3777Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany ,German Centre for Infection Research, Partner Site Bonn-Cologne, Cologne, Germany
| | - Cameron Hurst
- grid.1049.c0000 0001 2294 1395Statistics, QIMR Berghofer Medical Research Institute, Brisbane, QLD Australia
| | - Shuichi Abe
- grid.417323.00000 0004 1773 9434Department of Infectious Diseases and Infection Control, Yamagata Prefectural Central Hospital, Yamagata, Japan
| | - Parichart Hongsing
- grid.411554.00000 0001 0180 5757Mae Fah Luang University Hospital, Chiang Rai, Thailand ,grid.411554.00000 0001 0180 5757School of Integrative Medicine, Mae Fah Luang University, Chiang Rai, Thailand
| | - Naphat Chantaravisoot
- grid.7922.e0000 0001 0244 7875Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Center of Excellence in Systems Biology, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Thammakorn Saethang
- grid.9723.f0000 0001 0944 049XDepartment of Computer Science, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Sirirat Luk-in
- grid.10223.320000 0004 1937 0490Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Tingting Liao
- grid.7922.e0000 0001 0244 7875Department of Physiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Center of Excellence for Microcirculation, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Sumanee Nilgate
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Ubolrat Rirerm
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Naris Kueakulpattana
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Matchima Laowansiri
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Sukrit Srisakul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Netchanok Muhummudaree
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Teerasit Techawiwattanaboon
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Chula Vaccine Research Center, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Lin Gan
- grid.490170.bDepartment of General Surgery, Fuling Center Hospital of Chongqing City, Chongqing, China
| | - Chenchen Xu
- grid.412676.00000 0004 1799 0784In-Patient Pharmacy, Jiangsu Province Hospital, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Rosalyn Kupwiwat
- grid.412434.40000 0004 1937 1127Chulabhorn International College of Medicine, Thammasat University, Thammasat University Hospital, Bangkok, Thailand
| | - Phatthranit Phattharapornjaroen
- grid.10223.320000 0004 1937 0490Department of Emergency Medicine, Center of Excellence, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand ,grid.8761.80000 0000 9919 9582Institute of Clinical Sciences, Department of Surgery, Sahlgrenska Academy, Gothenburg University, 40530 Gothenburg, Sweden
| | - Rojrit Rojanathanes
- grid.7922.e0000 0001 0244 7875Center of Excellence in Materials and Bio-Interfaces, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Asada Leelahavanichkul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Translational Research in Inflammation and Immunology Research Unit (TRIRU), Department of Microbiology, Chulalongkorn University, Bangkok, Thailand
| | - Tanittha Chatsuwan
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand ,grid.7922.e0000 0001 0244 7875Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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Jeon B, Luangtongkum T, Shen Z, Logue CM, Lin J. Editorial: Resistance and Tolerance in Food-Borne Pathogens: Mechanisms, Public Health Impact, and Control Measures. Front Microbiol 2021; 12:769931. [PMID: 34721371 PMCID: PMC8551716 DOI: 10.3389/fmicb.2021.769931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 09/20/2021] [Indexed: 12/01/2022] Open
Affiliation(s)
- Byeonghwa Jeon
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, MN, United States
| | - Taradon Luangtongkum
- Department of Veterinary Public Health, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Zhangqi Shen
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, Beijing Laboratory of Food Quality and Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Catherine M Logue
- Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Jun Lin
- Department of Animal Science, University of Tennessee, Knoxville, Knoxville, TN, United States
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76
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Bombaywala S, Purohit HJ, Dafale NA. Mobility of antibiotic resistance and its co-occurrence with metal resistance in pathogens under oxidative stress. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 297:113315. [PMID: 34298350 DOI: 10.1016/j.jenvman.2021.113315] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/08/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
The bacterial communities are challenged with oxidative stress during their exposure to bactericidal antibiotics, metals, and different levels of dissolved oxygen (DO) encountered in diverse environmental habitats. The frequency of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) co-selection is increased by selective pressure posed by oxidative stress. Hence, study of resistance acquisition is important from an evolutionary perspective. To understand the dependence of oxidative stress on the dissemination of ARGs and MRGs through a pathogenic bacterial population, 12 metagenomes belonging to gut, water and soil habitats were evaluated. The metagenome-wide analysis showed the chicken gut to pose the most diverse pool of ARGs (30.4 ppm) and pathogenic bacteria (Simpson diversity = 0.98). The most common types of resistances found in all the environmental samples were efflux pumps (13.22 ppm) and genes conferring resistance to vancomycin (12.4 ppm), tetracycline (12.1 ppm), or beta-lactam (9.4 ppm) antibiotics. Additionally, limiting DO level in soil was observed to increase the abundance of excision nucleases (uvrA and uvrB), DNA polymerase (polA), catalases (katG), and other oxidative stress response genes (OSGs). This was further evident from major variations occurred in antibiotic efflux genes due to the effect of DO concentration on two human pathogens, namely Salmonella enterica and Shigella sonnei found in all the selected habitats. In conclusion, the microbial community, when challenged with oxidative stress caused by environmental variations in oxygen level, tends to accumulate higher amounts of ARGs with increased dissemination potential through triggering non-lethal mutagenesis. Furthermore, the genetic linkage or co-occurrence of ARGs and MRGs provides evidence for selecting ARGs under high concentrations of heavy metals.
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Affiliation(s)
- Sakina Bombaywala
- Environmental Biotechnology & Genomics Division, CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, 4400 20, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Hemant J Purohit
- Environmental Biotechnology & Genomics Division, CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, 4400 20, India
| | - Nishant A Dafale
- Environmental Biotechnology & Genomics Division, CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur, 4400 20, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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77
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Costello KM, Velliou E, Gutierrez-Merino J, Smet C, Kadri HE, Impe JFV, Bussemaker M. The effect of ultrasound treatment in combination with nisin on the inactivation of Listeria innocua and Escherichia coli. ULTRASONICS SONOCHEMISTRY 2021; 79:105776. [PMID: 34662803 PMCID: PMC8560821 DOI: 10.1016/j.ultsonch.2021.105776] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/27/2021] [Accepted: 09/29/2021] [Indexed: 05/21/2023]
Abstract
Ultrasound, alone or in combination with natural antimicrobials, is a novel food processing technology of interest to replace traditional food decontamination methods, as it is milder than classical sterilisation (heat treatment) and maintains desirable sensory characteristics. However, ultrasound efficacy can be affected by food structure/composition, as well as the order in which combined treatments are applied. More specifically, treatments which target different cell components could result in enhanced inactivation if applied in the appropriate order. The microbial properties i.e. Gram positive/Gram negative can also impact the treatment efficacy. This work presents a systematic study of the combined effect of ultrasound and nisin on the inactivation of the bacteria Listeria innocua (Gram positive) and Escherichia coli (Gram negative), at a range of cavitation conditions (44, 500, 1000 kHz). The order of treatment application was varied, and the impact of system structure was also investigated by varying the concentration of Xanthan gum used to create the food model systems (0 - 0.5% w/v). Microbial inactivation kinetics were monitored, and advanced microscopy and flow cytometry techniques were utilised to quantify the impact of treatment on a cellular level. Ultrasound was shown to be effective against E. coli at 500 kHz only, with L. innocua demonstrating resistance to all frequencies studied. Enhanced inactivation of E. coli was observed for the combination of nisin and ultrasound at 500 kHz, but only when nisin was applied before ultrasound treatment. The system structure negatively impacted the inactivation efficacy. The combined effect of ultrasound and nisin on E. coli was attributed to short-lived destabilisation of the outer membrane as a result of sonication, allowing nisin to penetrate the cytoplasmic membrane and facilitate cell inactivation.
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Affiliation(s)
- Katherine M Costello
- Department of Chemical and Process Engineering, University of Surrey, Guildford GU2 7XH, UK.
| | - Eirini Velliou
- Department of Chemical and Process Engineering, University of Surrey, Guildford GU2 7XH, UK; Centre for 3D Models of Health and Disease, Division of Surgery and Interventional Science, University College London, London W1W 7TY, UK
| | | | - Cindy Smet
- BioTeC+ Chemical and Biochemical Process Technology and Control, KU Leuven Campus Gent, Gent, Belgium
| | - Hani El Kadri
- Department of Chemical and Process Engineering, University of Surrey, Guildford GU2 7XH, UK
| | - Jan F Van Impe
- BioTeC+ Chemical and Biochemical Process Technology and Control, KU Leuven Campus Gent, Gent, Belgium
| | - Madeleine Bussemaker
- Department of Chemical and Process Engineering, University of Surrey, Guildford GU2 7XH, UK.
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78
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Silvis MR, Rajendram M, Shi H, Osadnik H, Gray AN, Cesar S, Peters JM, Hearne CC, Kumar P, Todor H, Huang KC, Gross CA. Morphological and Transcriptional Responses to CRISPRi Knockdown of Essential Genes in Escherichia coli. mBio 2021; 12:e0256121. [PMID: 34634934 PMCID: PMC8510551 DOI: 10.1128/mbio.02561-21] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 01/03/2023] Open
Abstract
CRISPR interference (CRISPRi) has facilitated the study of essential genes in diverse organisms using both high-throughput and targeted approaches. Despite the promise of this technique, no comprehensive arrayed CRISPRi library targeting essential genes exists for the model bacterium Escherichia coli, or for any Gram-negative species. Here, we built and characterized such a library. Each of the ∼500 strains in our E. coli library contains an inducible, chromosomally integrated single guide RNA (sgRNA) targeting an essential (or selected nonessential) gene and can be mated with a pseudo-Hfr donor strain carrying a dcas9 cassette to create a CRISPRi knockdown strain. Using this system, we built an arrayed library of CRISPRi strains and performed population and single-cell growth and morphology measurements as well as targeted follow-up experiments. These studies found that inhibiting translation causes an extended lag phase, identified new modulators of cell morphology, and revealed that the morphogene mreB is subject to transcriptional feedback regulation, which is critical for the maintenance of morphology. Our findings highlight canonical and noncanonical roles for essential genes in numerous aspects of cellular homeostasis. IMPORTANCE Essential genes make up only ∼5 to 10% of the genetic complement in most organisms but occupy much of their protein synthesis and account for almost all antibiotic targets. Despite the importance of essential genes, their intractability has, until recently, hampered efforts to study them. CRISPRi has facilitated the study of essential genes by allowing inducible and titratable depletion. However, all large-scale CRISPRi studies in Gram-negative bacteria thus far have used plasmids to express CRISPRi components and have been constructed in pools, limiting their utility for targeted assays and complicating the determination of antibiotic effects. Here, we use a modular method to construct an arrayed library of chromosomally integrated CRISPRi strains targeting the essential genes of the model bacterium Escherichia coli. This library enables targeted studies of essential gene depletions and high-throughput determination of antibiotic targets and facilitates studies targeting the outer membrane, an essential component that serves as the major barrier to antibiotics.
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Affiliation(s)
- Melanie R. Silvis
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Manohary Rajendram
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Handuo Shi
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Hendrik Osadnik
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Andrew N. Gray
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Spencer Cesar
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Jason M. Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Cameron C. Hearne
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Parth Kumar
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Horia Todor
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
| | - Carol A. Gross
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
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79
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Schwan CL, Lomonaco S, Bastos LM, Cook PW, Maher J, Trinetta V, Bhullar M, Phebus RK, Gragg S, Kastner J, Vipham JL. Genotypic and Phenotypic Characterization of Antimicrobial Resistance Profiles in Non-typhoidal Salmonella enterica Strains Isolated From Cambodian Informal Markets. Front Microbiol 2021; 12:711472. [PMID: 34603240 PMCID: PMC8481621 DOI: 10.3389/fmicb.2021.711472] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/26/2021] [Indexed: 12/03/2022] Open
Abstract
Non-typhoidal Salmonella enterica is a pathogen of global importance, particularly in low and middle-income countries (LMICs). The presence of antimicrobial resistant (AMR) strains in market environments poses a serious health threat to consumers. In this study we identified and characterized the genotypic and phenotypic AMR profiles of 81 environmental S. enterica strains isolated from samples from informal markets in Cambodia in 2018–2019. AMR genotypes were retrieved from the NCBI Pathogen Detection website (https://www.ncbi.nlm.nih.gov/pathogens/) and using ResFinder (https://cge.cbs.dtu.dk/services/) Salmonella pathogenicity islands (SPIs) were identified with SPIFinder (https://cge.cbs.dtu.dk/services/). Susceptibility testing was performed by broth microdilution according to the Clinical and Laboratory Standards Institute (CLSI) standard guidelines M100-S22 using the National Antimicrobial Resistance Monitoring System (NARMS) Sensititre Gram Negative plate. A total of 17 unique AMR genes were detected in 53% (43/81) of the isolates, including those encoding tetracycline, beta-lactam, sulfonamide, quinolone, aminoglycoside, phenicol, and trimethoprim resistance. A total of 10 SPIs (SPI-1, 3–5, 8, 9, 12–14, and centisome 63 [C63PI]) were detected in 59 isolates. C63PI, an iron transport system in SPI-1, was observed in 56% of the isolates (n = 46). SPI-1, SPI-4, and SPI-9 were present in 13, 2, and 5% of the isolates, respectively. The most common phenotypic resistances were observed to tetracycline (47%; n = 38), ampicillin (37%; n = 30), streptomycin (20%; n = 16), chloramphenicol (17%; n = 14), and trimethoprim-sulfamethoxazole (16%; n = 13). This study contributes to understanding the AMR genes present in S. enterica isolates from informal markets in Cambodia, as well as support domestic epidemiological investigations of multidrug resistance (MDR) profiles.
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Affiliation(s)
- Carla L Schwan
- Department of Animal Sciences and Industry, Food Science Institute, Kansas State University, Manhattan, KS, United States
| | - Sara Lomonaco
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, MD, United States
| | - Leonardo M Bastos
- Department of Agronomy, Kansas State University, Manhattan, KS, United States
| | - Peter W Cook
- Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Joshua Maher
- Department of Animal Sciences and Industry, Food Science Institute, Kansas State University, Manhattan, KS, United States
| | - Valentina Trinetta
- Department of Animal Sciences and Industry, Food Science Institute, Kansas State University, Manhattan, KS, United States
| | - Manreet Bhullar
- Department of Horticulture and Natural Resources, Kansas State University, Olathe, KS, United States
| | - Randall K Phebus
- Department of Animal Sciences and Industry, Food Science Institute, Kansas State University, Manhattan, KS, United States
| | - Sara Gragg
- Department of Animal Sciences and Industry, Food Science Institute, Kansas State University, Manhattan, KS, United States
| | - Justin Kastner
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Jessie L Vipham
- Department of Animal Sciences and Industry, Food Science Institute, Kansas State University, Manhattan, KS, United States
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80
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Zhang SP, Feng HZ, Wang Q, Quan SW, Yu XQ, Tao X, Wang Y, Guo DD, Peng L, Feng HY, He YX. Proteomic analysis reveals the mechanism of different environmental stress-induced tolerance of Pseudomonas aeruginosa to monochloramine disinfection. JOURNAL OF HAZARDOUS MATERIALS 2021; 417:126082. [PMID: 34020351 DOI: 10.1016/j.jhazmat.2021.126082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 06/12/2023]
Abstract
Although drinking water disinfection proved to be an effective strategy to eliminate many pathogens, bacteria can still show disinfection tolerance in drinking water distribution systems. To date, the molecular mechanisms on how environmental stress affects the tolerance of Pseudomonas aeruginosa to monochloramine are not well understood. Here, we investigated how three stress conditions, namely starvation, low temperature, and starvation combined with low temperature, affected the monochloramine tolerance of Pseudomonas aeruginosa, an opportunistic pathogen commonly found in drinking water distribution systems. All stress conditions significantly promoted monochloramine tolerance, among which starvation had the most drastic effects. Proteomic analyses suggested that the three conditions not only triggered a positive antioxidant defense against oxidative damages but also prepared the bacteria to employ a passive defense mechanism against disinfectants via dormancy. Moreover, the expression of antioxidant enzymes reached the maximum under the starvation condition and further low temperature treatment had little effect on bacterial response to oxidative stress. Instead, we found further treatment of the starved cells with low temperature decreased the osmotic stress response and the stringent response, which generally play pivotal roles in disinfection tolerance. Taken together, these findings shed light on how abiotic factors influence the bacterial disinfection tolerance and will aid design of efficient strategies to eliminate Pseudomonas aeruginosa from drinking water.
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Affiliation(s)
- Si-Ping Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Han-Zhong Feng
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Qian Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Shuo-Wei Quan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Xiao-Quan Yu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Xuanyu Tao
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Yong Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Ding-Ding Guo
- School of Pharmacy, Lanzhou University, Lanzhou 730000, PR China
| | - Liang Peng
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Hu-Yuan Feng
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China.
| | - Yong-Xing He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China.
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81
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Harshaw NS, Stella NA, Lehner KM, Romanowski EG, Kowalski RP, Shanks RMQ. Antibiotics Used in Empiric Treatment of Ocular Infections Trigger the Bacterial Rcs Stress Response System Independent of Antibiotic Susceptibility. Antibiotics (Basel) 2021; 10:antibiotics10091033. [PMID: 34572615 PMCID: PMC8470065 DOI: 10.3390/antibiotics10091033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 12/02/2022] Open
Abstract
The Rcs phosphorelay is a bacterial stress response system that responds to envelope stresses and in turn controls several virulence-associated pathways, including capsule, flagella, and toxin biosynthesis, of numerous bacterial species. The Rcs system also affects antibiotic tolerance, biofilm formation, and horizontal gene transfer. The Rcs system of the ocular bacterial pathogen Serratia marcescens was recently demonstrated to influence ocular pathogenesis in a rabbit model of keratitis, with Rcs-defective mutants causing greater pathology and Rcs-activated strains demonstrating reduced inflammation. The Rcs system is activated by a variety of insults, including β-lactam antibiotics and polymyxin B. In this study, we developed three luminescence-based transcriptional reporters for Rcs system activity and used them to test whether antibiotics used for empiric treatment of ocular infections influence Rcs system activity in a keratitis isolate of S. marcescens. These included antibiotics to which the bacteria were susceptible and resistant. Results indicate that cefazolin, ceftazidime, polymyxin B, and vancomycin activate the Rcs system to varying degrees in an RcsB-dependent manner, whereas ciprofloxacin and tobramycin activated the promoter fusions, but in an Rcs-independent manner. Although minimum inhibitory concentration (MIC) analysis demonstrated resistance of the test bacteria to polymyxin B and vancomycin, the Rcs system was activated by sub-inhibitory concentrations of these antibiotics. Together, these data indicate that a bacterial stress system that influences numerous pathogenic phenotypes and drug-tolerance is influenced by different classes of antibiotics despite the susceptibility status of the bacterium.
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82
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Peterson SB, Bertolli SK, Mougous JD. The Central Role of Interbacterial Antagonism in Bacterial Life. Curr Biol 2021; 30:R1203-R1214. [PMID: 33022265 DOI: 10.1016/j.cub.2020.06.103] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The study of bacteria interacting with their environment has historically centered on strategies for obtaining nutrients and resisting abiotic stresses. We argue this focus has deemphasized a third facet of bacterial life that is equally central to their existence: namely, the threat to survival posed by antagonizing bacteria. The diversity and ubiquity of interbacterial antagonism pathways is becoming increasingly apparent, and the insidious manner by which interbacterial toxins disarm their targets emphasizes the highly evolved nature of these processes. Studies examining the role of antagonism in natural communities reveal it can serve many functions, from facilitating colonization of naïve habitats to maintaining bacterial community stability. The pervasiveness of antagonistic pathways is necessarily matched by an equally extensive array of defense strategies. These overlap with well characterized, central stress response pathways, highlighting the contribution of bacterial interactions to shaping cell physiology. In this review, we build the case for the ubiquity and importance of interbacterial antagonism.
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Affiliation(s)
- S Brook Peterson
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Savannah K Bertolli
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Joseph D Mougous
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195, USA.
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83
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Kim K, Islam M, Jung HW, Lim D, Kim K, Lee SG, Park C, Lee JC, Shin M. ppGpp signaling plays a critical role in virulence of Acinetobacter baumannii. Virulence 2021; 12:2122-2132. [PMID: 34375563 PMCID: PMC8366539 DOI: 10.1080/21505594.2021.1961660] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acinetobacter baumannii, a major nosocomial pathogen, survives in diverse hospital environments, and its multidrug resistance is a major concern. The ppGpp-dependent stringent response mediates the reprogramming of genes with diverse functions in several bacteria. We investigated whether ppGpp is involved in A. baumannii’s pathogenesis by examining biofilm formation, surface motility, adhesion, invasion, and mouse infection studies. Transcriptome analysis of early stationary phase cultures revealed 498 differentially-expressed genes (≥ 2-fold change) in a ppGpp-deficient A. baumannii strain; 220 and 278 genes were up and downregulated, respectively. Csu operon expression, important in pilus biosynthesis during early biofilm formation, was significantly reduced in the ppGpp-deficient strain. Our findings suggest that ppGpp signaling influences A. baumannii biofilm formation, surface motility, adherence, and virulence. We showed the association between ppGpp and pathogenicity in A. baumannii for the first time; ppGpp may be a novel antivirulence target in A. baumannii.
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Affiliation(s)
- Kyeongmin Kim
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
| | - Maidul Islam
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
| | - Hye-Won Jung
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
| | - Daejin Lim
- Department of Microbiology, Chonnam National University Medical School, Gwangju South Korea
| | - Kwangsoo Kim
- Department of Microbiology, Chonnam National University Medical School, Gwangju South Korea
| | - Sung-Gwon Lee
- School of Biological Sciences and Technology, Chonnam National University, Gwangju South Korea
| | - Chungoo Park
- School of Biological Sciences and Technology, Chonnam National University, Gwangju South Korea
| | - Je Chul Lee
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
| | - Minsang Shin
- Department of Microbiology, School of Medicine, Kyungpook National University, Jung-gu, Daegu, South Korea
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84
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Genome-Scale Metabolic Models and Machine Learning Reveal Genetic Determinants of Antibiotic Resistance in Escherichia coli and Unravel the Underlying Metabolic Adaptation Mechanisms. mSystems 2021; 6:e0091320. [PMID: 34342537 PMCID: PMC8409726 DOI: 10.1128/msystems.00913-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Antimicrobial resistance (AMR) is becoming one of the largest threats to public health worldwide, with the opportunistic pathogen Escherichia coli playing a major role in the AMR global health crisis. Unravelling the complex interplay between drug resistance and metabolic rewiring is key to understand the ability of bacteria to adapt to new treatments and to the development of new effective solutions to combat resistant infections. We developed a computational pipeline that combines machine learning with genome-scale metabolic models (GSMs) to elucidate the systemic relationships between genetic determinants of resistance and metabolism beyond annotated drug resistance genes. Our approach was used to identify genetic determinants of 12 AMR profiles for the opportunistic pathogenic bacterium E. coli. Then, to interpret the large number of identified genetic determinants, we applied a constraint-based approach using the GSM to predict the effects of genetic changes on growth, metabolite yields, and reaction fluxes. Our computational platform leads to multiple results. First, our approach corroborates 225 known AMR-conferring genes, 35 of which are known for the specific antibiotic. Second, integration with the GSM predicted 20 top-ranked genetic determinants (including accA, metK, fabD, fabG, murG, lptG, mraY, folP, and glmM) essential for growth, while a further 17 top-ranked genetic determinants linked AMR to auxotrophic behavior. Third, clusters of AMR-conferring genes affecting similar metabolic processes are revealed, which strongly suggested that metabolic adaptations in cell wall, energy, iron and nucleotide metabolism are associated with AMR. The computational solution can be used to study other human and animal pathogens. IMPORTANCEEscherichia coli is a major public health concern given its increasing level of antibiotic resistance worldwide and extraordinary capacity to acquire and spread resistance via horizontal gene transfer with surrounding species and via mutations in its existing genome. E. coli also exhibits a large amount of metabolic pathway redundancy, which promotes resistance via metabolic adaptability. In this study, we developed a computational approach that integrates machine learning with metabolic modeling to understand the correlation between AMR and metabolic adaptation mechanisms in this model bacterium. Using our approach, we identified AMR genetic determinants associated with cell wall modifications for increased permeability, virulence factor manipulation of host immunity, reduction of oxidative stress toxicity, and changes to energy metabolism. Unravelling the complex interplay between antibiotic resistance and metabolic rewiring may open new opportunities to understand the ability of E. coli, and potentially of other human and animal pathogens, to adapt to new treatments.
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85
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Xu Q, Hu X, Wang Y. Alternatives to Conventional Antibiotic Therapy: Potential Therapeutic Strategies of Combating Antimicrobial-Resistance and Biofilm-Related Infections. Mol Biotechnol 2021; 63:1103-1124. [PMID: 34309796 DOI: 10.1007/s12033-021-00371-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/08/2021] [Indexed: 12/14/2022]
Abstract
Antibiotics have been denoted as the orthodox therapeutic agents for fighting bacteria-related infections in clinical practices for decades. Nevertheless, overuse of antibiotics has led to the upsurge of species with antimicrobial resistance (AMR) or multi-drug resistance. Bacteria can also grow into the biofilm, which accounts for at least two-thirds of infections. Distinct gene expression and self-produced heterogeneous hydrated extracellular polymeric substance matrix architecture of biofilm contribute to their tolerance and externally manifest as antibiotic resistance. In this review, the difficulties in combating biofilm formation and AMR are introduced, and novel alternatives to antibiotics such as metal nanoparticles and quaternary ammonium compounds, chitosan and its derivatives, antimicrobial peptides, stimuli-responsive materials, phage therapy and other therapeutic strategies, from compounds to hydrogel, from inorganic to biological, are discussed. We expect to provide useful information for the readers who are seeking for solutions to the problem of AMR and biofilm-related infections.
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Affiliation(s)
- Qian Xu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610065, Sichuan, People's Republic of China
| | - Xuefeng Hu
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610065, Sichuan, People's Republic of China.
| | - Yunbing Wang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610065, Sichuan, People's Republic of China.
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86
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Cardoza E, Singh H. C Group-Mediated Antibiotic Stress Mimics the Cold Shock Response. Curr Microbiol 2021; 78:3372-3380. [PMID: 34283283 DOI: 10.1007/s00284-021-02613-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 07/12/2021] [Indexed: 11/26/2022]
Abstract
A temperature downshift results in stabilized secondary structure formation in mRNA that halts translation to which Escherichia coli responds by synthesizing a set of proteins termed as cold shock proteins (Csps). To cope with the sudden temperature drop, gene expression patterns are reprogrammed to induce Csps at the cost of other proteins. Out of the nine homologous proteins in the CspA family, CspA, CspB, CspG, and CspI have major roles in protecting the cell under a cold shock. Additionally, a subset of Csps has conferred the organism an ability to adapt to various stresses along the lines of nutrient deprivation, oxidative, heat, acid, and antibiotic stresses. Stressors like C group translational inhibitors stall the translational apparatus and produce a response similar to that observed under a temperature downshift. Conditions set by the antibiotic therefore elicit a cold shock response and induce the major Csps, thereby pointing out to a common mechanism existing between the two. In the current review, we briefly describe the induction of E. coli Csps under an antibiotic stress acquired from data published previously and help establish the role of Csps in protecting the cell against the inducing agents and as a participant in the organisms' complex stress response network.
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Affiliation(s)
- Evieann Cardoza
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS Deemed to be University, Vile Parle (West), Mumbai, India
| | - Harinder Singh
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS Deemed to be University, Vile Parle (West), Mumbai, India.
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87
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Dörr T. Understanding tolerance to cell wall-active antibiotics. Ann N Y Acad Sci 2021; 1496:35-58. [PMID: 33274447 PMCID: PMC8359209 DOI: 10.1111/nyas.14541] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 12/19/2022]
Abstract
Antibiotic tolerance-the ability of bacteria to survive for an extended time in the presence of bactericidal antibiotics-is an understudied contributor to antibiotic treatment failure. Herein, I review the manifestations, mechanisms, and clinical relevance of tolerance to cell wall-active (CWA) antibiotics, one of the most important groups of antibiotics at the forefront of clinical use. I discuss definitions of tolerance and assays for tolerance detection, comprehensively discuss the mechanism of action of β-lactams and other CWA antibiotics, and then provide an overview of how cells mitigate the potentially lethal effects of CWA antibiotic-induced cell damage to become tolerant. Lastly, I discuss evidence for a role of CWA antibiotic tolerance in clinical antibiotic treatment failure.
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Affiliation(s)
- Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Department of Microbiology, and Cornell Institute of Host–Pathogen Interactions and DiseaseCornell UniversityIthacaNew York
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88
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Mutational Activation of Antibiotic-Resistant Mechanisms in the Absence of Major Drug Efflux Systems of Escherichia coli. J Bacteriol 2021; 203:e0010921. [PMID: 33972351 DOI: 10.1128/jb.00109-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mutations are one of the common means by which bacteria acquire resistance to antibiotics. In an Escherichia coli mutant lacking major antibiotic efflux pumps AcrAB and AcrEF, mutations can activate alternative pathways that lead to increased antibiotic resistance. In this work, we isolated and characterized compensatory mutations of this nature mapping in four different regulatory genes, baeS, crp, hns, and rpoB. The gain-of-function mutations in baeS constitutively activated the BaeSR two-component regulatory system to increase the expression of the MdtABC efflux pump. Missense or insertion mutations in crp and hns caused derepression of an operon coding for the MdtEF efflux pump. Interestingly, despite the dependence of rpoB missense mutations on MdtABC for their antibiotic resistance phenotype, neither the expression of the mdtABCD-baeSR operon nor that of other known antibiotic efflux pumps went up. Instead, the transcriptome sequencing (RNA-seq) data revealed a gene expression profile resembling that of a "stringent" RNA polymerase where protein and DNA biosynthesis pathways were downregulated but pathways to combat various stresses were upregulated. Some of these activated stress pathways are also controlled by the general stress sigma factor RpoS. The data presented here also show that compensatory mutations can act synergistically to further increase antibiotic resistance to a level similar to the efflux pump-proficient parental strain. Together, the findings highlight a remarkable genetic ability of bacteria to circumvent antibiotic assault, even in the absence of a major intrinsic antibiotic resistance mechanism. IMPORTANCE Antibiotic resistance among bacterial pathogens is a chronic health concern. Bacteria possess or acquire various mechanisms of antibiotic resistance, and chief among them is the ability to accumulate beneficial mutations that often alter antibiotic targets. Here, we explored E. coli's ability to amass mutations in a background devoid of a major constitutively expressed efflux pump and identified mutations in several regulatory genes that confer resistance by activating specific or pleiotropic mechanisms.
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89
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Lu HF, Tsai YC, Li LH, Lin YT, Yang TC. Role of AzoR, a LysR-type transcriptional regulator, in SmeVWX pump-mediated antibiotic resistance in Stenotrophomonas maltophilia. J Antimicrob Chemother 2021; 76:2285-2293. [PMID: 34151959 DOI: 10.1093/jac/dkab203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 05/24/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The SmeVWX efflux pump of Stenotrophomonas maltophilia contributes to menadione (MD) tolerance and resistance to chloramphenicol, quinolones and tetracycline. The components of the SmeVWX efflux pump are encoded by a five-gene operon, smeU1VWU2X. We have previously demonstrated that the smeU1VWU2X operon is intrinsically unexpressed and inducibly expressed by MD via a SoxR- and SmeRv-involved regulatory circuit in S. maltophilia KJ. We also inferred that there should be other regulator(s) involved in MD-mediated smeU1VWU2X expression in addition to SoxR and SmeRv. OBJECTIVES To identify novel regulator(s) involved in the regulation of MD-mediated smeU1VWU2X expression and elucidate the regulatory circuit. METHODS A possible regulator candidate involved in the regulation of MD-mediated smeU1VWU2X expression was identified by a homologue search using the helix-turn-helix domain of SmeRv as a query. Gene expression was assessed using the promoter-xylE transcriptional fusion assay and quantitative RT-PCR. The impact of the regulator on SmeVWX pump-mediated functions was investigated via mutant construction and functional tests (antibiotic susceptibility and MD tolerance). RESULTS AzoR (Smlt3089), a LysR-type transcriptional regulator, was investigated. In unstressed logarithmically grown cells, AzoR was abundantly expressed and functioned as a repressor, inhibiting the expression of the smeU1VWU2X operon. MD challenge attenuated azoR expression, thus derepressing the expression of the smeU1VWU2X operon in S. maltophilia KJ. AzoR down-regulation-mediated smeU1VWU2X expression was observed in quinolone-resistant and SmeVWX-overexpressing S. maltophilia clinical isolates. CONCLUSIONS AzoR negatively regulates the expression of the smeU1VWU2X operon and SmeVWX pump-mediated antibiotic resistance in S. maltophilia.
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Affiliation(s)
- Hsu-Feng Lu
- Department of Clinical Pathology, Cheng Hsin General Hospital, Taipei, Taiwan.,Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung, Taiwan
| | - Yu-Chieh Tsai
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Gastroenterology and Hepatology, Department of Internal Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Li-Hua Li
- Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,PhD Program in Medical Biotechnology, Taipei Medical University, Taipei, Taiwan
| | - Yi-Tsung Lin
- Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Tsuey-Ching Yang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
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90
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Speers AM, Reguera G. Competitive advantage of oxygen-tolerant bioanodes of Geobacter sulfurreducens in bioelectrochemical systems. Biofilm 2021; 3:100052. [PMID: 34222855 PMCID: PMC8242959 DOI: 10.1016/j.bioflm.2021.100052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 10/31/2022] Open
Abstract
Oxidative stress greatly limits current harvesting from anode biofilms in bioelectrochemical systems yet insufficient knowledge of the antioxidant responses of electricigens prevents optimization. Using Geobacter sulfurreducens PCA as a model electricigen, we demonstrated enhanced oxygen tolerance and reduced electron losses as the biofilms grew in height on the anode. To investigate the molecular basis of biofilm tolerance, we developed a genetic screening and isolated 11 oxygen-tolerant (oxt) strains from a library of transposon-insertion mutants. The aggregative properties of the oxt mutants promoted biofilm formation and oxygen tolerance. Yet, unlike the wild type, none of the mutants diverted respiratory electrons to oxygen. Most of the oxt mutations inactivated pathways for the detoxification of reactive oxygen species that could have triggered compensatory chronic responses to oxidative stress and inhibit aerobic respiration. One of the mutants (oxt10) also had a growth advantage with Fe(III) oxides and during the colonization of the anode electrode. The enhanced antioxidant response in this mutant reduced the system's start-up and promoted current harvesting from bioanodes even in the presence of oxygen. These results highlight a hitherto unknown role of oxidative stress responses in the stability and performance of current-harvesting biofilms of G. sulfurreducens and identify biological and engineering approaches to grow electroactive biofilms with the resilience needed for practical applications.
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Affiliation(s)
- Allison M Speers
- Department of Microbiology and Molecular Genetics, Michigan State University, USA
| | - Gemma Reguera
- Department of Microbiology and Molecular Genetics, Michigan State University, USA
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91
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Ilsan NA, Lee YJ, Kuo SC, Lee IH, Huang TW. Antimicrobial Resistance Mechanisms and Virulence of Colistin- and Carbapenem-Resistant Acinetobacter baumannii Isolated from a Teaching Hospital in Taiwan. Microorganisms 2021; 9:microorganisms9061295. [PMID: 34198665 PMCID: PMC8232278 DOI: 10.3390/microorganisms9061295] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 01/01/2023] Open
Abstract
Acinetobacter baumannii, a Gram-negative bacterium, is an important nosocomial pathogen. Colistin-resistant A. baumannii is becoming a new concern, since colistin is one of the last-line antibiotics for infections by carbapenem-resistant A. baumannii. From 452 carbapenem-resistant isolates collected in a teaching hospital in Taipei, Taiwan, we identified seven that were resistant to colistin. Carbapenem resistance in these isolates is attributed to the presence of carbapenemase gene blaOXA-23 in their genomes. Colistin resistance is presumably conferred by mutations in the sensor kinase domain of PmrB found in these isolates, which are known to result in modification of colistin target lipid A via the PmrB-PmrA-PmrC signal transduction pathway. Overexpression of pmrC, eptA, and naxD was observed in all seven isolates. Colistin resistance mediated by pmrB mutations has never been reported in Taiwan. One of the seven isolates contained three mutations in lpxD and exhibited an altered lipopolysaccharide profile, which may contribute to its colistin resistance. No significant difference in growth rates was observed between the isolates and the reference strain, suggesting no fitness cost of colistin resistance. Biofilm formation abilities of the isolates were lower than that of the reference. Interestingly, one of the isolates was heteroresistant to colistin. Four of the isolates were significantly more virulent to wax moth larvae than the reference.
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Affiliation(s)
- Noor Andryan Ilsan
- International Master/Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
| | - Yuarn-Jang Lee
- Department of Internal Medicine, Division of Infectious Diseases, Taipei Medical University Hospital, Taipei 11031, Taiwan;
- Department of Internal Medicine, Division of Infectious Diseases, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Shu-Chen Kuo
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan 35053, Taiwan;
| | - I-Hui Lee
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Tzu-Wen Huang
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
- Correspondence: ; Tel./Fax: +886-2-2736-1661 (ext. 3925); (ext. 3921)
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92
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Chauhan R, Azmi W, Bansal S, Goel G. Multivariate analysis of adaptive response to ferulic acid and p-coumaric acid after physiological stresses in Cronobacter sakazakii. J Appl Microbiol 2021; 131:3069-3080. [PMID: 34048109 DOI: 10.1111/jam.15164] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 05/15/2021] [Accepted: 05/23/2021] [Indexed: 11/28/2022]
Abstract
AIM The present study demonstrated the antimicrobial activity of ferulic acid and p-coumaric acid against unstressed and stressed (cold stressed, starved and desiccated) Cronobacter sakazakii in laboratory media (37°C) and reconstituted powdered infant formulation (PIF) with mild heat treatment (50°C). METHODS AND RESULTS Five phenolics, namely, quercetin, rutin, caffeic acid, ferulic acid and p-coumaric acid, were tested for antimicrobial activities against five strains of C. sakazakii either unstressed or stressed. Strain specific higher resistance to ferulic acid and p-coumaric acid was observed after stress adaptation in laboratory media. The effect of cross protection was validated using reconstituted PIF as delivery vehicle of selected compounds. Both p-coumaric acid and ferulic acid showed inhibition of C. sakazakii in a dose and time dependent manner as revealed by their viable cell counts. Principal component analysis revealed that the desiccated cells were more sensitive to phenolics in reconstituted PIF. CONCLUSIONS Only ferulic acid and p-coumaric acid showed marked antibacterial activity with minimum inhibitory concentration in the range of 2·5-5 mg ml-1 for unstressed C. sakazakii cells in tryptone soy broth. The maximum inhibition was achieved with 20 mg ml-1 of both the tested polyphenols in reconstituted PIF. Cold stress and starvation stress did not impart any protection nor increased the susceptibility of C. sakazakii, whereas desiccation resulted in increased susceptibility to phenolic compounds. SIGNIFICANCE AND IMPACT OF THE STUDY The results obtained in this study helps in understanding the effect of environmental stresses during processing on susceptibility of C. sakazakii to natural antimicrobial agents. Future transcriptomic studies and functional genetic studies are warranted to understand the strain specific stress responses for the development of better control methods possibly by using these natural antagonists.
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Affiliation(s)
- R Chauhan
- Department of Biotechnology, Himachal Pradesh University, Shimla, India
| | - W Azmi
- Department of Biotechnology, Himachal Pradesh University, Shimla, India
| | - S Bansal
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, India
| | - G Goel
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, India.,Department of Microbiology, School of Interdisciplinary and Applied Sciences, Central University of Haryana, Mahendergarh, India
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93
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Evaluation of a Biocide Used in the Biological Isolation and Containment Unit of a Veterinary Teaching Hospital. Antibiotics (Basel) 2021; 10:antibiotics10060639. [PMID: 34071748 PMCID: PMC8229411 DOI: 10.3390/antibiotics10060639] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 11/17/2022] Open
Abstract
Hospital-acquired infections (HAIs) are a rising problem worldwide, and the best way of coping with them is through infection tracking and surveillance systems, combined with prevention strategies, namely efficient disinfection protocols, that employ various biocides. However, increasing reports about reductions in biocide susceptibility and the development of cross-resistance to antimicrobials emphasize the need for identifying the factors influencing biocide efficiency. In this study, 29 bacterial isolates (n = 3 E. coli, n = 2 Pseudomonas spp., n = 23 Enterococcus spp., and n = 1 Staphylococcus pseudintermedius), obtained from environmental samples collected from the Biological Isolation and Containment Unit (BICU), of the Veterinary Teaching Hospital of the Faculty of Veterinary Medicine, University of Lisbon, were tested in order to determine their antimicrobial susceptibility to various antibiotics. Thirteen of these isolates were further selected in order to determine their antimicrobial susceptibility to Virkon™ S, with and without the presence of organic matter. Afterward, seven of these isolates were incubated in the presence of sub-lethal concentrations of this formulation and, subsequently, new susceptibility profiles were determined. Fourteen of the 29 isolates (48.3%) were classified as multidrug resistant, all previously identified as enterococci. Concerning Virkon™ S's susceptibility, the Minimal Bactericidal Concentration (MBC) of this biocide regarding all isolates was at least eight times lower than the concentration regularly used, when no organic matter was present. However, when organic matter was added, MBC values rose up to 23 times. After exposure to sub-lethal concentrations of Virkon™ S, four enterococci presented a phenotypical change regarding antimicrobial susceptibility towards gentamicin. Virkon™ S also resulted in higher MBC values, up to 1.5 times, in the presence of low concentrations of organic matter, but no rise in these values was observed in assays without interfering substance. Virkon™ S seemed to be an efficient formulation in eliminating all bacteria isolates isolated from the BICU. However, organic matter could represent a hindrance to this ability, which emphasizes the importance of sanitization before disinfection procedures. The changes seen in antimicrobial susceptibility could be explained by a general stress-induced response promoted by the sub-lethal levels of Virkon™ S. Additionally, when no organic matter was present, a decrease in susceptibility to this biocide seemed to be non-existent.
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94
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Bacterial Resistance to Antimicrobial Agents. Antibiotics (Basel) 2021; 10:antibiotics10050593. [PMID: 34067579 PMCID: PMC8157006 DOI: 10.3390/antibiotics10050593] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/26/2022] Open
Abstract
Bacterial pathogens as causative agents of infection constitute an alarming concern in the public health sector. In particular, bacteria with resistance to multiple antimicrobial agents can confound chemotherapeutic efficacy towards infectious diseases. Multidrug-resistant bacteria harbor various molecular and cellular mechanisms for antimicrobial resistance. These antimicrobial resistance mechanisms include active antimicrobial efflux, reduced drug entry into cells of pathogens, enzymatic metabolism of antimicrobial agents to inactive products, biofilm formation, altered drug targets, and protection of antimicrobial targets. These microbial systems represent suitable focuses for investigation to establish the means for their circumvention and to reestablish therapeutic effectiveness. This review briefly summarizes the various antimicrobial resistance mechanisms that are harbored within infectious bacteria.
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95
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Sheikh SW, Ali A, Ahsan A, Shakoor S, Shang F, Xue T. Insights into Emergence of Antibiotic Resistance in Acid-Adapted Enterohaemorrhagic Escherichia coli. Antibiotics (Basel) 2021; 10:522. [PMID: 34063307 PMCID: PMC8147483 DOI: 10.3390/antibiotics10050522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/15/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
The emergence of multidrug-resistant pathogens presents a global challenge for treating and preventing disease spread through zoonotic transmission. The water and foodborne Enterohaemorrhagic Escherichia coli (EHEC) are capable of causing intestinal and systemic diseases. The root cause of the emergence of these strains is their metabolic adaptation to environmental stressors, especially acidic pH. Acid treatment is desired to kill pathogens, but the protective mechanisms employed by EHECs cross-protect against antimicrobial peptides and thus facilitate opportunities for survival and pathogenesis. In this review, we have discussed the correlation between acid tolerance and antibiotic resistance, highlighting the identification of novel targets for potential production of antimicrobial therapeutics. We have also summarized the molecular mechanisms used by acid-adapted EHECs, such as the two-component response systems mediating structural modifications, competitive inhibition, and efflux activation that facilitate cross-protection against antimicrobial compounds. Moving beyond the descriptive studies, this review highlights low pH stress as an emerging player in the development of cross-protection against antimicrobial agents. We have also described potential gene targets for innovative therapeutic approaches to overcome the risk of multidrug-resistant diseases in healthcare and industry.
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Affiliation(s)
- Salma Waheed Sheikh
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
| | - Ahmad Ali
- School of Agronomy, Anhui Agricultural University, Hefei 230036, China;
| | - Asma Ahsan
- Faculty of Life Sciences, University of Central Punjab, Lahore 54000, Punjab, Pakistan;
| | - Sidra Shakoor
- Station de Neucfchateau, CIRAD, 97130 Sainte-Marie, Capesterre Belle Eau, Guadeloupe, France;
| | - Fei Shang
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
| | - Ting Xue
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
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96
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Aggarwal SD, Lloyd AJ, Yerneni SS, Narciso AR, Shepherd J, Roper DI, Dowson CG, Filipe SR, Hiller NL. A molecular link between cell wall biosynthesis, translation fidelity, and stringent response in Streptococcus pneumoniae. Proc Natl Acad Sci U S A 2021; 118:e2018089118. [PMID: 33785594 PMCID: PMC8040666 DOI: 10.1073/pnas.2018089118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Survival in the human host requires bacteria to respond to unfavorable conditions. In the important Gram-positive pathogen Streptococcus pneumoniae, cell wall biosynthesis proteins MurM and MurN are tRNA-dependent amino acyl transferases which lead to the production of branched muropeptides. We demonstrate that wild-type cells experience optimal growth under mildly acidic stressed conditions, but ΔmurMN strain displays growth arrest and extensive lysis. Furthermore, these stress conditions compromise the efficiency with which alanyl-tRNAAla synthetase can avoid noncognate mischarging of tRNAAla with serine, which is toxic to cells. The observed growth defects are rescued by inhibition of the stringent response pathway or by overexpression of the editing domain of alanyl-tRNAAla synthetase that enables detoxification of tRNA misacylation. Furthermore, MurM can incorporate seryl groups from mischarged Seryl-tRNAAlaUGC into cell wall precursors with exquisite specificity. We conclude that MurM contributes to the fidelity of translation control and modulates the stress response by decreasing the pool of mischarged tRNAs. Finally, we show that enhanced lysis of ΔmurMN pneumococci is caused by LytA, and the murMN operon influences macrophage phagocytosis in a LytA-dependent manner. Thus, MurMN attenuates stress responses with consequences for host-pathogen interactions. Our data suggest a causal link between misaminoacylated tRNA accumulation and activation of the stringent response. In order to prevent potential corruption of translation, consumption of seryl-tRNAAla by MurM may represent a first line of defense. When this mechanism is overwhelmed or absent (ΔmurMN), the stringent response shuts down translation to avoid toxic generation of mistranslated/misfolded proteins.
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Affiliation(s)
- Surya D Aggarwal
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Adrian J Lloyd
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom;
| | | | - Ana Rita Narciso
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 1099-085 Oeiras, Portugal
- Unidade de Ciências Biomoleculares Aplicadas (UCIBIO), Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-149 Caparica, Portugal
| | - Jennifer Shepherd
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - David I Roper
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Christopher G Dowson
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Sergio R Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 1099-085 Oeiras, Portugal;
- Unidade de Ciências Biomoleculares Aplicadas (UCIBIO), Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-149 Caparica, Portugal
| | - N Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213;
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97
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Huang Y, Smith W, Harwood C, Wipat A, Bacardit J. Computational Strategies for the Identification of a Transcriptional Biomarker Panel to Sense Cellular Growth States in Bacillus subtilis. SENSORS (BASEL, SWITZERLAND) 2021; 21:2436. [PMID: 33916259 PMCID: PMC8036383 DOI: 10.3390/s21072436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/29/2021] [Accepted: 03/30/2021] [Indexed: 01/08/2023]
Abstract
A goal of the biotechnology industry is to be able to recognise detrimental cellular states that may lead to suboptimal or anomalous growth in a bacterial population. Our current knowledge of how different environmental treatments modulate gene regulation and bring about physiology adaptations is limited, and hence it is difficult to determine the mechanisms that lead to their effects. Patterns of gene expression, revealed using technologies such as microarrays or RNA-seq, can provide useful biomarkers of different gene regulatory states indicative of a bacterium's physiological status. It is desirable to have only a few key genes as the biomarkers to reduce the costs of determining the transcriptional state by opening the way for methods such as quantitative RT-PCR and amplicon panels. In this paper, we used unsupervised machine learning to construct a transcriptional landscape model from condition-dependent transcriptome data, from which we have identified 10 clusters of samples with differentiated gene expression profiles and linked to different cellular growth states. Using an iterative feature elimination strategy, we identified a minimal panel of 10 biomarker genes that achieved 100% cross-validation accuracy in predicting the cluster assignment. Moreover, we designed and evaluated a variety of data processing strategies to ensure our methods were able to generate meaningful transcriptional landscape models, capturing relevant biological processes. Overall, the computational strategies introduced in this study facilitate the identification of a detailed set of relevant cellular growth states, and how to sense them using a reduced biomarker panel.
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Affiliation(s)
- Yiming Huang
- Interdisciplinary Computing and Complex BioSystems (ICOS) Group, School of Computing, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (Y.H.); (W.S.)
| | - Wendy Smith
- Interdisciplinary Computing and Complex BioSystems (ICOS) Group, School of Computing, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (Y.H.); (W.S.)
| | - Colin Harwood
- Centre for Bacterial Cell Biology, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK;
| | - Anil Wipat
- Interdisciplinary Computing and Complex BioSystems (ICOS) Group, School of Computing, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (Y.H.); (W.S.)
| | - Jaume Bacardit
- Interdisciplinary Computing and Complex BioSystems (ICOS) Group, School of Computing, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; (Y.H.); (W.S.)
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98
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Sinha AK, Winther KS. The RelA hydrolase domain acts as a molecular switch for (p)ppGpp synthesis. Commun Biol 2021; 4:434. [PMID: 33790389 PMCID: PMC8012599 DOI: 10.1038/s42003-021-01963-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 03/04/2021] [Indexed: 11/24/2022] Open
Abstract
Bacteria synthesize guanosine tetra- and penta phosphate (commonly referred to as (p)ppGpp) in response to environmental stresses. (p)ppGpp reprograms cell physiology and is essential for stress survival, virulence and antibiotic tolerance. Proteins of the RSH superfamily (RelA/SpoT Homologues) are ubiquitously distributed and hydrolyze or synthesize (p)ppGpp. Structural studies have suggested that the shift between hydrolysis and synthesis is governed by conformational antagonism between the two active sites in RSHs. RelA proteins of γ-proteobacteria exclusively synthesize (p)ppGpp and encode an inactive pseudo-hydrolase domain. Escherichia coli RelA synthesizes (p)ppGpp in response to amino acid starvation with cognate uncharged tRNA at the ribosomal A-site, however, mechanistic details to the regulation of the enzymatic activity remain elusive. Here, we show a role of the enzymatically inactive hydrolase domain in modulating the activity of the synthetase domain of RelA. Using mutagenesis screening and functional studies, we identify a loop region (residues 114–130) in the hydrolase domain, which controls the synthetase activity. We show that a synthetase-inactive loop mutant of RelA is not affected for tRNA binding, but binds the ribosome less efficiently than wild type RelA. Our data support the model that the hydrolase domain acts as a molecular switch to regulate the synthetase activity. Sinha and Winther show that the Escherichia coli RelA inactive hydrolase domain modulates the activity of the synthetase domain. RelA produces (p)ppGpp in γ-proteobacteria; using mutagenesis screening and functional studies, the authors demonstrate that the H loop region in the RelA hydrolase domain acts as a molecular switch to regulate the synthetase domain activity of the enzyme.
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Affiliation(s)
- Anurag Kumar Sinha
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.,National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
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99
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Outer Membrane Vesicles (OMVs) Produced by Gram-Negative Bacteria: Structure, Functions, Biogenesis, and Vaccine Application. BIOMED RESEARCH INTERNATIONAL 2021; 2021:1490732. [PMID: 33834062 PMCID: PMC8016564 DOI: 10.1155/2021/1490732] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 03/01/2021] [Accepted: 03/13/2021] [Indexed: 12/12/2022]
Abstract
Gram-negative bacteria produce outer membrane vesicles (OMVs) with 10 to 300 nm of diameter. The contribution of OMVs to bacterial pathogenesis is a topic of great interest, and their capacity to be combined with antigens impact in the future to the development of vaccines.
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100
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Pinilla CMB, Stincone P, Brandelli A. Proteomic analysis reveals differential responses of Listeria monocytogenes to free and nanoencapsulated nisin. Int J Food Microbiol 2021; 346:109170. [PMID: 33770680 DOI: 10.1016/j.ijfoodmicro.2021.109170] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/04/2021] [Accepted: 03/08/2021] [Indexed: 12/18/2022]
Abstract
The ability of Listeria monocytogenes grow on ready-to-eat food is a major concern in food safety. Natural antimicrobials, such as nisin, can be used to control this pathogen, but the increasing reports of nisin tolerance and resistance make necessary novel approaches to increase its effectiveness, such as encapsulation. The goal of this study was to investigate how L. monocytogenes ATCC7644 regulates and shapes its proteome in response to sublethal doses of nisin and nisin-loaded phosphatidylcholine liposomes (lipo-nisin), compared to untreated cells growing under optimal conditions. Total proteins were extracted from L. monocytogenes cells treated for 1 h with free and lipo-nisin. As result, of 803 proteins that were initially identified, 64 and 53 proteins were differentially upregulated and downregulated respectively, in the treatments with nisin and lipo-nisin. Changes of Listeria proteome in response to treatments containing nisin were mainly related to ATP-binding cassette (ABC) transporter systems, transmembrane proteins, RNA-binding proteins and diverse stress response proteins. Some of the proteins uniquely detected in samples treated with free nisin were the membrane proteins SecD, Lmo1539 and the YfhO enzyme, which are related to translocation of L. monocytogenes virulence factors, activation of the LiaR-mediated stress defense and glycosylation of wall teichoic acid, respectively. The L. monocytogenes treated with liposome encapsulated nisin showed no expression of some stress response factors as compared with the free nisin, suggesting a reduction of stress mediated response and production of nisin-resistance factors by exposure to encapsulated nisin.
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Affiliation(s)
| | - Paolo Stincone
- Laboratório de Bioquímica e Microbiologia Aplicada, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Adriano Brandelli
- Laboratório de Bioquímica e Microbiologia Aplicada, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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