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Talat D, Sumitomo T, Honda-Ogawa M, Takahara Y, Mori Y, Masaya Yamaguchi, Nakata M, Ibrahim MS, Kawabata S. Two-component regulatory system TCS08 of a serotype 4 strain in pneumococcal pneumonia pathogenesis. J Oral Biosci 2024; 66:567-574. [PMID: 38885903 DOI: 10.1016/j.job.2024.06.001] [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: 02/20/2024] [Revised: 06/04/2024] [Accepted: 06/06/2024] [Indexed: 06/20/2024]
Abstract
OBJECTIVES Streptococcus pneumoniae, a human respiratory pathogen, causes diseases with severe morbidity and mortality rates worldwide. The two-component regulatory system (TCS) is an important signaling pathway that enables regulation of gene expression in response to environmental cues, thereby allowing an organism to adapt to a variety of host niches. Here we examined the contribution of pneumococcal TCS08 to bacterial colonization, the development of pneumonia, and pulmonary dysfunction. METHODS We employed an hk08 knockout mutant (Δhk08) with a background of the TIGR4 wild-type (WT) strain to verify whether TCS08 is associated with bacterial colonization and the development of pneumonia in a murine infection model. To clarify the association of hk08 inactivation-induced phenotypic changes with their virulence, we examined pneumococcal capsule production, colony morphology, and surface-displayed protein profiles. RESULTS Pneumococcal TCS08 was involved in bacterial colonization in the respiratory tract. Interruption of the signaling pathway of TCS08 by hk08 inactivation impaired mouse survival and increased the bacterial burden within the respiratory tract. Furthermore, a histopathological examination revealed massive inflammatory cell infiltration, edema formation, and diffuse alveolar damage in the lung tissues of mice infected with Δhk08 versus the WT or complemented strain. Interestingly, virulence-associated phenotype changes, including capsule production, increased chain length, and surface-displayed protein profile, were observed in the Δhk08 strain. CONCLUSIONS The present findings indicate that TCS08 contributes to pneumococcal colonization and pulmonary dysfunction by assisting adaptation to the respiratory tract milieu, leading to the development of pneumonia.
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Affiliation(s)
- Dalia Talat
- Department of Microbiology, Osaka University Graduate School of Dentistry, Osaka, Japan; Department of Microbiology, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Tomoko Sumitomo
- Department of Microbiology, Osaka University Graduate School of Dentistry, Osaka, Japan; Department of Oral Microbiology, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan.
| | - Mariko Honda-Ogawa
- Department of Microbiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Yuki Takahara
- Department of Microbiology, Osaka University Graduate School of Dentistry, Osaka, Japan; Department of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Yasushi Mori
- Department of Microbiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Masaya Yamaguchi
- Department of Microbiology, Osaka University Graduate School of Dentistry, Osaka, Japan; Bioinformatics Research Unit, Osaka University Graduate School of Dentistry, Osaka, Japan; Bioinformatics Center, Research Institute for Microbial Diseases, Osaka University, Japan; Center for Infectious Diseases Education and Research, Osaka University, Japan
| | - Masanobu Nakata
- Department of Microbiology, Osaka University Graduate School of Dentistry, Osaka, Japan; Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Madiha S Ibrahim
- Department of Microbiology, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Shigetada Kawabata
- Department of Microbiology, Osaka University Graduate School of Dentistry, Osaka, Japan; Center for Infectious Diseases Education and Research, Osaka University, Japan.
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Kalladeen M, Cheddie P, Akpaka PE. Group A streptococcus isolated in Guyana with reduced susceptibility to β-lactam antibiotics. Access Microbiol 2024; 6:000746.v3. [PMID: 39045256 PMCID: PMC11261736 DOI: 10.1099/acmi.0.000746.v3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 04/30/2024] [Indexed: 07/25/2024] Open
Abstract
Introduction. Streptococcus pyogenes [group A streptococci (GAS)] is the causative agent of pharyngitis and various other syndromes involving cellulitis, streptococcal toxic shock syndrome (STSS), and necrotising fasciitis. Although the prevalence of GAS infections globally remains high, necessitating the widespread use of β-lactam antibiotics, GAS have remained largely susceptible to these agents. However, there have been several reports of GAS with reduced susceptibility harbouring mutations in genes for penicillin-binding proteins (PBPs). The objectives of this study were to examine the in vitro β-lactam susceptibility patterns of group A streptococci, determine the prevalence of drug resistance, and ascertain whether such resistance could be attributed to mutations in specific PBP genes. Methods. In this study, we sought to use Sanger sequencing to identify mutations in PBP genes of Streptococcus pyogenes isolated from patients that required inpatient and outpatient care that could confer reduced PBP affinity for penicillin and/or cephalosporin antibiotics. All isolates were screened for susceptibility to penicillin, amoxicillin, and cefazolin using E-test strips. Results. While there were no documented cases of reduced susceptibility to penicillin or amoxicillin, 13 isolates had reduced susceptibility to cefazolin. Examination of pbp1a by Sanger sequencing revealed several isolates with single amino acid substitutions, which could potentially reduce the affinity of PBP 1A for cefazolin and possibly other first-generation cephalosporins. Conclusion. Penicillin and penicillin-derived antibiotics remain effective treatment options for GAS infections, but active surveillance is needed to monitor for changes to susceptibility patterns against these and other antibiotics and understand the genetic mechanisms contributing to them.
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Affiliation(s)
- Melissa Kalladeen
- Department of Paraclinical Sciences, University of the West Indies, St Augustine, Trinidad and Tobago
| | - Paul Cheddie
- Department of Medical Laboratory Science, University of Guyana, Turkeyen, Guyana
| | - Patrick Eberechi Akpaka
- Department of Paraclinical Sciences, University of the West Indies, St Augustine, Trinidad and Tobago
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Hiller NL, Orihuela CJ. Biological puzzles solved by using Streptococcus pneumoniae: a historical review of the pneumococcal studies that have impacted medicine and shaped molecular bacteriology. J Bacteriol 2024; 206:e0005924. [PMID: 38809015 PMCID: PMC11332154 DOI: 10.1128/jb.00059-24] [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] [Indexed: 05/30/2024] Open
Abstract
The major human pathogen Streptococcus pneumoniae has been the subject of intensive clinical and basic scientific study for over 140 years. In multiple instances, these efforts have resulted in major breakthroughs in our understanding of basic biological principles as well as fundamental tenets of bacterial pathogenesis, immunology, vaccinology, and genetics. Discoveries made with S. pneumoniae have led to multiple major public health victories that have saved the lives of millions. Studies on S. pneumoniae continue today, where this bacterium is being used to dissect the impact of the host on disease processes, as a powerful cell biology model, and to better understand the consequence of human actions on commensal bacteria at the population level. Herein we review the major findings, i.e., puzzle pieces, made with S. pneumoniae and how, over the years, they have come together to shape our understanding of this bacterium's biology and the practice of medicine and modern molecular biology.
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Affiliation(s)
- N. Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Carlos J. Orihuela
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Lux J, Portmann H, Sánchez García L, Erhardt M, Holivololona L, Laloli L, Licheri MF, Gallay C, Hoepner R, Croucher NJ, Straume D, Veening JW, Dijkman R, Heller M, Grandgirard D, Leib SL, Hathaway LJ. Klebsiella pneumoniae peptide hijacks a Streptococcus pneumoniae permease to subvert pneumococcal growth and colonization. Commun Biol 2024; 7:425. [PMID: 38589539 PMCID: PMC11001997 DOI: 10.1038/s42003-024-06113-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/26/2024] [Indexed: 04/10/2024] Open
Abstract
Treatment of pneumococcal infections is limited by antibiotic resistance and exacerbation of disease by bacterial lysis releasing pneumolysin toxin and other inflammatory factors. We identified a previously uncharacterized peptide in the Klebsiella pneumoniae secretome, which enters Streptococcus pneumoniae via its AmiA-AliA/AliB permease. Subsequent downregulation of genes for amino acid biosynthesis and peptide uptake was associated with reduction of pneumococcal growth in defined medium and human cerebrospinal fluid, irregular cell shape, decreased chain length and decreased genetic transformation. The bacteriostatic effect was specific to S. pneumoniae and Streptococcus pseudopneumoniae with no effect on Streptococcus mitis, Haemophilus influenzae, Staphylococcus aureus or K. pneumoniae. Peptide sequence and length were crucial to growth suppression. The peptide reduced pneumococcal adherence to primary human airway epithelial cell cultures and colonization of rat nasopharynx, without toxicity. We identified a peptide with potential as a therapeutic for pneumococcal diseases suppressing growth of multiple clinical isolates, including antibiotic resistant strains, while avoiding bacterial lysis and dysbiosis.
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Affiliation(s)
- Janine Lux
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Hannah Portmann
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Lucía Sánchez García
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Maria Erhardt
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Lalaina Holivololona
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Laura Laloli
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Manon F Licheri
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Clement Gallay
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Robert Hoepner
- Department of Neurology, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Nicholas J Croucher
- MRC Centre for Global Infectious Disease Analysis, Sir Michael Uren Hub, White City Campus, Imperial College London, London, UK
| | - Daniel Straume
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430, Ås, Norway
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Ronald Dijkman
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Manfred Heller
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Denis Grandgirard
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Stephen L Leib
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Lucy J Hathaway
- Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland.
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Ayoola MB, Shack LA, Phanstiel O, Nanduri B. Impact of Difluoromethylornithine and AMXT 1501 on Gene Expression and Capsule Regulation in Streptococcus pneumoniae. Biomolecules 2024; 14:178. [PMID: 38397415 PMCID: PMC10887117 DOI: 10.3390/biom14020178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 01/27/2024] [Accepted: 01/31/2024] [Indexed: 02/25/2024] Open
Abstract
Streptococcus pneumoniae (Spn), a Gram-positive bacterium, poses a significant threat to human health, causing mild respiratory infections to severe invasive conditions. Despite the availability of vaccines, challenges persist due to serotype replacement and antibiotic resistance, emphasizing the need for alternative therapeutic strategies. This study explores the intriguing role of polyamines, ubiquitous, small organic cations, in modulating virulence factors, especially the capsule, a crucial determinant of Spn's pathogenicity. Using chemical inhibitors, difluoromethylornithine (DFMO) and AMXT 1501, this research unveils distinct regulatory effects on the gene expression of the Spn D39 serotype in response to altered polyamine homeostasis. DFMO inhibits polyamine biosynthesis, disrupting pathways associated with glucose import and the interconversion of sugars. In contrast, AMXT 1501, targeting polyamine transport, enhances the expression of polyamine and glucose biosynthesis genes, presenting a novel avenue for regulating the capsule independent of glucose availability. Despite ample glucose availability, AMXT 1501 treatment downregulates the glycolytic pathway, fatty acid synthesis, and ATP synthase, crucial for energy production, while upregulating two-component systems responsible for stress management. This suggests a potential shutdown of energy production and capsule biosynthesis, redirecting resources towards stress management. Following DFMO and AMXT 1501 treatments, countermeasures, such as upregulation of stress response genes and ribosomal protein, were observed but appear to be insufficient to overcome the deleterious effects on capsule production. This study highlights the complexity of polyamine-mediated regulation in S. pneumoniae, particularly capsule biosynthesis. Our findings offer valuable insights into potential therapeutic targets for modulating capsules in a polyamine-dependent manner, a promising avenue for intervention against S. pneumoniae infections.
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Affiliation(s)
- Moses B Ayoola
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Leslie A Shack
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Otto Phanstiel
- Department of Medical Education, College of Medicine, University of Central Florida, Orlando, FL 32826, USA
| | - Bindu Nanduri
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
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Gingras H, Peillard-Fiorente F, Godin C, Patron K, Leprohon P, Ouellette M. New Resistance Mutations Linked to Decreased Susceptibility to Solithromycin in Streptococcus pneumoniae Revealed by Chemogenomic Screens. Antimicrob Agents Chemother 2023; 67:e0039523. [PMID: 37409958 PMCID: PMC10433811 DOI: 10.1128/aac.00395-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/18/2023] [Indexed: 07/07/2023] Open
Abstract
Two strains of Streptococcus pneumoniae, one expressing the methyltransferase Erm(B) and the other negative for erm(B), were selected for solithromycin resistance in vitro either with direct drug selection or with chemical mutagenesis followed by drug selection. We obtained a series of mutants that we characterized by next-generation sequencing. We found mutations in various ribosomal proteins (L3, L4, L22, L32, and S4) and in the 23S rRNA. We also found mutations in subunits of the phosphate transporter, in the DEAD box helicase CshB, and in the erm(B)L leader peptide. All mutations were shown to decrease solithromycin susceptibility when transformed into sensitive isolates. Some of the genes derived from our in vitro screens were found to be mutated also in clinical isolates with decreased susceptibility to solithromycin. While many mutations were in coding sequences, some were found in regulatory regions. These included novel phenotypic mutations in the intergenic regions of the macrolide resistance locus mef(E)/mel and in the vicinity of the ribosome binding site of erm(B). Our screens highlighted that macrolide-resistant S. pneumoniae can easily acquire resistance to solithromycin, and they revealed many new phenotypic mutations.
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Affiliation(s)
- Hélène Gingras
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec, Canada
| | - Flora Peillard-Fiorente
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec, Canada
| | - Chantal Godin
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec, Canada
| | - Kevin Patron
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec, Canada
| | - Philippe Leprohon
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec, Canada
| | - Marc Ouellette
- Centre de Recherche en Infectiologie du Centre de Recherche du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec, Canada
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7
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Lohsen S, Stephens DS. Inducible Mega-Mediated Macrolide Resistance Confers Heteroresistance in Streptococcus pneumoniae. Antimicrob Agents Chemother 2023; 67:e0131922. [PMID: 36847556 PMCID: PMC10019249 DOI: 10.1128/aac.01319-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
In Streptococcus pneumoniae (Spn), the 5.4 to 5.5 kb Macrolide Genetic Assembly (Mega) encodes an efflux pump (Mef[E]) and a ribosomal protection protein (Mel) conferring antibiotic resistance to commonly used macrolides in clinical isolates. We found the macrolide-inducible Mega operon provides heteroresistance (more than 8-fold range in MICs) to 14- and 15-membered ring macrolides. Heteroresistance is commonly missed during traditional clinical resistance screens but is highly concerning as resistant subpopulations can persist despite treatment. Spn strains containing the Mega element were screened via Etesting and population analysis profiling (PAP). All Mega-containing Spn strains screened displayed heteroresistance by PAP. The heteroresistance phenotype was linked to the mRNA expression of the mef(E)/mel operon of the Mega element. Macrolide induction uniformly increased Mega operon mRNA expression across the population, and heteroresistance was eliminated. A deletion of the 5' regulatory region of the Mega operon results in a mutant deficient in induction as well as in heteroresistance. The mef(E)L leader peptide sequence of the 5' regulatory region was required for induction and heteroresistance. Treatment with a noninducing 16-membered ring macrolide antibiotic did not induce the mef(E)/mel operon or eliminate the heteroresistance phenotype. Thus, inducibility of the Mega element by 14- and 15-membered macrolides and heteroresistance are linked in Spn. The stochastic variation in mef(E)/mel expression in a Spn population containing Mega provides the basis for heteroresistance.
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Affiliation(s)
- Sarah Lohsen
- Departments of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - David S. Stephens
- Departments of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Departments of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
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Lu Y, Liu Y, Zhou C, Liu Y, Long Y, Lin D, Xiong R, Xiao Q, Huang B, Chen C. Quorum sensing regulates heteroresistance in Pseudomonas aeruginosa. Front Microbiol 2022; 13:1017707. [PMID: 36386621 PMCID: PMC9650436 DOI: 10.3389/fmicb.2022.1017707] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/07/2022] [Indexed: 10/29/2023] Open
Abstract
The prevalence and genetic mechanism of antibiotic heteroresistance (HR) have attracted significant research attention recently. However, non-genetic mechanism of HR has not been adequately explored. The present study aimed to evaluate the role of quorum sensing (QS), an important mechanism of behavioral coordination in different subpopulations and consequent heteroresistance. First, the prevalence of HR to 7 antibiotics was investigated in 170 clinical isolates of P. aeruginosa using population analysis profiles. The results showed that P. aeruginosa was significantly heteroresistant to meropenem (MEM), amikacin (AMK), ciprofloxacin (CIP), and ceftazidime (CAZ). The observed HR was correlated with down-regulation of QS associated genes lasI and rhlI. Further, loss-of-function analysis results showed that reduced expression of lasI and rhlI enhanced HR of P. aeruginosa to MEM, AMK, CIP, and CAZ. Conversely, overexpression of these genes or treatment with 3-oxo-C12-HSL/C4-HSL lowered HR of P. aeruginosa to the four antibiotics. Additionally, although downregulation of oprD and upregulation of efflux-associated genes was evident in heteroresistant subpopulations, their expression was not regulated by LasI and RhlI. Moreover, fitness cost measurements disclosed higher growth rates of PAO1ΔlasI and PAO1ΔrhlI in the presence of sub-MIC antibiotic as compared with that of wild-type PAO1. Our data suggest that under temporary antibiotic pressure, downregulation of QS might result in less fitness cost and promote HR of P. aeruginosa.
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Affiliation(s)
- Yang Lu
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, China
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yuyang Liu
- Department of Laboratory Medicine, Chengdu First People's Hospital, Chengdu, China
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Chenxu Zhou
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
- The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yaqin Liu
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, China
| | - Yifei Long
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Dongling Lin
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Rui Xiong
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Qian Xiao
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Bin Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Cha Chen
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
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Baaity Z, von Loewenich FD, Nagy E, Orosz L, Burián K, Somogyvári F, Sóki J. Phenotypic and Molecular Characterization of Carbapenem-Heteroresistant Bacteroides fragilis Strains. Antibiotics (Basel) 2022; 11:antibiotics11050590. [PMID: 35625234 PMCID: PMC9138018 DOI: 10.3390/antibiotics11050590] [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: 03/31/2022] [Revised: 04/15/2022] [Accepted: 04/20/2022] [Indexed: 12/29/2022] Open
Abstract
Carbapenem-resistant Bacteroides fragilis strains usually emerge by an insertion sequence (IS) jump into the upstream region of the cfiA carbapenemase gene. However, intermediate or fully resistant cfiA-positive strains also exist. These do not have such IS element activations, but usually have heterogeneous resistance (HR) phenotypes, as detected by a disc diffusion or gradient tests. Heteroresistance is a serious antibiotic resistance problem, whose molecular mechanisms are not fully understood. We aim to characterize HR and investigate diagnostic issues in the set of cfiA-positive B. fragilis strains using phenotypic and molecular methods. Of the phenotypic methods used, the population analysis profile (PAP) and area under curve (AUC) measurements were the best prognostic markers for HR. PAP AUC, imipenem agar dilution and imipenemase production corresponded well with each other. We also identified a saturation curve parameter (quasi-PAP curves), which correlated well with these phenotypic traits, implying that HR is a stochastic process. The genes, on a previously defined ‘cfiA element’, act in a complex manner to produce the HR phenotype, including a lysine-acetylating toxin and a lysine-rich peptide. Furthermore, imipenem HR is triggered by imipenem. The two parameters that most correlate with the others are imipenemase production and ‘GNAT’ expression, which prompted us to suspect that carbapenem heteroresistance of the B. fragilis strains is stochastically regulated and is mediated by the altered imipenemase production.
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Affiliation(s)
- Zain Baaity
- Institute of Medical Microbiology, Albert Szent-Györgyi Health Centre and School of Medicine, University of Szeged, H-6725 Szeged, Hungary; (Z.B.); (E.N.); (L.O.); (K.B.); (F.S.)
| | | | - Elisabeth Nagy
- Institute of Medical Microbiology, Albert Szent-Györgyi Health Centre and School of Medicine, University of Szeged, H-6725 Szeged, Hungary; (Z.B.); (E.N.); (L.O.); (K.B.); (F.S.)
| | - László Orosz
- Institute of Medical Microbiology, Albert Szent-Györgyi Health Centre and School of Medicine, University of Szeged, H-6725 Szeged, Hungary; (Z.B.); (E.N.); (L.O.); (K.B.); (F.S.)
| | - Katalin Burián
- Institute of Medical Microbiology, Albert Szent-Györgyi Health Centre and School of Medicine, University of Szeged, H-6725 Szeged, Hungary; (Z.B.); (E.N.); (L.O.); (K.B.); (F.S.)
| | - Ferenc Somogyvári
- Institute of Medical Microbiology, Albert Szent-Györgyi Health Centre and School of Medicine, University of Szeged, H-6725 Szeged, Hungary; (Z.B.); (E.N.); (L.O.); (K.B.); (F.S.)
| | - József Sóki
- Institute of Medical Microbiology, Albert Szent-Györgyi Health Centre and School of Medicine, University of Szeged, H-6725 Szeged, Hungary; (Z.B.); (E.N.); (L.O.); (K.B.); (F.S.)
- Correspondence: author:
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Chippalkatti R, Egger B, Suter B. Mms19 promotes spindle microtubule assembly in Drosophila neural stem cells. PLoS Genet 2020; 16:e1008913. [PMID: 33211700 PMCID: PMC7714366 DOI: 10.1371/journal.pgen.1008913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 12/03/2020] [Accepted: 10/13/2020] [Indexed: 01/27/2023] Open
Abstract
Mitotic divisions depend on the timely assembly and proper orientation of the mitotic spindle. Malfunctioning of these processes can considerably delay mitosis, thereby compromising tissue growth and homeostasis, and leading to chromosomal instability. Loss of functional Mms19 drastically affects the growth and development of mitotic tissues in Drosophila larvae and we now demonstrate that Mms19 is an important factor that promotes spindle and astral microtubule (MT) growth, and MT stability and bundling. Mms19 function is needed for the coordination of mitotic events and for the rapid progression through mitosis that is characteristic of neural stem cells. Surprisingly, Mms19 performs its mitotic activities through two different pathways. By stimulating the mitotic kinase cascade, it triggers the localization of the MT regulatory complex TACC/Msps (Transforming Acidic Coiled Coil/Minispindles, the homolog of human ch-TOG) to the centrosome. This activity of Mms19 can be rescued by stimulating the mitotic kinase cascade. However, other aspects of the Mms19 phenotypes cannot be rescued in this way, pointing to an additional mechanism of Mms19 action. We provide evidence that Mms19 binds directly to MTs and that this stimulates MT stability and bundling.
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Affiliation(s)
- Rohan Chippalkatti
- Cell Biology, University of Bern, Berne, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Berne, Switzerland
| | - Boris Egger
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Beat Suter
- Cell Biology, University of Bern, Berne, Switzerland
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11
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Mechanisms and clinical relevance of bacterial heteroresistance. Nat Rev Microbiol 2019; 17:479-496. [DOI: 10.1038/s41579-019-0218-1] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2019] [Indexed: 02/08/2023]
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12
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Müller J, Braga S, Heller M, Müller N. Resistance formation to nitro drugs in Giardia lamblia: No common markers identified by comparative proteomics. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2019; 9:112-119. [PMID: 30889439 PMCID: PMC6423486 DOI: 10.1016/j.ijpddr.2019.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/15/2019] [Accepted: 03/12/2019] [Indexed: 02/07/2023]
Abstract
In order to elucidate the question whether resistance to nitro drugs in G. lamblia is due to common resistance markers, trophozoites of three resistant G. lamblia strains, namely C4, 1062ID10, and 713M3 were grown in the presence of the two nitro drugs metronidazole and nitazoxanide and compared to their corresponding wild-types WBC6, 106, and 713 by mass spectometry shotgun analysis of their proteomes. Depending on the strain and the nitro drug, more than 200 to 500 differentially expressed proteins were identified, but there were no common patterns across strains and drugs. All resistant strains underwent antigenic variation with distinct surface antigens like variant surface proteins or cysteine rich proteins depending on strain and nitro compound. A closer look on enzymes involved in nitroreduction and detoxification of nitro radicals, NO or O2 suggested the existence of distinct strategies for each drug and each strain. Therefore, we conclude that resistance to nitro drugs in G. lamblia is not correlated with a specific pattern of differentially expressed proteins and therefore seems not to be the result of a directed process. Is resistance to nitro drugs in G. lamblia due to common resistance markers? Three resistant strains were grown in the presence of two nitro drugs separately and compared to wild-types by MS shotgun analysis. More than 200 to 500 differentially expressed proteins identified depending on strain and drug. No common patterns across strains and drugs. Strain specific antigenic variation and strategies linked to nitro reduction.
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Affiliation(s)
- Joachim Müller
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012, Berne, Switzerland.
| | - Sophie Braga
- Proteomics & Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Berne, Freiburgstrasse 15, CH-3010, Berne, Switzerland.
| | - Manfred Heller
- Proteomics & Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Berne, Freiburgstrasse 15, CH-3010, Berne, Switzerland.
| | - Norbert Müller
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012, Berne, Switzerland.
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13
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Allemann A, Kraemer JG, Korten I, Ramsey K, Casaulta C, Wüthrich D, Ramette A, Endimiani A, Latzin P, Hilty M. Nasal Resistome Development in Infants With Cystic Fibrosis in the First Year of Life. Front Microbiol 2019; 10:212. [PMID: 30863369 PMCID: PMC6399209 DOI: 10.3389/fmicb.2019.00212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 01/24/2019] [Indexed: 12/20/2022] Open
Abstract
Polymicrobial infections of the respiratory tract due to antibiotic resistant bacteria are a great concern in patients with cystic fibrosis (CF). We therefore aimed at establishing a functional metagenomic method to analyze the nasal resistome in infants with CF within the first year of life. We included samples from patients before antibiotic treatment, which allowed obtaining information regarding natural status of the resistome. In total, we analyzed 130 nasal swabs from 26 infants with CF and screened for β-lactams (ampicillin, amoxicillin-clavulanic acid, and cefuroxime) and other classes of antibiotic resistances (tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole). For 69 swabs (53% of total), we found at least one non-susceptible phenotype. Analyses of the inserts recovered from non-susceptible clones by nanopore MinION sequencing revealed a large reservoir of resistance genes including mobile elements within the antibiotic naïve samples. Comparing the data of the resistome with the microbiota composition showed that the bacterial phyla and operational taxonomic units (OTUs) of the microbiota rather than the antibiotic treatment were associated with the majority of non-susceptible phenotypes in the resistome. Future studies will reveal if characterization of the resistome can help in clinical decision-making in patients with CF.
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Affiliation(s)
- Aurélie Allemann
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Julia G Kraemer
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland.,Institute for Work and Health (IST), University of Lausanne and University of Geneva, Epalinges, Switzerland
| | - Insa Korten
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.,Division of Respiratory Medicine, Department of Paediatrics, Inselspital, University of Bern, Bern, Switzerland
| | - Kathryn Ramsey
- Division of Respiratory Medicine, Department of Paediatrics, Inselspital, University of Bern, Bern, Switzerland
| | - Carmen Casaulta
- Division of Respiratory Medicine, Department of Paediatrics, Inselspital, University of Bern, Bern, Switzerland
| | | | - Daniel Wüthrich
- Applied Microbiology Research Unit, Department of Biomedicine, University of Basel, Basel, Switzerland.,Division of Clinical Microbiology, University Hospital Basel, Basel, Switzerland
| | - Alban Ramette
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Andrea Endimiani
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Philipp Latzin
- Division of Respiratory Medicine, Department of Paediatrics, Inselspital, University of Bern, Bern, Switzerland
| | - Markus Hilty
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
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14
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Nasher F, Aguilar F, Aebi S, Hermans PWM, Heller M, Hathaway LJ. Peptide Ligands of AmiA, AliA, and AliB Proteins Determine Pneumococcal Phenotype. Front Microbiol 2018; 9:3013. [PMID: 30568648 PMCID: PMC6290326 DOI: 10.3389/fmicb.2018.03013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/21/2018] [Indexed: 12/13/2022] Open
Abstract
The Ami-AliA/AliB oligopeptide permease of Streptococcus pneumoniae has been suggested to play a role in environmental sensing and colonisation of the nasopharynx by this human bacterial pathogen by binding peptides derived from bacterial neighbours of other species in the microbiota. Here, we investigated the effects of the peptide ligands of the permease’s substrate binding proteins AmiA, AliA, and AliB on pneumococcal phenotype. AmiA and AliA ligands reduced pneumococcal growth, increased biofilm production and reduced capsule size. In contrast, AliB ligand increased growth and greatly increased bacterial chain length. A decrease in transformation rate was observed in response to all three peptides. Changes in protein expression were also observed, particularly those associated with metabolism and cell wall synthesis. Understanding interspecies bacterial communication and its effect on development of colonising versus invasive phenotypes has the potential to reveal new targets to tackle and prevent pneumococcal infections.
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Affiliation(s)
- Fauzy Nasher
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Fernando Aguilar
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Suzanne Aebi
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
| | - Peter W M Hermans
- Janssen Vaccines and Prevention, Leiden, Netherlands.,Julius Center, UMC Utrecht, Utrecht, Netherlands
| | - Manfred Heller
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Lucy J Hathaway
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Bern, Switzerland
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15
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Nasher F, Förster S, Yildirim EC, Grandgirard D, Leib SL, Heller M, Hathaway LJ. Foreign peptide triggers boost in pneumococcal metabolism and growth. BMC Microbiol 2018; 18:23. [PMID: 29580217 PMCID: PMC5870813 DOI: 10.1186/s12866-018-1167-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 03/15/2018] [Indexed: 01/19/2023] Open
Abstract
Background Nonencapsulated Streptococcus pneumoniae bacteria are successful colonizers of the human nasopharynx and often possess genes aliB-like ORF 1 and 2 in place of capsule genes. AliB-like ORF 2 binds peptide FPPQSV, found in Prevotella species, resulting in enhanced colonization. How this response is mediated is so far unknown. Results Here we show that the peptide increases expression of genes involved in release of host carbohydrates, carbohydrate uptake and carbohydrate metabolism. In particular, the peptide increased expression of 1,5-anhydro-D-fructose reductase, a metabolic enzyme of an alternative starch and glycogen degrading pathway found in many organisms, in both transcriptomic and proteomic data. The peptide enhanced pneumococcal growth giving a competitive advantage to a strain with aliB-like ORF 2, over its mutant lacking the gene. Possession of aliB-like ORF 2 did not affect release of inflammatory cytokine CXCL8 from epithelial cells in culture and the nonencapsulated wild type strain was not able to establish disease or inflammation in an infant rat model of meningitis. Conclusions We propose that AliB-like ORF 2 confers an advantage in colonization by enhancing carbohydrate metabolism resulting in a boost in growth. This may explain the widespread presence of aliB-like ORF 2 in the nonencapsulated pneumococcal population in the human nasopharynx. Electronic supplementary material The online version of this article (10.1186/s12866-018-1167-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fauzy Nasher
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3001, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Sunniva Förster
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3001, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.,Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Efe C Yildirim
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3001, Bern, Switzerland
| | - Denis Grandgirard
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3001, Bern, Switzerland
| | - Stephen L Leib
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3001, Bern, Switzerland
| | - Manfred Heller
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, CH-3010, Bern, Switzerland
| | - Lucy J Hathaway
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3001, Bern, Switzerland.
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16
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He J, Jia X, Yang S, Xu X, Sun K, Li C, Yang T, Zhang L. Heteroresistance to carbapenems in invasive Pseudomonas aeruginosa infections. Int J Antimicrob Agents 2017; 51:413-421. [PMID: 29127047 DOI: 10.1016/j.ijantimicag.2017.10.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 09/14/2017] [Accepted: 10/28/2017] [Indexed: 11/24/2022]
Abstract
Heteroresistance is common in a variety of microbes, however carbapenem heteroresistance among invasive Pseudomonas aeruginosa infections has not been thoroughly characterised to date. The objective of this study was to investigate the mechanisms, molecular epidemiology and risk factors for invasive carbapenem-heteroresistant P. aeruginosa (CHPA) infections between 2011 and 2015 in Chongqing, China. A significant increase in the rates of heteroresistance to imipenem and meropenem was observed during the study period. Mechanistic analysis revealed that efflux system overexpression and decreased OprD could have contributed to carbapenem heteroresistance in P. aeruginosa. It was also observed that all of the subpopulations produced enhanced levels of biofilm compared with their native strains. Moreover, previous carbapenem exposure was identified as a common independent risk factor for imipenem-heteroresistant (IPM-HR) and meropenem-heteroresistant (MEM-HR) isolates, but patients infected with MEM-HR isolates were at higher risk of poor outcomes than those with IPM-HR isolates. Most importantly, there was a remarkable increase in the prescription of carbapenems during the study period, which was demonstrated to correlate significantly with the quarterly increasing prevalence of IPM-HR and MEM-HR isolates, respectively. These findings show the necessity of routine detection of carbapenem-heteroresistant strains and that strict control of carbapenem use is critical to reduce CHPA infections in hospitalised patients.
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Affiliation(s)
- Jianchun He
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016, PR China
| | - Xiaojiong Jia
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016, PR China
| | - Shuangshuang Yang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016, PR China
| | - Xiuyu Xu
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016, PR China
| | - Kunling Sun
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016, PR China
| | - Congya Li
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016, PR China
| | - Tianxiang Yang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016, PR China
| | - Liping Zhang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016, PR China.
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17
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Calvez P, Breukink E, Roper DI, Dib M, Contreras-Martel C, Zapun A. Substitutions in PBP2b from β-Lactam-resistant Streptococcus pneumoniae Have Different Effects on Enzymatic Activity and Drug Reactivity. J Biol Chem 2017; 292:2854-2865. [PMID: 28062575 DOI: 10.1074/jbc.m116.764696] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/22/2016] [Indexed: 12/31/2022] Open
Abstract
Pneumococcus resists β-lactams by expressing variants of its target enzymes, the penicillin-binding proteins (PBPs), with many amino acid substitutions. Up to 10% of the sequence can be modified. These altered PBPs have a much reduced reactivity with the drugs but retain their physiological activity of cross-linking the peptidoglycan, the major constituent of the bacterial cell wall. However, because β-lactams are chemical and structural mimics of the natural substrate, resistance mediated by altered PBPs raises the following paradox: how PBPs that react poorly with the drugs maintain a sufficient level of activity with the physiological substrate. This question is addressed for the first time in this study, which compares the peptidoglycan cross-linking activity of PBP2b from susceptible and resistant strains with their inhibition by different β-lactams. Unexpectedly, the enzymatic activity of the variants did not correlate with their antibiotic reactivity. This finding indicates that some of the numerous amino acid substitutions were selected to restore a viable level of enzymatic activity by a compensatory molecular mechanism.
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Affiliation(s)
- Philippe Calvez
- From the Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Eefjan Breukink
- the Department of Chemical Biology and Organic Chemistry, Institute of Biomembranes, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht 3584 CH, The Netherlands, and
| | - David I Roper
- the School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Mélanie Dib
- From the Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Carlos Contreras-Martel
- From the Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - André Zapun
- From the Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France,
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18
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Zheng JJ, Sinha D, Wayne KJ, Winkler ME. Physiological Roles of the Dual Phosphate Transporter Systems in Low and High Phosphate Conditions and in Capsule Maintenance of Streptococcus pneumoniae D39. Front Cell Infect Microbiol 2016; 6:63. [PMID: 27379215 PMCID: PMC4913102 DOI: 10.3389/fcimb.2016.00063] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 05/27/2016] [Indexed: 12/28/2022] Open
Abstract
Unlike most bacteria, Streptococcus pneumoniae (pneumococcus) has two evolutionarily distinct ABC transporters (Pst1 and Pst2) for inorganic phosphate (Pi) uptake. The genes encoding a two-component regulator (PnpRS) are located immediately upstream of the pst1 operon. Both the pst1 and pst2 operons encode putative PhoU-family regulators (PhoU1 and PhoU2) at their ends. This study addresses why S. pneumoniae contains dual Pi uptake systems and the regulation and contribution of the Pst1 and Pst2 systems in conditions of high (mM) Pi amount and low (μM) Pi amount. We show that in unencapsulated mutants, both pst1 and pst2 can be deleted, and Pi is taken up by a third Na+/Pi co-transporter, designated as NptA. In contrast, either pst1 or pst2 is unexpectedly required for the growth of capsule producing strains. We used a combination of mutational analysis, transcript level determinations by qRT-PCR and RNA-Seq, assays for cellular PnpR~P amounts by SDS-PAGE, and pulse-Pi uptake experiments to study the regulation of Pi uptake. In high Pi medium, PhoU2 serves as the master negative regulator of Pst2 transporter function and PnpR~P levels (post-transcriptionally). ΔphoU2 mutants have high PnpR~P levels and induction of the pst1 operon, poor growth, and sensitivity to antibiotics, possibly due to high Pi accumulation. In low Pi medium, Pst2 is still active, but PnpR~P amount and pst1 operon levels increase. Together, these results support a model in which pneumococcus maintains high Pi transport in high and low Pi conditions that is required for optimal capsule biosynthesis.
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Affiliation(s)
- Jiaqi J Zheng
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
| | - Dhriti Sinha
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
| | - Kyle J Wayne
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
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19
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Silva A, Sousa AM, Alves D, Lourenço A, Pereira MO. Heteroresistance to colistin in Klebsiella pneumoniae is triggered by small colony variants sub-populations within biofilms. Pathog Dis 2016; 74:ftw036. [PMID: 27140200 DOI: 10.1093/femspd/ftw036] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2016] [Indexed: 01/29/2023] Open
Abstract
The emergence of Klebsiella pneumoniae multidrug-resistant strains paves the way to the re-introduction of colistin as a salvage therapy. However, recent planktonic studies have reported several cases of heteroresistance to this antimicrobial agent. The aim of this present work was to gain better understanding about the response of K. pneumoniae biofilms to colistin antibiotherapy and inspect the occurrence of heteroresistance in biofilm-derived cells. Biofilm formation and its susceptibility to colistin were evaluated through the determination of biofilm-cells viability. The profiling of planktonic and biofilm cell populations was conducted to assess the occurrence of heteroresistance. Colony morphology was further characterized in order to inspect the potential role of colistin in K. pneumoniae phenotypic differentiation. Results show that K. pneumoniae was susceptible to colistin in its planktonic form, but biofilms presented enhanced resistance. Population analysis profiles pointed out that K. pneumoniae manifest heteroresistance to colistin only when grown in biofilm arrangements, and it was possible to identify a resistant sub-population presenting a small colony morphology (diameter around 5 mm). To the best of our knowledge, this is the first report linking heteroresistance to biofilm formation and a morphological distinctive sub-population. Moreover, this is the first evidence that biofilm formation can trigger the emergence of heteroresistance in an apparently susceptible strain.
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Affiliation(s)
- Ana Silva
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Ana Margarida Sousa
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Diana Alves
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Anália Lourenço
- ESEI-Escuela Superior de Ingeniería Informática, Universidad de Vigo, Ourense, Spain CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Maria Olívia Pereira
- CEB-Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
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20
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Liu EYM, Chang JC, Lin JC, Chang FY, Fung CP. Important Mutations Contributing to High-Level Penicillin Resistance in Taiwan 19F-14, Taiwan 23F-15, and Spain 23F-1 of Streptococcus pneumoniae Isolated from Taiwan. Microb Drug Resist 2016; 22:646-654. [PMID: 27042760 DOI: 10.1089/mdr.2015.0261] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Penicillin-resistant Streptococcus pneumoniae is a serious concern worldwide. In this study, we analyzed the cause of β-lactam resistance in pandemic multidrug-resistant clones. A total of 41 penicillin-nonsusceptible clinical isolates were collected from 1996 to 2012. Sero- and molecular typing confirmed that these isolates were clonal types of Taiwan19F-14, Taiwan23F-15, and Spain23F-1. Sero-switching was found in four isolates. All isolates were multidrug resistant. Sequencing analysis of the penicillin binding proteins (PBPs) was performed on PBP1a, 2b, and 2x, and a large number of mutations were identified in comparing to clinical penicillin-susceptible isolates and the recipient strain R6 used for homologous recombination. The T451A substitution was the key amino acid in PBP2b that contributed to penicillin resistance. T338A in PBP2x played a role in resistance and reached the highest level of resistance when combined with other mutations in PBP2x. High-level penicillin resistance could not be obtained without the combination of mutations in PBP1a with PBP2b and 2x. The amino acid substitutions in PBP1a, 2b, and 2x were the crucial factors for β-lactam resistance.
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Affiliation(s)
- Esther Yip-Mei Liu
- 1 Institute of Clinical Medicine, School of Medicine, National Yang-Ming University , Taipei, Taiwan
| | - Jen-Chang Chang
- 2 Institute of Infectious Diseases and Vaccinology, National Health Research Institutes , Zhunan, Taiwan
| | - Jung-Chung Lin
- 3 Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center , Taipei, Taiwan
| | - Feng-Yee Chang
- 3 Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center , Taipei, Taiwan
| | - Chang-Phone Fung
- 1 Institute of Clinical Medicine, School of Medicine, National Yang-Ming University , Taipei, Taiwan .,4 Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital and National Yang-Ming University , Taipei, Taiwan
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21
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Raczynska KD, Ruepp MD, Brzek A, Reber S, Romeo V, Rindlisbacher B, Heller M, Szweykowska-Kulinska Z, Jarmolowski A, Schümperli D. FUS/TLS contributes to replication-dependent histone gene expression by interaction with U7 snRNPs and histone-specific transcription factors. Nucleic Acids Res 2015; 43:9711-28. [PMID: 26250115 PMCID: PMC4787759 DOI: 10.1093/nar/gkv794] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 07/26/2015] [Indexed: 12/13/2022] Open
Abstract
Replication-dependent histone genes are up-regulated during the G1/S phase transition to meet the requirement for histones to package the newly synthesized DNA. In mammalian cells, this increment is achieved by enhanced transcription and 3′ end processing. The non-polyadenylated histone mRNA 3′ ends are generated by a unique mechanism involving the U7 small ribonucleoprotein (U7 snRNP). By using affinity purification methods to enrich U7 snRNA, we identified FUS/TLS as a novel U7 snRNP interacting protein. Both U7 snRNA and histone transcripts can be precipitated by FUS antibodies predominantly in the S phase of the cell cycle. Moreover, FUS depletion leads to decreased levels of correctly processed histone mRNAs and increased levels of extended transcripts. Interestingly, FUS antibodies also co-immunoprecipitate histone transcriptional activator NPAT and transcriptional repressor hnRNP UL1 in different phases of the cell cycle. We further show that FUS binds to histone genes in S phase, promotes the recruitment of RNA polymerase II and is important for the activity of histone gene promoters. Thus, FUS may serve as a linking factor that positively regulates histone gene transcription and 3′ end processing by interacting with the U7 snRNP and other factors involved in replication-dependent histone gene expression.
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Affiliation(s)
- Katarzyna Dorota Raczynska
- Institute of Cell Biology, University of Bern, Bern, Switzerland Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Marc-David Ruepp
- Institute of Cell Biology, University of Bern, Bern, Switzerland Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Aleksandra Brzek
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Stefan Reber
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Valentina Romeo
- Institute of Cell Biology, University of Bern, Bern, Switzerland Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | | | - Manfred Heller
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Zofia Szweykowska-Kulinska
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Artur Jarmolowski
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
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22
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Abstract
"Heteroresistance" describes a phenomenon where subpopulations of seemingly isogenic bacteria exhibit a range of susceptibilities to a particular antibiotic. Unfortunately, a lack of standard methods to determine heteroresistance has led to inappropriate use of this term. Heteroresistance has been recognized since at least 1947 and occurs in Gram-positive and Gram-negative bacteria. Its clinical relevance may be considerable, since more resistant subpopulations may be selected during antimicrobial therapy. However, the use of nonstandard methods to define heteroresistance, which are costly and involve considerable labor and resources, precludes evaluating the clinical magnitude and severity of this phenomenon. We review the available literature on antibiotic heteroresistance and propose recommendations for definitions and determination criteria for heteroresistant bacteria. This will help in assessing the global clinical impact of heteroresistance and developing uniform guidelines for improved therapeutic outcomes.
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23
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Chervinets IV, Beliaeva EA, Ganina EB, Troshin AV, Chervinets AV. [Antagonism of lactobacilli, oral streptococci and staphylococci]. STOMATOLOGII︠A︡ 2015; 94:4-6. [PMID: 25909604 DOI: 10.17116/stomat20159414-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
From the oral cavity of healthy young people aged 18-22 years there were isolated 26 strains of lactobacilli, 28 streptococci, including the pathogenic and opportunistic strains, and 32 strains of staphylococci, 10 of which were methicillin-resistant S.aureus. Oral lactobacilli possessed by a high probiotic potential, showing high antagonism to methicillin-resistant staphylococci, pathogenic and opportunistic streptococci and enterococci. Oral lactobacilli showed medium and high adhesive activity that determines their high adaptive capacity. Staphylococci and streptococci in 90.3% of cases have not an antagonistic effect on lactobacilli. Isolated lactobacilli can be used as probiotic strains for oral administration.
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Affiliation(s)
- Iu V Chervinets
- Tverskaia gosudarstvennaia meditsinskaia akademiia Minzdrava Rossii, 170100, Tver'
| | - E A Beliaeva
- Tverskaia gosudarstvennaia meditsinskaia akademiia Minzdrava Rossii, 170100, Tver'
| | - E B Ganina
- Tverskaia gosudarstvennaia meditsinskaia akademiia Minzdrava Rossii, 170100, Tver'
| | - A V Troshin
- Tverskaia gosudarstvennaia meditsinskaia akademiia Minzdrava Rossii, 170100, Tver'
| | - A V Chervinets
- Tverskaia gosudarstvennaia meditsinskaia akademiia Minzdrava Rossii, 170100, Tver'
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