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Huang Y, Shen Q, Xu H, Huang L, Xiang S, Li P, Fan L, Xie J. Mycobacterium smegmatis MfpC is a GEF that regulates mfpA translationally to alter the fluoroquinolone efficacy. Commun Biol 2024; 7:1035. [PMID: 39179666 PMCID: PMC11343762 DOI: 10.1038/s42003-024-06737-x] [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: 01/30/2024] [Accepted: 08/14/2024] [Indexed: 08/26/2024] Open
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a serious threat to global public health. Fluoroquinolones (FQs) are effective against M. tuberculosis; however, resistant strains have limited their efficacy. Mycobacterium fluoroquinolone resistance protein A (MfpA) confers intrinsic resistance to FQs; however, its regulatory mechanisms remain largely unknown. Using M. smegmatis as a model, we investigated whether MfpC is necessary for FQ susceptibility. MfpC mutants were sensitive to moxifloxacin, indicating that MfpC is involved in FQ susceptibility. By testing the mfpC inactivation phenotype in different mutants and using mycobacterial protein fragment complementation, we demonstrated that the function of MfpC depends on its interactions with MfpB. Guanine nucleotide exchange assays and site-directed mutagenesis confirmed that MfpC acts as a guanine nucleotide exchange factor to regulate MfpB. We propose that MfpB influences MfpA at the translational level. In summary, we reveal the role of MfpC in regulating the function of MfpA in FQ resistance.
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Affiliation(s)
- Yu Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Qinglei Shen
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Hongxiang Xu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Lingxi Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Shasha Xiang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Peibo Li
- Chongqing Public Health Medical Center, Chongqing, China.
| | - Lin Fan
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai Key Laboratory of Tuberculosis, Shanghai, China.
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China.
- Chongqing Public Health Medical Center, Chongqing, China.
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Ćwiklińska-Jurkowska M, Paprocka R, Mwaura GM, Kutkowska J. Modeling of Effectiveness of N3-Substituted Amidrazone Derivatives as Potential Agents against Gram-Positive Bacteria. Molecules 2024; 29:2369. [PMID: 38792231 PMCID: PMC11124365 DOI: 10.3390/molecules29102369] [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: 04/08/2024] [Revised: 05/10/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
Prediction of the antibacterial activity of new chemical compounds is an important task, due to the growing problem of bacterial drug resistance. Generalized linear models (GLMs) were created using 85 amidrazone derivatives based on the results of antimicrobial activity tests, determined as the minimum inhibitory concentration (MIC) against Gram-positive bacteria: Staphylococcus aureus, Enterococcus faecalis, Micrococcus luteus, Nocardia corallina, and Mycobacterium smegmatis. For the analysis of compounds characterized by experimentally measured MIC values, we included physicochemical properties (e.g., molecular weight, number of hydrogen donors and acceptors, topological polar surface area, compound percentages of carbon, nitrogen, and oxygen, melting points, and lipophilicity) as potential predictors. The presence of R1 and R2 substituents, as well as interactions between melting temperature and R1 or R2 substituents, were also considered. The set of potential predictors also included possible biological effects (e.g., antibacterial, antituberculotic) of tested compounds calculated with the PASS (Prediction of Activity Spectra for Substances) program. Using GLMs with least absolute shrinkage and selection (LASSO), least-angle regression, and stepwise selection, statistically significant models with the optimal value of the adjusted determination coefficient and of seven fit criteria were chosen, e.g., Akaike's information criterion. The most often selected variables were as follows: molecular weight, PASS_antieczematic, PASS_anti-inflam, squared melting temperature, PASS_antitumor, and experimental lipophilicity. Additionally, relevant to the bacterial strain, the interactions between melting temperature and R1 or R2 substituents were selected, indicating that the relationship between MIC and melting temperature depends on the type of R1 or R2 substituent.
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Affiliation(s)
- Małgorzata Ćwiklińska-Jurkowska
- Department of Biostatistics and Theory of Biomedical Systems, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Jagiellońska Str. 15, 85-067 Bydgoszcz, Poland;
| | - Renata Paprocka
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Jurasza Str. 2, 85-089 Bydgoszcz, Poland
| | - Godwin Munroe Mwaura
- Department of Pharmaceutical Chemistry, Pharmaceutics and Pharmacognosy, Faculty of Health Sciences, University of Nairobi, KNH, Nairobi P.O. Box 2149-00202, Kenya
| | - Jolanta Kutkowska
- Department of Genetics and Microbiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka Str. 19, 20-033 Lublin, Poland
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3
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le Run E, Tettelin H, Holland SM, Zelazny AM. Evolution towards extremely high β-lactam resistance in Mycobacterium abscessus outbreak strains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.593223. [PMID: 38903073 PMCID: PMC11188095 DOI: 10.1101/2024.05.08.593223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Treatment of Mycobacterium abscessus pulmonary disease requires multiple antibiotics including intravenous β-lactams (e.g., imipenem, meropenem). M. abscessus produces a β-lactamase (BlaMab) that inactivates β-lactam drugs but less efficiently carbapenems. Due to intrinsic and acquired resistance in M. abscessus and poor clinical outcomes, it is critical to understand the development of antibiotic resistance both within the host and in the setting of outbreaks. We compared serial longitudinally collected M. abscessus subsp. massiliense isolates from the index case of a CF center outbreak and four outbreak-related strains. We found strikingly high imipenem resistance in the later patient isolates, including the outbreak strain (MIC >512 μg/ml). The phenomenon was recapitulated upon exposure of intracellular bacteria to imipenem. Addition of the β-lactamase inhibitor avibactam abrogated the resistant phenotype. Imipenem resistance was caused by an increase in β-lactamase activity and increased bla Mab mRNA level. Concurrent increase in transcription of preceding ppiA gene indicated upregulation of the entire operon in the resistant strains. Deletion of the porin mspA coincided with the first increase in MIC (from 8 to 32 μg/ml). A frameshift mutation in msp2 responsible for the rough colony morphology, and a SNP in ATP-dependent helicase hrpA co-occurred with the second increase in MIC (from 32 to 256 μg/ml). Increased BlaMab expression and enzymatic activity may have been due to altered regulation of the ppiA-bla Mab operon by the mutated HrpA alone, or in combination with other genes described above. This work supports using carbapenem/β-lactamase inhibitor combinations for treating M. abscessus, particularly imipenem resistant strains.
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Affiliation(s)
- Eva le Run
- Laboratory of Clinical Immunology and Microbiology (LCIM), Immunopathogenesis Section, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, USA
| | - Hervé Tettelin
- Institute for Genome Sciences, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Steven M. Holland
- Laboratory of Clinical Immunology and Microbiology (LCIM), Immunopathogenesis Section, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, USA
| | - Adrian M. Zelazny
- Microbiology Service, Department of Laboratory Medicine (DLM), Clinical Center, NIH, Bethesda, MD, USA
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Palande A, Patil S, Veeram A, Sahoo SS, Lodhiya T, Maurya P, Muralikrishnan B, Chugh J, Mukherjee R. Proteomic Analysis of the Mycobacterium tuberculosis Outer Membrane for Potential Implications in Uptake of Small Molecules. ACS Infect Dis 2024; 10:890-906. [PMID: 38400924 DOI: 10.1021/acsinfecdis.3c00517] [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: 02/26/2024]
Abstract
Increased resistance to current antimycobacterial agents and a potential bias toward relatively hydrophobic chemical entities highlight an urgent need to understand how current anti-TB drugs enter the tubercle bacilli. While inner membrane proteins are well-studied, how small molecules cross the impenetrable outer membrane remains unknown. Here, we employed mass spectrometry-based proteomics to show that octyl-β-d-glucopyranoside selectively extracts the outer membrane proteins of Mycobacterium tuberculosis. Differentially expressed proteins between nutrient-replete and nutrient-depleted conditions were enriched to identify proteins involved in nutrient uptake. We demonstrate cell surface localization of seven new proteins using immunofluorescence and show that overexpression of the proteins LpqY and ProX leads to hypersensitivity toward streptomycin, while overexpression of SubI, SpmT, and Rv2041 exhibited higher membrane permeability, assessed through an EtBr accumulation assay. Further, proton NMR metabolomics suggests the role of six outer membrane proteins in glycerol uptake. This study identifies several outer membrane proteins that are involved in the permeation of small hydrophilic molecules and are potential targets for enhancing the uptake and efficacy of anti-TB drugs.
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Affiliation(s)
- Aseem Palande
- Department of Biology, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
| | - Saniya Patil
- Department of Biology, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
| | - Anjali Veeram
- Department of Biology, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
| | - Soumya Swastik Sahoo
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Pune 411008, India
| | - Tejan Lodhiya
- Department of Biology, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
| | - Pankaj Maurya
- Department of Biology, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
| | - Balaji Muralikrishnan
- Department of Biology, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
| | - Jeetender Chugh
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Pune 411008, India
| | - Raju Mukherjee
- Department of Biology, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
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5
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Shallom SJ, Tettelin H, Chandrasekaran P, Park IK, Agrawal S, Arora K, Sadzewicz L, Milstone AM, Aitken ML, Brown-Elliott BA, Wallace RJ, Sampaio EP, Niederweis M, Olivier KN, Holland SM, Zelazny AM. Evolution of Mycobacterium abscessus in the human lung: Cumulative mutations and genomic rearrangement of porin genes in patient isolates. Virulence 2023; 14:2215602. [PMID: 37221835 PMCID: PMC10243398 DOI: 10.1080/21505594.2023.2215602] [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: 11/22/2022] [Accepted: 05/01/2023] [Indexed: 05/25/2023] Open
Abstract
BACKGROUND Mycobacterium abscessus subspecies massiliense (M. massiliense) is increasingly recognized as an emerging bacterial pathogen, particularly in cystic fibrosis (CF) patients and CF centres' respiratory outbreaks. We characterized genomic and phenotypic changes in 15 serial isolates from two CF patients (1S and 2B) with chronic pulmonary M. massiliense infection leading to death, as well as four isolates from a CF centre outbreak in which patient 2B was the index case. RESULTS Comparative genomic analysis revealed the mutations affecting growth rate, metabolism, transport, lipids (loss of glycopeptidolipids), antibiotic susceptibility (macrolides and aminoglycosides resistance), and virulence factors. Mutations in 23S rRNA, mmpL4, porin locus and tetR genes occurred in isolates from both CF patients. Interestingly, we identified two different spontaneous mutation events at the mycobacterial porin locus: a fusion of two tandem porin paralogs in patient 1S and a partial deletion of the first porin paralog in patient 2B. These genomic changes correlated with reduced porin protein expression, diminished 14C-glucose uptake, slower bacterial growth rates, and enhanced TNF-α induction in mycobacteria-infected THP-1 human cells. Porin gene complementation of porin mutants partly restored 14C-glucose uptake, growth rate and TNF-α levels to those of intact porin strains. CONCLUSIONS We hypothesize that specific mutations accumulated and maintained over time in M. massiliense, including mutations shared among transmissible strains, collectively lead to more virulent, host adapted lineages in CF patients and other susceptible hosts.
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Affiliation(s)
- Shamira J. Shallom
- Microbiology Service, Department of Laboratory Medicine (DLM), Clinical Center, NIH, Bethesda, MD, USA
| | - Hervé Tettelin
- Institute for Genome Sciences, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Prabha Chandrasekaran
- Laboratory of Clinical Infectious Diseases (LCID), National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, USA
| | - In Kwon Park
- Laboratory of Clinical Infectious Diseases (LCID), National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, USA
| | - Sonia Agrawal
- Institute for Genome Sciences, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kriti Arora
- Laboratory of Clinical Infectious Diseases (LCID), National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, USA
| | - Lisa Sadzewicz
- Institute for Genome Sciences, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Aaron M. Milstone
- Pediatric Infectious Diseases, Johns Hopkins University, Baltimore, MD, USA
| | - Moira L. Aitken
- Division of Pulmonary and Critical Care Medicine, University of Washington Medical Center, Seattle, WA, USA
| | | | - Richard J. Wallace
- Mycobacteria/Nocardia Laboratory, University of Texas Health Science Center, Tyler, TX, USA
| | - Elizabeth P. Sampaio
- Laboratory of Clinical Infectious Diseases (LCID), National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, USA
| | | | - Kenneth N. Olivier
- Laboratory of Chronic Airway Infection, Pulmonary Branch, National Heart Lung and Blood Institute (NHLBI), NIH, Bethesda, MD, USA
| | - Steven M. Holland
- Laboratory of Clinical Infectious Diseases (LCID), National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, MD, USA
| | - Adrian M. Zelazny
- Microbiology Service, Department of Laboratory Medicine (DLM), Clinical Center, NIH, Bethesda, MD, USA
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6
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Zhang C, Ouyang Q, Zhou X, Huang Y, Zeng Y, Deng L, Lin D, Zheng W. In vitro activity of tetracycline analogs against multidrug-resistant and extensive drug resistance clinical isolates of Mycobacterium tuberculosis. Tuberculosis (Edinb) 2023; 140:102336. [PMID: 36963294 DOI: 10.1016/j.tube.2023.102336] [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: 12/08/2022] [Revised: 02/27/2023] [Accepted: 03/10/2023] [Indexed: 03/13/2023]
Abstract
BACKGROUND Multidrug-resistant tuberculosis (MDR-TB) has become a big threaten to global health. The current strategy for treatment of MDR-TB and extensive drug resistant tuberculosis (XDR-TB) is with low efficacy and high side effect. While new drug is fundamental for cure MDR-TB, repurposing the Food and Drug Administration (FDA)-approved drugs represents an alternative soluation with less cost. METHODS The activity of 8 tetracycline-class antibiotics against mycobacterium tuberculosis (M.tb) were determined by Minimum Inhibitory Concentration (MIC) in vitro. A transposon M.smeg libraries was generated by using the Harm phage and then used to isolate the conditional growth mutants in doxycycline containing plate. Eleven mutants were isolated and genomic DNAs were extracted using the cetyltrimethyl ammonium bromide (CTAB) method and analyzed by whole genome sequencing. RESULTS We found that three of eight drugs efficiently inhibited mycobacteria growth under the peak plasma concentration in the human body. Further tests showed these three tetracycline analogs (demeclocycline, doxycycline and methacycline) had antimicrobial activity against seven clinical isolates, including MDR and XDR strains. Among them, Doxycycline had the lowest MICs in all mycobacteria strains tested in this study. By using a transposon library, we identify the insertion of transposon in two genes, porin and MshA, associatewith the resistant to doxycycline. CONCLUSIONS Our findings show that tetracycline analogs such as doxycycline, has bactericidal activity against not only drug sensitive M.tb, but also clinical MDR and XDR strains, provided proof of concept to repurpose doxycycline to fight MDR-TB and XDR-TB. Further investigations are warranted to clarify the underlying mechanism and optimize the strategy in combination with other anti-TB drugs.
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Affiliation(s)
- Chi Zhang
- Department of Laboratory Medicine, Shenzhen University General Hospital, Shenzhen University, Shenzhen, China
| | - Qi Ouyang
- Guangdong Key Lab of Regional Immunity and Diseases, Department of Pathogen Biology, Shenzhen University School of Medicine, Shenzhen University, Shenzhen, China
| | - Xianyuan Zhou
- Department of Laboratory Medicine, Shenzhen University General Hospital, Shenzhen University, Shenzhen, China
| | - Yingfeng Huang
- Department of Laboratory Medicine, Shenzhen University General Hospital, Shenzhen University, Shenzhen, China
| | - Yu Zeng
- Department of Laboratory Medicine, Shenzhen University General Hospital, Shenzhen University, Shenzhen, China
| | - Li Deng
- Department of Laboratory Medicine, Shenzhen University General Hospital, Shenzhen University, Shenzhen, China
| | - Dachuan Lin
- Guangdong Key Lab of Regional Immunity and Diseases, Department of Pathogen Biology, Shenzhen University School of Medicine, Shenzhen University, Shenzhen, China.
| | - Weidong Zheng
- Department of Laboratory Medicine, Shenzhen University General Hospital, Shenzhen University, Shenzhen, China.
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Huang Y, Yan S, Li Y, Ai X, Yu X, Ge Y, Lv X, Fan L, Xie J. Mycobacterium Fluoroquinolone Resistance Protein D (MfpD), a GTPase-Activating Protein of GTPase MfpB, Is Involved in Fluoroquinolones Potency. Microbiol Spectr 2022; 10:e0209822. [PMID: 36453945 PMCID: PMC9769811 DOI: 10.1128/spectrum.02098-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 11/03/2022] [Indexed: 12/05/2022] Open
Abstract
Tuberculosis (TB) caused by Mycobacterium tuberculosis infection remains one of the most serious global health problems. Fluoroquinolones (FQs) are an important component of drug regimens against multidrug-resistant tuberculosis, but challenged by the emergence of FQ-resistant strains. Mycobacterium fluoroquinolone resistance protein A (MfpA) is a pentapeptide protein that confers resistance to FQs. MfpA is the fifth gene in the mfp operon among most Mycobacterium, implying other mfp genes might regulate the activity of MfpA. To elucidate the function of this operon, we constructed deletion mutants and rescued strains and found that MfpD is a GTPase-activating protein (GAP) involved in FQs activity. We showed that the recombinant strains overexpressing mfpD became more sensitive to FQs, whereas an mfpD deletion mutant was more resistant to FQs. By using site-directed mutagenesis and mycobacterial protein fragment complementation, we genetically demonstrated that mfpD participated in FQs susceptibility via directly acting on mfpB. We further biochemically demonstrated that MfpD was a GAP capable of stimulating the GTPase activity of MfpB. Our studies suggest that MfpD, a GAP of MfpB, is involved in MfpA-mediated FQs resistance. The function of MfpD adds new insights into the role of the mfp operon in Mycobacterium fluoroquinolone resistance. IMPORTANCE Tuberculosis is one of the leading causes of morbidity and mortality worldwide largely due to increasingly prevalent drug-resistant strains. Fluoroquinolones are important antibiotics used for treating multidrug-resistant tuberculosis (MDR-TB). The resistance mechanism mediated by the Mycobacterium fluoroquinolone resistance protein (MfpA) is unique in Mycobacterium. However, the regulatory mechanism of MfpA remains largely unclear. In this study, we first report that MfpD acts as a GAP for MfpB and characterize a novel pathway that controls Mycobacterium small G proteins. Our findings provide new insights into the regulation of MfpA and inspiration for new candidate targets for the discovery and development of anti-TB drugs.
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Affiliation(s)
- Yu Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-Environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Shuangquan Yan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-Environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Yuzhu Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-Environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Xuefeng Ai
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-Environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Xi Yu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-Environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Yan Ge
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-Environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Xi Lv
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-Environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Lin Fan
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai Key Laboratory of Tuberculosis, Shanghai, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-Environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
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8
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Barnabas V, Kashyap A, Raja R, Newar K, Rai D, Dixit NM, Mehra S. The Extent of Antimicrobial Resistance Due to Efflux Pump Regulation. ACS Infect Dis 2022; 8:2374-2388. [PMID: 36264222 DOI: 10.1021/acsinfecdis.2c00460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A key mechanism driving antimicrobial resistance (AMR) stems from the ability of bacteria to up-regulate efflux pumps upon exposure to drugs. The resistance gained by this up-regulation is pliable because of the tight regulation of efflux pump levels. This leads to temporary enhancement in survivability of bacteria due to higher efflux pump levels in the presence of antibiotics, which can be reversed when the cells are no longer exposed to the drug. Knowledge of the extent of resistance thus gained would inform intervention strategies aimed at mitigating AMR. Here, we combine mathematical modeling and experiments to quantify the maximum extent of resistance that efflux pump up-regulation can confer via phenotypic induction in the presence of drugs and genotypic abrogation of regulation. Our model describes the dynamics of drug transport in and out of cells coupled with the associated regulation of efflux pump levels and predicts the increase in the minimum inhibitory concentration (MIC) of drugs due to such regulation. To test the model, we measured the uptake and efflux as well as the MIC of the compound ethidium bromide (EtBr), a substrate of the efflux pump LfrA, in wild-type Mycobacterium smegmatis mc2155, as well as in two laboratory-generated strains. Our model captured the observed EtBr levels and MIC fold-changes quantitatively. Further, the model identified key parameters associated with the resulting resistance, variations in which could underlie the extent to which such resistance arises across different drug-bacteria combinations, potentially offering tunable handles to optimize interventions aimed at minimizing AMR.
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Affiliation(s)
- Vinay Barnabas
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| | - Akanksha Kashyap
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| | - Rubesh Raja
- Department of Chemical Engineering, Indian Institute of Science, Bangalore560012, India
| | - Kapil Newar
- Department of Chemical Engineering, Indian Institute of Science, Bangalore560012, India
| | - Deepika Rai
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
| | - Narendra M Dixit
- Department of Chemical Engineering, Indian Institute of Science, Bangalore560012, India.,Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore560012, India
| | - Sarika Mehra
- Department of Chemical Engineering, Indian Institute of Technology, Mumbai400076, India
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ppe51 Variants Enable Growth of Mycobacterium tuberculosis at Acidic pH by Selectively Promoting Glycerol Uptake. J Bacteriol 2022; 204:e0021222. [PMID: 36226966 PMCID: PMC9664963 DOI: 10.1128/jb.00212-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In defined media supplemented with single carbon sources, Mycobacterium tuberculosis (Mtb) exhibits carbon source specific growth restriction. When supplied with glycerol as the sole carbon source at pH 5.7, Mtb establishes a metabolically active state of nonreplicating persistence known as acid growth arrest. We hypothesized that acid growth arrest on glycerol is not a metabolic restriction, but rather an adaptive response. To test this hypothesis, we selected for and identified several Mtb mutants that could grow under these restrictive conditions. All mutations were mapped to the ppe51 gene and resulted in variants with 3 different amino acid substitutions- S211R, E215K, and A228D. Expression of the ppe51 variants in Mtb promoted growth at acidic pH showing that the mutant alleles are sufficient to cause the dominant gain-of-function, Enhanced Acid Growth (EAG) phenotype. Testing growth on other single carbon sources showed the PPE51 variants specifically enhanced growth on glycerol, suggesting PPE51 plays a role in glycerol uptake. Using radiolabeled glycerol, enhanced glycerol uptake was observed in Mtb expressing the PPE51 (S211R) variant, with glycerol overaccumulation in triacylglycerol. Notably, the EAG phenotype is deleterious for growth in macrophages, where the mutants have selectively faster replication and reduced survival in activated macrophages compared to resting macrophages. Recombinant PPE51 protein exhibited differential thermostability in the wild type (WT) or S211R variants in the presence of glycerol, supporting the model that EAG substitutions alter PPE51-glycerol interactions. Together, these findings support that PPE51 variants selectively promote glycerol uptake and that slowed growth at acidic pH is an important adaptive mechanism required for macrophage pathogenesis. IMPORTANCE It is puzzling why Mycobacterium tuberculosis (Mtb) cannot grow on glycerol at acidic pH, as it has a carbon source and oxygen, everything it needs to grow. In this study, we found that Mtb limits uptake of glycerol at acidic pH to restrict its growth and that mutations in ppe51 promote uptake of glycerol at acidic pH and enable growth. That is, Mtb can grow well at acidic pH on glycerol, but has adapted instead to stop growth. Notably, ppe51 variants exhibit enhanced replication and reduced survival in activated macrophages, supporting a role for pH-dependent slowed growth during macrophage pathogenesis.
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10
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Adhikary A, Biswal S, Chatterjee D, Ghosh AS. A NiCoT family metal transporter of Mycobacterium tuberculosis (Rv2856/NicT) behaves as a drug efflux pump that facilitates cross-resistance to antibiotics. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36282241 DOI: 10.1099/mic.0.001260] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Metals often act as a facilitator in the proliferation and persistence of antibiotic resistance. Efflux pumps play key roles in the co-selection of metal and antibiotic resistance. Here, we report the ability of a putative nickel/cobalt transporter (NiCoT family), Rv2856 or NicT of Mycobacterium tuberculosis (Mtb), to transport metal and antibiotics and identified some key amino acid residues that are important for its function. Ectopic expression of NicT in Escherichia coli CS109 resulted in the increase of intracellular nickel uptake. Additionally, enhanced tolerance towards several antibiotics (norfloxacin, sparfloxacin, ofloxacin, gentamicin, nalidixic acid and isoniazid) was observed with NicT overexpression in E. coli and Mycobacterium smegmatis. A comparatively lower intracellular accumulation of norfloxacin upon NicT overexpression than that of the cells without NicT indicated the involvement of NicT in an active efflux process. Although expression of NicT did not alter the sensitivity towards kanamycin, doxycycline, tetracycline, apramycin, neomycin and ethambutol, the presence of a sub-inhibitory dose of Ni2+ resulted in the manifestation of low-level tolerance towards these drugs. Further, substitution of four residues (H77I, D82I, H83L and D227I) in the conserved regions of NicT by isoleucine and leucine resulted in reduced to nearly complete loss of the transport function for both metals and antimicrobials. Therefore, the study suggests that nickel transporter Rv2856/NicT may actively export different drugs and the presence of nickel might drive the cross-resistance to some of the antibiotics.
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Affiliation(s)
- Anwesha Adhikary
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
| | - Sarmistha Biswal
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
| | - Debasmita Chatterjee
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
| | - Anindya S Ghosh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
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11
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Acyldepsipeptide Analogues: A Future Generation Antibiotics for Tuberculosis Treatment. Pharmaceutics 2022; 14:pharmaceutics14091956. [PMID: 36145704 PMCID: PMC9502522 DOI: 10.3390/pharmaceutics14091956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 11/25/2022] Open
Abstract
Acyldepsipeptides (ADEPs) are a new class of emerging antimicrobial peptides (AMPs), which are currently explored for treatment of pathogenic infections, including tuberculosis (TB). These cyclic hydrophobic peptides have a unique bacterial target to the conventional anti-TB drugs, and present a therapeutic window to overcome Mycobacterium Tuberculosis (M. tb) drug resistance. ADEPs exerts their antibacterial activity on M. tb strains through activation of the protein homeostatic regulatory protease, the caseinolytic protease (ClpP1P2). ClpP1P2 is normally regulated and activated by the ClpP-ATPases to degrade misfolded and toxic peptides and/or short proteins. ADEPs bind and dysregulate all the homeostatic capabilities of ClpP1P2 while inducing non-selective proteolysis. The uncontrolled proteolysis leads to M. tb cell death within the host. ADEPs analogues that have been tested possess cytotoxicity and poor pharmacokinetic and pharmacodynamic properties. However, these can be improved by drug design techniques. Moreover, the use of nanomaterial in conjunction with ADEPs would yield effective synergistic effect. This new mode of action has potential to combat and eradicate the extensive multi-drug resistance (MDR) problem that is currently faced by the public health pertaining bacterial infections, especially TB.
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12
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Olivença F, Ferreira C, Nunes A, Silveiro C, Pimentel M, Gomes JP, Catalão MJ. Identification of drivers of mycobacterial resistance to peptidoglycan synthesis inhibitors. Front Microbiol 2022; 13:985871. [PMID: 36147841 PMCID: PMC9485614 DOI: 10.3389/fmicb.2022.985871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/02/2022] [Indexed: 11/13/2022] Open
Abstract
Beta-lactams have been excluded from tuberculosis therapy due to the intrinsic resistance of Mycobacterium tuberculosis (Mtb) to this antibiotic class, usually attributed to a potent beta-lactamase, BlaC, and to an unusually complex cell wall. In this pathogen, the peptidoglycan is cross-linked by penicillin-binding proteins (PBPs) and L,D-transpeptidases, the latter resistant to inhibition by most beta-lactams. However, recent studies have shown encouraging results of beta-lactam/beta-lactamase inhibitor combinations in clinical strains. Additional research on the mechanisms of action and resistance to these antibiotics and other inhibitors of peptidoglycan synthesis, such as the glycopeptides, is crucial to ascertain their place in alternative regimens against drug-resistant strains. Within this scope, we applied selective pressure to generate mutants resistant to amoxicillin, meropenem or vancomycin in Mtb H37Rv or Mycolicibacterium smegmatis (Msm) mc2-155. These were phenotypically characterized, and whole-genome sequencing was performed. Mutations in promising targets or orthologue genes were inspected in Mtb clinical strains to establish potential associations between altered susceptibility to beta-lactams and the presence of key genomic signatures. The obtained isolates had substantial increases in the minimum inhibitory concentration of the selection antibiotic, and beta-lactam cross-resistance was detected in Mtb. Mutations in L,D-transpeptidases and major PBPs, canonical targets, or BlaC were not found. The transcriptional regulator PhoP (Rv0757) emerged as a common denominator for Mtb resistance to both amoxicillin and meropenem, while Rv2864c, a lipoprotein with PBP activity, appears to be specifically involved in decreased susceptibility to the carbapenem. Nonetheless, the mutational pattern detected in meropenem-resistant mutants was different from the yielded by amoxicillin-or vancomycin-selected isolates, suggesting that distinct pathways may participate in increased resistance to peptidoglycan inhibitors, including at the level of beta-lactam subclasses. Cross-resistance between beta-lactams and antimycobacterials was mostly unnoticed, and Msm meropenem-resistant mutants from parental strains with previous resistance to isoniazid or ethambutol were isolated at a lower frequency. Although cell-associated nitrocefin hydrolysis was increased in some of the isolates, our findings suggest that traditional assumptions of Mtb resistance relying largely in beta-lactamase activity and impaired access of hydrophilic molecules through lipid-rich outer layers should be challenged. Moreover, the therapeutical potential of the identified Mtb targets should be explored.
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Affiliation(s)
- Francisco Olivença
- Faculty of Pharmacy, Research Institute for Medicines (iMed.ULisboa), Universidade de Lisboa, Lisbon, Portugal
| | - Cláudia Ferreira
- Faculty of Pharmacy, Research Institute for Medicines (iMed.ULisboa), Universidade de Lisboa, Lisbon, Portugal
| | - Alexandra Nunes
- Genomics and Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
- Faculty of Veterinary Medicine, Lusófona University, Lisbon, Portugal
| | - Cátia Silveiro
- Faculty of Pharmacy, Research Institute for Medicines (iMed.ULisboa), Universidade de Lisboa, Lisbon, Portugal
| | - Madalena Pimentel
- Faculty of Pharmacy, Research Institute for Medicines (iMed.ULisboa), Universidade de Lisboa, Lisbon, Portugal
| | - João Paulo Gomes
- Genomics and Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
- Faculty of Veterinary Medicine, Lusófona University, Lisbon, Portugal
| | - Maria João Catalão
- Faculty of Pharmacy, Research Institute for Medicines (iMed.ULisboa), Universidade de Lisboa, Lisbon, Portugal
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13
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A Comprehensive Review and Update on Epidemiology, Symptomatology and Management of Nontuberculous Mycobacteria (NTM). JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2022. [DOI: 10.22207/jpam.16.2.41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontuberculous mycobacteria (NTM) are free-living organisms ubiquitously present in the environment. In recent times, NTM gained much importance due to the increase in incidence globally. They are potential agents in causing both pulmonary and extrapulmonary infections in both immunocompromised and immunocompetent individuals. The problem arises when the possible NTM cases are misdiagnosed as drug-resistant tuberculosis (DR-TB). Hence, it is essential to correctly identify the NTMs causing disease due to two major reasons. One is to prevent clinicians from starting anti-tuberculous drugs and the other is that treatment regimen differs for certain NTM from tuberculosis. Apart from conventional methods like smear microscopy, culture, in the current era newer diagnostic modalities like matrix-assisted laser desorption of ionization-time of flight mass spectrometry (MALDI TOF MS), line probe assay, genomic sequencing, are used in referral laboratories which allows identification and speciation of the organism. A thorough literature search was done in PubMed, Google Scholar, Cochrane Library, Embase, Scopus on nontuberculous mycobacteria. The search keywords include nontuberculous mycobacteria, atypical mycobacteria, case reports, and original articles on NTM. In this review, we have summarised the current knowledge on epidemiology, pathogenesis, clinical features, and treatment of NTM.
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14
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Gough M, Singh DK, Moodley C, Niu T, Golden NA, Kaushal D, Mehra S. Peripheral Blood Markers Correlate with the Progression of Active Tuberculosis Relative to Latent Control of Mycobacterium tuberculosis Infection in Macaques. Pathogens 2022; 11:pathogens11050544. [PMID: 35631065 PMCID: PMC9146669 DOI: 10.3390/pathogens11050544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/23/2022] [Accepted: 04/26/2022] [Indexed: 01/08/2023] Open
Abstract
Despite a century of research into tuberculosis (TB), there is a dearth of reproducible, easily quantifiable, biomarkers that can predict disease onset and differentiate between host disease states. Due to the challenges associated with human sampling, nonhuman primates (NHPs) are utilized for recapitulating the closest possible modelling of human TB. To establish a predictive peripheral biomarker profile based on a larger cohort of rhesus macaques (RM), we analyzed results pertaining to peripheral blood serum chemistry and cell counts from RMs that were experimentally exposed to Mtb in our prior studies and characterized as having either developed active TB (ATB) disease or latent TB infection (LTBI). We compared lung CFU burdens and quantitative pathologies with a number of measurables in the peripheral blood. Based on our results, the investigations were then extended to the study of specific molecules and cells in the lung compartments of a subset of these animals and their immune responses. In addition to the elevated serum C-reactive protein (CRP) levels, frequently used to discern the level of Mtb infection in model systems, reduced serum albumin-to-globulin (A/G) ratios were also predictive of active TB disease. Furthermore, higher peripheral myeloid cell levels, particularly those of neutrophils, kynurenine-to-tryptophan ratio, an indicator of induced expression of the immunosuppressive molecule indoleamine dioxygenase, and an influx of myeloid cell populations could also efficiently discriminate between ATB and LTBI in experimentally infected macaques. These quantifiable correlates of disease were then used in conjunction with a regression-based analysis to predict bacterial load. Our results suggest a potential biomarker profile of TB disease in rhesus macaques, that could inform future NHP–TB research. Our results thus suggest that specific biomarkers may be developed from the myeloid subset of peripheral blood or plasma with the ability to discriminate between active and latent Mtb infection.
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Affiliation(s)
- Maya Gough
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (M.G.); (D.K.S.); (C.M.)
| | - Dhiraj K. Singh
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (M.G.); (D.K.S.); (C.M.)
| | - Chivonne Moodley
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (M.G.); (D.K.S.); (C.M.)
- Tulane University Health Science Center, New Orleans, LA 70112, USA
| | - Tianhua Niu
- Department of Biostatistics and Bioinformatics, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, USA;
| | - Nadia A. Golden
- Tulane National Primate Research Center, Covington, LA 70433, USA;
| | - Deepak Kaushal
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (M.G.); (D.K.S.); (C.M.)
- Correspondence: (D.K); (S.M.); Tel.: +210-258-9209 (D.K.); +210-258-9508 (S.M.)
| | - Smriti Mehra
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (M.G.); (D.K.S.); (C.M.)
- Correspondence: (D.K); (S.M.); Tel.: +210-258-9209 (D.K.); +210-258-9508 (S.M.)
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15
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Control of subunit stoichiometry in single-chain MspA nanopores. Biophys J 2022; 121:742-754. [PMID: 35101416 PMCID: PMC8943699 DOI: 10.1016/j.bpj.2022.01.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 12/18/2021] [Accepted: 01/25/2022] [Indexed: 11/21/2022] Open
Abstract
Transmembrane protein channels enable fast and highly sensitive detection of single molecules. Nanopore sequencing of DNA was achieved using an engineered Mycobacterium smegmatis porin A (MspA) in combination with a motor enzyme. Due to its favorable channel geometry, the octameric MspA pore exhibits the highest current level compared with other pore proteins. To date, MspA is the only protein nanopore with a published record of DNA sequencing. While widely used in commercial devices, nanopore sequencing of DNA suffers from significant base-calling errors due to stochastic events of the complex DNA-motor-pore combination and the contribution of up to five nucleotides to the signal at each position. Different mutations in specific subunits of a pore protein offer an enormous potential to improve nucleotide resolution and sequencing accuracy. However, individual subunits of MspA and other oligomeric protein pores are randomly assembled in vivo and in vitro, preventing the efficient production of designed pores with different subunit mutations. In this study, we converted octameric MspA into a single-chain pore by connecting eight subunits using peptide linkers. Lipid bilayer experiments demonstrated that single-chain MspA formed membrane-spanning channels and discriminated all four nucleotides identical to MspA produced from monomers in DNA hairpin experiments. Single-chain constructs comprising three, five, six, and seven connected subunits assembled to functional channels, demonstrating a remarkable plasticity of MspA to different subunit stoichiometries. Thus, single-chain MspA constitutes a new milestone in the optimization of MspA as a biosensor for DNA sequencing and many other applications by enabling the production of pores with distinct subunit mutations and pore diameters.
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16
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Nontuberculous Mycobacterial Resistance to Antibiotics and Disinfectants: Challenges Still Ahead. BIOMED RESEARCH INTERNATIONAL 2022; 2022:8168750. [PMID: 35257011 PMCID: PMC8898113 DOI: 10.1155/2022/8168750] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/21/2021] [Accepted: 02/16/2022] [Indexed: 12/11/2022]
Abstract
The mortality incidence from nontuberculous mycobacteria (NTM) infections has been steadily developing globally. These bacterial agents were once thought to be innocent environmental saprophytic that are only dangerous to patients with defective lungs or the immunosuppressed. Nevertheless, the emergence of highly resistant NTM to different antibiotics and disinfectants increased the importance of these agents in the health system. Currently, NTM frequently infect seemingly immunocompetent individuals at rising rates. This is of concern as the resistant NTM are difficult to control and treat. The details behind this NTM development are only beginning to be clarified. The current study will provide an overview of the most important NTM resistance mechanisms to not only antibiotics but also the most commonly used disinfectants. Such evaluations can open new doors to improving control strategies and reducing the risk of NTM infection. Moreover, further studies are crucial to uncover this association.
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17
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Lewin A, Kamal E, Semmler T, Winter K, Kaiser S, Schäfer H, Mao L, Eschenhagen P, Grehn C, Bender J, Schwarz C. Genetic diversification of persistent Mycobacterium abscessus within cystic fibrosis patients. Virulence 2021; 12:2415-2429. [PMID: 34546836 PMCID: PMC8526041 DOI: 10.1080/21505594.2021.1959808] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mycobacterium (M.) abscessus infections in Cystic Fibrosis (CF) patients cause a deterioration of lung function. Treatment of these multidrug-resistant pathogens is associated with severe side-effects, while frequently unsuccessful. Insight on M. abscessus genomic evolvement during chronic lung infection would be beneficial for improving treatment strategies. A longitudinal study enrolling 42 CF patients was performed at a CF center in Berlin, Germany, to elaborate phylogeny and genomic diversification of in-patient M. abscessus. Eleven of the 42 CF patients were infected with M. abscessus. Five of these 11 patients were infected with global human-transmissible M. abscessus cluster strains. Phylogenetic analysis of 88 genomes from isolates of the 11 patients excluded occurrence of M. abscessus transmission among members of the study group. Genome sequencing and variant analysis of 30 isolates from 11 serial respiratory samples collected over 4.5 years from a chronically infected patient demonstrated accumulation of gene mutations. In total, 53 genes exhibiting non-synonymous variations were identified. Enrichment analysis emphasized genes involved in synthesis of glycopeptidolipids, genes from the embABC (arabinosyltransferase) operon, betA (glucose-methanol-choline oxidoreductase) and choD (cholesterol oxidase). Genetic diversity evolved in a variety of virulence- and resistance-associated genes. The strategy of M. abscessus populations in chronic lung infection is not clonal expansion of dominant variants, but to sustain simultaneously a wide range of genetic variants facilitating adaptation of the population to changing living conditions in the lung. Genomic diversification during chronic infection requires increased attention when new control strategies against M. abscessus infections are explored.
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Affiliation(s)
- Astrid Lewin
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | - Elisabeth Kamal
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | - Torsten Semmler
- Unit NG 1 Microbial Genomics, Robert Koch Institute, Berlin, Germany
| | - Katja Winter
- Unit MF1 Bioinformatics, Robert Koch Institute, Berlin, Germany
| | - Sandra Kaiser
- Unit MF1 Bioinformatics, Robert Koch Institute, Berlin, Germany
| | - Hubert Schäfer
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany
| | - Lei Mao
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch Institute, Berlin, Germany.,Unit 31 Infectious Disease Data Science Unit, Robert Koch Institute, Berlin, Germany
| | - Patience Eschenhagen
- Klinikum Westbrandenburg, Campus Potsdam, Cystic Fibrosis Section, Potsdam, Germany.,Pediatric Respiratory Medicine, Immunology and Intensive Care Medicine, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Claudia Grehn
- Department of Pediatrics, Division of Pulmonology, Immunology and Intensive Care Medicine, Division of Cystic Fibrosis, Charité - Universitätsmedizin, Berlin, Germany
| | - Jennifer Bender
- Unit 13 Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany.,ECDC Fellowship Programme, Public Health Microbiology Path (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Solna, Sweden
| | - Carsten Schwarz
- Klinikum Westbrandenburg, Campus Potsdam, Cystic Fibrosis Section, Potsdam, Germany.,Pediatric Respiratory Medicine, Immunology and Intensive Care Medicine, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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18
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Gupta R, Al-Kharji NMSA, Alqurafi MA, Nguyen TQ, Chai W, Quan P, Malhotra R, Simcox BS, Mortimer P, Brammer Basta LA, Rohde KH, Buynak JD. Atypically Modified Carbapenem Antibiotics Display Improved Antimycobacterial Activity in the Absence of β-Lactamase Inhibitors. ACS Infect Dis 2021; 7:2425-2436. [PMID: 34191496 PMCID: PMC8369493 DOI: 10.1021/acsinfecdis.1c00185] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
![]()
Commercial carbapenem
antibiotics are being used to treat multidrug
resistant (MDR) and extensively drug resistant (XDR) tuberculosis.
Like other β-lactams, carbapenems are irreversible inhibitors
of serine d,d-transpeptidases involved in peptidoglycan biosynthesis.
In addition to d,d-transpeptidases, mycobacteria also utilize
nonhomologous cysteine l,d-transpeptidases (Ldts) to cross-link
the stem peptides of peptidoglycan, and carbapenems form long-lived
acyl-enzymes with Ldts. Commercial carbapenems are C2 modifications
of a common scaffold. This study describes the synthesis of a series
of atypical, C5α modifications of the carbapenem scaffold, microbiological
evaluation against Mycobacterium tuberculosis (Mtb) and the nontuberculous mycobacterial species, Mycobacterium abscessus (Mab), as well
as acylation of an important mycobacterial target Ldt, LdtMt2. In vitro evaluation of these C5α-modified
carbapenems revealed compounds with standalone (i.e., in the absence of a β-lactamase inhibitor) minimum inhibitory
concentrations (MICs) superior to meropenem-clavulanate for Mtb, and meropenem-avibactam for Mab. Time-kill
kinetics assays showed better killing (2–4 log decrease) of Mtb and Mab with lower concentrations of
compound 10a as compared to meropenem. Although susceptibility
of clinical isolates to meropenem varied by nearly 100-fold, 10a maintained excellent activity against all Mtb and Mab strains. High resolution mass spectrometry
revealed that 10a acylates LdtMt2 at a rate
comparable to meropenem, but subsequently undergoes an unprecedented
carbapenem fragmentation, leading to an acyl-enzyme with mass of Δm = +86 Da. Rationale for the divergence of the nonhydrolytic
fragmentation of the LdtMt2 acyl-enzymes is proposed. The
observed activity illustrates the potential of novel atypical carbapenems
as prospective candidates for treatment of Mtb and Mab infections.
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Affiliation(s)
- Rashmi Gupta
- Division of Immunity and Pathogenesis, College of Medicine, Burnett School of Biomedical Sciences, University of Central Florida, 6900 Lake Nona Blvd., Orlando, Florida 32827, United States
| | | | - Maha A. Alqurafi
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Thu Q. Nguyen
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Weirui Chai
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Pojun Quan
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Riya Malhotra
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Breven S. Simcox
- Division of Immunity and Pathogenesis, College of Medicine, Burnett School of Biomedical Sciences, University of Central Florida, 6900 Lake Nona Blvd., Orlando, Florida 32827, United States
| | - Phil Mortimer
- Department of Chemistry, Mass Spectrometry Facility, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Leighanne A. Brammer Basta
- Chemistry Department, United States Naval Academy, 572M Holloway Road, Annapolis, Maryland 21402, United States
| | - Kyle H. Rohde
- Division of Immunity and Pathogenesis, College of Medicine, Burnett School of Biomedical Sciences, University of Central Florida, 6900 Lake Nona Blvd., Orlando, Florida 32827, United States
| | - John D. Buynak
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
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19
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de Moura VCN, Verma D, Everall I, Brown KP, Belardinelli JM, Shanley C, Stapleton M, Parkhill J, Floto RA, Ordway DJ, Jackson M. Increased Virulence of Outer Membrane Porin Mutants of Mycobacterium abscessus. Front Microbiol 2021; 12:706207. [PMID: 34335541 PMCID: PMC8317493 DOI: 10.3389/fmicb.2021.706207] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/23/2021] [Indexed: 11/13/2022] Open
Abstract
Chronic pulmonary infections caused by non-tuberculous mycobacteria of the Mycobacterium abscessus complex (MABSC) are emerging as a global health problem and pose a threat to susceptible individuals with structural lung disease such as cystic fibrosis. The molecular mechanisms underlying the pathogenicity and intrinsic resistance of MABSC to antibiotics remain largely unknown. The involvement of Msp-type porins in the virulence and biocide resistance of some rapidly growing non-tuberculous mycobacteria and the finding of deletions and rearrangements in the porin genes of serially collected MABSC isolates from cystic fibrosis patients prompted us to investigate the contribution of these major surface proteins to MABSC infection. Inactivation by allelic replacement of the each of the two Msp-type porin genes of M. abscessus subsp. massiliense CIP108297, mmpA and mmpB, led to a marked increase in the virulence and pathogenicity of both mutants in murine macrophages and infected mice. Neither of the mutants were found to be significantly more resistant to antibiotics. These results suggest that adaptation to the host environment rather than antibiotic pressure is the key driver of the emergence of porin mutants during infection.
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Affiliation(s)
- Vinicius C N de Moura
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Deepshikha Verma
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Isobel Everall
- Molecular Immunity Unit, Medical Research Council (MRC)-Laboratory of Molecular Biology, University of Cambridge Department of Medicine, Cambridge, United Kingdom.,Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Karen P Brown
- Molecular Immunity Unit, Medical Research Council (MRC)-Laboratory of Molecular Biology, University of Cambridge Department of Medicine, Cambridge, United Kingdom.,Cambridge Centre for Lung Infection, Papworth Hospital, Cambridge, United Kingdom
| | - Juan M Belardinelli
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Crystal Shanley
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Megan Stapleton
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - R Andres Floto
- Molecular Immunity Unit, Medical Research Council (MRC)-Laboratory of Molecular Biology, University of Cambridge Department of Medicine, Cambridge, United Kingdom.,Cambridge Centre for Lung Infection, Papworth Hospital, Cambridge, United Kingdom
| | - Diane J Ordway
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
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20
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Rybenkov VV, Zgurskaya HI, Ganguly C, Leus IV, Zhang Z, Moniruzzaman M. The Whole Is Bigger than the Sum of Its Parts: Drug Transport in the Context of Two Membranes with Active Efflux. Chem Rev 2021; 121:5597-5631. [PMID: 33596653 PMCID: PMC8369882 DOI: 10.1021/acs.chemrev.0c01137] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell envelope plays a dual role in the life of bacteria by simultaneously protecting it from a hostile environment and facilitating access to beneficial molecules. At the heart of this ability lie the restrictive properties of the cellular membrane augmented by efflux transporters, which preclude intracellular penetration of most molecules except with the help of specialized uptake mediators. Recently, kinetic properties of the cell envelope came into focus driven on one hand by the urgent need in new antibiotics and, on the other hand, by experimental and theoretical advances in studies of transmembrane transport. A notable result from these studies is the development of a kinetic formalism that integrates the Michaelis-Menten behavior of individual transporters with transmembrane diffusion and offers a quantitative basis for the analysis of intracellular penetration of bioactive compounds. This review surveys key experimental and computational approaches to the investigation of transport by individual translocators and in whole cells, summarizes key findings from these studies and outlines implications for antibiotic discovery. Special emphasis is placed on Gram-negative bacteria, whose envelope contains two separate membranes. This feature sets these organisms apart from Gram-positive bacteria and eukaryotic cells by providing them with full benefits of the synergy between slow transmembrane diffusion and active efflux.
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Affiliation(s)
- Valentin V Rybenkov
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Chhandosee Ganguly
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Inga V Leus
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Zhen Zhang
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Mohammad Moniruzzaman
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
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21
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Jackson M, Stevens CM, Zhang L, Zgurskaya HI, Niederweis M. Transporters Involved in the Biogenesis and Functionalization of the Mycobacterial Cell Envelope. Chem Rev 2021; 121:5124-5157. [PMID: 33170669 PMCID: PMC8107195 DOI: 10.1021/acs.chemrev.0c00869] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The biology of mycobacteria is dominated by a complex cell envelope of unique composition and structure and of exceptionally low permeability. This cell envelope is the basis of many of the pathogenic features of mycobacteria and the site of susceptibility and resistance to many antibiotics and host defense mechanisms. This review is focused on the transporters that assemble and functionalize this complex structure. It highlights both the progress and the limits of our understanding of how (lipo)polysaccharides, (glyco)lipids, and other bacterial secretion products are translocated across the different layers of the cell envelope to their final extra-cytoplasmic location. It further describes some of the unique strategies evolved by mycobacteria to import nutrients and other products through this highly impermeable barrier.
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Affiliation(s)
- Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Casey M. Stevens
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK 73019, USA
| | - Lei Zhang
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
| | - Helen I. Zgurskaya
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK 73019, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
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22
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Simonson AW, Umstead TM, Lawanprasert A, Klein B, Almarzooqi S, Halstead ES, Medina SH. Extracellular matrix-inspired inhalable aerogels for rapid clearance of pulmonary tuberculosis. Biomaterials 2021; 273:120848. [PMID: 33915409 DOI: 10.1016/j.biomaterials.2021.120848] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 12/31/2022]
Abstract
Tuberculosis (TB) remains a leading cause of death from a single infectious agent, and limiting the spread of multidrug-resistant TB (MDR-TB) is now an urgent global health priority. Essential to the persistence of this disease is the ability of Mycobacterium tuberculosis (Mtb) to circumvent host defenses by infecting lung macrophages to create a cellular niche for its survival and proliferation. This has urged the development of new therapeutic strategies that act through mechanisms distinct from conventional antibiotics, and thus are effective against MDR bacteria, while being able to efficiently kill persister Mtb cells in infected host macrophages. Here, we report a new class of gel-like microparticle aerosols, or 'aerogels', designed to exploit metabolic vulnerabilities of Mtb pathogens and TB-infected macrophages to enable preferential delivery of synergistic peptide-antibiotic combinations for potent and rapid antitubercular therapy. This is achieved by formulating aerogels through the supramolecular assembly of a de novo designed anti-TB peptide and the extracellular matrix (ECM)-derived polysaccharide, hyaluronic acid (HA). Importantly, HA serves as a nutrient source for Mtb cells during tissue invasion and proliferation, and is recognized by CD44 receptors highly expressed on lung macrophages during TB infection. By exploiting this metabolic substrate for pathogen targeting, HA aerogels are shown to avidly bind and kill both drug-sensitive and drug-resistant mycobacteria, while being efficiently internalized into macrophage host cells in vitro and in vivo to clear Mtb persisters. This multifaceted bioactivity suggests aerogels may serve as a versatile inhalable platform upon which novel biomaterials-enabled therapeutics can be developed to rapidly clear pulmonary MDR-TB.
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Affiliation(s)
- Andrew W Simonson
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Todd M Umstead
- Department of Pediatrics, Penn State College of Medicine, Hershey, PA, 17033, USA; Pulmonary Immunology and Physiology Laboratory, Penn State College of Medicine, Hershey, PA, 17033, USA
| | - Atip Lawanprasert
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Bailey Klein
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Sarah Almarzooqi
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - E Scott Halstead
- Department of Pediatrics, Penn State College of Medicine, Hershey, PA, 17033, USA; Pulmonary Immunology and Physiology Laboratory, Penn State College of Medicine, Hershey, PA, 17033, USA
| | - Scott H Medina
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA; Huck Institutes of the Life Sciences, Penn State University, University Park, PA, 16802, USA.
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Saxena S, Spaink HP, Forn-Cuní G. Drug Resistance in Nontuberculous Mycobacteria: Mechanisms and Models. BIOLOGY 2021; 10:biology10020096. [PMID: 33573039 PMCID: PMC7911849 DOI: 10.3390/biology10020096] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 02/07/2023]
Abstract
The genus Mycobacteria comprises a multitude of species known to cause serious disease in humans, including Mycobacterium tuberculosis and M. leprae, the responsible agents for tuberculosis and leprosy, respectively. In addition, there is a worldwide spike in the number of infections caused by a mixed group of species such as the M. avium, M. abscessus and M. ulcerans complexes, collectively called nontuberculous mycobacteria (NTMs). The situation is forecasted to worsen because, like tuberculosis, NTMs either naturally possess or are developing high resistance against conventional antibiotics. It is, therefore, important to implement and develop models that allow us to effectively examine the fundamental questions of NTM virulence, as well as to apply them for the discovery of new and improved therapies. This literature review will focus on the known molecular mechanisms behind drug resistance in NTM and the current models that may be used to test new effective antimicrobial therapies.
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Pathogen-specific antimicrobials engineered de novo through membrane-protein biomimicry. Nat Biomed Eng 2021; 5:467-480. [PMID: 33390588 PMCID: PMC8131206 DOI: 10.1038/s41551-020-00665-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022]
Abstract
Precision antimicrobials aim to kill pathogens without damaging commensal bacteria in the host, and thus to cure disease without antibiotic-associated dysbiosis. Here, we report the de novo design of a synthetic host defence peptide that targets a specific pathogen by mimicking key molecular features of the pathogen’s channel-forming membrane proteins. By exploiting physical and structural vulnerabilities within the pathogen’s cellular envelope, we designed a peptide sequence that undergoes instructed tryptophan-zippered assembly within the mycolic-acid rich outer membrane of Mycobacterium tuberculosis (Mtb) to specifically kill the pathogen without collateral toxicity towards lung commensal bacteria or host tissue. These ‘mycomembrane-templated’ assemblies elicit rapid mycobactericidal activity, and enhance the potency of antibiotics by improving their otherwise poor diffusion across the rigid Mtb envelope with respect to agents that exploit transmembrane protein channels for antimycobacterial activity. This biomimetic strategy may aid the design of other narrow-spectrum antimicrobial peptides.
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25
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Fishbein SRS, Tomasi FG, Wolf ID, Dulberger CL, Wang A, Keshishian H, Wallace L, Carr SA, Ioerger TR, Rego EH, Rubin EJ. The conserved translation factor LepA is required for optimal synthesis of a porin family in Mycobacterium smegmatis. J Bacteriol 2020; 203:JB.00604-20. [PMID: 33361193 PMCID: PMC8095456 DOI: 10.1128/jb.00604-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/15/2020] [Indexed: 11/20/2022] Open
Abstract
The recalcitrance of mycobacteria to antibiotic therapy is in part due to its ability to build proteins into a multi-layer cell wall. Proper synthesis of both cell wall constituents and associated proteins is crucial to maintaining cell integrity, and intimately tied to antibiotic susceptibility. How mycobacteria properly synthesize the membrane-associated proteome, however, remains poorly understood. Recently, we found that loss of lepA in Mycobacterium smegmatis (Msm) altered tolerance to rifampin, a drug that targets a non-ribosomal cellular process. LepA is a ribosome-associated GTPase found in bacteria, mitochondria, and chloroplasts, yet its physiological contribution to cellular processes is not clear. To uncover the determinants of LepA-mediated drug tolerance, we characterized the whole-cell proteomes and transcriptomes of a lepA deletion mutant relative to strains with lepA We find that LepA is important for the steady-state abundance of a number of membrane-associated proteins, including an outer membrane porin, MspA, which is integral to nutrient uptake and drug susceptibility. Loss of LepA leads to a decreased amount of porin in the membrane which leads to the drug tolerance phenotype of the lepA mutant. In mycobacteria, the translation factor LepA modulates mycobacterial membrane homeostasis, which in turn affects antibiotic tolerance.ImportanceThe mycobacterial cell wall is a promising target for new antibiotics due to the abundance of important membrane-associated proteins. Defining mechanisms of synthesis of the membrane proteome will be critical to uncovering and validating drug targets. We found that LepA, a universally conserved translation factor, controls the synthesis of a number of major membrane proteins in M. smegmatis LepA primarily controls synthesis of the major porin MspA. Loss of LepA results in decreased permeability through the loss of this porin, including permeability to antibiotics like rifampin and vancomycin. In mycobacteria, regulation from the ribosome is critical for the maintenance of membrane homeostasis and, importantly, antibiotic susceptibility.
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Affiliation(s)
- Skye R S Fishbein
- Department of Immunology and Infectious Disease, Harvard TH Chan School of Public Health, Boston, Massachusetts, 02115, United States
| | - Francesca G Tomasi
- Department of Immunology and Infectious Disease, Harvard TH Chan School of Public Health, Boston, Massachusetts, 02115, United States
| | - Ian D Wolf
- Department of Immunology and Infectious Disease, Harvard TH Chan School of Public Health, Boston, Massachusetts, 02115, United States
| | - Charles L Dulberger
- Department of Immunology and Infectious Disease, Harvard TH Chan School of Public Health, Boston, Massachusetts, 02115, United States
| | - Albert Wang
- Department of Immunology and Infectious Disease, Harvard TH Chan School of Public Health, Boston, Massachusetts, 02115, United States
| | | | - Luke Wallace
- Broad Institute of MIT and Harvard, Cambridge, 02142, United States
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, 02142, United States
| | - Thomas R Ioerger
- Department of Computer Science and Engineering, Texas A&M University, Texas, 77843, United States
| | - E Hesper Rego
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, 06510, United States
| | - Eric J Rubin
- Department of Immunology and Infectious Disease, Harvard TH Chan School of Public Health, Boston, Massachusetts, 02115, United States
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26
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Goossens SN, Sampson SL, Van Rie A. Mechanisms of Drug-Induced Tolerance in Mycobacterium tuberculosis. Clin Microbiol Rev 2020; 34:e00141-20. [PMID: 33055230 PMCID: PMC7566895 DOI: 10.1128/cmr.00141-20] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Successful treatment of tuberculosis (TB) can be hampered by Mycobacterium tuberculosis populations that are temporarily able to survive antibiotic pressure in the absence of drug resistance-conferring mutations, a phenomenon termed drug tolerance. We summarize findings on M. tuberculosis tolerance published in the past 20 years. Key M. tuberculosis responses to drug pressure are reduced growth rates, metabolic shifting, and the promotion of efflux pump activity. Metabolic shifts upon drug pressure mainly occur in M. tuberculosis's lipid metabolism and redox homeostasis, with reduced tricarboxylic acid cycle activity in favor of lipid anabolism. Increased lipid anabolism plays a role in cell wall thickening, which reduces sensitivity to most TB drugs. In addition to these general mechanisms, drug-specific mechanisms have been described. Upon isoniazid exposure, M. tuberculosis reprograms several pathways associated with mycolic acid biosynthesis. Upon rifampicin exposure, M. tuberculosis upregulates the expression of its drug target rpoB Upon bedaquiline exposure, ATP synthesis is stimulated, and the transcription factors Rv0324 and Rv0880 are activated. A better understanding of M. tuberculosis's responses to drug pressure will be important for the development of novel agents that prevent the development of drug tolerance following treatment initiation. Such agents could then contribute to novel TB treatment-shortening strategies.
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Affiliation(s)
- Sander N Goossens
- Family Medicine and Population Health (FAMPOP), Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium
| | - Samantha L Sampson
- DSI/NRF Centre of Excellence for Biomedical Tuberculosis Research/SA MRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Annelies Van Rie
- Family Medicine and Population Health (FAMPOP), Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium
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27
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Cullings K, Stott MB, Marinkovich N, DeSimone J, Bhardwaj S. Phylum-level diversity of the microbiome of the extremophilic basidiomycete fungus Pisolithus arhizus (Scop.) Rauschert: An island of biodiversity in a thermal soil desert. Microbiologyopen 2020; 9:e1062. [PMID: 32478485 PMCID: PMC7424252 DOI: 10.1002/mbo3.1062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/28/2020] [Accepted: 04/30/2020] [Indexed: 11/16/2022] Open
Abstract
We used high‐throughput DNA sequencing methods combined with bio‐geochemical profiles to characterize the internal environment and community structure of the microbiome of the basidiomycete fungus Pisolithus arhizus (Scop.) Rauschert from soils within a geothermal feature of Yellowstone National Park. Pisolithus arhizus is unique in that it forms closed fruiting bodies that sequester visible sulfur within. Fourier transform infrared spectroscopy (FTIR) analysis demonstrates that the P. arhizus fruiting body also concentrates copper, manganese, nickel, and zinc and contains pure granular silica. Gas chromatography‐mass spectrometry (GC‐MS) analysis indicates an environment rich in hydrocarbons. Oxygen probe analysis reveals that zones of up to 4× atmospheric oxygen exist within nanometers of zones of near anoxia. Analysis of microbial community structure using high‐throughput DNA sequencing methods shows that the fruiting body supports a microbiome that reflects the physiochemical environment of the fruiting body. Diversity and richness measures indicate a microbiome that is significantly richer and more diverse than that of the soils in which P. arhizus grows. Further, P. arhizus sporocarps are enriched significantly in Proteobacteria (primarily Burkholderia) Gemmatimonadetes, Bacteroidetes, Verrucomicrobia, Nitrospirae, Elusimicrobia, and Latescibacteria (WS3) while soils are enriched in Actinobacteria (primarily Mycobacterium), Dormibacteraeota (AD3), and Eremiobacteraeota (WPS‐2). Finally, pairwise % similarity comparisons indicate that P. arhizus harbors two lineages that may represent new groups in the candidate phylum radiation (CPR). Together, these results demonstrate that P. arhizus provides a novel environment for microbiome studies and provides for interesting hypotheses regarding the evolution, origins, and functions of symbioses and novel microbes.
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Affiliation(s)
- Ken Cullings
- JQ Division, NASA-Ames Research Center, Moffett Field, California, USA
| | - Matthew B Stott
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | | | - Julia DeSimone
- JQ Division, NASA-Ames Research Center, Moffett Field, California, USA
| | - Shilpa Bhardwaj
- JQ Division, NASA-Ames Research Center, Moffett Field, California, USA
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28
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Veyron‐Churlet R, Saliou J, Locht C. Protein scaffold involving MSMEG_1285 maintains cell wall organization and mediates penicillin sensitivity in mycobacteria. FEBS J 2020; 287:4415-4426. [DOI: 10.1111/febs.15232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/06/2019] [Accepted: 01/27/2020] [Indexed: 12/29/2022]
Affiliation(s)
- Romain Veyron‐Churlet
- U1019 – UMR9017 – CIIL – Center for Infection and Immunity of Lille CNRS Inserm CHU Lille Institut Pasteur de Lille Université de Lille France
| | - Jean‐Michel Saliou
- U1019 – UMR9017 – CIIL – Center for Infection and Immunity of Lille CNRS Inserm CHU Lille Institut Pasteur de Lille Université de Lille France
| | - Camille Locht
- U1019 – UMR9017 – CIIL – Center for Infection and Immunity of Lille CNRS Inserm CHU Lille Institut Pasteur de Lille Université de Lille France
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29
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Xu S, Hou X, Sun L, Zhang J, Ji X, Wang X, Li H, Li Z. An immunoproteomic approach to identify antigenic proteins in Nocardia farcinica IFM 10152. Microb Pathog 2019; 137:103705. [PMID: 31487535 DOI: 10.1016/j.micpath.2019.103705] [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: 06/02/2019] [Revised: 08/22/2019] [Accepted: 09/01/2019] [Indexed: 02/07/2023]
Abstract
Nocardia farcinica is the etiological agent of nocardiosis, leading to serious pulmonary or systemic infections. To uncover virulence factors and early diagnostic markers, secreted proteins of N. farcinica IFM 10152 were analyzed using an immunoproteome-based approach. A total of 5 proteins were identified by matrix-assisted laser desorption (MALDI-TOF-MS). Bioinformatic analyses showed that the identified proteins were involved in defense against the host innate immune system and required for pathogenesis. All proteins were expressed in E. coli and antigenicity was analyzed with Western blot. To our knowledge, these proteins with antigenicity were identified for the first time in N. farcinica and they may help elucidate the pathogenesis underlying Nocardia and provide potential future diagnostic markers.
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Affiliation(s)
- Shuai Xu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xuexin Hou
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Lina Sun
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jingshan Zhang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xingzhao Ji
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xuebing Wang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Heqiao Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Zhenjun Li
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
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Mycobacterium tuberculosis Rv0191 is an efflux pump of major facilitator superfamily transporter regulated by Rv1353c. Arch Biochem Biophys 2019; 667:59-66. [DOI: 10.1016/j.abb.2019.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 04/26/2019] [Accepted: 04/28/2019] [Indexed: 02/06/2023]
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31
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Mechanism and resistance for antimycobacterial activity of a fluoroquinophenoxazine compound. PLoS One 2019; 14:e0207733. [PMID: 30794538 PMCID: PMC6386362 DOI: 10.1371/journal.pone.0207733] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 02/07/2019] [Indexed: 01/28/2023] Open
Abstract
We have previously reported the inhibition of bacterial topoisomerase I activity by a fluoroquinophenoxazine compound (FP-11g) with a 6-bipiperidinyl lipophilic side chain that exhibited promising antituberculosis activity (MIC = 2.5 μM against Mycobacterium tuberculosis, SI = 9.8). Here, we found that the compound is bactericidal towards Mycobacterium smegmatis, resulting in greater than 5 Log10 reduction in colony-forming units [cfu]/mL following a 10 h incubation at 1.25 μM (4X MIC) concentration. Growth inhibition (MIC = 50 μM) and reduction in cfu could also be observed against a clinical isolate of Mycobacterium abscessus. Stepwise isolation of resistant mutants of M. smegmatis was conducted to explore the mechanism of resistance. Mutations in the resistant isolates were identified by direct comparison of whole-genome sequencing data from mutant and wild-type isolates. These include mutations in genes likely to affect the entry and retention of the compound. FP-11g inhibits Mtb topoisomerase I and Mtb gyrase with IC50 of 0.24 and 27 μM, respectively. Biophysical analysis showed that FP-11g binds DNA as an intercalator but the IC50 for inhibition of Mtb topoisomerase I activity is >10 fold lower than the compound concentrations required for producing negatively supercoiled DNA during ligation of nicked circular DNA. Thus, the DNA-binding property of FP-11g may contribute to its antimycobacterial mechanism, but that alone cannot account for the observed inhibition of Mtb topoisomerase I.
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32
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Mahmood N, Abbas SN, Faraz N, Shahid S. Mutational analysis of gyrB at amino acids: G481A & D505A in multidrug resistant (MDR) tuberculosis patients. J Infect Public Health 2019; 12:496-501. [PMID: 30738756 DOI: 10.1016/j.jiph.2019.01.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 01/03/2019] [Accepted: 01/15/2019] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The MDR (multidrug resistance) tuberculosis is a serious public health concern. Fluoroquinolones are in use to treat tuberculosis, but M. tuberculosis strains have now become resistant due to several mutations in different genes. We evaluated mutations in gyrB gene at amino acid positions G481A and D505A of M. tuberculosis by semi-multiplex allele specific (MAS) PCR. METHODS The information on gender, age, type of tuberculosis (TB), positive/negative for MDR-TB and HIV infection was gathered. The genomic DNA isolation from sputum culture samples (n=53) was carried out by non-column based method. The gyrB mutations were investigated by using self-designed primers in semi MAS-PCR, at mentioned amino acid positions. RESULTS There were 38% male patients and 62% were female patients. Most of MDR-TB patients (58.5%) were in the age between 16-30years. There were 90.5% cases of pulmonary TB and 9.4% cases of extra pulmonary TB. Only 1.8% patients were co-infected with HIV. The 24 samples had mutation in gyrB gene out of 53 (45.28%), on both of positions of amino acids Gly481Ala and Asp505Ala. All samples had mutations at Gly481Ala, whereas, 24 samples (45.28%) had mutations at Asp505Ala. CONCLUSION Mutations at amino acids positions 481 and 505 were involved in MDR-TB, which could further develop into an extensively-drug resistance (XDR) TB. Therefore, there is a need to explore all mutations in gyrB gene in MDR-TB, because it can result in a Fluoroquinolones resistance.
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Affiliation(s)
- Nasir Mahmood
- Department of Biochemistry & Department of Human Genetics and Molecular Biology, University of Health Sciences, Lahore, Pakistan; Department of Cell and Systems Biology, University of Toronto, Canada.
| | - Shahzada N Abbas
- Department of Biology, Lahore Garrison University, Lahore, Pakistan
| | - Neelam Faraz
- Department of Biology, Lahore Garrison University, Lahore, Pakistan
| | - Saman Shahid
- Department of Sciences and Humanities, National University of Computer & Emerging Sciences (NUCES), Foundation for Advancement of Science and Technology (FAST), Lahore, Pakistan
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Sanders S, Bartee D, Harrison MJ, Phillips PD, Koppisch AT, Freel Meyers CL. Growth medium-dependent antimicrobial activity of early stage MEP pathway inhibitors. PLoS One 2018; 13:e0197638. [PMID: 29771999 PMCID: PMC5957436 DOI: 10.1371/journal.pone.0197638] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 05/04/2018] [Indexed: 01/01/2023] Open
Abstract
The in vivo microenvironment of bacterial pathogens is often characterized by nutrient limitation. Consequently, conventional rich in vitro culture conditions used widely to evaluate antibacterial agents are often poorly predictive of in vivo activity, especially for agents targeting metabolic pathways. In one such pathway, the methylerythritol phosphate (MEP) pathway, which is essential for production of isoprenoids in bacterial pathogens, relatively little is known about the influence of growth environment on antibacterial properties of inhibitors targeting enzymes in this pathway. The early steps of the MEP pathway are catalyzed by 1-deoxy-d-xylulose 5-phosphate (DXP) synthase and reductoisomerase (IspC). The in vitro antibacterial efficacy of the DXP synthase inhibitor butylacetylphosphonate (BAP) was recently reported to be strongly dependent upon growth medium, with high potency observed under nutrient limitation and exceedingly weak activity in nutrient-rich conditions. In contrast, the well-known IspC inhibitor fosmidomycin has potent antibacterial activity in nutrient-rich conditions, but to date, its efficacy had not been explored under more relevant nutrient-limited conditions. The goal of this work was to thoroughly characterize the effects of BAP and fosmidomycin on bacterial cells under varied growth conditions. In this work, we show that activities of both inhibitors, alone and in combination, are strongly dependent upon growth medium, with differences in cellular uptake contributing to variance in potency of both agents. Fosmidomycin is dissimilar to BAP in that it displays relatively weaker activity in nutrient-limited compared to nutrient-rich conditions. Interestingly, while it has been generally accepted that fosmidomycin activity depends upon expression of the GlpT transporter, our results indicate for the first time that fosmidomycin can enter cells by an alternative mechanism under nutrient limitation. Finally, we show that the potency and relationship of the BAP-fosmidomycin combination also depends upon the growth medium, revealing a striking loss of BAP-fosmidomycin synergy under nutrient limitation. This change in BAP-fosmidomycin relationship suggests a shift in the metabolic and/or regulatory networks surrounding DXP accompanying the change in growth medium, the understanding of which could significantly impact targeting strategies against this pathway. More generally, our findings emphasize the importance of considering physiologically relevant growth conditions for predicting the antibacterial potential MEP pathway inhibitors and for studies of their intracellular targets.
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Affiliation(s)
- Sara Sanders
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - David Bartee
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Mackenzie J. Harrison
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Paul D. Phillips
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Andrew T. Koppisch
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- * E-mail:
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Luo T, Yuan J, Peng X, Yang G, Mi Y, Sun C, Wang C, Zhang C, Bao L. Double mutation in DNA gyrase confers moxifloxacin resistance and decreased fitness of Mycobacterium smegmatis. J Antimicrob Chemother 2018; 72:1893-1900. [PMID: 28387828 DOI: 10.1093/jac/dkx110] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 03/13/2017] [Indexed: 11/13/2022] Open
Abstract
Objectives Ofloxacin and moxifloxacin are the most commonly used fluoroquinolones (FQs) for the treatment of tuberculosis. As a new generation FQ, moxifloxacin has been recommended for the treatment of ofloxacin-resistant TB. However, the mechanism by which ofloxacin-resistant Mycobacterium tuberculosis further gains resistance to moxifloxacin remains unclear. Methods We used Mycobacterium smegmatis as a model for studying FQ resistance in M. tuberculosis . Moxifloxacin-resistant M. smegmatis was selected in vitro based on strains with primary ofloxacin resistance. The gyrA and gyrB genes of the resistant strains were sequenced to identify resistance-associated mutations. An in vitro competition assay was applied to explore the influence of gyrA / gyrB mutations on bacterial fitness. Finally, we evaluated the clinical relevance of our findings by analysing the WGS data of 1984 globally collected M. tuberculosis strains. Results A total of 57 moxifloxacin-resistant M. smegmatis strains based on five ofloxacin-resistant strains were obtained. Sequencing results revealed that all moxifloxacin-resistant strains harboured second-step mutations in gyrA or gyrB . The relative fitnesses of the double-mutation strains varied from 0.65 to 0.93 and were mostly lower than those of their mono-mutation parents. From the genomic data, we identified 37 clinical M. tuberculosis strains harbouring double mutations in gyrA and/or gyrB and 36 of them carried at least one low-level FQ-resistance mutation. Conclusions Double mutation in DNA gyrase leads to moxifloxacin resistance and decreased fitness in M. smegmatis . Under current dosing of moxifloxacin, double mutations mainly happened in M. tuberculosis strains with primary low-level resistance mutations.
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Affiliation(s)
- Tao Luo
- Laboratory of Infection and Immunity, West China Center of Medical Sciences, Sichuan University, Chengdu 610041, China
| | - Jinning Yuan
- Laboratory of Infection and Immunity, West China Center of Medical Sciences, Sichuan University, Chengdu 610041, China
| | - Xuan Peng
- Laboratory of Infection and Immunity, West China Center of Medical Sciences, Sichuan University, Chengdu 610041, China
| | - Guoping Yang
- Laboratory of Infection and Immunity, West China Center of Medical Sciences, Sichuan University, Chengdu 610041, China
| | - Youjun Mi
- Laboratory of Infection and Immunity, West China Center of Medical Sciences, Sichuan University, Chengdu 610041, China
| | - Changfeng Sun
- Laboratory of Infection and Immunity, West China Center of Medical Sciences, Sichuan University, Chengdu 610041, China
| | - Chuhan Wang
- Laboratory of Infection and Immunity, West China Center of Medical Sciences, Sichuan University, Chengdu 610041, China
| | - Chunxi Zhang
- Laboratory of Infection and Immunity, West China Center of Medical Sciences, Sichuan University, Chengdu 610041, China
| | - Lang Bao
- Laboratory of Infection and Immunity, West China Center of Medical Sciences, Sichuan University, Chengdu 610041, China
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Gough ME, Graviss EA, May EE. The dynamic immunomodulatory effects of vitamin D 3 during Mycobacterium infection. Innate Immun 2018; 23:506-523. [PMID: 28770668 DOI: 10.1177/1753425917719143] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mycobacterium tuberculosis ( Mtb), is a highly infectious airborne bacterium. Previous studies have found vitamin D3 to be a key factor in the defense against Mtb infection, through its regulation of the production of immune-related cytokines, chemokines and effector molecules. Mycobacterium smegmatis was used in our study as a surrogate of Mtb. We hypothesized that the continuous presence of vitamin D3, as well as the level of severity of infection would differentially modulate host cell immune response in comparison with control and the vehicle, ethanol. We found that vitamin D3 conditioning promotes increased bacterial clearance during low-level infection, intracellular containment during high-level infection, and minimizes host cytotoxicity. In the presence of vitamin D3 host cell production of cytokines and effector molecules was infection-level dependent, most notably IL-12, which increased during high-level infection and decreased during low-level infection, and NO, which had a rate of change positively correlated to IL-12. Our study provides evidence that vitamin D3 modulation is context-dependent and time-variant, as well as highly correlated to level of infection. This study furthers our mechanistic understanding of the dual role of vitamin D3 as a regulator of bactericidal molecules and protective agent against host cell damage.
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Affiliation(s)
- Maya E Gough
- 1 Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Edward A Graviss
- 2 Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, TX, USA
| | - Elebeoba E May
- 1 Department of Biomedical Engineering, University of Houston, Houston, TX, USA
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Whole-Cell Screen of Fragment Library Identifies Gut Microbiota Metabolite Indole Propionic Acid as Antitubercular. Antimicrob Agents Chemother 2018; 62:AAC.01571-17. [PMID: 29229639 PMCID: PMC5826148 DOI: 10.1128/aac.01571-17] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/29/2017] [Indexed: 12/22/2022] Open
Abstract
Several key antituberculosis drugs, including pyrazinamide, with a molecular mass of 123.1 g/mol, are smaller than the usual drug-like molecules. Current drug discovery efforts focus on the screening of larger compounds with molecular masses centered around 400 to 500 g/mol. Fragment (molecular mass < 300 g/mol) libraries have not been systematically explored for antitubercular activity. Here we screened a collection of 1,000 fragments, present in the Maybridge Ro3 library, for whole-cell activity against Mycobacterium tuberculosis. Twenty-nine primary hits showed dose-dependent growth inhibition equal to or better than that of pyrazinamide. The most potent hit, indole propionic acid [IPA; 3-(1H-indol-3-yl)propanoic acid], a metabolite produced by the gut microbiota, was profiled in vivo. The molecule was well tolerated in mice and showed adequate pharmacokinetic properties. In a mouse model of acute M. tuberculosis infection, IPA reduced the bacterial load in the spleen 7-fold. Our results suggest that IPA should be evaluated as an add-on to current regimens and that fragment libraries should be further explored to identify antimycobacterial lead candidates.
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González-Sánchez A, Cubillas CA, Miranda F, Dávalos A, García-de Los Santos A. The ropAe gene encodes a porin-like protein involved in copper transit in Rhizobium etli CFN42. Microbiologyopen 2017; 7:e00573. [PMID: 29280343 PMCID: PMC6011978 DOI: 10.1002/mbo3.573] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 11/19/2017] [Accepted: 11/21/2017] [Indexed: 11/16/2022] Open
Abstract
Copper (Cu) is an essential micronutrient for all aerobic forms of life. Its oxidation states (Cu+/Cu2+) make this metal an important cofactor of enzymes catalyzing redox reactions in essential biological processes. In gram‐negative bacteria, Cu uptake is an unexplored component of a finely regulated trafficking network, mediated by protein–protein interactions that deliver Cu to target proteins and efflux surplus metal to avoid toxicity. Rhizobium etliCFN42 is a facultative symbiotic diazotroph that must ensure its appropriate Cu supply for living either free in the soil or as an intracellular symbiont of leguminous plants. In crop fields, rhizobia have to contend with copper‐based fungicides. A detailed deletion analysis of the pRet42e (505 kb) plasmid from an R. etli mutant with enhanced CuCl2 tolerance led us to the identification of the ropAe gene, predicted to encode an outer membrane protein (OMP) with a β–barrel channel structure that may be involved in Cu transport. In support of this hypothesis, the functional characterization of ropAe revealed that: (I) gene disruption increased copper tolerance of the mutant, and its complementation with the wild‐type gene restored its wild‐type copper sensitivity; (II) the ropAe gene maintains a low basal transcription level in copper overload, but is upregulated when copper is scarce; (III) disruption of ropAe in an actP (copA) mutant background, defective in copper efflux, partially reduced its copper sensitivity phenotype. Finally, BLASTP comparisons and a maximum likelihood phylogenetic analysis highlight the diversification of four RopA paralogs in members of the Rhizobiaceae family. Orthologs of RopAe are highly conserved in the Rhizobiales order, poorly conserved in other alpha proteobacteria and phylogenetically unrelated to characterized porins involved in Cu or Mn uptake.
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Affiliation(s)
- Antonio González-Sánchez
- Programa de Ingeniería Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Ciro A Cubillas
- Deparment of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Fabiola Miranda
- Deparment of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Araceli Dávalos
- Programa de Ingeniería Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Alejandro García-de Los Santos
- Programa de Ingeniería Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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Bhunu B, Mautsa R, Mukanganyama S. Inhibition of biofilm formation in Mycobacterium smegmatis by Parinari curatellifolia leaf extracts. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 17:285. [PMID: 28558683 PMCID: PMC5450307 DOI: 10.1186/s12906-017-1801-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 05/19/2017] [Indexed: 12/29/2022]
Abstract
Background Tuberculosis (TB) is a serious public health problem worldwide. Mycobacterium tuberculosis (M. tuberculosis) grows as drug tolerant pellicles. Agents that inhibit biofilm formation in M. tuberculosis have the potential to reduce the disease treatment period and improve the quality of tuberculosis chemotherapy. Parinari curatellifolia (P. curatellifolia) leaf extracts are claimed to treat symptoms similar to tuberculosis in ethnomedicinal practices. Mycobacterium smegmatis (M. smegmatis) is a surrogate organism used in antimycobacterial drug discovery assays. In this study, the effect of the leaf extracts of P. curatellifolia on M. smegmatis growth and biofilm formation was investigated in order to determine the basis of its use in traditional medicinal use. Methods Phytochemicals from P. curatellifolia leaves were prepared using a mixture of 50% dichloromethane (DCM): 50% methanol and by serial exhaustive extraction using different solvents of decreasing polarity. The solvents were used in the following order, hexane > dichloromethane > ethyl acetate > acetone >ethanol > methanol > water. The micro-broth dilution method was used as an antimycobacterial susceptibility test to screen for the extract that effectively inhibited M. smegmatis growth and biofilm formation. Biofilm quantification was performed by staining the biofilms with crystal violet and determining the amount of the stain using a spectrophotometer. In addition, the effects of combining the most active extract with kanamycin were also investigated. Results The minimum inhibitory concentrations (MIC) of the extracts were found to be 6.2 μg/ml for the acetone extract, 12.5 μg/ml for both the ethanol and the total extract and 50 μg/ml for both the methanol and ethyl acetate extracts. The ethanol extract, dichloromethane extract and water extract were the only extracts that effectively inhibited biofilm formation in M. smegmatis. Combining the ethanol extract with kanamycin enhanced the effect of the ethanol extract in terms of inhibition of biofilm formation. Conclusions P. curatellifolia leaves contain phytochemicals that have the potential to be used both as antimycobacterial and anti-biofilm formation compounds.
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Nasiri MJ, Haeili M, Ghazi M, Goudarzi H, Pormohammad A, Imani Fooladi AA, Feizabadi MM. New Insights in to the Intrinsic and Acquired Drug Resistance Mechanisms in Mycobacteria. Front Microbiol 2017; 8:681. [PMID: 28487675 PMCID: PMC5403904 DOI: 10.3389/fmicb.2017.00681] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 04/04/2017] [Indexed: 01/25/2023] Open
Abstract
Infectious diseases caused by clinically important Mycobacteria continue to be an important public health problem worldwide primarily due to emergence of drug resistance crisis. In recent years, the control of tuberculosis (TB), the disease caused by Mycobacterium tuberculosis (MTB), is hampered by the emergence of multidrug resistance (MDR), defined as resistance to at least isoniazid (INH) and rifampicin (RIF), two key drugs in the treatment of the disease. Despite the availability of curative anti-TB therapy, inappropriate and inadequate treatment has allowed MTB to acquire resistance to the most important anti-TB drugs. Likewise, for most mycobacteria other than MTB, the outcome of drug treatment is poor and is likely related to the high levels of antibiotic resistance. Thus, a better knowledge of the underlying mechanisms of drug resistance in mycobacteria could aid not only to select the best therapeutic options but also to develop novel drugs that can overwhelm the existing resistance mechanisms. In this article, we review the distinctive mechanisms of antibiotic resistance in mycobacteria.
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Affiliation(s)
- Mohammad J. Nasiri
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical SciencesTehran, Iran
| | - Mehri Haeili
- Department of Biology, Faculty of Natural Sciences, University of TabrizTabriz, Iran
| | - Mona Ghazi
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical SciencesTehran, Iran
| | - Hossein Goudarzi
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical SciencesTehran, Iran
| | - Ali Pormohammad
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical SciencesTehran, Iran
| | - Abbas A. Imani Fooladi
- Applied Microbiology Research Center, Baqiyatallah University of Medical SciencesTehran, Iran
| | - Mohammad M. Feizabadi
- Department of Microbiology, School of Medicine, Tehran University of Medical SciencesTehran, Iran
- Thoracic Research Center, Imam Khomeini Hospital, Tehran University of Medical SciencesTehran, Iran
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Cortesia C, Bello T, Lopez G, Franzblau S, de Waard J, Takiff H. Use of green fluorescent protein labeled non-tuberculous mycobacteria to evaluate the activity quaternary ammonium compound disinfectants and antibiotics. Braz J Microbiol 2016; 48:151-158. [PMID: 27789202 PMCID: PMC5221367 DOI: 10.1016/j.bjm.2016.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 04/25/2016] [Indexed: 11/24/2022] Open
Abstract
Although infections with NonTuberculous Mycobacteria have become less common in AIDS patients, they are important opportunistic infections after surgical procedures, likely because they are ubiquitous and not efficiently killed by many commonly used disinfectants. In Venezuela there have recently been many non-tuberculous mycobacteria soft tissue infections after minor surgical procedures, some apparently related to the use of a commercial disinfectant based on a Quaternary Ammonium Compound. We studied the activity of this and other quaternary ammonium compounds on different non-tuberculous mycobacteria by transforming the mycobacteria with a dnaA-gfp fusion and then monitoring fluorescence to gauge the capacity of different quaternary ammonium compounds to inhibit bacterial growth. The minimum inhibitory concentration varied for the different quaternary ammonium compounds, but M. chelonae and M. abscessus were consistently more resistant than M. smegmatis, and M. terrae more resistant than M. bovis BCG.
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Affiliation(s)
- Claudia Cortesia
- Instituto Venezolano de Investigaciones Científicas, Laboratorio de Genética Molecular, Altos de Pipe, Miranda, Venezuela
| | - Teresita Bello
- Universidad Central de Venezuela (UCV), Laboratorio de Tuberculosis, Instituto de Biomedicina, Caracas, Venezuela
| | - Gustavo Lopez
- Instituto Venezolano de Investigaciones Científicas, Laboratorio de Genética Molecular, Altos de Pipe, Miranda, Venezuela
| | - Scott Franzblau
- University of Illinois at Chicago, Institute for Tuberculosis Research, Department of Medicinal Chemistry and Pharmacognosy, Chicago, United States
| | - Jacobus de Waard
- Universidad Central de Venezuela (UCV), Laboratorio de Tuberculosis, Instituto de Biomedicina, Caracas, Venezuela
| | - Howard Takiff
- Instituto Venezolano de Investigaciones Científicas, Laboratorio de Genética Molecular, Altos de Pipe, Miranda, Venezuela.
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Mendes V, Blundell TL. Targeting tuberculosis using structure-guided fragment-based drug design. Drug Discov Today 2016; 22:546-554. [PMID: 27742535 DOI: 10.1016/j.drudis.2016.10.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/30/2016] [Accepted: 10/04/2016] [Indexed: 01/20/2023]
Abstract
Fragment-based drug discovery is now widely used in academia and industry to obtain small molecule inhibitors for a given target and is established for many fields of research including antimicrobials and oncology. Many molecules derived from fragment-based approaches are already in clinical trials and two - vemurafenib and venetoclax - are on the market, but the approach has been used sparsely in the tuberculosis field. Here, we describe the progress of our group and others, and examine the most recent successes and challenges in developing compounds with antimycobacterial activity.
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Affiliation(s)
- Vitor Mendes
- Department of Biochemistry, University of Cambridge, Cambridge CB21GA, UK
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, Cambridge CB21GA, UK.
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8-Hydroxyquinolines Are Boosting Agents of Copper-Related Toxicity in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2016; 60:5765-76. [PMID: 27431227 DOI: 10.1128/aac.00325-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 07/06/2016] [Indexed: 12/13/2022] Open
Abstract
Copper (Cu) ions are likely the most important immunological metal-related toxin utilized in controlling bacterial infections. Impairment of bacterial Cu resistance reduces viability within the host. Thus, pharmacological enhancement of Cu-mediated antibacterial toxicity may lead to novel strategies in drug discovery and development. Screening for Cu toxicity-enhancing antibacterial molecules identified 8-hydroxyquinoline (8HQ) to be a potent Cu-dependent bactericidal inhibitor of Mycobacterium tuberculosis The MIC of 8HQ in the presence of Cu was 0.16 μM for replicating and nonreplicating M. tuberculosis cells. We found 8HQ's activity to be dependent on the presence of extracellular Cu and to be related to an increase in cell-associated labile Cu ions. Both findings are consistent with 8HQ acting as a Cu ionophore. Accordingly, we identified the 1:1 complex of 8HQ and Cu to be its active form, with Zn, Fe, or Mn neither enhancing nor reducing its Cu-specific action. This is remarkable, considering that the respective metal complexes have nearly identical structures and geometries. Finally, we found 8HQ to kill M. tuberculosis selectively within infected primary macrophages. Given the stark Cu-dependent nature of 8HQ activity, this is the first piece of evidence that Cu ions within macrophages may bestow antibacterial properties to a Cu-dependent inhibitor of M. tuberculosis In conclusion, our findings highlight the metal-binding ability of the 8-hydroxyquinoline scaffold to be a potential focus for future medicinal chemistry and highlight the potential of innate immunity-inspired screening platforms to reveal molecules with novel modes of action against M. tuberculosis.
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Dinos GP, Athanassopoulos CM, Missiri DA, Giannopoulou PC, Vlachogiannis IA, Papadopoulos GE, Papaioannou D, Kalpaxis DL. Chloramphenicol Derivatives as Antibacterial and Anticancer Agents: Historic Problems and Current Solutions. Antibiotics (Basel) 2016; 5:antibiotics5020020. [PMID: 27271676 PMCID: PMC4929435 DOI: 10.3390/antibiotics5020020] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/17/2016] [Accepted: 05/24/2016] [Indexed: 12/19/2022] Open
Abstract
Chloramphenicol (CAM) is the D-threo isomer of a small molecule, consisting of a p-nitrobenzene ring connected to a dichloroacetyl tail through a 2-amino-1,3-propanediol moiety. CAM displays a broad-spectrum bacteriostatic activity by specifically inhibiting the bacterial protein synthesis. In certain but important cases, it also exhibits bactericidal activity, namely against the three most common causes of meningitis, Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis. Resistance to CAM has been frequently reported and ascribed to a variety of mechanisms. However, the most important concerns that limit its clinical utility relate to side effects such as neurotoxicity and hematologic disorders. In this review, we present previous and current efforts to synthesize CAM derivatives with improved pharmacological properties. In addition, we highlight potentially broader roles of these derivatives in investigating the plasticity of the ribosomal catalytic center, the main target of CAM.
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Affiliation(s)
- George P Dinos
- Department of Biochemistry, School of Medicine, University of Patras, GR-26504 Patras, Greece.
| | | | - Dionissia A Missiri
- Laboratory of Synthetic Organic Chemistry, Department of Chemistry, University of Patras, GR-26504 Patras, Greece.
| | | | - Ioannis A Vlachogiannis
- Department of Biochemistry, School of Medicine, University of Patras, GR-26504 Patras, Greece.
| | - Georgios E Papadopoulos
- Department of Biochemistry and Biotechnology, University of Thessaly, Ploutonos 26, GR-41221 Larissa, Greece.
| | - Dionissios Papaioannou
- Laboratory of Synthetic Organic Chemistry, Department of Chemistry, University of Patras, GR-26504 Patras, Greece.
| | - Dimitrios L Kalpaxis
- Department of Biochemistry, School of Medicine, University of Patras, GR-26504 Patras, Greece.
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Bansal A, Mallik D, Kar D, Ghosh AS. Identification of a multidrug efflux pump in Mycobacterium smegmatis. FEMS Microbiol Lett 2016; 363:fnw128. [PMID: 27190152 DOI: 10.1093/femsle/fnw128] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2016] [Indexed: 12/21/2022] Open
Abstract
Cell wall impermeability and active efflux of drugs are among the primary reasons for drug resistance in mycobacteria. Efflux pumps are tripartite membrane localized transport proteins that expel drug molecules outside the cells. Several of such efflux pumps are annotated in mycobacteria, but few have been characterized, like MSMEG_2991, a putative efflux pump permease of Mycobacterium smegmatis To substantiate this, we overexpressed MSMEG_2991 protein in Escherichia coli 2443. Expression of MSMEG_2991 elevated the resistance towards structurally unrelated groups of antibiotics. An active antibiotic efflux pump nature of MSMEG_2991 was revealed by assessing the acquisition of ciprofloxacin in the absence and presence of the efflux pump inhibitor, carbonyl cyanide m-chlorophenyl hydrazone, indicating the involvement of proton-motive force (pmf) during the efflux activity. MSMEG_2991 expression elevated biofilm formation in E. coli by 4-fold, keeping parity to some of the earlier reported efflux pumps. In silico analysis suggested the presence of 12 transmembrane helices in MSMEG_2991 resembling EmrD efflux pump of E. coli Based on in vivo and in silico analyses, MSMEG_2991 may be designated as a pmf-mediated multidrug efflux pump protein that expels diverse groups of antibiotics and might as well be involved in the biofilm enhancement.
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Affiliation(s)
- Ankita Bansal
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
| | - Dhriti Mallik
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
| | - Debasish Kar
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
| | - Anindya S Ghosh
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
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Nguyen L. Antibiotic resistance mechanisms in M. tuberculosis: an update. Arch Toxicol 2016; 90:1585-604. [PMID: 27161440 DOI: 10.1007/s00204-016-1727-6] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 04/27/2016] [Indexed: 12/16/2022]
Abstract
Treatment of tuberculosis (TB) has been a therapeutic challenge because of not only the naturally high resistance level of Mycobacterium tuberculosis to antibiotics but also the newly acquired mutations that confer further resistance. Currently standardized regimens require patients to daily ingest up to four drugs under direct observation of a healthcare worker for a period of 6-9 months. Although they are quite effective in treating drug susceptible TB, these lengthy treatments often lead to patient non-adherence, which catalyzes for the emergence of M. tuberculosis strains that are increasingly resistant to the few available anti-TB drugs. The rapid evolution of M. tuberculosis, from mono-drug-resistant to multiple drug-resistant, extensively drug-resistant and most recently totally drug-resistant strains, is threatening to make TB once again an untreatable disease if new therapeutic options do not soon become available. Here, I discuss the molecular mechanisms by which M. tuberculosis confers its profound resistance to antibiotics. This knowledge may help in developing novel strategies for weakening drug resistance, thus enhancing the potency of available antibiotics against both drug susceptible and resistant M. tuberculosis strains.
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Affiliation(s)
- Liem Nguyen
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
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The Molecular Genetics of Fluoroquinolone Resistance in Mycobacterium tuberculosis. Microbiol Spectr 2016; 2:MGM2-0009-2013. [PMID: 26104201 DOI: 10.1128/microbiolspec.mgm2-0009-2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The fluoroquinolones (FQs) are synthetic antibiotics effectively used for curing patients with multidrug-resistant tuberculosis (TB). When a multidrug-resistant strain develops resistance to the FQs, as in extensively drug-resistant strains, obtaining a cure is much more difficult, and molecular methods can help by rapidly identifying resistance-causing mutations. The only mutations proven to confer FQ resistance in M. tuberculosis occur in the FQ target, the DNA gyrase, at critical amino acids from both the gyrase A and B subunits that form the FQ binding pocket. GyrA substitutions are much more common and generally confer higher levels of resistance than those in GyrB. Molecular techniques to detect resistance mutations have suboptimal sensitivity because gyrase mutations are not detected in a variable percentage of phenotypically resistant strains. The inability to find gyrase mutations may be explained by heteroresistance: bacilli with a resistance-conferring mutation are present only in a minority of the bacterial population (>1%) and are therefore detected by the proportion method, but not in a sufficient percentage to be reliably detected by molecular techniques. Alternative FQ resistance mechanisms in other bacteria--efflux pumps, pentapeptide proteins, or enzymes that inactivate the FQs--have not yet been demonstrated in FQ-resistant M. tuberculosis but may contribute to intrinsic levels of resistance to the FQs or induced tolerance leading to more frequent gyrase mutations. Moxifloxacin is currently the best anti-TB FQ and is being tested for use with other new drugs in shorter first-line regimens to cure drug-susceptible TB.
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Jamet S, Slama N, Domingues J, Laval F, Texier P, Eynard N, Quémard A, Peixoto A, Lemassu A, Daffé M, Cam K. The Non-Essential Mycolic Acid Biosynthesis Genes hadA and hadC Contribute to the Physiology and Fitness of Mycobacterium smegmatis. PLoS One 2015; 10:e0145883. [PMID: 26701652 PMCID: PMC4689354 DOI: 10.1371/journal.pone.0145883] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/09/2015] [Indexed: 12/11/2022] Open
Abstract
Gram positive mycobacteria with a high GC content, such as the etiological agent of tuberculosis Mycobacterium tuberculosis, possess an outer membrane mainly composed of mycolic acids (MAs), the so-called mycomembrane, which is essential for the cell. About thirty genes are involved in the biosynthesis of MAs, which include the hadA, hadB and hadC genes that encode the dehydratases Fatty Acid Synthase type II (FAS-II) known to function as the heterodimers HadA-HadB and HadB-HadC. The present study shows that M. smegmatis cells remain viable in the absence of either HadA and HadC or both. Inactivation of HadC has a dramatic effect on the physiology and fitness of the mutant strains whereas that of HadA exacerbates the phenotype of a hadC deletion. The hadC mutants exhibit a novel MA profile, display a distinct colony morphology, are less aggregated, are impaired for sliding motility and biofilm development and are more resistant to detergent. Conversely, the hadC mutants are significantly more susceptible to low- and high-temperature and to selective toxic compounds, including several current anti-tubercular drugs.
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Affiliation(s)
- Stevie Jamet
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Nawel Slama
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Joana Domingues
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Françoise Laval
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Pauline Texier
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Nathalie Eynard
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Annaik Quémard
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Antonio Peixoto
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Anne Lemassu
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Mamadou Daffé
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
| | - Kaymeuang Cam
- Centre National de la Recherche Scientifique, IPBS, UMR 5089, F-31077 Toulouse, France
- Univ. Toulouse, UPS, F-31000 Toulouse, France
- * E-mail:
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The Mycobacterium tuberculosis relBE toxin:antitoxin genes are stress-responsive modules that regulate growth through translation inhibition. J Microbiol 2015; 53:783-95. [PMID: 26502963 DOI: 10.1007/s12275-015-5333-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/30/2015] [Accepted: 10/05/2015] [Indexed: 12/11/2022]
Abstract
Toxin-antitoxin (TA) genes are ubiquitous among bacteria and are associated with persistence and dormancy. Following exposure to unfavorable environmental stimuli, several species (Escherichia coli, Staphylococcus aureus, Myxococcus xanthus) employ toxin proteins such as RelE and MazF to downregulate growth or initiate cell death. Mycobacterium tuberculosis possesses three Rel TA modules (Rel Mtb ): RelBE Mtb , RelFG Mtb and RelJK Mtb (Rv1246c-Rv1247c, Rv2865-Rv2866, and Rv3357-Rv3358, respectively), which inhibit mycobacterial growth when the toxin gene (relE, relG, relK) is expressed independently of the antitoxin gene (relB, relF, relJ). In the present study, we examined the in vivo mechanism of the RelE Mtb toxin protein, the impact of RelE Mtb on M. tuberculosis physiology and the environmental conditions that regulate all three rel Mtb modules. RelE Mtb negatively impacts growth and the structural integrity of the mycobacterial envelope, generating cells with aberrant forms that are prone to extensive aggregation. At a time coincident with growth defects, RelE Mtb mediates mRNA degradation in vivo resulting in significant changes to the proteome. We establish that rel Mtb modules are stress responsive, as all three operons are transcriptionally activated following mycobacterial exposure to oxidative stress or nitrogen-limiting growth environments. Here we present evidence that the rel Mtb toxin:antitoxin family is stress-responsive and, through the degradation of mRNA, the RelE Mtb toxin influences the growth, proteome and morphology of mycobacterial cells.
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Sasmal PK, Mishra TS, Rath S, Meher S, Mohapatra D. Port site infection in laparoscopic surgery: A review of its management. World J Clin Cases 2015; 3:864-871. [PMID: 26488021 PMCID: PMC4607803 DOI: 10.12998/wjcc.v3.i10.864] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/08/2015] [Accepted: 07/27/2015] [Indexed: 02/05/2023] Open
Abstract
Laparoscopic surgery (LS), also termed minimal access surgery, has brought a paradigm shift in the approach to modern surgical care. Early postoperative recovery, less pain, improved aesthesis and early return to work have led to its popularity both amongst surgeons and patients. Its application has progressed from cholecystectomies and appendectomies to various other fields including gastrointestinal surgery, urology, gynecology and oncosurgery. However, LS has its own package of complications. Port site infection (PSI), although infrequent, is one of the bothersome complications which undermine the benefits of minimal invasive surgery. Not only does it add to the morbidity of the patient but also spoils the reputation of the surgeon. Despite the advances in the field of antimicrobial agents, sterilization techniques, surgical techniques, operating room ventilation, PSIs still prevail. The emergence of rapid growing atypical mycobacteria with multidrug resistance, which are the causative organism in most of the cases, has further compounded the problem. PSIs are preventable if appropriate measures are taken preoperatively, intraoperatively and postoperatively. PSIs can often be treated non-surgically, with early identification and appropriate management. Macrolides, quinolones and aminoglycosides antibiotics do show promising activity against the atypical mycobacteria. This review article highlights the clinical burden, presentations and management of PSIs in LS as shared by various authors in the literature. We have given emphasis to atypical mycobacteria, which are emerging as a common etiological agent for PSIs in LS. Although the existing literature lacks consensus regarding PSI management, the complication can be best avoided by strictly abiding by the commandments of sterilization techniques of the laparoscopic instruments with appropriate sterilizing agent.
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