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New β-lactam - Tetramic acid hybrids show promising antibacterial activities. Bioorg Med Chem Lett 2018; 28:3105-3112. [PMID: 30097368 DOI: 10.1016/j.bmcl.2018.07.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/07/2018] [Accepted: 07/10/2018] [Indexed: 11/21/2022]
Abstract
β-Lactams are the most important class of antibiotics, for which the emergence of resistance threatens their utility. As such, we explored the extent to which the tetramic acid motif, frequently found in naturally occurring antibiotics, can be used to generate novel β-lactam antibiotics with improved antibacterial activity. We synthesized new ampicillin - tetramic acid, cephalosporin - tetramic acid, and cephamycin - tetramic acid analogs and evaluated their activities against problematic Gram-positive and Gram-negative pathogens. Amongst the analogs, a 7-aminocephalosporanic acid analog, 3397, and a 7-amino-3-vinyl cephalosporanic acid, 3436, showed potent activities against S. aureus NRS 70 (MRSA) with MICs of 6.25 μg/mL and 3.13 μg/mL respectively. These new analogs were ≥16-fold more potent than cefaclor and cephalexin. Additionally, a Δ2 cephamycin - tetramic acid analog 3474 which contained a basic guanidinium substituent at the 5-position of the tetramic acid core displayed potent activity against several clinical strains of K. pneumoniae and E. coli.
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Bhatt R, Chudaev M, Mandecki W, Goldman E. Engineered EF-Tu and tRNA-Based FRET Screening Assay to Find Inhibitors of Protein Synthesis in Bacteria. Assay Drug Dev Technol 2018; 16:212-221. [DOI: 10.1089/adt.2018.843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Rachana Bhatt
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Maxim Chudaev
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Wlodek Mandecki
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Emanuel Goldman
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey
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Skepper CK, Moreau RJ, Appleton BA, Benton BM, Drumm JE, Feng BY, Geng M, Hu C, Li C, Lingel A, Lu Y, Mamo M, Mergo W, Mostafavi M, Rath CM, Steffek M, Takeoka KT, Uehara K, Wang L, Wei JR, Xie L, Xu W, Zhang Q, de Vicente J. Discovery and Optimization of Phosphopantetheine Adenylyltransferase Inhibitors with Gram-Negative Antibacterial Activity. J Med Chem 2018; 61:3325-3349. [DOI: 10.1021/acs.jmedchem.7b01861] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Colin K. Skepper
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Robert J. Moreau
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Brent A. Appleton
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Bret M. Benton
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Joseph E. Drumm
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Brian Y. Feng
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Mei Geng
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Cheng Hu
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Cindy Li
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Andreas Lingel
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Yipin Lu
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Mulugeta Mamo
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Wosenu Mergo
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Mina Mostafavi
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Christopher M. Rath
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Micah Steffek
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Kenneth T. Takeoka
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Kyoko Uehara
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Lisha Wang
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Jun-Rong Wei
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Lili Xie
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Wenjian Xu
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Qiong Zhang
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Javier de Vicente
- Novartis Institutes for Biomedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
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Zhang M, Shen Z, Rollins D, Fales W, Zhang S. Pilot Study of Antimicrobial Resistance in Northern Bobwhites (Colinus virginianus). Avian Dis 2018; 61:391-396. [PMID: 28957012 DOI: 10.1637/11629-031517-regr] [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] [Indexed: 11/05/2022]
Abstract
Antimicrobial resistance (AMR) is an important issue for both wildlife conservation and public health. The purpose of this study was to screen for AMR in fecal bacteria isolated from northern bobwhite (Colinus virginianus), a species that is an ecologically and economically important natural resource in the southern United States. The antimicrobial susceptibility profiles of 45 Escherichia coli isolates, 20 Enterococcus faecalis isolates, and 10 Enterococcus faecium isolates were determined using the SensititerTM microbroth dilution minimum inhibitory concentration (MIC) plate, AVIAN1F. Overall, E. coli isolates had high MIC values for the following classes of antimicrobials: aminocoumarins, beta-lactams, lincosamides, macrolides, florfenicol, and sulfonamides. Enterococcus faecalis and E. faecium isolates had high MICs for aminocyclitols, aminoglycosides, beta-lactams, lincosamides, and sulfonamides. Enterococcus faecalis isolates also showed high MICs for aminocoumarins, while E. faecium isolates had high MICs for trimethoprim/sulfamethoxazole and tetracycline. Based on available veterinary interpretive criteria, 15% and 33% of E. coli isolates were resistant to sulphathiazole and sulphadimethoxine, respectively. Intermediate susceptibility to florfenicol was seen with 17.8% of E. coli isolates. Twenty percent of E. faecalis and 80% of E. faecium isolates were resistant to high-concentration streptomycin. One third of E. faecalis and 70% of E. faecium isolates were intermediately susceptible to erythromycin. Ten percent of E. faecium isolates were resistant to tetracycline and oxytetracycline. A comparison of available MIC suggests that AMR in wild bobwhite is less severe than in domestic poultry. Further investigation is needed to determine the source of AMR in wild bobwhite.
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Affiliation(s)
- Michael Zhang
- A Department of Biomedical Sciences and Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - Zhenyu Shen
- B Department of Veterinary Pathobiology and Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - Dale Rollins
- C Rolling Plains Quail Research Foundation, Roby, TX 76956
| | - William Fales
- B Department of Veterinary Pathobiology and Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
| | - Shuping Zhang
- B Department of Veterinary Pathobiology and Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211
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Moreau RJ, Skepper CK, Appleton BA, Blechschmidt A, Balibar CJ, Benton BM, Drumm JE, Feng BY, Geng M, Li C, Lindvall MK, Lingel A, Lu Y, Mamo M, Mergo W, Polyakov V, Smith TM, Takeoka K, Uehara K, Wang L, Wei JR, Weiss AH, Xie L, Xu W, Zhang Q, de Vicente J. Fragment-Based Drug Discovery of Inhibitors of Phosphopantetheine Adenylyltransferase from Gram-Negative Bacteria. J Med Chem 2018; 61:3309-3324. [DOI: 10.1021/acs.jmedchem.7b01691] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Robert J. Moreau
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Colin K. Skepper
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Brent A. Appleton
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Anke Blechschmidt
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Carl J. Balibar
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Bret M. Benton
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Joseph E. Drumm
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Brian Y. Feng
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Mei Geng
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Cindy Li
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Mika K. Lindvall
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Andreas Lingel
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Yipin Lu
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Mulugeta Mamo
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Wosenu Mergo
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Valery Polyakov
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Thomas M. Smith
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Kenneth Takeoka
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Kyoko Uehara
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Lisha Wang
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Jun-Rong Wei
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Andrew H. Weiss
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Lili Xie
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Wenjian Xu
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Qiong Zhang
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
| | - Javier de Vicente
- Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, California 94608, United States
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Ryan L, Daly P, Cullen I, Doyle M. Epididymo-orchitis caused by enteric organisms in men > 35 years old: beyond fluoroquinolones. Eur J Clin Microbiol Infect Dis 2018; 37:1001-1008. [PMID: 29450767 DOI: 10.1007/s10096-018-3212-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 02/08/2018] [Indexed: 11/26/2022]
Abstract
Epididymo-orchitis is a common urological condition in men of all ages, causing a unilateral or bilateral swelling of the epididymis and/or testis. It is frequently caused by sexually transmitted infections, Chlamydia trachomatis and Neisseria gonorrheae, as well as common enteric organisms implicated in urinary tract infections. Men over 35 years old may develop epididymo-orchitis associated with enteric organisms, often associated with functional bladder outlet problems such as benign prostatic hyperplasia or urethral stricture disease. Fluoroquinolones, especially ciprofloxacin, have long been the mainstay of treatment for these infections; however, rising resistance to ciprofloxacin in E. coli isolates in Europe and the USA means that there is an unprecedented necessity for alternative antimicrobials with adequate penetration into genital tissues (epididymis and testes) to allow appropriate and comprehensive treatment of epididymo-orchitis in this group of patients.
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Affiliation(s)
- Laura Ryan
- Department of Clinical Microbiology, University Hospital Waterford, Waterford, Ireland.
| | - Padraig Daly
- Department of Urology, University Hospital Waterford, Waterford, Ireland
| | - Ivor Cullen
- Department of Urology, University Hospital Waterford, Waterford, Ireland
| | - Maeve Doyle
- Department of Clinical Microbiology, University Hospital Waterford, Waterford, Ireland
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Antimicrobial resistance mechanisms and potential synthetic treatments. Future Sci OA 2018; 4:FSO290. [PMID: 29682325 PMCID: PMC5905577 DOI: 10.4155/fsoa-2017-0109] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 01/15/2018] [Indexed: 12/26/2022] Open
Abstract
Since the discovery of antibiotics by Sir Alexander Fleming they have been used throughout medicine and play a vital role in combating microorganisms. However, with their vast use, development of resistance has become more prevalent and their use is currently under threat. Antibiotic resistance poses a global threat to human and animal health, with many bacterial species having developed some form of resistance and in some cases within a year of first exposure to antimicrobial agents. This review aims to examine some of the mechanisms behind resistance. Additionally, re-engineering organisms, re-sensitizing bacteria to antibiotics and gene-editing techniques such as the clustered regularly interspaced short palindromic repeats-Cas9 system are providing novel approaches to combat bacterial resistance. To that extent, we have reviewed some of these novel and innovative technologies. In 1928, penicillin was discovered, changing the field of modern medicine as it provided an opportunity to treat microbial infections. Since then, microorganisms such as bacteria have evolved and now have the ability to resist a wide variety of agents that might otherwise prevent their growth. By 2050, it is estimated that around 10 million lives each year will be lost due to these bacteria. This article provides an insight into how bacteria resist antibiotics and potential new methods of treating these organisms.
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Chen L, Zhang Y, Du J, Zhang X, Li M, Chen H, Yu X, Sun Y, Zhou T. Description and plasmid characterization of the qnrD determinant in Proteeae in Wenzhou, Southern China. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2018; 51:115-122. [DOI: 10.1016/j.jmii.2016.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 11/04/2015] [Accepted: 02/07/2016] [Indexed: 11/24/2022]
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Karami P, Bazmamoun H, Sedighi I, Mozaffari Nejad AS, Aslani MM, Alikhani MY. Antibacterial resistance patterns of extended spectrum β-lactamase -producing enteropathogenic Escherichia coli strains isolated from children. Arab J Gastroenterol 2017; 18:206-209. [DOI: 10.1016/j.ajg.2017.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 08/04/2017] [Accepted: 11/19/2017] [Indexed: 10/18/2022]
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A novel recombinant vaccine candidate comprising PBP2a and autolysin against Methicillin Resistant Staphylococcus aureus confers protection in the experimental mice. Mol Immunol 2017; 91:1-7. [DOI: 10.1016/j.molimm.2017.08.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 08/01/2017] [Accepted: 08/14/2017] [Indexed: 11/18/2022]
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Westfall DA, Krishnamoorthy G, Wolloscheck D, Sarkar R, Zgurskaya HI, Rybenkov VV. Bifurcation kinetics of drug uptake by Gram-negative bacteria. PLoS One 2017; 12:e0184671. [PMID: 28926596 PMCID: PMC5604995 DOI: 10.1371/journal.pone.0184671] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 08/28/2017] [Indexed: 11/18/2022] Open
Abstract
Cell envelopes of many bacteria consist of two membranes studded with efflux transporters. Such organization protects bacteria from the environment and gives rise to multidrug resistance. We report a kinetic model that accurately describes the permeation properties of this system. The model predicts complex non-linear patterns of drug uptake complete with a bifurcation, which recapitulate the known experimental anomalies. We introduce two kinetic parameters, the efflux and barrier constants, which replace those of Michaelis and Menten for trans-envelope transport. Both compound permeation and efflux display transitions, which delineate regimes of efficient and inefficient efflux. The first transition is related to saturation of the transporter by the compound and the second one behaves as a bifurcation and involves saturation of the outer membrane barrier. The bifurcation was experimentally observed in live bacteria. We further found that active efflux of a drug can be orders of magnitude faster than its diffusion into a cell and that the efficacy of a drug depends both on its transport properties and therapeutic potency. This analysis reveals novel physical principles in the behavior of the cellular envelope, creates a framework for quantification of small molecule permeation into bacteria, and should invigorate structure-activity studies of novel antibiotics.
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Affiliation(s)
- David A. Westfall
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
| | - Ganesh Krishnamoorthy
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
| | - David Wolloscheck
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
| | - Rupa Sarkar
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
| | - Helen I. Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
- * E-mail: (VVR); (HIZ)
| | - Valentin V. Rybenkov
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
- * E-mail: (VVR); (HIZ)
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Impacts of Penicillin Binding Protein 2 Inactivation on β-Lactamase Expression and Muropeptide Profile in Stenotrophomonas maltophilia. mSystems 2017; 2:mSystems00077-17. [PMID: 28861525 PMCID: PMC5574705 DOI: 10.1128/msystems.00077-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 07/28/2017] [Indexed: 12/05/2022] Open
Abstract
Inducible expression of chromosomally encoded β-lactamase(s) is a key mechanism for β-lactam resistance in Enterobacter cloacae, Citrobacter freundii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The muropeptides produced during the peptidoglycan recycling pathway act as activator ligands for β-lactamase(s) induction. The muropeptides 1,6-anhydromuramyl pentapeptide and 1,6-anhydromuramyl tripeptide are the known activator ligands for ampC β-lactamase expression in E. cloacae. Here, we dissected the type of muropepetides for L1/L2 β-lactamase expression in an mrdA deletion mutant of S. maltophilia. Distinct from the findings with the ampC system, 1,6-anhydromuramyl tetrapeptide is the candidate for ΔmrdA-mediated β-lactamase expression in S. maltophilia. Our work extends the understanding of β-lactamase induction and provides valuable information for combating the occurrence of β-lactam resistance. Penicillin binding proteins (PBPs) are involved in peptidoglycan synthesis, and their inactivation is linked to β-lactamase expression in ampR–β-lactamase module–harboring Gram-negative bacteria. There are seven annotated PBP genes, namely, mrcA, mrcB, pbpC, mrdA, ftsI, dacB, and dacC, in the Stenotrophomonas maltophilia genome, and these genes encode PBP1a, PBP1b, PBP1c, PBP2, PBP3, PBP4, and PBP6, respectively. In addition, S. maltophilia harbors two β-lactamase genes, L1 and L2, whose expression is induced via β-lactam challenge. The impact of PBP inactivation on L1/L2 expression was assessed in this study. Inactivation of mrdA resulted in increased L1/L2 expression in the absence of β-lactam challenge, and the underlying mechanism was further elucidated. The roles of ampNG, ampDI (the homologue of Escherichia coli ampD), nagZ, ampR, and creBC in L1/L2 expression mediated by a ΔmrdA mutant strain were assessed via mutant construction and β-lactamase activity determinations. Furthermore, the strain ΔmrdA-mediated change in the muropeptide profile was assessed using liquid chromatography mass spectrometry (LC-MS). The mutant ΔmrdA-mediated L1/L2 expression relied on functional AmpNG, AmpR, and NagZ, was restricted by AmpDI, and was less related to the CreBC two-component system. Inactivation of mrdA significantly increased the levels of total and periplasmic N-acetylglucosaminyl-1,6-anhydro-N-acetylmuramyl-l-alanyl-d-glutamyl-meso-diamnopimelic acid-d-alanine (GlcNAc-anhMurNAc tetrapeptide, or M4N), supporting that the critical activator ligands for mutant strain ΔmrdA-mediated L1/L2 expression are anhMurNAc tetrapeptides. IMPORTANCE Inducible expression of chromosomally encoded β-lactamase(s) is a key mechanism for β-lactam resistance in Enterobacter cloacae, Citrobacter freundii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The muropeptides produced during the peptidoglycan recycling pathway act as activator ligands for β-lactamase(s) induction. The muropeptides 1,6-anhydromuramyl pentapeptide and 1,6-anhydromuramyl tripeptide are the known activator ligands for ampC β-lactamase expression in E. cloacae. Here, we dissected the type of muropepetides for L1/L2 β-lactamase expression in an mrdA deletion mutant of S. maltophilia. Distinct from the findings with the ampC system, 1,6-anhydromuramyl tetrapeptide is the candidate for ΔmrdA-mediated β-lactamase expression in S. maltophilia. Our work extends the understanding of β-lactamase induction and provides valuable information for combating the occurrence of β-lactam resistance.
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63
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Mai B, Gao Y, Li M, Wang X, Zhang K, Liu Q, Xu C, Wang P. Photodynamic antimicrobial chemotherapy for Staphylococcus aureus and multidrug-resistant bacterial burn infection in vitro and in vivo. Int J Nanomedicine 2017; 12:5915-5931. [PMID: 28860757 PMCID: PMC5566361 DOI: 10.2147/ijn.s138185] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Background and objectives Antibiotic resistance has emerged as one of the most important determinants of outcome in patients with serious infections, along with the virulence of the underlying pathogen. Photodynamic antimicrobial chemotherapy (PACT) has been proposed as an alternative approach for the inactivation of bacteria. This study aims to evaluate the antibacterial effect of sinoporphyrin sodium (DVDMS)-mediated PACT on Staphylococcus aureus and multidrug resistant S. aureus in vitro and in vivo. Materials and methods Bacteria were incubated with DVDMS and exposed to treatment with light. After PACT treatment, colony-forming units were counted to estimate the bactericidal effect. Intracellular reactive oxygen-species production was detected by flow cytometry. Flow cytometry and fluorescence-microscopy detection of bacterial cell-membrane permeability. Enzyme-linked immunosorbent assays were used to determine expression of VEGF, TGFβ1, TNFα, IL6, and bFGF factors in burn infection. Results DVDMS-PACT effectively killed bacterial proliferation. Intracellular ROS levels were enhanced obviously in the PACT-treatment group. SYTO 9 and propidium iodide staining showed a decrease in the ratio of green:red fluorescence intensity in the PACT-treatment group in comparison to the control group. Enzyme-linked immunosorbent-assay results revealed that in the healing process, the expression of bFGF, TGFβ1, and VEGF in the treatment group were higher than in the control group, which inhibited inflammation-factor secretion. In addition, skin-tissue bacteria were reduced after treatment. Conclusion These results indicate that DVDMS-PACT presents significant bactericidal activity and promotes wound healing after burn infections.
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Affiliation(s)
- Bingjie Mai
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education.,National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an
| | - Yiru Gao
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education.,National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an
| | - Min Li
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education.,National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an
| | - Xiaobing Wang
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education.,National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an
| | - Kun Zhang
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education.,National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an
| | - Quanhong Liu
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education.,National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an
| | - Chuanshan Xu
- School of Chinese Medicine, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
| | - Pan Wang
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education.,National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an
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64
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Luppi A. Swine enteric colibacillosis: diagnosis, therapy and antimicrobial resistance. Porcine Health Manag 2017; 3:16. [PMID: 28794894 PMCID: PMC5547460 DOI: 10.1186/s40813-017-0063-4] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 05/25/2017] [Indexed: 01/19/2023] Open
Abstract
Intestinal infection with enterotoxigenic Escherichia coli (ETEC) is an important disease in swine resulting in significant economic losses. Knowledge about the epidemiology, the diagnostic approach and methods of control are of fundamental importance to tackle the disease. The ETEC causing neonatal colibacillosis mostly carry the fimbriae F4 (k88), F5 (k99), F6 (987P) or F41, while the ETEC of post-weaning diarrhoea carry the fimbriae F4 (k88) and F18. These fimbriae adhere to specific receptors on porcine intestinal brush border epithelial cells (enterocytes), starting the process of enteric infection. After this colonization, the bacteria produce one or more enterotoxins inducing diarrhoea, such as the heat stable toxin a (STa), the heat stable toxin b (STb), and the heat labile toxin (LT). A role in the pathogenesis of the disease was demonstrated for these toxins. The diagnosis of enteric colibacillosis is based on the isolation and quantification of the pathogenic E.coli coupled with the demonstration by PCR of the genes encoding for virulence factors (fimbriae and toxins). The diagnostic approach to enteric colibacillosis must consider the differential diagnosis and the potential different causes that can be involved in the outbreak. Among the different methods of control of colibacillosis, the use of antimicrobials is widely practiced and antibiotics are used in two main ways: as prophylactic or metaphylactic treatment to prevent disease and for therapeutic purposes to treat diseased pigs. An accurate diagnosis of enteric colibacillosis needs an appropriate sampling for the isolation and quantification of the ETEC responsible for the outbreak by using semi-quantitative bacteriology. Definitive diagnosis is based on the presence of characteristic lesions and results of bacteriology along with confirmation of appropriate virulence factors to identify the isolated E.coli. It is important to confirm the diagnosis and to perform antimicrobial sensitivity tests because antimicrobial sensitivity varies greatly among E. coli isolates. Growing concern on the increase of antimicrobial resistance force a more rational use of antibiotics and this can be achieved through a correct understanding of the issues related to antibiotic therapy and to the use of antibiotics by both practitioners and farmers.
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Affiliation(s)
- Andrea Luppi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna (IZSLER), Brescia, Italy
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65
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Identification of beta-Lactamases and beta-Lactam-Related Proteins in Human Pathogenic Bacteria using a Computational Search Approach. Curr Microbiol 2017; 74:915-920. [DOI: 10.1007/s00284-017-1265-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 05/11/2017] [Indexed: 10/19/2022]
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66
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Yim J, Smith JR, Rybak MJ. Role of Combination Antimicrobial Therapy for Vancomycin-Resistant Enterococcus faecium Infections: Review of the Current Evidence. Pharmacotherapy 2017; 37:579-592. [PMID: 28273381 DOI: 10.1002/phar.1922] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Enterococcus species are the second most common cause of nosocomial infections in the United States and are particularly concerning in critically ill patients with preexisting comorbid conditions. Rising resistance to antimicrobials that were historically used as front-line agents for treatment of enterococcal infections, such as ampicillin, vancomycin, and aminoglycosides, further complicates the treatment of these infections. Of particular concern are Enterococcus faecium strains that are associated with the highest rate of vancomycin resistance. The introduction of antimicrobial agents with specific activity against vancomycin-resistant Enterococcus (VRE) faecium including daptomycin, linezolid, quinupristin-dalfopristin, and tigecycline did not completely resolve this clinical dilemma. In this review, the mechanisms of action and resistance to currently available anti-VRE antimicrobial agents including newer agents such as oritavancin and dalbavancin will be presented. In addition, novel combination therapies including β-lactams and fosfomycin, and the promising results from in vitro, animal studies, and clinical experience in the treatment of VRE faecium will be discussed.
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Affiliation(s)
- Juwon Yim
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - Jordan R Smith
- Fred Wilson School of Pharmacy, High Point University, High Point, North Carolina
| | - Michael J Rybak
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan.,School of Medicine, Wayne State University, Detroit, Michigan
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67
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Qekwana DN, Oguttu JW, Sithole F, Odoi A. Patterns and predictors of antimicrobial resistance among Staphylococcus spp. from canine clinical cases presented at a veterinary academic hospital in South Africa. BMC Vet Res 2017; 13:116. [PMID: 28454567 PMCID: PMC5410067 DOI: 10.1186/s12917-017-1034-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 04/21/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Antimicrobial resistance in staphylococci, often associated with treatment failure, is increasingly reported in veterinary medicine. The aim of this study was to investigate patterns and predictors of antimicrobial resistance among Staphylococcus spp. isolates from canine samples submitted to the bacteriology laboratory at the University of Pretoria academic veterinary hospital between 2007 and 2012. Retrospective data of 334 Staphylococcus isolates were used to calculate the proportion of samples resistant to 15 antimicrobial agents. The Cochran-Armitage trend test was used to investigate temporal trends and logistic regression models were used to investigate predictors of antimicrobial resistance in Staphylococcus aureus and Staphylococcus pseudintermedius. RESULTS Results show that 98.2% (55/56) of the S. aureus isolates were resistant to at least one drug while 42.9% were multidrug resistant. Seventy-seven percent (214/278) of the S. pseudintermedius isolates were resistant to at least one drug and 25.9% (72/278) were multidrug resistant. Resistance to lincospectin was more common among S. aureus (64.3%) than S. pseudintermedius (38.9%). Similarly, resistance to clindamycin was higher in S. aureus (51.8%) than S. pseudintermedius (31.7%) isolates. There was a significant (p = 0.005) increase in S. aureus resistance to enrofloxacin over the study period. Similarly, S. pseudintermedius exhibited significant increasing temporal trend in resistance to trimethoprim-sulphamethoxazole (p = 0.004), clindamycin (p = 0.022) and orbifloxacin (p = 0.042). However, there was a significant decreasing temporal trend in the proportion of isolates resistant to doxycycline (p = 0.041), tylosin (p = 0.008), kanamycin (p = 0.017) and amoxicillin/clavulanic acid (p = 0.032). CONCLUSIONS High levels of multidrug resistance and the increasing levels of resistance to sulphonamides, lincosamides and fluoroquinolones among Staphylococcus spp. isolates in this study are concerning. Future studies will need to investigate local drivers of antimicrobial resistance to better guide control efforts to address the problem.
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Affiliation(s)
- Daniel N Qekwana
- Section of Veterinary Public Health, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - James W Oguttu
- Department of Agriculture and Animal Health, College of Agriculture and Environmental Sciences, University of South Africa, Johannesburg, South Africa
| | - Fortune Sithole
- Section of Veterinary Public Health, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis
| | - Agricola Odoi
- Section of Veterinary Public Health, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa. .,Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, USA.
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68
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Intrinsic, adaptive and acquired antimicrobial resistance in Gram-negative bacteria. Essays Biochem 2017; 61:49-59. [DOI: 10.1042/ebc20160063] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/18/2017] [Accepted: 01/23/2017] [Indexed: 12/31/2022]
Abstract
Gram-negative bacteria are responsible for a large proportion of antimicrobial-resistant infections in humans and animals. Among this class of bacteria are also some of the most successful environmental organisms. Part of this success is their adaptability to a variety of different niches, their intrinsic resistance to antimicrobial drugs and their ability to rapidly acquire resistance mechanisms. These mechanisms of resistance are not exclusive and the interplay of several mechanisms causes high levels of resistance. In this review, we explore the molecular mechanisms underlying resistance in Gram-negative organisms and how these different mechanisms enable them to survive many different stress conditions.
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69
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Abstract
Broad-spectrum antibiotics are commonly used by physicians to treat various infections. The source of infection and causative organisms are not always apparent during the initial evaluation of the patient, and antibiotics are often given empirically to patients with suspected sepsis. Fear of attempting cephalosporins and carbapenems in penicillin-allergic septic patients may result in significant decrease in the spectrum of antimicrobial coverage. Empiric antibiotic therapy should sufficiently cover all the suspected pathogens, guided by the bacteriologic susceptibilities of the medical center. It is important to understand the major pharmacokinetic properties of antibacterial agents for proper use and to minimize the development of resistance. In several septic patients, negative cultures do not exclude active infection and positive cultures may not represent the actual infection. This article will review the important differences in the spectrum of commonly used antibiotics for nosocomial bacterial infections with a particular emphasis on culture-negative sepsis and colonization.
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70
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Homologous Recombination within Large Chromosomal Regions Facilitates Acquisition of β-Lactam and Vancomycin Resistance in Enterococcus faecium. Antimicrob Agents Chemother 2016; 60:5777-86. [PMID: 27431230 PMCID: PMC5038250 DOI: 10.1128/aac.00488-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 07/06/2016] [Indexed: 02/06/2023] Open
Abstract
The transfer of DNA between Enterococcus faecium strains has been characterized both by the movement of well-defined genetic elements and by the large-scale transfer of genomic DNA fragments. In this work, we report on the whole-genome analysis of transconjugants resulting from mating events between the vancomycin-resistant E. faecium C68 strain and the vancomycin-susceptible D344RRF strain to discern the mechanism by which the transferred regions enter the recipient chromosome. Vancomycin-resistant transconjugants from five independent matings were analyzed by whole-genome sequencing. In all cases but one, the penicillin binding protein 5 (pbp5) gene and the Tn5382 vancomycin resistance transposon were transferred together and replaced the corresponding pbp5 region of D344RRF. In one instance, Tn5382 inserted independently downstream of the D344RRF pbp5 gene. Single nucleotide variant (SNV) analysis suggested that entry of donor DNA into the recipient chromosome occurred by recombination across regions of homology between donor and recipient chromosomes, rather than through insertion sequence-mediated transposition. The transfer of genomic DNA was also associated with the transfer of C68 plasmid pLRM23 and another putative plasmid. Our data are consistent with the initiation of transfer by cointegration of a transferable plasmid with the donor chromosome, with subsequent circularization of the plasmid-chromosome cointegrant in the donor prior to transfer. Entry into the recipient chromosome most commonly occurred across regions of homology between donor and recipient chromosomes.
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71
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Chapelet G, Corvec S, Montassier E, Herbreteau G, Berrut G, Batard E, de Decker L. Rapid detection of amoxicillin-susceptible Escherichia coli in fresh uncultured urine: a new tool to limit the use of broad-spectrum empirical therapy of community-acquired pyelonephritis. Int J Antimicrob Agents 2016; 47:486-9. [DOI: 10.1016/j.ijantimicag.2016.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 03/25/2016] [Accepted: 04/02/2016] [Indexed: 10/21/2022]
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72
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Scandorieiro S, de Camargo LC, Lancheros CAC, Yamada-Ogatta SF, Nakamura CV, de Oliveira AG, Andrade CGTJ, Duran N, Nakazato G, Kobayashi RKT. Synergistic and Additive Effect of Oregano Essential Oil and Biological Silver Nanoparticles against Multidrug-Resistant Bacterial Strains. Front Microbiol 2016; 7:760. [PMID: 27242772 PMCID: PMC4876125 DOI: 10.3389/fmicb.2016.00760] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 05/05/2016] [Indexed: 12/13/2022] Open
Abstract
Bacterial resistance to conventional antibiotics has become a clinical and public health problem, making therapeutic decisions more challenging. Plant compounds and nanodrugs have been proposed as potential antimicrobial alternatives. Studies have shown that oregano (Origanum vulgare) essential oil (OEO) and silver nanoparticles have potent antibacterial activity, also against multidrug-resistant strains; however, the strong organoleptic characteristics of OEO and the development of resistance to these metal nanoparticles can limit their use. This study evaluated the antibacterial effect of a two-drug combination of biologically synthesized silver nanoparticles (bio-AgNP), produced by Fusarium oxysporum, and OEO against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. OEO and bio-AgNP showed bactericidal effects against all 17 strains tested, with minimal inhibitory concentrations (MIC) ranging from 0.298 to 1.193 mg/mL and 62.5 to 250 μM, respectively. Time-kill curves indicated that OEO acted rapidly (within 10 min), while the metallic nanoparticles took 4 h to kill Gram-negative bacteria and 24 h to kill Gram-positive bacteria. The combination of the two compounds resulted in a synergistic or additive effect, reducing their MIC values and reducing the time of action compared to bio-AgNP used alone, i.e., 20 min for Gram-negative bacteria and 7 h for Gram-positive bacteria. Scanning electron microscopy (SEM) revealed similar morphological alterations in Staphylococcus aureus (non-methicillin-resistant S. aureus, non-MRSA) cells exposed to three different treatments (OEO, bio-AgNP and combination of the two), which appeared cell surface blebbing. Individual and combined treatments showed reduction in cell density and decrease in exopolysaccharide matrix compared to untreated bacterial cells. It indicated that this composition have an antimicrobial activity against S. aureus by disrupting cells. Both compounds showed very low hemolytic activity, especially at MIC levels. This study describes for the first time the synergistic and additive interaction between OEO and bio-AgNP produced by F. oxysporum against multidrug-resistant bacteria, such as MRSA, and β-lactamase- and carbapenemase-producing Escherichia coli and Acinetobacter baumannii strains. These results indicated that this combination can be an alternative in the control of infections with few or no treatment options.
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Affiliation(s)
- Sara Scandorieiro
- Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina Londrina, Brazil
| | - Larissa C de Camargo
- Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina Londrina, Brazil
| | - Cesar A C Lancheros
- Laboratory of Molecular Biology of Microorganisms, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina Londrina, Brazil
| | - Sueli F Yamada-Ogatta
- Laboratory of Molecular Biology of Microorganisms, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina Londrina, Brazil
| | - Celso V Nakamura
- Laboratory of Technological Innovation in Drug and Cosmetics Development, Department of Basic Health Sciences, Center of Health Sciences, Universidade Estadual de Maringá Maringá, Brazil
| | - Admilton G de Oliveira
- Laboratory of Microbial Ecology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina Londrina, Brazil
| | - Célia G T J Andrade
- Laboratory of Electron Microscopy and Microanalysis, Department of General Biology, Center of Biological Sciences, Universidade Estadual de Londrina Londrina, Brazil
| | - Nelson Duran
- Institute of Chemistry, Universidade Estadual de Campinas Campinas, Brazil
| | - Gerson Nakazato
- Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina Londrina, Brazil
| | - Renata K T Kobayashi
- Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina Londrina, Brazil
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73
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Cherian PT, Deshpande A, Cheramie MN, Bruhn DF, Hurdle JG, Lee RE. Design, synthesis and microbiological evaluation of ampicillin-tetramic acid hybrid antibiotics. J Antibiot (Tokyo) 2016; 70:65-72. [PMID: 27189120 PMCID: PMC5116011 DOI: 10.1038/ja.2016.52] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 03/30/2016] [Accepted: 04/18/2016] [Indexed: 12/11/2022]
Abstract
Exploiting iron-uptake pathways by conjugating β-lactam antibiotics with iron-chelators such as catechol and hydroxamic acid is a proven strategy to overcome permeability-related resistance in Gram-negative bacteria. Since naturally occurring iron chelating tetramic acids have not been previously examined for this purpose, an exploratory series of novel ampicillin-tetramic acid hybrids that structurally resemble ureidopenicillins was designed and synthesized. The new analogs were evaluated for the ability to chelate iron and their MIC activities determined against a representative panel of clinically significant bacterial pathogens. The tetramic acid β-lactam hybrids demonstrated a high affinity to iron in the order of 10−30 M3. The hybrids were less active against Gram-positive bacteria. However, against Gram-negative bacteria, their activity was species dependent with several hybrids displaying improved activity over ampicillin against wild-type Pseudomonas aeruginosa. The anti-Gram-negative activities of the hybrids improved in the presence of clavulanic acid revealing that the tetramic acid moiety did not provide added protection against β-lactamases. Additionally, the hybrids were found to be efflux pump substrates as their activities markedly improved against pump-inactivated strains. Unlike the catechol and hydroxamic acid siderophore β-lactam conjugates, the activities of the hybrids did not improve under iron-deficient conditions. These results suggest that the tetramic acid hybrids gain permeability via different membrane receptors, or they are out competed by native bacterial siderophores with stronger affinities for iron. This study provides a foundation for the further exploitation of the tetramic acid moiety to achieve novel β-lactam anti-Gram-negative agents, providing that efflux and β-lactamase mediated resistance is addressed.
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Affiliation(s)
- Philip T Cherian
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Aditi Deshpande
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, USA
| | - Martin N Cheramie
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN, USA
| | - David F Bruhn
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Julian G Hurdle
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, USA.,Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College of Medicine, Bryan, TX, USA
| | - Richard E Lee
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN, USA
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74
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Suwantarat N, Carroll KC. Epidemiology and molecular characterization of multidrug-resistant Gram-negative bacteria in Southeast Asia. Antimicrob Resist Infect Control 2016; 5:15. [PMID: 27148448 PMCID: PMC4855802 DOI: 10.1186/s13756-016-0115-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 04/20/2016] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Multidrug-resistant Gram-negative bacteria (MDRGN), including extended-spectrum β-lactamases (ESBLs) and multidrug-resistant glucose-nonfermenting Gram-negative bacilli (nonfermenters), have emerged and spread throughout Southeast Asia. METHODS We reviewed and summarized current critical knowledge on the epidemiology and molecular characterization of MDRGN in Southeast Asia by PubMed searches for publications prior to 10 March 2016 with the term related to "MDRGN definition" combined with specific Southeast Asian country names (Thailand, Singapore, Malaysia, Vietnam, Indonesia, Philippines, Laos, Cambodia, Myanmar, Brunei). RESULTS There were a total of 175 publications from the following countries: Thailand (77), Singapore (35), Malaysia (32), Vietnam (23), Indonesia (6), Philippines (1), Laos (1), and Brunei (1). We did not find any publications on MDRGN from Myanmar and Cambodia. We did not include publications related to Shigella spp., Salmonella spp., and Vibrio spp. and non-human related studies in our review. English language articles and abstracts were included for analysis. After the abstracts were reviewed, data on MDRGN in Southeast Asia from 54 publications were further reviewed and included in this study. CONCLUSIONS MDRGNs are a major contributor of antimicrobial-resistant bacteria in Southeast Asia. The high prevalence of ESBLs has been a major problem since 2005 and is possibly related to the development of carbapenem resistant organisms in this region due to the overuse of carbapenem therapy. Carbapenem-resistant Acinetobacter baumannii is the most common pathogen associated with nosocomial infections in this region followed by carbapenem-resistant Pseudomonas aeruginosa. Although Southeast Asia is not an endemic area for carbapenem-resistant Enterobacteriaceae (CRE), recently, the rate of CRE detection has been increasing. Limited infection control measures, lack of antimicrobial control, such as the presence of active antimicrobial stewardship teams in the hospital, and outpatient antibiotic restrictions, and travel throughout this region have likely contributed to the increase in MDRGN prevalence.
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Affiliation(s)
- Nuntra Suwantarat
- Chulabhorn International College of Medicine, Thammasat University, Pathumthani, 12120 Thailand ; Division of Medical Microbiology, Johns Hopkins University School of Medicine, Mayer B1-193, 600 North Wolfe Street, Baltimore, MD 21287-7093 USA
| | - Karen C Carroll
- Division of Medical Microbiology, Johns Hopkins University School of Medicine, Mayer B1-193, 600 North Wolfe Street, Baltimore, MD 21287-7093 USA ; Microbiology Laboratory, Johns Hopkins Hospital, Baltimore, MD USA
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75
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Kayukov IG. [The etiopathogenetic bases for antibacterial therapy and prevention of urinary tract infections]. TERAPEVT ARKH 2016; 87:123-133. [PMID: 26821430 DOI: 10.17116/terarkh20158711123-133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The paper discusses the pathogenesis of urinary tract infections, the mechanisms of resistance in their pathogens to antimicrobials and uroseptics, and approaches to defining patient management tactics.
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Affiliation(s)
- I G Kayukov
- Acad. I.P. Pavlov First Saint Petersburg State Medical University, Ministry of Health of Russia, Saint Petersburg, Russia
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76
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Boronic Acid Transition State Inhibitors Active against KPC and Other Class A β-Lactamases: Structure-Activity Relationships as a Guide to Inhibitor Design. Antimicrob Agents Chemother 2016; 60:1751-9. [PMID: 26729496 DOI: 10.1128/aac.02641-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 12/27/2015] [Indexed: 11/20/2022] Open
Abstract
Boronic acid transition state inhibitors (BATSIs) are competitive, reversible β-lactamase inhibitors (BLIs). In this study, a series of BATSIs with selectively modified regions (R1, R2, and amide group) were strategically designed and tested against representative class A β-lactamases of Klebsiella pneumoniae, KPC-2 and SHV-1. Firstly, the R1 group of compounds 1a to 1c and 2a to 2e mimicked the side chain of cephalothin, whereas for compounds 3a to 3c, 4a, and 4b, the thiophene ring was replaced by a phenyl, typical of benzylpenicillin. Secondly, variations in the R2 groups which included substituted aryl side chains (compounds 1a, 1b, 1c, 3a, 3b, and 3c) and triazole groups (compounds 2a to 2e) were chosen to mimic the thiazolidine and dihydrothiazine ring of penicillins and cephalosporins, respectively. Thirdly, the amide backbone of the BATSI, which corresponds to the amide at C-6 or C-7 of β-lactams, was also changed to the following bioisosteric groups: urea (compound 3b), thiourea (compound 3c), and sulfonamide (compounds 4a and 4b). Among the compounds that inhibited KPC-2 and SHV-1 β-lactamases, nine possessed 50% inhibitory concentrations (IC50s) of ≤ 600 nM. The most active compounds contained the thiopheneacetyl group at R1 and for the chiral BATSIs, a carboxy- or hydroxy-substituted aryl group at R2. The most active sulfonamido derivative, compound 4b, lacked an R2 group. Compound 2b (S02030) was the most active, with acylation rates (k2/K) of 1.2 ± 0.2 × 10(4) M(-1) s(-1) for KPC-2 and 4.7 ± 0.6 × 10(3) M(-1) s(-1) for SHV-1, and demonstrated antimicrobial activity against Escherichia coli DH10B carrying blaSHV variants and blaKPC-2 or blaKPC-3 and against clinical strains of Klebsiella pneumoniae and E. coli producing different class A β-lactamase genes. At most, MICs decreased from 16 to 0.5 mg/liter.
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77
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Novel Penicillin-Type Analogues Bearing a Variable Substituted 2-Azetidinone Ring at Position 6: Synthesis and Biological Evaluation. Molecules 2015; 20:22044-57. [PMID: 26690391 PMCID: PMC6332199 DOI: 10.3390/molecules201219828] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/20/2015] [Accepted: 12/02/2015] [Indexed: 11/16/2022] Open
Abstract
The synthesis and the biological activity of novel semi-synthetic β-lactam compounds containing an azetidinone moiety joined to the amino-nitrogen of the (+)-6-aminopenicillanic acid (6-APA) as new antibacterial agents is reported. The synthesized compounds were screened for their in vitro antimicrobial activity against a panel of Gram positive and Gram negative pathogens and environmental bacteria. Tested compounds displayed good antimicrobial activity against all tested Gram positive bacteria and for Staphylococcus aureus and Staphylococcus epidermidis antimicrobial activity resulted higher than that of the reference antibiotic. Additionally, in vitro cytotoxic screening was also carried out indicating that the compounds do not cause a cell vitality reduction effective at concentration next to and above those shown to be antimicrobial.
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78
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First report on rapid screening of nanomaterial-based antimicrobial agents against β-lactamase resistance using pGLO plasmid transformed Escherichia coli HB 101 K-12. APPLIED NANOSCIENCE 2015. [DOI: 10.1007/s13204-015-0506-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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79
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Abia ALK, Ubomba-Jaswa E, Momba MNB. High prevalence of multiple-antibiotic-resistant (MAR) Escherichia coli in river bed sediments of the Apies River, South Africa. ENVIRONMENTAL MONITORING AND ASSESSMENT 2015; 187:652. [PMID: 26419380 DOI: 10.1007/s10661-015-4879-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/16/2015] [Indexed: 06/05/2023]
Abstract
This study aimed at investigating the presence of antibiotic-resistant Escherichia coli in river bed sediments of the Apies River, Gauteng, South Africa, in order to better inform health management decisions designed to protect users of the river. Overall, 180 water and sediment samples were collected at 10 sites along the Apies River from January to February 2014. E. coli was enumerated using the Colilert® 18/Quanti-Tray® 2000 (IDEXX). Isolates were purified by streaking on eosin methylene blue agar followed by the indole test. Pure E. coli isolates were tested for resistance to nine antibiotics by the Kirby-Bauer disc diffusion method. Over 98% of the isolates were resistant to at least one of the antibiotics tested. The highest resistance was observed against nitrofurantoin (sediments) and ampicillin (water). Over 80% of all resistant isolates showed multiple antibiotic resistance (resistance to ≥3 antibiotics). The abundance of E. coli in the sediments not only adds to the evidence that sediments are a reservoir for bacteria and possibly other pathogens including antibiotic-resistant bacteria but also suggests that antibiotic-resistant genes could be transferred to pathogens due to the high prevalence of multiple-antibiotic-resistant (MAR) strains of E. coli observed in the sediment. Using untreated water from the Apies River following resuspension for drinking and other household purposes could pose serious health risks for users. Our results suggest that river bed sediments could serve as reservoirs for MAR bacteria including pathogens under different climatic conditions and their analysis could provide information of public health concerns.
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Affiliation(s)
- Akebe Luther King Abia
- Department of Environmental, Water and Earth Science, Tshwane University of Technology, Arcadia Campus, 175 Nelson Mandela Drive, Private Bag X 680, Pretoria, 0001, South Africa.
| | - Eunice Ubomba-Jaswa
- Natural Resources and the Environment, CSIR, PO Box 395, Pretoria, 0001, South Africa
| | - Maggy Ndombo Benteke Momba
- Department of Environmental, Water and Earth Science, Tshwane University of Technology, Arcadia Campus, 175 Nelson Mandela Drive, Private Bag X 680, Pretoria, 0001, South Africa.
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Zgurskaya HI, López CA, Gnanakaran S. Permeability Barrier of Gram-Negative Cell Envelopes and Approaches To Bypass It. ACS Infect Dis 2015; 1:512-522. [PMID: 26925460 DOI: 10.1021/acsinfecdis.5b00097] [Citation(s) in RCA: 372] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Gram-negative bacteria are intrinsically resistant to many antibiotics. Species that have acquired multidrug resistance and cause infections that are effectively untreatable present a serious threat to public health. The problem is broadly recognized and tackled at both the fundamental and applied levels. This paper summarizes current advances in understanding the molecular bases of the low permeability barrier of Gram-negative pathogens, which is the major obstacle in discovery and development of antibiotics effective against such pathogens. Gaps in knowledge and specific strategies to break this barrier and to achieve potent activities against difficult Gram-negative bacteria are also discussed.
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Affiliation(s)
- Helen I. Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Cesar A. López
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - S. Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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Czekaj T, Ciszewski M, Szewczyk EM. Staphylococcus haemolyticus - an emerging threat in the twilight of the antibiotics age. MICROBIOLOGY-SGM 2015; 161:2061-8. [PMID: 26363644 DOI: 10.1099/mic.0.000178] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Staphylococcus haemolyticus is one of the most frequent aetiological factors of staphylococcal infections. This species seems to lack the important virulence attributes described in other staphylococci. However, studies have shown that the presence of various enzymes, cytolysins and surface substances affects the virulence of S. haemolyticus. Nevertheless, none of them has been identified as crucial and determinative. Despite this, S. haemolyticus is, after Staphylococcus epidermidis, the second most frequently isolated coagulase-negative staphylococcus from clinical cases, notably from blood infections, including sepsis. This raises the question of what is the reason for the increasing clinical significance of S. haemolyticus? The most important factor might be the ability to acquire multiresistance against available antimicrobial agents, even glycopeptides. The unusual genome plasticity of S. haemolyticus strains manifested by a large number of insertion sequences and identified SNPs might contribute to its acquisition of antibiotic resistance. Interspecies transfer of SCCmec cassettes suggests that S. haemolyticus might also be the reservoir of resistance genes for other staphylococci, including Staphylococcus aureus. Taking into consideration the great adaptability and the ability to survive in the hospital environment, especially on medical devices, S. haemolyticus becomes a crucial factor in nosocomial infections caused by multiresistant staphylococci.
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Affiliation(s)
- Tomasz Czekaj
- Department of Pharmaceutical Microbiology and Microbiological Diagnostics, Medical University of Łódź, Pomorska 137, 90-235 Łódź, Poland
| | - Marcin Ciszewski
- Department of Pharmaceutical Microbiology and Microbiological Diagnostics, Medical University of Łódź, Pomorska 137, 90-235 Łódź, Poland
| | - Eligia M Szewczyk
- Department of Pharmaceutical Microbiology and Microbiological Diagnostics, Medical University of Łódź, Pomorska 137, 90-235 Łódź, Poland
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Jean SS, Liao CH, Sheng WH, Lee WS, Hsueh PR. Comparison of commonly used antimicrobial susceptibility testing methods for evaluating susceptibilities of clinical isolates of Enterobacteriaceae and nonfermentative Gram-negative bacilli to cefoperazone-sulbactam. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2015; 50:454-463. [PMID: 26454423 DOI: 10.1016/j.jmii.2015.08.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 08/25/2015] [Accepted: 08/29/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND/PURPOSE The aim of this study was to investigate the cefoperazone-sulbactam (CFP-SUL) susceptibilities of important Gram-negative bacteria (GNB) by agar dilution (reference method), disk diffusion, and two automated methods. METHODS A total of 799 GNB isolates, including Enterobacteriaceae (n = 500) and nonfermentative GNB (NFGNB, n = 299), were recovered from various clinical specimens collected at National Taiwan University Hospital, Taipei, Taiwan from November 2013 to December 2014. The agar dilution method, disk diffusion method, and two automated susceptibility systems (Phoenix and Vitek 2) were used for testing susceptibility of the isolates to CFP-SUL. Categories of susceptibility (susceptible, intermediate, or resistant) to CFP-SUL yielded from each method were interpreted according to CFP-SUL interpretive breakpoints proposed previously. The results of categorical agreement and errors obtained between the agar dilution method and the other three methods were analyzed. RESULTS The Vitek 2 system had the highest error rates against Escherichia coli (n = 150) and Enterobacter cloacae (n = 77) isolates, i.e., 6.7% and 11.7% minor errors, 8.5% and 1.7% major errors, and 40% and 20% very major errors, respectively. Additionally, the Vitek 2 system was also found to have a significantly lower sensitivity (44.4%) and lower positive predictive value (18.2%) for detecting CFP-SUL nonsusceptible E. coli isolates than other methods. For carbapenem-nonsusceptible Enterobacteriaceae isolates, the Vitek 2 system failed to detect correct susceptibility to CFP-SUL. The three methods failed to correctly detect CFP-SUL susceptibility categories against all NFGNB isolates except Pseudomonas aeruginosa. CONCLUSION The Vitek 2 system is a suboptimal method in correctly detecting CFP-SUL susceptibility categories for E. coli, E. cloacae, and carbapenem-nonsusceptible Enterobacteriaceae isolates.
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Affiliation(s)
- Shio-Shin Jean
- Emergency Department, Department of Emergency and Critical Care Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Chun-Hsing Liao
- Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Wang-Huei Sheng
- Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Wen-Sen Lee
- Division of Infectious Diseases, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Po-Ren Hsueh
- Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
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83
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Henson KER, Levine MT, Wong EAH, Levine DP. Glycopeptide antibiotics: evolving resistance, pharmacology and adverse event profile. Expert Rev Anti Infect Ther 2015; 13:1265-78. [PMID: 26165756 DOI: 10.1586/14787210.2015.1068118] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The first glycopeptide antibiotic was vancomycin, isolated from the soil in the 1950s; since then, the class has expanded to include teicoplanin and the new semisynthetic glycopeptides dalbavancin, oritavancin and telavancin. They are bactericidal, active against most Gram-positive organisms, and in a concentration-dependent manner, inhibit cell wall synthesis. Resistance to vancomycin has emerged, especially among enterococci and Staphylococcus aureus through a variety of mechanisms. This emerging resistance to vancomycin makes proper dosing and monitoring of the area under the curve/MIC critically important. The chief adverse effect of vancomycin is nephrotoxicity, which is also intricately related to its dose. The efficacy of the semisynthetic glycopeptides has been demonstrated in skin and soft-tissue infections, but remains to be seen in serious methicillin-resistant Staphylococcus aureus infections.
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Affiliation(s)
- Karl Evans R Henson
- a 1 Department of Medicine, Division of Infectious Diseases, Detroit Medical Center and Wayne State University School of Medicine, 4201 St Antoine St, Detroit, MI 48201, USA
| | - Miriam T Levine
- a 1 Department of Medicine, Division of Infectious Diseases, Detroit Medical Center and Wayne State University School of Medicine, 4201 St Antoine St, Detroit, MI 48201, USA
| | - Eunice Ann H Wong
- a 1 Department of Medicine, Division of Infectious Diseases, Detroit Medical Center and Wayne State University School of Medicine, 4201 St Antoine St, Detroit, MI 48201, USA
| | - Donald P Levine
- a 1 Department of Medicine, Division of Infectious Diseases, Detroit Medical Center and Wayne State University School of Medicine, 4201 St Antoine St, Detroit, MI 48201, USA.,b 2 Department of Medicine, Division of General Internal Medicine, Detroit Receiving Hospital and University Health Center, Detroit, MI, USA
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Pozzi R, Coles M, Linke D, Kulik A, Nega M, Wohlleben W, Stegmann E. Distinct mechanisms contribute to immunity in the lantibiotic NAI-107 producer strain Microbispora ATCC PTA-5024. Environ Microbiol 2015; 18:118-32. [PMID: 25923468 DOI: 10.1111/1462-2920.12892] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/24/2015] [Accepted: 04/25/2015] [Indexed: 11/29/2022]
Abstract
The investigation of self-resistance in antibiotic producers is important to understand the emergence of antibiotic resistance in pathogens and to improve antibiotic production. Lantibiotics are ribosomally synthesized antibiotics that mostly target peptidoglycan biosynthesis. The actinomycete Microbispora ATCC PTA-5024 produces the lantibiotic NAI-107, which interferes with peptidoglycan biosynthesis by binding bactoprenol-pyrophosphate-coupled peptidoglycan precursors. In order to understand how Microbispora counteracts the action of its own antibiotic, its peptidoglycan composition was analysed in detail. Microbispora peptidoglycan consists of muropeptides with D-Ala and Gly in similar proportion at the fourth position of the peptide stems and alternative 3-3 cross-links besides the classical 4-3 cross-links. In addition, the NAI-107 biosynthetic gene cluster (mlb) was analysed for the expression of immunity proteins. We show that distinct immunity determinants are encoded in the mlb cluster: the ABC transporter MlbYZ acting cooperatively with the transmembrane protein MlbJ and the lipoprotein MlbQ. NMR structural analysis of MlbQ revealed a hydrophobic surface patch, which is proposed to bind the cognate lantibiotic. This study demonstrates that immunity in Microbispora is not only based on one determinant but on the action of the distinct immunity proteins MlbQ, MlbYZ and MlbJ.
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Affiliation(s)
- Roberta Pozzi
- Interfaculty Institute of Microbiology and Infection Medicine Tuebingen, Microbiology/Biotechnology Department, University of Tuebingen, 72076, Tuebingen, Germany
| | - Murray Coles
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076, Tuebingen, Germany
| | - Dirk Linke
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076, Tuebingen, Germany
| | - Andreas Kulik
- Interfaculty Institute of Microbiology and Infection Medicine Tuebingen, Microbiology/Biotechnology Department, University of Tuebingen, 72076, Tuebingen, Germany
| | - Mulugeta Nega
- Interfaculty Institute of Microbiology and Infection Medicine Tuebingen, Microbial Genetics Department, University of Tuebingen, 72076, Tuebingen, Germany
| | - Wolfgang Wohlleben
- Interfaculty Institute of Microbiology and Infection Medicine Tuebingen, Microbiology/Biotechnology Department, University of Tuebingen, 72076, Tuebingen, Germany
| | - Evi Stegmann
- Interfaculty Institute of Microbiology and Infection Medicine Tuebingen, Microbiology/Biotechnology Department, University of Tuebingen, 72076, Tuebingen, Germany
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86
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Stojanoski V, Chow DC, Fryszczyn B, Hu L, Nordmann P, Poirel L, Sankaran B, Prasad BVV, Palzkill T. Structural Basis for Different Substrate Profiles of Two Closely Related Class D β-Lactamases and Their Inhibition by Halogens. Biochemistry 2015; 54:3370-80. [PMID: 25938261 DOI: 10.1021/acs.biochem.5b00298] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OXA-163 and OXA-48 are closely related class D β-lactamases that exhibit different substrate profiles. OXA-163 hydrolyzes oxyimino-cephalosporins, particularly ceftazidime, while OXA-48 prefers carbapenem substrates. OXA-163 differs from OXA-48 by one substitution (S212D) in the active-site β5 strand and a four-amino acid deletion (214-RIEP-217) in the loop connecting the β5 and β6 strands. Although the structure of OXA-48 has been determined, the structure of OXA-163 is unknown. To further understand the basis for their different substrate specificities, we performed enzyme kinetic analysis, inhibition assays, X-ray crystallography, and molecular modeling. The results confirm the carbapenemase nature of OXA-48 and the ability of OXA-163 to hydrolyze the oxyimino-cephalosporin ceftazidime. The crystal structure of OXA-163 determined at 1.72 Å resolution reveals an expanded active site compared to that of OXA-48, which allows the bulky substrate ceftazidime to be accommodated. The structural differences with OXA-48, which cannot hydrolyze ceftazidime, provide a rationale for the change in substrate specificity between the enzymes. OXA-163 also crystallized under another condition that included iodide. The crystal structure determined at 2.87 Å resolution revealed iodide in the active site accompanied by several significant conformational changes, including a distortion of the β5 strand, decarboxylation of Lys73, and distortion of the substrate-binding site. Further studies showed that both OXA-163 and OXA-48 are inhibited in the presence of iodide. In addition, OXA-10, which is not a member of the OXA-48-like family, is also inhibited by iodide. These findings provide a molecular basis for the hydrolysis of ceftazidime by OXA-163 and, more broadly, show how minor sequence changes can profoundly alter the active-site configuration and thereby affect the substrate profile of an enzyme.
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Affiliation(s)
| | | | | | | | - Patrice Nordmann
- §Medical and Molecular Microbiology "Emerging Antibiotic Resistance" Unit, Department of Medicine, Faculty of Science, University of Fribourg, 1700 Fribourg, Switzerland
| | - Laurent Poirel
- §Medical and Molecular Microbiology "Emerging Antibiotic Resistance" Unit, Department of Medicine, Faculty of Science, University of Fribourg, 1700 Fribourg, Switzerland
| | - Banumathi Sankaran
- ∥Berkeley Center for Structural Biology, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Antunes NT, Assunção P, Poveda JB, Tavío MM. Mechanisms involved in quinolone resistance in Mycoplasma mycoides subsp. capri. Vet J 2015; 204:327-32. [PMID: 25951987 DOI: 10.1016/j.tvjl.2015.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 04/07/2015] [Accepted: 04/10/2015] [Indexed: 11/27/2022]
Abstract
Mycoplasma mycoides subsp. capri is a causative agent of contagious agalactia in goats. In this study, M. mycoides subsp. capri mutants were selected for resistance to fluoroquinolones (norfloxacin, enrofloxacin and ciprofloxacin) by serial passes in broth with increasing concentrations of antibiotic. Mutations conferring cross-resistance to the three fluoroquinolones were found in the quinolone resistance determining regions of the four genes encoding DNA gyrase and topoisomerase IV. Different mutations in the DNA gyrase GyrA subunit suggest a different mechanism of inhibition between norfloxacin and the other tested fluoroquinolones. The presence of an adenosine triphosphate-dependent efflux system was suggested through the use of the inhibitor orthovanadate.
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Affiliation(s)
- Nuno T Antunes
- Unidad de Epidemiología y Medicina Preventiva, Instituto Universitario de Sanidad Animal (IUSA), Universidad de Las Palmas de Gran Canaria, 35413 Arucas, Spain.
| | - Patrícia Assunção
- Unidad de Epidemiología y Medicina Preventiva, Instituto Universitario de Sanidad Animal (IUSA), Universidad de Las Palmas de Gran Canaria, 35413 Arucas, Spain
| | - José B Poveda
- Unidad de Epidemiología y Medicina Preventiva, Instituto Universitario de Sanidad Animal (IUSA), Universidad de Las Palmas de Gran Canaria, 35413 Arucas, Spain
| | - María M Tavío
- Unidad de Epidemiología y Medicina Preventiva, Instituto Universitario de Sanidad Animal (IUSA), Universidad de Las Palmas de Gran Canaria, 35413 Arucas, Spain; Microbiología, Departamento de Ciencias Clínicas, Facultad de Ciencias de la Salud, Universidad de Las Palmas de Gran Canaria, 35016 Las Palmas de Gran Canaria, Spain
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88
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Monograph: In vitro efficacy of 30 ethnomedicinal plants used by Indian aborigines against 6 multidrug resistant Gram-positive pathogenic bacteria. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2015. [DOI: 10.1016/s2222-1808(14)60641-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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89
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Abstract
Pneumonia is a common disease that carries a high mortality. Traditionally, pneumonia has been classified and treated according to the setting where the pneumonia develops, namely community-acquired pneumonia, health-care-associated pneumonia, and hospital-acquired pneumonia. This classification was based on the risk of a patient being infected with a hospital-acquired drug-resistant pathogen. A new treatment paradigm has been proposed based on the risk of the patient being infected with a community-acquired drug-resistant pathogen. The risk factors for infection with a community-acquired drug-resistant pathogen include (1) hospitalization for > 2 days during the previous 90 days, (2) antibiotic use during the previous 90 days, (3) nonambulatory status, (4) tube feeds, (5) immunocompromised status, (6) use of acid-suppressive therapy, (7) chronic hemodialysis during the preceding 30 days, (8) positive methicillin-resistant Staphylococcus aureus history within the previous 90 days, and (9) present hospitalization > 2 days. This article reviews this new treatment paradigm and other issues relevant to the diagnosis and management of pneumonia based on information from MEDLINE, EMBASE, and the Cochrane Register of Controlled Trials.
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Affiliation(s)
- Paul E Marik
- Division of Pulmonary and Critical Care Medicine, Eastern Virginia Medical School , Norfolk, VA , USA
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In vivo pharmacokinetics and pharmacodynamics of the lantibiotic NAI-107 in a neutropenic murine thigh infection model. Antimicrob Agents Chemother 2014; 59:1258-64. [PMID: 25512404 DOI: 10.1128/aac.04444-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
NAI-107 is a novel lantibiotic compound with potent in vitro activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). The purpose of this study was to examine the activity of NAI-107 against S. aureus strains, including MRSA, in the neutropenic murine thigh infection model. Serum pharmacokinetics were determined and time-kill studies were performed following administration of single subcutaneous doses of 5, 20, and 80 mg/kg body weight. The dose fractionation included total doses ranging from 1.56 to 400 mg/kg/72 h, divided into 1, 2, 3, or 6 doses. Studies of treatment effects against 9 S. aureus strains (4 methicillin-susceptible Staphylococcus aureus [MSSA] and 5 MRSA) using a 12-h dosing interval and total dose range of 1.56 to 400 mg/kg/72 h were also performed. A maximum effect (Emax) model was used to determine the pharmacokinetic/pharmacodynamic (PK/PD) index that best described the dose-response data and to estimate the doses required to achieve a net bacteriostatic dose (SD) and a 1-log reduction in CFU/thigh. The pharmacokinetic studies demonstrated an area under the concentration-time curve (AUC) range of 26.8 to 276 mg·h/liter and half-lives of 4.2 to 8.2 h. MICs ranged from 0.125 to 0.5 μg/ml. The 2 highest single doses produced more than a 2-log kill and prolonged postantibiotic effects (PAEs) ranging from 36 to >72 h. The dose fractionation-response curves were similar, and the AUC/MIC ratio was the most predictive PD index (AUC/MIC, coefficient of determination [R2]=0.89; maximum concentration of drug in serum [Cmax]/MIC, R2=0.79; time [T]>MIC, R2=0.63). A ≥2-log kill was observed against all 9 S. aureus strains. The total drug 24-h AUC/MIC values associated with stasis and a 1-log kill for the 9 S. aureus strains were 371±130 and 510±227, respectively. NAI-107 demonstrated concentration-dependent killing and prolonged PAEs. The AUC/MIC ratio was the predictive PD index. Extensive killing was observed for S. aureus organisms, independent of the MRSA status. The AUC/MIC target should be useful for the design of clinical dosing regimens.
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92
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Sun X, Sun S, Ference C, Zhu W, Zhou N, Zhang Y, Zhou K. A potent antimicrobial compound isolated from Clathria cervicornis. Bioorg Med Chem Lett 2014; 25:67-9. [PMID: 25435146 DOI: 10.1016/j.bmcl.2014.11.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 10/29/2014] [Accepted: 11/03/2014] [Indexed: 11/17/2022]
Abstract
The sponge of Clathria cervicornis is commonly used in traditional medicine. This study aims to identify the active compound in C. cervicornis and to evaluate its antimicrobial activity. The purified active compound was determined to be crambescidin 800 and was found to be highly active against Acinetobacter baumannii (minimal inhibitory concentration, MIC=2 μg/ml), Klebsiella pneumoniae (MIC=1 μg/ml) and Pseudomonas aeruginosa (MIC=1 μg/ml). A potent antimicrobial compound, crambescidin 800, was isolated in Clathria cervicornis. It is extremely active against three common pathogenic bacteria.
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Affiliation(s)
- Xiuxiu Sun
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, United States
| | - Shi Sun
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, United States
| | | | - Wenjun Zhu
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, United States
| | - Ninghui Zhou
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, United States
| | - Yifan Zhang
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, United States
| | - Kequan Zhou
- Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, United States.
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Macesic N, Morrissey CO, Cheng AC, Spencer A, Peleg AY. Changing microbial epidemiology in hematopoietic stem cell transplant recipients: increasing resistance over a 9-year period. Transpl Infect Dis 2014; 16:887-96. [PMID: 25298044 DOI: 10.1111/tid.12298] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 06/03/2014] [Accepted: 07/12/2014] [Indexed: 11/30/2022]
Abstract
UNLABELLED Infections remain important contributors to mortality in hematopoietic stem cell transplantation (HSCT). METHOD We studied the evolving epidemiology and trends in susceptibility of bacterial and Candida isolates at an Australian HSCT center. A total of 528 HSCTs in 508 patients were performed from April 2001 to May 2010. A total of 605 isolates were eligible for study inclusion; 318 (53%) were gram-positive, 268 (44%) were gram-negative, and 19 (3%) were Candida species. RESULTS The most common site for isolates was blood (380 isolates, 63%). Staphylococcus aureus was the most common gram-positive organism (n = 107, 34%), but trends to increasing coagulase-negative staphylococci (P = 0.002) and vancomycin-resistant Enterococcus (P < 0.001) were observed. Escherichia coli was the most common gram-negative isolate (n = 74, 28%). Fluoroquinolone resistance increased with widespread use of protocol fluoroquinolone prophylaxis (P = 0.001). Carbapenem resistance was found in 44% of Pseudomonas or Acinetobacter isolates. Bloodstream infection with a multidrug-resistant organism (odds ratio 3.61, 95% confidence interval: 1.40-9.32, P = 0.008) was an independent predictor of mortality at 7 days after a positive blood culture. CONCLUSIONS Antimicrobial resistance is an increasing problem in this vulnerable patient population, and not only has an impact on choice of empiric therapy for febrile neutropenia but also on mortality.
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Affiliation(s)
- N Macesic
- Department of Infectious Diseases, Alfred Hospital, Melbourne, Victoria, Australia
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Ni H, Zhang S, Ding X, Mi T, Wang Z, Liu M. Determination of Enrofloxacin in Bovine Milk by a Novel Single-Stranded DNA Aptamer Chemiluminescent Enzyme Immunoassay. ANAL LETT 2014. [DOI: 10.1080/00032719.2014.924009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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95
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Brackett CM, Melander RJ, An IH, Krishnamurthy A, Thompson RJ, Cavanagh J, Melander C. Small-Molecule Suppression of β-Lactam Resistance in Multidrug-Resistant Gram-Negative Pathogens. J Med Chem 2014; 57:7450-8. [DOI: 10.1021/jm501050e] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christopher M. Brackett
- Department
of Chemistry and ‡Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Roberta J. Melander
- Department
of Chemistry and ‡Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Il Hwan An
- Department
of Chemistry and ‡Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Aparna Krishnamurthy
- Department
of Chemistry and ‡Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Richele J. Thompson
- Department
of Chemistry and ‡Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - John Cavanagh
- Department
of Chemistry and ‡Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Christian Melander
- Department
of Chemistry and ‡Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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Abstract
Nemonoxacin is a novel C-8-methoxy nonfluorinated quinolone with remarkably enhanced in vitro activity against a wide variety of clinically relevant pathogens, especially gram-positive bacteria, including multidrug-resistant Streptococcus pneumoniae and methicillin-resistant Staphylococcus aureus. It has a low propensity for selecting resistant pathogens than fluoroquinolones, since bacteria become resistant to nemonoxacin only when three different mutations occur in their quinolone resistance-determining regions. Nemonoxacin shows greater efficacy than most of the widely used fluoroquinolones in the murine model of systemic, pulmonary, or ascending urinary tract infection. Nemonoxacin has a sound PK profile in healthy volunteers. It rapidly reaches maximum concentration Cmax 1-2 hours after oral administration in the fasting state and has a relatively long elimination half-life of more than 10 hours, which is similar to fluoroquinolones. Approximately 60%-75% of the administered dose is excreted in unchanged form via kidneys over 24-72 hours. Phase II and III studies of oral nemonoxacin and Phase II studies of intravenous nemonoxacin have been completed in patients with community-acquired pneumonia (CAP), before which the Phase I studies of oral and intravenous nemonoxacin indicated sound tolerance and safety with healthy volunteers. The published results demonstrate that an oral dose of either 500 mg or 750 mg nemonoxacin once daily for 7 days is as effective and safe as levofloxacin 500 mg once daily for 7 days. Nemonoxacin is well-tolerated in patients with CAP. The most common adverse events of oral administration are observed in the gastrointestinal and nervous system, the incidence of which is similar to levofloxacin treatment. The Phase III studies of intravenous nemonoxacin for treating CAP and oral nemonoxacin for diabetic foot infection has been registered with promising outcomes to be expected.
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Affiliation(s)
- Xiaohua Qin
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Haihui Huang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
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97
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Misic AM, Gardner SE, Grice EA. The Wound Microbiome: Modern Approaches to Examining the Role of Microorganisms in Impaired Chronic Wound Healing. Adv Wound Care (New Rochelle) 2014; 3:502-510. [PMID: 25032070 DOI: 10.1089/wound.2012.0397] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Indexed: 01/05/2023] Open
Abstract
Significance: Bacterial burden is believed to play a significant role in impaired wound healing of chronic wounds and the development of infection-related complications. The standard of care in the clinic relies upon cultivation-dependent methods to identify microorganisms. These assays are biased toward microorganisms that thrive in isolation under laboratory conditions. Recent Advances: Significant advances in genomic technologies have enabled less-biased, culture-independent approaches to characterize microbial communities, or microbiomes. The aggregate sequencing and analysis of 16S ribosomal RNA genes has demonstrated that cultures under-represent true microbial diversity and load. Critical Issues: Despite recent advances that enable culture-independent analyses of microbiomes, those organisms that are important in impaired healing remain ambiguous. Inconsistent findings across various studies highlight the need to characterize microbiomes of chronic wounds with homogenous etiology to determine differences in microbiomes that may be driven by the wound environment and that may affect wound outcomes. Rigorous analyses of wound microbiomes in light of the three dimensions of bioburden (microbial diversity, microbial load, and pathogenic organisms), clinical metadata, and wound outcomes will be a significant step forward in our quest to understand the role of microorganisms in impaired healing. Future Directions: Longitudinal studies employing serial sampling are needed to appreciate the role of the dynamic microbial community in chronic wound healing. The value of clinical metadata needs to be examined as potential biomarkers of problematic microbiota and wound outcomes. Lastly, better characterization and understanding of wound microbiomes will open avenues for improved diagnostic and therapeutic tools for the nonhealing wound.
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Affiliation(s)
- Ana M. Misic
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Elizabeth A. Grice
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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98
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Khan S, Sallum UW, Zheng X, Nau GJ, Hasan T. Rapid optical determination of β-lactamase and antibiotic activity. BMC Microbiol 2014; 14:84. [PMID: 24708478 PMCID: PMC4234275 DOI: 10.1186/1471-2180-14-84] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/28/2014] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The absence of rapid tests evaluating antibiotic susceptibility results in the empirical prescription of antibiotics. This can lead to treatment failures due to escalating antibiotic resistance, and also furthers the emergence of drug-resistant bacteria. This study reports a rapid optical method to detect β-lactamase and thereby assess activity of β-lactam antibiotics, which could provide an approach for targeted prescription of antibiotics. The methodology is centred on a fluorescence quenching based probe (β-LEAF--β-Lactamase Enzyme Activated Fluorophore) that mimics the structure of β-lactam antibiotics. RESULTS The β-LEAF assay was performed for rapid determination of β-lactamase production and activity of β-lactam antibiotic (cefazolin) on a panel of Staphylococcus aureus ATCC strains and clinical isolates. Four of the clinical isolates were determined to be lactamase producers, with the capacity to inactivate cefazolin, out of the twenty-five isolates tested. These results were compared against gold standard methods, nitrocefin disk test for β-lactamase detection and disk diffusion for antibiotic susceptibility, showing results to be largely consistent. Furthermore, in the sub-set of β-lactamase producers, it was demonstrated and validated that multiple antibiotics (cefazolin, cefoxitin, cefepime) could be assessed simultaneously to predict the antibiotic that would be most active for a given bacterial isolate. CONCLUSIONS The study establishes the rapid β-LEAF assay for β-lactamase detection and prediction of antibiotic activity using S. aureus clinical isolates. Although the focus in the current study is β-lactamase-based resistance, the overall approach represents a broad diagnostic platform. In the long-term, these studies form the basis for the development of assays utilizing a broader variety of targets, pathogens and drugs.
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Affiliation(s)
| | | | | | | | - Tayyaba Hasan
- Wellman Centre for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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99
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Hendrickx APA, van Schaik W, Willems RJL. The cell wall architecture of Enterococcus faecium: from resistance to pathogenesis. Future Microbiol 2014; 8:993-1010. [PMID: 23902146 DOI: 10.2217/fmb.13.66] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The cell wall of Gram-positive bacteria functions as a surface organelle that continuously interacts with its environment through a plethora of cell wall-associated molecules. Enterococcus faecium is a normal inhabitant of the GI tract of mammals, but has recently become an important etiological agent of hospital-acquired infections in debilitated patients. Insights into the assembly and function of enterococcal cell wall components and their interactions with the host during colonization and infection are essential to explain the worldwide emergence of E. faecium as an important multiantibiotic-resistant nosocomial pathogen. Understanding the biochemistry of cell wall biogenesis and principles of antibiotic resistance at the molecular level may open up new frontiers in research on enterococci, particularly for the development of novel antimicrobial strategies. In this article, we outline the current knowledge on the most important antimicrobial resistance mechanisms that involve peptidoglycan synthesis and the role of cell wall constituents, including lipoteichoic acid, wall teichoic acid, capsular polysaccharides, LPxTG cell wall-anchored surface proteins, WxL-type surface proteins and pili, in the pathogenesis of E. faecium.
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Affiliation(s)
- Antoni P A Hendrickx
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
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100
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Woappi Y, Gabani P, Singh A, Singh OV. Antibiotrophs: The complexity of antibiotic-subsisting and antibiotic-resistant microorganisms. Crit Rev Microbiol 2014; 42:17-30. [PMID: 24495094 DOI: 10.3109/1040841x.2013.875982] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Widespread overuse of antibiotics has led to the emergence of numerous antibiotic-resistant bacteria; among these are antibiotic-subsisting strains capable of surviving in environments with antibiotics as the sole carbon source. This unparalleled expansion of antibiotic resistance reveals the potent and diversified resistance abilities of certain bacterial strains. Moreover, these strains often possess hypermutator phenotypes and virulence transmissibility competent for genomic and proteomic propagation and pathogenicity. Pragmatic and prospicient approaches will be necessary to develop efficient therapeutic methods against such bacteria and to understand the extent of their genomic adaptability. This review aims to reveal the niches of these antibiotic-catabolizing microbes and assesses the underlying factors linking natural microbial antibiotic production, multidrug resistance, and antibiotic-subsistence.
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Affiliation(s)
- Yvon Woappi
- a Division of Biological and Health Sciences , University of Pittsburgh , Bradford , PA , USA and
| | - Prashant Gabani
- a Division of Biological and Health Sciences , University of Pittsburgh , Bradford , PA , USA and
| | - Arya Singh
- b Department of Computer Science , Texas State University , San Marcos , TX , USA
| | - Om V Singh
- a Division of Biological and Health Sciences , University of Pittsburgh , Bradford , PA , USA and
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