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Phophi L, Petzer IM, Qekwana DN. Antimicrobial resistance patterns and biofilm formation of coagulase-negative Staphylococcus species isolated from subclinical mastitis cow milk samples submitted to the Onderstepoort Milk Laboratory. BMC Vet Res 2019; 15:420. [PMID: 31771575 PMCID: PMC6880574 DOI: 10.1186/s12917-019-2175-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 11/12/2019] [Indexed: 01/03/2023] Open
Abstract
Background Increased prevalence of antimicrobial resistance, treatment failure, and financial losses have been reported in dairy cows with coagulase-negative Staphylococcus (CoNS) clinical mastitis, however, studies on CoNS infections are limited in South Africa. Therefore, the objectives of this study were to investigate the antimicrobial resistance patterns and biofilm formation in CoNS isolated from cow milk samples submitted to the Onderstepoort Milk Laboratory. Results A total of 142 confirmed CoNS isolates were used for this study. Biofilm formation was identified in 18% of CoNS tested. Staphylococcus chromogenes (11%) had the highest proportion of biofilm formation followed by S. haemolyticus (4.0%), S. epidermidis, S. hominis, S. xylosus, and S. simulans with 1% respectively. Ninety percent (90%) of CoNS were resistant to at least one antimicrobial (AMR) and 51% were multidrug-resistant (MDR). Resistance among CoNS was the highest to ampicillin (90%) and penicillin (89%), few isolates resistant to cefoxitin and vancomycin, 9% respectively. Similarly, MDR-S. haemolyticus (44%), MDR-S. epidermidis (65%), and MDR-S. chromogenes (52%) were mainly resistant to penicillins. The most common resistance patterns observed were resistance to penicillin-ampicillin (16%) and penicillin-ampicillin-erythromycin (10%). Only 42% of biofilm positive CoNS were MDR. Conclusion The majority of CoNS in this study were resistance to penicillins. In addition, most isolates were β-lactam resistant and MDR. Biofilm formation among the CoNS in this study was uncommon and there was no significant difference in the proportion of MDR-CoNS based on the ability to form a biofilm.
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Affiliation(s)
- Lufuno Phophi
- Section Veterinary Public Health, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
| | - Inge-Marie Petzer
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
| | - Daniel Nenene Qekwana
- Section Veterinary Public Health, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
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2
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Clasen J, Birkegård AC, Græsbøll K, Folkesson A. Evolution of TEM-type extended-spectrum β-lactamases in Escherichia coli by cephalosporins. J Glob Antimicrob Resist 2019; 19:32-39. [PMID: 31048029 DOI: 10.1016/j.jgar.2019.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 02/07/2019] [Accepted: 03/18/2019] [Indexed: 10/26/2022] Open
Abstract
OBJECTIVES This study was conducted to examine the molecular mechanisms responsible for the evolution of TEM-type extended-spectrum β-lactamases (ESBLs) following selective pressure from four third-generation cephalosporins, namely ceftazidime, cefotaxime, ceftriaxone and ceftibuten. In addition, selective enrichment for ESBL detection in environmental samples was investigated. METHODS Using experimental evolution, resistant variants were isolated and mutations in TEM-1 were examined by DNA sequencing. Resistance levels and the development of cross-resistance were determined for ESBL-producing isolates by Etest and disk diffusion assay. Selective plating with or without prior growth in selective broth was used to examine the approach of selective enrichment for ESBL detection. RESULTS The third-generation cephalosporins ceftazidime, cefotaxime and ceftriaxone selected for ESBLs, whereas ceftibuten did not. All ESBL variants additionally remained susceptible to ceftibuten. DNA sequencing of the TEM-1 coding sequence of mutants revealed mutations not previously isolated through selection. This indicates that the potential for ESBL evolution is much broader than can be inferred from sequence analysis of clinical samples alone. The results also indicate that selective enrichment for enhanced detection of ESBL-producers may give unreliable results owing to the selection of spontaneous mutations in narrow-spectrum β-lactamases resulting in TEM-type ESBL-producers. CONCLUSION These results help explain the molecular changes responsible for evolution of TEM-type ESBLs and meanwhile question the appropriate use of selective enrichment for detection of ESBLs in environmental samples.
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Affiliation(s)
- Julie Clasen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
| | - Anna Camilla Birkegård
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Kaare Græsbøll
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Anders Folkesson
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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3
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Exploring anti-MRSA activity of chitosan-coated liposomal dicloxacillin. J Microbiol Methods 2019; 156:23-28. [DOI: 10.1016/j.mimet.2018.11.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 11/15/2018] [Accepted: 11/17/2018] [Indexed: 01/09/2023]
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4
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Jeong DW, Heo S, Ryu S, Blom J, Lee JH. Genomic insights into the virulence and salt tolerance of Staphylococcus equorum. Sci Rep 2017; 7:5383. [PMID: 28710456 PMCID: PMC5511256 DOI: 10.1038/s41598-017-05918-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/06/2017] [Indexed: 11/09/2022] Open
Abstract
To shed light on the genetic background behind the virulence and salt tolerance of Staphylococcus equorum, we performed comparative genome analysis of six S. equorum strains. Data on four previously published genome sequences were obtained from the NCBI database, while those on strain KM1031 displaying resistance to multiple antibiotics and strain C2014 causing haemolysis were determined in this study. Examination of the pan-genome of five of the six S. equorum strains showed that the conserved core genome retained the genes for general physiological processes and survival of the species. In this comparative genomic analysis, the factors that distinguish the strains from each other, including acquired genomic factors in mobile elements, were identified. Additionally, the high salt tolerance of strains enabling growth at a NaCl concentration of 25% (w/v) was attributed to the genes encoding potassium voltage-gated channels. Among the six strains, KS1039 does not possess any of the functional virulence determinants expressed in the other strains.
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Affiliation(s)
- Do-Won Jeong
- Department of Food and Nutrition, Dongduk Women's University, Seoul, 02748, Republic of Korea
| | - Sojeong Heo
- Department of Food Science and Biotechnology, Kyonggi University, Suwon, 16227, Republic of Korea
| | - Sangryeol Ryu
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, and Center for Food and Bioconvergence, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jochen Blom
- Bioinformatics and System Biology, Justus-Liebig-University Giessen, 35392, Giessen, Germany
| | - Jong-Hoon Lee
- Department of Food Science and Biotechnology, Kyonggi University, Suwon, 16227, Republic of Korea.
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Li L, Cheung A, Bayer AS, Chen L, Abdelhady W, Kreiswirth BN, Yeaman MR, Xiong YQ. The Global Regulon sarA Regulates β-Lactam Antibiotic Resistance in Methicillin-Resistant Staphylococcus aureus In Vitro and in Endovascular Infections. J Infect Dis 2016; 214:1421-1429. [PMID: 27543672 DOI: 10.1093/infdis/jiw386] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/11/2016] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND The global regulator sarA modulates virulence of methicillin-resistant Staphylococcus aureus (MRSA) via regulation of principal virulence factors (eg, adhesins and toxins) and biofilm formation. Resistance of S. aureus strains to β-lactam antibiotics (eg, oxacillin) depends on the production of penicillin-binding protein 2a (PBP2a), encoded by mecA METHODS: In the present study, we investigated the impact of sarA on the phenotypic and genotypic characteristics of oxacillin resistance both in vitro and in an experimental endocarditis model, using prototypic healthcare- and community-associated MRSA parental and their respective sarA mutant strain sets. RESULTS All sarA mutants (vs respective MRSA parental controls) displayed significant reductions in oxacillin resistance and biofilm formation in vitro and oxacillin persistence in an experimental endocarditis model in vivo. These phenotypes corresponded to reduced mecA expression and PBP2a production and an interdependency of sarA and sigB regulators. Moreover, RNA sequencing analyses showed that sarA mutants exhibited significantly increased levels of primary extracellular proteases and suppressed pyrimidine biosynthetic pathway, argininosuccinate lyase-encoding, and ABC transporter-related genes as compared to the parental strain. CONCLUSIONS These results suggested that sarA regulates oxacillin resistance in mecA-positive MRSA. Thus, abrogation of this regulator represents an attractive and novel drug target to potentiate efficacy of existing antibiotic for MRSA therapy.
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Affiliation(s)
- Liang Li
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center
| | | | - Arnold S Bayer
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center.,Division of Infectious Diseases.,David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Liang Chen
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark
| | - Wessam Abdelhady
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center
| | - Barry N Kreiswirth
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark
| | - Michael R Yeaman
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center.,Division of Infectious Diseases.,Division of Molecular Medicine, Los Angeles County-Harbor-UCLA Medical Center, Torrance.,David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Yan Q Xiong
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center.,Division of Infectious Diseases.,David Geffen School of Medicine at UCLA, Los Angeles, California
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Bansal BK, Gupta DK, Shafi TA, Sharma S. Comparative antibiogram of coagulase-negative Staphylococci (CNS) associated with subclinical and clinical mastitis in dairy cows. Vet World 2015; 8:421-6. [PMID: 27047108 PMCID: PMC4774854 DOI: 10.14202/vetworld.2015.421-426] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 02/19/2015] [Accepted: 03/01/2015] [Indexed: 11/23/2022] Open
Abstract
Aim: The present study was planned to determine the in vitro antibiotic susceptibility of coagulase-negative Staphylococci (CNS) strains isolated from clinical and subclinical cases of mastitis in dairy cows. Antibiotic sensitivity profile will be helpful to recommend early therapy at the field level prior to availability of CST results. Materials and Methods: The milk samples from cases of clinical mastitis received in Mastitis Laboratory, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana and those of subclinical mastitis collected during routine screening of state dairy farms, were subjected to microbial culture. Identification of CNS organisms was done by standard biochemical tests. Antibiotic sensitivity testing, based on 30 antibiotics belonging to 12 groups, was done on 58 randomly selected CNS isolates (clinical isolates: 41, subclinical isolates: 17). Results: Isolates were highly susceptible to chloramphenicol (98.3%), gentamicin (93.1%), streptomycin (91.4%), linezolid (91.4%), ceftixozime (87.9%), cloxacillin (86.2%), clotrimazole (86.2%), bacitracin (86.2%), enrofloxacin (84.5%) and ceftrioxone + tazobactum (70.7%), while resistance was observed against amoxicillin (77.6%), penicillin (75.9%), ampicillin (74.1%) and cefoperazone (51.7%). Overall, isolates from clinical cases of mastitis had a higher resistance than subclinical isolates. Conclusion: CNS isolates were susceptible to chloramphenicol, gentamicin and streptomycin, while higher resistance was recorded against routinely used penicillin group.
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Affiliation(s)
- B K Bansal
- Department of Veterinary Medicine, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana - 1410 04, Punjab, India
| | - D K Gupta
- Department of Veterinary Medicine, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana - 1410 04, Punjab, India
| | - T A Shafi
- Department of Veterinary Medicine, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana - 1410 04, Punjab, India
| | - S Sharma
- Department of Veterinary Medicine, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana - 1410 04, Punjab, India
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7
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Zhao JL, Ding YX, Zhao HX, He XL, Li PF, Li ZF, Guan H, Guo X. Presence of superantigen genes and antimicrobial resistance in Staphylococcus
isolates obtained from the uteri of dairy cows with clinical endometritis. Vet Rec 2014; 175:352. [DOI: 10.1136/vr.102302] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- J.-L. Zhao
- Department of Veterinary Pharmacology Toxicology; College of Veterinary Medicine; Inner Mongolia Agricultural University, 306 Zhaowuda Road Hohhot Inner Mongolia Autonomous Region P.R. China
| | - Y.-X. Ding
- Department of Veterinary Pharmacology Toxicology; College of Veterinary Medicine; Inner Mongolia Agricultural University, 306 Zhaowuda Road Hohhot Inner Mongolia Autonomous Region P.R. China
| | - H.-X. Zhao
- Department of Veterinary Pharmacology Toxicology; College of Veterinary Medicine; Inner Mongolia Agricultural University, 306 Zhaowuda Road Hohhot Inner Mongolia Autonomous Region P.R. China
| | - X.-L. He
- Department of Veterinary Pharmacology Toxicology; College of Veterinary Medicine; Inner Mongolia Agricultural University, 306 Zhaowuda Road Hohhot Inner Mongolia Autonomous Region P.R. China
| | - Pei-Feng Li
- Department of Veterinary Pharmacology Toxicology; College of Veterinary Medicine; Inner Mongolia Agricultural University, 306 Zhaowuda Road Hohhot Inner Mongolia Autonomous Region P.R. China
| | - Z.-F. Li
- Department of Veterinary Pharmacology Toxicology; College of Veterinary Medicine; Inner Mongolia Agricultural University, 306 Zhaowuda Road Hohhot Inner Mongolia Autonomous Region P.R. China
| | - H. Guan
- Department of Veterinary Pharmacology Toxicology; College of Veterinary Medicine; Inner Mongolia Agricultural University, 306 Zhaowuda Road Hohhot Inner Mongolia Autonomous Region P.R. China
| | - X. Guo
- Department of Veterinary Pharmacology Toxicology; College of Veterinary Medicine; Inner Mongolia Agricultural University, 306 Zhaowuda Road Hohhot Inner Mongolia Autonomous Region P.R. China
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8
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Klaschik S, Lehmann LE, Steinhagen F, Book M, Molitor E, Hoeft A, Stueber F. Differentiation between Staphylococcus aureus and coagulase-negative Staphylococcus species by real-time PCR including detection of methicillin resistants in comparison to conventional microbiology testing. J Clin Lab Anal 2014; 29:122-8. [PMID: 24796889 DOI: 10.1002/jcla.21739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 12/12/2013] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Staphylococcus aureus has long been recognized as a major pathogen. Methicillin-resistant strains of S. aureus (MRSA) and methicillin-resistant strains of S. epidermidis (MRSE) are among the most prevalent multiresistant pathogens worldwide, frequently causing nosocomial and community-acquired infections. METHODS In the present pilot study, we tested a polymerase chain reaction (PCR) method to quickly differentiate Staphylococci and identify the mecA gene in a clinical setting. RESULTS Compared to the conventional microbiology testing the real-time PCR assay had a higher detection rate for both S. aureus and coagulase-negative Staphylococci (CoNS; 55 vs. 32 for S. aureus and 63 vs. 24 for CoNS). Hands-on time preparing DNA, carrying out the PCR, and evaluating results was less than 5 h. CONCLUSIONS The assay is largely automated, easy to adapt, and has been shown to be rapid and reliable. Fast detection and differentiation of S. aureus, CoNS, and the mecA gene by means of this real-time PCR protocol may help expedite therapeutic decision-making and enable earlier adequate antibiotic treatment.
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Affiliation(s)
- Sven Klaschik
- Department of Anaesthesiology and Intensive Care Medicine, Universitätsklinikum Bonn, Bonn, Germany
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9
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Osbourne D, Aruni AW, Dou Y, Perry C, Boskovic DS, Roy F, Fletcher HM. VimA-dependent modulation of the secretome in Porphyromonas gingivalis. Mol Oral Microbiol 2012; 27:420-35. [PMID: 23134608 DOI: 10.1111/j.2041-1014.2012.00661.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The VimA protein of Porphyromonas gingivalis is a multifunctional protein involved in cell surface biogenesis. To further determine if its acetyl coenzyme A (acetyl-CoA) transfer and putative sorting functions can affect the secretome, its role in peptidoglycan biogenesis and effects on the extracellular proteins of P. gingivalis FLL92, a vimA-defective mutant, were evaluated. There were structural and compositional differences in the peptidoglycan of P. gingivalis FLL92 compared with the wild-type strain. Sixty-eight proteins were present only in the extracellular fraction of FLL92. Fifteen proteins present in the extracellular fraction of the parent strain were missing in the vimA-defective mutant. These proteins had protein sorting characteristics that included a C-terminal motif with a common consensus Gly-Gly-CTERM pattern and a polar tail consisting of aromatic amino acid residues. These observations suggest that the VimA protein is likely involved in peptidoglycan synthesis, and corroborates our previous report, which suggests a role in protein sorting.
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Affiliation(s)
- D Osbourne
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
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10
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The role of antimicrobial peptides in preventing multidrug-resistant bacterial infections and biofilm formation. Int J Mol Sci 2011; 12:5971-92. [PMID: 22016639 PMCID: PMC3189763 DOI: 10.3390/ijms12095971] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 09/05/2011] [Accepted: 09/06/2011] [Indexed: 01/21/2023] Open
Abstract
Over the last decade, decreasing effectiveness of conventional antimicrobial-drugs has caused serious problems due to the rapid emergence of multidrug-resistant pathogens. Furthermore, biofilms, which are microbial communities that cause serious chronic infections and dental plaque, form environments that enhance antimicrobial resistance. As a result, there is a continuous search to overcome or control such problems, which has resulted in antimicrobial peptides being considered as an alternative to conventional drugs. Antimicrobial peptides are ancient host defense effector molecules in living organisms. These peptides have been identified in diverse organisms and synthetically developed by using peptidomimic techniques. This review was conducted to demonstrate the mode of action by which antimicrobial peptides combat multidrug-resistant bacteria and prevent biofilm formation and to introduce clinical uses of these compounds for chronic disease, medical devices, and oral health. In addition, combinations of antimicrobial peptides and conventional drugs were considered due to their synergetic effects and low cost for therapeutic treatment.
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11
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Neves M, Costa J, Vieira V, Abreu I, Lemos M. RESISTÊNCIA AOS ANTIMICROBIANOS E ANÁLISE DA DIVERSIDADE GENÉTICA DE STAPHYLOCOCCUS AUREUS POR PCR-RAPD. ARQUIVOS DO INSTITUTO BIOLÓGICO 2010. [DOI: 10.1590/1808-1657v77p5752010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
RESUMO O objetivo deste trabalho foi analisar a sensibilidade antimicrobiana in vitro de cepas de Staphylococcus aureusisoladas de tetos de vacas e mãos de retireiros, além de verificar o polimorfismo entre elas pela técnica de PCR-RAPD. Os testes foram realizados pela técnica de difusão em discos e, após a extração do material genético foram desenvolvidas as técnicas de PCR e RAPD, usando para isso 40 iniciadores diferentes. A análise do polimorfismo foi realizada empregando-se o programa de taxonomia numérica NTSYS. As sensibilidades dos antimicrobianos nas cepas obtidas de tetos de vacas foram 4% para a penicilina, 88% para a tetraciclina, 92% para a gentamicina, 96% para a vancomicina e 100% ao cloranfenicol. Para as cepas provenientes das mãos de retireiros, os resultados de sensibilidade foram zero para a penicilina, 70% para a tetraciclina e 90% para a vancomicina e 100% para os antimicrobianos gentamicina e cloranfenicol. A realização do E-teste indicou uma concentração inibitória mínima (CIM) maior que 256 mg/mL para as cepas resistentes ao antimicrobiano vancomicina. Os estudos permitiram detectar a resistência dos S. aureus mediante o uso dos antimicrobianos testados e determinar a diversidade genética entre as cepas de estafilococos devido à presença de muitas bandas polimórficas encontradas em todos os iniciadores.
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12
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Osbourne DO, Aruni W, Roy F, Perry C, Sandberg L, Muthiah A, Fletcher HM. Role of vimA in cell surface biogenesis in Porphyromonas gingivalis. MICROBIOLOGY-SGM 2010; 156:2180-2193. [PMID: 20378652 PMCID: PMC3068682 DOI: 10.1099/mic.0.038331-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The Porphyromonas gingivalis vimA gene has been previously shown to play a significant role in the biogenesis of gingipains. Further, in P. gingivalis FLL92, a vimA-defective mutant, there was increased auto-aggregation, suggesting alteration in membrane surface proteins. In order to determine the role of the VimA protein in cell surface biogenesis, the surface morphology of P. gingivalis FLL92 was further characterized. Transmission electron microscopy demonstrated abundant fimbrial appendages and a less well defined and irregular capsule in FLL92 compared with the wild-type. In addition, atomic force microscopy showed that the wild-type had a smoother surface compared with FLL92. Western blot analysis using anti-FimA antibodies showed a 41 kDa immunoreactive protein band in P. gingivalis FLL92 which was missing in the wild-type P. gingivalis W83 strain. There was increased sensitivity to globomycin and vancomycin in FLL92 compared with the wild-type. Outer membrane fractions from FLL92 had a modified lectin-binding profile. Furthermore, in contrast with the wild-type strain, nine proteins were missing from the outer membrane fraction of FLL92, while 20 proteins present in that fraction from FLL92 were missing in the wild-type strain. Taken together, these results suggest that the VimA protein affects capsular synthesis and fimbrial phenotypic expression, and plays a role in the glycosylation and anchorage of several surface proteins.
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Affiliation(s)
- Devon O Osbourne
- Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Wilson Aruni
- Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Francis Roy
- Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Christopher Perry
- Division of Biochemistry, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Lawrence Sandberg
- Division of Biochemistry, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Arun Muthiah
- Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Hansel M Fletcher
- Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
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13
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Schmitz FJ, Fluit AC. Mechanisms of antibacterial resistance. Infect Dis (Lond) 2010. [DOI: 10.1016/b978-0-323-04579-7.00131-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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14
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Moon JS, Lee AR, Kang HM, Lee ES, Kim MN, Paik YH, Park YH, Joo YS, Koo HC. Phenotypic and genetic antibiogram of methicillin-resistant staphylococci isolated from bovine mastitis in Korea. J Dairy Sci 2008; 90:1176-85. [PMID: 17297092 DOI: 10.3168/jds.s0022-0302(07)71604-1] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Staphylococcus aureus belongs to the group of major contagious mastitis pathogens, whereas the coagulase-negative staphylococci (CNS) are also capable of causing opportunistic bovine mastitis. Many of these strains are resistant to penicillin or ampicillin because of the long-term use of beta-lactam antibiotics in agricultural and healthcare settings. Based on the simple and highly specific coagulase genotyping by PCR-RFLP used for discriminating among Staph. aureus strains, the relationship between phenotypic antibiogram and the polymorphism of coagulase gene was determined in this study. The staphylococci strains (835 Staph. aureus and 763 CNS) were isolated from 3,047 bovine mastitic milk samples from 153 dairy farms in 8 provinces from 1997 to 2004 in the Republic of Korea. Twenty-one (2.5%) Staph. aureus and 19 (2.4%) CNS strains were resistant to methicillin [oxacillin minimum inhibitory concentration (MIC) > or = 4 microg/mL]. The mecA gene was also found in 13 methicillin-resistant Staph. aureus (MRSA) and 12 methicillin-resistant CNS (MRCNS) isolates with a significantly higher detection rate of the mecA gene in MRSA with high MIC (> or = 16 microg/mL) compared with those with MIC < or = 8 microg/mL. Methicillin-resistant Staph. aureus and MRCNS were also more resistant to other antibiotics (ampicillin, cephalothin, kanamycin, and gentamicin) than methicillin-susceptible staphylococci. Among 10 different coa PCR-RFLP patterns (A to J) in 706 Staph. aureus strains, the main types were A (26.9%), B (17.0%), G (10.5%), and H (15.4%), with the frequent observation of the A and H types (6 and 10 isolates) in MRSA. This study indicates that major epidemic Staph. aureus clones may be spread between different dairy farms, and the profile of coa genotype can be applied for epidemiological investigations and control of bovine mastitis, particularly one caused by MRSA with specific prevalent coa types.
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Affiliation(s)
- J-S Moon
- Department of Bacteriology, National Veterinary Research and Quarantine Service, Anyang, Gyeonggi-do, Republic of Korea
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Neves M, Rossi Junior O, Alves E, Lemos M. DETECÇÃO DE GENES DE RESISTÊNCIA ANTIMICROBIANA EM CROMOSSOMOS E PLASMÍDEOS DE STAPHYLOCOCCUS SPP. ARQUIVOS DO INSTITUTO BIOLÓGICO 2007. [DOI: 10.1590/1808-1657v74p2072007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
RESUMO Este trabalho teve por objetivo analisar o uso da prensa francesa para se adquirir material genético de estafilococos e detectar possíveis genes de resistência cromossomais e plasmidiais aos antimicrobianos oxacilina, gentamicina, canamicina e vancomicina. O método da difusão de discos em ágar foi realizado, inicialmente, para 50 linhagens de estafilococos e a susceptibilidade antimicrobiana foi confirmada por meio de Reação em Cadeia da Polimerase (PCR). Os resultados obtidos pelo antibiograma constataram alta susceptibilidade para gentamicina e canamicina (4%) e oxacilina (8%). Todas as linhagens foram susceptíveis à vancomicina. O DNA bacteriano foi obtido por lise física a partir da prensa francesa. Os genes mecA e aph3’IIIa foram detectados no cromossomo dos estafilococos e o gene aac(6’) Ie + aph (2") foi observado tanto no cromossomo como no plasmidio destas bactérias. Pelos resultados pode-se concluir que a metodologia utilizada para a extração de DNA genômico, por meio da prensa francesa, foi barata e eficiente, pois possibilitou a detecção por PCR e a localização, por ultracentrifugação, de genes de resistência em estafilococos.
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Meng J, Hu B, Liu J, Hou Z, Meng J, Jia M, Luo X. Restoration of oxacillin susceptibility in methicillin-resistant Staphylococcus aureus by blocking the MecR1-mediated signaling pathway. J Chemother 2006; 18:360-5. [PMID: 17024790 DOI: 10.1179/joc.2006.18.4.360] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The signal transducing integral membrane protein, MecR1 helps initiate the expression of the antibiotic-resistant gene mecA, which encodes the penicillin-binding protein 2a. MecA participates in the beta-lactam resistance of methicillin-resistant Staphylococcus aureus (MRSA). Blocking the MecR1 regulatory pathway may be a novel strategy to combat MRSA. In this study, we introduced an antisense phosphothioate oligodeoxynucleotide (PS-ODN) targeting MecR1 mRNA into the MRSA strain WHO-2, which led to a significant reduction of both MecR1 and PBP2a mRNAs in a concentration-dependent manner. Consequently, the susceptibility of S. aureus WHO-2 to the beta-lactam antibiotic oxacillin was restored significantly. Our results indicate that blocking the mecR1-mecI-mecA signaling pathway via an antisense approach might be a viable strategy to restore the susceptibility of MRSA to the existing beta-lactam antibiotics.
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Affiliation(s)
- Jingru Meng
- Department of Pharmacology, The Fourth Military Medical University, 17 Changle West Rd., Xi'an 710032, PR China
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Campoccia D, Montanaro L, Arciola CR. The significance of infection related to orthopedic devices and issues of antibiotic resistance. Biomaterials 2005; 27:2331-9. [PMID: 16364434 DOI: 10.1016/j.biomaterials.2005.11.044] [Citation(s) in RCA: 672] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2005] [Accepted: 11/28/2005] [Indexed: 12/24/2022]
Abstract
Over the last 15 years, with the advent of modern standards in the control of sterility within the operating room environment and adequate protocols of peri-operative antibiotic prophylaxis, the incidence of infections associated to orthopedic implants has become very low. Nevertheless, the event of infection still represents one of the most serious and devastating complications which may involve prosthetic devices. It leads to complex revision procedures and, often, to the failure of the implant and the need for its complete removal. In orthopedics, for the enormous number of surgical procedures involving invasive implant materials, even if nowadays rare, infections have a huge impact in terms of morbidity, mortality, and medical costs. The difficult battle to prevent and fight bacterial infections associated to prosthetic materials must be played on different grounds. A winning strategy requires a clear view of the pathogenesis and the epidemiology of implant-related infections, with a special attention on the alarming phenomenon of antibiotic resistance. In this regard staphylococci are the prevalent and most important causative pathogens involved in orthopedic implant-related infections, and, thus, the main enemy to defeat. In this paper, we offer an overview of the complexity of this battleground and of the current and new, in our opinion most promising, strategies in the field of biomaterials to reduce the risks and counteract the establishment of implant infections.
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Affiliation(s)
- Davide Campoccia
- Research Unit on Implant Infections, Rizzoli Orthopedic Institute, Via di Barbiano, 1/10, 40136 Bologna, Italy
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Kaszanyitzky EJ, Jánosi S, Egyed Z, Agost G, Semjén G. Antibiotic resistance of staphylococci from humans, food and different animal species according to data of the Hungarian resistance monitoring system in 2001. Acta Vet Hung 2004; 51:451-64. [PMID: 14680057 DOI: 10.1556/avet.51.2003.4.3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Based on data of the Hungarian resistance monitoring system the antibiotic resistance of Staphylococcus strains of human and animal origin was studied. No methicillin-resistant staphylococci harbouring mecA gene were isolated from animals in 2001. Penicillin resistance, mediated by penicillinase production, was the most frequent among Staphylococcus aureus strains isolated from humans (96%), from bovine mastitis (55%), from foods (45%) and from dogs. In staphylococci isolated from animals low resistance percentages to aminoglycosides (0-2%), fluoroquinolones (0.5-3%) and sulphonamides (0.5-4%) were found but in strains isolated humans these figures were higher (1-14%, 5-18% and 3-31%, respectively). The most frequent antibiotic resistance profiles of strains isolated from animals and food were penicillin/tetracycline, penicillin/lincomycin and penicillin/lincomycin/tetracycline. Penicillin/tetracycline resistance was exhibited by strains from mastitis (3), samples from the meat industry (31), poultry flocks (1), poultry industry (1), noodle (1) and horses (2). Penicillin/lincomycin resistance was found in 10 Staphylococcus strains from mastitis, 1 from the dairy industry, 1 from the meat industry and 6 from dogs. Isolates from mastitis (2), from the dairy industry (2), from pigs (1), from the meat industry (1) and from poultry (1) harboured penicillin/lincomycin/tetracycline resistance pattern. Multiresistant strains were usually isolated only from one and sometimes from two animal species; therefore, the spread of defined resistant strains (clones) among different animal species could not be demonstrated. These results also suggest that the transfer of antibiotic resistance of S. aureus from animals to humans probably occurs less frequently than is generally assumed.
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Kaszanyitzky EJ, Egyed Z, Jánosi S, Keseru J, Gál Z, Szabó I, Veres Z, Somogyi P. Staphylococci isolated from animals and food with phenotypically reduced susceptibility to beta-lactamase-resistant beta-lactam antibiotics. Acta Vet Hung 2004; 52:7-17. [PMID: 15119783 DOI: 10.1556/avet.52.2004.1.2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The antibiotic resistance pattern of 1921 Staphylococcus strains isolated from animals and food within the last two years were examined using diffusion tests. Among them there were only 35 strains of S. aureus having an inhibition zone diameter of 15 mm or less, and 4 strains of coagulase-negative staphylococci (CNS) having a zone diameter of 18 mm or less to 1-microg oxacillin disk. These 39 strains were examined also by E-test to oxacillin and for the detection of the mecA gene by PCR in order to determine whether they might be real methicillin-resistant staphylococci. Among the 39 strains there were only two that were susceptible to penicillin by disk diffusion method; however, further examination by the penicillinase test showed that they produced beta-lactamase. While 19 (15 S. aureus, 4 CNS) strains were resistant and 7 strains were intermediate to oxacillin in disk diffusion test, the E-test gave 8 resistant and 5 intermediate results. Six out of the 8 oxacillin-resistant strains examined by disk diffusion and E-test harboured the mecA gene. Thus only 6 out of the examined 1921 strains proved to be mecA positive. These methicillin-resistant, mecA-positive strains (5 of the S. aureus strains and 1 of the S. epidermidis) originated from two dairy herds. The results prove that methicillin-resistant S. aureus (MRSA) strains in animals are really rare in Hungary. Eighteen strains were chosen and screened for minimal inhibitory concentration (MIC) of oxacillin with or without clavulanic acid or sulbactam, and three of them produced methicillinase enzyme.
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Kampf G, Adena S, Rüden H, Weist K. Inducibility and potential role of MecA-gene-positive oxacillin-susceptible Staphylococcus aureus from colonized healthcare workers as a source for nosocomial infections. J Hosp Infect 2003; 54:124-9. [PMID: 12818586 DOI: 10.1016/s0195-6701(03)00119-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To determine the carrier rate of methicillin-susceptible mecA-positive Staphylococcus aureus (dormant MRSA) among healthcare workers (HCWs), 447 nurses and physicians from 13 general wards and intensive care units were investigated for nasal or oropharyngeal S. aureus carriage during one year whenever an MRSA patient was treated. Induction of phenotypic resistance in all mecA-positive oxacillin-susceptible aureus was attempted by 24 h exposure to oxacillin and cefotaxime. Organisms from the broth tube with the highest antibiotic concentration and visible growth after incubation were re-exposed for a total of seven repetitive exposures. Two mecA-negative oxacillin-susceptible S. aureus served as negative control. A population analysis before and after antibiotic exposure was performed. A third of the HCWs were found to be S. aureus carriers. Only three nurses were MRSA positive (0.7%). Seven isolates of dormant MRSA were isolated in six nurses and one doctor (1.6%). After four days of repetitive antibiotic exposure six of seven dormant MRSA were highly resistant to oxacillin. Resistance of the two control S. aureus without the mecA gene was not changed by repetitive antibiotic exposure. Two of the seven dormant MRSA were clonally related as shown by pulsed-field gel electrophoresis (PFGE). The PFGE pattern of one dormant MRSA (HCW) was identical to an MRSA (HCW). The pattern of another dormant MRSA was indistinguishable from an MRSA isolated from a patient who was treated at the same time on the same ward suggesting transmission from the HCW to the patient. Dormant MRSA may be isolated twice as often as MRSA from HCWs. Transmission to patients is possible, which may lead to clinical infections. It might be useful to screen methicillin-susceptible S. aureus isolates from HCWs for the mecA gene when recurrent infections with MRSA occur on a ward and a source cannot be found.
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Affiliation(s)
- G Kampf
- Institute of Hygiene, University Hospital Benjamin Franklin, Free University Berlin, Berlin, Germany
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21
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Moore JE, Millar BC, Crowe M, Buchanan J, Watabe M, Murphy PG, Yongmin X, Milligan K, McClelland A. Molecular determination of carriage of the mecA locus in coagulase negative staphylococci in screening swabs from patients in an intensive care unit. Mol Pathol 2003; 56:63. [PMID: 12560467 PMCID: PMC1187293 DOI: 10.1136/mp.56.1.63] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- J E Moore
- Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast BT9 7AD, Northern Ireland, UK;
| | - B C Millar
- Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast BT9 7AD, Northern Ireland, UK;
| | - M Crowe
- Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast BT9 7AD, Northern Ireland, UK;
| | - J Buchanan
- Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast BT9 7AD, Northern Ireland, UK;
| | - M Watabe
- Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast BT9 7AD, Northern Ireland, UK;
| | - P G Murphy
- Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast BT9 7AD, Northern Ireland, UK;
| | - X Yongmin
- Department of Biochemistry, Xian Medical University, Xian, Shaanxi Province, The People’s Republic of China
| | - K Milligan
- Department of Intensive Care Medicine, Belfast City Hospital, Belfast BT9 7AB, Northern Ireland, UK
| | - A McClelland
- Department of Intensive Care Medicine, Belfast City Hospital, Belfast BT9 7AB, Northern Ireland, UK
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Ginsburg I. The role of bacteriolysis in the pathophysiology of inflammation, infection and post-infectious sequelae. APMIS 2002; 110:753-70. [PMID: 12588416 DOI: 10.1034/j.1600-0463.2002.1101101.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The literature dealing with the biochemical basis of bacteriolysis and its role in inflammation, infection and in post-infectious sequelae is reviewed and discussed. Bacteriolysis is an event that may occur when normal microbial multiplication is altered due to an uncontrolled activation of a series of autolytic cell-wall breaking enzymes (muramidases). While a low-level bacteriolysis sometimes occurs physiologically, due to "mistakes" in cell separation, a pronounced cell wall breakdown may occur following bacteriolysis induced either by beta-lactam antibiotics or by a large variety of bacteriolysis-inducing cationic peptides. These include spermine, spermidine, bactericidal peptides defensins, bacterial permeability increasing peptides from neutrophils, cationic proteins from eosinophils, lysozyme, myeloperoxidase, lactoferrin, the highly cationic proteinases elastase and cathepsins, PLA2, and certain synthetic polyamino acids. The cationic agents probably function by deregulating lipoteichoic acid (LTA) in Gram-positive bacteria and phospholipids in Gram-negative bacteria, the presumed regulators of the autolytic enzyme systems (muramidases). When bacteriolysis occurs in vivo, cell-wall- and -membrane-associated lipopolysaccharide (LPS (endotoxin)), lipoteichoic acid (LTA) and peptidoglycan (PPG), are released. These highly phlogistic agents can act on macrophages, either individually or in synergy, to induce the generation and release of reactive oxygen and nitrogen species, cytotoxic cytokines, hydrolases, proteinases, and also to activate the coagulation and complement cascades. All these agents and processes are involved in the pathophysiology of septic shock and multiple organ failure resulting from severe microbial infections. Bacteriolysis induced in in vitro models, either by polycations or by beta-lactams, could be effectively inhibited by sulfated polysaccharides, by D-amino acids as well as by certain anti-bacteriolytic antibiotics. However, within phagocytic cells in inflammatory sites, bacteriolysis tends to be strongly inhibited presumably due to the inactivation by oxidants and proteinases of the bacterial muramidases. This might results in a long persistence of non-biodegradable cell-wall components causing granulomatous inflammation. However, persistence of microbial cell walls in vivo may also boost innate immunity against infections and against tumor-cell proliferation. Therapeutic strategies to cope with the deleterious effects of bacteriolysis in vivo include combinations of autolysin inhibitors with combinations of certain anti-inflammatory agents. These might inhibit the synergistic tissue- and- organ-damaging "cross talks" which lead to septic shock and to additional post-infectious sequelae.
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Affiliation(s)
- Isaac Ginsburg
- Department of Oral Biology, Hebrew University, Hadassah Faculty of Dental Medicine, Jerusalem, Israel.
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Abstract
There is an urgent need for fresh approaches to the treatment of bacterial infections because of the changing patterns of infectious disease and the emergence of bacterial strains resistant to current antibiotics. Modification of the cell phenotype to sensitize bacteria to components of the hosts' immune system or to previously ineffective antibiotics could prevent the emergence of the resistant genotype. In addition, the use of light-activated antibacterial agents and lytic bacteriophage specific for key pathogens should be considered as safe and inexpensive alternatives to conventional treatment regimens for certain non-systemic infections.
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Affiliation(s)
- Peter W Taylor
- Department of Pharmaceutics, School of Pharmacy, University of London, 29-39 Brunswick Square, London, UK WC1N 1AX.
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Bogado I, Sutich E, Krapp A, Marchiaro P, Marzi M, Putero J, Carrillo N. Methicillin resistance study in clinical isolates of coagulase-negative staphylococci and determination of their susceptibility to alternative antimicrobial agents. J Appl Microbiol 2001; 91:344-50. [PMID: 11473600 DOI: 10.1046/j.1365-2672.2001.01400.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To achieve reliable detection of methicillin resistance in clinical isolates of coagulase-negative staphylococci. METHODS AND RESULTS Strains (105) were evaluated by normatized antimicrobial susceptibility methods, and for the presence of the methicillin resistance-determining mecA gene, using the polymerase chain reaction. Correlation between phenotypic and genotypic methods was obtained in 87.6% of the samples. Six strains, classified as methicillin-susceptible by phenotypic assays, revealed the presence of the mecA gene, indicating that methicillin resistance expression was probably repressed. Another seven isolates failed to show mecA amplification after displaying methicillin resistance in phenotypic evaluations. The susceptibility of the methicillin-resistant isolates to other antimicrobial agents was variable. CONCLUSION Genotypic determination of the mecA gene proved to be the most reliable method for detection of methicillin resistance. SIGNIFICANCE AND IMPACT OF THE STUDY Correct assessment of methicillin resistance, such as that attained through genotyping, is essential for defining therapeutic strategies, particularly when treating severely compromised patients.
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Affiliation(s)
- I Bogado
- Department of Microbiology, School of Biochemistry and Pharmacy, National University of Rosario, Rosario, Argentina.
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Yazdankhah SP, Sørum H, Oppegaard H. Comparison of genes involved in penicillin resistance in staphylococci of bovine origin. Microb Drug Resist 2000; 6:29-36. [PMID: 10868805 DOI: 10.1089/mdr.2000.6.29] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ten penicillin-resistant and -susceptible staphylococci, isolated from bovine mastitis milk, were studied for the presence of genes that are, or may be, involved in resistance against penicillin. The repressor (blaI), antirepressor (blaR1), and structural (blaZ) genes of the beta-lactamase-operon were found to be closely linked in all penicillin-resistant strains. The beta-lactamase gene cluster was more commonly located on chromosomal rather than plasmid DNA in the strains studied. The transposase (p480) gene, which has been identified in the Staphylococcus aureus beta-lactamase transposon Tn552, was found in only one single penicillin-resistant S. aureus strain. The other penicillin-resistant S. aureus isolates contained IS1181 in close location with the beta-lactamase gene cluster. In only one S. haemolyticus isolate was the beta-lactamase gene cluster found in close association with IS257. Penicillin-resistant S. aureus strains, which were additionally resistant to tetracycline, contained IS257 in close association with the tetracycline resistance gene (tetK). Sequence analysis of blaI, blaR1, and blaZ in two penicillin-resistant S. aureus strains revealed 94-96% sequence homology with bla in staphylococci of human origin. The results indicate a predominance of class I bla transposons rather than Tn3 family class II transposons in the isolates used in this study.
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Affiliation(s)
- S P Yazdankhah
- Department of Pharmacology, Microbiology and Food Hygiene, Norwegian School of Veterinary Science, Oslo.
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Hoiby N, Pers C, Johansen HK, Hansen H. Excretion of beta-lactam antibiotics in sweat--a neglected mechanism for development of antibiotic resistance? Antimicrob Agents Chemother 2000; 44:2855-7. [PMID: 10991872 PMCID: PMC90163 DOI: 10.1128/aac.44.10.2855-2857.2000] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The concentrations of beta-lactam antibiotics after standard doses were measured in blood and apocrine (axilla) and eccrine (forearm) sweat from six adult healthy persons. All persons had ceftazidime (axilla, 28.4 microg/ml; forearm, 11 microg/ml) and ceftriaxone (axilla, 8.9 microg/ml; forearm, 2.5 microg/ml) in sweat, and one person had cefuroxime in sweat (axilla, 7.8 microg/ml) (all data are mean peaks). Three persons had benzylpenicillin (axilla, 2.6 to 0.1 microg/ml) and one had phenoxymethylpenicillin (axilla, 0.4 microg/ml) in sweat. Excretion of beta-lactam antibiotics in the sweat may explain why staphylococci so rapidly become resistant to these drugs.
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Affiliation(s)
- N Hoiby
- Department of Clinical Microbiology, Rigshospitalet, University of Copenhagen, Denmark.
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Szewczyk EM, Piotrowski A, Rózalska M. Predominant staphylococci in the intensive care unit of a paediatric hospital. J Hosp Infect 2000; 45:145-54. [PMID: 10860691 DOI: 10.1053/jhin.1999.0754] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Coagulase-negative staphylococci cause a significant number of infections, especially in immunocompromised patients, including premature neonates. Nosocomial strains present in the environment create a special risk.We studied staphylococci isolated from the intensive care unit of a paediatric teaching hospital over the period of six months in 1997. Biotyping and species identification were performed; resistance to methicillin and other beta-lactam antibiotics and patterns of resistance to antimicrobial agents were determined. Staphylococcus cohnii was the predominant species of 147 isolates of staphylococci recovered from the ward environment. Strains were resistant to several antibiotics and 97% were resistant to methicillin. In isolates from infants (72) methicillin-resistant strains of Staphylococcus epidermidis were predominant. Susceptibility to beta-lactams (penicillin, amoxycillin, amoxycillin-clavulanic acid and cephalosporins: cephalothin, cefuroxime and cefotaxime) showed differences between the two species. Some S. cohnii were susceptible to penicillin and amoxycillin despite methicillin-resistance. S. epidermidis were relatively susceptible to amoxycillin-clavulanic acid and cephalosporins. All strains investigated were susceptible to vancomycin, but nearly 30% demonstrated high-level resistance to mupirocin. The search for strains of the same origin showed clones belonging to S. epidermidis, S. hominis and S. saprophyticus but not S. cohnii.A large number of multiresistant, phenotypically different S. cohnii strains surviving in the ward environment may provide a reservoir of antimicrobial resistance genes.
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Affiliation(s)
- E M Szewczyk
- Department of Pharmaceutical Microbiology, Medical University of Lódź.
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Lewis RA, Dyke KG. MecI represses synthesis from the beta-lactamase operon of Staphylococcus aureus. J Antimicrob Chemother 2000; 45:139-44. [PMID: 10660494 DOI: 10.1093/jac/45.2.139] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Plasmid diploids were constructed in Staphylococcus aureus to study the effect of the repressor of methicillin resistance (MecI) on the synthesis of both beta-lactamase and the beta-lactamase repressor (BlaI). MecI-mediated repression of the synthesis of beta-lactamase was shown by reduction in the specific activity of nitrocefinase in bacteria containing a plasmid carrying mecI but not when containing the same plasmid deleted for mecI. Antisera prepared against purified MecI and against purified BlaI were used in Western blots which showed that MecI repressed the synthesis of BlaI in these diploids. The interactions between the mec operon and the bla operon are discussed.
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Affiliation(s)
- R A Lewis
- University of Oxford, Microbiology Unit, Department of Biochemistry, South Parks Road, Oxford OX1 3QU, UK
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Jafri AK, Reisner BS, Woods GL. Evaluation of a latex agglutination assay for rapid detection of oxacillin resistant Staphylococcus aureus. Diagn Microbiol Infect Dis 2000; 36:57-9. [PMID: 10744369 DOI: 10.1016/s0732-8893(99)00105-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oxacillin resistance in Staphylococcus aureus is mediated by the mecA gene, resulting in production of penicillin-binding protein 2a (PBP2a), which is not present in the oxacillin susceptible strains. We evaluated the ability of a 30-min latex agglutination (LA) test (Seiken, Tokyo, Japan) to detect production of PBP2a in 315 clinical isolates of S. aureus. The LA results were compared with results of susceptibility testing using the Vitek GPS-SV test card. The latex test was positive for all 206 isolates determined to be methicillin resistant by Vitek (sensitivity 100%), the latex test was negative for 108 of 109 isolates determined to be oxacillin susceptible by Vitek, and the latex test was positive for 1 isolate determined to be susceptible by Vitek (specificity 99.1%). The discrepant isolate was negative for the mecA gene by polymerase chain reaction (PCR). The LA test is a rapid and reliable method for detecting oxacillin resistant S. aureus.
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Affiliation(s)
- A K Jafri
- Department of Pathology, University of Texas Medical Branch, Galveston 77555-0740, USA
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Abstract
With the completion of numerous bacterial genome sequences, the discovery of antibacterial drugs has fully entered the genomic era. The strategies for effectively using genomic information for target identification, target characterization, screen development and compound evaluation are emerging, and have greatly increased the number of antibacterial targets available for screening. Fortunately, simultaneous efforts in improving miniaturization, robotics and database tools are underway so that the potential of genomics can be realized.
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Affiliation(s)
- M B Schmid
- Microcide Pharmaceuticals Inc, Mountain View, CA 94043, USA.
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32
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Antimicrobial Potentiation Approaches: Targets and Inhibitors. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1998. [DOI: 10.1016/s0065-7743(08)61077-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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