Factors influencing methicillin resistance in staphylococci

Berger‐Bächi, Brigitte; Rohrer, Susanne

doi:10.1007/s00203-002-0436-0

Cited by 240 publications

(171 citation statements)

References 47 publications

Supporting

Mentioning

164

Contrasting

Unclassified

Order By: Relevance

“…PBP 2′a plays an important role in catalyzing the transpeptidational activity which is crucial for the cross-linkage of peptidoglycan. 18 This may mean that MRSA actually has a more permeable cell wall than the S. aureus naïve strain. The altered architectural structure in MRSA may therefore favor the penetration of pL-ce6 and TBO across the cell wall, resulting in the higher killing of MRSA upon illumination.…”

Section: Discussionmentioning

confidence: 99%

A comparative in vitro photoinactivation study of clinical isolates of multidrug-resistant pathogens

Tang

Hamblin

Yow

2007

Journal of Infection and Chemotherapy

View full text Add to dashboard Cite

Photodynamic inactivation (PDI) has been investigated to cope with the increasing incidence of multidrug-resistant (MDR) pathogens. In Hong Kong, methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase (ESBL)-producing Escherichia coli are the two commonest MDR pathogens. Here, we studied the photodynamic inactivation (PDI) mediated by poly-L-lysine chlorin(e6) conjugate (pL-ce6) and toluidine blue O (TBO) in clinical MRSA and ESBL producing E. coli, together with their corresponding American Type Culture Collection (ATCC) strains. Both pL-ce6 and TBO mediated a light-and drug dose-dependent efficacy for the four pathogens. pL-ce6 was more effective. pL-ce6 at 8 µM, 30 Jcm −2 , attained 5 log killing for ESBL-producing E. coli and E. coli (ATCC 25922); 4 log killing for MRSA, and 3 log killing for S. aureus (ATCC 25923). TBO at 80 µM, 30 Jcm −2 , only exhibited 3 log killing in MRSA and 2 log killing in S. aureus (ATCC 25923). TBO (400 µM, 30 Jcm −2 ) induced equal killing for ESBLproducing E. coli and E. coli (ATCC 25922). Our studied MRSA isolate responded better than S. aureus (ATCC 25923). Thus, pL-ce6-mediated PDI in other MRSA isolates deserves further investigation.

show abstract

Section: Discussionmentioning

confidence: 99%

A comparative in vitro photoinactivation study of clinical isolates of multidrug-resistant pathogens

Tang

Hamblin

Yow

2007

Journal of Infection and Chemotherapy

View full text Add to dashboard Cite

show abstract

“…MRSA strains were first described in England in 1961; most MRSA infections are acquired in hospitals (HA-MRSA) or long-term care facilities (LTCFs). MRSA has been acquired in the community (CA-MRSA) by intravenous drug users in few cities [19,10].…”

Section: Introductionmentioning

confidence: 99%

“…PBP2a is located in the bacterial cell wall and has a low binding affinity for β-lactams, which is not present in methicillinsusceptible S. aureus (MSSA) [7,19]. femAgene is implicated in cell wall metabolism and is found in large amounts in actively growing cultures [10].…”

Section: Introductionmentioning

confidence: 99%

Detection and Evaluation of Methicillin-Resistant Staphylococcus aureus by Duplex PCR

Kareem

2013

JNUS

View full text Add to dashboard Cite

Staphylococcusaureusis avirulence pathogenic bacterium.Detection of methicillin-resistant S. aureus(MRSA) using conventional culture and biochemical methods is labor and time consuming. Many MRSA isolates are heterogeneously resistant to ß-lactams, for example only 1 daughter cell out of 10 4 to 10 6 cells appears phenotypically resistant when routine antimicrobial susceptibility tests are performed. In this work two genes were used for detection of MRSA in urine, boil and nasal swabs using conventional PCR, mecA gene (533bp) were used for detection of methicillin resistant and femA gene (318bp) were used for S.aureus identification. It was found that not all resistant S. aureus tested with disk diffusion method carry the mecA gene that caused the resistant phenomena there were only 55% of all MRSA carrying mecA gene while femA gene gave 100% positive for S. aureus and this will lead us to appoint that penicillin-bindingprotein 2a (PBP2a) produced by mecA gene is not the only cause of resistant phenomena.

show abstract

“…It has been suggested that PBP2a takes over the biosynthesis of peptidoglycan in the presence of otherwise lethal doses of ␤-lactam antibiotics (16). Several studies have demonstrated that additional factors are involved in the expression of high and homogeneous methicillin resistance levels in methicillinresistant S. aureus (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). A few of these additional factors, notably the proteins encoded by the fem genes, have been characterized functionally (17,30,31).…”

mentioning

confidence: 99%

“…Several studies have demonstrated that additional factors are involved in the expression of high and homogeneous methicillin resistance levels in methicillinresistant S. aureus (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). A few of these additional factors, notably the proteins encoded by the fem genes, have been characterized functionally (17,30,31). Among the identified methicillin resistance factors, fmtA in particular has been reported to be part of the cell wall stimulon (32)(33)(34)(35), which is a group of genes that is commonly induced upon treatment with cell wallactive antibiotics, such as ␤-lactams.…”

mentioning

confidence: 99%

Diversity of Penicillin-binding Proteins

Xin

Liu

Smith

et al. 2007

Journal of Biological Chemistry

View full text Add to dashboard Cite

Antibiotic-resistant Staphylococcus aureus is a major concern to public health. Methicillin-resistant S. aureus strains are completely resistant to all ␤-lactams antibiotics. One of the main factors involved in methicillin resistance in S. aureus is the penicillin-binding protein, PBP2a. This protein is insensitive to inactivation by ␤-lactam antibiotics such as methicillin. Although other proteins are implicated in high and homogeneous levels of methicillin resistance, the functions of these other proteins remain elusive. Herein, we report for the first time on the putative function of one of these proteins, FmtA. This protein specifically interacts with ␤-lactam antibiotics forming covalently bound complexes. The serine residue present in the sequence motif Ser-X-X-Lys (which is conserved among penicillin-binding proteins and ␤-lactamases) is the active-site nucleophile during the formation of acyl-enzyme species. FmtA has a low binding affinity for ␤-lactams, and it experiences a slow acylation rate, suggesting that this protein is intrinsically resistant to ␤-lactam inactivation. We found that FmtA undergoes conformational changes in presence of ␤-lactams that may be essential to the ␤-lactam resistance mechanism. FmtA binds to peptidoglycan in vitro. Our findings suggest that FmtA is a penicillin-binding protein, and as such, it may compensate for suppressed peptidoglycan biosynthesis under ␤-lactam induced cell wall stress conditions.

show abstract

Factors influencing methicillin resistance in staphylococci

Cited by 240 publications

References 47 publications

A comparative in vitro photoinactivation study of clinical isolates of multidrug-resistant pathogens

A comparative in vitro photoinactivation study of clinical isolates of multidrug-resistant pathogens

Detection and Evaluation of Methicillin-Resistant Staphylococcus aureus by Duplex PCR

Diversity of Penicillin-binding Proteins

Contact Info

Product

Resources

About