Inactivated pbp4 in Highly Glycopeptide-resistant Laboratory Mutants of Staphylococcus aureus

Sieradzki, Krzysztof; Pinho, Mariana G.; Tomasz, Alexander

doi:10.1074/jbc.274.27.18942

Cited by 126 publications

(124 citation statements)

References 25 publications

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“…Briefly, mutanolysin-digested peptidoglycan was separated by reversed-phase high pressure liquid chromatography for muropeptide analysis. Glycan chain analysis was performed according to the method for muropeptide analysis except that the cell wall was digested with lysostaphin instead of mutanolysin as previously described (20). For control purposes, some samples were also doubly digested with both enzymes.…”

Section: Methodsmentioning

confidence: 99%

“…To further characterize the cell surface structure of the atl null mutant, we prepared peptidoglycan from the wild type RN4220 and the mutant JT1392, and the enzymatic hydrolysates obtained by digestion with either mutanolysin (to analyze muropeptide composition) or lysostaphin (to detect possible alterations in sugar chain length distribution) were analyzed by high pressure liquid chromatography (20,21). Double digestions with both enzymes were analyzed as a control for completeness of enzymatic degradation.…”

Section: Cell Wallmentioning

confidence: 99%

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Molecular Characterization of an atl Null Mutant of Staphylococcus aureus

Takahashi

Komatsuzawa

Yamada

et al. 2002

Microbiology and Immunology

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atl is a gene encoding a bifunctional peptidoglycan hydrolase of Staphylococcus aureus. The gene product of atl is a 138 kDa protein that has an amidase domain and a glucosaminidase domain, and undergoes processing to generate two major peptidoglycan hydrolases, a 51 kDa glucosaminidase and a 62 kDa amidase in culture supernatant. An atl null mutant was isolated by allelic replacement and characterized. The mutant grew in clusters and sedimented when grown in broth culture. Analysis of peptidoglycan prepared from the wild type and the mutant revealed that there were no differences in muropeptide composition or in glycan chain length distribution. On the other hand, the atl mutation resulted in pleiotropic effects on cell surface nature. The mutant cells showed complete inhibition of metabolic turnover of cell wall peptidoglycan and revealed a rough outer cell wall surface. The mutation also decreased the amount of protein non‐covalently bound to the cell surface and altered the protein profile, but did not affect proteins covalently associated with the cell wall. Lysis of growing cells treated with otherwise lytic concentration of penicillin G was completely inhibited in the mutant, but that of non‐growing cells was not affected by the mutation. The atl mutation did not significantly affect the ability of S. aureus to provoke an acute infection when inoculated intraperitoneally in a mouse sepsis model. These results further support the supposition that atl gene products are involved in cell separation, cell wall turnover and penicillin‐induced lysis of the cells.

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Section: Methodsmentioning

confidence: 99%

Section: Cell Wallmentioning

confidence: 99%

Molecular Characterization of an atl Null Mutant of Staphylococcus aureus

Takahashi

Komatsuzawa

Yamada

et al. 2002

Microbiology and Immunology

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“…In the late 1990s, Sieradzki et al suggested that alterations in cell wall structure inhibit vancomycin access to its active site in a laboratory-induced strain with a vancomycin MIC of 100 g per ml (315,320). Over recent years, a model of the resistance mechanism of hVISA and VISA has evolved, where VISA emerges by sequential mutations from VSSA, with hVISA as an intermediary between VSSA and VISA.…”

Section: Phenotypic Features and Mechanisms Of Resistancementioning

confidence: 99%

Reduced Vancomycin Susceptibility inStaphylococcus aureus, Including Vancomycin-Intermediate and Heterogeneous Vancomycin-Intermediate Strains: Resistance Mechanisms, Laboratory Detection, and Clinical Implications

et al. 2010

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SUMMARY The emergence of vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) over the past decade has provided a challenge to diagnostic microbiologists to detect these strains, clinicians treating patients with infections due to these strains, and researchers attempting to understand the resistance mechanisms. Recent data show that these strains have been detected globally and in many cases are associated with glycopeptide treatment failure; however, more rigorous clinical studies are required to clearly define the contribution of hVISA to glycopeptide treatment outcomes. It is now becoming clear that sequential point mutations in key global regulatory genes contribute to the hVISA and VISA phenotypes, which are associated predominately with cell wall thickening and restricted vancomycin access to its site of activity in the division septum; however, the phenotypic features of these strains can vary because the mutations leading to resistance can vary. Interestingly, changes in the staphylococcal surface and expression of agr are likely to impact host-pathogen interactions in hVISA and VISA infections. Given the subtleties of vancomycin susceptibility testing against S. aureus, it is imperative that diagnostic laboratories use well-standardized methods and have a framework for detecting reduced vancomycin susceptibility in S. aureus.

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“…These studies have led to a model of vancomycin resistance in which decreased cell wall turnover and autolysis result in increased cell wall thickness and resistance to vancomycin. Mechanistically, the thickened cell wall is thought to limit the access of vancomycin to its target (6,9,11,12,26). Because this model of vancomycin resistance relies on an alteration in cell wall thickness, most research has focused on adaptations affecting cell wall thickening.…”

mentioning

confidence: 99%

Vancomycin-Intermediate Staphylococcus aureus Strains Have Impaired Acetate Catabolism: Implications for Polysaccharide Intercellular Adhesin Synthesis and Autolysis

Nelson

Rice

Slater

et al. 2007

Antimicrob Agents Chemother

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The most common mechanism by which Staphylococcus aureus gains resistance to vancomycin is by adapting its physiology and metabolism to permit growth in the presence of vancomycin. Several studies have examined the adaptive changes occurring during the transition to vancomycin-intermediate resistance, leading to a model of vancomycin resistance in which decreased cell wall turnover and autolysis result in increased cell wall thickness and resistance to vancomycin. In the present study, we identified metabolic changes common to vancomycin-intermediate S. aureus (VISA) strains by assessing the metabolic and growth characteristics of two VISA strains (vancomycin MICs of 8 g/ml) and two isogenic derivative strains with vancomycin MICs of 32 g/ml. Interestingly, we observed the parental strains had impaired catabolism of nonpreferred carbon sources (i.e., acetate), and this impairment became more pronounced as vancomycin resistance increased. To determine if acetate catabolism impairment is common to VISA strains, we assessed the ability of VISA and vancomycin-sensitive S. aureus (VSSA) clinical isolates to catabolize acetate. As expected, a significantly greater percentage of VISA strains (71%) had impaired acetate catabolism relative to VSSA (8%). This is an important observation because staphylococcal acetate catabolism is implicated in growth yield and antibiotic tolerance and in regulating cell death and polysaccharide intercellular adhesin synthesis.

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Inactivated pbp4 in Highly Glycopeptide-resistant Laboratory Mutants of Staphylococcus aureus

Cited by 126 publications

References 25 publications

Molecular Characterization of an atl Null Mutant of Staphylococcus aureus

Molecular Characterization of an atl Null Mutant of Staphylococcus aureus

Reduced Vancomycin Susceptibility inStaphylococcus aureus, Including Vancomycin-Intermediate and Heterogeneous Vancomycin-Intermediate Strains: Resistance Mechanisms, Laboratory Detection, and Clinical Implications

Vancomycin-Intermediate Staphylococcus aureus Strains Have Impaired Acetate Catabolism: Implications for Polysaccharide Intercellular Adhesin Synthesis and Autolysis

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