AbstractEndogenous Staphylococcus aureus sortase A (SrtA) covalently incorporates cell wall anchored proteins equipped with a SrtA recognition motif (LPXTG) via a lipid II-dependent pathway into... Show moreAbstractEndogenous Staphylococcus aureus sortase A (SrtA) covalently incorporates cell wall anchored proteins equipped with a SrtA recognition motif (LPXTG) via a lipid II-dependent pathway into the staphylococcal peptidoglycan layer. Previously, we found that the endogenous S. aureus SrtA is able to recognize and process a variety of exogenously added synthetic SrtA substrates, including K(FITC)LPMTG-amide and K(FITC)-K-vancomycin-LPMTG-amide. These synthetic substrates are covalently incorporated into the bacterial peptidoglycan (PG) of S. aureus with varying efficiencies. In this study, we examined if native and synthetic substrates are processed by SrtA via the same pathway. Therefore, the effect of the lipid II inhibiting antibiotic bacitracin on the incorporation of native and synthetic SrtA substrates was assessed. Treatment of S. aureus with bacitracin resulted in a decreased incorporation of protein A in the bacterial cell wall, whereas incorporation of exogenous synthetic substrates was increased. These results suggest that natural and exogenous synthetic substrates are processed by S. aureus via different pathways. Show less
Totte, J.E.E.; Feltz, W.T. van der; Hennekam, M.; Belkum, A. van; Zuuren, E.J. van; Pasmans, S.G.M.A. 2016
This study analysed 330 Clostridium difficile strains isolated from patients with C. difficile infection who were hospitalized in two university hospitals (H1 and H2) in Warsaw, Poland, over the... Show moreThis study analysed 330 Clostridium difficile strains isolated from patients with C. difficile infection who were hospitalized in two university hospitals (H1 and H2) in Warsaw, Poland, over the period 2004-2006. Strains were investigated for the presence of tcdA (A), tcdB (B) and binary toxin (CDT) genes, and antimicrobial susceptibility was determined against nine agents. Among the 330 C. difficile isolates, 150 (45.4%) were classified as A(+)B(+)CDT(-), 18 (5.5%) as A(+)B(+)CDT(+), 144 (43.6 %) as A(-)B(+)CDT(-) and 18 (5.5 %) as A(-)B(-)CDT(-). The predominant PCR ribotype in hospitals H1 and H2 was type 017 and accounted for 48.3 and 40.0%, respectively. Only one PCR ribotype 027 strain was found. The rates of resistance to erythromycin and clindamycin in hospitals H1 and H2 were 53.6 and 53.6%, and 48.6 and 47.5%, respectively, whereas resistance rates to the newer fluoroquinolones gatifloxacin and moxifloxacin were 38.5 and 38.5% (H1) and 38.4 and 40.1% (H2). Erythromycin resistance was frequently associated with resistance to clindamycin and newer fluoroquinolones in strains belonging to type 017. No metronidazole- and vancomycin-resistant isolates were found, although two C. difficile isolates had elevated MIC values of metronidazole (MIC range 1.0-1.5 mg l(-1)) and 15 strains revealed elevated MIC values for vancomycin (MIC range 1.5-2.0 mg l(-1)). In conclusion, an increase in non-027 CDT-producing C. difficile strains was observed in Poland, but C. difficile PCR ribotype 017 remains a major circulating type. Show less
Guerrier-Takada, C.; Belkum, A. van; Pleij, C.W.A.; Altman, S. 1988
