Characteristics of staphylococci from hip prostheses infections
Abstract number: 902_p1351
Study of virulence factors of staphylococci isolated from patients with infected total hip prosthesis.
Swabs sampled from inflamed places of total hip prosthesis (THP) of patients from 1st Department of Orthopaedics were examined by standard microbiological methods in the period from January 2000 to June 2003. Antimicrobial susceptibility was tested according to NCCLS. Detection of b-lactamase was performed by nitrocefin method, and production of PBP2a was measured by latex agglutination test. Mec A gen detection was performed by PCR. Production of slime was detected by use of congo red agar plates. IcaA gen in 11 selected strains was detected by PCR. The surface hydrophobicity in all staphylococcal strains was evaluated by method based on bacterial adhesion to hydrocarbon-xylene. Haemolysins, coagulase, and DNase were tested by standard microbiological methods.
Staphylococci represented 51% of all bacterial isolates; their occurrence showed increasing tendencies during the study period. Coagulase-negative staphylococci (CoNS) prevailed (62 of 91 strains; 68%). All tested staphylococcal strains were vancomycin susceptible. 84 strains (92%) produced b-lactamase and 37 CoNS strains (60%) produced PBP2a and were mec A gen positive. Slime (a significant virulence factor in the development of endoplastitids) was produced in 10 strains (34%) of S. aureus and in 23 strains (37%) of CoNS. In 11 CoNS (a mixture of positive and negative for slime production in congo red method), icaA gen presence was tested. Only three strains were icaA positive. 12 strains (41%) of S. aureus produced a-haemolysin and two strains (7%) d-haemolysin. Delta-like toxin was produced by 24 strains (39%) of CoNS. 26 of 29 S. aureus strains produced DNase.
Staphylococci were the most frequently isolated bacteria in patients with THP infection. The occurrence of methicillin-resistant CoNS is still rather high. This fact should be taken in account in the regular updating of antimicrobial pre-, and peri-operative prophylaxis of THP patients."
|Session name:||XXIst ISTH Congress|
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