engleski

SPREAD OF CTX-M-15 POSITIVE PROVIDENTIA SPP CAUSING URINARY TRACT INFECTIONS IN UNIVERSITY HOSPITAL SPLIT IN CROATIA

AIM During 200-87, six Providencia spp (five Providencia stuarti and one Providencia rettgeri) isolates with unusual resistance phenotype were collected from various hospital units and patient's specimens in University hospital Split i Croatia. The aim of the study was to analyze the mechanisms of resistance to expanded-spectrum cephalosporins. MATERIAL AND METHODS The antimicrobial susceptibility to a wide range of antibiotics was determined by broth microdilution method according to CLSI guidelines. A double-disk-synergy test was performed to detect ESBLs. The transferability of cefotaxime resistance was determined by conjugation. The presence of genes encoding ESBLs was determined by PCR using protocols and conditions as desribed previously. Genotyping of the isolates was performed by PFGE. RESULTS All strains were positive for ESBL production by DDST. All strains were uniformly resistant to amoxycillin alone and combined with clavulanate, cefazoline, cefuroxime, ceftazidime, cefotaxime, ceftriaxone, gentamicin and ciprofloxacin. P. stuarti strains transferred cefotaxime resistance to E. coli recipient strain with frequency ranging from 10-5 to 5 x10-4. Five P. stuarti strains were positive for TEM and CTX-M β-lactamases and P. rettgeri only for TEM β-lactamases. Five CTX-M producing isolates were shown to be clonally related. CONCLUSIONS Continuos surveillance in tracking CTX-M-15-producing P. stuarti in the hospitals is necessary to prevent their spread to other hospitals and community. Global spread of ESBL positive Providencia spp all over the world is of great clinical concern.

Providencia spp; CTX-M-15 beta-lactamase; resistance

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