Variable susceptibility to piperacillin/tazobactam amongst Klebsiella spp. with extended-spectrum beta-lactamases.
نویسندگان
چکیده
MICs of piperacillin/tazobactam are conventionally determined by varying the concentration of piperacillin in the presence of a fixed 4 mg/L tazobactam. When tested in this way, the MIC distribution for Klebsiella isolates with extended-spectrum beta-lactamases (ESBLs) is strongly bimodal, such that many producers are inhibited at 16 + 4 mg/L whilst others require MICs of > or =512 + 4 mg/L. When, however, piperacillin/tazobactam was tested as a fixed 8:1 ratio, the MIC distribution became unimodal. If clavulanate 4 mg/L was combined with piperacillin, a unimodal MIC distribution was seen for ESBL-producing Klebsiella spp. but a bimodal distribution arose if the clavulanate concentration was reduced to 0.25 mg/L. These data for alternative combinations suggested that the bimodal MIC distribution seen for piperacillin + tazobactam 4 mg/L was a titration effect, not a reflection of some ESBLs being resistant to tazobactam. Even within single strains, as defined by serotype and DNA fingerprints, there was considerable variation in susceptibility to piperacillin + tazobactam 4 mg/L, with some representatives highly susceptible and others highly resistant. Some of the more resistant representatives produced more of their ESBL, or had a greater number of beta-lactamase types, but these associations were not universal. Elevated resistance to piperacillin + tazobactam was not associated with porin change in any ESBL producer examined, but has been found by others.
منابع مشابه
Antibiotic resistance in gram-negative bacilli: a Singapore perspective.
INTRODUCTION Antibiotic resistance in gram-negative bacilli is an area of increasing importance. This prospective study was performed to survey antibiotic resistance in Escherichia coli (E. coli), Klebsiella spp., Pseudomonas aeruginosa and Acinetobacter spp. over a 1-year period. MATERIALS AND METHODS Non-duplicate isolates of E. coli, Klebsiella spp., P. aeruginosa and Acinetobacter spp. we...
متن کاملDetermination of Prevalence and Antibacterial Activity of Esbl (extended Spectrum Beta-lactamases) Producing Klebsiella Species Isolated from Raw Milk of Doon Valley in India
Milk is a key contributor to improving nutrition and food security. The virtues of milk as a food have long been recognized by human beings. Milk is however a good medium for bacterial growth and an efficient vehicle for bacterial infection when consumed without boiling or pasteurization. The aim of the present study was to evaluvate the presence of ESBL producing Klebsiella species present in ...
متن کاملMolecular epidemiology of a citywide outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae infection.
Multidrug-resistant strains of Klebsiella pneumoniae are a problem in many hospitals. In 1999, the molecular epidemiology of K. pneumoniae with extended-spectrum beta-lactamases (ESBLs) was studied at 15 hospitals in Brooklyn. Of 824 unique patient isolates, 34% were presumptive ESBL producers. Of this subset, 34% were susceptible to cefoxitin, 42% to ciprofloxacin, 48% to ceftriaxone, 55% to p...
متن کاملPrevalence and antimicrobial susceptibility pattern of extended-spectrum beta-lactamase-producing Enterobacteriaceae in the United Arab Emirates.
OBJECTIVE To investigate the prevalence and antibiotic susceptibility pattern of extended-spectrum beta-lactamases (ESBL)-producing Enterobacteriaceae among patients in the United Arab Emirates. MATERIALS AND METHODS A total of 130 Enterobacteriaceae comprising of Escherichia coli (n = 83), Klebsiella pneumoniae (n = 45) and Klebsiella oxytoca (n = 2) was studied. Of these 130 isolates, 64 we...
متن کاملAntibiotic combination as empirical therapy for extended spectrum Beta-lactamase.
BACKGROUND extended spectrum β-lactamase (ESBL) producing gram negative bacilli are becoming a growing problem worldwide with difficulties in designing a national formulary for empirical treatment of gram negative sepsis. OBJECTIVES In this study, we investigated the in vitro activity of Carbapenems, Pipracillin-Tazobactam, Ciprofloxacin alone or in combination with aminoglycosides against ES...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The Journal of antimicrobial chemotherapy
دوره 51 3 شماره
صفحات -
تاریخ انتشار 2003