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Objectives: Temocillin is a semi-synthetic 6-α-methoxy derivative of ticarcillin. It is highly stable to most bacterial β-lactamases. However, data concerning its activity against extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae are limited. We have analysed the in vitro activity of temocillin against clinical isolates of ESBL-producing Escherichia coli over the past 4 years in a university hospital in Brussels, Belgium.Methods: Strains were screened for ESBL production using the double-disc synergy test. The MIC of 12 antimicrobial agents was determined for ESBL-producing E. coli isolates (n = 162) using the agar dilution method. ESBLs were characterized by isoelectric focusing; multiplex PCR for bla genes of the SHV, TEM and CTX-M families; and DNA sequencing.Results: ESBL-producing E. coli isolates harboured CTX-M+TEM (35%), TEM alone (44%), CTX-M alone (6%), CTX-M+SHV (2%) and other ESBL combinations (10%). The proportion of temocillin-susceptible isolates was 92%, with MIC50 and MIC90 values of 8 and 32 mg/L, respectively. Co-resistance to ciprofloxacin and co-trimoxazole in ESBL-producing E. coli was frequent (39%). The proportion of isolates not susceptible to aminoglycosides was 55, 37 and 4% for tobramycin, gentamicin and amikacin, respectively. The proportion of isolates not susceptible to ceftazidime, cefotaxime, cefepime and piperacillin/tazobactam was 70, 52, 37 and 11%, respectively. No resistance to meropenem was observed. The proportion of strains exhibiting resistance to temocillin by year was stable over the study period.Conclusions: These data indicate good in vitro activity of temocillin against multiresistant ESBL-producing E. coli. Prospective clinical studies are necessary to examine temocillin's potential role in the treatment of non-complicated infections caused by ESBL-producing E. coli. [ABSTRACT FROM AUTHOR]

Objectives 16S rRNA methylase-mediated high-level resistance to aminoglycosides has been reported recently in clinical isolates of Gram-negative bacilli only from a limited number of countries. This study was conducted to investigate the occurrence of this type of resistance in clinical isolates of Enterobacteriaceae from two Belgian hospitals and the characteristics of the strains. Methods We screened for high-level gentamicin, tobramycin and amikacin resistance in clinical isolates of Enterobacteriaceae consecutively collected between 2000 and 2005 at two laboratories by PCR for the armA, rmtA and rmtB 16S rRNA methylase genes. The β-lactamase presence in the strains was also determined by phenotypic and genotypic methods. Results Overall armA genes were detected in 18 Klebsiella pneumoniae, Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae and Citrobacter amalonaticus whereas rmtB was detected in a single E. coli isolate. The rmtA gene was not found. All 16S rRNA methylase-bearing strains produced extended-spectrum β-lactamases (ESBLs), predominantly type CTX-M-3, as well as various types of β-lactamases. In the majority of the strains, the armA gene was carried by conjugative plasmids of the IncL/M incompatibility group whereas rmtB was borne by an IncFI plasmid. Conclusions This is the first report of the emergence of 16S rRNA methylases in Enterobacteriaceae in Belgium. The rapid spread of multidrug-resistant isolates producing both ESBLs and 16S rRNA methylases raises clinical concern and may become a major therapeutic threat in the future. [ABSTRACT FROM AUTHOR]