Extended-spectrum β-lactamase-producing Enterobacteriaceae: in vitro susceptibility to fosfomycin, nitrofurantoin and tigecycline.

To assess the susceptibility trends of community-acquired extended-spectrum β-Iactamase (ESBL)-producing urinary isolates with particular reference to fosfomycin, nitrofurantoin and tigecycline. Seven hospitals across the United Arab Emirates participated in this study from June 2008 to March 2010. The antibiotic sensitivity of ESBL-producing uropathogens to a panel of antibiotics including tigecycline, fosfomycin and nitrofurantoin was assessed. The Hyplex ESBL identification system (h-ES-ID) was used for genotypic identification. Two hundred and ninety-two ESBL-producing Enterobacteriaceae isolates were identified during the study period. Of these, 182 (62%) were urinary isolates and comprised of Escherichia coli: 149 (81.9%), Klebsiella pneumoniae: 30 (16.5%) and Proteus mirabilis: 3 (1.6%). Of the 182 urinary isolates, 179 (98.3%) were from patients with community onset urinary tract infections. The h-ES-ID system identified 172 (94.5%) of the urinary isolates as CTX-M positive. All isolates were susceptible to imipenem and meropenem. Over half of the isolates showed resistance to gentamicin (98; 53.8%), trimethoprim-sulfamethoxazole (139; 76.4%) and ciprofloxacin (143; 78.6%). Sensitivity to nitrofurantoin and fosfomycin was 90 and 100%, respectively. Two CTX-M-positive K. pneumoniae isolates with tigecycline resistance (MIC >4 µg/ml) were identified. There is dissemination of CTX-M ESBL-producing urinary pathogens into the community. Fosfomycin and nitrofurantoin were active against ESBL-positive uropathogens, and emergence of tigecycline resistance needs close monitoring.

Al-Zarouni M ，Senok A ，Al-Zarooni N ，Al-Nassay F ，Panigrahi D ... -  《-》

Other antimicrobials of interest in the era of extended-spectrum beta-lactamases: fosfomycin, nitrofurantoin and tigecycline.

Garau J 《CLINICAL MICROBIOLOGY AND INFECTION》

Antimicrobial susceptibilities of urinary extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae to fosfomycin and nitrofurantoin in a teaching hospital in Taiwan.

Urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae have become clinical problems because of limited therapeutic options. The role of fosfomycin in the era of growing bacteria resistance has been widely discussed recently. In this study, we aimed to know the local antimicrobial susceptibilities, fosfomycin susceptibility in particular, of urinary ESBL-producing E coli and K pneumoniae isolates in Taiwan. We collected 200 urine isolates, including 134 ESBL-producing E coli (ESBL-EC) and 66 ESBL-producing K pneumoniae (ESBL-KP) isolates from July 2008 to December 2009 in a university-affiliated teaching hospital in Taiwan. We used disk diffusion method to determine susceptibility to fosfomycin. Fosfomycin may have lower susceptibility when using disk diffusion method compared with agar dilution method. Broth microdilution test was also used to determine minimal inhibitory concentrations (MICs) and susceptibilities to other antimicrobial agents. Imipenem was active against ESBL-EC and ESBL-KP. Fosfomycin had good susceptibility to ESBL-EC (95.5%), including in hospital-acquired isolates, but lower antimicrobial activity against ESBL-KP (57.6%). Trimethoprim-sulfamethoxazole had the highest resistance rate to ESBL-EC and ESBL-KP. Comparing with non-hospital-acquired isolates, hospital-acquired ESBL-KP was associated with significantly lower susceptibility of gentamicin (13.3% vs. 66.7%), trimethoprim-sulfamethoxazole (8.9% vs. 38.1%), ciprofloxacin (26.7% vs. 61.9%), and amikacin (46.1% vs. 81.0%) (p<0.05). The resistance of some strains to ciprofloxacin was significantly associated with lower susceptibilities of gentamicin (32.6% in ESBL-EC), nitrofurantoin (2.4% in ESBL-KP) and trimethoprim-sulfamethoxazole (9.8% in ESBL-KP) (p<0.05) but not accompanied with decreasing susceptibility of fosfomycin. Fosfomycin had the excellent activity against ESBL-EC but not ESBL-KP in this study. Based on the study findings, we suggest that fosfomycin can be a therapeutic option for UTIs with ESBL-EC. Nitrofuranoin was actively against ESBL-EC. Nitrofurantoin may be an alternative option for uncomplicated UTIs with ESBL-EC in Taiwan.

Liu HY ，Lin HC ，Lin YC ，Yu SH ，Wu WH ，Lee YJ ... -  《-》

The Activity of Fosfomycin Against Extended-Spectrum Beta-Lactamase-Producing Isolates of Enterobacteriaceae Recovered from Urinary Tract Infections: A Single-Center Study Over a Period of 12 Years.

Aris P ，Boroumand MA ，Rahbar M ，Douraghi M ... -  《-》

Antibiotic coresistance in extended-spectrum-beta-lactamase-producing Enterobacteriaceae and in vitro activity of tigecycline.

Morosini MI ，García-Castillo M ，Coque TM ，Valverde A ，Novais A ，Loza E ，Baquero F ，Cantón R ... -  《-》