Extended-spectrum β-lactamase-producing Enterobacteriaceae: in vitro susceptibility to fosfomycin, nitrofurantoin and tigecycline.
OBJECTIVE
To assess the susceptibility trends of community-acquired extended-spectrum β-Iactamase (ESBL)-producing urinary isolates with particular reference to fosfomycin, nitrofurantoin and tigecycline.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
AlQassimi Hospital Laboratory Sharjah, Ministry of Health, Sharjah, United Arab Emirates.
M
M
Al-Zarouni
A
A
Senok
N
N
Al-Zarooni
F
F
Al-Nassay
D
D
Panigrahi
D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D000892:Anti-Infective Agents, Urinary / Q000627:therapeutic use*; D016009:Chi-Square Distribution; D004755:Enterobacteriaceae / Q000187:drug effects*; D004756:Enterobacteriaceae Infections / Q000188:drug therapy* / Q000235:genetics; D005578:Fosfomycin / Q000494:pharmacology / Q000627:therapeutic use; D005838:Genotype; D006801:Humans; D008911:Minocycline / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D009582:Nitrofurantoin / Q000494:pharmacology / Q000627:therapeutic use; D000078304:Tigecycline; D014479:United Arab Emirates; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000235:genetics / Q000382:microbiology*; D018440:beta-Lactam Resistance
D000900:Anti-Bacterial Agents; D000892:Anti-Infective Agents, Urinary; D005578:Fosfomycin; D000078304:Tigecycline; D009582:Nitrofurantoin; D008911:Minocycline