title: Prevalence of extended spectrum beta-lactamases among Enterobacteriaceae: an Italian survey.
abstract: The prevalence of extended-spectrum beta-lactamase (ESBL) production by consecutive non-repeated isolates of Enterobacteriaceae was determined over a 6-month period. A total of 8015 strains were isolated from ten Italian laboratories and 509 (6.3%) of these were designated ESBL producers from the results of a double-disk synergy test. Escherichia coli was the most isolated microrganism, followed by Klebsiella pneumoniae and Proteus mirabilis. Providencia stuartii (28.1%) was the most frequently isolated ESBL producer, followed by K. pneumoniae and Enterobacter aerogenes (20.5%). However, amongst all ESBL producers, K. pneumoniae (38.2%) was the most represented followed by P. mirabilis (25.7%). All the strains positive to DD tests were confirmed for the carriage of TEM and SHV genes using colony-blot hybridisation (CH). A total of 447 strains (88.0%) were CH-positive, of which 42.3% hybridised with the TEM-type probe, 30.1% with the SHV-type probe and 15.6% with both probes. In conclusion, our findings indicate that 6.3% of all Enterobacteriaceae tested produced ESBLs, 42.3% of which were TEM-derived enzymes. More than 20% of P. stuartii, K. pneumoniae and E. aerogenes harbour these enzymes. The double-disk test seems to be a useful test to identify ESBL producing strains.
authors.affiliation: Dipartimento di Scienze Microbiologiche, Università di Catania, Via Androne 81, 95124 Catania, Italy. bonfigio@mbox.unict.it
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bonfiglio
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: Perilli
authors.forename: Stefania
authors.initials: S
authors.lastname: Stefani
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Amicosante
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Nicoletti
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D007558:Italy; D008826:Microbial Sensitivity Tests; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000378:metabolism*; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases