Italian metallo-beta-lactamases: a national problem? Report from the SENTRY Antimicrobial Surveillance Programme.
OBJECTIVE
As part of the SENTRY Antimicrobial Surveillance Programme, 383 non-replicative randomly collected Pseudomonas aeruginosa isolates were collected during 1999-2002. These strains originated from three geographically distinct hospitals within Italy: Genoa (Northern Italy); Rome and Catania (Sicily), and were further studied to identify the prevalence of metallo-beta-lactamase (MbetaL) alleles across Italy and to determine their genetic details.


METHODS
Multidrug-resistant (MDR) strains were identified by MIC analysis followed by genotyping and PCR-based strategies.


RESULTS
Initial MIC analysis identified 31 MDR isolates that displayed an Etest MbetaL-positive phenotype. Of these, 25 produced either the MbetaL VIM-1 or IMP-13 as detected by PCR and sequencing. VIM-1-producing isolates were found at all sites, whereas IMP-13-producing isolates were only found in Rome. MbetaL-producing isolates were found at all Italian SENTRY sites and together amounted to 6.5% of all P. aeruginosa isolates. Genetic analysis indicated that many strains contained multiple integrons and identified two novel MbetaL integrons, one from the site in Genoa and one from Sicily. Integrons identical in structure and sequence to In70, the first identified and characterized bla(VIM)-containing integron from Verona, were found in isolates with distinct ribotypes at the Roman and Sicilian sites indicating that this integron has recently disseminated across Italy. All 25 MbetaL-producing isolates were genetically linked in that all isolates contained Tn5051 sequences and all harboured the insertion sequence IsPa7 which may be involved in the mobilization of these resistance alleles.


CONCLUSIONS
Taken together, these results indicate that Italy has a nationwide problem of MDR P. aeruginosa produced by mobile MbetaL genes.
Toleman
Mark A
MA
Department of Pathology & Microbiology, University of Bristol, Bristol, UK; The JONES Group/JMI Laboratories, North Liberty, IA, USA. mark.toleman@bristol.ac.uk
Biedenbach
Doug
D
Bennett
David M C
DM
Jones
Ronald N
RN
Walsh
Timothy R
TR
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015780:Carbapenems / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005838:Genotype; D006801:Humans; D032023:Integrons; D007558:Italy; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D018571:Sentinel Surveillance; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; C417264:VIM-1 metallo-beta-lactamase; C573532:IMP-13 beta-lactamase, Pseudomonas aeruginosa; D001618:beta-Lactamases