title: Molecular epidemiology and antimicrobial susceptibility of extended- and broad-spectrum beta-lactamase-producing Klebsiella pneumoniae isolated in Portugal.
abstract: All 187 Klebsiella pneumoniae isolated over six consecutive months of 1999 in 17 Portuguese health institutions were studied: 89% were resistant to ampicillin, 31% to trimethoprim/sulfamethoxazole, 17% to aminoglycosides and 3% to fluoroquinolones; 16% were multidrug-resistant and 14% expressed an extended-spectrum beta-lactamase (ESBL) phenotype confirmed by genotyping. Molecular methods identified: 11 isolates possessing bla(ESBL-SHV) genes (bla(SHV-2A), bla(SHV-5), bla(SHV-12) and bla(SHV-55)), 9 isolates with bla(ESBL-TEM) (bla(TEM-3), bla(TEM-10) and bla(TEM-24)) and 7 isolates with bla(GES-1), encoding ESBL enzymes; and 160 isolates with bla(SHV-1) and bla(SHV-type) encoding non-ESBL enzymes. Overall, 15 new beta-lactamases were detected: SHV-60 to SHV-62, SHV-71 and SHV-73 to SHV-83. The genetic relatedness of 108 isolates was studied by pulsed-field gel electrophoresis (PFGE) analysis. The isolates were diverse and 18 clusters were defined, the largest including 12 isolates of different specimens, 6 of which expressed GES-1 enzymes. Twenty additional strains isolated during a second period (March-November 2006) in three of the participating hospitals contained ESBL-encoding genes, whereas none of the isolates in the same hospitals in 1999 carried such genes: bla(SHV-5), bla(SHV-12), bla(TEM-10), bla(TEM-52), bla(CTX-M-15), bla(CTX-M-32) and bla(CTX-M-61) (first described in the country). In this period, three new enzymes were detected: SHV-106 to SHV-108. We provide evidence that the genotypes of K. pneumoniae isolates is changing towards the emergence of ESBL enzymes.
authors.affiliation: Antibiotic Resistance Unit, Department of Infectious Diseases, National Institute of Health Dr Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
authors.forename: Nuno
authors.initials: N
authors.lastname: Mendonça
authors.forename: Eugénia
authors.initials: E
authors.lastname: Ferreira
authors.forename: Deolinda
authors.initials: D
authors.lastname: Louro
authors.forename: Manuela
authors.initials: M
authors.lastname: Caniça
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology* / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000145:classification* / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D011174:Portugal / Q000453:epidemiology; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001618:beta-Lactamases