title: Emergence of CTX-M-15 extended-spectrum beta-lactamase-producing Klebsiella pneumoniae isolates in Bosnia and Herzegovina.
abstract: Fifty-seven nosocomial Klebsiella pneumoniae isolates producing extended-spectrum beta-lactamases (ESBLs) were collected between February 2007 and November 2007 in different wards of the Sarajevo (Bosnia-Herzegovina) reference hospital. These isolates comprise two major epidemic pulsed-field electrophoresis-defined clones plus two minor clones. In addition to the ESBL-mediated resistance, all strains uniformly showed resistance to ciprofloxacin, gentamicin and tobramycin. The beta-lactamases involved in this resistance phenotype were TEM-1, SHV-1, and CTX-M-15, as demonstrated by isoelectric focusing, PCR amplification, and sequencing. TEM-1 and CTX-M-15 beta-lactamases, as well as the aminoglycoside resistance determinants, were encoded in plasmids that could be transferred to Escherichia coli by conjugation. In three of the infected patients with the predominant clone, cefoxitin resistance development (MICs >128 mg/L) was documented. The analysis of the outer membrane proteins of the cefoxitin-susceptible and cefoxitin-resistant isolates revealed that the former expressed only one of the two major porins, OmpK36, whereas in the latter, the expression of Ompk36 was altered or abolished. This is the first report of CTX-M-15-producing K. pneumoniae in Bosnia-Herzegovina. Furthermore, we document and characterize for the first time cefoxitin resistance development in CTX-M-15-producing K. pneumoniae.
authors.affiliation: Institute of Clinical Microbiology, University of Sarajevo Clinics Centre, Sarajevo, Bosnia and Herzegovina.
authors.forename: A
authors.initials: A
authors.lastname: Dedeic-Ljubovic
authors.forename: M
authors.initials: M
authors.lastname: Hukic
authors.forename: Y
authors.initials: Y
authors.lastname: Pfeifer
authors.forename: W
authors.initials: W
authors.lastname: Witte
authors.forename: E
authors.initials: E
authors.lastname: Padilla
authors.forename: I
authors.initials: I
authors.lastname: López-Ramis
authors.forename: S
authors.initials: S
authors.lastname: Albertí
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D001426:Bacterial Proteins / Q000096:biosynthesis*; D015373:Bacterial Typing Techniques; D017522:Bosnia and Herzegovina; D016000:Cluster Analysis; D003428:Cross Infection / Q000382:microbiology*; D016172:DNA Fingerprinting; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006761:Hospitals; D006801:Humans; D007525:Isoelectric Focusing; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D010957:Plasmids; D016133:Polymerase Chain Reaction; D055815:Young Adult; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000737:chemistry / Q000145:classification / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases