title: Carbapenem-resistant Pseudomonas aeruginosa strains from a Spanish hospital: characterization of metallo-beta-lactamases, porin OprD and integrons.
abstract: Molecular typing and mechanisms of carbapenem resistance such as alterations in porin OprD and presence of metallo-beta-lactamases (MBLs), as well as integrons have been studied in a collection of carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates from a Spanish hospital. One hundred and twenty-three CRPA isolates were recovered from different samples of 80 patients. Clonal relationship among CRPA was analyzed by SpeI-PFGE. Susceptibility testing to 11 antibiotics and MBL phenotype was determined by microdilution, IP/IPI E-test and double disc method. The oprD gene was studied by PCR and sequencing, and mutations were determined comparing with P. aeruginosa PAO1 sequence. Characterization of MBLs, and class 1 and 2 integrons were studied by PCR and sequencing. SDS-PAGE analysis of outer membrane proteins of selected strains was performed. Seventy-four-per-cent of patients with CRPA were hospitalised in the ICU setting and 50% had long hospitalization stays. Sixty-four different PFGE patterns were detected, and 87 CRPA strains were further analyzed. MBL phenotype was detected in 43 of 87 strains (49.4%), which contained blaVIM-2 gene inside class 1 integrons. VIM-2-producing strains belonged to lineages ST175, ST235, and ST973. A great diversity of nucleotide insertions, deletions, and mutations in oprD gene, and the presence of a new insertion sequence (ISPa45) truncating oprD were identified among CRPA strains. Class 1 integrons were detected in 75% of CRPA strains, blaVIM-2 and the new arrangement aac(3)-Ia+ISPa34+aadA1 (named as In661) being the most frequent gene-cassette arrays detected. Other gene cassettes detected in integrons were: aadB, aadA6, aadA7, aac(6')-Ib', and blaOXA-46.
authors.affiliation: Área de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja (CIBIR), Logroño, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Rojo-Bezares
authors.affiliation: Área de Bioquímica y Biología Molecular, Departamento de Agricultura y Alimentación, Universidad de La Rioja, Logroño, Spain.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Estepa
authors.affiliation: Servicio de Microbiología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain.
authors.forename: Rocío
authors.initials: R
authors.lastname: Cebollada
authors.affiliation: Área de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja (CIBIR), Logroño, Spain; Área de Bioquímica y Biología Molecular, Departamento de Agricultura y Alimentación, Universidad de La Rioja, Logroño, Spain.
authors.forename: María
authors.initials: M
authors.lastname: de Toro
authors.affiliation: Área de Bioquímica y Biología Molecular, Departamento de Agricultura y Alimentación, Universidad de La Rioja, Logroño, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Somalo
authors.affiliation: Servicio de Microbiología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain; Departamento de Microbiología, Facultad de Medicina, Universidad de Zaragoza, Zaragoza, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Seral
authors.affiliation: Servicio de Microbiología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain; Departamento de Microbiología, Facultad de Medicina, Universidad de Zaragoza, Zaragoza, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Castillo
authors.affiliation: Área de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja (CIBIR), Logroño, Spain; Área de Bioquímica y Biología Molecular, Departamento de Agricultura y Alimentación, Universidad de La Rioja, Logroño, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Torres
authors.affiliation: Área de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja (CIBIR), Logroño, Spain. Electronic address: ysaenz@riojasalud.es.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Sáenz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015780:Carbapenems / Q000494:pharmacology*; D016521:Electrophoresis, Gel, Pulsed-Field; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006761:Hospitals; D006801:Humans; D032023:Integrons; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058889:Molecular Typing; D018272:Porins / Q000235:genetics*; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D013030:Spain; D055815:Young Adult; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D018272:Porins; C077157:OprD protein, Pseudomonas aeruginosa; D001618:beta-Lactamases
keywords: Carbapenem resistance; ISPa45; ST175; ST235; ST973; bla(VIM-2)