Imported and Intensive Care Unit-BornAcinetobacter baumanniiClonal Complexes: One-Year Prospective Cohort Study in Intensive Care Patients

Abstract

The main objective of this study was to assess the frequency and possible sources of colonization and infection by Acinetobacter in the intensive care unit (ICU) of a university hospital in Rio de Janeiro, Brazil, and characterize the isolates for relatedness to internationally and locally disseminated lineages. Patients consecutively admitted to the ICU from April 2007 to April 2008 were screened for colonization and infection. Species were identified by rpoB sequencing. The presence of acquired and intrinsic carbapenemase genes was assessed by polymerase chain reaction (PCR). Strains were typed by random amplification of polymorphic DNA (RAPD)-PCR, pulsed-field gel electrophoresis, and multilocus sequence typing (MLST) using the schemes hosted at the University of Oxford (UO) and Institut Pasteur (IP). Of 234 patients, 98 (42%) had at least one specimen positive for the Acinetobacter isolate, and 24 (10%) had infection. A total of 22 (92%) infections were caused by Acinetobacter baumannii and one each (4%) by Acinetobacter nosocomialis and Acinetobacter berezinae. A. baumannii isolates from 60 patients belonged to RAPD types that corresponded to MLST clonal complexes (CCs) 109/1 (UO/IP scheme, known as International Clone I), CC 110/110 (UO/IP), CC 113/79 (UO/IP), and CC 104/15 (UO/IP). Most CCs were carbapenem resistant and carried the bla(OXA-23)-like gene. Strains were introduced by patients transferred from other wards of the same hospital (11 patients, 18%) or acquired from cross-transmission within the ICU (49 patients, 82%). A. nosocomialis lineage sequence type 260 colonized 10% of the whole study population. A. baumannii have become established in this hospital as a part of a global epidemic of successful clones. Once introduced into the hospital, such clones have become entrenched among patients in the ICU.

Association of Class 1 and 2 Integrons with Multidrug-Resistant Acinetobacter baumannii International Clones and Acinetobacter nosocomialis Isolates

“…In the present study, a similar distribution of class 1 and 2 integrons was observed in A. nosocomialis, including in CC260/71 isolates. A class 1 integron containing a metallo-␤-lactamase cassette was described in this clone from Japan and Korea (20,21); however, we did not find such genes in A. nosocomialis (10).…”

“…Four A. baumannii and one A. nosocomialis IC characterized by multilocus sequence typing (MLST) have been described and are spread in Rio de Janeiro, Brazil (9,10). The purpose of the present study was to explore the association of class 2 integrons and gene cassettes with these clonal lineages.…”

“…Between 2007 and 2008, 163 A. baumannii and 72 A. nosocomialis hospital isolates were investigated (10); 153 (94%) of the A. baumannii and 21 (29%) of the A. nosocomialis isolates were MDR. Among the A. nosocomialis isolates, antimicrobial resistance was highest for trimethoprimsulfamethoxazole (66%), cefepime (23%), and ciprofloxacin (23%) (10).…”

“…All isolates had been typed by randomly amplified polymorphic DNA (RAPD) PCR (10), and a few were typed by MLST (using University of Oxford [UO] and Institut Pasteur [IP] schemes) (9,10). In the present study, MLST was performed for all A. baumannii isolates.…”

Dissemination of Acinetobacter nosocomialis Clone among Critically Ill Patients and the Environment

“…nosocomialis typing by MLST with the UO scheme showed that one isolate obtained from lettuce belonged to ST260 (UO) and that another obtained from an ICU cabinet was a double-locus variant (DLV) of this ST. For one isolate obtained from ventilator equipment, it was not possible to amplify the gdhB gene fragment by PCR, and a complete ST profile was not determined. These results together with data from four A. nosocomialis clinical isolates from the previous study (9) are shown in Table 1. The four clinical isolates belong to RAPD [random(ly) amplified polymorphic DNA] genotype A and were obtained from three patients.…”