Temporal evolution of carbapenem-resistant Acinetobacter baumannii in Curitiba, southern Brazil.
BACKGROUND
In the last few years, carbapenem-resistant Acinetobacter baumannii isolates (CR-AB) have been identified worldwide. The first description of OXA-23-producing A baumannii in Brazil was from the city of Curitiba in 2003. The aim of the present study was to evaluate the persistence and dissemination of the first OXA-23-producing A baumannii clone isolated from patients in Hospital de Clinicas, Curitiba, Brazil.


METHODS
An antimicrobial susceptibility profile of the isolates was determined by the standard agar dilution method. Molecular detection of beta-lactamase genes was done by polymerase chain reaction. The clonal relationship of the isolates was analyzed by pulsed-field gel electrophoresis (PFGE). Epidemiologic and clinical features were evaluated as well.


RESULTS
Genotypic analysis of 172 CR-AB isolates by PFGE identified 3 distinct major PFGE clusters (A, B, and C, accounting for 36, 69, and 65 isolates, respectively). All isolates carried the bla(OXA-23)-like gene and were multidrug-resistant, but were susceptible to tigecycline and polymixin B. The mortality rate related to CR-AB infection was 45.4%, and ventilator-associated pneumonia and bloodstream infections were the most frequent clinical manifestations.


CONCLUSIONS
The presence of 3 clones among the CR-AB isolates suggests that cross-transmission was the main mechanism responsible for dissemination of OXA-23 producers. PFGE pattern A was genotypically similar to that of the first OXA-23-producing A baumannii clone identified in Curitiba in 1999. This clone persisted in the same hospital until April 2004. The presence of the bla(OXA-)23-like gene was the main mechanism associated with carbapenem resistance among the isolates studied.
Schimith Bier
Karina Eugênia
KE
Clinical Hospital, Federal University of Paraná, Curitiba, Brazil.
Luiz
Simone Oliveira
SO
Scheffer
Mara Cristina
MC
Gales
Ana Cristina
AC
Paganini
Maria Cristina
MC
Nascimento
Agnaldo José do
AJ
Carignano
Evelyn
E
Dalla Costa
Libera Maria
LM
D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D001938:Brazil / Q000453:epidemiology; D015780:Carbapenems / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D022761:Gene Transfer, Horizontal; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D016133:Polymerase Chain Reaction; D055815:Young Adult; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D001618:beta-Lactamases