Molecular epidemiology of Acinetobacter baumannii spread in an adult intensive care unit under an endemic setting.

Background: Acinetobacter baumannii (Ab) clones I, III, and IV were recovered in several Buenos Aires City hospitals. We investigated the prevalence of these clones with epidemic behavior (EB) in our intensive care unit (ICU) under an endemic setting and its spread.

Methods: A 10-week prospective cohort study including surveillance cultures of newly admitted patients was conducted.

Class 1 integrons increase trimethoprim-sulfamethoxazole MICs against epidemiologically unrelated Stenotrophomonas maltophilia isolates.

Twenty-five plasmid-specified antimicrobial resistance determinants common to gram-negative bacilli from nosocomial infection were investigated from 31 Stenotrophomonas maltophilia isolates. Twenty-four clones were identified by pulsed-field gel electrophoresis, and in three clones that exhibited an increased trimethoprim-sulfamethoxazole MIC, the sul1 determinant was found. These results support not only the higher spread of class 1 integrons compared to other mechanisms but also the potential limitation of using trimethoprim-sulfamethoxazole for therapy of severe S.

Identification of an epidemic carbapenem-resistant Acinetobacter baumannii strain at hospitals in Buenos Aires City.

To identify epidemic Acinetobacter baumannii (AB) clones, 38 carbapenem-resistant AB isolates from 5 hospitals were analyzed. Macrorestriction classified 24 isolates as clone IV, susceptibility pattern clustering analysis grouped almost all of them together, and they were uniformly biotype 8. Clone IV was present at all 5 hospitals, so that it represents a carbapenem-resistant AB strain with epidemic behavior.