Sequential outbreaks in a Spanish hospital caused by multiresistant OXA-58-producing Acinetobacter baumannii ST92

• Published in: Journal of medical microbiology Vol. 63; no. 8; pp. 1093 - 1098
• Main Authors: ALVARGONZALEZ, Jorge Julio Cabrera, HERNANDO, Ana Vindel, MARTIN, Maria Dolores Rojo, CASAS, Consuelo Miranda, IGLESIAS, Jesús Oteo, MARIN, Mari Fe Bautista, ALVAREZ, Maria Luisa Azañedo, SANCHEZ, Veronica Bautista, MARI, Jose Maria Navarro
• Format: Journal Article
• Language: English
• Published: Reading Society for General Microbiology 01.08.2014
• Subjects: Acinetobacter baumannii - classification; Acinetobacter baumannii - drug effects; Acinetobacter baumannii - genetics; Acinetobacter baumannii - metabolism; Acinetobacter Infections - genetics; Acinetobacter Infections - metabolism; Anti-Bacterial Agents - pharmacology; Bacteriology; beta-Lactamases - genetics; beta-Lactamases - metabolism; Biological and medical sciences; Disease Outbreaks - statistics & numerical data; Drug Resistance, Multiple, Bacterial; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial - physiology; Gene Expression Regulation, Enzymologic; Humans; Infectious diseases; Medical sciences; Microbiology; Miscellaneous; Spain - epidemiology; Time Factors; Spain; Bacteria; Micrococcales; Acinetobacter baumannii; Multiple resistance; Neisseriaceae
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/jmm.0.067280-0

The aim of this study was to assess the epidemiology and molecular basis of the infection and dissemination of multidrug-resistant Acinetobacter baumannii (MDRAB) in three sequential outbreaks at the intensive care units (ICUs) of a tertiary university hospital in Granada, Spain, between 2009 and 2011. Strains from all patients infected and/or colonized by MDRAB during outbreak periods were characterized using PFGE and multilocus sequence typing (MLST). The first outbreak appeared in the summer of 2009 involving 38 ICU patients: 25 from a Traumatology-Rehabilitation hospital (TRH) and 13 from a Medical-Surgery hospital (MSH). Between 2010 and 2011, outbreaks were limited to the MSH-ICU, affecting 9 and 11 patients, respectively. Two PFGE types were detected. In the 2009 outbreak, two clones were identified: profile 1 strains were isolated at the TRH, whilst profile 2 was isolated at the MSH. Only one clone was identified in the 2010 and 2011 outbreaks: the profile 2 clone detected at the MSH in 2009. After MLST analysis, a single sequence type (ST92) was identified. This suggested that an endemic strain could evolve and cause localized outbreaks in vulnerable patients. Multiplex PCR for OXA group enzymes yielded a positive result for blaOXA-58-like and blaOXA-51-like genes, and gene sequencing showed the presence of blaOXA-58. However, the absence of ISAba1 upstream of the blaOXA-51-like gene suggested the absence of OXA-51 expression. The susceptibility pattern was not an appropriate method for MDRAB surveillance, as several susceptibility patterns were identified in a single clone. Consequently, molecular methods of characterization are recommended for epidemiological surveillance of MDRAB.