engleski

Multidrug resistant Acinetobacter baumannii inside and outside hospital setting

Acinetobacter baumannii has emerged as one of the most common nosocomial pathogens worldwide. This organism mostly targets the susceptible immunocompromised patients in ICUs where natural barriers are breached by trauma, surgery or mechanical support ventilation. Mortality rates of infections 11. hrvatski kongres kliničke mikrobiologije i 8.hrvatski kongres o infektivnim bolestima Poreč, Hrvatska, 20.–23. listopada 2016. 11th Croatian Congress of Clinical Microbiology and the 8th Croatian Congress for Infectious Diseases Poreč, Croatia, October 20–23, 2016 68 caused by Acinetobacter can be more than 75% in the ICU patients with the respiratory tract being the natural and major portal of entry. While it is certainly true that A. baumannii can be isolated from patients and hospital environmental sources during outbreaks, this species has no known natural habitat outside the hospital setting. The answers to crucial questions regarding the epidemiology of A. baumannii are still not known: are the infected patients and hospital environment only sources of A. baumannii, or do clinical isolates of A. baumannii survive or even multiply in nature and have natural habitat outside hospitals. In several investigations of two collaborative centres from Split and Zagreb during 2014/15 (project IP-2014-09-5656, supported by the Croatian Science Foundation) more than twenty multidrug resistant isolates of A. baumannii from hospital and municipal wastewater were collected. Molecular identification of environmental isolates of A. baumannii was performed by amplification, sequencing, and phylogenetic analyses of rpoB gene. The presence of blaOXA genes encoding OXA-type carbapenemases (OXA-51-like, OXA-23, and OXA-40-like) was confirmed by multiplex PCR and sequencing. Obtained result suggests that isolates recovered from municipal wastewater are most probably of clinical origin. In the water environmental conditions MDR A. baumannii have the potential to multiply and survive up to 50 days. Persistence of A. baumannii harbouring the clinically important OXAs in the environmental conditions poses a potentially significant source for horizontal gene transfer and implications for wider spread of antibiotic resistance genes.

Acinetobacter baumannii; hospital; environment; multidrug-resistance

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