Acinetobacter nosocomialis Causes as Severe Disease as Acinetobacter baumannii in Northeast Thailand: Underestimated Role of A. nosocomialis in Infection
Arnone Nithichanon, Chidchamai Kewcharoenwong, Hudadini Da-oh, Sirithorn Surajinda, Aranya Khongmee, Surathinee Koosakunwat, Brendan W. Wren, Richard A. Stabler, Jeremy Brown, Ganjana Lertmemongkolchai
Abstract
Bacterial infections by Acinetobacter species are global threats due to their severity and high levels of antibiotic resistance. A. baumannii is the most common pathogen in the genus; however, infection by A. nosocomialis has also been widely reported but is thought to be less severe. In this study, we have prospectively investigated 48 reported cases of A. baumannii infection in Northeast Thailand, and characterized the serological responses to infection. We found that 14 (29%) of these infections were actually caused by A. nosocomialis. Furthermore, the incidence of antibiotic resistance among A. nosocomialis strains, APACHE II scores, and mortality for patients infected with A. nosocomialis were much higher than published data. Both A. baumannii and A. nosocomialis had unexpectedly mortality rates of over 30%, and both pathogens caused a high rate of community-acquired infections. Importantly, background antibodies in uninfected individuals suggest significant community exposure to both pathogens in the environment.