![]() baumannii IC2, corresponds to clonal complex 92 (CC92) according to MLST using the Oxford scheme ( Bartual et al., 2005). One of the most successful clonal lineages, A. baumannii and related species ( Gaiarsa et al., 2019). The Oxford scheme is more discriminative among closely related isolates, while the Pasteur scheme is more useful to study the population biology and epidemiological studies of A. CRAB outbreaks often show monoclonality ( Lolans et al., 2006) and multilocus sequence typing (MLST) is the reference approach for their epidemiological investigation ( Dijkshoorn et al., 1996, 2007 Zarrilli et al., 2013). CRAB outbreaks have been traced to common-source contamination and to cross-infection by the hands of healthcare workers ( Villegas and Hartstein, 2003 Maragakis et al., 2004). baumannii (CRAB) is unprecedentedly high, which, combined with clonal transmission, has led to severe clonal outbreaks with high mortality rates in ICU settings ( Siempos et al., 2010). ST369 had a high incidence density rate of CRAB bacteremia, a short time to bacteremia after ICU admission, and a high early mortality rate, which may be in part explained by its faster competitive growth rate and higher virulence than ST191.Īcinetobacter baumannii is an important cause of nosocomial infections, especially in the intensive care unit (ICU Munoz-Price et al., 2013). We report almost-complete replacement of the predominant ST191 clone by ST369 within an 8-month period at our hospital. Finally, ST369 had greater virulence and a higher mortality rate than other STs in a mouse infection model. In vitro, ST 369 isolates had significantly higher growth rates and enhanced competitive growth compared to ST191. 11 days, p = 0.01), pneumonia as an origin of bacteremia (67 vs. Compared with non-ST369, ST369 was associated with a shorter time to bacteremia from ICU admission (7 vs. ST191 predominated (61%, 27/43) from June 2016 to July 2017, whereas ST369 (72%, 98/136), which was first isolated from a patient admitted to the emergency room, replaced ST191 (15%, 21/136) after August 2017. Two dominant clones-ST369 ( n = 98) and ST191 ( n = 48)-belonging to international clone 2 (IC2) were recovered from patients admitted to intensive care units (ICUs) or wards. The predominant STs were assessed for in vitro growth, competitive growth, and virulence in a mouse model of intraperitoneal infection. One hundred and seventy-nine CRAB bloodstream isolates were collected from June 2016 to December 2019, and their MLSTs according to Oxford scheme and clinical data were obtained. By multilocus sequence typing (MLST), we evaluated the genetic relatedness of CRAB bloodstream isolates at a tertiary care hospital over a 3.5-year period and investigated the clinical and microbiologic characteristics of the predominant sequence types (STs). However, the factors related to the emergence and replacement of predominant CRAB clones in nosocomial settings are unclear. The clonal dissemination of carbapenem-resistant Acinetobacter baumannii (CRAB) bacteremia is a serious clinical problem worldwide. ![]() 2Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, South Korea.1Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea.Seong Eun Kim 1, Su-Mi Choi 1, Yohan Yu 1, Sung Un Shin 1, Tae Hoon Oh 1, Seung-Ji Kang 1, Kyung-Hwa Park 1, Jong Hee Shin 2, Uh Jin Kim 1 * † and Sook In Jung 1 * †
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