A 12-year epidemiological study of Acinetobacter baumannii from blood culture isolates in a single tertiary-care hospital using polymerase chain reaction (PCR)-based open reading frame typing

Yuji Fujikura; Takaaki Hamamoto; Atsushi Yuki; Ayumi Sampei; Nozomi Ichie; Kazuho Takamizawa; Sakika Nomura; Yusuke Serizawa; Tomohiro Ohno; Hironori Tsujimoto

doi:10.1017/ash.2022.279

A 12-year epidemiological study of Acinetobacter baumannii from blood culture isolates in a single tertiary-care hospital using polymerase chain reaction (PCR)-based open reading frame typing

Antimicrob Steward Healthc Epidemiol. 2022 Aug 8;2(1):e136. doi: 10.1017/ash.2022.279. eCollection 2022.

Authors

Affiliations

¹ Department of Medical Risk Management and Infection Control, National Defense Medical College Hospital, Tokorozawa, Saitama, Japan.
² Division of Infectious Diseases and Respiratory Medicine, Department of Internal Medicine, National Defence Medical College, Tokorozawa, Saitama, Japan.
³ Department of Clinical Laboratory, National Defence Medical College Hospital, Tokorozawa, Saitama, Japan.

Abstract

Objective: Acinetobacter baumannii is a causative agent of healthcare-associated infections, and the introduction and spread of A. baumannii that has acquired drug resistance within a hospital are serious healthcare problems. We investigated the transition of epidemic clones and the occurrence of outbreaks by molecular epidemiological analysis to understand the long-term behavior of A. baumannii within a single facility.

Methods: A. baumannii isolates collected from blood-culture-positive patients between January 2009 and December 2020 were subjected to PCR-based open reading frame typing (POT) for species identification, clonal typing, and homology searches.

Results: Of the strains isolated from blood cultures, 49 were identified as A. baumannii and analyzed with POT. The POT#1=122 clones had different antimicrobial resistance profiles to the other POT clones, and strains belonging to this clone were dominant during outbreaks of multidrug-resistant Acinetobacter. Although the clonal diversity of A. baumannii decreased and its antimicrobial resistance increased during the outbreaks, clonal diversity and the in-hospital antibiogram improved at the end of the outbreaks. The POT#1=122 clone was not eliminated from the hospital during the study period.

Conclusions: POT is a simple and suitable method for molecular epidemiological monitoring and can show the introduction, outbreak, and subsequent transition of an epidemic clone of A. baumannii.