Outbreak of Multidrug-Resistant OXA-232-Producing ST15 Klebsiella pneumoniae in a Teaching Hospital in Wenzhou, China

Huaiyu Jia,1 Ying Zhang,2 Jianzhong Ye,1 Wenya Xu,1 Ye Xu,1 Weiliang Zeng,2 Wenli Liao,1 Tao Chen,1 Jianming Cao,2 Qing Wu,1 Tieli Zhou1 1Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People’s Republic of China; 2Department of Medical Laboratory Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People’s Republic of ChinaCorrespondence: Tieli Zhou; Qing WuDepartment of Clinical Laboratory, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of ChinaTel/Fax +86-0577-8668-9885Email wyztli@163.com; wuqing830@163.comBackground: OXA-232-producing carbapenem-resistant Klebsiella pneumoniae (CRKP) has the potential to become the “third epidemic” of carbapenem-resistant Klebsiella strain after KPC-2 and NDM in China. We investigated the first outbreak of CRKP in the First Affiliated Hospital of Wenzhou Medical University.Methods: We collected 610 clinical isolates of CRKP from the First Affiliated Hospital of Wenzhou Medical University between January 2019 and September 2020 and screened them by Polymerase Chain Reaction (PCR). The multilocus sequence typing and pulsed-field gel electrophoresis were used to determine the genetic relatedness of the strains. The antimicrobial susceptibility test was performed to determine the drug resistance of the clinical isolates. The molecular mechanism underlying carbapenem resistance was elucidated by performing PCR and conjugation experiments. The virulence potential of the strains was determined by the string test, detection of virulence-associated genes and capsular serotypes, and Galleria mellonella larval infection model.Results: Between September 2019 and May 2020, 26 OXA-232-producing CRKP were obtained from 12 patients in our hospital. Ten patients were hospitalized in the intensive care units (ICU) and the overall mortality of the inpatients involved in the outbreak was 50% (6/12). Epidemiological investigations reported that all the OXA-232-producing CRKP strains belonged to the sequence type ST15 and can be clonally transmitted among the inpatients in the ICU. All the strains had low virulence and were resistant to commonly used clinical antibiotics except for ceftazidime/avibactam, colistin, and tigecycline. The OXA-232-producing CRKP was sensitive to triclosan and chlorhexidine, and its eradication from our hospital can be achieved by the use of disinfectants in the ICU.Conclusion: In our study, OXA-232-producing CRKP isolates appeared to be clonally transmitted and the sequence type ST15 was responsible for the outbreak. Therefore, effective measurements for the infection control of CRKP are urgently needed to prevent its epidemic in the nearby region in the future.Keywords: Klebsiella pneumoniae, carbapenem-resistance, virulence, OXA-232, outbreak