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Case Report of Primary Lung Abscesses Due to Hypervirulent Klebsiella pneumoniae (Serotype K2, Sequence Type 375): an Emerging Isolate in Okinawa, Japan

Authors Hirai J, Sakanashi D, Momose M, Koga T, Kinjo T, Haranaga S, Motonaga E, Fujita J

Received 8 March 2020

Accepted for publication 26 May 2020

Published 10 June 2020 Volume 2020:13 Pages 1691—1695


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Professor Suresh Antony

Jun Hirai,1,2 Daisuke Sakanashi,3 Masashi Momose,1 Tomomi Koga,4 Takeshi Kinjo,2 Shusaku Haranaga,5 Eiji Motonaga,6 Jiro Fujita2

1Department of Internal Medicine, Okinawa Miyako Hospital, Okinawa 906-0012, Japan; 2Department of Infectious, Respiratory and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan; 3Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi 480-1195, Japan; 4Department of Radiology, Graduate School of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan; 5Comprehensive Health Professions Education Center, University of the Ryukyus Hospital, Okinawa 903-0215, Japan; 6Department of General Medicine, Okinawa Miyako Hospital, Okinawa 906-0012, Japan

Correspondence: Jun Hirai Email

Abstract: Hypervirulent Klebsiella pneumoniae (HV-KP) is typically associated with community-acquired liver abscess and bacteremia with metastatic infection; however, primary lung abscess (PLA) caused by HV-KP is rare, with only one such case report to date. A 69-year-old man with a history of diabetes mellitus (DM) was admitted to hospital complaining of slight bloody sputum. Chest imaging showed multiple consolidations with cavities in both lung fields. A culture of bronchoalveolar lavage fluid confirmed the presence of K. pneumoniae. Genetic analyses identified the isolate as serotype K2 and sequence type 375 (K2-ST375), and that it harbored the rmpA gene. The patient was an Asian middle-aged male with DM, all of which are risk factors for HV-KP infection. Although complicating DM and the presence of the rmpA gene are more likely to induce disseminated infection, metastatic infections were not found in this patient. The clinical and microbiological characteristics of our patient were different from those of a previous reported case, although in both cases the patient was from Asia and had DM. Therefore, DM appears to be one of the predisposing factors for HV-KP lung abscesses and physicians should pay attention to emerging HV-KP lung abscess infection, particularly in Asian countries. Previous studies have also revealed that K2-ST375 is one of the major clones causing HV-KP infection, and that it is mainly isolated from patients with liver abscess. Interestingly, including the present case, most of the infectious cases caused by K2-ST375 have been reported from Okinawa Prefecture in Japan. Therefore, the trend of the K2-ST375 strain should be carefully monitored, particularly in Okinawa, Japan. The serotype of HV-KP that causes PLA is still unknown and further study is needed to elucidate the etiology of PLA due to HV-KP and the relationship between the strain K2-ST375 and PLA.

Keywords: hypervirulent Klebsiella pneumoniae, primary lung abscess, serotype K2, sequence type 375, Okinawa, Japan

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