AUTHOR=Lu Bing , Lin Changying , Liu Haican , Zhang Xin , Tian Yi , Huang Ying , Yan Hanqiu , Qu Mei , Jia Lei , Wang Quanyi 

TITLE=Molecular Characteristics of Klebsiella pneumoniae Isolates From Outpatients in Sentinel Hospitals, Beijing, China, 2010–2019

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2020.00085

DOI=10.3389/fcimb.2020.00085

ISSN=2235-2988

ABSTRACT=<p><bold>Background:</bold><italic>Klebsiella pneumoniae</italic> is an opportunistic pathogen associated with community-acquired and nosocomial infections. Since 2010, <italic>K. pneumoniae</italic> testing has been included into an existing diarrhea-syndrome surveillance system for estimating the prevalence of <italic>K. pneumoniae</italic> in diarrhea-syndrome patients, assessing antibiotic susceptibility, and investigating molecular characteristics of <italic>K. pneumoniae</italic>.</p><p><bold>Methods:</bold><italic>Klebsiella pneumoniae</italic> strains were isolated from stool specimens from diarrhea-syndrome outpatients in Beijing, China. Isolates were tested for antibiotic susceptibility, and phylogenetic relationships were explored though whole genome sequence analysis. Multi-locus sequence type (MLST) alleles were extracted from the whole genome sequence (WGS) data. A maximum likelihood tree was generated by MEGAX. Genomes were annotated by Prokka; core genes were produced by Roary; a maximum likelihood phylogenetic tree was generated using FastTree.</p><p><bold>Results:</bold> Forty-four <italic>K. pnuemoniae</italic> strains were isolated from 2010 to July 2019; of these 37 were <italic>K. pneumoniae</italic> and seven were <italic>K. variicola</italic>. Antibiotic susceptibility testing showed that all 44 strains were sensitive to gentamicin, imipenem, amikacin, meropenem, kanamycin; 97.73% were sensitive to cefoxitin andlavo-ofloxacin; the highest antibiotic resistance rate was 79.55%, which was to ampicillin. We found three extended-spectrum beta-lactamase (ESBL) producing strains; we identified high-virulence ST types, including ST307 and ST65; and we found that ST23 has been the epidemic clone since 2010. MLST and core genome sequence analysis showed two distinct clusters of 44 <italic>K. pnuemoniae</italic>; 40 alleles were identified in core genome sequence analysis, while 36 alleles were identified in MLST typing.</p><p><bold>Conclusions:</bold> There is an urgent need for epidemiological and molecular studies to understand the dynamics of antibiotic resistance and virulence gene transmission to guide strategies for <italic>K. pneumoniae</italic> surveillance. WGS analysis provided high discrimination power and reliable and robust data useful for molecular epidemiology.</p>