AUTHOR=Xi Jingyuan , Jia Peiyao , Zhu Ying , Yu Wei , Zhang Jingjia , Gao Haotian , Kang Wei , Zhang Ge , Li Jin , Wang Tong , Xu Yingchun , Yang Qiwen 

TITLE=Antimicrobial susceptibility to polymyxin B and other comparators against Gram-negative bacteria isolated from bloodstream infections in China: Results from CARVIS-NET program

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1017488

DOI=10.3389/fmicb.2022.1017488

ISSN=1664-302X

ABSTRACT=<sec><title>Objective</title><p>To investigate the bacterial distribution and antimicrobial resistance profile of clinical isolates from Gram-negative bacteria bloodstream infections (GNBSI) in China.</p></sec><sec><title>Methods</title><p>The clinical bacterial strains isolated from blood culture were collected during April 2019 to December 2021 in 21 member hospitals of China Bloodstream Gram-negative Pathogens Antimicrobial Resistance and Virulence Surveillance Network (CARVIS-NET). Antibiotic susceptibility test was conducted by broth microdilution method recommended by Clinical and Laboratory Standards Institute (CLSI, United States). WHONET 2021 and SPSS 22.0 were used to analyze data.</p></sec><sec><title>Results</title><p>During the study period, 1939 Gram-negative bacteria were collected from 21 hospitals, among which 1,724 (88.9%) were <italic>Enterobacteriaceae</italic>, 207 (10.7%) were non-fermenting Gram-negative bacteria and 8 (0.4%) were others. The top five bacterial species were <italic>Escherichia coli</italic> (46.2%), <italic>Klebsiella pneumoniae</italic> (31.6%), <italic>Pseudomonas aeruginosa</italic> (4.9%), <italic>Acinetobacter baumannii</italic> (4.2%) and <italic>Enterobacter cloacae</italic> (3.0%). For <italic>K. pneumoniae</italic>, antibiotic resistance was mainly prevalent in hospital-associated bloodstream infections, while for <italic>A. baumannii</italic>, antibiotic resistance was mainly prevalent in community-associated bloodstream infections. It is worth mentioning that 94.1% of the 1939 Gram-negative isolates were susceptible to polymyxin B. The sensitivity of the strains involved in our investigation to polymyxin B is highly correlated with their sensitivity to colistin.</p></sec><sec><title>Conclusion</title><p>The surveillance results in CARVIS-NET-2021 showed that the main pathogens of GNBSI in China were <italic>Enterobacteriaceae</italic>, while <italic>E. coli</italic> was the most common pathogen. The resistance rates of <italic>K. pneumonia</italic>, <italic>P. aeruginosa</italic>, <italic>A. baumannii</italic>, and <italic>E. cloacae</italic> to multiple antibiotics kept on a high level. In many cases, polymyxin B and colistin has become the last-resort agents to combat bloodstream infections caused by multidrug-resistant (MDR) Gram-negative bacteria.</p></sec>