AUTHOR=Shi Ting , Xie Liangyi 

TITLE=Distribution and antimicrobial resistance analysis of gram-negative bacilli isolated from a tertiary hospital in Central China: a 10-year retrospective study from 2012 to 2021

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1297528

DOI=10.3389/fmicb.2023.1297528

ISSN=1664-302X

ABSTRACT=<sec id="sec1"><title>Background</title><p>Gram-negative bacilli are one of the most common causes of various infections in clinical. The emergence and global spread of multi-drug resistant gram-negative bacilli has become a major challenge in the global public health field.</p></sec><sec id="sec2"><title>Methods</title><p>A total of 51,189 non-repetitive strains of gram-negative bacilli were isolated in clinical settings. The antimicrobial susceptibility testing was conducted by using the automated VITEK 2 compact system and the matched AST susceptibility test card, complemented by the disk diffusion method. The antimicrobial susceptibility results were interpreted by CLSI. Rates of MDR and XDR in <italic>Klebsiella pneumoniae</italic>, <italic>Acinetobacter baumannii</italic>, and <italic>Pseudomonas aeruginosa</italic> were investigated. Used the chi-square test to determine whether the antimicrobial resistance rates of four major gram-negative bacilli isolated from ICU and non-ICU department have statistical differences.</p></sec><sec id="sec3"><title>Results</title><p><italic>Escherichia coli</italic> (31.4%), <italic>Klebsiella</italic> spp. (21.2%), <italic>Acinetobacter</italic> spp. (13.8%), and <italic>P. aeruginosa</italic> (11.0%) were the most frequently isolated gram-negative bacilli. <italic>Escherichia coli</italic> was the top one organism isolated from urinary tract (68.4%), bloodstream (39.9%), body fluid (33.2%), wound and pus (37%), except for respiratory tract (8.8%). Whereas <italic>Acinetobacter baumannii</italic> and <italic>K. pneumoniae</italic> were the major isolated organisms from respiratory tract. <italic>Acinetobacter baumannii</italic> showed high resistance to fluoroquinolones, β-lactam/β-lactamase inhibitor combinations class, ceftazidime, cefepime, imipenem, and meropenem, the resistance rates reached more than 70%. Ceftazidime showed a lower resistance rate to <italic>E. coli</italic> than ceftriaxone. For <italic>E. coli</italic>, fluoroquinolones showed a high resistance rate (ciprofloxacin 61.36% and levofloxacin 53.97%), whereas amikacin, carbapenems exhibited a lower resistance rate fluctuating at 2%. <italic>Acinetobacter baumannii</italic> and <italic>K. pneumoniae</italic> showed rapid increases in carbapenem resistance whereas <italic>E. coli</italic> had the lowest resistance rate and remain stable at 2%. <italic>Acinetobacter baumannii</italic> exhibited the highest rate of MDR and XDR, reaching 60–80 and 45–55%, respectively. Compared to non-ICU departments, the resistance rates of four major gram-negative bacilli in the ICU department were much higher and the differences were statistically significant (<italic>p</italic> &lt; 0.05).</p></sec><sec id="sec4"><title>Conclusion</title><p>Amikacin, carbapenems, and piperacillin/tazobactam exhibited relatively high sensitivity, whereas fluoroquinolones showed high resistance rate whether they can be the first-line antimicrobials for empirical treatment of UTI should take more consideration. The gram-negative bacilli in ICU were more resistance than that in non-ICU. These findings are helpful for clinicians using antimicrobials reasonably.</p></sec>