Distribution and drug resistance of 432 isolated bacteria from blood culture positive specimens

Abstract

Objective To analyze the distribution and antimicrobial resistance of isolated bacteria from blood culture positive specimens in the Shanxi Provincial People’s Hospital, so as to provide reference for clinical rational use of antibiotics to control bloodstream infection. Methods From January 2017 to December 2017, the clinical blood culture samples were cultivated continuously and the isolated strains of positive culture bottles were identified and followed by the drug sensitivity tests. The test results were interpreted according to CLSI M100-S26, using WHONET 5.6 software to analyze the test data. Results In 2017, 432 strains of non-repeatable bacteria were isolated in our hospital, of which 59.2% were aerobic gram-negative bacteria, which was significantly higher than that of aerobic gram-positive bacteria (34.5%). The top five bacteria in the detection rate were Escherichia coli, Klebsiella pneumoniae, Enterococcus faecium, Staphylococcus hominis and Acinetobacter baumannii. Drug susceptibility results showed that the detection rate of methicillin-resistant staphylococcus aureus (MRSA) was 6.7%, which was significantly lower than that of the methicillin-resistant coagulase negative staphylococcus (MRCNS, 70.9%). Staphylococcus resistant to linezolid, vancomycin, teicoplanin and tigecycline was not found. The resistance rate of Enterococcus faecium to most antibiotics was remarkably higher than that of Enterococcus faecalis, and no Enterococcus was detected resistant to linezolid, vancomycin, teicoplanin or tigecycline. The isolation rates of extended-spectrum beta-lactamases(ESBLs)-producing Escherichia coli and Klebsiella pneumoniae were 54.2% and 34.0%, respectively. Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae had a low resistance rate for cefoperazone/sulbatam, piperacillin/tazobactam and amikacin, which were completely sensitive to tigecycline. No Escherichia coli resistant to carbapenems was found. The resistance rate for imipenem and meropenem of Klebsiella pneumoniae and Enterobacter cloacae was 2.1%, 4.9% and 16.7%, 7.7%, respectively. All of these antibiotics could be used as an empirical treatment for enterobacteriaceae bacterial bloodstream infections. The drug resistance rate for imipenem and meropenem of Acinetobacter baumannii was close to 70%, and the resistance rate for other antibiotics was markedly higher than that of Pseudomonas aeruginosa. Minocycline and tigecycline could be used as the first choice for treating bloodstream infection of Acinetobacter baumannii. Conclusions The distribution and drug resistance of isolated bacteria from blood culturte in individual regions are different, and that of the same area are different in various periods. Doctors need regularly review these conditions, which provide a timely and effective laboratory basis for clinical treatment of anti-bloodstream infection. Key words: Blood culture; Isolated bacteria; Bloodstream infection; Resistance rate