Identification and Antimicrobial Susceptibility of Clinically Isolated Anaerobic Bacteria: A Retrospectively Study in a Jiangxi Tertiary-Care Hospital

Anaerobic infections have been reported for many years, and there is an increasing trend in these infections worldwide, but anaerobic infections have not received sufficient attention. Rapid identification is important for the treatment of anaerobes because of their different antibiotic-resistance profiles.

This study aimed to analyze the hospital’s present condition to improve anaerobic culture detection rates and enhance the monitoring of anaerobes in hospitals.

This study retrospectively analyzed sterile body fluids sent to the First Affiliated Hospital of Nanchang University in the form of culture bottles in 2017. Finally, 28 strains of obligate anaerobes were isolated, then combined 16S rRNA gene sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to identify the strains and performed separate antimicrobial susceptibility testing.

The results showed that these two methods are highly consistent. There were 17/28 (61%) Gram-negative and 11/28 (39%) Gram-positive bacteria. The predominant bacteria were Bacteroides fragilis (15/28). Ten strains were isolated from the Obstetrics and Gynecology Department. The next most frequently affected departments were General Surgery (17.86%) and the ICU (17.86%). We analyzed the resistance to penicillin, cefoxitin, clindamycin, metronidazole, meropenem, piperacillin/tazobactam and amoxicillin/clavulanic acid by using the agar dilution method. The resistance rates to clindamycin were relatively high but relatively sensitive to metronidazole.

The results of this research indicate that we should pay attention to the cultivation of anaerobic bacteria, especially in certain high-risk departments.