Anaerobic infections in patients admitted in various surgical units of a tertiary care hospital of north India: neglected but important

Charu Singh; Anshul Sood; Kiran Bala; Cherring Tandup; Pallab Ray; Archana Angrup

doi:10.18502/ijm.v13i3.6387

Anaerobic infections in patients admitted in various surgical units of a tertiary care hospital of north India: neglected but important

Iran J Microbiol. 2021 Jun;13(3):274-281. doi: 10.18502/ijm.v13i3.6387.

Authors

Charu Singh¹, Anshul Sood², Kiran Bala², Cherring Tandup³, Pallab Ray², Archana Angrup²

Affiliations

¹ Department of Microbiology, IMS-BHU, Varanasi, India.
² Department of Medical Microbiology, Research Block A, PGIMER, Chandigarh, India.
³ Department of General Surgery, PGIMER, Chandigarh, India.

Abstract

Background and objectives: Anaerobic infections are usually caused by the host's endogenous flora due to a breach in the anatomical barriers and Bacteroides spp. are the most notorious organisms associated with anaerobic infections. The identification of anaerobes has been a challenge since times. MALDI-TOF-MS is a boon for aiding the rapid detection of anaerobic organisms and has helped us to enlist the distribution of various anaerobic pathogens.

Materials and methods: This retrospective analysis (January 2018 to December 2019) was carried out in a tertiary care hospital in North India, in which the anaerobic microbiological profile of all patients admitted to surgical wards, ICU, and OPD of various departments (Orthopedics, Surgery, Gynecology, and Obstetrics) was reviewed. Samples received were immediately processed aerobically (5% sheep blood agar and Mac Conkeyagar) as well as anaerobically (RCM and freshly prepared sheep blood agar) as per the laboratory protocols.

Results: Bacteroides fragilis (19.12%) was the most common anaerobe whereas among aerobes Escherichia coli (30.2%) followed by Klebsiella pneumoniae (10.34%) were most commonly isolated. The majority of patients were males (56%) and the most common presentation was with abscesses (21.4%). Polymicrobial infections (69.51%) outnumbered monomicrobial ones (30.48%).

Conclusion: There is a paucity of literature on anaerobe isolation from surgical infections from our country which motivated us to study anaerobic infections and the high sample size in our institute enabled us to study surgical infections from an anaerobic perspective. This will add to the knowledge of microbiologists and clinicians. MALDI-TOF MS helped in rapid and accurate identification and hence we could report a wider spectrum of organisms in our study.

Keywords: Anaerobic bacteria; Bacteroides fragilis; Matrix assisted laser desorption/ionizationtime of flight mass spectrometry; Metronidazole; Oxidation-reduction potential; Resistance.