Epidemiology and species distribution of anaerobic Gram-negative cocci: a 10-year retrospective survey (2008-2017)

Abstract

Introduction: The group of anaerobic Gram-negative cocci (AGNC) includes the genera Veillonella, Megasphaera, Anaeroglobus, Negativicoccus and Acidaminococcus. These bacteria are an integral part of the microbiome of humans but may be causative agents in various infectious processes. The available data on the epidemiology and significance of AGNCs is scarce.
 Aims: To assess and compare the prevalence of different species of AGNCs among inpatients and outpatients at the Albert Szent-Györgyi Clinical Center retrospectively, during a 10-year study period. Methods: Isolates containing AGNC were identified retrospectively by reviewing the online microbiology records of the Institute of Clinical Microbiology.
 Results: The median age of affected patients overall was 52 years (range: 1–90 years), with a male dominance. 59.79% of samples originated from inpatients. 572 individual AGNCs isolates were recovered from clinical samples, most of the isolated GNACs were Veillonella spp. (95.28%), Megasphaera and Acidaminococcus species accounted for a minority of isolates (2.79% and 1.93%, respectively), while Anaeroglobus and Negativicoccus species were not isolated. In the second half of the study period (2013-2017), 91.31% of isolates were identified on the species level (p<0.001) using MALDI-TOF MS.
 Conclusion: The current study represents a long-term surveillance study on the isolation frequency and trends among anaerobic Gram-negative cocci (AGNCs), isolated in the Southern Great Plain of Hungary, highlighting the beneficial effect of MALDI-TOF MS on the diagnostic efficacy of the laboratories.