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.

Microbiological and Clinical Aspects of Cervicofacial Actinomyces Infections: An Overview

“…Members of this group (including Actinomyces spp.) are considered to be low-grade pathogens, without possessing ‘classical’ virulence factors, such as exotoxins [13,14,18,53,54]. Consequently, these microorganisms can only cause disease if the normal mucosal barriers have been disrupted by exogenous or iatrogenic damage (e.g., surgical intervention, trauma, foreign bodies, concomitant infections), which explains why the mentioned predisposing factors are necessary for these infections to occur [14,18,53,54].…”

“…Similarly to other non-spore-forming Gram-positive anaerobes, members of the Actinomyces genus are important saprophytic constituents of the normal microbiota of animals and humans [2,12,13]. These microorganisms are predominantly found in the human oropharynx, and they are abundantly present in gingival crevices, periodontal pockets, tonsillar crypts, as well as on carious teeth and in dental plaques [1,5,8,11,14].…”

“…Among the results of the National Institutes of Health (NIH) Human Microbiome Project (HMP), other species, such as A. georgiae , A. gerencseriae , A. israelii , A. meyeri , A. naeslundii , A. odontolyticus , A. oricola , and A. radicidentis , were also found in the resident flora of the human oral cavity [15]. In addition, Actinomyces species colonize the upper respiratory tract, gastrointestinal tract and female genital tract [2,12,13,16]. In contrast, these microorganisms are not normally present on the surface of the skin, which is dominated by Cutibacterium (previously Propionibacterium ) spp.…”

Extraintestinal Clostridioides difficile Infections: Epidemiology in a University Hospital in Hungary and Review of the Literature

“…During the identification of the isolates, Gram-staining and growth requirements for each individual colony type (identified phenotypically using a colony microscopy) provided the basis for choosing the relevant biochemical identification tests to be used. The identification of bacterial and fungal isolates was carried out using classical biochemical tests and ATB/VITEK (bioMérieux, Marcy-l'Étoile, France) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (instrument: Microflex MALDI-TOF MS Biotyper (Bruker Daltonics Gmbh., Bremen, Germany) software: MALDI Biotyper Library 3.1); the sample-preparation methods and the technical details of the measurements were performed as previously described [52].…”

Diagnosis and Management of Cervicofacial Actinomycosis: Lessons from Two Distinct Clinical Cases

“…Identification was performed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS; Microflex MALDI Biotyper (Bruker Daltonics, Bremen, Germany)). Antimicrobial susceptibility testing (AST) was performed using E-tests on anaerobic blood agar plates, the interpretation of the results was based on EUCAST breakpoints (http://www.eucast.org/clinical_breakpoints/), taking into account the intrinsic resistance of relevant isolates [15][16][17]. The results of the AST are presented in Table 1.…”