Gram-positive anaerobic cocci – commensals and opportunistic pathogens

Abstract

Among the Gram-positive anaerobic bacteria associated with clinical infections, the Gram-positive anaerobic cocci (GPAC) are the most prominent and account for approximately 25-30% of all isolated anaerobic bacteria from clinical specimens. Still, routine culture and identification of these slowly growing anaerobes to the species level has been limited in the diagnostic laboratory, mainly due to the requirement of prolonged incubation times and time-consuming phenotypic identification. In addition, GPAC are mostly isolated from polymicrobial infections with known pathogens and therefore their relevance has often been overlooked. However, through improvements in diagnostic and in particular molecular techniques, the isolation and identification of individual genera and species of GPAC associated with specific infections have been enhanced. Furthermore, the taxonomy of GPAC has undergone considerable changes over the years, mainly due to the development of molecular identification methods. Existing species have been renamed and novel species have been added, resulting in changes of the nomenclature. As the abundance and significance of GPAC in clinical infections grow, knowledge of virulence factors and antibiotic resistance patterns of different species becomes more important. The present review describes recent advances of GPAC and what is known of the biology and pathogenic effects of Anaerococcus, Finegoldia, Parvimonas, Peptoniphilus and Peptostreptococcus, the most important GPAC genera isolated from human infections.

Anaerobic Bacteria in Clinical Specimens – Frequent, But a Neglected Lot: A Five Year Experience at a Tertiary Care Hospital

“…GPAC are frequently isolated from clinical specimens and account for 24-31% of anaerobic isolates [1]. In our study, 25.3% (n=85) isolates were found to be GPAC.…”

“…In our study, 25.3% (n=85) isolates were found to be GPAC. Peptostreptococcus, Finegoldia, Parvimonas, Anaerococcus and Peptoniphilus are the more commonly reported GPAC [1]. Zone of inhibition of ≥15 mm around a 5 µg metronidazole disc differentiates GPAC from microaerophilic Gram-positive cocci.…”

“…Infections involving GPAC are usually polymicrobial and are isolated mainly from abscesses, infections of oral cavity, skin and soft tissues, bone and joints, upper respiratory and female genital tract [46]. However, F. magna is reported to be isolated as monomicrobial flora from various infection sites [1,46]. F. magna is found in high frequency in chronic wounds like diabetic ulcers and pressure ulcers [1].…”

“…Anaerobic bacteria constitute a significant proportion of the normal microbiota colonizing skin and various mucosal surfaces of human body [1]. Anaerobes are more commonly found in polymicrobial aerobic and anaerobic infections of endogenous origin.…”

Growth behavior of eikenella corrodens and streptococcus gordonii in response to a short chain fatty acid metabolite-acetic acid

“…Furthermore, E. corrodens mono-infection in germ-free rats resulted in periodontal disease with severe alveolar bone loss, indicating its role as aperiodontopathogenic bacteria (9). Streptococcus gordonii is a gram-positive, stationary, facultative anaerobe bacteria which is also one of commensal species of the human oral flora (10). S. gordonii; plays a central role in biofilm maturation by initiating biofilm formation and providing binding sites for subsequent colonizers such as Porphyromonas gingivalis (11).…”