Detecting Gram-positive anaerobic cocci directly from the clinical samples by multiplex polymerase chain reaction in odontogenic infections

Development of multiplex PCR panel for detection of anaerobic bacteria in clinical samples

OBJECTIVE

Although anaerobic bacteria are important agents of a wide variety of serious infections, they are overlooked often in the etiology of infection due to difficulties in isolation and detection. The aim of this study was to develop a new multiplex PCR panel that could detect Bacteroides, Fusobacterium, Prevotella, Veillonella, Clostridium, Peptostreptococcus, and Actinomyces bacteria, which are the most frequently isolated from anaerobic infections, at the genus level.

METHOD

Aerobic and anaerobic cultures were performed on 46 clinical specimens, with suspicion of anaerobic infection and were sent to the laboratory. DNA isolation was performed with the same samples and anaerobic bacteria were detected by the multiplex PCR test developed in the study.

RESULT

The analytical sensitivity of the multiplex PCR assay was found to be 1-10³ CFU/ml, depending on the bacterial species. In this study, anaerobic growth was observed in eight (17.4%) of 46 clinical samples. The multiplex PCR test detected 35 anaerobic bacteria from 20 (43.5%) of 46 clinical samples. The most common anaerobes isolated from clinical specimens by the multiplex PCR assay were Prevotella spp. (37.1%) and Fusobacterium spp. (22.9%) while Clostridium spp. (14.3%), Peptostreptococcus spp. (11.4%), Bacteroides spp. (8.6%), and Veillonella spp. (5.7%) followed these genera.

CONCLUSION

As a result, it was concluded that the multiplex PCR panel developed in this study eliminates problems in the detection of anaerobes based on culture, provides more accurate detection of anaerobic bacteria from clinical specimens, takes a shorter time, and allows more accurate infection treatment.

Aerobic and anaerobic microorganisms and antibiotic sensitivity of odontogenic maxillofacial infections

This study aimed to identify the aerobic and anaerobic causal microorganisms of odontogenic infections and their antibiotic sensitivity. Purulent exudates were taken from patients with odontogenic infections by transdermal puncture, and aerobic and anaerobic microorganisms were identified using biochemical tests. Susceptibility to antibiotics was tested using the Kirby-Bauer method; the inhibition halos were measured according to NCCLS, and based on the results, the microorganisms were classified as susceptible, intermediate or resistant to each antibiotic. Frequencies of species and percentages of resistance were calculated. The microorganisms associated with odontogenic infections were principally anaerobic (65.3% anaerobic vs. 35.7% aerobic), and the susceptibility to antibiotics was higher in anaerobic than in aerobic microorganisms. The majority of isolated microorganisms (82%) showed susceptibility to amoxicillin/clavulanic acid. The causal agents of odontogenic infections were anaerobic microorganisms, which exhibited high resistance to antibiotics.

First case of infectious endocarditis caused by Parvimonas micra

P. micra is an anaerobic Gram-positive cocci, and a known commensal organism of the human oral cavity and gastrointestinal tract. Although it has been classically described in association with endodontic disease and peritonsillar infection, recent reports have highlighted the role of P. micra as the primary pathogen in the setting of invasive infections. In its most recent taxonomic classification, P. micra has never been reported causing infectious endocarditis in humans. Here, we describe a 71 year-old man who developed severe native valve endocarditis complicated by aortic valvular destruction and perivalvular abscess, requiring emergent surgical intervention. Molecular sequencing enabled identification of P. micra.