Microbial profile of root canals of pulpally infected teeth in Ghanaians

Introduction: Pulpal and periapical infections are initiated by microorganisms when they gain access to the dental pulp. The success of root canal treatment principally depends on the eradication of the micro-organisms in the root canal system. The aim of this study was to evaluate the viable microbial profile of root canals with various stages of infection in Ghanaians. Material and Methods: Forty-four consecutive patients with sixty teeth referred to the Restorative Dentistry Clinic requiring root canal treatment were recruited. Root canal samples were collected from the teeth with sterile paper points. The samples were processed and subjected to microbial analysis and identification using Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS). Results: A total of 259 isolates were recovered from the 60 infected root canals, belonging to twenty different microbial genera. Out of the 259 microbial species isolated, only two were Candida albicans, a fungi; 257 (99.2%) were bacterial isolates belonging to 19 genera. The 19 genera encompassed 53 bacterial species, out of which 26 (49.1%) were identified as facultative anaerobes, 15 (28.3 %.) as obligate anaerobes and 12 (22.6%) were aerobes. Streptococcus species (Streptococcus oralis, Streptococcus mitis, Streptococcus mutans and Streptococcus constellatus) were the most predominant isolates, followed by Prevotella sp, Actinomyces sp, Enterococcus faecalis and Rothia sp respectively. Conclusion: The findings of this study show that infected root canals are polymicrobial in nature. The determination of the microbial profile aids in understanding the pathogenesis of pulpal and periradicular infections and helps in choosing effective antimicrobial irrigation and medicament for root canal treatment

A molecular and epidemiological study of Vibrio cholerae isolates from cholera outbreaks in southern Ghana.

Cholera remains a major global public health threat and continuous emergence of new Vibrio cholerae strains is of major concern. We conducted a molecular epidemiological study to detect virulence markers and antimicrobial resistance patterns of V. cholerae isolates obtained from the 2012-2015 cholera outbreaks in Ghana. Archived clinical isolates obtained from the 2012, 2014 and 2015 cholera outbreaks in Ghana were revived by culture and subjected to microscopy, biochemical identification, serotyping, antibiotic susceptibility testing, molecular detection of distinct virulence factors and Multi-Locus Variable-Number of Tandem-Repeat Analysis (MLVA). Of 277 isolates analysed, 168 (60.6%) were confirmed to be V. cholerae and 109 (39.4%) isolates constituted other bacteria (Escherichia coli, Aeromonas sobria, Pseudomonas aeruginosa, Enterobacter cloacae and Enterococci faecalis). Serotyping the V. cholerae isolates identified 151 (89.9%) as Ogawa, 3 (1.8%) as Inaba and 14 (8.3%) as non-O1/O139 serogroup. The O1 serogroup isolates (154/168, 91.7%) carried the cholera toxin ctxB gene as detected by PCR. Additional virulence genes detected include zot, tcpA, ace, rtxC, toxR, rtxA, tcpP, hlyA and tagA. The most common and rare virulence factors detected among the isolates were rtxC (165 isolates) and tcpP (50 isolates) respectively. All isolates from 2014 and 2015 were multidrug resistant against the selected antibiotics. MLVA differentiated the isolates into 2 large unique clones A and B, with each predominating in a particular year. Spatial analysis showed clustering of most isolates at Ablekuma sub-district. Identification of several virulence genes among the two different genotypes of V. cholerae isolates and resistance to first- and second-line antibiotics, calls for scaleup of preventive strategies to reduce transmission, and strengthening of public health laboratories for rapid antimicrobial susceptibility testing to guide accurate treatment. Our findings support the current WHO licensed cholera vaccines which include both O1 Inaba and Ogawa serotypes