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1 - 2 of 2 for "F. Elizabeth Martin"
Mapping the oral resistome: a systematic review
Studying individual ecological niches within the oral cavity is a logical first step to understanding the distribution of antimicrobial resistance genes (ARGs); however it is not representative of the whole oral resistome. The aim of our systematic review was to provide a map of the oral resistome by reviewing the composition of individual niches. A total of 580 papers were retrieved from a search of all English language publications investigating the presence of oral ARGs in five electronic databases between January 2015 and August 2023. Fifteen studies [10 PCR and 5 next-generation sequencing (NGS)] were included in this review. The heterogeneity of methods precluded meta-analysis. ARGs are present throughout the oral cavity with 158 unique ARGs identified across 6 locations – supra and sub-gingival biofilm mucosa oropharynx root canal system (RCS) and saliva. The supragingival biofilm had the highest resistome richness while the RCS had the least. Tetracycline was the dominant antimicrobial resistance (AMR) class found. Three core genes were identified – tet(M) tet(O) and ermB.This review highlights the necessity of NGS studies to comprehensively characterize the oral resistome in its entirety. This is the logical foundation for future ‘omics studies to truly understand the scope of the resistome and its contribution to AMR.
Determination of bacterial load by real-time PCR using a broad-range (universal) probe and primers set
The design and evaluation of a set of universal primers and probe for the amplification of 16S rDNA from the Domain Bacteria to estimate total bacterial load by real-time PCR is reported. Broad specificity of the universal detection system was confirmed by testing DNA isolated from 34 bacterial species encompassing most of the groups of bacteria outlined in Bergey’s Manual of Determinative Bacteriology. However the nature of the chromosomal DNA used as a standard was critical. A DNA standard representing those bacteria most likely to predominate in a given habitat was important for a more accurate determination of total bacterial load due to variations in 16S rDNA copy number and the effect of generation time of the bacteria on this number since rapid growth could result in multiple replication forks and hence in effect more than one copy of portions of the chromosome. The validity of applying these caveats to estimating bacterial load was confirmed by enumerating the number of bacteria in an artificial sample mixed in vitro and in clinical carious dentine samples. Taking these parameters into account the number of anaerobic bacteria estimated by the universal probe and primers set in carious dentine was 40-fold greater than the total bacterial load detected by culture methods demonstrating the utility of real-time PCR in the analysis of this environment.