Investigation of the prevalence of Tn<i>916</i>/Tn<i>916</i>-like elements in oral streptococci

Lunde, Tracy Munthali

doi:10.1080/20002297.2017.1325273

Cited by 2 publications

(1 citation statement)

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“…Many of the phenotype-conferring genes, such as ARGs, are located on broad-host-range mobile genetic elements (MGEs), such as conjugative plasmids or conjugative transposons (Lunde 2017). Tn916-like conjugative transposons are commonly found in over 36 different genera of bacteria and have been shown to encode tetracycline resistance conferred by tet(M) in the oral cavity (Lunde 2017). It has been shown that the presence of DNA from nonoral bacteria in the oral cavity can be transferred to oral commensals in a mixed-species oral biofilm (Roberts and Kreth 2014).…”

Section: Conjugationmentioning

confidence: 99%

Drug Resistance and Gene Transfer Mechanisms in Respiratory/Oral Bacteria

et al. 2018

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Growing evidence suggests the existence of new antibiotic resistance mechanisms. Recent studies have revealed that quorum-quenching enzymes, such as MacQ, are involved in both antibiotic resistance and cell-cell communication. Furthermore, some small bacterial regulatory RNAs, classified into RNA attenuators and small RNAs, modulate the expression of resistance genes. For example, small RNA sprX, can shape bacterial resistance to glycopeptide antibiotics via specific downregulation of protein SpoVG. Moreover, some bacterial lipocalins capture antibiotics in the extracellular space, contributing to severe multidrug resistance. But this defense mechanism may be influenced by Agr-regulated toxins and liposoluble vitamins. Outer membrane porin proteins and efflux pumps can influence intracellular concentrations of antibiotics. Alterations in target enzymes or antibiotics prevent binding to targets, which act to confer high levels of resistance in respiratory/oral bacteria. As described recently, horizontal gene transfer, including conjugation, transduction and transformation, is common in respiratory/oral microflora. Many conjugative transposons and plasmids discovered to date encode antibiotic resistance proteins and can be transferred from donor bacteria to transient recipient bacteria. New classes of mobile genetic elements are also being identified. For example, nucleic acids that circulate in the bloodstream (circulating nucleic acids) can integrate into the host cell genome by up-regulation of DNA damage and repair pathways. With multidrug resistant bacteria on the rise, new drugs have been developed to combate bacterial antibiotic resistance, such as innate defense regulators, reactive oxygen species and microbial volatile compounds. This review summaries various aspects and mechanisms of antibiotic resistance in the respiratory/oral microbiota. A better understanding of these mechanisms will facilitate minimization of the emergence of antibiotic resistance.

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Section: Conjugationmentioning

confidence: 99%