A phenotypic and genotypic investigation of Mycoplasma felis

SF600 Veterinary Medicine

McLellan, Heather ; Graham, E.

University:University of Glasgow

关键词: Mycoplasma, antimicrobial resistance, genotype, phenotype, whole genome.;   

Others  :  http://theses.gla.ac.uk/8013/1/2016McLellanMSc.pdf

来源: University of Glasgow

【 摘 要 】

Mycoplasma felis is frequently isolated from cats showing signs of respiratory orocular infection however its role as a pathogen is still undefined. Some evidencesuggests that M. felis may be a pathogen in ocular infections however evidencefor pathogenic involvement of respiratory isolates is far less definitive. Ocularclinical isolates were cultured to identify phenotype; antimicrobial susceptibilityand haemolytic activity. The strains were then sequenced along with areference strain using Next Generation Sequencing technology, to determine ifphenotype could be correlated with genotype and identify any genetic potentialfor virulence.Six antimicrobials were tested to identify antimicrobial resistance on a range ofisolates and the reference strain NCTC 10160. Fluoroquinolones were the mosteffective; however, recommendations state these should be employedconservatively as a third line antimicrobial, due to their importance in humanmedicine. Tetracyclines, the first line of treatment in M. felis infection, werealso effective with MIC90s of 0.06 μg/mL and 1 μg/mL for doxycycline andoxytetracycline, respectively. Little variance was observed between isolates,with only macrolides showing decreased efficacy. The reference isolate NCTC10160 (from 1967) demonstrated the same susceptibility as the clinical isolates(2008-2014) and so this was not considered to be novel or emerging resistance.Haemolytic activity was observed in all isolates.The clinical isolates were sequenced using Next Generation Sequencingtechnology to establish if the observed phenotype correlated with a specificgenotype. No antimicrobial resistance markers were identified. Upon alignmentwith a reference genome (M. cynos C142) several genes shared sequencehomology with good coverage, including those involved in nutrient uptake andlipoprotein signalling; however, no definitive markers of virulence wereidentified.The generated MIC data will be useful as currently there are no establishedbreakpoints in animal mycoplasmas. The MIC data available is limited andpreviously has been generated from research projects such as this. Overall, the3pathogen status of M. felis is still unclear. No antimicrobial resistance markersor known virulence markers were identified in this study, although the genesused for alignments were not exhaustive and the highly mutable genome ofmycoplasmas may mean divergent or novel resistance genes are present.