Abstract
Purpose: :
To identify the MLST (Mult Locus Sequences Typing) genotype of strains from Pseudomonas aeruginosa (PA) keratitis and study the relationship between genotype and antibiotic susceptibility.
Methods: :
23 strains of PA were separated from corneas of 23 keratitis patients. The genome DNA of these PA strains were extracted and amplified the 7 house-keeping genes by specific primer listed at www. pubmlst .org with PCR. The PCR products were purified and sequenced. The results were registered in MLST web. An arbitrary number was given to each distinct allele within a locus. Each isolate was therefore given seven numbers that represented its sequence type. The minimal inhibitory concentration (MIC) was performed by agar dilution method from National Committee of Clinical Laboratory Standard (NCCLS). Investigate the relationship between genotype and antibiotic susceptibility of PA strains.
Results: :
23 isolates from Beijing Tongren Hospital were resolved into 20 STs. Among these isolates, two lineages ( groupI,II) were identified. The compositions were as follows: groupI, 20 isolates (87%); groupII, 3 strains (13%). GroupIwere identified into three clonal complexes (i,ii,iii). 16 strains (about 87% ) were composed intoiiclonal complexe, which was mainly composed of A (37.5%, 6 isolates) and B clonal complexes(50%, 8 isolates). MIC test showed that strains were susceptible to aminoglycosides. The activity of quinolones and cephalosporin were higher than that of aminoglycosides. There were no significant difference on MIC among different MLST genotypes of strains ( P>0.05).
Conclusions: :
MLST can determine homology of the strains from PA keratitis by clustering results. There was no finding about relationship between genetic typing and drug resistance.
Keywords: keratitis • pseudomonas • genetics