Comparison of quinolone and β-lactam resistance among Escherichia coli strains isolated from urinary tract infections

The growing frequency of antibiotic resistances is now a universal problem. Increasing resistance to new generations of β-lactam and quinolone antibiotics in multidrug- resistant Enterobacteriaceae isolates is considered an emergency health issue worldwide. The aim of this study was to evaluate plasmid-mediated quinolone resistance genes in ESBL-producing Escherichia coli isolated from urinary tract infections (UTIs). In our study ESBL- producing isolates were assessed by screening methods. After determination of antimicrobial susceptibility, detection of ESBLs and quinolone resistance genes was performed. A total of 97 ESBL-producing E. coli were determined. The blaTEM, blaSHV and blaCTX-M genes were detected in 90 isolates. The blaTEM was the most frequent- ly detected gene (46.4), followed by blaSHV (31.9) and blaCTX-M (14.4). The most prevalent quinolone resistance gene among ESBL-producing isolates was oqxAB which found in 67 isolates (69.1). The frequencies of the aac(6�)-Ib-cr, qnr and qepA were 65 (67), 8 (8.2) and 6 (6.2), respectively. Our data indicate that the prevalence of plasmid-mediated quinolone resistance genes in ESBL-positive isolates is increasing. The co-dissemination of PMQR and ESBL genes among E. coli isolates can be considered a threat to public health. Therefore, prescription of antibiotics against infectious disease should be managed carefully. © 2016, International Society of Musculoskeletal and Neuronal Interactions. All rights reserved

Relation between resistance to antipseudomonal β-Lactams and ampC and mexC genes of pseudomonas aeruginosa

Background: In order to select a better antibiotic choice for treatment of Pseudomonas aeruginosa infections, this study was conducted to determine the frequency of resistance to some antipseudomonal β-lactams in P. aeruginosa isolates from patients in Tehran, Iran. In addition, the relation between presence of genes known to be responsible for resistance to β-lactams (ampC, mexC1,2, and mexC3,4 genes) and resistance phenotype among P. aeroginosa isolates was evaluated. Methods: P. aeruginosa strains were isolated and identified by routine methods and PCR for oprL gene. Disk diffusion method was employed to determine the antimicrobial susceptibility pattern according to CLSI recommendations. PCR was used to detect the resistance genes. Results: Among 100 isolates of P. aeruginosa, 82 had ampC, 86 mexC1,2 and 89 mexC3,4 genes and combinations of these genes were seen in most of isolates and only 3 of isolates had none of these genes. Resistance to mezlocillin, cefepime, ceftazidime and piperacillin/ tazobactam was seen in 46, 41, 36 and 29 of isolates, respectively. Significant relation (P value �0.05 by Chi-square or Fisher Exact test) was observed between the presence of ampC gene and resistance to all the studied β-lactams in this study. No relation was observed for mexC genes, although many of isolates containing these two genes were phenotypically resistant. Discussion: This study had shown for the first time, the presence of ampC and mexC genes in significant percent of clinical isolates of P. aeruginosa in Tehran, Iran, and relation between presence of ampC gene and resistance to β-lactams. © 2016, Iran J Pathol. All rights reserved

VIRULENCE FACTORS, ANTIMICROBIAL SUSCEPTIBILITY AND MOLECULAR CHARACTERIZATION OF STREPTOCOCCUS AGALACTIAE ISOLATED FROM PREGNANT WOMEN

Forty-one Streptococcus agalactiae isolates collected from pregnant women at 35-37 weeks of gestation were analysed for their capsular types, antimicrobial resistance determinants, distribution of virulence factors and genetic relatedness using PCR and multiplex PCR. Capsular type III was predominant (65.8), followed by capsular type II (14.6), Ib (7.3), and V(4.9). All isolates were susceptible to penicillin, vancomycin, linezolid and quinupristin-dalfopristin. Resistance to tetracycline, erythromycin and clindamycin were found in 97.6, 24.4, and 14.6 of isolates, respectively. The most common antimicrobial resistance gene was tetM found in 97.6 of the isolates followed by ermTR and ermB found in 12 and 7.3 of isolates, respectively. The most common virulence gene was hly (100), followed by scpB (97.6), bca (97.6), rib (53.65) and bac (4.9). The insertion sequence IS1548 was found in 63.4 of isolates. By multi locus variable number of tandem repeat analysis (MLVA) typing, 30 different allelic profiles or MLVA types (MTs) were identified. The most frequent was the MT1 (5/41, 12.2) and followed by MT2 (4/41, 9.75). Our data revealed that population structure of these isolates is highly diverse and indicates different MLVA types

Comparison of quinolone and β-lactam resistance among Escherichia coli strains isolated from urinary tract infections

The growing frequency of antibiotic resistances is now a universal problem. Increasing resistance to new generations of β-lactam and quinolone antibiotics in multidrug- resistant Enterobacteriaceae isolates is considered an emergency health issue worldwide. The aim of this study was to evaluate plasmid-mediated quinolone resistance genes in ESBL-producing Escherichia coli isolated from urinary tract infections (UTIs). In our study ESBL- producing isolates were assessed by screening methods. After determination of antimicrobial susceptibility, detection of ESBLs and quinolone resistance genes was performed. A total of 97 ESBL-producing E. coli were determined. The blaTEM, blaSHV and blaCTX-M genes were detected in 90 isolates. The blaTEM was the most frequent- ly detected gene (46.4), followed by blaSHV (31.9) and blaCTX-M (14.4). The most prevalent quinolone resistance gene among ESBL-producing isolates was oqxAB which found in 67 isolates (69.1). The frequencies of the aac(6’)-Ib-cr, qnr and qepA were 65 (67), 8 (8.2) and 6 (6.2), respectively. Our data indicate that the prevalence of plasmid-mediated quinolone resistance genes in ESBL-positive isolates is increasing. The co-dissemination of PMQR and ESBL genes among E. coli isolates can be considered a threat to public health. Therefore, prescription of antibiotics against infectious disease should be managed carefully. © 2016, International Society of Musculoskeletal and Neuronal Interactions. All rights reserved