OBJECTIVES The aim of this study was to determine the roles of mutations in the gyrA and parC genes and the overexpression of efflux pump(s) as mechanisms of resistance to quinolones. Forty-five Yersinia enterocolitica O:3 clinical isolates (41 nalidixic acid-resistant, three nalidixic acid-susceptible and one nalidixic acid-resistant strain obtained in vitro) were analysed. RESULTS All the n...

OBJECTIVE To determine the presence of fluoroquinolone resistance in Typhoidal salmonellae at Rawalpindi and the role of nalidixic acid in predicting the resistance against fluoroquinolones in Microbiology Laboratory, Department of Pathology, Army Medical College, Rawalpindi. METHODS One hundred consecutive clinical isolates of Typhoidal salmonellae isolated from blood culture samples were st...

Fluoroquinolones commonly are used to treat adult Salmonella infections. Fluoroquinolone treatment has failed for persons infected with nalidixic acid-resistant Salmonella. From 1996 to 2003, state public health laboratories forwarded 12,252 non-Typhi Salmonella enterica isolates to the Centers for Disease Control and Prevention for antimicrobial susceptibility testing; 203 (1.6%) of the isolat...

Enteric fever is the major diagnosis among febrile patients in Nepal with yearly increase in nalidixic acid resistance and reduced ciprofloxacin susceptibility among Salmonella isolates. This study was carried out to evaluate the validity of nalidixic acid resistance as an indicator of reduced susceptibility of Salmonella isolates to ciprofloxacin. In this study, 999 blood specimens collected f...

OBJECTIVES The acquisition of antibiotic-resistant commensal Escherichia coli was examined in a cohort of newborn calves. METHODS Faecal samples were collected weekly from calves over a 4 month period and screened for E. coli resistant to ampicillin, apramycin and nalidixic acid at concentrations of 16, 8 and 8 mg/L, respectively. E. coli viable counts were performed on samples from a subset ...

conclusions our findings suggested a worrying increase in resistance of v. cholerae strains to commonly used antibiotics. differences in patterns of resistance between afghan and iranian patients' samples were observed, which further emphasize a need for constant observation. results a st revealed high levels of resistance to sulfamethoxazole-trimethoprim (89.6%), tetracycline (60.4%), ampicill...

We evaluated 1,010 Salmonella isolates classified as fluoroquinolone susceptible according to the National Committee for Clinical Laboratory Standards guidelines for susceptibility to nalidixic acid and three fluoroquinolones. These isolates were divided into two distinct subpopulations, with the great majority (n = 960) being fully ciprofloxacin susceptible and a minority (n = 50) exhibiting r...

Nalidixic acid resistance has been used as a selective marker for studies of pathogen-inoculated fruits and vegetables. Three nalidixic acid–sensitive outbreak strains of Escherichia coli O157:H7 were used to generate mutants resistant to nalidixic acid (Nal, 50 g/mL) by successive culturing and selection in nalidixic acid–amended broth. The resistance to ionizing radiation of the parent and Na...

In the present study, we have encountered about 100% sensitivity to Ciprofloxacin by disc diffusion method but Nalidixic acid resistance was about 89%. Interestingly, 80 out of 93 isolates of Salmonella typhi (86.02%) and 37 out of 38 isolates of Salmonella paratyphi A (97.36%) were Nalidixic acid resistant; MIC for Ciprofloxacin being more than 1 μg/ml. This implies that Nalidixic acid resista...

The aim of this study was to evaluate the value of nalidixic acid resistance as an indicator of decreased susceptibility to ciprofloxacin (MIC = 0.125 - 1 mg/L) in Salmonella isolates from humans (n = 620) in Turkey. One isolate was found to be resistant, and the remaining isolates were susceptible to ciprofloxacin with the Clinical and Laboratory Standards Institute breakpoints; however, 75 is...