Iranshahi N, Ranjbar R, Siadat S D, Nejati M, Harzandi N, Norozian D, et al . Evaluation of nalidixic acid susceptibility testing for screening ofclinical strains of Salmonella with decreased susceptibility to ciprofloxacin. Iran J Med Microbiol 2009; 2 (3 and 4) :39-45
URL:
http://ijmm.ir/article-1-127-en.html
Negin Iranshahi1 ,
Reza Ranjbar2 ,
Seyed Davar Siadat3 ,
Mahdi Nejati3 ,
Naser Harzandi1 ,
Dariush Norozian3 ,
Ali Naghoni1 ,
Said Morovvati2 ,
Zahra Safiri2 ,
Soheila Yousefi2 ,
Bahman Tabaraie 4
1- Department of Microbiology, Islamic Azad University-Karaj Branch, Iran
2- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
3- Bacterial vaccine and antigen preparation unit, Research and Production Complex, Pasteur Institute of Iran
4- Bacterial vaccine and antigen preparation unit, Research and Production Complex, Pasteur Institute of Iran , tabaraie@kfg.ir
Abstract: (15887 Views)
Background and objectives: Fluoroquinolones, in particular ciprofloxacin have recently become the drug of
choice for antibiotic therapy of invasive Salmonella infections in many countries. however, several treatment
failures due to Salmonella strains with decreased susceptibility to ciprofloxacin have been reported. These
isolates are still considered to be susceptible to ciprofloxacin according to CLSI interpretive criteria (MIC≤1
µg/ml) while they can not be detected by disk diffusion test. CLSI has recommended nalidixic acid disk
diffusion as an indicator test for screening of Salmonella isolates with decreased susceptibility to ciprofloxacin.
In this study the value of nalidixic acid susceptibility testing for screening ofclinical strains of Salmonella with
decreased susceptibility to ciprofloxacin was evaluated.
Material and methods: Salmonella spp. strains have been isolated from several provinces in Iran during 2007-
2008. The strains were identified by standard biochemical tests and serology. The susceptibility of the isolates
to nalidixic acid and ciprofloxacin was determined by disk diffusion method. MIC assay for ciprofloxacin was
determined by E. test.
Results: 28 out of 53 Salmonella strains (52.8%) were resistant to nalidixic acid. Disk diffusion testing showed
that all isolates were susceptible to ciprofloxacin however 8 (15%) resistant nalidixic acid isolates showed
decreased susceptibility to ciprofloxacin (MIC= 0.125 µg/ml) when tested by E.test.
Conclusion:The results showed that nalidixic acid disk diffusion test can be considered as a reliable and costeffective method for screening of Salmonella strains with low level resistance to ciprofloxacin.
Type of Study:
Original Research Article |
Subject:
Molecular Epidemiology Received: 2013/11/16 | Accepted: 2013/11/16 | ePublished: 2013/11/16