Relationship between the Susceptibility of Salmonella.Typhi to Ciprofloxacin, Ofloxacin and their respective Susceptibility To Nalidixic Acid

Abstract

Background: Typhoid fever is an important cause of morbidity and mortality in many parts of the world including Pakistan. Resistance to the first line anti typhoid drugs viz chloramphenicol, cotrimoxazole and ampicillin has aggravated this situation. Quinolones are currently used as the first line antityphoid drugs, instead. Fluoroquinolones are currently recommended for patients infected with Typhi. The fluoroquinolones have shown good in vitro as well as clinical activity against Typhi infections.Materials and Methods: It was a comparative cross-sectional conducted at Department of Microbiology UHS, Lahore, Pakistan within one year (January 2011-December 2011). A total of 100 clinical isolates of Typhi were evaluated. ATCC 9150 Paratyphi A was used as a standarad strain. The bacterial isolates were preserved in microbanks (Pro-Lab Diagnostics, UK) and stored at-70˚C during a period of (2007- 2011). Data was analysed through SPSS version 22.Results: Of the 100 isolates, 45 strains were showing MIC ≤ 1µg/ml which means that they were susceptible while 55 strains were intermediate having MIC 2µg/ml. No strain was however, found resistant to ciprofloxacin according as per the CLSI 2011. As per the CLSI 2012 revised ciprofloxacin break points for disc diffusion and MIC for salmonella species. According to CLSI 2012 interpretive criteria, on disk diffusion testing 13 isolates were sensitive, 13 were resistant and 74 were intermediate to ciprofloxacin. On MIC, 55 strains were resistant showing MIC ≥1µg/ml and 45 isolates were intermediate showing MIC 0.125-0.5µg/ml. No isolate was found sensitive to ciprofloxacin according to CLSI 2012 interpretive criteria.Conclusion: In conclusion, the present study showed the value of nalidixic acid susceptibility as an indirect but a certain marker of ciprofloxacin susceptibility. Nalidixic acid resistant showed increased minimum inhibitory concentration (MIC) by agar dilution method.

Study of antibiotic resistance in patients of enteric perforation in a tertiary care hospital.

“…Recommendations have been made that since these strains are susceptible to imipinems and azithromycin, the susceptible patients should be treated with these antibiotics as first line medications rather than the standard empirical treatment. 24 Not only this but the wound infection rates in the patients who had been infected with resistant strains of Salmonella Typhi were significant as compared with the patients with sensitive strains. The probable reason for this is the initial treatment with the empiric therapy failed to curb the infection and by the time culture results arrived and we started the patients on imipenem, the wound infection had already set in.…”

“…Pakistan is one of the few regions of the world where the extensively drug resistant Salmonella Typhihas beenreported. 23,24 The result of these resistant strains has not only posed a burden on our healthcare system but has made us as clinicians unsure if the empirical therapy that we are going to start a patient is going to get the job done effectively. 25 The data collected in this research has shown that ampicillin and Nalidixic acid are no longer nearly enough for this battle against the resistant typhoid strains.…”

Enteric Fever in Patients of Lahore: Association of Positive Blood Cultures with the Typhidot Immunoassay Tests and Widal Agglutination

“…Previous studies have shown that the majority of TYP-CN patients have typhoid fever, but culture avoids them (12). Therefore, serological information is trusted, and the most commonly used traditional method is broad agglutination with the advantages of low cost and easy conductivity (13).Although culture (blood, bone marrow) remains the gold standard, rapid and accurate laboratory analysis for typhoid fever is clearly needed, because the presentation is poorly identifiable and can vary significantly in patients, especially children (14,15). Widal may be misunderstood because of possible "lower" agglutinins that have not been inoculated and the immunoassay point has limited specificity only for S. typhi.…”