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 ? 1?g/ml which means that they were
susceptible while 55 strains were intermediate having MIC 2?g/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 ?1?g/ml
and 45 isolates were intermediate showing MIC 0.125-0.5?g/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.
Keyword :
ntibiotic resistance, Typhoid fever, Nalidixic acid resistant, ciprofloxacin susceptibility