Enteric fever is a major public health problem in India. The emergence of multi drug resistant Salmonella typhi (resistant to Ampicillin, Chloramphenicol, Cotrimoxazole) led to use of Quinolones (Ciprofloxacin, Ofloxacin) as the first line of drug for treatment.
Microbiology, Bhatia Hospital, Mumbai. Founded in 1932, Bhatia hospital is a tertiary care hospital and a premier teaching institute. All the isolates of Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi A from blood cultures of patients suspected of enteric fever between August 2008 and July 2010 were included in the study. Identification was done by standard biochemical tests and by agglutination with antisera (Remel). Antibiotic sensitivity pattern was determined using Kirby Bauer disc diffusion method (CLSI criteria).
We obtained 211 S.typhi and 24 S.paratyphi A isolates. The sensitivity pattern of the isolates was as per Figure 1. For S.typhi, 98.5% resistance was seen for Nalidixic acid. High resistance to Ciprofloxacin and Ofloxacin was also seen. High sensitivity was seen for Chloramphenicol (92.25%) and Cotrimoxazole (80%). For S.paratyphi A, 100% resistance was seen to Nalidixic acid while 60% resistance to Ciprofloxacin and Ofloxacin was observed. High sensitivity was seen for Chloramphenicol (76%) and Cotrimoxazole (93%). All isolates showed 100% sensitivity to Ceftriaxone, Cefexime, Ceftazidime, Cefotaxime and Cefepime. It is noteworthy to see that the isolates showed high sensitivity (Fig.1) to Chloramphenicol and Cotrimoxazole.
Increase in resistance to Nalidixic acid has been reported1 . Nalidixic acid resistance is a marker for predicting low level resistance to Ciprofloxacin Reports of sensitivity to Chloramphenicol are variable from different regions; our experience among S.typhi and also an indicator of treatment failure to Ciprofloxacin2 .
indicates very high sensitivity as do Krishnan et al3 . With increasing resistance to Fluoroquinolones and the possibility of re-emergence of sensitivity to Chloramphenicol among Salmonellae, the policy of empirical therapy of enteric fever needs to be rationalized. The changing trends in antibiograms of S.typhi and S.paratyphi A, probably requires reconsideration for use of Chloramphenicol in select cases of typhoid fever instead of Ciprofloxacin or 3rd and 4th generation Cephalosporins to prevent the emergence of multidrug resistance.
Acknowledgement: We are thankful to Dr K.H.Sahiar, Head, Department of Pathology for his valuable suggestions and guidance during this study.
- S Joshi, C Wattal, A Sharma, JK Oberoi, KJ Prasad. Quinolones – Drug of choice in Enteric fever? Indian J Med Microbiol 2004;22:271-72
- V Lakshmi, R Ashok, J Susmita, VV Shailaja. Changing trends in the antibiograms of Salmonella isolates at a tertiary care hospital in Hyderabad. Indian J Med Microbiol 2006;24:45-48
- P Krishnan, M Stalin, S Balasubramanian. Changing trends in antimicrobial resistance of Salmonella enterica serovar typhi and Salmonella enterica serovar paratyphi A in Chennai.Indian J Pathol Microbiol 2009;52:505-08