Trends Of Antibiotic Susceptibility Of Salmonella Enterica Serovar Typhi And Paratyphi In An Urban Hospital Of Dhaka City Over 6 Years Period

Abstract

The antibiotic resistance pattern of salmonella is ever changing over time. The present study is a retrospective analysis of rate of isolation of Salmonella Typhi and Paratyphi and their antibiotic resistance pattern over 6 years period in an urban hospital of Dhaka city. Blood culture submitted in BIRDEM hospital from 2004-2009 were analyzed. Isolated Salmonella sp were identified and antimicrobial susceptibility testing was carried out by a standard disc diffusion method.Among 385 isolated Salmonella sp 304 (79%) were Salmonella enterica serovar Typhi and 81 (21%) were Salmonella enterica serover Paratyphi A. The rate of isolation of S. Paratyphi A has increased over 6 the year period from 14% to 24%. Resistance to individual first line anti-salmonella drugs has increased from 2004 to 2006 (42 to 63%) but has decreased thereafter. Similar pattern was found when simultaneous resistance to three first line antibiotics namely ampicillin, chloramphenicol and co-trimoxazole were considered. Out of total 304 S. Typhi, 117 (38%) were simultaneously resistant to all three first line drugs compared to only 1.8% S. Paratyphi A. Analysis showed that 80 to 90% of isolated S. Typhi was nalidixic acid resistant (NARST) with reduced susceptibility to ciprofloxacin while the rate for S. Paratyphi A was 71-94%. All S. Typhi and Paratyphi A were sensitive to ceftriaxone. The study showed that there was a gradual decline of resistance of S. Typhi to first line antibiotics but very high prevalence of nalidixic acid resistant S. Typhi and S. Paratyphi in Bangladesh.Ibrahim Med. Coll. J. 2011; 5(2): 42-45

Pattern of Antibiotic Sensitivity in Enteric Fever: A Tertiary Care Hospital Experience

“…5 Cefixim, ciprofloxacin and levofloxacin were sensitive in significant number of cases, but much lower than previous studies. 11 Nalidixic acid resistance is increasing.…”

“…Not a single patient was resistant to ceftriaxone in our study although ceftriaxone resistance has been reported from Bangladesh. 5,6 Significant number of patients were resistant to azithromycin as seen in other studies. 10 Its dosing convenience, easy availability and non-judicious use in non-specific febrile illness might be the contributory factor behind it.…”

“…It is recommended that ciprofloxacin, in contrary to previous statements, should no longer be used if the organism is resistant to nalidixic acid. 3,5 Our study had some limitations. In all samples, sensitivity to all 1 st line antibiotics were not tested.…”

“…3 In this current study we found that significant number of cases were multi-drug resistant, which is much lower than previous studies. 2,4,5 One explanation might be that, as 1 st line drugs are not used in enteric fever because of high resistance rate,so they are regaining their sensitivity. Not a single patient was resistant to ceftriaxone in our study although ceftriaxone resistance has been reported from Bangladesh.…”

“…3 It is reported that more than half of enteric fevers are due to multi-resistant strains of S. typhior paratyphi, moreover resistance to quinolones and cephalosporins are also increasing in Bangladesh. [4][5][6] So, empiric prescription of antibiotics for suspected typhoid fever does not remain uniform, rather isolation of organism and identification of antibiotic sensitivity is desirable before starting antibiotic treatment. In this current study, we have tried to evaluate antibiotic sensitivity patterns of S. typhi and S. paratyphi in our setting.…”