Seasonal variation in bacterial pathogens isolated from stool samples in Karachi, Pakistan

To determine the seasonal variation of the commonly isolated bacterial pathogens in stool samples. A retrospective descriptive study was undertaken of all the stool samples submitted from within Karachi to the Aga Khan University Hospital Laboratory over a period of five years [January 1997- December 2001] in order to determine the commonly isolated bacterial pathogens and to predict their seasonal variation. A total of 16379 stool samples were included in this review. Bacterial isolates were found in 6670 stool samples [culture detection rate=40.7%]. The mean age at the time of culture of each sub-group was <1 year group [6.58 +/- 3.1 months], 1-5 years [2.13 +/- 0.94 years], 5-14 years [8.3 +/- 2.6 yrs] and adults [43.2 +/- 18.5 years]. Male: Female ratio was 1.2:1. Vibrio cholera 01 Ogawa [32.8%], Campylobacter jejuni [17.3%], Enteropathogenic Escherichia coli [9.9%], Salmonella paratyphi b [6.6%] and Shigella flexneri [6.2%] were the most common organisms isolated. These organisms show a distinct seasonal variation with summer predilection. In contrast to the previous studies from South Asia, which have identified E. coli, followed by Vibrio cholerae as the most common enteric isolates, we found Vibrio cholera 01 Ogawa followed by Campylobacter jejuni as the most common enteric pathogens isolated in an urban setting. It is important to consider seasonal variation when empirically treating diarrheal diseases in our region

Antibiotic prophylaxis in paediatric surgery

Effect of antibiotic prophylaxis was studied in 400 children undergoing various types of surgery. Patients were divided into different classes according to the type of operation and each was further randomized into a routine or trial group. The routine group received antibiotics for prolonged periods. In the trial group, "clean" cases [class A] did not get any antibiotics. The "clean-contaminated" [class B] and "contaminated" cases [class C] received peri-operative antibiotics only. Frankly infected cases were not included in this trial. There were 131,213 and 56 cases in classes A, B and C respectively; of these 13 [3.25%] cases were diagnosed as infected, four in the trial group and nine in the routine group. It was found that a short course of peri-operative antibiotics was equally, if not more effective. Prolonged courses of antibiotics were not only useless and expensive but could also be harmful. For clean cases there is no need for antibiotic prophylaxis. Children behave no differently and these results may be extrapolated to adults