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

Area of Science:

• Microbiology
• Infectious Diseases
• Public Health

Background:

• Enteric bacterial infections are a significant cause of diarrheal diseases globally.
• Understanding the seasonal patterns of common bacterial pathogens is essential for effective public health interventions.
• Previous studies in South Asia have indicated different patterns of prevalent enteric pathogens.

Purpose of the Study:

• To identify the most frequently isolated bacterial pathogens from stool samples.
• To determine the seasonal variations in the occurrence of these pathogens.
• To compare findings with previous research from the South Asian region.

Main Methods:

• A retrospective analysis of 16,379 stool samples submitted to a hospital laboratory over five years (1997-2001).
• Identification and quantification of bacterial isolates from stool cultures.
• Statistical analysis to determine pathogen prevalence and seasonal distribution.

Main Results:

• Bacterial pathogens were detected in 40.7% of the analyzed stool samples.
• The most common isolates were Vibrio cholera 01 Ogawa (32.8%), Campylobacter jejuni (17.3%), and Enteropathogenic Escherichia coli (9.9%).
• These pathogens exhibited a distinct seasonal variation, with a higher incidence during the summer months.

Conclusions:

• Vibrio cholera 01 Ogawa and Campylobacter jejuni were identified as the predominant enteric pathogens in this urban setting, differing from previous South Asian studies.
• The study highlights the importance of considering seasonal patterns when initiating empirical treatment for diarrheal diseases in the region.
• Findings contribute to a better understanding of enteric pathogen epidemiology and inform public health strategies.