Etiological structure of pathogenic microorganisms in acute diarrhea diseases

Abstract

Introduction. Acute diarrheal diseases (ADD) are a growing public health concern worldwide, with around two billion cases reported annually, mostly in developing countries. In Moldova, 16,000–20,000 cases occur each year, affecting both children under five and adults. Accurate identification of the causative pathogens is essential for controlling transmission and guiding effective treatment. Purpose of the study. This study aimed to identify and characterize the etiological structure of pathogenic microorganisms causing acute diarrheal diseases, based on laboratory investigations at the MTA Buiucani Public Health Medical Institution (PHMI), Chisinau municipality. Material and methods. The study was conducted from 2011 to 2024 at the microbiological laboratory of the MTA Buiucani PHMI, involving 14,335 clinical samples. Bacteriological analysis involved isolating pure pathogen cultures and characterizing them. Etiological confirmation of the disease was performed through coproculture, in accordance with the methodological guideline no. 7 of 24.08.2012, “Microbiological Diagnosis of Intestinal Infections”. Results. Of the 14,335 clinical samples collected from patients with acute diarrheal diseases, 2,976 strains were identified, corresponding to 14 pathogenic microorganisms: Shigella spp., Salmonella spp., Klebsiella spp., Enterobacter spp., Proteus spp., Citrobacter spp., Escherichia coli with haemolytic properties, Morganella spp., Serratia spp., Providencia spp., Hafnia spp., Pseudomonas aeruginosa, Acinetobacter spp., and Aeromonas spp. Positive results were recorded annually, with the highest prevalence observed for Klebsiella spp. (40.63%), while other pathogens ranged from 0.07% (Acinetobacter spp.) to 12.8% (Citrobacter spp.). Hafnia spp. was isolated only in 2023, accounting for 0.17% of that year's isolates. During the study period, the proportion of positive cases varied between 3.53% (2020) and 9.95% (2013), except in 2024 when a peak value of 13.71% was recorded. The lowest rate in 2020 (3.53%) coincided with the implementation of stricter sanitary and epidemiological measures in institutions and public transport. These findings highlight that adherence to personal hygiene practices remains a key factor in preventing acute diarrheal diseases. Conclusions. Over the study period, 14 distinct etiological agents of acute diarrhea were identified. Positive cases were reported annually, with Klebsiella spp. being the predominant pathogen in the Buiucani sector of Chisinau municipality. The positivity rate remained relatively stable, peaking significantly in 2024. To reduce the incidence of acute bacterial diarrhea, sustained surveillance and the implementation of effective infection prevention and control strategies are essential.