Prevalence, Seasonal Fluctuation, and Molecular Profiles of Bacterial Enteropathogens Causing Diarrhea in Cats in Karbala, Iraq
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Background: Information on the presence of intestinal pathogens is very scarce. Consequently, this research work aimed at isolating and characterizing the primary bacteria that cause feline diarrhea in Karbala, studying their monthly prevalence, and registering their molecular information in the GenBank database. Methodology: One hundred clinical samples including rectal swabs and fresh feces were collected from symptomatic cats with diarrhea from different ecological zones in Karbala Governorate during an uninterrupted period of six months from October 2025 to March 2026. Preliminary bacterial isolation and identification were done using common bacterial enrichment media and selective differential media. Identification at the species level was done using the extraction of DNA from isolated bacteria followed by amplification through polymerase chain reaction (PCR) using conserved DNA sequences unique to Pseudomonas oryzihabitans, Escherichia coli, Salmonella enterica, Stenotrophomonas maltophilia, Citrobacter braakii, and Enterobacter cloacae. The genetic characterization of the identified bacteria was achieved through the Sanger sequencing of selected PCR-positive clones. The generated sequences were then analyzed against available nucleotide sequences in NCBI using BLAST and submitted to GenBank for the generation of accession numbers. Results: The molecular detection revealed that 67 of the 100 samples (67.0%) were positive to one of the enteropathogenic bacteria investigated. Out of the positive samples, Pseudomonas oryzihabitans was the most common bacterial species with the prevalence of 17.0% (n=17), followed by classic zoonotic bacteria Escherichia coli, which had the prevalence of 16.0% (n=16) and Salmonella enterica subsp (14.0% or n=14). Opportunistic and nosocomial pathogens were present less frequently: Stenotrophomonas maltophilia (8.0%, n=8); Citrobacter braakii (7.0%, n=7) and Enterobacter cloacae (5.0%, n=5). Seasonal fluctuations were detected during the time; October 2025 demonstrated the maximum peak of the infection (19 positive cases), whereas secondary peaks were found in December (13 cases) and March 2026 (11 cases), with the lowest rates in November and January, when only 7 positive cases were recorded. Conclusion: In this research work, it is clear that the bacterial pathogens are responsible for feline diarrhea in Karbala, with P. oryzihabitans, E. coli, and Salmonella being the primary bacteria causing the infection. The dramatic increase in the incidence of infections in October means that there is the critical danger associated with the change in weather in autumn, probably caused by the climatic factors which result in the physiological stress and weaken animals' immune systems. Also, the successful deposit of the sequences in the GenBank means that the basic data on the genetics of feline enteric bacteria in Iraq have been created.
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