The College of Veterinary Medicine at the University of Baghdad hosted a Master’s thesis defense titled “Detection of Listeria spp in Cases of Human Diarrhea, Aborted Cattle, and Cattle with Mastitis in Baghdad” by researcher Sabah Adel Mahmoud.
The study aimed to detect Listeria in human diarrhea samples, milk from cows with clinical mastitis, as well as fetuses and milk from aborted cows in Baghdad during the period from September 2023 to May 2024.
The research involved analyzing 100 stool samples from individuals with diarrhea, 50 milk samples from cows with mastitis, 50 aborted bovine fetuses, and 50 milk samples from the same aborted cows. The detection of Listeria was performed using conventional culture methods, biochemical tests, and the Vitek 2 automated system.
The study also assessed the antibiotic resistance of isolated Listeria strains using the disk diffusion method against eight antibiotics. Furthermore, it examined the presence of virulence genes (prfA, actA, and hylA) in Listeria isolates.
The findings revealed the presence of L. monocytogenes in pediatric diarrhea cases, clinical mastitis, and aborted fetuses, demonstrating virulence factors and antibiotic resistance. Additionally, the high antibiotic resistance of L. innocua in mastitis milk suggests a potential risk to human health and economic losses in dairy cattle farming.
The researcher concluded that ISO methods, cold enrichment, and selective media are effective for isolating Listeria spp. and that Vitek 2 is a reliable tool for species-level identification. Moreover, polymerase chain reaction (PCR) is a successful technique for species-specific identification, producing results consistent with initial isolation methods.
The study recommended conducting broader research on Listeria spp. in cases of mastitis and abortion in other animal species. It also emphasized the need for further investigations into Listeria spp. in human cases and additional studies on the pathogenic potential of L. innocua in both human and animal infections.