World Health Organization classified Listeria monocytogenes as a major notable foodborne pathogen associated with high mortality and hospitalization. The study reports the prevalence, antibiogram, virulence determination and genetic characterization of L. monocytogenes from different food products. A total of 250 food samples, fifty samples each from raw milk, ice cream, minced meat, fish fillet and sausage were collected from the Menoufiya governorate in Egypt. L. monocytogenes was detected in 17 (6.8%) of the tested food samples including minced meat (14%), fish fillet (8%), sausage (6%) and raw milk (6%). The antimicrobial susceptibility assay of 17 L. monocytogenes isolates against seventeen antibiotics belonging to eight antibiotics classes revealed a high susceptibility to norfloxacin (82.3%), amoxicillin-clavulanic acid (76.4%), cefotaxime (70.5%), erythromycin (64.6%), amoxicillin (64.6%), gentamicin (58.7%) and vancomycin (58.7%). While, high resistance was observed against oxytetracycline (76.4%), trimethoprim-sulfamethoxazole (76.4%), chloramphenicol (70.5%), doxycycline (64.6%), levofloxacin (41.2%) and azithromycin (41.2%). Of note, all L. monocytogenes isolates were multidrug-resistant. The multiplex PCR successfully amplified L. monocytogenes in all tested isolates. Screening of the five virulence-related genes revealed the hlyA and iap as the most prevalent genes followed by actA gene, however, the inlA and prfA genes were not detected in any of the studied isolates. The partial 16S rRNA gene sequencing of three L. monocytogenes isolates showed a high nucleotide similarity (99.1–99.8%) between the study isolates and various global clones, and phylogenetic analysis clustered these L. monocytogenes strains with other Listeria species including L. welshimeri, L. seeligeri and L. innocua. This study demonstrates the impact of L. monocytogenes as a major contaminant of various food products and suggests more attention to the awareness and hygienic measures in the food industry.

Methicillin-resistant Staphylococcus aureus (MRSA) strains have veterinary and public health importance as they are responsible for a wide range of difficult to treat infections and food poisoning. Two hundred samples (50 samples each of minced meat, beef luncheon, Karish cheese, and human samples (pus swab from open wounds)) were cultured, and MRSA strains were identified using disk diffusion tests and mecA gene-based PCR. A total of 35% (70/200) of the examined samples were confirmed as coagulase-positive S. aureus in minced meat (46%), beef luncheon (44%), Karish cheese (44%), and human samples (22%). The MRSA strains showed resistance to amoxicillin (91.4%), penicillin (97.1%), cefoxitin (85.7%), cephradine (82.9%), tetracycline (57.2%), and erythromycin (52.8%). More than half of the tested S. aureus isolates harbored the mecA gene. The sequence analysis of the mecA gene from the minced meat, Karish cheese, and human samples revealed high genetic similarities between the S. aureus isolates from these sources. In conclusion, our findings indicate a risk for the transmission of the mecA gene of S. aureus across the food chain between humans and animal food products. Further studies should focus on finding additional epidemiological aspects of the MRSA strains in food chain.

Bovine respiratory disease (BRD) is a complex syndrome associated with high mortality in young calves and causes severe economic losses in the cattle industry worldwide. The current study investigated the prevalence and molecular characterization of common bacterial pathogens associated with respiratory symptoms in young calves from Sadat City, one of the largest industrial cities in Menoufiya Governorate, Egypt. In between December 2020 and March 2021, 200 mixed-breed young calves of 6–12 months were examined clinically. Of them, sixty (30%) calves showed signs of respiratory manifestations, such as coughing, serous to mucopurulent nasal discharges, fever, and abnormal lung sound. Deep nasal (Nasopharyngeal) swabs were collected from the affected calves for bacteriological investigation. Phenotypic characterization and identification revealed Mycoplasma bovis, Mycoplasma bovigenitalium, Pasteurella multocida, and Staphylococcus aureus in 8.33%, 5%, 5%, and 5% of the tested samples, respectively. The PCR technique using species-specific primer sets successfully amplified the target bacterial DNA in all culture-positive samples, confirming the identity of the isolated bacterial species. Partial gene sequencing of 16S rRNA gene of M. bovigenitalium, P. multocida, and S. aureus, and mb-mp 81 gene of M. bovis revealed high nucleotide similarity and genetic relationship with respective bacterial species reported from Egypt and around the world, suggesting transmission of these bacterial species between animal host species and localities. Our study highlights the four important bacterial strains associated with respiratory disorders in calves and suggests the possible spread of these bacterial pathogens across animal species and different geographic locations. Further studies using WGS and a large number of isolates are required to investigate the realistic lineage of Egyptian isolates and globally.

Salmonellosis is recognized as an important health problem and a major challenge in poultry industry worldwide. This study highlight the prevalence rate of salmonella serotypes in chickens as well as demonstration of some critical virulence genes by using specific primers sets in PCR reaction. Out of 100 freshly dead chickens, sixteen chicken samples were positive to Salmonella with 16% prevalence rate.The rate of recovery of Salmonellae from the different internal organs showed that the intestine is the most predication seat followed by, heart and liver with (8%), (6%) and (2%), respectively. Salmonella isolates (16) from chickens were serotyping using O and H antigen. The results revealed that S. Enteritidis was the most serotype found in 5 isolates (31.25%) followed by S.Infantis in 4 isolates (25%). Both S.Newlands and S.Kentucky found in 2 isolates 12.5%. Each of S.Ferruch, S.Weybridge and S.Naestved have one isolate (6.25%).The application of PCR for detection of invA, avrA and stn virulence genes in nine salmonella serovars revealed that these genes (invA, avrA and stn)were detected in 100% of tested strains except S. Naestved does not contain stn gene. Hence, this study recommends that PCR may be used for rapid and sensitive detection of Salmonella and help in understanding the role of these genes in pathogenicity of salmonella infection in poultry.

Colibacillosis is a fetal and serious problematic disease particularly in young calves duringthe first days of their life accompanied with high mortality losses. The aim of this study isto moleculary characterize Escherichia coli (E. coli) strains isolated from individual cases ofneonatal calf diarrhea. Characteristic clinical symptoms as yellowish diarrhea with lowcolostrum feeding history was observed during samples collection. Rectal swabs wereobtained from 50 healthy and 100 clinically infected diarrheic calves which identified bytraditional bacteriological and serological procedures. Then, E. coli isolates were subjectedfor genetic characterization of virulence genes (stx1, stx2, fimH, iutA, eaeA and tsh) usingboth uniplex and multiplex PCR. The most dominant virulence gene was fimH in all theexamined isolates followed by iutA in 50% however, the eaeA and tsh genes were in 37.5%while no detection for both stx1 and stx2 genes. In conclusion, these results provideupdated information regarding the molecular detection of E. coli strains from neonatalcalves in Egypt and thus, would be important to formulate preventing tools and effectivetherapy against E. coli either in Egypt and or worldwide.