Sabah Ibrahim Shaaban

Background: Listeria monocytogenes is a foodborne pathogen of a major public health concern due to its ability to cause severe illness and its increasing antimicrobial resistance. This study aimed to determine the prevalence, antimicrobial susceptibility, serotype distribution, and virulence genes profiles of L. monocytogenes isolated from food products, farm animals, and humans in Egypt. Methodology: A total of 750 samples were collected, including dairy products, raw meat, animal fecal samples, aborted fetuses, and human stool samples. Isolation and identification were performed according to ISO, (2022) followed by serotyping and molecular characterization of virulence genes ( iap , hlyA , and actA ). Antimicrobial susceptibility testing was conducted using the disk diffusion method according to CLSI guidelines. Results: Listeria spp. were detected in 18.5% of food products, 4.75% of animal fecal samples, 18.0% of aborted fetuses, and 17.0% of human samples. The highest contamination rates were observed in Kareish cheese (28.0%) and raw milk (22.0%). Serotype 4b was the most prevalent among isolates. All isolates harbored the iap gene, while the hlyA and actA genes were detected in 80% and 67% of isolates, respectively. Alarmingly, all isolates were resistant to clindamycin and nalidixic acid, and high resistance rates were observed against penicillin (93.3%) and ampicillin (86.7%), although imipenem and amikacin remained effective. Conclusion: These findings highlight the circulation of multidrug-resistant and virulent L. monocytogenes strains in Egypt’s food chain and among occupational groups. Enhanced hygiene measures, continuous surveillance, and prudent antibiotic use are urgently needed to mitigate the associated public health risks.

Mastitis in dairy cattle is one of the most frequently diagnosed diseases worldwide. The chief etiological agents of mastitis are bacteria of the genus Streptococcus spp. Streptococci are frequently isolated from bovine mastitis in dairy cows . Antibiotics used to treat bacterial infections can become ineffective over time due to emergence of antibiotic resistant pathogens, with the advent of nanotechnology, silver nanoparticles (AgNPs) have gained significant attention as a therapeutic agent due to the well-known antimicrobial properties of silver. the aim of our study was to show an In vitro investigation of the efficacy of some antibacterial drugs against streptococcus isolated from mastitis in dairy cattle and also to show the effect of AgNPs and AgNPs -loaded penicillin on that isolate. In the current study, Antibiotic resistance profiles in streptococcus spp. and resistance genes against penicillin and gentamycin was detected for Pbp1A target gene and aac (6') aph (2'') target gene, respectively, penicillin was loaded onto AgNPs, thus enhancing penicillin antibacterial activity against streptococci. The prepared AgNPs and their conjugates were characterized by Transmission electron microscopy (TEM) and Zeta potential analysis. The minimum inhibitory concentration (MIC) of AgNPs and their conjugates were also determined. The results explained that the lowest concentration that inhibited the growth of streptococcus spp. was 50 PPM for AgNPs, while 12.5 PPM for AgNPs loaded penicillin by agar plate diffusion method. Inclusive, according to that results , the new nanocomposite, AgNPs -loaded penicillin, showed the highest antibacterial effects, against tested pathogenic bacteria, compared to penicillin alone.

The current work was carried out in El-Beheira Province, Egypt to estimate the frequency of Candida species occurrence in mastitic milk of cattle and buffalo as well as oral swabs from humans besides detection of some virulence factors and determine the antifungal susceptibility of the obtained Candida strains. A total of 350 raw milk samples were randomly collected from clinically mastitic bovine milk. Also, 140 oral swabs were obtained from patients attending external clinics of El-Delingat Hospital to be examined for the presence of Candida. The recorded results showed a high frequency of Candida spp. (36.9%) among the examined milk samples. Candida spp. isolated from cow milk (39.9%) was higher than that isolated from buffalo milk (29.3%). Also, the total prevalence of Candidiasis in human samples was 62.9% and the highest prevalence in relation to age groups was noticed in the age group > 2 - < 16 years (65.5%) and finally, the age group >40 years (58.8%). The identified Candida spp. in human samples were C. albicans (37.5%), C. glabrata (17.1%), C. krusei (14.8%), C. parapsilosis (13.6%), C. tropicalis (11.4%), C. guilliermondii (4.5%) and C. kefyr (1.1%). It was observed that the highest prevalence of Candida species was among artificially fed infants (77.8%) and the lowest prevalence was detected in breastfed infants (53.3%). Based on the recorded results, Candida species constitute a major threat to both dairy animals and humans. Also, improperly heated milk constitutes a potential source of infection for humans so efficient pasteurization must be performed to avoid this risk.

Thank you for giving me the opportunity to participate in the review of the manuscript entitled "Clinical and Subclinical Bovine Mastitis: Staphylococcus aureus Isolation and Identification from Dairy Farms Located in and Around Hawassa Town, Souther...

Background: Helicobacter pylori is one of the most common bacterial infections and is widespread globally. It causes a variety of gastrointestinal disorders, though a great proportion of infections are asymptomatic. A total of 143 fresh stool samples were collected from apparently healthy farm and pet animals (43 cattle, 50 buffaloes, 50 sheep, 50 dogs, and 50 cats), in addition to 768 human stool samples. The samples were examined using stool antigen and rapid antibody tests, and further confirmation of glmM “human antigen-positive samples and animal milk samples” was conducted by polymerase chain reaction (PCR). Results: The prevalence rates of H. pylori infection in animals were 22.2% and 16% in antibody and stool antigen tests, respectively. The detection rates were 28%, 24%, 12%, 10%, and 4.7% in cats, dogs, buffaloes, sheep, and cattle, respectively. On the other hand, the prevalence rate of H. pylori infection in human stool samples was 74.8%, and a statistically significant association was observed between prevalence and several factors, such as sex, age, and locality. PCR was performed to detect the glmM gene of H. pylori, and this gene was found in 21 of 27 human antigen-positive samples and 5 of 13 animal milk samples. Conclusions: H. pylori was detected in both human and animal samples. Furthermore, glmM was found in milk and human samples. Our findings suggest that pet and farm animals could transmit H. pylori infection to humans.

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae are a universal public health alarm frequently identified among humans, animals, and poultry. Livestock and poultry production are a possible source of multidrug-resistant microorganisms, including ESBL-producing Enterobacteriaceae, which confer antimicrobial resistance to different β-lactam antimicrobial agents. From January to May 2020, a cross-sectional study was carried out in three dairy cattle farms and four poultry farms in different districts of northern Egypt to assess the prevalence of ESBLs, AmpC beta-lactamase-producing E. coli and Klebsiella in livestock, poultry, and human contacts, and to investigate the genetic relatedness of the recovered isolates. In total, 140 samples were collected, including human fecal samples (n = 20) of workers with intimate livestock contact, cattle rectal swabs (n = 34), milk (n = 14), milking machine swabs (n = 8), rations (n = 2), and water (n = 2) from different cattle farms, as well as cloacal swabs (n = 45), rations (n = 5), water (n = 5) and litter (n = 5) from poultry farms. The specimens were investigated for ESBL-producing E. coli and Klebsiella using HiCrome ESBL media agar. The agar disk diffusion method characterized the isolated strains for their phenotypic antimicrobial susceptibility. The prevalence of ESBL-producing Enterobacteriaceae was 30.0%, 20.0%, and 25.0% in humans, cattle, and poultry, respectively. Further genotypic characterization was performed using conventional and multiplex PCR assays for the molecular identification of ESBL and AmpC genes. The majority of the ESBL-producing Enterobacteriaceae showed a multi-drug resistant phenotype. Additionally, bla_SHV was the predominant ESBL genotype (n = 31; 93.94%), and was mainly identified in humans (n = 6), cattle (n = 11), and poultry (14); its existence in various reservoirs is a concern, and highlights the necessity of the development of definite control strategies to limit the abuse of antimicrobial agents.

This study aims to determine the prevalence of STEC in she-camels suffering from mastitis in semi-arid regions by using traditional culture methods and then confirming it with Serological and molecular techniques in milk samples, camel feces, as well as human stool samples for human contacts. In addition, an antibiotic susceptibility profile for these isolates was investigation. Mastitic milk samples were taken after California Mastitis Test (CMT) procedure, and fecal samples were taken from she-camels and human stool samples, then cultured using traditional methods to isolate Escherichiacoli. These isolates were initially classified serologically, then an mPCR (Multiplex PCR) was used to determine virulence genes. Finally, both camel and human isolates were tested for antibiotic susceptibility. Out of a total of 180 she-camels, 34 (18.9%) were mastitic (8.3% clinical and 10.6% sub-clinical mastitis), where it was higher in camels bred with other animals. The total presence of E. coli was 21.9, 13.9, and 33.7% in milk, camel feces, and human stool, respectively, whereas the occurrence of STEC from the total E. coli isolates were 36, 16, and 31.4% for milk, camel feces, and stool, respectively. Among the camel isolates, stx₁ was the most frequently detected virulence gene, while hlyA was not detected. The most detected virulence gene in human isolates was stx₂ (45.5%), followed by stx₁. Camel STEC showed resistance to Oxytetracycline only, while human STEC showed multiple drug resistance to Amoxicillin, Gentamycin, and Clindamycin with 81.8, 72.7, and 63.6%, respectively. Breeding camels in semi-arid areas separately from other animals may reduce the risk of infection with some bacteria, including E. coli; in contrast, mixed breeding with other animals contributes a significant risk factor for STEC emergence in camels.