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Colibacillosis is the main trouble confronted in cattle outputting, causing considerable economic losses. The infected or carrier calves and cows shed the bacteria in the feces and causing the transmission of pathogenic E. coli to calves at the environment. Diagnosis of E. coli infection in calves relies on history, clinical signs, the culture of bacteria, and serotyping of bacteria. Colibacillosis requires immediate response to colibacillosis is variable, centered on isolation and treatment of dehydration &antimicrobial therapy. Parental antibiotics can give a good result if given in the early stage, but not without rehydration therapy. The prevalence of colibacillosis differs from 5.4 to 100%, and it is roughly estimated that calf mortality connected with colibacillosis of 20% may reduce net profit to 40%. The emergence of multi-drug resistant E. coli isolated from diarrhetic calves has been raised as a new concern for public health and food safety authorities. Routine monitoring of E.coli isolated from diarrhetic calves will help reduce the transmission to humans and help select the most effective antibiotics. In conclusion, dam vaccination before calving, improve hygiene around calving and proper colostrum administration considered the main factors to control and prevent the disease. In addition, vigilant monitoring of E. coli isolates recovered from diarrhetic calves for antimicrobial sensitivity pattern will help choose the appropriate antibiotic and decrease the transmission of theses isolates to humans.

Aeromonas hydrophila is a major waterborne pathogen, which induces various diseases in freshwater fish with the capability for zoonotic potential. This study was applied to investigate the prevalence of A. hydrophila in diseased Nile tilapia fish, genetic characterization of the virulence encoding genes (act, aerA, alt, and ast genes), and antibiotic susceptibility. Out of the 500 diseased Nile tilapia fish samples, 70% (350/500) Aeromonas species were isolated. From which 53.4% (187/350) of Aeromonas hydrophila strains were identified. A. hydrophila was detected in kidneys, followed by liver, spleen, intestine, and gills. The results of virulotyping displayed the presence of act, and aerA genes in a high percentage of 40%, followed by alt gene (30%), but ast gene was not detected (0%) in A. hydrophila strains. Based on DNA sequence analysis of three virulence associated-genes (act, aerA, and alt genes), the phylogenetic tree showed the genetic relationship with related species. Finally, the antibiotic susceptibility tests revealed high resistance toward chloramphenicol (67.4%), followed by amikacin (51.9%) and gentamicin (47.1%), whereas a high sensitivity was exhibited toward meropenem (90.9%), followed by ciprofloxacin (84.2%), amoxicillin-clavulanic acid (73.3%) and trimethoprim-sulfamethoxazole (64.2%). The multidrug-resistant A. hydrophila strains were observed in 69.0% of strains with six resistance patterns.

This pilot study aimed to characterize Riemerella anatipestifer from ducklings, testing their susceptibility to antimicrobial agents and to detect their virulence markers. Seven R. anatipestifer isolates with 11.67% infection rate were identified out of sixty freshly dead ducklings and confirmed by PCR assay targeting gyrB gene. The gyrB gene sequences of R. anatipestifer isolates were 100% identical to each other and also showed 100% sequence similarity to the published gyrB genes. Four virulence genes namely ompA, prtC, hagA, and sspA were identified in all isolates except sspA was detected in 5 isolates. The antibiogram revealed higher sensitive to imipenem, amikacin, and rifampin, while, a remarkably high resistance was displayed against ampicillin, penicillin, cefipime, trimethoprim/sulfamethoxazole, gentamicin, ceftazidime, streptomycin and cefoperazone. Proper and rapid identification of R. anatipestifer with detection of their antimicrobial susceptibility and its virulence potential is essential for understanding the epidemiology of R. anatipestifer and to apply the effective control strategies.

Calf diarrhea is main causes of mortality among neonatal calves in large-scale cattle operations. The disease syndrome usually associated with severe economic losses. Bacteria represent the common causes of diarrhea in calves. In this study, we are collected one hundred fecal samples from diarrheic mixed-sex neonatal calves aged 1-60 days located at El-Behera Governorate were examined the presence of E. coli by bacteriological tests and further screened for the presence of some virulence encoding genes. Results were showed that 95% were positive for E. coli. The isolates belonged to 9 different serogroups namely O1, O27, O126, O119, O158, O146, O25, O148, and O115. The confirmed isolates were further examining for the existence ofsome virulence encoding genes (stx1, stx2, eaeA, and hlyA). The results appeared that,stx1, stx2, eaeA, and hylA were successfully amplified in 66.6 %,41, 6 %,16.6 %, and 16.6% of the examined isolates, respectively. In conclusion; the comprehensive understanding of the virulence encoding determinants and the subcellular mechanism of E. coli pathogenesis will help develop accurate preventive and curative measures to decrease E. coli induced calf diarrhea in large-scale cattle farms.

Objective: This study was undertaken to determine the prevalence, virulence, and antibiotics susceptibility of Listeria monocytogenes isolated from hindbrain, spinal cord, milk, and intestinal content collected from sheep in the Dakahlia Governorate, Egypt. Design: Observational study. Samples: We analyzed 472 samples, including 72 hindbrain/spinal cord samples from emergency-slaughtered sheep, 300 raw-milk samples from apparently healthy sheep, and 100 intestinal content samples from slaughtered sheep at three abattoirs. Procedures: Isolation and identification of L. monocytogenes were performed using conventional techniques. The biochemically identified isolates were confirmed by 16SrRNA gene sequencing and examined for virulence-associated genes (hlyA and iap) as well as for antimicrobial susceptibility. Results: In total, 16 (3.39%) out of 472 sheep samples [5.56% (4/72) in hindbrain/spinal cord, 4% (12/300) in milk, and 0% (0/100) in intestinal content samples] were found to be positive for L. monocytogenes. All the confirmed isolates were positive for the hlyA gene (100%); meanwhile, none of them exhibited the iap gene. Antibiotic susceptibility testing showed high resistance rates to amoxicillin, cefotaxime, erythromycin (50% each), and vancomycin (37.5%). Sulfamethoxazole–trimethoprim and tetracycline resistance rates were 25% and 12.5%, respectively. On the contrary, all isolates were susceptible to amikacin, ciprofloxacin, and norfloxacin. Interestingly, 37.5% (6/16) of L. monocytogenes isolates exhibited multidrug resistance (MDR). The multiple antibiotic resistances (MAR) index of isolates ranged from 0.1 to 0.6. Conclusion and clinical relevance: Our data highlights the importance of awareness of virulent strains of MDR L. monocytogenes of sheep samples and potentially samples from other domestic animals in Egypt.

Objective: The aim of the present study was to isolate and identify mold species from poultry farms with detection of their virulence potential, biofilm formation capability and to perform antifungal susceptibility testing to some representative isolates. Design: Observational study. Animals: Fifty freshly dead broiler chicks were included in this study. Procedures: A total of 250 samples were collected from 50 diseased chicks (5 samples each), including lung, liver, kidney, heart, and tracheal swap. In addition, litter samples were collected from 7 poultry farms and were subjected to mycological examination. The isolated mold species have been tested for hemolytic activity, catalase, amylase, lipase, and biofilm production activity; besides, detection of virulence genes (rhbA, fos-1, and pskB) using PCR assay. . Results: A total of 208 mold isolates were identified, with five genera; Aspergillus (84.6%), Zygomycetes (12.9%), Acremonium (0.96%), Penicillium (0.96%) and Alternaria (0.48%). Mold isolates displayed various degrees of fungal activities on blood agar plates, catalase activity, amylase activity, lipase activity, and the ability for biofilm production in vitro. Regarding the selected virulence genes, fos-1 was detected in A.fumigatus (3 isolates) and A.flavus (2isolates). While pksP gene was detected in A.fumigatus (7 isolates) and A.niger (2 isolates) and rhbA detected in A. fumigatus (8 isolates) and one isolate of A. flavus of the total evaluated species. The MIC determination provide evidence for the high resistance of all evaluated isolates to nystatin, and a relatively higher sensitivity was displayed by clotrimazole followed by ciclopiroxolamine and tioconazole. Conclusion and clinical relevance: The results reveal that most of the fungal isolates tested displayed enzymatic activity, which are the most effective virulence factors contributing to fungal pathogenicity and high resistance to antifungal, which represents a potential public health concern.

Salmonella is still the major threat to the poultry industry and humans especially that of zoonotic importance. In the present study, a total of 300 samples (liver, intestine, yolk sac and spleen) collected from 100 broiler chickens were examined bacteriologically for the presence of Salmonella. The isolated salmonellae were then screened for virulence encoding genes using multiplex PCR and the antimicrobial susceptibility to antibiotics using disc diffusion method. Results showed that Salmonella was recovered from 5.33% of the examined samples. Sixteen Salmonella serovars were recovered [Salmonella Sinchem (n=3) Salmonella Typhimurium (n=2), Salmonella Gallinarum (n=2), Salmonella Enteritidis (n=2), Salmonella enterica subsp. Salamae (n=1), Salmonella Virchow (n=1), Salmonella Kentucky (n=2), Salmonella Heidelberg (n=1), Salmonella Farsta (n=1) and Salmonella Hydra (n=1)]. Results also showed that all the tested salmonellae (100%) were found harbor the virulence encoding gene specific amplicon of pagC, msgA, spiA, invA, prgH, orgA, sipB, tolC, iroN, lpfC, pefA, sitC, sifA, and sopB. While, only 30% and 70% of the examined salmonellae were harbor cdtB and spvB, respectively. The antimicrobial susceptibility testing of the isolates revealed that most of the isolated Salmonella serovars were expressed multiple antibiotic resistance indexes (MAR) to amoxicillin, doxycycline, chloramphenicol, ampicillin, gentamicin, trimethoprim/sulphamethoxazole. In conclusion, the results of the current study demonstrated that Salmonella isolated from broilers chicken were found to harbor many virulence encoding genes and expressed a high degree of MDR to antibiotics commonly used in human medicine.

Streptococcus agalactiae is a zoonotic human and animal pathogen that causes global economic losses in aquaculture and fatal outcomes in Tilapia. This study aimed to identify S. agalactiae isolated from different fish sources intended for human consumption phenotypically and genotypically and to characterize the virulence-associated genesThree hundred Nile Tilapia fish (Streptococcus agalactiae was detected in 7% (The MDR S. agalactiae detected in raw Tilapia fish pose a significant health hazard to consumers due to their zoonotic characteristics.

Mastitis caused by multi- or pan-drug resistant bacteria is a growing health concern. A total of 110 milk samples were collected: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Enterococcus faecalis, and Escherichia coli were present in 54/110 (49.09%), 37/110 (33.63%), 25/110 (22.72%), 7/110 (6.36%), and 50/110 (45.45%) samples, respectively. A total of 20 methicillin-resistant S. aureus (MRSA) isolates, 19 Streptococcus sp. isolates, and 15 E. coli isolates were selected, and 100% were positive for (coagulase and hemolysins), streptokinase, and hemolytic activity, respectively. A number of 11 E. coli isolates were serotyped, and the serotypes were: O26, O55, O111, O119, O124, O125, O127, and O158. The antimicrobial resistance index ranges for MRSA, Streptococcus sp., and E. coli were 0.49-0.83, 0.39-0.83, and 0.56-1, respectively. The most effective antimicrobials on Gram-positive isolates were cephradine, ciprofloxacin, doxycycline, norfloxacin, and vancomycin, while doxycycline and norfloxacin were effective on E. coli serotypes. All of the selected isolates exhibited slime layer production. The efflux pumps of the 12 MRSA, 12 Streptococcus sp., and 11 E. coli isolates exhibited activity with ethidium bromide concentrations of 1, 1.5, and 0.5 µg/ml, respectively. There was a simultaneous antimicrobial activity of the efflux pump inhibitor chlorpromazine with amoxicillin/clavulanic acid, erythromycin, and oxacillin, to which the isolates were resistant. The 12 MRSA isolates harboured the methicillin resistance genes mec(A,A1, and A2), mecA1, and mecC at frequencies of 9/12 (75%), 9/12 (75%), and 8/12 (66.7%), respectively, and the penicillin resistance gene BlaZ was present at a frequency of 5/12 (41.7%). The distributions of erm(A), erm(B), erm(C), erm(F), erm(G), and erm(Q) were 8/12 (66.7%), 5/12 (41.7%), 12/12 (100%), 2/12 (16.7%), 0/12 (0.0%), and 8/12 (66.7%), respectively. The 12 Streptococcus sp. isolates harboured mec(A, A1, and A2), mecA1, mecC, and blaZ at rates of 4/12 (33.33%), 4/12 (33.33%), 5/12 (41.7%), and 4/12 (33.33%), respectively. The frequencies of erm(A) and erm(F) were 4/12 (33.33%), and 9/12 (75%), respectively. The 11 E. coli isolates harboured the extended-spectrum β-lactamases integrase1, integrase2, blaCTX-M, blaCTX-M-1, and blaTEM at frequencies of 10/11 (90.90%), 11/11 (100%), 9/11 (81.81%), 6/11 (54.54%), and 10/11 (90.90%), respectively. Moreover, the frequencies of erm(A), erm(B), erm(C), erm(F), erm(G), and erm(Q) were 7/11 (63.63%), 4/11 (36.36%), 4/11 (36.36%), 5/11 (45.45%), 10/11 (90.90%), and 10/11 (90.90%), respectively. Our results demonstrated the high antimicrobial resistance of the investigated isolates and confirmed the existence of multiple mechanisms underlying multidrug resistance.

Aim: The objectives of this study were to investigate the prevalence of Yersinia enterocolitica in retail chicken meat, ground and processed beef meat, determine their virulence-associated genes, antimicrobial susceptibility pattern, molecular detection of extended-spectrum β-lactamases, and their capability of biofilm formation in vitro. Materials and Methods: A total of 210 samples (120 retail chicken meat, 30 ground beef, 30 beef burger, and 30 sausage samples) were collected from different retail chicken outlets and markets located at Mansoura city between December 2016 and April 2017. Meat samples were examined bacteriologically for the existence of Y. enterocolitica; bacterial colonies that displayed positive biochemical properties were subjected to polymerase chain reaction targeting 16 rRNA gene. Y. enterocolitica isolates were tested for their susceptibility to six antimicrobial agents using disk diffusion method. Uniplex PCR was used for screening Y. enterocolitica isolates for the presence of two virulence chromosome-associated genes (ail and yst), and β-lactamases (blaTEM and blaSHV). The capability of Y. enterocolitica to form biofilms was detected by tube method. Results: Thirty Y. enterocolitica isolates (14.29%) were recovered including 19 (15.83%) isolates from chicken meat, 3 (10%) from ground beef, 5 (16.67%) from beef burger, and 3 (10%) from sausage samples. Regarding ail gene, it was detected in 6.67% (2/30), while yst gene detected in 20% (6/30) Y. enterocolitica isolates. About 80%, 70%, 63.33%, and 50% of Y. enterocolitica isolates were sensitive to ciprofloxacin, gentamicin, cefotaxime, and streptomycin, respectively, while 83.33% of Y. enterocolitica isolates were resistant to both ampicillin and cephalothin. Interestingly, 21 (70%) isolates had the capability of biofilms formation in vitro. Among the multidrug-resistant (MDR) strains, a significant difference (p

Background: Diabetic kidney disease is the leading cause of chronic kidney disease worldwide. Sodium glucose cotransporter-2 inhibitors may provide a recent solution with better control. Aim: to study the effect of dapagliflozin on glycemic state, lipid profile, renal functions, renal histopathology and some underlying possible mechanisms in type 2 diabetic rats. Methods: Fifty adult male albino rats were divided into five groups: Non-diabetic, diabetic non-treated, diabetic metformin-treated, diabetic dapagliflozin-treatedand diabetic combined metformin & dapagliflozin-treated. Type 2 diabetes was induced by high fat diet-low dose streptozotocin. Metformin or dapagliflozin were given. RBF and RVR were measured. Fasting serum glucose, HbA1c, serum insulin, lipid profile, renal function tests, TAC, MDA and TNF-α were measured then HOMA-IR, LDL-C & creatinine clearance were calculated. Histopathological examination of kidney sections was performed. Results:Hyperglycemia, hyperinsulinemia, insulin resistance, dyslipidemia, impairment of renal functions, altered oxidative and inflammatory modulators status, and changes in renal morphology were observed in diabetic rats. Individual treatment with metformin or dapagliflozin significantly improved those parameters however, better improvement in renal functions was observed in dapagliflozin as compared to metformin-treated groups. Diabetic combined metformin & dapagliflozin-treated group revealed significant improvement in glycemic state, renal function, TNF-α and oxidative stress as compared to dapagliflozin-treated group. Conclusion: Although metformin is better than dapagliflozin in glycemic control, dapagliflozin is more renoprotective than metformin. Combined dapagliflozin and metformin treatment resulted in significant improvement in glycemic state and renal functions in diabetic rats which is better than individual treatment. dapagliflozin had a complementary effect to metformin treatment in T2DM.

Background and objectives Avian mycoplasmosis, particularly Mycoplasma gallisepticum (MG) is one of the infectious diseases associated with economic losses in Egyptian poultry industry. Thus, this study was aimed to determine the prevalence, serological identification, molecular characterization, sequencing and minimum inhibitory concentration of M. gallisepticum isolated from diseased broilers in Egypt. Materials and methods A total of 351 samples (227 tissue samples "tracheas and air sacs" and 124 tracheal swabs) and 71 sera were collected from diseased broilers. The conventional (isolation and biochemical) and molecular methods (PCR) were performed for detection of M. gallisepticum and virulence-associated gene (mgc2). The serum plate agglutination (SPA) test and enzyme-linked immunosorbent assay (ELISA) were applied on sera for determination of the presence of antibodies against M. gallisepticum. The minimal inhibitory concentration test (MIC) was used to determine the sensitivity of two sequenced M. gallisepticum strains to anti-mycoplasma agents. Results The total recovery rate of Mycoplasma from 351 samples from broilers was 45.29% (159) in which M. gallisepticum showed a prevalence of 62.89% (100/159). Serological identification of M. gallisepticum in 71 collected sera using SPA and ELISA were 54.9 and 40.8% with the highest geometric mean titer of ELISA for M. gallisepticum (699.08 and 495.92). Molecular characterization of Mycoplasma using PCR showed that 50% (3/6) of tested isolates were identified as M. gallisepticum based on 16SrRNA. Also, the mgc2 gene was detected in 50% (3/6) M. gallisepticum isolates. Two positive PCR mgc2 specific genes of M. gallisepticum isolates were subjected to gene target sequencing (GTS) to verify that these two isolates were M. gallisepticum. The minimal inhibitory concentration test (MIC) was applied to determine the sensitivity of these two sequenced M. gallisepticum strains to anti-mycoplasma agents. The first M. gallisepticum isolate was sensitive to tilmicosin, tiamulin and spiramycin. The second M. gallisepticum isolate showed sensitivity to tiamulin, spiramycin and tilmicosin. Conclusion These results summarized the necessity of monitoring the Egyptian poultry farms for avian mycoplasmosis. Also, further studies are required for controlling of mycoplasma in all stages of the poultry industry production chain to avoid different losses in Egypt.

Raw milk plays an important role in the survival and transport of pathogenic bacteria including Escherichia coli strains. This study was performed to determine the existence of E. coli in raw milk intended for human consumption and its associated virulence determinants. In this context, a total of 232 milk samples were obtained from different dairy shops located at Mansoura city and its surrounding villages. Milk samples were subjected for bacteriological and serological examination of E. coli. Furthermore, E. coli strains were tested for its haemolytic activity on blood agar plates. The recovered E. coli strains were also screened by Polymerase chain reaction (PCR) for the presence of enterotoxins including heat –labile (LT), heat- stable (ST) toxins and haemolysin (hly) genes. The recovery rate of E. coli was 14.65% (34/232). Among the recovered E. coli strains, 12 different E. coli serotypes were identified namely, O26:H11 (nežS6), O111:H2 (nežS5), O128:H2 (nežS5), O91:H21 (nežS4), O124 (nežS3), O127:H6 (nežS3), O103:H21 (nežS2), O153 (nežS1), O113:H4 (nežS2), O6 (nežS1), O121:H7 (nežS1) and O146 (n=1). Regarding PCR results, 31(91.19%) E. coli strains harbored STa and seven strains carried hly gene (20.59%) while non E. coli isoates harbord LT gene. Conclusively, raw milk can be considered as serious source of pathogenic E. coli, therefore, proper management practices and effective control measures are recommended to improve milk hygiene and sanitation. Key words: Raw milk, Escherichia coli, enterotoxin genes, haemolysin gene.

Escherichia coli plays a part in maintaining intestinal physiology. Although, there are pathogenic strains that cause different syndromes of diarrheal disease. E. coli strains are the cause of a number of diseases in broiler chickens, leading to death, decrease in production or condemning of carcasses. This study aimed to determine phenotypes and virulence associated genes of avian pathogenic Escherichia coli (APEC) recovered from diseased and freshly dead chickens including, shiga toxin 1, shiga toxin 2 and intimin using genotypic methods. A total of 200 chicken visceral organs (liver, lungs, spleen and heart) collected from diseased and freshly dead birds (four organs per each bird) were subjected for conventional culturing, serotyping and molecular CHARacterization of virulence genes. 32 (16%) of isolates were biochemically identified as E.coli and confirmed by PCR using phoA gene. O78, .O8, O145 and O1 are the most prevalent serotypes from APEC isolates. stx1 and stx2 were determined by multiplex PCR , while eae gene was detected by uniplex PCR . stx2 gene was detected in 50% ( 16/32), while, 81.26% (26/32) of APEC isolates harbored eae. stx1 was not detected in all the tested isolates. The obtained results demonstrated the importance of studies in E. coli of avian origin in regions associated with intensive poultry industry, aiming to evaluating the predominant strains and also acquiring preventive measures to minimize losses due to APEC

Aim This study describes the prevalence of Escherichia coli in frozen chicken meat intended for human consumption with emphasis on their virulence determinants through detection of the virulence genes and recognition of the extended-spectrum β-lactamase (ESBL) encoding genes (blaOXA and blaTEM genes). Materials and methods A total of 120 frozen chicken meat samples were investigated for isolation of E. coli. All isolates were subjected to biochemical and serological tests. Eight serotypes isolated from samples were analyzed for the presence of various virulence genes (stx1, stx2, and eae A genes) using multiplex polymerase chain reaction (PCR) technique. Moreover, the strains were evaluated for the ESBL encoding genes (blaTEM and blaOXA). Results Overall, 11.66% (14/120) chicken meat samples carried E. coli according to cultural and biochemical properties. The most predominant serotypes were O78 and O128: H2 (21.5%, each), followed by O121: H7 and O44: H18. Molecular method detected that 2 strains (25%) harbored stx1, 3 strains (37.5%) stx2, and 3 strains (37.5%) both stx1 and stx2, while 1 (12.5%) strain carried eae A gene. Particularly, only O26 serotype had all tested virulence genes (stx1, stx2, and eae A). The results revealed that all examined 8 serotypes were Shiga toxin-producing E. coli (STEC). The ESBL encoding genes (blaTEM and blaOXA) of STEC were detected in 4 (50%) isolates by multiplex PCR. The overall incidence of blaTEM and blaOXA genes was 3 (37.5%) and 2 (25%) isolates. Conclusion The present study indicates the prevalence of virulent and ESBL-producing E. coli in frozen chicken meat intended for hospitalized human consumption due to poor hygienic measures and irregular use of antibiotics. Therefore, the basic instructions regarding good hygienic measures should be adapted to limit public health hazard.

Aim: This study was designed to isolate and identify yeast species from milk and meat products, and to test their antimicrobial activity against some bacterial species. Materials and Methods: A total of 160 milk and meat products samples were collected from random sellers and super markets in New Damietta city, Damietta, Egypt. Samples were subjected to yeast isolation procedures and tested for its antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. In addition, all yeast species isolates were subjected to polymerase chain reaction (PCR) for detection of khs (kievitone hydratase) and pelA (pectate degrading enzyme) genes. Results: The recovery rate of yeasts from sausage was 20% (2/10) followed by kareish cheese, processed cheese, and butter 10% (1/10) each as well as raw milk 9% (9/100), and fruit yoghurt 30% (6/20). Different yeast species were recovered, namely, Candida kefyr (5 isolates), Saccharomyces cerevisiae (4 isolates), Candida intermedia (3 isolates), Candida tropicalis (2 isolates), Candida lusitaniae (2 isolates), and Candida krusei (1 isolate). khs gene was detected in all S. cerevisiae isolates, however, pelA gene was not detected in all identified yeast species. Antimicrobial activity of recovered yeasts against the selected bacterial species showed high activity with C. intermedia against S. aureus and E. coli, C. kefyr against E. coli, and C. lusitaniae against S. aureus. Moderate activities were obtained with C. tropicalis, C. lusitaniae, and S. cerevisiae against E. coli; meanwhile, all the tested yeasts revealed a very low antimicrobial activity against P. aeruginosa. Conclusion: The obtained results confirmed that some kinds of yeasts have the ability to produce antimicrobial compounds that could inhibit some pathogenic and spoilage bacteria and these antimicrobial activity of yeasts enables them to be one of the novel agents in controlling spoilage of food.

Staphylococcus aureus is one of the most significant pathogens causing bovine mastitis. Among the secreted staphylococcal virulence factors, enterotoxins which can induce food poisoning, toxic shock syndrome (TSS) and bovine mastitis. A total of 140 gram-positive, catalase-positive cocci were considered as an etiological agent of clinical and subclinical bovine mastitis, being tested for sugar and mannitol fermentation, urease production, citrate utilization, egg yolk factor production, haemolytic properties and coagulase production. All 140 strains were identified as Staphylococcus aureus. Staphylococcal Enterotoxin Test - Reverse Passive Latex Agglutination (SET-RPLA) is the most commonly used method for the determination of enterotoxins of S. aureus. It has several advantages at present, including high specificity, simplicity and economy. It was found that six strains produced enterotoxin D, whereas, other strains didn’t produce enterotoxins as detected by the SET-RPLA. The relationship between enterotoxigenicity and coagulase production demonstrated that all enterotoxigenic isolates showed positive reaction for coagulase production, but not all coagulase positive staphylococcal isolates were enterotoxigenic

Little is still known about prevalence of methicillin resistant Staphylococcus aureus (MRSA) in broilers, so this study aimed to determine its prevalence, antibiogram patterns and the site of resistant genes using PCR. About 57 staphylococcal isolates of 78 samples (73%) recovered from broiler chicken were classified into coagulase positive staphylococci (CPS) (40.3%) and coagulase negative staphylococci (CNS) (59.6%). The CPS isolates were identified as MRSA (34.8%) and methicillin sensitive Staphylococcus aureus (MSSA) (65.2%) according to oxacillin resistance by disc diffusion method. The CPS isolates showed the highest rate of resistance to trimethoprim/sulphamethoxazole (100% and 93.3% for MRSA and MSSA respectively), erythromycin (100% and 93.3% for MRSA and MSSA respectively), oxacillin and cefoxitin (100%, 87.5% MRSA and 0%, 6.7% MSSA respectively), ceftriaxone (87.5% and 73.3% for MRSA and MSSA respectively) and amoxicillin (75% and 40% for MRSA and MSSA respectively). Moreover, the CNS showed resistance against trimethoprim/sulphamethoxazole with 85.3%, followed by 79.4% erythromycin, 55.9% ceftriaxone, 47% cefoxitin, 47% amoxicillin, and oxacillin (44%). PCR assay revealed that four (80%) of five MRSA isolates were harbored mecA gene. The screening of mecA, dfrA and ermC resistant genes was done on plasmid and chromosomal DNA of four MRSA isolates. All of them were chromosome linked genes, but none of these resistant genes were detected on plasmid DNA. All examined isolates (100%) contained ermC gene. In addition, the dfrA gene was detected in 2 (50%) out of the 4 isolates.