Sensitivity to commercial teat dips (nonoxinol-9 iodine complex and chlorhexidine digluconate) of 56 Staphylococcus (S.) aureus strains isolated from quarter milk samples of various German dairy herds treated with different teat dipping schemes was investigated in this study. The minimum inhibitory concentration was determined using a broth macrodilution method according to the German Veterinary Association guidelines. The main objective of the current study was to induce in vitro resistance induction of S. aureus to chemical disinfectants. Ten different strains were repeatedly passed ten times in growth media with sub-lethal concentrations of disinfectants. Nine strains showed a significant reduction in susceptibility to the nonoxinol-9 iodine complex but only one strain developed resistance to chlorhexidine digluconate. Stability of the acquired resistance was observed in all S. aureus strains adapted to the nonoxinol-9 iodine complex and chlorhexidine digluconate. In contrast, simultaneous resistance to different antibiotics was not observed in any of the ten investigated S. aureus strains. However, the isolates exhibited a high degree of resistance to penicillin G. Based on these results, resistance of S. aureus to chemical disinfectants may be more likely to develop if the chemicals are used at concentrations lower than that required for an optimal biocidal effect.

This study was implemented to assess the mechanism by which Moringa oleifera leaf extract (MOLE) improves the quality and prolongs shelf-life of the broilers’ breast meat. Ninety Cobb chicks were randomly allocated to 3 groups. A control group received the standard diet, whereas the other two groups received diets containing MOLE at the doses of 250 and 500 mg/kg for 21 days. Inclusion of MOLE in broilers diet significantly reduced the detrimental changes in the overall sensory attribute scores, characteristic color and odor, and the loss of breast muscle elasticity during storage. Furthermore, it significantly reduced concentrations of thiobarbituric acid, total volatile nitrogen, non-esterified fatty acids, and peroxide, during storage compared to the control samples. No effect on the concentrations of heavy metals, such as copper, cadmium, and lead, was observed. Decomposition of samples was delayed as indicated by lower pH values and higher sensory scores at 4 and 6 days of storage in the MOLE groups. Reduced contamination with E. coli and Salmonella species indicated an antibacterial effect of MOLE. Finally, the present study highlights that MOLE supplementation may play a role in improving quality and shelf-life of the chilled breast meat in broilers.

Mastitis is one of the most economic disease affecting dairy cows worldwide. Identification of mastitis pathogens still depends principally on culture and phenotypical method, which is a difficult and timeconsuming. Newly, microbiologists have focused their attention on the use of Mass Spectrometry (MS) for microbial identification, especially Matrix Assisted Laser Desorption Ionization Time-Of-Flight (MALDI-TOF). Therefore, this study was designated to evaluate the ability of MALDI-TOF to identify some contagious mastitis pathogens comparing with phenotypical methods such as API panels and VITEK 2 system. A total of one hundred twenty of Staphylococcus aureus (S. aureus), Coagulase Negative Staphylococci (CNS) and Streptococcus agalactiae (Strept. agalactiae) strains isolated from milk of cows affected by clinical and subclinical mastitis were used in the study. According to the results, ~95% of S. aureus, 100% of CNS and Strept. agalactiae were correctly identified by MALDI TOF MS. All S. aureus isolates were then confirmed by a nuc-based PCR technique. While ~92% of S. aureus, 87% of Strept. agalactiae and 76% of CNS were identified by VITEK 2 system. Moreover, ~89% of S. aureus, 80% of Strept. agalactiae and 72% of CNS were identified by API system. In brief, the results demonstrated that MALDI-TOF is a fast and truthful technique which has the capability to replace conventional identification of several bacterial strains usually isolated in clinical laboratories of microbiology. Therefore, it is recomended that MALDI-TOF MS technology can be regularly used in veterinary laboratories for identification of different species of bacteria, particularly when failure of phenotypic methods forces clinical microbiologists.

This study was performed to identify various bacteria from feces of calves suffering from diarrhea, and to determine in vitro antimicrobial activity of silver, gold and copper nanoparticles against the antibiotic-resistant bacteria isolated from fecal samples. Fecal samples were collected from 153 diarrheic calves and primarily tested for the presence of Escherichia coli, Salmonella spp. and Staphylococcus aureus using bacteriological examination, biochemical reactions and polymerase chain reaction. The minimum inhibitory concentrations of silver, gold and copper nanoparticles against identified bacterial isolates were determined by a broth dilution method. 84 bacterial isolates from the 153 fecal samples were identified using bacteriological, biochemical and genotypical methods. Escherichia coli was considered the most frequent bacterium isolated numbering 31 (36.90%) followed by Salmonella sp. as the second most prevalent 16 (19.04%). Further isolates such as Staphylococcus aureus 10 (11.90%) were isolated and identified. The MIC values of silver, gold and copper nanoparticles with a size of 10 nanometers (nm) against the three types of bacteria were ranged from 0.625 to 10 μg/ml, 2.5 to 20 μg/ml and 2.5 to 20 μg/ml, respectively. While these values with a size of 20 nm were 0.312 to 2.5 μg/ml, 1.25 to 10 μg/ml and 2.5 to 10 μg/ml, respectively. Additionally, the mean time of the antimicrobial action of silver, gold and copper nanoparticles at concentration 10 nm against all isolates was 5 min, 30 min and 15 min, respectively. Using of these nanoparticles in a concentration of 20 nm, the mean time was 1, 15 and 5 min, respectively. These in vitro results clearly indicate that the silver, gold and copper nanoparticles might have a superior activity and rapid onset of action against the Gram negative bacteria E. coli and Salmonella spp. and the Gram positive bacteria Staphylococcus aureus with diarrheal origin.

Bovine tuberculosis is a chronic bacterial and major infectious disease of cattle and buffaloes caused by Mycobacterium bovis. Rapid diagnosis of bovine tuberculosis is considered one of the cornerstones for worldwide control as it permits early epidemiological and therapeutic interventions. Therefore, this study was designed to evaluate conventional techniques (tuberculin test, Ziehl Neelsen staining and culturing) in comparison with proven molecular laboratory techniques (LCD array and IS6110 PCR) for identification of Bovine tuberculosis. A total of 902 Egyptian animals (480 buffaloes and 422 cattle) were examined by tuberculin test, and the positive reactors were slaughtered. Tissue samples were collected for staining as well as culturing. Moreover, LCD array and PCR using IS6110 on DNA extracted from tissue and culture samples were carried out for molecular identification of M. bovis. According to the results, the tuberculin positive cases for cattle and buffaloes were 2.14% (9 cases) and 5.62% (27 cases), respectively. After post-mortem examination, the prevalence of tuberculin positive cases with visible lesions was 88.9% for cattle and 14.8% for buffaloes. Alternatively, these percentages were 11.1% and 85.2% for cattle and buffalo carcasses with non-visible lesions. The percentage of cattle and buffaloes showing positive culture was 88.9% and 62.9%, respectively. This percentage was 69.5% after staining with Ziehl Neelsen. In contrast, LCD array and IS6110 were 100%, confirming the isolation results. In conclusion, LCD array depending on 16S RNA and DNA hybridization with specific probes for detection of M. bovis are rapid, sensitive and labor-saving when combined with IS6110-PCR.