Al-Qadisiyah Journal of Veterinary Medicine Sciences

Methicillin resistant Staphylococcus aureus (MRSA) is associated with a significant rate of skin and other systemic infections throughout the world in both human and animals. This study was conducted to evaluate the in vitro and in vivo antibacterial activity of commercial coconut oil against MRSA. Clinical isolates of MRSA were obtained from AL- sadder Teaching hospital /Basra / Iraq and were identified and confirmed by standard methods. The in vitro antibacterial activity of coconut oil was studied by disc diffusion method which has showed strong suppressive activity on MRSA. Full strength coconut oil exhibited better zone of inhibition around MRSA in comparison to diluted preparations. For in vivo activity, 24 adult rabbits were allocated to test MRSA induced skin infection. Four sets of experimental animals each consisting of 6 rabbits were grouped. Multiple regions in each animal in all groups were inoculated with 0.1 ml of MSRA at a concentration of 1.5 x108 cfu/ml. Groups 1, 2, and 3 were additionally treated through injection in the areas of bacterial inoculation with coconut oil, vancomycin antibiotic, and normal saline respectively. Group 4 was left without any additional treatment. Viable bacterial count in the tested skin was measured at two occasions in all animals (24 and 48 hours from the experimental period). Compared to the first 24 hours, the results after 48 hours showed a significant reduction in the viable bacterial count following coconut and vancomycin treatment in comparison to those rabbits treated with normal saline or not treated at all (P-value < 0.05).Coconut oil treatment produced 112 folds reduction in the viable bacterial count with mild visible skin reaction which was comparable to the effect of vancomycin.The current study concluded that the in vivo and in vitro results show that concentrated coconut oil is active against MRSA, making it a possible alternative to some of antimicrobial agents to which these bacteria are resistant.

This study aimed to compare the efficiency of conventional microbiological , Miniaturize kit GP24 and molecular technique by using PCR of nuc gene in identification of S. aureus. Also to evaluate efficiency of the tube coagulase and DNase activity tests. 104 of suspected S. aureus were isolated from different cattle samples, (68.3%) and (75%) were positive for coagulase and DNase tests, respectively. The sensitivity and specificity of coagulase and DNase were 92.5%, 75.7% and 79.1% , 32.4% respectively. The identification rate of S. aureus by GP24 kit and PCR detection using nuc gene were 68.26% and 64.42% respectively. Out of 104(31.7%) of isolates were identified as coagulase negative staphylococci by using GP24 kit. Antimicrobials susceptibility assays of 67 S. aureus isolates revealed that, the highest resistance rates were against penicillin (97%) fallowed by tetracycline (25.4%). While all isolates were found to be highly sensitive toward Imipenem, vancomycin and chloramphenicol (100%) for each. In conclusion the coagulase and conventional microbiological techniques have more reliable results in comparison with DNase test for identification of S. aureus. On other hand, the results of GP24 kit and coagulase tube test were similar in sensitivity and specificity.

Bacteriophages, recovered from sewage samples target E. coli O157:H7, were tested for their biokinetic and morphological characteristics. Bacterial lysis profile of isolated phages was performed using Escherichia coli O157:H7 (NCTC) 12900 as host bacterial cell. Morphological characteristics of phages was visualized by transmission electron microscopy. Multiplicity of infection (MOI) and biokinetic properties, particularly adsorption rate, rise period, latent period, and burst size were also calculated. Electron microscopy revealed that the isolated phages P1and P3 belongs to Siphoviridae family while the P4 phage belongs to Myoviridae; similar to other E. coli O157:H7-specific phages previously isolated. MOI of P1 was 0.01, while P3 and P4 was 0.1 phage/bacterium. These typical MOI yielding the higher titer of phage were used in next phage tests. The adsorption curve of P1 phage were reached to 100% adsorption rate after 25 min of host exposure . Whereas P3 and P4 were taken 35 and 30 minutes, respectively to achieve the same adsorption rate. An implication of this is used in efficient biocontrol strategies for elimination of this bacterial pathogen from their reservoirs (cattle) as well as in the food industry.