Keywords : nuc gene

Direct detection of Staphylococcus aureus in camel milk in the Nineveh governorate by using the PCR technique

Omar H. Sheet; Dhyaa M. Jwher; Raad A. Al-Sanjary; Ahmed Dh. Alajami

Iraqi Journal of Veterinary Sciences, 2021, Volume 35, Issue 4, Pages 669-672
DOI: 10.33899/ijvs.2020.127725.1524

Staphylococcus (S.) aureus is the main facultative organism of contagious intramammary infections from lactating animals. It is considered a major foodborne organism that can cause food poisoning conditions around the world. Camels are very important to the lifestyle of many countries because they can produce milk that contains the major components such as proteins, energy, vitamins, and minerals. The present study used a polymerase chain reaction (PCR) method on a base of the nuc gene as a target gene, which is a specific gene that recognizes the S. aureus amongst other microorganisms. Fifty milk samples have been collected from camels from different areas of the Nineveh Governorate, Iraq. According to the phenotypic characteristics, isolation and identification of S. aureus have been accomplished by characterizing the shape of the colonies, painting the suspected isolates by gram stain, using the biochemical tests such as coagulase and catalase. In this study, S. aureus was isolated from 70% (35/50) camel milk samples. The classical method of identifying the S. aureus isolated from camel milk was consistent with the PCR method. The PCR technique indicated that all positive S. aureus possessed the nuc gene. The increased percentage of S. aureus isolated from the camel milk has a relationship with the type of farm management, poor nutrition, and/or environmental conditions, rather than treatment of the infected camel. The PCR method is considered one of the best-used techniques to identify the S. aureus isolated from camel milk by detection of nuc gene, the specific gene of S. aureus.

Detection of methicillin-resistant Staphylococcus aureus from broiler carcasses in Mosul city

Omar H. Sheet; Saba A. Hussein; Aamer Y. Al-Chalaby

Iraqi Journal of Veterinary Sciences, 2021, Volume 35, Issue 3, Pages 489-493
DOI: 10.33899/ijvs.2020.127052.1451

Staphylococcus (S.) aureus is deemed as one of the main pathogens in human and animals. S. aureus can produce various toxins that usually implicated in food poisoning. S. aureus could possess the mecA gene, which is the principle cause of β-lactam antibiotics resistance, particularly methicillin-resistant S. aureus (MRSA). Broiler’s meat is worthy food for humans, but it may expose to contamination with MRSA during the poultry processes in the slaughterhouse. The current study aimed to assessment the spread of S. aureus and MRSA in the broiler carcasses via detection the nuc and mecA gene and their resistance to different antibiotics. Fifty skin swabs were taken from the broilers carcasses, during their processing in poultry slaughterhouses that scattered in various districts in the Nineveh Governorate during the period between January to April 2020. The results showed that S. aureus was recovered in broiler’s skin swabs at a percentage of 66% (33/50) which confirmed by nuc gene, while MRSA isolates constitute 40% (20/50) of all S. aureus isolates, and distinguished as MRSA by their possessing mecA gene. All MRSA isolates were resistant to Ampicillin/Sulbactam, Methicillin, and Ampicillin/Cloxacillin antibiotics. The present study stressed on the reduction as much as any possible source of broiler carcasses contamination with S. aureus including MRSA during and post poultry processing, through applying high levels of hygienic conditions in all poultry processing premises to attain high standards of sustainability and public health standards.

Plasmid transformation and curing of nalidixic acid gene in Staphylococcus aureus isolated from buffaloes mastitis and workerʼs hands

D. A. Khaleel; R. M. Othman; B. Y. Khudaier

Iraqi Journal of Veterinary Sciences, 2018, Volume 32, Issue 2, Pages 167-174
DOI: 10.33899/ijvs.2019.153845

The present study was designed to detect resistant site of nalidixic acid through transformation and plasmid curing of S. aureus strains isolated from buffalo milk with subclinical mastitis and workers’ hands. A total of 37 S. aureus isolates including 17 isolates recovered from buffalo milk infected with subclinical mastitis, in addition to 20 isolates recovered from workers’ hands. All 37 isolates were investigated by detection of the 23S rRNA gene and various other species specific genes including coa, nuc and clfA. The antibiotic resistance of S. aureus isolates was performed by the discs diffusion method using 19 antibiotics. Plasmid transformation method was carried out by transferring the plasmid isolated from S. aureus into competent Escherichia coli HB 101 in order to detection the resistant site of nalidixic acid. Plasmid curing was accomplished by preparing different concentrations of nalidixic acid (100, 150, 200, 250 and 300 µg/ml) and cultured transformed E.coli on LB agar supported with each of the aforementioned concentrations. The molecular results showed that six isolates (five isolates from milk samples and one from workers’ hands) were identified as S. aureus by coa, nuc, and clfA species specific primers. The six S. aureus isolates were found to be resistant to at least 5 antibiotics which included the nalidixic acid. The results of plasmid transformation revealed that E. coli was able to grow on LB agar supported with 100µg/ml, 150 µg/ml, 200 µg/ml and 250 µg/mlof nalidixic acid and failed to grow on 300 µg/ml concentration.