Virulent gene detection and antibiogramic profile of methicillin resistant <I>Staphylococcus aureus</I> isolated from birds of a poultry farm

Abstract

Methicillin-resistant strains of Staphylococcus aureus (MRSA) are gaining global attention, largely due to their potential public health significance. In  the current study, we investigated the prevalence of MRSA in poultry birds from Benson Idahosa University farm. Twenty-five samples each from poultry droppings, cloacae and nostrils were collected aseptically and screened for total heterotrophic and Staphylococcus aureus counts using
standard culture-based methods. Phenotypic identification of MRSA was carried out using mannitol-oxacillin agar, while the presence of virulence genes (mecA, entA, entB, entC, SCCmec (I, II, III) and tsstI) was investigated by polymerase chain reaction using specific primers. Also, the  antibiogramic activities and multi drug-resistant index were investigated against 6 clinically relevant antibiotics (oxacillin (1 μg), vancomycin (30 μg), ceftazidime (30 μg), ceftriaxone (30 μg), amikacin (30 μg) and ofloxacin (5 μg)). The results showed that total heterotrophic  bacterial and S. aureus are prevalent in poultry birds, with mean heterotrophic counts of 243.08 ± 21.01 × 10⁵ cfu, 169.37 ± 25.30 × 10⁵ cfu and 216 ± 15.89× 10⁵ cfu for poultry droppings, cloacae and nostrils respectively and mean S. aureus counts of 176.30 ± 28.85 × 10⁵ cfu for poultry droppings, 16.52 ± 11.92 × 10⁵ cfu for cloacae and 5 2.72 ± 0.41 × 10⁵ cfu for nostrils. Interestingly, 93.33%, 25% and 10.5% of S. aureus isolated from the droppings, cloacae and nostrils respectively were methicillin resistant. The antibiogramic activities showed the majority of isolates to be multi drug-resistant, while only one MRSA (from poultry droppings) had the mecA gene. The presence of these isolates in poultry birds is of a potential public health concern as they may travel through the food chain and efforts should be made by poultry owners to avoid the indiscriminate use of antibiotics.

Keywords: Methicillin-Resistant Staphylococcus aureus; Poultry; Public Health; Virulence Gene