Staphylococcus aureus, ‘one of the most adaptable and virulent pathogens in modern times’ is a facultative anaerobic Gram-positive coccal bacterium able to infect any tissue of the human body to cause ailments ranging from minor skin infections to life-threatening diseases. The bacterium is also known to colonize and infect both pets and livestock, including dogs, cats, rabbits, horses, cattle and pigs to result in zoonosis. A major concern is the prevalence of irrepressible multidrug resistant S. aureus in pets and livestock, as these may serve as reservoirs for human colonization and compound the problem of emergence and/or re-emergence of global diseases. This project was designed to assess the prevalence of multidrug resistant livestock associated S. aureus isolated from nasal passage of healthy cattle in Kara Market, Ogun state, Nigeria.
A total of 500 nasal samples were collected from healthy adult cattle (250 from male and 250 from female cattle) but 409 S. aureus isolates were identified(218 from male and 191 from female cattle) by Gram staining and specific biochemical tests.
The antibiogram of the S. aureus isolates revealed that all the isolates exhibited multidrugresistance (8/12) to ceftriaxone, gentamicin, cotrimoxazole, erythromycin, amoxicillin, streptomycin, chloramphenicol and ampicillin, fairly resistant(3/12) to quinolones but weakly resistant (1/12) to vancomycin. High minimum inhibitory concentration greater than 128 μg/ml was exhibited by 63.3% of the isolates against flucloxacillin (methicillin) but 28% of the isolates were equally resistant (>128 μg/ml) to vancomycin (glycosidic). The in-vitro combination effect of flucloxacillin and ampicillin on the isolates resulted in 86.3% additive to imply the unsuitability of the combination to effectively control staphylococcal infections.
Vancomycin was observed to be bactericidal to livestock associated multidrug and/or methicillin resistant S. aureus in this study. The quinolones antibiotics (ciprofloxacin, pefloxacin and ofloxacin) are fairly effective (known to be relatively non-toxic) may be used to complement and/or substitute toxic antibiotics in curtailing ailment resulting from multidrug resistant S. aureus.
Keywords: S. aureus, Antibiotics, Cattle, Resistance, Multidrug.
1.1 Background to the Study
Cattle are large bodied ruminants that feed on pastures and forages or fodder. In Nigeria, cattle are reared primarily for meat which is a veritable source of protein for humans, and for milk (Arowolo et al., 2013). Cattle rearing in Nigeria is an old occupation which is traditionally practiced by Fulanis and Shuwa Arabs in northern Nigeria with an extremely few local villages in the southern Nigeria (Erebor, 2003).
Staphylococcus aureus is a facultative anaerobic gram-positive coccal bacterium and due to a combination of numerous bacteria immune-evasive strategies which it uses, it is considered a successful pathogen. The nasal passages is considered to be the major habitat (Kluytmans et al., 1997; Lowy, 1998; Lowy, 2003) and the biggest supply of S. aureus in people, yet numerous body locales can harbor this bacterium (Vandenbergh & Verbrugh, 1999). S. aureus is a typical tenant of the skin (Lowy, 2003; Williams, 1963), perineum and can likewise be found in the axillae (Ridley, 1959), vagina (Guinan et al., 1982) and the gastrointestinal tract (Williams, 1963). S. aureus strains are noteworthy human pathogens and are conceivably ready in contaminating any human body tissue, bringing on everything from skin contaminations to life-debilitating sicknesses. In people, the diseases brought on by S. aureus can be partitioned into these three sorts in general; shallow sores, (for example, surgical site and wound contaminations), life and systemic undermining factors, (for example, osteomyelitis, endocarditis, pneumonia, mind abscesses/wounds, bacteraemia and meningitis), then toxinoses, (for example, poisonous stun disorder, sustenance harming and singed skin disorder (Alo et al., 2013; Aires de Sousa et al., 2004; Lowy, 2003). The sign of staphylococcal contamination are the boils that contain discharge which is made up of dead neutrophils, dead and living microbes, tissue (necrotic), the lysed host substance and bacterial cells. The immunocompetent hosts, as a rule, effectively clear the disease and deplete the ulcer, though for the immunocompromised and sporadically for a sound individual, the contamination might advance to a more profound tissues and turn into a conceivably lethal intrusive contamination (Norvick, 2006). It is still one of the five most common causes of nososcomial infections, often causing postsurgical wound infections (Bowersox, 1999). S. aureus is likewise known to colonize and contaminate both pets and animals, including pooches, felines, rabbits, stallions, steers and pigs (Morgan, 2008). A noteworthy concern is the nearness of methicillin safe S. aureus (MRSA) in pets and domesticated animals, as these may fill in as repositories for human colonization, an illustration is MRSA ST398 from pigs (Weese, 2010).
The unnecessary utilization of antibiotics has prompted to the rise of different medication safe strains of S.aureus (Lowy, 1998). The Penicillin was presented for curing infections caused by S. aureus in the 1940s, and adequately diminished mortality and bleakness. Be that as it may, in late 1940s, its resistance because of the nearness of penicillinase developed (Eickhoff, 1972). The staphylococci are extremely fit for advancing imperviousness to the regularly utilized antimicrobials, for example, erythromycin (Walmark & Finland, 1961), ampicillin (Klein and Finland, 1963), and antibiotic medication (Eickhoff, 1972). Much of the time, imperviousness to antimicrobial agents is coded for by qualities carried on plasmids, representing the quick spread of resistant microscopic organisms (Morris et al., 1998). One purpose behind the proceeding with essential part of S. aureus in illness is its inclination and propensity to wind up distinctly impervious to antimicrobial (Waldvogel, 2000). S. aureus is presently the main general reason for nosocomial diseases and, as more patients are dealt with outside the healing center setting, is an expanding worry in the group (CDC NNIS System, 2001; Diekema, 2001).