A surge in the development and spread of antibiotic resistance has become a major cause for concern. Over the past few decades, no major new types of antibiotics have been produced and almost all known antibiotics are increasingly losing their activity against pathogenic microorganisms. The levels of multi-drug resistant bacteria have also increased. It is known that worldwide, more than 60% of all antibiotics that are produced find their use in animal production for both therapeutic and non-therapeutic purposes. The use of antimicrobial agents in animal husbandry has been linked to the development and spread of resistant bacteria. Poultry products are among the highest consumed products worldwide but a lot of essential antibiotics are employed during poultry production in several countries; threatening the safety of such products (through antimicrobial residues) and the increased possibility of development and spread of microbial resistance in poultry settings. This chapter documents some of the studies on antibiotic usage in poultry farming; with specific focus on some selected bacterial species, their economic importance to poultry farming and reports of resistances of isolated species from poultry settings (farms and poultry products) to essential antibiotics.

Background: Antibiotic resistance in bacteria has long been recognized as a major health problem occurring worldwide. The emergence of methicillin-resistant Staphylococcus aureus (MRSA) remains a global health problem. MRSA is reported as one of the leading pathogens involved in increased rates of morbidity and mortality amongst patients in Ghana. This study determined the prevalence and resistance mechanisms of MRSA isolated from patients in selected hospitals in the Ashanti Region of Ghana. Antibiograms of the isolates were determined using the Kirby-Bauer disk diffusion method. Antibiotic resistance genes (mecA and mecC) were detected and efflux pump activity assessed using polymerase chain reaction (PCR) and microbroth dilution methods, respectively. Results: Out of 626 samples obtained from patients, S. aureus was identified in 68, representing 10.9%. Multidrug resistance (MDR) was observed in 46 (67.6%) of the S. aureus isolates of which 28 (60.9%) were Methicillin Resistant Staphylococcus aureus (MRSA). The MRSA isolates showed higher susceptibility to trimethoprim-sulfamethoxazole (50%) and higher resistance to oxacillin and cefoxitin (100%). mecA gene was identified in 9 (32.1%) of the MRSA isolates whereas mecC gene was absent in all the isolates. The isolates did not exhibit any multiple efflux pump activities. Conclusion: The prevalence of MDR-MRSA in S. aureus infections at healthcare facilities in the Ashanti region was found to be high. The presence of the mecA gene was identified as a possible mechanism responsible for resistance in the MRSA isolates.