Occurrence of antibiotic resistance and extended–spectrum β-lactamase production among bacterial respiratory pathogens in Ibadan, Nigeria

The increasing incidence of antibiotic resistance in respiratory pathogens constitutes a challenge to their empiric treatment with conventional agents. This study was conducted to investigate the occurrence of antibiotic resistance and extended spectrum β-lactamase production among bacterial respiratory pathogens. Between June and December 2011, sputum samples were collected from 130 patients who presented with lower respiratory tract infections in two hospitals in Ibadan, Nigeria. The sputum samples were analyzed using standard microbiological techniques. Bacterial pathogens recovered were subjected to susceptibility testing. The Gram-negative bacilli isolated were subjected to double disc synergy test to detect ESBL production among them. Out of 130 cases, only 70(53.9%) had an established bacterial etiology. The most prevalent respiratory pathogen in this study was Staphylococcus aureus (40%) while the least prevalent was Proteus mirabilis (8.6%). Staph aureus, K.pneumoniae and E.coli demonstrated high resistant rates towards the 3rd-generation cephalosporins, fluoroquinolones and gentamycin while S.pneumoniae showed high resistance mainly towards the 3rd-generation cephalosporins and co-amoxiclav. Of the 32 Gram-negative bacilli identified as pathogens, only 12(37.5%) were ESBL producers. All the ESBL producers were susceptible to imipenem (100%), amikacin (100%) and cefepime (100%) while only 83.3% were susceptible to meropenem. High rates of resistance recorded in this study location might be due to the selective influence of extensive usage of third-generation cephalosporins, fluoroquinolones and other antibiotics. Judicious use of these antimicrobial agents, bacteriological diagnosis, epidemiological studies and antibiotic resistance surveillance are essential to control the emergence of the multidrug resistant bacteria.