The occurrence of tetracycline resistance determinants in 203 Escherichia coli isolates recovered from clinical samples at three different hospitals in Nigeria between June 2009 and May 2010 was investigated. The isolates were subjected to standard procedures. Antibiotic susceptibility to a panel of eight antibiotics was also performed, and resistance genes were detected with the polymerase chain reaction (PCR) technique. One hundred and six E. coli isolates (52.2%) were obtained at LAUTECH Teaching Hospital Osogbo, 85 (41.9%) from OAUTHC Ile Ife and 12 (5.9%) from Osun State Hospital Asubiaro Osogbo. Result of the disk diffusion antibiotic susceptibility test showed 96.1% isolates to be resistant to ampicillin, 77.8% to tetracycline, 37.9% to cotrimoxazole, 38.4% to nalidixic acid, 20.7% to ofloxacin, 17.7% to ceftriaxone, 11.8% to gentamycin, and 2% to nitrofurantoin. One hundred and sixty two (79.9%) isolates had minimum inhibitory concentration (MIC) of tetracycline ≥ 128 μg/ml. The polymerase chain reaction (PCR) detected tetA gene in 89 (43.8%) isolates, tetB gene in 65 (32.0%), and both tetA and tetB genes in 9 (4.4%) isolates. The study demonstrated a relatively high level of gene mediated antibiotic resistance to tetracycline and other antibiotics in E. coli clinical isolates in Southwest region of Nigeria.
Authors:G. Odewale, O. J. Adefioye, J. Ojo, F. A. Adewumi, and O. A. Olowe
Acinetobacter baumannii is a ubiquitous pathogen that has emerged as a major cause of healthcare-associated infections at Ladoke Akintola University Teaching Hospital. Isolates were assayed according to standard protocol. The isolates were subjected to molecular techniques to detect blaOXA, blaTEM, blaCTX-M, and blaSHV genes in strains of the A. baumannii isolates.
The prevalence of A. baumannii was 8.5% and was most prevalent among patients in the age group 51–60 (36%); the male patients (63.6%) were more infected than their female counterparts. Patients (72.7%) in the intensive care unit (ICU) were most infected with this organism. The isolates showed 100% resistance to both amikacin and ciprofloxacin and 90.9% to both ceftriaxone and ceftazidime, while resistance to the other antibiotics used in this study were: piperacillin (81.8%), imipenem (72.7%), gentamycin (72.2%), and meropenem (63.6%). None of the isolates was, however, resistant to colistin. PCR results showed that blaOXA, blaTEM, and blaCTX-M genes were positive in some isolates, while blaSHV was not detected in any of the isolates.
This study has revealed that the strains of A. baumannii isolated are multiple drug resistant. Regular monitoring, judicious prescription, and early detection of resistance to these antibiotics are, therefore, necessary to check further dissemination of the organism.