High antimicrobial resistance among bacterial isolates of blood stream infections (BSI) in a Nigerian University Teaching Hospital

Prevalence of tet genes mediating tetracycline resistance in Escherichia coli clinical isolates in Osun State, Nigeria

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.

Antibiotic-resistant bugs in the 21st century: A public health challenge

Antimicrobial resistance, which has been reported against almost every antibiotic discovered, is one of the most urgent public health problems, threatening to undermine the effectiveness of infectious disease treatment worldwide. Since penicillin ushered in the antibiotic era in the mid 20th century, the scientific world had engaged in a war between the development of antibacterial agents and bacterial resistance. During the first decade of the 21st century, grave concern has been expressed over the evolution of multi-drug resistant staphylococci, enterococci, and mycobacteria, which pose serious clinical and public health challenge to humans. The present picture is frighteningly similar to the pre-antibiotic era, with reports of nosocomial spread and intercontinental dissemination of multi-drug resistant bacteria. For infected patients, there is no magic bullet. The microbial pathogens appear to be gaining the upper hand, coupled with a recent dramatic reduction in antibiotic research by pharmaceutical companies because of the high cost of drug research. Several compounds that have recently been developed or resurrected to treat gram-positive infections are still unable to meet the armamentarium of resistance mechanisms of these pathogens. The situation is worse for gram-negative organisms, where no new drug is currently being developed against them. A multi-disciplinary approach to combat resistance is required, which must be applied, sustained, and continuously refined. The key components for maintaining effective antimicrobial chemotherapy will include better use of existing agents, coupled with continuous investment in new and innovative technologies, which must include diagnostics and vaccines in addition to new antimicrobial agents.