Antimicrobial resistance — the ability of microorganisms to resist drugs that have been developed to control them — is a severe problem in African countries. The continent has the highest global burden of antimicrobial-resistant infections, with 114.8 deaths per 100,000 people.
One of the causes of resistance is inappropriate use of antibiotics. Using the wrong antibiotic to treat an infection enables resistant bacteria to flourish and spread.
“It’s essential to identify the type of infection present so that the right antimicrobial agent can be selected,” said Fred Tenover, distinguished research professor of microbiology at the University of Dayton. “Treatment guidelines stress the importance of using laboratory data to guide treatment. Physicians need laboratory data to choose the right antibiotic, at the right dose, for the right period of time. This is known as antimicrobial stewardship.”
But in low- and middle-income countries, hospital budgets don’t include much funding for laboratories, limiting available data to create local treatment guidelines. Treatment choices become “empiric” — the doctor’s best guess based on the patient’s signs and symptoms and the doctor’s experience. This can lead to choosing ineffective antibiotics, which can lead to increases in resistant bacteria.
Tenover and Nubwa Medugu, a clinical microbiologist at Nile University of Nigeria, have noted how the lack of laboratory data hinders the effective treatment of patients with infections. They also observed that the cost of producing quality laboratory data is high and rising.
One way forward is to pool laboratory data from other hospitals to develop a list of what bacteria are prevalent in the region and which drugs work against them. To accomplish this, Tenover and Medugu studied multidrug-resistant bacteria obtained from patients in six hospitals in northern Nigeria with a goal of determining which antimicrobial agents might still be effective therapies in this region.
Data from their study focused on the resistance patterns of multidrug-resistant infections support the value of regional guidelines. The results also point to strategies of antimicrobial stewardship that might work specifically in Nigeria. Such strategies could include judicious use of two novel antimicrobial agents, tigecycline or fosfomycin, which currently are not commonly used in Africa, for serious infections when guided by laboratory data.
The study went beyond the use of routine testing methods and included whole genome sequencing of the resistant bacteria. This was done to understand what made these organisms so resistant to antibiotics at the molecular level.
“The data revealed an astonishingly high number of genetic mechanisms making the microorganisms resistant,” said Tenover. “This shows that the choice of agents to treat infections has not been optimal in the past.”
Additionally, among the isolates studied, several belonged to newly emerging “high-risk” bacterial clones. These are bacterial species of high virulence that are easily spread among patient populations. Therefore, especially in Africa, hospitals need to pay closer attention to infections caused by resistant bacteria to ensure infections do not spread to other patients.
Some of the resistance genes were capable of moving from one microorganism to another (mobile resistance genes). Other genes were embedded within the bacterial chromosome. Unlike the mobile genes, which can be unstable and lost, the ones in the chromosome are often stable. “This mix of mobile and embedded resistance genes suggests that resistance will not go away any time soon,” said Tenover.
However, there is hope for decreasing the impact of resistance through effective antibiotic prescribing. Antimicrobial stewardship based on laboratory data is effective especially if done locally, regionally and nationally.
Tenover and Medugu note this problem is a global issue; similar multidrug-resistant strains of bacteria have been detected in the United States, Europe, Asia and Australia. The good news is that the pair identified antibiotics that are still effective even against the most resistant bacterial strains they studied. In addition, there are efforts in place to limit the spread of resistant microorganisms.
“There are things that everyone can do to help bring antibiotic resistance under control,” said Tenover. “For example, the U.S. Centers for Disease Control and Prevention list five things that everyone should know about drug resistance and 10 activities to protect yourself and your family against resistance. This is a global battle that we need to win.”
This article is adapted from a piece that originally appeared in The Conversation