Resistance to a last-resort antibiotic is rising sharply in Africa to two multidrug-resistant (MDR) bacterial pathogens that pose major threats in health care settings, according to a study this week in JAC-Antimicrobial Resistance.

In a systematic review and meta-analysis, researchers from Ethiopia examined 35 studies on reported colistin resistance in clinical specimens of Acinetobacter baumannii and Pseudomonas aeruginosa from Africa. A baumannii and P aeruginosa are already resistant to multiple antibiotic classes and are considered critical- and high-priority pathogens by the World Health Organization. Limited treatment options for MDR A baumannii and P aeruginosa in Africa have led to renewed use of colistin, which had been limited to veterinary use because of its toxicity in humans.

While the emergence of colistin resistance in the two pathogens is being reported “with increasing frequency,” the study authors note, “a comprehensive study that analyses and synthesizes the available evidence on the prevalence of colistin resistance in A. baumannii and P. aeruginosa isolates in Africa is still lacking.”

Major clinical consequences

Of the included studies, 20 investigated A baumannii, 10 assessed P aeruginosa, and five evaluated both organisms. The pooled prevalence of colistin resistance in A baumannii was 13.75%, with variation among countries, ranging from 18.26% in Egypt to 10.89% in South Africa. For P aeruginosa, the pooled prevalence of colistin resistance after adjustments was 14.42%, ranging from 13.55% in Egypt to 1.07% in Ethiopia.

Resistance rose dramatically over time, from 5.64% to 16.45% in A baumannii and from 2.26% to 30.54% in P aeruginosa between 2010–2017 and 2018–2023.

The authors say the increasing prevalence of colistin resistance in Africa has serious implications for antimicrobial therapy strategies and major clinical consequences.

“This threatens the role of colistin as a last-resort therapy and is associated with higher morbidity, mortality and healthcare costs,” the authors wrote. “Urgent action is therefore needed to strengthen antimicrobial stewardship, implement standardized resistance surveillance and reinforce infection prevention and control measures across the region.”

The University of Southern Denmark has placed a “full hold” on a heavily criticized clinical trial of the hepatitis B vaccine in Guinea-Bissau owing to ethical concerns. The move comes after officials in Guinea-Bissau announced last month that the trial—which would provide life-saving hepatitis B vaccines at birth to only half of the 14,000 infants in the study—has been stopped.

The US Centers for Disease Control and Prevention (CDC) awarded $1.6 million to researchers from the Danish university’s Bandim Research Project for the study, which has been condemned as biased and unethical by public health experts around the globe, the World Health Organization (WHO), and members of Congress.

CIDRAP News broke the news of the study in December, shortly after the single-blinded clinical trial was announced in the Federal Register. 

Seeking WHO review

Ole Skøtt, MD, DMSc,dean and professor of the faculty of health sciences at the university, said he contacted the WHO’s research ethics review committee to ask to review study the protocol. 

“There may be issues relating to conflicts of interest in relation to the approval granted by the local ethics committee in Guinea-Bissau for the hepatitis B project,” Skøtt told CIDRAP News. “It is important to us that the research ethics issues are thoroughly examined before any decision is made on the further course of action.”

Spokespeople for the WHO and the Department of Health and Human Services, which includes the CDC, did not respond before this article went to press.

The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) reported avian flu detections in Pennsylvania, Maryland, Michigan, and Indiana this past week, and it said 15.2 million birds have been affected by outbreaks in the past 30 days.

In Lancaster County, Pennsylvania, a commercial table egg-layer farm had an outbreak among 870,000 birds. Cecil County, Maryland, also reported an outbreak of 354,100 among table egg pullets.

Similar to last week, a commercial turkey farm in Kent County, Michigan, was struck, affecting 51,700 birds. And Elkhart County, Indiana was once again hit, with 7,600 birds at a commercial duck meat facility affected.

APHIS also noted an outbreak in Portage County, Ohio, in a backyard flock.

Wild-bird detections in the Bronx

In the past 30 days, APHIS has confirmed 86 infected flocks, including 48 commercial and 38 backyard flocks.

Wild-bird avian flu detections continue across the country, but like the previous week, detections have slowed down. Only 25 wild birds were confirmed to have highly pathogenic avian flu, including several Canada geese in the Bronx, New York.

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