Further lab results on samples from patients sickened in an unexplained illness outbreak in a remote part of the Democratic Republic of the Congo (DRC) suggest a severe form of malaria, Reuters reported today, citing a statement from the health ministry.

Officials also said malnutrition was one of the factors in the illnesses, and that the current case total is 592 with a case-fatality rate of 6.2%.

The outbreak in Kwango province’s Panzi health district began in late October, and DRC health officials first learned of the outbreak in early December. Symptoms included fever, headache, cough, breathing problems, and weakness.

Difficult road conditions amid the rainy season have made it hard for investigators to access the area, which has poor communication and little lab testing capacity. Initial samples suggested malaria. Some of the first samples that reached the National Institute for Biomedical Research (INRB) in Kinshasa were of poor quality, and more samples, including respiratory specimens, were collected and sent to the lab. More complete results were expected this week.

A multicenter comparative effectiveness study found that treatment with ceftolozane-tazobactam resulted in higher rates of clinical success than ceftazidime-avibactam for invasive infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa, researchers reported yesterday in The Lancet Infectious Diseases.

The study, conducted at 28 US hospitals from 2016 through 2023, compared outcomes in 420 adult patients with microbiologically confirmed MDR P aeruginosa pneumonia or bacteremia who were treated with ceftolozane-tazobactam or ceftazidime-avibactam for more than 48 hours and matched 1:1 by study site, severity of illness, time to treatment initiation, and infection type. Although both drugs are considered first-line therapies for MDR P aeruginosa infections and have been shown to be more effective than older agents, they have not been compared in real-world observational studies. 

The primary outcome was clinical success at day 30, which was defined as survival, resolution of signs and symptoms of infection with the intended treatment course, and the absence of recurrent infection due to P aeruginosa. Secondary outcomes included all-cause mortality and development of resistance to study drug.

Higher clinical success in pneumonia patients

Clinical success was observed in 168 (61%) of 210 patients treated with ceftolozane-tazobactam and 109 (52%) of 210 patients treated with ceftazidime-avibactam, and the adjusted odds ratio [aOR] of success after treatment with ceftolozane-tazobactam compared with ceftazidime-avibactam was 2.07 (95% confidence interval [CI], 1.16 to 3.70). The results were exclusively driven by higher clinical success in patients with pneumonia (aOR, 2.34; 95% CI, 1.22 to 4.47), as no difference was seen in clinical success rates among patients with bacteremia.

There were no significant differences between groups in 30-day or 90-day mortality. Among patients whose baseline isolates were tested for susceptibility, resistance developed in 22% of patients treated with ceftolozane–tazobactam and 23% of patients treated with ceftazidime–avibactam.

"The totality of the evidence supports preferential use of ceftolozane–tazobactam for the treatment of multidrug-resistant P aeruginosa pneumonia; however, rates of 30-day and 90-day mortality and resistance development are concerning," the study authors wrote. "Future studies are needed to identify adjunctive or alternative treatment strategies that result in further improvements in the outcomes of patients with multidrug-resistant P aeruginosa pneumonia or bacteraemia."

A low-intensity behavioral intervention at Veterans Affairs (VA) outpatient clinics positively influenced the prescribing behavior of primary care providers (PCPs), researchers reported yesterday in Open Forum Infectious Diseases.

In a cluster randomized controlled trial, a team led by researchers with the VA Northeast Ohio Healthcare System compared the proportion of primary care visits with an antibiotic prescription at six VA community-based outpatient clinics assigned to the intervention group and six to a control group. At the intervention clinics, PCPs received quarterly antibiotic use reports with feedback about antibiotics for acute respiratory infections and adverse event letters alerting them about Clostridioides difficile infections and antibiotic-resistant gram-negative bacteria in their patients. 

Antibiotic prescribing was compared in the pre-intervention (4/2020 – 9/2020), intervention (10/2020 – 9/2021), and post-intervention periods (9/2021–9/2022).

Control clinics prescribed more antibiotics

Among 52 PCPs at the six clinics in the intervention group, 66% and 54% received more than one antibiotic use report and adverse event letter. In the intervention clinics, the proportion of primary care visits with an antibiotic prescription during the pre-intervention, intervention, and post-intervention periods was 1.4%, 1.4%, and 1.3%. In the control clinics, prescribing increased from 1.8% pre-intervention to 2.1% and 2.1% during the intervention and post-intervention periods. 

The rate of visits with an antibiotic prescription was not statistically different between the intervention and control clinics in the pre-intervention period (odds ratio [OR], 1.10; 95% confidence interval [CI], 0.87 to 1.39). But clinics in the control arm prescribed more antibiotics during the intervention (OR, 1.30; 95% CI, 1.04 to 1.62) and post-intervention periods (OR, 1.38; 95% CI, 1.09 to 1.74). There were no differences in emergency visits and hospitalizations between the two arms, indicating no unintended negative consequences from the intervention.

The study authors say the findings indicate that a relatively low-intensity intervention can support antimicrobial stewardship in outpatient settings.

"Wider implementation in a post-pandemic setting may enhance antibiotic stewardship and help decrease antibiotic-resistant organisms, benefiting public health," they wrote.

According to media reports, Germany has four new clade 1b mpox cases, including two cases in school-aged children. 

According to a post from the infectious disease blog Avian Flu Diary, the cases are in a family that recently traveled to Africa. One person likely had close contact with a case-patient while traveling, and then spread the virus to three family members. The family lives in the Rheinisch-Bergischer district, near Cologne. 

Health officials from the district are working with the Robert Koch Institute to contact the schools and places of employment of the family and monitor contacts for symptoms. 

Seven nations outside of Africa affected

Clade 1b began spreading last year in the Democratic Republic of the Congo and has since been found in dozens of African countries as well as in Sweden, Thailand, India, the United States, the United Kingdom, and Canada. 

Germany had reported one other clade 1b case in October, and the patient recovered fully. 

This strain of mpox is considered more virulent and transmissible than the clade 2 strain that caused a global outbreak of the virus primarily among men who have sex with men in 2022. Clade 1b can be spread through close contact with an infected person. 

• The US Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) today announced several new steps to shore up its oversight of food processing facilities, especially in light of recent Listeria monocytogenes outbreaks and numerous recalls. A review of its processes identifies some steps that can be taken quickly under three categories: enhancing sampling, equipping inspectors with updated training and tools, and tightening oversight of regulated establishments, including those under state inspection models. In its statement, it spelled out the changes it will make over the next 30 days. 
• Merck today announced that the US Food and Drug Administration (FDA) has accepted its Biologics License Application (BLA) to review clesrovimab (MK-1654), a long-acting monoclonal antibody injection to protect infants from respiratory syncytial virus (RSV). The target action date is June 10, 2025, which company officials said, if approved, could pave the way for use during the 2025-2026 season. The drug is delivered as a single injection to protect infants during their first RSV season. If approved, the drug would be the second prophylactic monoclonal antibody for infants, alongside nirsevimab-alip (Beyfortus), which is made by AstraZeneca.
• The USDA  Animal and Plant Health Inspection Service (APHIS) yesterday said after a biennial review that it removed five select agents from its Biological Select Agents and Toxins (BSAT) list. They include Brucella abortus, Brucella suis, Brucella melitensis, African horse sickness virus, and Peronosclerospora philippinensis. It said the step removes regulatory barriers that help advance research on vaccines and diagnostics and that delisting the Brucella species doesn’t change the current biosafety level for lab work.