A letter published yesterday in the New England Journal of Medicine describes 16 adult cases of mpox seen in Bayelsa, Nigeria, among casual heterosexual partners, confirming that heterosexual intercourse plays a role in transmission of the virus, though not nearly to the degree that male-to-male sexual contact has.

The authors describe 16 adult cases of mpox seen in a hospital in Bayelsa from June through October 2022. The adults reported having unprotected sexual contact with partners who had laboratory-confirmed mpox within 1 month before the onset of their illness. All case-patients had a genital rash, 12 of the 16 had fever, and none reported any household or animal contact with mpox cases.

Altogether there were seven linked transmission chains seen, including three patients who had linked partners who were female sex workers, the authors said. Six (38%) of the case-patients had sexual partners who were symptomatic, 5 (31%) had partners who were presymptomatic or asymptomatic, and 5 (31%) had partners with an unknown symptom status.

"Although phylogenetic data were not available, the temporal relationship between sexual activity and the onset of symptoms, the localization of lesions to the genital area, and the absence of previous animal exposures support human-to-human transmission of MPXV through sexual contact," the authors wrote.

None of the case-patients was HIV positive, and none died. Because the vast majority of recent mpox infections have occurred in men who have sex with men, the authors warn that heterosexual couples may be underdiagnosed, especially if they have an atypical genital rash.

Researchers with Johns Hopkins University School of Medicine reported yesterday that they identified what they believe is the first clinical case in the United States of a patient with an infection showing resistance to all available beta-lactam antibiotic regimens.

In a case report published in Open Forum Infectious Diseases, the researchers said the 66-year-old man had traveled to India to receive a kidney transplant in January 2022 and was treated at Johns Hopkins Health System for cystitis (bladder inflammation) several time from June to September 2022. The man then developed pyelonephritis (kidney infection) caused by New Delhi metallo-beta-lactamase (NDM)-producing Escherichia coli.

Although antimicrobial susceptibility testing results indicated resistance to both cefiderocol and ceftazidime-avibactam plus aztreonam (CZA-ATM)—the preferred treatment regimens for NDM-producing infections—he was continued on CZA-ATM and experienced a relapse 3 weeks later.

Further antimicrobial susceptibility testing indicated resistance to all beta-lactams. Whole-genome sequencing (WGS) of E coli isolates collected from the patient after his kidney transplant and during treatment for the infection showed they belonged to sequence type (ST)167, which has been recognized as an international high-risk clone. The ST contained a single copy of the blaNDM-5 gene, along with genes conferring resistance to penicillins, early-generation cephalosporins, aminoglycosides, trimethoprim, sulfamethoxazole, and macrolides.

The combination of resistance and virulence makes them ripe for global dissemination.

WGS also revealed a mutation in the penicillin binding protein 3, mutant CirA proteins, and expression of the blaCMY gene—a combination the study authors say almost ensures resistance to cefiderocol and CZA-ATM. They believe the patient was likely colonized with the NDM-producing E coli while in India.

"Regardless of the likely culprits of the pan-β-lactam resistance observed, this case is worrisome given that E. coli ST167 clinical isolates harboring blaNDM-5 genes are increasingly being recognized as an international high-risk clone," they wrote. "E. coli ST167 have been associated with unique virulence factors (e.g., novel capsular synthesis gene clusters); the combination of resistance and virulence makes them ripe for global dissemination."

The TB Alliance announced yesterday that it will receive up to $3.9 million in funding from the Cystic Fibrosis Foundation to investigate a compound with the potential to treat nontuberculosis mycobacteria (NTM) infections.

The funding will be used to conduct preclinical testing on a novel oxazolidinone inhibitor that was identified by researchers with the TB Alliance and Johns Hopkins University in 2020 as having the potential to treat two types of NTM, Mycobacterium abscessus and Mycobacterium avium complex. The two species cause the vast majority of NTM lung infections in people with cystic fibrosis.

Researchers will be looking to see whether the synthetic antibiotic is more effective against NTM infections than linezolid, the antibiotic currently used to treat M abscessus infections.

Identifying this new compound will allow our researchers to potentially develop a new, improved treatment for NTM infections.

"At TB Alliance, we are focused on discovering and developing novel treatments for tuberculosis. Through this work, we found several possible compounds that had the potential to treat NTMs, which are related to the TB bacteria," Nader Fotouhi, PhD, senior vice president and chief scientific officer at TB Alliance, said in a press release. "Identifying this new compound will allow our researchers to potentially develop a new, improved treatment for NTM infections that may help people with cystic fibrosis."