A study conducted in a New York City health system identified several patients infected with dual-carbapenemase–producing organisms (DCPOs), researchers reported late last week in JAC-Antimicrobial Resistance.

In the study, researchers at Icahn School of Medicine at Mount Sinai used rapid molecular testing to identify 26 DCPO isolates from 13 patients treated at Mount Sinai Hospital from 2018 through 2021. Twenty-four of the isolates were from the Enterobacterales order (22 Klebsiella pneumoniae, 1 Escherichia coli, and 1 Enterobacter isolate) and 2 were Pseudomonas aeruginosa. The most common carbapenemase combination was bla_NDM/bla_OXA-48-like, which was found in 16 isolates, and whole-genome sequencing revealed that the DCPOs were located on distinct plasmids.

All 26 isolates were resistant to penicillins, cephalosporins, ampicillin/sulbactam, and piperacillin/tazobactam, and 7 were non-susceptible to all antibiotics tested.

Previous hospitalization, antibiotic exposure common

Analysis of patient data showed that 11 of the patients had been hospitalized in the prior year (7 in the intensive care unit) and had received antibiotics within the last month, 7 were from foreign countries, and all had at least one underlying condition. High blood pressure, kidney disease, and diabetes were the most frequently seen comorbidities. Six of the patients died, with two of the deaths directly attributed to the DCPO infection.

The study authors say the findings are concerning, because DCPOs further compromise the already limited treatment options for carbapenemase-producing organisms and could threaten the utility of newer antibiotics. Furthermore, their location on plasmids could facilitate horizontal gene transfer and lead to multispecies dissemination of DCPOs.

"Infectious diseases physicians should be aware of this threat, as our study shows high mortality in patients infected or colonized with DCPOs," they wrote. "Further research into appropriate management of infections caused by DCPOs is needed."

Yesterday in the Journal of Infectious Diseases, researchers described a 2016 mpox outbreak that affected 20 captive chimpanzees at a sanctuary in central Cameroon.

At the time of the clade 1 outbreak in August through October, the sanctuary housed about 300 chimpanzees, gorillas, and monkeys in 18 groups. Mpox affected 20 of 23 adult and younger chimpanzees (14 male and 9 female) in one group. No animals had been moved into or out of the group in the previous 6 months.

Better monitoring, control measures needed

From August to September, 3 chimpanzees were confirmed to have mpox, and 17 had probable cases, for an 87% attack rate. The most common signs were rash (90%), lethargy (85%), and facial or peri-laryngeal swelling (70%). Two of the animals died, for a case-fatality rate of 10%. The rest of the chimpanzees recovered and were considered no longer infectious by late October.

Control measures should include quarantining affected animals, limiting human contacts, surveillance of humans and animals, use of personal protective equipment, and regular decontamination of enclosures.

After the first mpox case was detected, the sanctuary reported it to the Cameroon Epidemiological Network for Animal Diseases, and the onsite veterinarian documented daily signs, dates of onset and death, movements between cages, and treatment in the affected group. Nose-throat and rectal swabs were collected from chimpanzees who died or were immobilized for treatment.

For the 17 unaffected groups, caretakers visually inspected each animal each day for mpox signs, behavioral changes, and night shelter use, and a veterinarian did the same at least twice a week. Animals were quarantined if they showed mpox signs or had direct or indirect contact with the affected group.

Animal caretakers were monitored daily for mpox signs for 17 days; none developed a characteristic rash or fever.

"There is a need for increased awareness and a One Health approach to preparation for outbreaks in wildlife rescue centers in primate range states were MPXV [mpox virus] occurs," the researchers wrote. "Control measures should include quarantining affected animals, limiting human contacts, surveillance of humans and animals, use of personal protective equipment, and regular decontamination of enclosures."

Hong Kong researchers estimate that 33.6% of the adult population had COVID-19 in 2022, 72.1% with no symptoms, according to an analysis published yesterday in Emerging Infectious Diseases.

Chinese University of Hong Kong investigators examined the seroprevalence of open reading frame 8 (ORF8) antigens against SARS-CoV-2 to estimate the number of people infected during a spike in Omicron BA.2 variant cases from March to June 2022. In late February 2022, the government mandated self-reporting of positive rapid antigen testing (RAT).

A total of 1,028 volunteers who reported no history of COVID-19 infection gave plasma samples for enzyme-linked immunosorbent assay (ELISA) with ORF8 protein as an antigen. The researchers estimated infections using a model based on rates of positive ELISAs relative to the number of patient-reported cases from the Hong Kong Department of Health.

The median participant age was 50 years, 63.9% were women, and all but one reported receiving more than two doses of COVID-19 vaccines.

'Not surprising' Omicron wave was uncontrollable

Of all participants, 2.5% had evidence of a previous COVID-19 infection. Among the total population, 16.2% were reported to have had COVID-19 by RAT (6.1%) or reverse transcription polymerase chain reaction (RT-PCR; 10.1%).

Public health agencies need to take into account the potential for substantial undercount of actual numbers of infections when considering the commitment of resources to prevent and control outbreaks.

Using estimates from their statistical model, the authors inferred that 33.6% (95% credible interval, 32.1% to 34.8%) of the 7.5 million Hong Kong residents (roughly 2.5 million) contracted COVID-19 from January to June 2022. They estimated that 41.8% of reported infections and 72.1% of total cases were asymptomatic.

"With such a large number of unrecognized cases circulating the virus in the community, it was not surprising that the Omicron outbreak was uncontrollable, even though stringent measures, such as contact tracing and quarantine for close contacts, continued to be in effect," the authors wrote. "Public health agencies need to take into account the potential for substantial undercount of actual numbers of infections when considering the commitment of resources to prevent and control outbreaks."