A study in Saudi Arabia indicates that being colonized with a multidrug-resistant organism (MDRO) is associated with a significantly increased risk of subsequent MDRO infection, researchers reported this week in Infection Control & Hospital Epidemiology.

The study, conducted at a tertiary care facility in Riyadh, included patients in active surveillance testing (AST) for carbapenem-resistant Enterobacterales (CRE), methicillin-resistant Staphylococcus aureus (MRSA), or vancomycin-resistant enterococci (VRE). Researchers at the hospital compared the risk of developing a relevant invasive infection within 365 days of the AST result between colonized and non-colonized groups. 

While previous studies have documented the link between MDRO colonization and increased risk of subsequent infection, the authors of the study note that little is known about the extent of MDRO colonization in Saudi Arabia's hospitals.

VRE-colonized patients 22% more likely to develop VRE infection

A total of 19,134 ASTs conducted in 2021 were included in the analysis—4,919 for CRE, 8,303 for MRSA, and 5,912 for VRE. Nine percent of patients screened for CRE were colonized, compared with 10% for MRSA and 14% for VRE. Patient demographics were similar between colonized and non-colonized groups.

Compared with the non-colonized group, patients colonized with CRE were 4.6 times (95% confidence interval [CI], 3.3 to 6.4) more likely to develop a CRE infection, with 88% of CRE-colonized patients developing an infection with the same carbapenemase gene. MRSA-colonized patients were 8.2 times (95% CI, 4.7 to 14.3) more likely to develop a MRSA infection than non-colonized patients, and VRE-colonized patients were 22 times (95% CI, 10.1 to 48.1) more likely to develop a VRE infection. 

The median time from AST to clinical infection was reduced for patients colonized with CRE and VRE, while MRSA-colonized patients took longer to develop a clinical MRSA infection compared with non-colonized patients.

The authors say the findings highlight the need to implement AST for MDRO colonization and rigorous infection control measures to effectively mitigate transmission of these dangerous pathogens.

Los Angeles County, California, yesterday reported two more locally acquired dengue infections that are part of a cluster of cases from Baldwin Park, for a total of five since September 9.

A case in Panorama City, located about 40 miles west of Baldwin Park, reported on September 25 and two cases in El Monte earlier in October aren't considered related to the Baldwin cluster. None of the affected patients had a history of travel to tropical regions endemic for the mosquito-borne virus.

"This small local outbreak raises concerns about the ongoing spread of dengue and the potential for spread to other areas of LA County," LA Public Health said on X. "Everyone in LA County should take action to prevent mosquito bites and mosquito breeding."

On October 6, San Diego County announced the detection of locally acquired dengue in an Escondido resident. Pasadena and Long Beach, California, each reported one such case in fall 2023.

Mosquito avoidance urged

In the press release, Muntu Davis, MD, MPH, Los Angeles County health officer, said mosquito-bite prevention "can be as simple as using insect repellent to prevent mosquito bites, eliminating any standing water around your home where mosquitoes can breed, and keeping your home mosquito-free by using or fixing screens on your doors and windows."

This small local outbreak raises concerns about the ongoing spread of dengue and the potential for spread to other areas of LA County.

Dengue fever typically causes no symptoms but may lead to high fever, severe headache, pain behind the eyes, joint and muscle pain, rash, and slight bleeding. In about 1 in 20 infections, it results in shock, severe bleeding, and organ damage. While no antiviral drug is available to treat dengue, there is a vaccine, but it is not approved for use in US travelers visiting but not living in an endemic area.

Rwandan scientists and partners from the World Health Organization (WHO) have launched the world’s first clinical trials for Marburg virus disease treatment. Currently, there are no approved treatments or vaccines against Marburg virus, though a clinical trial of an investigational Marburg virus vaccine from the Sabin Vaccine Institute recently launched in the country. 

Matshidiso Moeti, MBBS, head of the WHO Africa regional office, said on X today that the clinical trial will test the efficacy and safety of remdesivir as well as MBP091, a monoclonal antibody that targets Marburg virus. The drug was developed by Mapp Biopharmaceutical with support from the Biomedical Advanced Research and Development Authority (BARDA), which is part of the US Department of Health and Human Services (HHS) Administration for Strategic Preparedness and Response (ASPR).

Health ministry reports no new cases or deaths

For the third day in a row, Rwanda’s health ministry reported no new Marburg cases or deaths, keeping the outbreak total at 62 infections, 15 of them fatal. Since the outbreak was first announced, all new cases have been related to a hospital cluster and their contacts in Kigali. Officials said there is no evidence of community spread.

Eight more people recovered from their illnesses. Health workers have also vaccinated 856 people as part of the clinical trial of the Sabin Vaccine Institute’s investigational Marburg virus vaccine.

The Michigan Department of Agriculture and Rural Development (MDARD) today announced another avian flu outbreak in dairy cattle, its first since early September.

The state’s latest outbreak occurred at a farm in Clinton County, which is near Lansing. Michigan has now reported 30 outbreaks in dairy cattle.

Testing at the Michigan State University Veterinary Diagnostic Laboratory initially identified the virus, and samples will be sent for confirmation testing to the US Department of Agriculture (USDA) National Veterinary Services Laboratory.

If confirmed as H5N1, the detection would push the number of US outbreaks in dairy cattle to 306 from 14 states.

USDA confirms more detections in Florida dolphins

In other avian flu developments, the USDA’s Animal and Plant Health Inspection Service has confirmed three more H5N1 detections in bottlenose dolphins, which were sampled last December and January. All involved animals are from Brevard County.

The H5N1 detections in US dolphins are the first since 2022, when the virus was found in a bottlenose from Florida’s Dixie County. The clade 2.3.4.4b H5N1 virus is known to infect sea mammals, including seals and sea lions, among several other mammal species.