As the US Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) end their investigation into the June Listeria outbreak tied to soft cheese, the FDA is reporting a new outbreak, this one involving Salmonella from an unidentified food source. The CDC has also released updated case counts for several smaller Cyclospora outbreaks.

Yesterday, the two agencies declared the four-state Listeria monocytogenes outbreak traced to soft cheese over after reporting three new cases and four new hospitalizations, for a total of 15 and 14, respectively. One person died. The cheese manufacturer, Maryland-based Clover Hill Dairy, recalled its ricotta-like requeson cheese and all other cheese products in June. 

Also yesterday, the FDA reported a new 84-case Salmonella Newport outbreak tied to a yet-to-be-identified food source. No other details have been released.

The FDA updated case counts for three Cyclospora outbreaks with unknown food sources, adding five, two, and one cases, for totals of 22, 203, and 28, respectively. 

The case total for all US summer Cyclospora outbreaks, including the one linked to contaminated iceberg lettuce, is now 17,180 after the CDC added 3,285 infections this week. The CDC also said it is investigating another 11,844 cases that are not yet confirmed. At least two people have died of cyclosporiasis this summer, and 922 have been hospitalized.

A study conducted at four hospitals in Atlanta found that improved hand hygiene had no impact on detection of multidrug-resistant organisms (MDROs), researchers reported today in Infection Control & Hospital Epidemiology.

For the study, a team led by researchers at Emory University School of Medicine analyzed correlations between monthly unit-level hand hygiene adherence and rates of hospital-onset MDROs and other pathogens of epidemiologic significance (MDRO+) that can cause healthcare-associated infections (HAIs). Hand hygiene adherence was determined by an electronic monitoring system in patients’ rooms that records whether a healthcare worker dispensed hand hygiene product after entering the room. 

The study authors note that while it’s widely accepted that high hand hygiene adherence reduces HAI incidence, many of the studies looking at the relationship between the two often rely on direct observation of hand hygiene adherence, which can be prone to overestimates.

“The limitations of direct observation have generated interest in alternative methods for hand hygiene monitoring,” they wrote. “Automated hand hygiene monitoring systems (AHHMS) are an appealing solution to overcome the pitfalls of direct observation.”

More than 22.7 million hand hygiene opportunities were recorded by the AHHMS during the study period: January 2021 through September 2022. The mean monthly hand hygiene adherence rate increased from 41% in January 2021 to 57% in September 2022 on average across all units and facilities. A total of 1,847 MDRO+ detections were observed in 752,341 patient days, with a median composite MDRO+ rate of 1.7 per 1,000 patient-days.

Despite the hand hygiene improvement, the researchers were unable to demonstrate a clear unit-level inverse association between hand hygiene adherence and MDRO+ detection (rate ratio, 1.01). They say the results like reflect the “complex interaction between the two variable and unmeasured confounders.”

“The interplay between hand hygiene, infection prevention efforts, and MDRO acquisition is complex, and an absence of proof does not negate the importance of hand hygiene,” they wrote.