Implementation of a diagnostic stewardship intervention for suspected pneumonia at a Michigan hospital was associated with a reduction in positive respiratory cultures and broad-spectrum antibiotic use, researchers reported last week in Clinical Microbiology and Infection.

Using a quasi-experimental clinical trial format, researchers at the University of Michigan Medical School examined the impact of a bundled, ventilator-associated pneumonia–specific diagnostic stewardship intervention (VAP-DSI) implemented at Michigan Medicine University Hospital. The goal of the VAP-DSI was to reduce the rate of diagnostic error in VAP, which is responsible for most antibiotic use in the intensive care unit but is frequently misdiagnosed because of diagnostic errors.

"Because respiratory cultures are fundamental to the management of VAP—a serious infection affecting critically ill patients with limited margin for diagnostic error—efforts to regulate their use have proven historically challenging," the study authors wrote. "The current VAP diagnostic paradigm, however, is fraught with overdiagnosis and consequent antimicrobial overuse." 

Among the bundled interventions in the VAP-DSI was gatekeeping access to respiratory culture ordering.

Fewer antibiotic days of therapy

Comparing the 5 years before the intervention (2017 to 2022) with 1 year post-intervention (2022 to 2023), researchers examined rates of adverse safety outcomes, positive respiratory cultures, and antimicrobial use in mechanically ventilated patients (MVPs). A total of 687 MVPs were admitted in the post-intervention period, compared with 4,205 in the pre-intervention period.

VAP-DSI was not associated with an observed increase in adverse safety outcomes, such as ventilator-associated events or deaths per 1,000 MVP days, but it was associated with a 20% relative reduction in positive respiratory cultures per MVP days (pre-intervention rate 127, post-intervention rate 102). In addition, antibiotic days of therapy fell from 1,199 per 1,000 MVP days to 1,149.

Although they couldn't determine the relative impact of each component of the intervention, the authors suggest the reduction in the rate of positive respiratory cultures was primarily driven by reduced test ordering.

"This study provides proof-of-concept that carefully constructed VAP-DSIs represent safe and feasible avenues for ASPs," they wrote.

Another infant formula is being recalled for possible contamination, this time with Cronobacter sakazakii. The bacteria can cause rare bloodstream and central nervous system infections and has been associated with severe intestinal infections and even death.

Mead Johnson Nutrition (Canada) Co is recalling certain Enfamil brand Nutramigen A+ LGG Hypoallergenic formulas from the Canadian marketplace. The Canadian Food Inspection Agency said the formula was distributed nationally and has a sell-by date of January 2025.

At the time of the recall, no illnesses linked to the formula were reported.

The latest recall follows 2 years of international formula recalls and shortages, prompting the US Food and Drug Administration to publish new strategies last March to ensure the safety of infant formula.

Five states reported more highly pathogenic avian influenza outbreaks in poultry over the last few days, including California where more layer farms were hit by the virus, according to the latest updates from the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS).

Two more outbreaks were reported from layer farms in Sonoma County, California, one with 54,000 birds and the other with 37,200. Also, officials reported an outbreak at a layer pullet farm in Marin County that houses 151,000 birds. Over the past month, California has been the state suffering the most poultry losses.

Elsewhere, South Dakota reported another outbreak at a commercial gamebird producer, this time in Edmunds County at a location that has 1,400 birds. Also, Missouri, Montana, and Texas reported outbreaks involving backyard poultry.

Since the H5N1 outbreaks in US poultry began in February 2022, the events have led to a loss of a record 79.7 million birds across 47 states.

Health officials have monitored more than 7,000 people

Sporadic H5N1 infections in humans have occurred in people exposed to infected poultry or their environments, including a positive respiratory specimen collected from a poultry culler in Colorado back in April 2022.

Since then, the Centers for Disease Control and Prevention (CDC) and its state and local partners have monitored more than 7,000 people in 52 jurisdictions who were exposed to infected birds or sick or dead mammals, the group said in a December 29 technical update. Of 175 people who had symptoms, only the Colorado patient tested positive for the virus.

Though the threat to human health remains low, the CDC said widespread geographic prevalence in wild birds and poultry poses an exposure risk to people and mammals, which could result in viral evolution or reassortment, and could change the current risk assessment.