Study find urinary antigen testing underused in pneumonia patients

An analysis of almost 160,000 pneumonia patients in 170 US hospitals indicates that urinary antigen testing (UAT), a practice recommended by national guidelines to allow for antibiotic de-escalation in patients with community-acquired pneumonia (CAP), is not widely performed, researchers reported today in Clinical Infectious Diseases.

To determine adherence to UAT recommendations from the Infectious Diseases Society of America (IDSA) and the American Thoracic Society and to gauge whether UAT results affect prescribing behavior, researchers with Cleveland Clinic and the University of Massachusetts Medical School conducted a retrospective study of adult patients with CAP or healthcare-associated pneumonia admitted to 170 hospitals from 2010 through 2015.

Among 159,894 eligible admissions, 24,757 (15.5%) had UAT performed (18.4% of ICU and 15.3% of non-ICU patients). Among hospitals with more than 100 eligible patients, UAT testing proportions ranged from 0%-69%. Compared to patients with negative UAT, 7.2% with positive UAT more often had a positive Streptococcus pneumoniae culture (25.4% vs 1.9%, P < 0.001)—a result that should allow for rapid de-escalation of therapy—and less often had resistant bacteria (5.2% vs 6.8%, P < 0.05).

Of patients initially treated with broad-spectrum antibiotics, most were still receiving broad-spectrum therapy 3 days later, but UAT-positive patients more often had coverage narrowed (38.4% vs 17.0% UAT-negative and 14.6% untested patients, P < 0.001). In addition, the duration of vancomycin, piperacillin-tazobactam, and carbapenems were all shorter in response to a positive UAT. Hospital rate of UAT was strongly correlated with de-escalation following a positive test. Only three patients de-escalated after positive UAT were subsequently admitted to ICU.

The authors conclude, "Despite the test being inexpensive, accurate and rapid, UAT appears underused, but could be an important tool for antibiotic stewardship. Broader indications for testing featured in national guidelines might help to spread its use nationwide."
Oct 7 Clin Infect Dis abstract

Researchers suggest patients on laxatives should be tested for C diff

In another study published in Clinical Infectious Diseases, researchers with Beth Israel Deaconess Medical Center report that the recommendation against conducting Clostridioides difficile infection (CDI) stool testing on patients who've recently taken laxatives carries a potential for harm and should be re-evaluated.

To increase the relevance of a positive stool test for C difficile, the 2017 IDSA-Society for Healthcare Epidemiology of America (IDSA-SHEA) clinical guidelines emphasized testing only in patients likely to have true CDI; among the groups the guidelines recommended against testing were those who'd received a laxative in the previous 48 hours. But the authors of the study note that this recommendation rests on weak evidence, and that the guidelines don't define meaningful laxative use or allow room for clinical judgement when other features signal infection.

Out of concern that this recommendation might miss some CDI diagnoses, the researchers prospectively enrolled patients at Beth Israel Deaconess Medical Center with new-onset diarrhea and a positive C difficile nucleic acid amplification (NAAT) test, including patients who'd used a laxative within 48 hours prior to stool testing. They then assessed CDI recurrence and severe outcomes, including intensive care unit (ICU) admission, colectomy, and death, during the 40 days after diagnosis.

Overall, 209 patients with CDI were studied, 65 of whom (31%) had received laxatives. Among the patients receiving versus those not receiving laxatives, there were no significant differences in the proportion meeting severe CDI criteria by four severity scoring methods (66.2% vs 56.3%, respectively, P = 0.224). Similar rates of serious outcomes attributable to CDI, including death, ICU admission, and colectomy, were observed in the laxative and no laxative groups.   

"Had LAX 48 patients been excluded from testing as recommended by the IDSA-SHEA guidelines, diagnosis of CDI would have been missed in nearly one third of this cohort, 66.2% of whom met criteria for severe CDI by IDSA-SHEA scoring methods—including one death, one patient who required a colectomy, and seven patients who required treatment in an ICU due to CDI," the authors write. "It is likely that some of the other LAX 48 patients would also have suffered additional adverse outcomes due to delayed or missed diagnoses and treatment."

The authors say the issue should be investigated in larger multisite studies.
Oct 4 Clin Infect Dis abstract

Germany reports XDR Klebsiella pneumoniae in 4 hospitals

German public health authorities have confirmed a 17-case outbreak of extensively drug-resistant (XDR) Klebsiella pneunomiae in four hospitals, the European Centre for Disease Prevention and Control (ECDC) said today in its weekly communicable disease threats report.

Six patients are infected and 11 are carrying XDR K pneumoniae in the northeast state of Mecklenburg-West Pomerania, the ECDC said. The strain is resistant to all penicillins, ephalosporins, carbapenems, quinolones, aminoglycosides, and fosfomycin and colistin, officials said. But it is susceptible to chloramphenicol, tigecycline (though susceptibility is limited), and cefiderocol, an experimental antibiotic not yet approved in Europe.

The outbreak highlights "the worsening situation and the high risk for further spread of highly-resistant, hospital-adapted strains of carbapenem-resistant Enterobacteriaceae in the EU/EEA," the ECDC said. It added that the disease has very few remaining treatment options, and continent-wide enhanced control efforts are needed.

The ECDC said it is monitoring the event and seeking more information from German officials.
Oct 7 ECDC report