A study of hospitalized Veterans Affairs (VA) patients found that combination therapy was not associated with decreased mortality for multidrug-resistant (MDR) Acinetobacter infections, researchers reported yesterday in Antimicrobial Stewardship & Healthcare Epidemiology.

The retrospective cohort study, led by a team of VA researchers, looked at VA patients who were hospitalized with MDR Acinetobacter bacteremia and received antibiotics 2 days prior through 5 days after the culture date from 2012 through 2018. The aim was to assess the impact of antibiotic treatments on in-hospital, 30-day, and 1-year mortality and costs.

Insignificant impact

MDR Acinetobacter spp. was identified in 184 patients. Most patients were older (mean age, 67 years), White, non-Hispanic men. The vast majority of cultures identified were A baumannii (90%), while 3% were A lwoffii, and 7% were other Acinetobacter species. Half (50.5%) of the infected patients died in hospital, 44% within 30 days, and 67.9% within 1 year.

Penicillins/beta-lactamase inhibitor combinations (51.1%) and carbapenems (51.6%) were the most prescribed antibiotics. In unadjusted analysis, extended-spectrum cephalosporins and penicillins/beta-lactamase inhibitor combinations were associated with a decreased odds of 30-day mortality, but the effect was insignificant after adjustment (adjusted odds ratio (aOR), 0.47; 95% confidence interval [CI], 0.21 to 1.05 and aOR, 0.75; 95% CI, 0.37 to 1.53, respectively). There was no association between combination therapy vs monotherapy and 30-day mortality (aOR, 1.55; 95% CI, 0.72 to 3.32).

The results are noteworthy, the authors say, because while the Sanford Guide and the Infectious Diseases Society of America recommend combination therapy (high-dose ampicillin-sulbactam plus an additional agent) for treating severe MDR Acinetobacter infections, the findings add to evidence from prior studies that have found limited improved clinical outcomes with combination therapy.

"Our results provide additional comparative effectiveness demonstrating a lack of benefit to combination therapy given within −2 through +5 days from the culture date," they wrote.

A study of more than 25,000 hospitals encounters found that staying in a hospital bed that previously had a patient with Clostridioides difficile infection (CDI) was associated with an increased risk of hospital-onset (HO)-CDI, researchers reported today in Infection Control & Hospital Epidemiology.

In the study, researchers from Emory University School of Medicine used a real-time location system to track the movement of hospital beds at two academic medical centers from April 2018 to August 2019. They defined patients as being exposed to a potentially contaminated bed if, within the 7 days preceding their HO-CDI diagnosis, they had stayed in a bed that held an occupant with CDI in the previous 90 days. They used multivariable logistics regression to determine whether staying in a contaminated bed was associated with HO-CDI after controlling for time at risk and intensive care unit (ICU) admission.

Strong association with contaminated beds, rooms

Among 25,032 hospital encounters with 18,860 unique patients (51.7% female, 52.9% Black, median age 61 years), the researchers identified 237 cases of HO-CDI. Exposure to a contaminated bed was associated with HO-CDI in unadjusted analyses (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.4 to 2.31) and adjusted analyses (OR, 1.5; 95% CI, 1.2 to 2.0). Even after varying the length of time the researchers assumed the bed would remain contaminated (from 90 days to 60, 30, 14, or 7 days), the association persisted.

The analysis also found that exposure to a contaminated hospital room was associated with HO-CDI in both unadjusted (OR, 1.9; 95% CI, 1.5 to 2.5) and adjusted (OR, 1.5; 95% CI, 1.1 to 1.9) analyses, and that 62% of the relationship between HO-CDI and exposure to a contaminated bed was due to both direct and indirect interaction with a contaminated hospital room.

"New technologies or cleaning and disinfection methods that can better eradicate C. difficile spores from a hospital bed and/or the surrounding healthcare environment may lead to significant reductions in healthcare transmission of C. difficile and decrease rates of HO-CDI," the study authors concluded.

The World Health Organization (WHO) technical advisory group on COVID-19 vaccine composition met last week to review the latest SARS-CoV-2 genetic changes and assess if any vaccine changes are needed, and today the group recommended sticking with the current monovalent XBB.1.5 antigen.

Their advice came with caveats about knowledge gaps about efficacy of the current vaccines, genomic surveillance, and aspects of immune response apart from neutralization antibody titers. The group currently weighs in on vaccine composition twice a year. In its last meeting in May, it recommended use of a monovalent XBB lineage vaccine antigen such as XBB.1.5.

As of December 2, XBB-descendant viruses made up 73% of sequenced viruses and are declining against the backdrop of steadily rising BA.2.86 detections, a group that includes JN.1, that currently make up 17% of samples. Scientists continue to see more evolution in the spike protein of newer XBB and BA.2.86 variants.

Serologic testing on the blood of humans who received the monovalent XBB.1.5 vaccine, with or without prior infection, neutralized XBB lineages, as well as BA.2.86 and JN.1. However, the group emphasized that there are only limited data on cross-neutralization against JN.1.

Though it recommended retaining the current XBB.1.5 vaccine strain, it said other formulations or platforms that prompt robust neutralization antibody responses to currently circulating variants, including XBB and BA.2.86 lineages, can also be considered. And the committee encouraged scientists to collect more data on XBB.1.5 vaccine immune response and clinical endpoints, strengthen surveillance regarding emerging variants, and evaluate new vaccine antigens, especially ones emerging from XBB and BA.2.86 lineages.

Global flu activity continues to rise, led by increases in several Northern Hemisphere countries in North America, Europe, and Asia, the World Health Organization (WHO) said this week in an update that roughly covers the latter half of November.

Influenza A made up 87.8% of positive respiratory samples at national flu labs over the reporting period. And though 81.4% of subtyped influenza A viruses globally were the H3N2 strain, the 2009 H1N1 subtype is dominant in North America, where levels are generally above baseline and at expected levels for this time of year.

Europe's activity is still generally low but on the rise, with four countries reporting widespread flu: Denmark, Norway, Spain, and the United Kingdom, with H3N2 and H1N1 detected at similar levels.

Eastern Asia's flu levels continue to rise, mainly due to activity in South Korea, as well as China, where flu is tracking above expected levels, with detections still rising in the northern provinces. In Western Asia, elevated flu levels continue in a handful of Arabian Peninsula countries, with detections increasing in Qatar.

In Africa, flu positives—mainly H3N2—rose in East Africa, including Ethiopia and Madagascar. And in North Africa, levels rose, mainly due to activity in Egypt.

The rate of invasive pneumococcal disease (IPD) in children plummeted 72% from 2002 to 2021 and continued to fall after the 7-valent (7-strain) pneumococcal conjugate vaccine (PCV7) was replaced by the 13-valent version (PCV13), a Yale University–led team reports today in Pediatrics.

The study analyzed data on IPD among children younger than 18 years from a Massachusetts surveillance system. The team serotyped Streptococcus pneumoniae isolates from normally sterile sites and evaluated them for antimicrobial susceptibility.

PCV7 was rolled out in the United States in 2000 and was replaced by PCV13 in 2010. Vaccine uptake in Massachusetts among children younger than 3 years with three or more doses is 92%, and receipt of at least four doses is 81% to 91%.

The researchers defined protective vaccination as receipt of two or more doses for children younger than 1 year, three doses in the first year of life, or one dose after 1 year.

IPD dipped to 1.6 per 100,000 amid pandemic

In all, 1,347 IPD cases were identified. Rates in children fell 72% (incidence rate ratio, 0.28) and continued to decline after replacement of PCV7 with PCV13 (incidence rate ratio, 0.25 in the late PCV7 vs the late PCV13 era).

In the COVID-19 pandemic years 2020 to 2021, IPD incidence dipped to a low of 1.6 per 100,000 children. In the PCV13 era, 30.3% of infected children older than 5 years had at least one underlying medical condition.

Robust ongoing surveillance networks are critical for identifying emerging serotypes and development of next-generation vaccine formulations.

Serotypes 19A and 7F made up 48.9% of infections before replacement with PCV13. Serotype 3 (8.6%) and non-PCV13 serotypes 15B/C (10.8%), 33F (8.0%), 23B (0.8%), and 35B (4.7%) caused 37.8% of cases in the PCV13 era. Nonsusceptibility to penicillin continued to fall (9.8% vs 5.3% in the pre-/late PCV13 era) but has become more common among non-PCV13 serotypes than vaccine serotypes (14.8% vs 1.4%).

"Nonvaccine serotypes continue to emerge under vaccine-selective and antibiotic-selective pressures, limiting overall vaccine effectiveness against pneumococcal disease," the authors wrote. "Robust ongoing surveillance networks are critical for identifying emerging serotypes and development of next-generation vaccine formulations."