Stewardship / Resistance Scan for Sep 10, 2019

News brief

Study: Meropenem could be alternative treatment for bacterial meningitis

New data from a study by Swedish researchers indicates meropenem is an effective alternative empirical treatment option for adults who have community-acquired acute bacterial meningitis (ABM). The findings appeared yesterday in Antimicrobial Agents and Chemotherapy.

The study analyzed data on 623 Swedish adults diagnosed with ABM from 2008 through 2016 who were treated empirically with either cefotaxime plus ampicillin—which is recommended as the first-line treatment for ABM by the Swedish Infectious Disease Association—or meropenem. Propensity score matching was performed to adjust for baseline differences between the two groups. The primary end point was 30-day mortality, and secondary end points were 90-day mortality and unfavorable outcome at follow-up.

Among the 328 patients who received cefotaxime plus ampicillin, the 30-day mortality was 3.4%, compared with 6.4% in the patients treated with meropenem, and the corresponding figures for 90-day mortality were 4.6% and 8.1%, respectively. But the patients who received meropenem were older and more often presented with septic shock, and a lower proportion of them received adequate corticosteroids together with the initiation of antibiotics. In the propensity-matched patients, the 30-day mortality was 3.2% in the cefotaxime plus ampicillin group and 3.4% in the meropenem group.

For matched cases, the odds ratio (OR) for 30-day mortality for meropenem vs cefotaxime plus ampicillin was 1.15 (95% confidence interval [CI], 0.41 to 3.22, P = 0.79). The ORs for 90-day mortality and unfavorable outcome were 1.47 (95% CI, 0.62 to 3.52, P = 0.38) and 1.10 (95% CI, 0.75 to 1.63, P = 0.62).

The authors of the study say that while the findings support meropenem as an effective alternative for empirical treatment of ABM, cefotaxime plus ampicillin should remain the first-line treatment. "However, due to the importance of antibiotic stewardship, and the lack of benefit of meropenem on clinical outcomes in the majority of patients with ABM, third-generation cephalosporins should continue to be the cornerstone of empirical treatment of ABM," they conclude.
Sep 9 Antimicrob Agents Chemother abstract

Oral antibiotics linked to altered immune response to flu vaccine

A small study led by researchers from Stanford University and funded by the National Institutes of Allergy and Infectious Diseases (NIAID) suggests that oral antibiotics may alter the human immune response to the flu vaccine.

In the study, which was published in the journal Cell, the researchers set out to investigate the role of the human gut microbiota in shaping immune responses to the seasonal flu vaccine. They enrolled 22 healthy adults with high pre-existing immunity to the flu during the 2014-15 flu season, then randomized 11 participants to a 5-day oral cocktail of broad-spectrum antibiotics (neomycin, vancomycin, and metronidazole) 3 days prior to and 1 day after vaccination, with the aim of reducing gram-negative and anaerobic bacteria in the gut. They then collected biological samples for the following year and measured key aspects of the gut microbiome and the immune system.

Despite a significant reduction in gut bacterial load and bacterial diversity in the group that received antibiotics, there was no significant difference in antibody responses between the two groups. However, in a second study of 11 adults with low pre-existing flu immunity studied during the 2015-16 flu season, the researchers found a hindered response to the H1N1 A/California-specific strain of flu on day 90 and day 180 in the 5 participants who received antibiotics. No differences were observed for the two other flu strains.

The researchers also found that, in both groups that received antibiotics, there were changes to the immune system that promoted a pro-inflammatory state, similar to that seen in older adults who receive the flu vaccine.

"Here, we have demonstrated the potential for antibiotic-driven perturbation of the microbiome to influence immune responses to vaccination in healthy adults," the authors of the study write. "These findings should inform further research seeking to better understand mechanisms that control the interplay between the gut microbiota and our immune system."
Sep 5 Cell study
Sep 6 NIAID press release

News Scan for Sep 10, 2019

News brief

California bill toughening medical vaccine exemptions signed into law

California Governor Gavin Newsom yesterday signed two bills that limit medical exemptions for vaccines in schoolchildren.

One of the bills directs the California Department of Public Health (CDPH) to investigate doctors who grant five or more medical exemptions in a year, CNN reported today. The state will also investigate schools with an overall immunization rate of less than 95% and has new authority to revoke medical exemptions that are deemed inappropriate by a physician or public health officer.

The companion bill includes some changes that Newsom proposed, which includes allowing a child with a medical exemption issued before Jan 1, 2020, to be allowed to continue going to school until he or she reaches the next grade level.

California is among a few states that don't offer personal, philosophical, or religious exemptions from school vaccination requirements. According to CNN, the number of unvaccinated California schoolchildren declined after it outlawed nonmedical exemptions.

The state's actions come during a year when US measles cases have reached their highest level since 1992. About 75% of the cases have occurred in New York, primarily reflecting outbreaks in Orthodox Jewish communities. According to the CDPH, the state has recorded 67 measles cases as of Sep 4, of which 38 were part of five outbreaks that have now ended.
Sep 10 CNN report
CDPH measles page

New studies suggest presenteeism common in health workers ill with flu

Two new studies, one from the United States and one from Australia, suggest a substantial percentage of healthcare providers report to work when sick with influenza-like illnesses (ILIs).

Iowa investigators published in the Antimicrobial Resistance & Infection Control a survey of 127 medical students, resident physicians, and faculty physicians about presenteeism (working while sick). They found that 60% felt obligated to work while sick and 33% felt obligate to work with ILI symptoms.

Many participants (83%) in the study said they worked out of fear of creating more work for colleagues. Despite that perception—which was even stronger in medical student and residents—81% still recognized the need to avoid spreading infections to patients, and 75% noted the goal of not infecting coworkers.

"The results of our study demonstrate an ethical tension between an obligation to work and an obligation not to harm," the authors concluded. They note that Centers for Disease Control and Prevention guidelines state that healthcare workers who have fever and respiratory symptoms should not work with patients and should be excluded from work until they are afebrile for at least 24 hours.

In a second study based in Queensland, Australia, researchers found 14.1% of healthcare workers worked while ill with influenza, including about a quarter of physicians. Physicians were also more likely to take a shortened sick leave compared with other healthcare personnel.

The study was published in the American Journal of Infection Control and is based on laboratory-confirmed influenza cases and history of sick leave among health workers in Queensland from 2009 through 2015.
Sep 5 Antimicrob Resist Infect Control study
Sep 9 Am J Infect Control study

Vietnam reports H5N6 avian flu outbreak in poultry

Vietnam's agriculture ministry reported a highly pathogenic H5N6 outbreak at in village birds in Ben Tre province in the southern part of the country, according to a Sep 8 notification from the World Organization for Animal Health (OIE).

The outbreak began on Aug 18, killing 138 of 1,026 susceptible birds. The survivors were culled, and authorities also increased surveillance and disinfected the affected areas.

The country's last H5N6 outbreak occurred in the middle of August, striking village birds in Vung Tau province, also in southern Vietnam. H5N6 has been identified in poultry outbreaks in China and a handful of other Asian nations, but China is the only country that has reported human cases, which are often severe or fatal.
Sep 8 OIE report