Stewardship / Resistance Scan for Nov 09, 2017

Antibiotics and subsequent sepsis
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MCR surveillance in California

Increased sepsis risk found in patients previously treated with antibiotics

A significant increase in cases of severe sepsis and septic shock within 90 days of hospital discharge was observed among patients exposed to antibiotics during their previous hospital stay, researchers with the Centers for Disease Control and Prevention reported today in Clinical Infectious Diseases.

For the study, the researchers obtained hospital discharge and drug use data from a large database that contains billing records from more than 500 US hospitals. They included hospital admissions for all patients discharged during two periods: January 2007 through September 2010 and January 2011 through September 2014. The purpose was to examine the association between the use of certain antibiotics during the initial hospital stay and the risk of post-discharge sepsis, using a multivariable logistic regression model that controlled for potential confounding factors. The antibiotics were categorized into high-risk, low-risk, and control categories, based on association with clinically important microbiome disruption.

Among 516 hospitals, the researchers randomly selected more than 12 million patients who had a hospital stay during the study period and identified 21,247 (0.17%) who had severe sepsis or septic shock during within 90 days of their index stay. Among patients with exposure to a high-risk antibiotic agent—including third- and fourth-generation cephalosporins, fluoroquinolones, licnosamides, beta-lactam/beta-lactamase inhibitor combinations, oral vancomycin, and carbapenems—during the index stay, the proportion of patients with severe sepsis post-discharge was 0.3%, compared with 0.1% of patients with no antibiotic exposure.

In the multivariable logistics regression model, exposure to a high-risk antibiotic was associated with a 65% increased risk of severe sepsis within 90 days of discharge (odds ratio [OR], 1.65). Exposure to low-risk and control antibiotics were not as strongly associated with severe sepsis (OR, 1.07 and OR, 1.22, respectively). Patients exposed to four or more antibiotic classes or more than 14 days of antibiotic therapy had over twice the risk of severe sepsis (OR, 2.23 and OR, 2.17, respectively).

The authors say the findings support the hypothesis that microbiota disruption is associated with an increased risk of severe sepsis post-hospital discharge. They also argue that the study makes a case for increased antibiotic stewardship, given that 30% to 50% of antibiotic use in hospitals is estimated to be inappropriate. "This study builds on a growing evidence base suggesting that increased stewardship efforts in hospitals may not only prevent antimicrobial resistance, CDI [Clostridium difficile infection] and other adverse effects, but also reduce other unwanted outcomes potentially related to disruption of the microbiota, including sepsis," they write.
Nov 9 Clin Infect Dis study

 

Study finds no MCR genes in Shiga toxin–producing E coli in California

Molecular screening of 1,000 Shiga toxin–producing Escherichia coli (STEC) isolates from an agricultural region in California detected no colistin resistance genes, investigators from the US Department of Agriculture reported yesterday in PLoS One.

The STEC isolates were recovered from livestock, wildlife, produce, and other environmental sources in California's central coast from 2006 through 2014. They included STEC O157 and non-O157. STEC is recognized as the leading cause of foodborne illness outbreaks in the United States.

The investigators screened the isolates for the presence of MCR-1 and MCR-2, the plasmid-mediated colistin-resistance genes that were first identified in Chinese pigs in 2016 and since then have spread around the world. Recent studies have found the presence of MCR-1 in some STEC isolates.

The results obtained via polymerase chain reaction (PCR) testing showed that all 1,000 STEC isolates were negative for MCR genes, a finding that suggests "a very low probability" that MCR genes are prevalent in STEC recovered from the region. The authors say the findings also indicate a lower prevalence of transferable colistin resistance in the United States when compared with other countries, especially those where colistin use in food-producing animals has been uncontrolled.
Nov 8 PLoS One study

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