Acquisition of antimicrobial-resistant bacteria in the absence of antimicrobial exposure: A systematic review and meta-analysis

Gut colonization with multidrug resistant organisms in the intensive care unit: a systematic review and meta-analysis

BACKGROUND

Gut colonization with multidrug-resistant organisms (MDRO) frequently precedes infection among patients in the intensive care unit (ICU), although the dynamics of colonization are not completely understood. We performed a systematic review and meta-analysis of ICU studies which described the cumulative incidence and rates of MDRO gut acquisition.

METHODS

We systematically searched PubMed, Embase, and Web of Science for studies published from 2010 to 2023 reporting on gut acquisition of MDRO in the ICU. MDRO were defined as multidrug resistant non-Pseudomonas Gram-negative bacteria (NP-GN), Pseudomonas spp., and vancomycin-resistant Enterococcus (VRE). We included observational studies which obtained perianal or rectal swabs at ICU admission (within 48 h) and at one or more subsequent timepoints. Our primary outcome was the incidence rate of gut acquisition of MDRO, defined as any MDRO newly detected after ICU admission (i.e., not present at baseline) for all patient-time at risk. The study was registered with PROSPERO, CRD42023481569.

RESULTS

Of 482 studies initially identified, 14 studies with 37,305 patients met criteria for inclusion. The pooled incidence of gut acquisition of MDRO during ICU hospitalization was 5% (range: 1-43%) with a pooled incidence rate of 12.2 (95% CI 8.1-18.6) per 1000 patient-days. Median time to acquisition ranged from 4 to 26 days after ICU admission. Results were similar for NP-GN and Pseudomonas spp., with insufficient data to assess VRE. Among six studies which provided sufficient data to perform curve fitting, there was a quasi-linear increase in gut MDRO colonization of 1.41% per day which was stable through 30 days of ICU hospitalization (R2 = 0.50, p < 0.01).

CONCLUSIONS

Acquisition of gut MDRO was common in the ICU and increases with days spent in ICU through 30 days of follow-up. These data may guide future interventions seeking to prevent gut acquisition of MDRO in the ICU.

Difference between days of therapy and days of antibiotic spectrum coverage in an inpatient antimicrobial stewardship program: Vector autoregressive models for time-series analysis

OBJECTIVE

The days of therapy (DOT) metric, used to estimate antimicrobial consumption, has some limitations. Days of antibiotic spectrum coverage (DASC), a novel metric, overcomes these limitations. We examined the difference between these 2 metrics of inpatient intravenous antimicrobial consumption in assessing antimicrobial stewardship efficacy and antimicrobial resistance using vector autoregressive (VAR) models with time-series analysis.

METHODS

Differences between DOT and DASC were investigated at a tertiary-care center over 8 years using VAR models with 3 variables in the following order: (1) the monthly proportion of prospective audit and feedback (PAF) acceptance as an index of antimicrobial stewardship efficacy; (2) monthly DOT and DASC adjusted by 1,000 days present as indices of antimicrobial consumption; and (3) the monthly incidence of 5 organisms as an index of antimicrobial resistance.

RESULTS

The Granger causality test, which evaluates whether incorporating lagged variables can help predict other variables, showed that PAF activity contributed to DOT and DASC, which, in turn, contributed to the incidence of drug-resistant P. aeruginosa. Notably, only DASC helped predict the incidence of drug-resistant Enterobacterales. Another VAR analysis demonstrated that a high proportion of PAF acceptance was accompanied by decreased DASC in a given month, whereas increased DASC was accompanied by an increased incidence of drug-resistant Enterobacterales, unlike with DOT.

CONCLUSIONS

The VAR models of PAF activity, antimicrobial consumption, and antimicrobial resistance suggested that DASC may more accurately reflect the impact of PAF on antimicrobial consumption and be superior to DOT for predicting the incidence of drug-resistant Enterobacterales.

Opioid exposure as a potential risk factor for vancomycin-resistant enterococci colonization in the absence of antimicrobial exposure

BACKGROUND

Antimicrobial exposure leads to an increased risk of colonization and spread of vancomycin-resistant enterococci. Studies have also implicated exposure to nonantimicrobial medications as a potential risk factor for an increased risk of colonization with these pathogens.

METHODS

A matched case-control study was performed to determine specific nonantimicrobial medications associated with vancomycin-resistant enterococci rectal colonization. Cases and controls were defined as persons who were not exposed to antimicrobials in the preceding 12 months and in whom vancomycin-resistant enterococci rectal colonization was and was not detected at hospital admission, respectively. Matching was performed by the date of admission. Data were extracted from electronic medical records and included patient demographics, clinical data, and exposure to non-antimicrobial medications in the preceding 90 days.

RESULTS

Vancomycin-resistant enterococci colonization was identified among 2,919 (4.8%) patients during their first admission among 59,986 admissions. Among these patients, 27 cases were identified and were matched to 63 controls. Exposure to opioids was the only independent risk factor associated with colonization (adjusted odds ratio 3.8 [95% confidence interval 1.4-10.8], P-value = .01).

CONCLUSIONS

Opioid exposure may increase the risk of vancomycin-resistant enterococci colonization. Preventing the acquisition of these pathogens may require infection-prevention efforts targeting persons exposed to opioids.

Identifying global research gaps to mitigate antimicrobial resistance: A scoping review

OBJECTIVE

Identify research gaps relevant to the global effort to combat antimicrobial resistance.

METHODS

Web of Science, PubMed, Scopus, and Ovid MEDLINE were searched for reviews on antimicrobial resistance published between January 1, 2015 and December 31, 2019. Recommendations for future research were identified.

FINDINGS

Seventy-four reviews met inclusion criteria; 300 research gaps and recommendations were identified. The largest number were from the human health sector (105; 35%) followed by environmental health (72; 23%), animal health (66; 22%), food and feed (14; 5%), and plants and crops (8; 3%); 35 (12%) involved more than one sector. The largest number of gaps concerned surveillance of resistance (68; 23%), followed by study design or methodology (52; 17%), interventions (41; 14%), risk assessment and modeling (35; 12%), ecological (26; 9%) and biochemical (28; 9%) aspects of resistance, interface between reservoirs of resistant pathogens (24; 8%), and economic (15; 5%) and awareness- and behavior-related (11; 4%) aspects of antimicrobial resistance.

CONCLUSIONS

Important research gaps remain in our complete understanding of antimicrobial resistance, and more research is needed about its development, transmission, and impact across the interface of human, animal, and environmental reservoirs.