Infection control measures to decrease the burden of antimicrobial resistance in the critical care setting

Carbapenem-resistant Gram-negative bacteria (CR-GNB) in ICUs: resistance genes, therapeutics, and prevention - a comprehensive review

Intensive care units (ICUs) are specialized environments dedicated to the management of critically ill patients, who are particularly susceptible to drug-resistant bacteria. Among these, carbapenem-resistant Gram-negative bacteria (CR-GNB) pose a significant threat endangering the lives of ICU patients. Carbapenemase production is a key resistance mechanism in CR-GNB, with the transfer of resistance genes contributing to the extensive emergence of antimicrobial resistance (AMR). CR-GNB infections are widespread in ICUs, highlighting an urgent need for prevention and control measures to reduce mortality rates associated with CR-GNB transmission or infection. This review provides an overview of key aspects surrounding CR-GNB within ICUs. We examine the mechanisms of bacterial drug resistance, the resistance genes that frequently occur with CR-GNB infections in ICU, and the therapeutic options against carbapenemase genotypes. Additionally, we highlight crucial preventive measures to impede the transmission and spread of CR-GNB within ICUs, along with reviewing the advances made in the field of clinical predictive modeling research, which hold excellent potential for practical application.

Predictors of bacteremia and death, including immune status, in a large single-center cohort of unvaccinated ICU patients with COVID-19 pneumonia

BACKGROUND

We investigated the possible role of the immune profile at ICU admission, among other well characterized clinical and laboratory predictors of unfavorable outcome in COVID-19 patients assisted in ICU.

METHODS

Retrospective analysis of clinical and laboratory data collected for all consecutive patients admitted to the ICUs of the General Hospital of Pescara (Abruzzo, Italy), between 1^st March 2020 and 30^th April 2021, with a confirmed diagnosis of COVID-19 respiratory failure. Logistic regressions were used to identify independent predictors of bacteremia and mortality.

RESULTS

Out of 431 patients included in the study, bacteremia was present in N = 191 (44.3%) and death occurred in N = 210 (48.7%). After multivariate analysis, increased risk of bacteremia was found for viral reactivation (OR = 3.28; 95% CI:1.83-6.08), pronation (3.36; 2.12-5.37) and orotracheal intubation (2.51; 1.58-4.02). Increased mortality was found for bacteremia (2.05; 1.31-3.22), viral reactivation (2.29; 1.29-4.19) and lymphocytes < 0.6 × 10³c/µL (2.32; 1.49-3.64).

CONCLUSIONS

We found that viral reactivation, mostly due to Herpesviridae, was associated with increased risk of both bacteremia and mortality. In addition, pronation and intubation are strong predictors of bacteremia, which in turn together with severe lymphocytopenia due to SARS-CoV2 was associated with increased mortality. Most episodes of bacteremia, even due to Acinetobacter spp, were not predicted by microbiological evidence of colonization.

Associated deaths and disability-adjusted life-years caused by infections with antibiotic-resistant bacteria in Switzerland, 2010 to 2019

BackgroundCassini et al. (2019) estimated that, in 2015, infections with 16 different antibiotic-resistant bacteria resulted in ca 170 disability-adjusted life-years (DALYs) per 100,000 population in the European Union and European Economic area (EU/EEA). The corresponding estimate for Switzerland was about half of this (87.8 DALYs per 100,000 population) but still higher than that of several EU/EEA countries (e.g. neighbouring Austria (77.2)).AimIn this study, the burden caused by the same infections due to antibiotic-resistant bacteria ('AMR burden') in Switzerland from 2010 to 2019 was estimated and the effect of the factors 'linguistic region' and 'hospital type' on this estimate was examined.MethodsNumber of infections, DALYs and deaths were estimated according to Cassini et al. (2019) whereas separate models were built for each linguistic region/hospital type combination.ResultsDALYs increased significantly from 3,995 (95% uncertainty interval (UI): 3;327-4,805) in 2010 to 6,805 (95% UI: 5,820-7,949) in 2019. Linguistic region and hospital type stratifications significantly affected the absolute values and the slope of the total AMR burden estimates. DALYs per population were higher in the Latin part of Switzerland (98 DALYs per 100,000 population; 95% UI: 83-115) compared with the German part (57 DALYs per 100,000 population; 95% UI: 49-66) and in university hospitals (165 DALYs per 100,000 hospitalisation days; 95% UI: 140-194) compared with non-university hospitals (62 DALYs per 100,000 hospitalisation days; 95% UI: 53-72).ConclusionsThe AMR burden estimate in Switzerland has increased significantly between 2010 and 2019. Considerable differences depending on the linguistic region and the hospital type were identified - a finding which affects the nationwide burden estimation.

Impact of multicenter unified enhanced environmental cleaning and disinfection measures on nosocomial infections among patients in intensive care units

Objectives

Most Chinese hospitals have customized environmental cleaning policies and systems, with limited data availability based on evidence-based medicine. This study investigated the relationship between multidrug-resistant organism (MDRO) colonization in intensive care unit (ICU) patients and ICU surface bacterial contamination status.

Methods

This cross-sectional study comprised MDRO screening in ICU patients using bacterial cultivation by chromogenic medium; samples were collected before (control group) and after implementation of enhanced cleaning (cleaning group). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to identify and analyze microorganisms; the relationships of MDRO colonization with infection and environmental bacteria were analyzed.

Results

In total, 196 patients were enrolled in the study (104 and 92 in control and cleaning groups, respectively); 1042 MDROs were subjected to screening before and after cleaning. After cleaning, the rate of MDRO detection on surfaces of frequently touched objects in ICUs decreased from 31.77% to 13.32%. There were fewer MDRO homologues in the cleaning group than in the control group. Moreover, the cleaning group had a shorter ICU stay and significantly lower mortality rate.

Conclusions

Enhanced environmental cleaning and disinfection could reduce environmental MDRO accumulation and suppress MDRO colonization in ICUs, thereby reducing nosocomial infections and improving adverse patient outcomes.

Control of Gram-negative multi-drug resistant microorganisms in an Italian ICU: Rapid decline as a result of a multifaceted intervention, including conservative use of antibiotics

BACKGROUND

Gram-negative Multi-Drug-Resistant Organisms (GNMDROs) cause an increasing burden of disease in Intensive Care Units (ICUs). We deployed a multifaceted intervention to control selection and transmission of GNMDROs and to estimate at which rate GNMDROs would decline with our interventional bundle.

METHODS

Interventions implemented in 2015: in-ward Antimicrobial-Stewardship-Program for appropriate management of antimicrobial prescription; infection monitoring with nasal/rectal swabs and repeated procalcitonin assays; 24 h microbiological support (since 2016); prevention of catheter-related infections, VAPs and in-ward GNMDROs transmission; education of ICU personnel. In May 2017, epidemiological, clinical and microbiological data were collected and retrospectively analyzed. Rates of resistance in Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii, as well as percentages of resistance among all Gram-negative bacteria were compared during the study period.

RESULTS

Of 668 patients, at least one isolate was obtained from 399 patients. The proportions of patients with infection and with Gram-negative isolates were even across the 5 semesters (p = 0.8). For Klebsiella pneumoniae, the number of strains resistant to carbapenems fell from 94% to 6% (p < 0.001). Significant drops were also observed for Pseudomonas aeruginosa and Acinetobacter baumannii. Percentages of resistance for all Gram-negative isolates fell from 91% to 13% (p < 0.0001). The reduction in antibiotic prescription translated in a considerable reduction of pharmacy costs. Multivariate models confirmed that the hospitalization semester was the most relevant independent predictor of resistance among Gram-negative bacteria.

CONCLUSIONS

Our experience provides further evidence that a multi-faceted intervention, aimed to reduce selection and transmission of GNMDROs with efficient microbiological support, may yield remarkable results in a short time interval.

Daily bathing strategies and cross-transmission of multidrug-resistant organisms: Impact of chlorhexidine-impregnated wipes in a multidrug-resistant gram-negative bacteria endemic intensive care unit

BACKGROUND

Health-care associated infections are a major cause of morbidity and mortality in critical care units. The aim of this study is to evaluate the effectiveness of chlorhexidine gluconate (CHG)-impregnated wipes in the daily bathing of patients in an intensive care unit (ICU) to prevent cross-transmission and colonization by multidrug-resistant organisms (MDROs) METHODS: Prospective cohort study with an intervention of 11 months. The intervention consisted of using CHG-impregnated wipes for the daily bathing of patients on mechanical ventilation or colonized by MDROs. Monthly trends in the number of patients colonized by MDROs and the incidence of nosocomial infections were evaluated.

RESULTS

A total of 1,675 patients were admitted to the unit during the intervention period, and 430 (25.7%) were bathed with chlorhexidine wipes. A significant decrease was observed in the incidence of colonization by MDROs over the months (β = -0.209; r² = 0.549; P = .027), and in the number of patients colonized compared with the equivalent period of the previous year (22.0% vs 18.4%; P = .01). No significant decrease was observed in the incidence of nosocomial infection between the two periods (4.11% vs 4.57%; P = .355). No dermatologic problems were observed in the treated patients.

CONCLUSIONS

The use of CHG-impregnated wipes reduces cross-transmission and colonization by MDROs in the ICUs in an endemic situation because of multidrug-resistant Enterobacteriaceae.

Efficacy of an ethanol/guar/triclosan/glycerine gel on bacteria and yeast loads in canine pododermatitis: a pilot study

OBJECTIVES

To assess efficacy of a gel compound containing guar, glycerine, triclosan and ethanol (Pawcare®, JOKER Technologies, Kerzers, Switzerland) in decreasing bacterial and yeast loads on the paws of dogs with erythematous, greasy and/or malodorous pododermatitis.

METHODS

In 20 dogs, each with at least two affected paws, semiquantitative Malassezia species counts were performed on 10 oil-immersion fields (range: 0 to 30) from acetate tapes pressed on the palmar/plantar surface of one paw. Half of the area was sampled before and the other half immediately after the application of Pawcare(®) . With a similar procedure, swab samples were collected from the other paw for bacterial culture, identification and evaluation of colony-forming units before and immediately after treatment. Statistical evaluation of pre- and posttreatment counts was performed with the Wilcoxon signed-rank test.

RESULTS

Nine dogs were positive for Malassezia species Mean acetate tape preparation counts decreased significantly from 8·78 (±8·03) to 5·668 (±6·65) (P=0·0039) after treatment. Twenty-five bacterial isolates of 11 different species were cultured in 19 dogs. Posttreatment cultures were sterile in 8 dogs that had an initial zero or low number (1 to 2 log counts) of colony-forming units. In cases with a higher pre-treatment number of colony forming units (2 to 6 log counts), there was a significant decrease - by a mean of 1·16 log counts (pre 3·12 ±1·69, post 1·96 ±1·57) (P=0·0002).

CLINICAL SIGNIFICANCE

The findings of the present study support the use of PawCare® gel to decrease bacterial and yeast loads in dogs affected by chronic diseases involving the inter-digital spaces.

Surveillance cultures growing carbapenem-Resistant Acinetobacter baumannii predict the development of clinical infections: a retrospective cohort study

BACKGROUND

We aimed to determine the effect of the presence of carbapenem-resistant Acinetobacter baumannii in accordance with surveillance cultures on the subsequent development of clinical infections by this organism.

METHODS

This retrospective cohort study was conducted at a tertiary hospital from January 2010 to November 2011. We included all consecutive patients admitted to the trauma intensive care unit, who had weekly surveillance cultures performed (from rectum, and if intubated, respiratory secretions), and without evidence of A. baumannii infections prior to the collection of the first surveillance culture. Univariable and multivariable analyses were performed using log-binomial regression. Survival analyses were performed using Cox proportional hazards.

RESULTS

Three hundred sixty-four patients were included, of whom 49 (13.5%) had carbapenem-resistant A. baumannii on surveillance cultures. Patients with positive surveillance cultures had 8.4 (95% confidence interval [CI], 5.6-12.7; P < .0001) times the risk of developing a subsequent A. baumannii infection compared with patients who remained negative on surveillance cultures. Multivariable analysis showed significant associations between clinical infection and both positive surveillance cultures (relative risk [RR], 5.9 [95% CI, 3.8-9.3]; P < .0001) and mechanical ventilation (RR, 4.3 [95% CI, 1.03-18.2]; P = .05). On survival analyses, the only variable associated with the development of clinical infections was the presence of positive surveillance cultures (hazard ratio, 16.3 [95% CI, 9.1-29.1]; P < .001).

CONCLUSIONS

Presence of carbapenem-resistant A. baumannii on surveillance cultures is strongly associated with subsequent development of carbapenem-resistant A. baumannii infections. Prevention efforts should be focused at limiting the acquisition of this organism during hospitalization.

Optimizing antimicrobial therapy in critically ill patients

Critically ill patients with infection in the intensive care unit (ICU) would certainly benefit from timely bacterial identification and effective antimicrobial treatment. Diagnostic techniques have clearly improved in the last years and allow earlier identification of bacterial strains in some cases, but these techniques are still quite expensive and not readily available in all institutions. Moreover, the ever increasing rates of resistance to antimicrobials, especially in Gram-negative pathogens, are threatening the outcome for such patients because of the lack of effective medical treatment; ICU physicians are therefore resorting to combination therapies to overcome resistance, with the direct consequence of promoting further resistance. A more appropriate use of available antimicrobials in the ICU should be pursued, and adjustments in doses and dosing through pharmacokinetics and pharmacodynamics have recently shown promising results in improving outcomes and reducing antimicrobial resistance. The aim of multidisciplinary antimicrobial stewardship programs is to improve antimicrobial prescription, and in this review we analyze the available experiences of such programs carried out in ICUs, with emphasis on results, challenges, and pitfalls. Any effective intervention aimed at improving antibiotic usage in ICUs must be brought about at the present time; otherwise, we will face the challenge of intractable infections in critically ill patients in the near future.