Screening for Intestinal Carriage of Extended-spectrum Beta-lactamase-producing Enterobacteriaceae in Critically Ill Patients: Expected Benefits and Evidence-based Controversies

Prediction models for diagnosis and prognosis of the colonization or infection of multidrug-resistant organisms in adults: a systematic review, critical appraisal, and meta-analysis

BACKGROUND

Prediction models help to target patients at risk of multidrug-resistant organism (MDRO) colonization or infection and could serve as tools informing clinical practices to prevent MDRO transmission and inappropriate empiric antibiotic therapy. However, there is limited evidence to identify which among the available models are of low risk of bias and suitable for clinical application.

OBJECTIVES

To identify, describe, appraise, and summarise the performance of all prognostic and diagnostic models developed or validated for predicting MDRO colonization or infection.

DATA SOURCES

Six electronic literature databases and clinical registration databases were searched until April 2022.

STUDY ELIGIBILITY CRITERIA

Development and validation studies of any multivariable prognostic and diagnostic models to predict MDRO colonization or infection in adults.

PARTICIPANTS

Adults (≥ 18 years old) without MDRO colonization or infection (in prognostic models) or with unknown or suspected MDRO colonization or infection (in diagnostic models).

ASSESSMENT OF RISK OF BIAS

The Prediction Model Risk of Bias Assessment Tool was used to assess the risk of bias. Evidence certainty was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach.

METHODS OF DATA SYNTHESIS

Meta-analyses were conducted to summarize the discrimination and calibration of the models' external validations conducted in at least two non-overlapping datasets.

RESULTS

We included 162 models (108 studies) developed for diagnosing (n = 135) and predicting (n = 27) MDRO colonization or infection. Models exhibited a high-risk of bias, especially in statistical analysis. High-frequency predictors were age, recent invasive procedures, antibiotic usage, and prior hospitalization. Less than 25% of the models underwent external validations, with only seven by independent teams. Meta-analyses for one diagnostic and two prognostic models only produced very low to low certainty of evidence.

CONCLUSIONS

The review comprehensively described the models for identifying patients at risk of MDRO colonization or infection. We cannot recommend which models are ready for application because of the high-risk of bias, limited validations, and low certainty of evidence from meta-analyses, indicating a clear need to improve the conducting and reporting of model development and external validation studies to facilitate clinical application.

Risk factors for colonisation by Multidrug-Resistant bacteria in critical care units

INTRODUCTION

Antimicrobial resistance is a major public health challenge recognised by the WHO as an urgent global healthcare concern. Patients in Intensive Care Units (ICUs) are particularly prone to colonisation and/or infection by multidrug-resistant organisms (MDROs).

OBJECTIVES

Delineate the epidemiological characteristics and risk factors for MDROs colonisation in mixed ICUs and Resuscitation Units by focusing on initial and nosocomial colonisation.

MATERIAL AND METHODS

A descriptive observational study with analytical elements. It uses the Zero-Resistance register from the Preventive Medicine Service of the Albacete General University Hospital (Spain) from April 2016 to December 2021. It identifies the risk factors for MDROs colonisation.

RESULTS

Of 7,541 cases, 61.0 % with initial colonisation had risk factors for MDROs versus 34.0 % not colonised upon hospitalisation (p < 0.001). Significant risk factors for initial colonisation included hospitalisation for ≥ 5 days within the last 3 months, prior MDROs colonisation/infection and institutionalization. No significant risk factor differences were found for nosocomial colonisation. An association between longer ICU stays and nosocomial colonisation (p < 0.001) was noted.

CONCLUSIONS

Significant risk factors for initial MDROs colonisation were hospitalisation for ≥ 5 days in the last 3 months, prior MDROs colonisation/infection and institutionalisation. Longer ICU stays increased the nosocomial colonisation risk.

IMPLICATIONS FOR CLINICAL PRACTICE

This study underscores the importance to early identify and manage patients at risk for MDROs colonisation in ICUs. By recognising factors (i.e. previous hospitalisations, existing colonisation or infection, impact of prolonged ICU stay), healthcare providers can implement targeted strategies to mitigate the spread of MDROs; e.g. enhanced surveillance, stringent infection control measures and judicious antibiotics use. Our findings highlight the need for a comprehensive approach to manage antimicrobial resistance in critical care settings to ultimately improve patient outcomes and reduce MDROs burden in hospitals.

Significance of colonization by antibiotic-resistant organisms prior to congenital heart disease surgery in children from low- to middle-income countries sent by non-governmental organizations to Switzerland

PURPOSE

Children with congenital heart disease (CHD) from low- to middle-income countries (LMIC) are suspected to have a high prevalence of antibiotic-resistant microorganisms (ARMOs) carriage, but data are currently lacking. Carriage of ARMOs could impact the post-operative course in pediatric intensive care unit (PICU). The aim of the study was to assess the prevalence of ARMOs carriage in children with CHD from LMIC and its impact on post-operative outcomes.

METHODS

This was a retrospective monocentric study from 01/2019 to 12/2022. Included patients were children (0-18 years) from a LMIC admitted after CHD surgery and with AMRO screening performed the week before. Infections and post-operative evolution were compared based on ARMOs carriage status.

FINDINGS

Among 224 surgeries (median age 38.5 months (IQR 22-85.5)), ARMOs carriage was evidenced in 95 cases (42.4%). Main organisms isolated were Extended Spectrum Beta-Lactamase (ESBL) producing E. coli (75/224) 33.5%)) and ESBL-K. pneumoniae (30/224) 13.4%)). Median mechanical ventilation duration was 1 day (IQR 0-1), PICU stay 3 days (IQR 2-4) and hospital stay 6.5 days (IQR 5-10). A total of 17 infectious episodes occurred in 15 patients, mostly consisting in hospital-acquired pneumonia (HAP) (12/17). Only two infections were caused by a colonizing ARMO. Occurrence of infections and patients' outcome were similar between ARMO carriers and non-carriers. Higher use of carbapenems (6 (6.3%) vs 1 (0.8%), p = 0.04) and a trend to a higher use of vancomycin (14 (13.7%) vs 9 (6.9%), p = 0.04) in case of ARMOs carriage. Applying current guidelines, negative swab screening could have led to sparing most of empirical vancomycin therapy (11/12) for HAP based on current guidelines.

CONCLUSION

Prevalence of AMROs carriage is high in children from LMIC and has a limited impact on patients' outcome. However, ARMOs carriage leads to higher consumption of antibiotics. Screening may help saving use of broad-spectrum antibiotic in non-carrier patients.

Prevalence and risk factors for colonisation and infection with carbapenem-resistant Enterobacterales in intensive care units: A prospective multicentre study

OBJECTIVES

This study aimed to investigate the prevalence and risk factors for carbapenem-resistant Enterobacterales colonisation/infection at admission and acquisition among patients admitted to the intensive care unit.

RESEARCH METHODOLOGY/DESIGN

A prospective and multicentre study.

SETTING

This study was conducted in 24 intensive care units in Anhui, China.

MAIN OUTCOME MEASURES

Demographic and clinical data were collected, and rectal carbapenem-resistant Enterobacterales colonisation was detected by active screening. Multivariate logistic regression models were used to analyse factors associated with colonisation/infection with carbapenem-resistant Enterobacterales at admission and acquisition during the intensive care unit stay.

RESULTS

There were 1133 intensive care unit patients included in this study. In total, 5.9% of patients with carbapenem-resistant Enterobacterales colonisation/infection at admission, and of which 56.7% were colonisations. Besides, 8.5% of patients acquired carbapenem-resistant Enterobacterales colonisation/infection during the intensive care stay, and of which 67.6% were colonisations. At admission, transfer from another hospital, admission to an intensive care unit within one year, colonisation/infection/epidemiological link with carbapenem-resistant Enterobacterales within one year, and exposure to any antibiotics within three months were risk factors for colonisation/infection with carbapenem-resistant Enterobacterales. During the intensive care stay, renal disease, an epidemiological link with carbapenem-resistant Enterobacterales, exposure to carbapenems and beta-lactams/beta-lactamase inhibitors, and intensive care stay of three weeks or longer were associated with acquisition.

CONCLUSION

The prevalence of colonisation/infection with carbapenem-resistant Enterobacterales in intensive care units is of great concern and should be monitored systematically. Particularly for the 8.5% prevalence of carbapenem-resistant Enterobacterales acquisition during the intensive care stay needs enhanced infection prevention and control measures in these setting. Surveillance of colonisation/infection with carbapenem-resistant Enterobacterales at admission and during the patient's stay represents an early identification tool to prevent further transmission of carbapenem-resistant Enterobacterales.

IMPLICATIONS FOR CLINICAL PRACTICE

Carbapenem-resistant Enterobacterales colonization screening at admission and during the patient's stay is an important tool to control carbapenem-resistant Enterobacterales spread in intensive care units.

Preventive isolation criteria for the detection of multidrug-resistant bacteria in patients admitted to the Intensive Care Unit: A multicenter study within the Zero Resistance program

OBJECTIVE

To verify the validity of a checklist of risk factors (RFs) proposed by the Spanish "Zero Resistance" project (ZR) in the detection of multidrug-resistant bacteria (MRB), and to identify other possible RFs for colonization and infection by MRB on admission to the Intensive Care Unit (ICU).

DESIGN

A prospective cohort study, conducted in 2016.

SETTING

Multicenter study, patients requiring admission to adult ICUs that applied the ZR protocol and accepted the invitation for participating in the study.

PATIENTS OR PARTICIPANTS

Consecutive sample of patients admitted to the ICU and who underwent surveillance (nasal, pharyngeal, axillary and rectal) or clinical cultures.

INTERVENTIONS

Analysis of the RFs of the ZR project, in addition to other comorbidities, included in the ENVIN registry. A univariate and multivariate analysis was performed, with binary logistic regression methodology (significance considered for p < 0.05). Sensitivity and specificity analyses were performed for each of the selected factors.

MAIN VARIABLES OF INTEREST

Carrier of MRB on admission to the ICU, RFs (previous MRB colonization/infection, hospital admission in the previous 3 months, antibiotic use in the past month, institutionalization, dialysis, and other chronic conditions) and comorbidities.

RESULTS

A total of 2270 patients from 9 Spanish ICUs were included. We identified MRB in 288 (12.6% of the total patients admitted). In turn, 193 (68.2%) had some RF (OR 4.6, 95%CI: 3.5-6.0). All 6 RFs from the checklist reached statistical significance in the univariate analysis (sensitivity 66%, specificity 79%). Immunosuppression, antibiotic use on admission to the ICU and the male gender were additional RFs for MRB. MRB were isolated in 87 patients without RF (31.8%).

CONCLUSIONS

Patients with at least one RF had an increased risk of being carriers of MRB. However, almost 32% of the MRB were isolated in patients without RFs. Other comorbidities such as immunosuppression, antibiotic use on admission to the ICU and the male gender could be considered as additional RFs.

Quantification of time delay between screening and subsequent initiation of contact isolation for carriers of extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales: A post hoc subgroup analysis of the R-GNOSIS WP5 Trial

OBJECTIVES

The aim of this study was to quantify the time delay between screening and initiation of contact isolation for carriers of extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (ESBL-E).

METHODS

This study was a secondary analysis of contact isolation periods in a cluster-randomized controlled trial that compared 2 strategies to control ESBL-E (trial no. ISRCTN57648070). Patients admitted to 20 non-ICU wards in Germany, the Netherlands, Spain, and Switzerland were screened for ESBL-E carriage on admission, weekly thereafter, and on discharge. Data collection included the day of sampling, the day the wards were notified of the result, and subsequent ESBL-E isolation days.

RESULTS

Between January 2014 and August 2016, 19,122 patients, with a length of stay ≥2 days were included. At least 1 culture was collected for 16,091 patients (84%), with a median duration between the admission day and the day of first sample collection of 2 days (interquartile range [IQR], 1-3). Moreover, 854 (41%) of all 2,078 ESBL-E carriers remained without isolation during their hospital stay. In total, 6,040 ESBL-E days (32% of all ESBL-E days) accrued for patients who were not isolated. Of 2,078 ESBL-E-carriers, 1,478 ESBL-E carriers (71%) had no previous history of ESBL-E carriage. Also, 697 (34%) were placed in contact isolation with a delay of 4 days (IQR, 2-5), accounting for 2,723 nonisolation days (15% of ESBL-E days).

CONCLUSIONS

Even with extensive surveillance screening, almost one-third of all ESBL-E days were nonisolation days. Limitations in routine culture-based ESBL-E detection impeded timely and exhaustive implementation of targeted contact isolation.

Ventilator-Associated Pneumonia in COVID-19 Patients Admitted in Intensive Care Units: Relapse, Therapeutic Failure and Attributable Mortality-A Multicentric Observational Study from the OutcomeRea Network

Introduction: Ventilator-associated pneumonia (VAP) incidence is high among critically ill COVID-19 patients. Its attributable mortality remains underestimated, especially for unresolved episodes. Indeed, the impact of therapeutic failures and the determinants that potentially affect mortality are poorly evaluated. We assessed the prognosis of VAP in severe COVID-19 cases and the impact of relapse, superinfection, and treatment failure on 60-day mortality. Methods: We evaluated the incidence of VAP in a multicenter prospective cohort that included adult patients with severe COVID-19, who required mechanical ventilation for ≥48 h between March 2020 and June 2021. We investigated the risk factors for 30-day and 60-day mortality, and the factors associated with relapse, superinfection, and treatment failure. Results: Among 1424 patients admitted to eleven centers, 540 were invasively ventilated for 48 h or more, and 231 had VAP episodes, which were caused by Enterobacterales (49.8%), P. aeruginosa (24.8%), and S. aureus (22%). The VAP incidence rate was 45.6/1000 ventilator days, and the cumulative incidence at Day 30 was 60%. VAP increased the duration of mechanical ventilation without modifying the crude 60-day death rate (47.6% vs. 44.7% without VAP) and resulted in a 36% increase in death hazard. Late-onset pneumonia represented 179 episodes (78.2%) and was responsible for a 56% increase in death hazard. The cumulative incidence rates of relapse and superinfection were 45% and 39.5%, respectively, but did not impact death hazard. Superinfection was more frequently related to ECMO and first episode of VAP caused by non-fermenting bacteria. The risk factors for treatment failure were an absence of highly susceptible microorganisms and vasopressor need at VAP onset. Conclusions: The incidence of VAP, mainly late-onset episodes, is high in COVID-19 patients and associated with an increased risk of death, similar to that observed in other mechanically ventilated patients. The high rate of VAP due to difficult-to-treat microorganisms, pharmacokinetic alterations induced by renal replacement therapy, shock, and ECMO likely explains the high cumulative risk of relapse, superinfection, and treatment failure.

Relationship between immunosuppression and intensive care unit-acquired colonization and infection related to multidrug-resistant bacteria: a prospective multicenter cohort study

PURPOSE

The impact of immunosuppression on intensive care unit (ICU)-acquired colonization and infection related to multidrug-resistant (MDR) bacteria (ICU-MDR-col and ICU-MDR-inf, respectively) is unknown.

METHODS

We carried out an observational prospective cohort study in 8 ICUs in France (all with single-bed rooms and similar organizational characteristics). All consecutive patients with an ICU stay > 48 h were included, regardless of immune status, and followed for 28 days. Patients underwent systematic screening for colonization with MDR bacteria upon admission and every week subsequently. Immunosuppression was defined as active cancer or hematologic malignancy, neutropenia, solid-organ transplant, use of steroids or immunosuppressive drugs, human immunodeficiency virus infection and genetic. The primary endpoint was the incidence rate of a composite outcome including ICU-MDR-col and/or ICU-MDR-inf.

RESULTS

750 patients (65.9% males, median age 65 years) were included, among whom 264 (35.2%) were immunocompromised. Reasons for ICU admission, severity scores and exposure to invasive devices and antibiotics during ICU stay were comparable between groups. After adjustment for center and pre-specified baseline confounders, immunocompromised patients had a lower incidence rate of ICU-MDR-col and/or ICU-MDR-inf (adjusted incidence ratio 0.68, 95% CI 0.52-0.91). When considered separately, the difference was significant for ICU-MDR-col, but not for ICU-MDR-inf. The distribution of MDR bacteria was comparable between groups, with a majority of Enterobacteriacae resistant to third-generation cephalosporins (~ 74%).

CONCLUSION

Immunocompromised patients had a significantly lower incidence rate of a composite outcome including ICU-MDR-col and/or ICU-MDR-inf. This finding points to the role of contact precautions and isolation measures, and could have important implications on antibiotic stewardship in this population.

Impact of Antibiotic Consumption on the Acquisition of Extended-Spectrum β-Lactamase Producing Enterobacterales Carriage during the COVID-19 Crisis in French Guiana

(1) Background: During the COVID-19 outbreak, several studies showed an increased prevalence of extended-spectrum β-lactamase producing Enterobacterales (ESBL-PE) carriage in intensive care units (ICUs). Our objective was to assess the impact of antibiotic prescriptions on the acquisition of ESBL-PE in ICUs during the COVID-19 crisis. (2) Methods: We conducted an observational study between 1 April 2020, and 31 December 2021, in the medical-surgical ICU of the Cayenne General Hospital. We defined two periods: Period 1 with routine, empirical antibiotic use, and Period 2 with no systematic empiric antibiotic prescription. (3) Results: ICU-acquired ESBL-PE carriage was 22.8% during Period 1 and 9.4% during Period 2 (p = 0.005). The main isolated ESBL-PE was Klebsiella pneumoniae (84.6% in Period 1 and 58.3% in Period 2). When using a generalized linear model with a Poisson family, exposure to cefotaxime was the only factor independently associated with ESBL-PE acquisition in ICU (p = 0.002, IRR 2.59 (95% IC 1.42-4.75)). The propensity scores matching estimated the increased risk for cefotaxime use to acquire ESBL-PE carriage at 0.096 (95% CI = 0.02-0.17), p = 0.01. (4) Conclusions: Exposure to cefotaxime in patients with severe COVID-19 is strongly associated with the emergence of ESBL-PE in the context of maximal infection control measures.

The role of the microbiology laboratory in the diagnosis of multidrug-resistant Gram-negative bacilli infections. The importance of the determination of resistance mechanisms

Early diagnosis and treatment has an important impact on the morbidity and mortality of infections caused by multidrug-resistant bacteria. Multidrug-resistant gram-negative bacilli (MR-GNB) constitute the main current threat in hospitals and especially in intensive care units (ICU). The role of the microbiology laboratory is essential in providing a rapid and effective response. This review updates the microbiology laboratory procedures for the rapid detection of BGN-MR and its resistance determinants. The role of the laboratory in the surveillance and control of outbreaks caused by these bacteria, including typing techniques, is also studied. The importance of providing standardized resistance maps that allow knowing the epidemiological situation of the different units is emphasized. Finally, the importance of effective communication systems for the transmission of results and decision making in the management of patients infected by BGN-MR is reviewed.

Healthcare-associated infections in adult intensive care unit patients: Changes in epidemiology, diagnosis, prevention and contributions of new technologies

Patients in intensive care units (ICUs) are at high risk for healthcare-acquired infections (HAI) due to the high prevalence of invasive procedures and devices, induced immunosuppression, comorbidity, frailty and increased age. Over the past decade we have seen a successful reduction in the incidence of HAI related to invasive procedures and devices. However, the rate of ICU-acquired infections remains high. Within this context, the ongoing emergence of new pathogens, further complicates treatment and threatens patient outcomes. Additionally, the SARS-CoV-2 (COVID-19) pandemic highlighted the challenge that an emerging pathogen provides in adapting prevention measures regarding both the risk of exposure to caregivers and the need to maintain quality of care. ICU nurses hold a special place in the prevention and management of HAI as they are involved in basic hygienic care, steering and implementing quality improvement initiatives, correct microbiological sampling, and aspects antibiotic stewardship. The emergence of more sensitive microbiological techniques and our increased knowledge about interactions between critically ill patients and their microbiota are leading us to rethink how we define HAIs and best strategies to diagnose, treat and prevent these infections in the ICU. This multidisciplinary expert review, focused on the ICU setting, will summarise the recent epidemiology of ICU-HAI, discuss the place of modern microbiological techniques in their diagnosis, review operational and epidemiological definitions and redefine the place of several controversial preventive measures including antimicrobial-impregnated medical devices, chlorhexidine-impregnated washcloths, catheter dressings and chlorhexidine-based mouthwashes. Finally, general guidance is suggested that may reduce HAI incidence and especially outbreaks in ICUs.

Empiric Treatment in HAP/VAP: “Don’t You Want to Take a Leap of Faith?”

Ventilator-associated pneumonia is a frequent cause of ICU-acquired infections. These infections are associated with high morbidity and mortality. The increase in antibiotic resistance, particularly among Gram-negative bacilli, makes the choice of empiric antibiotic therapy complex for physicians. Multidrug-resistant organisms (MDROs) related infections are associated with a high risk of initial therapeutic inadequacy. It is, therefore, necessary to quickly identify the bacterial species involved and their susceptibility to antibiotics. New diagnostic tools have recently been commercialized to assist in the management of these infections. Moreover, the recent enrichment of the therapeutic arsenal effective on Gram-negative bacilli raises the question of their place in the therapeutic management of these infections. Most national and international guidelines recommend limiting their use to microbiologically documented infections. However, many clinical situations and, in particular, the knowledge of digestive or respiratory carriage by MDROs should lead to the discussion of the use of these new molecules, especially the new combinations with beta-lactamase inhibitors in empirical therapy. In this review, we present the current epidemiological data, particularly in terms of MDRO, as well as the clinical and microbiological elements that may be taken into account in the discussion of empirical antibiotic therapy for patients managed for ventilator-associated pneumonia.

Behind Every Great Infection Prevention Program is a Great Microbiology Laboratory: Key Components and Strategies for an Effective Partnership

A great clinical microbiology laboratory supporting a great infection prevention program requires focusing on the following services: rapid and accurate identification of pathogens associated with health care-associated infections; asymptomatic surveillance for health care-acquired pathogens before infections arise; routine use of broad and flexible antimicrobial susceptibility testing to direct optimal therapy; implementation of epidemiologic tracking tools to identify outbreaks; development of clear result communication with interpretative comments for clinicians. These goals are best realized in a collaborative relationship with the infection prevention program so that both can benefit from the shared priorities of providing the best patient care.

Impact of a restrictive antibiotic policy on the acquisition of extended-spectrum beta-lactamase-producing Enterobacteriaceae in an endemic region: a before-and-after, propensity-matched cohort study in a Caribbean intensive care unit

BACKGROUND

High-level antibiotic consumption plays a critical role in the selection and spread of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) in the ICU. Implementation of a stewardship program including a restrictive antibiotic policy was evaluated with respect to ESBL-E acquisition (carriage and infection).

METHODS

We implemented a 2-year, before-and-after intervention study including all consecutive adult patients admitted for > 48 h in the medical-surgical 26-bed ICU of Guadeloupe University Hospital (French West Indies). A conventional strategy period (CSP) including a broad-spectrum antibiotic as initial empirical treatment, followed by de-escalation (period before), was compared to a restrictive strategy period (RSP) limiting broad-spectrum antibiotics and shortening their duration. Antibiotic therapy was delayed and initiated only after microbiological identification, except for septic shock, severe acute respiratory distress syndrome and meningitis (period after). A multivariate Cox proportional hazard regression model adjusted on propensity score values was performed. The main outcome was the median time of being ESBL-E-free in the ICU. Secondary outcome included all-cause ICU mortality.

RESULTS

The study included 1541 patients: 738 in the CSP and 803 in the RSP. During the RSP, less patients were treated with antibiotics (46.8% vs. 57.9%; p < 0.01), treatment duration was shorter (5 vs. 6 days; p < 0.01), and administration of antibiotics targeting anaerobic pathogens significantly decreased (65.3% vs. 33.5%; p < 0.01) compared to the CSP. The incidence of ICU-acquired ESBL-E was lower (12.1% vs. 19%; p < 0.01) during the RSP. The median time of being ESBL-E-free was 22 days (95% CI 16-NA) in the RSP and 18 days (95% CI 16-21) in the CSP. After propensity score weighting and adjusted analysis, the median time of being ESBL-E-free was independently associated with the RSP (hazard ratio, 0.746 [95% CI 0.575-0.968]; p = 0.02, and hazard ratio 0.751 [95% CI 0.578-0.977]; p = 0.03, respectively). All-cause ICU mortality was lower in the RSP than in the CSP (22.5% vs. 28.6%; p < 0.01).

CONCLUSIONS

Implementation of a program including a restrictive antibiotic strategy is feasible and is associated with less ESBL-E acquisition in the ICU without any worsening of patient outcome.

Evaluation of the performance of rapid tests for screening carriers of acquired ESBL-producing Enterobacterales and their impact on turnaround time

BACKGROUND

Extended-spectrum β-lactamase (ESBL)-producing Enterobacterales constitute a global burden for hospital infection, and the identification of carriers by screening patients at risk is recommended by several guidelines.

AIM

To evaluate the impact of rapid ESBL tests on the turnaround time (TAT) of screening.

METHODS

Rectal swabs were analysed by culture and synergism tests for identification of non-Esherichia coli Enterobacterales that produce ESBLs (NEcESBL-producing Enterobacterales). The Rapid ESBL NP and NG CTX-M MULTI tests were performed on colonies grown on chromogenic media. The results of polymerase chain reaction and sequencing of ESBL genes were used as the gold standard.

RESULTS

Among 473 analysed swabs, 75 (15.9%) grew NEcESBL-producing Enterobacterales, leading to 89 isolates. Sensitivities of the synergism, Rapid ESBL NP and NG CTX-M MULTI tests were 0.97 [95% confidence interval (CI) 0.88-0.99], 0.81 (95% CI 0.69-0.89) and 0.90 (95% CI 0.80-0.96), respectively. Specificities were 0.92 (95% CI 0.73-0.99), 0.85 (95% CI 0.64-0.95) and 0.96 (95% CI 0.78-1.00), respectively. Considering the 473 rectal swabs, ESBL screening using the synergism, Rapid ESBL NP and NG CTX-M MULTI tests was calculated. Sensitivities were 0.96 (95% CI 0.86-0.99), 0.81 (95% CI 0.68-0.90) and 0.91 (95% CI 0.79-0.97); specificities were 1.00 (95% CI 0.98-1.00), 0.99 (95% CI 0.98-1.00) and 1.00 (95% CI 0.99-1.00); positive predictive values were 0.96 (95% CI 0.86-0.99), 0.94 (95% CI 0.81-0.98) and 1.00 (95% CI 0.91-1.00); and negative predictive values were 1.00 (95% CI 0.98-1.00), 0.98 (95% CI 0.96-0.99) and 0.99 (95% CI 0.97-1.00), respectively. When no NEcESBL-producing Enterobacterales were observed, the mean TAT was 30 h. When NEcESBL-producing Enterobacterales were identified, the mean TATs were 74.7, 38.0 and 36.7 h for the synergism, Rapid ESBL NP and NG CTX-M MULTI tests, respectively.

CONCLUSION

The two rapid ESBL tests showed good performance and allowed a reduction in TAT for screening protocols to identify patients carrying ESBL-producing Enterobacterales.

Risk stratification for multidrug-resistant Gram-negative infections in ICU patients

PURPOSE OF REVIEW

Antimicrobial resistance among Gram-negative microorganisms has alarmingly increased in the past 10 years worldwide. Infections caused by these microorganisms are difficult to treat, especially in critically ill patients.The present review examines how to accurately predict which patients carry a greater risk of colonization or infection on which to base the timely choice of an effective empirical antibiotic treatment regimen and avoid antibiotic overuse.

RECENT FINDINGS

There are many risk factors for acquiring one of many multidrug-resistant Gram-negative microorganisms (MDR-GN); however, scores anticipating colonization, infection among those colonized, or mortality among those infected have a variable accuracy. Accuracy of scores anticipating colonization is low. Scores predicting infections among colonized patients are, in general, better, and ICU patients infected with MDR-GN have a worse prognosis than those infected by non-resistant microorganisms. Scores are, in general, better at excluding patients.

SUMMARY

Despite these limitations, scores continue to gain popularity including those by Giannella, Tumbarello, Johnson, or the scores INCREMENT carbapenem-producing Enterobacteriaceae score, Cano, Tartof, or CarbaSCORE.

Spontaneous decolonization during hospitalization in intensive care unit patients colonized by extended-spectrum beta-lactamase-producing Enterobacterales

This study aimed to analyse the frequency of occurrence of spontaneous decolonization in intensive care unit patients colonized by extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) in order to assess the added value of continuing weekly ESBL-E rectal carriage screening in these patients. In total, 49,468 weekly rectal screening samples taken from 20,846 patients over 12 years were included. Among the 4280 ESBL-E carriers, only 109 patients (2.5%) could be considered decolonized at the end of their hospitalization with at least three consecutive negative samples. Overall, 7957 samples (16.1%) were requested for patients already identified as ESBL-E carriers. Avoiding unnecessary weekly screening following positive ESBL-E colonization results could decrease nursing and laboratory work loads.

Role of surveillance cultures in infection control

Hospital-acquired infections are a known menace to the primary disease, for which a patient is admitted. These infections are twenty times more common in developing countries than in the developed ones. Surveillance for colonised patients can be passive or active process. In many hospitals, active surveillance culture for certain sentinel organisms followed by contact precautions for the same is an important part of infection control policy. Specific measures can be taken on early detection of multidrug-resistant organism, allowing prevention of widespread transmission in hospitals. Cultures are the most conventional and economical microbiological method of detection. The cost of active surveillance is a major challenge, especially for developing nations. These nations lack basic infrastructure and have logistic issues. The guidelines regarding this are not very clearly delineated for developing countries. Each hospital has its own challenges and the process is to be tailor-made accordingly. The following review delineates the various aspects of active surveillance for the colonisation of various organisms and the advantages and disadvantages of the same.

Semi-quantitative cultures of throat and rectal swabs are efficient tests to predict ESBL-Enterobacterales ventilator-associated pneumonia in mechanically ventilated ESBL carriers

PURPOSE

In ICU patients with carriage of extended spectrum beta-lactamase producing Enterobacterales (ESBL-E) and suspected Gram-negative bacilli ventilator-associated pneumonia (GNB-VAP), the quantification of the rectal and throat ESBL-E carriage might predict the ESBL-E involvement in GNB-VAP. Our aim was to evaluate whether a semi-quantitative assessment of rectal/throat ESBL-E carriage can predict ESBL-E-associated VAP in medical ICU patients.

METHODS

From May 2014 to May 2017, all ESBL-E carriers had a semi-quantitative assessment of ESBL-E density in swabs cultures. For those who developed GNB-VAP (diagnosed using bronchoalveolar lavage or plugged telescopic catheter with significant quantitative culture), the last positive swab collected at least 48 h before GNB-VAP onset was selected. Clinical data were extracted from a prospectively collected database.

RESULTS

Among 365 ESBL-E carriers, 82 developed 107 episodes of GNB-VAP (ESBL-E VAP, n = 50; and non-ESBL-E GNB-VAP, n = 57) after 13 days of mechanical ventilation in median. Antimicrobials use before VAP onset was similar between groups. The last swabs were collected 5 days in median before VAP onset. ESBL-E. coli carriers developed ESBL-E VAP less frequently (n = 13, 34%) than others (n = 32, 67.3%, p < .01). Throat swab positivity (39 (78%) vs. 12 (23%), p < .01) was more frequent for ESBL-E VAP. ESBL-E VAP was associated with significantly higher ESBL-E density in rectal swabs. In multivariate models, non-E. coli ESBL-E carriage and rectal ESBL-E carriage density, or throat carriage, remained associated with ESBL-E VAP.

CONCLUSION

In carriers of ESBL-E other than E. coli, ESBL-E throat carriage or a high-density ESBL-E rectal carriage are risk factors of ESBL-E VAP in case of GNB-VAP.

Optimal and responsible use of antibiotics

PURPOSE OF REVIEW

In this review, we focus on the dual face of antibiotic therapy in the critically ill that must harmonize the need for early, appropriate and adequate antibiotic therapy in the individual-infected patient with the obligation to limit antibiotic selection pressure as much as possible to preserve its future potential.

RECENT FINDINGS

Recent articles have highlighted and detailed the various aspects, which determine antibiotic efficacy, and have identified adjunctive treatments, such as source control, which impact outcome. In addition, settings and indications where antibiotics do not improve outcome and may cause harm have been identified.

SUMMARY

Reconciling antibiotic efficacy with the limitations of their use is feasible but requires a dedicated and sustained effort throughout the whole process of clinical decision-making, from initial suspicion of sepsis to its definitive treatment.

Multidrug-resistant bacteria in ICU: fact or myth

PURPOSE OF REVIEW

Antimicrobial resistance (AMR) is increasing in ICUs around the world, but the prevalence is variable. We will review recent literature and try to answer the question whether this is a myth or a new reality, as well as discuss challenges and potential solutions.

RECENT FINDINGS

AMR is diverse, and currently Gram-negative multidrug-resistant organisms (MDROs) are the main challenge in ICUs worldwide. Geographical variation in prevalence of MDROs is substantial, and local epidemiology should be considered to assess the current threat of AMR. ICU patients are at a high risk of infection with MDRO because often multiple risk factors are present. Solutions should focus on reducing the risk of cross-transmission in the ICU through strict infection prevention and control practices and reducing exposure to antimicrobials as the major contributor to the development of AMR.

SUMMARY

AMR is a reality in most ICUs around the world, but the extent of the problem is clearly highly variable. Infection prevention and control as well as appropriate antimicrobial use are the cornerstones to turn the tide.

Impact of colonization pressure on acquisition of extended-spectrum β-lactamase-producing Enterobacterales and meticillin-resistant Staphylococcus aureus in two intensive care units: a 19-year retrospective surveillance

BACKGROUND

Colonization pressure is a risk factor for intensive care unit (ICU)-acquired multi-drug-resistant organisms (MDROs).

AIM

To measure the long-term respective impact of colonization pressure on ICU-acquired extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PE) and meticillin-resistant Staphylococcus aureus (MRSA).

METHODS

All patients admitted to two ICUs (medical and surgical) between January 1997 and December 2015 were included in this retrospective observational study. Rectal and nasal surveillance cultures were obtained at admission and weekly thereafter. Contact precautions were applied for colonized or infected patients. Colonization pressure was defined as the ratio of the number of MDRO-positive patient-days (PDs) of each MDRO to the total number of PDs. Single-level negative binomial regression models were used to evaluate the incidence of weekly MDRO acquisition.

FINDINGS

Among the 23,423 patients included, 2327 (10.0%) and 1422 (6.1%) were colonized with ESBL-PE and MRSA, respectively, including 660 (2.8%) and 351 (1.5%) acquisitions. ESBL-PE acquisition increased from 0.51/1000 patient-exposed days (PEDs) in 1997 to 6.06/1000 PEDs in 2015 (P<0.001). In contrast, MRSA acquisition decreased steadily from 3.75 to 0.08/1000 PEDs (P<0.001). Controlling for period-level covariates, colonization pressure in the previous week was associated with MDRO acquisition for ESBL-PE (P<0.001 and P=0.04 for medical and surgical ICU, respectively), but not for MRSA (P=0.34 and P=0.37 for medical and surgical ICU, respectively). The increase in colonization pressure was significant above 100/1000 PDs for ESBL-PE.

CONCLUSION

Colonization pressure contributed to the increasing incidence of ESBL-PE but not MRSA. This study suggests that preventive control measures should be customized to MDROs.

How Introducing a Registry With Automated Alerts for Carbapenem-resistant Enterobacteriaceae (CRE) May Help Control CRE Spread in a Region

BACKGROUND

Regions are considering the use of electronic registries to track patients who carry antibiotic-resistant bacteria, including carbapenem-resistant Enterobacteriaceae (CRE). Implementing such a registry can be challenging and requires time, effort, and resources; therefore, there is a need to better understand the potential impact.

METHODS

We developed an agent-based model of all inpatient healthcare facilities (90 acute care hospitals, 9 long-term acute care hospitals, 351 skilled nursing facilities, and 12 ventilator-capable skilled nursing facilities) in the Chicago metropolitan area, surrounding communities, and patient flow using our Regional Healthcare Ecosystem Analyst software platform. Scenarios explored the impact of a registry that tracked patients carrying CRE to help guide infection prevention and control.

RESULTS

When all Illinois facilities participated (n = 402), the registry reduced the number of new carriers by 11.7% and CRE prevalence by 7.6% over a 3-year period. When 75% of the largest Illinois facilities participated (n = 304), registry use resulted in a 11.6% relative reduction in new carriers (16.9% and 1.2% in participating and nonparticipating facilities, respectively) and 5.0% relative reduction in prevalence. When 50% participated (n = 201), there were 10.7% and 5.6% relative reductions in incident carriers and prevalence, respectively. When 25% participated (n = 101), there was a 9.1% relative reduction in incident carriers (20.4% and 1.6% in participating and nonparticipating facilities, respectively) and 2.8% relative reduction in prevalence.

CONCLUSIONS

Implementing an extensively drug-resistant organism registry reduced CRE spread, even when only 25% of the largest Illinois facilities participated due to patient sharing. Nonparticipating facilities garnered benefits, with reductions in new carriers.

Individualized antibiotic therapy in the treatment of severe infections

Introduction: Sepsis is a frequent and life-threatening clinical entity and antibiotic treatment is one of the most important interventions, together with source control and hemodynamic resuscitation. Guidelines have highlighted the importance of an early (i.e. within 1-3 h from recognition) and appropriate (i.e. the pathogen is sensitive in vitro to the administered drug) antimicrobial therapy in this setting.Areas covered: Antibiotic therapy should be individualized according to several issues, including early pathogen identification, optimal drug regimens based on pharmacokinetic/pharmacodynamics (PK/PD) and adequate duration using both clinical and biological biomarkers. This narrative review has considered the most relevant studies evaluating these issues.Expert opinion: Rapid identification pathogen resistance profile (i.e. the minimal inhibitory concentration for the available antimicrobials), real-time measurement of drug concentrations with regimen adjustment on MIC and daily measurement of procalcitonin to guide duration of therapy are the main issues to individualize the antibiotic management in critically ill patients.

Prevalence and Risk Factors for Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae Colonization in Intensive Care Units

Active surveillance culture (ASC) can help detect hidden reservoirs, but the routine use of ASC for extended spectrum β-lactamase-producing Enterobacteriaceae is controversial in an endemic situation. We aimed to determine the prevalence and risk factors of extended spectrum β-lactamase-producing Klebsiella pneumoniae (EBSL-Kpn) colonization among intensive care unit (ICU)-admitted patients. Prospective screening of ESBL-Kpn colonization was performed for ICU-admitted patients within 48 hours for two months. A perirectal swab sample was inoculated on MacConkey agar supplemented with 2 µg/mL ceftazidime. ESBL genotype was determined by PCR-sequencing, and clonal relatedness was evaluated by pulsed-field gel electrophoresis (PFGE). The risk factors of ESBL-Kpn colonization were evaluated. The ESBL-Kpn colonization rate among the 281 patients at ICU admission was 6.4% (18/281), and bla_CTX-M-15 was detected in all isolates. ESBL producers also showed resistance to fluoroquinolone (38.9%, 7/18). All isolates had the same ESBL genotype (bla_CTX-M-15) and a highly clustered PFGE pattern, suggesting cross-transmission without a documented outbreak. In univariate analysis, the risk factor for ESBL-Kpn colonization over the control was the length of hospital stay (odds ratio=1.062; P=0.019). Routine use of ASC could help control endemic ESBL–Kpn for ICU patients.

Risk factors for acquisition of carbapenem-resistance during treatment with carbapenem in the intensive care unit: a prospective study

The emergence of carbapenemases in gram-negative aerobes is worrying. The aim of this prospective study was to estimate the incidence of acquisition of carbapenem-resistance during treatment in ICU and to identify the risk factors. This was a prospective, observational, cohort study. This study was conducted at intensive care unit, academic medical center, Toulouse Rangueil University Hospital. Patients were included if they received antibiotic treatment with carbapenem for more than 48 h. Biological samples were taken in accordance with current practice in the unit. The main endpoint was the occurrence of bacterial resistance to carbapenems occurring between the onset of treatment and the patient’s exit from the ICU. Uni- and multi-variate analyses were carried out. Of the 364 patients admitted to the unit between May and November 2014, 78 were included in our study and 16 (20.51%) developed resistance. The two main risk factors were a length of stay in ICU of more than 29 days (HR = 3.61, p = 0.01) and the presence of Pseudomonas aeruginosa in the samples taken before the start of treatment (HR = 5.31, p = 0.002). No resistance due to carbapenemase production was observed in this study. The prescription of carbapenems in the ICU setting must adhere to the expert guidelines. In light of our results, special attention must be paid to patients whose stay in intensive care is prolonged, and those in whom Pseudomonas aeruginosa is isolated from bacteriological samples taken before the beginning of antibiotic therapy.

Active surveillance culture program in asymptomatic patients as a strategy to control multidrug-resistant gram-negative organisms: What should be considered?

The increasing burden of multidrug-resistant gram-negative bacilli (MDR-GNB) infection has highlighted the urgent requirement for efficient prevention and control strategies. A routine active surveillance culture (ASC) program of asymptomatic carriers as part of an infection prevention strategy for MDR-GNB still has some controversy. An ASC program for colonized patients may be beneficial depending on the targeted population, level of endemicity, the species of pathogen, and the combination of multifaceted strategies. Multimodal infection control and prevention strategies are crucial for implementation in resources-limited settings. After discovering the culprit, it is a challenge to control MDR-GNB by containment or eradication and prevent cross-transmission. An ASC program should consider both the local epidemiology and cost-effectiveness based on the available resources in endemic MDR-GNB areas in the Asia-Pacific region.

Strategies for the eradication of extended-spectrum beta-lactamase or carbapenemase-producing Enterobacteriaceae intestinal carriage

Introduction: Among the multidrug resistant pathogens, extended-spectrum beta-lactamase (ESBL-E) or carbapenemase-producing Enterobacteriaceae (CPE) are currently considered the main threat due to the scarcity of therapeutic options and their rapid spread around the globe. In addition to developing new antibiotics and stopping transmission, recent research has focused on 'decolonization' strategies to eradicate the carriage of ESBL-E/CPE before infection occurs. Areas covered: In this narrative review, we aim to describe the current evidence of decolonization strategies for ESBL-E or CPE intestinal carriage. We first define decolonization and highlight the issues related to the lack of standardized definitions, then we summarize the available data on the natural history of colonization. Finally, we review the strategies assessed over the past 10 years for ESBL and CPE decolonization: oral antibiotics, probiotics and more recently fecal microbiota transplantation. We conclude by presenting the risks and uncertainties associated with these strategies. Expert opinion: The evidence available today is too low to recommend decolonization strategies for ESBL-E or CPE in routine clinical practice. The potential increase of resistance and the impact of microbiome manipulation should not be underestimated. Some of these decolonization strategies may nevertheless be effective, at least in temporarily suppressing colonization, which could be useful for specific populations such as high-risk patients. Effectiveness and long-term effects must be properly assessed through well-designed randomized controlled trials.

Rationalizing antimicrobial therapy in the ICU: a narrative review

The massive consumption of antibiotics in the ICU is responsible for substantial ecological side effects that promote the dissemination of multidrug-resistant bacteria (MDRB) in this environment. Strikingly, up to half of ICU patients receiving empirical antibiotic therapy have no definitively confirmed infection, while de-escalation and shortened treatment duration are insufficiently considered in those with documented sepsis, highlighting the potential benefit of implementing antibiotic stewardship programs (ASP) and other quality improvement initiatives. The objective of this narrative review is to summarize the available evidence, emerging options, and unsolved controversies for the optimization of antibiotic therapy in the ICU. Published data notably support the need for better identification of patients at risk of MDRB infection, more accurate diagnostic tools enabling a rule-in/rule-out approach for bacterial sepsis, an individualized reasoning for the selection of single-drug or combination empirical regimen, the use of adequate dosing and administration schemes to ensure the attainment of pharmacokinetics/pharmacodynamics targets, concomitant source control when appropriate, and a systematic reappraisal of initial therapy in an attempt to minimize collateral damage on commensal ecosystems through de-escalation and treatment-shortening whenever conceivable. This narrative review also aims at compiling arguments for the elaboration of actionable ASP in the ICU, including improved patient outcomes and a reduction in antibiotic-related selection pressure that may help to control the dissemination of MDRB in this healthcare setting.