Risk factors for colonization with extended-spectrum beta-lactamase-producing bacteria and intensive care unit admission

Predictive Model for Extended-Spectrum β-Lactamase-Producing Bacterial Infections Using Natural Language Processing Technique and Open Data in Intensive Care Unit Environment: Retrospective Observational Study

BACKGROUND

Machine learning has advanced medical event prediction, mostly using private data. The public MIMIC-3 (Medical Information Mart for Intensive Care III) data set, which contains detailed data on over 40,000 intensive care unit patients, stands out as it can help develop better models including structured and textual data.

OBJECTIVE

This study aimed to build and test a machine learning model using the MIMIC-3 data set to determine the effectiveness of information extracted from electronic medical record text using a named entity recognition, specifically QuickUMLS, for predicting important medical events. Using the prediction of extended-spectrum β-lactamase (ESBL)-producing bacterial infections as an example, this study shows how open data sources and simple technology can be useful for making clinically meaningful predictions.

METHODS

The MIMIC-3 data set, including demographics, vital signs, laboratory results, and textual data, such as discharge summaries, was used. This study specifically targeted patients diagnosed with Klebsiella pneumoniae or Escherichia coli infection. Predictions were based on ESBL-producing bacterial standards and the minimum inhibitory concentration criteria. Both the structured data and extracted patient histories were used as predictors. In total, 2 models, an L1-regularized logistic regression model and a LightGBM model, were evaluated using the receiver operating characteristic area under the curve (ROC-AUC) and the precision-recall curve area under the curve (PR-AUC).

RESULTS

Of 46,520 MIMIC-3 patients, 4046 were identified with bacterial cultures, indicating the presence of K pneumoniae or E coli. After excluding patients who lacked discharge summary text, 3614 patients remained. The L1-penalized model, with variables from only the structured data, displayed a ROC-AUC of 0.646 and a PR-AUC of 0.307. The LightGBM model, combining structured and textual data, achieved a ROC-AUC of 0.707 and a PR-AUC of 0.369. Key contributors to the LightGBM model included patient age, duration since hospital admission, and specific medical history such as diabetes. The structured data-based model showed improved performance compared to the reference models. Performance was further improved when textual medical history was included. Compared to other models predicting drug-resistant bacteria, the results of this study ranked in the middle. Some misidentifications, potentially due to the limitations of QuickUMLS, may have affected the accuracy of the model.

CONCLUSIONS

This study successfully developed a predictive model for ESBL-producing bacterial infections using the MIMIC-3 data set, yielding results consistent with existing literature. This model stands out for its transparency and reliance on open data and open-named entity recognition technology. The performance of the model was enhanced using textual information. With advancements in natural language processing tools such as BERT and GPT, the extraction of medical data from text holds substantial potential for future model optimization.

Identifying the Optimal Look-back Period for Prior Antimicrobial Resistance Clinical Decision Support

BACKGROUND

Lack of consensus on the appropriate look-back period for multi-drug resistance (MDR) complicates antimicrobial clinical decision support. We compared the predictive performance of different MDR look-back periods for five common MDR mechanisms (MRSA, VRE, ESBL, AmpC, CRE).

METHODS

We mapped microbiological cultures to MDR mechanisms and labeled them at different look-back periods. We compared predictive performance for each look-back period-MDR combination using precision, recall, F1 scores, and odds ratios.

RESULTS

Longer look-back periods resulted in lower odds ratios, lower precisions, higher recalls, and lower delta changes in precision and recall compared to shorter periods. We observed higher precision with more information available to clinicians.

CONCLUSION

A previously positive MDR culture may have significant enough precision depending on the mechanism of resistance and varying information available. One year is a clinically relevant and statistically sound look-back period for empiric antimicrobial decision-making at varying points of care for the studied population.

Effects of antimicrobial therapy duration and class on risk of antimicrobial-resistant Gram-negative bacillus bloodstream infection in patients with AML

BACKGROUND

Antimicrobial-resistant Gram-negative bacilli (ARGNB) bloodstream infection (BSI) has been associated with prior antibiotic exposure among hematologic malignancy patients. The relationships between days of therapy (DOT), antimicrobial class, and ARGNB BSI risk are poorly understood.

METHODS

This is a single-center, case-control study of acute myeloid leukemia (AML) patients including 115 cases with ARGNB BSI and 230 matched controls with non-ARGNB BSI between January 1, 2007 and December 31, 2018. Fixed- and mixed-effects logistic regression was used to examine relationships between antibiotic DOT and risk of ARGNB BSI. Admission to an intensive care unit (ICU) within 7 days, 30-day mortality, and Pitt Bacteremia Score (PBS) were secondary outcomes.

RESULTS

Prior isolation of a antimicrobial-resistant organism (ARO) (OR 4.45 95% CI 1.46, 13.54), surgery within 90 days (OR 3.71, 95% CI 1.57, 8.73), aminoglycoside DOT (OR 1.14, 95% CI 1.05, 1.23), cefepime DOT (OR 1.09, 95% CI 1.05, 1.13), and carbapenem DOT (OR 1.10, 95% CI 1.05, 1.16) were associated with increased odds of ARGNB BSI. Days since last antibiotic administration (OR 0.98, 95% CI 0.97, 0.99) and inpatient days within 90 days (OR 0.95, 95% CI 0.93, 0.98) showed reduced odds of ARGNB BSI. Total antimicrobial DOT regardless of class was not associated with ARGNB BSI. ARGNB BSI was associated with increased 30-day mortality (OR 2.86, 95% CI 1.57, 5.22) CONCLUSIONS: Among AML patients with GNB BSI, greater DOT of aminoglycosides, cefepime, and carbapenems in the 90 days prior to BSI were associated with increased odds of ARGNB BSI.

Colonization of multidrug-resistant Gram-negative bacteria increases risk of surgical site infection after hemorrhoidectomy: a cross-sectional study of two centers in southern China

PURPOSE

The present study aims to determine the rectoanal colonization rate and risk factors for the colonization of present multidrug-resistant bacteria (MDRBs). In addition, the relationship between MDRB colonization and surgical site infection (SSI) following hemorrhoidectomy was explored.

METHODS

A cross-sectional study was conducted in the Department of Colorectal Surgery of two hospitals. Patients with hemorrhoid disease, who underwent hemorrhoidectomy, were included. The pre-surgical screening of multidrug-resistant Gram-negative bacteria (MDR-GNB) colonization was performed using rectal swabs on the day of admission. Then, the MDRB colonization rate was determined through the rectal swab. Logistic regression models were established to determine the risk factors for MDRB colonization and SSI after hemorrhoidectomy. A p-value of < 0.05 was considered statistically significant.

RESULTS

A total of 432 patients met the inclusion criteria, and the MDRB colonization prevalence was 21.06% (91/432). The independent risk factors for MDRB colonization were as follows: patients who received ≥ 2 categories of antibiotic treatment within 3 months (odds ratio (OR): 3.714, 95% confidence interval (CI): 1.436-9.605, p = 0.007), patients with inflammatory bowel disease (IBD; OR: 6.746, 95% CI: 2.361-19.608, p < 0.001), and patients with high serum uric acid (OR: 1.006, 95% CI: 1.001-1.010, p = 0.017). Furthermore, 41.57% (37/89) of MDRB carriers and 1.81% (6/332) of non-carriers developed SSIs, with a total incidence of 10.21% (43/421). Based on the multivariable model, the rectoanal colonization of MDRBs (OR: 32.087, 95% CI: 12.052-85.424, p < 0.001) and hemoglobin < 100 g/L (OR: 4.130, 95% CI: 1.556-10.960, p = 0.004) were independently associated with SSI after hemorrhoidectomy.

CONCLUSION

The rectoanal colonization rate of MDRBs in hemorrhoid patients is high, and this was identified as an independent risk factor for SSI after hemorrhoidectomy.

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.

Know your Microbe Foes: The Role of Surveillance in Combatting Antimicrobial Resistance

Antibiotic-resistant organisms (AROs) are difficult and costly to treat, associated with high mortality rates, and are on the rise. In the United States, there is limited tracking of AROs, which can contribute to transmission and inhibit infection prevention interventions. Surveillance is limited by a lack of standardized methods for colonization screening and limited communication regarding patient ARO-status between healthcare settings. Some regional surveillance and reporting efforts are in place for extensively-resistant AROs such as carbapenem-resistant Enterobacterales (CRE), but need to be further expanded nationwide and to include other AROs such as extended-spectrum β-lactamase (ESBL) producing organisms. Increased surveillance of ARO infections and colonization will inform future targeted intervention and infection prevention strategies.

Acquisition of extended-spectrum cephalosporin-resistant Gram-negative bacteria: epidemiology and risk factors in a 6-year cohort of 507 severe trauma patients

OBJECTIVES

Severe trauma patients are at higher risk of infection and often exposed to antibiotics, which could favor acquisition of antimicrobial resistance. In this study, we aimed to assess prevalence, acquisition, and factors associated with acquisition of extended-spectrum cephalosporin-resistant Gram-negative bacteria (ESCR-GNB) in severe trauma patients.

METHODS

We conducted a retrospective monocentric cohort study in a French level one Regional Trauma Centre between 01 January 2010and 31 December 2015. Patients admitted for ≥ 7 days, with an Injury Severity Score ≥ 15, and ≥ 1 microbiological sample were included in the analysis. Prevalence and acquisition rate of ESCR-GNB were determined then, factors associated with ESCR-GNB acquisition were assessed using a Cox model.

RESULTS

Of 1873 patients admitted during the study period, 507 were included (median Injury Severity Score = 29 [22-34] and median intensive care unit length of stay = 16 days [10-28]). Most of them (450; 89%) had an antimicrobial therapy. Prevalence of ESCR-GNB increased from 13% to 33% during intensive care unit stay, bringing the ESCR-GNB acquisition rate to 29%. Acquisition of ESCR-GNB was mainly related to AmpC beta-lactamase Enterobacterales and was independently associated with mechanical ventilation needs (hazard ratio [HR] = 6.39; 95% confidence interval [CI] [1.51-27.17]; P = 0.01), renal replacement therapy needs (HR = 2.44; 95% CI [1.24-4.79]; P = 0.01), exposure to cephalosporins (HR = 1.06; 95% CI [1.01-1.12]; P = 0.02), and/or combination therapy with non-beta-lactam antibiotics such as vancomycin, linezolid, clindamycin, or metronidazole (HR = 1.03; 95% CI [1.01-1.06]; P = 0.02).

CONCLUSIONS

Acquisition of ESCR-GNB was prevalent in severe trauma patients. Our results suggest selecting antibiotics with caution, particularly in the most severely ill.

Creation and Internal Validation of a Clinical Predictive Model for Fluconazole Resistance in Patients With Candida Bloodstream Infection

Background

Fluconazole is recommended as first-line therapy for candidemia when risk of fluconazole resistance (fluc-R) is low. Lack of methods to estimate resistance risk results in extended use of echinocandins and prolonged hospitalization. This study aimed to develop a clinical predictive model to identify patients at low risk for fluc-R where initial or early step-down fluconazole would be appropriate.

Methods

Retrospective analysis of hospitalized adult patients with positive blood culture for Candida spp from 2013 to 2019. Multivariable logistic regression model was performed to identify factors associated with fluc-R. Stepwise regression was performed on bootstrapped samples to test individual variable stability and estimate confidence intervals (CIs). We used receiver operating characteristic curves to assess performance across the probability spectrum.

Results

We identified 539 adults with candidemia and 72 Candida isolates (13.4%) were fluc-R. Increased risk of fluc-R was associated with older age, prior bacterial bloodstream infection (odds ratio [OR], 2.02 [95% CI, 1.13-3.63]), myelodysplastic syndrome (OR, 3.09 [95% CI, 1.13-8.44]), receipt of azole therapy (OR, 5.42 [95% CI, 2.90-10.1]) within 1 year of index blood culture, and history of bone marrow or stem cell transplant (OR, 2.81 [95% CI, 1.41-5.63]). The model had good discrimination (optimism-corrected c-statistic 0.771), and all of the selected variables were stable. The prediction model had a negative predictive value of 95.7% for the selected sensitivity cutoff of 90.3%.

Conclusions

This model is a potential tool for identifying patients at low risk for fluc-R candidemia to receive first-line or early step-down fluconazole.

Extended Spectrum β-Lactamase Producing Lactose Fermenting Bacteria Colonizing Children with Human Immunodeficiency Virus, Sickle Cell Disease and Diabetes Mellitus in Mwanza City, Tanzania: A Cross-Sectional Study

Rectal carriage of extended spectrum β-lactamase-lactose fermenters (ESBL-LF) is the major risk factor for the development of subsequent endogenous infections. This study determined the patterns and factors associated with the rectal carriage of ESBL-LF among children with Human Immunodeficiency Virus (HIV), Diabetes Mellitus (DM), and Sickle Cell Disease (SCD) attending clinics at different health care facilities in the city of Mwanza, Tanzania. A cross-sectional study was conducted among children living with HIV (n = 236), DM (n = 42) and SCD (n = 126) between July and September 2021. Socio-demographic and clinical data were collected using a structured questionnaire. Rectal swabs/stool samples were collected and processed to detect the rectal carriage of ESBL-LF following laboratory standard operating procedures (SOPs). Descriptive statistical analysis was conducted using STATA 13.0. The overall prevalence of ESBL-LF carriage was 94/404 (23.3%). Significantly higher resistance was observed to ampicillin, trimethoprim-sulfamethoxazole, and tetracycline among Enterobacteriaceae isolated from HIV infected children than in non-HIV infected children (p < 0.05). The commonest ESBL allele 45/62 (72.6%) detected was blaCTX-M. Generally, a parent’s low education level was found to be associated with ESBL-LF colonization among children living with HIV; (OR 4.60 [95%CI] [1.04−20], p = 0.044). A higher proportion of ESBL-LF from DM 10/10 (100%) carried ESBL genes than ESBL-LF from HIV 37/56 (66.1%) and SCD 15/28 (53.6%), p = 0.02. There is a need to collect more data regarding trimethoprim-sulfamethoxazole (SXT) prophylaxis and antibiotic resistance to guide the decision of providing SXT prophylaxis in HIV-infected children especially at this time, when testing and treatment is carried out.

Gastrointestinal colonization of Extended-Spectrum Beta lactamase producing bacteria among children below five years of age hospitalized with fever in Dar es Salaam, Tanzania

BACKGROUND

Gastrointestinal colonization of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) is of concern because prior colonization increases risk for subsequent infections. To date, the link between ESBL-PE fecal carriage and the risk of subsequent ESBL-PE infection has not been well established, and information on carriage of such pathogens among children with invasive infections such as blood stream infections (BSI) remains to be explored worldwide.

METHODS

This cross-sectional study was conducted among childrenunder the age of 5 years admitted for febrile illness in Dar es Salaam, Tanzania, between March 2017 and July 2018. We used rectal swabs to screen for ESBL-PE using selective media, ChromID® ESBL. Bacterial isolates were identified by MALDI-TOF.Blood cultures were drawn from all children. Antimicrobial susceptibility testingwas done using disk diffusion method. ESBL alleles were identified by Real-Time PCR and sequencing.

RESULTS

The overall prevalence of ESBL-PE carriage was 56% (112/200) and washighestamong children 4-6 months old (17/21, 81%) (p =0.05). Children with BSI had high ESBL-PE carriage (78.4%) compared to those without BSI (53.1%)(p=0.02; AOR 3.4, 95% CI1.20-9.58).The most common isolate was E.coli (64/112, 45%). Sixteen pairs of ESBL-PEisolates(from the gut and from blood)had similar antimicrobial susceptibility profile. We detectedbla_CTX-M gene in 97% of all phenotypically detected ESBL-PE; among those,bla_CTX-M-15 was dominant (99%).

CONCLUSIONS

We report a high prevalence of ESBL-PEfecal carriage among children with BSI in Tanzania. Colonization of ESBL-PEwasa risk factor for ESBL-BSI.

Impact of the Acceptance of the Recommendations Made by a Meropenem Stewardship Program in a University Hospital: A Pilot Study

Antimicrobial stewardship programs (ASP) promote appropriate antimicrobial use. We present a 4-year retrospective study that evaluated the clinical impact of the acceptance of the recommendations made by a meropenem-focused ASP. A total of 318 meropenem audits were performed. The ASP team (comprising infectious disease physicians, pharmacists and microbiologists) considered meropenem use in 96 audits (30.2%) to be inappropriate. The reasons to consider these uses inappropriate were the possibility of de-escalating to a narrower-spectrum antibiotic, in 66 (68.7%) audits, and unnecessary meropenem use, in 30 (31.3%) audits. The ASP team recommended de-escalation in 66 audits (68.7%) and discontinuation of meropenem in 30 audits (31.3%). ASP interventions were stratified according to whether or not recommendations were followed. The group in which recommendations were accepted and followed (i.e., accepted audit, AA) included 66 audits (68.7%) and the group in which recommendations were not followed (i.e., rejected audit, RA) included 30 (31.3%) audits. The comorbidity of the AA group (Charlson score) was higher than in the RA group (7.0 (5.0–9.0) vs. 6.0 (4.0–7.0), p = 0.02). Discontinuation of meropenem was recommended in 83.3% of audits in the AA group vs. 62.2% in the RA group (OR 3.05 (1.03–8.99), p = 0.04). Ertapenem de-escalation resulted in a 100% greater rate of follow-up compared with the non-carbapenem option (100% vs. 51.9%, OR 1.50 (1.21–1.860), p = 0.001). Significant differences were observed in the AA group when cultures were taken before antibiotic prescription—98.5% vs. 83.3% (p = 0.01, OR 13.0 (1.45–116.86))—or when screening cultures were taken—45.5% vs. 19.2% (p = 0.03, OR 3.5 (1.06–11.52)). There were no differences between the groups in terms of overall mortality and 30-day mortality, length of stay, Clostridiodes difficile infection, 30-day readmission or hospitalization costs. In conclusion, meropenem ASP recommendations contributed to a decrease in meropenem prescription without worsening clinical and economic outcomes.

Association of methicillin resistance with mortality of hospital-acquired Staphylococcus aureus bacteremia

Objective

Methicillin-resistant (MR) Staphylococcus aureus bacteremia (SAB) is associated with higher mortality rates than methicillin-susceptible (MS) SAB. This study assessed potential predictors of mortality and evaluated the association of methicillin resistance with mortality in patients with SAB.

Methods

We conducted a retrospective cohort study in patients with hospital-acquired SAB, from 2009 to 2018. Clinical features of patients with MR-SAB were compared with those of patients with MS-SAB and predictors of 30-day mortality were determined using Cox regression analysis.

Results

Among 162 patients, 56.8% had MR-SAB. Overall 30-day mortality was 19.1%; MR-SAB had higher mortality (25.0%) than MS-SAB (11.4%). Univariate analysis highlighted long-term hospitalization, prior antibiotics use, and delayed initiation of appropriate antibiotics as risk factors. Cox regression analysis showed that respiratory tract source, Pitt bacteremia score, Charlson comorbidity index, and appropriate antibiotic therapy within 24 hours were independently and significantly associated with 30-day mortality outcome.

Conclusions

Methicillin resistance was not an independent risk factor for mortality in patients with SAB. Early, appropriate antibiotic treatment is an important prognostic factor.

Clinical prediction tool for extended-spectrum beta-lactamase-producing enterobacterales as the etiology of a bloodstream infection in solid organ transplant recipients

BACKGROUND

Multidrug-resistant Gram-negative bacterial infections are increasingly common among solid organ transplant (SOT) recipients, leading to challenges in the selection of empiric antimicrobial therapy. We sought to develop a clinical tool to predict which SOT recipients are at high risk for extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (EB) bloodstream infection (BSI).

METHODS

A multicenter case-control study was performed. The source population included SOT recipients with an EB BSI between 2005 and 2018. Cases were those with ESBL-EB BSI; controls were those with non-ESBL EB BSI. The population was subdivided into derivation and validation cohorts based on study site. The predictive tool was developed in the derivation cohort through iterative multivariable logistic regression analyses that maximized the area under the receiver-operating curve (AUC). External validity was assessed using the validation cohort.

RESULTS

A total of 897 SOT recipients with an EB BSI were included, of which 539 were assigned to the derivation cohort (135, 25% ESBL-EB) and 358 to the validation cohort (221, 62% ESBL-EB). Using multivariable analyses, the most parsimonious model that was predictive of ESBL-EB BSI consisted of 10 variables, which fell into four clinical categories: prior colonization or infection with EB organisms, recent antimicrobial exposures, severity of preceding illness, and immunosuppressive regimen. This model achieved an AUC of 0.81 in the derivation cohort and 0.68 in the validation cohort.

CONCLUSIONS

Though further refinements are needed in additional populations, this tool shows promise for guiding empiric therapy for SOT recipients with EB BSI.

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.

Frequency, Local Dynamics, and Genomic Characteristics of ESBL-Producing Escherichia coli Isolated From Specimens of Hospitalized Horses

Previous research identified veterinary clinics as hotspots with respect to accumulation and spread of multidrug resistant extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (EC). Therefore, promoting the prudent use of antibiotics to decrease selective pressure in that particular clinical environment is preferable to enhance biosecurity for animal patients and hospital staff. Accordingly, this study comparatively investigated the impact of two distinct perioperative antibiotic prophylaxis (PAP) regimens (short-term versus prolonged) on ESBL-EC carriage of horses subjected to colic surgery. While all horses received a combination of penicillin/gentamicin (P/G) as PAP, they were assigned to either the “single-shot group” (SSG) or the conventional “5-day group” (5DG). Fecal samples collected on arrival (t₀), on the 3rd (t₁) and on the 10th day after surgery (t₂) were screened for ESBL-EC. All isolates were further investigated using whole genome sequences. In total, 81 of 98 horses met the inclusion criteria for this study. ESBL-EC identified in samples available at t₀, t₁ and t₂ were 4.8% (SSG) and 9.7% (5DG), 37% (SSG) and 47.2% (5DG) as well as 55.6% (SSG) and 56.8% (5DG), respectively. Regardless of the P/G PAP regimen, horses were 9.12 times (95% CI 2.79–29.7) more likely to carry ESBL-EC at t₁ compared to t₀ (p < 0.001) and 15.64 times (95% CI 4.57–53.55) more likely to carry ESBL-EC at t₂ compared to t₀ (p < 0.001). ESBL-EC belonging to sequence type (ST) 10, ST86, ST641, and ST410 were the most prevalent lineages, with bla_CTX–M–1 (60%) being the dominant ESBL gene. A close spatio-temporal relationship between isolates sharing a particular ST was revealed by genome analysis, strongly indicating local spread. Consequently, hospitalization itself has a strong impact on ESBL-EC isolation rates in horses, possibly masking differences between distinct PAP regimens. The results of this study reveal accumulation and spread of multi-drug resistant ESBL-EC among horses subjected to colic surgery with different P/G PAP regimens, challenging the local hygiene management system and work-place safety of veterinary staff. Moreover, the predominance of particular ESBL-EC lineages in clinics providing health care for horses needs further investigation.

Relevance of intra-hospital patient movements for the spread of healthcare-associated infections within hospitals - a mathematical modeling study

The aim of this study is to analyze patient movement patterns between hospital departments to derive the underlying intra-hospital movement network, and to assess if movement patterns differ between patients at high or low risk of colonization. For that purpose, we analyzed patient electronic medical record data from five hospitals to extract information on risk stratification and patient intra-hospital movements. Movement patterns were visualized as networks, and network centrality measures were calculated. Next, using an agent-based model where agents represent patients and intra-hospital patient movements were explicitly modeled, we simulated the spread of multidrug resistant enterobacteriacae (MDR-E) inside a hospital. Risk stratification of patients according to certain ICD-10 codes revealed that length of stay, patient age, and mean number of movements per admission were higher in the high-risk groups. Movement networks in all hospitals displayed a high variability among departments concerning their network centrality and connectedness with a few highly connected departments and many weakly connected peripheral departments. Simulating the spread of a pathogen in one hospital network showed positive correlation between department prevalence and network centrality measures. This study highlights the importance of intra-hospital patient movements and their possible impact on pathogen spread. Targeting interventions to departments of higher (weighted) degree may help to control the spread of MDR-E. Moreover, when the colonization status of patients coming from different departments is unknown, a ranking system based on department centralities may be used to design more effective interventions that mitigate pathogen spread.

Pathogens including multidrug resistant enterobacteriacae (MDR-E) inside hospital settings are associated with higher morbidity, mortality, and healthcare costs. Better understanding of the transmission routes of these pathogens is required to develop targeted and efficient measures to contain the spread of MDR-E in a hospital. We analyzed datasets from five hospitals in different countries to explore patient movement patterns between departments of these hospitals (intra-hospital movements). We assessed whether movement patterns differ between patients at high or low risk of colonization. Our results show that in every intra-hospital network, there exist a few departments which are strongly connected and many peripheral departments which are loosely connected. High-risk patients stay on average longer in the hospital, and move more frequently between departments than low-risk patients. Targeting interventions to strongly connected departments may help to reduce pathogen spread inside the hospital. To explore this, we simulated the spread of MDR-E inside one hospital using an agent-based model that includes patient movements. In the simulations, we found positive correlations between departments’ prevalence and network characteristics such as degree and weighted degree, thus highlighting the importance of targeting interventions to departments of higher (weighted) degree to control the spread of MDR-E.

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.

Gastrointestinal Tract Colonization Rate of Extended-Spectrum Beta-Lactamase- and Carbapenemase-Producing Enterobacteriaceae and Associated Factors Among Hospitalized Patients in Arba Minch General Hospital, Arba Minch, Ethiopia

Background

The incidence of hospital-acquired enterobacteria that produce extended-spectrum beta-lactamases (ESBLs) is on the rise worldwide. Colonization of gastrointestinal tract by extended-spectrum beta-lactamase Enterobacteriaceae, a prominent causative agent, results in life-threatening infections.

Objective

To determine the rate of gastrointestinal colonization by extended-spectrum beta-lactamase- and carbapenemase-producing Enterobacteriaceae and also to elucidate the antibiotic susceptibility profile and associated risk factors among hospitalized patients in Arba Minch General Hospital, Ethiopia.

Methodology

A facility-based cross-sectional study was conducted in Arba Minch General Hospital from May 2018 to July 2019. Sociodemographic data and associated factors were collected using a pre-tested-structured questionnaire. Stool specimens were collected using sterile stool cups. Each sample was then inoculated onto MacConkey agar. Bacterial isolates were identified using various biochemical tests. Screening and confirmatory tests for extended-spectrum beta-lactamase- and carbapenemase-producing Enterobacteriaceae were performed using the modified Kirby–Bauer disc diffusion technique. Statistical package for Social Science was used to analyze the data. The P-value ≤0.05 was considered as statistically significant.

Results

A total of 421 hospitalized patients were enrolled in this study of which there were 240 (57%) females. The mean age of the study participants was 28.8 with SD of 15.7. Majority of participants were in the age range of 25–40 years 179 (42.5%). About 146 (34.7%) participants were found to be colonized by extended-spectrum beta-lactamase-producing Enterobacteriaceae. The predominant ESBL-producing isolates were Escherichia coli 62 (42.46%) followed by Klebsiella pneumoniae 60 (41.09%). Six (1.43%) carbapenemase-producing K. pneumoniae were isolated. ESBL-producing Enterobacteriaceae showed higher resistance against tetracycline (91.1%) and cotrimoxazole (93.84%). Colonization of the gastrointestinal tract by ESBL showed statistically significant association with regard to chronic diseases (p<0.001) and the administration of oral antibiotics after admission (p=0.020).

Conclusion

The overall colonization rate of the gastrointestinal tract by extended-spectrum beta-lactamase-producing Enterobacteriaceae was prominent. The extended-spectrum beta-lactamase-producing isolates exhibited a higher level of resistance against the commonly used antibiotics which further needs greater attention.

Quantifying risk of disease due to extended-spectrum β-lactamase producing Enterobacteriaceae in patients who are colonized at ICU admission

BACKGROUND

The prevalence of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) has globally increased and spread to the community. No clinical score is available to select carriers in whom these organisms can be empirically targeted at ICU admission.

METHODS

We prospectively assessed between 2009 and 2017 the prevalence of ESBL-PE infection in carriers at ICU admission. A logistic regression was used to determine independent risk factors associated with ESBL-PE infection, and to build a clinical risk score.

RESULTS

Of the 8,061 admissions over the study 7-year period, 745 (9%) patients were ESBL-PE carriers at admission, of whom 395 had infections at ICU admission including 59 (15%) who had culture-proven ESBL-PE related infection. By multivariable analysis, age >60 years, cirrhosis, being on broad-spectrum antibiotics within the past three months, urinary or intra-abdominal source of infection, and the absence of chronic pulmonary disease, were the five independent factors associated with ESBL-PE infection in carriers. A clinical risk score ranging from 0 to 7 was built based on these variables, with an area under the receiver operating characteristic curve (ROC) of 0.82 (95% CI 0.78-0.86); p <0.001. The prevalence of ESBL-PE infection for clinical risk scores of 0-1, 2-3, 4-5, or 6-7 was 0%, 4%, 26%, and 49%, respectively. The negative predictive value when Mondor ESBL risk score is <4 was 97%.

CONCLUSION

ESBL-PE related infection was not common in carriers at ICU admission. A clinical risk score may spare ESBL-PE carriers with lower risk of ESBL-PE infection at ICU admission unnecessary empiric carbapenem therapy.

Predicting Carbapenem-Resistant Enterobacteriaceae Carriage at the Time of Admission Using a Statewide Hospital Discharge Database

BACKGROUND

Timely identification of patients likely to harbor carbapenem-resistant Enterobacteriaceae (CRE) can help health care facilities provide effective infection control and treatment. We evaluated whether a model utilizing prior health care information from a state hospital discharge database could predict a patient's probability of CRE colonization at the time of hospital admission.

METHODS

We performed a case-control study using the Illinois hospital discharge database. From a 2014-2015 patient cohort, we defined cases as index adult patient hospital encounters with a positive CRE culture collected within the first 3 days of hospitalization, as reported to the Illinois XDRO registry; controls were all patient admissions from the same hospital and month. We split the data into training (~60%) and validation (~40%) sets and developed a logistic regression model to estimate coefficients for predictors of interest.

RESULTS

We identified 486 index cases and 340 005 controls. Independent risk factors for CRE at the time of admission were age, number of short-term acute care hospital (STACH) hospitalizations in the prior 365 days, mean STACH length of stay, number of long-term acute care hospital (LTACH) hospitalizations in the prior 365 days, mean LTACH length of stay, current admission to LTACH, and prior hospital admission with an infection diagnosis code. When applying the model to the validation data set, the area under the receiver operating characteristic curve was 0.84.

CONCLUSIONS

A prediction model utilizing prior health care exposure information could discriminate patients who were likely to harbor CRE at the time of hospital admission.

Tractable targets for meropenem-sparing antimicrobial stewardship interventions

Background

As meropenem is a restricted antimicrobial, lessons learned from its real-life usage will be applicable to antimicrobial stewardship (AMS) more generally.

Objectives

To retrospectively evaluate meropenem usage at our institution to identify targets for AMS interventions.

Methods

Patients receiving meropenem documented with an ‘alert antimicrobial’ form at two tertiary care UK hospitals were identified retrospectively. Clinical records and microbiology results were reviewed.

Results

A total of 107 adult inpatients receiving meropenem were identified. This was first-line in 47% and escalation therapy in 53%. Source control was required in 28% of cases after escalation, for predictable reasons. Those ultimately requiring source control had received more prior antimicrobial agents than those who did not (P = 0.03). Meropenem was rationalized in 24% of cases (after median 4 days). Positive microbiology enabled rationalization (OR 12.3, 95% CI 2.7–55.5, P = 0.001) but rates of appropriate sampling varied. In cases with positive microbiology where meropenem was not rationalized, continuation was retrospectively considered clinically and microbiologically necessary in 8/40 cases (0/17 empirical first-line usage). Rationalization was more likely when meropenem susceptibility was not released on the microbiology report (OR 5.2, 95% CI 1.3–20.2, P = 0.02). Input from an infection specialist was associated with a reduced duration of meropenem therapy (P < 0.0001). Early review by an infection specialist has the potential to further facilitate rationalization.

Conclusions

In real-life clinical practice, core aspects of infection management remain tractable targets for AMS interventions: microbiological sampling, source control and infection specialist input. Further targets include supporting rationalization to less familiar carbapenem-sparing antimicrobials, restricting first-line meropenem usage and selectively reporting meropenem susceptibility.

Development of a bedside tool to predict the probability of drug-resistant pathogens among hospitalized adult patients with gram-negative infections

Background

We developed a clinical bedside tool to simultaneously estimate the probabilities of third-generation cephalosporin-resistant Enterobacteriaceae (3GC-R), carbapenem-resistant Enterobacteriaceae (CRE), and multidrug-resistant Pseudomonas aeruginosa (MDRP) among hospitalized adult patients with Gram-negative infections.

Methods

Data were obtained from a retrospective observational study of the Premier Hospital that included hospitalized adult patients with a complicated urinary tract infection (cUTI), complicated intra-abdominal infection (cIAI), hospital-acquired/ventilator-associated pneumonia (HAP/VAP), or bloodstream infection (BSI) due to Gram-negative bacteria between 2011 and 2015. Risk factors for 3GC-R, CRE, and MDRP were ascertained by multivariate logistic regression, and separate models were developed for patients with community-acquired versus hospital-acquired infections for each resistance phenotype (N = 6). Models were converted to a singular user-friendly interface to estimate the probabilities of a patient having an infection due to 3GC-R, CRE, or MDRP when ≥ 1 risk factor was present.

Results

Overall, 124,068 patients contributed to the dataset. Percentages of patients admitted for cUTI, cIAI, HAP/VAP, and BSI were 61.6, 4.6, 16.5, and 26.4%, respectively (some patients contributed > 1 infection type). Resistant infection rates were 1.90% for CRE, 12.09% for 3GC-R, and 3.91% for MDRP. A greater percentage of the resistant infections were community-acquired relative to hospital-acquired (CRE, 1.30% vs 0.62% of 1.90%; 3GC-R, 9.27% vs 3.42% of 12.09%; MDRP, 2.39% vs 1.59% of 3.91%). The most important predictors of having an 3GC-R, CRE or MDRP infection were prior number of antibiotics; infection site; infection during the previous 3 months; and hospital prevalence of 3GC-R, CRE, or MDRP. To enable application of the six predictive multivariate logistic regression models to real-world clinical practice, we developed a user-friendly interface that estimates the risk of 3GC-R, CRE, and MDRP simultaneously in a given patient with a Gram-negative infection based on their risk (Additional file 1).

Conclusions

We developed a clinical prediction tool to estimate the probabilities of 3GC-R, CRE, and MDRP among hospitalized adult patients with confirmed community- and hospital-acquired Gram-negative infections. Our predictive model has been implemented as a user-friendly bedside tool for use by clinicians/healthcare professionals to predict the probability of resistant infections in individual patients, to guide early appropriate therapy.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4363-y) contains supplementary material, which is available to authorized users.

Risk Factors for Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae Carriage in Patients Admitted to Intensive Care Unit in a Tertiary Care Hospital in Thailand

Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) are important causes of serious infections in intensive care unit (ICU). This study aimed to investigate the risk factors for intestinal carriage of ESBL-PE among patients admitted to ICU, subsequent ESBL-PE infections, and outcomes of these patients. This study prospectively collected rectal swabs from 215 ICU patients in Northern Thailand and ESBL-PE were isolated. A high prevalence of ESBL-PE carriage (134/215, 62.3%) at ICU admission was observed, with Escherichia coli representing the predominant organism (67.5%) followed by Klebsiella pneumoniae (19.4%). Multivariate logistic regression analysis identified chronic renal disease as the independent risk factor for ESBL-PE carriage (p = 0.009; adjusted odds ratio = 4.369; 95% confidence interval = 1.455-13.119). Among colonized patients, 2.2% (3/134) developed ESBL-PE infections during ICU stay. Phylogenetic analysis of E. coli (n = 108) showed that the predominant group was group A (38.0%), followed by groups B1 (17.6%), D (15.7%), B2 (14.8%), C (7.4%), and F (6.5%). Multilocus sequence typing analysis of the pathogenic groups B2, D, and F revealed 11 different sequence types (STs), with ST131 (n = 13) as the most prevalent, followed by ST648 (n = 5), ST38 (n = 4), ST393 (n = 3), and ST1193 (n = 3). These results are of concern since ESBL-PE may be a prerequisite for endogenous infections and potentially disseminate within the hospital. This is the first study describing ESBL-PE carriage among patients at ICU admission and subsequent ESBL-PE infections in Thailand.

Performance of an Easy and Simple New Scoring Model in Predicting Multidrug-Resistant Enterobacteriaceae in Community-Acquired Urinary Tract Infections

Background

Multidrug resistance (MDR) is a growing global problem in bacterial community-acquired urinary tract infections (CUTIs). We aimed to propose an easy-to-use clinical prediction model to identify patients with MDR in CUTI.

Methods

We conducted a retrospective study including 770 patients with documented CUTI diagnosed during 2010–2017. Logistic regression–based prediction scores were calculated based on variables independently associated with MDR. Sensitivities and specificities at various cutoff points were determined, and the area under the receiver operating characteristic curve (AUROC) was computed.

Results

We found MDR Enterobacteriaceae in 372 cases (45.1%). Multivariate analysis showed that age ≥70 years (adjusted odds ratio [aOR], 2.5; 95% confidence interval [CI], 1.8–3.5), diabetes mellitus (aOR, 1.65; 95% CI, 1.19–2.3), history of urinary tract surgery in the last 12 months (aOR, 4.5; 95% CI, 1.22–17), and previous antimicrobial therapy in the last 3 months (aOR, 4.6; 95% CI, 3–7) were independent risk factors of MDR in CUTI. The results of Hosmer-Lemshow chi-square testing were indicative of good calibration of the model (χ² = 3.4; P = .49). At a cutoff of ≥2, the score had an AUROC of 0.71, a sensitivity of 70.5%, a specificity of 60%, a positive predictive value of 60%, a negative predictive value of 70%, and an overall diagnostic accuracy of 65%. When the cutoff was raised to 6, the sensitivity dropped (43%), and the specificity increased appreciably (85%).

Conclusions

We developed a novel scoring system that can reliably identify patients likely to be harboring MDR in CUTI.

ESBL-colonization at ICU admission: impact on subsequent infection, carbapenem-consumption, and outcome

OBJECTIVE

To determine whether colonization with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) predicts the risk for subsequent infection and impacts carbapenem-consumption and outcome in intensive care unit (ICU) patients.

DESIGN

Prospective cohort study.

SETTING

The 2 ICUs in the University Hospital Basel in Switzerland.

PATIENTS

All patients admitted to the 2 ICUs providing mechanical ventilation and an expected ICU stay &gt;48 hours.

METHODS

Patients were routinely screened for ESBL-PE carriage by rectal swab on admission. Competing risk regression analyses were applied to calculate hazard ratios (HRs) for infection with ESBL-PE and mortality. Length of hospital stay, length of ICU stay, and duration of carbapenem exposure were compared using the Mann-Whitney U test.

RESULTS

Among 302 patients, 24 (8.0%) were colonized with ESBL-PE on ICU admission. Infections with ESBL-PE occurred in 4 patients, of whom 3 (75%) were identified as ESBL-PE colonized on admission. ESBL-PE colonization on admission was associated with subsequent ESBL-PE infection (hazard ratio [HR], 25.52; 95% confidence interval [CI], 2.40-271.41; P = .007) and exposure to carbapenems (HR, 2.42; 95% CI, 1.01-5.79; P = .047), whereas duration of carbapenem exposure did not differ in relation to ESBL-PE colonization (median, 7 days [IQR, 3-8 days] vs median, 6 days [IQR 3-9 days]; P = 0.983). Patients colonized with ESBL-PE were not at increased risk for death overall (HR, 1.00; 95% CI, 0.44-2.30; P = .993) or death attributable to infection (HR, 1.20; 95% CI, 0.28-5.11; P = .808).

CONCLUSIONS

Screening strategies for detection of ESBL-PE colonization on ICU admission may allow the identification of patients at highest risk for ESBL-PE infection and the correct allocation of empiric carbapenem treatment.

High prevalence of ESBL-positive bacteria in an obstetrics emergency hospital and neonatal care unit-Haiti, 2016

A point-prevalence survey of mothers and neonates admitted to an obstetrics emergency hospital in Port-au-Prince, Haiti, revealed that 13 of 127 gram-negative bacteria isolates (10%) from rectal swabs were ESBL-positive in women and 30 of 59 gram-negative bacteria isolates (51%) from rectal swabs were ESBL-positive in neonates. Length of hospital stay and antibiotic consumption were risk factors for ESBL colonization.

Reassessing the need for active surveillance of extended-spectrum beta-lactamase-producing Enterobacteriaceae in the neonatal intensive care population

OBJECTIVE

To determine the continued need for active surveillance to prevent extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) transmission in a neonatal intensive care unit (NICU).

DESIGN

This retrospective observational study included patients with ESBL-E colonization or infection identified during their NICU stay at our institution between 1999 and March 2018. Active surveillance was conducted between 1999 and March 2017 by testing rectal swab specimens collected upon admission and weekly thereafter. The overall incidence rates, of ESBL-E colonization or infection (including hospital acquired) before and after active surveillance were calculated. The cost associated with active surveillance was then estimated.

RESULTS

Overall, 171 NICU patients were found to have ESBL-E colonization or infection, and 150 of those patients (87.7%) were detected by active surveillance. The overall incidence rate was 1.4 per 100 patient admissions. The hospital-acquired incidence rate was 0.41 per 1,000 patient days, and this rate had decreased since 2002, with an average of 6 cases detected annually. A significant decrease was observed in 2009 when the unit moved to a new single-bed unit featuring private rooms. Active surveillance was discontinued with no increase in the number of infections. Of the 150 ESBL-E colonized patients, 14 (9.3%) subsequently developed an infection. Active surveillance resulted in a total of 50,950 specimen collections and a cost of $127,187 for processing, an average of $848 to detect 1 ESBL-E colonized patient.

CONCLUSION

ESBL-E transmission and infection in our NICU remains uncommon. Active surveillance may have contributed to the decline of ESBL-E transmission when used in conjunction with contact precautions and private rooms, but its relatively high cost could be prohibitive.

Fecal carriage of carbapenem-resistant Enterobacteriaceae and risk factor analysis in hospitalised patients: A single centre study from India

PURPOSE

Carbapenem-resistant Enterobacteriaceae (CRE) have emerged and disseminated widely causing a variety of infections. In India, the carriage of CRE in hospitalised patients has not been well-studied. Therefore, we conducted the present study to observe gut carriage rate of CRE in patients admitted to our tertiary care hospital.

METHODS

A total of 232 faecal swabs collected from consecutive stool samples from admitted patients were inoculated on ChromID extended spectrum β-lactamase plates and members of Enterobacteriaceae family were subjected to antibiotic susceptibility as per the Clinical Laboratory Standards Institute guidelines. Polymerase chain reaction for blaVIM, blaKPC, blaIMPand blaNDM-1 genes was performed. CRE was identified if the isolates showed resistance to either imipenem or meropenem or showed the presence of resistant genes. Risk factors of patients with or without CRE colonisation were also analysed.

RESULTS

A total of 232 faecal swabs yielded 252 Enterobacteriaceae isolates, of which 49 isolates from 42 patients showed the presence of CRE (occurrence 42/232; 18.1%); 27 isolates from 22 patients carried blaNDM-1, whereas 20 isolates from 17 patients possessed blaVIMgene. No isolate was positive for blaKPCand blaIMPgenes. The CRE was common in both intensive care units (38.4%) and wards (46%) which may reflect the excessive use of broad-spectrum antibiotics in both these settings. The CRE was also found to have a significantly higher antimicrobial resistance as compared to non-CRE isolates. The logistic regression analysis of significance showed the presence of any indwelling device (P = 0.049) and nasogastric tube (P = 0.043) as independent risk factors for acquiring gut colonisation.

CONCLUSIONS

The study is the first from India to show high CRE carriage in patients admitted to a tertiary care centre and emphasises the need of strict antimicrobial stewardship implementation in hospitals to prevent dissemination of multidrug-resistant CRE.

Relationship between digestive tract colonization and subsequent ventilator-associated pneumonia related to ESBL-producing Enterobacteriaceae

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most common ICU-acquired infection. Recently, the incidence of extended-spectrum beta-lactamase producing Enterobacteriaceae (ESBLE) has substantially increased in critically ill patients. Identifying patients at risk for VAP related to ESBLE could be helpful to improve the rate of appropriate initial antibiotic treatment, and to reduce unnecessary exposure to carbapenems. The primary objective was to identify risk factors for VAP related to ESBLE. Secondary objective was to determine the impact of ESBLE on outcome in VAP patients.

METHODS

This retrospective study was conducted in a single mixed intensive care unit (ICU), during a 4-year period. All patients with confirmed VAP were included. VAP was defined using clinical, radiologic and quantitative microbiological data. VAP first episodes were prospectively identified using the continuous surveillance data. Exposure to different risk factors was taken into account until the diagnosis of ESBLE VAP or until ICU discharge, in patients with ESBLE VAP and VAP related to other bacteria, respectively. In all patients, routine screening for ESBLE (rectal swab) was performed at ICU admission and once a week. Patients with ESBLE VAP were compared with those with VAP related to other bacteria using univariate analysis. All significant factors were included in the multivariate logistic regression model.

RESULTS

Among the 410 patients with VAP, 43 (10.5%) had ESBLE VAP, 76 (19%) patients had polymicrobial VAP and 189 (46%) had VAP related to multidrug resistant bacteria. Multivariate analysis identified prior ESBLE colonization of the digestive tract as the only independent risk factor for ESBLE VAP (OR [95% CI] = 23 [10-55], p < 0.001). Whilst the positive predictive value of ESBLE digestive colonization was low (43.6%), its negative predictive value was excellent (97.3%) in predicting ESBLE VAP. Duration of mechanical ventilation (median [IQR], 28 [18,42] vs 23 [15,42] d, p = 0.4), length of ICU stay (31 [19,53] vs 29 [18,46] d, p = 0.6), and mortality rates (55.8% vs 50%, p = 0.48) were similar in ESBLE VAP, compared with VAP related to other bacteria.

CONCLUSION

Digestive tract colonization related to ESBLE is independently associated with ESBLE VAP. Its excellent negative predictive value suggests that patients without ESBLE colonization should not receive carbapenems as part of their initial empirical treatment to cover ESBLE.

Detection of Antimicrobial Susceptibility and Integrons Among Extended-spectrum β-lactamase Producing Uropathogenic Escherichia coli Isolates in Southwestern Iran

Objectives

Urinary tract infections (UTIs) are one of the most prevalent infectious diseases and can lead to a high rate of morbidity and mortality. The emergence of multiple-drug resistant strains, particularly extended-spectrum beta-lactamases (ESBLs) producing strains, has become a global healthcare concern. Our study sought to investigate the antimicrobial resistance pattern and presence of integrons and fimH determinants among uropathogenic Escherichia coli (UPEC) isolates obtained from hospitalized Iranian patients.

Methods

This cross-sectional study was performed on 121 E. coli isolates recovered from patients with clinical symptoms of UTIs, referred to Shiraz Nemazee Hospital, in 2016-17. The isolates were identified by standard microbiologic tests and confirmed by API 20E strip. Antimicrobial susceptibility testing was determined using the disk diffusion method. The presence of fimH and classes 1-3 integron encoding genes was determined using the polymerase chain reaction.

Results

Ampicillin (9.1%) and nalidixic acid (19.0%) showed the lowest level of antibiotic susceptibility. The highest level of susceptibility was toward imipenem (77.7%). The rate of ESBL-producing isolates was 42.1%. There was a significant association between production of ESBLs and higher antibiotic resistance in the tested isolates. Of the investigated virulence and resistance genes, fimH, intI1, and intI2 were positive in 98.3%, 59.5%, and 7.4% of isolates, respectively.

Conclusions

The remarkable rate of ESBL-producing UPEC isolates accompanied with the presence of integrons suggest the necessity of restricted infection control policies to prevent further dissemination of resistant strains.

Assessing the Ability of Hospital Diagnosis Codes to Detect Inpatient Exposure to Antibacterial Agents

OBJECTIVE Because antibacterial history is difficult to obtain, especially when the exposure occurred at an outside hospital, we assessed whether infection-related diagnostic billing codes, which are more readily available through hospital discharge databases, could infer prior antibacterial receipt. DESIGN Retrospective cohort study. PARTICIPANTS This study included 121,916 hospitalizations representing 78,094 patients across the 3 hospitals. METHODS We obtained hospital inpatient data from 3 Chicago-area hospitals. Encounters were categorized as "infection" if at least 1 International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) code indicated a bacterial infection. From medication administration records, we categorized antibacterial agents and calculated total therapy days using Centers for Disease Control and Prevention (CDC) definitions. We evaluated bivariate associations between infection encounters and 3 categories of antibacterial exposure: any, broad spectrum, or surgical prophylaxis. We constructed multivariable models to evaluate adjusted risk ratios for antibacterial receipt. RESULTS Of the 121,916 inpatient encounters (78,094 patients) across the 3 hospitals, 24% had an associated infection code, 47% received an antibacterial, and 13% received a broad-spectrum antibacterial. Infection-related ICD-9-CM codes were associated with a 2-fold increase in antibacterial administration compared to those lacking such codes (RR, 2.29; 95% confidence interval [CI], 2.27-2.31) and a 5-fold increased risk for broad-spectrum antibacterial administration (RR, 5.52; 95% CI, 5.37-5.67). Encounters with infection codes had 3 times the number of antibacterial days. CONCLUSIONS Infection diagnostic billing codes are strong surrogate markers for prior antibacterial exposure, especially to broad-spectrum antibacterial agents; such an association can be used to enhance early identification of patients at risk of multidrug-resistant organism (MDRO) carriage at the time of admission. Infect Control Hosp Epidemiol 2018;39:377-382.

Impact of cephalosporin restriction on incidence of infections with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in an endemic setting

Decreasing cephalosporin use was described as an effective intervention in decreasing the incidence of infections caused by Klebsiella pneumoniae harbouring extended-spectrum beta-lactamase (ESBLKP). Due to sustained increased levels of infections caused by ESBLKP, a multifaceted antibiotic stewardship intervention aimed to decrease cephalosporin use was carried out at a large medical unit of a teaching hospital. All cephalosporins except the first-generation were restricted and could only be prescribed after authorization by an infectious disease physician. The use of cephalosporins decreased significantly after intervention. The effect was most prominent for the third-generation cephalosporins (7.9-1.5 DDD/100 OBD). There was an increase in the consumption of piperacillin/tazobactam, carbapenems and fluoroquinolones. In contrast to our expectations the ESBLKP incidence increased, but the changes were not statistically significant. The intervention was successful in controlling the prescribing of cephalosporins, but had no impact on incidence of ESBLKP infections.

Epidemiology and risk factors for mortality in bloodstream infection by CP-Kp, ESBL-E, Candida and CDI: A single center retrospective study

BACKGROUND

The incidence of C. difficile infection (CDI) and of bloodstream infection (BSI) caused by Candida spp., ESBL-E-producing Enterobacteriaceae (ESBL-E) and carbapenemase-producing K. pneumoniae (CP-Kp) is associated with high mortality.

METHODS

We conducted a single centre retrospective study on patients admitted to Molinette Hospital, Turin, Italy, from January 2013 to April 2015 with CDI or BSI caused by Candida, ESBL-E or CP-Kp. For each patient demographic, clinical and microbiological data were collected. Aims of this study were to describe epidemiology and to evaluate risk factors for in-hospital mortality in this group of patients.

RESULTS

Seven hundred-eighty six cases were analyzed: 398 CDI, 137 candidemia, 125 ESBL-E BSI and 126 CP-Kp BSI. CDI, candidemia and ESBL-E BSI were more frequently reported in internal medicine wards (IMW), whilst CP-Kp were more described in intensive care unit (ICU). Sixty-six percent of patients had a previous hospitalization and the majority of patients had several medical comorbidities. In-hospital death occurred in 23.4%. Independent risk factors for mortality were antibiotic therapy before hospital admission, cardiovascular diseases, neutropenia, urinary catheter, total parenteral nutrition, SIRS and higher creatinine levels at diagnosis. Previous abdominal surgery, inflammatory bowel disease, higher serum albumin levels at the admission and fever at diagnosis were significantly associated with survival.

CONCLUSION

Our data showed that CDI, ESBL-E BSI and candidemia are more frequent in frail patients, admitted to IMW, with chronic comorbidities and broad exposure to antibiotic therapies, with the exception for CP-Kp BSI, still more common in the ICU.

A Systematic Review and Meta-analyses of the Clinical Epidemiology of Carbapenem-Resistant Enterobacteriaceae

Carbapenem-resistant Enterobacteriaceae (CRE) are major health care-associated pathogens and responsible for hospital outbreaks worldwide. To prevent a further increase in CRE infections and to improve infection prevention strategies, it is important to summarize the current knowledge about CRE infection prevention in hospital settings. This systematic review aimed to identify risk factors for CRE acquisition among hospitalized patients. In addition, we summarized the environmental sources/reservoirs and the most successful infection prevention strategies related to CRE. A total of 3,983 potentially relevant articles were identified and screened. Finally, we included 162 studies in the systematic review, of which 69 studies regarding risk factors for CRE acquisition were included in the random-effects meta-analysis studies. The meta-analyses regarding risk factors for CRE acquisition showed that the use of medical devices generated the highest pooled estimate (odds ratio [OR] = 5.09; 95% confidence interval [CI] = 3.38 to 7.67), followed by carbapenem use (OR = 4.71; 95% CI = 3.54 to 6.26). To control hospital outbreaks, bundled interventions, including the use of barrier/contact precautions for patients colonized or infected with CRE, are needed. In addition, it is necessary to optimize the therapeutic approach, which is an important message to infectious disease specialists, who need to be actively involved in a timely manner in the treatment of patients with known CRE infections or suspected carriers of CRE.

Multidrug-Resistant Microorganisms Colonizing Lower Extremity Wounds in Patients in a Tertiary Care Hospital, Lima, Peru

Multidrug-resistant organism (MDRO) infections cause high morbidity and mortality, and high costs to patients and hospitals. The study aims were to determine the frequency of MDRO colonization and associated factors in patients with lower-extremity wounds with colonization. A cross-sectional study was designed during November 2015 to July 2016 in a tertiary care hospital in Lima, Peru. A wound swab was obtained for culture and susceptibility testing. MDRO colonization was defined if the culture grew with methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and/or extended spectrum beta-lactamase (ESBL) microorganisms. The frequency of MDRO wound colonization was 26.8% among the 97 patients enrolled. The most frequent MDRO obtained was ESBL-producing Escherichia coli, which was significantly more frequent in chronic wounds versus acute wounds (17.2% versus 0%, P < 0.05). Infection control measures should be implemented when patients with chronic lower-extremity wounds are admitted.

Should we consider faecal colonisation with extended-spectrum β-lactamase-producing Enterobacteriaceae in empirical therapy of community-onset sepsis?

In patients colonised with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E), the preference for carbapenems (CRBs) over non-CRB antibiotics for empirical therapy of sepsis is questionable from an ecologic perspective. Moreover, how well colonisation predicts an ESBL-E aetiology of infection has been poorly investigated. The purpose of this retrospective observational study was to determine the positive predictive value (PPV) of ESBL-E faecal colonisation for ESBL-E sepsis aetiology and the impact of empirical therapy on treatment outcome. The study included 653 ESBL-E carriers with community-onset sepsis hospitalised at a single medical centre during a 5-year period. The PPV of ESBL-E colonisation for ESBL-E sepsis aetiology was significantly higher (62.6%) when sepsis originated from a urinary tract infection (UTI) than from a respiratory tract infection (24.5%), other known origins (27.1%) or an unidentified origin (21.4%). Among the 653 patients, 177 (27.1%) received CRBs empirically and 476 received non-CRBs, predominantly β-lactam/β-lactamase inhibitor combinations. Although univariate analysis suggested a higher 30-day mortality in the non-CRB versus CRB group (26.7% vs. 19.2%; OR = 1.53; P = 0.049), the estimated association was much smaller and was not significant (OR = 1.11, 95% CI 0.66-1.87; P = 0.68) in the multiple regression analysis adjusted for age, sex, Charlson comorbidity index, and severity, origin or aetiology of sepsis. The subgroup of 240 patients with unidentified sepsis aetiology also did not benefit from empirical CRB treatment. In non-critically ill ESBL-E carriers with community-onset sepsis, CRB-sparing empirical therapy seems appropriate, particularly if sepsis originates from a site other than a UTI.

Evaluating the Impact of Antibiotic Exposures as Time-Dependent Variables on the Acquisition of Carbapenem-Resistant Acinetobacter baumannii

OBJECTIVES

To determine the time-dependent effect of antibiotics on the initial acquisition of carbapenem-resistant Acinetobacter baumannii.

DESIGN

Retrospective cohort study.

SETTING

Forty-bed trauma ICU in Miami, FL.

PATIENTS

All consecutive patients admitted to the unit from November 1, 2010, to November 30, 2011.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients underwent surveillance cultures at admission to the unit and weekly thereafter. The primary outcome was the acquisition of carbapenem-resistant A. baumannii on surveillance cultures. Daily antibiotic exposures during the time of observation were used to construct time-dependent variables, including cumulative exposures (in grams and daily observed doses [defined daily doses]). Among 360 patients, 45 (12.5%) became colonized with carbapenem-resistant A. baumannii. Adjusted Cox models showed that each additional point in the Acute Physiologic and Chronic Health Evaluation score increased the hazard by 4.8% (hazard ratio, 1.048; 95% CI, 1.010-1.087; p = 0.0124) and time-dependent exposure to carbapenems quadrupled the hazard (hazard ratio, 4.087; 95% CI, 1.873-8.920; p = 0.0004) of acquiring carbapenem-resistant A. baumannii. Additionally, adjusted Cox models determined that every additional carbapenem defined daily dose increased the hazard of acquiring carbapenem-resistant A. baumannii by 5.1% (hazard ratio, 1.051; 95% CI, 1.007-1.093; p = 0.0243).

CONCLUSIONS

Carbapenem exposure quadrupled the hazards of acquiring A. baumannii even after controlling for severity of illness.

Sites of colonization in hospitalized patients with infections caused by extended-spectrum beta-lactamase organisms: a prospective cohort study

Background

The objective of this study was to determine whether patients infected with extended-spectrum beta-lactamase (ESBL)-producing organisms are colonized at multiple body sites.

Methods

This was a prospective cohort study at a tertiary care center in Beirut, Lebanon. Hospitalized patients with infections caused by ESBL-producing organisms were included. Cultures were obtained from the primary site of infection as well as from other sites (skin, nasopharynx, urine, rectum). Molecular analysis was performed on isolates to determine clonal relatedness.

Results

One hundred patients were included in the study. Only 22 patients had positive cultures from sites other than the primary site of infection. The most common ESBL gene was CTX-M-15 followed by TEM-1. In 11 of 22 patients, isolates collected from the same patient were 100% genetically related, while in the remaining patients, genomic relatedness ranged from 42.9% to 97.1%.

Conclusions

Colonization at sites other than the primary site of infection was not common among our patient population infected with ESBL-producing organisms. The dynamics of transmission of these bacterial strains should be studied in further prospective studies to determine the value of routine active surveillance and the need for expanded precautions in infected and colonized patients.

Best Practices in the Management of Infectious Complications for Patients With Cancer

As antibiotic resistant bacteria are becoming ubiquitous, managing infection becomes more complex. Optimizing preventive measures, early diagnosis, and management of infection is of the highest priority in cancer care.

Efficacy and acceptability of rectal and perineal sampling for identifying gastrointestinal colonization with extended spectrum β-lactamase Enterobacteriaceae

OBJECTIVES

We evaluated 'pre-laboratory' factors associated with the detection of extended spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) colonization including anatomical site, and staff and patient factors.

METHODS

All admissions to a large London hospital over 3 months were approached to provide rectal and perineal swabs, which were cultured for ESBL-E using chromogenic media. ESBL-E detection rates for patient- or staff-collected rectal or perineal swabs were compared using McNemar tests. Binary logistic regression was used to explore factors associated with patients declining to provide a rectal swab. The impact of simplifying the verbal study description to patients to improve the participation rate was evaluated.

RESULTS

Carriage of ESBL-E was significantly higher in rectal swabs than perineal swabs (7.8% of 4006 versus 3.8% of 4006, p <0.001), whether collected by staff or patients; 31.9% of 869 patients did not provide a rectal swab before the change in study description compared with 7.6% of 3690 patients afterwards (p <0.001). In multivariable analysis, factors associated with patients declining to provide a rectal swab were younger age (OR 0.99, 95% CI 0.99-1.00), female gender (OR 1.26, 95% CI 1.04-1.52), transfers from other hospitals (OR 1.77, 95% CI 1.07-2.93) or an unknown admission route (OR 1.61, 95% CI 1.09-2.37), being admitted before the change in study description (OR 0.39, 95% CI 0.31-0.48), and the staff member who consented the patient (p <0.001); ethnicity was not a significant factor.

CONCLUSIONS

Rectal swabs are recommended for the detection of ESBL-E colonization. Staff and patient factors influence whether patients participate in prevalence studies, which may skew their findings.

Gut bacteria and late-onset neonatal bloodstream infections in preterm infants

Late-onset neonatal bloodstream infections remain challenges in neonatology. Hand hygiene, line care, and judicious use of indwelling lines are welcome interventions, but might not reduce the incidence of late-onset neonatal bloodstream infections from bacteria originating in the gut. Accumulating data suggest that many pathogens causing late-onset neonatal bloodstream infections are of gut origin, including Gram-positive cocci. In addition to the host-canonical paradigm (i.e., all bacteria have equal risk of invasion and bloodstream infections are functions of variable infant susceptibility), we should now consider bacteria-canonical paradigms, whereby late-onset neonatal bloodstream infection is a function of colonization with a specific subset of bacteria with exceptional invasive potential. In either event, we can no longer be content to reactively approach late-onset neonatal bloodstream infections; instead we need to reduce the occurrences of these infections by broadening our scope of effort beyond line care, and determine the pre-invasive habitat of these pathogens.

Aerobic bacterial profile and antibiotic resistance in patients with diabetic foot infections

INTRODUCTION

This study aimed to determine the frequencies of bacterial isolates cultured from diabetic foot infections and assess their resistance and susceptibility to commonly used antibiotics.

METHODS

This prospective study included 41 patients with diabetic foot lesions. Bacteria were isolated from foot lesions, and their antibiotic susceptibility pattern was determined using the Kirby-Bauer disk diffusion method and/or broth method [minimum inhibitory concentration (MIC)].

RESULTS

The most common location of ulceration was the toe (54%), followed by the plantar surface (27%) and dorsal portion (19%). A total of 89 bacterial isolates were obtained from 30 patients. The infections were predominantly due to Gram-positive bacteria and polymicrobial bacteremia. The most commonly isolated Gram-positive bacteria were Staphylococcus aureus, followed by Staphylococcus saprophyticus, Staphylococcus epidermidis, Streptococcus agalactiae, and Streptococcus pneumoniae. The most commonly isolated Gram-negative bacteria were Proteus spp. and Enterobacterspp., followed by Escherichia coli, Pseudomonasspp., and Citrobacterspp. Nine cases of methicillin-resistant Staphylococcus aureus (MRSA) had cefoxitin resistance, and among these MRSA isolates, 3 were resistant to vancomycin with the MIC technique. The antibiotic imipenem was the most effective against both Gram-positive and Gram-negative bacteria, and gentamicin was effective against Gram-negative bacteria.

CONCLUSIONS

The present study confirmed the high prevalence of multidrug-resistant pathogens in diabetic foot ulcers. It is necessary to evaluate the different microorganisms infecting the wound and to know the antibiotic susceptibility patterns of the isolates from the infected wound. This knowledge is crucial for planning treatment with the appropriate antibiotics, reducing resistance patterns, and minimizing healthcare costs.

Asymptomatic faecal carriage of ESBL producing enterobacteriaceae in Hungarian healthy individuals and in long-term care applicants: A shift towards CTX-M producers in the community

Background Faecal carriage of extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae in healthy individuals was examined and compared to previous results obtained in such individuals a few years earlier. Methods Faecal samples from 779 individuals screened for employment purposes and from 225 applicants to long-term care (LTC) were screened between November 2013 and May 2014. Results The overall rate of faecal carriage was 3.0% (30/1004). The carriage rate was significantly higher in applicants for LTC (5.3% vs 2.3%; p = 0.019). All isolates carried CTX-M ESBLs, with an overwhelming dominance of blaCTX-M-15 (84.4%) in both groups and in both E. coli and Klebsiella pneumoniae. Conclusions The prevalences were comparable to those in the earlier study, but a marked decrease of the diversity of ESBL genes in E. coli from the employment screening group was found, suggesting that the ESBL-producing isolates originating from diverse sources are being replaced by highly successful blaCTX-M-15 producing strains.

Colonization and infection with extended-spectrum β-lactamase-producing Enterobacteriaceae in ICU patients: what impact on outcomes and carbapenem exposure?

OBJECTIVES

It remains uncertain whether colonization and infection with ESBL-producing Enterobacteriaceae (ESBL-PE) affect the outcomes for ICU patients. Our objectives were to measure the effects of ESBL-PE carriage and infection on mortality, ICU length of stay (LOS) and carbapenem exposure in this population.

METHODS

A cause-specific hazard model based on prospectively collected data was built to assess the impact of ESBL-PE colonization and infection on competing risks of death and ICU discharge at day 28 in a multicentre cohort of ICU patients. Carbapenem exposure during the ICU stay was compared between infected carriers, uninfected carriers and non-carriers.

RESULTS

Among the 16,734 included patients, 594 (3.5%) were ESBL-PE carriers, including 98 (16.4%) with one or more ESBL-PE infections during the ICU stay. After adjustment for baseline and time-dependent confounders, ESBL-PE infections increased the probability of death at day 28 [adjusted cause-specific hazard ratio (aCSHR), 1.825, 95% CI 1.235-2.699, P = 0.0026] and the ICU LOS (aCSHR for discharge alive at day 28, 0.563, 95% CI 0.432-0.733, P < 0.0001). ESBL-PE carriage without infection extended the LOS (aCSHR, 0.623, 95% CI, 0.553-0.702, P < 0.0001), without affecting mortality (aCSHR, 0.906, 95% CI, 0.722-1.136, P = 0.3916). Carbapenem exposure increased in both infected and uninfected carriers when compared with non-carriers (627, 241 and 69 carbapenem days per 1000 patient days, respectively, P < 0.001).

CONCLUSIONS

ESBL-PE infections increased carbapenem consumption, LOS and day 28 mortality. ESBL-PE infections were rather infrequent in carriers; however, even ESBL-PE carriage without infection increased carbapenem exposure and delayed discharge, thereby amplifying the selective pressure and the colonization pressure in the ICU.