Bacterial Etiology and Antimicrobial Resistance Pattern of Pediatric Bloodstream Infections in Beijing, 2015-2019

Purpose

Bloodstream infections (BSIs) was an essential cause of morbidity and mortality in children. Empiric broad-spectrum treatment of BSIs may be costly and unable to effectively eliminate the correct pathogenic microbes, resulting in downstream antimicrobial resistance. The purpose was to provide evidence for diagnosis and treatment of bloodstream infections in pediatrics, by revealing the pathogen distribution and antibiotic resistance pattern of BSIs.

Methods

In this 5-year study, a total of 2544 pathogenic bacteria stains, isolated from 2368 patients with BSI, were retrospectively analyzed, to define the species distribution and the antimicrobial resistance pattern in Beijing.

Results

The most frequently isolated pathogenic bacteria were K. pneumoniae (12.1%), S. aureus (11.5%), E. coli (11.2%), and E. faecium (11.2%). Hematological malignancies were the most common disease among patients with underlying conditions. Methicillin resistance was detected in 30.0% of S. aureus and 81.7% of coagulase-negative Staphylococcus (CoNS), respectively. The detection rates of carbapenem-resistant-E. coli (CRECO) and carbapenem-resistant-K. pneumoniae (CRKPN) were 10.8% and 50.8%, respectively. In terms of 122 isolates of S. pneumonia, 5 isolates (4.1%) were penicillin-resistant Streptococcus pneumoniae (PRSP); meanwhile, 50 isolates (41.0%) were penicillin-intermediate Streptococcus pneumoniae (PISP). Among the non-fermentative gram-negative bacilli isolates, 22.8% and 26.9% of the P. aeruginosa, were resistant to imipenem and meropenem. Furthermore, the resistance rates of A. baumannii to imipenem and meropenem both were 54.5%.

Conclusion

In the study, we demonstrated the characteristics of bloodstream infections and antimicrobial susceptibility pattern of pediatrics in Beijing. Gram positive bacteria were the main pathogens of BSIs. CoNS strains presented even higher resistance to multiple antibiotics, including methicillin, than S. aureus. K. pneumoniae and E. coli represent the most common isolated gram-negative bacteria and exhibited high resistance to a variety of antimicrobial agents. Therefore, it was of critical importance to implement appropriate antimicrobial medication according to pathogen distribution and drug susceptibility test.

Transmission of Carbapenem-Resistant Enterobacterales in an Overcrowded Emergency Department: Controlling the Spread to the Hospital

BACKGROUND

Overcrowded emergency departments (EDs) may increase the risk of carbapenem-resistant Enterobacterales (CRE) transmission.

METHODS

We conducted a quasi-experimental study divided into 2 phases (baseline and intervention) to investigate the impact of an intervention on the acquisition rate and identify risk factors for CRE colonization in an ED of a tertiary academic hospital in Brazil. In both phases, we did universal screening with rapid molecular test (blaKPC, blaNDM, blaOXA48, blaOXA23, and blaIMP) and culture. At baseline, both screening test results were not reported, and patients were put under contact precautions (CP) based on previous colonization or infection by multidrug-resistant organisms. During the intervention, all patients hospitalized in the ED were placed in empiric CP and the result of CRE screening was reported; if negative, patients were released from CP. Patients were rescreened if they stayed >7 days in the ED or were transferred to an intensive care unit.

RESULTS

A total of 845 patients were included: 342 in baseline and 503 in intervention. Colonization at admission was 3.4% by culture and molecular test. Acquisition rates during ED stay dropped from 4.6% (11/241) to 1% (5/416) during intervention (P = .06). The aggregated antimicrobial use in the ED decreased from phase 1 to phase 2 (804 defined daily doses [DDD]/1000 patients to 394 DDD/1000 patients, respectively). Length of stay >2 days in the ED was a risk factor for CRE acquisition (adjusted odds ratio, 4.58 [95% confidence interval, 1.44-14.58]; P = .01).

CONCLUSIONS

Early empiric CP and rapid identification of CRE-colonized patients reduce cross-transmission in ED. Nevertheless, staying >2 days in ED compromised efforts.

An interventional quasi-experimental study to evaluate the impact of a rapid screening strategy in improving control of nosocomial extended-spectrum beta-lactamase-producing Enterobacterales and carbapenemase-producing organisms in critically ill patients

Introduction

Rapid molecular tests could accelerate the control of extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and carbapenemase-producing organisms (CPO) in intensive care units (ICUs).

Objective and methods

This interventional 12-month cohort study compared a loop-mediated isothermal amplification (LAMP) assay performed directly on rectal swabs with culturing methods (control period, 6 months), during routine ICU screening. Contact precautions (CP) were implemented for CPO or non-E. coli ESBL-producing Enterobacterales (nEcESBL-PE) carriers. Using survival analysis, we compared the time intervals from admission to discontinuation of unnecessary preemptive CP among patients at-risk and the time intervals from screening to implementation of CP among newly identified carriers. We also compared diagnostic performances, and nEcESBL-PE/CPO acquisition rates. This study is registered, ISRCTN 23588440.

Results

We included 1043 patients. During the intervention and control phases, 92/147 (62.6%) and 47/86 (54.7%) of patients at-risk screened at admission were candidates for early discontinuation of preemptive CP. The LAMP assay had a positive predictive value (PPV) of 44.0% and a negative predictive value (NPV) of 99.9% for CPO, and 55.6% PPV and 98.2% NPV for nEcESBL-PE. Due to result notification and interpretation challenges, the median time from admission to discontinuation of preemptive CP increased during the interventional period from 80.5 (95% CI 71.5–132.1) to 88.3 (95% CI 57.7–103.7) hours (p = 0.47). Due to the poor PPV, we had to stop using the LAMP assay to implement CP. No difference was observed regarding the incidence of nEcESBL-PE and CPO acquisition.

Conclusion

A rapid screening strategy with LAMP assays performed directly on rectal swabs had no benefit for infection control in a low-endemicity setting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04027-8.

Attributable Length of Stay, Mortality Risk, and Costs of Bacterial Health Care-Associated Infections in Australia: A Retrospective Case-cohort Study

Background

Unbiased estimates of the health and economic impacts of health care–associated infections (HAIs) are scarce and focus largely on patients with bloodstream infections (BSIs). We sought to estimate the hospital length of stay (LOS), mortality rate, and costs of HAIs and the differential effects on patients with an antimicrobial-resistant infection.

Methods

We conducted a multisite, retrospective case-cohort of all acute-care hospital admissions with a positive culture of 1 of the 5 organisms of interest (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, or Enterococcus faecium) from 1 January 2012 through 30 December 2016. Data linkage was used to generate a data set of statewide hospital admissions and pathology data. Patients with bloodstream, urinary, or respiratory tract infections were included in the analysis and matched to a sample of uninfected patients. We used multistate survival models to generate LOS, and logistic regression to derive mortality estimates.

Results

We matched 20 390 cases to 75 635 uninfected control patients. The overall incidence of infections due to the 5 studied organisms was 116.9 cases per 100 000 patient days, with E. coli urinary tract infections (UTIs) contributing the largest proportion (51 cases per 100 000 patient days). The impact of a UTI on LOS was moderate across the 5 studied pathogens. Resistance significantly increased LOS for patients with third-generation cephalosporin-resistant K. pneumoniae BSIs (extra 4.6 days) and methicillin-resistant S. aureus BSIs (extra 2.9 days). Consequently, the health-care costs of these infections were higher, compared to corresponding drug-sensitive strains.

Conclusions

The health burden remains highest for BSIs; however, UTIs and respiratory tract infections contributed most to the health-care system expenditure.

The healthcare costs of antimicrobial resistance in Lebanon: a multi-centre prospective cohort study from the payer perspective

Background

Our aim was to examine whether the length of stay, hospital charges and in-hospital mortality attributable to healthcare- and community-associated infections due to antimicrobial-resistant bacteria were higher compared with those due to susceptible bacteria in the Lebanese healthcare settings using different methodology of analysis from the payer perspective .

Methods

We performed a multi-centre prospective cohort study in ten hospitals across Lebanon. The sample size consisted of 1289 patients with documented healthcare-associated infection (HAI) or community-associated infection (CAI). We conducted three separate analysis to adjust for confounders and time-dependent bias: (1) Post-HAIs in which we included the excess LOS and hospital charges incurred after infection and (2) Matched cohort, in which we matched the patients based on propensity score estimates (3) The conventional method, in which we considered the entire hospital stay and allocated charges attributable to CAI. The linear regression models accounted for multiple confounders.

Results

HAIs and CAIs with resistant versus susceptible bacteria were associated with a significant excess length of hospital stay (2.69 days [95% CI,1.5–3.9]; p < 0.001) and (2.2 days [95% CI,1.2–3.3]; p < 0.001) and resulted in additional hospital charges ($1807 [95% CI, 1046–2569]; p < 0.001) and ($889 [95% CI, 378–1400]; p = 0.001) respectively. Compared with the post-HAIs analysis, the matched cohort method showed a reduction by 26 and 13% in hospital charges and LOS estimates respectively. Infections with resistant bacteria did not decrease the time to in-hospital mortality, for both healthcare- or community-associated infections. Resistant cases in the post-HAIs analysis showed a significantly higher risk of in-hospital mortality (odds ratio, 0.517 [95% CI, 0.327–0.820]; p = 0.05).

Conclusion

This is the first nationwide study that quantifies the healthcare costs of antimicrobial resistance in Lebanon. For cases with HAIs, matched cohort analysis showed more conservative estimates compared with post-HAIs method. The differences in estimates highlight the need for a unified methodology to estimate the burden of antimicrobial resistance in order to accurately advise health policy makers and prioritize resources expenditure.

Pilot study of a combined genomic and epidemiologic surveillance program for hospital-acquired multidrug-resistant pathogens across multiple hospital networks in Australia

OBJECTIVES

To conduct a pilot study implementing combined genomic and epidemiologic surveillance for hospital-acquired multidrug-resistant organisms (MDROs) to predict transmission between patients and to estimate the local burden of MDRO transmission.

DESIGN

Pilot prospective multicenter surveillance study.

SETTING

The study was conducted in 8 university hospitals (2,800 beds total) in Melbourne, Australia (population 4.8 million), including 4 acute-care, 1 specialist cancer care, and 3 subacute-care hospitals.

METHODS

All clinical and screening isolates from hospital inpatients (April 24 to June 18, 2017) were collected for 6 MDROs: vanA VRE, MRSA, ESBL Escherichia coli (ESBL-Ec) and Klebsiella pneumoniae (ESBL-Kp), and carbapenem-resistant Pseudomonas aeruginosa (CRPa) and Acinetobacter baumannii (CRAb). Isolates were analyzed and reported as routine by hospital laboratories, underwent whole-genome sequencing at the central laboratory, and were analyzed using open-source bioinformatic tools. MDRO burden and transmission were assessed using combined genomic and epidemiologic data.

RESULTS

In total, 408 isolates were collected from 358 patients; 47.5% were screening isolates. ESBL-Ec was most common (52.5%), then MRSA (21.6%), vanA VRE (15.7%), and ESBL-Kp (7.6%). Most MDROs (88.3%) were isolated from patients with recent healthcare exposure.Combining genomics and epidemiology identified that at least 27.1% of MDROs were likely acquired in a hospital; most of these transmission events would not have been detected without genomics. The highest proportion of transmission occurred with vanA VRE (88.4% of patients).

CONCLUSIONS

Genomic and epidemiologic data from multiple institutions can feasibly be combined prospectively, providing substantial insights into the burden and distribution of MDROs, including in-hospital transmission. This analysis enables infection control teams to target interventions more effectively.

Epidemiology, Risk Factors, and Clinical Outcomes of Bloodstream Infection due to Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae in Hematologic Malignancy: A Retrospective Study from Central South China

Objective: To determine the epidemiology, risk factors, and prognosis of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae bloodstream infections (BSIs) among hematology malignancy (HM) patients in China. Method: From January 2010 to June 2018, we retrospectively collected and analyzed the 449 HM patients with E. coli or K. pneumoniae BSIs from three leading hospitals in Hunan Province, China. Results: Two hundred four (45.4%) patients harbored ESBL-producing bacteremia. The proportion of ESBL-producing bacteremia increased significantly with the growth of the year, with a ratio of 34.47% in 2010-2014 to 54.7% in 2015-2018. Comparing with non-ESBL groups in HM patients, central venous catheter (odds ratio [OR] 1.717, p = 0.009), previous antibiotic exposure (OR 1.559, p = 0.035), and E. coli (OR 2.561, p ≤ 0.001) among ESBL groups were independent risk factors. No significant differences in 30-day mortality were tested in patients with BSI caused by ESBL-producing or non-ESBL-producing E. coli and K. pneumoniae (17.1% vs. 16.7%; p = 0. 893). The proportion of carbapenem used within 72 hours after the onset of bacteremia in two groups was high, which was routinely used as "last-resort drugs" in Gram-negative bacterial infections. Risk factors associated with 30-day mortality in HM patients with E. coli or K. pneumoniae bacteremia were myelodysplastic syndrome, incomplete remission of the disease, Multinational Association of Supportive Care in Cancer score <21, Pitt bacteremia score ≥4, Charlson comorbidity score >3, catheter insertion, use of vasopressors, and inappropriate antibiotics within 72 hours of BSI onset. Conclusions: The results of this study may provide some references for the whole process management of HM patients with BSIs.

Economic Burden of Patients with Bloodstream Infections Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli

Background

The prevalence of infections with extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) is increasing worldwide, but the economic impact of ESBL-EC bloodstream infection (BSI) has not been comprehensively evaluated.

Patients and Methods

A retrospective cohort including patients hospitalized at a tertiary hospital between January 2013 and December 2016 who were confirmed with a BSI of ESBL-EC or non-ESBL-EC was set. Clinical data and medical costs were collected by chart review of electronic and paper medical records. The economic burden was evaluated with disability-adjusted life years (DALYs).

Results

A total of 580 patients with E. coli BSI, comprising 333 patients (57.4%) with ESBL-EC BSI and 247 patients (42.6%) with non-ESBL-EC BSI, were identified. There were no significant differences in comorbidity and severity of patients between ESBL-EC and non-ESBL-EC BSI. The median length of stay (LOS) after bacteremia was 12 days for ESBL-EC (interquartile range, 7 to 21) versus 11 days for non-ESBL-EC (interquartile range, 7 to 21) (P = 0.38), and appropriate empirical antimicrobial therapy occurred in 87.4% versus 89.9% (P = 0.353). The mortalities were 20.1% versus 17.4% (P = 0.41). Patients with ESBL-EC did not have significantly different in-hospital medical costs to those with non-ESBL-EC (median, $8048.68 vs $7476.84, respectively, with a difference of $571.84, P = 0.321). In the non-ESBL-EC group, 247 patients lost 531.05 DALYs in total, with an average of 2.15 DALYs per person, while in the ESBL-EC group, 333 patients lost 692.64 DALYs in total, with an average of 2.08 DALYs per person. There is no significant difference in average DALYs (P = 0.343).

Conclusion

In conclusion, patients with BSI due to ESBL-EC did not cost more than patients with BSI due to non-ESBL-EC. This phenomenon may be attributed to timely and effective antibiotic treatment, but the initial empiric therapy with second- or third-line antibiotics in non-ESBL-EC BSI should be corrected.

Metagenomic Characterization of Gut Microbiota of Carriers of Extended-Spectrum Beta-Lactamase or Carbapenemase-Producing Enterobacteriaceae Following Treatment with Oral Antibiotics and Fecal Microbiota Transplantation: Results from a Multicenter Randomized Trial

Background: The R-GNOSIS (Resistance in Gram-Negative Organisms: Studying Intervention Strategies) WP3 study was the first multicenter randomized clinical trial systematically investigating fecal microbiota transplantation (FMT) for intestinal decolonization of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) or carbapenemase-producing Enterobacteriaceae (CPE). Here, we characterized the temporal dynamics of fecal microbiota changes in a sub-cohort of the R-GNOSIS WP3 participants before and after antibiotics/FMT using whole metagenome shotgun sequencing. Methods: We sequenced fecal DNA obtained from 16 ESBL-E/CPE carriers having received oral colistin/neomycin followed by FMT and their corresponding seven donors. Ten treatment-naïve controls from the same trial were included. Fecal samples were collected at baseline (V0), after antibiotics but before FMT (V2) and three times after FMT (V3, V4 and V5). Results: Antibiotic treatment transiently decreased species richness and diversity and increased the abundance of antibiotic resistance determinants (ARDs). Bifidobacterium species, together with butyrate- and propionate-producing species from Lachnospiraceae and Ruminococcaceae families were significantly enriched in post-FMT microbiota of treated carriers. After FMT, the proportion of Enterobacteriaceae was lower compared to baseline but without statistical significance. Conclusions: Combined antibiotic and FMT treatment resulted in enrichment of species that are likely to limit the gut colonization by ESBL-E/CPE.

External Societal Costs of Antimicrobial Resistance in Humans Attributable to Antimicrobial Use in Livestock

Antimicrobial use (AMU) in animal agriculture contributes to antimicrobial resistance (AMR) in humans, which imposes significant health and economic costs on society. Economists call these costs negative externalities, societal costs that are not properly reflected in market prices. We review the relevant literature and develop a model to quantify the external costs of AMU in animal agriculture on AMR in humans. Parameters required for this estimate include (a) the health and economic burden of AMR in humans,(b) the impact of AMU in animal agriculture on AMR in animals, (c) the fraction of AMR in humans attributable to animal agriculture, and (d) AMU in animals. We use a well-documented historic case to estimate an externality cost of about US$1,500 per kilogram of fluoroquinolones administered in US broiler chicken production. Enhanced data collection, particularly on the third and fourth parameters, is urgently needed to quantify more fully the externalities of AMU in animal agriculture.

Excess Length of Acute Inpatient Stay Attributable to Acquisition of Hospital-Onset Gram-Negative Bloodstream Infection with and without Antibiotic Resistance: A Multistate Model Analysis

Excess length of stay (LOS) is an important outcome when assessing the burden of nosocomial infection, but it can be subject to survival bias. We aimed to estimate the change in LOS attributable to hospital-onset (HO) Escherichia coli/Klebsiella spp. bacteremia using multistate models to circumvent survival bias. We analyzed a cohort of all patients with HO E.coli/Klebsiella spp. bacteremia and matched uninfected control patients within the U.S. Veterans Health Administration System in 2003–2013. A multistate model was used to estimate the change in LOS as an effect of the intermediate state (HO-bacteremia). We stratified analyses by susceptibilities to fluoroquinolones (fluoroquinolone susceptible (FQ-S)/fluoroquinolone resistant (FQ-R)) and extended-spectrum cephalosporins (ESC susceptible (ESC-S)/ESC resistant (ESC-R)). Among the 5964 patients with HO bacteremia analyzed, 957 (16.9%) and 1638 (28.9%) patients had organisms resistant to FQ and ESC, respectively. Any HO E.coli/Klebsiella bacteremia was associated with excess LOS, and both FQ-R and ESC-R were associated with a longer LOS than susceptible strains, but the additional burdens attributable to resistance were small compared to HO bacteremia itself (FQ-S: 12.13 days vs. FQ-R: 12.94 days, difference: 0.81 days (95% CI: 0.56–1.05), p < 0.001 and ESC-S: 11.57 days vs. ESC-R: 16.56 days, difference: 4.99 days (95% CI: 4.75–5.24), p < 0.001). Accurate measurements of excess attributable LOS associated with resistance can help support the business case for infection control interventions.

Extended spectrum β-lactamase producing enterobacteriaceae: carbapenem sparing options

Introduction: Carbapenems have an important place in our antibiotic armamentarium and have been trusted to effectively treat infections caused by ESBL-producing Enterobacteriaceae for many years. However, the utility of carbapenems has been compromised by the emergence of resistance especially in Enterobacteriaceae. Therefore, carbapenem-sparing alternative antibiotics are of extreme importance in clinical practice.Areas covered: We reviewed studies addressing currently available antibiotic options used as both empiric and definitive therapy for the treatment of infections due to ESBL-producing Enterobacteriaceae published in the PubMed/MEDLINE, Web of Science and Scopus databases without any date restriction. Current treatment alternatives included beta-lactam/beta-lactamase inhibitor combinations, cefepime, cephamycins, fluoroquinolones, aminoglycosides, fosfomycin, pivmecillinam, temocillin and, various oral alternative agents. We also summarized the clinical and molecular epidemiology, early prediction methods and impact of initial empirical therapy and de-escalation approach for ESBL-producing Enterobacteriaceae infections.Expert opinion: The current literature would endorse the carbapenem utilization for patients with severe and high inoculum-high risk infections. However, for milder infections particularly for urinary tract infections, various carbapenem-sparing antibiotics can be considered in selected cases. For infections including easily drainable intra-abdominal infections and catheter-related infections in which catheter removal is readily available more reliable data are needed to recommend non-carbapenem antibiotics confidently.

Burden of bacterial bloodstream infection-a brief update on epidemiology and significance of multidrug-resistant pathogens

BACKGROUND

Bloodstream infections comprise a wide variety of pathogens and clinical syndromes with considerable overlap with similar syndromes of non-bacteraemic infections and diverse risk factors, therapeutic implications and outcomes. Yet, this heterogeneous 'entity' has the advantage to be pathogen-defined compared with the broad and even more heterogeneous entity 'sepsis', and so has become helpful for clinicians and epidemiologists for research and surveillance purposes. The increasing availability of population-based and large multicentre well-defined cohort studies should allow us to assess with much confidence and in detail its burden, the significance of antimicrobial resistance, and areas of uncertainty regarding further epidemiological evolution and optimized treatment regimens.

AIM

To review key aspects of bloodstream infection epidemiology and burden, and summarize recent news and questions concerning critical developments.

SOURCES

Peer-reviewed articles based on the search terms 'bloodstream infection' and 'bacteremia' combined with the terms 'epidemiology' and 'burden'. The emphasis was on new information from studies in adult patients and on the added burden due to pathogen resistance to first- and second-line antimicrobial agents.

CONTENT

Topics covered include recent developments in the epidemiology of bloodstream infection due to key pathogens and published information about the relevance of resistance for patient outcomes.

IMPLICATIONS

Despite the availability of population-based studies and an increasing number of large well-defined multicentre cohort studies, more surveillance and systematic data on bloodstream infection epidemiology at regional level and in resource-limited settings may be needed to better design new methods for prevention and define the need for and further develop optimized therapeutic strategies.

The health and cost burden of antibiotic resistant and susceptible Escherichia coli bacteraemia in the English hospital setting: A national retrospective cohort study

INTRODUCTION

Antibiotic resistance poses a threat to public health and healthcare systems. Escherichia coli causes more bacteraemia episodes in England than any other bacterial species. This study aimed to estimate the burden of E. coli bacteraemia and associated antibiotic resistance in the secondary care setting.

MATERIALS AND METHODS

This was a retrospective cohort study, with E. coli bacteraemia as the main exposure of interest. Adult hospital in-patients, admitted to acute NHS hospitals between July 2011 and June 2012 were included. English national surveillance and administrative datasets were utilised. Cox proportional hazard, subdistribution hazard and multistate models were constructed to estimate rate of discharge, rate of in-hospital death and excess length of stay, with a unit bed day cost applied to the latter to estimate cost burden from the healthcare system perspective.

RESULTS

14,042 E. coli bacteraemia and 8,919,284 non-infected inpatient observations were included. E. coli bacteraemia was associated with an increased rate of in-hospital death across all models, with an adjusted subdistribution hazard ratio of 5.88 (95% CI: 5.62-6.15). Resistance was not found to be associated with in-hospital mortality once adjusting for patient and hospital covariates. However, resistance was found to be associated with an increased excess length of stay. This was especially true for third generation cephalosporin (1.58 days excess length of stay, 95% CI: 0.84-2.31) and piperacillin/tazobactam resistance (1.23 days (95% CI: 0.50-1.95)). The annual cost of E. coli bacteraemia was estimated to be £14,346,400 (2012 £), with third-generation cephalosporin resistance associated with excess costs per infection of £420 (95% CI: 220-630).

CONCLUSIONS

E. coli bacteraemia places a statistically significant burden on patient health and the hospital sector in England. Resistance to front-line antibiotics increases length of stay; increasing the cost burden of such infections in the secondary care setting.

Costs of hospital-acquired Clostridium difficile infections: an analysis on the effect of time-dependent exposures using routine and surveillance data

Background

Hospital-acquired infections have not only gained increasing attention clinically, but also methodologically, as a time-varying exposure. While methods to appropriately estimate extra length of stay (LOS) have been established and are increasingly used in the literature, proper estimation of cost figures has lagged behind.

Methods

Analysing the additional costs and reimbursements of Clostridium difficile-infections (CDI), we use a within-main-diagnosis-time-to-exposure stratification approach to incorporate time-varying exposures in a regression model, while at the same time accounting for cost clustering within diagnosis groups.

Results

We find that CDI is associated with €9000 of extra costs, €7800 of higher reimbursements, and 6.4 days extra length of stay. Using a conventional method, which suffers from time-dependent bias, we derive estimates more than three times as high (€23,000, €8000, 21 days respectively). We discuss our method in the context of recent methodological advances in the estimation of the costs of hospital-acquired infections.

Conclusions

CDI is associated with sizeable in-hospital costs. Neglecting the methodological particularities of hospital-acquired infections can however substantially bias results. As the data needed for an appropriate analysis are collected routinely in most hospitals, we recommend our approach as a feasible way for estimating the economic impact of time-varying adverse events during hospital stay.

Using the best available data to estimate the cost of antimicrobial resistance: a systematic review

Background

Valuation of the economic cost of antimicrobial resistance (AMR) is important for decision making and should be estimated accurately. Highly variable or erroneous estimates may alarm policy makers and hospital administrators to act, but they also create confusion as to what the most reliable estimates are and how these should be assessed. This study aimed to assess the quality of methods used in studies that quantify the costs of AMR and to determine the best available evidence of the incremental cost of these infections.

Methods

In this systematic review, we searched PubMed, Embase, Cinahl, Cochrane databases and grey literature sources published between January 2012 and October 2016. Articles reporting the additional burden of Enterococcus spp., Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) resistant versus susceptible infections were sourced. The included studies were broadly classified as reporting oncosts from the healthcare/hospital/hospital charges perspective or societal perspective. Risk of bias was assessed based on three methodological components: (1) adjustment for length of stay prior to infection onset and consideration of time-dependent bias, (2) adjustment for comorbidities or severity of disease, and (3) adjustment for inappropriate antibiotic therapy.

Results

Of 1094 identified studies, we identified 12 peer-reviewed articles and two reports that quantified the economic burden of clinically important resistant infections. Two studies used multi-state modelling to account for the timing of infection minimising the risk of time dependent bias and these were considered to generate the best available cost estimates. Studies report an additional CHF 9473 per extended-spectrum beta-lactamases -resistant Enterobacteriaceae bloodstream infections (BSI); additional €3200 per third-generation cephalosporin resistant Enterobacteriaceae BSI; and additional €1600 per methicillin-resistant S. aureus (MRSA) BSI. The remaining studies either partially adjusted or did not consider the timing of infection in their analysis.

Conclusions

Implementation of AMR policy and decision-making should be guided only by reliable, unbiased estimates of effect size. Generating these estimates requires a thorough understanding of important biases and their impact on measured outcomes. This will ensure that researchers, clinicians, and other key decision makers concerned with increasing public health threat of AMR are accurately guided by the best available evidence.

Electronic supplementary material

The online version of this article (10.1186/s13756-019-0472-z) contains supplementary material, which is available to authorized users.

Estimating excess length of stay due to healthcare-associated infections: a systematic review and meta-analysis of statistical methodology

BACKGROUND

Healthcare-associated infection (HCAI) affects millions of patients worldwide. HCAI is associated with increased healthcare costs, owing primarily to increased hospital length of stay (LOS) but calculating these costs is complicated due to time-dependent bias. Accurate estimation of excess LOS due to HCAI is essential to ensure that we invest in cost-effective infection prevention and control (IPC) measures.

AIM

To identify and review the main statistical methods that have been employed to estimate differential LOS between patients with, and without, HCAI; to highlight and discuss potential biases of all statistical approaches.

METHODS

A systematic review from 1997 to April 2017 was conducted in PubMed, CINAHL, ProQuest and EconLit databases. Studies were quality-assessed using an adapted Newcastle-Ottawa Scale (NOS). Methods were categorized as time-fixed or time-varying, with the former exhibiting time-dependent bias. Two examples of meta-analysis were used to illustrate how estimates of excess LOS differ between different studies.

FINDINGS

Ninety-two studies with estimates on excess LOS were identified. The majority of articles employed time-fixed methods (75%). Studies using time-varying methods are of higher quality according to NOS. Studies using time-fixed methods overestimate additional LOS attributable to HCAI. Undertaking meta-analysis is challenging due to a variety of study designs and reporting styles. Study differences are further magnified by heterogeneous populations, case definitions, causative organisms, and susceptibilities.

CONCLUSION

Methodologies have evolved over the last 20 years but there is still a significant body of evidence reliant upon time-fixed methods. Robust estimates are required to inform investment in cost-effective IPC interventions.

Antimicrobial resistance of pathogens causing nosocomial bloodstream infection in Hubei Province, China, from 2014 to 2016: a multicenter retrospective study

BACKGROUND

Data on the pathogens responsible for nosocomial bloodstream infection (BSI) and their antimicrobial resistance (AMR) in Hubei province are limited. This study was conducted to determine the major pathogens causing BSI and to characterize their AMR.

METHODS

Data from the China Antimicrobial Resistance Surveillance System (CARSS) from 2014 to 2016 were analyzed retrospectively.

RESULTS

Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae were the most common pathogens responsible for nosocomial BSI. Individuals aged 0-5 years and ≥ 40 years old were the major demographics at risk of infection by E. coli, K. pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii and Enterobacter cloacae, while individuals aged 0-5 years were the major demographic at risk of infection by S. aureus, Enterococcus faecalis, E. faecium, Streptococcus pneumoniae and Stenotrophomonas maltophilia. The frequencies of E. coli and K. pneumoniae isolates resistant to cefotaxime were 59.1% and 24.3%, respectively, and the frequencies of resistant isolates to ceftazidime were 42.9% and 27.2%, respectively. From 2014 to 2016, the frequency of extended-spectrum β-lactamase (ESBL)-positive E. coli declined from 29.07 to 24.5%, and the frequency of ESBL-positive K. pneumoniae declined from 18.64 to 12.33%. The frequency of carbapenem-resistant (CR) E. coli was below 0.5%, but 1-10% of K. pneumoniae isolates were CR.

CONCLUSIONS

The emergence of methicillin-resistant S. aureus and the expansion of ESBL and fluoroquinolone resistance among Gram-negative Enterobacteriaceae increased AMR severity. Carbapenemase-producing K. pneumoniae isolates responsible for nosocomial BSI increased year over year and effective infection control measures should be taken to prevent them from spreading.

Extended-spectrum β-lactamase-producing E. coli septicemia among rectal carriers in the ICU

The aim of this study was to identify risk factors for extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E coli) bloodstream infection (BSI) among carriers hospitalized between March 2011 and June 2016 at the ICU of the West China Hospital.The cases were patients with at least 1 episode of ESBL-producing E coli BSI within 1 week after a positive rectal swab. Controls were selected randomly 1:2 among ESBL-producing E coli rectal carriers who did not develop BSI.Among 19,429 ICU patients, 9015 (46.4%) had a positive rectal swab for ESBL-producing E coli. Of them, 42 (0.5%) were diagnosed with ESBL-producing E coli BSI. The in-hospital mortality was higher for the BSI patients compared with controls (19.1% vs. 6.0%, P = .031). In the past 72 hours, patients in case group were more likely to use penicillin (odds ratio [OR] = 12.076; 95% confidence interval [CI]: 1.397-104.251, P = .02), cephalosporin (OR = 6.900; 95% CI: 1.493-31.852, P = .01), and carbapenem (OR = 5.422; 95% CI: 1.228-23.907, P = .03) as compared to patients in control group. Also, when compared to patients in control group, patients in case group were likely to stay for a longer time in ICU before positive rectal swab test (OR = 1.041, 95% CI: 1.009-1.075, P = .01) and have higher maximum body temperature before positive rectal swab (OR = 8.014; 95% CI: 2.408-26.620, P = .001).Bacteremia owing to ESBL-producing E coli was associated with high antimicrobial exposure, hospital stay, and maximum body temperature.

Letter to the editor in response to estimating the burden of antimicrobial resistance: a systematic literature review

The systematic review published by Naylor et al. in April 2018 highlights methodological assumptions and biases that occur in studies investigating the burden of antimicrobial resistance (AMR). They note that, due to both the large diversity of statistical approaches and perspectives chosen, the current evidence base of the burden of AMR is highly variable. Certainly, these conclusions are valid and the authors present a very thorough analysis of the currently published literature with a broad array of drug-bug combinations. But readers are left with limited direction of estimating the current best available estimate of the health and economic burden of AMR. Such estimates are desperately needed to inform clinical management and for priority setting activities and initiative to curbing the global threat of AMR.

Estimating the burden of antimicrobial resistance: a systematic literature review

Background

Accurate estimates of the burden of antimicrobial resistance (AMR) are needed to establish the magnitude of this global threat in terms of both health and cost, and to paramaterise cost-effectiveness evaluations of interventions aiming to tackle the problem. This review aimed to establish the alternative methodologies used in estimating AMR burden in order to appraise the current evidence base.

Methods

MEDLINE, EMBASE, Scopus, EconLit, PubMed and grey literature were searched. English language studies evaluating the impact of AMR (from any microbe) on patient, payer/provider and economic burden published between January 2013 and December 2015 were included. Independent screening of title/abstracts followed by full texts was performed using pre-specified criteria. A study quality score (from zero to one) was derived using Newcastle-Ottawa and Philips checklists. Extracted study data were used to compare study method and resulting burden estimate, according to perspective. Monetary costs were converted into 2013 USD.

Results

Out of 5187 unique retrievals, 214 studies were included. One hundred eighty-seven studies estimated patient health, 75 studies estimated payer/provider and 11 studies estimated economic burden. 64% of included studies were single centre. The majority of studies estimating patient or provider/payer burden used regression techniques. 48% of studies estimating mortality burden found a significant impact from resistance, excess healthcare system costs ranged from non-significance to $1 billion per year, whilst economic burden ranged from $21,832 per case to over $3 trillion in GDP loss. Median quality scores (interquartile range) for patient, payer/provider and economic burden studies were 0.67 (0.56-0.67), 0.56 (0.46-0.67) and 0.53 (0.44-0.60) respectively.

Conclusions

This study highlights what methodological assumptions and biases can occur dependent on chosen outcome and perspective. Currently, there is considerable variability in burden estimates, which can lead in-turn to inaccurate intervention evaluations and poor policy/investment decisions. Future research should utilise the recommendations presented in this review.

Trial registration

This systematic review is registered with PROSPERO (PROSPERO CRD42016037510).

Quantifying Hospital-Acquired Carriage of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae Among Patients in Dutch Hospitals

BACKGROUND

Extended-spectrum β-lactamase–producing Enterobacteriaceae (ESBL-E) are emerging worldwide. Contact precautions are recommended for known ESBL-E carriers to control the spread of ESBL-E within hospitals.

OBJECTIVE

This study quantified the acquisition of ESBL-E rectal carriage among patients in Dutch hospitals, given the application of contact precautions.

METHODS

Data were used from 2 cluster-randomized studies on isolation strategies for ESBL-E: (1) the SoM study, performed in 14 Dutch hospitals from 2011 through 2014 and (2) the R-GNOSIS study, for which data were limited to those collected in a Dutch hospital in 2014. Perianal cultures were obtained, either during ward-based prevalence surveys (SoM), or at admission and twice weekly thereafter (R-GNOSIS). In both studies, contact precautions were applied to all known ESBL-E carriers. Estimates for acquisition of ESBL-E were based on the results of admission and discharge cultures from patients hospitalized for more than 2 days (both studies) and a Markov chain Monte Carlo (MCMC) model, applied to all patients hospitalized (R-GNOSIS).

RESULTS

The absolute risk of acquisition of ESBL-E rectal carriage ranged from 2.4% to 2.9% with an ESBL-E acquisition rate of 2.8 to 3.8 acquisitions per 1,000 patient days. In addition, 28% of acquisitions were attributable to patient-dependent transmission, and the per-admission reproduction number was 0.06.

CONCLUSIONS

The low ESBL-E acquisition rate in this study demonstrates that it is possible to control the nosocomial transmission of ESBL in a low-endemic, non-ICU setting whereEscherichia coliis the most prevalent ESBL-E and standard and contact precautions are applied for known ESBL-E carriers.

TRIAL REGISTRATION

Nederlands Trialregister, NTR2799,http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2799; ISRCTN Registry, ISRCTN57648070,http://www.isrctn.com/ISRCTN57648070

Infect Control Hosp Epidemiol2018;39:32–39

Carbapenem-resistant Enterobacteriaceae in patients admitted to the emergency department: prevalence, risk factors, and acquisition rate

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) have been reported worldwide and are associated with high mortality rates. Intestinal colonization acts as a reservoir and fosters exchange of resistance mechanisms.

AIM

To investigate the prevalence of patients harbouring CRE on hospital admission, risk factors associated, and the acquisition rate within the emergency department (ED).

METHODS

This was a cross-sectional survey with 676 patients consecutively admitted to the ED study during the months of May to July 2016. A questionnaire was performed and rectal swabs were collected from patients on admission, for culture and for multiplex real-time polymerase chain reaction (PCR). If the patient was hospitalized for more than one week in the ED, samples were taken again to determine the acquisition rate of CRE.

FINDINGS

Forty-six patients were colonized; all positive PCR were Klebsiella pneumoniae carbapenemase. The acquisition rate was 18%. Previous exposure to healthcare in the last year, liver disease, and use of antibiotics in the last month were risk factors for colonization. Six patients with no previous exposure to healthcare were CRE-colonized on admission, suggesting transmission of CRE within the community.

CONCLUSION

Screening of high-risk patients on admission to the ED is a strategy to early identify CRE carriage and may contribute to control CRE dissemination.

Multistate Modeling to Analyze Nosocomial Infection Data: An Introduction and Demonstration

OBJECTIVE Multistate and competing risks models have become an established and adequate tool with which to quantify determinants and consequences of nosocomial infections. In this tutorial article, we explain and demonstrate the basics of these models to a broader audience of professionals in health care, infection control, and hospital epidemiology. METHODS Using a publicly available data set from a cohort study of intensive care unit patients, we show how hospital infection data can be displayed and explored graphically and how simple formulas are derived under some simplified assumptions for illustrating the basic ideas behind multistate models. Only a few simply accessible values (event counts and patient days) and a pocket calculator are needed to reveal basic insights into cumulative risk and clinical outcomes of nosocomial infection in terms of mortality and length of stay. RESULTS We show how to use these values to perform basic multistate analyses in own data or to correct biased estimates in published data, as these values are often reported. We also show relationships between multistate-based hazard ratios and odds ratios, which are derived from the popular logistic regression model. CONCLUSIONS No sophisticated statistical software is required to apply a basic multistate model and to avoid typical pitfalls such as time-dependent or competing-risks bias. Infect Control Hosp Epidemiol 2017;38:953-959.

The health and economic burden of bloodstream infections caused by antimicrobial-susceptible and non-susceptible Enterobacteriaceae and Staphylococcus aureus in European hospitals, 2010 and 2011: a multicentre retrospective cohort study

We performed a multicentre retrospective cohort study including 606,649 acute inpatient episodes at 10 European hospitals in 2010 and 2011 to estimate the impact of antimicrobial resistance on hospital mortality, excess length of stay (LOS) and cost. Bloodstream infections (BSI) caused by third-generation cephalosporin-resistant Enterobacteriaceae (3GCRE), meticillin-susceptible (MSSA) and -resistant Staphylococcus aureus (MRSA) increased the daily risk of hospital death (adjusted hazard ratio (HR) = 1.80; 95% confidence interval (CI): 1.34–2.42, HR = 1.81; 95% CI: 1.49–2.20 and HR = 2.42; 95% CI: 1.66–3.51, respectively) and prolonged LOS (9.3 days; 95% CI: 9.2–9.4, 11.5 days; 95% CI: 11.5–11.6 and 13.3 days; 95% CI: 13.2–13.4, respectively). BSI with third-generation cephalosporin-susceptible Enterobacteriaceae (3GCSE) significantly increased LOS (5.9 days; 95% CI: 5.8–5.9) but not hazard of death (1.16; 95% CI: 0.98–1.36). 3GCRE significantly increased the hazard of death (1.63; 95% CI: 1.13–2.35), excess LOS (4.9 days; 95% CI: 1.1–8.7) and cost compared with susceptible strains, whereas meticillin resistance did not. The annual cost of 3GCRE BSI was higher than of MRSA BSI. While BSI with S. aureus had greater impact on mortality, excess LOS and cost than Enterobacteriaceae per infection, the impact of antimicrobial resistance was greater for Enterobacteriaceae.

Increased Costs Associated with Bloodstream Infections Caused by Multidrug-Resistant Gram-Negative Bacteria Are Due Primarily to Patients with Hospital-Acquired Infections

The clinical and economic impacts of bloodstream infections (BSI) due to multidrug-resistant (MDR) Gram-negative bacteria are incompletely understood. From 2009 to 2015, all adult inpatients with Gram-negative BSI at our institution were prospectively enrolled. MDR status was defined as resistance to ≥3 antibiotic classes. Clinical outcomes and inpatient costs associated with the MDR phenotype were identified. Among 891 unique patients with Gram-negative BSI, 292 (33%) were infected with MDR bacteria. In an adjusted analysis, only history of Gram-negative infection was associated with MDR BSI versus non-MDR BSI (odds ratio, 1.60; 95% confidence interval [CI], 1.19 to 2.16; P = 0.002). Patients with MDR BSI had increased BSI recurrence (1.7% [5/292] versus 0.2% [1/599]; P = 0.02) and longer hospital stay (median, 10.0 versus 8.0 days; P = 0.0005). Unadjusted rates of in-hospital mortality did not significantly differ between MDR (26.4% [77/292]) and non-MDR (21.7% [130/599]) groups (P = 0.12). Unadjusted mean costs were 1.62 times higher in MDR than in non-MDR BSI ($59,266 versus $36,452; P = 0.003). This finding persisted after adjustment for patient factors and appropriate empirical antibiotic therapy (means ratio, 1.18; 95% CI, 1.03 to 1.36; P = 0.01). Adjusted analysis of patient subpopulations revealed that the increased cost of MDR BSI occurred primarily among patients with hospital-acquired infections (MDR means ratio, 1.41; 95% CI, 1.10 to 1.82; P = 0.008). MDR Gram-negative BSI are associated with recurrent BSI, longer hospital stays, and increased mean inpatient costs. MDR BSI in patients with hospital-acquired infections primarily account for the increased cost.

Prevalence of O25b-ST131 clone among Escherichia coli strains producing CTX-M-15, CTX-M-14 and CTX-M-92 β-lactamases

BACKGROUND

Dissemination of multidrug-resistant Escherichia coli is closely associated with the worldwide spread of a single clone ST131, which is the main cause of urinary tract and bloodstream infections in patients from nursing homes and immunocompromised patients. The aim of our study was to determine the prevalence of ST131 clone and the replicons involved in the spread of bla_CTX-M genes among O25b-ST131 CTX-M-producing E. coli isolates in Lithuania.

METHODS

The strains included in this study were screened for CTX-M β-lactamase-encoding genes, phylogenetic groups and ST131 clone by PCR. Bacterial conjugation was performed to identify plasmid replicon types responsible for bla_CTX-M genes dissemination.

RESULTS

A total of 158 E. coli clinical non-duplicate ESBL isolates were analyzed. Nearly half (n = 67, 42.4%) of the investigated E. coli isolates belonged to phylogenetic group B2. The isolates producing CTX-M-92 β-lactamases were identified to be the ST131 clone more frequently than the non-ST131 clone (11.5% vs. 3.1%, p = .035). The CTX-M-15 isolates were identified as ST131 isolates less frequently than non-ST131 isolates (50.8% vs. 71.1%; p = .015). The ST131 clone isolates contained type L/M and A/C replicons; a fused FII/FIB replicon was found in four isolates (23.5%). Type HI1 replicon was identified in ST131 E. coli isolates producing CTX-M-15 β-lactamases.

CONCLUSIONS

This study demonstrates the predominance of the ST131 clone among CTX-M β-lactamase-producing E. coli isolates. Dissemination of bla_CTX-M genes in ST131 strains can be linked not only to highly adapted IncF plasmids such as FII/FIB and FII, but also to plasmid replicon types A/C, L/M and HI1.

Intestinal Carriage of Carbapenemase-Producing Organisms: Current Status of Surveillance Methods

Carbapenemases have become a significant mechanism for broad-spectrum β-lactam resistance in Enterobacteriaceae and other Gram-negative bacteria such as Pseudomonas and Acinetobacter spp. Intestinal carriage of carbapenemase-producing organisms (CPOs) is an important source of transmission. Isolation of carriers is one strategy that can be used to limit the spread of these bacteria. In this review, we critically examine the clinical performance, advantages, and disadvantages of methods available for the detection of intestinal carriage of CPOs. Culture-based methods (Centers for Disease Control and Prevention [CDC] protocols, chromogenic media, specialized agars, and double-disk synergy tests) for detecting carriage of CPOs are convenient due to their ready availability and low cost, but their limited sensitivity and long turnaround time may not always be optimal for infection control practices. Contemporary nucleic acid amplification techniques (NAATs) such as real-time PCR, hybridization assays, loop-mediated isothermal amplification (LAMP), or a combined culture and NAAT approach may provide fast results and/or added sensitivity and specificity compared with culture-based methods. Infection control practitioners and clinical microbiologists should be aware of the strengths and limitations of available methods to determine the most suitable approach for their medical facility to fit their infection control needs.

Infections caused by extended-spectrum beta-lactamases producing Enterobacteriaceae: clinical and economic impact in patients hospitalized in 2 teaching hospitals in Dakar, Senegal

BACKGROUND

Infections caused by extended-spectrum beta-lactamases producing Enterobacteriaceae (ESBL-E) are of major concern in clinical practice because of limited therapeutic options effective to treat them. Published studies showed that ESBL-E, widely spread in Europe, United States or Asia; are also frequent in Africa. However, the impact of ESBL-E infections is yet to be adequately determined in Sub-Saharan African countries, particularly in Senegal. The aim of our study was to estimate the incidence rate of ESBL-E infections and to assess their clinical and economic impact in Senegal.

METHODS

Two retrospective cohort studies were conducted in patients hospitalized from April to October 2012. A classic retrospective cohort study comparing patients infected by an Enterobacteriaceae producer of ESBL (ESBL+) and patients infected by an Enterobacteriaceae non-producer of ESBL (ESBL-) was carried out for fatal outcomes. Besides, a retrospective parallel cohort study comparing infected patients by an ESBL+ and ESBL- versus uninfected patients was carried out for the excess LOS analyses. Multivariable regression analysis was performed to identify risk factors for fatal outcomes. A multistate model and a cost-of-illness analysis were used to estimate respectively the excess length of stay (LOS) attributable to ESBL production and costs associated. Cox proportional hazards models were used to assess the independent effect of ESBL+ and ESBL- infections on LOS.

RESULTS

The incidence rate of ESBL-E infections was 3 cases/1000 patient-days (95 % CI: 2.4-3.5 cases/1000 patient-days). Case fatality rate was higher in ESBL+ than in ESBL- infections (47.3 % versus 22.4 %, p = 0.0006). Multivariable analysis indicated that risk factors for fatal outcomes were the production of ESBL (OR = 5.7, 95 % CI: 3.2-29.6, p = 0.015) or being under mechanical ventilation (OR = 5.6, 95 % CI: 2.9-57.5, p = 0.030). Newborns and patients suffering from meningitidis or cancer were patients at-risk for fatal outcomes. ESBL production increased hospital LOS (+4 days) and reduced significantly the hazard of discharge after controlling for confounders (HR = 0.3, 95 % CI:0.2-0.4). The additional cost associated with ESBL-production of €100 is substantial given the lower-middle-income status of Senegal.

CONCLUSION

Our findings show an important clinical and economic impact of ESBL-E infections in Senegal and emphasize the need to implement adequate infection control measures to reduce their incidence rate. An antibiotic stewardship program is also crucial to preserve the effectiveness of our last-resort antibiotic drugs.

Epidemiology and Burden of Bloodstream Infections Caused by Extended-Spectrum Beta-Lactamase Producing Enterobacteriaceae in a Pediatric Hospital in Senegal

Context

Severe bacterial infections are not considered as a leading cause of death in young children in sub-Saharan Africa. The worldwide emergence of extended-spectrum beta-lactamase producing Enterobacteriaceae (ESBL-E) could change the paradigm, especially in neonates who are at high risk of developing healthcare-associated infections.

Objective

To evaluate the epidemiology and the burden of ESBL-E bloodstream infections (BSI).

Methods

A case-case-control study was conducted in patients admitted in a pediatric hospital during two consecutive years. Cases were patients with Enterobacteriaceae BSI and included ESBL-positive (cases 1) and ESBL-negative BSI (cases 2). Controls were patients with no BSI. Multivariate analysis using a stepwise logistic regression was performed to identify risk factors for ESBL acquisition and for fatal outcomes. A multistate model was used to estimate the excess length of hospital stay (LOS) attributable to ESBL production while accounting for time of infection. Cox proportional hazards models were performed to assess the independent effect of ESBL-positive and negative BSI on LOS.

Results

The incidence rate of ESBL-E BSI was of 1.52 cases/1000 patient-days (95% CI: 1.2–5.6 cases per 1000 patient-days). Multivariate analysis showed that independent risk factors for ESBL-BSI acquisition were related to underlying comorbidities (sickle cell disease OR = 3.1 (95%CI: 2.3–4.9), malnutrition OR = 2.0 (95%CI: 1.7–2.6)) and invasive procedures (mechanical ventilation OR = 3.5 (95%CI: 2.7–5.3)). Neonates were also identified to be at risk for ESBL-E BSI. Inadequate initial antibiotic therapy was more frequent in ESBL-positive BSI than ESBL-negative BSI (94.2% versus 5.7%, p<0.0001). ESBL-positive BSI was associated with higher case-fatality rate than ESBL-negative BSI (54.8% versus 15.4%, p<0.001). Multistate modelling indicated an excess LOS attributable to ESBL production of 4.3 days. The adjusted end-of-LOS hazard ratio for ESBL-positive BSI was 0.07 (95%CI, 0.04–0.12).

Conclusion

Control of ESBL-E spread is an emergency in pediatric populations and could be achieved with simple cost-effective measures such as hand hygiene, proper management of excreta and better stewardship of antibiotic use, especially for empirical therapy.

Nosocomial bloodstream infections caused by Escherichia coli and Klebsiella pneumoniae resistant to third-generation cephalosporins, Finland, 1999-2013: Trends, patient characteristics and mortality

BACKGROUND

Few systematically collected multi-centre surveillance data on nosocomial bloodstream infections (BSI) caused by extended-spectrum β-lactamase (ESBL) producing Escherichia coli or Klebsiella pneumoniae have been published.

AIM

To evaluate trends, patient characteristics and mortality of such infections, nosocomial BSI data reported by the 4-17 hospitals participating in the prospective laboratory-based surveillance during 1999-2013 were analysed.

METHODS

Data were collected by local infection control nurses, patient-days were obtained from the hospital's administrative database, and dates of deaths from the population registry. Resistance to third-generation cephalosporins was further examined in the national reference laboratory.

FINDINGS

A total of 16 028 nosocomial BSIs were identified; 2217 (14%) were caused by E. coli and 661 (4%) by K. pneumoniae; 207 (7%) were non-susceptible to third-generation cephalosporins, with an increasing trend from 0% in 1999 to 17% in 2013. Patient characteristics did not differ significantly between BSIs caused by third-generation susceptible and resistant E. coli and K. pneumonia, but the case fatality tended to be higher. Most (88%) of the isolates reported as non-susceptible to third-generation cephalosporins had ESBL phenotype, CTX-M (79%) being the most common enzyme.

CONCLUSION

A sharp increase in nosocomial BSIs caused by ESBL producing bacteria was observed. Identification of patients for screening pose a challenge, emphasising the role of infection control guidelines and antibiotic policy in prevention.

Ongoing increasing temporal and geographical trends of the incidence of extended-spectrum beta-lactamase-producing Enterobacteriaceae infections in France, 2009 to 2013

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) are a major focus of multidrug-resistant organisms (MRO) surveillance programmes in France. To describe the temporal and geographical trends of these pathogens, we conducted an epidemiological study based on data extracted from the nationwide MRO surveillance network from 2009 to 2013. During this time, the incidence of ESBL-E infections in French hospitals increased by 73%, from 0.35 to 0.60 per 1,000 patient days (PD) (p < 0.001) and ESBL-E bacteraemia by 77%, from 0.03 to 0.05 per 1,000 PD (p < 0.001). The incidence of ESBL-E infections was higher in intensive-care units (1.62 to 2.44 per 1,000 PD (p < 0.001)) than in recovery and long-term care facilities (0.20 to 0.31 per 1,000 PD (p < 0.001)). Escherichia coli was the most frequent extended-spectrum beta-lactamase-producing (ESBL) pathogen, representing 59% (26,238/44,425) of all ESBL isolates, followed by Klebsiella pneumoniae (20%; 8,856/44,425) in 2013. The most frequent infection was urinary tract infection, for all species. The incidence of ESBL-E varied by region but showed an upward trend overall. Reinforcement of control measures for halting the spread of such MRO is crucial.

Improved treatment of multidrug-resistant bacterial infections: utility of clinical studies

In a time of increasing antibacterial resistance and limited availability of new antibiotics, clinical studies are much needed to assess treatment options against multidrug-resistant organisms (MDROs). In this review, we describe the clinical challenge caused by MDROs and present recent evidence on how clinical studies may generate quality data to improve antibiotic treatment of MDRO infections. To this aim, we critically assess the current status, gaps and challenges associated with observational and interventional studies performed to assess MDRO treatment options. We address why observational studies are useful, which treatment options for MDRO have been explored by observational studies and how to improve quality and usefulness of observational studies. Furthermore, the utility of clinical pharmacokinetic/pharmacodynamic studies for improving MDRO treatment is described. Finally, we discuss interventional study designs, end points and margins, as well as ethical, logistic and statistical challenges, and current regulatory changes proposed to foster the development of new antibiotics.

Extended-spectrum β-lactamase-producing Enterobacteriaceae in hospital food: a risk assessment

OBJECTIVE

Determine the prevalence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-PE) contamination of food and colonization of food handlers in a hospital kitchen and compare retrieved ESBL-PE strains with patient isolates.

DESIGN

Cross-sectional study.

SETTING

A 2,200-bed tertiary care university hospital in Switzerland.

PARTICIPANTS

Food handlers.

METHODS

Raw and prepared food samples were obtained from the hospital kitchen, with a comparator group from local supermarkets. Fecal samples collected from food handlers and selectively pre-enriched homogenized food samples were inoculated onto selective chromogenic media. Phenotypic confirmation of ESBL production was performed using the double disk method. Representative ESBL-PE were characterized using polymerase chain reaction (PCR) and sequencing for blaCTX-M, blaSHV, and blaTEM genes, and Escherichia coli strains were typed using phylotyping, repetitive element palindromic PCR, and multilocus sequence typing. Meat samples were screened for antibiotic residues using liquid chromatography time-of-flight mass spectrometry.

RESULTS

Sixty (92%) of the raw chicken samples were ESBL-PE positive, including 30 (86%) of the hospital samples and all supermarket samples. No egg, beef, rabbit, or cooked chicken samples were ESBL-PE positive. No antibiotic residues were detected. Six (6.5%) of 93 food handlers were ESBL-PE carriers. ESBL-PE strains from chicken meat more commonly possessed blaCTX-M-1 and blaCTX-M-2, whereas blaCTX-M-14 and blaCTX-M-15 were predominant among strains of human origin. There was partial overlap in the sequence type of E. coli strains of chicken and human origin. No E. coli ST131 strains or blaCTX-M-15 genes were isolated from meat.

CONCLUSIONS

Although there is significant ESBL-PE contamination of delivered chicken meat, current preventive strategies minimize risks to food handlers, hospital staff, and patients.

Bloodstream infection due to extended-spectrum beta-lactamase (ESBL)-positive K. pneumoniae and E. coli: an analysis of the disease burden in a large cohort

PURPOSE

The burden of extended-spectrum beta-lactamase (ESBL)-positive Enterobacteriaceae (ESBL-E) is growing worldwide. We aimed to determine the financial disease burden attributable to ESBL-positive species in cases of bloodstream infection (BSI) due to K. pneumoniae and E. coli.

METHODS

We conducted a cohort study on patients with BSI due to K. pneumoniae or E. coli between 2008 and 2011 in our institution. Data were collected on true hospital costs, length of stay (LOS), basic demographic parameters, underlying diseases as Charlson comorbidity index (CCI) and ESBL positivity of the pathogens. Multivariable regression analysis on hospital costs and length of stay was performed.

RESULTS

Overall we found 1,851 consecutive cases of ESBL-E BSI, 352 (19.0%) cases of K. pneumoniae BSI and 1,499 (81.0%) cases of E. coli BSI. Sixty-six of E. coli BSI (18.8%) and 178 of K. pneumoniae BSI (11.9%) cases were due to ESBL-positive isolates, respectively (p = 0.001). 830 (44.8%) cases were hospital-onset, 215 (61.1%) of the K. pneumoniae and 615 (41.0%) of the E. coli cases (p < 0.001). In-hospital mortality was overall 19.8, 25.0% in K. pneumoniae cases and 18.5% in E. coli cases (p = 0.006). Increased hospital costs and length of stay were significantly associated to BSI with ESBL-positive K. pneumoniae.

CONCLUSION

In contrast to BSI due to ESBL-positive E. coli, cases of ESBL-positive K. pneumoniae BSI were associated with significantly increased costs and length of stay. Infection prevention measures should differentiate between both pathogens.

High burden of extended-spectrum β-lactamase-positive Escherichia coli in geriatric patients

Few studies have described how an expanding elderly population influences the burden of antimicrobial resistance in micro-organisms. This study aimed to investigate trends in age-stratified extended-spectrum β-lactamase (ESBL)-positive Escherichia coli metrics in relation to an ageing population. The antimicrobial resistance database of E. coli from a healthcare region in Hong Kong from 2003 to 2012 was retrospectively reviewed. Future trends in age-stratified ESBL metrics were predicted up to 2022. Susceptibility results of clinical E. coli isolates from patients aged 0–74 years (n = 17 853) and aged ≥75 years (n = 17 047) were analysed. For the period 2003–2012, 23.7 % of the hospital admissions were of patients aged ≥75 years. However, approximately half of the annual ESBL-positive E. coli isolates were recovered from patients aged ≥75 years, being 55.0 % (233/424) in 2003 and 56.0 % (639/1142) in 2012. During this period of time, the annual prevalence and cumulative incidence of ESBL-positive E. coli in patients aged ≥75 years were significantly higher than in patients aged 0–74 years. From 2012–2022, it is predicted that ESBL-positive E. coli prevalence among patients aged 0–74 years and ≥75 years would increase from 25.4 % to 50.2 % and from 30.8 % to 70.0 %, respectively. In 2022, the predicted ESBL-positive E. coli cumulative incidence would be 63.7 per 10 000 admissions and 178.7 per 10 000 admissions among patients aged 0–74 years and ≥75 years, respectively. In conclusion, a rapidly expanding elderly population would substantially add to the burden of ESBL.

Mortality and molecular epidemiology associated with extended-spectrum β-lactamase production in Escherichia coli from bloodstream infection

Background

The rate of infections due to extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is growing worldwide. These infections are suspected to be related to increased mortality. We aimed to estimate the difference in mortality due to bloodstream infections (BSIs) with ESBL-positive and ESBL-negative E. coli isolates and to determine the molecular epidemiology of our ESBL-positive isolates.

Materials and methods

We performed a cohort study on consecutive patients with E. coli BSI between 2008 and 2010 at the Charité University Hospital. Collected data were ESBL production, basic demographic parameters, and underlying diseases by the Charlson comorbidity index (CCI). The presence of ESBL genes was analyzed by polymerase chain reaction (PCR) and sequencing. Phylogenetic groups of ESBL-positive E. coli were determined by PCR. Risk factors for mortality were analyzed by multivariable regression analysis.

Results

We identified 115 patients with BSI due to E. coli with ESBL phenotype and 983 due to ESBL-negative E. coli. Fifty-eight percent (n=67) of the ESBL-positive BSIs were hospital-acquired. Among the 99 isolates that were available for PCR screening and sequencing, we found mainly 87 CTX-M producers, with CTX-M-15 (n=55) and CTX-M-1 (n=21) as the most common types. Parameters significantly associated with mortality were age, CCI, and length of stay before and after onset of BSI.

Conclusion

The most common ESBL genotypes in clinical isolates from E. coli BSIs were CTX-M-15 (58%) and CTX-M-1 (22%). ESBL production in clinical E. coli BSI isolates was not related to increased mortality. However, the common occurrence of hospital-acquired BSI due to ESBL-positive E. coli indicates future challenges for hospitals.

Costs and length of stay associated with extended-spectrum β-lactamase production in cases of Escherichia coli bloodstream infection

The prevalence of infections with extended-spectrum β-lactamase (ESBL)-producing bacteria is increasing worldwide. The economic burden of this development has not yet been sufficiently studied. Therefore, this study on hospital costs and length of stay (LoS) associated with cases of bloodstream infection (BSI) due to ESBL-producing Escherichia coli was performed. A matched case-control study of patients with E. coli BSI between 2008 and 2010 in Charité University Hospital (Berlin, Germany) was performed. Cases were patients with ESBL-producing E. coli BSI and controls were patients with ESBL-negative E. coli BSI. Cases and controls were matched in a 1:1 ratio by age ±5 years, sex, underlying co-morbidities, LoS before BSI onset, and discharge year. In total, 1098 consecutive patients with E. coli BSI were identified, comprising 115 (10.5%) ESBL-positive and 983 (89.5%) ESBL-negative. Of the 115 ESBL-positive infections 67 (58.3%) were hospital-acquired in contrast to 382/983 (38.9%) of the ESBL-negative infections (P<0.001). After matching for confounders, there were no significant differences in costs, LoS or mortality between ESBL-positive and ESBL-negative E. coli BSIs. In conclusion, patients with BSI due to ESBL-producing E. coli were neither more costly nor stayed longer in the hospital than patients with BSI due to ESBL-negative E. coli.

Risk factors for hospital-acquired bloodstream infections caused by extended-spectrum β-lactamase Klebsiella pneumoniae among cancer patients

BACKGROUND

Incidence of infection due to extended-spectrum β-lactamase producing Klebsiella pneumoniae (ESBL-KP) has increased rapidly in recent years. However, its prevalence in cancer patients is seldom reported.

AIMS

This study was designed to identify the risk factors for bloodstream infections (BSIs) with ESBL-KP, and to understand its susceptibility among cancer patients on antibiotics.

METHODS

We conducted a retrospective study with a total of 118 cancer patients between 2009 and 2011 with BSIs, among which 88 were infected with non-ESBL-KP and 30 with ESBL-KP. Patterns of susceptibility, clinical characteristics and mortality were investigated. Multivariate logistic regression model was used to unveil independent risk factors.

RESULTS

On multivariate analysis, length of stay (LOS) (p = 0.025), and prior exposure to cephalosporins (p = 0.006), fluoroquinolones (p = 0.011), macrolides (p = 0.007) and aminoglycosides (p = 0.008) were independent risk factors for BSIs of ESBL-KP. For mortality, there was no significant difference between ESBL-KP and non-ESBL-KP groups (p = 0.431). Moreover, compared with non-ESBL-KP, ESBL-KP displayed reduced sensitivity to aminoglycosides (p < 0.001, except amikacin), fluoroquinolones (p < 0.001), piperacillin-tazobactam (p = 0.005) and trimethoprim-sulfamethoxazole (p < 0.001), respectively.

CONCLUSIONS

ESBL-KP exhibited less susceptibility to various non-β-lactamase antibiotics, and infections due to these organisms were related to LOS and preexisting use of antibiotics. Thus, judicious use of all antibiotics should be underscored to reduce the infections caused by ESBL-KP.

Carriage of extended-spectrum beta-lactamase-producing enterobacteriacae among internal medicine patients in Switzerland

Background

The incidence of extended-spectrum beta-lactamase producing-enterobacteriacae (ESBL-E) infection is rising worldwide. We aimed to determine the prevalence and nosocomial acquisition rate of ESBL-E as well as the risk factors for ESBL-E carriage and acquisition amongst patients consecutively admitted to 13 internal medicine units at our hospital who were not previously known to be ESBL-E carriers.

Findings

We screened all patients admitted or transferred to internal medicine units for ESBL-E on admission and discharge using rectal swabs. Of 1072 patients screened, 51 (4.8%) were carriers of an ESBL-E at admission. Of 473 patients who underwent admission and discharge screening, 21 (4.4%) acquired an ESBL-E. On multivariate analysis, diabetes mellitus without end-organ complications (OR 2.87 [1.09-7.08]), connective tissue disease (OR 7.22 [1.17-44.59]), and liver failure (OR 8.39 [1.55-45.45]) were independent risk factors for carriage of an ESBL-E upon admission to hospital (area under the ROC curve, 0.68). Receipt of a first- or second-generation cephalosporin (OR 9.25 [2.22-37.82]), intra-hospital transfer (OR 6.68 [1.71-26.06]), and a hospital stay >21 days (OR 25.17 [4.18-151.68]) were associated with acquisition of an ESBL-E during hospitalisation; whilst admission from home was protective (OR 0.16 [0.06-0.39]) on univariate regression. No risk profile with sufficient accuracy to predict previously unknown carriage on admission or acquisition of ESBL-E could be developed using readily available patient information.

Conclusions

ESBL-E carriage is endemic amongst internal medicine patients at our institution. We were unable to develop a clinical risk profile to accurately predict ESBL-E carriage amongst these patients.