In-hospital Medical Costs of Infections Caused by Carbapenem-resistant Klebsiella pneumoniae

Clinical use of tigecycline may contribute to the widespread dissemination of carbapenem-resistant hypervirulent Klebsiella pneumoniae strains

The emergence of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) poses grave threats to human health. These strains increased dramatically in clinical settings in China in the past few years but not in other parts of the world. Four isogenic K. pneumoniae strains, including classical K. pneumoniae, carbapenem-resistant K. pneumoniae (CRKP), hypervirulent K. pneumoniae (hvKP) and CR-hvKP, were created and subjected to phenotypic characterization, competition assays, mouse sepsis model and rat colonization tests to investigate the mechanisms underlying the widespread nature of CR-hvKP in China. Acquisition of virulence plasmid led to reduced fitness and abolishment of colonization in the gastrointestinal tract, which may explain why hvKP is not clinically prevalent after its emergence for a long time. However, tigecycline treatment facilitated the colonization of hvKP and CR-hvKP and reduced the population of Lactobacillus spp. in animal gut microbiome. Feeding with Lactobacillus spp. could significantly reduce the colonization of hvKP and CR-hvKP in the animal gastrointestinal tract. Our data implied that the clinical use of tigecycline to treat carbapenem-resistant K. pneumoniae infections facilitated the high spread of CR-hvKP in clinical settings in China and demonstrated that Lactobacillus spp. was a potential candidate for anticolonization strategy against CR-hvKP.

Monooxygenases and Antibiotic Resistance: A Focus on Carbapenems

Carbapenems are a group of broad-spectrum beta-lactam antibiotics that in many cases are the last effective defense against infections caused by multidrug-resistant bacteria, such as some strains of Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Resistance to carbapenems has emerged and is beginning to spread, becoming an ongoing public-health problem of global dimensions, causing serious outbreaks, and dramatically limiting treatment options. This paper reviews the role of flavin monooxygenases in antibiotic resistance, with a specific focus on carbapenem resistance and the recently discovered mechanism mediated by Baeyer-Villiger monooxygenases. Flavin monooxygenases are enzymes involved in the metabolism and detoxification of compounds, including antibiotics. Understanding their role in antibiotic resistance is crucial. Carbapenems are powerful antibiotics used to treat severe infections caused by multidrug-resistant bacteria. However, the rise of carbapenem-resistant strains poses a significant challenge. This paper explores the mechanisms by which flavin monooxygenases confer resistance to carbapenems, examining molecular pathways and genetic factors. Additionally, this paper highlights the discovery of Baeyer-Villiger monooxygenases' involvement in antibiotic resistance. These enzymes catalyze the insertion of oxygen atoms into specific chemical bonds. Recent studies have revealed their unexpected role in promoting carbapenem resistance. Through a comprehensive analysis of the literature, this paper contributes to the understanding of the interplay between flavin monooxygenases, carbapenem resistance, and Baeyer-Villiger monooxygenases. By exploring these mechanisms, it aims to inform the development of strategies to combat antibiotic resistance, a critical global health concern.

In vitro Activity of Cefepime/Avibactam Against Carbapenem Resistant Klebsiella pneumoniae and Integrative Metabolomics-Proteomics Approach for Resistance Mechanism: A Single-Center Study

Purpose

We aimed to evaluate the in vitro antibacterial effects of combination of cefepime/avibactam against carbapenem-resistant Klebsiella pneumonia (CRKP) and explore the resistance mechanism of FEP/AVI.

Patients and Methods

This study explored the in vitro antibacterial activities of ceftazidime/avibactam (CAZ/AVI) and cefepime/avibactam (FEP/AVI) against 40 and 76 CRKP clinical isolates. Proteomics and metabolomics were employed to investigate the resistance mechanisms of CRKP to FEP/AVI.

Results

FEP/AVI (MIC50/MIC90 0.5/4-64/4 μg/mL, resistance rate 17.1%) showed better antibacterial activity against CRKP than CAZ/AVI (MIC50/MIC90 4/4-128/4 μg/mL, resistance rate 20%) in vitro. Bioinformatics analysis showed that the differentially expressed proteins (DEPs) were enriched in alanine, aspartate and glutamate metabolism, and ribosome. Remarkably, transcriptional and translational activity-related pathways were inhibited in FEP/AVI resistant CRKP. Overlap analysis suggested that H-NS might play an important role in resistance to FEP/AVI in CRKP. The mRNA levels of DEPs-related genes (adhE, gltB, purA, ftsI and hns) showed the same trends as DEPs in FEP/AVI susceptible and resistant strains. FEP/AVI resistant isolates demonstrated stronger biofilm formation capacity than susceptible isolates. Metabolomics results showed that disturbed metabolites were mainly lipids, and adenine was decreased in FEP/AVI resistant CRKP.

Conclusion

These results indicated that H-NS, GltB and SpoT may directly or indirectly promote biofilm formation of CRKP and led to FEP/AVI resistance, but inhibited ribosomal function. Our study provides a mechanistic insight into the acquisition of resistance to FEP/AVI in Klebsiella pneumoniae.

Clinical characteristics of carbapenem-resistant Klebsiella pneumoniae infection/colonisation in the intensive care unit: a 9-year retrospective study

OBJECTIVES

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection/colonisation has been reported in hospitals. The clinical characteristics of CRKP infection/colonisation in the intensive care unit (ICU) have received little attention. This study aims to investigate the epidemiology and extent of K. pneumoniae (KP) resistance to carbapenems, the sources of CRKP patients and CRKP isolates, and the risk factors for CRKP infection/colonisation.

DESIGN

Retrospective single-centre study.

DATA SOURCE

Clinical data were obtained from electronic medical records.

PARTICIPANTS

Patients isolated with KP in the ICU from January 2012 to December 2020.

MAIN OUTCOME MEASURES

The prevalence and changing trend of CRKP were determined. The extent of KP isolates resistance to carbapenems, the specimen types of KP isolates, and the sources of CRKP patients and CRKP isolates were all examined. The risk factors for CRKP infection/colonisation were also assessed.

RESULTS

The rate of CRKP in KP isolates raised from 11.11% in 2012 to 48.92% in 2020. CRKP isolates were detected in one site in 266 patients (70.56%). The percentage of CRKP isolates not susceptible to imipenem increased from 42.86% in 2012 to 98.53% in 2020. The percentage of CRKP patients from general wards in our hospital and other hospitals gradually converged in 2020 (47.06% vs 52.94%). CRKP isolates were mainly acquired in our ICU (59.68%). Younger age (p=0.018), previous admission (p=0.018), previous ICU stay (p=0.008), prior use of surgical drainage (p=0.012) and gastric tube (p=0.001), and use of carbapenems (p=0.000), tigecycline (p=0.005), β-lactams/β-lactamase inhibitors (p=0.000), fluoroquinolones (p=0.033), and antifungal drugs (p=0.011) within the prior 3 months were independent risk factors for CRKP infection/colonisation.

CONCLUSIONS

Overall, the rate of KP isolates resistance to carbapenems increased, and the severity of this resistance significantly increased. Intensive and local infection/colonisation control measures are necessary for ICU patients, especially those with risk factors for CRKP infection/colonisation.

The economic burden of antibiotic resistance: A systematic review and meta-analysis

INTRODUCTION

Antibiotic resistance (ABR) has substantial global public health concerns. This systematic review aimed to synthesise recent evidence estimating the economic burden of ABR, characterised by study perspectives, healthcare settings, study design, and income of the countries.

METHODS

This systematic review included peer-reviewed articles from PubMed, Medline, and Scopus databases, and grey literature on the topic of the economic burden of ABR, published between January 2016 and December 2021. The study was reported in line with 'Preferred Reporting Items for Systematic Review and Meta-Analysis' (PRISMA). Two reviewers independently screened papers for inclusion first by title, then abstract, and then the full text. Study quality was assessed using appropriate quality assessment tools. Narrative synthesis and meta-analyses of the included studies were conducted.

RESULTS

A total of 29 studies were included in this review. Out of these studies, 69% (20/29) were conducted in high-income economies and the remainder were conducted in upper-and-middle income economies. Most of the studies were conducted from a healthcare or hospital perspective (89.6%, 26/29) and 44.8% (13/29) studies were conducted in tertiary care settings. The available evidence indicates that the attributable cost of resistant infection ranges from -US$2,371.4 to +US$29,289.1 (adjusted for 2020 price) per patient episode; the mean excess length of stay (LoS) is 7.4 days (95% CI: 3.4-11.4), the odds ratios of mortality for resistant infection is 1.844 (95% CI: 1.187-2.865) and readmission is 1.492 (95% CI: 1.231-1.807).

CONCLUSION

Recent publications show that the burden of ABR is substantial. There is still a lack of studies on the economic burden of ABR from low-income economies, and lower-middle-income economies, from a societal perspective, and in relation to primary care. The findings of this review may be of value to researchers, policymakers, clinicians, and those who are working in the field of ABR and health promotion.

SYSTEMATIC REVIEW REGISTRATION

CRD42020193886.

Proximity to human settlement is directly related to carriage of critically important antimicrobial-resistant Escherichia coli and Klebsiella pneumoniae in Silver Gulls

Human population and activities play an important role in dissemination of antimicrobial resistant bacteria. This study investigated the relationship between carriage rates of critically important antimicrobial-resistant (CIA-R) Escherichia coli and Klebsiella pneumoniae by Silver Gulls and their proximity to human populations. Faecal swabs (n = 229) were collected from Silver Gulls across 10 southern coastline locations in Western Australia (WA) traversing 650 kms. The sampling locations included main town centres and remote areas. Fluoroquinolone and extended-spectrum cephalosporin-resistant E. coli and K. pneumoniae were isolated and tested for antimicrobial sensitivity. Genome sequencing was performed on n = 40 subset out of 98 E. coli and n = 14 subset out of 27 K. pneumoniae isolates to validate phenotypic resistance profiles and determine the molecular characteristics of strains. CIA-R E. coli and K. pneumoniae were detected in 69 (30.1 %) and 20 (8.73 %) of the faecal swabs respectively. Two large urban locations tested positive for CIA-R E. coli (frequency ranging from 34.3 % to 84.3 %), and/or for CIA-R K. pneumoniae (frequency ranging from 12.5 % to 50.0 %). A small number of CIA-R E. coli (3/31, 9.7 %) were identified at a small tourist town, but no CIA-R bacteria were recovered from gulls at remote sites. Commonly detected E. coli sequence types (STs) included ST131 (12.5 %) and ST1193 (10.0 %). Five K. pneumoniae STs were detected which included ST4568, ST6, ST485, ST967 and ST307. Resistance genes including bla_CTX-M-3, bla_CTX-M-15 and bla_CTX-M-27 were identified in both bacterial species. High-level colonisation of CIA-R E. coli and K. pneumoniae in Silver Gulls in and around urban areas compared to remote locations substantiates that anthropogenic activities are strongly associated with acquisition of resistant bacteria by gulls.

Evaluation of ERIC-PCR and MALDI-TOF as typing tools for multidrug resistant Klebsiella pneumoniae clinical isolates from a tertiary care center in India

Background and aim

Multidrug resistant Klebsiella pneumoniae is associated with nosocomial infections in both outbreak and non-outbreak situations. The study intends to evaluate the potential of enterobacterial repetitive intergenic consensus- polymerase chain reaction (ERIC-PCR), a genomic based typing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) proteomic-based typing techniques for clonal relatedness among multidrug resistant Klebsiella pneumoniae isolates.

Methodology

Multidrug resistant clinical isolates of Klebsiella pneumoniae (n = 137) were collected from March 2019 to February 2020. Identification and protein-based phylogenetic analysis were performed by MALDI-TOF MS. Genomic typing was done by ERIC-PCR and analyzed by an online data analysis service (PyElph). Dice method with unweighted pair group method with arithmetic mean (UPGMA) program was used to compare the ERIC profiles. The samples were also evaluated by PCR for the presence of genes encoding carbapenemases, extended spectrum beta lactamases (ESBLs) and mobile colistin resistance-1 (mcr1).

Result and conclusion

The study presents ERIC-PCR as more robust and better discriminatory typing tool in comparison to MALDI-TOF for clonal relatedness in multidrug resistant K. pneumoniae clinical isolates. Isolates were typed into 40 ERIC types, and six groups by MALDI-TOF-MS. PCR-based analysis revealed that all the strains harbored two or more ESBL and carbapenemase genes. None of the isolates revealed the presence of the plasmid mediated mcr-1 gene for colistin resistance.

Application Effect of Transparent Supervision Based on Informatization in Prevention and Control of Carbapenem-Resistant Klebsiella pneumoniae Nosocomial Infection

Objective

To explore the effect of transparent supervision model on the prevention and control of carbapenem-resistant Klebsiella pneumoniae (CRKP) nosocomial infection and the value of the autoregressive integrated moving average (ARIMA) model in predicting the incidence of CRKP infection.

Methods

A total of 46,873 inpatients from Jiawang District People's Hospital of Xuzhou between January 2019 and December 2019 (prior to COVID-19 prevention and control) were selected as the preintervention group and 45,217 inpatients from January 2020 to December 2020 (after the COVID-19 prevention and control) as the postintervention group. We performed transparent supervision on CRKP patients detected by the real-time monitoring system for nosocomial infection. Incidence and detection rate of CRKP, utilization rate of special grade hydrocarbon enzyme alkene antibiotics, hand hygiene compliance rate, qualified rate of ATP tests on surface of environmental objects, and execution rate of CRKP core prevention and control were compared between the two groups.

Results

Transparent supervision of CRKP-infected patients was conducted daily from January to December 2020, which resulted in the following: (a) the infection rate of CRKP decreased in a fluctuating manner, and the actual value of hydrocarbon alkene use rate was basically the same as the predicted value with an overall decreasing trend; (b) after the intervention, hand hygiene compliance rate increased from 53.30% to 70.24% (P < 0.001) and the ATP qualified rate increased from 53.77% to 92.24% (P < 0.001); (c) the fitted value of the ARIMA model was in good agreement with the actual value. The incidence of CRKP infection and the utilization rate of carbene antibiotics were also in good agreement with the predicted value. The average relative errors were 11% and 10.78%.

Conclusions

During the COVID-19 outbreak in 2020, the ARIMA model effectively fit and predicted the CRKP infection rate, thereby providing scientific guidance for the prevention and control of CRKP infection. In addition, the transparent supervision intervention model improved the hand hygiene compliance and environmental hygiene qualification rates of medical staff, effectively reducing CRKP cross-infection in the hospital.

Mechanistic Insights to Combating NDM- and CTX-M-Coproducing Klebsiella pneumoniae by Targeting Cell Wall Synthesis and Outer Membrane Integrity

Metallo-β-lactamase (MBL)-producing Gram-negative bacteria cause infections associated with high rates of morbidity and mortality. Currently, a leading regimen to treat infections caused by MBL-producing bacteria is aztreonam combined with ceftazidime-avibactam. The purpose of the present study was to evaluate and rationally optimize the combination of aztreonam and ceftazidime-avibactam with and without polymyxin B against a clinical Klebsiella pneumoniae isolate producing NDM-1 and CTX-M by use of the hollow fiber infection model (HFIM). A novel de-escalation approach to polymyxin B dosing was also explored, whereby a standard 0-h loading dose was followed by maintenance doses that were 50% of the typical clinical regimen. In the HFIM, the addition of polymyxin B to aztreonam plus ceftazidime-avibactam significantly improved bacterial killing, leading to eradication, including for the novel de-escalation dosing strategy. Serial samples from the growth control and monotherapies were explored in a Galleria mellonella virulence model to assess virulence changes. Weibull regression showed that low-level ceftazidime resistance and treatment with monotherapy resulted in increased G. mellonella mortality (P < 0.05). A neutropenic rabbit pneumonia model demonstrated that aztreonam plus ceftazidime-avibactam with or without polymyxin B resulted in similar bacterial killing, and these combination therapies were statistically significantly better than monotherapies (P < 0.05). However, only the polymyxin B-containing combination therapy produced a statistically significant decrease in lung weights (P < 0.05), indicating a decreased inflammatory process. Altogether, adding polymyxin B to the combination of aztreonam plus ceftazidime-avibactam for NDM- and CTX-M-producing K. pneumoniae improved bacterial killing effects, reduced lung inflammation, suppressed resistance amplification, and limited virulence changes.

Elevated Mortality Risk from CRKp Associated with Comorbidities: Systematic Review and Meta-Analysis

Carbapenem-resistant Klebsiella pneumoniae has become a public health problem with therapeutic limitations and high mortality associated with comorbidities. Methods: This is a systematic review and meta-analysis with a search in PubMed, SciELO, and Lilacs. Ten articles were selected, considering cohort, case-control, and cross-sectional studies. Tests for proportions and relative risk of mortality were performed, considering a 5% threshold for significance. Statistical analyses were performe dusing Rstudio® software, version 4.0.2 of Ross Ihaka and Robert Genleman in Auckland, New Zealand. Results: Klebsiella pneumoniae, associated with chronic kidney disease, was responsible for 26%/258 deaths, chronic lung disease 28%/169, diabetes 31%/185, liver disease 15%/262, and heart disease 51%/262 deaths. Carbapenem-resistant Klebsiella pneumoniae associated with chronic kidney disease was responsible for 49%/83 deaths, with diabetes 29%/73, and with liver disease 33%/73 deaths. The risk of death from carbapenem-resistant Klebsiella pneumoniae was twice as high as the number of deaths associated with carbapenem-sensitive Klebsiella pneumoniae, RR = 2.07 (p < 0.00001). Conclusions: The present study showed an increase in mortality from carbapenem-resistant Klebsiella pneumoniae when associated with comorbidities.

Outcomes and Risk Factors of Bloodstream Infections Caused by Carbapenem-Resistant and Non-Carbapenem-Resistant Klebsiella pneumoniae in China

Purpose

To compare antimicrobial resistance, virulence, clinical characteristics, and risk factors between carbapenem-resistant K. pneumoniae (CRKP) and carbapenem-susceptible K. pneumoniae (CSKP) isolates from patients with bloodstream infections (BSIs) in China.

Patients and Methods

The clinical data of 103 patients with K. pneumoniae BSI from 10 hospitals were retrospectively analyzed. The minimum inhibitory concentrations of 15 antibiotics against the bacteria were determined. A Galleria mellonella infection model was used to evaluate virulence of the isolates. Kaplan-Meier curves were calculated to evaluate the 28-day and in-hospital survival rates of the isolates. The risk factors for CRKP and CSKP infection and respective mortality rate were evaluated by univariate analysis, and independent risk factors were evaluated using the multivariate logistic regression model.

Results

Our results indicated that CRKP isolates were more resistant to most tested antibiotics than CSKP isolates. The G. mellonella infection model was used to demonstrate that CRKP isolates were more virulent than CSKP isolates. We found that in-hospital deaths occurred in 39.3% (22/56) of patients with CRKP BSIs and were significantly higher than those in patients with CSKP infections (19.1%, 9/47). Patients infected with CRKP isolates had poorer outcomes than those infected with the CSKP strains. For in-hospital mortality of CRKP BSIs, the independent risk factors included carbapenem-resistant Enterobacterales bacteremia and length of hospitalization after the onset of BSI.

Conclusion

Our findings confirm that CRKP isolates are more drug-resistant than CSKP isolates and are associated with poorer outcomes. To prevent CRKP infection, strict infection control strategies and active surveillance should be implemented in hospitals.

Coexistence of bla NDM-1 and bla IMP-4 in One Novel Hybrid Plasmid Confers Transferable Carbapenem Resistance in an ST20-K28 Klebsiella pneumoniae

Objectives

We identified a novel hybrid plasmid simultaneously carrying bla_NDM-1 and bla_IMP-4 in an ST20-K28 carbapenem-resistant Klebsiella pneumoniae (CRKP) strain AZS099 and reported its detailed genetic and phenotypic characterization.

Methods

Antimicrobial susceptibility was characterized using broth microdilution method. Complete genome characteristics and plasmid detailed analysis were carried out by PacBio Sequel and Illumina sequencing and further bioinformatics analysis. Conjugation assay, S1-PFGE, Southern blot, plasmid stability, and fitness cost were conducted to the phenotypic characterization of this novel hybrid plasmid.

Results

AZS099 was isolated from a blood specimen obtained from a 3-month baby who presented with biliary tract infection. Susceptibility testing showed that AZS099 was resistant to almost all β-lactams examined, including cephalosporins, combinations of β-lactams and β-lactamase inhibitors, carbapenems, and aztreonam. PacBio and Illumina sequencing together with S1-PFGE and Southern blot showed that bla_NDM-1 and bla_IMP-4 were simultaneously located on a 296 kb IncFIB(K)/IncHI1B/IncX3 plasmid (pAZS099-NDM-IMP), which consists of four main parts that came from four different types of plasmids. The region harboring bla_IMP-4 is located in a class 1 integron designated as In0, which is located in an IS6100-IS26 transposon-like structure with a total length of ~5 kb. The region harboring bla_NDM-1 is located in the Tn125 transposon remnant. Conjugation and transformation assay confirmed that the plasmid pAZS099-NDM-IMP has the potential for horizontal transfer and displayed high stability (retention rate > 95%). Furthermore, growth curve assessment confirmed that the presence of pAZS099-NDM-IMP exhibits no growth pressure on bacteria.

Conclusion

Our research reported a hybrid plasmid coharboring bla_NDM-1 and bla_IMP-4 in an ST20-K28 CRKP strain. The emergence of novel hybrid plasmid could threaten the control of antimicrobial resistance and should be closely supervised.

Prevalence of Carbapenem-Resistant Hypervirulent Klebsiella pneumoniae and Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae in China Determined via Mouse Lethality Tests

Objective

To investigate the epidemiology of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-HvKP) and hypervirulent carbapenem-resistant Klebsiella pneumoniae (Hv-CRKP).

Methods

Totally 436 K. pneumoniae strains were collected from 7 hospitals in mainland China between 2017.01 and 2018.02. Sequence types, serotypes, antimicrobial-resistance and virulence genes were analyzed. Additionally, string test, capsule stain, Periodic Acid Schiff stain, fitness analysis, quantitative real-time PCR and mouse lethality test were also performed. Molecular combinations were used to screen putative bla_KPC(+)-HvKP and Hv-bla_KPC(+)-KP, followed by the confirmation of mouse lethality test.

Results

Diverse detection rates were found for the virulence genes, ranging from c-rmpA (0.0%) to entB (100.0%). According to the molecular criteria, 127, 186, 9 and 26 strains were putatively denoted as HvKP, bla_KPC(+)-KP, bla_KPC(+)-HvKP and Hv-bla_KPC(+)-KP. Mouse lethality test confirmed 2 bla_KPC(+)-HvKP strains (JS184 and TZ20) and no Hv-bla_KPC(+)-KP. JS184 showed K2 serotype, thin capsule, positive exopolysaccharid and string test. TZ20 presented K20 serotype, thin capsule, negative exopolysaccharide and string test. Compared with the positive control NTUH-K2044, equal galF expression and growth curves were confirmed for JS184 and TZ20.

Conclusions

Molecular determination of CR-HvKP and Hv-CRKP brings remarkable bias compared with mouse lethality test. The exact prevalence of CR-HvKP is less than 1.0%, which of Hv-CRKP is much lower.

Analysis of Risk Factors and Mortality of Patients with Carbapenem-Resistant Klebsiella pneumoniae Infection

Background

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection is associated with high mortality and has become a major public problem threatening patients. This study aimed to explore risk factors for death in patients with Klebsiella pneumoniae (KP) and identify risk factors for CRKP infection.

Methods

The study retrospectively analyzed clinical characteristics and microbiological data from patients infected with KP from January 2019 to October 2021 to identify risk factors and mortality, using multivariate logistic regression analysis and Cox regression analysis.

Results

A total of 214 KP inpatients were enrolled in our study. The in-hospital mortality rate was significantly higher in patients infected with CRKP (13/68, 19.12%) than carbapenem-susceptible KP (CSKP) (2/146, 1.37%) and the difference was statistically significant (P= 0.03). Multivariate Cox regression analysis showed CRKP isolation (HR 12.26, 95% CI 2.43-61.68, P = 0.002), lower TP (HR 10.50, 95% CI 1.33-82.76, P = 0.03), antibiotic days of therapy >15 (HR 0.08, 95% CI 0.01-0.56, P= 0.01) and length of stay (LOS) (HR 0.03, 95% CI 0.002-0.61, P= 0.02) were independent risk factors for death from KP. Additionally, intensive care unit (ICU) stay (OR 21.69, 95% CI 4.50-118.76, P< 0.001) and previous carbapenem exposure (OR 5.26, 95% CI 1.38-21.19, P= 0.02) are independent risk factors for CRKP.

Conclusion

Our findings showed that patients infected with CRKP have a higher in-hospital mortality rate. Identifying the independent risk factors for CRKP infection may contribute to the management of CRKP and reduce the mortality of KP patients.

Economic impact of an outbreak of carbapenemase producing-Enterobacteriaceae in a surgical intensive care unit

BACKGROUND

A 15-month outbreak of carbapenemase-producing Enterobacterales (CPE) occurred in the surgical intensive care unit (SICU) of our institution. We aimed to estimate the financial impact of this outbreak from the perspective of the French public health insurance system.

METHODS

The characteristics of the colonised/infected CPE patients and outbreak management according to French national guidelines were prospectively collected. Loss of productivity was assessed in terms of the reduction in total number of admissions (TNA) and discharges and in ICU length of stay (LoS). The additional financial burden associated with this outbreak was estimated by the accounting department of the hospital, including the impact of the extended LoS and restricted admissions.

RESULTS

Sixteen CPE patients (19 stays) were hospitalised in the SICU (10/2016-01/2018). The median ICU LoS for the CPE cases was 17 [8-36] days versus 6.5 and 6.1 days in 2016 and 2017, respectively, for the whole SICU population. The total number of lost bed days during the outbreak was 452. The TNA dropped dramatically in 2017 (decrease of 20.6%). The estimated costs were 768,386 EUR for bed days lost; 297,176 EUR and 63,675 EUR for the extended LoS for the CPE cases and the patients on contact precautions, respectively; 34,045 EUR for staff reinforcements; 85,764 EUR for bacteriological screening tests; and 42,857 EUR for antimicrobial treatment. The total financial burden of the outbreak was 1,291,903 EUR.

CONCLUSION

Management of a CPE outbreak in the SICU is associated with a huge financial burden for the unit and for the institution.

Estimating the economic cost of carbapenem resistant Enterobacterales healthcare associated infections in Singapore acute-care hospitals

Quantifying the costs of hospital associated infections (HAIs) caused by carbapenem-resistant Enterobacterales (CRE) can aid hospital decision makers in infection prevention and control decisions. We estimate the costs of a CRE HAI by infection type and the annual costs of CRE HAIs to acute-care hospitals in Singapore. We used tree diagrams to estimate the costs (in Singapore dollar) of different CRE HAI types from the health service perspective and compared them to the costs of carbapenem-susceptible HAIs. We used two approaches to estimate costs-direct costs of consumables for infection prevention and treatment; and costs associated with lost bed days. Cost of a HAI were extrapolated to annual CRE HAI incidence in Singapore acute-care hospitals to estimate the annual cost to the hospitals. We found that the cost of a CRE HAI based on direct cost and lost bed days are SGD$9,913 (95% CI, SGD$9,431-10,395) and SGD$10,044 (95% CI, SGD$9,789-10,300) respectively. CRE HAIs are markedly higher than the carbapenem-susceptible HAIs for all infection types. In both approaches, CRE pneumonia was the costliest infection. Based on a CRE HAI incidence of 233 per 100,000 inpatient admissions, CRE HAIs costed SGD$12.16M (95% CI, SGD$11.84-12.48M) annually based on direct costs, and SGD$12.33M (95% CI, SGD$12.01-12.64M) annually based on lost bed days. In conclusion, we described the cost of CRE HAIs in Singapore hospitals and identified infections with the highest costs. The findings may be useful in informing future economic evaluations of competing CRE HAI prevention and treatment programmes.

Socioeconomic Burden of Bloodstream Infections Caused by Carbapenem-Resistant Enterobacteriaceae

Background

Although infection with carbapenem-resistant Enterobacteriaceae (CRE) has become an urgent public health threat worldwide, the socioeconomic burden of CRE bloodstream infection (BSI) remains to be clarified.

Methods

This retrospective study included all patients infected with Escherichia coli or Klebsiella pneumoniae who were hospitalized for BSI from 2013 to 2015. Socioeconomic burden, including direct and indirect economic burden, was compared in patients infected with carbapenem-sensitive Enterobacteriaceae (CSE) and CRE following 1:1 propensity score matching (PSM) to control for confounding variables.

Results

Data from 879 patients with Enterobacteriaceae BSI were evaluated, including 152 (17.3%) patients infected with CRE and 727 (82.7%) infected with CSE. PSM yielded 112 pairs of 224 patients. Median hospital length of stay did not differ significantly in the CRE and CSE groups (35 vs 29 days, P = 0.089), but in-hospital 28-day mortality rate was significantly higher in patients infected with CRE than with CSE (45.5% vs 32.1%, P = 0.040). Median direct economic burden was significantly greater in patients with CRE-BSI than with CSE-BSI during hospitalization ($24,940.1 vs 16,864.0, P = 0.017) but not during the period after infection ($10,403.4 vs 8498.0, P = 0.178). Drug expenditure accounted for the largest proportion of costs in both groups. The median disability-adjusted life year (DALY) was higher in CRE-BSI than in CSE-BSI patients, but the difference was not statistically significant (7.9 vs 6.7 years, P = 0.190). Median indirect economic burden did not differ significantly in these two groups ($3848.5 vs 1139.9, P = 0.304), although indirect economic burden increased significantly from 2013 to 2015 in patients with CRE-BSI.

Conclusion

Carbapenem resistance had a major impact on the clinical and socioeconomic burden of patients with Enterobacteriaceae BSI. The higher mortality rate in patients with CRE-BSI was associated with increased direct healthcare burden and indirect socioeconomic loss.

Impact of carbapenem resistance on mortality in patients infected with Enterobacteriaceae: a systematic review and meta-analysis

OBJECTIVES

To provide a comprehensive assessment of the impact of carbapenem resistance on mortality among patients infected with Enterobacteriaceae and to explore the source of heterogeneity across studies.

DESIGN

This systematic review was conducted following the guidelines of Cochrane Guidance and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

DATA SOURCES

We conducted a systematic literature search of the PubMed, Embase, Web of Science and Cochrane Library databases to identify relevant studies published between 1 January 1994 and 30 August 2020.

ELIGIBILITY CRITERIA

We included primary observational studies published in English that reported the mortality outcomes for hospitalised patients with confirmed infections due to carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-susceptible Enterobacteriaceae (CSE). Studies with no comparison group or with a comparison group of patients infected with unconfirmed CSE were excluded.

DATA EXTRACTION AND SYNTHESIS

Data extraction and assessment of risk bias were conducted independently by two reviewers. The pooled relative risk and risk difference were calculated as effect measures with 95% CIs using a random effects model. The heterogeneity across studies was assessed by Q-statistic and I² measures.

RESULTS

Of 10 304 studies initially identified, 50 studies were included in the meta-analyses. The results of the meta-analyses showed that carbapenem resistance has a significant positive effect on the probability of death for patients infected with Enterobacteriaceae for any type of mortality outcome. The results of the stratified analysis and meta-regression suggested that the effect of carbapenem resistance on the risk of death varied by infection type, sample size and year of publication.

CONCLUSIONS

Our results suggested that patients with CRE infection still face a greater risk of death than patients with CSE infection do, and an urgent need to develop new antibiotics and appropriate treatments to reduce the risk of death.

PROSPERO REGISTRATION NUMBER

CRD42020176808.

Aminoglycoside or Polymyxin Monotherapy for Treating Complicated Urinary Tract Infections Caused by Extensively Drug-Resistant Pseudomonas aeruginosa: A Propensity Score-Adjusted and Matched Cohort Study

INTRODUCTION

Extensively drug-resistant (XDR) Pseudomonas aeruginosa (PA) infections are difficult to treat. We aimed to compare aminoglycosides or polymyxin monotherapy versus other antibiotic regimens (carbapenems, aztreonam, ceftazidime, cefepime, ceftolozane-tazobactam, or ceftazidime-avibactam) in complicated urinary tract infections (cUTI) caused by XDR-PA.

METHODS

Study performed at a tertiary-care hospital from 2010 to 2019. All consecutive adult patients with XDR-PA urine cultures and diagnosed with cUTI were retrospectively reviewed. XDR phenotype was defined according to Magiorakos et al. A propensity score was used as a covariate in multivariate analyses and for matching. Primary outcome was early clinical failure and at end of treatment (EOT). Main secondary outcomes were 30- and 90-day mortality, microbiological clearance, and antibiotic-related side effects.

RESULTS

Of the 465 episodes screened, 101 were included, 48% were treated with aminoglycoside or colistin monotherapy. Most XDR-PA were susceptible to colistin (100%) and amikacin (43%). Patients treated with antibiotic regimens other than aminoglycosides or polymyxin monotherapy were more likely to have hematologic malignancy (p < 0.001), higher SOFA score (p = 0.048), and bacteremia (p = 0.003). In multivariate models adjusted by propensity score, aminoglycoside or colistin monotherapy was not associated with worse outcomes. After propensity score matching, 28 episodes in each treatment group were matched. Adjusted ORs (95% CI) for early clinical failure and at EOT with aminoglycosides or polymyxin monotherapy were 0.53 (0.18-1.58) and 1.29 (0.34-4.83), respectively. Aminoglycoside or colistin monotherapy was not associated with higher 30-day (HR 0.93, 95% CI 0.17-5.08) or 90-day mortality (HR 0.68, 95% CI 0.20-2.31), nor with absence of microbiological clearance (OR 0.72, 95% CI 0.33-1.58). No statistically significant differences were found in terms of nephrotoxicity. Clostridioides difficile infection was observed only in the "other antibiotic regimens" group (n = 6, 11.3%).

CONCLUSIONS

Aminoglycosides or polymyxin monotherapy showed good efficacy and safety profile in treating cUTI caused by XDR-PA. These results may be useful for antibiotic stewardship activities.

Epidemiology and infection control of carbapenem resistant Acinetobacter baumannii and Klebsiella pneumoniae at a German university hospital: a retrospective study of 5 years (2015-2019)

Background

Carbapenem resistant (CR) Klebsiella pneumoniae (Kp) and Acinetobacter baumannii (Ab) are emerging multidrug resistant bacteria with very limited treatment options in case of infection. Both are well-known causes of nosocomial infections and outbreaks in healthcare facilities.

Methods

A retrospective study was conducted to investigate the epidemiology of inpatients with CR Kp and CR Ab in a 1500-bed German university hospital from 2015 to 2019. We present our infection control concept including a weekly microbiologic screening for patients who shared the ward with a CR Kp or CR Ab index patient.

Results

Within 5 years, 141 CR Kp and 60 CR Ab cases were hospitalized corresponding to 118 unique patients (74 patients with CR Kp, 39 patients with CR Ab and 5 patients with both CR Ab and CR Kp). The mean incidence was 0.045 (CR Kp) and 0.019 (CR Ab) per 100 inpatient cases, respectively. Nosocomial acquisition occurred in 53 cases (37.6%) of the CR Kp group and in 12 cases (20.0%) of the CR Ab group. Clinical infection occurred in 24 cases (17.0%) of the CR Kp group and in 21 cases (35.0%) of the CR Ab group. 14 cases (9.9%) of the CR Kp group and 29 cases (48.3%) of the CR Ab group had a history of a hospital stay abroad within 12 months prior to admission to our hospital. The weekly microbiologic screening revealed 4 CR Kp cases caused by nosocomial transmission that would have been missed without repetitive screening.

Conclusions

CR Kp and CR Ab cases occurred infrequently. A history of a hospital stay abroad, particularly in the CR Ab group, warrants pre-emptive infection control measures. The weekly microbiologic screening needs further evaluation in terms of its efficiency.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06900-3.

Clinical and economic outcomes attributable to carbapenem-resistant Enterobacterales and delayed appropriate antibiotic therapy in hospitalized patients

OBJECTIVE

To assess the impact of carbapenem resistance and delayed appropriate antibiotic therapy (DAAT) on clinical and economic outcomes among patients with Enterobacterales infection.

METHODS

This retrospective cohort study was conducted in a tertiary-care medical center in Thailand. Hospitalized patients with Enterobacterales infection were included. Infections were classified as carbapenem-resistant Enterobacterales (CRE) or carbapenem-susceptible Enterobacterales (CSE). Multivariate Cox proportional hazard modeling was used to examine the association between CRE with DAAT and 30-day mortality. Generalized linear models were used to examine length of stay (LOS) and in-hospital costs.

RESULTS

In total, 4,509 patients with Enterobacterales infection (age, mean 65.2 ±18.7 years; 43.3% male) were included; 627 patients (13.9%) had CRE infection. Among these CRE patients, 88.2% received DAAT. CRE was associated with additional medication costs of $177 (95% confidence interval [CI], 114–239; P < .001) and additional in-hospital costs of $725 (95% CI, 448–1,002; P < .001). Patients with CRE infections had significantly longer LOS and higher mortality rates than patients with CSE infections: attributable LOS, 7.3 days (95% CI, 5.4–9.1; P < .001) and adjusted hazard ratios (aHR), 1.55 (95% CI, 1.26–1.89; P < .001). CRE with DAAT were associated with significantly longer LOS, higher mortality rates, and in-hospital costs.

CONCLUSION

CRE and DAAT are associated with worse clinical outcomes and higher in-hospital costs among hospitalized patients in a tertiary-care hospital in Thailand.

Acquisition of a Stable and Transferable bla NDM-5-Positive Plasmid With Low Fitness Cost Leading to Ceftazidime/Avibactam Resistance in KPC-2-Producing Klebsiella pneumoniae During Treatment

The emergence and prevalence of carbapenem-resistant Enterobacteriaceae (CRE) have drawn worldwide attention. Ceftazidime/avibactam (CAZ/AVI) gives us a valuable alternative strategy to treat CRE infections. Unfortunately, CAZ/AVI resistance could occur during CAZ/AVI treatment. The CAZ/AVI-resistant Carbapenem-resistant Klebsiella pneumoniae (CR-KP) (KP137060) and earlier CAZ/AVI-susceptible isolate (KP135194) from the same hospitalized patient were collected at Fujian Medical University Union Hospital between October and November 2019. In this study, CAZ/AVI MICs of CAZ/AVI-susceptible and -resistant isolates (KP135194 and KP137060) were 4 mg/L and 128 mg/L, respectively; and the two isolates had the same antibiotic resistance pattern to other carbapenems. Two strains were then submitted for whole-genome sequencing and bioinformatic analysis. ompK36 was not detected in two isolates. No mutation was observed in bla _KPC-2, ompK35 and ompK37 in this study and there was no significant difference of the expression in bla _KPC-2, ompK35 and ompK37 between the two isolates (p>0.05). Two isolates were sequence type 11 and harbored bla _KPC-2, bla _SHV-182 and bla _TEM-1B. Compared with KP135194, KP137060 harbored an additional bla _NDM-5 positive plasmid. bla _NDM-5 gene could be successfully transferred into E. coli J53 at a conjugation frequency of 1.14×10^-4. Plasmid stability testing showed that bla _KPC-2- and bla _NDM-5-harboring plasmids were still stably maintained in the hosts. Growth assay and growth competition experiments showed there was no significant difference in fitness cost between two CR-KP isolates. Our study described the acquisition of a bla _NDM-5-harboring plasmid leading to resistance to ceftazidime/avibactam in KPC-2-producing Klebsiella pneumoniae during treatment. This phenomenon deserves further exploration.

Research on the economic loss of hospital-acquired pneumonia caused by Klebsiella pneumonia base on propensity score matching

BACKGROUND

Hospital-acquired pneumonia (HAP) caused by Klebsiella pneumonia (KP) is a common nosocomial infection (NI). However, the reports on the economic burden of hospital-acquired pneumonia caused by Klebsiella pneumonia (KP-HAP) were scarce. The study aims to study the direct economic loss caused by KP-HAP with the method of propensity score matching (PSM) to provide a basis for the cost accounting of NI and provide references for the formulation of infection control measures.

METHODS

A retrospective investigation was conducted on the hospitalization information of all patients discharged from a tertiary group hospital in Shenzhen, Guangdong province, China, from June 2016 to August 2019. According to the inclusion and exclusion criteria, patients were divided into the HAP group and noninfection group, the extended-spectrum beta-lactamases (ESBLs) positive KP infection group, and the ESBLs-negative KP infection group. After the baselines of each group were balanced with the PSM, length of stay (LOS) and hospital cost of each group were compared.

RESULTS

After the PSM, there were no differences in the baselines of each group. Compared with the noninfection group, the median LOS in the KP-HAP group increased by 15 days (2.14 times), and the median hospital costs increased by 7329 yuan (0.89 times). Compared with the ESBLs-negative KP-HAP group, the median LOS in the ESBLs-positive KP-HAP group increased by 7.5 days (0.39 times), and the median hospital costs increased by 22,424 yuan (1.90 times).

CONCLUSION

KP-HAP prolonged LOS and increased hospital costs, and HAP caused by ESBLs-positive KP had more economic losses than ESBLs-negative, which deserves our attention and should be controlled by practical measures.

A global perspective on the convergence of hypervirulence and carbapenem resistance in Klebsiella pneumoniae

Hypervirulence and carbapenem resistance have emerged as two distinct evolutionary directions for Klebsiella pneumoniae, which pose a great threat in clinical settings. Multiple virulence factors contribute to hypervirulence, and the mechanisms of carbapenem resistance are complicated. However, more and more K. pneumoniae strains have been identified in recent years integrating both phenotypes, resulting in devastating clinical outcomes. Hypervirulent and carbapenem-resistant K. pneumoniae (CR-hvKP) emerged in the early 2010s and thereafter have become increasingly prevalent. CR-hvKP are primarily prevalent in Asia, especially China, but are reported all over the world. Mechanisms for the emergence of CR-hvKP can be summarised by three patterns: (i) carbapenem-resistant K. pneumoniae (CRKP) acquiring a hypervirulent phenotype; (ii) hypervirulent K. pneumoniae (hvKP) acquiring a carbapenem-resistant phenotype; and (iii) K. pneumoniae acquiring both a carbapenem resistance and hypervirulence hybrid plasmid. With their global dissemination, continued surveillance of the emergence of CR-hvKP should be more highly prioritised.

Healthcare resource use in hospitalized patients with carbapenem-resistant Gram-negative infections

OBJECTIVES

Antimicrobial resistance (AMR) is a threat to global public health. Infections with resistant organisms are more challenging to treat, often delay patient recovery and can increase morbidity and mortality. Healthcare costs associated with treating patients with AMR organisms are poorly described. In particular, data for specific organisms, such as those harbouring carbapenem resistance, are lacking.

METHODS

This was a retrospective, matched (1:1), single-centre, cohort study at a Central London hospital, comparing costs and resource use of 442 adult inpatients infected with either carbapenem-sensitive (CSO) or carbapenem-resistant organisms (CRO) over a two-year period. Resource use and micro-costing data were obtained from the hospital Patient, Education and Research Costing System (PERCS), and included both direct and indirect costs.

RESULTS

Overall, the median healthcare-related cost of treating a patient with a CRO was more than double (£49,537 vs £19,299) that of treating a patient with a CSO. There were statistically significant increases in expenditure across 21 of 44 measured parameters including critical care costs, which accounted for the greatest proportion of overall costs in both groups. Infections were predominantly of the respiratory tract (41%) and caused by Pseudomonas aeruginosa (76%).

CONCLUSIONS

Infection with CROs increases healthcare expenditure significantly. Many of the costs, including patient support, portering and catering, have been underappreciated in previous work. We additionally note that patients infected with CROs have longer hospital stays, and increased theatre operating times compared with patients infected with CSOs.

Clinical and Economic Impact of Third-Generation Cephalosporin-Resistant Infection or Colonization Caused by Escherichia coli and Klebsiella pneumoniae: A Multicenter Study in China

Quantifying economic and clinical outcomes for interventions could help to reduce third-generation cephalosporin resistance and Escherichia coli or Klebsiella pneumoniae. We aimed to compare the differences in clinical and economic burden between third-generation cephalosporin-resistant E. coli (3GCREC) and third-generation cephalosporin-susceptible E. coli (3GCSEC) cases, and between third-generation cephalosporin-resistant K. pneumoniae (3GCRKP) and third-generation cephalosporin-susceptible K. pneumoniae (3GCSKP) cases. A retrospective and multicenter study was conducted. We collected data from electronic medical records for patients who had clinical samples positive for E. coli or K. pneumoniae isolates during 2013 and 2015. Propensity score matching (PSM) was conducted to minimize the impact of potential confounding variables, including age, sex, insurance, number of diagnoses, Charlson comorbidity index, admission to intensive care unit, surgery, and comorbidities. We also repeated the PSM including length of stay (LOS) before culture. The main indicators included economic costs, LOS and hospital mortality. The proportions of 3GCREC and 3GCRKP in the sampled hospitals were 44.3% and 32.5%, respectively. In the two PSM methods, 1804 pairs and 1521 pairs were generated, and 1815 pairs and 1617 pairs were obtained, respectively. Compared with susceptible cases, those with 3GCREC and 3GCRKP were associated with significantly increased total hospital cost and excess LOS. Inpatients with 3GCRKP were significantly associated with higher hospital mortality compared with 3GCSKP cases, however, there was no significant difference between 3GCREC and 3GCSEC cases. Cost reduction and outcome improvement could be achieved through a preventative approach in terms of both antimicrobial stewardship and preventing the transmission of organisms.

Time to positivity of Klebsiella pneumoniae in blood culture as prognostic indicator for pediatric bloodstream infections

The aim of this study is to explore the prognostic values and optimal cutoff point of time to positivity (TTP) of blood culture in children with Klebsiella pneumoniae (K. pneumoniae) bloodstream infection. Ninety-four children with K. pneumoniae bloodstream infection hospitalized in Children's Hospital of Chongqing Medical University from April 2014 to January 2019 were enrolled retrospectively. TTP and risk factors were determined and analyzed by receiver operating characteristic (ROC) analysis and logistic regression analysis. The standard cutoff point of TTP was 13 h. Patients in early TTP (≤ 13 h) group had significantly higher in-hospital mortality (37.93% vs 6.15%, P = 0.000), higher incidence of septic shock (44.83% vs 6.15%, P = 0.000), higher proportion of PRISM III scores ≥ 10 (48.28% vs 20.00%, P = 0.005), and higher proportion of hypoalbuminemia on admission (44.83% vs 18.46%, P = 0.008). Multivariate analysis indicated PRISM III scores ≥ 10, early TTP, and hypoalbuminemia on admission were independent risk factors of in-hospital mortality (OR 8.36, 95% CI 1.80-38.92, P = 0.007; OR 5.85, 95% CI 1.33-25.61, P = 0.019; OR 5.73, 95% CI 1.30-25.22, P = 0.021, respectively) and septic shock (OR 14.04, 95% CI 2.63-75.38, P = 0.002; OR 11.26, 95% CI 2.10-60.22, P = 0.005; OR 10.27, 95% CI 2.01-52.35, P = 0.005, respectively).Conclusion: Early TTP (TTP ≤ 13 h), PRISM III scores ≥ 10, and hypoalbuminemia on admission appeared to be associated with worse outcomes for K. pneumoniae bloodstream infection children. What is Known: • Klebsiella pneumoniae bloodstream infection is an important cause of infectious disease morbidity and mortality worldwide in children. • Short duration of time to positivity indicated poor clinical outcomes. What is New: • Time to positivity ≤ 13 h, along with PRISM III scores ≥ 10 and hypoalbuminemia on admission, indicated higher in-hospital mortality and incidence of septic shock in Klebsiella pneumoniae bloodstream infection children. • The cut-off point of TTP in this pediatric study was much longer than that reported in adult patients.

Clinical and Economic Burden of Carbapenem-Resistant Infection or Colonization Caused by Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii: A Multicenter Study in China

Background: Carbapenem resistant Klebsiella pneumoniae (CRKP), Pseudomonas aeruginosa (CRPA), and Acinetobacter baumannii (CRAB) pose significant threats to public health. However, the clinical and economic impacts of CRKP, CRPA, and CRAB remain largely uninvestigated in China. This study aimed to examine the clinical and economic burden of CRKP, CRPA, and CRAB compared with carbapenem susceptible cases in China. Method: We conducted a retrospective and multicenter study among inpatients hospitalized at four tertiary hospitals between 2013 and 2015 who had K. pneumoniae, P. aeruginosa, and A. baumannii positive clinical samples. Propensity score matching (PSM) was used to balance the impact of potential confounding variables, including age, sex, insurance, number of diagnosis, comorbidities (disease diagnosis, and Charlson comorbidity index), admission to intensive care unit, and surgeries. The main indicators included economic costs, length of stay (LOS), and mortality rate. Results: We included 12,022 inpatients infected or colonized with K. pneumoniae, P. aeruginosa, and A. baumannii between 2013 and 2015, including 831 with CRKP and 4328 with carbapenem susceptible K. pneumoniae (CSKP), 1244 with CRPA and 2674 with carbapenem susceptible P. aeruginosa (CSPA), 1665 with CRAB and 1280 with carbapenem susceptible A. baumannii (CSAB). After PSM, 822 pairs, 1155 pairs, and 682 pairs, respectively were generated. Compared with carbapenem-susceptible cases, those with CRKP, CRPA, and CRAB were associated with statistically significantly increased total hospital cost ($14,252, p < 0.0001; $4605, p < 0.0001; $7277, p < 0.0001) and excess LOS (13.2 days, p < 0.0001; 5.4 days, p = 0.0003; 15.8 days, p = 0.0004). In addition, there were statistically significantly differences in hospital mortality rate between CRKP and CSKP, and CRAB and CSAB group (2.94%, p = 0.024; 4.03%, p = 0.03); however, the difference between CRPA and CSPA group was marginal significant (2.03%, p = 0.052). Conclusion: It highlights the clinical and economic impact of CRKP, CRPA, and CRAB to justify more resources for implementing antibiotic stewardship practices to improve clinical outcomes and to reduce economic costs.

Clinical and economic impact of methicillin-resistant Staphylococcus aureus: a multicentre study in China

Methicillin-resistant Staphylococcus aureus (MRSA) has become a serious threat to global health. In China, the proportion of S. aureus isolates that were MRSA was 44.6% in 2014. The clinical and economic impact of MRSA in China remains largely uninvestigated. This study aims to compare the differences in hospital costs, length of hospital stay, and hospital mortality rate between MRSA and methicillin-susceptible S. aureus (MSSA) colonization or infection and between MRSA cases and those without an S. aureus infection. A retrospective and multicentre study was conducted in four tertiary hospitals in China between 2013 and 2015. Inpatient characteristics and hospital costs were collected from electronic medical records. We conducted propensity score matching (PSM) to eliminate selection bias by balancing the potential confounding variables between the two groups. The main indicators included hospital costs, length of hospital stay, and hospital mortality rate. A total of 1,335 inpatients with MRSA, 1,397 with MSSA, and 33,606 without an S. aureus infection were included. PSM obtained 954 and 1,313 pairs between the MRSA and MSSA groups and between the MRSA and S. aureus-free groups, respectively. After PSM, MRSA colonization or infection is associated with an increased total hospital cost ranging from $3,220 to $9,606, an excess length of hospital stay of 6 days–14 days, and an attributable hospital mortality rate of 0–3.58%. Between the MRSA and MSSA groups, MRSA colonization or infection was significantly associated with a higher total hospital cost and longer length of hospital stay among survivors but not among non-survivors; however, there were no differences in the hospital mortality rate between these two groups. Between the MRSA and the S. aureus-free groups, MRSA colonization or infection was significantly associated with an increased total hospital cost, a prolonged length of hospital stay and a higher hospital mortality rate among both survivors and non-survivors. It is critical to quantify the clinical and economic impact of MRSA to justify resource allocation for the development of strategies to improve clinical outcomes and to reduce the economic burden.

Clinical and economic burden of community-onset multidrug-resistant infections requiring hospitalization

OBJECTIVES

To analyze the clinical and economic burden of community-acquired (CA) or community-onset healthcare-associated (COHCA) multidrug-resistant (MDR) infections requiring hospitalization.

METHODS

Case-control study. Adults admitted with CA or COHCA MDR infections were considered cases, while those admitted in the same period with non-MDR infections were controls. The matching criteria were source of infection and/or microorganism. Primary outcome was 30-day clinical failure. Secondary outcomes were 90-day and 1-year mortality, hospitalization costs and resource consumption.

RESULTS

194 patients (97 cases and 97 controls) were included. Multivariate analysis identified age (odds ratio [OR], 1.07, 95% confidence interval [CI], 1.01-1.14) and SOFA score (OR, 1.45, CI95%, 1.15-1.84) as independent predictors of 30-day clinical failure. Age (hazard ratio [HR] 1.09, 95%CI, 1.03-1.16) was the only factor associated with 90-day mortality, whereas age (HR 1.06, 95%CI, 1.03-1.09) and Charlson Index (HR 1.2, 95%CI, 1.07-1.34) were associated with 1-year mortality. MDR group showed longer hospitalization (p<0.001) and MDR hospitalization costs almost doubled those in the non-MDR group. MDR infections were associated with higher antimicrobial costs.

CONCLUSIONS

Worse economic outcomes were identified with community-onset MDR infections. MDR was associated with worse clinical outcomes but mainly due to higher comorbidity of patients in MDR group, rather than multidrug resistance.

Synergetic Effects of Combined Treatment of Colistin With Meropenem or Amikacin on Carbapenem-Resistant Klebsiella pneumoniae in vitro

The purpose of this study was to investigate the synergistic and bactericidal effects of combinations of colistin with meropenem or amikacin in vitro and provide laboratory data needed for development of therapeutic strategies for the treatment of carbapenem-resistant Klebsiella pneumoniae (CRKP) infection. We found that minimum inhibitory concentration (MIC) of colistin, meropenem and amikacin were 2~32, 4~256, and 1~16384 μg/ml, respectively. The minimum bactericidal concentration of the antibiotics was either 1× or 2×MIC. Treatments of 6 CRKP isolates at 1 μg/ml colistin completely killed 2 of them and suppressed 4 others growth. 4 CRKP isolates at 16 μg/ml meropenem or amikacin completely killed and suppressed 2 others growth. 2 CRKP isolates showed synergic effects in all colistin combination and 3 CRKP isolates showed synergic effects in part of colistin combination. Our data suggest that colistin in combination with either meropenem or amikacin could be a valid therapeutic option against colistin-resistant CRKP isolates. Moreover, the combination of colistin-amikacin is less expensive to treat CRKP infections in Eastern Heilongjiang Province.

Measuring the in-hospital costs of Pseudomonas aeruginosa pneumonia: methodology and results from a German teaching hospital

Background

Pseudomonas aeruginosa-related pneumonia is an ongoing healthcare challenge. Estimating its financial burden is complicated by the time-dependent nature of the disease.

Methods

Two hundred thirty-six cases of Pseudomonas aeruginosa-related pneumonia were recorded at a 2000 bed German teaching hospital between 2011 and 2014. Thirty-five cases (15%) were multidrug-resistant (MDR) Pseudomonas aeruginosa. Hospital- and community-acquired cases were distinguished by main diagnoses and exposure time. The impact of Pseudomonas aeruginosa-related pneumonia on the three endpoints cost, reimbursement, and length of stay was analyzed, taking into account (1) the time-dependent nature of exposure, (2) clustering of costs within diagnostic groups, and (3) additional confounders.

Results

Pseudomonas aeruginosa pneumonia is associated with substantial additional costs that are not fully reimbursed. Costs are highest for hospital-acquired cases (€19,000 increase over uninfected controls). However, community-acquired cases are also associated with a substantial burden (€8400 when Pseudomonas aeruginosa pneumonia is the main reason for hospitalization, and €6700 when not). Sensitivity analyses for hospital-acquired cases showed that ignoring or incorrectly adjusting for time-dependency substantially biases results. Furthermore, multidrug-resistance was rare and only showed a measurable impact on the cost of community-acquired cases.

Conclusions

Pseudomonas aeruginosa pneumonia creates a substantial financial burden for hospitals. This is particularly the case for nosocomial infections. Infection control interventions could yield significant cost reductions. However, to evaluate the potential effectiveness of different interventions, the time-dependent aspects of incremental costs must be considered to avoid introduction of bias.

Characterization and genome sequencing of a novel T7-like lytic phage, kpssk3, infecting carbapenem-resistant Klebsiella pneumoniae

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has spread globally and emerged as an urgent public health threat. Bacteriophages are considered an effective weapon against multidrug-resistant pathogens. In this study, we report a novel lytic phage, kpssk3, which is able to lyse CRKP and degrade exopolysaccharide (EPS). The morphological characteristics of kpssk3 observed by transmission electron microscopy, including a polyhedral head and a short tail, indicate that it belongs to the family Podoviridae. A one-step growth curve revealed that kpssk3 has a latent period of 10 min and a burst size of 200 plaque-forming units (pfu) per cell. kpssk3 was able to lyse 25 out of 27 (92.59%) clinically isolated CRKP strains, and it also exhibited high stability to changes in temperature and pH. kpssk3 has a linear dsDNA genome of 40,539 bp with 52.80% G+C content and 42 putative open reading frames (ORFs). No antibiotic resistance genes, virulence factors, or integrases were identified in the genome. Based on bioinformatic analysis, the tail fiber protein of phage kpssk3 was speculated to possess depolymerase activity towards EPS. By comparative genomics and phylogenetic analysis, it was determined that kpssk3 is a new T7-like virus and belongs to the subfamily Autographivirinae. The characterization and genomic analysis of kpssk3 will promote our understanding of phage biology and diversity and provide a potential strategy for controlling CRKP infection.

OmpK36-mediated Carbapenem resistance attenuates ST258 Klebsiella pneumoniae in vivo

Carbapenem-resistance in Klebsiella pneumoniae (KP) sequence type ST258 is mediated by carbapenemases (e.g. KPC-2) and loss or modification of the major non-selective porins OmpK35 and OmpK36. However, the mechanism underpinning OmpK36-mediated resistance and consequences of these changes on pathogenicity remain unknown. By solving the crystal structure of a clinical ST258 OmpK36 variant we provide direct structural evidence of pore constriction, mediated by a di-amino acid (Gly115-Asp116) insertion into loop 3, restricting diffusion of both nutrients (e.g. lactose) and Carbapenems. In the presence of KPC-2 this results in a 16-fold increase in MIC to Meropenem. Additionally, the Gly-Asp insertion impairs bacterial growth in lactose-containing medium and confers a significant in vivo fitness cost in a murine model of ventilator-associated pneumonia. Our data suggests that the continuous selective pressure imposed by widespread Carbapenem utilisation in hospital settings drives the expansion of KP expressing Gly-Asp insertion mutants, despite an associated fitness cost.

Carbapenem-resistance in Klebsiella pneumoniae sequence type ST258 can be enhanced by modification of the porins OmpK35 and OmpK36. Here, Wong et al. solve the crystal structure of a clinical ST258 OmpK36 variant, elucidating the mechanism of resistance and consequences on pathogenicity in vivo.

Economic burden of antibiotic resistance in ESKAPE organisms: a systematic review

Background

Antibiotic resistance (ABR) is one of the biggest threats to global health. Infections by ESKAPE (Enterococcus, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, and E. coli) organisms are the leading cause of healthcare-acquired infections worldwide. ABR in ESKAPE organisms is usually associated with significant higher morbidity, mortality, as well as economic burden. Directing attention towards the ESKAPE organisms can help us to better combat the wide challenge of ABR, especially multi-drug resistance (MDR).

Objective

This study aims to systematically review and evaluate the evidence of the economic consequences of ABR or MDR ESKAPE organisms compared with susceptible cases or control patients without infection/colonization in order to determine the impact of ABR on economic burden.

Methods

Both English-language databases and Chinese-language databases up to 16 January, 2019 were searched to identify relevant studies assessing the economic burden of ABR. Studies reported hospital costs (charges) or antibiotic cost during the entire hospitalization and during the period before/after culture among patients with ABR or MDR ESKAPE organisms were included. The costs were converted into 2015 United States Dollars. Disagreements were resolved by a third reviewer.

Results

Of 13,693 studies identified, 83 eligible studies were included in our review. The most studied organism was S. aureus, followed by Enterococcus, A. baumannii, E. coli, E. coli or/and K. pneumoniae, P. aeruginosa, and K. pneumoniae. There were 71 studies on total hospital cost or charge, 12 on antibiotic cost, 11 on hospital cost or charge after culture, 4 on ICU cost, 2 on hospital cost or charge before culture, and 2 on total direct and indirect cost. In general, ABR or MDR ESKAPE organisms are significantly associated with higher economic burden than those with susceptible organisms or those without infection or colonization. Nonetheless, there were no differences in a few studies between the two groups on total hospital cost or charge (16 studies), antibiotic cost (one study), hospital cost before culture (one study), hospital cost after culture (one study). Even, one reported that costs associated with MSSA infection were higher than the costs for similar MRSA cases.

Conclusions

ABR in ESKAPE organisms is not always, but usually, associated with significantly higher economic burden. The results without significant differences may lack statistical power to detect a significant association. In addition, study design which controls for severity of illness and same empirical antibiotic therapy in the two groups would be expected to bias the study towards a similar, even negative result. The review also highlights key areas where further research is needed.

The Clinical and Economic Impact of Antibiotic Resistance in China: A Systematic Review and Meta-Analysis

Antibiotic resistance (ABR) is one of the biggest threats to global health, especially in China. This study aims to analyze the published literature on the clinical and economic impact of ABR or multi-drug resistant (MDR) bacteria compared to susceptible bacteria or non-infection, in mainland China. English and Chinese databases were searched to identify relevant studies evaluating mortality, hospital stay, and hospital costs of ABR. A meta-analysis of mortality was performed using a random effects model. The costs were converted into 2015 United States (US) dollars. Of 13,693 studies identified, 44 eligible studies were included. Twenty-nine investigated the impact of ABR on hospital mortality, 37 were focused on hospital stay, and 21 on hospital costs. Patients with ABR were associated with a greater risk of overall mortality compared to those with susceptibility or those without infection (odds ratio: 2.67 and 3.29, 95% confidence interval: 2.18–3.26 and 1.71–6.33, p < 0.001 and p < 0.001, respectively). The extra mean total hospital stay and total hospital cost were reported, ranging from 3 to 46 days, and from US$238 to US$16,496, respectively. Our study indicates that ABR is associated with significantly higher mortality. Moreover, ABR is not always, but usually, associated with significantly longer hospital stay and higher hospital costs.

The Attributable Direct Medical Cost of Healthcare Associated Infection Caused by Multidrug Resistance Organisms in 68 Hospitals of China

Healthcare associated infection (HAI) is known to increase the economic burden of patients while the medical cost due to MDRO HAI is even higher. Three hundred eighty-one multidrug resistance organisms (MDROs) healthcare associated infection (HAI) case-patients and three hundred eighty-one matched control-patients were identified between January and December in 2015. The average total hospitalization medical cost of the case group was $6127.65 and that of the control group was $2274.02. The difference between the case group and the control group was statistically significant (t = 21.07; P < 0.01). The attributable cost of MDRO HAI was $3853.63. The direct medical costs due to different MDRO infections were different. The increased medical costs of CR-AB, CR-KP, and CR-PA were significantly higher than that of MRSA, MRSE, ESBL E. coli, and ESBL Kp (P < 0. 05). Among the subitem expenses, the drug cost increased the most (the average cost was $1457.72), followed by the treatment fee and test fee; the differences were statistically significant (P < 0.01).