A Retrospective Analysis of Risk Factors and Outcomes of Carbapenem-Resistant Klebsiella pneumoniae Bacteremia in Nontransplant Patients

Risk factors for multidrug-resistant and carbapenem-resistant Klebsiella pneumoniae bloodstream infections in Shanghai: A five-year retrospective cohort study

BACKGROUND

Multidrug-resistant Klebsiella pneumoniae (MDRKP) and carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infections (BSIs) account for significant mortality and healthcare costs.

OBJECTIVES

To investigate risk factors for MDRKP and CRKP BSIs.

METHODS

A retrospective analysis of inpatients with Klebsiella pneumoniae bloodstream infections (KP BSIs) was conducted in a tertiary care hospital in Shanghai from 01/01/2018-31/12/2022. Temporal distribution of mortality and department distribution of KP BSIs were assessed. A generalized linear model was used to determine risk factors for MDRKP and CRKP BSIs.

RESULTS

A total of 379 inpatients with KP BSIs were included. The proportion of death for KP BSIs, MDRKP BSIs and CRKP BSIs gradually decreased since 2020. Majority of both MDRKP and CRKP BSIs patients were from Intensive Care Unit (ICU), burn unit, hematology and pancreatic surgery. Genitourinary disorders, invasive ventilator, history of antibiotic use, and carbapenem use were independently associated with MDRKP BSIs. Respiratory disease, gastric tubes, carbapenem use and its quantity were independently associated with CRKP BSIs.

CONCLUSIONS

ICU, burn unit, hematology and pancreatic surgery are common departments for MDRKP and CRKP BSIs. Genitourinary disorders, respiratory disorders, invasive ventilator, gastric tubes and antibiotic use (carbapenems in particular) within 90 days prior to onset of BSIs are independently associated with MDRKP and CRKP BSIs.

Seven-year change of prevalence, clinical risk factors, and mortality of patients with carbapenem-resistant Klebsiella pneumoniae bloodstream infection in a Chinese teaching hospital: a case-case-control study

Carbapenem-resistant Klebsiella pneumoniae bloodstream infection (CRKP-BSI) is a major public health threat worldwide. CRKP-BSI is associated with poor outcomes, elevated morbidity and mortality, and high healthcare costs. Therefore, the identification of risk factors for CRKP-BSI and mortality are critical for preventing and controlling CRKP in hospitals. This retrospective case-case-control study was conducted at General Hospital of Tianjin Medical University, a tertiary teaching hospital, from 2017 to 2023. It included 105 patients with CRKP-BSI (case group 1) and matched 105 patients with carbapenem-susceptible K. pneumoniae bloodstream infection (CSKP-BSI) (case group 2). The control group was selected at a ratio of 1:1:1 (case group 1: case group 2: control) from patients with a positive blood culture (except for K. pneumoniae infection) to analyze risk factors associated with the two case groups and compare the 30-day survival curves using multivariable logistic regression and Kaplan-Meier analyses. Multivariate analysis revealed that liver disease was a risk factor for K. pneumoniae-BSI, and exposure to carbapenem [odds ratio (OR) = 3.24], tigecycline (OR = 3.43), and glucocorticoids (OR = 4.64) were independent risk factors for CRKP-BSI. The 30-day mortality of the CRKP-BSI group was 30.5%, and patient groups, respiratory diseases (HR = 3.52), use of 3rd-generation cephalosporins (HR = 1.92), mechanical ventilation (HR = 2.14), and central venous catheter insertion (HR = 2.85) were independent risk factors, whereas a shorter length of hospitalization was a protective factor for 30-day mortality. The in-hospital mortality in the CRKP-BSI group was 55.2%, and arterial catheter use (OR = 3.76) was an independent risk factor for in-hospital mortality. Several factors were identified to contribute to the development of CRKP-BSI. CRKP isolates were resistant to most antibiotics. Reducing CRKP-BSI-related mortality requires comprehensive consideration of underlying diseases, judicious antibiotic use, and invasive procedures. The high morbidity, mortality, along with the limited therapeutic options for CRKP-BSI, underscore the need for improved detection, identification of risk factors to develop effective preventive measures, and development of novel agents with reliable clinical efficacy against CRKP.

Role of CRISPR-cas system on virulence traits and carbapenem resistance in clinical Klebsiella pneumoniae isolates

BACKGROUND AND OBJECTIVES

The bacterial adaptive immune system known as CRISPR-Cas (clustered regularly interspersed short palindromic repeats-CRISPR-associated protein) is engaged in defense against various mobile genetic elements (MGEs) such as plasmids and bacteriophages. The purpose of this study was to characterize the CRISPR-Cas systems in carbapenem-resistant Klebsiella pneumoniae isolates and assess any possible correlation between these systems with antibiotic susceptibility, biofilm formation, and bacterial virulence.

MATERIALS AND METHODS

A total of 156 CRKP isolates were collected from different specimens of the inpatients. Biofilm formation and antibiotic susceptibility testing were evaluated using standard methods. Furthermore, the CRISPR-Cas system subtype genes, 11 carbapenemase genes, and 17 virulence genes were identified using separate standard PCR reactions. The diversity of the isolates was determined by random amplified polymorphic DNA (RAPD)-PCR.

RESULTS

The development of biofilms and antibiotic susceptibility of several CRKP isolates were significantly correlated with the absence or presence of the CRISPR-Cas system. PCR analysis of carbapenemase genes revealed that the frequency of the blaNDM-1 gene was significantly higher in the isolates with the subtype I-E CRISPR-Cas system. Moreover, the isolates with the subtype I-E CRISPR-Cas system exhibited a propensity to possess more virulence genes such as allS, k2A, wcaG, aerobactin, rmpA, iroN, magA, rmpA2, kfu, iutA, iucB, ybtS, repA, and terW.

CONCLUSION

CRISPR-Cas systems could affect the antibiotic susceptibility, capacity for biofilm formation, and virulence of Klebsiella pneumoniae. Our findings showed that the isolates containing the CRISPR-Cas system were moderate or strong biofilm producers and had a higher frequency of virulence genes.

Molecular Epidemiological Characteristics of bla IMP-4-Carrying Klebsiella pneumoniae ST-11 in Hospitalized Patients

Purpose

To investigate the molecular epidemiology and risk factors of carbapenem-resistant Klebsiella pneumoniae (CRKP) infection.

Patients and Methods

Patient's clinical data and CRKP strains were collected from November 2017 to December 2018 at a tertiary hospital in Wuhan, China. The antimicrobial susceptibilities, carbapenem-resistant genes, multi-locus sequence typing (MLST), homologous analysis, and risk factors for CRKP were determined.

Results

A total of 203 CRKP strains were isolated, and 98.5% (200/203) of patients were nosocomially infected. The mortality rate was 17.7% (36/203). All 203 strains were confirmed as carbapenemases -producing strains. The most predominant carbapenemase gene was bla IMP-4 (81.3%, 165/203), followed by bla KPC-2 (25.1%, 51/203) and bla NDM-1 (23.2%, 47/205). Of the 203 strains, 28 (13.8%) had both bla KPC-2 and bla IMP-4 genes, 23 (11.3%) had both bla IMP-4 and bla NDM-1 genes, 20 (9.9%) had bla KPC-2, bla IMP-4 and bla NDM-1 three genes. MLST analysis showed that there were 48 ST typologies (including 7 new STs), of which ST-11 was the most prevalent (59.6%, 121/203). Phylogenetic analysis showed that 203 CRKP isolates came from 7 clusters and exhibited a strong correlation with the isolation source. eBURST analyses indicated that CRKP isolates have undergone different evolutionary processes. Patients with ST-11 CRKP underwent more mechanical ventilation (50% vs 32.9%, P=0.020) and gastric catheterization (15.7% vs 6.1%, P=0.042) within 3 months before sample collection, and also had higher drug-resistance rate than non-ST-11 CRKP. Comparing with CSKP (carbapenem-sensitive Klebsiella pneumoniae), gastrointestinal disease (odds ratio [OR]=6.168, P=0.003), nosocomial infection (OR=5.573, P=0.012), antibiotic exposure (OR=4.131, P=0.004), urinary catheterization (OR=3.960, P=0.031) and venous/arterial catheterization (OR=2.738, P=0.026) within the preceding 3 months were independent risk factors for CRKP infection.

Conclusion

The IMP-4 was the most predominant carbapenemase and bla IMP-4 bearing Klebsiella pneumoniae ST-11 was spreading in the hospital. Nosocomial infections, antibiotic exposure, and urinary and venous/arterial catheterization within 3 months were the risk factors for developing CRKP infection.

Development and validation of a nomogram-based risk prediction model for carbapenem-resistant Klebsiella pneumoniae in hospitalized patients

Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses one of the major challenges in clinical anti-infective therapy worldwide. This retrospective cohort study at a tertiary general hospital in Wuhan aimed to identify risk factors for hospital-acquired CRKP infections among 1,113 patients. All participants were aged 18 years and above, and had confirmed positive cultures for KP isolated within 48 hours post-hospitalization. Independent risk factors were identified using LASSO logistic regression and incorporated into a predictive nomogram. The factors included in the nomogram were prior carbapenem exposure, prior β-lactams-β-lactamase inhibitor combination (BLBLI) exposure, prior intensive care unit (ICU) stay, and prior mechanical ventilation. The areas under the receiver operating characteristic curve (AUC) for the nomogram were 0.793 in the training group (70% of patients) and 0.788 in the validation group (30% of patients), demonstrating its discriminatory power and predictive accuracy. The P values for the Hosmer-Lemeshow test were 0.333 and 0.684, indicating good calibration. The clinical utility of the nomogram was further supported by decision curve analysis (DCA) and clinical impact curve (CIC), demonstrating its potential to guide clinical decision-making. Our retrospective analysis identified key risk factors for CRKP infection and developed a nomogram that could effectively predict CRKP infections in hospitalized patients. Although the single-center nature of this study limits generalizability, the nomogram provides a foundation for future prospective, multicenter validations.IMPORTANCEWe established a nomogram scoring system that incorporates four key risk factors: prior carbapenem exposure, prior β-lactams-β-lactamase inhibitor combination (BLBLI) exposure, prior intensive care unit (ICU) stay, and prior mechanical ventilation. This nomogram demonstrated strong discriminatory power, excellent calibration, and significant clinical utility. This study highlights the critical risk factors associated with hospital-acquired carbapenem-resistant Klebsiella pneumoniae (CRKP) infections, providing valuable insights for clinicians to identify high-risk patients.

Association between clinical-biological characteristics of Klebsiella pneumoniae and 28-day mortality in patients with bloodstream infection

BACKGROUND

Klebsiella pneumoniae bloodstream infection (KP BSI) is a severe clinical condition characterized by high mortality rates. Despite the clinical significance, accurate predictors of mortality in KP BSI have yet to be fully identified.

METHODS

A retrospective analysis was conducted on the clinical data of 90 cases of KP BSI. The clinical data was extracted from electronic medical records. Antimicrobial susceptibility testing, string testing, and whole-genome sequencing (WGS) were performed on all isolates. Additionally, relevant bioinformatics analyses, such as phylogenetic analysis and assessment of resistance and virulence genes, were carried out. Logistic regression modeling was employed to evaluate the risk factors associated with 28-day mortality in patients with KP BSI, considering both host characteristics and the characteristics of the causative Klebsiella pneumoniae (KP) isolates.

RESULTS

Among the 90 patients included in this study, the 28-day mortality rate for those with KP BSI was 30.00% (27/90). Multivariate analysis revealed several host-related factors associated with an increased risk of 28-day mortality. These factors included an elevated qSOFA score (odds ratio [OR] 2.98, 95% confidence interval [CI] 1.21-7.31, p = 0.017), presence of septic shock (OR 8.21, 95% CI 1.63-41.93, p = 0.008), and nosocomial infection (OR 7.72, 95% CI 1.71-34.74, p = 0.002). Regarding bacterial factors, the presence of the virulence genes rfbA/B/D (OR 8.53, 95% CI 1.41-51.57, p = 0.020) was identified as an independent risk factor, particularly for nosocomial infection patients. However, hypermucoviscosity phenotype, ST type, serotype, and resistance genes were not associated with an increased risk of 28-day mortality.

CONCLUSION

The carriage of virulence genes rfbA/B/D, which is responsible for the synthesis of O-antigen, was associated with poor prognosis of KP BSI. It may facilitate the clinical management of patients with bloodstream infection (BSI) caused by hypervirulent KP strains, especially those with rfbA/B/D genes.

CLINICAL TRIAL NUMBER

Not applicable.

Economic and human burden attributable to antimicrobial resistance in Spain: a holistic macro-estimation of costs

Antimicrobial resistance (AMR) represents a major threat to medical practice, complicating infection management, and increasing mortality and healthcare costs. Macro estimations of this health issue remain underexplored because data are currently limited to hospital systems. This study aims to estimate the economic and human burden of AMR in Spain at a macro level. An economic model was constructed based on prevalence rates, premature deaths and published literature to assess costs. Methodology was based on several techniques depending on the type of cost to be estimated: hospital inpatient care costs (based on extra hospital days); outpatient care costs (employing reimbursement rates from regional health services); productivity losses due to premature deaths (using the Human Capital Approach) and morbidity (based on days absent from work). Using data from EARS-NET, ESAC-NET and GBD, a total of 30 bacteria-drug resistance combinations were analysed. The results showed that 77,870 infections, 6,199 premature deaths, and 426,495 extra hospital days were attributable to AMR in Spain, mostly due to Gram-negative bacteria. AMR was also responsible for 3,112 years of working life lost. The costs reached EUR 338.6 million (0.03% of GDP), costing each Spaniard EUR 7.15 per year. Direct costs accounted for 72% of total costs, while indirect costs represented 28%. To date, this is the first study that evaluates the cost of AMR across such a wide range of bacteria and infection sites. These estimates are useful for approximating the problem and for planning containment and action strategies.

Incidence, antimicrobial resistance and mortality of Klebsiella pneumoniae bacteraemia in Shanghai, China, 2018-2022

BACKGROUND

Klebsiella pneumoniae (KP) accounts for high antimicrobial resistance and mortality rates of bloodstream infections (BSIs).

OBJECTIVES

To investigate incidence, antimicrobial resistance and risk factors for mortality of KP BSIs in East China.

METHODS

A retrospective study of patients with KP BSIs was conducted in a tertiary care hospital from 2018 to 2022. Medical records of all hospitalised patients with KP BSIs were reviewed and analysed. The incidence, antimicrobial resistance and mortality of KP BSIs were evaluated. The Kaplan-Meier method was used to plot survival curves and logistic regression was used to analyse risk factors for crude 30-day mortality.

RESULTS

A total of 379 inpatients with KP BSIs were enrolled. The incidence of patients with KP BSIs was fluctuating between 4.77 and 9.40 per 100,000 patient-days. The crude 30-day mortality rate of these patients was 26.39%. Of the 379 KPisolates, 197 (51.98%) were carbapenem-resistant (CR) and 252 (66.49%) were multidrug-resistant (MDR). All isolates showed the lowest resistance to tigecycline (13.77%) and polymyxin B (14.61%). Cases with MDR/CR isolates had significantly longer length of hospital stay, higher crude 30-day mortality and medical costs than non-MDR/non-CR isolates. Age, CR phenotype, paracentesis, indwelling central venous catheter (CVC), use of carbapenems, tetracyclines, polymyxins B, and irrational empiric treatment were independently associated with crude 30-day mortality.

CONCLUSION

MDR/CR KP BSIs are associated with increased mortality, healthcare costs and prolonged hospitalisation. Patients with advanced age, CR phenotype, paracentesis, CVC, exposure to some antibiotics, and irrational empirical antibiotic treatment are at higher mortality risk.

Development of prediction models for carbapenem-resistant Klebsiella pneumoniae acquisition and prognosis in adult patients

Objectives

To explore the risk factors and clinical outcomes of carbapenem-resistant Klebsiella pneumoniae (CRKP) infection and establish nomograms to predict the probability of CRKP infection and mortality in adult patients.

Methods

Patients infected with KP from August 2019 to April 2021 in a tertiary hospital in Shanghai were enrolled. Risk factors associated with CRKP and 30-day mortality were identified using multivariate logistic regression analysis and Cox regression analysis.

Results

Overall, 467 patients with KP infection were enrolled, wherein 210 (45.0%) patients were infected with CRKP and 257 (55.0%) patients with carbapenem-susceptible K. pneumoniae (CSKP). Five factors, namely Charlson's Comorbidity Index (CCI) ≥ 3, the use of central venous catheterization, prior hospitalization during the 3 months before infection, and previous exposure to carbapenems and broad-spectrum β-lactams, were found to be independently associated with CRKP infection. Based on these parameters, the nomogram showed a better performance as indicated by C-index of 0.94 (95% confidence interval [CI]: 0.92-0.96) and well-fitted calibration curves. CRKP was independently associated with 30-day mortality. Multivariate Cox regression analysis revealed that age ≥65 years, higher CCI scores, higher Sequential Organ Failure Assessment scores, the presence of respiratory failure, albumin levels ≤30 g/L, and non-appropriate treatments in 3 days, were associated with 30-day mortality.

Conclusion

The predictive nomogram established in this study can facilitate the clinicians to make better clinical decisions when treating patients with KP infection.

Clinical Characteristics of K. pneumoniae Related Endogenous Endophthalmitis in China

Purpose

To investigate the clinical characteristics and systemic risk factors of K. pneumoniae related endogenous endophthalmitis (KPREE) in China and explore the possible pathophysiological mechanisms.

Methods

This was a retrospective comparative study. All enrolled KPREE patients were followed up for at least 1 month to observe their clinical characteristics, unfavorable prognosis, and risk factors, and were compared with intraocular surgery-related postoperative endophthalmitis (ISRPE).

Results

Finally, a total of 15 eyes (3 both eyes) from 12 patients were enrolled in KPREE group, and 11 eyes (none both eyes) from 11 patients were enrolled in ISRPE group. Compared to the ISRPE group, the KPREE group had a higher percentage of fever (100% vs 9.09%, P = 0.000), liver abscess (91.67% vs 0%, P = 0.000), lung involvement (50.00% vs 0%, P = 0.024), and lower plasma albumin levels (24.1 [17.8, 31.7] vs 44.0 [37.7, 48.4], P = 0.001). Furthermore, Pearson's partial correlation analysis showed that fever (adjusted r = 0.592, adjusted P = 0.026) and plasma albumin (adjusted r = -0.658, adjusted P = 0.011) were independent factors associated with KPREE. In the KPREE group, ten eyes received 1-3 intravitreal antibiotic injections within one month. In the ten eyes that underwent injections, due to poor treatment reaction, four eyes experienced evisceration, and two eyes underwent vitrectomy with silicone oil tamponade at 1-month follow-up. And one eye developed sympathetic ophthalmia at 8-month visit.

Conclusions

Patients with K. pneumoniae infection with hypoproteinemia or fever should be highly vigilant about the occurrence of KPREE, and more attention should be paid to the contralateral risk of KPREE or sympathetic ophthalmia.

Risk factors for bloodstream infections due to carbapenem-resistant Enterobacterales: a nested case-control-control study

BACKGROUND

Carbapenem-resistant Enterobacterales (CRE) bloodstream infections (BSIs) are a major threat to patients. To date, data on risk factors have been limited, with low internal and external validity. In this multicentre study, risk factors for CRE BSI were determined by comparison with two control groups: patients with carbapenem-susceptible Enterobacterales (CSE) BSI, and patients without Enterobacterales infection (uninfected patients).

METHODS

A multicentre, case-control-control study was nested in a European prospective cohort study on CRE (EURECA). CRE BSI:CSE BSI matching was 1:1, CRE BSI:Uninfected patients matching was 1:3, based on hospital, ward and length of stay. Conditional logistic regression was applied.

RESULTS

From March 2016 to November 2018, 73 CRE BSIs, 73 CSE BSIs and 219 uninfected patients were included from 18 European hospitals. For CRE versus CSE BSI, previous CRE colonization/infection [incidence rate ratio (IRR) 7.32; 95% CI 1.65-32.38) increased the risk. For CRE versus uninfected controls, independent risk factors included: older age (IRR 1.03; 95% CI 1.01-1.06), patient referral (long-term care facility: IRR 7.19; 95% CI 1.51-34.24; acute care hospital: IRR 5.26; 95% CI 1.61-17.11), previous colonization/infection with other MDR organisms (MDROs) (IRR 9.71; 95% CI 2.33-40.56), haemodialysis (IRR 8.59; 95% CI 1.82-40.53), invasive procedures (IRR 5.66; 95% CI 2.11-15.16), and β-lactam/β-lactamase inhibitor combinations (IRR 3.92; 95% CI 1.68-9.13) or third/fourth generation cephalosporin (IRR 2.75; 95% CI 1.06-7.11) exposure within 3 months before enrolment.

CONCLUSIONS

Evidence of previous CRE colonization/infection was a major risk factor for carbapenem resistance among Enterobacterales BSI. Compared with uninfected patients, evidence of previous MDRO colonization/infection and healthcare exposure were important risk factors for CRE BSI. Targeted screening, infection prevention and antimicrobial stewardship should focus on these high-risk patients.

Retrospective analysis of molecular characteristics, risk factors, and outcomes in carbapenem-resistant Klebsiella pneumoniae bloodstream infections

BACKGROUND

Klebsiella pneumoniae (KP) is the second most prevalent Gram-negative bacterium causing bloodstream infections (BSIs). In recent years, the management of BSIs caused by KP has become increasingly complex due to the emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP). Although numerous studies have explored the risk factors for the development of CRKP-BSIs, the mortality of patients with KP-BSIs, and the molecular epidemiological characteristics of CRKP, the variability in data across different populations, countries, and hospitals has led to inconsistent conclusions. In this single-center retrospective observational study, we utilized logistic regression analyses to identify independent risk factors for CRKP-BSIs and factors associated with mortality in KP-BSI patients. Furthermore, a risk factor-based prediction model was developed. CRKP isolates underwent whole-genome sequencing (WGS), followed by an evaluation of microbiological characteristics, including antimicrobial resistance and virulence genes, as well as epidemiological characteristics and phylogenetic analysis.

RESULTS

Our study included a total of 134 patients with KP-BSIs, comprising 50 individuals infected with CRKP and 84 with carbapenem-susceptible Klebsiella pneumoniae (CSKP). The independent risk factors for CRKP-BSIs were identified as gastric catheterization (OR = 9.143; CI = 1.357-61.618; P = 0.023), prior ICU hospitalization (OR = 4.642; CI = 1.312-16.422; P = 0.017), and detection of CRKP in non-blood sites (OR = 8.112; CI = 2.130-30.894; P = 0.002). Multivariate analysis revealed that microbiologic eradication after 6 days (OR = 3.569; CI = 1.119-11.387; P = 0.032), high Pitt bacteremia score (OR = 1.609; CI = 1.226-2.111; P = 0.001), and inappropriate empirical treatment after BSIs (OR = 6.756; CI = 1.922-23.753; P = 0.003) were independent risk factors for the 28-day mortality in KP-BSIs. The prediction model confirmed that microbiologic eradication after 6.5 days and a Pitt bacteremia score of 4.5 or higher were significant predictors of the 28-day mortality. Bioinformatics analysis identified ST11 as the predominant CRKP sequence type, with blaKPC-2 as the most prevalent gene variant. CRKP stains carried multiple plasmid-mediated resistance genes along with some virulence genes. Phylogenetic analysis indicated the presence of nosocomial transmission of ST11 CRKP within the ICU.

CONCLUSIONS

The analysis of risk factors for developing CRKP-BSIs and the association between KP-BSIs and 28-day mortality, along with the development of a risk factor-based prediction model and the characterization of CRKP strains, enhances clinicians' understanding of the pathogens responsible for BSIs. This understanding may help in the timely administration of antibiotic therapy for patients with suspected KP-BSIs, potentially improving outcomes.

Development and validation of a prognostic nomogram to predict 30-day all-cause mortality in patients with CRO infection treated with colistin sulfate

Background

Carbapenem-resistant Gram-negative organism (CRO) infection is a critical clinical disease with high mortality rates. The 30-day mortality rate following antibiotic treatment serves as a benchmark for assessing the quality of care. Colistin sulfate is currently considered the last resort therapy against infections caused by CRO. Nevertheless, there is a scarcity of reliable tools for personalized prognosis of CRO infections. This study aimed to develop and validate a nomogram to predict the 30-day all-cause mortality in patients with CRO infection who underwent colistin sulfate treatment.

Methods

A prediction model was developed and preliminarily validated using CRO-infected patients treated with colistin sulfate at Tongji Hospital in Wuhan, China, who were hospitalized between May 2018 and May 2023, forming the study cohort. Patients admitted to Xianning Central Hospital in Xianning, China, between May 2018 and May 2023 were considered for external validation. Multivariate logistic regression was performed to identify independent predictors and establish a nomogram to predict the occurrence of 30-day all-cause mortality. The receiver operating characteristic (ROC) curve, the area under the ROC curve (AUC), and the calibration curve were used to evaluate model performance. The decision curve analysis (DCA) was used to assess the model clinical utility.

Results

A total of 170 patients in the study cohort and 65 patients in the external validation cohort were included. Factors such as age, duration of combination therapy, nasogastric tube placement, history of previous surgery, presence of polymicrobial infections, and occurrence of septic shock were independently associated with 30-day all-cause mortality and were used to construct the nomogram. The AUC of the nomogram constructed from the above six factors was 0.888 in the training set. The Hosmer-Lemeshow test showed that the model was a good fit (p = 0.944). The calibration curve of the nomogram was close to the ideal diagonal line. Furthermore, the decision curve analysis demonstrated significantly better net benefit in the model. The external validation proved the reliability of the prediction nomogram.

Conclusion

A nomogram was developed and validated to predict the occurrence of 30-day all-cause mortality in patients with CRO infection treated with colistin sulfate. This nomogram offers healthcare providers a precise and efficient means for early prediction, treatment management, and patient notification in cases of CRO infection treated with colistin sulfate.

Mortality associated with carbapenem resistance in Klebsiella pneumoniae bloodstream infection: A propensity score-matched study

OBJECTIVE

Klebsiella pneumoniae are common pathogens causing bloodstream infection (BSI) that increasingly express carbapenem resistance worldwide. To date, no study has precisely investigated the impact of carbapenem resistance in K. pneumoniae (CRKP) BSI on mortality.

METHODS

This retrospective study included 87 patients with CRKP BSI and 321 patients with carbapenem-susceptible K. pneumoniae (CSKP) BSI from 2015 to 2020. Propensity score analyses with stabilized inverse probability of treatment weighting (IPTW-S) was applied to balance covariates. The hazard ratio for 30-day mortality associated with carbapenem resistance was estimated using Cox regression and Kaplan-Meier curves.

RESULTS

The 30-day crude mortality rates were 43.7% in patients with CRKP BSI and 17.8% in patients with CSKP BSI (P < .001). Age ≥55 years, underlying hematological malignancies and hemodialysis were independently associated with mortality in CRKP BSI. A skin or soft-tissue infection source, urinary catheter, and underlying chronic obstructive pulmonary disease were predictors of mortality in CSKP BSI. The group characteristics were well balanced after IPTW-S. The adjusted hazard ratio for 30-day mortality for CRKP BSI was 1.607 (interquartile range, 0.814-3.171).

CONCLUSIONS

Carbapenem resistance was not associated with a significant increase in 30-day mortality in KP BSI; patient and disease factors were primary determinants of outcomes.

Socioeconomic Burden of Pyogenic Liver Abscess Caused by Klebsiella Pneumoniae from a Teaching Hospital in East China

Background

The prevalence of pyogenic liver abscess (PLA) is increasing worldwide. However, evaluation on its economic burden is still lack.

Methods

A retrospective study that included all patients identified PLA from 2017 to 2020 was conducted. Clinical information and hospital costs were collected through the electronic medical records. We evaluated the economic burden using disability-adjusted life years (DALYs). Differences in socioeconomic burdens between Klebsiella pneumoniae-caused liver abscesses (KPLA) and non-Klebsiella pneumoniae-caused liver abscesses (non-KPLA) were compared.

Results

We found 327 patients identified PLA in the study, including 146 with KPLA and 181 with non-KPLA. The demographic characteristics, median hospital stay, severity, and in-hospital mortality were similar between the two groups. The median total in-hospital cost was higher in the non-KPLA than in the KPLA group, although no statistical difference was found ($3607.2 vs $3424.6; P = 0.446). The median DALY loss was significantly higher in the KPLA than in the non-KPLA group [1.49 (0.97-2.30) vs 1.27 (0.87-1.89); P = 0.033)], and male patients presented a higher average DALY loss than female patients. KPLA had a substantially greater median indirect economic loss than the non-KPLA group [$1442.8 (915.9-17,221.5) vs $1232.5 (764.6-15,473.0); P = 0.028], and indirect economic loss exhibited a significant increase from 2017 to 2020 in patients with PLA. No differences were found in the socioeconomic burden between the two groups [$8019.6 (4200.3-21,832.1) vs $7436.4 (4023.2-19,063.9); P = 0.172].

Conclusion

The economic burden of PLA is significant, particularly in patients with KP. Patients with KPLA experienced increased DALY loss and indirect economic loss than non-KPLA. PLA must be prioritized as the indirect economic burden rises annually.

CRISPR/Cas13-assisted carbapenem-resistant Klebsiella pneumoniae detection

BACKGROUND/PURPOSE

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is capable of causing serious community and hospital-acquired infections. However, currently, the identification of CRKP is complex and inefficient. Hence, this study aimed to develop methods for the early and effective identification of CRKP to allow reasonable antimicrobial therapy in a timely manner.

METHODS

K. pneumoniae (KP)-, K. pneumoniae carbapenemase (KPC)- and New Delhi metallo-β-lactamase (NDM)- specific CRISPR RNAs (crRNAs), polymerase chain reaction (PCR) primers and recombinase-aided amplification (RAA) primers were designed and screened in conserved sequence regions. We established fluorescence and lateral flow strip assays based on CRISPR/Cas13a combined with PCR and RAA, respectively, to assist in the detection of CRKP. Sixty-one clinical strains (including 51 CRKP strains and 10 carbapenem-sensitive strains) were collected for clinical validation.

RESULTS

Using the PCR-CRISPR assay, the limit of detection (LOD) for KP and the blaKPC and blaNDM genes reached 1 copy/μL with the fluorescence signal readout. Using the RAA-CRISPR assay, the LOD could reach 101 copies/μL with both the fluorescence signal readout and the lateral flow strip readout. Additionally, the positivity rates of CRKP-positive samples detected by the PCR/RAA-CRISPR fluorescence and RAA-CRISPR lateral flow strip methods was 92.16% (47/51). The sensitivity and specificity reached 100% for KP and blaKPC and blaNDM gene detection. For detection in a simulated environmental sample, 1 CFU/cm2 KP could be detected.

CONCLUSION

We established PCR/RAA-CRISPR assays for the detection of blaKPC and blaNDM carbapenemase genes, as well as KP, to facilitate the detection of CRKP.

The Global and Regional Prevalence of Hospital-Acquired Carbapenem-Resistant Klebsiella pneumoniae Infection: A Systematic Review and Meta-analysis

Background

Due to scarce therapeutic options, hospital-acquired infections caused by Klebsiella pneumoniae (KP), particularly carbapenem-resistant KP (CRKP), pose enormous threat to patients' health worldwide. This study aimed to characterize the epidemiology and risk factors of CRKP among nosocomial KP infections.

Method

MEDLINE, Embase, PubMed, and Google Scholar were searched for studies reporting CRKP prevalence from inception to 30 March 2023. Data from eligible publications were extracted and subjected to meta-analysis to obtain global, regional, and country-specific estimates. To determine the cause of heterogeneity among the selected studies, prespecified subgroup analyses and meta-regression were also performed. Odds ratios of CRKP-associated risk factors were pooled by a DerSimonian and Laird random-effects method.

Results

We retained 61 articles across 14 countries and territories. The global prevalence of CRKP among patients with KP infections was 28.69% (95% CI, 26.53%-30.86%). South Asia had the highest CRKP prevalence at 66.04% (95% CI, 54.22%-77.85%), while high-income North America had the lowest prevalence at 14.29% (95% CI, 6.50%-22.0%). In the country/territory level, Greece had the highest prevalence at 70.61% (95% CI, 56.77%-84.45%), followed by India at 67.62% (95% CI, 53.74%-81.79%) and Taiwan at 67.54% (95% CI, 58.65%-76.14%). Hospital-acquired CRKP infections were associated with the following factors: hematologic malignancies, corticosteroid therapies, intensive care unit stays, mechanical ventilations, central venous catheter implantations, previous hospitalization, and antibiotic-related exposures (antifungals, carbapenems, quinolones, and cephalosporins).

Conclusions

Study findings highlight the importance of routine surveillance to control carbapenem resistance and suggest that patients with nosocomial KP infection have a very high prevalence of CRKP.

Incidence, antimicrobial resistance and mortality of Pseudomonas aeruginosa bloodstream infections among hospitalized patients in China: a retrospective observational multicenter cohort study from 2017 to 2021

Background

Pseudomonas aeruginosa (P. aeruginosa) accounts for high antimicrobial resistance and mortality rates of bloodstream infections (BSIs). We aim to investigate incidence, antimicrobial resistance and risk factors for mortality of P. aeruginosa BSIs among inpatients.

Methods

A retrospective cohort study were conducted at two tertiary hospitals in 2017-2021. Medical and laboratory records of all inpatients diagnosed with P. aeruginosa BSIs were reviewed. A generalized linear mixed model was used to identify risk factors for mortality.

Results

A total of 285 patients with P. aeruginosa BSIs were identified. Incidence of P. aeruginosa BSIs fluctuated between 2.37 and 3.51 per 100,000 patient-days over the study period. Out of 285 P. aeruginosa isolates, 97 (34.04%) were carbapenem-resistant (CR) and 75 (26.32%) were multidrug-resistant (MDR). These isolates showed low resistance to aminoglycosides (9.51-11.62%), broad-spectrum cephalosporins (17.19-17.61%), fluoroquinolones (17.25-19.43%), and polymyxin B (1.69%). The crude 30-day mortality rate was 17.89% (51/285). Healthcare costs of patients with MDR/CR isolates were significantly higher than those of patients with non-MDR/CR isolates (P < 0.001/=0.002). Inappropriate definitive therapy [adjusted odds ratio (aOR) 4.47, 95% confidence interval (95% CI) 1.35-14.77; P = 0.014], ICU stay (aOR 2.89, 95% CI: 1.26-6.63; P = 0.012) and corticosteroids use (aOR 2.89, 95% CI: 1.31-6.41; P = 0.009) were independently associated with 30-day mortality.

Conclusion

Incidence of P. aeruginosa BSIs showed an upward trend during 2017-2020 but dropped in 2021. MDR/CR P. aeruginosa BSIs are associated with higher healthcare costs. Awareness is required that patients with inappropriate definitive antimicrobial therapy, ICU stay and corticosteroids use are at higher risk of death from P. aeruginosa BSIs.

Risk factors and molecular epidemiology of bloodstream infections due to carbapenem-resistant Klebsiella pneumoniae

PURPOSE

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is emerging as a worldwide public health concern; however, molecular epidemiological surveillance of clinical CRKP bloodstream infection (BSI) in China is limited. We conducted a retrospective observational study to assess risk factors and the molecular epidemiology of CRKP BSI.

METHODS

We reviewed the medical records of enrolled patients to assess risk factors of CRKP BSI. Characteristics of CRKP isolates were analyzed by whole genome sequencing and Kleborate. Evolutionary diversification in CRKP isolates was described through Single Nucleotide Polymorphisms analysis and phylogenetic tree construction.

RESULTS

We found that prior ICU hospitalization and use of carbapenems were independent risk factors for CRKP BSI. The main CRKP sequence type (ST) and capsular serotype were ST11 and KL64, and KPC-2 was the most prevalent enzyme type of carbapenemase-carrying Klebsiella pneumoniae. The most prevalent aerobactin and yersiniabactin of ST11-CRKP were iuc-1 and ybt9 ICEKp3, as for KL64-CRKP. Phylogenomic analysis showed that the antibacterial resistance genes on plasmids were highly consistent, but the genetic background of the chromosomes was still different.

CONCLUSIONS

Our findings are important for hospitals, allowing them to limit dissemination of CRKP and optimize antibiotic administration.

Development and validation of nomograms for predicting the risk probability of carbapenem resistance and 28-day all-cause mortality in gram-negative bacteremia among patients with hematological diseases

Objectives

Gram-negative bacteria (GNB) bloodstream infections (BSIs) are the most widespread and serious complications in hospitalized patients with hematological diseases. The emergence and prevalence of carbapenem-resistant (CR) pathogens has developed into a considerable challenge in clinical practice. Currently, nomograms have been extensively applied in the field of medicine to facilitate clinical diagnosis and treatment. The purpose of this study was to explore risk indicators predicting mortality and carbapenem resistance in hematological (HM) patients with GNB BSI and to construct two nomograms to achieve personalized prediction.

Methods

A single-center retrospective case-control study enrolled 244 hospitalized HM patients with GNB-BSI from January 2015 to December 2019. The least absolute shrinkage and selection operator (LASSO) regression analysis and multivariate logistic regression analysis were conducted to select potential characteristic predictors of plotting nomograms. Subsequently, to evaluate the prediction performance of the models, the prediction models were internally validated using the bootstrap approach (resampling = 1000) and 10-fold cross validation.

Results

Of all 244 eligible patients with BSI attributed to GNB in this study, 77 (31.6%) were resistant to carbapenems. The rate of carbapenem resistance exhibited a growing tendency year by year, from 20.4% in 2015 to 42.6% in 2019 (p = 0.004). The carbapenem resistance nomogram constructed with the parameters of hypoproteinemia, duration of neutropenia ≥ 6 days, previous exposure to carbapenems, and previous exposure to cephalosporin/β-lactamase inhibitors indicated a favorable discrimination ability with a modified concordance index (C-index) of 0.788 and 0.781 in both the bootstrapping and 10-fold cross validation procedures. The 28-day all-cause mortality was 28.3% (68/240). The prognosis nomogram plotted with the variables of hypoproteinemia, septic shock, isolation of CR-GNB, and the incomplete remission status of underlying diseases showed a superior discriminative ability of poorer clinical prognosis. The modified C-index of the prognosis nomogram was 0.873 with bootstrapping and 0.887 with 10-fold cross validation. The decision curve analysis (DCA) for two nomogram models both demonstrated better clinical practicality.

Conclusions

For clinicians, nomogram models were effective individualized risk prediction tools to facilitate the early identification of HM patients with GNB BSI at high risk of mortality and carbapenem resistance.

Prognostic Risk Factors of Carbapenem-Resistant Gram-Negative Bacteria Bloodstream Infection in Immunosuppressed Patients: A 7-Year Retrospective Cohort Study

Purpose

Carbapenem-resistant Gram-negative bacteria bloodstream infection (CRGNB-BSI) has gradually become a major threat worldwide due to its treatment difficulty and high mortality. This study aimed to determine the risk factors for CRGNB-BSI in immunosuppressed patients.

Patients and Methods

A total of 427 immunosuppressed patients with CRGNB-BSI were retrospectively investigated from 2015 to 2021. Both univariate and multivariate logistic regression analyses were applied to evaluate independent risk factors for CRGNB-BSI.

Results

The most common etiology was Klebsiella Pneumoniae (50.59%; 216/427), while the Acinetobacillus baumannii infection was associated with the highest mortality (58.25%) among all etiologies. The 60-day mortality of immunosuppressed patients with CRGNB-BSI was 52.48% (224/427). Procalcitonin (PCT) > 0.5 μg/L (OR = 2.32, 95% CI: 1.28-4.19, P = 0.005) and age > 55 years (OR = 2.06, 95% CI: 1.17-3.64, P = 0.012) were found to be predictors of 60-day mortality of CRGNB-BSI, and tigecycline regimen (OR = 3.20, 95% CI: 1.81-5.67, P < 0.001) was associated with higher mortality. Multivariate analysis also revealed that patients who developed acute kidney injury (AKI) (OR = 2.19, 95% CI: 1.11-4.30, P = 0.023), gastrointestinal bleeding (OR = 3.18, 95% CI: 1.10-9.16, P = 0.032), multiple organ dysfunction syndrome (MODS) (OR = 12.11, 95% CI: 2.61-56.19, P = 0.001), and septic shock (OR = 3.24, 95% CI: 1.77-5.94, P < 0.001) showed worse outcomes. The risk factors were also significantly associated with mortality in the different subgroups.

Conclusion

This study demonstrated that PCT > 0.5 μg/L, age > 55 years, and the tigecycline regimen were significantly associated with higher 60-day mortality among immunosuppressed patients with CRGNB- BSI. Patients developing MODS, septic shock, or AKI had worse clinical outcomes. .

Risk Factors and Clinical Impact of Carbapenem-Resistant Enterobacterales Coinfections Among Hospitalized Patients with Clostridioides difficile Infection

Introduction

The risk factors and clinical impact of carbapenem-resistant Enterobacterales (CRE) coinfection among hospitalized patients with Clostridioides difficile infection (CDI) were analyzed in this study.

Materials and Methods

A clinical study was performed at the medical wards of Tainan Hospital, Ministry of Health and Welfare in southern Taiwan. Patients with CDI between January 2013 and April 2020 were included.

Results

Among 238 patients included for analysis, 22 (9.2%) patients developed CRE coinfections within 14 days before or after the onset of CDI. CDI patients with CRE coinfection had longer hospitalization stays (103.0 ± 97.0 days vs 42.5 ± 109.6 days, P = 0.01) than those without CRE coinfection. In the multivariate analysis, age (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.01–1.10, P = 0.02) was independently associated with CRE coinfection. In contrast, underlying old stroke (OR 0.15, 95% CI 0.03–0.70, P = 0.02) was negatively linked to CRE coinfection.

Conclusion

Among patients with CDI, CRE coinfections were associated with prolonged hospitalization for CDI. Age was an independent risk factor for CRE coinfection among patients with CDI.

Clinical and Molecular Characterizations of Carbapenem-Resistant Klebsiella pneumoniae Causing Bloodstream Infection in a Chinese Hospital

Bloodstream infection (BSI) caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) is a serious and urgent threat for hospitalized patients. This study aims to describe the clinical and molecular characteristics of CRKP causing BSI in a tertiary-care hospital in Beijing, China. A total of 146 CRKP strains and 39 carbapenem-susceptible K. pneumoniae (CSKP) strains collected in the hospital from 2017 to 2020 were sent for whole-genome sequencing. Univariate and multivariate analyses were used to evaluate risk factors for in-hospital mortality of CRKP-BSI cases. Thirty (20.5%) of 146 CRKP-BSI patients and three (7.7%) of 39 CSKP-BSI patients died at discharge (χ² = 3.471, P = 0.062). Multivariate logistic regression analysis indicated that age and use of urinary catheters were independent risk factors for the death of CRKP-BSI. The 146 CRKP isolates belonged to 9 sequence types (STs) and 11 serotypes, while the 39 CSKP isolates belonged to 23 STs and 27 serotypes. The mechanism of carbapenem resistance for all the CRKP strains was the acquisition of carbapenemase, mainly KPC-2 (n = 127). There were 2 predominant serotypes for ST11 CRKP, namely, KL47 (n = 82) and KL64 (n = 42). Some virulent genes, including rmpA2, iucABCD and iutA, and repB gene, which was involved in plasmid replication, were detected in all ST11-KL64 strains. Evolutionary transmission analysis suggested that ST11 CRKP strains might have evolved from KL47 into KL64 and were accompanied by multiple outbreak events. This study poses an urgent need for enhancing infection control measures in the hospital, especially in the intensive care unit where the patients are at high-risk for acquiring CRKP-BSI. IMPORTANCE CRKP-BSI is demonstrated to cause high mortality. In this study, we demonstrated that ST11 CRKP strains might carry many virulent genes. Meanwhile, outbreak events occurred several times in the strains collected. Carbapenemase acquisition (mainly KPC-2 carbapenemase) was responsible for carbapenem resistance of all the 146 CRKP strains. As 2 predominant strains, all ST11-KL64 strains, but not ST11-KL47 strains, carried rmpA2, iucABCD, iutA, as well as a plasmid replication initiator (repB). Our study suggested that the occurrence of region-specific recombination events manifested by the acquisition of some virulence genes might contribute to serotype switching from ST11-KL47 to ST11-KL64. The accumulation of virulent genes in epidemic resistant strains poses a great challenge for the prevention and treatment of BSI caused by K. pneumoniae in high-risk patients.

Whole genome sequencing of OXA-232-producing wzi93-KL112-O1 carbapenem-resistant Klebsiella pneumoniae in human bloodstream infection co-harboring chromosomal ISEcp1-based blaCTX-M-15 and one rmpA2-associated virulence plasmid

Objectives

To characterize one OXA-232-producing wzi93-KL112-O1 carbapenem-resistant Klebsiella pneumoniae (CRKP) co-harboring chromosomal bla_CTX-M-15 and one rmpA2-associated virulence plasmid.

Methods

Minimum inhibitory concentrations (MICs) were measured via broth microdilution method. Conjugation, chemical transformation, string test and Galleria mellonella infection model experiments were also conducted. Whole-genome sequencing (WGS) was performed on the Illumina and Nanopore platforms. Antimicrobial resistance determinants were identified using ABRicate program with ResFinder database. Insertion sequences (ISs) were identified using ISfinder. Bacterial virulence factors were identified using virulence factor database (VFDB). Wzi, capsular polysaccharide (KL) and lipoolygosaccharide (OCL) were analyzed using Kleborate with Kaptive. Phylogenetic analysis of 109 ST15 K. pneumoniae strains was performed using core genome multilocus sequence typing (cgMLST) on the Ridom SeqSphere+ server. MLST, replicons type, SNP strategies and another cgMLST analysis for 45 OXA-232-producing K. pneumoniae strains were further conducted using BacWGSTdb server.

Results

K. pneumoniae KPTCM strain belongs to ST15 with wzi93, KL112 and O1. It possessed a multidrug-resistant (MDR) profile and was resistant to carbapenems (meropenem and ertapenem), ciprofloxacin and amikacin. Virulence assays demonstrated KPTCM strain possesses a low virulence phenotype. WGS revealed it contained one circular chromosome and nine plasmids. The carbapenemase-encoding gene bla_OXA-232 was located in a 6141-bp ColKP3-type non-conjugative plasmid and flanked by ΔISEcp1 and ΔlysR-ΔereA. Interestingly, bla_CTX-M-15 was located in the chromosome mediated by ISEcp1-based transposon Tn2012. Importantly, it harbored a rmpA2-associated pLVPK-like virulence plasmid with iutA-iucABCD gene cluster and one IS26-mediated MDR fusion plasmid according to 8-bp (AGCTGCAC or GGCCTTTG) target site duplications (TSD). Based on the cgMLST and SNP analysis, data showed OXA-232-producing ST15 K. pneumoniae isolates were mainly isolated from China and have evolved in recent years.

Conclusions

Early detection of CRKP strains carrying chromosomal bla_CTX-M-15, OXA-232 carbapenemase and pLVPK-like virulence plasmid is recommended to avoid the extensive spread of this high-risk clone.

Risk Factors for Mortality and Outcomes in Hematological Malignancy Patients with Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infections

Background

This study aimed to identify risk factors for mortality and outcomes in hematological malignancy (HM) patients with bloodstream infection (BSI) caused by carbapenem-resistant Klebsiella pneumoniae (CRKP).

Methods

A retrospective study was conducted at a tertiary teaching hospital in Henan Province, China, between January 2018 and December 2021. All BSIs caused by CRKP in hospitalized HM patients were identified. Data on patient demographics, disease, laboratory tests, treatment regimens, outcomes of infection, and the antimicrobial susceptibility of each isolate were collected from medical records.

Results

A total of 129 patients with CRKP BSI were included in the study, and the 28-day mortality rate was 80.6% (104/129). In Cox analysis an absolute neutrophil count < 500 at discharge (hazard ratio [HR] 6.386, 95% confidence interval [CI] 3.074–13.266, p < 0.001), intensive care unit admission (HR 1.834, 95% CI 1.065–3.157, p = 0.029), and higher Pitt bacteremia score (HR 1.185, 95% CI 1.118–1.255, p < 0.001) were independent risk factors associated with 28-day mortality. Survival curve analysis indicated that compared with ceftazidime-avibactam-based therapy, both polymyxin b (HR 8.175, 95% CI 1.099–60.804, p = 0.040) and tigecycline (HR 14.527, 95% CI 2.000–105.541, p =0.008) were associated with a higher risk of mortality.

Conclusion

In HM patients CRKP BSI resulted in high mortality. Intensive care unit admission, higher Pitt bacteremia score, and absolute neutrophil count < 500 at discharge were independently associated with higher mortality. Early initiation of new agents such as ceftazidime-avibactam may improve outcomes.

Clinical Outcomes and Microbiological Characteristics of Sequence Type 11 Klebsiella pneumoniae Infection

Background

Sequence type 11 (ST11) Klebsiella pneumoniae (Kp) is highly prevalent in China and is a typical sequence type among KPC-producing isolates. This study aimed to evaluate the clinical outcomes and microbiological features of ST11 Kp infections.

Methods

A retrospective cohort study was conducted at Peking University Third Hospital from January 2017 to March 2021. Clinical data were collected from medical records. Antimicrobial susceptibility testing and string tests were performed. Whole-genome sequencing was used to analyze the capsular serotypes, detect virulence-associated genes, and perform multilocus sequence typing. The risk of all-cause mortality in ST11 Kp-infected patients was compared to that in non-ST11 Kp-infected patients.

Results

From 139 patients infected with Kp, 49 ST11 Kp (35.3%) strains were isolated. The Charlson comorbidity index in the ST11 group was higher than that in the non-ST11 group (3.94 ± 1.59 vs. 2.41 ± 1.54, P = 0.001). A greater number of ST11 Kp-infected patients required ICU admission (46.9 vs. 16.7%, P < 0.001) and mechanical ventilation (28.6 vs. 10.0%, P = 0.005). All ST11 isolates presented a multidrug-resistant (MDR) phenotype, and twenty-nine (59.2%) hypervirulent Kp (hvKp) were identified. Twenty-four ST11 strains presented with hypermucoviscosity. The presence of capsular types K47 and K64 was frequent in the ST11 Kp strains (P < 0.001). The key virulence-associated genes rmpA, rmpA2, iucA, iroB, and peg344 were present in 26.5, 42.9, 59.2, 0, and 26.5% of the isolates, respectively, in the ST11 group. Twenty-one ST11 isolates harbored the combination of iucA+rmpA2. The 30-day mortality rate and sequential organ failure assessment (SOFA) score were significantly higher in ST11 Kp-infected patients than in non-ST11 Kp-infected patients (P < 0.01). ST11 Kp infection appeared to be an independent risk factor for mortality in ST11 Kp-infected patients.

Conclusions

A high prevalence of the ST11 clone was found in the hospital, which accounted for elevated antimicrobial resistance and exhibited great molecularly inferred virulence. Patients with ST11 Kp infection had a tendency toward increased 30-day mortality and SOFA scores. ST11 Kp infection was an independent risk factor for mortality, suggesting that enhanced surveillance and management are essential.

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.

Multicenter Genomic Analysis of Carbapenem-Resistant Klebsiella pneumoniae from Bacteremia in China

Klebsiella pneumoniae is one of the most common Gram-negative bacilli isolated from bloodstream infections worldwide, and recently an increased rate of carbapenem resistance has been reported in this pathogen. This study aims to describe the genomic characteristics of carbapenem-resistant K. pneumoniae (CRKP) isolated from patients with bacteremia in China. We analyzed 147 isolates from patients with bacteremia attended in 12 referral hospitals in China between April 2015 and November 2018. We conducted a phenotypic susceptibility evaluation and whole genome sequence analysis to characterize antimicrobial resistance profile, virulence genes, and dominant clones among CRKP. ST11 accounted for most infections (n = 98, 66.6%), followed by ST45 (n = 12, 8.2%), ST15 and ST290 (n = 8, 5.4% each). KPC (n = 98, 66.7%) and NDM (n = 27, 18.4%) are the main carbapenemases detected in the CRKP isolates. We detected yersiniabactin (n = 123, 83.7%) and aerobactin (49.9%) siderophores, and both rmpA and aerobactin genes in 21 ST11 isolates (21.43%), which are considered characteristic biomarkers of hypervirulent strains. Isolates showed high resistance rates to the β-lactams (>90%) and other antibiotics classes such as fluoroquinolones, aminoglycosides and tetracyclines (50%), but were susceptible to ceftazidime-avibactam (74.8%). In addition, we detected intra-hospital transmission of ST11 and ST45 strains in single and multiple wards in several hospitals, whereas inter-hospital transmission was relatively uncommon. In summary, we observed significantly genomic diversity of CRKP bacteremia isolates in China, although KPC-2 producing ST11 strains were found to be the most common clonal types. Reducing intra-hospital transmission remains to be the key to control CRKP caused bloodstream infections in China. IMPORTANCE K. pneumoniae is one of the most frequent Gram-negative bacilli isolated from bloodstream infections worldwide and recent studies have shown an increased rate of carbapenem resistance in China. Among carbapenem-resistant K. pneumoniae (CRKP) diverse clones have been reported, especially the high-risk clone ST11, which also exhibited a multidrug resistant phenotype. In addition to the antimicrobial resistance, previous studies have detected strains co-harboring virulent traits, highlighting the potential of transmission of both antimicrobial resistant and virulent strains. Here we studied the antimicrobial resistance profile, virulence genes and hospital transmission of CRKP from bacteremic patients in China. This study showed a high clonal diversity among CRKP, with the predominance of ST11 lineages. We detected virulence markers among multidrug resistant strains, and a high number of genetically similar isolates, suggesting intra-hospital transmission within single and multiple wards. Reducing intra-hospital transmission remains to be the key to control CRKP caused bacteremia in China.

Risk factors for infection and mortality caused by carbapenem-resistant Klebsiella pneumoniae: a large multicentre case-control and cohort study

OBJECTIVES

To elucidate the predictors of carbapenem-resistant Klebsiella pneumoniae (CRKP) infection and help clinicians better identify CRKP infection at an early age.

METHODS

We conducted a multicentre case-control study of 422 patients with CRKP infection and 948 with carbapenem-susceptible K. pneumoniae (CSKP) infection from March to July 2017. Binary logistic regression was used to identify risk factors for CRKP infection. The subgroups of CRKP respiratory infection, intra-abdominal infection, and bloodstream infection were also evaluated. Patients were followed up for 28 days. Independent risk factors for 28-day crude mortality of CRKP infection were analysed using Cox proportional hazards regression models.

RESULTS

Longer stay of hospitalization, stay in the ICU, previous exposure to antibacterial agents (especially carbapenems, quinolones, aminoglycosides, and tigecycline), invasive procedures, intravascular catheter use, tracheotomy, or admission to ICU in the preceding 90 days were risk factors for CRKP infection. Carbapenem exposure was the only common predictor of different types of CRKP infection. The 28-day mortality of CRKP infection was 13.1% and was independently associated with sex, admitted unit, and types of infection.

CONCLUSIONS

Strict policies for antibiotic use, cautious decisions regarding the implementation of invasive procedures, and careful management of patients with catheters, especially intravascular catheters, are necessary to handle CRKP infection.

Risk factors for and clinical outcomes of ceftazidime-avibactam-resistant carbapenem-resistant Klebsiella pneumoniae nosocomial infections: a single-center retrospective study

PURPOSE

The emergence of ceftazidime-avibactam (CZA) resistance in carbapenem-resistant Klebsiella pneumoniae (CRKP) has been increasingly reported in recent years. We aimed to identify the risk factors of CZA-resistant CRKP infection and assess clinical outcomes of the patients.

METHODS

The study retrospectively analyzed the clinical and microbiological data of patients with CRKP infection to identify risk factors, clinical features, and outcomes using multivariate logistic regression analysis.

RESULTS

A total of 103 patients with CRKP infection were enrolled in this study. Multivariate analysis showed previous renal replacement therapy (OR 3.966, 95% CI 1.301-12.090, P = 0.015) was an independent risk factor for CZA-resistant CRKP infection. The 28-day mortality was higher in patients infected with CZA-resistant CRKP (27.9%) than those with CZA-susceptible CRKP (7.1%) (P = 0.009). CZA-resistant CRKP infection (OR 20.308, 95% CI 1.461-282.293, P = 0.025), and mechanical ventilation (OR 14.950, 95% CI 1.034-216.212, P = 0.047) were independent predictors for 28-day mortality in patients with CRKP infection. Lower level of platelet count (OR 0.987, 95% CI 0.975-0.999, P = 0.032) on the day of CRKP infection onset was related to 28-day mortality. Kaplan-Meier curves showed that the CZA-resistant CRKP group had a shorter survival time than the CZA-susceptible CRKP group.

CONCLUSION

The prevalence and mortality of CZA-resistant CRKP are still increasing. Strengthening the hospital infection control of renal replacement therapy and mechanical ventilation may help to prevent CZA-resistant CRKP.

Risk Factors for a Hospital-Acquired Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infection: A Five-Year Retrospective Study

Purpose

This study aimed to describe trends in Klebsiella pneumoniae (KP) resistance in bloodstream infections (BSI) and to identify risk factors for a hospital-acquired carbapenem-resistant Klebsiella pneumoniae (CRKP) BSI and 28-day mortality from a hospital-acquired KP BSI.

Patients and Methods

We recorded the results of antimicrobial susceptibility testing of 396 KP-positive blood cultures from January 2016 to December 2020. A total of 277 patients with a KP BSI were included in this study, of which 171 had a hospital-acquired infection and 84 had a hospital-acquired CRKP BSI. Multivariate logistic regression analysis was used to identify risk factors for a hospital-acquired CRKP BSI and 28-day mortality from a hospital-acquired KP BSI.

Results

The proportion of hospital-acquired infections among KP BSI patients increased from 53.1% in 2016 to 72.8% in 2020. The detection rate of CRKP among KP BSI patients increased from 18.8% in 2016 to 37.7% in 2020. Multivariate logistic regression showed that β-lactam/β-lactamase inhibitor combinations (BLBLIs) exposure (P  = 0.022, OR 2.863), carbapenems exposure (P  = 0.007, OR 3.831) and solid organ transplantation (P   <0.001, OR 19.454) were independent risk factors for a hospital-acquired CRKP BSI. Risk factors for a 28-day mortality from hospital-acquired KP BSI were CRKP BSI (P  =0.009, OR 5.562), septic shock (P  =0.002, OR 4.862), mechanical ventilation>96 hours (P =0.020, OR 8.765), and platelet counts <100×10⁹/L (P  =0.003, OR 4.464).

Conclusion

The incidence of hospital-acquired KP BSI continues to rise and the proportion of CRKP BSI is also increasing. We believe that the use of the BLBLIs needs to be carefully evaluated in hospital-acquired infection. Hospital-acquired KP BSI Patients with CRKP BSI, septic shock, mechanical ventilation and deficiency of platelets are more likely to have a poor prognosis.

Blood bacterial resistant investigation collaborative system (BRICS) report: a national surveillance in China from 2014 to 2019

BACKGROUND

In this first national bloodstream infection (BSI) surveillance program in China, we assessed the composition of pathogenic bacteria and the trends for antimicrobial susceptibility over a 6-year period in China.

METHODS

Blood bacterial isolates from patients at hospitals participating in the Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected from January 2014 to December 2019. Only the first isolate of a species per patient was eligible over the full study period. Antibiotic-susceptibility testing was conducted by agar-dilution or broth-dilution methods as recommended by the Clinical and Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.

RESULTS

During the study period, 27,899 bacterial strains were collected. Gram-positive organisms accounted for 29.5% (8244) of the species identified and Gram-negative organisms accounted for 70.5% (19,655). The most-commonly isolated organisms in blood cultures were Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, coagulase-negative Staphylococci, and Acinetobacter baumannii. The prevalence of multidrug-resistant organisms, such as E. coli, K. pneumoniae, A. baumannii was higher in tertiary hospitals, whereas extended-spectrum, β-lactamase-producing E. coli (ESBL-E. coli), carbapenem-resistant A. baumannii were more prevalent in economically-developing areas. The prevalence of methicillin-resistant S. aureus declined from 39.0% (73/187) in 2014 to 25.9% (230/889) in 2019 (p < 0.05). The prevalence of ESBL-E. coli dropped from 61.2% (412/673) to 51.0% (1878/3,683) over time (p < 0.05), and carbapenem-resistant E. coli remained low prevalence (< 2%; 145/9944; p = 0.397). In contrast, carbapenem-resistant K. pneumoniae increased markedly from 7.0% (16/229) in 2014 to 19.6% (325/1,655) in 2019 (p < 0.05).

CONCLUSION

E. coli and K. pneumoniae were the leading causes of BSI during the 6-year study period. The major resistant pathogens declined or remained stable, whereas carbapenem-resistant K. pneumoniae continued to increase, which poses a great therapeutic challenge for BSIs.

Clonal Dissemination of Clinical Carbapenem-Resistant Klebsiella pneumoniae Isolates Carrying fosA3 and bla KPC-2 Coharboring Plasmids in Shandong, China

Treatment strategies of infection by carbapenem-resistant Klebsiella pneumoniae (CRKP) are limited. Fosfomycin, a broad-spectrum antibiotic, has attracted renewed interest in combination therapy to fight K. pneumoniae infections. However, reports on fosfomycin-resistant K. pneumoniae are increasing. Among the 57 CRKP strains, 40 (70.2%) were resistant to fosfomycin. Thus, whole-genome sequencing and bioinformatics analysis were conducted to reveal molecular characteristics of fosfomycin-resistant K. pneumoniae. Twenty-three isolates coharbored fosA^kp and fosA3, with K. pneumoniae carbapenemase (KPC)-producing ST11-KL64-wzi64-O2 (n = 13) and ST11-KL47-wzi209-OL101 (n = 8), the predominating clonal groups, while fosA3 was not detected in isolates carrying class B carbapenemase genes. Twenty-two (out of 26) ST11-KL64 strains were positive for rmpA2, of which 12 carried fosA3. Four of the 23 fosA3-positive isolates could successfully transfer their fosfomycin-resistant determinants to Escherichia coli J53Azi^R. All four strains belonged to ST11-KL47 with the same pulsed-field gel electrophoresis profile, and their transconjugants acquired fosfomycin, carbapenem, and aminoglycoside resistance. A 127-kb conjugative pCT-KPC-like hybrid plasmid (pJNKPN52_KPC_fosA) coharboring fosA3, bla_KPC–2, bla_CTX–M–65, bla_SHV–12, rmtB, and bla_TEM–1 was identified. ST11-KL64 and ST11-KL47 K. pneumoniae, with higher resistance and virulence, should be critically monitored to prevent the future dissemination of resistance.

Efficacy of Ceftazidime-Avibactam Versus Polymyxin B and Risk Factors Affecting Clinical Outcomes in Patients With Carbapenem-Resistant Klebsiella pneumoniae Infections a Retrospective Study

Background: The worldwide outbreak of carbapenem-resistant Klebsiella pneumoniae (CRKP) has become an urgent public health problem. High mortality and lack of effective treatments further pose new challenges to control this infection. However, studies about the evaluation of available antibiotics for CRKP infection are limited. The present study aimed to compare the efficacy of polymyxin B versus ceftazidime-avibactam (CAZ/AVI) in Chinese patients with CRKP infections and to identify risk factors affecting 7-day bacterial eradication and 28-day all-cause mortality. Methods: From January 8, 2018, to July 6, 2020, a total of 115 adult CRKP infected patients from two tertiary teaching hospitals in Shanghai, China were enrolled based on the inclusion and exclusion criteria. By reviewing electronic medical records of these patients, demographic and clinical data were extracted. The selected patients were divided into polymyxin B and CAZ/AVI groups according to primary antibiotic exposure to compare therapeutic effects. Binary logistic and cox's regression analysis were performed to identify risk factors for 7-day bacterial eradication and all-cause mortality. Results: One hundred and five patients were treated with polymyxin B (67.8%) or CAZ/AVI (32.2%). Patients in the CAZ/AVI group had significantly lower rates of 28-day mortality (8.1 vs 29.5%, p = 0.013), higher microbiological eradication and 28-day clinical success. Multivariate analysis showed that Charlson comorbidity index (≥3) and prior antibiotic use within 90 days were independent risk factors for poor microbiological eradication. Cox's regression analysis indicated that the length of hospitalization after CRKP infection and baseline creatinine clearance negatively affected 28-day mortality. Conclusion: CAZ/AVI was more effective than polymyxin B and appeared to be a promising drug for CRKP infection, especially for critically ill patients.

Assessment of Mortality-Related Risk Factors and Effective Antimicrobial Regimens for Treatment of Bloodstream Infections Caused by Carbapenem-Resistant Enterobacterales

Bloodstream infections (BSIs) attributable to carbapenem-resistant Enterobacterales (CRE-BSIs) are dangerous and a major cause of mortality in clinical settings. This study was therefore designed to define risk factors linked to 30-day mortality in CRE-BSI patients and to examine the relative efficacies of different antimicrobial treatment regimens in affected individuals. Data pertaining to 187 CRE-BSI cases from four teaching hospitals in China collected between January 2018 and December 2020 were retrospectively analyzed. For the 187 patients analyzed in this study, the 30-day mortality of CRE-BSI was 41.7% (78/187). Multivariate logistic regression analyses revealed that Pitt bacteremia score, immunocompromised status, meropenem MIC of ≥8 mg/liter,absence of source control of infection, and appropriate empirical therapy were independent predictors of CRE-BSI patient 30-day mortality. After controlling for potential confounding factors relative to ceftazidime-avibactam (CAZ-AVI) treatment, combination therapies including CAZ-AVI (odds ratio [OR], 1.287; 95% confidence interval [CI], 0.124 to 13.403; P = 0.833) were not related to any significant change in patient mortality risk, whereas the 30-day mortality risk was higher for patients administered other antimicrobial regimens (OR, 12.407; 95% CI, 1.684 to 31.430; P = 0.011). When patients were treated with antimicrobial regimens not containing CAZ-AVI, combination therapy (OR, 0.239; 95% CI, 0.077 to 0.741; P = 0.013) was related to a decreased 30-day mortality risk relative to monotherapy treatment. The mortality-related risk factors and relative antimicrobial regimen efficacy data demonstrated in this study may guide the management of CRE-BSI patients.

Risk Factors of 30-Day All-Cause Mortality in Patients with Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infection

An optimal antimicrobial regimen for the treatment of patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infection (BSI) is currently unavailable. This study aimed to identify the appropriate antibiotics and the risk factors of all-cause mortality for CRKP BSI patients. This retrospective cohort study included the hospitalized patients with CRKP BSI. Primary outcome was 30-day all-cause mortality. Cox regression analysis was used to evaluate the risk factors of 30-day mortality. A total of 89 patients were included with a 30-day mortality of 52.1%. A total of 52 (58.4%) patients were treated with appropriate antimicrobial regimens and 58 (65.2%) isolates carried bla_KPC-2 genes. Microbiologic eradication within 7 days (adjusted hazard ratio [HR] = 0.09, p < 0.001), platelet count (per 1 × 10⁴/mm³, adjusted HR = 0.95, p = 0.002), and Pitt bacteremia scores (adjusted HR = 1.40, p < 0.001) were independently associated with 30-day all-cause mortality. No effective antimicrobial regimens were identified. In conclusion, risk factors of 30-day mortality in patients with CRKP BSI included microbiologic eradication > 7 days, lower platelet count, and a higher Pitt bacteremia score. These findings render a new insight into the clinical landscape of CRKP BSI.

Pathogenesis of Gram-Negative Bacteremia

Gram-negative bacteremia is a devastating public health threat, with high mortality in vulnerable populations and significant costs to the global economy. Concerningly, rates of both Gram-negative bacteremia and antimicrobial resistance in the causative species are increasing. Gram-negative bacteremia develops in three phases. First, bacteria invade or colonize initial sites of infection. Second, bacteria overcome host barriers, such as immune responses, and disseminate from initial body sites to the bloodstream. Third, bacteria adapt to survive in the blood and blood-filtering organs. To develop new therapies, it is critical to define species-specific and multispecies fitness factors required for bacteremia in model systems that are relevant to human infection. A small subset of species is responsible for the majority of Gram-negative bacteremia cases, including Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii The few bacteremia fitness factors identified in these prominent Gram-negative species demonstrate shared and unique pathogenic mechanisms at each phase of bacteremia progression. Capsule production, adhesins, and metabolic flexibility are common mediators, whereas only some species utilize toxins. This review provides an overview of Gram-negative bacteremia, compares animal models for bacteremia, and discusses prevalent Gram-negative bacteremia species.

Shift in the Dominant Sequence Type of Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infection from ST11 to ST15 at a Medical Center in Northeast China, 2015-2020

Objective

To investigate the clinical characteristics and molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infection at a medical center in northeast China, especially after coronavirus disease (COVID-19) pandemic.

Methods

Fifty-one patients were diagnosed with CRKP bloodstream infection between January 2015 and December 2020, among which 42 isolates were available for further study. Species identification and antibiotic susceptibilities were tested with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and VITEK 2 systems. Carbapenemase genes, virulence genes and MLST genes were detected by polymerase chain reaction. Moreover, the string test and serum killing assay were performed to evaluate the virulence of the CRKP isolates.

Results

During the six-year period, the detection rate of CRKP in bloodstream infection showed an increasing trend, with the intensive care unit, hematology and respiratory medicine wards mainly affected. Molecular epidemiology analyses showed that KPC-2 was the dominant carbapenemase gene. In addition, the dominant sequence type (ST) of CRKP shifted from ST11 to ST15 strains, which were all sensitive to amikacin in contrast to the ST11 stains. Furthermore, ST15 CRKP strains were positive for the KfuB virulence gene and more resistant to serum killing compared to the ST11 CRKP strains. Nonetheless, the mortality rate of patients infected with ST11 and ST15 CRKP did not show any significant differences.

Conclusion

A shift in the dominant sequence type of CRKP bloodstream infections from ST11 to ST15 was observed during the years 2015–2020. Compared to ST11, the ST15 CRKP strains showed amikacin sensitivity, positivity for KfuB gene, and serum resistance, which may indicate stronger virulence.

Epidemiology, risk factors and outcomes of bloodstream infection caused by ESKAPEEc pathogens among hospitalized children

Background

Bloodstream infection (BSI) resulting from ESKAPEEc pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp) is relevant to high mortality and economic cost. Data concerning the impact of BSI due to ESKAPEEc in pediatric population was virtually scant. Our purpose was to summarize the epidemiology, risk factors and outcomes of ESKAPEEc BSI among hospitalized children.

Methods

Inpatients diagnosed with BSI with definite etiology between January 2016 and December 2018 were enrolled retrospectively at the West China Second University Hospital. Data were systematically reviewed on patients’ clinical characteristics and laboratory findings to ascertain independent predictors, clinical features and outcomes.

Results

Of the 228 patients with BSI, 174 (76.3%) were caused by ESKAPEEc (124 MDR-ESKAPEEc). Multivariate analysis demonstrated that premature and/ or low birth weight (odds ratio [OR] = 2.981, P = 0.036), previous surgery and/or trauma (OR = 5.71, P = 0.029) and source of urinary tract infection (OR = 10.60, P = 0.004) were independently associated with ESKAPEEc BSI. The independent risk factor for MRD-ESKAPEEc BSI was nosocomial infection (OR = 3.314, P = 0.037). The overall mortality rate in patients with ESKAPEEc BSI was 14.4% (25/174), and no significant difference was ascertained in mortality between MRD-ESKAPEEc and non-MRD ESKAPEEc BSI groups (13.7% vs. 11.4%, P = 0.692). In addition, previous surgery and/or trauma, thrombocytopenia, and mechanical ventilation were significant risk factors for mortality caused by ESKAPEEc BSI.

Conclusions

More than two-thirds of BSI among hospitalized children were caused by ESKAPEEc. Previous surgery and/or trauma, thrombocytopenia and mechanical ventilation increased the risk rate for mortality in ESKAPEEc BSI. The risk factors ascertained could assist physicians to early suspect ESKAPEEc BSI and MDR ESKAPEEc BSI.

Risk Factors for and Clinical Outcomes of Carbapenem-Resistant Klebsiella pneumoniae Nosocomial Infections: A Retrospective Study in a Tertiary Hospital in Beijing, China

Purpose

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections have been increasingly reported worldwide. We aimed to identify the risk factors for nosocomial CRKP infections and assess the clinical outcomes.

Patients and Methods

We conducted a case-control study with data collected from January 2016 to December 2018 in China. Controls were selected at a ratio of 1:1 from patients with nosocomial carbapenem-susceptible Klebsiella pneumonia (CSKP) infections. Risk factors for nosocomial CRKP infections and clinical outcomes were assessed with univariate and multivariate analyses.

Results

A total of one hundred forty-two patients with CRKP infections and one hundred forty-two patients with CSKP infections were enrolled in this study. Multivariate analysis showed that exposure to antibiotics within 3 months prior to admission (odds ratio OR, 2.585; 95% confidence interval [CI], 1.425–4.691; P=0.002), exposure to carbapenems (OR, 2.532; 95% CI, 1.376–4.660; P=0.003), exposure to fluoroquinolones (OR, 3.309; 95% CI, 1.326–8.257; P=0.010), and the presence of a nasogastric tube (OR, 2.796; 95% CI, 1.369–5.712; P=0.005) were independent risk factors for CRKP infections. The 30-day mortality rate in the CRKP group was 19.7%, while the in-hospital mortality rate was 28.9%. In the CRKP group, a higher creatinine level (OR, 1.009; 95% CI, 1.002–1.016; P = 0.013), being in shock at the time of a positive culture (OR, 4.454; 95% CI, 1.374–14.443; P = 0.013), and co-infection with other resistant bacteria (OR, 4.799; 95% CI, 1.229–18.740; P = 0.024) were independent predictors of in-hospital mortality in patients with CRKP infections. Kaplan–Meier curves showed that the CRKP group had a shorter survival time than the CSKP group.

Conclusion

Nosocomial CRKP infection was associated with exposure to carbapenems and fluoroquinolones within 3 months prior to hospitalization and the presence of a nasogastric tube. Patients infected with CRKP had higher 30-day and in-hospital mortality rates. A higher creatinine level, shock and co-infection with other resistant bacteria were independent predictors of in-hospital mortality in patients with CRKP infections.