Infections Caused by Carbapenemase-Producing Klebsiella pneumoniae: Microbiological Characteristics and Risk Factors

Genomic and immunocyte characterisation of bloodstream infection caused by Klebsiella pneumoniae

OBJECTIVES

The aim of this study was to evaluate the characteristics of immunocyte associated with bloodstream infection (BSI) caused by Klebsiella pneumoniae (Kpn).

METHODS

Patients with BSI-Kpn were included from 2015 to 2022 in our hospital. Immunocyte subpopulations of enrolled BSI-Kpn patients were tested on the same day of blood culture using multicolor flow cytometry analysis. Antibiotic susceptibility test was determined by agar dilution or broth dilution method. All included isolates were subjected to whole genome sequencing and comparative genomics analysis. Clinical and genetic data were integrated to investigate the risk factors associated with clinical outcome.

RESULTS

There were 173 patients with non-duplicate BSI-Kpn, including 81 carbapenem-resistant Kpn (CRKP), 30 extended-spectrum β-lactamases producing Kpn (ESBL-Kpn), 62 none CRKP or ESBL-Kpn (S-Kpn). Among 68 ST11-CRKP isolates, ST11-O2v1:KL64 was the most common serotypes cluster (77.9%, 53/68), followed by ST11-OL101: KL47 (13.2%, 9/68). Compared with CSKP group, subpopulations of immunocyte in patients with CRKP were significantly lower (P < 0.01). In patients with ST11-O2v1:KL64 BSI-Kpn, the level of cytotoxic T lymphocytes (CD3 + CD8 +) is the highest, while the B lymphocytes (CD3-CD19 +) was the least. In addition, the level of immunocyte in patients with Kpn co-harbored clpV-ybtQ-qacE were lower than that in patients with Kpn harbored one of clpV, ybtQ or qacE and without these three genes. Furthermore, co-existence of clpV-ybtQ-qacE was independently associated with a higher risk for 30-day mortality.

CONCLUSIONS

The results demonstrate that patients with BSI-CRKP, especially for ST11-O2v1:KL64, exhibit lower leukomonocyte counts. In addition, BSI-Kpn co-harbored clpV-ybtQ-qacE is correlated to higher 30-day mortality.

[Carbapenemase Genes, Virulence Genes, and Molecular Epidemiology of Carbapenem-Resistant Klebsiella pneumoniae Derived From Bloodstream Infections]

Objective

To investigate the clinical characteristics and molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolated from patients with bloodstream infections in a large tertiary-care general hospital in Southwest China.

Methods

A total of 131 strains of non-repeating CRKP were collected from the blood cultures of patients who had bloodstream infections in 2015-2019. The strains were identified by VITEK-2, a fully automated microbial analyzer, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The minimum inhibitory concentration (MIC) was determined by microbroth dilution method. The common carbapenemase resistant genes and virulence factors were identified by PCR. Homology analysis was performed by multilocus sequencing typing. Whole genome sequencing was performed to analyze the genomic characteristics of CRKP without carbapenemase.

Results

The 131 strains of CRKP showed resistance to common antibiotics, except for polymyxin B (1.6% resistance rate) and tigacycline (8.0% resistance rate). A total of 105 (80.2%) CRKP strains carried the Klebsiella pneumoniae carbapenemase (KPC) resistance gene, 15 (11.4%) strains carried the New Delhi Metallo-β-lactamase (NDM) gene, and 4 (3.1%) isolates carried both KPC and NDM genes. Sequence typing (ST) 11 (74.0%) was the dominant sequence type. High detection rates for mrkD (96.2%), fimH (98.5%), entB (100%), and other virulence genes were reported. One hypervirulent CRKP strain was detected. The seven strains of CRKP that did not produce carbapenemase were shown to carry ESBL or AmpC genes and had anomalies in membrane porins OMPK35 and OMPK36, according to whole genome sequencing.

Conclusion

In a large-scale tertiary-care general hospital, CRKP mainly carries the KPC gene, has a high drug resistance rate to a variety of antibiotics, and possesses multiple virulence genes. Attention should be paid to CRKP strains with high virulence.

Analysis of risk factors associated with healthcare-associated carbapenem-resistant Klebsiella pneumoniae infection in a large general hospital: a case-case-control study

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection is a major public health threat in the world. To inform the prevention and control of CRKP infection in hospitals, this study analyzed the factors associated with CRKP infection and resistance to carbapenems in K. pneumoniae. This case-case-control study was carried out in a large general hospital in China from January 2016 to December 2018, comprising 494 hospitalized patients infected with CRKP (case group 1) and 2429 hospitalized patients infected with carbapenem-susceptible K. pneumoniae (CSKP, case group 2). We selected control groups from hospitalized patients without K. pneumoniae infections for the two case groups separately, with a 1:3 case-control ratio, to analyze the risk factors of the two case groups using the conditional logistic regression. Multivariate analysis showed that the risk factors of CRKP infection were intensive care unit (ICU) admission (odds ratio [OR], 6.85; 95% confidence interval [CI], 4.90-9.58; P < 0.001), respiratory failure (OR, 1.93; 95% CI, 1.34-2.77; P < 0.001), age-adjusted Charlson comorbidity index (aCCI; OR, 1.08; 95% CI, 1.02-1.15; P = 0.007), admission from the Emergency (OR, 1.37; 95% CI, 1.02-1.85; P = 0.036), and imipenem use (OR, 1.80; 95% CI, 1.30-2.49; P < 0.001). Among the aforementioned five risk factors, aCCI (OR, 1.09; 95% CI, 1.06-1.13; P < 0.001) was also identified as a risk factor of CSKP infections in multivariate analysis. The risk factors for resistance to carbapenems in K. pneumoniae were ICU admission, respiratory failure, admission from the Emergency, and imipenem use.

Klebsiella infections in a pediatric intensive care unit: incidence, antimicrobial susceptibility, and resistance genes

Background

Infections with multidrug-resistant K. pneumoniae is associated with high morbidity and mortality especially among critically ill patients. This was the main principle to conduct a detailed study about this organism, its resistance pattern, and type of its resistance genes

Subjects and methods

A cross-sectional study was carried out in a pediatric intensive care unit on patients with age range from 1 month to 12 years over a period of 1 year with positive K. pneumoniae using standard microbiological culture and antibiogram sensitivity testing. All collected samples were processed using multiplex PCR technique to identify the most relevant resistant genes.

Results

Forty-four patients had 54 positive cultures for K. pneumoniae, out of which 17 patients (38.6%) passed away. The most prevalent-resistant gene was New Delhi metallo-beta lactamase (NDM) gene (65.4%) followed by cefotaximase (CTX-M) gene (57.7%). Extensively drug-resistant K. pneumoniae was detected in (15.9%) of the results and was proved to be independent risk factor increasing mortality odds 139 folds.

Conclusion

The evolution of resistance of Klebsiella pneumoniae was proved to be associated with a high mortality rate. Continuous widespread surveillance of Klebsiella pathogen focusing on identification of resistance genes and antibiotic resistance pattern is highly recommended.

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.

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.

A Novel Nomogram for Predicting Risk Factors and Outcomes in Bloodstream Infections Caused by Klebsiella pneumoniae

Background

Our study aimed to explore the risk factors in bloodstream infections Klebsiella pneumoniae (BSI-KP) patients and establish nomograms to predict the probability of BSI-CRKP and the prognosis of BSI-KP.

Methods

A total of 252 BSI-KP patients were enrolled from a tertiary teaching hospital between January 1, 2015, and May 31, 2020. Risk factors associated with BSI-CRKP and factors associated with the 30-day mortality were identified using LASSO analysis, univariate and multivariate analysis.

Results

There were 121 (48.0%) patients with carbapenem-resistant K. pneumoniae (CRKP) and 131 (52.0%) patients with carbapenem-susceptible K. pneumoniae (CSKP). The multivariate logistic regression analysis demonstrated that gastric tube indwelling before BSI (OR=2.442, P=0.043) and more types of antibiotics use before BSI (OR=1.305, P=0.009) were independent risk factors for BSI-CRKP. And previous transplantations, prior ICU stay, gastric tube indwelling before BSI, more types of antibiotics use before BSI, lower Hb and cholinesterase were associated with CRKP-BSI. The C-index of models indicated its good accuracy (C-index 0.816, 95% CI 0.763–0.868). In patients with BSI-CRKP, further logistic regression analysis revealed urinary catheterization (OR=0.298, P=0.017) was found to be an independent risk factor for 30-day mortality, while ceftazidime/avibactam use (OR=8.438, P=0.003) was an independent favorable prognostic factor. The nomogram predicated CRKP, ICU hospitalization, more types of antibiotics use, tigecycline, PLT, urinary catheterization were associated with 30-day mortality in patients with BSI-KP. The discriminative ability of the predictive model, as assessed by C-index, was 0.813 (95% CI: 0.780–0.867).

Conclusion

Previous transplantations, prior ICU stay, gastric tube indwelling before BSI, more types of antibiotics use before BSI, lower Hb and cholinesterase represent significant risk factors for the development of BSI-CRKP. Our nomogram predicated thrombocytopenia was a sign for poor prognosis. Tigecycline resulted in higher mortality for patients with BSI-KP. Rational use of nomograms may help clinicians make better Clinical decisions when treating BSI-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.

High Prevalence and Fitness of IncFrepB Carrying qnrS1 in Hypervirulent Klebsiella pneumoniae Isolates

Objective: This study aimed to reveal the prevalence and fitness of qnrS1-carrying plasmids in hypervirulent Klebsiella pneumoniae (hvKP) isolates. Materials and Methods: Two hundred ninety-nine hvKP strains carrying qnrS1 were collected and screened for resistance genes using PCR and sequencing. The location of qnrS1 and rmpA2 was identified by Southern blotting. The transferability and fitness of qnrS1-carrying plasmids were analyzed by conjugation experiments and plasmid stability assay. Result: In 299 hvKP isolates, the most frequently detected capsular serotype was K64 (81.9%, 245/299), followed by K1 (4.7%, 14/299) and K2 (3.7%, 11/299). All K64-hvKP were sequence type (ST) 11. The qnrS1 and rmpA2 gene mainly was located on the ∼70-210 kb IncFrepB and ∼170-220 kb IncFIB plasmid, respectively. QnrS1-carrying plasmids could be transferred into Escherichia coli J53. However, the plasmid was transferred at a low rate of 13.4% (40/299). The 40 donor isolates belong to 4 STs-ST11, ST700, ST592, and ST86, and none contains the CRISPR-Cas loci. CRISPR-Cas loci were mainly found in ST23 K. pneumoniae. The relative fitness (RF) of qnrS1-carrying plasmids in ST86 and ST11 (cotransfer with bla_TEM-1 genes) was more than one and enhanced during cultivation, especially in ST86. However, the RF of qnrS1-carrying plasmids in ST592 and ST700 showed a high fitness cost. Whole-genome sequencing showed that the qnrS1-carrying plasmids in ST86 harbored more maintenance modules (SOS inhibitor protein psiB, parA, and parB partition systems) and insertion sequence (IS) elements (IS91, IS481-like, IS1380), indicating that the qnrS1-carrying plasmid in ST86 is more stable than the other types of qnrS1-carrying plasmids. Conclusion: QnrS1-carrying IncFrepB plasmids were highly prevalent and show polymorphism in hvKP strains. The qnrS1-carrying IncFrepB plasmid in ST86 hvKP should be highlighted due to its remarkable adaptability advantages.

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.

High Prevalence of Klebsiella pneumoniae Infections in AnHui Province: Clinical Characteristic and Antimicrobial Resistance

Background

Klebsiella pneumoniae (K. pneumoniae) causes community-acquired and hospital-acquired pneumonia. The mortality rates of invasive infections caused by hypervirulent K. pneumoniae (HvKP) are extremely high. However, the microbiological characteristics and clinical manifestations of K. pneumoniae in AnHui province still remain unclear.

Purpose

To show the high prevalence of HvKP infections regarding clinical characteristics and antimicrobial resistance in Anhui province.

Patients and Methods

A retrospective analysis was conducted to study the clinical data of 115 strains of K. pneumoniae from July 2019 to March 2020 in The First Affiliated Hospital of AnHui Medical University. The virulence genes, capsular types, carbapenemase genes, and molecular subtypes of these hypervirulent isolates were detected.

Results

Overall, 59.1% (68/115) cases were HvKP infections, mainly from the department of intensive care unit (ICU, n=14, 20.6%) and the department of respiratory and critical care (n=13, 19.1%). K2 was the most prevalent capsular serotype (n=26), followed by K1 (n=21). The results of MLST identification of 68 strains showed that ST23 (n=15, 22.1%) was the most common type of ST, followed by ST11 and ST65 (n=12, 17.6%), ST86 (n=9, 13.2%), and ST412 (n=6, 8.8%). Among 68 hvKP strains, 12 isolates were carbapenem resistant, and all except two harboured KPC.

Conclusion

The high incidence of carbapenemase producing HvKP in the Anhui province, especially the higher mortality of HvKP, should be paid more attention. Meanwhile, epidemiological surveillance and clinical treatment strategies should be continuously determined and implemented.

Drug Susceptibility and Molecular Epidemiology of Klebsiella pneumoniae Bloodstream Infection in ICU Patients in Shanghai, China

Background: Bloodstream infections (BSIs) are recognized as important nosocomial infections. Klebsiella pneumoniae is one of the major causes of bacteremia. This retrospective study focused on drug susceptibility and molecular epidemiology of K. pneumoniae isolated from intensive care unit (ICU) patients with BSI in Shanghai, China.

Methods: Consecutive K. pneumoniae isolates were collected from ICU patients. Antibiotic susceptibility testing was conducted by the broth microdilution method. PCR was performed to detect antimicrobial resistance genes. We also completed multilocus sequence typing (MLST) and GoeBURST was used to analyze the result of MLST.

Results: A total of 78 K. pneumoniae isolates were enrolled. K. pneumoniae from ICU-BSIs were highly resistant to almost all common antibiotics. The most frequent resistance determinants responsible for extended-spectrum β-lactamase (ESBL) producers were bla_CTX−M−14, bla_CTX−M−15, and bla_CTX−M−55. KPC was the only enzyme, which was detected by the carbapenemase producers. The most principal sequence types (STs) were ST11, ST15, and ST23.

Conclusion: This study presents for the first time the antibiotic resistance phenotype and molecular epidemiology of K. pneumoniae isolated from ICU patients with BSIs in Shanghai. ICU-BSI K. pneumoniae is characteristic of a high resistance rate. The occurrence of the KPC-2 enzyme may result from nosocomial clonal dissemination of ST11 K. pneumoniae.

Mortality-related factors in patients with OXA-48 carbapenemase-producing Klebsiella pneumoniae bacteremia

Carbapenemase-producing Enterobacterales constitute a serious public health threat; however, information on the oxacilinasa (OXA-48)-type is limited. The objective of the study was to evaluate the risk factors associated with 14-day mortality for patients with bacteremia due to OXA-48 carbapenemase-producing Klebsiella pneumoniae.We conducted a retrospective, single-center observational study of adult patients with K. pneumoniae bacteremia, classifying the strains as carbapenem-susceptible K. pneumoniae (CSKp) and carbapenem-resistant K. pneumoniae (CRKp). All of the CRKp strains were the OXA-48-type.The study included 202 cases of bacteremia: 114 due to CSKp and 88 due to CRKp. The clinical cure rate was higher for the patients with CSKp (85% vs 69% for CSKp and CRKp, respectively; P = .010), while the 14-day mortality rate was lower (13% vs 30%, P = .005). An INCREMENT-CPE score ≥7 (HR 3.05, 95% CI 1.50-6.25, P = .002) was the only independent factor associated with 14-day mortality for the patients with Klebsiella spp. bacteremia. Other factors related to 14-day mortality were a rapidly fatal prognosis (McCabe) (HR 7.1, 95% CI 2.75-18.37, P < .001), dementia (HR 5.9, 95% CI 2.0-7.43, P = .001), and a high-risk source of infection (HR 2.7, 95% CI 1.06-6.82, P = .038).The most important factors associated with 14-day mortality for the patients with K. pneumoniae bacteremia was an INCREMENT-CPE score ≥7, dementia, a McCabe score indicating a rapidly fatal prognosis and a high-risk source of infection. We found no relationship between a poorer outcome and CRKp isolation or inadequate antibiotic therapy.

A risk score based on pediatric sequential organ failure assessment predicts 90-day mortality in children with Klebsiella pneumoniae bloodstream infection

Background

Klebsiella pneumoniae bloodstream infection (Kp-BSI) is a serious threat to pediatric patients. The objective of this study was to explore the risk factors, validate the prediction efficiency of pediatric Sequential Organ Failure Assessment (SOFA) and establish better early predictors of mortality in pediatric patients with Kp-BSI.

Methods

All children diagnosed with Kp-BSI were included in this retrospective cohort study from January 2009 to June 2019. Basic characteristics, symptoms and physical examinations, treatments, laboratory statistics, and SOFA at the onset of Kp-BSI were recorded. The Cox proportional hazard model and receiver operating characteristic curves were used to assess the association between the variables and the 90-day mortality and their predictive value. DeLong’s test of receiver operating characteristic curves and integrated discrimination improvement index were used to determine the improvement in predictive capacity of the modified SOFA models. A predictive score was developed using multivariate logistic regression.

Results

Of the 146 children enrolled, 33 (22.6%) patients died within 90 days. Hospitalization in the last 6 months, intra-abdominal source of infection, presence of organ failure, and altered levels of blood biomarkers, including C-reactive protein, albumin, and lactate were significant risk factors for 90-day mortality. The area under the curve (AUC) of SOFA for predicting 90-day mortality was 0.80 (95% CI 0.71–0.89). Moreover, we found that a prediction model combining SOFA with two other parameters, namely hospitalization in the last 6 months and intra-abdominal source of infection, was better at predicting mortality (AUC = 0.89, 95% CI 0.82–0.96; sensitivity = 0.86; specificity = 0.84). According to this novel risk model, we defined three statistically different groups: low-risk, medium-risk and high-risk groups, with an observed 90-day mortality of 5.4, 35.7, and 72.0%, respectively. With reference to the low-risk patients, the medium-risk and high-risk groups had a higher mortality, with hazard ratios of 8.36 (95% CI 3.60–27.83) and 20.27 (95% CI 7.47–54.95), respectively.

Conclusions

The modified SOFA may be better than the original score to predict 90-day mortality in pediatric patients with Kp-BSI. Future prospective studies are required to validate this novel scoring system in external cohorts.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-020-05644-w.

Bloodstream Infections due to Carbapenem-Resistant Klebsiella pneumoniae: A Single-Center Retrospective Study on Risk Factors and Therapy Options

We aimed to compare efficacy of different patterns of antibiotics and explore the risk factors related to mortality in patients with bloodstream infections (BSIs) due to carbapenem-resistant Klebsiella pneumoniae (CRKP). This study retrospectively included 89 patients with BSIs due to CRKP with complete data during the year of 2018 in the First Affiliated Hospital of Zhejiang University School of Medicine. Overall, the 28-day mortality was 47.2% (42/89). Multivariate analysis of Cox regression revealed that hematological malignancy (hazard ratio [HR] 5.698; 95% confidence interval [CI], 2.405-13.504; p < 0.001) and Pitt bacteremia score (HR per unit increase, 1.303; 95% CI, 1.109-1.532; p = 0.001) were identified as independent predictors for 28-day mortality. Among 70 patients with appropriate therapy, 35 received tigecycline (TGC)-based therapy, 20 received polymyxin B (PMB)-based therapy, 9 received ceftazidime/avibactam-based therapy, and 6 patients had other kinds of antibiotics, including ciprofloxacin, amikacin, and cotrimoxazole. By adjusting variables selected by crude analysis, it showed that receiving PMB-based therapy provided a survival benefit comparing with TGC-based therapy (HR, 0.068; 95% CI, 0.018-0.260; p < 0.001). Hematological malignancy and Pitt bacteremia score were independent risk factors of death in patients with BSIs due to CRKP and PMB-based therapy improved survival rate compared with TGC-based therapy.

Successful control of the first carbapenem-resistant Klebsiella pneumoniae outbreak in a Chinese hospital 2017-2019

Background

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is considered as a serious global threat. CRKPs occurred only sporadically in the Second Hospital of Shanxi Medical University. Our study aimed to investigate and control the first outbreak of CRKP in our hospital occurred between October 2017 and August 2019.

Methods

The antimicrobial stewardship (AMS) workers have been implemented control measures properly. Clinical and epidemiological data were retrospectively collected from medical records. Carbapenemase genes were detected by modified carbapenem inactivation method (mCIM) test and the EDTA-modified carbapenem inactivation method (eCIM) test. Resistance genes were identified by polymerase chain reaction (PCR) and sequencing. Genetic relatedness was studied by multilocus sequence typing (MLST).

Results

During the outbreak, 31 patients were infected with CRKP isolates. 20 (64.5%) patients were infected with KPC-2 and/or NDM-1 producing K. pneumoniae. Mostly MLST-sequence types belonged to ST11 (21/31). The outbreak was two major K. pneumoniae clusters present in epidemiologically linked patients.

Conclusions

Setting up AMS workers is potentially a highly efficient strategy for the successful control of the outbreak. A multimodal and multidisciplinary infection control strategy proved to be crucial. The emergence of CRKP in our hospital emphasizes the importance of continuous monitoring of these isolates, which helps to limit the spread of CRKPs and improve the level of management.

Prediction of nosocomial infection incidence in the Department of Critical Care Medicine of Guizhou Province with a time series model

Background

The Department of Critical Care Medicine has the highest risk of nosocomial infection. This study used an autoregressive integrated moving average (ARIMA) model to simulate the prevalence of nosocomial infections in the Department of Critical Care Medicine of Guizhou Province. We also provided a policy basis for the prevention and control of hospital infection in the Department of Critical Care Medicine of Guizhou Province.

Methods

The data of ventilator-associated pneumonia, vascular catheter-related bloodstream infections, and urinary tract intubation-related urinary tract infections in nine tertiary A comprehensive treatment hospitals in Guizhou province from January 2014 to December 2019 were collected. The ARIMA time series model was used to evaluate the model fitting and prediction effects.

Results

After comparison, in the Department of Critical Care Medicine of Guizhou Province, the unsurpassed model of ventilator-associated pneumonia was the ARIMA (0,1,1) model, with a residual Ljuing-Box Q test result of Q=10.832 (P=0.865), suggesting it is a white noise sequence and its simulation and prediction effects are beneficial. The best model of vascular catheter-related bloodstream infection was the ARIMA (0,0,1) model, with a residual Ljuing-Box Q test result of Q=14.914 (P=0.602). These results suggest that it is a white noise sequence, and its simulation and prediction effects are sufficient. The optimal model of urinary tract intubation-related urinary tract infection is ARIMA (1,0,0), and the residual Ljuing-Box Q test result is Q=15.042 (P=0.592), suggesting it is a white noise sequence with an accurate simulation and prediction effect.

Conclusions

The ARIMA model can accurately simulate and predict nosocomial infection incidence rate in the Department of Critical Care Medicine of Guizhou Province, and can provide a reference for the prevention and control of nosocomial infections.

Risk factors for carbapenem-resistant Klebsiella pneumoniae infection relative to two types of control patients: a systematic review and meta-analysis

Background

Studies on risk factors for carbapenem-resistant Klebsiella pneumoniae (CRKP) infection have provided inconsistent results, partly due to the choice of the control group. We conducted a systematic review and meta-analysis to assess the risk factors for CRKP infection by comparing CRKP-infected patients with two types of controls: patients infected with carbapenem-susceptible Klebsiella pneumoniae (comparison 1) or patients not infected with CRKP (comparison 2).

Methods

Data on potentially relevant risk factors for CRKP infection were extracted from studies indexed in PubMed, EMBASE, Web of Science or EBSCO databases from January 1996 to April 2019, and meta-analyzed based on the outcomes for each type of comparison.

Results

The meta-analysis included 18 studies for comparison 1 and 14 studies for comparison 2. The following eight risk factors were common to both comparisons: admission to intensive care unit (ICU; odds ratio, OR_{comparison 1} = 3.20, OR_{comparison 2} = 4.44), central venous catheter use (2.62, 3.85), mechanical ventilation (2.70, 4.78), tracheostomy (2.11, 8.48), urinary catheter use (1.99, 0.27), prior use of antibiotic (6.07, 1.61), exposure to carbapenems (4.16, 3.84) and exposure to aminoglycosides (1.85, 1.80). Another 10 risk factors were unique to comparison 1: longer length of hospital stay (OR = 15.28); prior hospitalization (within the previous 6 months) (OR = 1.91); renal dysfunction (OR = 2.17); neurological disorders (OR = 1.52); nasogastric tube use (OR = 2.62); dialysis (OR = 3.56); and exposure to quinolones (OR = 2.11), fluoroquinolones (OR = 2.03), glycopeptides (OR = 3.70) and vancomycin (OR = 2.82).

Conclusions

Eighteen factors may increase the risk of carbapenem resistance in K. pneumoniae infection; eight factors may be associated with both K. pneumoniae infections in general and CRKP in particular. The eight shared factors are likely to be ‘true’ risk factors for CRKP infection. Evaluation of risk factors in different situations may be helpful for empirical treatment and prevention of CRKP infections.