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

Clinical risk factors and outcomes of carbapenem-resistant Escherichia coli nosocomial infections in a Chinese teaching hospital: a retrospective study from 2013 to 2020

The emergence of carbapenem-resistant Escherichia coli strains poses a considerable challenge to global public health, and little is known about carbapenemase-producing E. coli strains in Tianjin, China. This study aimed to investigate the risk factors for infections with carbapenem-resistant E. coli (CREC) strains. This retrospective case-control study was conducted at a tertiary teaching hospital. A total of 134 CREC clinical isolates were collected from the General Hospital of Tianjin Medical University between 2013 and 2020. The control group was selected at a ratio of 1:1 from patients with nosocomial carbapenem-susceptible E. coli infection. Risk factors for nosocomial CREC infection and clinical outcomes were analyzed using univariate and multivariate analyses. Multivariate analysis revealed that cephalosporin exposure (odd ratio OR = 2.01), carbapenem exposure (OR = 1.96), glucocorticoid exposure (OR = 32.45), and surgical history (OR = 3.26) were independent risk factors for CREC infection. The in-hospital mortality rate in the CREC group was 29.1%, and age >65 years (OR = 3.19), carbapenem exposure (OR = 3.54), and central venous catheter insertion (OR = 4.19) were independent risk factors for in-hospital mortality in patients with CREC infections. Several factors were identified in the development of nosocomial CREC infections. The CREC isolates were resistant to most antibiotics. Reducing CREC mortality requires a comprehensive consideration of appropriate antibiotic use, underlying diseases, and invasive procedures.IMPORTANCEEscherichia coli is an opportunistic pathogen that causes severe hospital-acquired infections. The spread of carbapenem-resistant E. coli is a global threat to public health, and only a few antibiotics are effective against these infections. Consequently, these infections are usually associated with poor prognosis and high mortality. Therefore, understanding the risk factors associated with the causes and outcomes of these infections is crucial to reduce their incidence and initiate appropriate therapies. In our study, several factors were found to be involved in nosocomial carbapenem-resistant E. coli (CREC) infections, and CREC isolates were resistant to most antibiotics. Reducing CREC mortality needs a comprehensive consideration of whether antibiotics are used appropriately, underlying diseases, and invasive interventions. These findings provide valuable evidence for the development of anti-infective therapy, infection prevention, and control of CREC-positive infections.

Molecular Epidemiology of Carbapenem Resistant Klebsiella Pneumoniae in Northern China: Clinical Characteristics, Antimicrobial Resistance, Virulence and Geographic Distribution

Purpose

In this article, we studied in detail 74 Carbapenem Resistant Klebsiella pneumoniae (CRKP) in Shanxi to provide essential insight into development of effective strategies for control of CRKP.

Patients and Methods

From 2018 to 2021, we collected 74 clinical CRKP from 11 hospitals in Shanxi Province. Clinical data were obtained from medical records, and all isolates were subjected to antimicrobial susceptibility testing, multi locus sequence typing, capsular serotypes, resistant gene profiles and virulence gene profiles. The synergistic activity was performed by microdilution checkerboard method.

Results

Our study found differences in the clinical characteristics of CRKP between regions in Shanxi. Sequence type (ST) 11 was the dominant ST in Shanxi; however, the ST types in Shanxi had become more diverse over time and the proportion of STs showed a more balanced distribution with a significant decrease in ST11. NDM was the most common carbapenemase in Shanxi. In addition, the STs, carbapenemases, serotypes and virulence gene distribution varied by region in Shanxi. Moreover, tigecycline in combination with carbapenems and aztreonam had an excellent synergistic effect on CRKP in vitro.

Conclusion

The results of this study provide essential insight into development of effective strategies for control of CRKP in Shanxi.

Development of a nomogram for predicting nosocomial infections among patients after cardiac valve replacement surgery

AIMS AND OBJECTIVES

To construct a predictive nomogram of the risk of nosocomial infections among patients after cardiac valve replacement surgery.

BACKGROUND

Nosocomial infections are a standout challenge that worsens the prognosis of patients after valve replacement surgery. However, studies on the nomogram of nosocomial infections in these patients have remained scarce.

DESIGN

A retrospective cohort study.

METHODS

Patients (n = 720) following valve replacement surgery from 2018 to 2019 were selected. LASSO regression and multivariate logistic regression were utilised to ascertain predictors of nosocomial infections. The predictive performance of the nomogram was appraised by calibration and discrimination. Decision and impact curves were used to assess the clinical utility. Internal validation was implemented via 1000 bootstrap samples to mitigate overfitting. TRIPOD guidelines were used in this study.

RESULTS

One hundred and fifty one patients (20.97%) experienced nosocomial infections following valve replacement surgery. Heart failure, preoperative anaemia, valve material, American Society of Anesthesiologists score ≥ IV, prolonged duration of surgery, duration of mechanical ventilation ≥ 24 h and indwelling nasogastric tube were predictors of nosocomial infections. Using these variables, we developed a predictive nomogram of the occurrence of nosocomial infections and the internal validation results demonstrated good discrimination and calibration of the nomogram. The clinical decision and impact curve revealed significant clinical utility.

CONCLUSIONS

The present study constructed a nomogram for predicting the risk of nosocomial infections in patients following cardiac valve replacement surgery. This nomogram may strengthen the effective screening of patients at high risk of nosocomial infections.

RELEVANCE TO CLINICAL PRACTICE

This risk warning tool can assist clinical staff in making decisions and providing individualised infection control measures for patients, which has a significant reference value for clinical practice.

NO PATIENT OR PUBLIC CONTRIBUTION

The data for this study were obtained from the hospital database, and the entire process of the study did not involve patient participation.

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.

Phenotypic and Genetic Analysis of KPC-49, a KPC-2 Variant Conferring Resistance to Ceftazidime-Avibactam and Maintaining Resistance to Imipenem and Meropenem

Purpose

Klebsiella pneumoniae, a gram-negative bacterium, poses a severe hazard to public health, with many bacterial hosts having developed resistance to most antibiotics in clinical use. The goal of this study was to look into the development of resistance to both ceftazidime-avibactam and carbapenems, including imipenem and meropenem, in a K. pneumonia strain expressing a novel K. pneumoniae carbapenemase-2 (KPC-2) variant, referred to as KPC-49.

Methods

After 1 day of incubation of K1 on agar containing ceftazidime-avibactam (MIC = 16/4 mg/L), a second KPC-producing K. pneumoniae strain (K2) was recovered. Antimicrobial susceptibility assays, cloning assays, and whole genome sequencing were performed to analyse and evaluate antibiotic resistance phenotypes and genotypes.

Results

K. pneumoniae strain (K1), that produced KPC-2, was susceptible to ceftazidime-avibactam but resistant to carbapenems. The K2 isolate harboured a novel bla _KPC-49 variant, which differs from bla _KPC-2 by a single nucleotide (C487A), and results in an arginine-serine substitution at amino acid position 163 (R163S). The mutant K2 strain was resistant to both ceftazidime-avibactam and carbapenems. We demonstrated the ability of KPC-49 to hydrolyse carbapenems, which may be attributed to high KPC-49 expression or presence of an efflux pump and/or absence of membrane pore proteins in K2. Furthermore, bla_KPC-like was carried on an IncFII (pHN7A8)/IncR-type plasmid within a TnAs1-orf-orf-orf-orf-orf-orf-ISKpn6-bla _KPC-ISKpn27 structure. The bla _KPC-like gene was flanked by various insertion sequences and transposon elements, including the Tn3 family transposon, such as TnAs1, TnAs3, IS26, and IS481-ISKpn27.

Conclusion

New KPC variants are emerging owing to sustained exposure to antimicrobials and modifications in their amino acid sequences. We demonstrated the drug resistance mechanisms of the new mutant strains through experimental whole genome sequencing combined with bioinformatics analysis. Enhanced understanding of laboratory and clinical features of infections due to K. pneumoniae of the new KPC subtype is key to early and accurate anti-infective therapy.

Mortality-Related Risk Factors and Novel Antimicrobial Regimens for Carbapenem-Resistant Enterobacteriaceae Infections: A Systematic Review

OBJECTIVE

Carbapenem-resistant Enterobacteriaceae (CRE) has become a significant public health problem in the last decade. We aimed to explore the risk factors of mortality in patients with CRE infections and to focus on the current evidence on antimicrobial regimens for CRE infections, particularly from the perspective of mortality.

METHODS

A systematic literature review was performed by searching the databases of EMBASE, PubMed, and the Cochrane Library to identify studies that evaluated mortality-related risk factors and antimicrobial regimens for CRE infections published from 2012 to 2022.

RESULTS

In total, 33 and 28 studies were included to analyze risk factors and antibiotic treatment, respectively. The risk factors most frequently reported as significantly associated with CRE mortality were antibiotic use (92.9%; 26/28 studies), comorbidities (88.7%; 23/26 studies), and hospital-related factors (82.8%; 24/29 studies). In 10 studies that did not contain ceftazidime/avibactam (CAZ-AVI) therapy, seven demonstrated significantly lower mortality in combination therapy than in monotherapy. However, 5 of 6 studies identified no substantial difference between CAZ-AVI monotherapy and CAZ-AVI combination therapy. Six studies reported substantially lower mortality in CAZ-AVI regimens than in other regimens.

CONCLUSION

Several risk factors, particularly antibiotic use and patients' comorbidities, are strong risk factors for CRE mortality. The optimal regimen for CRE infections remains controversial. Combination therapy should be considered when carbapenems, colistin, tigecycline, or aminoglycosides are administered. CAZ-AVI appears to be a promising antibiotic for CRE infections. Most importantly, treatment should be individualized according to the source and severity of the disease or other highly related risk factors.

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.

The burden of carbapenem-resistant Enterobacterales infection in a large Thai tertiary care hospital

Background: Carbapenem-resistant Enterobacterales (CRE) are resistant to several other classes of antimicrobials, reducing treatment options and increasing mortality. We studied the clinical characteristics and burden of hospitalized adult patients with CRE infections in a setting where treatment options are limited.

Methods: A retrospective cohort study included adult inpatients between January 2015–December 2019 at Siriraj Hospital in Bangkok, Thailand. Clinical and microbiological data were reviewed.

Results: Of 420 patients with CRE infections, the mean age was 65.00 ± 18.89 years, 192 (45.72%) were male, and 112 (26.90%) were critically ill. Three hundred and eighty (90.48%) had Klebsiella pneumoniae, and 40 (9.52%) had Escherichia coli infections. The mean APACHE II score was 14.27 ± 6.36. Nearly half had previous hospitalizations (48.81%), 41.2% received antimicrobials, and 88.1% had undergone medical procedures before the onset of infection. The median time of onset of CRE infection was 16 days after admission. Common sites of infection were bacteremia (53.90%) and pneumonia (45.47%). Most CRE-infected patients had septic shock (63.10%) and Gram-negative co-infections (62.85%). Colistin (29.95%) and non-colistin (12.91%) monotherapies, and colistin-based (44.78%) and non-colistin-based (12.36%) combination therapies were the best available antimicrobial therapies (BAAT). The median length of hospitalization was 31 days, and the median hospitalization cost was US$10,435. The in-hospital mortality rate was 68.33%. Septic shock [adjusted odds ratio (aOR) 10.73, 5.65–20.42, p <0 .001], coinfection (aOR 2.43, 1.32–4.47, p = 0.004), mechanical ventilation (aOR 2.33, 1.24–4.36, p = 0.009), and a high SOFA score at onset (aOR 1.18, 1.07–1.30, p <0 .001) were associated with mortality.

Conclusion: CRE infection increases mortality, hospital stays, and healthcare costs. A colistin-based regimen was the BAAT in this study. Therefore, newer antimicrobial agents are urgently needed.

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.

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.