Risk Factors and Mortality of Elderly Patients with Hospital-Acquired Pneumonia of Carbapenem-Resistant Klebsiella pneumoniae Infection

Emergence of Tigecycline-Nonsusceptible Carbapenem-Resistant Klebsiella pneumoniae with Metallo-β-Lactamase and Transferable Ceftazidime-Avibactam Resistance in China

In recent years, resistance of Klebsiella pneumoniae to the clinical last-resort drugs carbapenem and tigecycline has intensified, including Metallo-β-Lactamase-producing K. pneumoniae (MBL-KP), which demonstrated resistance to ceftazidime-avibactam (CZA), posing a significant public health threat. This study focused on the carbapenems, CZA, and tigecycline resistance mechanisms of MBL-producing Carbapenem-resistant K. pneumoniae (MBL-CRKP). A retrospective study and genomic epidemiological analysis of Carbapenem-resistant K. pneumoniae (CRKP) strains isolated from Yangzhou City, Jiangsu Province, China, between 2016 and 2023 was conducted. The detection rate of CRKP in Yangzhou City has increased significantly in recent years, with five strains carrying the Metallo-β-Lactamases (MBLs) gene, all of which exhibited resistance to carbapenems and CZA. Two strains even showed reduced susceptibility to tigecycline, with one harboring tmexCD2-toprJ2. Moreover, three CRKP strains carrying both blaKPC-2 and blaNDM-1/blaNDM-29 genes were identified. Plasmids carrying MBL genes can horizontally transfer, leading to the spread of resistance, thus further exacerbating the difficulty of clinical treatment and the spread of resistance. In conclusion, this study not only revealed the resistance of MBL-CRKP strains to clinical last-resort therapeutic drugs but also explored the resistance mechanism and horizontal transfer through genomic analysis. Moreover, this study also suggested that microbial drug resistance surveillance should be conducted from the perspective of "one health" in the future to combat this global health challenge.

Analysis of clinical characteristics and mortality risk factors in patients with community-acquired pneumonia caused by Klebsiella pneumoniae

Community-acquired pneumonia (CAP) caused by Klebsiella pneumoniae (KP) results in high mortality. 121 cases were included in this study to explore the characteristics and risk factors of CAP patients caused by hypervirulent or resistant KP strains, which were limited reported in previous studies. We found that neither hypervirulent KP nor ESBL-producing KP infections affect mortality (P > 0.05), while increased qSOFA score (odds ratio [OR] 4.50, 95% confidence interval [CI] 1.55-12.76, P = 0.005) and APACHE-II score (OR 1.30, 95% CI 1.13-1.48, P < 0.001) were independent risk factors for mortality. In addition, the areas under the curve (AUCs) of qSOFA in predicting the mortality rate of all patients, ICU patients, and non-ICU patients were 0.82, 0.74, and 0.81, respectively. Elevated qSOFA or APACHE-II scores were considered independent risk factors for 28-day mortality. The qSOFA score was a good predictor of mortality among KP CAP patients.

Comparative analysis of clinical characteristics and outcomes between carbapenem-resistant and carbapenem-sensitive Klebsiella pneumoniae infections: insights from a tertiary hospital in Northern China

Background

To compare the risk factors, clinical outcomes, and mortality rates between carbapenem-resistant Klebsiella pneumoniae (CRKP) and carbapenem-sensitive Klebsiella pneumoniae (CSKP) infections.

Methods

A retrospective cohort study was conducted on patients with Klebsiella pneumoniae infections admitted to a tertiary hospital in Zhangjiakou, China. The research period is from January 2021 to December 2022. Data were analyzed using SPSS 24.0 and R. Univariate analysis identified potential risk factors for CRKP infections using appropriate statistical methods, followed by multivariable logistic regression to determine independent risk factors. Mortality rates between CRKP and CSKP groups were compared using chi-square tests, and survival curves were generated with the Kaplan-Meier method.

Results

The study included 283 patients, with 104 (36.7%) infected by CRKP and 179 (63.3%) by CSKP. CRKP patients had significantly higher body temperature, white blood cell counts, and inflammatory markers, while showing lower diastolic blood pressure and oxygen saturation (p < 0.05). CRKP infections were predominantly found in the ICU (49%) and mainly isolated from sputum (59%). Independent risk factors for CRKP included elevated C-reactive protein (OR = 1.02) and solid tumors (OR = 18.186). CRKP patients experienced longer hospital stays (25 days vs. 12 days for CSKP), longer ICU stays (13 days vs. 7 days), and higher 30-day mortality (23.1% vs. 17.9%, p = 0.012). The deceased group had elevated procalcitonin and creatinine levels, longer prothrombin time, and a greater need for mechanical ventilation compared to survivors (p < 0.05).

Conclusion

Patients with CRKP infections had higher mortality rates and longer hospital stays than those with CSKP infections. Previous hospitalization, hospitalization in an ICU, and mechanical ventilation were independent risk factors for CRKP infection.

Study on the predictive value of APACHE II score and neurogenic dysphagia in carbapenem-resistant Klebsiella pneumoniae

Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a growing challenge in clinical treatment globally. Early identification of high-risk patients is essential to control infection spread and improve treatment outcomes. This retrospective study analyzed 152 patients with K pneumoniae infections at the Second People's Hospital of Hefei City, Anhui Province, dividing them into carbapenem-resistant and non-carbapenem-resistant groups. Clinical data, microbiological test results, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, and neurogenic dysphagia status were evaluated to identify risk factors for CRKP infection. The study revealed that patients in the carbapenem-resistant group had significantly higher APACHE II scores and a higher incidence of neurogenic dysphagia (P < 0.05). Multivariate logistic regression analysis identified APACHE II scores and neurogenic dysphagia as independent risk factors for CRKP infection. Receiver operating characteristic curve analysis showed an area under the curve of 0.824 (95% confidence interval: 0.749-0.898) for the APACHE II score, with an optimal threshold of 14.5 points. A new predictive model combining neurogenic dysphagia with APACHE II scores improved classification performance, as demonstrated by Net Reclassification Improvement (NRI = 0.0967, 95% confidence interval: -0.0477 to 0.2410) and reclassification probability analysis, correctly reclassifying 24.32% of individuals into a higher risk category. The findings highlight the combined predictive value of APACHE II scores and neurogenic dysphagia for early identification and intervention in high-risk CRKP patients.

The prognostic value of neutrophil-to-lymphocyte ratio in adult carbapenem-resistant Klebsiella pneumoniae infection: a retrospective cohort study

Background

Systemic inflammatory indicators such as neutrophil-to-lymphocyte ratio (NLR) can effectively predict the prognosis of various inflammatory diseases. However, its prognostic effect on patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) infection is little known. The objective of this study was to investigate the risk factors for mortality associated with CRKP infection and the clinical value of NLR in predicting prognosis in these patients.

Methods

A total of 190 inpatients with CRKP infection from 1 January 2023 to 31 December 2023 were enrolled in this study, namely, 73 fatal cases and 117 survival cases in hospital. The medical data and examination results of these patients were collected. A logistic regression analysis was performed to assess the association between the NLR on the day of CRKP infection onset and all-cause mortality in hospital.

Results

The overall mortality rate of patients with CRKP infection was 38.42% (73/190). Of the 190 patients, 91 were co-infected with carbapenem-resistant Acinetobacter baumannii/carbapenem-resistant Pseudomonas aeruginosa (CRAB/CRPA). Multifactor regression analysis confirmed that carbapenem exposure in the past 14 days, central line insertion, and chronic Foley catheter requirement were independent risk factors for carbapenem-resistant bacteria co-infection. The multivariate analysis shows that admission to an ICU, co-infection with CRAB/CRPA, and higher NLR were independent risk factors for the mortality in hospital, while appropriate treatment within 3 days was an independent protective factor. The area under the curve (AUC) of the NLR was 0.696, and the cutoff value of the NLR was 10.73.

Conclusions

The NLR on the day of CRKP infection onset, admission to an ICU, and co-infection with CRAB/CRPA were identified as independent risk factors for all-cause mortality of patients with CRKP infection, while appropriate treatment within 3 days was recognized as an independent protective factor. The NLR serves as a conveniently accessible and independent prognostic biomarker for patients with CRKP infection.

Risk Factors and Outcomes of Community-Acquired Carbapenem-Resistant Klebsiella pneumoniae Infection in Elderly Patients

The increasing prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) infections is a global concern. Elderly patients have a diminished immune response and functional reserve, and are thus more vulnerable to bacterial infection. This study aimed to investigate the risk factors and outcomes in elderly patients with community-acquired CRKP infections. We performed a retrospective cohort study in a tertiary medical center between 1 January 2021, and 31 December 2021. All elderly patients who visited the emergency department during this period with culture-positive K. pneumoniae were enrolled, and their baseline demographics, laboratory profiles, management strategies, and outcomes were recorded and analyzed. We identified 528 elderly patients with K. pneumonia infection, and the proportion of patients with CRKP infection was 10.2% (54/528). Recent intensive care unit (ICU) admission and prior carbapenem use are independent risk factors for CRKP infection in elderly patients. Compared to patients with carbapenem-sensitive K. pneumoniae infection, those with CRKP infection had a significantly higher risk of adverse outcomes, including ICU care, respiratory failure, septic shock, and 90-day mortality. CRKP infection was also identified as an independent risk factor for 90-day mortality. Clinicians should be aware of the increasing prevalence of CRKP infections in elderly patients and judiciously choose appropriate antibiotics for these patients.

Clinical and Microbiological Risk Factors for 30-Day Mortality of Bloodstream Infections Caused by OXA-48-Producing Klebsiella pneumoniae

Bloodstream infections (BSI) caused by carbapenem-resistant Klebsiella pneumoniae are associated with high morbidity and mortality, and the therapy options available for their treatment are frequently scarce. The aim of this study was to analyze risk factors for 30-day mortality in patients with BSI caused by OXA-48-producing K. pneumoniae. The clinical and treatment features of the patients, who attended a single hospital over a five-year period, were retrospectively reviewed. The microbiological features, including the sequence types (ST) and the somatic (O) and capsular (K) antigens, as well as their resistance properties, comprising phenotypes and genetic background, were also considered. To identify the risk factors for 30-day mortality, uni- and multivariate statistical analyses were performed. The univariate analysis revealed statistically significant correlations for age, male gender, lower respiratory system infection, infection by ST147 isolates, and infection by isolates expressing the K64 antigen. The multivariate analysis, applied to variables yielding p-values close to or lower than 0.05 in the univariate analysis, confirmed gender, lower respiratory system infection, and infection with ST147 isolates, but not age or infection with K64 isolates, as risk factors for 30-day mortality. Moreover, the multivariate analysis showed that patients suffering from hematological malignancies or having been treated with inappropriate therapy, both having p-values slightly higher than 0.05 in the univariate analysis, exhibited significantly poorer outcomes in the multivariant analysis. The association of the ST147 clone with an increased risk of mortality is a novel finding that deserves further attention. Studies like the one presented here can certainly benefit the management of patients with nosocomial BSI caused by carbapenemase-producing K. pneumoniae.