Impact of Tigecycline's MIC in the Outcome of Critically Ill Patients with Carbapenemase-Producing Klebsiella pneumoniae Bacteraemia Treated with Tigecycline Monotherapy-Validation of 2019's EUCAST Proposed Breakpoint Changes

Clinical and Molecular Characteristics of Patients with Bloodstream Infections Caused by KPC and NDM Co-Producing Carbapenem-Resistant Klebsiella pneumoniae

Purpose

Klebsiella pneumoniae carbapenemase (KPC) and New Delhi metallo-β-lactamase (NDM) co-producing carbapenem-resistant Klebsiella pneumoniae (KPC-NDM-CRKP) isolates have been increasingly reported worldwide but have not yet been systematically studied. Thus, we have conducted a study to compare the risk factors, molecular characteristics, and mortality involved in clinical bloodstream infections (BSIs) caused by KPC-NDM-CRKP and KPC-CRKP strains.

Methods

A retrospective study was conducted on 231 patients with BSIs caused by CRKP at Jinling Hospital in China from January 2020 to December 2022. Antimicrobial susceptibility testing, carbapenemase genes detection and whole-genome sequencing were performed subsequently.

Results

Overall, 231 patients were included in this study: 25 patients with KPC-NDM-CRKP BSIs and 206 patients with KPC-CRKP BSIs. Multivariate analysis implicated ICU-acquired BSI, surgery within 30 days, and longer stay of hospitalization prior to CRKP isolation as independent risk factors for KPC-NDM-CRKP BSIs. The 30-day mortality rate of the KPC-NDM-CRKP BSIs group was 56% (14/25) compared with 32.5% (67/206) in the KPC-CRKP BSIs control group (P = 0.02). The ICU-acquired BSIs, APACHE II score at BSI onset, and BSIs caused by KPC-NDM-CRKP were independent predictors for 30-day mortality in patients with CRKP bacteremia. The most prevalent ST in KPC-NDM-CRKP isolates was ST11 (23/25, 92%), followed by ST15 (2/25, 8%).

Conclusion

In patients with CRKP BSIs, KPC-NDM-CRKP was associated with an excess of mortality. The likelihood that KPC-NDM-CRKP will become the next "superbug" highlights the significance of epidemiologic surveillance and clinical awareness of this pathogen.

Clinical Efficacy, Antibiotic Resistance Genes, Virulence Factors and Outcome of Hospital-Acquired Pneumonia Induced by Klebsiella pneumoniae Carbapenemase 2-Producing with Tigecycline Treatment in the ICU

Purpose

Tigecycline is an agent for carbapenemase-producing Klebsiella pneumonia (KPC-KP), given its penetration into lung tissues. Our study focused on the molecular and clinical efficacy of tigecycline for hospital-acquired pneumonia (HAP) in the ICU.

Patients and Methods

A retrospective cohort study of 52 adult KPC-KP HAP patients by searching hospital medical records from January 2018 to December 2020 was established to investigate the epidemiology of KPC-KP infections for tigecycline treatment and the associated clinical efficacy of tigecycline. The KPC-KP isolates underwent multilocus sequence typing. Molecular typing, antimicrobial resistance, and virulence profiling were also analyzed by whole-genome sequencing of KPC-KP.

Results

Among 52 patients with KPC-KP, the ICU mortality rate was 14/52 (27%), and there was no significant statistical difference in mortality between the effective group and failure group (p = 0.754). However, the duration of tigecycline was statistically different between the two groups of patients (14.4 vs 10 days, p=0.046). The total bacterial clearance rate was 6/52 (11.5%). There was no significant statistical difference in both groups (p=0.416). Antibiotic resistance genes (aac3iia) and virulence gene (AREO-iutA, Capsule-wzc) were negatively correlated with clinical efficacy (p = 0.011, OR = 1.237).

Conclusions

Bla_kpc was the main carbapenemase in all K. pneumoniae strains. ST11-KL64 KPC-KP was the most common virulence factors in KPC-KP isolates. This study suggested that antibiotic resistance genes (aac3iia) and virulence gene (AREO-iutA, Capsule-wzc) were independent mortality risk factors for patients with Klebsiella pneumoniae carbapenemase-2 producing K. pneumoniae infections, when during the tigecycline treatment. Molecular analysis of K. pneumoniae may provide an option when choosing the antimicrobial treatment.

Mortality of Pandrug-Resistant Klebsiella pneumoniae Bloodstream Infections in Critically Ill Patients: A Retrospective Cohort of 115 Episodes

BACKGROUND

The increased frequency of bacteraemias caused by pandrug-resistant Klebsiella pneumoniae (PDR-Kp) has significant implications. The aim of the present study was to identify predictors associated with mortality of PDR-Kp bacteraemias.

METHODS

Patients with monomicrobial bacteraemia due to PDR-Kp were included. K. pneumoniae was considered PDR if it showed resistance to all available groups of antibiotics. Primary outcome was 30-day mortality. Minimum inhibitory concentrations (MICs) of meropenem, tigecycline, fosfomycin, and ceftazidime/avibactam were determined by Etest, whereas for colistin, the broth microdilution method was applied. bla _KPC, bla _VIM, bla _NDM, and bla _OXA genes were detected by PCR.

RESULTS

Among 115 PDR-Kp bacteraemias, the majority of infections were primary bacteraemias (53; 46.1%), followed by catheter-related (35; 30.4%). All isolates were resistant to tested antimicrobials. bla _KPC was the most prevalent carbapenemase gene (98 isolates; 85.2%). Thirty-day mortality was 39.1%; among 51 patients with septic shock, 30-day mortality was 54.9%. Multivariate analysis identified the development of septic shock, Charlson comorbidity index, and bacteraemia other than primary or catheter-related as independent predictors of mortality, while a combination of at least three antimicrobials was identified as an independent predictor of survival.

CONCLUSIONS

Mortality of PDR-Kp bloodstream infections was high. Administration of at least three antimicrobials might be beneficial for infections in critically ill patients caused by such pathogens.