Clinical characteristics and outcome of patients with community-onset Klebsiella pneumoniae bacteremia requiring intensive care

Current Positioning against Severe Infections Due to Klebsiella pneumoniae in Hospitalized Adults

Infections due to Klebsiella pneumoniae have been increasing in intensive care units (ICUs) in the last decade. Such infections pose a serious problem, especially when antimicrobial resistance is present. We created a task force of experts, including specialists in intensive care medicine, anaesthesia, microbiology and infectious diseases, selected on the basis of their varied experience in the field of nosocomial infections, who conducted a comprehensive review of the recently published literature on the management of carbapenemase-producing Enterobacterales (CPE) infections in the intensive care setting from 2012 to 2022 to summarize the best available treatment. The group established priorities regarding management, based on both the risk of developing infections caused by K. pneumoniae and the risk of poor outcome. Moreover, we reviewed and updated the most important clinical entities and the new antibiotic treatments recently developed. After analysis of the priorities outlined, this group of experts established a series of recommendations and designed a management algorithm.

Klebsiella pneumoniae Harboring Carbapenemase Genes in Taiwan: Its Evolution over 20 Years, 1998-2019

Klebsiella pneumoniae (K. pneumoniae) is an important pathogen causing various types of human infections in Taiwan. Carbapenemases have increasingly been reported in Enterobacterales in the past two decades. Carbapenemase-producing K. pneumoniae (CPKP), a major resistance concern that has emerged during the last decade, has become a global threat, with its related infections associated with high morbidity and mortality; however, therapeutic options for CPKP-associated infections are limited. Carbapenemases - including K. pneumoniae carbapenemases (KPC)-2, New Delhi metallo-β-lactamase (NDM)-1, Verona integron-encoded metallo-β-lactamase (VIM)-1, imipenemase (IMP)-1, and oxacillinase (OXA)-48 - have been reported worldwide, with a marked prevalence in different countries or areas of the world. Understanding the epidemiology of carbapenemase producers is important for the prevention of their expansion. This review examined the evolution of CPKP in the last two decades to better understand the role of CPKP in Taiwan. It discovered that the endemicity has changed from IMP-8, NDM-1 and VIM-1 to the most common KPC-2 and rapidly emerging OXA-48. Resistance epidemiology, genetic background, virulence factors, therapy, and outcomes are discussed in this paper.

iTRAQ-Based Proteomics Reveals Potential Anti-Virulence Targets for ESBL-Producing Klebsiella pneumoniae

Purpose

Treatment of infections with Klebsiella pneumoniae strains producing extended-spectrum beta-lactamases (ESBLs) is challenging due to the coexistence of multiple resistance mechanisms and the hypervirulent variant. Therefore, new targets or more effective treatment options aimed at ESBL-producing Klebsiella pneumoniae are urgently needed.

Materials and Methods

Here, we collected ESBL-producing and non-ESBL Klebsiella pneumoniae isolates and studied their differences from a proteomic point of view.

Results

We revealed treA, wza, gnd, rmlA, rmlC, rmlD, galE, aceE, and sucD as important virulence-related proteins in ESBL-producing Klebsiella pneumoniae, distinct from those in non-ESBL strains.

Conclusion

Our findings provide plausible anti-virulence targets and suggest new therapeutic avenues against ESBL-producing Klebsiella pneumoniae.

Dipeptidyl peptidase-4 inhibitor treatment could decrease Klebsiella pneumoniae pneumonia in patients with type 2 diabetes

OBJECTIVES

To investigate the effect of dipeptidyl peptidase-4 inhibitor (DPP4i) for Klebsiella pneumoniae (KP) pneumonia in patients with diabetes.

PATIENTS AND METHODS

Patients newly diagnosed with type 2 diabetes from 2009 to 2012 were recruited for this population-based and observational study. Diabetes complications severity index (DCSI) score and defined daily dose (DDD) were used for analysis. The multivariable Cox proportional hazards models were used to estimate the risk of KP pneumonia by DPP4i use, with adjustments for propensity score. The Kaplan-Meier method with the log-rank test was used to estimate the risk of KP pneumonia for DPP4i users.

RESULTS

34774 patients were included. The incidence rate of KP pneumonia in DDP4i users was 1.51 per 1000 person-years and that for the comparison was 2.25 per 1000 person-years. DDP4i users also had a significantly lower cumulative incidence of KP pneumonia (log-rank test p-value = 0.03). DDP4i users had a significantly lower risk of developing KP pneumonia compared with nonusers (adjusted HR = 0.67, 95% CI = 0.48-0.95).

CONCLUSIONS

For public health issue with type2 diabetes and infection, DPP4i use decreased KP pneumonia. Male gender, patients with co-morbidities, patients with higher DSCI score and higher DDD of DPP4i were observed to decrease KP pneumonia infection in our analysis. The possible role of DPP4i causing immunological disturbances should be considered.

Emerging antibiotics for community-acquired pneumonia

Introduction: Community-acquired pneumonia is the most common infection leading to hospitalization and death in all age groups, especially in elderly populations. Increasing antibiotic resistance among the common bacterial pathogens associated with community-acquired pneumonia, especially Streptococcus pneumoniae and staphylococci, has made its empirical treatment increasingly problematic, highlighting the need for effective antibiotic therapy.Areas covered: We searched PubMed and ClinicalTrials.gov for English-language reports of phase III clinical trials conducted between 2000 and 2019 concerning the antibiotic treatment of community-acquired pneumonia. We provide a summary of the latest approved drugs for this indication and highlight emerging drugs with a potential indication.Expert opinion: Ceftaroline (a new cephalosporine) and omadacycline (a cycline alternative), either parenterally or orally, are the only two new antibiotics to have been approved by the FDA for the treatment of community-acquired pneumonia in the last five years. Among the antimicrobials in development, Lefamulin (the first pleuromutilin), is currently in phase III development. Among the known antibiotic classes, solithromycin (a macrolide), nemonoxacin (a quinolone), and delafloxacin and zabofloxacin (both fluoroquinolones), have been studied in phase II and III in clinical trials. The availability of these new antibiotics may offer opportunities to improve the empirical treatment for community-acquired pneumonia.

Multidrug Resistant Gram-Negative Bacteria in Community-Acquired Pneumonia

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2019. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2019. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Multidrug Resistant Gram-Negative Bacteria in Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is associated with high morbidity and mortality worldwide [1]. Although several different bacteria and respiratory viruses can be responsible for CAP, Streptococcus pneumoniae (pneumococcus) remains the most common causative pathogen. A small proportion of CAP cases are caused by Gram-negative bacteria, especially Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii and Stenotrophomona maltophilia [2, 3]. The main problem concerning the treatment of Gram-negative bacterial infections is their related antibiotic resistance, reported as multidrug resistant (MDR = resistant to at least one agent in three or more groups of antibiotics), extensively drug resistant (XDR = resistant to at least one agent in all but two or fewer groups of antibiotics) and pan-drug resistant (PDR = resistant to all groups of antibiotics) [4]. This makes the clinical management of pneumonia caused by such pathogens a challenge for physicians. Taking into account the clinical severity that may be associated with CAP caused by Gram-negative bacteria (respiratory failure, bacteremia, shock, acute respiratory distress syndrome [ARDS]) the magnitude of the global health problem is tremendous.

Molecular Epidemiology of Klebsiella pneumoniae Strains Causing Bloodstream Infections in Adults

Molecular epidemiology of Klebsiella pneumoniae bacteremic strains allows for a better understanding of preventive and therapeutic strategies. Clinical and microbiological characteristics of 348 K. pneumoniae bacteremia cases (2007-2009) were retrospectively characterized by multilocus sequence typing and extended-spectrum beta-lactamases (ESBL) production. Overall, 223 (64.08%) cases were nosocomial (NA), 58 (16.67%) healthcare associated, and 67 (19.25%) community acquired. The main infection origins were urinary tract (16.6%, 50.0%, and 43.3%), biliary tract (10.8%, 24.2%, and 31.3%), and catheter-related infection (39.9%, 5.2%, and 0%). The 30-day mortality rate was around 20%. The rates of resistance were around 45% the highest being among NA cases, and ESBL production was detected in 7.2% of cases. A total of 161 different sequence types were grouped into 13 clonal sets by e-burst analysis. No relationship could be established between clonal sets and the origin of infection or the healthcare-related settings. The high genetic variability among the isolates suggests their intrapatient endogenous origin.

Clinical predictors and outcomes of Klebsiella pneumoniae bacteraemia in a regional hospital in Hong Kong

BACKGROUND

Klebsiella pneumoniae (KP) infection is associated with high morbidity and mortality. Multidrug resistance, especially extended-spectrum β-lactamase (ESBL) production, in KP is endemic worldwide.

AIM

To evaluate the clinical characteristics and outcomes of patients with KP bacteraemia in critical care and general ward settings.

METHODS

Adult patients admitted to a regional hospital in Hong Kong from January 1^st, 2009 to June 30^th, 2016 (7.5 years) with KP bacteraemia were included. Demographics, clinical features, microbiological characteristics, and outcomes were analysed.

FINDINGS

Among 853 patients, 178 (20.9%) required critical care and 176 (20.6%) died within 30 days of hospital admission. Thirty-day survivors were younger (P<0.001), had milder disease (defined by Sequential Organ Failure Assessment score) (P<0.001), presented with hepatobiliary sepsis (P<0.001) or urosepsis (P<0.001), less septic shock (P=0.013), fewer invasive organ supports (P<0.001), and had appropriate empirical antibiotics (P<0.001). Cox regression analysis showed that respiratory tract infection (hazard ratio: 2.99; 95% confidence interval: 2.061-4.337; P≤0.001), gastrointestinal tract infection (excluding hepatobiliary system) (2.763; 1.761-4.337; P≤0.001), mechanical ventilation (2.202; 1.506-3.221; P≤0.001), medical case (1.830; 1.253-2.672; P=0.002), inappropriate empirical antibiotics (1.716; 1.267-2.324; P≤0.001), female (1.699; 1.251-2.307; P<0.001), age >65 years (1.692; 1.160-2.467; P=0.006), and presence of solid tumour (1.457; 1.056-2.009; P=0.022) were independent risk factors for 30-day mortality. Unexpectedly, diabetes mellitus was associated with better 30-day survival (P=0.002). A total of 102 patients (12.0%) had infections with ESBL-producing strains, which were not associated with higher 30-day mortality.

CONCLUSION

KP bacteraemia is associated with high 30-day mortality. Site of infection, patients' comorbidities and appropriate use of empirical antibiotic are important predictors of patients' outcomes.

Klebsiella pneumoniae bloodstream infection, antimicrobial resistance and consumption trends in Ireland: 2008 to 2013

This study aimed to describe the epidemiology and antimicrobial resistance trends of Klebsiella pneumoniae bloodstream infection (BSI) in Ireland, in conjunction with national antimicrobial consumption data, during the period 2008 to 2013. A retrospective cohort study of K. pneumoniae BSI cases was conducted, based on notifications from Irish microbiology laboratories to the Health Protection Surveillance Centre (HPSC). In total, 1942 K. pneumoniae BSI cases were identified over 6 years, with 310 reported in 2008 and 326 reported in 2013. From 2008 to 2013, the proportion of isolates resistant to co-amoxiclav (24 % versus 29 %), piperacillin-tazobactam (11 % versus 27 %), third generation cephalosporins (3GC) (11 % versus 21 %), fluoroquinolones (13 % versus 21 %) and gentamicin (11 % versus 17 %) increased overall, concurrent with increasing national rates of antimicrobial consumption in Ireland (acute hospitals: 35.87 versus 39.77 defined daily doses (DDD) per 100 bed days used (BDU); and community: 6.38 versus 7.85 DDD per 1000 inhabitants per day (DID)). Enhanced data on the patient's admission route was available for 735 (38 %) cases. Overall, 51 % (n = 378) were categorised as 'acquired in the reporting hospital'. The all-cause mortality was 20 %, with 115 deaths, 101 (88 %) of whom died within 30 days of blood culture sampling date. K. pneumoniae is the second most common cause of Gram-negative BSI in Ireland, with most cases healthcare-associated and an all-cause mortality of 20 % reported in this study. Annual increases in resistance to different antimicrobial classes and in a multi-drug resistant phenotype have been observed, concurrent with increasing national broad spectrum antimicrobial consumption. These trends portend a risk to patient outcomes and highlight the urgency for individual prescribers to evaluate their antimicrobial prescribing habits in hospitals, long-term care and community settings.

Impacts of Hypervirulence Determinants on Clinical Features and Outcomes of Bacteremia Caused by Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae

We investigated the implications of hypervirulence determinants on clinical features of 48 adult patients with bacteremia caused by extended-spectrum β-lactamase-producing Klebsiella pneumoniae. Isolates in the hypervirulence group included any of the following virulence determinants: K1/K2 capsule serotypes, hypermucoviscosity phenotype, rmpA gene, or rmpA2 gene. Nonhypervirulence group isolates were negative for all of the above virulence factors. In this study, all isolates used were non-K1/K2 strains. Statistically significant differences were observed in clinical features of patients between the two groups. The hypervirulent isolates (n = 19), including 11 isolates with the hypermucoviscosity phenotype, 15 with the rmpA gene, and 16 with the rmpA2 gene, were more commonly recovered from diabetic patients and mainly manifested as secondary bacteremia (such as pneumonia, urinary tract infections, or other localized infections). The nonhypervirulent isolates (n = 29) were more commonly recovered from patients after prolonged hospital stays (>30 days) and mostly manifested as primary bacteremia. The overall in-hospital mortality was 56.3%. Hazard ratio (HR) analysis revealed the following positive predictors for mortality: nosocomial infection, stay in an intensive care unit, no removal of the central venous catheter, Charlson comorbidity score, and APACHE II score (≧15). The negative predictors were initial appropriate antibiotic therapy (HR 0.42) and urinary tract infection (HR 0.19). Charlson score was an independent confounder based on multivariate analysis (HR 1.43, 95% confidence interval 1.04-1.99). In conclusion, hypervirulence determinants played a role in causing secondary infections in diabetic patients; however, the presence of morbidity cofactors could themselves influence mortality, despite the absence of hypervirulence determinants.

Regulator of the mucoid phenotype A gene increases the virulent ability of extended-spectrum beta-lactamase-producing serotype non-K1/K2 Klebsiella pneumonia

BACKGROUND

To determine whether the presence of a capsule regulator gene [i.e., regulator of mucoid phenotype A (rmpA) gene] contributes to virulence on extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) with serotype non-K1/K2 strains.

METHODS

Twenty-eight ESBL-KP and non-ESBL-KP isolates were collected from the Tri-Service General Hospital (Taipei, Taiwan). The impact of the virulent rmpA gene in different capsular polysaccharide serotypes on ESBL-KP and non-ESBL-KP isolates was studied by a neutrophil phagocytosis reaction, a serum bactericidal assay, and an animal survival model.

RESULTS

Resistance to broad spectrum antibiotics was more prevalent in ESBL-KP strains than in non-ESBL-KP strains (p < 0.01). The ESBL-KP strains had different molecular patterns from non-ESBL-KP strains, based on pulsed-field gel electrophoresis. The frequency of serum-resistant isolates was the highest among ESBL-KP strains with rmpA (i.e., rmpA(+)) [71.4% (5/7)] than among of non-ESBL-KP rmpA(+) strains [42.8% (6/14)], ESBL-KP strains without rmpA (rmpA(-)) [33.3% (7/21)], and non-ESBL-KP rmpA(-) strains [14.2% (2/14)]. The most significant increase in neutrophil resistance occurred in the ESBL-KP rmpA(+) strains in comparison to the non-ESBL-KP rmpA(+), ESBL-KP rmpA(-), and non-ESBL-KP rmpA(-) strains (p < 0.01). The results of the animal survival model were compatible with the neutrophil phagocytosis reaction and serum bactericidal assay.

CONCLUSION

We conclude that the pathogenic potential is greater in rmpA(+) ESBL-KP strains than in rmpA(-) ESBL-KP and non-ESBL-KP strains.

Impact of revised susceptibility breakpoints on bacteremia of Klebsiella pneumoniae: Minimum inhibitory concentration of cefazolin and clinical outcomes

BACKGROUND

The Clinical and Laboratory Standards Institute (CLSI) revised the susceptibility breakpoints of cephalosporins for Enterobacteriaceae in 2010 and 2011. However, there is a lack of clinical data about the correlation of minimum inhibitory concentrations (MICs) and clinical outcome. Data for the distribution of MICs and clinical outcomes were analyzed in this study to evaluate the impact of changes in the CLSI breakpoints on the treatment of Klebsiella pneumoniae bacteremia.

METHODS

Ninety-seven bacteremic K. pneumoniae isolates from Taichung Veterans General Hospital, Taichung, Taiwan were collected for study during the period 2009-2011. The cefazolin MIC was determined by the broth microdilution method according to the recommendations of the CLSI. The MIC distribution of cefazolin and the clinical responses to definitive cefazolin treatment were analyzed.

RESULTS

The modal cefazolin MIC among the 97 isolates was 1 μg/mL and accounted for 73 (75.3%) isolates. There were 18 (18.6%) isolates with a cefazolin MIC of 2 μg/mL. The conventional dosage regimens of cefazolin (1 g every 6 hours or 8 hours) achieved a clinical cure in 70 (97.2%) of 72 patients in the group with a cefazolin MIC ≤1 μg/mL and in 14 (87.5%) of 16 patients in the group with a cefazolin MIC of 2 μg/mL. With the conventional dose, the cumulative clinical cure rate for K. pneumoniae bacteremia with cefazolin MIC ≤2 μg/mL was 95.5% (84/88 patients).

CONCLUSION

The conventional cefazolin dose still can result in satisfactory clinical cure rates for bacteremic episodes due to K. pneumoniae with cefazolin MIC ≤2 μg/mL, the revised susceptible breakpoint of CLSI 2011.

Clinical and microbiological characteristics of tigecycline non-susceptible Klebsiella pneumoniae bacteremia in Taiwan

Background

Resistance among Klebsiella pneumoniae to most antibiotics is on the rise. Tigecycline has been considered as one of the few therapeutic options available to treat multidrug-resistant bacteria. We investigated the clinical and microbiological characteristics of tigecycline non-susceptible K. pneumoniae bacteremia.

Methods

Adult patients with tigecycline non-susceptible K. pneumoniae bacteremia at a medical center in Taiwan over a 3-year period were enrolled. K. pneumoniae isolates were identified by the E-test using criteria set by the US Food and Drug Administration (FDA). Data on the clinical features of patients were collected from medical records. Genes for β-lactamases, antimicrobial susceptibilities and pulsed-field gel electrophoresis (PFGE) results were determined for all isolates.

Results

Of 36 patients, 27 had nosocomial bacteremia. Overall 28-day mortality was 38.9%. The MIC₅₀ and MIC₉₀ of tigecycline were 6 and 8 mg/L, respectively. No carbapenemase was detected among the 36 isolates. Twenty isolates carried extended spectrum β-lactamases and/or DHA-1 genes. No major cluster of isolates was found among the 36 isolates by PFGE. Intensive care unit onset of tigecycline non-susceptible Klebsiella pneumoniae bacteremia was the only independent risk factor for 28-day mortality.

Conclusions

The high mortality of patients with tigecycline non-susceptible K. pneumoniae bacteremia may suggest a critical problem. Further study to identify the possible risk factors for its development and further investigation of this type of bacteremia is necessary.