Nosocomial Klebsiella pneumoniae bacteraemia in adult cancer patients—characteristics of neutropenic and non-neutropenic patients

Clinical Profiles, Laboratory Biomarkers, and Mortality in Cancer Patients with Lower Respiratory Tract Infections: A Prospective Cohort Study

Respiratory tract infections (RTIs) pose a substantial health burden worldwide, especially among immunocompromised groups like cancer patients. The aim of this prospective cohort study was to explore lower respiratory tract infections in cancer patients. We followed 107 cases with clinically or radiologically suspected lower respiratory tract infections until discharge or death, comprising 65 males and 42 females across diverse age groups. Clinical evaluations, including patient history, examination, and malignancy diagnosis, were conducted. Nasopharyngeal swabs (NPSs), sputum samples, and blood samples were collected within 24 h of symptom onset. Multiplex Real-Time PCR allowed for the simultaneous detection of viral, bacterial, and fungal infections, while conventional microbiological culture methods were used for bacterial and fungal analysis. SARS-CoV-2 infection was excluded in all of the enrolled patients using real-time RT-PCR. Hematological and biochemical analyses included hemoglobin, lymphocyte, neutrophil, and platelet counts, along with ALT, AST, creatinine, and CRP levels. Significant differences were noted in clinical presentations, management outcomes, and prognostic markers among patients with different hematological malignancies. Distinct clinical profiles were identified for leukemia, lymphoma, and solid tumors, with variations in age distribution and symptom prevalence. ICU admission rates varied significantly, with solid tumor patients exhibiting higher rates. The hematological and biochemical biomarkers differed across malignancies, with notable associations between lymphopenia, thrombocytopenia, and mortality following respiratory episodes. This study highlights the critical role of rapid pathogen detection and infection control measures in safeguarding vulnerable cancer patients from nosocomial transmission.

Deoxycholic Acid and Lithocholic Acid Alleviate Liver Injury and Inflammation in Mice with Klebsiella pneumoniae-Induced Liver Abscess and Bacteremia

Purpose

Klebsiella pneumoniae-induced liver abscess and baiacterem is a serious infectious disease with high mortality. Secondary bile acids (SBAs) are produced by intestinal flora through the metabolism of primary bile acids and play a role in promoting or inhibiting inflammation in some diseases. However, the immunomodulatory role of SBAs in bacterial infections of the liver remains unclear. This study aimed to investigate the anti-inflammatory and liver-protective effects of SBAs in K. pneumoniae-infected mice.

Methods

The absolute concentrations of deoxycholic acid (DCA) and lithocholic acid (LCA) in feces and serum were analyzed, and intestinal flora alterations between K. pneumoniae-infected and healthy control mice were examined. The effect of SBAs was investigated by analyzing the survival, tissue bacterial load, histopathology, and inflammatory factor levels in SBA-treated mice. The expression of crucial proteins implicated in the NF-κB pathway, as well as the G-protein-coupled bile acid receptor TGR5, was detected.

Results

The content of SBAs in feces and serum of the K. pneumoniae-infected group was significantly reduced, and significant changes in the composition of the intestinal flora were detected. The intestinal flora are directly related to the synthesis of SBAs. Ruminococcaceae levels in K. pneumoniae-infected mice were significantly lower than in healthy control mice. Oral administration of SBAs improved the survival and liver pathology of K. pneumoniae-infected mice, and reduced the bacterial load and the level of inflammatory factors. SBAs down-regulated the expression of key proteins in the NF-κB inflammatory signaling pathway, including the phosphorylation of IκBα and NF-κB p50 and the nuclear translocation of NF-κB p65. The protective effect of SBAs may be dependent on high TGR5 expression.

Conclusion

SBAs downregulate the NF-κB inflammatory signaling pathway through TGR5, protecting the liver and inhibiting inflammation in K. pneumoniae-induced liver abscess and bacteremia.

Characteristics and Clinical Outcomes of Extended-Spectrum beta-lactamase-producing Klebsiella pneumoniae Bacteremia in Cancer Patients

Background

Cancer patients can be at a higher risk of infection due to drug-resistant bacteria than the general population for various reasons. We performed a retrospective study to evaluate possible risk factors and outcomes of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) bacteremia in cancer patients.

Materials and Methods

Cases were divided into two groups based on whether or not the isolated strain produced ESBL and multivariable regressions were done to identify possible risk factors of ESBL-KP bacteremia and mortality. For ESBL-producing strain, additional molecular analysis was done.

Results

278 cases with KP bacteremia were identified between 2010 and 2012, of which ESBL-producers were 50 (18%). The presence of percutaneous drainage catheter [odds ratio (OR) 4.99, P <0.001] and prior exposure to certain classes of antibiotics including third-generation cephalosporin (OR 2.14, P = 0.03) had significant associations with ESBL-KP bacteremia. Individuals who died within 14 days after the onset of KP bacteremia were more likely to have higher mean Pitt bacteremia score (1.56 in survival group vs. 3.43 in mortality group, P <0.001), hemodialysis (OR 17.03, P = 0.01) and chronic liver disease (OR 5.57, P = 0.01). Although 14-day mortality was higher with ESBL production (OR 2.76, P = 0.04), no significant differences in 30-day mortality (OR 1.67, P = 0.20) and other morbidity indices were observed. 49 ESBL-KP isolates, 65.4% of them produced CTX-M-14 and CTX-M-15 enzymes, and ST711 was the most common.

Conclusion

There were several differences in clinical characteristics between ESBL-KP and non-ESBL-KP bacteremia in cancer patients, similar to previous reports including non-cancer patients.

Antimicrobial resistance trends in bloodstream infections at a large teaching hospital in China: a 20-year surveillance study (1998-2017)

Background

Bacterial bloodstream infections (BSIs) cause high morbidity and mortality worldwide in humans, but the pathogenic spectrum varies from region to region. Long-term monitoring of the pathogenic spectrum and changes in bacterial antibiotic resistance is hugely important for effective clinical therapy and infection control. This study examined the data for BSIs in Tongji Hospital, one of the largest teaching hospitals in China, in an attempt to gain better understanding of bacterial antibiotic resistance in China, focusing on central China.

Methods

Data from Tongji Hospital for a 20-year period (1998–2017) were used for a retrospective analysis to understand the pathogenic spectrum of BSIs and the changes occurring in antimicrobial resistance in central China. The disk diffusion and E test methods were used for antimicrobial susceptibility testing according to Clinical & Laboratory Standards Institute methodologies, and the data were analyzed by WHONET 5.6 software.

Results

The isolated pathogens mainly came from hospitalized patients not treated in intensive care units (ICUs), and accounted for 81.5% of the total (9130/11200). The most common Gram-negative and Gram-positive bacterial BSI-causing pathogens were Escherichia coli and Staphylococcus aureus, respectively. The detection rate for methicillin-resistant S. aureus (MRSA) in the hospitalized non-ICU patients increased from 8.4% in 1998–2002 to 63% in 2013–2017, while the detection rate for carbapenem-resistant (CR) Klebsiella pneumoniae was below 5% in 1998–2012 but increased to 34.9% in 2013–2017. In contrast, worryingly, the detection rate for CR K. pneumoniae in ICU patients increased from 0% in 2013 to 75% in 2016. E. coli displayed the highest sensitivity rates to imipenem, meropenem and amikacin, all of which were > 90%, followed by cefoxitin at > 80%, and cefoperazone/sulbactam at > 70%. K. pneumoniae isolates were most sensitive to imipenem, meropenem and amikacin antibiotics, with sensitivity rates exceeding 60%. S. aureus isolates were most sensitive to vancomycin, teicoplanin and trimethoprim/sulfamethoxazole, with sensitivity rates exceeding 90%.

Conclusions

BSIs caused by CR K. pneumoniae clearly posed a severe challenge to infection control and treatment of ICU and non-ICU patients in this retrospective study, while MRSA was an issue for non-ICU patients.

Antimicrobial resistance of pathogens causing nosocomial bloodstream infection in Hubei Province, China, from 2014 to 2016: a multicenter retrospective study

BACKGROUND

Data on the pathogens responsible for nosocomial bloodstream infection (BSI) and their antimicrobial resistance (AMR) in Hubei province are limited. This study was conducted to determine the major pathogens causing BSI and to characterize their AMR.

METHODS

Data from the China Antimicrobial Resistance Surveillance System (CARSS) from 2014 to 2016 were analyzed retrospectively.

RESULTS

Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae were the most common pathogens responsible for nosocomial BSI. Individuals aged 0-5 years and ≥ 40 years old were the major demographics at risk of infection by E. coli, K. pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii and Enterobacter cloacae, while individuals aged 0-5 years were the major demographic at risk of infection by S. aureus, Enterococcus faecalis, E. faecium, Streptococcus pneumoniae and Stenotrophomonas maltophilia. The frequencies of E. coli and K. pneumoniae isolates resistant to cefotaxime were 59.1% and 24.3%, respectively, and the frequencies of resistant isolates to ceftazidime were 42.9% and 27.2%, respectively. From 2014 to 2016, the frequency of extended-spectrum β-lactamase (ESBL)-positive E. coli declined from 29.07 to 24.5%, and the frequency of ESBL-positive K. pneumoniae declined from 18.64 to 12.33%. The frequency of carbapenem-resistant (CR) E. coli was below 0.5%, but 1-10% of K. pneumoniae isolates were CR.

CONCLUSIONS

The emergence of methicillin-resistant S. aureus and the expansion of ESBL and fluoroquinolone resistance among Gram-negative Enterobacteriaceae increased AMR severity. Carbapenemase-producing K. pneumoniae isolates responsible for nosocomial BSI increased year over year and effective infection control measures should be taken to prevent them from spreading.

Risk factors for Pseudomonas aeruginosa infections in Asia-Pacific and consequences of inappropriate initial antimicrobial therapy: A systematic literature review and meta-analysis

OBJECTIVES

Treating infections of Gram-negative pathogens, in particular Pseudomonas aeruginosa, is a challenge for clinicians in the Asia-Pacific region owing to inherent and acquired antimicrobial resistance. This systematic review and meta-analysis provides updated information on risk factors for P. aeruginosa infection in Asia-Pacific as well as the consequences (e.g. mortality, costs) of initial inappropriate antimicrobial therapy (IIAT).

METHODS

Embase and MEDLINE databases were searched for Asia-Pacific studies reporting the consequences of IIAT versus initial appropriate antimicrobial therapy (IAAT) in Gram-negative bacterial infections as well as risk factors for serious P. aeruginosa infection. A meta-analysis of unadjusted mortality was performed using a random-effects model.

RESULTS

A total of 22 studies reporting mortality and 13 reporting risk factors were identified. The meta-analysis demonstrated that mortality was significantly lower in patients receiving IAAT versus IIAT, with a 67% reduction observed for 28- or 30-day all-cause mortality (odds ratio=0.33, 95% confidence interval 0.20-0.55; P<0.001). Risk factors for serious P. aeruginosa infection include previous exposure to antimicrobials, mechanical ventilation and previous hospitalisation.

CONCLUSION

High rates of antimicrobial resistance in Asia-Pacific as well as the increased mortality associated with IIAT and the presence of risk factors for serious infection highlight the importance of access to newer and appropriate antimicrobials.

Epidemiology and management of healthcare-associated bloodstream infections in non-neutropenic immunosuppressed patients: a review of the literature

Advancements in medicine have led to a considerable increase in the proportion of patients living with severe chronic diseases, malignancies, and HIV infections. Most of these conditions are associated with acquired immune-deficient states and treatment-related immunosuppression. Although infections as a result of neutropenia have long been recognized and strategies for management were developed, non-neutropenic immunosuppression has been overlooked. Recently, community-acquired infections in patients with frequent, significant exposure to healthcare settings and procedures have been classified as 'healthcare-associated infections' since they are more similar to hospital-acquired infections. Most of the non-neutropenic immunosuppressed patients have frequent contact with the healthcare system due to their chronic and severe diseases. In this review, we focus on the healthcare-associated bloodstream infections in the most common non-neutropenic immunosuppressive states and provide an update of the recent evidence for the management of these infections.

Risk factors of mortality in bloodstream infections caused by Klebsiella pneumonia: A single-center retrospective study in China

The prevalence of Klebsiella pneumonia bloodstream infections (KP-BSIs) is increasing worldwide. Few study reports focus on the KP-BSIs published in Mainland China over the previous years. This study aimed to describe the risk factors of mortality from KP-BSIs.A retrospective study was conducted in a teaching hospital in Shanghai, China, for a period of 4 years. Risk factors related to the patient mortality were analyzed using the binary logistic regression model.Of 104 patients with KP-BSIs, the overall 30-day mortality rate was 25%. The logistic regression analysis revealed that thrombocytopenia (TB) (odds ratio [OR]: 1.007, 95% confidence interval [CI]: 1.002-1.013), pancreaticobiliary tract (PBT) (OR: 4.059, 95% CI: 1.398-11.78), and intra-abdominal infection (OR: 6.816, 95% CI: 1.806-25.716) were powerful risk factors leading to the mortality associated with KP-BSIs. Although prior antibiotic exposure, inappropriate empirical antibiotics, and inappropriate definitive antibiotics were not associated with mortality, multidrug-resistant (MDR) of KP-BSIs in the present study was high in both survivors and nonsurvivors (67.9% and 88.5%, respectively).TB, PBT, and intra-abdominal infection caused significant mortality rates increase in KP-BSIs during the study period.

Appropriate initial antibiotic therapy in hospitalized patients with gram-negative infections: systematic review and meta-analysis

Background

The rapid global spread of multi-resistant bacteria and loss of antibiotic effectiveness increases the risk of initial inappropriate antibiotic therapy (IAT) and poses a serious threat to patient safety. We conducted a systematic review and meta-analysis of published studies to summarize the effect of appropriate antibiotic therapy (AAT) or IAT against gram-negative bacterial infections in the hospital setting.

Methods

MEDLINE, EMBASE, and Cochrane CENTRAL databases were searched until May 2014 to identify English-language studies examining use of AAT or IAT in hospitalized patients with Gram-negative pathogens. Outcomes of interest included mortality, clinical cure, cost, and length of stay. Citations and eligible full-text articles were screened in duplicate. Random effect models meta-analysis was used.

Results

Fifty-seven studies in 60 publications were eligible. AAT was associated with lower risk of mortality (unadjusted summary odds ratio [OR] 0.38, 95 % confidence interval [CI] 0.30-0.47, 39 studies, 5809 patients) and treatment failure (OR 0.22, 95 % CI 0.14–0.35; 3 studies, 283 patients). Conversely, IAT increased risk of mortality (unadjusted summary OR 2.66, 95 % CI 2.12–3.35; 39 studies, 5809 patients). In meta-analyses of adjusted data, AAT was associated with lower risk of mortality (adjusted summary OR 0.43, 95 % CI 0.23–0.83; 6 studies, 1409 patients). Conversely, IAT increased risk of mortality (adjusted summary OR 3.30, 95 % CI 2.42–4.49; 16 studies, 2493 patients). A limited number of studies suggested higher cost and longer hospital stay with IAT. There was considerable heterogeneity in the definition of AAT or IAT, pathogens studied, and outcomes assessed.

Discussion

Using a large set of studies we found that IAT is associated with a number of serious consequences,including an increased risk of hospital mortality. Infections caused by drug-resistant, Gram-negative organisms represent a considerable financial burden to healthcare systems due to the increased costs associated with the resources required to manage the infection, particularly longer hospital stays. However, there were insufficient data that evaluated AAT for the outcome of costs among patients with nosocomialGram-negative infections.

Conclusions

IAT in hospitalized patients with Gram-negative infections is associated with adverse outcomes. Technological advances for rapid diagnostics to facilitate AAT along with antimicrobial stewardship, surveillance, infection control, and prevention is needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1123-5) contains supplementary material, which is available to authorized users.

Molecular epidemiology of extended-spectrum beta-lactamase (ESBL)-positive Klebsiella pneumoniae from bloodstream infections and risk factors for mortality

The prevalence of extended-spectrum beta-lactamase (ESBL)-positive Klebsiella pneumoniae is growing worldwide. Infections with these bacteria are suspected to be related to increased mortality. We aimed to estimate the distribution of ESBL genotypes and to assess the impact on mortality associated with ESBL positivity in cases of bloodstream infection (BSI) due to K. pneumoniae. We performed a cohort study on patients with K. pneumoniae BSI between 2008 and 2011. Presence of ESBL genes was analyzed by PCR and sequencing. Risk factors for mortality were analyzed by Cox-proportional hazard regression. We identified 286 ESBL-negative (81%) and 66 (19%) ESBL-positive cases. 97% (n = 64) of the ESBL-positive isolates were susceptible for meropenem. The most common ESBL genotypes were CTX-M-15 (60%), SHV-5 (27%) and CTX-M-3 (5%). Significant risk factors for mortality were chronic pulmonary disease (HR 1.747) and moderate/severe renal disease (HR 2.572). ESBL positivity was not associated with increased mortality.

TREM-1 promotes survival during Klebsiella pneumoniae liver abscess in mice

Klebsiella pneumoniae liver abscess (KPLA) is prevalent in East Asia. Liver abscess can develop after translocation of K. pneumoniae from a patient's bowel into the liver via the portal circulation. TREM-1 (triggering receptor expressed on myeloid cells 1) amplifies inflammatory signaling during infection, but its role in KPLA is poorly understood. We used an animal study to characterize the role of TREM-1 in KPLA. We compared survival rates, bacterial burdens in tissues, inflammatory cytokine levels, and histology findings between wild-type and Trem-1 knockout (KO) mice after oral inoculation of capsular type K1 K. pneumoniae. Translocation of K. pneumoniae to mesenteric lymph nodes and liver was examined, and intestinal permeability, antimicrobial peptide expression, and the clearance of K. pneumoniae in the small intestine were determined. In the absence of TREM-1, KPLA model mice showed increased K. pneumoniae dissemination, enhanced liver and systemic inflammation, and reduced survival. Impaired bacterial clearance in the small intestine causes enhanced K. pneumoniae translocation, which renders Trem-1 KO mice more susceptible to K. pneumoniae oral infection. In conclusion, TREM-1-mediated bacterial clearance in the small intestine is an important immune response against K. pneumoniae. TREM-1 deficiency enhances K. pneumoniae translocation in the small intestine and increases mortality rates in mice with KPLA.

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

BACKGROUND

Klebsiella pneumoniae (K. pneumoniae) is the major pathogen of community-acquired pyogenic infections in Taiwan and can lead to poor prognosis in critically ill patients complicated with bacteremia. This study investigated the characteristics and outcome of patients with community-onset K. pneumoniae bacteremia who required intensive care.

METHOD

Adult patients with community-onset K. pneumoniae bacteremia requiring intensive care were retrospectively analyzed, compared with those treated in ordinary wards, and determined for risk factors for infection-related mortality and long-term mortality at a medical center in Taiwan over a 3-year period.

RESULTS

Among the 309 patients with community-onset K. pneumoniae bacteremia, 58 patients (18.8%) required intensive care. Respiratory tract infection [Odds ratio (OR) = 3.67, 95% confidence interval (CI) = 1.79-7.50, p < 0.001] was the independent risk factor for ICU admission. Infection-related mortality was 34.5%. Higher APACHE II score (OR = 1.43; 95% CI = 1.02-2.01; p = 0.041) and underlying malignant neoplasm (OR = 35.48; 95% CI = 2.54-495.57; p = 0.008) were independent predictors of infection-related mortality on multivariate logistic regression. One-year overall mortality was 58.6% and malignant neoplasm was the predisposing factor for poor long-term outcome.

CONCLUSION

Nearly one fifth of patients with community-onset K. pneumoniae bacteremia required intensive care and this was associated with high mortality and poor long-term prognosis. Physicians should recognize the distinct characteristics and risk factors for mortality among these patients.

Characteristics of healthcare-associated and community-acquired Klebsiella pneumoniae bacteremia in Taiwan

OBJECTIVES

Klebsiella pneumoniae is the major cause of community-onset pyogenic infections in Taiwan. We investigated the clinical features and outcomes of community-acquired (CA) and healthcare-associated (HCA) infections among community-onset K. pneumoniae bacteremia.

METHODS

Adult patients with community-onset monomicrobial K. pneumoniae bacteremia were analysed retrospectively at a medical centre in Taiwan over a 4-year period. We compared the clinical characteristics of patients from the CA and HCA groups and identified the risk factors for infection-related mortality.

RESULTS

In a total of 372 patients, HCA infections were observed in 44%. The HCA group had higher Charlson score, the Acute Physiology and Chronic Health Evaluation, version II (APACHE II) score, frequency of malignancy, rates of respiratory tract infection and bacteremia from unknown sources, and higher mortality than the CA group. Diabetes and liver abscess were predominant in the CA group. Whereas old age, APACHE II score >15, malignancy, liver cirrhosis, chronic renal failure, respiratory tract infection, skin and soft tissue infection, and inappropriate antimicrobial therapy were predictors for mortality, HCA bacteremia was not.

CONCLUSIONS

HCA bacteremia showed different characteristics and higher mortality than CA bacteremia, but HCA infection was not an independent risk factor for mortality.