Time to positivity of Klebsiella pneumoniae in blood cultures as prognostic marker in patients with intra-abdominal infection: A retrospective study.

Klebsiella pneumoniae is a common causative pathogen of intra-abdominal infection with concomitant bacteraemia, leading to a significant mortality risk. The time to positivity (TTP) of blood culture is postulated to be a prognostic factor in bacteraemia caused by other species. Therefore, this study aimed to investigate the prognostic value of TTP in these patients. The single-centred, retrospective, observational cohort study was conducted between 1 July 2016 and 30 June 2021. All adult emergency department patients with diagnosis of intra-abdominal infection and underwent blood culture collection which yield K. pneumoniae during this period were enrolled. A total of 196 patients were included in the study. The overall 30-day mortality rate was 12.2% (24/196), and the median TTP of the studied cohort was 12.3 h (10.5-15.8 h). TTP revealed a moderate 30-day mortality discriminative ability (area under the curve 0.73, p < 0.001). Compared with the late TTP group (>12 h, N = 109), patients in the early TTP (≤12 h, N = 87) group had a significantly higher risk of 30-day morality (21.8% vs. 4.6%, p < 0.01) and other adverse outcomes. Furthermore, TTP (odds ratio [OR] = 0.79, p = 0.02), Pitt bacteraemia score (OR = 1.30, p = 0.03), and implementation of source control (OR = 0.06, p < 0.01) were identified as independent factors related to 30-day mortality risk in patients with intra-abdominal infection and K. pneumoniae bacteraemia. Therefore, physicians can use TTP for prognosis stratification in these patients.

Acute Exacerbation of Chronic Obstructive Pulmonary Disease Due to Carbapenem-Resistant Klebsiella pneumoniae-Induced Pneumonia: Clinical Features and Prognostic Factors.

Purpose: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is closely related to respiratory tract infection. The aim of this study was to investigate the clinical features and prognostic factors of CRKP-induced pneumonia in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients. Methods: A single-centre, retrospective case-control study on COPD patients hospitalized for acute exacerbation and CRKP-induced pneumonia was conducted from January 1, 2016, to December 31, 2022. The mortality rate of acute exacerbation due to CRKP-induced pneumonia was investigated. The patients were divided into the CRKP-induced pneumonic acute exacerbation (CRKPpAE) group and the non-CRKP-induced pneumonic acute exacerbation (non-CRKPpAE) group, and the clinical characteristics and prognostic factors were compared using univariate analysis and multivariate analysis. Results: A total of 65 AECOPD patients were included, composed of 26 patients with CRKPpAE and 39 patients with non-CRKPpAE. The mortality rate of CRKPpAE was 57.69%, while non-CRKPpAE was 7.69%. Compared with non-CRKPpAE, a history of acute exacerbation in the last year (OR=8.860, 95% CI: 1.360-57.722, p=0.023), ICU admission (OR=11.736, 95% CI: 2.112-65.207, p=0.005), higher NLR levels (OR=1.187, 95% CI: 1.037-1.359, p=0.013) and higher D-dimer levels (OR=1.385, 95% CI: 1.006-1.905, p=0.046) were independently related with CRKPpAE. CRKP isolates were all MDR strains (26/26, 100%), and MDR strains were also observed in non-CRKP isolates (5/39, 12.82%). Conclusion: Compared with non-CRKPpAE, CRKPpAE affects the COPD patient's condition more seriously and significantly increases the risk of death.

Infrared spectroscopy-based machine learning algorithms for rapid detection of Klebsiella pneumoniae isolated directly from patients' urine and determining its susceptibility to antibiotics.

Among the most prevalent and detrimental bacteria causing urinary tract infections (UTIs) is Klebsiella (K.) pneumoniae. A rapid determination of its antibiotic susceptibility can enhance patient treatment and mitigate the spread of resistant strains. In this study, we assessed the viability of using infrared spectroscopy-based machine learning as a rapid and precise approach for detecting K. pneumoniae bacteria and determining its susceptibility to various antibiotics directly from a patient's urine sample. In this study, 2333 bacterial samples, including 636 K. pneumoniae were investigated using infrared micro-spectroscopy. The obtained spectra (27996spectra) were analyzed with XGBoost classifier, achieving a success rate exceeding 95 % for identifying K. pneumoniae. Moreover, this method allows for the simultaneous determination of K. pneumoniae susceptibility to various antibiotics with sensitivities ranging between 74 % and 81 % within approximately 40 min after receiving the patient's urine sample.

[A case of liver abscess with meningitis and endophthalmitis: invasive liver abscess syndrome].

A woman in her 70s was hospitalized and was diagnosed with liver abscess and managed with antibiotics in a previous hospital. However, she experienced altered consciousness and neck stiffness during treatment. She was then referred to our hospital. On investigation, we found that she had meningitis and right endophthalmitis concurrent with a liver abscess. Klebsiella pneumoniae was detected from both cultures of the liver abscess and effusion from the cornea. A string test showed a positive result. Therefore, she was diagnosed with invasive liver abscess syndrome. Although she recovered from the liver abscess and meningitis through empiric antibiotic treatment, her right eye required ophthalmectomy. In cases where a liver abscess presents with extrahepatic complications, such as meningitis and endophthalmitis, the possibility of invasive liver abscess syndrome should be considered, which is caused by a hypervirulent K. pneumoniae.

Patient Characteristics Associated with Concurrent Klebsiella pneumoniae Infection and Severe Pulmonary Tuberculosis.

BACKGROUND: This study aims to investigate the clinical characteristics associated with concurrent Klebsiella pneu-moniae (K. pneumoniae) infection in hospitalized patients with severe pulmonary tuberculosis. METHODS: A retrospective study was conducted on hospitalized severe pulmonary tuberculosis patients between January 2019 and December 2020. Among the 487 patients with severe pulmonary tuberculosis, a positive sputum culture for K. pneumoniae was reported in 76 patients (15.6%, 61 males and 15 females). RESULTS: Among these patients, 27 (35.5%) and 49 (64.5%) patients were with and without K. pneumoniae infection, respectively. Compared to patients without K. pneumoniae infection, patients with K. pneumoniae infection had higher mortality (16.3% vs. 40.7%, p = 0.02), and lower inhibitory/cytotoxic CD8 count (24.2 ± 9.9 vs. 17.8 ± 8.0, p = 0.02), complement C4 (0.3 ± 0.1 vs. 0.2 ± 0.1, p = 0.01), and retinol-binding protein level (32.2 ± 22.2 vs. 22.4 ± 11.8, p = 0.02). Furthermore, the acute Physiology and Chronic Health Evaluation II score was associated with the K. pneumoniae infection in severe pulmonary tuberculosis patients. CONCLUSIONS: It can be concluded that a significant number of severe pulmonary tuberculosis patients can have concurrent K. pneumoniae infection. Immunity, nutritional status, and disease severity are associated with the concurrent infection of K. pneumoniae in these patients.

Case report: A case of high virulence and multidrug resistant Klebsiella pneumoniae liver abscess in Ningxia, China.

RATIONALE: Highly virulent multidrug-resistant Klebsiella pneumoniae (KP) is becoming more and more common in clinical practice, especially the rise of carbapenem-resistant KP in clinical practice, resulting in the emergence of KP liver abscess in Ningxia, China. For the prognosis of liver abscess patients, it is particularly important to identify the types of pathogens and identify antibiotics that are sensitive to the pathogens. PATIENT CONCERNS: A 73-year-old man from China presents to our hospital with abdominal pain, jaundice and fever. Patients have no obvious cause of abdominal pain, abdominal distension, and abdominal pain is persistent. Abdominal examination showed hepatomegaly, no tenderness 2 cm from the right costal margin, abdominal distension and other general examinations did not have obvious abnormalities. He had no history of hypertension and diabetes, ERCP was performed for cholangiocarcinoma 1 year before the current visit, and no significant complications occurred. DIAGNOSES: His initial diagnosis was obstructive cholangitis, and computed tomographic images and liver drainage fluid bacterial culture and genetic polymerase chain reaction tests later determined that the patient had KP liver abscess. INTERVENTIONS: Drainage by liver catheter and antibiotic treatment for 7 weeks. OUTCOMES: The patient liver abscess is basically gone. LESSION: It is particularly important to optimize the diagnosis of liver abscess pathogens for timely and effective treatment of patients.

Development and application of a nomogram model for the prediction of carbapenem-resistant Klebsiella pneumoniae infection in neuro-ICU patients.

IMPORTANCE: Patients in neuro-ICU are at a high risk of developing nosocomial CRKP infection owing to complex conditions, critical illness, and frequent invasive procedures. However, studies focused on constructing prediction models for assessing the risk of CRKP infection in neurocritically ill patients are lacking at present. Therefore, this study aims to establish a simple-to-use nomogram for predicting the risk of CRKP infection in patients admitted to the neuro-ICU. Three easily accessed variables were included in the model, including the number of antibiotics used, surgery, and the length of neuro-ICU stay. This nomogram might serve as a useful tool to facilitate early detection and reduction of the CRKP infection risk of neurocritically ill patients.

Development of a quadruple qRT-PCR assay for simultaneous identification of hypervirulent and carbapenem-resistant Klebsiella pneumoniae.

IMPORTANCE: Globally, the increasing number of hypervirulent Klebsiella pneumoniae (hvKp) and carbapenem-resistant Kp (CR-Kp) infections poses a huge public health challenge with high morbidity and mortality. Worrisomely, due to the mobility of elements carrying virulence and drug-resistance genes, the increasing prevalence of CR-hvKp has also been found with an overwhelming mortality rate in recent years. However, the current detection methods for hvKp and CR-Kp have many disadvantages, such as long turnaround time, complex operation, low sensitivity, and specificity. Herein, a more sensitive, rapid, single-reaction, and multiplex quantitative real-time PCR was developed and validated to differentiate the circulating lineages of Kp with excellent performance in sensitivity and specificity, providing a useful tool for the differential diagnosis and the surveillance of the circulating Kp.

A case of hypervirulent K1-ST23 Klebsiella pneumoniae endocarditis and papillary muscle rupture secondary to multiple site abscesses.

Hypervirulent Klebsiella pneumoniae (hvKP) causes multisite infections and abscesses. However, endocarditis is a rare presentation of hvKP infection. Herein, we report a case of K. pneumoniae native valve infective endocarditis secondary to community-acquired liver and prostate abscesses. The patient developed papillary muscle rupture, leading to mitral regurgitation, and underwent emergent mitral valve replacement. The diagnosis of endocarditis was confirmed microbiologically and histologically. The causative strain belonged to the hypermucoid K1 capsular genotype and possessed the rmpA gene. The genome sequence was deposited in GenBank under the accession number JAQZBZ000000000.

Detection and characterization of putative hypervirulent Klebsiella pneumoniae isolates in microbiological diagnostics.

Hypervirulent Klebsiella pneumoniae strains (hvKp) can cause invasive community-acquired infections in healthy patients of all ages. In this study, the prevalence of putative hvKp in a German tertiary center was investigated and hvKp were characterized by phenotypic and molecular assays. All K. pneumoniae isolates in routine microbiological diagnostics from a single center were screened by string-testing over a period of 6 months. String-test positive (≥ 0.5 mm) isolates were re-evaluated on different media and under various conditions (aerobe, anaerobe). For string-test positive isolates, genes (magA, iutA, rmpA and rmpA2) associated with hypermucoviscosity and hypervirulence were amplified by multiplex PCR. PCR-positive isolates were subjected to whole-genome sequencing and sedimentation and biofilm formation assays. From 1310 screened K. pneumoniae isolates in clinical routine 100 isolates (7.6%) were string test positive. From these, 9% (n = 9) were defined as putative hvKp (string-test+/PCR+). Highest rate of string-test-positive isolates was observed on MacConkey agar under aerobic conditions. Amongst these nine putative hvKp isolates, the international lineage ST23 carrying hvKp-plasmid pKpVP-1 was the most common, but also a rare ST86 with pKpVP-2 was identified. All nine isolates showed hypermucoviscosity and weak biofilm formation. In conclusion, 9% of string-positive, respectively 0.69% of all K. pneumoniae isolates from routine were defined as putative hypervirulent. MacConkey agar was the best medium for hvKp screening.

Pyogenic liver abscess caused by extended-spectrum ß-lactamase-producing hypervirulent Klebsiella pneumoniae diagnosed by third-generation sequencing: a case report and literature review.

We report a case of a woman with diabetes mellitus and choledocholithiasis who had a low fever with chills and severe weakness for 7 days. The patient's abdominal tenderness was positive. Computed tomography and magnetic resonance imaging showed a giant abscess in the liver. The production of extended-spectrum ß-lactamases by hypervirulent Klebsiella pneumoniae was found in the purulent fluid of the liver by nanopore-based metagenomic third-generation sequencing combined with an antibiotic susceptibility test. The patient recovered after intravenous antibiotic therapy and percutaneous drainage. Patients with a history of diabetes mellitus and choledocholithiasis should be aware of the possibility of pyogenic liver abscesses caused by hypervirulent Klebsiella pneumoniae. To rapidly control the development of this disease, nanopore-based metagenomic third-generation sequencing plays an important role not only in rapidly identifying pathogens, but also in guiding the use of antibiotics.

Ultrafast detection of ß-lactamase resistance in Klebsiella pneumoniae from blood culture by nanopore sequencing.

Aim: This study aimed to assess the ultra-fast method using MinION™ sequencing for rapid identification of ß-lactamase-producing Klebsiella pneumoniae clinical isolates from positive blood cultures. Methods: Spiked-blood positive blood cultures were extracted using the ultra-fast method and automated DNA extraction for MinION sequencing. Raw reads were analyzed for ß-lactamase resistance genes. Multilocus sequence typing and ß-lactamase variant characterization were performed after assembly. Results: The ultra-fast method identified clinically relevant ß-lactamase resistance genes in less than 1 h. Multilocus sequence typing and ß-lactamase variant characterization required 3-6 h. Sequencing quality showed no direct correlation with pore number or DNA concentration. Conclusion: Nanopore sequencing, specifically the ultra-fast method, is promising for the rapid diagnosis of bloodstream infections, facilitating timely identification of multidrug-resistant bacteria in clinical samples.

Klebsiella pneumoniae is a bacterium that can cause infections in the blood. These infections can be severe, especially if K. pneumoniae is not susceptible to antibiotics ('antibiotic resistant'). Tools that can detect this resistance are important. In this study, we tested one such tool called MinION™ with blood samples. In 1 h, we were able to identify the bacteria within the sample and their resistance. This type of testing would help clinicians to give the best treatment to patients. More studies are needed to prove the usefulness of MinION for processing samples from real patients.

Classification and prediction of Klebsiella pneumoniae strains with different MLST allelic profiles via SERS spectral analysis.

The Gram-negative non-motile Klebsiella pneuomoniae is currently a major cause of hospital-acquired (HA) and community-acquired (CA) infections, leading to great public health concern globally, while rapid identification and accurate tracing of the pathogenic bacterium is essential in facilitating monitoring and controlling of K. pneumoniae outbreak and dissemination. Multi-locus sequence typing (MLST) is a commonly used typing approach with low cost that is able to distinguish bacterial isolates based on the allelic profiles of several housekeeping genes, despite low resolution and labor intensity of the method. Core-genome MLST scheme (cgMLST) is recently proposed to sub-type and monitor outbreaks of bacterial strains with high resolution and reliability, which uses hundreds or thousands of genes conserved in all or most members of the species. However, the method is complex and requires whole genome sequencing of bacterial strains with high costs. Therefore, it is urgently needed to develop novel methods with high resolution and low cost for bacterial typing. Surface enhanced Raman spectroscopy (SERS) is a rapid, sensitive and cheap method for bacterial identification. Previous studies confirmed that classification and prediction of bacterial strains via SERS spectral analysis correlated well with MLST typing results. However, there is currently no similar comparative analysis in K. pneumoniae strains. In this pilot study, 16 K. pneumoniae strains with different sequencing typings (STs) were selected and a phylogenetic tree was constructed based on core genome analysis. SERS spectra (N = 45/each strain) were generated for all the K. pneumoniae strains, which were then comparatively classified and predicted via six representative machine learning (ML) algorithms. According to the results, SERS technique coupled with the ML algorithm support vector machine (SVM) could achieve the highest accuracy (5-Fold Cross Validation = 100%) in terms of differentiating and predicting all the K. pneumoniae strains that were consistent to corresponding MLSTs. In sum, we show in this pilot study that the SERS-SVM based method is able to accurately predict K. pneumoniae MLST types, which has the application potential in clinical settings for tracing dissemination and controlling outbreak of K. pneumoniae in hospitals and communities with low costs and high rapidity.

Diagnostic tool for surveillance, detection and monitoring of the high-risk clone K. pneumoniae ST15.

BACKGROUND: The global spread of Klebsiella pneumoniae ST15, causing multi-continental outbreaks, contributes to the movement of resistance genes between clones increasing the antimicrobial resistance crisis. The genomic traits providing it with the ability to outcompete other bacteria and cause epidemics remain unclear. AIM: To identify the specific genomic traits of K. pneumoniae ST15 to develop a diagnostic test. METHODS: An outbreak caused by K. pneumoniae occurred in Hospital A Coruña, Spain. Antimicrobial susceptibility analysis and molecular typing (PGFE and MLST) were performed. One isolate of each sequence type was selected for whole-genome sequencing analysis. Comparative analysis of genomes was performed using RAST. BLASTn was used to evaluate the presence of the fhaC and kpiD genes. Two hundred and ninety-four K. pneumoniae from a Spanish nationwide collection were analysed by PCR. FINDINGS: Genotyping showed that 87.5% of the isolates tested belonged to a clone with a unique PFGE pattern which corresponded to ST15. Comparative genomic analysis of the different STs enabled us to determine the specific genomic traits of K. pneumoniae ST15. Two adherence-related systems (Kpi and KpFhaB/FhaC) were specific markers of this clone. Multiplex-PCR analysis with kpiD and fhaC oligonucleotides revealed that K. pneumoniae ST15 is specifically detected with a sensitivity of 100% and a specificity of 97.76%. The PCR results showed 100% concordance with the MLST and whole-genome sequencing data. CONCLUSION: K. pneumoniae ST15 possesses specific genomic traits that could favour its dissemination. They could be used as targets to detect K. pneumoniae ST15 with high sensitivity and specificity.

Rapid determination of colistin resistance in Klebsiella pneumoniae by MALDI-TOF peak based machine learning algorithm with MATLAB.

INTRODUCTION: To date, limited data exist on demonstrating the usefulness of machine learning (ML) algorithms applied to MALDI-TOF in determining colistin resistance among Klebsiella pneumoniae. We aimed to detect colistin resistance in K. pneumoniae using MATLAB on MALDI-TOF database. MATERIALS AND METHODS: A total of 260 K. pneumoniae isolates were collected. Three ML models, namely, linear discriminant analysis (LDA), support vector machine, and Ensemble were used as ML algorithms and applied to training data set. RESULTS: The accuracies for the training phase with 200 isolates were found to be 99.3%, 93.1%, and 88.3% for LDA, support vector machine, and Ensemble models, respectively. Accuracy, sensitivity, specificity, and precision values for LDA in the application test set with 60 K. pneumoniae isolates were 81.6%, 66.7%, 91.7%, and 84.2%, respectively. CONCLUSION: This study provides a rapid and accurate MALDI-TOF MS screening assay for clinical practice in identifying colistin resistance in K. pneumoniae.

Klebsiella pneumoniae infection in cynomolgus monkeys at primate research center facility in Indonesia.

BACKGROUND: Klebsiella pneumoniae infection in nonhuman primates has been widely reported and causes significant morbidity and mortality. Animal deaths occur routinely at the Primate Research Center of IPB University. The results of necropsy and culture suggested a K. pneumoniae infection. METHODS: A mass health assessment of Cynomolgus monkeys (n = 429) was carried out by physical examination and molecular targeting K. pneumoniae (n = 96), family of Coronaviridae (n = 148) and Paramyxoviridae (n = 148). RESULTS: A total of 49.18% of the animals had clinical symptoms of respiratory disorders, abscesses, trauma, and others. PCR results indicated that 28.57% were positive for K. pneumoniae with 35.71% mortality, while all samples were negative for both virus families. CONCLUSIONS: There have been outbreaks caused by K. pneumoniae and/or K. pneumoniae subsp. pneumoniae. This disease is chronic, infects all of the buildings, and no tendency for disease transmission according to gender and age class.

[Advances in the diagnosis and treatment strategy of polymyxin resistant Klebsiella pneumoniae].

In recent years, the detection rate of multidrug-resistant and pandrug-resistant Klebsiella pneumoniae has increased year on year, so polymyxin has received increasing attention as an antibiotic that is still sensitive to most of the multidrug-resistant strains. However, widespread use of polymyxin is likely to lead to the emergence of polymyxin-resistant Klebsiella pneumoniae. At the same time, the polymyxin hetero-resistance has made clinical prevention and treatment difficult. In addition to relying on the combination of polymyxins with other antibiotics, the search for new antibacterial drugs has also become a research hotspot. Research into early detection methods for polymyxin resistance can also help to optimize and improve the diagnosis and treatment strategies. This article reviewed the epidemic status, mechanism, detection methods and prevention measures of polymyxin-resistant Klebsiella pneumoniae.