Virulence characteristics of Klebsiella and clinical manifestations of K. pneumoniae bloodstream infections.
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SUBMITTER: Yu VL
PROVIDER: S-EPMC2878244 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundThe emerging pks-positive (pks+ ) strains have aroused great public concern recently. Colibactin, encoded by pks gene cluster, has been reported to be involved in DNA damage and increased virulence. Little is known about its prevalence among Klebsiella pneumoniae-induced bloodstream infections (BSIs). Therefore, the aim of this study was to investigate the prevalence of pks gene cluster, and molecular and clinical characteristics of K pneumoniae-induced BSIs.MethodsA total of 190 non-duplicate K pneumoniae bloodstream isolates were collected at a university hospital in China from March 2016 to March 2018. Molecular characteristics including capsular types, virulence, and pks genes were detected by polymerase chain reaction (PCR). Clinical characteristics and antimicrobial susceptibility were also investigated.ResultsOverall, 21.6% (41/190) of K pneumoniae bloodstream isolates were hypervirulent K pneumoniae(hvKP). The prevalence of pks gene cluster was 26.8% (51/190). The positive rates of K1, K57, and genes associated with hypervirulence, that is, rmpA, wcaG, mrkD, allS, ybtS, kfu,and iucA, were significantly higher in the pks+ isolates than the pks-negative (pks- ) isolates (P < 0.05), while the pks+ isolates were significantly less resistant to 11 antimicrobial agents than the pks- isolates. Multivariate analysis showed diabetes mellitus, and K1 and K20 capsular types as independent risk factors for pks+ K pneumoniaebloodstream infections.ConclusionsThe pks+ K pneumoniae was prevalent in individuals with bloodstream infections in mainland China. The high rates of hypervirulent determinants among pks+ K pneumoniaerevealed the potential pathogenicity of this emerging gene cluster. Diabetes mellitus, and K1 and K20 capsular types were identified as independent risk factors associated with pks+ K pneumoniaebloodstream infections. This study highlights the significance of clinical awareness and epidemic surveillance of pks+ strains.
| S-EPMC6528554 | biostudies-literature
Project description:Although hypervirulent Klebsiella pneumoniae (hvKp) has been associated with severe community-acquired infections that occur among relatively healthy individuals, information about hvKp infections in health care settings remains limited. Here, we systematically analyzed the clinical and molecular characteristics of K. pneumoniae isolates causing bloodstream infections in a cross-sectional study. Clinical characteristics of K. pneumoniae bloodstream infections from hospitals across Japan were analyzed by a review of the medical records. Whole-genome sequencing of the causative isolates was performed. Bacterial species were confirmed and hvKp were identified using whole-genome sequencing data. Clinical characteristics of hvKp infections were compared with those of non-hvKp infections by bivariate analyses. Of 140 cases of K. pneumoniae bloodstream infections, 26 cases (18.6%) were caused by various clones of hvKp defined by the carriage of cardinal virulence genes. Molecular identification revealed that 24 (17.1%) and 14 (10%) cases were caused by Klebsiella variicola and Klebsiella quasipneumoniae, respectively. Patients with hvKp infections had higher proportions of diabetes mellitus (risk ratio [RR], 1.75; 95% confidence interval [CI], 1.05 to 2.94), and their infections had significantly higher propensity to involve pneumonia (RR, 5.85; 95% CI, 1.39 to 24.6), liver abscess (RR, 5.85; 95% CI, 1.39 to 24.6), and disseminated infections (RR, 6.58; 95% CI, 1.16 to 37.4) than infections by other isolates. More than one-half of hvKp infections were health care associated or hospital acquired, and a probable event of health care-associated transmission of hvKp was documented. hvKp isolates, which are significantly associated with severe and disseminated infections, are frequently involved in health care-associated and hospital-acquired infections in Japan.
| S-EPMC6812994 | biostudies-literature
Project description:BackgroundKlebsiella pneumoniae bloodstream infections (BSIs) occur with significant prevalence and high mortality worldwide. Antimicrobial resistance and virulence are two main factors participating in the pathogenicity of K. pneumoniae. Here we investigated the prevalence of blaKPC and virulence factors in K. pneumoniae isolated from patients with BSIs and their association with clinical outcome.MethodsThe clinical data of 285 K. pneumoniae BSI cases diagnosed from January 2013 to December 2015 in a Chinese university hospital were retrospectively evaluated. The "string test" was performed to identify hypermucoviscous K. pneumoniae (HMKP). blaKPC, rmpA, magA and serotype-specific genes were detected by PCR amplification. Finally, a Cox proportional hazards model was employed to determine the predictors of 14-day mortality.ResultsOf these isolates, the prevalence of blaKPC and rmpA were 33.3% (95/285) and 31.6% (90/285) respectively. 69 isolates (24.2%, 69/285) were HMKP. rmpA was strongly associated with HM phenotype. The KPC-producing KP and HMKP were almost non-overlapping and only three HMKP isolates harbored blaKPC. K1 (28, 40.6%) and K2 (22, 31.9%) were the most common serotypes in HMKP. 44.9% of HMKP BSIs had origin of biliary tract infection or liver abscess. The 14-day mortality was 100% in blaKPC+/HM+ subgroup (3/3), followed by blaKPC+/HM- (39/92, 42.4%), blaKPC-/HM+ (5/66, 7.6%) and blaKPC-/HM- (7/124, 5.6%). The 14-day cumulative survival was significantly different between blaKPC+ and blaKPC- subgroup (Log-rank p?<?0.001) but almost equal between blaKPC-/HM+ and blaKPC-/HM- subgroup (Log-rank p?=?0.578) under the condition of comparable illness severity between blaKPC-/HM+ and blaKPC-/HM- subgroup. Independent risk factors for 14-day mortality were Pitt bacteremia score (HR 1.24, CI 95% 1.13-1.36, p?<?0.001), Charlson comorbidity index (HR 1.24, CI 95% 1.09-1.41, p?=?0.001), septic shock (HR 2.61, CI 95% 1.28-5.35, p?=?0.009) and blaKPC (HR 2.20, CI 95% 1.06-4.54, p?=?0.034).ConclusionsMost of HMKP were antibiotic-susceptible and people infected received appropriate antimicrobial therapy, which may explain the favorable outcome of HMKP BSIs. The KPC-producing HMKP BSIs were scarce but life-threatening. blaKPC was valuable in predicting 14-day mortality.
| S-EPMC6069789 | biostudies-literature
Project description: Not available
| S-EPMC11340057 | biostudies-literature
Project description: Not available
| S-EPMC8574888 | biostudies-literature
Project description:BackgroundCarbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) is gradually becoming the dominant nosocomial pathogens in the healthcare setting.MethodsA retrospective study was conducted on patients with CR-KP from July 2021 to May 2022 in a teaching hospital. We identified bacterial isolates, collected the clinical data, and performed antimicrobial susceptibility testing, hypermucoviscosity string test, antimicrobial and virulence-associated genotype, as well as multi-locus sequence typing. CR-hvKP was defined as the presence of some combination of rmpA and/or rmpA2 with iucA, iroB, or peg-344. SPSS was used for data analysis. Univariate logistic regression analyses were used for risk factor and all statistically significant variables were included in the multivariate model. Statistical significance was taken to be P < 0.05.ResultsA total of 69 non-duplicated CR-KP isolates were collected, 27 of which were CR-hvKP. Out of the 69 CR-KP strains under investigation, they were distributed across 14 distinct sequence types (STs), wherein ST11 exhibited the highest prevalence, constituting 65.2% (45/69) of the overall isolates. The principal carbapenemase genes identified encompassed blakpc-2, blaNDM-1, and blaOXA-48, with blakpc-2 prevailing as the predominant type, accounting for 73.9% (51/69). A total of 69 CR-KP strains showed high resistance to common clinical antibiotics, with the exception of ceftazidime/avibactam. The ST11 (P = 0.040), ST65 (P = 0.030) and blakpc-2 ST11 clones (P = 0.010) were found to be highly related to hvKp. Regarding the host, tracheal intubation (P = 0.008), intracranial infection (P = 0.020) and neutrophil count (P = 0.049) were significantly higher in the patients with CR-hvKP. Multivariate analysis showed tracheal intubation to be an independent risk factor for CR-hvKP infection (P = 0.030, OR = 4.131). According to the clinical data we collected, tracheal intubation was performed mainly in the elderly with severe underlying diseases, which implied that CR-hvKP has become prevalent among elderly patients with comorbidities.ConclusionsThe prevalence of CR-hvKP may be higher than expected in the healthcare setting. CR-hvKP is gradually becoming the dominant nosocomial pathogen, and its prevalence and treatment will be a major challenge. It is essential to enhance clinical awareness and management of CR-hvKP infection.
| S-EPMC10642049 | biostudies-literature
Project description:We investigated the clinical features of bloodstream infections (BSIs) caused by Klebsiella pneumoniae harboring rmpA and molecular characteristics of the bacteria. We retrospectively investigated adult patients with K. pneumoniae BSI from January 2010 to March 2021 at Nagasaki University Hospital. A matched case-control study in a 1:3 ratio was conducted to clarify the clinical and bacterial characteristics of BSI caused by rmpA-positive K. pneumoniae compared with those caused by rmpA-negative isolates. Antimicrobial susceptibility testing and multilocus sequence typing (MLST) were performed for rmpA-positive isolates. The rmpA was detected in 36 (13.4%) of the 268 isolates. Of these 36 isolates, 31 (86.1%) harbored iucA and 35 (97.2%) each possessed peg-344 and iroB; capsular types were identified as K1 in 9 (25.0%) and K2 in 10 isolates (27.8%). Contrarily, of the 108 rmpA-negative isolates, which were matched for case-control studies, 5 isolates (4.6%) harbored iucA and 1 (0.9%) each possessed peg-344 and iroB; 2 (1.9%) and 3 isolates (2.8%) had K1 and K2 capsular types, respectively. Among the rmpA-positive isolates, ST23/K1 (eight isolates) was the most frequent, followed by ST412/non-K1/K2 (seven isolates), ST86/K2 (five isolates), and ST268/non-K1/K2 (four isolates). In a multivariate analysis using clinical factors, liver abscess positively correlated with rmpA-positive isolates, whereas biliary tract infection and use of anticancer drugs negatively correlated with rmpA-positive isolates in patients with K. pneumoniae BSI. Considering the correlation between rmpA-positive isolates and clinical features, rmpA can be used as a marker for understanding the pathophysiology of K. pneumoniae BSI.
| S-EPMC10121676 | biostudies-literature
Project description:Carbapenem-resistant Klebsiella pneumonia (CRKP) infections has become a concerning threat. However, knowledge regarding the characteristics of intestinal CRKP isolates is limited. This study aimed to investigate and compare the clinical, virulence and molecular epidemiological characteristics of intestinal colonization and extraintestinal infections CRKP strains. The clinical characteristics were investigated retrospectively. Polymerase chain reaction was used to investigate the capsular serotype, virulence genes and carbapenemase genes. Capsular polysaccharide quantification assay, serum resistance assay, biofilm formation assay, and infection model of Galleria mellonella larvae were performed to compare the virulence and pathogenicity. Besides, multilocus-sequence-typing (MLST) and pulsed-field-gel-electrophoresis (PFGE) were conducted to explore the homology of intestinal CRKP isolates. A total of 54 intestinal CRKP isolates were included. The main capsular serotypes were K14, K64, and K19. C-reactive protein and the proportion of ICU isolation of the infection group were significantly higher than that of the colonization group (P < 0.05). The carrier rates of various virulence genes of CRKP in the infection group were mostly higher than those in the colonization group, wherein the carrier rates of peg-344 and rmpA were significantly different (P < 0.05). There was no significant difference in capsular polysaccharides, antiserum ability, biofilm formation ability between the two group (P > 0.05), but the lethality of the infection group to Galleria mellonella was significantly higher than that of the colonization group (P < 0.05). The MLST categorized the 54 isolates into 13 different sequence types. PFGE revealed that homology among the 54 CRKP strains was <80%. This study suggested that the CRKP strains in the infection group had higher virulence than those in the colonization group. The development of CRKP isolates colonizing in the intestine should be addressed in future clinical surveillance.
| S-EPMC8678278 | biostudies-literature
Project description:Among Enterobacterales, Klebsiella pneumoniae (Kp) is one of the major opportunistic pathogens causing hospital-acquired infections. The most problematic phenomenon linked to Kp is related to the dissemination of multi-drug resistant (MDR) clones producing carbapenem-hydrolyzing enzymes, representing a clinical and public health threat at a global scale. Over the past decades, high-risk MDR clones (e.g., ST512, ST307, ST101 producing bla KPC-type carbepenemases) have become endemic in several countries, including Italy. Concurrently, the spread of highly virulent Kp lineages (e.g., ST23, ST86) able to cause severe, community-acquired, pyogenic infections with metastatic dissemination in immunocompetent subjects has started to be documented. These clones, designated as hypervirulent Kp (hvKp), produce an extensive array of virulence factors and are highly virulent in previously validated animal models. While the prevalence and distribution of MDR Kp has been previously assessed at local and national level knowledge about dissemination of hvKp remains scarce. In this work, we studied the phenotypic and genotypic features of hypermucoviscous (HMV, as possible marker of increased virulence) Kp isolates from bloodstream infections (BSI), obtained in 2016-17 from 43 Italian Laboratories. Antimicrobial susceptibility testing, whole genome sequencing and the use of two animal models (G. mellonella and murine) were employed to characterize collected isolates. Over 1502 BSI recorded in the study period, a total of 19 Kp were selected for further investigation based on their HMV phenotype. Results showed that hvKp isolates (ST5, ST8, ST11, ST25) are circulating in Italy, although with a low prevalence and in absence of a clonal expansion; convergence of virulence (yersiniabactin and/or salmochelin, aerobactin, regulators of mucoid phenotype) and antimicrobial-resistance (extended-spectrum beta-lactamases) features was observed in some cases. Conventional MDR Kp clones (ST307, ST512) may exhibit an HMV phenotype, but with a low virulence potential in the animal models. To the best of our knowledge, this work represents the first systematic survey on HMV and hvKp in Italy, employing a functional characterization of collected isolates. Future surveillance programs are warranted to monitor the threatening convergence of virulence and resistance among MDR Kp and the spread of hvKp.
| S-EPMC9531727 | biostudies-literature
Project description:Two types of Klebsiella pneumoniae (KP) strains are currently emerging: hypervirulent (hvKP) strains and carbapenem-resistant (CR-KP) strains. To date, these two strain types rarely overlap. Recent reports, however, suggest that CR-KP strains are increasing in virulence. hvKP strains frequently present as highly invasive infections, such as necrotizing skin and soft tissue infections (NSSTI). To examine whether CR-KP strains with features of hvKP were present in our U.S. hospital, we retrospectively identified four cases of CR-KP NSSTI diagnosed between January 2012 and January 2016. Whole-genome sequencing was used to perform multilocus sequence typing, capsular typing, and identification of virulence and antimicrobial resistance genes. Additionally, the virulence of each isolate was determined in vitro and using murine pneumonia and subcutaneous infection models. We identified one CR-KP isolate that possessed features of hypervirulent KP, including a hypermucoviscous phenotype, K2 capsule, and resistance to phagocytosis. Of the four CR-KP isolates, two had no evidence of enhanced pathogenicity in either mouse model, demonstrating that low-virulence strains can cause NSSTI in immunosuppressed patients. The remaining two isolates exhibited low virulence in the pneumonia model but high virulence in the subcutaneous infection model, suggesting that the virulence attributes of these isolates are adapted to causing NSSTI.
| S-EPMC5648777 | biostudies-literature