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Network Integrative Genomic and Transcriptomic Analysis of Carbapenem-Resistant Klebsiella pneumoniae Strains Identifies Genes for Antibiotic Resistance and Virulence.

ABSTRACT: Global increases in the use of carbapenems have resulted in several strains of Gram-negative bacteria acquiring carbapenem resistance, thereby limiting treatment options. Klebsiella pneumoniae is a common carbapenem-resistant pathogenic bacterium that is widely studied to identify novel antibiotic resistance mechanisms and drug targets. Antibiotic-resistant clinical isolates generally harbor many genetic alterations, and the identification of responsible mutations would provide insights into the molecular mechanisms of antibiotic resistance. We propose a method to prioritize mutated genes responsible for antibiotic resistance on the basis of expression changes in their local subnetworks, hypothesizing that mutated genes that show significant expression changes among the corresponding functionally associated genes are more likely to be involved in the carbapenem resistance. For network-based gene prioritization, we developed KlebNet (www.inetbio.org/klebnet), a genome-scale cofunctional network of K. pneumoniae genes. Using KlebNet, we reconstructed the functional modules for carbapenem resistance and virulence and identified the functional association between antibiotic resistance and virulence. Using complementation assays with the top candidate genes, we were able to validate a novel gene that negatively regulated carbapenem resistance and four novel genes that positively regulated virulence in Galleria mellonella larvae. Therefore, our study demonstrated the feasibility of network-based identification of genes required for antibiotic resistance and virulence of human-pathogenic bacteria.IMPORTANCE Klebsiella pneumoniae is a major bacterial pathogen that causes pneumonia and urinary tract infections in human. K. pneumoniae infections are treated with carbapenem, but carbapenem-resistant K. pneumoniae has been spreading worldwide. We are able to identify antimicrobial-resistant genes among mutated genes of the antibiotic-resistant clinical isolates. However, they usually harbor many mutated genes, including those that cause weak or neutral functional effects. Therefore, we need to prioritize the mutated genes to identify the more likely candidates for the follow-up functional analysis. For this study, we present a functional network of K. pneumoniae genes and propose a network-based method of prioritizing the mutated genes of the resistant clinical isolates. We also reconstructed the network-based functional modules for carbapenem resistance and virulence and retrieved the functional association between antibiotic resistance and virulence. This study demonstrated the feasibility of network-based analysis of clinical genomics data for the study of K. pneumoniae infection.

SUBMITTER: Lee M

PROVIDER: S-EPMC6589436 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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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.

Project description:Colistin has been considered a last-line option for the treatment of infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP). Heterogeneous resistance to colistin leads to unexplained clinical colistin treatment failure for CRKP. Our study aimed to investigate the extent of colistin heteroresistance among CRKP strains in China. A total of 455 colistin-susceptible strains, collected from six tertiary care hospitals in China, were characterized. The overall rate of colistin heteroresistance was 6.2%, as determined by the population analysis profiles (PAPs). Genomic analysis revealed that 60.7% of the colistin-heteroresistant isolates belonged to the epidemic sequence type 11 (ST11) clone. Single-nucleotide polymorphisms (SNPs) suggested that 6 ST5216 strains shared the same origin. Each of the subpopulations had a ≥8-fold decrease in colistin MIC in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), which indicated that heteroresistance could be suppressed by an efflux pump inhibitor. In addition, our results suggested that the PhoPQ pathway plays an important role in the mechanisms of heteroresistance. IMPORTANCE The problem of CRKP has raised alarms concerning global health. Our study enriches the epidemiological study of colistin heteroresistance among CRKP strains in China, where the prevalence of this phenomenon was previously unknown. Importantly, colistin-heteroresistant strains may cause the failure of clinical treatment with colistin, even if the clinical laboratory reports that the strains are sensitive. The commonly used broth microdilution method is unable to detect this special phenomenon. Additionally, our results indicate that efflux pumps play a major role in colistin heteroresistance, and inhibitors can effectively reverse it. Our study is the first to provide a detailed analysis of the prevalence of colistin heteroresistance in China, as well as an analysis of the genetic mechanisms of this phenomenon.

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Network Integrative Genomic and Transcriptomic Analysis of Carbapenem-Resistant Klebsiella pneumoniae Strains Identifies Genes for Antibiotic Resistance and Virulence.

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