Multiplex PCR for Detection of Seven Virulence Factors and K1/K2 Capsular Serotypes of Klebsiella pneumoniae

Compain, Fabrice; Babosan, Anamaria; Brisse, Sylvain; Genel, Nathalie; Audo, Jennifer; Ailloud, Florent; Kassis-Chikhani, Najiby; Arlet, Guillaume; Decré, Dominique

doi:10.1128/jcm.02316-14

Cited by 212 publications

(147 citation statements)

References 28 publications

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“…Several multiplex PCR targeting virulence factors and capsular serotypes have been previously described to help characterize hvKP isolates [Bialek-Davenet et al, 2014;Compain et al, 2014;Turton et al, 2010]. Compared to regular singleplex PCR assays, we found that multiplex PCR is consistent and much quicker in detecting virulent genes and capsular types.…”

Section: Discussionmentioning

confidence: 75%

Clinical and Molecular Analysis of Klebsiella pneumoniae Causing Liver Abscess in China

Sun

Wu²,

Shen

2016

Microb Physiol

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Objective: Hypervirulent Klebsiella pneumoniae (hvKP) has been characterized as the major pathogen associated with the development of liver abscesses. Although the prevalence of K. pneumoniae in liver abscesses in Chinese patients is on the rise, methods for the early laboratory identification and recognition of hvKP are lacking, and hvKP detection and surveillance are thus limited. Methods: A retrospective study was conducted in 240 patients with cultures that were positive for K. pneumoniae, who were hospitalized in the Hospital of Beijing area from May 2013 to August 2014. The clinical and molecular characteristics of K. pneumoniae strains that cause liver abscesses were studied. Thirty-eight (16.7%) of 240 patients positive for K. pneumoniae cultures had liver abscesses. Results: Among these K. pneumoniae isolates, 92.1% (35/38) and 84.2% (32/38) were rmpA and aerobactin (abc) positive, respectively, as indicated by multiplex PCR, while 81.6% (31/38) were string test positive. Intriguingly, K. pneumoniae isolates that were positive for rmpA, abc, or string test accounted for almost all isolates (97.3%; n = 37/38) and thus were defined as hvKP in this study. Based on the new criteria for hvKP, none of these hvKP strains were positive for extended spectrum β-lactamases. Conclusions: Compared to the string test alone, integrating rmpA and abc detection with the string test is robuster and more extensive in the identification of liver abscess-causing hvKP strains. Multiplex PCR assays may therefore accelerate the early laboratory detection of hvKP.

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Section: Discussionmentioning

confidence: 75%

Clinical and Molecular Analysis of Klebsiella pneumoniae Causing Liver Abscess in China

Sun

Wu²,

Shen

2016

Microb Physiol

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“…HV K. pneumoniae likely utilizes this operon for virulence in vivo, as deletion of allS, an activator of the operon involved in this process, resulted in an HV K. pneumoniae strain with significantly reduced virulence based on the 50% lethal dose (LD 50 ) in an intragastric model of infection (361). Along these lines, the presence of this allantoin operon is enriched in strains associated with liver abscess versus commensal strains (224,362). For example, one study found that allS was present in 100% of HV K. pneumoniae isolates from Taiwan but in 0% of K2 isolates and non-K1/K2 isolates from patient blood or liver samples (227), and another study found an association between the presence of allS and the invasiveness of primary liver abscess strains (199).…”

Section: Allantoin Metabolismmentioning

confidence: 84%

Klebsiella pneumoniae: Going on the Offense with a Strong Defense

Paczosa

Mecsas

2016

Microbiol Mol Biol Rev

1,287

1,345

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SUMMARYKlebsiella pneumoniaecauses a wide range of infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Historically,K. pneumoniaehas caused serious infection primarily in immunocompromised individuals, but the recent emergence and spread of hypervirulent strains have broadened the number of people susceptible to infections to include those who are healthy and immunosufficient. Furthermore,K. pneumoniaestrains have become increasingly resistant to antibiotics, rendering infection by these strains very challenging to treat. The emergence of hypervirulent and antibiotic-resistant strains has driven a number of recent studies. Work has described the worldwide spread of one drug-resistant strain and a host defense axis, interleukin-17 (IL-17), that is important for controlling infection. Four factors, capsule, lipopolysaccharide, fimbriae, and siderophores, have been well studied and are important for virulence in at least one infection model. Several other factors have been less well characterized but are also important in at least one infection model. However, there is a significant amount of heterogeneity inK. pneumoniaestrains, and not every factor plays the same critical role in all virulentKlebsiellastrains. Recent studies have identified additionalK. pneumoniaevirulence factors and led to more insights about factors important for the growth of this pathogen at a variety of tissue sites. Many of these genes encode proteins that function in metabolism and the regulation of transcription. However, much work is left to be done in characterizing these newly discovered factors, understanding how infections differ between healthy and immunocompromised patients, and identifying attractive bacterial or host targets for treating these infections.

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“…We conducted cps genotyping of K serotype-specific alleles for K1, K2, K5, K20, K54, and K57 by PCR as previously described (19). Virulence-associated factors, such as the exopolysaccharide synthesis regulator gene (rmpA) and an iron uptake system (aerobactin), were determined by PCR (20,21). Previously reported primers used for PCR were the following: aerobactin forward, 5=-GCATAGGCGGATACGAACAT-3=; aerobactin reverse, 5=-CACAGGGCAATTGCTTACCT-3= (21).…”

mentioning

confidence: 99%

High Prevalence of Hypervirulent Klebsiella pneumoniae Infection in China: Geographic Distribution, Clinical Characteristics, and Antimicrobial Resistance

Zhang

Zhao

Wang

et al. 2016

Antimicrob Agents Chemother

254

273

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Hypervirulent Klebsiella pneumoniae (hvKP) is traditionally defined by hypermucoviscosity, but data based on genetic background are limited. Antimicrobial-resistant hvKP has been increasingly reported but has not yet been systematically studied. K. pneumoniae isolates from bloodstream infections, hospital-acquired pneumonia, and intra-abdominal infections were collected from 10 cities in China during February to July 2013. Clinical data were collected from medical records. All K. pneumoniae isolates were investigated by antimicrobial susceptibility testing, string test, extended-spectrum ␤-lactamase (ESBL) gene detection, capsular serotypes, virulence gene profiles, and multilocus sequence typing. hvKP was defined by aerobactin detection. Of 230 K. pneumoniae isolates, 37.8% were hvKP. The prevalence of hvKP varied among different cities, with the highest rate in Wuhan (73.9%) and the lowest in Zhejiang (8.3%). Hypermucoviscosity and the presence of K1, K2, K20, and rmpA genes were strongly associated with hvKP (P < 0.001). A significantly higher incidence of liver abscess (P ‫؍‬ 0.026), sepsis (P ‫؍‬ 0.038), and invasive infections (P ‫؍‬ 0.043) was caused by hvKP. Cancer (odds ratio [OR], 2.285) and diabetes mellitus (OR, 2.256) appeared to be independent variables associated with hvKP infections by multivariate analysis. Importantly, 12.6% of hvKP isolates produced ESBLs, and most of them carried bla CTX-M genes. Patients with neutropenia (37.5% versus 5.6%; P ‫؍‬ 0.020), history of systemic steroid therapy (37.5% versus 5.6%; P ‫؍‬ 0.020), and combination therapy (62.5% versus 16.7%; P ‫؍‬ 0.009) were more likely to be infected with ESBL-producing hvKP. The prevalence of hvKP is high in China and has a varied geographic distribution. ESBLproducing hvKP is emerging, suggesting an urgent need to enhance clinical awareness, especially for immunocompromised patients receiving combination therapy. Over the past few decades, increasing rates of hypervirulent Klebsiella pneumoniae (hvKP) infection have been reported worldwide (1-4). Such strains are notorious for their capacity to cause serious and metastatic infections in young and healthy individuals, such as pyogenic liver abscesses and endophthalmitis (5). Hypermucoviscosity is an important in vitro parameter for identification of hvKP (6, 7). However, several controversies have arisen regarding the association of hypermucoviscosity phenotype and virulence (8, 9). Hypermucoviscosity-negative strains are more prone to cause severe infections and have a higher mortality rate in diabetic mice than hypermucoviscous K. pneumoniae (8). Our previous study also demonstrated that one of the five hypermucoviscous K. pneumoniae isolates showed high virulence in both in vitro and in vivo assays (9). Therefore, it is apparent that hvKP cannot be defined by string test alone (10). Aerobactin accounts for increased siderophore production and is a major virulence determinant and new defining trait for hvKP based on genetic background (11). Some advances have been made recently...

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Multiplex PCR for Detection of Seven Virulence Factors and K1/K2 Capsular Serotypes of Klebsiella pneumoniae

Cited by 212 publications

References 28 publications

Clinical and Molecular Analysis of <b><i>Klebsiella pneumoniae </i></b>Causing Liver Abscess in China

Clinical and Molecular Analysis of <b><i>Klebsiella pneumoniae </i></b>Causing Liver Abscess in China

Klebsiella pneumoniae: Going on the Offense with a Strong Defense

High Prevalence of Hypervirulent Klebsiella pneumoniae Infection in China: Geographic Distribution, Clinical Characteristics, and Antimicrobial Resistance

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