Detection of serotypes and virulence genes of Klebsiella pneumoniae from feces

Abstract:

ObjectiveTo understand the distribution of serotypes and virulence genes of Klebsiella pneumoniae(KPN) isolated from feces specimens, and provide basis for clinical treatment. MethodsKPN isolated from feces specimens of healthy physical examination people and hospitalized patients without diarrhea in a hospital between November 2013 and June 2014 were collected. Mucoid phenotype, 6 kinds of capsule serotypes（K1, K2, K3, K5, K54, and K57), and 6 kinds of virulence genes （rmpA, fimH, Aero, mrkA, wabG, and ironB）were detected, distribution of capsule serotypes and virulence genes in KPN of different mucoid phenotypes and from different populations were analyzed. ResultsA total of 510 feces specimens were collected, 92 were from healthy physical examination people and 418 from hospitalized patients without diarrhea, 107 strains of KPN were isolated ( 19 from healthy physical examination people, and 88 from hospitalized patients without diarrhea),the total isolation rate of KPN from feces specimens was 20.98%, 24 isolates were hypermucoviscous phenotype KPN (HMVKP) stains, and 83 were nonHMVKP strains. 6 kinds of capsule serotypes and 6 kinds of virulence genes were all detected among KPN, the major were K1, K2, K57, and K54 serotypes(48.60%)；the detection rates of virulence genes mrkA and wabG were the highest (90.65% and 83.18% respectively), simultaneous detection of rmpA+fimH+Aero +mrkA +wabG gene was most common (30.84%), which mainly distributed in K1,K2,K57,and K54 serotypes. rmpA and Aero virulence genes were mainly detected in K1,K2,K57,and K54 serotypes. Among healthy physical examination people, the main serotype of KPN was K1 type（26.32%），while K3 and K57 types were not detected; 6 kinds of capsule serotypes were all  detected from hospitalized patients without diarrhea, the major types were K1, K2, K57, and K54. HMVKP strains carrying 4 kinds of virulence genes was higher than nonHMVKP strains (83.33%［20/24］ vs 32.53%［27/83］, χ2=19.51，P＜0.01). The total detection rate of K1, K2, K57, and K54 serotypes in HMVKP strains were higher than nonHMVKP strains (91.67%［22/24］ vs 36.14%［30/83］）； the detection rates of rmpA and Aero genes were both 95.83%, which were higher than those in nonHMVKP strains (31.32% and 30.12% respectively)( both P＜0.05）. ConclusionHypervirulence capsular serotypes and multiple virulence genes are detected in KPN from feces, especially HMVKP strains and strains from hospitalized patients, which should be paid attention.