title: Virulence profiles and antibiotic susceptibility patterns of Klebsiella pneumoniae strains isolated from different clinical specimens.
abstract: OBJECTIVE
  To detect virulence factors in 54 Klebsiella pneumoniae isolates from different clinical specimens: urine (26), blood (11), pus (11), lung (four), cerebrospinal fluid (one) and ascitic fluid (one).
  
  
  METHODS
  PCR was used to investigate virulence genes encoding adhesins (fimH-1, mrkD, kpn, ycfM), siderophores (entB: enterobactin, iutA: aerobactin, irp-1, irp-2, ybtS, fyuA: yersiniabactin, iroN: catechols receptor), protectines or invasins (rmpA, magA, traT) and toxins (hlyA, cnf-1). The serum resistance, capsule and hypermucoviscosity, and ability to form biofilm and produce siderophores were sought by phenotypic assays. The in vivo virulence was assessed in mice infected by intraperitoneal way. Antimicrobial susceptibility was tested by diffusion method.
  
  
  RESULTS
  The most common virulence genes were fimH-1 (100%), mrkD (96.3%), ycfM (96.3%), and entB (100%). kpn and yersiniabactin genes were found at medium rates of 63% and 46.3% and at lower prevalence, were genes traT (1.8%), iroN (3.7%), iutA (5.5%) and rmpA (3.7%). magA, hlyA and cnf-1 genes were not detected. The capsule, serum resistance, biofilm formation, mannose-sensitive or -resistant haemagglutination and hypermucoviscosity were observed in 100%, 92.6%, 88.8%, 94.4%, 68.5% and 9.2% of isolates, respectively. The prevalence of siderophores was consistent with that of genotypic detection. The LD50 in mice was very low (<10(2) CFUs) for isolates with the most virulence factors. A rate of 74.1% of isolates showed a multidrug resistance (MDR) pattern.
  
  
  CONCLUSIONS
  The distribution of virulence profiles according to the clinical origin suggests a role of enterobactin in urinary infections and yersiniabactin in the invasiveness. The fimbriae F1 and F3, capsule, enterobactin, serum resistance and biofilm formation, were commonly found in isolates, they seem to be at the basis of classic pathogenicity of K. pneumoniae. The invasiveness enhancers, aerobactin, yersiniabactin, catechols receptor, mucoid factor and hypermucoviscosity, detected concomitantly in some isolates, constitute a threat for vulnerable populations, even more if they are in combination with antibiotic resistance.
authors.affiliation: Laboratoire de biologie cellulaire et moléculaire, faculté des sciences biologiques, université des sciences et de la technologie Houari Boumediene, BP 32 El-Alia, Bab Ezzouar, 16111 Alger, Algeria.
authors.forename: R
authors.initials: R
authors.lastname: El Fertas-Aissani
authors.forename: Y
authors.initials: Y
authors.lastname: Messai
authors.forename: S
authors.initials: S
authors.lastname: Alouache
authors.forename: R
authors.initials: R
authors.lastname: Bakour
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D000462:Algeria; D000818:Animals; D018441:Biofilms / Q000254:growth & development; D024881:Drug Resistance, Bacterial; D006761:Hospitals; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity*; D007928:Lethal Dose 50; D051379:Mice; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D017262:Siderophores / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics
chemical_list: D018829:Adhesins, Bacterial; D017262:Siderophores; D037521:Virulence Factors