title: Characterization of Escherichia coli Phylogenetic Groups Associated with Extraintestinal Infections in South Indian Population.
abstract: BACKGROUND
  Escherichia coli strains mainly fall into four phylogenetic groups (A, B1, B2, and D) and that virulent extra-intestinal strains mainly belong to groups B2 and D.
  
  
  OBJECTIVE
  The aim was to determine the association between phylogenetic groups of E. coli causing extraintestinal infections (ExPEC) regarding the site of infection, expression of virulence factors, antimicrobial resistance patterns, and clinical outcome. This descriptive study was carried out in a multi-specialty Tertiary Care Hospital.
  
  
  METHODS
  A total of 300 E. coli causing ExPEC were studied. Triplex polymerase chain reaction was used to classify the phylogenetic groups; hemolysin production was assessed on sheep blood agar and biofilm production in a microtiter plate assay. Production of extended spectrum of beta-lactamase (ESBLs) was detected by combination disk method; AmpC was detected by AmpC disk test, Carbapenemase production was detected by modified Hodge test and metallo-β-lactamase by metallo-beta-lactamases (MBL) E-test.
  
  
  RESULTS
  Of 300 isolates, 61/300 (20%) belonged to phylogroup A, 27/300 (9%) to phylogroup B1, 104/300 (35%) were B2 and 108/300 (36%) belonged to group D, respectively. Phylogroups B2 and D were the most predominant groups in urinary tract infection and sepsis. Prognoses were better in infections with group A and B1 isolates, and relapses and death were common in infections with B2 and D. Expression of biofilm was greatest in B1 and hemolysin in group B2. Group A and B1 showed higher resistance to ciprofloxacin and were most frequent β-lactamase (ESBL, AmpC, Carbapenemase and MBL) producers.
  
  
  CONCLUSIONS
  Phylogenetic group B2 and D were predominant in ExPEC and exhibited least antimicrobial resistance among the groups. Resistance to multiple antibiotics was most prevalent in group A and B1. Regular monitoring of antimicrobial susceptibility in commensal strains is essential as they might transfer the property of antimicrobial resistance to pathogenic strains.
authors.affiliation: Department of Microbiology Moti Lal Nehru Medical College, Allahabad, Uttar Pradesh, India.
authors.forename: A
authors.initials: A
authors.lastname: Chakraborty
authors.affiliation: Department of Microbiology, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: V
authors.initials: V
authors.lastname: Saralaya
authors.affiliation: Department of Medicine, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: P
authors.initials: P
authors.lastname: Adhikari
authors.affiliation: Department of Microbiology, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: S
authors.initials: S
authors.lastname: Shenoy
authors.affiliation: Department of Microbiology, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: S
authors.initials: S
authors.lastname: Baliga
authors.affiliation: Department of Microbiology, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: A
authors.initials: A
authors.lastname: Hegde
keywords: Drug resistance; Escherichia coli; Extraintestinal infections; Phylogenetic group; Polymerase chain reaction; Virulence