title: Characterization of nasopharyngeal isolates of type b Haemophilus influenzae from Delhi.
abstract: OBJECTIVE
  Haemophilus influenzae is an important cause of mortality and morbidity among young children in developing countries. Increasing incidence of antibiotic resistance especially production of extended spectrum beta lactamase (ESBL) has made treatment and management of H. influenzae infection more difficult. Nasopharyngeal H. influenzae isolates are excellent surrogate for determination of antibiotic resistance prevalent among invasive H. influenzae isolates. In this study, we characterized nasopharyngeal H. influenzae isolates obtained from healthy school going children in Delhi.
  
  
  METHODS
  Nasopharyngeal H. influenzae isolates were collected from healthy school going children and subjected to serotyping, fimbrial typing and antibiogram profiling. ESBL production was recorded using phenotypic as well as molecular methods. Multi locus sequence typing (MLST) of 13 representative nasopharyngeal H. influenzae isolates was performed as per guidelines.
  
  
  RESULTS
  A significant proportion (26 of 80, 32.5%) of nasopharyngeal isolates of H. influenzae were identified as serotype b. Fimbrial gene (hifA) was detected in 23 (28.75%) isolates. Resistance against commonly prescribed antibiotics (Amp, Tet, Chloro, Septran, Cephalexin) were observed to be high among the nasopharyngeal commensal H. influenzae. Extended spectrum beta lactamase (ESBL) production was observed in a five (6.25%) isolates by both double disk diffusion and molecular typing. MLST identified several novel alleles as well as novel sequence types.
  
  
  CONCLUSIONS
  Our findings showed high resistance against common antibiotics and detection of ESBL in nasopharyngeal H. influenzae isolates collected from normal healthy school going children in Delhi. Detection of H. influenzae type b capsular gene and the presence of fimbrial gene (hif A) suggest virulence potential of these isolates. Discovery of novel alleles and presence of new sequence types (STs) among nasopharyngeal H. influenzae isolates may suggest wider genetic diversity.
authors.affiliation: Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Kandarpa K
authors.initials: KK
authors.lastname: Saikia
authors.forename: Bimal K
authors.initials: BK
authors.lastname: Das
authors.forename: Ramesh K
authors.initials: RK
authors.lastname: Bewal
authors.forename: Arti
authors.initials: A
authors.lastname: Kapil
authors.forename: N K
authors.initials: NK
authors.lastname: Arora
authors.forename: Seema
authors.initials: S
authors.lastname: Sood
mesh_terms: D001483:Base Sequence; D002353:Carrier State; D002648:Child; D017931:DNA Primers; D006193:Haemophilus influenzae / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007194:India; D058885:Multilocus Sequence Typing; D009305:Nasopharynx / Q000382:microbiology*; D016133:Polymerase Chain Reaction
chemical_list: D017931:DNA Primers