title: Time dependent enhanced resistance against antibiotics & metal salts by planktonic & biofilm form of Acinetobacter haemolyticus MMC 8 clinical isolate.
abstract: OBJECTIVE
  Available literature shows paucity of reports describing antibiotic and metal resistance profile of biofilm forming clinical isolates of Acinetobacter haemolyticus. The present study was undertaken to evaluate the antibiotic and metal resistance profile of Indian clinical isolate of A. haemolyticus MMC 8 isolated from human pus sample in planktonic and biofilm form.
  
  
  METHODS
  Antibiotic susceptibility and minimum inhibitory concentration were determined employing broth and agar dilution techniques. Biofilm formation was evaluated quantitatively by microtiter plate method and variation in complex architecture was determined by scanning electron microscopy. Minimum biofilm inhibiting concentration was checked by Calgary biofilm device.
  
  
  RESULTS
  Planktonic A. haemolyticus MMC 8 was sensitive to 14 antibiotics, AgNO 3 and HgC1 2 resistant to streptomycin and intermediately resistant to netilmycin and kanamycin. MMC 8 exhibited temporal variation in amount and structure of biofilm. There was 32-4000 and 4-256 fold increase in antibiotic and metal salt concentration, respectively to inhibit biofilm over a period of 72 h as against susceptible planktonic counterparts. Total viable count in the range of 10(5)-10(6) cfu / ml was observed on plating minimum biofilm inhibiting concentration on Muller-Hinton Agar plate without antimicrobial agents. Biofilm forming cells were several folds more resistant to antibiotics and metal salts in comparison to planktonic cells. Presence of unaffected residual cell population indicated presence of persister cells.
  
  
  CONCLUSIONS
  The results indicate that biofilm formation causes enhanced resistance against antibiotics and metal salts in otherwise susceptible planktonic A. haemolyticus MMC 8.
authors.forename: Sharvari Vijaykumar
authors.initials: SV
authors.lastname: Gaidhani
authors.forename: Aartee Vishnu
authors.initials: AV
authors.lastname: Raskar
authors.forename: Sharmishtha
authors.initials: S
authors.lastname: Poddar
authors.forename: Shriya
authors.initials: S
authors.lastname: Gosavi
authors.forename: Praveen Kishore
authors.initials: PK
authors.lastname: Sahu
authors.forename: Karishma Rajendra
authors.initials: KR
authors.lastname: Pardesi
authors.forename: Shobhana V
authors.initials: SV
authors.lastname: Bhide
authors.affiliation: Institute of Bioinformatics & Biotechnology, University of Pune, Pune, India.
authors.forename: Balu Ananada
authors.initials: BA
authors.lastname: Chopade
mesh_terms: D000150:Acinetobacter / Q000187:drug effects* / Q000254:growth & development; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D018441:Biofilms / Q000187:drug effects*; D024881:Drug Resistance, Bacterial; D006801:Humans; D008670:Metals / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010933:Plankton / Q000187:drug effects; D012492:Salts / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D008670:Metals; D012492:Salts