title: Biofilm colonization in chronic treatment refractory infections presenting with discharging sinuses: A study in a tertiary care hospital of Eastern India.
abstract: BACKGROUND
  Treatment refractory chronic recurrent infections mean those chronic infections which recur by same causal agents with similar drug responsiveness after apparent relief following full course of recommended antimicrobial management.
  
  
  METHODS
  Fifty different samples were collected from patients with chronic surgical site infections, laparoscopic port site infections, anal fistula, mesh hernioplasty, chronic dacryocystitis, chronic osteomyelitis, and chronic burn wounds. Samples were processed for culture, identification, antibiotic sensitivity testing using standard microbiological techniques. Biofilm (BF) forming capacity for aerobic organisms were tested by tissue culture plate method. Those for anaerobes and atypical mycobacteria were studied by a novel method using atomic force microscopy (AFM).In vivoBF colonization in lacrimal mucosae of chronic dacryocystitis, patients were studied from histopathological sections by Gram staining, H and E, and fluorescentin situhybridization (FISH).
  
  
  RESULTS
  Out of fifty different samples, sixty-three isolates were obtained in pure culture as follows:Staphylococcus aureus(25.39%),Escherichia coli(14.28%),Klebsiella pneumonia(14.28%),Mycobacterium abscessus(12.69%),Citrobacterspp. (9.52%),Bacteroides fragilis(6.3%),Pseudomonas aeruginosa(4.7%),Proteusspp. (4.7%),Staphylococcus epidermidis(3.1%),Enterobacterspp. (1.5%),Morganella morganii(1.5%), andPeptostreptococcusspp. (1.5%). Among the isolates, 74% were found to be BF producers in the following frequency:P. aeruginosa100%,S. epidermidis100%,B. fragilis100%,Klebsiellaspp. 88.88%,S. aureus81.25%,M. abscessus75%,Citrobacterspp. 83.33%,Proteusspp. 66.66%,E. colispp. 33.33%, andEnterobacterspp. 0%.
  
  
  CONCLUSIONS
  AFM has been proven to be a useful method for detection ofin vitrogrown BF including those for anaerobes and atypical Mycobacteria.In vivoBF detection becomes possible by FISH.S. aureuswas the most common isolate. Among the aerobic isolates,P. aeruginosaandS. epidermidiswere found to be the most common BF producers. Atypical mycobacteria were also found to be BF producers. Diagnosis of BF s in chronic infections significantly changes the management strategy as these infections can no longer be dealt simply with antibiotics alone but require mechanical removal of the foci along with antibiotic coverage for complete cure.
authors.affiliation: Department of Microbiology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India.
authors.forename: Asmita
authors.initials: A
authors.lastname: De
authors.affiliation: Department of Microbiology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India.
authors.forename: Hirak Jyoti
authors.initials: HJ
authors.lastname: Raj
authors.affiliation: Department of Microbiology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India.
authors.forename: Jayeeta
authors.initials: J
authors.lastname: Haldar
authors.affiliation: Department of Biotechnology, Bio-Medical Genomic Centre, Kolkata, West Bengal, India.
authors.forename: Poulami
authors.initials: P
authors.lastname: Mukherjee
authors.affiliation: Department of Microbiology, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India.
authors.forename: Prasanta Kumar
authors.initials: PK
authors.lastname: Maiti
keywords: Atomic force microscopy; biofilm colonization; discharging sinuses