title: Diphtheroids-Important Nosocomial Pathogens.
abstract: BACKGROUND
  Diphtheroids are defined as aerobic, non-sporulating, pleomorphic Gram-positive bacilli which are more uniformly stained thanCorynebacterium diphtheriae, lack the metachromatic granules and are arranged in a palisade manner. They are usually commensals of the skin and mucous membranes. They differ fromC.diphtheriaein biochemical rea-ctions as well as in toxin production. Since, they are usually found as commensals on the skin, they are often considered as mere contaminants when isolated from clinical samples. However, there are increasing reports of these organisms being associated with various infections. Hence, we felt the need to study the common species associated with infections and know the properties of these organisms which are otherwise considered as mere laboratory contaminants.
  
  
  OBJECTIVE
  To identify the various species of diphtheroids isolated as pure growth from clinical specimens whose Gram's smear revealed numerous inflammatory cells with Gram positive bacilli and had clinical evidence.
  
  
  METHODS
  A total of 100 isolates of Gram-positive bacilli from 16,242 clinical samples received in the Microbiology Department of Kasturba Medical College were considered for this study from Dec 2013-Dec 2014. Gram-positive bacilli which were seen in the smear along with pus cells, isolated as pure growth and reported as "Corynebacteriumspp having clinical significance" were taken for this study while those which were reported as 'Probable skin contaminants' were excluded from this study. Species identification of Gram-positive bacilli was done by biochemical reactions. Antibiotic susceptibility test was done by Kirby-Bauer disk diffusion method. Biofilm production was done by the microtitre plate method of O'Toole and Kolter and statistical analysis was done by using proportion test and Chi-square test.
  
  
  RESULTS
  Various species of diphtheroids were isolated from different clinical specimens.C. pseudotuberculosis, C. renale, C. ulcerans, C. striatum, C. minutissimum, Corynebacterium haemolyticumisolated from catheter tips, sputum, tracheostomy secretions and wound infections were highly resistant to many antibiotics while isolates from blood namelyC. pseudotuberculosis, C. minutissimum, C. ulceransandC. renalewere nearly sensitive to most of them. It was also interesting to note that there was an increased rate of biofilm production in these isolates.
  
  
  CONCLUSIONS
  Corynebacterium pseudotuberculosis, Coryne- bacterium ulcerans, Corynebacterium renale, Corynebacterium bovis, Corynebacterium striatum, Corynebacterium minutissimum, Corynebacterium pseudodiphtheriticum and Corynebacterium haemolyticummay survive in the form of biofilms in hospitals and cause multidrug resistant infections. Hence, we need to judiciously identify these organisms, find their antimicrobial susceptibility, treat them and thus prevent infections in hospitals.
authors.affiliation: Ex Postgraduate Student, Department of Microbiology, Kasturba Medical College, Manipal University , Mangalore, Karnataka, India .
authors.forename: Reshmi
authors.initials: R
authors.lastname: Chandran
authors.affiliation: Ex Postgraduate Student, Department of Microbiology, Kasturba Medical College, Manipal University , Mangalore, Karnataka, India .
authors.forename: Dinju Raj
authors.initials: DR
authors.lastname: Puthukkichal
authors.affiliation: Associate Professor, Department of Microbiology, Kasturba Medical College, Manipal University , Mangalore, Karnataka, India .
authors.forename: Ethel
authors.initials: E
authors.lastname: Suman
authors.affiliation: Selection Grade Lecturer, Department of Community Medicine, Kasturba Medical College, Manipal University , Mangalore, Karnataka, India .
authors.forename: Shashidhar Kotian
authors.initials: SK
authors.lastname: Mangalore
keywords: Catheter tips; Multidrug resistant; Tracheostomy secretions; Wound infections