ABSTRACT
Background: Catalase-positive Aerobic Gram-positive non spore forming bacilli, morphologically resembling Corynebacterium diphthriae, commonly called “diphtheroids” or “coryneform” bacteria are placed under order Actinomycetales. Species of Cornybacterium other than diphtheriae were usually either considered as commensals or saprophytes that are present in human, animal and environment. Among more than eighty species of Corynebacerium identified so far, around 53 species have been associated with human or animal infections. The aim of study is to study the species isolation and antibiogram pattern of diphtheroids from various clinical specimens submitted to the department of microbiology, MRH. Methods: All specimens submitted for culture and sensitivity were observed by gram stain and inoculated on Blood agar, Mac conkey agar and Chocolate agar and incubated. Species of Corynebacteriae were identified by biochemical tests like nitrate, urease basic media, and catalase and pyrazinamide reactions. The antibiogram was determined by the disc diffusion method on 5% sheep blood agar. Results: Over a period of one year, a total of 2081 various clinical specimens were screened, among which 1206 were culture positive. 445(36.89%) were positive for diphtheroids and 761(63%) were positive for other organisms. Non diphtherial corynebacterial species like, C. amycolatum (40.6%), C. pseudo-diphtheriticum (12.1%), C. ulcerans (88%), C. urealyticum (64%), C. propinquum (36%), C. xerosis (4.9%) were isolated and identified. Most of the species were sensitive to antibiotics like Vancomycin(88.7%), Teicoplanin(91%), Linezolid(93%) and Clindamycin (82%). High resistant pattern was shown to antibiotics like Penicillin (83.1%), Amoxyclav (86.9%), Chloramphenicol (69.8%), Gentamicin (68.08%) and Tetracycline (64.04%). Conclusion: The present study is an attempt to identify non diphtherial Corynebacterium upto species level and report their antibiogram pattern. Determination of antibiogram of such pathogens is a must, as these species are highly resistant to many of the commonly used antibiotics including Beta-lactams, macrolides, and fluroquinolones. Emergence of multidrug resistance in various species has created the necessity for exact identification of non diphtherial coryneform organisms upto the species level, which helps the clinician to prescribe the antibiotic treatment based on the results of culture and antibiotic sensitivity report.