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Journal of Cancer Research and Therapeutics, Vol. 6, No. 3, July-September, 2010, pp. 374-375 Case Report Corynebacterium macginleyi` a rare bacteria causing infection in an immunocompromised patient Meena Dias1, K Shreevidya1, Suresh D Rao2, Dinesh Shet3 1 Department of Microbiology, Fr. Muller Medical College, Mangalore, India Correspondence Address:Meena Dias, Department of Microbiology, Fr. Muller Medical College, Kankanady, Mangalore - 575 002, India, drmeenadias@gmail.com Code Number: cr10092 PMID: 21119282 DOI: 10.4103/0973-1482.73361 Abstract Corynebacterium species are normal flora of skin and mucous membrane. In recent years, coryneforms have emerged as important opportunistic pathogens in immunocompromised patients. Majority of the Corynebacterium macginleyi isolates are from conjunctiva and cornea. The only reported non ocular isolates are from urinary tract infection, intra-venous catheter related infection, valvular endocarditis and septicaemia. We report herein a rare case of C. macginleyi isolated from tracheostomy site secretions in a patient with carcinoma larynx which was treated successfully with Cefoperazone-sulbactum for seven days and replacing tracheostomy tube. This is the first case of C. macginleyi reported from India. Keywords: Carcinoma larynx, Corynebacterium macginleyi, tracheostomy Introduction Corynebacteria other than C. diphtheriae have been referred to as diphtheroids which form the normal flora of skin and mucous membrane and usually are considered as colonizers and contaminants. Since the number of survivors among severely immunocompromised patients is increasing, there are increased numbers of opportunistic infections due to coryneforms. Some of them show a lipid requirement for growth and these are referred to as lipophilic diphtheroids. [1] One among these lipophilic diphtheroids is C. macginleyi which was described by Riegel et al. in 1995 and was named in honour of Kenneth John McGinley. [2] It was initially isolated solely from the human eye as cause of conjunctivitis. [3],[4] The non ocular reports till date are from a report of urinary tract infection associated with a bladder drainage catheter, [5] intravascular catheter-associated blood-stream infection [6] a case of endocarditis [7] and a case of septicaemia. [8] We report a rare case of C. macginleyi isolated from tracheostomy site from a patient with carcinoma larynx. To the best of our knowledge, this is the first ever case report from India implicating C. macginleyi as a cause of infection. Case Report A 72-year-old man with carcinoma larynx who underwent total laryngectomy and bilateral neck dissection for supraglottic growth and on chemo radiation with weakly carboplatinum (area under coverage 1.5) and radiotherapy for six weeks with total dose of 60 Gy in 30 fractions was admitted with complaints of cough and increased secretions from tracheostomy site. He was a chronic smoker for the past 50 years. There was no other significant past medical history. Physical examination of cardiopulmonary and abdominal system was normal. Laboratory investigations showed h emoglobin 12.3 gm%, total count of 9000 cells/cu mm with differential count of N-70%, L-26% and E-4%. Direct microscopy of the secretion showed numerous polymorph nuclear leucocytes and Gram positive bacilli with palisade arrangement. Diphtheroids were recovered in pure culture after 24 h. This result was dismissed as skin contamination. Since the secretion was not reduced, one more sample was collected. Gram′s stain of the sample showed plenty of PMNL′s with gram positive bacilli. They were non acid-fast, non-motile, non-spore-forming. Albert′s stain showed bacilli with cuneiform arrangement resembling Corynebacterium. Culture on sheep blood agar grew pinpoint non-haemolytic colonies after 48 h of aerobic incubation. The colonies were catalase positive, oxidase negative. Acid was produced from glucose and sucrose fermentation. Based on microscopic examination, colony morphology, biochemical reactions, a preliminary diagnosis of Corynebacterium species was made. It was later confirmed by the API -Coryne system (BioMeriux, France) which identified our strain with a very good profile acceptance (99.4%) as Corynebacterium macginleyi. No other pathogen was isolated. The antimicrobial susceptibility was determined by disc diffusion method and the minimal inhibitory concentration (MIC) was determined on Muller Hinton agar (Himedia) with 5% sheep blood. The isolate was sensitive to amoxyclav, Cefoperazone-sulbactum, imipenem and resistant to Ampicillin, third generation cephalosporins, Amikacin, tetracycline, quinolones and macrolides. He was treated with Cefoperazone-sulbactum 1 g I.V eighth hourly for seven days. Trachestomy tube was replaced. The secretions from the site decreased and his health condition improved and the patient was discharged. Discussion The pleomorphic Gram positive bacilli are commonly isolated from clinical specimens and normally dismissed as non-pathogenic contaminants. This is likely to be true when there is a single, isolated positive culture; however, multiple positive cultures when performed in an appropriate aseptic manner are more indicative of true infection. The coryneforms are being isolated from a variety of body sites, especially in immunocompromised patients. C. macginleyi has been uniquely isolated from ocular surfaces and rarely from other sites. [3],[4],[5],[6],[7],[8] Till date, there are no reports of C. macginleyi isolated from tracheostomy site. In our case, we first interpreted it as probable contaminant. Heavy pure growth obtained from repeated samples in pure culture on different occasions gave us confirmation of the probable role of C. macginleyi as a pathogen. Lipophilic corynebacteria are abundant in moist regions (anterior nares, axila, groin and toe web) and scarce in dry and oily regions. [2] C.macginleyi is a lipophilic bacteria. The number of reported ocular cases suggests that conjunctiva is the main habitat for these bacteria, [3],[4],[9] probably owing to the wetness of the conjunctiva. In our case moisture of the throat might have predisposed the infection; though a study done on the throat of healthy individuals yielded only nonlipophilic corynebacteria. [10] More studies are needed on this topic before considering moisture as a risk factor. Other feature noticed in most of the reported non-ocular cases are indwelling medical devices and damaged cardiac valves, [5],[6],[7],[8] which raises the question whether it is capable of forming biofilms. High-level fluoroquinolone resistance is reported in ophthalmic isolates of C. macginleyi. [4] The same resistance is observed in all the reported non-ocular cases including the present report. Most of the cases reported in the literature are from Europe, Japan. The first isolation from India indicates that it is not restricted to a particular geographical area. Those strains, which are considered pathogenic, are not identified to the species level due to the lack of facilities. This might be the reason for rare reports in the literature from developing countries. But neglecting a pathogen because of the popular thought that it is a contaminant could be dangerous to the patient. This can be avoided by proper identification and appropriate treatment which can prevent complications in the patient. The evidence of infection by C. macginleyi in the non-ocular sites gives an indication that it cannot be termed as an ocular pathogen anymore. With the increase in newer techniques routinely performed in clinical laboratory, non diphtheria corynebacteria are likely to be implicated in a growing number of immunocompromised patients. References
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