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Indian Journal of Medical Microbiology, Vol. 25, No. 4, October-December, 2007, pp. 413-415 Case Report Cutaneous actinomycosis: A rare case Metgud SC, Sumati H, Sheetal P Department of Microbiology, JN Medical College, Belgaum - 590 010, Karnataka Correspondence Address: Department of Microbiology, JN Medical College, Belgaum - 590 010, Karnataka, India. Email: us_c2004@yahoo.co.in. Date of Submission: 06-Apr-2007 Code Number: mb07113 Abstract Cutaneous actinomycosis is a rare presentation. Here we present a case of cutaneous actinomycosis with no history of trauma or systemic dissemination. The isolate was identified as Actinomyces viscosus by standard methods. The isolate was found to be penicillin resistant by Kirby Bauer disc diffusion method. Therefore, the patient was treated with cotrimoxazole and improved. Thus, this case highlights the importance of isolation and susceptibility testing in actinomycotic infection. The sinuses have healed, and the patient has recovered. Keywords: Cutaneous actinomycosis, Actinomyces viscosus Actinomycosis is subacute to chronic, suppurative granulomatous disease that tends to produce draining sinus tracts. This usually manifests as cervicofacial, thorasic or abdominal actinomycosis. Cutaneous actinomycosis is extremely rare. [1] The reports of cutaneous actinomycosis are from wounds contaminated with saliva or as a consequence of hematogenous dissemination following a dental procedure. [1],[2] There are case reports in literature of primary cutaneous actinomycosis. The common isolates are Actinomyces naeslundii, A. israelii, A. meyeri and rarely A. odontolyticus in humans. [3] Here we report a rare case of cutaneous actinomycosis of the back, from which A.viscosus was isolated. To the best of our knowledge, this is the first case of isolation of A.viscosus from primary cutaneous actinomycosis in human. The isolate has been reported in animals. [4] Case Report A 35-year-old lady, farmer by occupation, visited our hospital with complaints of spreading type of multiple discharging wounds on the back since seven years, fever and throbbing type of pain at the site since 1 month. It started as a swelling of 3 cm diameter that gradually increased in size. She consulted a local doctor who treated her with oily suspension for local application. However, the swelling gave rise to discharging wounds spreading to the surrounding area. A local doctor treated her with antitubercular drugs for 9 months, with no cure. She was referred to the skin OPD of our hospital. On local examination, multiple discharging sinuses extending over an area 12 x 15 cm on back, with reactive kyphosis were found. Her haemoglobin level was 9.5 gm% and ESR was 40 mm at the end of 1 h. Total count, differential count, serum total protein and albumin and Albumin/globulin ratio were within normal limits. HIV-ELISA was non-reactive; random blood sugar was 120 mg% and X-ray of chest showed no involvement of lungs or vertebra. Histopathology of the biopsy was reported to be actinomycosis. The aseptically collected pus sample and sinus tract tissue biopsy were received in our laboratory. Sinus tract tissue was macerated and processed. A part of the pus sample was centrifuged to obtain the white granules. Crushed granules showed branching filaments. Gram stain of pus sample showed pus cells, gram positive cocci in clusters and Gram positive non-sporing long filamentous bacilli. Modified Ziehl Neelsen (1% H 2SO4 ) staining showed non-acid-fast bacilli. Samples were inoculated for culture on duplicate plates of chocolate agar, blood agar and Sabouraud dextrose agar. One set was incubated in CO2 jar and another under aerobic conditions at 37 °C. The set of culture plates incubated under aerobic conditions yielded the growth of Staphylococcus aureus. The set of culture plates incubated in CO2 jar showed two types of colonies on third day. The golden yellow, opaque, β -hemolytic, circular colonies were identified to be of S. aureus. Both the S.aureus isolates were resistant to penicillin, sensitive to ciprofloxacin, erythromycin, gentamicin, cefuroxime, cotrimoxazole by Kirby Bauer disc diffusion method. The other colonies were flat irregular grey non-hemolytic moist with smooth glistening surface. The Gram stain of the colony showed gram positive bacilli about 3-5 x 0.1 μm, branching with rounded ends. The modified Ziehl Neelsen staining showed non-acid-fast bacilli. The colonies were identified to be Actinomycetes species. The speciation was done accordingly by a battery of tests [Table - 1]. The Actinomycete was identified as Actinomyces viscosus. [5] The antibiotic susceptibility was carried out by Kirby Bauer disc diffusion method. [6] The strain was resistant to penicillin and sensitive to cefuroxime, cotrimoxazole, gentamicin, amikacin and augmentin. No growth was observed on Sabouraud dextrose agar. Discussion Clinically, the patient was diagnosed to have mycetoma. Primary cutaneous actinomycosis is usually diagnosed as mycetoma by virtue of location, induration, sinus tracts and granules in the pus. However, mycetoma and actinomycosis are distinct and separate clinical entities because of their different pathogenesis and etiologic agents. A. israelii is the species isolated from most cases of cutaneous actinomycosis; A. actinomadurae and Nocardia spp. are the common etiologic agents of actinomycetoma. [7] In Actinomycetedales, Streptomyces spp are inherently resistant strain; Nocardia species are resistant to penicillin whereas Actinomyces spp. are sensitive to almost all drugs. In eumycotic mycetoma, antifungals are drug of choice. Culture and in vitro antibiotic susceptibility testing is the main mode of diagnosis of etiologic agent. Gram stain smears revealed the presence of gram positive filamentous non-sporing bacilli along with the gram positive cocci in clusters. The presence of concomitant bacteria leads us to the diagnosis of actinomycosis. Actinomycosis is caused by a number of facultative anaerobic Actinomycetes. Concomitant bacteria, S. aureus, favour the growth of anaerobic Actinomycetes. However, on gram stain, from actinomycetoma, only actinomycete species are seen. [1] A. viscosus is considered a pathogenic species because of its aggregative property. A. viscosus serotype II is isolated from human cases. [8] We have not conducted serotyping. A. viscosus has not been reported from cutaneous actinomycoses so far. Actinomyces species are known to be susceptible to almost all antibiotics. β-lactam antibiotics are effective drugs against Actinomyces. In vitro antibiotic susceptibility testing for Actinomycetedales is problematic. A few studies have evaluated conventional methods of antibiotic sensitivity testing and have studied the susceptibility pattern of various Actinomycete species. [6],[9] Rapidly growing isolates, as is true with the present isolate, allow testing by disc diffusion method, and the results are comparable to minimum inhibitory concentration technique by broth dilution. [6] The present isolate is resistant to Penicillin. Actinomyces acquire resistance from concomitant bacteria. [1] In addition, associated organisms, which produce β-lactamases, can complicate treatment. Therefore, the dense granules of Actinomyces and the presence of associated bacteria can enhance the virulence of infection and influence the mode of use of antibiotics, thereby adding to the difficulty of treating the disease. [10] In the present case, A. viscosus and S. aureus were resistant to penicillin. The patient was on treatment with penicillin. Later, the patient improved with treatment with cotrimoxazole. Thus, this case highlights the importance of isolation and susceptibility testing in actinomycotic infection. The sinuses have healed, and the patient recovered. References
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