Prosthetic valve endocarditis due to Mycobacterium fortuitum S.L. NARASIMHAN,* MD; T.W. AUSTIN, MD, FRCP[C]

Infection with Mycobacterium fortuitum, a rapidly growing mycobacterium that does not cause tuberculosis, occurs most often in association with abscess formation or indolent lung disease. It is usually chronic, occasionally remitting spontaneously, and does not respond to conventional antituberculous treatment. Widespread disseminated infection is

days, then with tetracycline orally for 5 weeks. While he was receiving this therapy increasing swelling and tenderness of the sternotomy incision developed. He was noted to have persistent

tachycardia and low blood pressure, and he lost 16 kg over 5 weeks. The patient was transferred to our hospital 10 weeks after valve replacement because of persistent fever and increasing fatigue. He was cachectic

rare."2

and pale, with a pulse rate of 120

In this report we describe a patient in whom endocarditis due to M. fortuitum developed after aortic valve replacement. A review of the literature revealed no previous reports of endocarditis due to this organism involving either a natural or a prosthetic valve.

beats/mm, a blood pressure of 110/74

Case report A 57-year-old man underwent aortic

valve replacement because of rheumatic valvular disease. He received cloxacillin and ampicillin prophylactically for 7 days during and after surgery. He was discharged from hospital a month later following an uneventful recovery.

He was admitted to a second hospital a week later because of fever, severe fatigue and an irregular heart rhythm. Several cultures of blood taken at that time grew a gram-positive - bacillus sensitive to kanamycin and tetracycline. This organism was later identified as M. fortuitum. The patient was treated with kanamycin intravenously for 10 From the departments of medicine and microbiology, Victoria Hospital and University of Western Ontario, London *Present address: Department of medicine, General Hospital, Forest Road, St. John's, Nfld. AlA 1E5 Reprint requests to: Dr. T.W. Austin, Department of medicine, Victoria Hospital, London, Ont. N6A 4G5

mm Hg and a temperature of 38.50C. Chest findings were normal except for a grade 2/4 midsystolic murmur in the aortic area; the sounds of the prosthetic valve were heard well. The liver and spleen were not enlarged. There was an erythematous, tender swelling of the entire sternal area. The femoral incision appeared not to be infected. Splinter hemorrhages were seen in the nails of

the left thumb and the right second finger. There was no clubbing. Significant laboratory findings included normocytic, normochromic anemia (hemoglobin value 9.5 g/dL), a leukocyte count of 4.8 x 109/L with a normal differential count and an elevated erythrocyte sedimentation rate (80 mm/h, Westergren). Urinalysis showed microscopic hematuria. Scmtiscanning with 67Ga-gallium citrate (New England Nuclear, North Billerica, Massachusetts) gave results consistent

with those of osteomyelitis of the sternum.

Acid- and alcohol-fast bacilli were seen in smears of material draining from the sternotomy wound, and cultures of blood and of material from the sternotomy wound repeatedly yielded

a rapidly growing, nonpigmented mycobacterium identified as M. fortuitum by the laboratories of the Ontario Ministry of Health in Toronto. This organism was found to be sensitive to ethionamide and resistant to isoniazid, rifampin, ethambutol, streptomycin, kanamycin, capreomycin, para-aminosali-

154 CMA JOURNAL/JULY 22, 1978/VOL. 119

cylic acid, pyrazinamide and cycloserine. On the 14th hospital day the entire sternum was removed and therapy was started with ethionamide (1 g/d), isoniazid (300 mg/d), rifampin (600 mg/d) and streptomycin (1 g/d). The fever continued and 1 week after initiation of the antituberculous treatment a grade 3 / 6 pandiastolic murmur over the base of the heart and the left sternal border and increasing congestive heart failure appeared. The sounds of the prosthetic valve were markedly diminished. Left-sided upper motor neuron facial weakness, symmetrically brisk deep tendon refleKes and an extensor

plantar response on the left were noted. His condition deteriorated rapidly and he died the next day. Culture of a blood sample obtained just before death again grew M. fortuitum. Permission for autopsy was not obtained.

Discussion M. fortuitum is a member of the M. fortuitum complex, one of the 10 species complexes composed of the presently known clinically significant mycobacterial pathogens.' This organism was previously classified as a

rapidly growing Runyon group IV mycobacterium.4 It produces nonpigmented colonies visible in less than 1 week on a variety of media, including L6wenstein-Jensen medium. It is

niacin-negative and aryl-sulfatasepositive, and may be grown on MacConkey's agar. M. fortuitum closely resembles M. chelonei, from which it may be differentiated by colony type on corn meal and 7 H-i 1 agar plates,3 and by the fact that M. fortuitum reduces nitrate, utilizes citrate and is serologically distinct.5 M. fortuitum is widely distributed in soil and water and has been isolated from house dust, raw and pas-

teurized milk, fish, frogs, cattle and the sputum and saliva of healthy adult humans.6-" This organism has been regarded as nonpathogenic in healthy individuals although it has shown pathogenicity in compromised? hosts.11 The most common M. fortuitum infections, cutaneous lesions and abscesses, almost always occur after trauma such as injections, gunshot wounds, motorcycle accidents and gardening injuries.10 Other reported types of infection include pulmonary infection,10'13'14 keratitis,'5 meningitis with a cauda equina abscess,10 peritonitis, salpingitis, prostatitis, epididymitis,5 osteomyelitis,16 disseminated mycobacteriosis,1" joint and bursal infections following steroid injection17 and postoperative infection following abdominal surgery.10 Prosthetic valve endocarditis remains a devastating though infrequent complication of heart valve replacement. Altmann and colleagues18 recently described a 45-year-old man in whom endocarditis due to M. chelonci developed following aortic valve replacement. The probable sequence of events in our patient appears to be infection of the sternotomy wound by M. fortuitum, leading to sternal osteomyelitis and septicemia, and followed by infection of the prosthetic heart valve as evidenced clinically by development of a new aortic regurgitant murmur, marked diminution of sounds of the prosthetic valve and onset of increasing heart failure. The neurologic findings before death suggested a lesion of the right hemisphere, most likely due to emboli from the site of the prosthetic valve. A prosthetic valve contaminated before insertion may also serve as the source of the organism, as suggested by the recent reports of contamination of porcine aortic valves by atypical mycobacteria.19'20 Recently the Center for Disease Control in Atlanta, Georgia reported two outbreaks of postoperative wound infection due to M. fortuitum in 24 patients who had undergone open heart surgery.21 Because of the resistance exhibited by M. fortuitum complex to many antituberculous drugs and the potential seriousness of these infections in patients with prosthetic heart valves, early recognition of postoperative mycobacterial wound infection appears to be critical. A Gram-stained smear of the

material draining from the sternotomy wound may reveal gram-positive bacilli, and routine cultures may be reported as sterile or positive only for skin flora since M. fortuitum may take up to 5 days to appear on blood agar and MacConkey's agar. If detected on routine culture media these organisms may resemble diphtheroids in colonial morphology and Gramstaining. Routine staining and culture of material for acid-fast bacteria from the infected stemotomy wound of patients who have undergone heart valve replacement may obviate this problem. Infections due to M. fortuitum complex may cause difficult therapeutic problems. Many of the invasive strains have been found to be resistant to all available antituberculous drugs.'. Besides treatment with combinations of antituberculous agents, surgical excision of the lesions whenever possible has been suggested. No single antimicrobial agent or combination of drugs has been shown to be consistently useful, and empiric combinations of rifampin plus erythromycin, oxacillin plus kanamycin and four to six antituberculous drugs have not been found to be predictably active.10'11'22 Recently amikacin, a drug that has not been used to treat infections due to M. fortuitum complex, has been suggested as potentially useful since in one study 50% of strains were inhibited in vitro by this drug.. We are grateful to the laboratories of the Ontario Ministry of Health in Toronto for the identification and antimicrobial sensitivity testing of M. fortuitum, and to Dr. G.A. Sears for referring the patient to us. References

7.

8.

9.

10.

review with a case report. Br I Dermatol 92: 453, 1975 SINGER E, RODDA GM: Nonspecific sensitization to old tuberculin: mycobacteria in water. Tubercie 46: 209, 1965 CHAPMAN JS, BERNARD JS, SPEIGHT M: Isolation of mycobacteria from raw milk. Am Rev Respir Dis 91: 351, 1965 CHAPMAN JS, SPEIGHT M: Isolation of atypical mycobacteria from pasteurized milk. Am Rev Respir Dis 98: 1052, 1968 HAND WL, SANFORD JP: Mycobacteriurn fortuitum - a human pathogen.

Ann Intern Med 73: 971, 1970 11. EDWARDS LB, PALMER CE: Isolation of "atypical" mycobacteria from healthy persons. Am Rev Respir Dis 80: 747, 1959 12. DALINKA MK, HEMMING VG: Atypical mycobacterial osteomyelitis. Report of a case associated with acute lymphoblastic leukemia. I Can Assoc Radiol 22: 173, 1971

13. PHILLIPS 5, LARKIN JC: Atypical pulmonary tuberculosis caused by unclassified mycobacteria. Ann Intern Med 60: 401, 1964 14. CORPE RF, SMITH CE, STERGUS I:

Death due to Mycobacterium fortuiturn. JAMA 177: 262, 1961 15. LAZAR M, NEMET P, BRACHA R, et al:

Mycobacterium fortuitum keratitis. Am I Ophthalmol 78: 530, 1974 16. SLOTNICK IJ, SACKS HJ: Osteomyelitis caused by Mycobacterium fortuitum: report of a case. Am J Clin Pathol

59: 574, 1973 17. KELLY PJ, KARLSON AG, WEED LA, et al: Infection of synovial tissues by mycobacteria other than Mycobac-

terium tuberculosis. J Bone Joint Surg [Am] 49: 1521, 1967 18. ALTMANN G, HoRowITz A, KAPLINSKY N, et al: Prosthetic valve endocarditis due to Mycobacterium chelonei. I Gun Microbiol 1: 531, 1975 19. LASKOWSKI LF, MARR JJ, SPERNOGA JF, et al: Fastidious mycobacteria grown from porcine prosthetic-heartvalve cultures. N Engi I Med 297: 101, 1977

1. FEMBAS KA, SCHNEIRSON SS: Disseminated infection by Mycobacterium fortuitum. J Mt Sinai Hosp NY 36: 375, 1970 2. KATZ M, HULL AR: Probable Mycobacterium fortuitum septicemia: complication of home dialysis (C). Lancet 1: 499, 1971 3. RUNYON EH: Ten mycobacterial pathogens. Tubercie 55: 235, 1974 4. Idem: Anonymous mycobacteria in pulmonary disease. Med Clin North Am 43: 273, 1959

20. LEVY C, CLIRTIN JA, WATKINS A, et al: Mycobacterium chelonei infection

5. OFFER RC, KARL5ON AG, SPITTELL JA JR: Infection caused by Mycc'bac-

23. SANDERS

terium forluitum. Mayo Clin Proc 46: 747, 1971 6. WAnD JM: M. fortuitum and M. chelonei - fast-growing mycobacteria: a

of porcine heart valves (C). N Engi I Med 297: 667, 1977 21. Atypical mycobacteria wound infections - North Carolina, Colorado.

Morbid Mortal Wkly Rep 25: 238, 1976 22. DREISIN RB, SCOGGIN C, DAVIDSON

PT: The pathogenicity of Mycobacterium fortuitum and Mycobacterium chelonei in man: a report of seven cases. Tubercie 57: 49, 1976 WE

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CMA JOURNAL/JULY 22, 1978/VOL. 119 155

Prosthetic valve endocarditis due to Mycobacterium fortuitum.

Prosthetic valve endocarditis due to Mycobacterium fortuitum S.L. NARASIMHAN,* MD; T.W. AUSTIN, MD, FRCP[C] Infection with Mycobacterium fortuitum, a...
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