Case of Mycobacterium marinum Infection with Unusual Patterns of Susceptibility to Commonly Used Antibiotics

Abstract

Mycobacterium marinum, found commonly in salt water and freshwater, is the causative agent of disease in many species of fish and occasionally in humans. MICs to most antimicrobial agents are relatively low. Susceptibility testing is not routinely performed, and single-drug therapy is used for the treatment of most infections. Here, we report an infection caused by a drug-resistant M. marinum strain in an otherwise healthy patient. CASE REPORTA 45-year-old healthy man sought medical care following a fish hook injury to the right third metacarpal area. Over the course of 10 to 14 days, he developed a tender lump over the right third metacarpal joint, which became increasingly tender to the touch. Otherwise, the patient was in good health, and his past medical history was unremarkable. On physical examination, he appeared well and was afebrile and in no acute distress. The examination of the hand was pertinent for no gross peritendinous fluid collection, tenosynovial thickening, or evidence of cellulitis. A magnetic resonance image (MRI) with and without contrast was obtained, indicating soft tissue swelling over the distal third metacarpal and proximal phalanx, with no evidence of osteomyelitis or abscess. Given the patient's history and recent fish hook injury, the possibility of an atypical mycobacterial infection was raised. An incisional biopsy was performed, and a small full-thickness ellipse of the inflamed skin was removed and sent to the laboratory for microscopy and culture. Additional skin samples were sent to pathology for histology and special stains. The patient was treated with doxycycline (100 mg orally [p.o.], twice daily) and topical mupirocin.Two weeks later, the patient returned for a follow-up visit. Physical examination revealed a residual, patchy, erythematous rash over the right third metacarpal, a small circular patchy rash over the right fourth metacarpal, and a similar rash over the dorsum of the right hand. These findings were clinically consistent with and interpreted as psoriasis. Examination of his trunk and extremities showed no other patches or lesions similar to those present on the right hand. He was advised to continue the doxycycline and follow up in 2 to 3 weeks. The patient was also given a prescription for 15 g of 0.05% fluocinonide (Lidex) ointment and instructed to use it sparingly on the affected area.Initial cultures of the wound material grew an acid-fast bacillus after 18 days of incubation at 37°C using LowensteinJensen medium. The patient returned 2 weeks after the prior visit and presented with a persistent, nonhealing, irregular erythematous nodule with a diminished plaque and an individual punctate elevation of the skin. He was advised to continue the doxycycline twice daily, and the fluocinonide was discontinued. Susceptibility testing on this isolate was requested and performed by a large reference laboratory according to established protocols using broth microdilution and a quality control strain of M. avium (ATCC 700898) susceptible to both doxycycline (MIC, 2...

A survey of antimicrobial resistance in Enterobacteriaceae isolated from the Chesapeake Bay and adjacent upper tributaries

“…We previously described unusual resistance patterns in bacteria implicated in wound infections in patients seen within our hospital network (Parrish, Luethke, Dionne, Carroll, & Riedel, ). The infections were related to recreational activities on the Chesapeake Bay waters.…”

Necrotizing Soft Tissue Infection Occurring after Exposure toMycobacterium marinum

“…Currently, there is no consensus on definitive treatment regimens due to paucity of controlled trials [3]. However, most isolates are resistant to isoniazid and pyrazinamide and produce β -lactamase [3, 10]. …”

“…Several studies have shown effective eradication with a single antibiotic for uncomplicated cases, although most experts recommend 2-drug therapy [3, 10]. Clarithromycin alone, or in combination with ethambutol or rifampin, is preferred for superficial infections [2, 10].…”

“…Clarithromycin alone, or in combination with ethambutol or rifampin, is preferred for superficial infections [2, 10]. Minocycline, doxycycline, or trimethoprim-sulfamethoxazole can be substituted for clarithromycin [10].…”

“…Clarithromycin alone, or in combination with ethambutol or rifampin, is preferred for superficial infections [2, 10]. Minocycline, doxycycline, or trimethoprim-sulfamethoxazole can be substituted for clarithromycin [10]. Duration of therapy ranges from 6 to 20 weeks, with some experts recommending continuation of treatment 1-2 months or longer, after resolution of skin lesions, as described in our case [3].…”