Skin disease and nontuberculous atypical mycobacteria

Painful Purulent Nodules Caused by Mycobacterium at Site of Lipodissolve Injections

ABSTRACT

"Lipodissolve" (LD) is a non-FDA-approved solution of phosphatidylcholine in deoxycholate that was developed around 2004. A study of its safety reported minor and uncommon side effects including pain, tender nodules, pigmentary alterations, and ulceration at the site of injection. We present a 53-year-old woman who received LD injections bilaterally to her proximal arms. One week later, she developed painful nodules at each injection site. She was treated with a 10-day course of trimethoprim/sulfamethoxazole without improvement. An incisional biopsy was performed and showed deep dermal suppurative inflammation with numerous neutrophils and granulomas. Stains for bacteria, fungus, and acid-fast organisms were negative. Cultures for acid-fast bacilli grew Mycobacterium abscessus, sensitive to amikacin and clarithromycin. The patient was subsequently treated with intravenous amikacin, azithromycin, and bedaquiline with symptom resolution. Investigation revealed 3 similar infections linked to LD injections originating from the same physician's office. The most common organism implicated in injection infections is Staphylococcus aureus. Infections at injection sites caused by atypical mycobacteria have been reported to occur after tattooing, other types of injections, and implants. Of atypical mycobacteria, M. abscessus accounts for the greatest number of postinjection or iatrogenic infections. Common antitubercular drugs are not effective for treating atypical mycobacteria, making species identification and sensitivity testing imperative for treatment. This case highlights an unusual infection caused by cosmetic injections of LD, previously reported to be associated with minimal side effects, and the importance of examination for acid-fast bacilli and follow-up with culture, even in the absence of organisms identified on stained sections.

Cutaneous Infections Due to Nontuberculosis Mycobacterium: Recognition and Management

Nontuberculous mycobacteria (NTM) are a diverse group of organisms that are ubiquitous in the environment, and the incidence of cutaneous infections due to NTM has been steadily increasing. Cutaneous infections due to NTM can be difficult to diagnose, due to their wide spectrum of clinical presentations and histopathological findings that are often nonspecific. A variety of modalities including tissue culture and polymerase chain reaction (PCR) assays may be necessary to identify the organism. Treatment can also be challenging, as it can depend on multiple factors, including the causative organism, the patient's immunological status, and the extent of disease involvement. In this review, we discuss the common presentations of cutaneous NTM infections, diagnostic tools, and treatment recommendations. A multi-disciplinary approach that involves good communication between the clinician, the histopathologist, the microbiologist, and infectious disease specialists can help lead to successful diagnosis and management.

Amputation of a finger in a patient with multidrug-resistant Mycobacterium marinum skin infection

Mycobacterium marinum is the etiologic agent of fish tank granuloma. The clinical course is usually benign: spontaneous healing is possible within weeks or months. However, fish tank granuloma is sometimes resistant to several antibiotics. We report a case of M. marinum infection of a finger in a 73-year-old cook. The disease was resistant to a number of antibiotics and required the amputation. The history of this patient testifies that M. marinum can be resistant to several antibiotics and that skin infections can be sometimes so severe as to require the amputation of a finger.

Fish Tank Granuloma – a Case Report

Swimming-pool granuloma and fish tank granuloma refer to the infections caused by Mycobacterium marinum. After having been discovered in salt water fish in Philadelphia Aquarium and described in 1926, this skin infection was first reported in humans in 1951. It developed in people who had swum in contaminated swimming pools. M. marinum is a non-tuberculous, atypical mycobacterium, which is found on plants, soil and fish in freshwater and salt water worldwide. Humans become infected usually after trauma and contact with an aquatic environment. Infection is limited to the skin and usually occurs in healthy individuals, but in immunocompromised patients the infection may disseminate or spread to the subcutis and bone. The lesions usually appear as solitary nodules or plaques that may lead to suppurative ulcers after 2-3 weeks of incubation. Occasionally, there may be sporotrichoid spread along lymphatics. Its diagnosis is frequently delayed, probably because the infection is very rare and a history of aquatic exposure, which is present in the majority of cases, is often overlooked. Common misdiagnoses include fungal and parasitic infection, cellulitis, verrucous tuberculosis of the skin, gout, rheumatoid arthritis, a foreign body and a skin tumour. We present a case of a 39-year-old Caucasian male with a 12-month history of a single erythematous tender nodule on the right dorsal aspect of the right hand. Histopathological examination revealed longstanding suppurated granulomatous inflammation. The infection was not responsive to several courses of antibiotics until we introduced doxycycline capsules as monotherapy which led to complete remission after 5 months.

Clinical and histopathological features of cutaneous nontuberculous mycobacterial infection: a review of 13 cases

BACKGROUND

The incidence of cutaneous nontuberculous mycobacterial (NTM) infection has increased in recent decades because of widespread use of immunosuppressive therapy and better detection methods. The histopathology of cutaneous NTM infection is not pathognomic and the organisms are slow and difficult to culture, making diagnosis challenging.

METHODS

We reviewed the clinical and histopathological features of 13 cases of cutaneous NTM infection, and performed panmycobacterial polymerase chain reaction (PCR) on the paraffin blocks.

RESULTS

The immunocompetent patients presented with localized lesions on the extremities, whereas the immunocompromised patients presented with disseminated cutaneous lesions. The histopathology in immunocompetent patients was characterized by pseudoepitheliomatous epidermal hyperplasia, intraepithelial abscesses, transepidermal elimination and dermal granulomatous inflammation accompanied by necrosis and suppuration. The immunocompromised patients showed suppurative inflammation with little granuloma formation and numerous acid-fast bacilli. Paraffin block PCR was positive in 4 of 13 cases (31%), whereas culture was positive in 11 of 13 cases (85%).

CONCLUSION

The aforementioned histological features should help in diagnosing cutaneous NTM infection when combined with clinical and microbiological correlation. In our study, we did not find paraffin block PCR to be superior to conventional culture in detecting cutaneous NTM infection.

Mycobacterium abscessus Infection After Facial Injection With Autologous Fat: A Case Report

We report a case of Mycobacterium abscessus infection in a 29-year-old woman after facial injection with autologous fat. Nineteen months previously, she received a facial surgery of autologous fat injection with the fat harvested from her inner thigh. On examination, she had multiple painful and fluctuant abscesses associated with local pyrexia in her bilateral temporal and lower orbital regions. A B ultrasound revealed multiple fat liquefaction in her bilateral temporal and lower orbital regions. The acid-fast bacilli culture and polymerase chain reaction sequencing confirmed M. abscessus infection. She was treated with moxifloxacin, clarithromycin, and ethambutol for 12 months, and finally the symptoms subsided. To avoid infection after fat graft, aseptic technique as well as standard operation of the fat harvest and process should be strictly enforced. In cases of persistent infection, or invalid cases treated with conventional antibiotic therapy, nontuberculous mycobacteria should be suspected, and a polymerase chain reaction sequencing as well as a drug sensitivity test should be carried out.

The Buruli Ulcer

Buruli ulcer (BU) is caused by Mycobacterium ulcerans and can manifest as a simple nodule or as aggressive skin ulcers leading to debilitating osteoarthritis or limb deformity. The disease is more prevalent in those living in remote rural areas, especially in children younger than 15 years. The exact mode of transmission is possibly through traumatic skin lesions contaminated by M ulcerans. IS2404 polymerase chain reaction from ulcer swabs or biopsies is a rapid method for confirmation of BU. In coendemic countries, HIV infection complicates the progression of BU, leading to rapidly spreading osteomyelitis. Treatment is principally medical, with antitubercular drugs, and surgery is utilized for complicated disease. Because of ineffective vaccination, primary prevention is the best option for control of the disease.

Pediatric Cutaneous Nontuberculous Mycobacterium Infections in Singapore

BACKGROUND

Nontuberculous mycobacterium (NTM) infections are rare in children, with limited published studies. The course of the disease can be variable and there are no accepted treatment guidelines for the management of NTM infections in children.

OBJECTIVE

To review a cohort of pediatric patients admitted to a tertiary pediatric hospital in Singapore for cutaneous NTM infections.

METHODS

A retrospective review was performed of all children admitted to KK Women's and Children's Hospital with cutaneous NTM infections from 2002 to 2012.

RESULTS

Sixty-seven patients with positive NTM cultures from various body sites were identified. Eight of the 67 patients (11.9%) presented with cutaneous NTM without evidence of systemic involvement. The mean age at diagnosis for these eight patients was 10 years (range 5-21 yrs). Mycobacterium abscessus was the most common NTM isolated (five patients), followed by Mycobacterium hemophilium (two patients) and Mycobacterium kansasii (one patient). Most patients presented with isolated skin abscesses. Two patients were immunocompromised. Six patients required multidrug antibiotic treatment for a median duration of 5.5 months (range 3-17 mos). The median follow-up duration was 8.5 months (range 2 wks-29 mos).

CONCLUSION

Although the incidence of cutaneous NTM is rare, the diagnosis should be considered in patients presenting with chronic wounds. Most patients require treatment with multidrug antibiotic therapy, although uncomplicated abscesses can be treated with surgical incision and drainage alone.

Nontuberculous mycobacterial infection after fractionated CO(2) laser resurfacing

Nontuberculous mycobacteria are increasingly associated with cutaneous infections after cosmetic procedures. Fractionated CO2 resurfacing, a widely used technique for photorejuvenation, has been associated with a more favorable side effect profile than alternative procedures. We describe 2 cases of nontuberculous mycobacterial infection after treatment with a fractionated CO2 laser at a private clinic. Densely distributed erythematous papules and pustules developed within the treated area within 2 weeks of the laser procedure. Diagnosis was confirmed by histologic analysis and culture. Both infections responded to a 4-month course of a multidrug regimen. An environmental investigation of the clinic was performed, but no source of infection was found. The case isolates differed from each other and from isolates obtained from the clinic, suggesting that the infection was acquired by postprocedure exposure. Papules and pustules after fractionated CO2 resurfacing should raise the suspicion of nontuberculous mycobacterial infection.

Reactive and infective dermatoses associated with adult-onset immunodeficiency due to anti-interferon-gamma autoantibody: Sweet's syndrome and beyond

Immunodeficiency due to anti-interferon-gamma autoantibody (anti-IFN-γ autoAb) is an emerging adult-onset immunodeficiency syndrome predominantly found in Southeast Asians. It is associated with severe or disseminated infections caused by non-tuberculous mycobacteria (NTM) and other opportunistic pathogens. We describe 3 patients with anti-IFN-γ autoAb who developed reactive and infective dermatoses, and thoroughly review the existing literature on dermatoses associated with the immunodeficiency syndrome. Case 1 developed Sweet's syndrome associated with Mycobacterium chelonae lymphadenitis and penicilliosis. Case 2 suffered from multiple episodes of lobular panniculitis during recurrent infections by NTM, Penicillium marneffei and Burkholderia pseudomallei. Both cases responded to immunomodulating agents including corticosteroid and non-steroidal anti-inflammatory drugs. Case 3 had direct skin invasion by M. chelonae and responded to prolonged anti-mycobacterial therapy. A novel working algorithm is proposed for the diagnosis and treatment of these patients who may be encountered by the dermatologist and histopathologist in clinical practice.

Mycobacterium fortuitum skin infection as a complication of anabolic steroids: a rare case report

Mycobacterium fortuitum is a rare cause of recurrent skin abscesses in an immunocompetent person. We report the case of a 37-year-old man presenting with multiple recurrent non-healing skin abscesses. Culture of the abscess wall yielded growth of M fortuitum. In our case, we highlight the association of anabolic steroids with non-tuberculous mycobacterial skin abscesses that fail to resolve despite repeated drainage.

Histopathological spectrum of cutaneous tuberculosis and non-tuberculous mycobacterial infections

The non-specific clinical findings and variable histopathological features of cutaneous tuberculosis and non-tuberculous mycobacterial infections often make it difficult to establish a diagnosis and initiate appropriate therapy. We investigated 25 patients diagnosed with mycobacterial infections of the skin in Hanyang University Hospital between 2001 and 2011. Skin biopsy specimens were re-evaluated by various histopathological criteria and molecular studies. To identify the mycobacteria, we performed staining for acid-fast bacilli and also completed polymerase chain reaction analysis. The non-tuberculous mycobacterium species were identified by genetic sequencing of formalin-fixed, paraffin-embedded tissues. Immunocompromised status was more frequent in non-tuberculous mycobacterial infections than in tuberculosis (p = 0.017) while disease duration was longer in tuberculosis (p = 0.026). Microscopically, neutrophil infiltration, interstitial granuloma, small vessel proliferation and increased numbers of bacilli were found to be associated with non-tuberculous mycobacterial infections (all p < 0.05). In contrast, giant cells, plasma cells, tuberculoid granulomas and necrosis were associated with tuberculosis (all p < 0.05). There were no species-specific histopathological findings in non-tuberculous mycobacterial infections. The significant histopathological differences between cutaneous tuberculous and non-tuberculous mycobacterial infections are helpful in considering differential diagnoses. In addition, molecular techniques together with clinico-pathological findings may assist in making accurate diagnoses of cutaneous non-tuberculous mycobacterial infections.

Mycobacterium fortuitum abdominal wall abscesses following liposuction

We describe here a case of abdominal abscesses due to Mycobacterium fortuitum following liposuction. The abscesses developed three months after the procedure and diagnosis was delayed for five months. The clues for diagnosis were persistent pus discharge in spite of broad spectrum antibiotics and failure to grow any organisms on routine culture. This condition has been rarely reported; however, the increasing number of liposuction procedures done and awareness among physicians will probably result in the identification of more cases. Combination antibiotic therapy with surgical drainage in more extensive diseases is essential for cure.

Refractory Hand Ulceration: A Case of Chronic Ulceration and Sporotrichoid Spread in a Fish Tank Hobbyist following Mycobacterium marinum Infection

We report the case of a 35-year-old man with a chronic ulceration of the hand in whom an infection with Mycobacterium marinum was diagnosed. Clarithromycin and doxycycline were prescribed, resulting in a slow resolution of the ulceration. M. marinum is a nontuberculous mycobacterium that causes skin lesions such as nodules, ulcerations, and sporotrichoid spread, but may also be responsible for osteoarticular lesions. In this case report, we discuss the clinical characteristics of this condition, as well as its diagnostic methods and treatments.

Non-tuberculous mycobacterial infections of the skin: a retrospective study of 29 cases

The incidence of infections caused by non-tuberculous mycobacteria has increased in recent years, due to a rise in dermatological procedures and a greater prevalence of immunosuppression in the general population. This study investigated the clinical and microbiological findings of non-tuberculous mycobacterial skin infections. The study population included 29 patients from whom non-tuberculous mycobacteria were cultured after isolation from skin biopsy materials, cutaneous abscesses or exudates. Clinical, microbiological and epidemiological data were collected from each patient. Eight patients were immunocompromised while 21 were not. Precipitating factors such as acupuncture, filler injection, surgical procedures and other traumatic events preceded infection in 13 (including 11 normal hosts and two immunocompromised hosts) of the 29 patients. Multiple skin lesions were present in eight patients (including three normal hosts and five immunocompromised hosts). In eight patients (including four immunocompromised hosts), symptoms were accompanied by tenosynovitis, osteomyelitis and myositis. Mycobacterium abscessus was isolated from nine patients, Mycobacterium fortuitum was isolated from nine patients, Mycobacterium chelonae was isolated from six patients, Mycobacterium marinum was isolated from two patients, a Mycobacterium avium complex member was isolated from two patients, and Mycobacterium haemophilum was isolated from one patient. Ten of the 24 cases caused by rapidly growing organisms (i.e. M. chelonae, M. abscessus and M. fortuitum groups) were precipitated by skin injuries such as acupuncture, filler infection and other medical procedures. Increases in skin medical procedures, including both acupuncture and esthetic interventions, explain the increasing incidence of these organisms. Immunocompromised patients tended to develop multiple skin lesions and deep tissue infections.

IFN-gamma-dependent activation of macrophages during experimental infections by Mycobacterium ulcerans is impaired by the toxin mycolactone

Buruli ulcer, caused by Mycobacterium ulcerans infections, is a necrotizing skin disease whose pathogenesis is associated with the exotoxin mycolactone. Despite the relevance of this emergent disease, little is known on the immune response against the pathogen. Following the recent demonstration of an intramacrophage growth phase for M. ulcerans, we investigated the biological relevance of IFN-gamma and the antimycobacterial mechanisms activated by this cytokine in M. ulcerans-infected macrophages. Three M. ulcerans strains were tested: 5114 (mutant mycolactone-negative, avirulent strain); 94-1327 (intermediate virulence); and 98-912 (high virulence). We show in this study that IFN-gamma is expressed in mouse-infected tissues and that IFN-gamma-deficient mice display increased susceptibility to infection with strains 5114 and, to a lesser extent, 94-1327, but not with the highly virulent strain. Accordingly, IFN-gamma-activated cultured macrophages controlled the proliferation of the avirulent and the intermediate virulent strains. Addition of mycolactone purified from strain 98-912 to cultures of IFN-gamma-activated macrophages infected with the mycolactone-negative strain led to a dose-dependent inhibition of the IFN-gamma-induced protective mechanisms, involving phagosome maturation/acidification and increased NO production, therefore resulting in increased bacterial burdens. Our findings suggest that the protection mediated by IFN-gamma in M. ulcerans-infected macrophages is impaired by the local buildup of mycolactone.

Myocardial abscess and bacteremia complicating Mycobacterium fortuitum pacemaker infection: case report and review of the literature

A case of pacemaker infection complicated by bacteremia and myocardial abscess caused by Mycobacterium fortuitum is reported and 9 other cases of pacemaker infection associated with rapidly growing mycobacteria are reviewed. Most cases developed within 6 months from implantation suggesting nosocomial acquisition. Wound discharge, fever, and pain at generator site were the most common presenting features. At presentation they had a median duration of symptoms of 34 days. Concomitant bacteremia was present in half of the cases. Antibiotics therapy and removal of the pacemaker system were needed to achieve cure in the majority of cases. Clarithromycin and fluoroquinolones were the most commonly used antibiotics.

Disseminated cutaneous Mycobacterium chelonae infection with multidrug resistance in a patient with panuveitis

We report the case of a 43-year-old immunosuppressed woman who presented with cellulitis of the lower limbs and multiple widespread subcutaneous nodules in a sporotrichoid distribution. Microbiological findings from skin biopsy confirmed Mycobacterium chelonae infection.

Nontuberculous mycobacterial infections of the skin: A retrospective study of 25 cases

BACKGROUND

Absence of a pathognomonic clinical picture and variable histologic findings often delay diagnosis of nontuberculous mycobacteria (NTM)-induced cutaneous infections, and antimicrobial therapy varies.

OBJECTIVE

We sought to investigate the clinical, microbiologic, and pathological findings of cutaneous NTM infections and response to different treatments.

METHODS

Records of patients with NTM infections of the skin confirmed by positive cultures or histologic findings were reviewed. Clinical, microbiologic, and epidemiologic data were collected and skin biopsy specimens were reassessed.

RESULTS

The series included 25 cases, one diagnosed by histology and 24 by positive culture: 16 cases with Mycobacterium marinum, 3 of atypical Mycobacterium without species identification, and one each with M chelonae, M xenopi, M abscessus, M gordonae, and M fortuitum. One of 16 patients with M marinum developed tenosynovitis. Mean interval between clinical presentation and diagnosis was 7.1 months (range: 1-27.3 months). All isolates analyzed for antimicrobial susceptibility pattern were sensitive to clarithromycin.

LIMITATIONS

Limitations include methods of case collection, retrospective study, and relatively small number of patients.

CONCLUSIONS

Diagnosis of NTM should be confirmed by histology and bacteriology studies of tissue cultures. Strong clinical suggestion of M marinum infection warrants initial empirical treatment to prevent progression to deep infection. The recommended treatment as indicated by the results of the in vitro susceptibility and clinical response is clarithromycin.

Evidence for an intramacrophage growth phase of Mycobacterium ulcerans

Mycobacterium ulcerans is the etiologic agent of Buruli ulcer (BU), an emerging tropical skin disease. Virulent M. ulcerans secretes mycolactone, a cytotoxic exotoxin with a key pathogenic role. M. ulcerans in biopsy specimens has been described as an extracellular bacillus. In vitro assays have suggested a mycolactone-induced inhibition of M. ulcerans uptake by macrophages in which its proliferation has not been demonstrated. Therefore, and uniquely for a mycobacterium, M. ulcerans has been classified as an extracellular pathogen. In specimens from patients and in mouse footpad lesions, extracellular bacilli were concentrated in central necrotic acellular areas; however, we found bacilli within macrophages in surrounding inflammatory infiltrates. We demonstrated that mycolactone-producing M. ulcerans isolates are efficiently phagocytosed by murine macrophages, indicating that the extracellular location of M. ulcerans is not a result of inhibition of phagocytosis. Additionally, we found that M. ulcerans multiplies inside cultured mouse macrophages when low multiplicities of infection are used to prevent early mycolactone-associated cytotoxicity. Following the proliferation phase within macrophages, M. ulcerans induces the lysis of the infected host cells, becoming extracellular. Our data show that M. ulcerans, like M. tuberculosis, is an intracellular parasite with phases of intramacrophage and extracellular multiplication. The occurrence of an intramacrophage phase is in accordance with the development of cell-mediated and delayed-type hypersensitivity responses in BU patients.

Cytokine mRNA expression in Mycobacterium ulcerans-infected human skin and correlation with local inflammatory response

Cytokine mRNA expression in biopsies of Mycobacterium ulcerans-infected human tissue was investigated using real-time PCR, and the findings were correlated with the clinical stages of disease and histopathologies. A broad range of cytokine mRNAs were detected in 16 early nodules and 28 late-stage ulcers, including those for the Th1 cytokines tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma) and the Th2 cytokine interleukin 10 (IL-10). IFN-gamma was strongly expressed in both nodules and ulcers, suggesting that a Th1 response begins early in the disease. There was a significantly higher expression of IL-8 and other proinflammatory cytokines in results from 32 biopsies with neutrophilia than in those from 12 biopsies without acute inflammation. Ten tissue samples containing granulomas showed high mRNA expression for IFN-gamma, IL-1beta, IL-12p35, IL-12p40, IL-15, and TNF-alpha relative to 34 tissue samples without granulomas. These results suggest that the human immune response to M. ulcerans is similar to that seen with some other mycobacteria despite the presence of the toxin mycolactone in the tissues.

Atypical Mycobacterium furunculosis occurring after pedicures

Mycobacterium fortuitum complex are rapidly-growing nontuberculous mycobacteria found ubiquitously in the environment including, water, soil, dust, and biofilms. M fortuitum has been reported to cause skin and soft-tissue infections in association with nail salon footbath use during pedicures. Four cases of M fortuitum complex furunculosis are reported that occurred after pedicures in the Cincinnati, Ohio/Northern Kentucky area. Dermatologists and clinicians should consider mycobacterial infections from the M fortuitum complex when patients present with nonhealing furuncles on the lower legs and should inquire about recent pedicures. Early recognition and institution of appropriate therapy are critical. Public health measures should be explored to protect against such infections, given the recent popularity of the nail care industry.

CC chemokine receptor (CCR)-2 prevents arthritis development following infection by Mycobacterium avium

The host factors that influence autoimmune arthritides such as rheumatoid arthritis have not been fully elucidated. We previously found that genetic inactivation of CC chemokine receptor 2 (CCR2) in the arthritis-prone DBA/1j mouse strain significantly increases the susceptibility of this strain to autoimmune arthritis induced by immunization with collagen type II (CII) and complete Freund's adjuvant (CFA). Here, we show that following intradermal infection with Mycobacterium avium, a similar arthritis phenotype was detected in Ccr2-null mice in the DBA/1j, but not in the BALB/c background. The failure to develop arthritis in Ccr2-null BALB/c mice occurred in the face of high bacterial burdens and low interferon gamma (IFNgamma) production. By contrast, Ccr2-null DBA/1j mice had low bacterial burdens, produced normal amounts of IFNgamma, and had high titers of autoantibodies against CII. Thus, the Ccr2-null state in an arthritic-prone genetic background leads to increased arthritis susceptibility following infectious (M. avium) and noninfectious (CII/CFA) challenges. Because CCR2 serves as a negative regulator of murine arthritis, caution might need to be exercised while testing CCR2 blockers in human arthritis or other diseases. These findings also indicate that Ccr2-null DBA/1j mice might serve as a valuable model system to uncover the immunological determinants of arthritis and to test novel antiarthritic agents.

Infection with Mycobacterium ulcerans induces persistent inflammatory responses in mice

Buruli ulcer (BU) is a devastating, necrotizing, tropical skin disease caused by infections with Mycobacterium ulcerans. In contrast to other mycobacterioses, BU has been associated with minimal or absent inflammation. However, here we show that in the mouse M. ulcerans induces persistent inflammatory responses with virulence-dependent patterns. Mycolactone-positive, cytotoxic strains are virulent for mice and multiply progressively, inducing both early and persistent acute inflammatory responses. The cytotoxicity of these strains leads to progressive destruction of the inflammatory infiltrates by postapoptotic secondary necrosis, generating necrotic acellular areas with extracellular bacilli released by the lysis of infected phagocytes. The necrotic areas, always surrounded by acute inflammatory infiltrates, expand through the progressive invasion of healthy tissues around the initial necrotic lesions by bacteria and by newly recruited acute inflammatory cells. Our observations show that the lack of inflammatory infiltrates in the extensive areas of necrosis seen in advanced infections results from the destruction of continuously produced inflammatory infiltrates and not from M. ulcerans-induced local or systemic immunosuppression. Whether this is the mechanism behind the predominance of minimal or absent inflammatory responses in BU biopsies remains to be elucidated.

Clinical patterns of cutaneous nontuberculous mycobacterial infections

BACKGROUND

Cutaneous nontuberculous mycobacterial infections result from external inoculation, spread of a deeper infection, or haematogenous spread of a disseminated infection. There are two species-specific infections (fish-tank or swimming-pool granuloma, due to Mycobacterium marinum, and Buruli ulcer, caused by M. ulcerans). Most infections, however, produce a nonspecific clinical picture.

OBJECTIVES

To define clinical patterns of cutaneous disease in nontuberculous mycobacterial infections.

METHODS

Fifty-one patients with cutaneous nontuberculous mycobacterial infections were reviewed. Clinical and histopathological features of normal hosts and immunosuppressed patients were compared. Two subgroups of immunosuppressed patients were distinguished: patients with cutaneous infection and patients with a disseminated infection and cutaneous involvement.

RESULTS

In immunosuppressed patients the number of lesions was significantly higher. Abscesses and ulceration were also more frequently observed. Different species were found in normal hosts and immunosuppressed patients. Several clinical patterns of cutaneous infection were defined: lymphocutaneous or sporotrichoid lesions; nonlymphocutaneous lesions at the site of trauma; folliculitis and furunculosis involving the lower extremities; disseminated lesions on the extremities in immunosuppressed patients. Two patterns were observed in patients with a disseminated infection: localized cutaneous lesions and disseminated cutaneous and mucosal lesions.

CONCLUSIONS

Cutaneous manifestations of nontuberculous mycobacterial infections may be classified according to criteria such as cutaneous lesions and immune status.

Subcutaneous Infection with Mycobacteriumabscessus in a Renal Transplant Recipient

Transplant recipients show a high incidence of infections, often with atypical manifestations mainly because of drug-related immunosuppression. Mycobacterial infections can be life-threatening in immunosuppressed patients due to the risk of dissemination. There have been only few reports of cutaneous infections with Mycobacterium abscessus among immunosuppressed patients. We present a rare case with a sporotrichoid skin infection with M. abscessus in a renal recipient. The value of immunohistochemical detection of mycobacteria using an anti-BCG antibody in the diagnostic work-up skin biopsies is demonstrated. Long-term antibiotic treatment resulted in complete remission, although recurrences with atypical presentation were observed.