A rare combination of sites of involvement by Mycobacterium intracellulare in a hemodialysis patient: multifocal synovitis, spondylitis, and multiple skin lesions

Vertebral osteomyelitis caused by non-tuberculous mycobacteria: Predisposing conditions and clinical characteristics of six cases and a review of 63 cases in the literature

Background Several case series have reported on clinical and radiographic characteristics of patients with vertebral osteomyelitis (VO) caused by non-tuberculous mycobacteria (NTM). However, only a few patients were included, and systematic reviews are still lacking. The aim of this study was to update and summarise the pre-disposing conditions, clinical and radiographic characteristics of such cases due to NTM. Methods In this study, a systematic review was conducted of the English-language literature from 1961-2014 to investigate the pre-disposing conditions and characteristics of cases of VO due to NTM. Also, six additional cases diagnosed in the study hospitals were described; these cases are included in an analysis of a total of 69 cases of NTM VO. Results The most common species, regardless of the presence of HIV co-infection, was M. avium Complex followed by M. xenopi. Ten cases with HIV infection had a median CD4 lymphocyte count of 320/mm(3) (range = 41-465/mm(3)) at the time of diagnosis of NTM VO. The VO in the cases with HIV infections occurred at an earlier age and more often involved the thoracic spine than in the cases without HIV infection. Pre-disposing trauma or surgery was reported in 14.5% (10/69) of the cases. A variety of immunosuppressive diseases were observed in 49.3% of the patients, including the 10 with HIV infections and corticosteroids were used in 27.5% of the cases. Surgery was performed in 67.6% and improvement was reported in 80.6%. Conclusion NTM should be considered in immunocompromised patients with indolent VO without confirmation of tuberculosis.

The clinical course of rapidly growing nontuberculous mycobacterial peritoneal dialysis infections in Asians: A case series and literature review

INTRODUCTION

Peritoneal dialysis (PD)-related infections due to rapidly growing nontuberculous mycobacterium (RGNTM) are rare in Asians and have variable clinical outcomes.

METHODS

We analysed retrospectively a series of RGNTM infections in a single-centre multi-ethnic Asian population over a 5-year period. Clinical features, treatment, risk factors and outcomes are discussed.

RESULTS

Ten infections are described. They constituted 3% of all culture-positive exit site infection (ESI) and PD peritonitis. Seventy percent were due to Mycobacterium abscessus (three ESI and four peritonitis). There were two Mycobacterim fortuitum and one Mycobacterium chelonei peritonitis. No specific findings differentiated RGNTM infections from those caused by traditional organisms. Six cases had received prior antibiotics, two being topical gentamicin. Initial routine culture and alcohol acid fast bacillus were negative except for one case of M. abscessus. A confirmatory diagnosis was made a median 9 days post culture. No infection responded to routine antibiotics. Antibiotic resistance was variable but M. abscessus was universally sensitive to clarithromycin. Combined antibiotics based on sensitivity profile were successfully used in 70% of the cases. PD catheter loss was 80%. Three-month mortality was 40% (vs. 8.5% and 12% in non-RGNTM ESI and peritonitis, respectively). This may be related to the cohort high mean Charlson score of 7.5.

CONCLUSION

RGNTM PD infections are commoner in Asians than previously reported. Their early diagnosis requires a high index of suspicion and appropriate treatment started promptly. They are associated with prior antibiotic use and refractory culture-negative infections, delayed diagnosis and lead to significant catheter loss and death.

Clinical manifestations of nontuberculous mycobacteria infections

The isolation of nontuberculous mycobacteria (NTM) from clinical specimens has become very frequent in the last years. Such organisms are typically environmental and poorly pathogenic for humans; they can, however, be responsible for opportunistic diseases in subjects presenting with various predisposing conditions. Pulmonary infections are responsible for the most frequent disease caused by NTM, although the relevance of mycobacterioses involving other parts of the body is increasing. The risk of disseminated infections characterizing immunocompromised patients is well known, and those numbers are steadily rising. The lymph nodes, cutis and soft tissues, as well as bone and joints, are also important targets of NTM infection. The problems concerning the assessment of the clinical significance of NTM, along with a consideration of the more frequent NTM pathologies, are the major objectives of this review.

A cluster of rapidly growing mycobacterial peritoneal dialysis catheter exit-site infections

In this case series, a cluster of 5 consecutive peritoneal dialysis patients with atypical mycobacterial exit-site infections in a single center within 20 months are described. Clinical features, treatment, and outcomes are discussed. Most patients had been treated with prolonged systemic antibiotic therapy for recurrent bacterial exit-site infections in the preceding months, and all had used topical gentamicin ointment for exit-site infection treatment or prophylaxis. It is postulated that this might have predisposed them to atypical mycobacterial exit-site infection as a result of selection pressure on uncommon organisms.

Atypical mycobacterial spondylitis in HIV-negative patients identified by genotyping

Non-tuberculous mycobacterial infections pose a significant diagnostic and therapeutic challenge. We report two cases of such infection of the spine in HIV-negative patients who presented with deformity and neurological deficit. The histopathological features in both specimens were diagnostic of tuberculosis. The isolates were identified as Mycobacterium intracellulare and M. fortuitum by genotyping (MicroSeq 16S rDNA Full Gene assay) and as M. tuberculosis and a mycobacterium other than tuberculosis, respectively, by culture. There is a growing need for molecular diagnostic tools that can differentiate accurately between M. tuberculosis and atypical mycobacteria, especially in regions of the developing world which are experiencing an increase in non-tuberculous mycobacterial infections.

Mycobacterial synovitis caused by slow-growing nonchromogenic species: eighteen cases and a review of the literature

CONTEXT

Slow-growing nonchromogenic mycobacterial species are an infrequent cause of soft tissue infection. Because these organisms are rare, they are not often initially considered in the differential diagnosis of synovitis.

OBJECTIVE

To evaluate the clinical and pathologic characteristics of patients with synovitis resulting from slow-growing nonchromogenic mycobacterial species.

DESIGN

A 20-year retrospective review of records from The Methodist Hospital Microbiology Laboratory identified 18 culture-positive cases of synovitis that resulted from slow-growing nonchromogenic mycobacteria, including 14 caused by Mycobacterium avium complex, 1 caused by Mycobacterium malmoense, 1 caused by Mycobacterium haemophilum, and 2 caused by Mycobacterium nonchromogenicum isolates. In addition, a comprehensive literature search revealed an additional 48 cases of synovitis caused by slow-growing nonchromogenic mycobacteria.

RESULTS

The historic literature described the majority of the 48 patients as previously healthy, elderly individuals with a several-month history of monoarticular pain and swelling in the small joints of the upper extremity. In contrast, the current series demonstrated the probable role of multiple chronic coexisting medical conditions in promoting disease susceptibility. These patients were also unique in their significantly younger age distribution and diversity of infection sites. Histologic examination and direct acid-fast bacteria stains generally did not aid the diagnosis. Amputation was performed in 2 patients because of delayed identification of disease.

CONCLUSIONS

The current series demonstrates that difficult identification and infrequent occurrence cause these organisms to be overlooked by physicians and laboratory personnel. A heightened clinical suspicion for slow-growing nonchromogenic mycobacterial species is necessary when routine culture and histopathologic findings do not readily isolate an organism, or when the patient does not respond to antibiotic and anti-inflammatory treatment.

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.

Vertebral osteomyelitis caused by non-tuberculous mycobacteria

Vertebral osteomyelitis caused by non-tuberculous mycobacteria is a rare disease, with only 31 cases and one nosocomial outbreak reported in the literature (MedLine review between 1965 and December 2003). The clinical features are often indistinguishable from those of pyogenic osteomyelitis. Early diagnosis of such infections is a major challenge because of the slow growth of these microorganisms. No consensus guidelines for the treatment of these infections exist. Prolonged anti-mycobacterial therapy in combination with surgical debridement is recommended.