CLINICAL CHARACTERISTICS AND VISUAL OUTCOMES IN ENDOPHTHALMITIS AFTER KERATOPROSTHESIS IMPLANTATION

PURPOSE

To describe the presentation, microbiology, management, and prognosis of eyes with endophthalmitis after Boston keratoprosthesis implantation.

METHODS

Retrospective case series with history, diagnostics, management, and outcomes data in endophthalmitis after keratoprosthesis implantation presenting to a tertiary center between 2009 and 2020.

RESULTS

Of 137 keratoprosthesis-implanted eyes, 7 eyes of 7 patients (5%) developed endophthalmitis. On presentation, 6 (86%) reported decreased visual acuity, and only 1 (14%) reported pain. Peripheral corneal ulcers were present in 2 eyes (29%). Seidel testing was negative in all cases. Six eyes (86%) had retroprosthetic membranes. One (14%) underwent initial pars plana vitrectomy with mechanical vitreous biopsy, whereas 6 (86%) received a needle vitreous tap-half of which were dry. Organisms were isolated after vitreous tap in two eyes: Streptococcus intermedius and Mycobacterium abscessus. The mean visual acuity preendophthalmitis, at presentation, and at 6 months were 20/267, 20/5,944, and 20/734, respectively. The visual acuity improved 9.08 ± 11.78 Early Treatment Diabetic Retinopathy Study lines from presentation to 6 months. Six-month visual acuity was correlated with preendophthalmitis visual acuity (r = 0.92, P = 0.003) but not presenting visual acuity (P = 0.838).

CONCLUSION

Visual acuity at 6 months is correlated with preendophthalmitis visual acuity, not presenting visual acuity. Endophthalmitis should be considered in the differential diagnosis of painless intraocular inflammation any time after keratoprosthesis implantation, even if Seidel negative.

Mycobacterial fatty acid catabolism is repressed by FdmR to sustain lipogenesis and virulence

Host-derived fatty acids are an important carbon source for pathogenic mycobacteria during infection. How mycobacterial cells regulate the catabolism of fatty acids to serve the pathogenicity, however, remains unknown. Here, we identified a TetR-family transcriptional factor, FdmR, as the key regulator of fatty acid catabolism in the pathogen Mycobacterium marinum by combining use of transcriptomics, chromatin immunoprecipitation followed by sequencing, dynamic 13C-based flux analysis, metabolomics, and lipidomics. An M. marinum mutant deficient in FdmR was severely attenuated in zebrafish larvae and adult zebrafish. The mutant showed defective growth but high substrate consumption on fatty acids. FdmR was identified as a long-chain acyl-coenzyme A (acyl-CoA)-responsive repressor of genes involved in fatty acid degradation and modification. We demonstrated that FdmR functions as a valve to direct the flux of exogenously derived fatty acids away from β-oxidation toward lipid biosynthesis, thereby avoiding the overactive catabolism and accumulation of biologically toxic intermediates. Moreover, we found that FdmR suppresses degradation of long-chain acyl-CoAs endogenously synthesized through the type I fatty acid synthase. By modulating the supply of long-chain acyl-CoAs for lipogenesis, FdmR controls the abundance and chain length of virulence-associated lipids and mycolates and plays an important role in the impermeability of the cell envelope. These results reveal that despite the fact that host-derived fatty acids are used as an important carbon source, overactive catabolism of fatty acids is detrimental to mycobacterial cell growth and pathogenicity. This study thus presents FdmR as a potentially attractive target for chemotherapy.

Influence of intersegmental plane size and segment division methods on preserved lung volume and function after pulmonary segmentectomy

OBJECTIVES

We previously reported that the use of a stapler to divide intersegmental planes did not decrease preserved pulmonary volume or function relative to electrocautery. However, preservation of pulmonary volume or function can be compromised when a stapler is used with larger intersegmental planes. Here, we assessed the correlations between preserved lung volume and pulmonary function after segmentectomy and the size of the intersegmental planes, based on the division method.

METHODS

Intersegmental plane sizes in 56 patients were semi-automatically calculated using image analysis software on computed tomography images. The ratios of the remnant segment and ipsilateral lung volumes to their preoperative values (R-seg and R-ips) and the ratio of the postoperative pulmonary function relative to the predicted value were calculated based on three-dimensional volumetry. Correlations between preserved lung volume and pulmonary function and the intersegmental plane sizes were analyzed according to the division method.

RESULTS

Intersegmental planes were divided by either electrocautery or with a stapler (EC/Mixed) in 21 patients and by stapler alone (ST) in 35 patients. There was no difference in the average size of the intersegmental planes between the two groups. The intersegmental plane size negatively correlated with R-seg in the ST group.

CONCLUSIONS

Using the stapler method, as the size of the intersegmental planes increased, the preserved remnant segmental volume decreased; however, relation between the plane size and preserved pulmonary function was unclear. These findings indicate that stapler use is acceptable even for large intersegmental planes.

Clinical Features of Nontuberculous Mycobacterial Pleurisy: A Review of 12 Cases

Objective The incidence of pulmonary nontuberculous mycobacterial (NTM) infections has increased in recent decades. Nevertheless, NTM pleurisy is still a rare disease. The objective of the present study was to elucidate the clinical features and outcomes of NTM pleurisy. Methods A retrospective study was undertaken of consecutive patients whose pleural effusion culture yielded NTM, from 2002 to 2016 at a respiratory hospital in Japan. The clinical features, treatment, and outcomes of these patients were analyzed. Result The 12 patients with NTM pleurisy were predominantly male, with a median age of 69 years (range, 48-93 years). They included eight patients with a history of smoking and six patients with immunosuppressive comorbidities such as malignancy, diabetes mellitus, and conditions requiring steroid administration. Fibrocavitary disease was the most common radiographic feature of these patients, and Mycobacterium avium complex was the most common pathogen. Pneumothorax was complicated in 11 patients. Surgery was performed on seven patients, in addition to thoracic drainage for the treatment of pleurisy and pneumothorax. Three patients died of respiratory failure. Conclusion Pneumothorax is a frequent complication of NTM pleurisy, often making the condition difficult to treat. Surgery at an appropriate time should therefore considered for refractory cases.

Mycobacterium marinum remains an unrecognized cause of indolent skin infections

We identified 5 patients who had cutaneous lesions with cultures that yielded Mycobacterium marinum. It was discovered that all 5 patients had a home aquarium, and infection was preceded by trauma to the hand. However, the association between the development of the infection and exposure of the trauma site to the aquarium was not initially established until repeated questioning was performed. Skin biopsies or incision and drainage were performed for all patients, and the diagnosis was established by culture of the specimens. The mean time from initial presentation to diagnosis and initiation of appropriate treatment was 91 days (range, 21-245 days). Prolonged therapy for 2 to 6 months was necessary for resolution of the infection.

Clinical characteristics and immunogenetics of BCGosis/BCGitis in Chinese children: a 6 year follow-up study

In this study, the clinical and immunogenetical features in a cohort of Chinese patients with BCGosis/BCGitis were investigated. For the patients with abnormal immunological functions, Sanger sequencing was used to identify the involved genes. There were 74 confirmed cases of BCGosis/BCGitis during 2007–2012. Classified by infected tissues and organs, no cases only had local infection, 39 patients had a regional infection, 21 patients had a distant infection and 14 patients had a disseminated infection. Thirty-two patients (43.2%) had definitive primary immunodeficiency diseases (PID) and chronic granulomatous disease (CGD) is the most common PID (n = 23, accounted for 71.9% of all PID patients). For CGD patients, based on the anti-tuberculosis treatment, administration of rhIFN-γ resulted in better control of BCGosis/BCGitis. The results indicate that PIDs are associated with susceptibility to BCG disease. For children with BCGosis/BCGitis, immune function evaluation is necessary, and IFN-γ treatment for BCGosis/BCGitis patients with CGD is effective.

Emerging aspects of Buruli ulcer

Buruli ulcer, caused by the pathogen Mycobacterium ulcerans, is a major mycobacteriosis that affects people in scattered foci in the third world. It is amongst the most neglected of diseases in terms of primary healthcare strategies. However, this is changing as the World Health Organization launches a number of major global initiatives. Recent progress includes the unraveling of the genetic structure of the pathogen, examination of the mechanisms of virulence and the role of chemotherapy in disease treatment and prevention of recurrence, together with strategies aimed at reducing the economic burdens placed upon healthcare budgets of poorer nations. This review focuses upon the recent developments and the understanding of the disease, with particular focus on potential chemotherapy.

Post-operative sinus formation due to Mycobacterium abscessus: a case report

Mycobacterium abscessus is ubiquitously found rapidly growing mycobacteria. Although it is an uncommon pathogen, it has been known to cause cutaneous infection following inoculation, minor trauma or surgery. This communication reports an immuno-competent patient developing multiple sinuses due to Mycobacterium abscessus in the post- operative period.

Mycobacterium abscessus lung disease in a patient with previous pulmonary tuberculosis

Patients with pre-existing lung damage, such as due to pulmonary tuberculosis (PTB), are susceptible to nontuberculous mycobacteria (NTM) infections. For patients with previous PTB, it is difficult to differentiate NTM lung disease from PTB, especially in tuberculosis (TB) high-burdened countries. Here, we report a case of Mycobacterium abscessus lung disease with a previous history of PTB. The patient underwent a right upper lobe lobectomy due to disappointing treatment response with anti-tuberculosis therapy. However, the disease worsened after the surgery. Five years later, she was diagnosed with M. abscessus lung disease. Successive computed tomography (CT) scans showed the progressing features of M. abscessus lung disease. This patient had multiple micronodules adjacent to the pleura with a positive culture for NTM. Bilateral bronchiectasis without lobar predominance are valuable features for distinguishing M. abscessus lung disease from other mycobacterial lung disease.

Venous catheter-associated bacteremia caused by rapidly growing mycobacteria at a medical center in central Taiwan

BACKGROUND AND PURPOSE

Infections due to rapidly growing mycobacteria (RGM) are increasing worldwide, especially in immunocompromised hosts, but data on the clinical features of patients with RGM bacteremia are limited in Taiwan. This study was performed to determine the features associated with RGM.

METHODS

The medical records of 12 patients with RGM bacteremia admitted to the Changhua Christian Hospital, Changhua, Taiwan, from April 2001 to March 2003 were retrospectively studied. Clinical data were reviewed and antimicrobial susceptibility testing of blood isolates by the agar disk elution method was performed.

RESULTS

RGM bacteremia was caused by Mycobacterium fortuitum in 5 patients, Mycobacterium smegmatis in 3, Mycobacterium flavescens in 2, and Mycobacterium abscessus in 2. There were 5 men and 7 women (age range, 4-75 years). All patients had underlying diseases and all of the infections were associated with an indwelling vascular catheter. The time to onset of bacteremia ranged from 1 to 24 months. Fever (n = 11) was the most common presenting symptom. Susceptibility testing revealed a different antibiogram for each species of RGM. The rate of relapsing bacteremia was significantly higher in patients with delayed catheter removal and for whom the catheter was not removed (6/8; 75%) than in patients with timely catheter removal (0/4; 0%) [p = 0.03].

CONCLUSIONS

RGM bacteremia is rare but should be considered in immunocompromised patients with an indwelling venous catheter and undifferentiated fever. Identifying RGM at the species level and performing susceptibility testing are useful for guiding management. The catheter should be removed as soon as possible.

Visual Recovery FollowingMycobacterium chelonaeEndophthalmitis

Following uncomplicated cataract surgery, a patient receiving etanercept for psoriatic arthritis developed Mycobacterium chelonae endophthalmitis. Vitrectomy, capsulectomy, and intraocular lens removal was followed by intravitreal amikacin, topical gatifloxacin, intravenous imipenem, and oral clarithromycin for six months. The patient achieved a final corrected visual acuity of 20/20. Etanercept has been implicated in the development of numerous, severe granulomatous infections, though not previously with M. chelonae. This represents the first reported case of visual recovery following M. chelonae endophthalmitis.

Bilateral sporotrichoid lymphocutaneous dermatosis in a drug abuser: case report and review of the literature

Bilateral sporotrichoid mycobacterial cutaneous infection is unusual and has been reported in only three cases involving different species and with an unknown route of infection in the literature.We report a case of bilateral sporotrichoid dermatosis in an immunocompetent patient with a history of intravenous heroin injection before development of the skin lesions. Both special stain and culture of biopsy specimen were negative. Finally, Mycobacterium fortuitum was identified by a polymerase chain reaction-based method. The patient responded well to clarithromycin and ciprofloxacin therapy. This case represents an unusual primary cutaneous M. fortuitum infection manifested as bilateral sporotrichoid lesions of the limbs. Review of previous reported cases of bilateral sporotrichoid mycobacterial infection shows different isolated organisms and routes of infection to that found in our case.

[A case of pulmonary Mycobacterium gordonae infection progressed for no therapy]

A 68-year-old woman, who had been healthy until this event, presented with a complaint of productive cough since 2000. She went to a neighboring hospital because of bloody sputum in October 2001. Although chest radiograph showed abnormal findings then, she received only an expectorant and cough remedy. She consulted us complaining of dyspnea on exertion in April 2005. Chest radiograph revealed cavity formation, bronchiectasis and a nodular shadow, and her condition had deteriorated. Microbiologically, acid-fast bacilli were detected three times in the culture of sputum, and Mycobacterium gordonae was identified by the biochemical method. However, this Mycobacterium gordonae could not be identified by the DNA-DNA hybridization method. Our case also probably was considered to be a primary type pulmonary nontuberculous infection because of her clinical course. In addition, we recognized that pulmonary M. gordonae infection also worsens without the therapy.

Buruli ulcer: emerging from obscurity

Buruli ulcer is a skin disease caused by infection with Mycobacterium ulcerans, which produces a potent toxin known as mycolactone, thus distinguishing itself from all other mycobacterial diseases. Mycolactone destroys cells in the subcutis, leading to the development of large ulcers with undermined edges. The genome sequence of M ulcerans has now been published and it transpires that two identical copies of a plasmid carry the genetic code for mycolactone. The mode of transmission of infection remains uncertain, although environmental sources of the organisms are now better understood. Considerable progress has been made in understanding the immune response to M ulcerans and there have been major advances in management of the disease with the introduction of rational antibiotic therapy. We summarise the current understanding of M ulcerans and its relations with human beings.

Clinical significance and epidemiology of non-pigmented rapidly growing mycobacteria in a university hospital

OBJECTIVES

To study the clinical significance and epidemiology of Non-pigmented rapidly growing mycobacteria (NPRGM) during a 13-year period.

METHODS

We performed a retrospective study of patients with isolates of NPRGM to evaluate their clinical significance. We also analyzed the strains using Randomly Amplified Polymorphic DNA (RAPD) analysis to evaluate the relationship between strains.

RESULTS

Between 1990 and 2003, 65 patients had an isolate of NPRGM. Twenty of them were considered significant (19 cases) or doubtful (1 case). Many cases were skin and soft tissue infections. Six cases were foreign-body related. All the patients recovered with antibiotic therapy and removal of the foreign body. All the patients were apparently unrelated, despite 56.9% of the isolates were detected between 1995 and 1997. RAPD analysis was performed on 43 strains, and showed only a cluster of two Mycobacterium chelonae isolates. Both of them were related with contamination of a laboratory reactive, and were considered non-significant.

CONCLUSION

In our hospital, almost one-third of the isolates of NPRGM were significant, being this percentage higher for skin and soft tissue isolates. Patients were cured with antibiotic therapy, but the removal of foreign bodies appeared to be necessary for a good outcome. A minor pseudo-outbreak was detected. No predominant strain was detected.

Non-tuberculous mycobacteria in end stage cystic fibrosis: implications for lung transplantation

BACKGROUND

WC and NS contributed equally. Non-tuberculous mycobacteria (NTM) frequently colonise patients with end stage cystic fibrosis (CF), but its impact on the course of the disease following lung transplantation is unknown.

METHODS

Lung transplant recipients with CF who underwent lung transplantation at our institution between January 1990 and May 2003 (n=146) and CF patients awaiting lung transplantation in May 2003 (n=31) were studied retrospectively.

RESULTS

The prevalence rate of NTM isolated from respiratory cultures in patients with end stage CF referred for lung transplantation was 19.7%, compared with a prevalence rate of 13.7% for NTM isolates in CF lung transplant recipients. The overall prevalence of invasive NTM disease after lung transplantation was low (3.4%) and was predicted most strongly by pre-transplant NTM isolation (p=0.001, Fisher's exact test, odds ratio (OR) 6.13, 95% CI 3.2 to 11.4). This association was restricted to Mycobacterium abscessus (p = 0.005, Fisher's exact test, OR 7.45, 95% CI 2.9 to 16.9). While NTM disease caused significant morbidity in a small number of patients after transplantation, it was successfully treated and did not influence the post-transplant course of the disease.

CONCLUSION

The isolation of NTM before transplantation in CF patients should not be an exclusion criterion for lung transplantation, but it may alert the clinician to patients at risk of recurrence following transplantation.

Systemic suppression of interferon- responses in Buruli ulcer patients resolves after surgical excision of the lesions caused by the extracellular pathogen Mycobacterium ulcerans

Buruli ulcer (BU), caused by Mycobacterium ulcerans, is the third most common mycobacterial infection in immunocompetent humans besides tuberculosis and leprosy. We have compared by ex vivo enzyme-linked immunospot analysis interferon-gamma (IFN-gamma) responses in peripheral blood mononuclear cells (PBMC) from BU patients, household contacts, and individuals living in an adjacent M. ulcerans nonendemic region. PBMC were stimulated with purified protein derivative (PPD) and nonmycobacterial antigens such as reconstituted influenza virus particles and isopentenyl-pyrophosphate. With all three antigens, the number of IFN-gamma spot-forming units was reduced significantly in BU patients compared with the controls from a nonendemic area. This demonstrates for the first time that M. ulcerans infection-associated systemic reduction in IFN-gamma responses is not confined to stimulation with live or dead mycobacteria and their products but extends to other antigens. Interleukin (IL)-12 secretion by PPD-stimulated PBMC was not reduced in BU patients, indicating that reduction in IFN-gamma responses was not caused by diminished IL-12 production. Several months after surgical excision of BU lesions, IFN-gamma responses of BU patients against all antigens used for stimulation recovered significantly, indicating that the measured systemic immunosuppression was not the consequence of a genetic defect in T cell function predisposing for BU but is rather related to the presence of M. ulcerans bacteria.

Nerve damage in Mycobacterium ulcerans-infected mice: probable cause of painlessness in buruli ulcer

Buruli ulcer is an emerging chronic painless skin disease found in the tropics and caused by Mycobacterium ulcerans; however, it remains unknown why the large and deep ulcers associated with this disease remain painless. To answer this question, we examined the pathology of BALB/c mice inoculated in the footpads with M. ulcerans African strain 97-107. On days 54 to 70 after inoculation, extensive dermal ulcers, subcutaneous edema, and numerous acid-fast bacilli were noted at the inoculate region. Nerve invasion occurred in the perineurium and extended to the endoneurium, and some nerve bundles were swollen and massively invaded by acid-fast bacilli. However, Schwann cell invasion, a characteristic of leprosy, was not observed. Vacuolar degeneration of myelin-forming Schwann cells was noted in some nerves which may be induced by mycolactone, a toxic lipid produced by M. ulcerans. Polymerase chain reaction analysis of microdissected nerve tissue sections showed positive amplification of M. ulcerans-specific genomic sequences but not of Mycobacterium leprae-specific sequences. Behavioral tests showed decrease of pain until edematous stage, but markedly ulcerated animals showed ordinary response against stimulation. Our study suggests that the painlessness of the disease may be partly due to intraneural invasion of bacilli. Further studies of nerve invasion in clinical samples are urgently needed.

Disseminated Mycobacterium kansasii infection in an HIV-negative patient presenting with mimicking multiple bone metastases

We report a patient with disseminated Mycobacterium kansasii infection, but with no underlying disease, presenting with mimicking multiple bone metastases with cancer of unknown primary site. Disseminated M. kansasii infection is rare in HIV-negative patients without underlying diseases. This patient had disseminated M. kansasii infection manifested with vertebral osteomyelitis, sacroiliitis, psoas abscess, bone marrow granuloma, liver granuloma, and possible spleen abscesses. The clinical manifestations are described and discussed in details.

Buruli ulcer (M. ulcerans infection): new insights, new hope for disease control

Buruli ulcer is a disease of skin and soft tissue caused by Mycobacterium ulcerans. It can leave affected people scarred and disabled. What are the prospects for disease control?

Murine infection model for Mycobacterium fortuitum

Mycobacterium fortuitum is an atypical, non-tubercular, pathogenic, rapidly growing mycobacteria. As very little is known about its virulence determinants, the absence of an animal infection model was always sorely felt. A reliable and reproducible murine infection model has been developed in which non-replicating persistence of 10(5) CFU/g tissue in kidney was observed when a standardised dosage inoculum of 5x10(7) CFU was injected intravenously. The tissue bacillary load was determined at regular intervals (10, 25, 45 and 60 days post-inoculation) in different organs, viz., kidney, spleen, lung and liver. Histopathology of kidney revealed tissue damage and granuloma-like formations which appear to be part of the host's effort to combat the infection. As IFN-gamma is known to trigger antimycobacterial effects of murine macrophages, IFN-gamma was assayed to determine the correlation between host protective measures and bacillary load in kidney. Fifteen days after infection, the level of IFN-gamma secreted by CD4+ and CD8+ T lymphocytes was high, concomitant with high tissue bacillary load, while the level sharply declined as the number of bacilli in kidney decreased 45 days post-inoculation. The invasion and proliferation of M. fortuitum ATCC 6841, when incubated with non-phagocytic (recombination activating genes (RAG) murine kidney) and phagocytic (murine peritoneal macrophages) cell lines, was assessed. M. fortuitum did not invade RAG murine kidney cell line, while the bacilli infected and proliferated freely inside murine macrophages. In conclusion, we present a reproducible murine infection model that sustains a persistent infection, the progression of which correlates meaningfully with host protective response.

Pacemaker infection due to Mycobacterium fortuitum

Pacemaker infection with Mycobacterium fortuitum has not been reported previously. We describe a case of pacemaker generator pocket infection and intravascular lead endocarditis due to Mycobacterium fortuitum. The entire pacing system was removed and the patient was treated successfully with a multidrug regimen for a total of 6 months.

Mycobacterium marinum strains can be divided into two distinct types based on genetic diversity and virulence

Mycobacterium marinum causes a systemic tuberculosis-like disease in a large number of poikilothermic animals and is used as a model for mycobacterial pathogenesis. In the present study, we infected zebra fish (Danio rerio) with different strains of M. marinum to determine the variation in pathogenicity. Depending on the M. marinum isolate, the fish developed an acute or chronic disease. Acute disease was characterized by uncontrolled growth of the pathogen and death of all animals within 16 days, whereas chronic disease was characterized by granuloma formation in different organs and survival of the animals for at least 4 to 8 weeks. Genetic analysis of the isolates by amplified fragment length polymorphism showed that M. marinum strains could be divided in two clusters. Cluster I contained predominantly strains isolated from humans with fish tank granuloma, whereas the majority of the cluster II strains were isolated from poikilothermic species. Acute disease progression was noted only with strains belonging to cluster I, whereas all chronic-disease-causing isolates belonged to cluster II. This difference in virulence was also observed in vitro: cluster I isolate Mma20 was able to infect and survive more efficiently in the human macrophage THP-1 and the carp leukocyte CLC cell lines than was the cluster II isolate Mma11. We conclude that strain characteristics play an important role in the pathogenicity of M. marinum. In addition, the correlation between genetic variation and host origin suggests that cluster I isolates are more pathogenic for humans.

Mycobacterium ulcerans disease (Buruli ulcer) in rural hospital, Southern Benin, 1997-2001

Data from 1,700 patients living in southern Benin were collected at the Centre Sanitaire et Nutritionnel Gbemoten, Zagnanado, Benin, from 1997 through 2001. In the Zou region in 1999, Buruli ulcer (BU) had a higher detection rate (21.5/100,000) than leprosy (13.4/100,000) and tuberculosis (20.0/100,000). More than 13% of the patients had osteomyelitis. Delay in seeking treatment declined from 4 months in 1989 to 1 month in 2001, and median hospitalization time decreased from 9 months in 1989 to 1 month in 2001. This reduction is attributed, in part, to implementing an international cooperation program, creating a national BU program, and making advances in patient care.

Development of a questionnaire assessing Buruli ulcer-induced functional limitation

Buruli ulcer, a disease with long-term consequences, is emerging in west Africa. Thus, a functional limitation scoring system is needed to assess its nature and severity. A list of daily activities was developed for this disease. Following treatment of Buruli ulcer, persons in Benin (n = 47) and Ghana (n = 41) were investigated. Nineteen items were identified with good internal consistency. Participants (median age = 14 years) could not perform 23% of their daily activities. Twenty-nine participants did not have any functional limitation. The average limitation score was 31% in Benin and 15% in Ghana (P = 0.006). The mean limitation score in participants without visible contractures (n = 65) was 13%, whereas patients with visible contractures (n = 20) or an amputation (n = 3) had a score of more than 50%. Validity and reliability should be further analyzed to optimize the scale for use in individual evaluation, as an end point in intervention trials, and in planning of resources needed for the care of patients with functional limitations.

Infections with rapidly growing mycobacteria: report of 20 cases

OBJECTIVES

A series of cases infected with rapidly growing mycobacteria was studied to determine the spectrum of disease, antimicrobial susceptibility, treatment, and outcome.

METHODS

The cases identified as infections with rapidly growing mycobacteria in Ramathibodi Hospital from January 1993 to December 1999 were retrospectively studied.

RESULTS

Most of the cases had no underlying disease. Only two cases were HIV-infected patients. The presenting clinical features were lymphadenitis (seven cases), skin and/or subcutaneous abscess (seven cases), localized eye infection (four cases), pulmonary infection (one case), and chronic otitis media (one case). Four of seven cases with lymphadenitis had Sweet's syndrome, and one had psoriasis as an associated skin manifestation. Anemia was present in five cases, and improved with treatment of the primary disease. The organisms were Mycobacterium chelonae/abscessus group (17 cases) and Mycobacterium fortuitum group (three cases). Susceptibility patterns of the organisms showed susceptibility to amikacin, netilmicin, and imipenem. M. fortuitum group was susceptible to more antibiotics than M. chelonae/abscessus group. The clinical responses corresponded to the antimicrobial susceptibility. Combinations of two or more drugs were used for the medical treatment. Surgical resection was performed where possible, to reduce the load of the organism, especially in cases with very resistant organisms.

CONCLUSIONS

Infections with rapidly growing mycobacteria can occur in apparently normal hosts. The clinical syndrome is variable. The pathology is nonspecific. Clinical responses varied, but seemed to correlate with the in vitro susceptibility result. More studies are needed to enable us to deal with this infection effectively.

Epidemiological, clinical, and prognostic differences between the diseases caused by Mycobacterium kansasii and Mycobacterium tuberculosis in patients infected with human immunodeficiency virus: a multicenter study

A multicenter, comparative study was performed to determine the epidemiological, clinical, and prognostic differences between the diseases caused by Mycobacterium tuberculosis and Mycobacterium kansasii in human immunodeficiency virus (HIV)-infected patients. From 1 January 1995 through 31 December 1999, 25 HIV-infected patients received diagnoses of M. kansasii infection, and another 75 were selected as control subjects from among patients who had M. tuberculosis infection. Variables associated with M. tuberculosis disease in the multivariate analysis were previous intravenous drug use (odds ratio [OR], 8; 95% confidence interval [CI], 1.5-41.4) and interstitial radiologic pattern (OR, 12.7; 95% CI, 1.7-94.3). Variables associated with M. kansasii were previous diagnosis of acquired immunodeficiency syndrome (OR, 15.8; 95% CI, 4.2-59.6) and concomitant opportunistic infections (OR, 14.2; 95% CI, 2-105.7). Clinical and radiologic features were similar for both groups, but epidemiological characteristics and prognosis were different. M. kansasii disease was associated more closely with level of immunosuppression and progression of HIV infection than was disease caused by M. tuberculosis.

Fish tank exposure and cutaneous infections due to Mycobacterium marinum: tuberculin skin testing, treatment, and prevention

In the present study, 8 patients with soft tissue infection due to Mycobacterium marinum are described, and contemporary data on treatment are reviewed. Six patients had positive cultures, all patients had cutaneous exposure to fish tanks, 7 had sporotrichoid lesions, and 2 had deep infection. All 7 tested patients had tuberculin skin test reactions > or =10 mm. Six patients with disease limited to the skin were successfully treated with 2-drug combination therapy, including clarithromycin, ethambutol, and rifampin. Optimal treatment should include 2 drugs for 1-2 months after resolution of lesions, typically 3-4 months in total. Deeper infections may require more prolonged treatment and surgical debridement. Positive tuberculin reactions may be due to infection with M. marinum. Persons with open skin lesions or immunosuppression should avoid cutaneous contact with fish tanks.

Assessment of functional limitations caused by Mycobacterium ulcerans infection: towards a Buruli ulcer functional limitation score

The purpose of this study of treated Buruli ulcer patients in Ghana was to identify and assess late sequelae of treated Buruli ulcer using a goniometer, and to develop a scoring system for functional limitations. Of 78 patients, 58% (n = 45) had a reduction in the range of motion of one or more joints: 30% (n = 23) had one or more functional limitations of the leg and 21% (n = 16) of the arm; 49% (n = 38) had a functional limitation. Of all patients with affected knees, the predicted average extent of limitation was 63%. In patients with affected ankles, limitation was 78% on average; in those with elbow involvement, this was 76% on average, and in wrists involved, 65%. All of the hands involved were markedly restricted. We propose a simplified and functional scoring system that should be tested for validation in a second patient sample, and, if properly validated and adjusted, can be used in future intervention trials.

Infection and disease caused by environmental mycobacteria

Many species of mycobacteria that normally live as environmental saprophytes, the environmental mycobacteria (EM), are opportunist causes of disease in humans and animals. Many, but not all, cases are associated with some form of immune deficiency. An increasing number of species and clinical presentations are being described, and advances are being made in the understanding of the underlying predisposing factors. In recent years, four aspects of EM disease have become particularly relevant to human health: (1) the high prevalence of EM disease in patients with AIDS; (2) the emergence of Buruli ulcer, an ulcerative skin disease caused by Mycobacterium ulcerans, as the third most prevalent mycobacterial disease; (3) the effect of infection by EM on the immune responses to BCG vaccination and on the course and outcome of tuberculosis and leprosy; (4) the controversy over the involvement of mycobacteria, notably M. avium subspecies paratuberculosis, in human inflammatory bowel disease. These aspects change the status of EM from mere curiosities to important direct, indirect, and putative causes of serious and increasingly common human disease.

Susceptibility to development of Mycobacterium ulcerans disease: review of possible risk factors

Mycobacterium ulcerans disease, also known as Buruli ulcer (BU), is a disease of subcutaneous fat tissue. BU is prevalent in riverine and swamp areas of the tropical zone in Africa, Asia and South America, and a few scattered foci in Australia. The mode of transmission of M. ulcerans has not been fully elucidated, but inoculation into the subcutaneous tissues probably occurs through penetrating skin trauma. BU has not been linked with HIV infection. Antimycobacterial drug treatment is ineffective, and treatment is surgical. Patients eventually develop scars and contractures, with resulting disabilities, and the disease imposes a large burden on affected populations. The incidence of BU has dramatically increased in West African countries over the last decade. There is an urgent need for research into host and environmental risk factors for BU in order to develop effective strategies to combat this disease. We review possible genetic host susceptibility factors for BU that are relevant in other mycobacterial diseases: natural resistance-associated macrophage protein-1 (NRAMP-1), HLA-DR, vitamin D3 receptor, mannose binding protein, interferon-gamma (IFN-gamma) receptor, tumour necrosis factor alpha (TNF-alpha), interleukin (IL)-1 alpha, 1 beta and their receptor antagonists; and IL-12. Schistosoma haematobium infection is highly endemic in many BU foci in West Africa, with a striking increase in transmission after river dams were constructed. This observation, and the observations from interaction of schistosomiasis and tuberculosis, have fueled our hypothesis that schistosomiasis is a risk factor for BU by driving the host immune response towards a predominantly Th-2 pattern, away from a Th-1 preponderant protection against mycobacterial infection. If the latter hypothesis is confirmed, enhanced schistosomiasis control should impact on BU.

Nontuberculous mycobacteria

The nontuberculous mycobacteria are for the most part ubiquitous environmental organisms that only rarely cause disease in humans. Therefore, the normal host defense against these organisms must be quite robust, as exposure is universal and disease is rare. The organisms that are most commonly encountered in clinical practice, Mycobacterium avium, M. intracellulare, M. kansasii, M. fortuitum, M. abscessus, and M. chelonae, are frequently found in water sources and soil. These organisms share significant structural and biochemical similarities with their more pathogenic relative, M. tuberculosis (MTB). Because they are of significantly lower pathogenicity than MTB, patients with abnormal susceptibility to these infections should include those with defects that may be identifiable. Study of these patients should lead to determination of the mechanisms underlying resistance to these organisms, which in turn are likely to be highly informative regarding host defense against these infections and their more virulent relative MTB. Furthermore, recognition of host factors that permit infection with nontuberculous mycobacteria in otherwise normal hosts will identify pathways that can be targeted for therapeutic intervention. Thus, the search for genetic and acquired susceptibility to nontuberculous mycobacteria is also a search for susceptibility factors for MTB as well as an opportunity to recognize endogenous pathways that can be exploited therapeutically.

Superoxide production in phagocytes obtained from Mycobacterium marinum-stimulated goldfish (Carassius auratus) that were exposed to copper

OBJECTIVE

To investigate the effects of copper exposure and recovery from copper toxicosis on the nonspecific immune response in Mycobacterium marinum-inoculated goldfish.

ANIMALS

Goldfish (Carassius auratus) with a mean weight of 33.5 g.

PROCEDURE

Superoxide (O2-) production was measured in fish 2 to 6 weeks after injection with phosphate-buffered saline (PBS) solution or M marinum (10(2) to 10(7) colony-forming units [CFU]/fish). Then, paired groups of fish were injected with PBS solution or 10(4) CFU of M marinum and exposed to copper (100 microg/L) for 7 days or for 4 days with 3 days of recovery. One paired group not exposed 14 days later to copper served as control fish. Phagocyte production of O2-was measured by use of the nitroblue tetrazolium reduction assay. Inflammation and bacterial colony counts were determined by use of routine histologic and microbiologic procedures.

RESULTS

Superoxide production achieved a maximal response 2 to 4 weeks after M marinum inoculation. Compared with control fish, O2- production increased in the groups exposed to copper but then decreased in the exposed groups that were allowed to recover. Superoxide response and peritoneal inflammation were greater in M marinum-inoculated groups than in non-inoculated groups.

CONCLUSIONS

Copper exposure and inoculation with M marinum increased O2- production, whereas recovery after exposure decreased O2- production, even in fish that were immunostimulated by M marinum.

CLINICAL RELEVANCE

When the antimicrobial oxidative response is suppressed after copper exposure, steps should be taken to avoid imposing additional stress and minimize the possibility of resurgent or secondary pathogenic infections.

Pathogenicity of Mycobacterium fortuitum and Mycobacterium smegmatis to goldfish, Carassius auratus

Despite the ubiquitous presence of atypical mycobacteria in the environment and the potential risk of infection in humans and animals, the pathogenesis of diseases caused by infection with atypical mycobacteria has been poorly characterized. In this study, goldfish, Carassius auratus were infected either with the rapidly growing fish pathogen, Mycobacterium fortuitum or with another rapidly growing mycobacteria, Mycobacterium smegmatis. Bacterial persistence and pathological host response to mycobacterial infection in the goldfish are described. Mycobacteria were recovered from a high percentage of inoculated fish that developed a characteristic chronic granulomatous response similar to that associated with natural mycobacterial infection. Both M. fortuitum and M. smegmatis were pathogenic to fish. Fish infected with M. smegmatis ATCC 19420 showed the highest level of giant cell recruitment compared to fish inoculated with M. smegmatis mc(2)155 and M. fortuitum. Of the three strains of mycobacteria examined, M. smegmatis ATCC 19420 was the most virulent strain to goldfish followed by M. fortuitum and M. smegmatis mc(2)155, respectively.

[Clinical analysis of 96 cases with pulmonary disease caused by nontuberculous mycobacteria]

OBJECTIVE

To study the clinical characteristics of nontuberculous mycobacteria (NTM) pulmonary disease.

METHODS

Ninety-six out of 173 cases with NTM pulmonary disease diagnosed through identification of mycobacterium strains isolated from 5,592 sputum acid-fast staining positive cases from 1981-1996 were selected, and a retrospective analysis was made.

RESULTS

According to Runyon classification, there were 14 cases with M. kansasii and 1 with M. marinum in type I, 4 with M. scrofulsceum in type II, 23 with M. intracellulare or M. avium in type III, 24 with M. chelonae and 30 with M. fortuitumin in type IV. Cases whose courses of disease were more than 10 years accounted for 31%. Main clinical symptoms included cough (78%), expectoration (71%), haemoptysis (58%) and fever (26%). Fifty-seven percent cases in X-ray chest film were seen lesions bilaterally, 42% in one side, 27% in the right and 15% in the left. One percent showed no obvious lesion in X-ray chest film. Excluding one case with incomplete data, the total resistance rate of NTM was 96% in other 95 cases, 93% in type I, 50%, 100% and 100% in type II, III, IV respectively. After antituberculous chemotherapy, sputum negative conversion was seen in 14 of 15 cases with type I NTM, 6 of 23 with type III and 14 of 54 with type IV, while definite data in 4 cases with type II were not available.

CONCLUSIONS

NTM pulmonary disease is characterized by long course of disease, nonspecific symptoms, high resistance rate and unsatisfactory therapeutic efficacy.

Emergence of a unique group of necrotizing mycobacterial diseases

Although most diseases due to pathogenic mycobacteria are caused by Mycobacterium tuberculosis, several other mycobacterial diseases-caused by M. ulcerans (Buruli ulcer), M. marinum, and M. haemophilum-have begun to emerge. We review the emergence of diseases caused by these three pathogens in the United States and around the world in the last decade. We examine the pathophysiologic similarities of the diseases (all three cause necrotizing skin lesions) and common reservoirs of infection (stagnant or slow-flowing water). Examination of the histologic and pathogenic characteristics of these mycobacteria suggests differences in the modes of transmission and pathogenesis, though no singular mechanism for either characteristic has been definitively described for any of these mycobacteria.

Mycobacterium kansasii osteomyelitis presenting as a solitary lytic lesion of the ulna: fine-needle aspiration findings and morphologic comparison with other mycobacteria

A 35-yr-old woman, with acquired immunodeficiency syndrome, presented with right arm pain, erythema, and swelling. A lytic lesion of the ulna was found by radiograph. Ultrasonic and fluoroscopic guided fine-needle aspiration (FNA) yielded a neutrophilic and histiocytic exudate admixed with abundant long, bacillary forms that appeared as negative images on Papanicolaou stain and as very coarsely beaded acid-fast bacilli, resembling candy canes, on Kinyoun stain. These morphologic features permitted a preliminary diagnosis of mycobacteriosis, possibly of M. kansasii (MK) etiology. Appropriate therapy was initiated and resulted in not only marked symptomatic improvement of osteomyelitis and cellulitis, but resolution of chronic pulmonary infiltrates, presumed to be caused by fibrosis. Culture confirmed MK infection 3 wk after FNA. MK is one of the few mycobacteria that has a sufficiently characteristic morphology to permit presumptive diagnosis by smear. Culture, however, still remains the definitive method of speciation.

Mycobacterium marinum wrist arthritis: local and systematic dissemination caused by concomitant immunosuppressive therapy

The diagnostic difficulties and the potential serious course of Mycobacterium marinum synovitis are illustrated in a patient in whom treatment with local steroid injections and immunosuppressive therapy resulted in local destruction of the wrist and systemic reactions. Healing was achieved after correct medical and surgical treatment was initiated.