Clinical manifestations, diagnosis, and treatment of Mycobacterium haemophilum infections

Highly Reduced Genome of the New Species Mycobacterium uberis, the Causative Agent of Nodular Thelitis and Tuberculoid Scrotitis in Livestock and a Close Relative of the Leprosy Bacilli

Nodular thelitis is a chronic enzootic infection affecting dairy cows and goats. The causative agent was recently shown to be related to the leprosy-causing bacilli Mycobacterium leprae and Mycobacterium lepromatosis In this study, the genome of this pathogen was sequenced and analyzed. Phylogenomic analyses confirmed that the pathogen present in nodular thelitis and tuberculoid scrotitis is a distinct species related to the leprosy bacilli and Mycobacterium haemophilum Because the pathogen was originally isolated from a bovine udder, it was named "Mycobacterium uberis" The genome of "M. uberis" is only 3.12 Mb in length, which represents the smallest mycobacterial genome identified so far but which is close to that of leprosy bacilli in size. The genome contains 1,759 protein-coding genes and 1,081 pseudogenes, indicative of extensive reductive evolution and likely the reason that M. uberis cannot be grown axenically. The pseudogenization and genome reduction in M. uberis seem to have been to some extent independent from the results determined for the genomes of the leprosy bacilli.IMPORTANCE M. uberis is an emerging skin pathogen in dairy animals. Its genome underwent massive reduction and gene decay, leading to a minimal set of genes required for an obligatory intracellular lifestyle, which highly resembles the evolution of the leprosy agents M. leprae and M. lepromatosis The genomic similarity between M. uberis and the leprosy bacilli can help in identifying key virulence factors of these closely related species or in identifying genes responsible for the distinct differences between thelitis or scrotitis and leprosy with respect to clinical manifestations. Specific DNA markers can now be developed for quick detection of this pathogen.

Atypical Mycobacterial Infections of the Upper Extremity

Atypical mycobacterial infections of upper extremity synovial-lined structures are often misdiagnosed and unrecognized. Despite an increasing incidence, lack of physician awareness of these pathogens may result in considerable delay in diagnosis and management, potentially leading to permanent disability. The authors conducted a literature review and analyzed 31 cases of penetrating atypical mycobacterial infection to better understand the clinical characteristics and to evaluate their posttreatment complication rate compared with available literature. Medical records for culture-positive cases of tenosynovial or intra-articular atypical mycobacterial infections of the upper extremity that were treated were retrospectively reviewed. Treatment outcomes were analyzed against published case reviews and case series. Thirty-one cases of penetrating atypical mycobacterial infection were identified. Mycobacterium marinum (n=11) was the most common organism and was associated with aquatic exposure. Twenty-eight cases received empiric treatment, 17 of which received contraindicated treatment. Patients saw an average of 5 physicians prior to receiving an accurate diagnosis, and the mean time to diagnosis was 10 months. All cases received antibiotic treatment in addition to surgical management. Twenty cases (68%) failed treatment outcomes. Delay in diagnosis and inappropriate management of atypical mycobacterial infections may lead to a treatment failure rate that is higher than what has been reported in the literature. Mycobacterium avium and M fortuitum had significantly higher failure rates than other organisms. A high index of suspicion is required to make a diagnosis and prevent residual disability. [Orthopedics. 2018; 41(3):e383-e388.].

Late-onset postoperative Mycobacterium haemophilum endophthalmitis masquerading as inflammatory uveitis: a case report

Background

Although atypical mycobacteria had been increasingly found in various ocular infections in the past decades, a slow-growing Mycobacterium haemophilum (M. haemophilum) was scarcely reported. Similar to tuberculous infection, the presentation can masquerade as low-grade granulomatous intraocular inflammation with partial response to corticosteroids. Besides, the special requirements for culture make this pathogen difficult to diagnose. The study aims to report the clinical presentation and notify the awareness of NTM endophthalmitis among clinicians. This is the first case report of late-onset, postoperative M. haemophilum endophthalmitis in the literature.

Case presentation

A 66-year-old man with non-insulin-dependent diabetes mellitus (NIDDM) manifested chronic granulomatous inflammation in the left eye after multiple glaucoma surgeries. With a diagnosis of noninfectious panuveitis, he was treated with systemic corticosteroids. The inflammation initially responded to therapy although it subsequently worsened and became purulent endophthalmitis. The vitreous cultures grew M. haemophilum. Intraocular and systemic antimicrobial treatments were administered early, but the patient eventually turned blind.

Conclusions

M. haemophilum endophthalmitis is a rare but serious intraocular complication leading to loss of vision or eyeball. Awareness of atypical mycobacterial infections is necessary especially in patients with impaired immune function, previous intraocular surgery, and corticosteroid resistance. Proper laboratory investigations and treatments should be performed. However, due to the rarity of the disease, the development of guidelines for its investigation and therapy is still challenging.

Other Slow-Growing Nontuberculous Mycobacteria

The list of clinically important slow-growing nontuberculous mycobacteria (NTM) continues to expand as new species are identified and older ones are found to be pathogenic. Based on pigment production, the strains may be classified as photochromogenic, scotochromogenic, or unpigmented. Some of these organisms are not newly discovered but have heretofore been considered virtually nonpathogenic. Previously, many were regarded as contaminants when isolated from clinical specimens. Ubiquitous in nature, many NTM have been isolated from groundwater or tap water, soil, house dust, domestic and wild animals, and birds. Most infections result from inhalation or direct inoculation from environmental sources. They are not spread from person to person. The infections may be localized or disseminated. In most cases, the optimal regimen or duration of therapy has not been firmly established. The results of in vitro susceptibility testing may be used to select a therapeutic regimen. Many experts recommend clarithromycin with companion drugs such as rifampin and ethambutol for most, but not all, slowly growing species. Aminoglycosides, clofazimine, fluoroquinolones, linezolid, pyrazinamide, or trimethoprim-sulfamethoxazole also may be effective against some strains. Immunocompetent patients with clinically significant infections with NTM usually should receive 18 to 24 months of therapy. Infected immunocompromised patients, particularly those with disseminated infection, probably should receive therapy as long as their immune systems remain impaired. Some of the species discussed include Mycobacterium alsiense, M. celatum, M. gordonae, M. haemophilum, M. kyorinense, M. malmoense, M. simiae complex, M. szulgai, M. terrae complex, M. ulcerans, and M. xenopi.

Fifteen-year clinical experience with Mycobacterium haemophilum at the Mayo Clinic: A case series

Mycobacterium haemophilum is an uncommonly encountered acid-fast staining bacillus (AFB) that can cause a broad range of infections. We describe a tertiary care center's experience with M. haemophilum infections identified from 2000 to 2015. Ten adult patients were identified with M. haemophilum infections, and most had immunocompromising conditions. M. haemophilum presented in one of two syndromes: a peripheral cutaneous infection presenting with skin nodularity and local invasion, and a cervicofacial infection involving regional lymph nodes. Duration of therapy was variable (0–18 months) and was dependent on the underlying syndrome and immunological status of the patient. Treatment responses were favorable in all patients. During therapy, three patients developed culture-negative aseptic cutaneous lesions, consistent with immunologic reconstitution inflammatory syndrome (IRIS); we postulate that such reactions may not be uncommon with select M. haemophilum infections.

Disseminated Mycobacterium haemophilum infection in a renal transplant recipient

Opportunistic infections are a major concern in renal and transplant medicine. We present the case of a renal transplant recipient with a generalised Mycobacterium haemophilum infection after an increase in immunosuppressive therapy and treatment with a tumour necrosis factor-α (TNF-α) inhibitor. Infection involved skin and soft tissue, joints and bones, as well as the renal transplant with an interstitial nephritis. Rapid diagnosis using PCR and DNA sequencing allowed early appropriate treatment. Triple antibiotic therapy and reduction in immunosuppression resulted in a slow but sustained recovery. Immunosuppression causes severe opportunistic infections. TNF-α inhibitors are very effective and well tolerated but have an increased susceptibility to infections with mycobacteria. Mycobacterial infections represent a significant clinical risk to transplant recipients because of their aggressive clinical course and the need for complex toxic antibiotic treatments. In these patients, M. haemophilum is a cause of skin infections.

16S-23S Internal Transcribed Spacer Region PCR and Sequencer-Based Capillary Gel Electrophoresis has Potential as an Alternative to High Performance Liquid Chromatography for Identification of Slowly Growing Nontuberculous Mycobacteria

Accurate identification of slowly growing nontuberculous mycobacteria (SG-NTM) of clinical significance remains problematic. This study evaluated a novel method of SG-NTM identification by amplification of the mycobacterial 16S-23S rRNA internal transcribed spacer (ITS) region followed by resolution of amplified fragments by sequencer-based capillary gel electrophoresis (SCGE). Fourteen American Type Culture Collection (ATCC) strains and 103 clinical/environmental isolates (total n = 24 species) of SG-NTM were included. Identification was compared with that achieved by high performance liquid chromatography (HPLC), in-house PCR and 16S/ITS sequencing. Isolates of all species yielded a SCGE profile comprising a single fragment length (or peak) except for M. scrofulaceum (two peaks). SCGE peaks of ATCC strains were distinct except for peak overlap between Mycobacterium kansasii and M. marinum. Of clinical/environmental strains, unique peaks were seen for 7/17 (41%) species (M. haemophilum, M. kubicae, M. lentiflavum, M. terrae, M. kansasii, M. asiaticum and M. triplex); 3/17 (18%) species were identified by HPLC. There were five SCGE fragment length types (I–V) each of M. avium, M. intracellulare and M. gordonae. Overlap of fragment lengths was seen between M. marinum and M. ulcerans; for M. gordonae SCGE type III and M. paragordonae; M. avium SCGE types III and IV, and M. intracellulare SCGE type I; M. chimaera, M. parascrofulaceum and M. intracellulare SCGE types III and IV; M. branderi and M. avium type V; and M. vulneris and M. intracellulare type V. The ITS-SCGE method was able to provide the first line rapid and reproducible species identification/screening of SG-NTM and was more discriminatory than HPLC.

Mycobacterium haemophilum infection in a juvenile leatherback sea turtle (Dermochelys coriacea)

Mycobacteriosis is infrequently reported in free-ranging sea turtles. Nontuberculous Mycobacterium haemophilum was identified as the causative agent of disseminated mycobacteriosis in a juvenile leatherback turtle (Dermochelys coriacea) that was found stranded on the Atlantic coast of Florida. Disseminated granulomatous inflammation was identified histologically, most notably affecting the nervous system. Identification of mycobacterial infection was based on cytologic, molecular, histologic, and microbiologic methods. Among stranded sea turtles received for diagnostic evaluation from the Atlantic and Gulf of Mexico coasts of the United States between 2004 and 2015, the diagnosis of mycobacteriosis was overrepresented in stranded oceanic-phase juveniles compared with larger size classes, which suggests potential differences in susceptibility or exposure among different life phases in this region. We describe M. haemophilum in a sea turtle, which contributes to the knowledge of diseases of small juvenile sea turtles, an especially cryptic life phase of the leatherback turtle.

Disseminated Mycobacterium haemophilum skeletal disease in a patient with interferon-gamma deficiency

Disseminated non-tuberculous mycobacterial (NTM) infection is rare in immunocompetent adults. Anti-interferon-gamma (IFN-γ) autoantibodies have recently been associated with NTM infections, particularly in patients of Asian ethnicity. We describe a case of disseminated Mycobacterium haemophilum skeletal infection due to anti IFN-γ autoantibodies in a 71-year-old Cambodian man. He responded to a combination of anti-mycobacterial antibiotics without requirement for immunomodulator therapy. Testing for acquired IFN-γ deficiency due to IFN-γ autoantibodies should be considered when standard tests for immunodeficiency are negative in patients with unusual or severe opportunistic infections, including NTM.

Isolation of Nontuberculous Mycobacteria from the Environment of Ghanian Communities Where Buruli Ulcer Is Endemic

This study aimed to isolate nontuberculous mycobacterial species from environmental samples obtained from some selected communities in Ghana. To optimize decontamination, spiked environmental samples were used to evaluate four decontamination solutions and supplemented media, after which the best decontamination solution and media were used for the actual analysis. The isolates obtained were identified on the basis of specific genetic sequences, including heat shock protein 65, IS2404, IS2606, rpoB, and the ketoreductase gene, as needed. Among the methods evaluated, decontamination with 1 M NaOH followed by 5% oxalic acid gave the highest rate of recovery of mycobacteria (50.0%) and the lowest rate of contamination (15.6%). The cultivation medium that supported the highest rate of recovery of mycobacteria was polymyxin B-amphotericin B-nalidixic acid-trimethoprim-azlocillin-supplemented medium (34.4%), followed by isoniazid-supplemented medium (28.1%). Among the 139 samples cultivated in the main analysis, 58 (41.7%) yielded mycobacterial growth, 70 (50.4%) had no growth, and 11 (7.9%) had all inoculated tubes contaminated. A total of 25 different mycobacterial species were identified. Fifteen species (60%) were slowly growing (e.g., Mycobacterium ulcerans, Mycobacterium avium, Mycobacterium mantenii, and Mycobacterium malmoense), and 10 (40%) were rapidly growing (e.g., Mycobacterium chelonae, Mycobacterium fortuitum, and Mycobacterium abscessus). The occurrence of mycobacterial species in the various environmental samples analyzed was as follows: soil, 16 species (43.2%); vegetation, 14 species (38.0%); water, 3 species (8.0%); moss, 2 species (5.4%); snail, 1 species (2.7%); fungi, 1 species (2.7%). This study is the first to report on the isolation of M. ulcerans and other medically relevant nontuberculous mycobacteria from different environmental sources in Ghana.

IMPORTANCE

Diseases caused by mycobacterial species other than those that cause tuberculosis and leprosy are increasing. Control is difficult because the current understanding of how the organisms are spread and where they live in the environment is limited, although this information is needed to design preventive measures. Growing these organisms from the environment is also difficult, because the culture medium becomes overgrown with other bacteria that also live in the environment, such as in soil and water. We aimed to improve the methods for growing these organisms from environmental sources, such as soil and water samples, for better understanding of important mycobacterial ecology.

Pulmonary Disease Caused by Non-Tuberculous Mycobacteria

Non-tuberculous mycobacteria (NTM) include more than 160 ubiquitous, environmental, acid-fast-staining bacterial species, some of which may cause disease in humans. Chronic pulmonary infection is the most common clinical manifestation. Although patients suffering from chronic lung diseases are particularly susceptible to NTM pulmonary disease, many affected patients have no apparent risk factors. Host and pathogen factors leading to NTM pulmonary disease are not well understood and preventive therapies are lacking. NTM isolation and pulmonary disease are reported to rise in frequency in Europe as well as in other parts of the world. Differentiation between contamination, infection, and disease remains challenging. Treatment of NTM pulmonary disease is arduous, lengthy, and costly. Correlations between results of in vitro antibiotic susceptibility testing and clinical treatment outcomes are only evident for the Mycobacterium avium complex, M. kansasii, and some rapidly growing mycobacteria. We describe the epidemiology of NTM pulmonary disease as well as emerging NTM pathogens and their geographical distribution in non-cystic fibrosis patients in Europe. We also review recent innovations for the diagnosis of NTM pulmonary disease, summarize treatment recommendations, and identify future research priorities to improve the management of patients affected by NTM pulmonary disease.

Similar presentation of cervical lymphadenitis of different etiology in two siblings

Here, we report chronic suppurating submandibular swelling occurring in two siblings, with one case caused by nontuberculous mycobacteria and the other caused by Bartonella henselae. These two infections share a similar clinical presentation, but the treatment modalities differed.

Facial Skin Lesions in Children Caused by Nontuberculous Mycobacteria

BACKGROUND

Nontuberculous mycobacteria rarely cause facial skin lesions in immunocompetent children.

AIM

I describe the clinical features and treatment of nontuberculous mycobacteria facial lesions.

MATERIALS AND METHODS

The diagnosis of a facial nontuberculous mycobacteria infection was established using polymerase chain reaction.

RESULTS

Of 286 children with confirmed nontuberculous mycobacteria infection, 14 (4.9%; median age 50 mos, range 9-156 mos; 5 [36%] male, 9 [64%] female) had nontuberculous mycobacteria facial skin lesions. Six (43%) had lesions on the cheek and five (36%) in the medial eye corner. Polymerase chain reaction results confirmed the presence of Mycobacterium haemophilum in eight patients (57%) and Mycobacterium avium in six patients (43%). The facial lesions were treated using a combination of clarithromycin and rifabutin for 12 weeks, with a median healing time of 4 months.

CONCLUSION

Nontuberculous mycobacteria facial lesions are rare in immunocompetent children. The diagnosis requires a high index of suspicion. Nonsurgical treatment is preferable, because surgical excision of the cutaneous lesions might lead to undesirable visible facial scars.

The Complete Genome Sequence of the Emerging Pathogen Mycobacterium haemophilum Explains Its Unique Culture Requirements

Mycobacterium haemophilum is an emerging pathogen associated with a variety of clinical syndromes, most commonly skin infections in immunocompromised individuals. M. haemophilum exhibits a unique requirement for iron supplementation to support its growth in culture, but the basis for this property and how it may shape pathogenesis is unclear. Using a combination of Illumina, PacBio, and Sanger sequencing, the complete genome sequence of M. haemophilum was determined. Guided by this sequence, experiments were performed to define the basis for the unique growth requirements of M. haemophilum. We found that M. haemophilum, unlike many other mycobacteria, is unable to synthesize iron-binding siderophores known as mycobactins or to utilize ferri-mycobactins to support growth. These differences correlate with the absence of genes associated with mycobactin synthesis, secretion, and uptake. In agreement with the ability of heme to promote growth, we identified genes encoding heme uptake machinery. Consistent with its propensity to infect the skin, we show at the whole-genome level the genetic closeness of M. haemophilum with Mycobacterium leprae, an organism which cannot be cultivated in vitro, and we identify genes uniquely shared by these organisms. Finally, we identify means to express foreign genes in M. haemophilum. These data explain the unique culture requirements for this important pathogen, provide a foundation upon which the genome sequence can be exploited to improve diagnostics and therapeutics, and suggest use of M. haemophilum as a tool to elucidate functions of genes shared with M. leprae.

IMPORTANCE

Mycobacterium haemophilum is an emerging pathogen with an unknown natural reservoir that exhibits unique requirements for iron supplementation to grow in vitro. Understanding the basis for this iron requirement is important because it is fundamental to isolation of the organism from clinical samples and environmental sources. Defining the molecular basis for M. haemophilium's growth requirements will also shed new light on mycobacterial strategies to acquire iron and can be exploited to define how differences in such strategies influence pathogenesis. Here, through a combination of sequencing and experimental approaches, we explain the basis for the iron requirement. We further demonstrate the genetic closeness of M. haemophilum and Mycobacterium leprae, the causative agent of leprosy which cannot be cultured in vitro, and we demonstrate methods to genetically manipulate M. haemophilum. These findings pave the way for the use of M. haemophilum as a model to elucidate functions of genes shared with M. leprae.

Human infections due to nontuberculous mycobacteria: the infectious diseases and clinical microbiology specialists' point of view

Nontuberculous mycobacteria (>150 species such as Mycobacterium avium, Mycobacterium kansasii, Mycobacterium chelonae and Mycobacterium abscessus) are opportunistic pathogens causing lung and extrarespiratory infections, beside M. ulcerans and M. marinum that are pathogens causing specific skin and soft tissue infections. Disseminated infections occur only in severe immunosuppressed conditions such as AIDS. The diagnosis is based on repeated isolations of the same mycobacterium associated with clinical and radiological signs, and the absence of tuberculosis. Precise species identification is obtained by molecular biology. Therapeutic antibiotic regimens differ with regard to the mycobacterial species that are involved. Prevention of iatrogenic infections relies on using sterile water in all injections, healthcare and cosmetic occupations. Future perspectives are to set effective antibiotic regimens tested in randomized therapeutic trials.

Mycobacterium species related to M. leprae and M. lepromatosis from cows with bovine nodular thelitis

Bovine nodular thelitis is a granulomatous dermatitis associated with infection with acid-fast bacteria. To identify the mycobacterium responsible for this infection, we conducted phylogenetic investigations based on partial sequencing of 6 genes. These bacteria were identified as an undescribed Mycobacterium species that was phylogenetically related to M. leprae and M. lepromatosis.

Current and past strategies for bacterial culture in clinical microbiology

A pure bacterial culture remains essential for the study of its virulence, its antibiotic susceptibility, and its genome sequence in order to facilitate the understanding and treatment of caused diseases. The first culture conditions empirically varied incubation time, nutrients, atmosphere, and temperature; culture was then gradually abandoned in favor of molecular methods. The rebirth of culture in clinical microbiology was prompted by microbiologists specializing in intracellular bacteria. The shell vial procedure allowed the culture of new species of Rickettsia. The design of axenic media for growing fastidious bacteria such as Tropheryma whipplei and Coxiella burnetii and the ability of amoebal coculture to discover new bacteria constituted major advances. Strong efforts associating optimized culture media, detection methods, and a microaerophilic atmosphere allowed a dramatic decrease of the time of Mycobacterium tuberculosis culture. The use of a new versatile medium allowed an extension of the repertoire of archaea. Finally, to optimize the culture of anaerobes in routine bacteriology laboratories, the addition of antioxidants in culture media under an aerobic atmosphere allowed the growth of strictly anaerobic species. Nevertheless, among usual bacterial pathogens, the development of axenic media for the culture of Treponema pallidum or Mycobacterium leprae remains an important challenge that the patience and innovations of cultivators will enable them to overcome.

Mycobacterium haemophilum infection with prominent facial manifestation mimicking leprosy

Mycobacterium haemophilum is a slow-growing non-tuberculous mycobacterium that is rarely known to cause human skin infection, particularly in immunocompromised patients. We recently experienced a 69-year-old Japanese woman with this infection who had been under immunosuppressive treatment for recalcitrant rheumatoid arthritis. The patient showed disseminated erythematous plaques and subcutaneous nodules on the face and extremities, and interestingly, the face manifested with a striking "facies leontina" appearance. Biopsy revealed abscess and granulomatous dermatitis with the involvement of peripheral nerve bundles and the presence of innumerable acid-fast bacilli, thus necessitating differentiation from lepromatous leprosy. M. haemophilum was identified by molecular characterization as well as by successful culture with iron supplements. Although drug susceptibility testing indicated responsiveness to multiple antibiotics administrated simultaneously for the treatment, it took over 6 months to achieve significant improvement, and we also employed concurrent oral potassium iodide administration and repeated surgical excision. This case highlights the importance of continuous combination therapy for successful outcome in this rare infection. Furthermore, application of potassium iodide for mycobacterial infection warrants further evaluation by accumulating more cases.

Intraventricular granulomatous mass associated with Mycobacterium haemophilum: A rare central nervous system manifestation in a patient with human immunodeficiency virus infection

We report a rare case of Mycobacterium haemophilum presenting as an intraventricular granulomatous mass with loculated hydrocephalus and seizures in a patient with human immunodeficiency virus. M. haemophilum, a slow-growing mycobacteria, causes localized and disseminated disease among immunocompromised hosts. Central nervous system infection with M. haemophilum is extremely rare. Preoperative laboratory testing of our patient for tuberculosis, toxoplasmosis, sarcoidosis and histoplasmosis were negative. Surgical resection of the mass revealed a caseating granuloma that stained positive for acid-fast bacillus suggesting possible tuberculoma. Despite negative testing for tuberculosis, a polymerase chain reaction analysis was ultimately performed from the resected mass which revealed M. haemophilum. To our knowledge, this is the first case of M. haemophilum presenting as an intraventricular mass. We review the clinical manifestations of this pathogen and discuss the medical and surgical management.

Disseminated Mycobacterium haemophilum infection in an ASSAM trinket snake (Elaphe frenata)

A sub-adult male Assam trinket snake (Elaphe frenata) that was confiscated from an exotic animal dealer was found dead in its enclosure after a 17-mo quarantine. The snake had grown well during that period and had no physical examination or bloodwork abnormalities during the quarantine. On gross necropsy, masses were found in the epaxial musculature and stomach, the lung was diffusely thickened, the ventricular wall was mottled, and there was intracoelomic and pericardial effusion. Histopathology revealed diffusely disseminated granulomatous infiltrates throughout the lung interstitium and multifocal granulomatous infiltrates in the transmural gastric mass, within the myocardium and pericardial adipose tissue, in the liver and kidney parenchyma, in the cervical region surrounding the trachea and thyroid, and replacing the myofibers of the craniolateral epaxial muscles. Fite-Farracho acid-fast staining revealed numerous intracytoplasmic acid-fast bacilli within macrophages, and polymerase chain reaction testing on frozen tissues followed by nucleic acid sequencing of polymerase chain reaction amplicons identified Mycobacterium haemophilum.

Mycobacterium haemophilum bone and joint infection in HIV/AIDS: case report and literature review

We report a case of disseminated Mycobacterium haemophilum osteomyelitis in a patient with advanced HIV infection, who later developed recurrent immune reconstitution inflammatory syndrome after commencement of antiretroviral therapy. We review previous reports of M. haemophilum bone and joint infection associated with HIV infection and describe the management of M. haemophilum-associated immune reconstitution inflammatory syndrome, including the role of surgery as an adjunctive treatment modality and the potential drug interactions between antiretroviral and antimycobacterial agents.

Cutaneous tuberculosis overview and current treatment regimens

Tuberculosis is one of the oldest diseases known to humankind and it is currently a worldwide threat with 8-9 million new active disease being reported every year. Among patients with co-infection of the human immunodeficiency virus (HIV), tuberculosis is ultimately responsible for the most deaths. Cutaneous tuberculosis (CTB) is uncommon, comprising 1-1.5% of all extra-pulmonary tuberculosis manifestations, which manifests only in 8.4-13.7% of all tuberculosis cases. A more accurate classification of CTB includes inoculation tuberculosis, tuberculosis from an endogenous source and haematogenous tuberculosis. There is furthermore a definite distinction between true CTB caused by Mycobacterium tuberculosis and CTB caused by atypical mycobacterium species. The lesions caused by mycobacterium species vary from small papules (e.g. primary inoculation tuberculosis) and warty lesions (e.g. tuberculosis verrucosa cutis) to massive ulcers (e.g. Buruli ulcer) and plaques (e.g. lupus vulgaris) that can be highly deformative. Treatment options for CTB are currently limited to conventional oral therapy and occasional surgical intervention in cases that require it. True CTB is treated with a combination of rifampicin, ethambutol, pyrazinamide, isoniazid and streptomycin that is tailored to individual needs. Atypical mycobacterium infections are mostly resistant to anti-tuberculous drugs and only respond to certain antibiotics. As in the case of pulmonary TB, various and relatively wide-ranging treatment regimens are available, although patient compliance is poor. The development of multi-drug and extremely drug-resistant strains has also threatened treatment outcomes. To date, no topical therapy for CTB has been identified and although conventional therapy has mostly shown positive results, there is a lack of other treatment regimens.

Recurrent Mycobacterium haemophilum in a renal transplant recipient

Mycobacterium haemophilum is a rare isolate of non-tuberculous Mycobacterium which has been reported to affect immunocompromised patients. We report a case of a 32-year-old renal transplant patient with M.  haemophilum infection initially involving his left sinus which was treated with appropriate antimicrobial therapy for thirteen months. Two weeks after cessation of antibiotics the infection rapidly recurred in his skin and soft tissues of his hands and feet. This case highlights the difficult diagnostic and therapeutic implications of atypical infections in transplant patients. To our knowledge this is the first reported case of relapsed M.  haemophilum infection in a renal transplant recipient.

Infections caused by non-tuberculous mycobacteria in recipients of hematopoietic stem cell transplantation

Non-tuberculous mycobacteria (NTM) are acid-fast bacteria that are ubiquitous in the environment and can colonize soil, dust particles, water sources, and food supplies. They are divided into rapidly growing mycobacteria such as Mycobacterium fortuitum, Mycobacterium chelonae, and Mycobacterium abscessus as well as slowly growing species such as Mycobacterium avium, Mycobacterium kansasii, and Mycobacterium marinum. About 160 different species, which can cause community acquired and health care-associated infections, have been identified. NTM are becoming increasingly recognized in recipients of hematopoietic stem cell transplantation (HSCT) with incidence rates ranging between 0.4 and 10%. These infections are 50–600 times commoner in transplant recipients than in the general population and the time of onset ranges from day 31 to day 1055 post-transplant. They have been reported following various forms of HSCT. Several risk factors predispose to NTM infections in recipients of stem cell transplantation and these are related to the underlying medical condition and its treatment, the pre-transplant conditioning therapies as well as the transplant procedure and its complications. Clinically, NTM may present with: unexplained fever, lymphadenopathy, osteomyelitis, soft tissue and skin infections, central venous catheter infections, bacteremia, lung, and gastrointestinal tract involvement. However, disseminated infections are commonly encountered in severely immunocompromised individuals and bloodstream infections are almost always associated with catheter-related infections. It is usually difficult to differentiate colonization from true infection, thus, the threshold for starting therapy remains undetermined. Respiratory specimens such as sputum, pleural fluid, and bronchoalveolar lavage in addition to cultures of blood, bone, skin, and soft tissues are essential diagnostically. Susceptibility testing of mycobacterial isolates is a basic component of optimal care. Currently, there are no guidelines for the treatment of NTM infections in recipients of stem cell transplantation, but such infections have been successfully treated with surgical debridement, removal of infected or colonized indwelling intravascular devices, and administration of various combinations of antimicrobials. Monotherapy can be associated with development of drug resistance due to new genetic mutation. The accepted duration of treatment is 9 months in allogeneic stem cell transplantation and 6 months in autologous setting. Unfortunately, eradication of NTM infections may be impossible and their treatment is often complicated by adverse effects and interactions with other transplant-related medication.

Mycobacterial skin and soft tissue infection

Mycobacterial skin and soft tissue infection (SSTI) includes nontuberculous mycobacterial (NTM) infections, tuberculosis (TB), and leprosy. Diagnosis of mycobacterial SSTI can be challenging due to diverse clinical presentation, low yield from cultured specimens, and nonspecific histopathology on tissue biopsy. In addition, immunosuppressed patients may present with atypical or disseminated disease. Despite aggressive medical treatment and often with surgical intervention, results may be suboptimal with poor outcomes. Regimens typically require multiple antibiotics for extended periods of time and are often complicated by medication side effects and drug-drug interactions. Biopsy with culture is the gold standard for diagnosis, but newer molecular diagnostics and proteomics such as matrix-assisted laser desorption ionization-time of flight mass spectrometry have improved diagnosis with increased identification of clinically significant mycobacteria species in clinically relevant time frames. We will review updates in diagnostic tests along with clinical presentation and treatment of mycobacterial SSTI for NTM, TB, and leprosy.

Central nervous system infection due to Mycobacterium haemophilum in a patient with acquired immunodeficiency syndrome

Mycobacterium haemophilum is an environmental organism that rarely causes infections in humans. We report a patient with acquired immunodeficiency syndrome who had central nervous system infection due to M. haemophilum. The diagnosis required brain tissue procurement and molecular identification method while the treatment outcome was unfavourable.

Chiasmitis caused by Mycobacterium haemophilum in an immunocompromised adult

We report a case of chiasmitis caused by a rare nontuberculous mycobacterium in an immunocompromised patient. A 44-year-old man with a history of AIDS presented with recurrent vision loss and headache. Magnetic resonance imaging (MRI) demonstrated an enhancing mass involving the optic chiasm. Histopathologic and microbiological evaluation revealed infection with Mycobacterium haemophilum. While combination antimicrobial and steroid therapy contributed to improvement in his vision, the patient's symptoms recurred. Follow-up MRI showed extension of infection to the hypothalamus and leptomeninges, indicative of basilar meningitis. MRI is a valuable tool for early diagnosis of chiasmitis as well as for monitoring infection progression and treatment response.

Mycobacterium haemophilum as the Initial Presentation of a B-Cell Lymphoma in a Liver Transplant Patient

A 66-year-old woman presented with pustular lesions of her face, trunk, and limbs and an acute arthritis of the knees and elbows. She had a complex medical background and had been on immunosuppressants for three years after a liver transplant. Tissue samples from her skin lesions and synovial fluid showed acid-fast bacilli. Mycobacterium haemophilum, an atypical mycobacteria, was later grown on culture. During her treatment with combination antibiotic therapy, she developed a pronounced generalised lymphadenopathy. Histology showed features of a diffuse B-cell lymphoma, a posttransplant lymphoproliferative disorder (PTLD).

Mycobacterium haemophilum Masquerading as Leprosy in a Renal Transplant Patient

Opportunistic infections following immunosuppression in solid organ transplant (SOT) patients are common complications with the skin being a common sight of infection. Nontuberculous mycobacteria (NTM) are rare but potential causes of skin infection in SOT patients. We present a case of an adult male immunosuppressed following renal transplantation who presented with an asymptomatic rash for several months. The patient's skin eruption consisted of erythematous papules and plaques coalescing into an annular formation. After failure of the initial empiric therapy, a punch biopsy was performed that demonstrated nerve involvement suspicious for Mycobacterium leprae. However, culture of the biopsy specimen grew acid-fast bacilli that were subsequently identified as M. haemophilum. His rash improved after a prolonged course of clarithromycin and ciprofloxacin. Both organisms are potential causes of opportunistic skin infections and can be difficult to distinguish with similar predilection for skin and other biochemical and genetic similarities. Ultimately they can be distinguished with culture as M. haemophilum will grow in culture and M. leprae will not. This case was unique due to nerve involvement on biopsy which is classically seen on biopsies of leprosy.

Disseminated Mycobacterium haemophilum infection in a 72-year-old patient with rheumatoid arthritis on infliximab

Mycobacterium haemophilum is a slow growing, aerobic, fastidious mycobacterium requiring hemin and a temperature of 30-32° C for optimal growth that is ubiquitous in nature. Disease in immunocompromised adults typically manifests as skin lesions such as papules, pustules and ulcerations. This organism also causes lymphadenitis in immunocompetent children. Antitumour necrosis factor-α (anti-TNF-α) therapy with agents such as infliximab, etanercept and adalimumab is increasingly being used for immunosuppression in patients with various autoimmune conditions. These agents are known to place patients at increased risk for tuberculosis and other granulomatous diseases. However, little is known about illness caused by M haemophilum in patients on immunosuppression with anti-TNF-α therapy. We describe a case of disseminated M haemophilum manifesting as skin lesions in a 72-year-old man with rheumatoid arthritis on infliximab and methotrexate.

Epidemiology of cervico-facial pediatric lymphadenitis as a result of nontuberculous mycobacteria

Cervical lymphadenitis as a result of nontuberculous mycobacteria, otherwise known as scrofula, is a disease occurring almost exclusively in immunocompetent young children. The most frequent mycobacterial species responsible is Mycobacterium avium, but a large number of other species may also be involved. The epidemiology of such disease is revised here, and the impact of different species as causative agents of adenitis is also discussed.

Performance assessment of the DR. TBDR/NTM IVD kit for direct detection of Mycobacterium tuberculosis isolates, including rifampin-resistant isolates, and nontuberculous Mycobacteria

We evaluated the performance of the DR. TBDR/NTM IVD kit, which was designed to detect Mycobacterium tuberculosis, rifampin-resistant M. tuberculosis, and nontuberculous mycobacteria, for detecting 110 positive and 50 negative cultures in Mycobacterium Growth Indicator Tubes. The accuracy rate of this kit for identification of Mycobacterium species was 95.5% (105/110).