Non‐tuberculous Mycobacteria in Wild Boar (Sus scrofa) from Southern Spain: Epidemiological,Clinical and Diagnostic Concerns

Non‐tuberculous mycobacteria (NTM) are widely distributed in the environment, particularly in wet soil, marshland, rivers or streams, but also are causative agents of a wide variety of infections in animals and humans. Little information is available regarding the NTM prevalence in wildlife and their effects or significance in the bovine tuberculosis (bTB) epidemiology and diagnosis. This research shows the most frequently NTM isolated in lymph nodes of wild boar (Sus scrofa) from southern Spain, relating the NTM presence with the individual characteristics, the management of animals and the possible misdiagnosis of Mycobacterium bovis in concurrent infections. A total of 219 NTM isolates were obtained from 1249 wild boar mandibular lymph nodes sampled between 2007 and 2011. All but 75 isolates were identified by the PCR‐restriction analysis‐hsp65, and a partial sequencing of the 16S rDNA was carried out to identify the rest of the isolates. Results showed that Mycobacterium chelonae was the most frequently isolated NTM specie (133 isolates, 60.7%), followed by Mycobacterium avium (24 isolates, 11%). No relation was found regarding sex, body condition and management, but M. chelonae was more frequently detected in adults, whereas M. avium was more prevalent in subadults. The high NTM prevalence observed in the studied wild boar populations could make difficult the bTB diagnostic.     

Crescentic Glomerulonephritis Associated with Non-Tuberculous Mycobacteria Infection

A 72-year-old woman with a previous diagnosis of non-tuberculous mycobacteria (NTM) pulmonary disease was admitted because of hemoptysis and acute renal failure. A chest x-ray showed interstitial infiltration over bilateral lung fields. A kidney biopsy showed immune complex-mediated crescentic glomerulonephritis and diffuse endocapillary hypercellularity with exudative neutrophils. Reactive NTM infection of the lungs was suspected when mycobacterial cultures of the sputum repeatedly yielded Mycobacterium avium. A lung biopsy revealed chronic inflammation without evidence of alveolar capillaritis. NTM pulmonary disease was further confirmed by tissue culture of the lung biopsy specimens. Anti-tuberculous drugs in combination with clarithromycin were given for the treatment of NTM infection. Because of the risk of aggravating underlying infectious disease, immunosuppressive therapy for crescentic glomerulonephritis was not carried out. Pulmonary symptoms promptly responded to treatment. Furthermore, renal function steadily improved after the initiation of anti-NTM therapy. To our knowledge, this is the first report of crescentic glomerulonephritis associated with NTM infection.     

Surgical treatment of nontuberculous mycobacterial lung disease

While the prevalence of pulmonary tuberculosis has been decreasing, the prevalence of nontuberculous mycobacterial lung disease has been increasing. Unlike tuberculosis, nontuberculous mycobacterial disease is not communicable. However, their indolent nature may result in extensive parenchymal destruction, causing respiratory failure and vulnerability to airway infection. Nontuberculous mycobacterial lung disease, therefore, has been becoming a significant health problem. According to the 2007 American Thoracic Society/Infectious Diseases Society of America statement on nontuberculous mycobacterial diseases, the primary treatment is a multidrug treatment regimen. However, its efficacy is less than satisfactory for Mycobacterium avium complex lung disease, which is the most common type of nontuberculous mycobacterial lung diseases, and for Mycobacterium abscessus lung disease, which is notoriously resistant to chemotherapeutic drugs. The statement, therefore, has proposed a multidisciplinary treatment approach for these types of nontuberculous mycobacterial lung diseases: a combination of multidrug treatment regimen and adjuvant resectional surgery. This review covers the rationale, indication, procedure, and outcome of surgical treatment of nontuberculous mycobacterial lung disease. The rationale of surgery is to prevent disease progressing by removing the areas of lung most affected, harboring the largest amounts of mycobacteria. The indications for surgery include a poor response to drug therapy, the development of macrolide-resistant disease, or the presence of a significant disease-related complication such as hemoptysis. The surgical procedures of choice are various types of pulmonary resections, including wedge resection, segmentectomy, lobectomy, or pneumonectomy. The reported series have achieved favorable treatment outcomes in surgically treated patients with acceptable morbidity and mortality rates.     

Non tuberculous mycobacteria in surgical wounds- a rising cause of concern?

Introduction  

The non-tuberculous mycobacteria (NTM) have emerged as important opportunistic pathogens in the recent years. The NTM are rapid growing mycobacteria (RGM), which include Mycobacterium fortuitum and M. chelonae and are grouped as M. fortuitum-chelonae complex. Non-healing postoperative wound infections that do not respond to antibiotics used for pyogenic infections and having sterile routine aerobic cultures should raise a suspicion of NTM.     

Mycobacterium szulgai Infection after Carpal Tunnel Release Requiring Extensive Debridement and ALT Flap Reconstruction

Nontuberculous mycobacteria (NTM) refer to all mycobacteria species not associated with the Mycobacterium tuberculosis complex. NTM have been shown to cause superficial and deep tissue infections of the hand, the vast majority of which are attributed to Mycobacterium marinum . There have been only eight cases of Mycobacterium szulgai -associated infections of the hand described in the English literature, none requiring surgical reconstruction. We describe a severe case of M. szulgai -associated carpal tunnel infection reported in an immunocompetent patient requiring extensive soft tissue debridement and reconstruction. This case illustrates the importance of a multidisciplinary team approach with microbiology specialists when managing severe soft tissue infections of the hand.     

Urine lipoarabinomannan as a marker for low-risk of NTM infection in the CF airway

BackgroundIndividuals with Cystic fibrosis (CF) are the most vulnerable population for pulmonary infection with nontuberculous mycobacteria (NTM). Screening, diagnosis, and assessment of treatment response currently depend on traditional culture techniques, but sputum analysis for NTM in CF is challenging, and associated with a low sensitivity. The cell wall lipoarabinomannan (LAM), a lipoglycan found in all mycobacterial species, and has been validated as a biomarker in urine for active Mycobacterium tuberculosis infection.MethodsUrine from a CF cohort (n = 44) well-characterized for NTM infection status by airway cultures was analyzed for LAM by gas chromatography/mass spectrometry. All subjects with positive sputum cultures for NTM had varying amounts of LAM in their urine. No LAM was detected in subjects who never had a positive culture (14/45). One individual initially classified as NTM sputum negative subsequently developed NTM disease 657 days after the initial urine LAM testing. Repeat urine LAM testing turned positive, correlating to her positive NTM status. Subjects infected with subspecies of M. abscessus had greater LAM quantities than those infected with M. avium complex (MAC). There was no correlation with disease activity or treatment status and LAM quantity. A TB Capture ELISA using anti-LAM antibodies demonstrated very poor sensitivity in identifying individuals with positive NTM sputum cultures.ConclusionThese findings support the conclusion that urine LAM related to NTM infection may be a useful screening test to determine patients at low risk for having a positive NTM sputum culture, as part of a lifetime screening strategy in the CF population.     

Nontuberculous mycobacterial infections in left ventricular assist device patients

Left ventricular assist devices (LVADs) are integral for the management of medically refractory heart failure, and LVAD infections are common following device placement. Most infections are caused by Staphylococcal spp. and Gram-negative enteric bacteria but nontuberculous mycobacterial (NTM) infections have been reported. We present the second-ever reported case of a driveline infection caused by Mycobacterium fortuitum in a 75-year-old male with a continuous-flow LVAD. After receiving meropenem, azithromycin, and ciprofloxacin, he underwent device exchange and ultimately died after failing to recover neurologically. Management of NTM infections presents a clinical challenge due to the propensity for rapidly growing mycobacterial species to form biofilms and the possibility of negative cultures delaying diagnosis. To address the literature gap surrounding NTM infections in LVAD patients, we performed a systematic review and present all previously reported cases.     

Clofazimine inhalation suspension for the aerosol treatment of pulmonary nontuberculous mycobacterial infections

BackgroundNontuberculous mycobacteria are recognized as a concern for cystic fibrosis (CF) patients due to increasing disease prevalence and the potential for detrimental effects on pulmonary function and mortality. Current standard of care involves prolonged systemic antibiotics, which often leads to severe side effects and poor treatment outcomes. In this study, we investigated the tolerability and efficacy of a novel inhaled therapeutic in various mouse models of NTM disease.MethodsWe developed clofazimine inhalation suspension (CIS), a novel formulation of clofazimine developed for inhaled administration. To determine the efficacy, minimum inhibitory concentrations were evaluated in vitro, and tolerability of CIS was determined in naïve mouse models over various durations. After establishing tolerability, CIS efficacy was tested in in vivo infection models of both Mycobacterium avium and M. abscessus. Lung and plasma clofazimine levels after chronic treatments were evaluated.ResultsClofazimine inhalation suspension demonstrated antimycobacterial activity in vitro, with MIC values between 0.125 and 2 μg/ml for M. avium complex and M. abscessus. Administration into naïve mice showed that CIS was well tolerated at doses up to 28 mg/kg over 28 consecutive treatments. In vivo, CIS was shown to significantly improve bacterial elimination from the lungs of both acute and chronic NTM-infected mouse models compared to negative controls and oral clofazimine administration. Clofazimine concentrations in lung tissue were approximately four times higher than the concentrations achieved by oral dosing.ConclusionClofazimine inhalation suspension is a well tolerated and effective novel therapeutic candidate for the treatment of NTM infections in mouse models.     

Nontuberculous mycobacterial exit-site infection and abscess in a peritoneal dialysis patient

Nontuberculous mycobacterial infections of peritoneal dialysis catheter exit sites have rarely been reported in patients on peritoneal dialysis. We report here a case of Mycobacterium abscessus exit site infection with abdominal wall abscess formation in an adolescent on peritoneal dialysis, which required long-term antibiotic therapy, peritoneal dialysis catheter removal, and surgical debridement of the abscess. Nontuberculous mycobacteria should be considered as a possible causative organism for an exit site infection that fails to respond to usual antibiotic therapy. Nontuberculous mycobacterial exit site infections may require peritoneal dialysis catheter removal and surgical debridement.     

Distribution and outcomes of infection of Mycobacterium avium complex species in cystic fibrosis

BackgroundThe majority of nontuberculous mycobacterial (NTM) pulmonary infections in people with cystic fibrosis (CF) are caused by Mycobacterium avium complex (MAC) species. Data on MAC species distribution and outcomes of infection in CF are lacking.MethodsThis was a single center, retrospective study. MAC isolates had species identification with MLSA of rpoB and the 16S23S ITS region. Clinical data were compared between species.ResultsTwenty-three people with CF and 57 MAC isolates were included. Infection with M. avium was the most common (65.2%). M. intracellulare was associated with higher rates of NTM disease, younger age, and steeper decline in lung function prior to infection.ConclusionsWe observed worse clinical outcomes in people with M. intracellulare infection relative to other MAC species. Further investigation of clinical outcomes of MAC infection among CF patients is warranted to better define the utility of species-level identification of MAC isolates in CF.     

Non‐tuberculous Mycobacteria isolated from lymph nodes and faecal samples of healthy slaughtered cattle and the abattoir environment

Infections caused by non‐tuberculous mycobacteria (NTM ) are reported as emerging disease in many countries worldwide. The occurrence of NTM in different hosts and their implication as obligate or opportunistic pathogen remain largely unclear. Lymph nodes and faecal samples of clinically healthy Swiss cattle at slaughter were analysed for the presence of NTM . Based on the examined lymph nodes, NTM were detected in 20% of 108 cattle originating from different premises. The 22 isolates belonged to five different species of Mycobacteria (M. avium subsp. hominissuis , M. kansasii , M. persicum , “M. lymphaticum” and M. europaeum ). M. avium subsp. hominissuis (63%) and M. kansasii (18%) thereby predominated and were found in lymph nodes with and without macroscopic changes. Moreover, M. persicum found in two cattle has recently been described as a human pathogen and is closely related to M. kansasii . Amongst cattle with lymph nodes positive for mycobacteria, viable NTM were occasionally also detected in bovine faeces. However, the isolated NTM species from lymph nodes and respective faecal samples (M. hassiacum , M. phlei and M. vaccae ) did not coincide. Moreover, NTM species identified amongst isolates from the slaughterhouse environment clearly differed from those from lymph nodes and faecal samples, excluding cross‐contamination of the tissue specimens through the environment or laboratory processing. Assuming that some NTM interfere with the detection of bovine tuberculosis (bTB ), the present findings in healthy animals emphasize the need of more specific diagnostic tools for bTB eradication programs.     

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.     

Isolation and Potential for Transmission of Mycobacterium bovis at Human–livestock–wildlife Interface of the Serengeti Ecosystem,Northern Tanzania

Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), is a multihost pathogen of public health and veterinary importance. We characterized the M. bovis isolated at the human–livestock–wildlife interface of the Serengeti ecosystem to determine the epidemiology and risk of cross‐species transmission between interacting hosts species. DNA was extracted from mycobacterial cultures obtained from sputum samples of 472 tuberculosis (TB) suspected patients and tissue samples from 606 livestock and wild animal species. M. bovis isolates were characterized using spoligotyping and Mycobacterial Interspersed Repetitive Units‐Variable Tandem Repeats (MIRU‐VNTR) on 24 loci. Only 5 M. bovis were isolated from the cultured samples. Spoligotyping results revealed that three M. bovis isolates from two buffaloes (Syncerus caffer) and 1 African civet (Civettictis civetta) belonged to SB0133 spoligotype. The two novel strains (AR1 and AR2) assigned as spoligotype SB2290 and SB2289, respectively, were identified from indigenous cattle (Bos indicus). No M. bovis was detected from patients with clinical signs consistent with TB. Of the 606 animal tissue specimens and sputa of 472 TB‐suspected patients 43 (7.09%) and 12 (2.9%), respectively, yielded non‐tuberculous mycobacteria (NTM), of which 20 isolates were M. intracellulare. No M. avium was identified. M. bovis isolates from wildlife had 45.2% and 96.8% spoligotype pattern agreement with AR1 and AR2 strains, respectively. This finding indicates that bTB infections in wild animals and cattle were epidemiologically related. Of the 24 MIRU‐VNTR loci, QUB 11b showed the highest discrimination among the M. bovis strains. The novel strains obtained in this study have not been previously reported in the area, but no clear evidence for recent cross‐species transmission of M. bovis was found between human, livestock and wild animals.     

Acute empyema with intractable pneumothorax associated with ruptured lung abscess caused by <Emphasis Type="Italic">Mycobacterium avium</Emphasis>

Nontuberculous mycobacterial lung disease rarely features pleural involvement. Therapeutic strategies for this situation have not been well established. We present a case of acute empyema with intractable pneumothorax associated with ruptured lung abscess caused by Mycobacterium avium in an immunocompromised patient. Combined treatment that included multidrug antibiotic therapy and nonresectional surgery resulted in a good outcome.     

Identification of mycobacteria species by molecular methods

In this study, mycobacteria, which were previously identified as Mycobacterium tuberculosis complex (MTC), and mycobacteria other than tuberculosis (MOTT) with cord factor and the p‐nitro‐alpha‐acetyl‐amino‐beta‐hydroxypropiophenone (NAP) test were reanalysed using the polymerase chain reaction—restriction fragment length polymorphism (PCR‐RFLP) analysis method in order to confirm the identification, and at the same time, species accepted as MOTT were identified. Although the results of the NAP test were obtained within 3‐5 days, the PCR‐RFLP results were obtained in 1 day. Ten species identified as MTC with the NAP test and cord factor were confirmed with the PCR‐RFLP method. Fourteen species accepted as MOTT were identified as Mycobacterium species with the evaluation of the bands observed after the restriction of PCR product with the PCR‐RFLP method. These were as follows: three species Mycobacterium intracellulare type I, two species Mycobacterium phlei, two species Mycobacterium kansasii, one species Mycobacterium fortuitum type I, one species Mycobacterium gordonae type I, one species Mycobacterium abscessus type I, one species Mycobacterium scrofulaceum, one species Mycobacterium szulgai type I, one species Mycobacterium avium type II, and one species Mycobacterium terrae. Hence, the results of both the cord factor and the NAP test were confirmed with the molecular method, and at the same time, mycobacteria species identification was made by determining the fastest, easiest, and the most accurate result‐giving method. Because PCR‐RFLP is a very rapid method that provides exact identification of mycobacteria species, it can be performed in routine procedures.     

Management of De Novo Mycobacterial Infection After Lung Transplantation Without Rifampicin: Case Series of a Single Institution

Background and Objectives

To treat organ transplant patients with mycobacterial infection, physicians need to pay attention to interaction between drugs used against mycobacteria and immunosuppressants. The purpose of this report is to describe the clinical features of and treatment for mycobacterial infection in lung transplant (LTx) recipients.

Immune Reconstitution Inflammatory Syndrome Secondary to Mycobacterium kansasii Infection in a Kidney Transplant Recipient

Nontuberculous mycobacteria (NTM) infection is a challenging diagnosis for clinicians in solid organ transplantation. Immune reconstitution inflammatory syndrome (IRIS) is so far unreported in this context. We report here the case of a renal transplant recipient who developed Mycobacterium kansasii–associated lymphadenitis complicated by IRIS while undergoing reduction of his immunosuppressive therapy. For IRIS, the patient required low‐dose steroids and an increase in global immunosuppression, in association with NTM antibiotherapy.     

Antibody response against Mycobacterium avium complex in cystic fibrosis patients measured by a novel IgG ELISA test

BackgroundEarly signs of Mycobacterium avium complex pulmonary disease can be missed in patients with cystic fibrosis due to subclinical infection or delays in mycobacterial culture. The aim of this study was to determine the diagnostic accuracy of a novel enzyme linked immunosorbent assay for immunoglobulin G against Mycobacterium avium complex, which could help stratify patients according to risk.MethodsA retrospective cross sectional analysis of serum samples from the Copenhagen Cystic Fibrosis Center was performed. Corresponding clinical data were reviewed and patients with cystic fibrosis were assigned to one of four groups based on their mycobacterial culture results. In addition, anti-Mycobacterium avium complex immunoglobulin G levels were measured longitudinally before and after first positive culture in the period 1984–2015.ResultsThree-hundred and five patients with cystic fibrosis were included with a median of five nontuberculous mycobacterial cultures. Four individuals had Mycobacterium avium complex pulmonary disease at the time of cross sectional testing and their median antibody level was 22-fold higher than patients with no history of infection (1820 vs. 80 IgG units; p < 0.001). Test sensitivity was 100% (95% CI 40–100) and specificity 77% (95% CI 72–81). Longitudinal kinetics showed rising antibodies prior to first positive culture suggesting diagnostic delay.ConclusionsAntibody screening for Mycobacterium avium complex may be used as a supplement to culture. Although confirmation in a larger cohort is needed, our findings suggest that stratifying a cystic fibrosis population into high- and low-risk groups based on antibody levels may help clinicians identify patients in need of more frequent culture.     

Non-tuberculous pulmonary infections in Scotland: a cluster in Lothian?

BACKGROUND--A retrospective study was carried out to confirm the clinical impression that, in Lothian, non-tuberculous mycobacterial infections are as common as pulmonary tuberculosis. METHODS--All pulmonary isolates of Mycobacterium tuberculosis/bovis and non-tuberculous mycobacteria in Scotland from April 1990 to March 1993, and the notes of all patients with M malmoense isolates in Lothian, were reviewed. Information on mycobacterial culture procedures in Scottish laboratories was obtained as part of an audit project. RESULTS--Of all pulmonary isolates of mycobacteria in Lothian 53% (108/205) were non-tuberculous strains compared with 18% (140/800) for Scotland outside Lothian. Although comparable in population size and laboratory techniques, Lothian (108) had almost twice as many isolates of non-tuberculous mycobacteria as Glasgow (56), but the proportions of M malmoense and M avium intracellulare complex were similar in both areas. Of 41 patients with M malmoense isolates in Lothian 30 (75%) had clinically significant lung disease; only one was HIV positive. CONCLUSIONS--Non-tuberculous mycobacteria pose an increasing clinical problem in Scotland as a cause of pulmonary disease. There is a cluster of cases with M malmoense infection in Lothian which cannot be attributed to the high local prevalence of HIV.     

Chronic Multifocal Mycobacterium fortuitum Osteomyelitis Following Penetrating Plantar Trauma

We present the case of a 10-year-old girl with Mycobacterium fortuitum osteomyelitis following a plantar puncture wound with vegetative material. Nontuberculous mycobacterial (NTM) skin and soft tissue infections are well described in immunocompromised populations. However, NTM infection can also be seen in healthy hosts following direct inoculation. Magnetic resonance imaging examination demonstrated multifocal midfoot and metatarsal osteomyelitis. Surgical exploration revealed caseation necrosis and a chronic draining sinus tract. Combined surgical debridement and medical therapy resulted in clinical cure. A high index of suspicion and adequate collection and handling of surgical specimens facilitate the diagnosis and treatment of NTM skin and soft tissue infections.