Disseminated infection with Mycobacterium gordonae: report of a case and critical review of the literature

COVID-19 and Cavitary Lesion in Lung

The clinical manifestations of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are widespread, ranging from asymptomatic to critical illness with significant morbidity and mortality. It is widely known that individuals who have viral respiratory infections are more likely to develop bacterial infections. Throughout the pandemic, despite the fact that COVID-19 was thought to be the primary cause of millions of deaths, bacterial coinfections, superinfections, and other secondary complications played a significant role in the increased mortality rate. In our case, a 76-year-old male presented to the hospital complaining of shortness of air. Polymerase chain reaction (PCR) testing was positive for COVID-19 and cavitary lesions were discovered on imaging. Treatment was guided based on the results of bronchoscopy with bronchoalveolar lavage (BAL) cultures showing methicillin-resistant Staphylococcus aureus (MRSA) and Mycobacterium gordonae. However, the case was later complicated by the development of a pulmonary embolism after anticoagulants were held due to new onset hemoptysis. Our case highlights the importance of considering bacterial coinfection in cavitary lung lesions, appropriate antimicrobial stewardship, and close follow-up for full recovery in COVID-19 infections.

Isolation and Genomic Analysis of an Intracellular Mycobacterium gordonae from a Free-Living Acanthamoeba sp. in a Hospital Environment in Lima, Peru

Mycobacterium gordonae is a nontuberculous mycobacterium found in diverse environments and is considered an opportunistic pathogen in immunocompromised patients. We report the draft genome sequence of a Mycobacterium gordonae strain isolated from a free-living amoeba found in a nosocomial environment in Lima, Peru.

Identification of nontuberculous mycobacteria isolated from household showerheads of patients with nontuberculous mycobacteria

This study aimed to examine whether nontuberculous mycobacteria (NTM) inside household showerheads are identical to those in patients with NTM-pulmonary disease (PD) since household water is one of the potential NTM sources. Samples were obtained from 32 household showerheads of patients with NTM-PD recruited through the Pulmonary Outpatient Department at the Severance Hospital between October 2018 and October 2019. All isolates from patients with NTM-PD were diagnosed using a reverse-hybridization line probe assay based on the ropB gene. To determine the mycobacterial compositions, the washing fluids were collected and investigated using multiplex polymerase chain reaction assay and NTM culture; suspected microbial isolates in these fluids and culture were identified using sequencing analysis of 16S rRNA gene. NTM species causing the PD in the patients were Mycobacterium avium, M. intracellulare, M. abscessus, M. massiliense, and M. fortuitum complex. The mycobacteria isolated from the showerhead were M. lentiflavum, M. gordonae, M. triplex, M. phocaicum, M. mucogenicum, M. florentinum, M. gilvum, M. llatzerense, and M. peregrinum. However, the species identified in the showerheads did not match those of the patients. Despite NTM species in the showerheads, clinical implications in the main pathogenesis associated with the disease in the patients studied were not elucidated.

Mycobacterium avium-intracellulare complex promote release of pro-inflammatory enzymes matrix metalloproteinases by inducing neutrophil extracellular trap formation

The prevalence of and mortality from non-tuberculous mycobacteria (NTM) infections have been steadily increasing worldwide. Most NTM infections are caused by Mycobacterium avium-intracellulare complex (MAC). MAC can escape from killing by neutrophils, which are professional phagocytes. However, the involvement of neutrophils in the pathogenesis of MAC infection is poorly understood. The present study assessed the roles of neutrophil extracellular trap (NET) formation in neutrophil defense mechanisms against infection with MAC strains, including M. avium isolated from patients with severe or mild lung tissue destruction. Although all MAC induced NET formation, non-pathogenic mycobacteria (M. gordonae and M. smegmatis) slightly but not significantly induced NET formation. Peptidylarginine deiminase 4 (PAD4) inhibitor reduced MAC-induced NET formation but did not affect MAC escape from neutrophils. PAD4 inhibition attenuated the MAC-induced matrix metalloproteinase (MMP)-8 and 9 release to the levels of MMPs from non-pathogenic mycobacteria. MAC also induced interleukin (IL)-8 release by neutrophils, a process independent of MAC-induced NET formation. Taken together, these findings suggest that MAC induce NET formation, IL-8 release and NETs-dependent release of MMP-8 and -9 from neutrophils, leading to neutrophil accumulation and further inflammation, thereby enhancing the progression of infection in the lungs.

A Case Report: Ethambutol Causes a Rare Adverse Effect of Peripheral Neuropathy

Mycobacterium gordonae is a slow-growing acid-fast bacilli mycobacterium with low pathogenic potential. Patients with this infection are treated with antimycobacterial agents such as ethambutol, clarithromycin, and rifampin. We present a rare side effect of ethambutol causing peripheral neuropathy, along with regression of this upon discontinuation of the inciting medication. A 78-year-old male with a past medical history of lumbar degenerative disc disease and lumbosacral radiculopathy presented to the clinic with three weeks of progressively worsening rhinorrhea, nasal congestion, and productive cough with yellow sputum. After a bronchoalveolar lavage (BAL) and a chest computed tomography (CT) scan, he was diagnosed with an M. gordonae infection. He was started on a 12-month triple regimen of rifampin, clarithromycin, and high-dose ethambutol. During the first three months of antibiotic therapy, the patient began to have symptoms of gastrointestinal upset and worsening numbness in bilateral lower extremities, especially at night. Because he was unable to tolerate these adverse effects, the patient stopped taking these medications three months into his 12-month course. Upon stopping the antimycobacterial therapy, the patient’s neuropathy began to return to baseline. Based on imaging, electromyography (EMG), nerve conduction studies (NCS), and a literature search of antimycobacterial medicines, we concluded that the high dose of ethambutol is the most likely cause of this patient’s peripheral neuropathy. An important takeaway is that while ethambutol is a well-known cause of optic neuritis, it may also lead to peripheral neuropathy, which may regress upon discontinuation of the medication.

Clinical characteristics and imaging features of patients with nontuberculous mycobacteria in a tertiary care center

Background

Non-tuberculous mycobacteria (NTM) are ubiquitous organisms that occasionally causes invasive diseases in humans, but they are under-reported in Saudi Arabia. We aimed to describe NTM infections and apply the American Thoracic Society/Infectious Diseases Society of America ATS/IDSA criteria.

Method

Positive laboratory reports for NTM between January 2006 and December 2017 were retrospectively reviewed, and then classified into respiratory and non-respiratory specimens. ATS/IDSA criteria were applied to all respiratory specimens. Host status, clinical presentation, species identification, imaging, treatment, and outcome data were collected using a standardized form and analyzed. Cases with duplication or incomplete data were excluded.

Results

183 unique patients with positive NTM culture were included. Median age was 52 years and males represented 59%. Majority of cases were in the respiratory specimens group (n = 146), of which only 15 cases have met the ATS/IDSA criteria. Overall, cases were primarily known to have non-immunocompromising condition but 27% had either an active malignancy (n = 35), HIV (n = 13), or primary immunodeficiency (n = 8). 68.3% of cases presented with respiratory symptoms with or without fever. Among the identified NTM species (51.9%), slowly growing NTM were predominant. Anti-NTM therapy was provided in only 22.4% of this cohort. Death was documented only in 5 cases; all were in the respiratory group and were not treated.

Conclusion

Though uncommon to isolate, only one in every ten respiratory NTM isolates was found potentially true pathogen in a single center in Saudi Arabia. Future studies on NTM prevalence in Saudi Arabia are recommended.

Nontuberculous Mycobacteria, Macrophages, and Host Innate Immune Response

Although nontuberculous mycobacteria (NTM) are considered opportunistic infections, incidence and prevalence of NTM infection are increasing worldwide becoming a major public health threat. Innate immunity plays an essential role in mediating the initial host response against these intracellular bacteria. Specifically, macrophages phagocytose and eliminate NTM and act as antigen-presenting cells, which trigger downstream activation of cellular and humoral adaptive immune responses. Identification of macrophage receptors, mycobacterial ligands, phagosome maturation, autophagy/necrosis, and escape mechanisms are important components of this immunity network. The role of the macrophage in mycobacterial disease has mainly been studied in tuberculosis (TB), but limited information exists on its role in NTM. In this review, we focus on NTM immunity, the role of macrophages, and host interaction in NTM infection.

A very rare case of mycobacterium gordonae infection of the breast

Mastitis is a common disease in women with both infectious and noninfectious causes. Most cases occur during lactation and are caused by Staphylococcus aureus and Streptococcus species; parasites and Mycobacteria have rarely been reported to cause breast infections (Mandell, Douglas, and Bennett's principles and practice of infectious diseases (9th edn);2019, Am J Respir Crit Care Med. 2007;175:367). Nontuberculous mycobacteria (NTM) which are also referred to as atypical mycobacteria, mycobacteria other than tuberculosis (MOTT), or environmental mycobacteria are a large group of Mycobacteria which are becoming increasingly common cause of infection all over the world (Arch Dermatol. 2006;142:1287). NTM can cause infection diseases especially in immunocompromised patients, such as HIV-positive hosts, most commonly in the lungs, skin and soft tissue, lymph nodes or rarely spread with multiorgan dissemination (Arch Plast Surg. 2014;41:759). Mycobacterium gordonae (M. gordonae) is a slow-growing atypical mycobacterium that is considered the least pathogenic NTM. The organism is ubiquitous, and mostly isolated from soil and water. Despite its nonvirulent nature, clinically significant infections have been reported also in some immunocompetent patients (J Formosan Med Assoc. 2020, Clin Infect Dis. 1992;1229). We report the first documented case of breast infection in a young immunocompetent woman sustained by Mycobacterium Gordonae.

Mycobacterium gordonae infection in immunocompromised and immunocompetent hosts: A series of seven cases and literature review

BACKGROUND/PURPOSE

Mycobacterium gordonae is a ubiquitous environmental mycobacteria and has been long considered an opportunistic pathogen, causing infections only in immunocompromised hosts. Cases of M. gordonae related infections in immunocompetent host have rarely been reported, and the pathogenicity of M. gordonae remained uncertain.

METHODS

From January 2016 to December 2018, seven cases of M. gordonae infection were diagnosed and treated at National Taiwan University Hospital.

RESULTS

Six cases had at least one underlying disease affecting immune status, while one case had no identifiable underlying disease. The sites of infection were lung (n = 3), skin and soft tissue (n = 3), and one had disseminated disease involving the lung and bone marrow. All patients were cured after anti-mycobacterial treatment, except one patient died of refractory leukemia.

CONCLUSION

Compatible with the literature reports, we demonstrate that M. gordonae could be pathogenic and causing infection not only in the immunocompromised host, but also in the otherwise healthy population. Multi-antimicrobial combination and adequate source control could have good therapeutic effect for patients with M. gordonae infections.

Pulmonary non-tuberculous mycobacterial infections: current state and future management

Currently, there is a trend of increasing incidence in pulmonary non-tuberculous mycobacterial infections (PNTM) together with a decrease in tuberculosis (TB) incidence, particularly in developed countries. The prevalence of PNTM in underdeveloped and developing countries remains unclear as there is still a lack of detection methods that could clearly diagnose PNTM applicable in these low-resource settings. Since non-tuberculous mycobacteria (NTM) are environmental pathogens, the vicinity favouring host-pathogen interactions is known as important predisposing factor for PNTM. The ongoing changes in world population, as well as socio-political and economic factors, are linked to the rise in the incidence of PNTM. Development is an important factor for the improvement of population well-being, but it has also been linked, in general, to detrimental environmental consequences, including the rise of emergent (usually neglected) infectious diseases, such as PNTM. The rise of neglected PNTM infections requires the expansion of the current efforts on the development of diagnostics, therapies and vaccines for mycobacterial diseases, which at present, are mainly focused on TB. This review discuss the current situation of PNTM and its predisposing factors, as well as the efforts and challenges for their control.

Successful Treatment of Mycobacterium gordonae Sacroiliitis Using a Novel Minimally Invasive Sacroiliac Joint Arthrodesis: A Case Report

CASE

A 43-year-old man with a history of well-controlled HIV (human immunodeficiency virus) infection presented with sacroiliac joint destruction from a Mycobacterium gordonae infection. A sacroiliac joint arthrodesis was performed using a minimally invasive technique utilizing both biologic fusion (allograft bone with rhBMP-2 [recombinant human bone morphogenetic protein-2]) and fixation with titanium ingrowth rods.

CONCLUSION

To our knowledge, this is the first reported case of infectious sacroiliitis from a nontubercular mycobacterium (M. gordonae) treated with a combination of joint debridement, biologic fusion with bone graft, and nonbiologic functional fusion using titanium ingrowth rods, all performed in a minimally invasive fashion. This strategy effectively alleviated pain and preserved function at 2 years of follow-up.

Characterization of non-tuberculous mycobacterium from humans and water in an Agropastoral area in Zambia

Background

The non-tuberculous mycobacteria include those mycobacterium species that are not members of the Mycobacterium tuberculosis complex, the causative agent of pulmonary tuberculosis and Mycobacterium leprae. In Zambia, Non-tuberculous Mycobacteria are gaining recognition as pathogens of public health significance. However, there is scanty information on the isolation and speciation of these organisms for better patient management, consequently reducing the burden of these infections. Given the above information, the thrust of this study was to isolate and characterize NTM from humans and water in Namwala district of Zambia.

Method

This was a cross-sectional study were 153 individuals with suspected TB were sampled from four health facilities in Namwala district, sputum samples were also collected. Additionally, 149 water samples were collected from different water drinking sources such as Tap water, Borehole water, rivers, wells and streams. Standard TB culture methods were employed to isolate Non-tuberculous Mycobacteria and later 16S–23S internal transcribed spacer region Sequencing was employed to characterize NTM.

Results

Seven (7, 4.6%) NTM species were identified from humans with M. arupense (3, 42.9%) being the most common organism, while twenty three (23, 15.4%) NTM were identified from water with the common species being Mycobacterium gordonae (5, 21.7%). Mycobacterium avium and Mycobacterium fortuitum were both identified from human and water samples.

Conclusion

This study has shown the isolation of NTM species from humans and water. The isolation of NTM from drinking water sources could signify a public health risk to humans.

Blood antimicrobial activity varies against different Mycobacterium spp

In vitro analysis of mycobacterial pathogenicity or host susceptibility has traditionally relied on the infection of macrophages, the target cell of mycobacteria, despite difficulties reproducing their antimycobacterial activity. We have employed alternative models, namely whole blood and leukocytes in plasma, from QuantiFERON negative individuals, and performed infections with the pathogenic M. tuberculosis, the less pathogenic M. avium, M. kansasii and M. chelonae and the occasionally pathogenic M. gordonae and M. bovis. The anticoagulant used in blood extraction, heparin or EDTA, had a major influence in the outcome of the infection. Thus, while in the heparinized models a similar number of bacteria were enumerated in the inoculum and after seven days, in the presence of EDTA a killing effect was observed, despite the inhibitory effect of EDTA on cellular functions like the production of cytokines or reactive oxygen species (ROS). A special case was the rapidly growing mycobacteria M. chelonae, that multiplied in heparinized models but was eliminated in models with EDTA. We verified that EDTA is not responsible for the bactericidal effect, but acts as a bacteriostatic agent. Further work will determine whether blood derived models are a better alternative to the classical macrophage.

Cutaneous Mycobacterium gordonae infection in an elderly diabetic returned traveller

Mycobacterium gordonae, a low pathogenicity organism, is rarely implicated in skin and soft tissue infections. We present a 77-year-old returned diabetic traveler from rural Sudan with cutaneous M. gordonae infection. Several months of ciprofloxacin, rifampin and ethambutol led to resolution of his plaque, without signs of recurrence at 6-month follow-up.

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.

Applying the One Health Concept to Mycobacterial Research - Overcoming Parochialism

Mycobacterial infections remain a public health problem. Historically important, globally ubiquitous and with a wide host range, we are still struggling to control mycobacterial infections in humans and animals. While previous reviews have focused on individual mycobacterial infections in either humans or animals, a comprehensive review of the zoonotic aspect of mycobacteria in the context of the One Health initiative is lacking. With the purpose of providing a concise and comprehensive resource, we have collated literature to address the zoonotic potential of different mycobacterial species and elaborate on the necessity for an inter-sectorial approach to attain a new vision to combat mycobacterial infections.

Prevalence and diversity of Chlamydiales and other amoeba-resisting bacteria in domestic drinking water systems

A growing number of human infections incriminate environmental bacteria that have evolved virulent mechanisms to resist amoebae and use them as a replicative niche. These bacteria are designated amoeba-resisting bacteria (ARB). Despite the isolation of these ARB in various human clinical samples, the possible source of infection remains undetermined in most cases. However, it is known that the ARB Legionella pneumophila, for instance, causes a respiratory infection in susceptible hosts after inhalation of contaminated water aerosols from various sources. The Chlamydiales order contains many ARB, such as Parachlamydia acanthamoebae or Simkania negevensis, previously implicated in human respiratory infections with no identified contamination sources. We thus investigated whether domestic water systems are a potential source of transmission of these Chlamydiales to humans by using amoebal culture and molecular methods. Other important ARB such as mycobacteria and Legionella were also investigated, as were their possible amoebal hosts. This work reports for the first time a very high prevalence and diversity of Chlamydiales in drinking water, being detected in 35 (72.9%) of 48 investigated domestic water systems, with members of the Parachlamydiaceae family being dominantly detected. Furthermore, various Legionella and mycobacteria species were also recovered, some species of which are known to be causal agents of human infections.

Lipoarabinomannan binding to lactosylceramide in lipid rafts is essential for the phagocytosis of mycobacteria by human neutrophils

Pathogenic mycobacteria use virulence factors, including mannose-capped lipoarabinomannan (ManLAM), to survive in host phagocytic cells, such as neutrophils. We assessed the roles of lactosylceramide (LacCer, CDw17)-enriched lipid rafts in the phagocytosis of mycobacteria by human neutrophils and in the intracellular fate of phagocytosed mycobacteria. We showed that the association of the Src family kinase (SFK) Lyn with C24 fatty acid chain-containing LacCer was essential for the phagocytosis of mycobacteria by neutrophils. Assays with LacCer-containing liposomes, LacCer-coated plastic plates, and LAM-coated beads demonstrated that the phagocytosis of mycobacteria was mediated through the binding of LacCer to LAM. Both ManLAM from pathogenic species and phosphoinositol-capped LAM (PILAM) from nonpathogenic Mycobacterium smegmatis bound equivalently to LacCer to stimulate phagocytosis. However, PILAM from an M. smegmatis α1,2-mannosyltransferase deletion mutant (ΔMSMEG_4247), lacking the α1,2-monomannose side branches of the LAM mannan core, did not bind to LacCer or induce phagocytosis. An anti-LacCer antibody immunoprecipitated the SFK Hck from the phagosomes of neutrophils that internalized nonpathogenic mycobacteria but not from those that internalized pathogenic mycobacteria. Furthermore, knockdown of Hck by short inhibitory RNA abolished the fusion of lysosomes with phagosomes containing nonpathogenic mycobacteria. Further analysis showed that ManLAM, but not PILAM, inhibited the association of Hck with LacCer-enriched lipid rafts in phagosomal membranes, effectively blocking phagolysosome formation. Together, these findings suggest that pathogenic mycobacteria use ManLAM not only for binding to LacCer-enriched lipid rafts and entering neutrophils but also for disrupting signaling through Hck-coupled, LacCer-enriched lipid rafts and preventing phagolysosome formation.

Mycobacteria

The immunocompromised host is at increased risk of Mycobacterium tuberculosis complex and nontuberculous mycobacteria infection. Although Mycobacterium tuberculosis complex is a significant mycobacterial pathogen, nontuberculous mycobacteria causes substantial disease in those with suppressed immune responses. Mycobacterial infections can cause significant morbidity and mortality in this patient population, and rapid identification and susceptibility testing of the mycobacterial species is paramount to patient management and outcomes. Mycobacterial diagnostics has undergone some significant advances in the last two decades with immunodiagnostics (interferon gamma release assay), microscopy (light-emitting diode), culture (automated broth-based systems), identification (direct PCR, sequencing and matrix-assisted laser-desorption ionization–time of flight mass spectrometry) and susceptibility testing (molecular detection of drug resistance from direct specimens or positive cultures). Employing the most rapid and sensitive methods in the mycobacterial laboratory will have a tremendous impact on patient care and, in the case of Mycobacterium tuberculosis complex, in the control of tuberculosis.

First Draft Genome Sequence of a Mycobacterium gordonae Clinical Isolate

Here, we report the first draft genome sequence of the clinically relevant species Mycobacterium gordonae. The clinical isolate Mycobacterium gordonae 14-8773 was obtained from the sputum of a patient with mycobacteriosis.

Repeated acute kidney injury associated with Mycobacterium gordonae infection

Mycobacterium gordonae is a nontuberculous mycobacterium widely distributed in the environment. Although M. gordonae is not usually pathogenic and glomerular lesions due to M. gordonae are very rare, infection has been reported in both immunocompromised patients and healthy persons. We report a case of acute kidney injury (AKI) in which M. gordonae was ultimately identified as the cause. A 70-year-old man was admitted to our hospital because of fever, polyarthritis, and AKI. He was a hepatitis B virus carrier, suffered from diabetes, and had a past history of erysipelas. No causative bacteria were identified, but coexisting infection was suspected. The patient experienced remission with antibiotic therapy, but the same symptoms recurred eight times. Blood polymerase chain reaction was performed during the 7th recurrence, and M. gordonae was detected. Clarithromycin was initiated, but 2 years after initial hospitalization, the patient died due to M. gordonae infection. In this case, acute kidney injury was a consequence of infection-related glomerulonephritis due to M. gordonae. Mycobacterium is difficult to detect by routine culture methods; therefore, diagnosis remains challenging.

False-positive QuantiFERON TB-Gold test due to Mycobacterium gordonae

We report a case of QuantiFERON TB-Gold conversion associated to Mycobacterium gordonae in an elderly male from an assisted living facility without known risk factors for tuberculosis. This knowledge of environmental mycobacteria causing positive quantiferon assays is important to avoid unnecessary treatment of false-positive latent tuberculosis, especially in the absence of well-established positive predictive value of quantiferon conversion.

Disseminated Mycobacterium gordonae and Mycobacterium mantenii infection with elevated anti-IFN-γ neutralizing autoantibodies

A case of disseminated nontuberculous mycobacteria(l) (NTM) infection in a patient with positive neutralizing anti-interferon-γ (IFN-γ) autoantibodies involving bone, bronchus, systemic lymph nodes, and skin is reported. The causative NTMs were two different strains: Mycobacterium gordonae, which rarely causes true disease, and Mycobacterium mantenii, which is extremely rare. Anti-mycobacterial treatment successfully ameliorated all disseminated lesions. Although the concentration of anti-IFN-γ autoantibodies increased during the pre-treatment period, it gradually decreased after anti-mycobacterial treatment was started.

Pulmonary infection with caseating mediastinal lymphadenitis caused by Mycobacterium gordonae

It is often difficult to discern true mycobacterial infection from colonization due to Mycobacterium gordonae (M. gordonae) since this organism is ubiquitous and is commonly an innocuous saprophyte. This study reports a rare case of caseating hilar adenopathy and pulmonary disease caused by M. gordonae in a patient with chronic obstructive pulmonary disease (COPD) and rheumatoid arthritis (RA) on maintenance steroids and methotrexate. Pathologic exam and cultures of lymph node excision biopsy and bronchoalveolar lavage (BAL) confirmed the diagnosis. Triple antimycobacterial therapy with azithromycin, ethambutol and rifabutin was administered. The patient had significant clinical and radiologic improvement and follow-up cultures confirmed microbiologic cure. Mycobacterium gordonae can be a rare cause of significant pulmonary infection, and positive sputum or BAL cultures for M. gordonae should not be automatically discarded and considered as nonpathogenic contaminants or colonizing organisms, especially in immunocompromised hosts with comorbidities. A detailed review of the case and relevant literature is provided.

Temporal variations in the abundance and composition of biofilm communities colonizing drinking water distribution pipes

Pipes that transport drinking water through municipal drinking water distribution systems (DWDS) are challenging habitats for microorganisms. Distribution networks are dark, oligotrophic and contain disinfectants; yet microbes frequently form biofilms attached to interior surfaces of DWDS pipes. Relatively little is known about the species composition and ecology of these biofilms due to challenges associated with sample acquisition from actual DWDS. We report the analysis of biofilms from five pipe samples collected from the same region of a DWDS in Florida, USA, over an 18 month period between February 2011 and August 2012. The bacterial abundance and composition of biofilm communities within the pipes were analyzed by heterotrophic plate counts and tag pyrosequencing of 16S rRNA genes, respectively. Bacterial numbers varied significantly based on sampling date and were positively correlated with water temperature and the concentration of nitrate. However, there was no significant relationship between the concentration of disinfectant in the drinking water (monochloramine) and the abundance of bacteria within the biofilms. Pyrosequencing analysis identified a total of 677 operational taxonomic units (OTUs) (3% distance) within the biofilms but indicated that community diversity was low and varied between sampling dates. Biofilms were dominated by a few taxa, specifically Methylomonas, Acinetobacter, Mycobacterium, and Xanthomonadaceae, and the dominant taxa within the biofilms varied dramatically between sampling times. The drinking water characteristics most strongly correlated with bacterial community composition were concentrations of nitrate, ammonium, total chlorine and monochloramine, as well as alkalinity and hardness. Biofilms from the sampling date with the highest nitrate concentration were the most abundant and diverse and were dominated by Acinetobacter.

Current trends in nontuberculous mycobacteria infections in Canadian children: A pediatric investigators collaborative network on infections in Canada (PICNIC) study

BACKGROUND

Nontuberculous mycobacteria (NTM) infections appear to be increasing in number and severity in developed countries worldwide. Surgical excision has been considered the standard treatment for NTM lymphadenitis, but the use of medical therapy seems to be increasing.

OBJECTIVE

To determine the disease characteristics as well as the current therapeutic management of NTM infections in Canadian children.

METHODS

Cases of definite or probable NTM infections were identified prospectively in children up to 18 years of age seen in 10 Canadian paediatric tertiary care centres from September 2005 to August 2006. Clinical, microbiological and pathological data were collected.

RESULTS

A total of 60 cases were identified. Data were complete for 45 patients, including 34 cases of lymphadenitis, four cases of skin and soft tissue infection, and seven cases of pulmonary NTM infection. Seventy-nine per cent of children (27 of 34) with lymphadenitis had an unsuccessful course of antibiotics before diagnosis. Sixty-eight per cent of purified protein derivative tests (15 of 22) were positive. NTM was detected in 76% of samples (29 of 38), of which 62% were Mycobacterium avium complex. All patients with lymphadenitis underwent surgical therapy and most patients (74%) also received antimicrobials.

CONCLUSIONS

Current trends indicate that the majority of the study centres are using medical therapy with variable regimen and duration as an adjunct to surgical excision in the treatment of NTM lymphadenitis. Larger numbers and longer follow-up times are needed to better evaluate the efficacy of medical therapy and outcome of disease. A randomized controlled study comparing surgical therapy alone and chemotherapy for NTM lymphadenitis is required.

Occurrence of mycobacteria in bovine milk samples from both individual and collective bulk tanks at farms and informal markets in the southeast region of Sao Paulo, Brazil

BACKGROUND

Mycobacterium spp. is one of the most important species of zoonotic pathogens that can be transmitted from cattle to humans. The presence of these opportunistic, pathogenic bacteria in bovine milk has emerged as a public-health concern, especially among individuals who consume raw milk and related dairy products. To address this concern, the Brazilian control and eradication program focusing on bovine tuberculosis, was established in 2001. However, bovine tuberculosis continues to afflict approximately 1,3 percent of the cattle in Brazil. In the present study, 300 samples of milk from bovine herds, obtained from both individual and collective bulk tanks and informal points of sale, were cultured on Löwenstein-Jensen and Stonebrink media. Polymerase chain reaction (PCR)-based tests and restriction-enzyme pattern analysis were then performed on the colonies exhibiting phenotypes suggestive of Mycobacterium spp., which were characterized as acid-fast bacilli.

RESULTS

Of the 300 bovine milk samples that were processed, 24 were positively identified as Mycobacterium spp.Molecular identification detected 15 unique mycobacterial species: Mycobacterium bovis, M. gordonae, M. fortuitum, M. intracellulare, M. flavescens, M. duvalii, M. haemophilum, M. immunogenum, M. lentiflavum, M. mucogenicum, M. novocastrense, M. parafortuitum, M. smegmatis, M. terrae and M. vaccae. The isolation of bacteria from the various locations occurred in the following proportions: 9 percent of the individual bulk-tank samples, 7 percent of the collective bulk-tank samples and 8 percent of the informal-trade samples. No statistically significant difference was observed between the presence of Mycobacterium spp. in the three types of samples collected, the milk production profiles, the presence of veterinary assistance and the reported concerns about bovine tuberculosis prevention in the herds.

CONCLUSION

The microbiological cultures associated with PCR-based identification tests are possible tools for the investigation of the presence of Mycobacterium spp. in milk samples. Using these methods, we found that the Brazilian population may be regularly exposed to mycobacteria by consuming raw bovine milk and related dairy products. These evidences reinforces the need to optimize quality programs of dairy products, to intensify the sanitary inspection of these products and the necessity of further studies on the presence of Mycobacterium spp. in milk and milk-based products.

Nontuberculous Mycobacteria in household plumbing as possible cause of chronic rhinosinusitis

Millions of Americans live with chronic sinus infection. Most infections are caused by either bacteria or fungi. Some of these infections can be hard to treat, eluding medical and surgical treatment and persisting for months or even years. A recent study in New York found that some patients with a chronic sinus infection had tuberculosis-like organisms (mycobacteria) in their sinuses and that the same organisms were also in the tap water at their homes. These mycobacteria can be resistant to commonly used antimicrobial drugs. Doctors should check for mycobacteria in patients with treatment-resistant sinus infection. Patients who flush their sinuses at home should use sterile saline, not tap water.

Symptoms of chronic rhinosinusitis (CRS) often persist despite treatment. Because nontuberculous mycobacteria (NTM) are resistant to commonly used antimicrobial drugs and are found in drinking water that patients may use for sinus irrigation, we investigated whether some CRS patients were infected with NTM in New York, New York, USA, during 2001–2011. Two approaches were chosen: 1) records of NTM-infected CRS patients were reviewed to identify common features of infection and Mycobacterium species; 2) samples from plumbing in households of 8 NTM-infected patients were cultured for NTM presence. In 3 households sampled, M. avium sharing rep-PCR and pulsed field gel electrophoresis fingerprints identified M. avium isolates clonally related to the patients’ isolates. We conclude that patients with treatment-resistant CRS may be infected with NTM and should have cultures performed for NTM so appropriate therapy can be instituted. In addition, the results suggest that CRS patients can be infected by NTM in their household plumbing.

Cutaneous manifestations of Mycobacterium gordonae infection described for the first time in Italy: a case report

INTRODUCTION

Mycobacterium gordonae is one of the least pathogenic of the mycobacteria. This pathogen may produce caseating or non-caseating granulomas, and skin lesions showing acute or chronic inflammation with scattered histiocytes and giant cells have been seen. The mortality rate is less than 0.1%. Mycobacterium gordonae may be a marker of severe immunosuppression in patients infected with human immunodeficiency virus.

CASE PRESENTATION

We report a case of Mycobacterium gordonae infection in an 86-year-old woman and discuss the problems inherent to the identification and treatment of this emerging pathogen. Mycobacterium gordonae strain we isolated was resistant to trimethoprim-sulfamethoxazole but sensitive to ciprofloxacin, and long term administration (six months) induced complete healing of the cutaneous abscesses.

CONCLUSION

Advanced laboratory diagnostic techniques have improved the isolation and identification of nontuberculous mycobacteria. The diagnosis requires a high index of clinical suspicion, as detection by conventional methods is difficult. To our knowledge, this patient is the first documented case of cutaneous infection from this pathogen in Italy.

Mycobacterium gordonae infection in a colony of African clawed frogs (Xenopus tropicalis)

Mycobacterium gordonae is an occasional human pathogen associated with cutaneous infections and nodular granulomatous skin lesions. A case of cutaneous nodular infection caused by M. gordonae in a colony of African clawed frogs ( Xenopus tropicalis) is described and confirms this organism to be an opportunistic frog pathogen.

Mycobacterium gordonae urinary infection in a renal transplant recipient

The authors present a case of urinary infection by a non-tuberculous mycobacteria (NTM) species, Mycobacterium gordonae, in a renal transplant recipient. A 29-year-old female patient had persistent sterile pyuria after her second kidney transplant. An NTM, M. gordonae, was isolated, and the patient was started on antituberculous treatment, with resolution of leukocyturia. Ureteral stenosis with hydronephrosis and deterioration of allograft function was diagnosed later on and, despite the introduction of intraureteral catheter and resolution of hydronephrosis, there was no recovery of baseline renal function. She ultimately resumed dialysis after a severe pyelonephritis. The authors discuss the problems of establishing diagnosis of infection (versus colonization) by NTM and highlight the difficulty of treating these infections, especially because of the possible interaction with immunosuppressant agents, facilitating anti-allograft immune response.

Isolamento de micobactérias não-tuberculosas em São José do Rio Preto entre 1996 e 2005

OBJETIVO: Estudar a ocorrência de micobactérias não-tuberculosas e a variabilidade das espécies isoladas na região atendida pelo Instituto Adolfo Lutz-Regional de São José do Rio Preto-no período entre 1996 e 2005, assim como mostrar a importância do diagnóstico laboratorial. MÉTODOS: A partir de amostras pulmonares e extrapulmonares, foi realizado o isolamento de micobactérias, e estas foram identificadas por métodos fenotípicos e pelo método molecular polymerase chain reaction-restriction enzyme analysis. RESULTADOS: Foram isoladas 317 cepas de micobactérias não-tuberculosas: complexo Mycobacterium avium, 182 (57,4%); M. gordonae, 33 (10,4%); M. fortuitum, 25(7,9%); M. chelonae, 8 (2,5%); complexo M. terrae, 8 (2,5%); M. kansasii, 7 (2,2%); e espécies menos freqüentes, 54 (17%). No período, foram caracterizados 72 casos (33,3%) de micobacterioses, de acordo com os critérios bacteriológicos estabelecidos pela American Thoracic Society (2007).Desses, complexo M. avium foi responsável por 56 casos, sendo que 29 (51,8%) foram caracterizados como doença disseminada. M. fortuitum foi responsável por 6 casos; M. gordonae, 3; M. chelonae, 2; M. abscessus, 1; M. kansasii, 1; M. intracellulare, 1; M. malmoense, 1; e Mycobacterium ssp., 1. CONCLUSÕES: Os resultados obtidos mostraram a importância do diagnóstico bacteriológico das micobacterioses, pois a identificação das espécies possibilita a introdução de um tratamento adequado precocemente.

Nontuberculous mycobacterial peritonitis in peritoneal dialysis patients

While nontuberculous mycobacterial peritonitis is uncommon among peritoneal dialysis (PD) patients, these infections have serious consequences. They present a significant diagnostic and therapeutic challenge for clinicians. Diagnosis can be delayed due to the slow growth rate of some mycobacterial species. These organisms can also be overlooked when adequate culture media are not used in the microbiological evaluation process. The choice of antimicrobial therapy depends upon isolation and speciation of the infecting Mycobacterium species, and prompt catheter removal is essential. Because serious intra-abdominal complications may follow infection, identifying patient risk factors for nontuberculous mycobacterial peritonitis and initiating prompt diagnosis and treatment are essential. We report three cases of peritonitis associated with Mycobacterium chelonae and Mycobacterium gordonae, each with a unique presentation, and discuss the appropriate diagnosis and treatment strategies for the management of PD-associated mycobacterial infections.

Pseudo-outbreak of Mycobacterium gordonae: usefulness of randomly amplified polymorphic DNA analysis to assess the clonality of the isolates

Mycobacterium gordonae was detected in 18 of 21 clinical samples processed during the same day from patients with clinical suspicion of tuberculosis. Randomly amplified polymorphic DNA (RAPD) analysis revealed that all the isolates generated an identical pattern with each of the five primers used, and that these patterns were different from those of epidemiologically non-related isolates of M. gordonae. M. gordonae was not detected in the distilled water used for the procedures, and following replacement of the commercial products and sterilisation of home-made reagents, no more isolates belonging to the same clone of M. gordonae were detected.

Heterogeneity of RNA polymerase gene (rpoB) sequences of Mycobacterium gordonae clinical isolates identified with a DNA probe kit and by conventional methods

In a previous study, we have evaluated genetic identification by using the rpoB gene, which was recently introduced by Kim et al. (J. Clin. Microbiol. 39:2102-2109, 2001; J. Clin. Microbiol. 37:1714-1720, 1999). In this process, we examined the rpoB gene heterogeneity of clinical isolates identified as Mycobacterium gordonae with the conventional biological and biochemical tests and/or a commercially available DNA probe kit. Sequencing of the rpoB gene of 34 clinical isolates revealed that M. gordonae clinical isolates were classified into four major clusters (A, B, C, and D). Interestingly, organisms belonging to cluster D (15 isolates) did not hybridize with M. gordonae ATCC 14470 and specifically possessed urease activity. Therefore, it could be considered to be a novel mycobacterium. The identification of M. gordonae is known to have ambiguous results sometimes. On the other hand, identification of clinical isolates seems to be inconvenient and unsuitable because of a more than 99% 16S rRNA gene similarity value between clusters. These findings suggest that the existence of M. gordonae-like mycobacteria that share similar biochemical and biological characteristics with the 16S rRNA gene of an M. gordonae type strain but less similarity at the genomic DNA level may have complicated the identification of M. gordonae in many laboratories. Furthermore, compared with hsp65 PCR restriction analysis (PRA), rpoB PRA would have the advantage of producing no ambiguous results because of the intracluster homogeneity of the rpoB gene. In this case, rpoB would provide clearer results than hsp65, even if PRA analysis was used. We demonstrated that these M. gordonae-like mycobacteria were easily distinguished by PRA of the rpoB sequence. Additionally, the significance of this M. gordonae-like cluster may help to establish the comparison between the M. gordonae isolates from a clinical specimen and an infectious process in a given patient and to determine the true incidence of infection with this microorganism.

Endemic contamination of clinical specimens by Mycobacterium gordonae

Contamination of clinical specimens by Mycobacterium gordonae is a significant endemic problem in many laboratories. To investigate this problem, 84 cases at 1 hospital were retrospectively identified during 20 months. The overall rate of specimen contamination was 2. 4%, and 72 of the contaminated specimens were respiratory. A case-control comparison showed that the risk of respiratory specimen contamination was significantly increased if the specimen was expectorated (odds ratio [OR], 3.62; 95% confidence interval [CI], 1. 36-9.50) or if the patient consumed fluids within 2 days before specimen collection (OR, 8.92; 95% CI, 1.40-71.20). Cultures of tap water, ice, and iced drinking water all yielded M. gordonae at 10(-2)-10(0) cfu/mL. A culture survey of consenting patients showed contamination of 8 (24%) of 34 sputum specimens collected immediately after a tap water mouth rinse. These findings demonstrate that endemic specimen contamination arises from mycobacteria in hospital tap water and provide a foundation for control efforts.

Clinical and chest radiographic findings among persons with sputum culture positive for Mycobacterium gordonae: a review of 19 cases

STUDY OBJECTIVES

To describe the clinical and radiographic findings associated with growth of Mycobacterium gordonae in cultured sputum and to determine the proportion of cases that fulfill criteria for nontuberculous mycobacterial pulmonary disease as established by the American Thoracic Society.

DESIGN

A retrospective review of charts and radiographs of all patients from whom M gordonae was isolated from sputum cultures between November 1996 and June 1998.

SETTING

University-affiliated Veterans Affairs hospital.

PATIENTS

Nineteen patients were identified with sputum culture positive for M gordonae. All patients had a chest radiograph within 1 month of sputum culture.

RESULTS

Sixteen patients (84%) had suppressed local and/or general immunity. Sixteen patients (84%) had respiratory symptoms, weight loss, fever, or night sweats as an indication for chest radiography. Seventeen patients (89%) had abnormal chest radiographs; however, no typical radiographic pattern was observed. No patient met diagnostic criteria for nontuberculous mycobacterial pulmonary disease as delineated by the American Thoracic Society. All patients with abnormal chest radiographs and/or respiratory symptoms ultimately had alternative explanations for their pulmonary disease.

CONCLUSIONS

There is a broad spectrum of chest radiographic findings among persons with sputum culture positive for M gordonae, arguing against the presence of a characteristic chest radiograph in this patient population. M gordonae is usually a nonpathogenic colonizing organism, even among persons with local or general immune suppression and abnormal chest radiograph findings.

Non-tuberculous mycobacterial infection in children with cancer

Reported here is the clinical presentation and management of patients with rapidly growing non-tuberculous mycobacterial infection diagnosed in a paediatric oncology unit. A retrospective analysis that correlated patient isolates with the children's cancer registry revealed two cases of non-tuberculous mycobacterial infection; both had been observed within the last 6 years and were due to Mycobacterium chelonae. The first case was line-associated and the second was a disseminated infection. In both cases the patients were lymphopenic and had had indwelling vascular catheters. Neither patient was neutropenic. The literature on mycobacterial infection in children with cancer is also reviewed.