Mycobacterium Immunogenum Research Articles

T-cell antigens of Mycobacterium immunogenum, an etiological agent of occupational hypersensitivity pneumonitis.

The T lymphocyte-mediated immune lung disease hypersensitivity pneumonitis (HP) in machinists is poorly understood for disease mechanisms and diagnosis due in part to lack of information on causative T-cell antigens of the etiological agent Mycobacterium immunogenum (MI). Therefore, overall objective of the current study was to identify T-cell reactive antigens of this recently recognized pathogen. In this direction, purified recombinant form of five of the seroreactive proteins (reported in our initial study), including three cell wall-associated (arbitrarily designated as antigens A through C) and two secretory (AgD & AgE), were examined for their potential to activate antigen-presenting cells (APCs) viz. alveolar macrophages and human monocyte-derived dendritic cells (DCs) and for T-cell reactivity. All five proteins strongly activated APCs by inducing inflammatory cytokines (TNF-α, IL-6 & IL-1α) and nitric oxide (NO), albeit to a varying extent (AgE≥AgD>AgB≥AgA≥AgC), implying their differential potential for activation of APCs. However, only two of the five proteins (AgA, AgD) showed significant T-cell response (T lymphocyte proliferation and IFN-γ secretion) when tested using sensitized T-cells from MI-induced HP mouse model. These antigens also activated the human naïve CD4(+) T cells in presence of autologous DCs as measured using ELISPOT for IFN-γ. Immuno-informatic analysis predicted that the identified T-cell antigens (AgA and AgD) bind more number of class I and class II HLA alleles as compared with the reference immuno-dominant antigens ESAT-6 and CFP-10 from the tuberculous mycobacterial species M. tuberculosis. Predicted human population coverage for the epitopes of AgA (90.87%) and AgD (88.09%) was also higher as compared to those for the reference antigens ESAT-6 (82.42%) and CFP-10 (80.21%). These two antigens were further predicted to be highly immunogenic for class I peptide MHC (pMHC) complex as compared to the reference antigens. Collectively, our results imply that AgA and AgD are T-cell antigens with a high HLA binding frequency as well as population coverage for HLA alleles. This first report on T-cell antigens and epitopes of M. immunogenum is significant as it is expected to open up avenues for understanding pathogenesis mechanisms and developing T-cell-based immunodiagnostic tools for this poorly investigated occupational lung disease.

Epidemiology of Rapidly Growing Mycobacteria Bloodstream Infections

BackgroundRapidly growing mycobacteria (RGM) bloodstream infections (BSI) are an emerging problem often associated with therapeutic challenges. We review the epidemiology, treatment and outcomes over a 5-year period of a heterogeneous group presenting to our institution with RGM BSI. Materials and MethodsA retrospective cohort study of patients with primary RGM BSI from January 2006-December 2011 was conducted. Patient characteristics (age, race, sex and comorbidities), infection characteristics (catheter associated, hospital acquired, microbiology and antimicrobial susceptibilities), therapy and outcomes were recorded and compared by species. ResultsAmong 32 patients, 33 RGM BSI occurred. Patients had an average of 3-4 comorbidities, most commonly malignancy (45.5%). Most isolates (30.3%) were Mycobacterium fortuitum or Mycobacterium mucogenicum (27.2%), followed by Mycobacterium abscessus/chelonae (18.2%) and Mycobacterium immunogenum (12.2%). In all, 85% were catheter associated and 27.3% were hospital acquired. Empiric therapy was started in 19 (57.6%) patients and among these, it was adequate (at least 2 active agents based on susceptibilities) in 12 (63.2%). Among 21 patients with outcome data, cure was assumed for 14 (66.7%). One death was attributable to RGM BSI. Cure rates were higher among those who received adequate empiric therapy compared to those who did not (83.3% versus 42.9%). In general, antibiotic susceptibility was favorable across species for clarithromycin, amikacin and imipenem. ConclusionsRGM BSI occurred in a population with multiple comorbidities, most commonly malignancy, and most were catheter associated. Higher cures were seen among those who received adequate empiric therapy and based on susceptibility data, a broad empiric regimen of clarithromycin, amikacin and imipenem would be expected to be adequate.

Draft Genome Sequences of Six Mycobacterium immunogenum Strains Obtained from a Chloraminated Drinking Water Distribution System Simulator.

We report here the draft genome sequences of six Mycobacterium immunogenum strains isolated from a chloraminated drinking water distribution system simulator subjected to changes in operational parameters. M. immunogenum, a rapidly growing mycobacterium previously reported to be the cause of hypersensitivity pneumonitis from contaminated metalworking fluid aerosols, is becoming a public health concern.

A Case Series Review of Mycobacterium immunogenum Infection at an Academic Medical Center

A Case Series Review of Mycobacterium immunogenum Infection at an Academic Medical Center

Mycobacterium saopaulense sp. nov., a rapidly growing mycobacterium closely related to members of the Mycobacterium chelonae--Mycobacterium abscessus group.

Five isolates of non-pigmented, rapidly growing mycobacteria were isolated from three patients and,in an earlier study, from zebrafish. Phenotypic and molecular tests confirmed that these isolates belong to the Mycobacterium chelonae-Mycobacterium abscessus group, but they could not be confidently assigned to any known species of this group. Phenotypic analysis and biochemical tests were not helpful for distinguishing these isolates from other members of the M. chelonae–M.abscessus group. The isolates presented higher drug resistance in comparison with other members of the group, showing susceptibility only to clarithromycin. The five isolates showed a unique PCR restriction analysis pattern of the hsp65 gene, 100 % similarity in 16S rRNA gene and hsp65 sequences and 1-2 nt differences in rpoB and internal transcribed spacer (ITS) sequences.Phylogenetic analysis of a concatenated dataset including 16S rRNA gene, hsp65, and rpoB sequences from type strains of more closely related species placed the five isolates together, as a distinct lineage from previously described species, suggesting a sister relationship to a group consisting of M. chelonae, Mycobacterium salmoniphilum, Mycobacterium franklinii and Mycobacterium immunogenum. DNA–DNA hybridization values .70 % confirmed that the five isolates belong to the same species, while values ,70 % between one of the isolates and the type strains of M. chelonae and M. abscessus confirmed that the isolates belong to a distinct species. The polyphasic characterization of these isolates, supported by DNA–DNA hybridization results,demonstrated that they share characteristics with M. chelonae–M. abscessus members, butconstitute a different species, for which the name Mycobacterium saopaulense sp. nov. is proposed. The type strain is EPM10906T (5CCUG 66554T5LMG 28586T5INCQS 0733T).

Molecular characterization of microbial communities and quantification of Mycobacterium immunogenum in metal removal fluids and their associated biofilms.

A number of human health effects have been associated with exposure to metal removal fluids (MRFs). Multiple lines of research suggest that a newly identified organism, Mycobacterium immunogenum (MI), appears to have an etiologic role in hypersensitivity pneumonitis (HP) in case of MRFs exposed workers. However, our knowledge of this organism, other possible causative agents (e.g., Pseudomonads), and the microbial ecology of MRFs in general, is limited. In this study, culture-based methods and small subunit ribosomal RNA gene clone library approach were used to characterize microbial communities in MRF bulk fluid and associated biofilm samples collected from fluid systems in an automobile engine plant. PCR amplification data using universal primers indicate that all samples had bacterial and fungal contaminated. Five among 15 samples formed colonies on the Mycobacteria agar 7H9 suggesting the likely presence of Mycobacteria in these five samples. This observation was confirmed with PCR amplification of 16S rRNA gene fragment using Mycobacteria specific primers. Two additional samples, Biofilm-1 and Biofilm-3, were positive in PCR amplification for Mycobacteria, yet no colonies formed on the 7H9 cultivation agar plates. Real-time PCR was used to quantify the abundance of M. immunogenum in these samples, and the data showed that the copies of M. immunogenum 16S rRNA gene in the samples ranges from 4.33 × 10(4) copy/ml to 4.61 × 10(7) copy/ml. Clone library analysis revealed that Paecilomyces sp. and Acremonium sp. and Acremonium-like were dominant fungi in MRF samples. Various bacterial species from the major phylum of proteobacteria were found and Pseudomonas is the dominant bacterial genus in these samples. Mycobacteria (more specifically MI) were found in all biofilm samples, including biofilms collected from inside the MRF systems and from adjacent environmental surfaces, suggesting that biofilms may play an important role in microbial ecology in MRFs. Biofilms may provide a shield or sheltered microenvironment for the growth and/or colonization of Mycobacteria in MRFs.

Novel antigens of Mycobacterium immunogenum relevant in serodiagnosis of occupational hypersensitivity pneumonitis in machinists

Novel antigens of Mycobacterium immunogenum relevant in serodiagnosis of occupational hypersensitivity pneumonitis in machinists

Microbial contamination and biofilms on machines of metal industry using metalworking fluids with or without biocides

Microbial contamination is commonly found in metalworking fluids (MWFs) used in metal manufacturing industry. The aim of this study was to determine whether the use of MWF containing a biocide reduces the growth and influences the biofilm-forming capacity of microorganisms from field coolants, thereby efficiently protecting MWFs from biodeterioration. Overall, 164 bacterial strains classified into 40 species were collected from 69 machines in ten plants visited. Among them, Comamonas testosteroni was the most numerous species, and Pseudomonas was the most abundant genus. The isolation of Mycobacterium immunogenum was done from MWF for the first time in Poland. The number of bacteria in MWFs and size of microbial populations in biofilms were not affected by the presence of biocides in the industrial samples. In MWFs contaminated with microorganisms with the highest biofilm-forming capacity, several species of Enterobacteriaceae were identified. The proper management of MWF delivery systems is required to control biofilm development even when MWFs containing biocides are used. Moreover, good hygiene practices are needed to prevent the metal working machines from biofilms. This case study can help in appropriate monitoring the MWF distribution systems vulnerable to microbial colonization in metal industry.

Absence of a functional erm gene in isolates of Mycobacterium immunogenum and the Mycobacterium mucogenicum group, based on in vitro clarithromycin susceptibility.

Macrolide resistance has been linked to the presence of a functional erythromycin ribosomal methylase (erm) gene in most species of pathogenic rapidly growing mycobacteria (RGM). For these Mycobacterium isolates, extended incubation in clarithromycin is necessary to determine macrolide susceptibility. In contrast, the absence of a detectable erm gene in isolates of M. chelonae, M. senegalense, and M. peregrinum and a nonfunctional erm gene in M. abscessus subsp. massiliense and 15% to 20% of M. abscessus subsp. abscessus isolates renders these species intrinsically macrolide susceptible. Not all RGM species have been screened for the presence of an erm gene, including the Mycobacterium mucogenicum group (M. mucogenicum, M. phocaicum, and M. aubagnense) and Mycobacterium immunogenum. A total of 356 isolates of these two pathogenic RGM taxa from two reference laboratories (A.R.U.P. Reference Laboratories and the Mycobacteria/Nocardia Laboratory at the University of Texas Health Science Center at Tyler) underwent clarithromycin susceptibility testing with readings at 3 to 5 days and 14 days. Only 13 of the 356 isolates had resistant clarithromycin MICs at initial extended MIC readings, and repeat values on all available isolates were ≤2 μg/ml. These studies suggest that these two additional RGM groups do not harbor functional erm genes and, like M. chelonae, do not require extended clarithromycin susceptibility testing. We propose to the Clinical Laboratory and Standards Institute that isolates belonging to these above-mentioned six rapidly growing mycobacterial groups based on molecular identification with no known functional erm genes undergo only 3 to 5 days of susceptibility testing (to exclude mutational resistance).

Alveolar Macrophage Innate Response to Mycobacterium immunogenum, the Etiological Agent of Hypersensitivity Pneumonitis: Role of JNK and p38 MAPK Pathways

Mycobacterium immunogenum is an emerging pathogen of the immune-mediated lung disease hypersensitivity pneumonitis (HP) reported in machinists occupationally exposed to contaminated metal working fluid (MWF). However, the mechanism of its interaction with the host lung is unclear. Considering that alveolar macrophages play a central role in host defense in the exposed lung, understanding their interaction with the pathogen could provide initial insights into the underlying immunopathogenesis events and mechanisms. In the current study, M. immunogenum 700506, a predominant genotype isolated from HP-linked fluids, was shown to multiply intracellularly, induce proinflammatory mediators (TNF-α, IL-1α, IL-1β, IL-6, GM-CSF, NO) and cause cytotoxicity/cell death in the cultured murine alveolar macrophage cell line MH-S in a dose- and time-dependent manner. The responses were detected as early as 3h post-infection. Comparison of this and four additional genotypes of M. immunogenum (MJY-3, MJY-4, MJY-12, MJY-14) using an effective dose-time combination (100 MOI for 24h) showed these macrophage responses in the following order (albeit with some variations for individual response indicators). Inflammatory: MJY-3 ≥ 700506 > MJY-4 ≥ MJY-14 ≥ MJY-12; Cytotoxic: 700506 ≥ MJY-3 > MJY-4 ≥ MJY-12 ≥ MJY-14. In general, 700506 and MJY-3 showed a more aggressive response than other genotypes. Chemical blocking of either p38 or JNK inhibited the induction of proinflammatory mediators (cytokines, NO) by 700506. However, the cellular responses showed a somewhat opposite effect. This is the first report on M. immunogenum interactions with alveolar macrophages and on the identification of JNK- and p38- mediated signaling and its role in mediating the proinflammatory responses during these interactions.

External validation of recombinant antigens for serodiagnosis of machine operator's lung

Machine operator's lung (MOL) is a hypersensitivity pneumonitis the diagnosis of which is difficult. Our laboratory previously developed an ELISA test using recombinant antigens from Mycobacterium immunogenum isolated in French plant. The objective was to validate the previous ELISA results with ten new suspected cases from Germany. Two serological analyses were performed: ELISA with the six recombinant antigens, and electrosyneresis with crude antigens of M. immunogenum and three other main species isolated from contaminated metalworking fluids. The two recombinant antigens acyl-CoA dehydrogenase and dihydrolipoyl dehydrogenase, combined together, and electrosyneresis are useful in making the diagnosis regardless of the clinical and radiological data. Finally 9 out of the 10 suspected cases were declared as MOL. Despite the geographical distance, the crude and recombinant antigens produced to investigate the clustered French cases also proved to be useful in diagnosing the suspected cases in Germany.

Human Monocyte-Derived Dendritic Cells Exposed to Microorganisms Involved in Hypersensitivity Pneumonitis Induce a Th1-Polarized Immune Response

ABSTRACTHypersensitivity pneumonitis (HP) is an immunoallergic disease characterized by a prominent interstitial infiltrate composed predominantly of lymphocytes secreting inflammatory cytokines. Dendritic cells (DCs) are known to play a pivotal role in the lymphocytic response. However, their cross talk with microorganisms that cause HP has yet to be elucidated. This study aimed to investigate the initial interactions between human monocyte-derived DCs (MoDCs) and four microorganisms that are different in nature (Saccharopolyspora rectivirgula[actinomycetes],Mycobacterium immunogenum[mycobacteria], andWallemia sebiandEurotium amstelodami[filamentous fungi]) and are involved in HP. Our objectives were to determine the cross talk between MoDCs and HP-causative agents and to determine whether the resulting immune response varied according to the microbial extract tested. The phenotypic activation of MoDCs was measured by the increased expression of costimulatory molecules and levels of cytokines in supernatants. The functional activation of MoDCs was measured by the ability of MoDCs to induce lymphocytic proliferation and differentiation in a mixed lymphocytic reaction (MLR).E. amstelodami-exposed (EA) MoDCs expressed higher percentages of costimulatory molecules than didW. sebi-exposed (WS),S. rectivirgula-exposed (SR), orM. immunogenum-exposed (MI) MoDCs (P< 0.05, Wilcoxon signed-rank test). EA-MoDCs, WS-MoDCs, SR-MoDCs, and MI-MoDCs induced CD4+T cell proliferation and a Th1-polarized immune response. The present study provides evidence that, although differences were initially observed between MoDCs exposed to filamentous fungi and MoDCs exposed to bacteria, a Th1 response was ultimately promoted by DCs regardless of the microbial extract tested.

Safety of Injecting Insulin Through Clothes: A Case of Mycobacterium immunogenum Cutaneous Infection and Review of the Literature

L.S., a 47-year-old white woman with type 1 diabetes, a bleeding diathesis, and iron deficiency anemia, was referred to an infectious diseases physician for assessment of a painful, nonhealing skin lesion. Before the referral, her primary care physician had treated her with several courses of oral antibiotics, including cephalexin, clindamycin, and amoxicillin, without improvement. She denied a history of preceding trauma, recent foreign travel, or exposure to aquatic animals or hot tubs. When questioned about whether the lesion was at the site of insulin injection, she stated this was possible because she had injected insulin at various locations through her clothes since adolescence, as instructed. On physical examination, the patient appeared well. Her skin examination was significant for a 5-cm erythematous, tender nodule on the anteromedial aspect of her right thigh (Figure 1). No drainage from the lesion or evidence of surrounding cellulitis was found. There was no associated lymphadenopathy, and the remainder of her physical examination was unremarkable. Routine laboratory tests, including leukocyte count with differential, platelets, electrolytes, creatinine, and liver enzymes, were within normal ranges. Her A1C was elevated at 10.8%. Histology of the biopsied lesion demonstrated nonspecific inflammation with negative stains for acid-fast bacilli (AFB) and fungi. Cultures, however, were positive for mycobacteria spp. after an extended incubation period of 63 days (compared to the conventional incubation period of 49 days). 16S rRNA sequencing identified the organism as Mycobacterium immunogenum . The antimicrobial agents the organism was susceptible to were limited to clarithromycin and tigecycline, with intermediate sensitivity to amikacin. The organism was resistant to ciprofloxacin, doxycycline, cefoxitin, imipenem, cotrimoxazole, and linezolid. 1. How did this …

Disseminated Mycobacterium immunogenum infection presenting with septic shock and skin lesions in a renal transplant recipient

Mycobacterium immunogenum is a relatively new species within the Mycobacterium chelonae-Mycobacterium abscessus group of rapidly growing mycobacteria (RGM). M. immunogenum was first characterized in 2001 and, similar to other RGM, is an ubiquitous environmental organism. This organism has most commonly been implicated in cutaneous infection in both healthy and immunosuppressed patients. To our knowledge, this is the first reported case of septic shock in the setting of disseminated M. immunogenum infection. Definitive identification of this organism requires gene sequencing at specialized centers, which may limit its detection. M. immunogenum is resistant to many anti-mycobacterial agents, and treatment can be especially challenging in transplant patients, given potential drug interactions and added toxicities. It is important to distinguish M. immunogenum from other RGM and determine the susceptibility profile to devise a successful treatment plan, particularly in the transplant population in which it can potentially cause severe, disseminated disease.

A biocide-free mineral oil nanoemulsion exhibiting strong bactericidal activity against Mycobacterium immunogenum and Pseudomonas aeruginosa

Mycobacterium immunogenum and Pseudomonas aeruginosa currently present one of the highest health concerns in metalworking processes. The former is a Gram positive bacterium strongly associated with hypersensitivity pneumonitis outbreaks and the latter is a Gram negative famous for its opportunistic pathogenesis and frequent isolation from in-service metalworking fluids (MWFs). Thus far, biocide addition is the only microbial control measure in MWFs, but it often fails on preventing mycobacteria proliferation. This study aimed to formulate an inherently bacteria-resistant MWF with industrial grade chemicals. Using a phase inversion temperature method, we created a low-cost mineral oil nanoemulsion (MONE) which has extraordinarily high bactericidal activity against M. immunogenum and P. aeruginosa and has the smallest oil droplet size ever reported in the literature. A short-term biocidal test showed that a 5% dilution of MONE (5% MONE) exhibited high emulsion stability and strong bactericidal effects. The first-order biocidal rate constants of 5% MONE are higher than 72% of the 32 different test combinations of commercially available MWFs amended with two industrial biocides, KATHON™ LXE and Preventol® CMK-NA. A further longer term test on an aged 5% MONE showed it achieved 100% elimination of all tested bacteria either in pure cultures or a mixed culture up to 28 days. The biocidal kinetics of MONE seemed to follow a new equation, ln(N/N0)=−k0’(exp(n’C))t, much better than the currently most widely accepted Chick–Watson law equation. Among the reported antimicrobial nanomaterials and industrial biocides, this nanoemulsion formulation may offer a low-cost solution in sustainable utilization of mineral oil in MWF applications and a new research perspective on biodeterioration prevention of MWFs.

Hsp65 PCR-restriction analysis (PRA) with capillary electrophoresis for species identification and differentiation of Mycobacterium kansasii and Mycobacterium chelonae–Mycobacterium abscessus group

The aim of the present study was to identify and differentiate Mycobacterium kansasii and Mycobacterium chelonae-Mycobacterium abscessus group strains isolated from clinical and environmental sources in different countries. PCR-restriction analysis of the hsp65 gene (PRA) with automated capillary electrophoresis was applied to the isolates previously identified by conventional biochemical testing and the molecular INNO-LiPA MYCOBACTERIA assay. PRA performed very well in comparison with the two other methods (96.4% concordance). Among 27 M. kansasii isolates, this method detected five genetic types, of which type 1 represented the most common clinical isolate, as it is worldwide. PRA differentiated 29 M. chelonae-M. abscessus group isolates into Mycobacterium immunogenum type 2 (n=13), M. chelonae (n=12), and M. abscessus types 1 (n=1) and 2 (n=1). M. immunogenum was the most frequent (69%) isolate from humans, but only one of 11 cases was clinically significant. M. chelonae was the most commonly (83%) recovered from water. PRA also identified two isolates with hsp65 alleles representing previously unreported patterns. PRA based on automated capillary electrophoresis is a rapid, simple, and reliable method for the identification and differentiation of both clinically relevant and environmental isolates of M. kansasii and M. chelonae-M. abscessus group.

Expanding the mycobacterial diversity of metalworking fluids (MWFs): evidence showing MWF colonization by Mycobacterium abscessus

Nontuberculous mycobacteria (NTM) have been associated with hypersensitivity pneumonitis in machinists. Only two species of NTM, namely Mycobacterium immunogenum and Mycobacterium chelonae, have been reported thus far to have the ability to colonize contaminated metalworking fluids (MWFs). Here, we report, for the first time, the presence and characterization (phenotypic and genotypic) of a third species, Mycobacterium abscessus, colonizing these harsh alkaline machining fluids. Two Mycobacterium morphotypes, smooth (S) and rough (R), were isolated (two isolates each) from an in-use industrial MWFs. Biocide susceptibility analysis using triclosan as a model yielded the same minimal inhibitory concentration for the two morphotypes. PCR-restriction analysis-based speciation of the morphotypes confirmed their identity as M. abscessus. Genotyping based on partial DNA sequences corresponding to the variable regions of the hsp65 gene and 16S-23S rRNA operon internal transcribed spacer region and randomly amplified polymorphic DNA-PCR analysis showed that both morphotypes belong to a single genotype. In addition, we isolated and confirmed two novel mycobacterial genotypes, one each of M. immunogenum and M. chelonae from additional in-use MWF screening. Taken together, this study expands the known mycobacterial species- and strain-diversity colonizing MWF. Furthermore, the study emphasizes the need for including M. abscessus species in the existing mycobacterial screening of contaminated MWF.

Surface properties and water treatment capacity of surface engineered silica coated with 3-(2-aminoethyl) aminopropyltrimethoxysilane

This study's focus was on the water-based, one-pot preparation and characterisation of silica particles coated with 3-(2-aminoethyl)aminopropyltrimethoxysilane (Diamo) and the efficiency of the material in removing the pathogens Escherichia coli, Pseudomonas aeruginosa, Mycobacterium immunogenum, Vibrio cholerae, poliovirus, and Cryptosporidium parvum. The water-based processing resulted in Diamo coated silica particles with significantly increased positive surface charge as determined by zeta potential measurements. In addition, X-ray photoelectron spectrometry of pure and Diamo coated silica confirmed the presence of Diamo on the surface of the particles. Thermogravimetric measurements and chemical analysis of the silica indicated a surface concentration of amine groups of about 1mmol/gsilica. Water treatment tests with the pathogens showed that a dose of about 10g appeared to be sufficient to remove pathogens from pure water samples which were spiked with pathogen concentrations between about 102 and 104cfu/mL.

Implementation of a Quantitative Real-Time PCR Assay for the Detection of Mycobacterium immunogenum in Metalworking Fluids

The bacterium Mycobacterium immunogenum has been implicated in causing the lung condition hypersensitivity pneumonitis (HP) in factory workers exposed to colonized metalworking fluids (MWFs). M. immunogenum-specific, real-time quantitative PCR detection technique (MiRT-qPCR) was implemented on a large scale to 363 MWFs of varying types, originating from the United States and Europe, that had been in use for between 30 days and 1 year. In MWFs that contained between 103 and 109 culturable general heterotrophs mL−1 the technique detected between 5 and 2 × 106 mL−1 M. immunogenum cell equivalents (CE) in 12.2% (23 of 189) of U.S. samples and between 8 and 6 × 105 mL−1 CE in 39.1% (68 of 174) of samples from Europe. In contrast, only three cultured presumptive mycobacterial isolates across all samples were confirmed as M. immunogenum. Implementation of the assay demonstrated its practicality and further emphasized the limitations of using cultivation alone. Interestingly, no M. immunogenum were detected in mineral oil-based Bio-Concept MWFs from the United States, while it was more commonly detected in used MWFs based on formaldehyde-releasing biocides than in MWFs free of formaldehyde-depot biocides.

Investigation of an Outbreak of SSI Due to Mycobacterium immunogenum after Blepharoplasty

Investigation of an Outbreak of SSI Due to Mycobacterium immunogenum after Blepharoplasty