Successful bedaquiline-containing antimycobacterial treatment in post-traumatic skin and soft-tissue infection by Mycobacterium fortuitum complex: a case report.

BACKGROUND: Mycobacterium fortuitum complex is a group of rapidly growing nontuberculous mycobacteria (NTM) associated with skin and soft-tissue infections after surgery or trauma. Treatment of NTM is challenging, due to resistance to multiple antimycobacterial agents. Bedaquiline is a diarylquinoline that inhibits mycobacterial ATP-synthase. The drug has recently been approved for the treatment of multidrug-resistant tuberculosis and evidence of its in vitro efficacy against NTM, including Mycobacterium fortuitum complex, has been published. CASE PRESENTATION: A 20-year-old Caucasian woman with chronic skin and soft tissue infection in the lower leg following a traffic accident in Vietnam underwent a tedious journey of healthcare visits, hospital admissions, empiric antimicrobial treatments, surgical debridement and plastic reconstruction before definite diagnosis of Mycobacterium fortuitum complex-infection was established by culture from a tissue biopsy and targeted antimycobacterial therapy was administered. Histopathological examination revealed granulomatous purulent inflammation, which strongly supported the diagnosis. Genotypic identification was performed and broth microdilution for susceptibility testing showed macrolide resistance. Five weeks of induction treatment with intravenous amikacin, imipenem / cilastin, and oral levofloxacin was administered, followed by all-oral treatment with bedaquiline combined with levofloxacin for four months, which was well-tolerated and led to persistent healing with scars but without signs of residual infection. CONCLUSIONS: Bedaquiline is a promising novel agent for NTM treatment, although clinical data are limited and trials evaluating efficacy, safety, and resistance of bedaquiline are required. To our knowledge, this is the first reported case of successful in vivo use of bedaquiline for a skin and soft tissue infection caused by Mycobacterium fortuitum complex.

Preliminary evaluation of the positively and negatively charge effects of tetra-substituted porphyrins on photoinactivation of rapidly growing mycobacteria.

This manuscript reports, at the first time, the photoinactivation evaluation of tetra-cationic and anionic porphyrins as photosensitizers (PS) for the photodynamic inactivation (PDI) of rapidly growing mycobacteria strains. Two different charged porphyrin groups were obtained commercially. PDI experiments in the strains Mycobacterium massiliense e Mycobacterium fortuitum conducted with adequate concentration (without aggregation) of photosensitizer under white light at a fluence rate of 50 mW/cm2 over 90 min showed that the most effective PS caused a 100 times reduction in the concentration of viable mycobacteria. The present results show that porphyrin with positively charge are more efficient PS than anionic porphyrin (negatively charged) against M. massiliense e M. fortuitum. It is also clear that the effectiveness of the molecule as PS for PDI studies with mycobacteria is strongly related with the porphyrin peripheral charge, and consequently their solubility in physiological media. Cationic PSs might be promising anti-mycobacteria PDI agents with potential applications in medical clinical cases and bioremediation.

Repurposing disulfiram to target infections caused by non-tuberculous mycobacteria.

BACKGROUND: Non-tuberculous mycobacteria are emerging pathogens of significant worldwide interest because they have inherent drug resistance to a wide variety of FDA-approved drugs and cause a broad range of serious infections. In order to identify new drugs active against non-tuberculous mycobacteria, we identified disulfiram, utilized for treatment of alcohol dependence, as exhibiting potent growth-inhibitory activity against non-tuberculous mycobacteria. METHODS: Whole-cell growth inhibition assays were used to screen and identify novel inhibitors. The hit compounds were tested against Vero cells to determine the selectivity index, and this was followed by determining time-kill kinetics against Mycobacterium fortuitum and Mycobacterium abscessus. Disulfiram's ability to synergize with several approved drugs utilized for the treatment of M. fortuitum and M. abscessus was determined using fractional inhibitory concentration indexes followed by determining its ability to reduce mycobacterial infections ex vivo. Finally, disulfiram's in vivo potential was determined in a neutropenic murine model mimicking mycobacterial infection. RESULTS: We identified disulfiram as possessing potent antimicrobial activity against non-tuberculous mycobacteria. Disulfiram exhibited concentration- and time-dependent bactericidal activity against M. fortuitum as well as against M. abscessus and synergized with all drugs utilized for their treatment. Additionally, disulfiram reduced bacterial load in macrophages in an intracellular killing assay better than amikacin. When tested in a murine neutropenic M. fortuitum infection model, disulfiram caused significant reduction in bacterial load in kidneys. CONCLUSIONS: Disulfiram exhibits all properties required for it to be repositioned as a novel anti-mycobacterial therapy and possesses a potentially new mechanism of action. Thus, it can be considered as a potent structural lead for the treatment of non-tuberculous mycobacterial infections.

Efficacy of calcium hypochlorite and ultraviolet irradiation against Mycobacterium fortuitum and Mycobacterium marinum.

BACKGROUND: Nontuberculous mycobacteria (NTM) cause opportunistic infections with increasing frequency in immunocompromised humans. Water is one of the natural sources for transmission of NTM and plays a major role in the epidemiology of NTM infections. This study evaluated the efficacy of calcium hypochlorite and ultraviolet irradiation (UV) to eliminate potentially zoonotic NTM species such as M. marinum and M. fortuitum. MATERIALS AND METHODS: Bacterial suspensions containing1-4 × 105 CFU/ml were exposed to 5, 50, 100, 1,000 and 10,000 mg/L of Ca (OCl)2for 1, 5, 10, 15, 20, 30 and 60 minutes, and 6,000 µW/cm2 UV dose for 5, 10, 20, 30, 60 and 120 seconds. RESULTS: Of the two methods tested, UV irradiation was more effective than chlorine in achieving three log reduction in viable bacterial count (UV dose 6,000 µW/cm2, exposure time 60 S) as well as in eliminating the organisms (UV dose 17,000 µW/cm2, exposure time: 30 S). When 10,000 mg/L of chlorine was used, 10 and 20 min contact times were required to achieve three log inactivation and complete elimination of M. fortuitum respectively. CONCLUSION: Our study suggest that initial disinfection of water by chlorine at the water treatment plant followed by UV irradiation at the household level would minimise the spread of NTM to the susceptible population via drinking water.

Port-site infections by nontuberculous mycobacterium: A retrospective clinico-microbiological study.

BACKGROUND: Port-site infection (PSI) is a prevailing, chronic, nagging, treatment refractory complication of laparoscopic surgery (LS). It neutralizes the advantages of minimally invasive surgery and increases morbidity, treatment cost of patient, leading to loss of confidence on operating surgeon. PSIs are preventable with appropriate preoperative, intraoperative, and postoperative measures. Atypical mycobacterium is most commonly associated with nonhealing postlaparoscopic wound infections, causing outbreaks or sporadic cases worldwide. PURPOSE: We retrospectively studied the occurrence of nontuberculous mycobacterium (NTM) from PSIs following LS that did not respond to antibiotics used for pyogenic infections and having sterile routine aerobic cultures and their antimicrobial susceptibility pattern to guide proper management. METHODS: The study was done in a tertiary care hospital of Eastern India over a 1-year period which included PSI cases with delayed onset not responding to antibiotics, following different types of LS. Pus/discharge from 32 patients was collected and examined for isolation and identification of the causative agents. Gram stain and Ziehl-Neelsen staining methods were used for direct examination. Culture media included blood agar, Robertson's cooked meat broth, MacConkey agar, and Lowenstein-Jensen medium. Isolates from the cases were identified using biochemical tests or molecular methods and studied the antimicrobial susceptibility pattern by the standard microbiologic procedures. RESULTS: Mycobacterium abscessus (13) and Mycobacterium fortuitum (2) were isolated from 15 serosanguinous drainage obtained from 32 cases by routine microbiological techniques. All isolates analyzed for antimicrobial susceptibility pattern were highly sensitive to clarithromycin (93.3%), amikacin (93.3%), and imipenem (80%) but were variable to ciprofloxacin, ofloxacin, and linezolid. CONCLUSIONS: Our present study shows frequent association of NTM with laparoscopic port-site nonhealing chronic infection or wound dehiscence. Although direct microscopy can give us a clue to diagnosis, culture isolation is required for speciation and antimicrobial susceptibility testing, which helps formulate therapeutic regimen.

Epidemiology of Rapidly Growing Mycobacteria Bloodstream Infections.

BACKGROUND: Rapidly 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 METHODS: A 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. RESULTS: Among 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. CONCLUSIONS: RGM 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.

Biofilms of Pathogenic Nontuberculous Mycobacteria Targeted by New Therapeutic Approaches.

Microbial infections of the cornea are potentially devastating and can result in permanent visual loss or require vision-rescuing surgery. In recent years, there has been an increasing number of reports on nontuberculous mycobacterial infections of the cornea. Challenges to the management of nontuberculous mycobacterial keratitis include delayed laboratory detection, low index of clinical suspicion, poor drug penetration, slow response to therapy, and prolonged use of antibiotic combinations. The ability of nontuberculous mycobacteria to evade the host immune response and the ability to adhere and to form biofilms on biological and synthetic substrates contribute to the issue. Therefore, there is an urgent need for new antimicrobial compounds that can overcome these problems. In this study, we evaluated the biofilm architectures for Mycobacterium chelonae and Mycobacterium fortuitum in dynamic flow cell chamber and 8-well chamber slide models. Our results showed that mycobacterial biofilms were quite resistant to conventional antibiotics. However, DNase treatment could be used to overcome biofilm resistance. Moreover, we successfully evaluated a new antimicrobial compound (AM-228) that was effective not only for planktonic mycobacterial cells but also for biofilm treatment and was compared favorably with the most successful "fourth-generation" fluoroquinolone, gatifloxacin. Finally, a new treatment strategy emerged: a combination of DNase with an antibiotic was more effective than an antibiotic alone.

Localized cutaneous infections in immunocompetent individuals due to rapidly growing mycobacteria.

Rapidly growing mycobacteria (RGM) cause skin infections that are refractory to standard antibiotic regimens. Although typically associated with disseminated cutaneous or other systemic infections in immunocompromised patients, RGM sometimes cause localized cutaneous infections in immunocompetent hosts. These infections are almost always associated with precedent skin trauma and inoculation, and therefore have been implicated in outbreaks involving contaminated tattoo ink and inadequately sterilized acupuncture needles. Histologic features often include suppurative granulomatous inflammation, and microorganisms are rarely visualized with stains for acid-fast bacilli. The differential diagnosis includes granulomatous fungal and non-RGM bacterial infections as well as noninfectious suppurative or sarcoidlike conditions. Because no pathognomonic histologic features exist for cutaneous RGM infections, clinical suspicion and appropriate workup are essential to reach an accurate and timely diagnosis. Most localized cutaneous RGM infections in immunocompetent individuals respond well to either clarithromycin or amikacin, in combination with surgical debridement.

Dual infection by streptococcus and atypical mycobacteria following Ahmed glaucoma valve surgery.

PURPOSE: To report a case of late postoperative endophthalmitis caused by Streptococcus pneumoniae and conjunctival necrosis by Streptococcus pneumoniae and Mycobacterium fortuitum following Ahmed glaucoma valve (AGV) surgery in a young patient. METHODS: Case report of a 13-year-old boy with purulent exudates and extensive conjunctival necrosis two months following amniotic membrane graft and conjunctival closure (for conjunctival retraction post AGV for secondary glaucoma). RESULTS: The conjunctiva showed extensive necrosis causing exposure of the tube and plate associated with frank exudates in the area adjoining the plate and anterior chamber mandating explantation of the plate along with intravitreal antibiotics. The vitreous aspirate grew Streptococcus pneumoniae while Streptococcus pneumoniae with Mycobacterium fortuitum was isolated from the explanted plate. Despite adequate control of infection following surgery, the final visual outcome was poor owing to disc pallor. CONCLUSION: Conjunctival necrosis and retraction post-AGV can cause late postoperative co-infections by fulminant and slow-growing organisms. A close follow-up is therefore essential in these cases to prevent sight-threatening complications.

Mycobacterium fortuitum infection following adalimumab treatment for psoriasis and subsequent complication-free treatment with alternate TNF-a blockers.

Tumor necrosis factor-a (TNF-a) inhibitors, such as adalimumab, are often used to treat psoriasis and psoriatic arthritis. While it is well known that these agents increase the risk of reactivation tuberculosis, recent evidence suggests that the risk of other nontuberculous mycobacterial (NTM) infections is on the rise. We report cutaneous Mycobacterium fortuitum in a 60-year-old woman with psoriasis who had been receiving adalimumab therapy for psoriatic arthritis for six months. No other risk factors were identified. M. fortuitum was cultured from a lesion on the right leg. Following resolution of the lesion, the patient has been successfully treated with infliximab infusions and subsequently certalizumab without complication for the past three years. To our knowledge, this is the first report of M. fortuitum occurring in a patient receiving adalimumab with successful subsequent treatment without complication while on another TNF-a inhibitor.

Synthesis and biological evaluation of analogues of AKT (protein kinase B) inhibitor-IV.

Inhibitors of the PI3-kinase/AKT (protein kinase B) pathway are under investigation as anticancer and antiviral agents. The benzimidazole derivative AKT inhibitor-IV (ChemBridge 5233705) affects this pathway and exhibits potent anticancer and antiviral activity. To probe its biological activity, we synthesized AKT inhibitor-IV and 21 analogues using a novel six-step route based on ZrCl(4)-catalyzed cyclization of 1,2-arylenediamines with α,ß-unsaturated aldehydes. We examined effects on viability of HeLa carcinoma cells, viability of normal human cells (NHBE), replication of recombinant parainfluenza virus 5 (PIV5) in HeLa cells, and replication of the intracellular bacterium Mycobacterium fortuitum in HeLa cells. Replacement of the benzimidazole N-ethyl substitutent of AKT inhibitor-IV with N-hexyl and N-dodecyl groups enhanced antiviral activity and cytotoxicity against the cancer cell line, but these compounds showed substantially lower toxicity (from 6-fold to >20-fold) against NHBE cells and no effect on M. fortuitum, suggesting inhibition of one or more host protein(s) required for proliferation of cancer cells and PIV5. The key structural elements identified here may facilitate identification of targets of this highly biologically active scaffold.

Components derived from Pelargonium stimulate macrophage killing of Mycobacterium species.

AIMS: To determine the capacity of extracts of Pelargonium reniforme and Pelargonium sidoides, plants of the Geraniaceae family, to stimulate the uptake and killing of mycobacteria by murine macrophages and to identify the constituents that are responsible. METHODS AND RESULTS: Bioassay-guided fractionation of aqueous P. reniforme extracts yielded five chemically distinct structures with the capacity to increase the rate of intracellular killing by macrophages. These were: gallic acid, methyl gallate, myricetin and quercitin-3-O-beta-d-glucoside, in addition to the previously unrecognized constituent 1-O-(2-(4-methoxyphenyl)ethyl-6-O-galloyl-glucopyranoside. Kinetics of intracellular accumulation of Mycobacterium tuberculosis and Mycobacterium fortuitum by macrophages were indistinguishable; pure preparations of the four previously known plant constituents stimulated macrophage killing, but not uptake, of M. tuberculosis and M. fortuitum equally well. CONCLUSIONS: A number of distinct molecular species are present in the medicinal plant P. reniforme that stimulate the killing of the intracellular pathogen M. tuberculosis. SIGNIFICANCE AND IMPACT OF THE STUDY: These observations support the view that Pelargonium extracts may have utility in the treatment of tuberculosis.

[Microbiological properties of M. porcinum isolated from a patient with impairments in IL-12/IFN-gamma pathway].

PURPOSE: Mycobacterium porcinum has been successfully isolated from the patient with abnormal signal transduction pathway of IL12/IFN-gamma. The properties of each bacterium were determined by conventional identification methods, DNA sequencing analysis and MIC assay. MATERIALS AND METHODS: M. porcinum was isolated 7 times from 1996 to 2007 from cervical lymph node, axillary lymph nodes, inguinal lymph node, brachial lymph node and site of a tumor of the patient. In another occasion, mycobacteria were isolated from lavage fluid of the endoscope in routine inspection. Using these mycobacteria, M. porcinum (ATCC33776) and M. fortuitum (ATCC6841), the conventional identification method and MIC assay were carried out. For analyses of the DNA sequencing (rpoB, dnaJ and hsp65), the ATCC type strain of mycobacteria (11 strains) which are closely related to M. porcinum were also used. RESULTS AND DISCUSSION: DNA sequencing analyses of the 7 samples isolated from the patient, were concurrently identical in 3 different genes. Drug susceptibility test showed that 7 isolates had no marked change. In conventional identification analyses, M. porcinum (ATCC33776), M. fortuitum (ATCC6841), and M. porcinum that were isolated in 1996, were able to grow at 42 degrees C. However, 6 isolates that were isolated after 1999, did not grow at 42 degrees C. The colony detectable days of these 7 strains changed from 3 to 7. Over the time, the morphology of each colony changed from smooth to rough. Though the initial isolate had the ability to utilize mannitol, the later 4 isolates had no such ability.

[Case of pneumothorax associated with pulmonary Mycobacterium fortuitum infection].

A 39-year-old man with dyspnea was revealed to have severe pneumothorax and received partial resection of the left upper lobe after unsuccessful drainage. Necrotizing epitheloid granuloma was found in the resected lung and Mycobacterium fortuitum was detected from the lesion. Chemotherapy with levofloxacin and clarithromycin was started one year after surgery because of the newly found nodular shadow near the lesion. The case experienced pyothorax due to pulmonary tuberculosis three years before and Mycobacterium avium pleuritis one year before this episode. Three-time mycobacterial pleural infection in three years seems to be uncommon. Furthermore this is the first report of pneumothorax associated with pulmonary Mycobacterium fortuitum infection.

Mycobacterium fortuitum: an iatrogenic cause of soft tissue infection in surgery.

BACKGROUND: Mycobacterium fortuitum is an uncommon cause of soft tissue infections. Treatment is often inadequate with persistence of infection unless the aetiological agent and its antibiotic sensitivity are accurately established. METHODS: Medical records of 23 patients with chronic soft tissue infection caused by M. fortuitum over a 12-year period from 1991 to 2002 were studied. RESULTS: In 20 patients the cause was iatrogenic, following intramuscular injections (12), laparoscopy (5) and other surgical procedures (3) and in three patients discharging sinuses developed spontaneously. Patients presented with recurrent abscesses or chronic discharging sinuses that did not respond to conventional surgical drainage. The diagnosis was established by isolating M. fortuitum from the tissues in all cases. The treatment consisted of a more aggressive surgical intervention in form of excision, debridement and extensive lay open with curettage and prolonged administration of appropriate antibiotics. The organism showed maximum sensitivity to amikacin and ciprofloxacin. Healing occurred in all cases. Three patients suffered recurrences: two responded to further debridement and antibiotics and are well at 2 and 5 years, respectively. CONCLUSION: A high index of suspicion based on clinical presentation is essential to diagnose M. fortuitum as a cause of soft tissue infection. Treatment involves aggressive surgical debridement and administration of combination antibiotics based on sensitivity, which should be continued for a period that will ensure complete healing and prevent recurrence.

Rapidly growing mycobacterial infections: spectrum of diseases, antimicrobial susceptibility, pathology and treatment outcomes.

OBJECTIVES: A series of cases infected with rapidly growing mycobacteria were studied to reveal the spectrum of disease, antimicrobial susceptibility, pathology, and treatment outcomes. METHOD: The cases identified as rapidly growing mycobacterial infections in Ramathibodi Hospital from January 1993 to June 1999 were retrospectively studied. RESULTS: There were 20 patients and most of the cases had no underlying disease. Only two cases were HIV-infected patients. The presenting clinical features were lymphadenitis (7), skin and subcutaneous abscess (7), eye infection (4), pulmonary infection (1), and chronic otitis media (1). Four of the seven cases with lymphadenitis had Sweet's syndrome. The organisms were Mycobacterium chelonae/abscessus group (17 cases) and Mycobacteriumfortuitum group (3 cases). The organisms were susceptible to amikacin, netilmicin and imipenem. The M. fortuitum group was susceptible to more antibiotics than the M. chelonaelabscessus group. Pathology of the infected tissue varied from non-specific findings to suppurative or caseous granuloma. The clinical responses corresponded to the antimicrobial susceptibility. Most of the patients had a good clinical outcome. A combination of two or more drugs was used for the medical treatment. Surgical resection was performed where possible to reduce the load of the organism, especially in cases with very resistant organisms. CONCLUSIONS: Rapidly growing mycobacterial infections can occur in apparently normal hosts. Clinical syndrome is variable. The pathology is non-specific and culture is needed for definite diagnosis. Clinical responses varied but seemed to correlate with the in vitro susceptibility result. More studies are needed before one can deal with these infections more effectively.

Mycobacterium fortuitum osteomyelitis in a peripheral blood stem cell transplant recipient.

Mycobacterium fortuitum is an uncommon, but well-recognized, pathogen in immunocompromised hosts, with special predilection for bone and soft tissue infections in solid organ transplant recipients. We describe a case of osteomyelitis due to this pathogen in a peripheral blood stem cell transplant recipient.