Treatment of nonpulmonary infections due to Mycobacterium fortuitum and Mycobacterium chelonei on the basis of in vitro susceptibilities

Incarcerated Ink: A Case of Mycobacterium chelonae

A 30-year-old African American male presented with pain and swelling of the right foot one month after receiving a tattoo on this foot in prison. During his admission for presumed cellulitis, he developed a rash on his contralateral (left) leg, which had been tattooed 10 months prior. A biopsy of the contralateral (left) leg showed acute, chronic, and granulomatous inflammation with a differential diagnosis including infection. His overall condition and both legs worsened, prompting biopsy and tissue culture of the right ankle and foot. Pathology of the right foot showed a granulomatous reaction. Culture grew Mycobacterium chelonae. This case highlights the importance of considering infectious etiologies for rashes appearing within tattoos and represents the importance of a full investigation to obtain the correct diagnosis.

Disseminated cutaneous Mycobacterium chelonae infection secondary to an indwelling catheter in an immunocompetent host

Background

Mycobacterium chelonae is a species of nontuberculous mycobacteria that typically causes localized cutaneous disease in immunocompetent hosts. There have been few reports of disseminated infections in immunocompetent individuals which have often been associated with invasive medical procedures.

Case Presentation

In this report, we describe a 43-year-old immunocompetent female with an implanted venous access device who presented with skin lesions increasing in size and frequency over the course of five months despite antimicrobial therapy. A diagnosis was not made until mycobacterial culture from a skin biopsy grew M. chelonae.

Conclusion

Disseminated cutaneous M. chelonae infection can be a rare complication of indwelling venous catheterization among immunocompetent patients.

A Systematic Review of Nontuberculous Mycobacterium Infection Following Anterior Cruciate Ligament Reconstruction

Although infection following anterior cruciate ligament (ACL) reconstruction is rare, these cases have potentially catastrophic ramifications. Nontuberculous mycobacteria (NTM) are ubiquitous, located in the water supply and soil. Our objective was to review the literature to characterize NTM infection following ACL reconstruction.

Methods

A database search was performed for arthroscopic ACL reconstructions that resulted in a postoperative diagnosis of NTM infection.

Results

The literature search returned 6 case reports that met the inclusion criteria. The initial postoperative presentation occurred after 3 to 52 weeks, which is consistent with reports of postoperative NTM infection.

Conclusions

The common indolent course of NTM infection hinders prompt diagnosis and treatment. Organism susceptibility testing is crucial for effective treatment and limiting unnecessary antibiotic exposure.

Clinical Relevance

The duration of medical treatment for NTM infection is 4 to 6 months, depending on the severity of disease and species. Based on the aggregate literature, we recommend removal of local implants if the infection is localized and without articular involvement. However, in cases of articular involvement, all fixation and graft material should be removed.

Peritoneal dialysis-related peritonitis with encapsulated ascites due to Mycobacterium abscessus subsp. massilience and subsp. bolletii: a case series and literature review

Background

As there is no established standard of care for non-tuberculous mycobacterium (NTM) peritoneal dialysis (PD)-related peritonitis, its treatments have to be case-dependent, which is often difficult. Additionally, several reported cases were accompanied by encapsulated ascites, adhesive ileus, and encapsulating peritoneal sclerosis, suggesting treatment difficulties. We report two cases of PD-related peritonitis with encapsulated ascites due to Mycobacterium abscessus subsp. massilience and subsp. bolletii. To the best of our knowledge, this is the first case series to report PD-related peritonitis caused by Mycobacterium abscessus subsp. bolletii.

Case presentation

The first case is that of a 74-year-old male patient who started PD six years ago for end-stage renal failure due to diabetic nephropathy. In February 2021, he presented with signs of infection at the exit-site and swelling of the tunnel. Mycobacterium abscessus subsp. massilience was detected in the culture of the exit-site exudate; thus, he was diagnosed with tunnel infection (caused by NTM). Subsequently, fever, abdominal pain, and increased cell counts in the PD drainage fluid were observed, and he was judged to have NTM peritonitis. His general condition improved after PD catheter removal in addition to antimicrobial treatment and encapsulated ascites drainage. The second case is that of a 52-year-old man who commenced PD for end-stage renal failure due to nephrosclerosis 12 years ago. In May 2022, he was diagnosed with PD-related peritonitis based on signs of infection at the exit-site, encapsulated ascites on computed tomography, and a cloudy PD drainage fluid. Mycobacterium abscessus subsp. bolletii was detected in the culture of the exit-site exudate, which led to the diagnosis of NTM peritonitis. In addition to antimicrobial treatment, PD catheter removal and encapsulated ascites drainage were performed. The patient also had adhesive bowel obstruction due to peritonitis and required decompression therapy with the insertion of a gastric tube.

Conclusions

PD catheter removal and encapsulated ascites drainage might have improved inflammation and treatment outcomes. Additionally, Mycobacterium abscessus might be prone to forming encapsulated cavities and/or intestinal adhesions; however, further accumulation of cases clarifying “subspecies” of Mycobacterium abscessus is necessary to confirm this hypothesis.

Vertebral osteomyelitis caused by Mycobacteroides abscessus subsp. abscessus resulting in spinal cord injury due to vertebral body fractures

Nontuberculous mycobacteria (NTM) rarely cause vertebral osteomyelitis; however, the clinical characteristics of vertebral osteomyelitis caused by NTM are poorly understood due to its rarity. A 74-year-old man with lung cancer was treated with prednisolone for immune checkpoint inhibitor-associated immune-related adverse events. He had been experiencing mild back pain without febrile episodes for five months, and was admitted to the hospital for worsening back pain and progressive paraplegia. Magnetic resonance imaging showed spinal cord compression at T4-5 due to fractures of the T5 and T7 vertebral bodies. The culture of a sample of pus from the T7 vertebral body obtained at the time of spinal fusion surgery yielded the Mycobacteroides abscessus (M. abscessus) complex. The patient was diagnosed with vertebral osteomyelitis caused by M. abscessus complex and treated with clarithromycin, amikacin, and imipenem; clarithromycin was later replaced by sitafloxacin because of inducible macrolide resistance. However, his neurologic deficits were irreversible, and he died due to a deteriorating general condition. The strain was identified up to subspecies level as M. abscessus subsp. abscessus by hsp65 and rpoB sequencing and nucleic acid chromatography. Although vertebral osteomyelitis due to NTM is rare, delayed diagnosis can lead to serious complications or poor outcomes. A prolonged clinical course, less frequent fever, vertebral destruction or spinal deformity, neurological deficits, or immunosuppressed conditions might be suggestive of NTM vertebral osteomyelitis.

β-Lactam Combinations That Exhibit Synergy against Mycobacteroides abscessus Clinical Isolates

Mycobacteroides abscessus (Mab) is an opportunistic environmental pathogen that can cause chronic pulmonary disease in the setting of structural lung conditions such as bronchiectasis, chronic obstructive pulmonary disease, and cystic fibrosis. These infections are often incurable and associated with rapid lung function decline. Mab is naturally resistant to most of the antibiotics available today, and current treatment guidelines require at least 1 year of daily multidrug therapy, which is often ineffective and is associated with significant toxicities. β-Lactams are the most widely used class of antibiotics and have a demonstrated record of safety and tolerability. Here, using a panel of recent clinical isolates of Mab, we evaluated the in vitro activities of dual-β-lactam combinations to identify new treatments with the potential to treat infections arising from a wide range of Mab strains. The Mab clinical isolates were heterogeneous, as reflected by the diversity of their genomes and differences in their susceptibilities to various drugs. Cefoxitin and imipenem are currently the only two β-lactams included in the guidelines for treating Mab disease, yet they are not used concurrently in clinical practice. However, this dual-β-lactam combination exhibited synergy against 100% of the isolates examined (n = 21). Equally surprising is the finding that the combination of two carbapenems, doripenem and imipenem, exhibited synergy against the majority of Mab isolates. In the setting of multidrug-resistant Mab disease with few therapeutic options, these combinations may offer viable immediate treatment options with efficacy against the broad spectrum of Mab strains infecting patients today.

Mycobacterium abscessus felon complicated with osteomyelitis: not an ordinary nail salon visit

Mycobacterium abscessus is an environmental organism that has been implicated in pulmonary and extrapulmonary infections. Cases of furunculosis have been described in patients who underwent footbaths in nail salons; however, no cases of severe soft tissue infections or osteomyelitis have been reported following manicures. Here, we present the case of a 50-year-old woman who developed a felon in right index finger one week after having a manicure. She underwent incision and drainage of affected area. Cultures from purulence grew Mycobacterium abscessus. Imaging revealed osteomyelitis of distal phalanx. She was successfully treated with a prolonged course of antibiotics that included imipenem, linezolid, tigecycline, and clarithromycin. We highlight the importance of recognizing this uncommon complication and advocate the use of combined antibiotic regimens for an adequate treatment of this infection.

Mycobacterium chelonae bacteraemia in a patient with myasthenia gravis receiving long-term steroid therapy

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms found in soil and water. Infections caused by NTM are increasing with conditions ranging from harmless colonization to invasive infections, the latter being more common in immunocompromised hosts. In this report, we present a case of bacteraemia caused by Mycobacterium chelonae, a rapidly growing NTM belonging to Class IV in the Runyon classification, in a 71-year-old male with ocular myasthenia gravis undergoing treatment with oral prednisolone. Gram staining of these organisms from blood culture can be easily overlooked or confused with diptheroids. Detection of Gram-positive bacilli should prompt Ziehl–Neelsen staining to distinguish diphtheroids from rapidly growing mycobacteria in immunosuppressed patients. In addition, speciation and antimicrobial susceptibility testing are of paramount importance in such cases as there is considerable variation in the resistance patterns between different species of NTM. Line probe assay provides a rapid and reliable method for identification of NTM to the species level, which can guide treatment with appropriate antibiotics. This case report highlights the importance of early detection of such cases so as to optimize management and improve patient outcomes.

Epidemiology, diagnosis & treatment of non-tuberculous mycobacterial diseases

Non-tuberculous mycobacteria (NTM) are ubiquitously present in the environment, but NTM diseases occur infrequently. NTM are generally considered to be less virulent than Mycobacterium tuberculosis, however, these organisms can cause diseases in both immunocompromised and immunocompetent hosts. As compared to tuberculosis, person-to-person transmission does not occur except with M. abscessus NTM species among cystic fibrosis patients. Lung is the most commonly involved organ, and the NTM-pulmonary disease (NTM-PD) occurs frequently in patients with pre-existing lung disease. NTM may also present as localized disease involving extrapulmonary sites such as lymph nodes, skin and soft tissues and rarely bones. Disseminated NTM disease is rare and occurs in individuals with congenital or acquired immune defects such as HIV/AIDS. Rapid molecular tests are now available for confirmation of NTM diagnosis at species and subspecies level. Drug susceptibility testing (DST) is not routinely done except in non-responsive disease due to slowly growing mycobacteria ( M. avium complex, M. kansasii) or infection due to rapidly growing mycobacteria, especially M. abscessus. While the decision to treat the patients with NTM-PD is made carefully, the treatment is given for 12 months after sputum culture conversion. Additional measures include pulmonary rehabilitation and correction of malnutrition. Treatment response in NTM-PD is variable and depends on isolated NTM species and severity of the underlying PD. Surgery is reserved for patients with localized disease with good pulmonary functions. Future research should focus on the development and validation of non-culture-based rapid diagnostic tests for early diagnosis and discovery of newer drugs with greater efficacy and lesser toxicity than the available ones.

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.

Cutaneous nontuberculous mycobacterial infection in Thailand: A 7-year retrospective review

A remarkable increase in the prevalence of cutaneous nontuberculous mycobacterial (NTM) infection has occurred worldwide. However, updated data regarding cutaneous NTM infection in Thailand is limited.This study aim to describe the clinical manifestations, pathogenic organism, and prognostic factors of cutaneous NTM infections among patients living in Thailand.The electronic medical records of all patients with confirmatory diagnosis of cutaneous NTM infection from either positive cultures or polymerase chain reaction were retrospectively reviewed at a university-based hospital.From 2011 to 2017, a total of 88 patients with a confirmed diagnosis of cutaneous NTM infection were included. Mycobacterium abscessus was the most common pathogens followed by M haemophilum and M marinum (61.4%, 10.2%, and 8.1%, respectively). Nodule and plaque were 2 most common lesions (26.4% and 25.5%, respectively) and lower leg is the most common site of involvement (50.9%). The majority of patients presented with single lesion (67%). Seven patients (7.9%) had history of surgical procedure and/or cosmetic injection before the development of lesion and all pathogenic organisms in this group were rapidly growing mycobacteria. Sweet's syndrome and erythema nodosum were the 2 most common reactive dermatoses, presented in 3.4% and 2.3%, respectively. The majority of patients infected with cutaneous M haemophilum infections were immunocompromised and lacked history of preceding trauma (77.8%). Patients with cutaneous NTM that receiving less than 3 medications was associated with higher disease relapse (odds ratio 65.86; P = .02).M abscessus is the most common pathogen of cutaneous NTM infection in Thailand. The prevalence of M haemophilum is increasing and should be particularly cautious in immunocompromised patients. Rapidly growing mycobacteria should be suspected in all cases of procedure-related cutaneous NTM. We recommend at least 3 antibiotics should be considered for cutaneous NTM infection to reduce the rate of relapse.

Mycobacterium fortuitum ventriculoperitoneal shunt infection in an immunocompromised patient: A case report

We present a case of Mycobacterium fortuitum ventriculoperitoneal shunt infection in a 26-year-old immunocompromised woman. The patient was treated with revision and replacement of her peritoneal shunt and prolonged combination antimicrobial therapy. There are no established guidelines for the treatment of VP shunt infections due to M. fortuitum. We review the literature and provide treatment recommendations.

Diagnosis and management of postlaparotomy wound infection caused by Mycobacterium fortuitum

Mycobacterium fortuitum is ubiquitous in nature and can cause a wide variety of lesions in humans with immunocompromised or antecedent chronic illness. Clinical diagnosis is difficult and relapses are seen. This is due to the fact that they are not critically investigated and are not responded to traditional antitubercular treatment and other antibiotics. Herewith, we report a case of M. fortuitum causing laparotomy port infection-causing repeated multiple abscess on the anterior abdominal wall and treated with amikacin and clarithromycin. The wound healed completely and the patient recovered after administering a combination of amikacin and clarithromycin. We conclude that strict standard operating procedures should be followed to prevent mycobacteria other than tuberculosis (MOTT) infections during and after surgical procedures. Any postoperative, chronic infection which is not responding to conventional antibiotics should be highly suspected for such MOTT infections. Antibiotic susceptibility testing should be performed so as to identify the required antibiotic combination and treated accordingly to prevent further complications and to reduce the cost of treatment.

Cardiovascular implantable electronic device infection with rapidly growing mycobacteria

Cardiovascular implantable electronic devices, which are frequently utilized for many cardiovascular diseases, can become infected, leading to significant morbidity and mortality. This case highlights an unusual presentation of pacemaker generator pocket infection with Mycobacterium fortuitum.

Synergistic Efficacy of β-Lactam Combinations against Mycobacterium abscessus Pulmonary Infection in Mice

Mycobacterium abscessus is an emerging pathogen capable of causing invasive pulmonary infections in patients with chronic lung diseases. These infections are difficult to treat, necessitating prolonged multidrug therapy, which is further complicated by extensive intrinsic and acquired resistance exhibited by clinical M. abscessus isolates. Therefore, development of novel treatment regimens effective against drug-resistant strains is crucial. Prior studies have demonstrated synergistic efficacy of several β-lactams against M. abscessus in vitro; however, these combinations have never been tested in an animal model of M. abscessus pulmonary disease. We utilized a recently developed murine system of sustained M. abscessus lung infection delivered via an aerosol route to test the bactericidal efficacy of four novel dual β-lactam combinations and one β-lactam/β-lactamase inhibitor combination. All five of the novel combinations exhibited synergy and resulted in at least 6-log₁₀ reductions in bacterial burden in the lungs of mice at 4 weeks compared to untreated controls (P = 0.038).

Surgical wound infection following open humeral fracture caused by Mycobacterium houstonense: a case report

Background

Historically Mycobacterium houstonense belongs to the unnamed third biovariant complex of the Mycobacterium fortuitum group, which are sorbitol positive. To date, there have been few reports of human infection induced by M. houstonense worldwide.

Case presentation

We describe the case of a 68-year-old man with surgical wound infection, following an open humeral fracture, caused by M. houstonense and Escherichia coli. An implant bone plate had been embedded for internal fixation during surgery on the humeral fracture previously. A week later E. coli was isolated from the skin wound secretions. Cefoperazone-sulbactam was used for treatment for two weeks but the infection was not controlled, with a subsequent risk of deep wound infection. External fixation of the fracture was then performed instead of internal fixation. Ten days later, M. houstonense was isolated from new wound secretions. M. houstonense was identified by the molecular sequencing method. The TREK Diagnostic System was used to test the susceptibility to antibiotics by the microbroth dilution method. Levofloxacin and amikacin were used for treatment according to the results of the susceptibility test and the patient’s condition obviously improved.

Conclusion

To the best of our knowledge, this is the first case in China of human surgical wound infection caused by M. houstonense following open humeral fracture. The combination of levofloxacin and amikacin was effective in the treatment of M. houstonense infection.

Mycobacterium fortuitum Meningitis: Approach to Lumboperitoneal Shunt Infection

Mycobacterium fortuitum is a rare, opportunistic pathogen most frequently contracted through contact with a contaminated source. An immunocompetent 26-year-old female patient presented to our institution with an infected lumboperitoneal (LP) shunt presenting as continued nonhealing wounds. After multiple debridements, shunt revisions, and wound closure failures, infectious disease specialists were consulted. The wound cultures returned positive for M. fortuitum and the shunt was removed. Cerebrospinal fluid studies revealed significant pleocytosis with normal opening pressure, and the patient was diagnosed as having secondary meningitis. After shunt removal, the patient was treated with intravenous and oral antibiotics, resulting in infection resolution. Five months later, a new LP shunt was placed without infection recurrence. Although M. fortuitum was previously reported in neurosurgical patients with ventriculoperitoneal shunts, which are summarized here, to date this is the first case in the literature of M. fortuitum meningitis from an LP shunt. This case demonstrates the importance of clinicians considering uncommon and slow-growing pathogens, as well as consulting infectious disease specialists for patients with persistent, unexplained infections.

Select β-Lactam Combinations Exhibit Synergy against Mycobacterium abscessus In Vitro

Mycobacterium abscessus is a nontuberculous mycobacterium that causes invasive pulmonary infections in patients with structural lung disease. M. abscessus is intrinsically resistant to several classes of antibiotics, and an increasing number of strains isolated from patients exhibit resistance to most antibiotics considered for treatment of infections by this mycobacterium. Therefore, there is an unmet need for new regimens with improved efficacy to treat this disease. Synthesis of the essential cell wall peptidoglycan in M. abscessus is achieved via two enzyme classes, l,d- and d,d-transpeptidases, with each class preferentially inhibited by different subclasses of β-lactam antibiotics. We hypothesized that a combination of two β-lactams that comprehensively inhibit the two enzyme classes will exhibit synergy in killing M. abscessus Paired combinations of antibiotics tested for in vitro synergy against M. abscessus included dual β-lactams, a β-lactam and a β-lactamase inhibitor, and a β-lactam and a rifamycin. Of the initial 206 combinations screened, 24 pairs exhibited synergy. A total of 13/24 pairs were combinations of two β-lactams, and 12/24 pairs brought the MICs of both drugs to within the therapeutic range. Additionally, synergistic drug pairs significantly reduced the frequency of selection of spontaneous resistant mutants. These novel combinations of currently available antibiotics may offer viable immediate treatment options against highly-resistant M. abscessus infections.

Peritoneal dialysis-associated infection caused by Mycobacterium abscessus: a case report

Background

Peritoneal dialysis (PD)-associated infection caused by Mycobacterium spp. is rare. Mycobacterium abscessus is one of the most resistant acid-fast bacteria, and treatment is also the most difficult and refractory. Thus, we report a case of PD-associated peritonitis caused by Mycobacterium abscessus that was difficult to treat and led to PD failure.

Case presentation

We recently encountered a 56-year-old man who developed PD-associated infection. We initially suspected exit-site infection (ESI) and tunnel infection (TI) caused by methicillin-resistant coagulase-negative Staphylococcus. However, antibiotic therapy did not provide any significant improvement. Thus, we performed simultaneous removal and reinsertion of a PD catheter at a new exit site. The patient subsequently developed peritonitis and Mycobacterium abscessus was detected in the peritoneal effluent. Thus, the reinserted catheter was removed, hemodialysis was started, and the patient was eventually discharged.

Conclusions

In cases of refractory ESI or TI, it is important to consider non-tuberculous mycobacteria as the potentially causative organism. Even if acid-fast bacterial staining is negative or not performed, detection of Gram-negative bacillus may lead to suspicion and early identification of Mycobacterium spp. In PD-associated infection by Mycobacterium abscessus, catheter removal is necessary in many cases. Simultaneous removal and reinsertion of the catheter is not recommended, even in cases of ESI or TI. Reinsertion should only be attempted after complete resolution of peritoneal symptoms. After removal of the catheter, careful follow-up is necessary, paying attention to complications such as wound infection, peritonitis, and ileus. In addition, the selection and treatment period of antibiotics in PD-associated infection by Mycobacterium abscessus remains unclear, and it is an important topic for future discussion.

Mycobacterium abscessus and β-Lactams: Emerging Insights and Potential Opportunities

β-lactams, the most widely used class of antibiotics, are well-tolerated, and their molecular mechanisms of action against many bacteria are well-documented. Mycobacterium abscessus (Mab) is a highly drug-resistant rapidly-growing nontuberculous mycobacteria (NTM). Only in recent years have we started to gain insight into the unique relationship between β-lactams and their targets in Mab. In this mini-review, we summarize recent findings that have begun to unravel the molecular basis for overall efficacy of β-lactams against Mab and discuss emerging evidence that indicates that we have yet to harness the full potential of this antibiotic class to treat Mab infections.

Mycobacterium abscessus Infections in Children: A Review of Current Literature

There is limited literature on Mycobacterium abscessus infections in children and limited data about its diagnosis and management. The incidence of infections due to M abscessus appears to be increasing in certain populations and can be a significant cause of morbidity and mortality.Management of these infections is challenging and relies on combination antimicrobial therapy and debridement of diseased tissue, depending on the site and extent of disease. Treatment regimens often are difficult to tolerate, and the antimicrobials used can cause significant adverse effects, particularly given the long duration of therapy needed.This review summarizes the literature and includes information from our own institution's experience on pediatric M abscessus infections including the epidemiology, transmission, clinical manifestations, and the management of these infections. Adult data have been used where there are limited pediatric data. Further studies regarding epidemiology and risk factors, clinical presentation, optimal treatment, and outcomes in children are necessary.

Multi-drug resistant Mycobacterium chelonae scleral buckle infection

Purpose

To describe a case of Multi-drug resistant Mycobacterium chelonae scleral buckle infection.

Observations

A 56 year-old male with history of retinal detachment repair with scleral buckle 20 years prior presented with 8 months of intermittent pain and redness in the left eye. The patient was diagnosed with scleral buckle infection, the buckle was removed, and cultures revealed multi-drug resistant Mycobacterium chelonae. The postoperative course included orbital cellulitis treated with systemic linezolid, clarithromycin, and imipenem. All systemic antibiotics were discontinued on post-operative day 25, visual acuity improved to 20/25, the retina remained attached, and no recurrence occurred over 3 years of follow-up.

Conclusions and importance

NTM infections are typically chronic and often require lengthy treatment. SB infection is rare, but often associated with biofilm and antibiotic resistance. In spite of removing the SB, anchoring sutures, sheath surrounding the buckle and associated biofilm, a prolonged course of systemic antibiotics may be necessary in some patients.

Evaluation of greater wax moth larvae, Galleria mellonella, as a novel in vivo model for non-tuberculosis Mycobacteria infections and antibiotic treatments

PURPOSE

To evaluate the suitability of Galleria mellonella larvae as an in vivo model and drug-screening tool for mycobacteria infections.

METHODOLOGY

Larvae were infected using a range of inoculum sizes from a variety of rapid-growing mycobacteria, including strains of M. fortuitum, M. marinum and M. aurum. Larval survival, internal bacterial burden and the effects of amikacin, ciprofloxacin, ethambutol, isoniazid and rifampicin treatment on larval survival were measured over 144 h. The effects of these anti-mycobacterial drugs on phagocytosis and circulating haemocyte numbers were also examined using microscopy.

RESULTS

Larval survival decreased after infection with M. fortuitum and M. marinum in a dose-dependent manner, but remained unaffected by M. aurum. Heat-killed bacteria did not cause larval death. Where antibiotic monotherapy was efficacious, larval survival post-infection increased in a dose-dependent fashion. However, efficacy varied between different antibiotics and species of infecting mycobacteria and, apart from rifampicin, efficacy in vivo correlated poorly with the in vitro minimum inhibitory concentrations (MICs). Combinations of antibiotics led to higher survival of infected larvae than antibiotic monotherapy. Selected antibiotic treatments that enhanced larval survival reduced the overall internal burden of infecting mycobacteria, but did not eradicate the pathogens. Administration of amikacin or ethambutol to uninfected larvae induced an initial transient increase in the numbers of circulating haemocytes and reduced the phagocytic rate of haemocytes in larvae infected with M. marinum.

CONCLUSIONS

This report demonstrates the potential of employing a wax moth larvae model for studying fast-growing mycobacteria infections, and as a cheap, effective system for initial screening of novel treatments.

Activities of Dual Combinations of Antibiotics Against Multidrug-Resistant Nontuberculous Mycobacteria Recovered from Patients with Cystic Fibrosis

Patients with cystic fibrosis (CF) are at risk for recurrent pulmonary infections due to increased viscosity of airway secretions, leading to persistent colonization with pathogenic bacteria, including nontuberculous mycobacteria (NTM). Extensive antibiotic use for treatment of infections has led to increasing antimicrobial resistance, which is a significant barrier to the treatment of NTMs. We examined the in vitro activity of several antibiotics against a selection of the most drug-resistant clinical isolates of Mycobacterium abscessus, Mycobacterium chelonae, and Mycobacterium avium complex recovered from CF patients at our institution, as well as paired combinations of antibiotics against a subset of M. abscessus strains, to determine whether they exhibit synergy in inhibiting bacterial growth. Most isolates displayed resistance to at least six of the nine antibiotics tested for which phenotypic interpretation is available, and elevated minimum inhibitory concentrations (MICs) were observed for many of the other drugs. The major exception was clofazimine, which had relatively low MICs for most isolates across all species. When synergy testing was performed by using paired combinations of drugs, clofazamine and clarithromycin exhibited 100% synergy for all combinations tested, as did amikacin, with the exception of one isolate. These results suggest that synergistic antibiotic combinations are capable of overcoming drug resistance in vitro, and laboratories might consider implementation of synergy testing in multidrug-resistant (MDR)-NTM organisms to guide treatment decisions in the setting of extensive antimicrobial resistance.

Non-Tuberculous Mycobacteria Infection Following Autologous Fat Grafting on the Face

LEVEL OF EVIDENCE

5.

US Cystic Fibrosis Foundation and European Cystic Fibrosis Society consensus recommendations for the management of non-tuberculous mycobacteria in individuals with cystic fibrosis

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms that can cause chronic pulmonary infection, particularly in individuals with pre-existing inflammatory lung disease such as cystic fibrosis (CF). Pulmonary disease caused by NTM has emerged as a major threat to the health of individuals with CF but remains difficult to diagnose and problematic to treat. In response to this challenge, the US Cystic Fibrosis Foundation (CFF) and the European Cystic Fibrosis Society (ECFS) convened an expert panel of specialists to develop consensus recommendations for the screening, investigation, diagnosis and management of NTM pulmonary disease in individuals with CF. Nineteen experts were invited to participate in the recommendation development process. Population, Intervention, Comparison, Outcome (PICO) methodology and systematic literature reviews were employed to inform draft recommendations. An anonymous voting process was used by the committee to reach consensus. All committee members were asked to rate each statement on a scale of: 0, completely disagree, to 9, completely agree; with 80% or more of scores between 7 and 9 being considered ‘good’ agreement. Additionally, the committee solicited feedback from the CF communities in the USA and Europe and considered the feedback in the development of the final recommendation statements. Three rounds of voting were conducted to achieve 80% consensus for each recommendation statement. Through this process, we have generated a series of pragmatic, evidence-based recommendations for the screening, investigation, diagnosis and treatment of NTM infection in individuals with CF as an initial step in optimising management for this challenging condition.

Pacemaker pocket infection due to environmental mycobacteria: Successful management of an outbreak and steps for prevention in future

Background

An outbreak of surgical site infection (SSI) due to environmental mycobacteria (EMB) occurred in a hospital in Eastern India.

Method

A quality improvement project (QIP) was undertaken to analyze the causes and prevent further outbreak. Step (1) Proof of the need: Four patients who had undergone pacemaker implantation consecutively during a 10-day period developed SSI. Step (2) Diagnostic journey: Since all patients developed SSI within 2 months of implantation, a common source of infection was likely. Atypical mycobacteria (AMB) were grown from surgical sites as well as from the surface of operation table, image intensifier, and lead aprons. It was a rapid growing variety that lacked pigment, a characteristic of EMB with pathogenic potential. The EMB was finally traced to its source, the overhead water tank. Step (3) Remedial journey: By thorough cleaning of the water tank and enriching its chlorine content, the EMB was eliminated from its source. Step (4) Holding the gains: Protocol for cleaning the water tank once in 3 months was made. A checklist was prepared to ensure compliance to asepsis protocol in the operation theater. In the ensuing 5 years, the infection did not recur.

Result

The bacteria that caused SSI were identified as EMB that grew in the water tank and contaminated the operation room. It could be eliminated by appropriate measures.

Interpretation

Water is a potential reservoir for EMB. Use of the term ‘environmental mycobacteria’ instead of ‘atypical mycobacteria’ will generate awareness about contamination as the cause of SSI.

Non-Tuberculous Mycobacteria: Classification, Diagnostics, and Therapy

Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 140 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent (65-90 %). There is growing evidence that the incidence of NTM lung diseases and associated hospitalizations are on the rise, mainly in regions with a low prevalence of tuberculosis. A crucial clinical problem remains the evaluation of NTM significance in relation to the disease, especially in regard to the colonization of the respiratory tract in patients with residual lesions after tuberculosis or bronchiectasis. Clinical and radiographic pictures of mycobacteriosis, as well as therapy, have often similarities to those of tuberculosis. The treatment regimen should be individualized. In addition to antituberculotics, antibiotics are used more frequently. The most common mycobacteria causing lung disease in Slovakia are Mycobacterium avium and Mycobacterium abscessus.

Drug susceptibility testing of nontuberculous mycobacteria

Diseases caused by nontuberculous mycobacteria are emerging in many settings. With an increased number of patients needing treatment, the role of drug susceptibility testing is again in the spotlight. This articles covers the history and methodology of drug susceptibility tests for nontuberculous mycobacteria, but focuses on the correlations between in vitro drug susceptibility, pharmacokinetics and in vivo outcomes of treatment. Among slow-growing nontuberculous mycobacteria, clear correlations have been established for macrolides and amikacin (Mycobacterium avium complex) and for rifampicin (Mycobacterium kansasii). Among rapid-growing mycobacteria, correlations have been established in extrapulmonary disease for aminoglycosides, cefoxitin and co-trimoxazole. In pulmonary disease, correlations are less clear and outcomes of treatment are generally poor, especially for Mycobacterium abscessus. The clinical significance of inducible resistance to macrolides among rapid growers is an important topic. The true role of drug susceptibility testing for nontuberculous mycobacteria still needs to be addressed, preferably within clinical trials.

Mycobacterium fortuitum thoracic empyema: A case report and review of the literature

Mycobacterium fortuitum is a rapidly growing nontuberculous mycobacterium. This microorganism is an uncommon etiological agent of lung lesions; among lung lesions caused by M. fortuitum, thoracic empyema is particularly rare. A 61-year-old man who had been treated for chronic hypercapnic respiratory failure with noninvasive ventilation was admitted because of breathing difficulty and was found to have M. fortuitum thoracic empyema. He improved after the administration of amikacin, imipenem/cilastatin, and clarithromycin following sulfamethoxazole/trimethoprim and clarithromycin. This is the first report of M. fortuitum thoracic empyema in a patient without human immunodeficiency virus infection. The thoracic empyema may have developed via a pulmonary fistula in this case. This case highlights the fact that we must be aware of the possibility of M. fortuitum thoracic empyema, especially in patients with M. fortuitum lung infection and treatment with noninvasive ventilation. Multidrug therapy may be effective and important to the resolution of M. fortuitum thoracic empyema.

Nontuberculous Mycobacterial Ocular Infections: A Systematic Review of the Literature

Nontuberculous or atypical mycobacterial ocular infections have been increasing in prevalence over the past few decades. They are known to cause periocular, adnexal, ocular surface and intraocular infections and are often recalcitrant to medical therapy. These infections can potentially cause detrimental outcomes, in part due to a delay in diagnosis. We review 174 case reports and series on nontuberculous mycobacterial (NTM) ocular infections and discuss etiology, microbiology, risk factors, diagnosis, clinical presentation, and treatment of these infections. History of interventions, trauma, foreign bodies, implants, contact lenses, and steroids are linked to NTM ocular infections. Steroid use may prolong the duration of the infection and cause poorer visual outcomes. Early diagnosis and initiation of treatment with multiple antibiotics are necessary to achieve the best visual outcome.

Nontuberculous mycobacterial osteomyelitis

Osteomyelitis caused by nontuberculous mycobacteria (NTM) can have severe consequences and a poor prognosis. Physicians therefore need to be alert to this condition, especially in immunocompromised patients. Although the pathogenesis of NTM osteomyelitis is still unclear, studies in immunodeficient individuals have revealed close relationships between NTM osteomyelitis and defects associated with the interleukin-12-interferon-γ-tumor necrosis factor-α axis, as well as human immunodeficiency virus infection, various immunosuppressive conditions, and diabetes mellitus. Culture and species identification from tissue biopsies or surgical debridement tissue play crucial roles in diagnosing NTM osteomyelitis. Suitable imaging examinations are also important. Adequate surgical debridement and the choice of appropriate, combined antibiotics for long-term anti-mycobacterial chemotherapy, based on in vitro drug susceptibility tests, are the main therapies for these bone infections. Bacillus Calmette-Guerin vaccination might have limited prophylactic value. The use of multiple drugs and long duration of treatment mean that the therapeutic process needs to be monitored closely to detect potential side effects. Adequate duration of anti-mycobacterial chemotherapy together with regular monitoring with blood and imaging tests are key factors determining the recovery outcome in patients with NTM osteomyelitis.

Surgical site infections due to rapidly growing mycobacteria in puducherry, India

BACKGROUND

Rapidly growing Mycobacteria are increasingly recognized, nowadays as an important pathogen that can cause wide range of clinical syndromes in humans. We herein describe unrelated cases of surgical site infection caused by Rapidly growing Mycobacteria (RGM), seen during a period of 12 months.

MATERIALS AND METHODS

Nineteen patients underwent operations by different surgical teams located in diverse sections of Tamil Nadu, Pondicherry, Karnataka, India. All patients presented with painful, draining subcutaneous nodules at the infection sites. Purulent material specimens were sent to the microbiology laboratory. Gram stain and Ziehl-Neelsen staining methods were used for direct examination. Culture media included blood agar, chocolate agar, MacConkey agar, Sabourauds agar and Lowenstein-Jensen medium for Mycobacteria. Isolated microorganisms were identified and further tested for antimicrobial susceptibility by standard microbiologic procedures.

RESULTS

Mycobacterium fortuitum and M.chelonae were isolated from the purulent drainage obtained from wounds by routine microbiological techniques from all the specimens. All isolates analyzed for antimicrobial susceptibility pattern were sensitive to clarithromycin, linezolid and amikacin but were variable to ciprofloxacin, rifampicin and tobramycin.

CONCLUSION

Our case series highlights that a high level of clinical suspicion should be maintained for patients presenting with protracted soft tissue lesions with a history of trauma or surgery as these infections not only cause physical but also emotional distress that affects both the patients and the surgeon.

Mycobacterium fortuitum skin infections after subcutaneous injections with Vietnamese traditional medicine: a case report

Background

Iatrogenic skin and soft tissue infections by rapidly growing mycobacteria are described with increasing frequency, especially among immunocompromised patients.

Case presentation

Here, we present an immunocompetent patient with extensive Mycobacterium fortuitum skin and soft tissue infections after subcutaneous injections to relieve joint pains by a Vietnamese traditional medicine practitioner. Moreover, we present dilemmas faced in less resourceful settings, influencing patient management.

Conclusion

This case illustrates the pathogenic potential of rapid growing mycobacteria in medical or non-medical skin penetrating procedures, their world-wide distribution and demonstrates the dilemmas faced in settings with fewer resources.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0550-z) contains supplementary material, which is available to authorized users.

Postsurgical wound infections due to rapidly growing mycobacteria in Swiss medical tourists following cosmetic surgery in Latin America between 2012 and 2014

Between October 2012 and August 2014, several Swiss patients developed severe soft tissue infections due to rapidly growing mycobacteria following cosmetic surgery in the Dominican Republic, Ecuador and Mexico. Infections were caused by Mycobacterium abscessus (n=5), Mycobacterium sp. JAN1 (n=1) and M. conceptionense (n=1). Similar cases may have remained unrecognised due to a lack of notification requirements. Microbiological work-up of medical tourists with infections following cosmetic surgery should include rapidly growing mycobacteria.

Cutaneous Mycobacterium fortuitum Infection: Successfully Treated with Amikacin and Ofloxacin Combination

Cutaneous infections caused by atypical mycobacteria are uncommon and the diagnosis can be missed unless there is strong clinical suspicion supported by laboratory confirmation. We report a case of chronic discharging sinus caused by Mycobacterium fortuitum in a young healthy immunocompetent individual. The patient recovered completely following amikacin and ofloxacin therapy.

Misidentification of Mycobacterium fortuitum in an immunocompetent patient presenting with a unilateral neck mass

A 31-year-old African man with a blameless medical history presented with an enlarging neck swelling of 6 months duration. He was systemically well with normal heamatobiochemistry. MRI of the neck demonstrated abnormal signalling in the subcutaneous fat overlying the posterior spinal muscles in the midline and the left sternocleidomastoid muscle. Scanty growth of Rhodococcus equi was reported from a turbid fine needle aspirate of the neck on two separate occasions. The swelling progressed despite numerous antibiotic combinations which necessitated surgical debridement. Analysis of debrided tissue using 16S rDNA surprisingly identified Mycobacterium fortuitum, not R equi, thereby resolving our diagnostic conundrum.