Skin and Soft Tissue Infections Caused by Mycobacterium chelonae: More Common Than Expected?

Mycobacterium chelonae is a rapidly growing non-tuberculous mycobacterium, which causes infections of the human skin and soft tissue. Despite an increasing incidence of such infections, patients are often misdiagnosed. We report here 5 patients with cutaneous and/or soft tissue infection due to M. chelonae who were diagnosed and treated at our centre. Two of the 5 patients were on immunosuppressive treatment. While clinical presentations differed in each patient, all had a long history of skin lesions. In addition to careful history-taking, tissue biopsies were obtained for mycobacterial culture and histopathological examination. Culture-directed antibiotic therapy was initiated, which resulted in a slow, but continuous, healing of the lesions. In summary, M. chelonae infections are still relatively rare, but should be considered in both immunocompromised and immunocompetent patients with prolonged skin lesions resistant to standard antibiotic treatment. For diagnosis, tissue analysis for mycobacterial culture and histopathological examination, and once diagnosed, adequate antibiotic treatment, is needed.

Mycobacterium abscessus infections in lung transplant recipients: 15-year experience from a single institution.

PURPOSE: To evaluate our institutional experience with Mycobacterium abscessus infections occurring in lung transplant recipients (LTR). METHODS: We retrospectively reviewed our prospectively collected institutional adult lung transplant database from 2001 to 2015 to identify patients with M. abscessus or Mycobacterium chelonae/abscessus infection before or after transplantation. Untreated, colonized patients were excluded from the study. Electronic health records of nine out of 516 lung recipients (1.74%) with clinical infection were reviewed to determine outcomes. RESULTS: Seven patients acquired the infection after transplantation. Indications for transplantation were: idiopathic pulmonary fibrosis (in 6), chronic obstructive pulmonary disease (in 2), and cystic fibrosis (in 1). Five patients (55.5%) underwent bilateral lung transplantation; one patient required bilateral re-transplantation for complications from infection. M. abscessus was isolated from the respiratory tract with a median time of 7.5 months (range: 3 days to 13 months) from transplantation. All patients were treated using a multidrug regimen, with durations ranging from 3 days to 12 months. Complications from infection included death in one patient, bronchial anastomotic dehiscence in one patient, delayed bronchial occlusions in two patients, and osteomyelitis of the knee in one patient. Median survival time from transplantation was 39 months (range: 11-96 months) and from the date of first positive culture was 58 months (range: 3-91 months). Five patients (55.5%) were cured but two had re-infections >1 year later. CONCLUSIONS: Mycobacterium abscessus infection in LTR is rare and can lead to severe complications. Eradication is difficult and usually requires prolonged combination antibiotic therapy and occasionally surgical management.

Polypropylene Mesh Infection From Surgical Site Infections Caused by Mycobacterium fortuitum.

This report highlights two cases of surgical site infections (SSIs) caused by Mycobacterium fortuitum (Mf) following abdominal mesh implantation. The first case involved an 83-year-old male experiencing non-healing erythema and wounds post-operation, which persisted despite multiple treatments, until effective management was achieved with targeted antibiotics after Mf identification. The second case concerned a female patient with a gynecological postoperative hernia, where Mf was quickly detected following SSI onset three weeks after surgery. Prompt mesh removal and appropriate antibiotic treatment led to a rapid and full recovery. These cases emphasize the importance of early detection and intervention in managing Mf infections effectively, illustrating how the timing of diagnosis can significantly influence treatment outcomes.

Mycobacterium abscessus Causes Highly Resistant Infection as a Breast Abscess.

Mycobacterium abscessus is an increasing threat to public health due to its multi-drug resistance and increasing prevalence. The pathogen most commonly causes chronic respiratory infections, but it may also invade locally through the skin and soft tissue damage caused by trauma, piercings, or tattoos. A 58-year-old African American female presented with a five-month history of recurrent abscesses in the right breast. She had previously been treated with doxycycline and ceftriaxone injections at an outside clinic with minimal improvement. Following incision and drainage, cultures and susceptibilities showed M. abscessus infection with a high level of drug resistance. Due to financial barriers, the patient received a suboptimal antibiotic regimen and required multiple surgical procedures, resulting in only temporary wound healing. At the time of this report, the patient is recovering from her fourth incision and drainage, with cultures and susceptibilities pending and discussions of a total mastectomy. M. abscessus is a highly resistant bacteria capable of causing skin and soft tissue infections of the breast. Such infections may occur without an inciting event and require extensive surgical and antimicrobial management.

Challenges in Treating Mycobacterium chelonae/abscessus Prosthetic Joint Infection.

Prosthetic joint infections (PJIs) remain a major complication of arthroplasty, most of which are caused by Staphylococcus aureus and gram-negative bacteria. Unfortunately, cultures are false negative in upward of 7 percent of patients with suspected PJIs, and commonly in infections caused by rare rapidly growing mycobacterium (RGM) species. Guidelines recommend 6 months of antimycobacterial therapy for bone diseases caused by RGM, with empiric therapy consists of an oral macrolide (clarithromycin or azithromycin) plus tobramycin and imipenem-cilastatin. Definitive treatment of PJI due to RGM should be guided by antimicrobial susceptibility, however, most microbiology laboratories are unable to differentiate between M. chelonae and M. abscessus. Furthermore, treatment of M. chelonae PJI is challenging due to multidrug resistance and the dearth of oral antibiotics for therapy. This case report investigates a patient with PJI caused by M. chelonae and M. abscessus. The initial treatment with imipenem-cilastatin was complicated by drug induced seizures, further limiting therapy options.

Mycobacterium mucogenicum bacteremia in an immunocompetent host: A case report and concise review.

Rapidly growing mycobacterium (RGM) bloodstream infections (BSI) have been described in the literature mostly in immunocompromised patients such as those with malignancies. Here, we describe a case of a RGM, Mycobacterium mucogenicum, bloodstream infection in an immunocompetent host who was receiving antibiotics via a peripherally inserted central catheter (PICC).

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.

Antimicrobial susceptibility and MIC distribution of 41 drugs against clinical isolates from China and reference strains of nontuberculous mycobacteria.

To treat nontuberculous mycobacteria (NTM) infections more optimally, further research pertaining to mycobacterial susceptibility to antimicrobial agents is required. A total of 82 species of NTM reference strains and 23 species of NTM clinical isolates were included. Minimum inhibitory concentrations (MICs) for 41 drugs were determined using the microdilution method in cation-adjusted Mueller-Hinton broth. The results showed that most of the NTM were susceptible to aminoglycosides, quinolones, three macrolides (clarithromycin, azithromycin and roxithromycin), cefmetazole, linezolid and capreomycin. Rapidly growing mycobacterium strains were additionally susceptible to cefoxitin, clofazimine, rifapentine, doxycycline, minocycline, tigecycline, meropenem and sulfamethoxazole, whereas slowly growing mycobacterium strains were additionally susceptible to rifabutin. This study on the susceptibility of NTM includes the largest sample size of Chinese clinical isolates and reference strains. NTM species-specific drug susceptibility patterns suggested that it is urgent to identify the species of NTM, to normalise the treatment of NTM infectious disease and to clarify the resistance mechanisms of NTM.

Mycobacterium Chelonae associated with rapid erosion of non-sutured laparoscopic gastric band.

INTRODUCTION: To describe a case of rapidly eroded laparoscopic placed non-sutured gastric band secondary to Mycobacterium chelonae. PRESENTATION OF CASE: A 65 year old male, who had undergone laparoscopic gastric banding two months prior for morbid obesity, presented to the clinic complaining of abdominal pain and night time fever of 4days duration. Urgent gastroscopy revealed eroded gastric band which was removed laparoscopically. DISCUSSION: M. chelonae are not uncommon in Queensland. Although the mode of acquisition of infection remains unclear, it is suspected that human disease results from environmental exposure to dirty soil and water. The patient lives in rural Queensland and uses tank water which may be contaminated with M. chelonae. CONCLUSION: It is imperative to consider environmentally acquired infection in patients with rapid erosion of non-sutured gastric band.

A Case of Mycobacterial Skin Disease Caused by Mycobacterium peregrinum, and a Review of Cutaneous Infection.

An 83-year-old Japanese man presented with a 2-month history of symptomatic nodules on the left hand. He was not in an immunocompromised condition and reported no causal events. A biopsy specimen demonstrated granulomatous tissue with mixed cell infiltration consisting of neutrophils, histiocytes, lymphocytes, and multinuclear giant cells. No bacillus was detected by PAS, acid-fast stain, immunofluorescent stain or polymerase chain reaction analysis. The isolate was found to be a rapidly growing mycobacterium after 4 weeks of incubation at 25°C on an Ogawa egg slant. Mycobacterium peregrinum was isolated by DNA-DNA hybridization analysis, 16S rRNA gene sequence, and by its production of 3-day arylsulfatase. The patient received 200 mg oral minocycline for 28 weeks. The lesion disappeared after 10 weeks of this treatment.