Characterization of the first report of Mycobacterium timonense infecting an HIV patient in an Ecuadorian hospital

First Case Reports of Nontuberculous Mycobacterial (NTM) Lung Disease in Ecuador: Important Lessons to Learn

Nontuberculous mycobacteria (NTM) lung infections are often misdiagnosed as tuberculosis, which can lead to ineffective antibiotic treatments. In this report, we present three cases of NTM lung infections in Ecuador that were initially diagnosed and treated as tuberculosis based on the results of sputum smear microscopy. The patients, all male, included two immunocompetent individuals and one HIV-positive subject. Unfortunately, sputum culture was not initiated until late in the course of the disease and the cause of the lung infection, Mycobacterium avium complex (MAC), was only identified after the patients had either passed away or were lost to follow-up. These cases are the first documented cases of NTM lung infections in the English medical literature from Ecuador. We emphasize the importance of accurate diagnosis of NTM infections by culture and identification to species level. Sputum smear staining alone cannot differentiate between mycobacterial species, which can lead to misidentification and ineffective treatments. Additionally, reporting NTM pulmonary disease as a notifiable disease to national TB control programs is recommended to obtain accurate prevalence data. These data are critical in determining the importance of this public health problem and the necessary actions needed to address it.

Identification and drug susceptibility testing of the subspecies of Mycobacterium avium complex clinical isolates in mainland China

OBJECTIVES

The Mycobacterium avium complex (MAC), comprising a series of subspecies, has a worldwide distribution, with differences in drug susceptibility among subspecies. This study aimed to assess the composition of MAC and susceptibility differences among subspecies in mainland China.

METHODS

A total of 287 MAC clinical strains were included in the study. Multitarget sequences were applied to accurately identify subspecies, and a microdilution method was used to evaluate minimum inhibitory concentrations (MICs) among subspecies using Sensititre SLOMYCO plates.

RESULTS

Mycobacterium intracellular (N = 169), Mycobacterium avium (N = 52), Mycobacterium chimaera (N = 22), Mycobacterium marseillense (N = 25), Mycobacterium colombiense (N = 14), Mycobacterium yongonense (N = 4), Mycobacterium vulneris (N = 3) and Mycobacterium timonense (N = 2) were isolated from MAC. Clarithromycin, amikacin and rifabutin showed lower MIC₅₀ and MIC₉₀ values than other drugs, and the resistance rates of clarithromycin, amikacin, linezolid and moxifloxacin were 6.3%, 10.5%, 51.9% and 46.3%, respectively. The resistance rates of clarithromycin and moxifloxacin in the initial treatment group were significantly lower than those in the retreatment group (4.09% vs. 12.94%; 30.41% vs. 75.29%; P < 0.05). Drug susceptibility differences were observed in clarithromycin and moxifloxacin among the five major subspecies (P < 0.05); however, those statistically significant differences disappeared when MACs were divided into two groups according to previous anti-tuberculosis (anti-TB) treatment history.

CONCLUSION

This study revealed that MAC, primarily comprising M. intracellulare, was susceptible to clarithromycin, amikacin and rifabutin. Drug susceptibility among subspecies did not exhibit intrinsic differences in our study. Previous anti-TB treatment patients are more resistant to drugs; thus, attention should be given to those patients in the clinic.

Mycobacterium abscessus subspecies abscessus infection associated with cosmetic surgical procedures: Cases series

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Mycobacterium abscessus is a drug-resistant nontuberculous mycobacterium (NTM).

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Cutaneous & subcutaneous NTM infections post-cosmetic surgery are poorly diagnosed.

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Initial surgical evaluation facilitates early suspicion of M. abscessus infection.

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Rapidly evolving infection & negative culture/antibiotic response are indicators.

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Amikacin, imipenem, & clarithromycin combination may treat M. abscessus infection.

Background

Mycobacterium abscessus is one of the most pathogenic and drug-resistant opportunistic microorganisms among the nontuberculous mycobacteria (NTM) involved in skin and soft tissue infections (SSTI) associated with cosmetic surgical procedures. However, NTM infection is often wrongly diagnosed initially causing prolonged suffering. Here is described the author’s experience working with patients who developed M. abscessus SSTI after cosmetic procedures.

Methods

Patients who developed NTM infection after undergoing cosmetic procedures, and who presented at the Hospital Metropolitano and Hospital Vozandes (Quito, Ecuador) between 2013–2016. A review of patient medical records was performed.

Results

Five patients with culture proven M. abscessus subspecies abscessus SSTI after cosmetic surgeries were identified. All patients were treated with aggressive surgical debridement and antibiotics.

Conclusions

A rapidly spreading wound infection presenting two or more weeks after a cosmetic procedure that fails to respond to standard antimicrobial therapy should raise suspicion for NTM infection. Samples for acid-fast bacilli smear, cultures, and PCR from infected tissue should be taken. Surgical drainage and debridement are recommended along with a long course of antibiotics. In the absence of clinical trials, a combination of amikacin, imipenem, and clarithromycin may be an adequate initial treatment for M. abscessus subspecies abscessus SSTI in immunocompetent patients.

HIV and mycobacteria

The importance of mycobacteria as opportunistic pathogens, particularly members of the M. avium complex (MAC), in patients with progressive HIV infection was recognized early in the AIDS epidemic. It took longer to appreciate the global impact and devastation that would result from the deadly synergy that exists between HIV and M. tuberculosis. This HIV/M. tuberculosis co-pandemic is ongoing and claiming millions of lives every year. In addition to MAC, a number of other non-tuberculous mycobacteria have been recognized as opportunistic pathogens in HIV-infected individuals; some of these are more commonly encountered (e.g., M. kansasii) than others (M. haemophilum and M. genevense). Finally, there are challenges to concomitantly treating the HIV and the infecting Mycobacterium species, because of antimicrobial resistance, therapeutic side-effects and the complex pharmacologic interactions of the antiretroviral and antimycobacterial multidrug therapy.

Avian Mycobacteriosis: Still Existing Threat to Humans

The nontuberculous mycobacteria are typically environmental organisms residing in soil and water. These microorganisms can cause a wide range of clinical diseases; pulmonary disease is most frequent, followed by lymphadenitis in children, skin and soft tissue disease, and rare extra pulmonary or disseminated infections. Mycobacterium avium complex is the second most common cause of pulmonary mycobacterioses after M. tuberculosis. This review covers the clinical and laboratory diagnosis of infection caused by the members of this complex and particularities for the treatment of different disease types and patient populations.

Panniculitis caused by Mycobacterium monacense mimicking erythema induratum: a case in Ecuador

We report the first case of recently characterized species M. monacense associated with chronic nodular vasculitis, infecting a young woman. This case represents the first isolation of M. monacense from Ecuador. The isolate was identified by conventional and molecular techniques.

Microbiological features and clinical relevance of new species of the genus Mycobacterium

Nontuberculous mycobacteria (NTM) are present in the environment, mainly in water, and are occasionally responsible for opportunistic infections in humans. Despite the fact that NTM are characterized by a moderate pathogenicity, the diseases caused by NTM at various body sites are increasing on a worldwide level. Among over 150 officially recognized NTM species, only two or three dozen are familiar to clinicians, and even to most microbiologists. In this paper, approximately 50 new species described in the last 8 years are reviewed, and their role in human infections is assessed on the basis of reported clinical cases. The small number of reports concerning most of the "new" mycobacterial species is responsible for the widespread conviction that they are very rare. Their role is actually largely underestimated, mainly because they often remain unrecognized and misidentified. Aiming to minimize such bias, emphasis has been placed on more common identification pitfalls. Together with new NTM, new members of the Mycobacterium tuberculosis complex described in the last few years are also an object of the present review.

Role of the horizontal gene exchange in evolution of pathogenic Mycobacteria

BACKGROUND

Mycobacterium tuberculosis is one of the most dangerous human pathogens, the causative agent of tuberculosis. While this pathogen is considered as extremely clonal and resistant to horizontal gene exchange, there are many facts supporting the hypothesis that on the early stages of evolution the development of pathogenicity of ancestral Mtb has started with a horizontal acquisition of virulence factors. Episodes of infections caused by non-tuberculosis Mycobacteria reported worldwide may suggest a potential for new pathogens to appear. If so, what is the role of horizontal gene transfer in this process?

RESULTS

Availing of accessibility of complete genomes sequences of multiple pathogenic, conditionally pathogenic and saprophytic Mycobacteria, a genome comparative study was performed to investigate the distribution of genomic islands among bacteria and identify ontological links between these mobile elements. It was shown that the ancient genomic islands from M. tuberculosis still may be rooted to the pool of mobile genetic vectors distributed among Mycobacteria. A frequent exchange of genes was observed between M. marinum and several saprophytic and conditionally pathogenic species. Among them M. avium was the most promiscuous species acquiring genetic materials from diverse origins.

CONCLUSIONS

Recent activation of genetic vectors circulating among Mycobacteria potentially may lead to emergence of new pathogens from environmental and conditionally pathogenic Mycobacteria. The species which require monitoring are M. marinum and M. avium as they eagerly acquire genes from different sources and may become donors of virulence gene cassettes to other micro-organisms.

Evaluation of Vitek MS for rapid classification of clinical isolates belonging to Mycobacterium avium complex

We evaluated the ability of the Vitek MS system to classify clinical pulmonary Mycobacterium avium complex isolates compared to multilocus sequence analysis. Vitek MS accurately identified 55% of the isolates as M. avium and 18% as M. intracellulare, but misidentified 24 (27%) Mycobacterium chimaera isolates as Mycobacterium intracellulare.