Successful Treatment of Peritoneal Dialysis-related Peritonitis due to Mycobacterium iranicum

Metagenomic next-generation sequencing assistance in identifying Mycobacterium iranicum pulmonary infection: A case report

Nontuberculous mycobacteria (NTM) are important opportunistic pathogens in humans, mostly affecting the lungs, and potentially causing progressive disease in individuals with underlying diseases. The prevalence of NTM infections is increasing worldwide. However, Mycobacterium iranicum (M. iranicum) infections are less common. Here we report a 65-year-old female who developed pneumonia caused by Mycobacterium iranicum, which was detected in bronchoalveolar lavage fluid (BALF) through metagenomic next-generation sequencing (mNGS). The patient was treated with moxifloxacin, doxycycline, and sulfamethoxazole/trimethoprim. Symptoms were relieved and lung abnormalities were shown to be partially absorbed on the follow-up chest computed tomography (CT) scans. As we know, this is the first case of Mycobacterium iranicum pulmonary infection identified by mNGS in BALF.

Assessing Antibiotic-Resistant Genes in University Dormitory Washing Machines

University dormitories represent densely populated environments, and washing machines are potential sites for the spread of bacteria and microbes. However, the extent of antibiotic resistance gene (ARG) variation in washing machines within university dormitories and their potential health risks are largely unknown. To disclose the occurrence of ARGs and antibiotic-resistant bacteria from university dormitories, we collected samples from washing machines in 10 dormitories and used metagenomic sequencing technology to determine microbial and ARG abundance. Our results showed abundant microbial diversity, with Proteobacteria being the dominant microorganism that harbors many ARGs. The majority of the existing ARGs were associated with antibiotic target alteration and efflux, conferring multidrug resistance. We identified tnpA and IS91 as the most abundant mobile genetic elements (MGEs) in washing machines and found that Micavibrio aeruginosavorus, Aquincola tertiaricarbonis, and Mycolicibacterium iranicum had high levels of ARGs. Our study highlights the potential transmission of pathogens from washing machines to humans and the surrounding environment. Pollution in washing machines poses a severe threat to public health and demands attention. Therefore, it is crucial to explore effective methods for reducing the reproduction of multidrug resistance.

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.

Mycobacterium iranicum pulmonary disease in an elderly patient with extensive usual interstitial pneumonia: Case report

We report the first case of Mycobacterium iranicum pulmonary disease in an elderly patient with extensive usual interstitial pneumonia and traction bronchiectasis. He was treated with oral doxycycline, ciprofloxacin, and sulfamethoxazole/trimethoprim daily for 9 months. This was associated with eradication of the microorganism in the sputum and steady weight gain.

Peritoneal Dialysis Guidelines 2019 Part 1 (Position paper of the Japanese Society for Dialysis Therapy)

Approximately 10 years have passed since the Peritoneal Dialysis Guidelines were formulated in 2009. Much evidence has been reported during the succeeding years, which were not taken into consideration in the previous guidelines, e.g., the next peritoneal dialysis PD trial of encapsulating peritoneal sclerosis (EPS) in Japan, the significance of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), the effects of icodextrin solution, new developments in peritoneal pathology, and a new international recommendation on a proposal for exit-site management. It is essential to incorporate these new developments into the new clinical practice guidelines. Meanwhile, the process of creating such guidelines has changed dramatically worldwide and differs from the process of creating what were “clinical practice guides.” For this revision, we not only conducted systematic reviews using global standard methods but also decided to adopt a two-part structure to create a reference tool, which could be used widely by the society’s members attending a variety of patients. Through a working group consensus, it was decided that Part 1 would present conventional descriptions and Part 2 would pose clinical questions (CQs) in a systematic review format. Thus, Part 1 vastly covers PD that would satisfy the requirements of the members of the Japanese Society for Dialysis Therapy (JSDT). This article is the duplicated publication from the Japanese version of the guidelines and has been reproduced with permission from the JSDT.

The influence of non-tuberculous mycobacteria on the interaction of opportunistic microorganisms with erythrocytes

Getting into a weakened organism, non-tuberculosis mycobacteria (NTMB) contact not only with the cells of the microorganism but also with the microflora of the human body; however, these interactions are poorly understood. The purpose of this work was to study the effect of NTMB supernatants on the properties of conditionally pathogenic microorganisms in their interaction with red blood cells. We used strains of non-tuberculous mycobacteria Mycobacterium iranicum and M. rutilum, as well as strains of Staphylococcus epidermidis and Escherichia coli. Using the fluorescence in situ hybridisation (FISH) method, the processes of adhesion to the surface of erythrocytes and the intra-erythrocyte penetration of cells of S. epidermidis and E. coli under the influence of NTMB supernatants were studied. To study changes in the haemoglobin molecule under the action of the supernatants of NTMB, spectral analysis was performed. Statistical processing was performed using STATISTIKA 6.0. The results showed that the supernatants of M. iranicum and M. rutilum increased the adhesion of conditionally pathogenic bacteria with a low level of AntiHbA to the surface of erythrocytes by 3-4 times. It also increased the intra-erythrocyte penetration of cells of S. epidermidis and E. coli relative to the control values. As a result of studying the haemoglobin spectrum of erythrocytes under the influence of M. iranicum, a decrease in the optical density values of oxyhaemoglobin by a factor of 2 relative to the values in the control sample was noted. Thus, the supernatants of NTMB have a multidirectional effect on the interaction of opportunistic microorganisms with erythrocytes, increasing the adhesive activity and the penetration of cells into the erythrocytes, as well as reducing the optical density of oxyhaemoglobin.

Mycobacterium iranicum bacteremia and hemophagocytic lymphohistiocytosis: a case report

BACKGROUND

Mycobacterium iranicum has recently been recognised as an opportunistic human pathogen. Although infectious conditions represent frequent triggers for hemophagocytic lymphohistiocytosis, non-tuberculous mycobacterial infections are rarely associated with this entity. To this date, M. iranicum infection has never been reported in France, has never been associated with hemophagocytic lymphohistiocytosis and has never been found to be multi-resistant on standardized antimicrobial susceptibility testing.

CASE PRESENTATION

We report a case of a French Caucasian man with secondary hemophagocytic lymphohistiocytosis in the context of M. iranicum bacteraemia and Hodgkin's disease. We review available data concerning M. iranicum antimycobacterial susceptibility testing and treatment outcomes. We also review the association between hemophagocytic lymphohistiocytosis and non-tuberculous mycobacterial infections.

CONCLUSION

Interpretation of M. iranicum positive cultures remains a clinical challenge and non-tuberculous mycobacterial infections need to be considered in secondary hemophagocytic lymphohistiocytosis differential diagnosis.

Mycobacterium iranicum septic arthritis and tenosynovitis

Mycobacterium iranicum is a newly reported nontuberculous mycobacterial (NTM) species that has been previously isolated in twelve patients. Our report presents the thirteenth known case of M. iranicum, which caused septic arthritis of the right third proximal interphalangeal joint and associated tenosynovitis in a 39-year-old female following a rose thorn injury.

Mycobacterial Taxonomy

This article summarizes the most recent (since 2012) taxonomic changes in the genus Mycobacterium Only those mycobacteria that have been isolated from human specimens are included in this summary.