Clinical and Laboratory Characteristics of Patients with Nontuberculous Mycobacterium Bloodstream Infection in a Tertiary Referral Hospital in Beijing, China

Background： Nontuberculous Mycobacterium （NTM） bloodstream infection （BSI） is relatively rare. We aimed in this study to evaluate the clinical characteristics, laboratory evaluation, and outcomes of patients with NTM BSI. Methods： We retrospectively reviewed the clinical records of inpatients with NTM BSI at our institution between January 2008 and January 2015 and recorded clinical parameters including age, gender, underlying disease, clinical manifestation, organs involved with NTM disease, species of NTM, laboratory data, treatment and outcome of these patients. We also reviewed the reported cases and case series ofNTM BSI by searching PubMed, EMBASE, and Wanfang databases. Data of normal distribution were expressed by mean ~ standard deviation （SD）. Data of nonnormal distribution were expressed by median and interquartile range （IQR）. Results： Among the ten patients with NTM BSI, the median age was 51 years （IQR 29-57 years） and three patients were males. Eight patients were immunocompromised, with underlying diseases including human immunodeficiency virus （HIV） infection （one patient）, rheumatic diseases （two patients）, breast cancer （one patient）, myelodysplastic syndrome （two patients）, and aplastic anemia （two patients）. Other organ（s） involved were lung （two patients）, endocardium （two patients）, brain, spinal cord, and soft tissue （one each patient）. The median lymphocyte was 0.66 x 109/L （IQR 0.24-1 .93 × 10^9/L）. The median cluster of differentiation 4 （CD4） cell count was 179/ mm^3 （IQR 82-19/mm^3）. Five patients died （three with hematological diseases, one with breast cancer, and one with rheumatic disease）, three recovered, and two were lost to follow-up. Conclusions： We reported all cases in our hospital diagnosed with bloodstream NTM infection that was rarely reported. In this group of patients, patients usually had a high fever and could have multiple organ involvements. All patients with poor prognosis had underlying diseases.

Comparing the Genotype and Drug Susceptibilities between Mycobacterium avium and Mycobacterium intracellulare in China

Objective Mycobacterium avium （M. avium） and Mycobacterium intracellulare （M. intracellulare） are the major causative agents of nontuberculous mycobacteria （NTM）-related pulmonary infections. However, little is known about the differences in drug susceptibility profiles between these two species. Methods A total of 393 NTM isolates were collected from Shanghai Pulmonary Disease Hospital. Sequencing of partial genes was performed to identify the strains at species level. The minimum inhibitory concentration （MIC） was used to evaluate the drug susceptibility against 20 antimicrobial agents. Variable number of tandem repeat （VNTR） typing was conducted to genotype these two species. Results A total of 173 （44.0%） M. avium complex （MAC） isolates were identified, including 41 （10.4%） M. avium isolates and 132 （33.6%） M. intracellulare isolates. Clarithromycin and amikacin were the two most effective agents against MAC isolates. The Hunter-Gaston Discriminatory Index （HGDI） values for VNTR typing of M. avium and M. intracellulare isolates were 0.993 and 0.995, respectively. Levofloxacin resistance was more common among the unclustered strains than among the clustered strains of M. intracellulare. Conclusion M. intrecellulare was the most common NTM species in China. Clarithromycin and amikacin had high antimicrobial activities against MAC. VNTR typing of MAC isolates revealed a high discriminatory power. Levofloxacin resistance was associated with unclustered strains of M. intracellulare.

Mycobacterium abscessus infection after facial injection of argireline:A case report

BACKGROUND The incidence of infection with Mycobacterium abscessus(M.abscessus)has increased in recent years.This increase is partly associated with invasive cosmetic procedures.CASE SUMMARY The purpose of this case summary is to increase clinicians'awareness of M.abscessus infection and reduce mycobacterial infection caused by cosmetic procedures.We report the case of a 45-year-old woman who received acetyl hexapeptide-8(argireline)injections in the forehead and temples,and erythema,nodules,and abscesses appeared at the injection sites after one week.The pus specimens were examined by microbiological culture and confirmed to be positive for M.abscessus.Clarithromycin 500 mg twice daily and moxifloxacin 400 mg once daily were administered for 5 mo and the lesions gradually subsided.CONCLUSION We report here for the first time a case of infection with M.abscessus after argireline injection.This condition is easily misdiagnosed as a common bacterial infection.Microbiological examinations are helpful for diagnosis and standardized cosmetic procedures can prevent infection with M.abscessus.

Anti-programmed death 1 antibody in the treatment of coexistent Mycobacterium fortuitum and lung cancer: A case report

BACKGROUND Nontuberculous mycobacterium(NTM) refers to all mycobacteria except Mycobacterium tuberculosis and Mycobacterium leprae, also known as environmental Mycobacterium. The patients with lung cancer and NTM are somewhat special;the two diseases are inevitably influenced by each other. It brings difficulties and challenges to the choice of treatment. Recently, cancer immunotherapy has been considered one of the pillars for the treatment of lung cancer. However, the clinical experience in the application of immune checkpoint inhibitors is scarce for lung cancer patients with pulmonary tuberculosis, and lung cancer with NTM is even more rare. Although it ameliorates lung cancer, immunotherapy with immune checkpoint inhibitors presents complications of infectious diseases, including tuberculosis and NTM.CASE SUMMARY A 61-year-old male patient visited a doctor in May 2019. His admitting diagnoses were:(1) Cancer of the left lung with a pathological diagnosis of poorly differentiated non-small cell carcinoma, likely poorly differentiated adenocarcinoma, clinical stage Ⅲb(T3N3M0);and(2) Mycobacterium fortuitum(M. fortuitum) infection. We chose to proceed with pembrolizumab treatment. After two treatment cycles, a chest computed tomography scan showed a new irregular subpleural mass in the anterior segment of the left upper lobe of the lung, a reduction in the mediastinal enlarged lymph node, and no other obvious changes. Next, an ultrasound-guided biopsy of the new tumor was performed. Pathological examination showed that a large number of carbon particles were deposited in the alveolar tissue with histiocyte reaction and multinucleated giant cell formation. The tuberculosis(TB) specialist suggested that anti-TB therapy be combined with continued antitumor treatment. The patient continued to be treated with pembrolizumab. After 14 cycles, the lesion shrunk by 79%, there was no recurrence of M. fortuitum infection, and there were no intolerable adverse reactions.CONCLUSION We have observed that in cases of lung cancer complicated with M. fortuitum infection, opportunistic pathogen infection recurrence can be overcome, and immunotherapy is most beneficial when TB doctors and oncologists cooperate to closely observe dynamic changes in M. fortuitum and lung cancer. Treatment should be maintained with low dosage anti-TB drugs after general anti-TB chemotherapy for 1 year;this may prevent opportunistic pathogen infection recurrence during immunotherapy.

CUTANEOUS MYCOBACTERIUM MARINUM INFECTION DIAGNOSED BY PCR-RFLP ANALYSIS

Objective To identify Mycobacterium marinum （M. marinum ） inducing misdiagnosis and treatment failure. Methods The lesional specimen of patient with cutaneous M. marinum were cultivated on L6wenstein-Jensen medium. The isolate was identified by biochemical tests and polymerase chain reaction （PCR）-restriction fragment length polymorphism （RFLP） analysis of the hsp65 gene. Results Smooth and non- pigmented colonies were noted after incubation at 32 ℃ for 2 weeks. The isolate was acid-fast bacilli and confirmed as M. marinum by biochemical tests and PCR-RFLP. Conclusion For a correct diagnosis of cutaneous M. marinum infection, it is crucial for clinicians to have a high index of suspicion, obtain the history of exposure and trauma and understand growth characteristics of the organism. Compared with conventional biochemical techniques, PCR-RFLP analysis is a more rapid, accurate and reliable method for mycobacterial identification to species level.

Bilateral nontuberculous mycobacterial keratitis after laser in situ keratomileusis

Laser in situ keratomileusis （LASIK） is currently the most popular keratorefractive procedure performed worldwide with generally excellent outcomes. However, infectious keratitis after LASIK is a devastating, vision-threatening complication. The common pathogens were bacteria and fungi. Nontuberculous mycobacterium （NTM） accounted for a substantial proportion of these pathogens. Most NTM infections （86% of cases） were involved in unilateral cornea. In this study, we report six patients with bilateral NTM keratitis following LASIK.