Non-tuberculous mycobacteria (NTM) are being recognized increasingly as the causative agents of opportunistic infections in humans. This study investigated the epidemiologic trends of NTM recovery from various clinical specimens in 2 Korean tertiary-care hospitals. We reviewed the laboratory records of patient samples cultured for mycobacteria between 2009 and 2015 at 2 tertiary-care hospitals in Korea. The medical records for patients with positive NTM samples were also reviewed. During the study period, 144,540 specimens were cultured for mycobacteria. The proportion of NTM-positive samples increased from 23.3% in 2009 to 48.2% in 2015. The 2 most frequently isolated NTM were Mycobacterium intracellulare (38.3%) and M. avium (23.1%). The number of clinically significant diseases caused by NTM in inpatients and outpatients increased from 6.8 to 12.9 per 100,000 patients over the same period. The rates of recovery of NTM from clinical specimens and the number of patients with NTM infections increased significantly (P < 0.001, testing for trend) between 2009 and 2015.

Although the prevalence of hereditary hemolytic anemia (HHA) is relatively low in Korea, it has been gradually increasing in recent decades due to increment in the proportions of hemoglobinopathies from immigrants of South East Asia, raising awareness of the disease among clinicians, and advances in diagnostic technology. As such, the red blood cell (RBC) Disorder Working Party (WP), previously called HHA WP, of the Korean Society of Hematology (KSH) developed the Korean Standard Operating Procedures (SOPs) for the diagnosis of HHA in 2007. These SOPs have been continuously revised and updated following advances in diagnostic technology [e.g., flow cytometric osmotic fragility test (FOFT) and eosin-5-maleimide (EMA) binding test], current methods for membrane protein or enzyme analysis [e.g., liquid chromatography-tandem mass spectrometry (LC-MS/MS), ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), high-performance liquid chromatography (HPLC)], and molecular genetic tests using next-generation sequencing (NGS). However, the diagnosis and treatment of HHA remain challenging as they require considerable experience and understanding of the disease. Therefore, in this new Korean Clinical Practice Guidelines for the Diagnosis of HHA, on behalf of the RBC Disorder WP of KSH, updated guidelines to approach patients suspected of HHA are summarized. NGS is proposed to perform prior to membrane protein or enzyme analysis by LC-MS/MS, UPLC-MS/MS or HPLC techniques due to the availability of gene testing in more laboratories in Korea. We hope that this guideline will be helpful for clinicians in making diagnostic decisions for patients with HHA in Korea.

Haemophagocytosis in the bone marrow of SFTS patients may be common. In SFTS endemic areas, SFTS should be one of the differential diagnoses of fever of unknown origin with haemophagocytosis in the bone marrow.

BackgroundPeptide nucleic acid (PNA) probes are artificial DNA analogues with a hydrophobic nature that can penetrate the mycobacterial cell wall. We evaluated a FISH method for simultaneous detection and identification of Mycobacterium tuberculosis (MTB) and non-tuberculous mycobacteria (NTM) in clinical respiratory specimens using differentially labeled PNA probes.MethodsPNA probes targeting the mycobacterial 16S ribosomal RNA were synthesized. The cross-reactivity of MTB- and NTM-specific probes was examined with reference strains and 10 other frequently isolated bacterial species. A total of 140 sputum specimens were analyzed, comprising 100 MTB-positive specimens, 21 NTM-positive specimens, and 19 MTB/NTM-negative specimens; all of them were previously confirmed by PCR and culture. The PNA FISH test results were graded by using the United States Centers for Disease Control and Prevention-recommended scale and compared with the results from the fluorochrome acid-fast bacterial stain.ResultsThe MTB- and NTM-specific PNA probes showed no cross-reactivity with other tested bacterial species. The test results demonstrated 82.9% agreement with the culture results with diagnostic sensitivity of 80.2% and diagnostic specificity of 100.0% (kappa=0.52, 95% confidence interval: 0.370-0.676).ConclusionsDual-color PNA FISH showed high specificity for detecting and identifying mycobacteria in clinical specimens. However, because of its relatively low sensitivity, this method could be more applicable to culture confirmation. In application to direct specimens, the possibility of false-negative results needs to be considered.

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