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Infective endocarditis caused by Abiotrophia defectiva is rarely encountered. A 67-year-old male transferred from a local hospital presented with severe dyspnea and pulmonary edema. Preoperative transthoracic echocardiography revealed severe mitral regurgitation with large vegetation. Blood cultures grew A. defectiva, a gram positive, nutritionally deficient streptococcus variant. Emergent mitral valve replacement through right thoracotomy was performed, and after completing six weeks of antibiotic combination therapy (vancomycin, ampicillin, and gentamicin), the patient recovered fully. Because of the need for prompt surgical treatment and long-term antibiotic therapy and lack of laboratory experience with the organism, physicians and laboratory workers should pay close attention to the possibility of A. defectiva infective endocarditis when gram positive cocci are detected in blood cultures. (Ann Clin Microbiol 2019;22:23-27)

Background: Genetic variants and haplotypes of the interleukin-10 (IL10) gene have been shown to affect clinical outcomes, including the incidence of opportunistic infections (OIs), in HIV-infected patients. This study investigated the effect of IL10 gene variants on susceptibility to OIs in HIV-infected Korean patients in the era of highly active antiretroviral therapy (HAART).Methods: Eighty-five HIV-infected patients receiving HAART were enrolled in the study. OIs were diagnosed based on the published criteria of the Korean Society for AIDS. Three promoter SNPs and four haplotype-tagging SNPs (htSNPs) of IL10 were selected and genotyped. The haplotypes were reconstructed according to the genotyping data and linkage disequilibrium (LD) status of these SNPs.Results: During the study, 38 OIs developed in 23 of the 85 patients (27.1%), at a rate of 1.7 episodes/ patient. Carrying the minor alleles at the rs1518111, rs3024490, and rs1800871 SNPs had a protective effect against OIs (adjusted P=0.035). Among the seven assessed variants, only three possible haplotypes were observed. The second most common haplotype, which was composed of the rs1518111 minor allele and the rs3021094 major allele showed a protective effect against OIs (P=0.0153).Conclusion: This study demonstrated that some IL10 genetic variants and haplotypes are associated with protective effects against OIs in the era of HAART. These data suggest the potential of two htSNPs, rs1518111 and rs3021094, as markers revealing the genetic association of IL10 in Koreans. This is the first report on the association of IL10 with OIs in HIV-infected Korean patients in the era of HAART. (Ann Clin Microbiol 2019;22:14-22)

Laboratory medicine is a specialized division that supports physicians in the care of patients by providing rapid and accurate in vitro diagnostic tests. Standardization of every component of a specific test is essential for producing accurate results. The Clinical and Laboratory Standards Institute (CLSI) was founded to develop a formal consensus process for standardization in 1968, and has been publishing standards and guidelines covering all aspects of clinical, research, and other laboratory work. CLSI guidelines are widely used around the world for standardization. The CLSI antimicrobial susceptibility testing subcommittee (AST SC) consists of 6 standing and many ad hoc working groups. Members of the AST SC review submitted proposals and suggestions, decide on approving these submissions in face-to-face meetings held twice a year, and revise CLSI documents accordingly. As these face-to-face meetings are open to anyone who registers to attend, I strongly encourage the members of our Society to attend and actively participate in document development. (Ann Clin Microbiol 2018;21:69-74)

Background: Urine culture is one of the most frequently requested tests in microbiology. Automated urine analyzers yield much infection-related information. The Sysmex UF-5000 analyzer (Sysmex, Japan) is a new flow cytometry urine analyzer capable of quantifying urinary particles, including bacteria, WBCs, and yeast-like cells (YLCs) and can provide a Gram stainability flag. In this work, we evaluated how many unnecessary urine cultures could be screened out using the UF-5000.Methods: We compared the culture results of 126 urine samples among 453 requested urine cultures (from sources other than the Urology and Nephrology departments) with urinalysis results. Urine cultures were considered positive if bacterial or YLC growth was ≥104 CFUs/mL.Results: We used urinalysis cut-off values of 50/μL and 100/μL for bacteria and YLC, respectively. Forty eight of the 126 (38.1%, or 10.6% of 453 requested) cultures were below these cut-off values and did not contain any culture-positive samples.Conclusion: Bacteria and YLC counts generated using the UF-5000 analyzer could be used to screen out negative cultures and reduce urine culture volume by ∼10% without sacrificing detection of positive cultures. (Ann Clin Microbiol 2018;21:75-79)

Background: A simple and cost-effective method is needed for the detection of rifampicin resistance in Mycobacterium tuberculosis in resource-limited settings. We suggest a broth medium-based method using 2,3-diphenyl-5-thienyl-(2)-tetrazolium chloride (STC) for detection of rifampin resistance of tubercle bacilli within a reasonable time frame.Methods: The type strain (M. tuberculosis H37Rv) and 45 cultured clinical strains of M. tuberculosis (35 rifampin-susceptible and 10 rifampin-resistant) were used. Phenotypes of rifampicin resistance were tested by the Korea Institute of tuberculosis, and confirmed by GenoType MTBDRplus (Hain Lifescience, Germany). Susceptibility tests were performed using STC-containing OADC-enriched Middlebrook 7H9 broth (BD, USA).Results: All tests were finished in 3 to 6 days. The same results were obtained with the standard and current methods for all 45 clinical isolates (100% sensitivity and specificity for resistance detection).Conclusion: The current method using STC is a good alternative for detecting M. tuberculosis rifampin resistance in a cost-effective and timely fashion, which is particularly important in resource-limited settings. (Ann Clin Microbiol 2018;21:47-50)