1.Performance validation of the BD MAX Enteric Parasite Panel using simulated samples in low endemic regions
Bosung PARK ; Eun Jeong WON ; Heungsup SUNG ; Mi-Na KIM
Parasites, Hosts and Diseases 2025;63(1):50-56
Molecular diagnostics are essential for detecting intestinal parasites, but evaluating clinical samples from low endemic areas, including Korea, is challenging. We tested the performance of the BD MAX Enteric Parasite Panel in simulated samples for clinical use. Simulated samples were prepared with residual stool samples to confirm the diagnostic performance of the kits. Standard materials for Cryptosporidium parvum, Giardia lamblia, and Entamoeba histolytica were obtained for assessment. Limit of detection was determined by diluting standard materials into multiple concentrations and testing each in duplicate. Repeatability was assessed by retesting all samples twice. Accuracy was evaluated by comparing BD MAX System results with intended results. The limit of detection values obtained using standard materials were 781 cysts/ml, 6,250 oocysts/ml, and 125 DNA copies/ml for G. lamblia, C. parvum, and E. histolytica, respectively. Simulated G. lamblia-positive stool samples with concentrations above 6,250 cysts/ml consistently yielded positive results (100% concordance). However, C. parvum-positive stool samples at 6,250 oocysts/ml showed 50% concordance initially and 75% after retesting. At 62,500 oocysts/ml, the concordance rates were 89% initially and 100% after retesting. Overall agreement was 95.2%, but that for C. parvum was relatively low (82.4%). The diagnostic performances were 87.8% of sensitivity and 100% of specificity. Despite the limited clinical samples, BD MAX Enteric Parasite Panel showed good performance for clinical use, and spiked samples proved useful for evaluating protozoan PCR in low-incidence regions.
2.Performance validation of the BD MAX Enteric Parasite Panel using simulated samples in low endemic regions
Bosung PARK ; Eun Jeong WON ; Heungsup SUNG ; Mi-Na KIM
Parasites, Hosts and Diseases 2025;63(1):50-56
Molecular diagnostics are essential for detecting intestinal parasites, but evaluating clinical samples from low endemic areas, including Korea, is challenging. We tested the performance of the BD MAX Enteric Parasite Panel in simulated samples for clinical use. Simulated samples were prepared with residual stool samples to confirm the diagnostic performance of the kits. Standard materials for Cryptosporidium parvum, Giardia lamblia, and Entamoeba histolytica were obtained for assessment. Limit of detection was determined by diluting standard materials into multiple concentrations and testing each in duplicate. Repeatability was assessed by retesting all samples twice. Accuracy was evaluated by comparing BD MAX System results with intended results. The limit of detection values obtained using standard materials were 781 cysts/ml, 6,250 oocysts/ml, and 125 DNA copies/ml for G. lamblia, C. parvum, and E. histolytica, respectively. Simulated G. lamblia-positive stool samples with concentrations above 6,250 cysts/ml consistently yielded positive results (100% concordance). However, C. parvum-positive stool samples at 6,250 oocysts/ml showed 50% concordance initially and 75% after retesting. At 62,500 oocysts/ml, the concordance rates were 89% initially and 100% after retesting. Overall agreement was 95.2%, but that for C. parvum was relatively low (82.4%). The diagnostic performances were 87.8% of sensitivity and 100% of specificity. Despite the limited clinical samples, BD MAX Enteric Parasite Panel showed good performance for clinical use, and spiked samples proved useful for evaluating protozoan PCR in low-incidence regions.
3.Can Acanthamoeba keratitis be properly diagnosed without culture in the real-world clinical microbiology laboratory?: a case report
Bosung PARK ; Ho Seok CHUNG ; Eun Jeong WON ; Heungsup SUNG ; Mi-Na KIM
Annals of Clinical Microbiology 2024;27(2):149-153
Acanthamoeba species are ubiquitous, free-living organisms found in the environment. They can cause a sight-threatening cornea disease, termed Acanthamoeba keratitis, and are often misdiagnosed, causing delayed administration of the correct treatment. Herein, we report a case of Acanthamoeba keratitis diagnosed without culture. A 12-year-old girl with a history of wearing contact lenses presented with complaints of pain, irritation, and hyperemia in the left eye. Corneal scraping-smeared slide, and liquids with contact lenses were submitted to the clinical microbiology laboratory. Cultures of Acanthamoeba spp. were not available; thus, they were stained with calcofluor white. The isolation of Acanthamoeba from the corneal scraping allowed the detection of trophozoites and cysts based on their morphological characteristics. PCR targeting the 18s rRNA gene and subsequent sequencing revealed 99% identity with the Acanthamoeba spp. Although it is challenging to find real-world evidence of Acanthamoeba in clinical microbiology without using culture methods, this case underscores the need for clinical microbiology laboratories to maintain their inspection capabilities.
4.Verification of the Mycoplasma IST3 for urogenital mycoplasma culture in comparison to the Mycoplasma IST2
Seungtaek LIM ; Seunghwan SEOL ; Eun Jeong WON ; Bosung PARK ; Heungsup SUNG ; Mi-Na KIM
Annals of Clinical Microbiology 2024;27(3):205-214
Background:
Unlike the Mycoplasma IST2 kit (bioMérieux), the Mycoplasma IST3 kit has been updated to comply with the standardized antimicrobial susceptibility test (AST) method for Ureaplasma spp. (Up) and Mycoplasma hominis (Mh). We aimed to verify the use of the Mycoplasma IST3 kit for genital mycoplasma cultures.
Methods:
From September 2023 to January 2024, the R1 medium remaining after inoculation with IST2 was refrigerated until the next day. For IST2-positive samples, 300 μL of residual R1 medium was inoculated into the IST3. Species identification, enumeration, and AST results obtained using IST3 were compared with those obtained using IST2.
Results:
A total of 48 IST2-positive samples were inoculated into IST3, including 35, 1, and 12 Up-only, Mh-only, and both Up- and Mh-positive samples, respectively. Among Up-only samples, 2.8%, 91.4%, and 100.0% were susceptible to ciprofloxacin, tetracycline, and erythromycin, respectively. With IST3, 45 (93.8%) samples grew genital mycoplasmas; 42 (89.4%) of the 47 Up-positive samples and 6 (46.2%) of the 13 Mh-positive samples showed growth of the same organisms. All seven samples that failed to grow Mh were from mixed cultures, of which four Mh concentrations of < 104 /mL. Up was susceptible to levofloxacin, tetracycline, and erythromycin at the rates of 64.3 %, 88.1 %, and 95.2 %, respectively.
Conclusion
IST3 showed good performance in detecting genital Mycoplasma except for its tendency to not detect Mh of low concentrations in mixed cultures. IST3 is preferable to IST2 because it can accurately screen for erythromycin resistance in Up and reduce falseresistances for fluoroquinolone.
5.Performance validation of the BD MAX Enteric Parasite Panel using simulated samples in low endemic regions
Bosung PARK ; Eun Jeong WON ; Heungsup SUNG ; Mi-Na KIM
Parasites, Hosts and Diseases 2025;63(1):50-56
Molecular diagnostics are essential for detecting intestinal parasites, but evaluating clinical samples from low endemic areas, including Korea, is challenging. We tested the performance of the BD MAX Enteric Parasite Panel in simulated samples for clinical use. Simulated samples were prepared with residual stool samples to confirm the diagnostic performance of the kits. Standard materials for Cryptosporidium parvum, Giardia lamblia, and Entamoeba histolytica were obtained for assessment. Limit of detection was determined by diluting standard materials into multiple concentrations and testing each in duplicate. Repeatability was assessed by retesting all samples twice. Accuracy was evaluated by comparing BD MAX System results with intended results. The limit of detection values obtained using standard materials were 781 cysts/ml, 6,250 oocysts/ml, and 125 DNA copies/ml for G. lamblia, C. parvum, and E. histolytica, respectively. Simulated G. lamblia-positive stool samples with concentrations above 6,250 cysts/ml consistently yielded positive results (100% concordance). However, C. parvum-positive stool samples at 6,250 oocysts/ml showed 50% concordance initially and 75% after retesting. At 62,500 oocysts/ml, the concordance rates were 89% initially and 100% after retesting. Overall agreement was 95.2%, but that for C. parvum was relatively low (82.4%). The diagnostic performances were 87.8% of sensitivity and 100% of specificity. Despite the limited clinical samples, BD MAX Enteric Parasite Panel showed good performance for clinical use, and spiked samples proved useful for evaluating protozoan PCR in low-incidence regions.
6.Performance validation of the BD MAX Enteric Parasite Panel using simulated samples in low endemic regions
Bosung PARK ; Eun Jeong WON ; Heungsup SUNG ; Mi-Na KIM
Parasites, Hosts and Diseases 2025;63(1):50-56
Molecular diagnostics are essential for detecting intestinal parasites, but evaluating clinical samples from low endemic areas, including Korea, is challenging. We tested the performance of the BD MAX Enteric Parasite Panel in simulated samples for clinical use. Simulated samples were prepared with residual stool samples to confirm the diagnostic performance of the kits. Standard materials for Cryptosporidium parvum, Giardia lamblia, and Entamoeba histolytica were obtained for assessment. Limit of detection was determined by diluting standard materials into multiple concentrations and testing each in duplicate. Repeatability was assessed by retesting all samples twice. Accuracy was evaluated by comparing BD MAX System results with intended results. The limit of detection values obtained using standard materials were 781 cysts/ml, 6,250 oocysts/ml, and 125 DNA copies/ml for G. lamblia, C. parvum, and E. histolytica, respectively. Simulated G. lamblia-positive stool samples with concentrations above 6,250 cysts/ml consistently yielded positive results (100% concordance). However, C. parvum-positive stool samples at 6,250 oocysts/ml showed 50% concordance initially and 75% after retesting. At 62,500 oocysts/ml, the concordance rates were 89% initially and 100% after retesting. Overall agreement was 95.2%, but that for C. parvum was relatively low (82.4%). The diagnostic performances were 87.8% of sensitivity and 100% of specificity. Despite the limited clinical samples, BD MAX Enteric Parasite Panel showed good performance for clinical use, and spiked samples proved useful for evaluating protozoan PCR in low-incidence regions.
7.Performance validation of the BD MAX Enteric Parasite Panel using simulated samples in low endemic regions
Bosung PARK ; Eun Jeong WON ; Heungsup SUNG ; Mi-Na KIM
Parasites, Hosts and Diseases 2025;63(1):50-56
Molecular diagnostics are essential for detecting intestinal parasites, but evaluating clinical samples from low endemic areas, including Korea, is challenging. We tested the performance of the BD MAX Enteric Parasite Panel in simulated samples for clinical use. Simulated samples were prepared with residual stool samples to confirm the diagnostic performance of the kits. Standard materials for Cryptosporidium parvum, Giardia lamblia, and Entamoeba histolytica were obtained for assessment. Limit of detection was determined by diluting standard materials into multiple concentrations and testing each in duplicate. Repeatability was assessed by retesting all samples twice. Accuracy was evaluated by comparing BD MAX System results with intended results. The limit of detection values obtained using standard materials were 781 cysts/ml, 6,250 oocysts/ml, and 125 DNA copies/ml for G. lamblia, C. parvum, and E. histolytica, respectively. Simulated G. lamblia-positive stool samples with concentrations above 6,250 cysts/ml consistently yielded positive results (100% concordance). However, C. parvum-positive stool samples at 6,250 oocysts/ml showed 50% concordance initially and 75% after retesting. At 62,500 oocysts/ml, the concordance rates were 89% initially and 100% after retesting. Overall agreement was 95.2%, but that for C. parvum was relatively low (82.4%). The diagnostic performances were 87.8% of sensitivity and 100% of specificity. Despite the limited clinical samples, BD MAX Enteric Parasite Panel showed good performance for clinical use, and spiked samples proved useful for evaluating protozoan PCR in low-incidence regions.