Leshaba Tumisho Mmatumelo Seipei, Mmatli Masego, Mbelle Nontombi Marylucy, Osei Sekyere John
Department of Medical Microbiology, School of Medicine, University of Pretoria, Pretoria, South Africa.
Institute of Biomarker Research, Medical Diagnostic Laboratories, Genesis Biotechnology Group, Hamilton, New Jersey, USA.
Microbiologyopen. 2025 Aug;14(4):e70029. doi: 10.1002/mbo3.70029.
Resistance to colistin, a last-reserve antibiotic used for treating drug-resistant infections, is rising globally. We compared six commercial and in-house diagnostics-ComASP colistin, CHROMagar COL-APSE, rapid polymyxin NP (Nordmann/Poirel) test, Sensititre, MicroScan, and Vitek 2-against ISO-standard broth microdilution (BMD) using 142 Gram-negative isolates. The isolates (Enterobacterales = 110, Acinetobacter baumannii = 21, Pseudomonas aeruginosa = 11) underwent BMD and conventional multiplex PCR screening for mcr-1-mcr-5. Sensitivity, specificity, categorical agreement (CA), major error (ME), and very major error (VME) were calculated for each test. Vitek 2 and sensititre yielded the highest CA (≥ 98%) and the lowest VME (≤ 0.0%) across taxa. ComASP showed excellent performance for A. baumannii (100% sensitivity/specificity) but slightly lower CA for P. aeruginosa (73%). CHROMagar COL-APSE demonstrated acceptable sensitivity (92%) but low specificity (69%) in Enterobacterales. MicroScan had reduced specificity in Enterobacterales (87.80%). The CHROMAgar COL-APSE efficiently identified the species with their unique colours but was the least specific (68.63%), with the highest ME in Enterobacterales. The rapid NP test provided rapid results within 4 h but showed a relatively high VME (7.84%), despite maintaining an acceptable sensitivity (92.16%) and specificity (96.08%). For laboratories with automated platforms, Vitek 2 remains optimal for colistin MIC testing; Sensititre and ComASP are suitable low-cost BMD alternatives. The Rapid NP test provides a same-day screen, but confirmatory MIC testing is advised. CHROMagar COL-APSE should be used with a ≤ 1 CFU mL⁻¹ inoculum to minimise false resistance calls. Knowing the comparative performance of these different tests will assist in choosing the best test for every species, improving on efficient diagnosis and healthcare outcomes.
对黏菌素（一种用于治疗耐药性感染的最后一线抗生素）的耐药性正在全球范围内上升。我们使用142株革兰氏阴性分离株，将六种商业和内部诊断方法——ComASP黏菌素检测、CHROMagar COL-APSE、快速多黏菌素NP（诺德曼/普雷尔）检测、Sensititre、MicroScan和Vitek 2——与ISO标准肉汤微量稀释法（BMD）进行了比较。这些分离株（肠杆菌科细菌 = 110株、鲍曼不动杆菌 = 21株、铜绿假单胞菌 = 11株）进行了BMD检测以及mcr-1至mcr-5的常规多重PCR筛查。计算了每种检测方法的敏感性、特异性、分类一致性（CA）、主要错误（ME）和非常主要错误（VME）。Vitek 2和Sensititre在所有分类群中具有最高的CA（≥ 98%）和最低的VME（≤ 0.0%）。ComASP对鲍曼不动杆菌表现出优异的性能（敏感性/特异性均为100%），但对铜绿假单胞菌的CA略低（73%）。CHROMagar COL-APSE在肠杆菌科细菌中表现出可接受的敏感性（92%），但特异性较低（69%）。MicroScan在肠杆菌科细菌中的特异性降低（87.80%）。CHROMAgar COL-APSE能通过独特颜色有效鉴定菌种，但特异性最低（68.63%），在肠杆菌科细菌中的ME最高。快速NP检测在4小时内提供快速结果，但尽管保持了可接受的敏感性（92.16%）和特异性（96.08%），仍显示出相对较高的VME（7.84%）。对于拥有自动化平台的实验室，Vitek 2仍是黏菌素MIC检测的最佳选择；Sensititre和ComASP是合适的低成本BMD替代方法。快速NP检测可提供当天筛查结果，但建议进行确证性MIC检测。使用CHROMagar COL-APSE时接种量应≤1 CFU mL⁻¹，以尽量减少假耐药结果。了解这些不同检测方法的比较性能将有助于为每个菌种选择最佳检测方法，改善诊断效率和医疗结果。
