Kumar Mahadevan, Tandel Kundan, Shergill S P S, Bhalla G S, Mahajan Pooja, Swarnim Vijaya, Sahai Kavita, Gupta R M
Professor (Microbiology), Bharati Vidyapeeth Medical College, BVDUMC, Pune, India.
Classfied Specialist (Microbiology), Command Hospital (Central Command), Lucknow, India.
Med J Armed Forces India. 2023 May-Jun;79(3):267-274. doi: 10.1016/j.mjafi.2021.03.026. Epub 2021 Jun 25.
Carbapenemase producing gram-negative bacteria (GNB) has become a huge problem in majority of tertiary care centers worldwide. They are associated with very high morbidity and mortality rates, especially when they cause invasive infections. Therefore, rapid detection of these organisms is very important for prompt and adequate antibiotic therapy as well as infection control. The aim of this study was rapid detection of carbapenemase genes and thereby likely carbapenem resistance, 24-48 hours in advance, directly from the positive-flagged blood culture bottles using CHROMagar and Xpert® Carba-R.
Aspirate from positively flagged blood culture bottles was subjected to differential centrifuge. All gram-negative bacilli on gram stain from the deposit were processed in Xpert® Carba-R and inoculated on CHROMagar. The presence of genes and growth on CHROMagar was compared with carbapenem resistance on VITEK-2 Compact.
A total of 119 GNB isolates were processed. One or more of the carbapenemase genes were detected in 80 isolates. On comparison with VITEK-2 result, 92 samples showed concordance for carbapenem resistance 48 hours in advance. There was discordance in 21 isolates with 12 major errors and 09 minor errors. The sensitivity of direct Xpert® Carba-R test for rapid detection of carbapenem resistance, 48 hours in advance, was 81.42%. The sensitivity of direct CHROMagar test for accurate detection of carbapenem resistance, 24 hours in advance, was 92.06%.
The ability to detect carbapenem resistance with very high accuracy, 48 hours in advance, helps in appropriate antibiotic therapy and implementation of effective infection control practices.
产碳青霉烯酶革兰阴性菌（GNB）已成为全球大多数三级医疗中心面临的重大问题。它们与极高的发病率和死亡率相关，尤其是在引起侵袭性感染时。因此，快速检测这些微生物对于及时、充分的抗生素治疗以及感染控制非常重要。本研究的目的是使用CHROMagar和Xpert® Carba-R直接从阳性标记的血培养瓶中提前24至48小时快速检测碳青霉烯酶基因，从而可能检测到碳青霉烯耐药性。
对阳性标记血培养瓶中的吸出物进行差速离心。对沉淀物革兰染色后的所有革兰阴性杆菌进行Xpert® Carba-R检测并接种于CHROMagar。将CHROMagar上基因的存在情况及生长情况与VITEK-2 Compact上的碳青霉烯耐药性进行比较。
共处理了119株GNB分离株。在80株分离株中检测到一种或多种碳青霉烯酶基因。与VITEK-2结果比较，92个样本提前48小时显示出碳青霉烯耐药性的一致性。21株分离株存在不一致，其中12个为主要错误，9个为次要错误。直接Xpert® Carba-R检测提前48小时快速检测碳青霉烯耐药性的敏感性为81.42%。直接CHROMagar检测提前24小时准确检测碳青霉烯耐药性的敏感性为92.06%。
提前48小时以极高的准确性检测碳青霉烯耐药性的能力有助于进行适当的抗生素治疗并实施有效的感染控制措施。
