Department of Microbiology, Immunology, and Infectious Diseases, College of Medicine & Medical Sciences, Arabian Gulf University, Manama, Bahrain.
Head of Department of Pathology, Microbiology Section, Al-Salmaniya Medical Complex, Manama, Bahrain.
Indian J Med Microbiol. 2024 Jul-Aug;50:100640. doi: 10.1016/j.ijmmb.2024.100640. Epub 2024 Jun 19.
Acinetobacter baumannii is a serious health concern worldwide, causing high mortality rates and limited medical therapy options. Carbapenem resistance is a significant problem in Acinetobacter baumannii isolates. The synthesis of acquired carbapenemases, such as oxacillinases, IMP, NDM, VIM, and KPC enzymes, causes carbapenem resistance.
A total of 106 non-repetitive, Acinetobacter baumannii isolates were collected from four major hospitals in Bahrain including 78 carbapenem-resistant Acinetobacter baumannii (CRAB), and 28 carbapenem-susceptible Acinetobacter baumannii (CSAB) isolates. Three phenotypic tests were investigated in this study: including CARBA NP, modified carbapenem inactivation method (mCIM)/EDTA-CIM (eCIM), and modified Hodge test (MHT).
CARBA NP was positive in 50 tested CRAB isolates (100%), and the sensitivity was 100%. The MHT was positive in 73/106 isolates (68.8%), while the sensitivity and specificity of the MHT were 77.6% and 100%. Moreover, only 38/106 (35.8%) isolates were positive for mCIM/eCIM. The sensitivity and specificity of mCIM were 40.4% and 100%.
CARBA NP was ideal for phenotypic detection of carbapenemase production, followed by MHT. The m/eCIM demonstrated a lower detection rate in CRAB. Consequently, combining tests would be more accurate. The mCIM/eCIM can easily distinguish between MBLs and serine-carbapenemases due to the frequent co-production of these enzymes in A. baumannii. In hospital setups where molecular characterization tests are not available, CARBA NP seems to be an alternative test in combination with MHT or mCIM/eCIM.
鲍曼不动杆菌是全球范围内严重的健康问题，导致高死亡率和有限的医疗治疗选择。碳青霉烯类耐药是鲍曼不动杆菌分离株的一个重大问题。获得性碳青霉烯酶的合成，如 oxacillinases、IMP、NDM、VIM 和 KPC 酶，导致碳青霉烯类耐药。
本研究共收集了来自巴林四家主要医院的 106 例非重复鲍曼不动杆菌分离株，包括 78 例碳青霉烯类耐药鲍曼不动杆菌（CRAB）和 28 例碳青霉烯类敏感鲍曼不动杆菌（CSAB）。本研究共研究了三种表型检测方法：CARBA NP、改良碳青霉烯灭活法（mCIM）/EDTA-CIM（eCIM）和改良 Hodge 试验（MHT）。
50 例 CRAB 检测中 CARBA NP 阳性（100%），敏感性为 100%。MHT 在 106 例分离株中阳性率为 73/106（68.8%），敏感性和特异性分别为 77.6%和 100%。此外，仅 38/106（35.8%）分离株 mCIM/eCIM 阳性。mCIM 的敏感性和特异性分别为 40.4%和 100%。
CARBA NP 是检测碳青霉烯酶产生的理想表型检测方法，其次是 MHT。m/eCIM 对 CRAB 的检测率较低。因此，联合检测将更准确。mCIM/eCIM 可因 A.baumannii 中这些酶的频繁共产生而易于区分 MBLs 和丝氨酸碳青霉烯酶。在没有分子特征检测的医院环境中，CARBA NP 似乎是与 MHT 或 mCIM/eCIM 联合使用的替代检测方法。
