Department of Microbiology, King George's Medical University, Lucknow, Uttar Pradesh, India.
Department of Critical Care Medicine, King George's Medical University, Lucknow, Uttar Pradesh, India.
PLoS One. 2021 Sep 8;16(9):e0256308. doi: 10.1371/journal.pone.0256308. eCollection 2021.
Ventilator-associated pneumonia (VAP) may be a life threatening nosocomial infection encountered in intensive care units. Currently the emergence of carbapenem-resistant Gram-negative pathogens has become worrisome threat worldwide.
Endotracheal aspirates samples were collected from patients who were under mechanical ventilation for > 48 h. The bacterial isolates were identified by MALDI-TOF-MS and antibiotic susceptibility testing performed. All carbapenem resistant isolates were tested by Modified Hodge test (MHT), modified carbapenem inactivation method (mCIM), and EDTA-CIM (eCIM) and PCR were performed to detect blaIMP, blaVIM and blaNDM producing MBL genes.
VAP occurred in 172/353(48.7%), 23.3% had early-onset VAP and 76.7% had late-onset VAP. Males (69.2%) were found to suffer more from VAP. Prior antibiotic therapy, CPI>6, prior surgery and tracheostomy were associated with VAP. The mortality in VAP (58.1%) contrasted with non-VAP (40%). 99/169 (58.6%) Gram-negative isolates were resistant to carbapenems. Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae were common pathogens found in late onset VAP, whereas K. pneumoniae, A. baumannii and Staphylococcus aureus were common in early onset VAP. The PCR results detected blaNDM in 37/172(21.5%) and blaVIM in 30/172(17.4%); 15/172(8.7%) isolates carried both genes.
The blaNDM-1 and blaVIM genes are the main antibiotic-resistance genes that induce resistance patterns to carbapenems in VAP, highlighting CRE strains of potential public health concern and therapeutic challenge. Diagnostic laboratories in India must get on high caution for early MBL detection as it may limit the wide dispersal of MBL genes.
呼吸机相关性肺炎（VAP）可能是重症监护病房中危及生命的医院获得性感染。目前，碳青霉烯类耐药革兰氏阴性病原体的出现已成为全球令人担忧的威胁。
从接受机械通气超过 48 小时的患者中采集气管内抽吸物样本。通过 MALDI-TOF-MS 鉴定细菌分离株，并进行抗生素敏感性试验。所有碳青霉烯类耐药分离株均进行改良霍格试验（MHT）、改良碳青霉烯类灭活法（mCIM）和 EDTA-CIM（eCIM）检测，并通过 PCR 检测 blaIMP、blaVIM 和 blaNDM 产生的 MBL 基因。
353 例患者中发生 VAP172 例（48.7%），早发性 VAP 占 23.3%，晚发性 VAP 占 76.7%。男性（69.2%）更易患 VAP。先前的抗生素治疗、CPI>6、先前的手术和气管切开术与 VAP 相关。VAP 的死亡率（58.1%）与非 VAP（40%）相比差异显著。169 株革兰氏阴性分离株中 99 株（58.6%）对碳青霉烯类耐药。鲍曼不动杆菌、铜绿假单胞菌和肺炎克雷伯菌是晚发性 VAP 常见的病原体，而早发性 VAP 中常见的病原体是肺炎克雷伯菌、鲍曼不动杆菌和金黄色葡萄球菌。PCR 结果检测到 172 例中的 37 例（21.5%）携带 blaNDM 基因，30 例（17.4%）携带 blaVIM 基因；15 株（8.7%）分离株同时携带这两种基因。
blaNDM-1 和 blaVIM 基因是导致 VAP 对碳青霉烯类耐药的主要抗生素耐药基因，突出了具有潜在公共卫生和治疗挑战的 CRE 菌株。印度的诊断实验室必须高度警惕早期 MBL 的检测，因为它可能限制 MBL 基因的广泛传播。
