ICU患者呼吸机相关性肺炎病原菌分布及其与TLR4通路基因多态性的关联

Distribution of pathogens isolated from ICU patients with ventilator-associated pneumonia and its association with TLR4 pathway gene polymorphisms

目的 探究重症监护病房(ICU)患者呼吸机相关性肺炎(VAP)病原菌分布及其与Toll样受体4(TLR4)通路基因多态性的关联。方法 选取2019年10月-2021年10月井冈山大学附属医院ICU收治的101例机械通气继发VAP患者为感染组,随机选取同期医院ICU收治的101例机械通气未继发VAP患者为未感染组。采用聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)技术检测两组患者外周血TLR4通路关键基因多态性,包括TLR4、核因子-κB(NF-κB)、肿瘤坏死因子-α(TNF-α)、肿瘤坏死因子受体1(TNFR1)。结果 感染组患者痰液样本共分离112株病原菌,革兰阴性菌占74.11%、革兰阳性菌占9.82%、真菌占16.07%,其中铜绿假单胞菌占比最高;感染组患者IL-1β、IL-6、TNF-α水平高于未感染组(P<0.05);感染组携带TLR4+896 G/G基因、NF-κB p50 D/D基因、TNFRSF1A-609 G/G基因比例高于未感染组(P<0.05),感染组TLR4+896基因G等位基因、NF-κB p50基因D等位基因、TNFRSF1A-609基因G等位基因频率均高于未感染组(P<0.05);ICU机械通气患者中TLR4+896 G等位基因、NF-κB p50 D等位基因、TNFRSF1A-609 G等位基因携带者的IL-1β、IL-6、TNF-α水平高于未携带者(P<0.05)。结论 ICU患者VAP感染以革兰阴性菌为主,TLR4通路基因多态性与VAP密切相关,携带TLR4+896基因G等位基因、NF-κB p50基因D等位基因、TNFRSF1A-609基因G等位基因可增加ICU患者VAP的易感性。

OBJECTIVE To explore the distribution of pathogens isolated from intensive care unit(ICU) patients with ventilator-associated pneumonia(VAP) and analyze its association with Toll-like receptor 4(TLR4) pathway gene polymorphisms. METHODS A total of 101 mechanical ventilation patients with secondary VAP who were treated in ICU of Affiliated Hospital of Jinggangshan University from Oct 2019 to Oct 2021 were assigned as the infection group, meanwhile, 101 ICU patients who underwent mechanical ventilation but did not have secondary VAP were chosen as the no infection group. The polymorphisms of peripheral blood TLR4 pathway key genes, including TLR4, nuclear factor-κB(NF-κB), tumor necrosis factor-α(TNF-α) and tumor necrosis factor receptor 1(TNFR1), were detected by means of polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) technique. RESULTS Totally 112 strains of pathogens were isolated from sputum specimens of the patients in the infection group, 74.11% of which were gram-negative bacteria, 9.82% were gram-positive bacteria, and 16.07% were fungi;Pseudomonas aeruginosa was the predominant species. The levels of IL-1β, IL-6 and TNF-α of the infection group were higher than those of the no infection group(P<0.05). The proportions of patients carrying with TLR4+896 G/G gene, NF-κB p50 D/D gene, TNFRSF1A-609 G/G gene were higher in the infection group than in the no infection group(P<0.05). The frequencies of TLR4+896 gene G allele, NF-κB p50 gene D allele and TNFRSF1A-609 gene G allele of the infection group were higher than those of the no infection group(P<0.05). Among the ICU patients who underwent mechanical ventilation, the levels of IL-1β, IL-6 and TNF-α of the patients carrying with TLR4+896 G allele, NF-κB p50 D allele, and TNFRSF1A-609 G allele were higher than those of the patients who did not carried with those alleles(P<0.05). CONCLUSION The gram-negative bacteria are dominant among the pathogens isolated from the ICU patients with VAP. The TLR4 gene polymorphism is closely associated with VAP. The TLR4+896 gene G allele, NF-κB p50 gene D allele and TNFRSF1A-609 gene G allele may increase the susceptibility to VAP in the ICU patients.