Species distribution and Candida albicans genotyping of invasive pulmonary fungal infection in ICU patients

Abstract

Objective To understand the species distribution of IPFI, drug sensitivity, and RAPD- PCR fingerprint characteristics of Candida albicans in different ICU patients in Meizhou, and the differences in drug resistance between different genotype strains.

Methods Totally 149 ICU patients with IPFI during their stays were included in the study conducted, specimens were identified by strain analysis and drug susceptibility testing using Mérieux VITEK 2-Compact and API identification system, and 62 isolates of Candida albicans were analyzed by RAPD technique.

Results The results showed that IPFI species in the region accounted for 38.51% (62/161) of Candida albicans, followed by Candida tropicalis, Candida parapsilosis, Candida glabrata, Candida krusei, and Candida guilliermondii. Candida non- albicans, the overall proportion of Candida non- albicans was 48.45% (78/161); they had good sensitivity to commonly used antifungal drugs, but there were resistant strains of Candida parapsilosis to caspofungin and the relatively low sensitivity of Candida glabrata to azoles; the number of amplified bands of Candida albicans P2 random primers was 1 to 5, and the band size was between 300 bp and 1.8 kb. The main bands were mainly 300 bp, 400 bp and 600 bp. Cluster analysis was used. These strains were divided into four gene clusters, A to D, including 11 A gene clusters, 42 B gene clusters, 7 C gene clusters and 2 D gene clusters. The difference in sensitivity of different genotypes of Candida albicans to each drug was not significant.

Conclusion This indicates that Candida albicans, Candida tropicalis and Candida parapsilosis were the most common pathogens of IPFI in ICU patients in Meizhou, Guangdong. Candida albicans was rich in gene polymorphisms, RAPD technology for Candida albicans genotypes, identification is of great significance.

Abstract

摘要： 目的 旨在了解梅州地区ICU患者侵袭性肺部真菌感染 (IPFI) 的物种分布、药物敏感及白色念珠菌RAPDPCR 指纹图谱特征和不同基因型菌株耐药性差异。 方法 收集ICU中149例IPFI患者的呼吸道标本, 采用法国梅里埃 VITEK 2-Compact和API鉴定系统进行菌株鉴定和药敏试验, 运用RAPD 技术对分离的62 株白色念珠菌进行分析。 结果 该地区IPFI的物种以白色念珠菌占比最高为38.51% (62/161), 其次为热带念珠菌、近平滑念珠菌、光滑念珠菌、 克柔念珠菌和季也蒙念珠菌等非白念珠菌, 非白念珠菌整体占比为48.45% (78/161) ; 它们对常用抗真菌药物具有较好 的敏感性, 但是出现了近平滑念珠菌对卡泊芬净的耐药菌株和光滑念珠菌对唑类药物敏感性相对较低的情况; 白色念 珠菌P2 随机引物扩增条带数量1~5条, 条带大小在300 bp~1.8 kb, 以300 bp、400 bp 和600 bp 3 个主条带为主; 利用聚 类分析将这些菌株分为A~D 4个基因群, 其中A基因群11株, B基因群42株, C基因群7株和D基因群2株; 不同基因型 白色念珠菌对各药物敏感性的差异无统计学意义。 结论 白色念珠菌、热带念珠菌和近平滑念珠菌等念珠菌属是广 东梅州地区ICU患者IPFI的最常见病原体, 白色念珠菌存在丰富的基因多态性, RAPD 技术对于白色念珠菌的基因型 鉴定具有重要意义。