Studies of Plasmodium sporozoites and liver stages require dissection of Anopheles mosquitoes to obtain sporozoites for experiments. Sporozoites from the rodent parasite P. yoelii are routinely used to infect hepatocytes for liver stage culture, but sometimes these cultures become contaminated. Using standard microbiological techniques, a single colony type of Gram-negative rod-shaped bacteria was isolated from contaminated cultures. Mass spectrometry and sequencing of the bacterial 16S ribosomal RNA gene identified the contaminant as Elizabethkingia spp. Based on sequence comparison and published studies of the Anopheles microbiome, the best match was E. anophelis. Culture contamination was not ameliorated by density gradient purification of sporozoites. However, the addition of vancomycin to the culture media consistently reduced contamination and improved culture outcomes as measured by liver stage parasite size. Thus, mosquito salivary gland-derived E. anophelis is identified a potential contaminant of Plasmodium liver stage cultures that can be mitigated by the addition of antibiotics.

研究疟原虫子孢子和肝阶段需要的解剖按蚊的蚊子获得孢子进行实验。来自啮齿动物寄生虫约氏疟原虫的子孢子通常用于感染肝细胞用于肝阶段培养，但有时这些培养物被污染。使用标准的微生物学技术，从受污染的培养物中分离出单个菌落类型的革兰氏阴性棒状细菌。细菌的16S核糖体RNA基因的质谱和测序结果确定该污染物为伊丽莎白女王氏菌。基于序列比较和按蚊微生物组的已发表研究，最佳匹配是按蚊E. anophelis。子孢子的密度梯度纯化不能改善培养物的污染。但是，将万古霉素添加到培养基中可以持续减少污染，并通过肝阶段寄生虫大小来衡量培养效果。因此，蚊唾液腺来源的按蚊被鉴定为疟原虫肝阶段培养物的潜在污染物，可以通过添加抗生素来减轻。