环境pH值对钉螺体内可培养微生物影响的实验研究

doi:10.20199/j.issn.1672-2302.2025.05.007

摘要/Abstract

摘要：

目的了解钉螺体内可培养微生物群落结构特征，探讨环境pH值对钉螺体内可培养微生物的影响，为微生物灭螺提供参考。方法野外采集钉螺，选择阴性成螺并随机分为中性组（A1组、A2组）、酸性组（B1组、B2组）、碱性组（C1组、C2组）和野外组（Y组），每组10只。A1组、B1组、C1组钉螺分别用去氯水（pH=7）、酸性培养液（pH=4）、碱性培养液（pH=10）饲养1周；A2组、B2组、C2组按上述条件饲养2周；Y组钉螺直接进行解剖。取钉螺软体组织制备菌悬液，分离培养需氧菌和真菌并进行菌落计数，运用Biolog微生物鉴定系统并结合显微镜染色观察鉴定微生物种类。结果野外组（Y组）、中性组（A1组、A2组）、酸性组（B1组、B2组）、碱性组（C1组、C2组）共7组钉螺体内可培养菌落总数分别为（6.106±0.854）、（6.520±0.365）、（7.002±0.627）、（7.434±0.400）、（6.928±0.294）、（7.233±0.564）、（7.527±0.693）lg CFU/g，培养1周的碱性组（C1组）和酸性组（B1组）菌落总数高于中性组（A1组），培养2周的碱性组（C2组）的菌落总数高于中性组（A2组）和酸性组（B2组）（P均<0.05）。钉螺体内可培养的需氧菌共分离出7种，以小麦拉氏杆菌、水生黄杆菌和栖冷克吕沃尔菌为优势菌种；真菌共分离出14种，以新生隐球菌B、Trigonosporomyces hylophilus和白吉利丝孢酵母A为优势菌种。结论从野外环境到实验室饲养环境，钉螺体内可培养的菌群结构会发生相应变化。碱性环境可以提高钉螺体内可培养需氧菌的多样性，但其对钉螺存活的生态学意义仍有待进一步阐明。

关键词: 血吸虫病, 钉螺, 微生物, pH值

Abstract:

Objective To characterize the structure of the culturable microbial communities in Oncomelania hupensis(O. hupensis), and investigate the effects of environmental pH on the microorganisms cultured from O. hupensis for a reference in microbial control of this snail species. Methods The field-collected negative O. hupensis were randomized to neutral groups (A1, A2), acidic groups (B1, B2), alkaline groups (C1, C2), and a field group (Y) (n=10 in each group). Snails in groups A1, B1, and C1 were maintained in dechlorinated water (pH=7), acidic culture medium (pH=4), and alkaline culture medium (pH=10), respectively, for one week, and those in groups A2, B2, and C2 were treated with the same protocol for two weeks. Snails in group Y were directly dissected upon sampling. The soft snail tissues were collected and used to prepare bacterial suspensions, which were continued for the culture and isolation of aerobic bacteria and fungi, and the total number of bacterial colonies was counted. The Biolog microbial identification system, together with microscopic staining observation, was used to identify the types of microorganisms. Results The total cultivable colony counts within O. hupensis from the field group (Y), neutral groups (A1, A2), acidic groups (B1, B2), and alkaline groups (C1, C2) were (6.106±0.854), (6.520±0.365), (7.002±0.627), (7.434±0.400), (6.928±0.294), (7.233±0.564), and (7.527±0.693) lg CFU/g, respectively. The total colony counts of the alkaline group (C1) and acidic group (B1) cultured for 1 week were higher than those of the neutral group (A1), and the total colony count was higher in alkaline group (C2) than that in neutral group (A2) and acidic group (B2) after being cultured for 2 weeks (all P<0.05). Seven aerobic bacterial species were isolated from O.hupensis, with Rathayibacter tritici, Flavobacterium hydatis, and Kluyvera cryocrescens as dominant strains. Fourteen fungal species were isolated, with Cryptococcus neoformans B, Trigonosporomyces hylophilus, and Trichosporon beigelii A as dominant strains. Conclusion The structure of the culturable microbiota in the O. hupensis undergoes corresponding change from the field habitat to the laboratory-rearing setting. Alkaline condition may enhance the diversity of cultivable aerobic bacteria in the snails, yet ecological significance of environment for O. hupensis survival remains to be further elucidated.

Key words: Schistosomiasis, Oncomelania hupensis, Microorganisms, pH value

中图分类号:

R532.21

龙萍, 徐宁, 黄君慧, 王嘉敏, 朱李芸, 周雨, 公衍峰, 姜庆五, 周艺彪. 环境pH值对钉螺体内可培养微生物影响的实验研究[J]. 热带病与寄生虫学, 2025, 23(5): 289-295.

LONG Ping, XU Ning, HUANG Junhui, WANG Jiamin, ZHU Liyun, ZHOU Yu, GONG Yanfeng, JIANG Qingwu, ZHOU Yibiao. Experimental study on the impact of environmental pH on culturable microorganisms in Oncomelania hupensis[J]. Journal of Tropical Diseases and Parasitology, 2025, 23(5): 289-295.

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组别	X1	X2	X3	X4	X5	X6	X7	合计
Y	486	37	48	150	36	0	0	757
A1	120	3	1 755	812	21	0	0	2 711
B1	832	14	1 457	446	20	0	0	2 769
C1	98	0	1 766	1 019	18	0	0	2 901
A2	83	15	590	1 764	10	10	0	2 472
B2	72	100	661	1 207	14	71	0	2 125
C2	81	4	934	1 684	7	0	29	2 739