CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES ›› 2023, Vol. 41 ›› Issue (2): 202-208.doi: 10.12140/j.issn.1000-7423.2023.02.012

• ORIGINAL ARTICLES • Previous Articles     Next Articles

Molecular identification and genetic characterization of Cryptosporidium spp. in patients with diarrhea in Ningbo City

QIN Yuan1(), LIU Hua1, JIANG Yanyan1, CAO Jianping1,2, SHEN Yujuan1,2,*()   

  1. 1 National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); NHC Key Laboratory of Parasite and Vector Biology; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai 200025, China
    2 School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
  • Received:2023-01-09 Revised:2023-02-28 Online:2023-04-20 Published:2023-04-20
  • Contact: SHEN Yujuan E-mail:qy_1226@163.com;shenyj@nipd.chinacdc.cn
  • Supported by:
    Support by the National Natural Science Foundation of China(82072307);Support by the National Natural Science Foundation of China(81772224);National Science and Technology Major Program of China(2018ZX10713001-004)

Abstract: Objective To analyze the Cryptosporidium infection and genetic characterization of outpatients with diarrhea in a sentinel hospital in Ningbo, to provide new ideas for clinical investigation on etiology of diarrhea. Methods A total of 650 fecal samples were collected from clinical diarrhea patients in NingBo City from November 2019 to July 2021. The genomic DNA from these samples was extracted, and the small subunit ribosomal ribonucleic acid gene (SSU rRNA) of Cryptosporidium was amplified by nested PCR. The products were analyzed by 1.5% agarose gel electrophoresis. The DNA from above positive sample was used as the template to amplify the 60-kDa glycoprotein (gp60) gene by nested PCR, of which the product was analyzed by 1.5% agarose gel electrophoresis. PCR amplification products of similar size to the target bands were sequenced in both directions, and blasted to identify the species or genotype according to the GenBank public database resources using Clustalx 2.1 software. Use Mega 11.0 software to draw the phylogenetic tree by the neighbour-joining (N-J) method. Results Among the fecal samples collected, 369 (56.8%) were from male diarrhea cases, and 281 (43.2%) female cases; of them the ages ranged from 1 to 99 years. After amplifying of the SSU rRNA gene, only one DNA sample showed specific bands at around 830 bp in electrophoresis, indicating Cryptosporidium spp. positive. The patient was a 53-year-old male, farmer with watery stool. According to the analysis of DNA sequence, it was identified as C. meleagridis, which has 100% homology with those of a human-derived isolate from Shanghai, a dairy-derived isolate from Heilongjiang Province, a chicken-derived isolate from Yunnan Province. The phylogenetic tree showed that these isolates locate in the same branch. The product of gp60 gene amplification displayed a specific band at around 955 bp, which was identified as the Ⅲb subtype family, with the highest homology (99.8%) to the human derived ⅢbA24G1R1 subtype, sequence alignment indicate it is a new subtype ⅢbA26G1 of C. meleagridis (GenBank accession No. OQ032548). Conclusion Zoonotic C. meleagridis was identified from a clinical diarrhea case in Ningbo area, suggesting that surveillance on Cryptosporidium infection in people with diarrhea and epidemiological tracing for infection source should be strengthened.

Key words: Clinical diarrhea patient, Cryptosporidium spp., C. meleagridis, Subtype

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