[Study on genetic approach in the detection of Cryptosporidium parvum and Giardia lamblia in acquired immunodeficiency syndrome patients].
OBJECTIVE
To establish genetic method in detecting Cryptosporidium parvum and Giardia lamblia which often coinfected with AIDS patients.


METHODS
Cryptosporidium oocysts and Giardia cysts were isolated and purified from fecal samples of the individuals infected with C. parvum and G. lamblia, respectively. Genomic DNAs were extracted. Two pairs of specific primers were designed or synthesized according to the 18S rRNA gene from C. parvum or the triose phosphate isomerase (tim ) gene from G. lamblia. Polymerase chain reaction(PCR) technique was used to amplify the DNA samples from the oocysts and the cysts, and those from the 6 control samples, including Schitosoma japonicum, Toxoplasma gondii , Entamoeba histolytica, Trichinella spiralis, Trichomonas vaginalis and human blood cells. DNA samples from 30 fecal samples of AIDS patients were detected with the same method.


RESULTS
One fragment of 500 bp was amplified with the primer of C. parvum, and the other one of 683 bp was amplified with the primer of G. lamblia. Twenty pg and 0.4 pg DNA of C. parvum and G. lamblia could be detected separately. The specificity of these two pairs of PCR primers was confirmed by the failure in the amplification of the control DNA samples. Out of 30 cases of AIDS patients, 7 showed C. parvum positive, while non Giardia was detected.


CONCLUSIONS
Genetic detection method for C. parvum and G. lamblia detection was established which was more sensitive and specific.
Lu
Si-qi
SQ
Department of Parasitology, Capital University of Medical Scienses, Beijing 100069, China.
Wang
Feng-yun
FY
Zhang
Ke
K
Xu
Lian-zhi
LZ
D000163:Acquired Immunodeficiency Syndrome / Q000382:microbiology*; D003457:Cryptosporidiosis / Q000175:diagnosis; D016785:Cryptosporidium parvum / Q000235:genetics*; D004269:DNA, Bacterial; D016829:Giardia lamblia / Q000235:genetics*; D005873:Giardiasis / Q000175:diagnosis; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
D004269:DNA, Bacterial