Original Articles
Copyright ©The Author(s) 1998. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 15, 1998; 4(3): 234-237
Published online Jun 15, 1998. doi: 10.3748/wjg.v4.i3.234
Detection of bacterial DNA from cholesterol gallstones by nested primers polymerase chain reaction
Xiao-Ting Wu, Lu-Jia Xiao, Xing-Quan Li, Jie-Shou Li
Xiao-Ting Wu, Jie-Shou Li, Research Institute of General Surgery, Nanjing General Hospital of PLA, Clinical School of Medical College, Nanjing University, Nanjing 210002, Jiangsu Province, China
Lu-Jia Xiao, Department of Hepatobiliary Surgery, First Clinical School of Medicine, West China University of Medical Sciences, Chengdu 610041, Sichuan Province, China
Xing-Quan Li, Department of Hemotology, Affiliated Hospiotal, Chinese Academy of Military Medical Sciences, Beijing 100039, China
Xiao-Ting Wu, male, born on January 31, 1957 in Chengdu, Sichuan Province, graduated from West China University of Medical Sciences as M.D. in 1996, post-doctorate of clinical medicine, associate professor of surgery specializing in hepatobiliary surgery, having 16 papers published. Presented at the 11th Biennial Congress, Asian Surgical Association, 2-5 March, 1997, Hong Kong and the 7th Chinese Biliary Surgery Congress, Xi’an, 10-13 April, 1997.
Author contributions: All authors contributed equally to the work.
Correspondence to: Dr. Xiao-Ting Wu, Research Institute of General Surgery, Nanjing General Hospital of PLA, Clinical School of Medical College, Nanjing University, Nanjing 210002, Jiangsu Province, China
Telephone: +86-25-4826808 ext 58064 Fax: +86-25-4803956
Received: March 1, 1998
Revised: April 20, 1998
Accepted: May 10, 1998
Published online: June 15, 1998

AIM: To search for bacterial DNA sequences in cholesterol gallstones with negative bacterial culture.

METHODS: DNA was extracted from cholesterol gallstones in gallbladders and nested primers polymerase chain reaction (NP-PCR) was used to amplify bacterial gene fragments for identifying the existence of bacteria. The samples of bacterial DNA extracted from potentially causative or unrelated living bacteria were amplified in vitro as the standard markers and comparative 16S ribosomal RNA sequence analysis was made for bacterial identification.

RESULTS: The gallbladder gallstones of 30 patients were analyzed and bacterial DNA was found in 26 patients. Among them, gallstones with cholesterol content between 30%-69% were seen in 5 (5/5) patients, 70%-90% in 11 (11/14) patients, and more than 90% in 10 (10/11) patients. There was no difference either in cholesterol and water content of gallstones or in harboring bacterial DNA of gallstones. E. coli-related DNA fragments appeared in the stones of 8 (26.67%) patients; propionibacteria type DNA in 7 (23.33%); and harbored bacterial gene fragments in 2 patients, similar to Streptococcus pyogenes. A more heterogenous sequence collection was found in 7 (23.33%) patients, which could belong to multiple bacterial infections. Two (6.67%) patients had bacterial DNA with low molecular weight which might be related to some unidentified bacteria.

CONCLUSION: Most cholesterol gallstones harbor bacterial DNA. It is important to determine whether these microorganisms are innocent bystanders or active participants in cholesterol gallstone formation.

Keywords: cholelithiasis/microbiology, propionibacterium acnes, staphylococcus aureus, DNA, bacterial, polymerase chain reaction