ELSEVIER EUROPEAN JOURNAL OF INTERNAL MEDICINE European Journal of Internal Medicine 14 (2003) 367-371 www.elsevier.com/locate/ejim Original article The usefulness of PCR amplification of the IS61 10 insertion element of M. tuberculosis complex in ascitic fluid of patients with peritoneal tuberculosis Dimitrios Tzoanopoulos”, Konstantinos Mimidis, Stavros Giaglis, Konstantinos Ritis, Georgios Kartalis First Division of Internal Medicine, Democritus Universio of Thrace, Regional Hospital of Alexandroupolis, Alexandroupolis. Greece Received 11 December 2002; accepted 19 June 2003 Abstract Background: The diagnosis of tuberculous peritonitis (TP) may be difficult and elusive. The present study was designed to demonstrate the diagnostic usefulness of a nested polymerase chain reaction (PCR) assay, specific for the IS61 20 insertion element of M. tuberculosis complex, in patients with ascites who were suspected of having TP in order to achieve a more timely diagnosis and treatment. Methods: Three HIV-negative patients suffering from fever and ascites were evaluated for suspected TP. Specimens were obtained from ascitic fluid, bone marrow, and peripheral blood and analyzed by both conventional methods and nested PCR for the presence of bacilli. Response to antituberculous treatment was considered as the final criterion for diagnosis of peritoneal tuberculosis. Results: All three patients had an excellent response to antituberculous therapy. Our PCR-based protocol detected M. tuberculosis complex DNA in the ascitic fluid of all patients, whereas conventional methods failed to establish the disease. Furthermore, in one patient, M. tuberculosis was also detected in both bone marrow and peripheral blood. Conclusions: PCR amplification of the IS6110 sequence of M. tuberculosis complex in ascitic fluid is a useful tool when peritoneal tuberculosis is suspected. However, its validity still needs to be established. 0 2003 Elsevier B.V. All rights reserved. Keywords: Tuberculous peritonitis: PCR; IS61 10 insertion element 1. Introduction Tuberculous peritonitis (TP) is a form of abdominal tuberculosis that can involve the omentum, intestinal tract, liver, spleen, or female genital tract in addition to the parietal and visceral peritoneum [l]. It accounts for about l-2% of all cases of tuberculosis, the incidence having increased after the onset of the HIV epidemic [ 11. Clinically, TP is characterized by fever, abdominal pain, anorexia, weight loss, and ascites. However, none of these symptoms is specific for the disease, so it is commonly *Corresponding author. Ellis Alexiou 2, 55337 Triandria, Thessaloniki, Greece. Tel.: +30-23 I o-952-049; fax: +30-255 10-303-24. E-mail address: tzoanop@otenet.gr (D. Tzoanopoulos). misdiagnosed, especially as carcinomatous peritonitis in the elderly. Early diagnosis of TP is of major importance in the control of the disease [2,3]. Laparoscopy with direct biopsy is an excellent diagnostic method and must be considered for every patient with unexplained ascites [4]. A definitive diagnosis requires identification of bacilli in ascitic fluid or peritoneum tissue. However, acid-fast staining is usually negative and cultures are positive in 30-40% of cases, making bacteriological confirmation of the disease very difficult [l]. In recent years, advances in molecular techniques have provided a new approach to the rapid diagnosis of tuber- culosis by nucleic acid probes and polymerase chain reaction (PCR) [5,6]. The insertion sequence IS6110 has been successfully used as a target for PCR amplification in 0953-6205/03/$ - see front matter 0 2003 Elsevier B.V. All rights reserved doi:lO.l016/S0953-6205(03)0111-0