Israel Medical Association Journal

Background: Serology of amebiasis is affected by low sensitivity and specificity.

Objectives: To evaluate the advantage of the indirect hemagglutination assay and enzyme-linked immunosorbent assay in the diagnosis of amebiasis, using Entamoeba histolytica soluble antigen (macerated amebic antigens) prepared from four different virulent isolates, continuously cultivated in the presence of the original enteric bacteria.

Methods: Using IHA[1] and ELISA[2] with MAA[3] antigen we examined 147 sera samples from patients with gastrointestinal symptoms, and 11 sera from amebiasis cases (confirmed by microscopy and copro-antigen ELISA ).

Results: Of 104 of the 147 (70.7%) symptomatic cases that were amebiasis positive by IHA, 81 (55.1%) were positive by MAA-ELISA. In addition, of 11 amebiasis cases confirmed by microscopy and copro-antigen ELISA , 7 (64%) were amebiasis positive by both tests. Four species of bacteria were isolated from the ameba cultures: Escherichia coli, Morganella morganii, Proteus mirabilis, and Streptococcus lactis. Elimination of the bacteria from the cultures by an antibiotics cocktail containing gentamicin, imipenem, piperacillin-tazobactam and vancomycin was the preferred method. Absorption of patients' sera to bacterial antigen prior to serological analysis had only a marginal effect.

Conclusions: These results indicate a correlation of 61% between the ELISA developed in this study and the IHA tests in the diagnosis of amebiasis.

Background: Transmission of Pseudomonas aeruginosa among cystic fibrosis patients attending health camps has been reported previously.

Objectives: To determine the transmission of P. aeruginosa among CF[1] patients during three winter camps in the Dead Sea region in southern Israel.

Methods: Three consecutive CF patient groups were studied, each of which spent 3 weeks at the camp. The patients were segragated prior to camp attendance: patients who were not colonized with P. aeruginosa constituted the first group and colonized patients made up the two additional groups. Sputum cultures were obtained upon arrival, at mid-camp and on the last day. Environmental cultures were also obtained. Patients were separated during social activities and were requested to avoid social mingling. Isolates were analyzed by antibiotics susceptibility profile and by pulsed field gel electrophoresis.

Results: Ninety isolates from 19 patients produced 28 different fingerprint patterns by PFGE[2]. Isolates from two siblings and two patients from the same clinic displayed the same fingerprint pattern. These patients were already colonized with these organisms upon arrival. Two couples were formed during the camp, but PFGE showed no transmission of organisms. All other patients' isolates displayed unique fingerprint patterns and were distinguishable from those of other attendees, and none of the P. aeruginosa-negative patients acquired P. aeruginosa during camp attendance. Environmental cultures were negative for P. aeruginosa.

Conclusions: We were unable to demonstrate cross-infection of P. aeruginosa among CF patients participating in health camps at the Dead Sea who were meticulously segregated.