Validation and utilization of PCR for differential diagnosis and prevalence determination of Entamoeba histolytica/Entamoeba dispar in Salvador City, Brazil

Abstract

The absence of amplification of these samples indicates the presence of PCR inhibitors in the stool samples or the presence of DNA from Entamoeba species other than E. dispar, E. histolytica or E. hartmanni.

A Cross-Sectional Study ofEntamoeba histolytica/dispar/moshkovskiiComplex in Salvador, Bahia, Brazil

“…The PCR technique presented a sensitivity of 80% and specificity of 100%. Our data are in agreement with our previous report [17], in which we found a sensitivity value of 86.6%. In fact, 18 DNA samples did not amplify even after successive dilutions.…”

“…This finding suggested a significant reduction in the number of cases compared to previous studies performed by our group. In fact, we demonstrated, in 2010, prevalence rates of 3.2% and 5.0% in samples from private and public clinical laboratories, respectively [16, 17]. This decrease could be explained in part by the positive impact of government programs, which have improved sanitation infrastructure, thus reducing the occurrence of intestinal parasites among residents of the Salvador Metropolitan Area [20].…”

“…Furthermore, the recent expansion of health education and health care services also may have contributed to the early identification of E. histolytica new cases and prompt treatment. Additionally, it appears that E. histolytica is more common in North and rare in other regions, including Salvador [17, 21, 22].…”

“…dispar complex was analysed by PCR and no DNA amplified for E. histolytica . DNA amplified for E. dispar was observed in 86.6% of samples (227/262) [17]. However, in a previous study also conducted by our group, 4.6% (7/153) of hospitalized diarrheal children from Salvador tested positive for specific lectin of E. histolytica -Gal/GalNAc [18].…”

A historical review of the techniques of recovery of parasites for their detection in human stools

“…Biotechnology techniques are essential tools in certain situations 49,50 ; however, the use of molecular or immunological methods to detect parasites in fecal samples may not meet the economic and operational requirements of a laboratory, especially in regions with limited resources 17,25,26,[50][51][52] . Large reference centers can adopt these more sophisticated methods for research and differentiation between morphologically similar species 49,51 .…”