Amoebiasis is one of the most important infectious diseases afflicting mainly tropical and subtropical countries. This study was carried out in the Sharjah Emirate, UAE in order to accurately detect and differentiate Entamoeba histolytica, Entamoeba dispar and E. moshkovskii in fecal samples collected from the Sharjah municipality public health clinic by ELISA and nested polymerase chain reaction (PCR). One hundred and twenty specimens were examined and the PCR was positive for E. histolytica, E. dispar and E. moshkovskii (collectively referred to as Entamoeba complex) in 19.2% (23 out of 120). Of those, 10% (12/120) were mono -infection with E. histolytica; 2.5% (3/120) with E. dispar; and 2.5% (3/120) E. moshkovskii. The nested PCR also detected mixed infections by both E. histolytica and E. dispar in 3.3% (4/120) and E. dispar and E. moshkovskii in 0.8% (1/120). The TechLab ELISA kit failed to detect E. histolytica in any of the E. histolytica PCR positive samples. Overall, the percentage of E. histolytica including those found in mixed infections was 13.3% (16/120). Compared to nested PCR, microscopy was found to have an overall sensitivity of 52.2% and a specificity of 75.2% for detection of Entamoeba complex. The present study indicates that E. histolytica is present in the UAE with an average incidence rate of 13.3%. However, larger studies need to be conducted in order to confirm these findings. We propose the use of PCR in both the routine diagnosis of amoebiasis and epidemiological survey in the UAE.
The objectives of the study were to assess the behavior of Escherichia coli O157:H7 during the manufacture of fruit yogurt at different fermentation and storage temperatures. Reconstituted milk was fermented at 37, 40 or 45C; the resultant product was stored at 4, 10 or 15C for 7 days. Samples of milk and yogurt were analyzed. E. coli O157:H7 and lactic acid bacteria (LAB) counts; pH of samples was recorded. During fermentation, E. coli O157:H7 grew in the presence or absence of LAB regardless of temperature. E. coli O157:H7 increased in presence of thermophilic LAB more than 2.75 log cfu/mL. The growth of LAB in all samples showed the same trend. The pH values of milk containing E. coli O157:H7 and LAB decreased gradually to reach 4.6 ± 0.1 at the end of fermentation period. During cooling, there was neither growth nor death of E. coli O157:H7 at 4 and 10C, while a slight increase at 15C. All the experiments showed significant differences in the population of E. coli O157:H7 in the presence or absence of LAB. During storage, E. coli O157:H7 number declined for all experiments and approached undetectable levels at the end of storage. The sensitivity of E. coli O157:H7 to acidity and lowered temperature was noticed during storage.
Practical Applications
Escherichia coli O157:H7 has emerged as a major foodborne pathogen and has been implicated in several outbreaks involving milk and dairy products. The results of the present study indicate that E. coli cannot tolerate the acidity and storage temperature. Applying quality control systems in the processing line will ensure that the E.coli will not survive in the commercially prepared fruit yogurt.
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