Predominance and association risk of Blastocystis hominis subtype I in colorectal cancer: a case control study

Background

Blastocystis, a genetically diverse intestinal parasite with controversial pathogenic potential, has increasingly been incriminated for diarrheal illness in immunocompromised individuals including colorectal cancer (CRC) patients. The aim of the current study was to assess the possible association between Blastocystis infection and CRC condition in Makkah, Saudi Arabia (KSA).

Methods

Stool samples were collected from 80 non-cancer (NC) and 138 cancer subjects including 74 CRC patients and 64 patients with other cancers outside gastrointestinal tract (COGT). Molecularly confirmed Blastocystis isolates were genetically grouped and subtyped using multiplex polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP) and sequence-tagged site primers-based PCR (PCR-STS), respectively.

Results

Blastocystis hominis were confirmed in 29.7, 25 and 15% among CRC, COGT and NC patients, respectively. Obtained Blastocystis isolates were initially categorized into 2 groups (A and C), which were subsequently subtyped into 3 different subtypes; subtype-I (38%), subtype-II (44%) and subtype-V (22%). Interestingly, subtype-I was the most predominantly detected subtype (54.5%) among CRC patients with a significant association risk (COR 7.548; 95% CI: 1.629–34.987; P = 0.004).

Conclusion

To the best of our knowledge, the current study is the first to provide genetic insights on the prevalence of Blastocystis hominis among CRC patients in Makkah, KSA. Moreover, the study suggests for a possible association between subtype-I of Blastocystis hominis and CRC, which could indicate a potential influence of Blastocystis on CRC condition. Further studies are required to confirm this association risk and to investigate the possible underlying mechanism of postulated carcinogenic influence of Blastocystis hominis subtype-I.

Electronic supplementary material

The online version of this article (doi:10.1186/s13027-017-0131-z) contains supplementary material, which is available to authorized users.

Prevalence of intestinal parasites and bacteria among food handlers in a tertiary care hospital

Objectives:

The aim of this work is to determine the prevalence of intestinal parasites and bacteria among the food handlers.

Materials and Methods:

Two hundred food-handlers were subjected to a cross-sectional study working in the kitchen of a tertiary care hospital, i.e., Alnoor Specialist Hospital, Makkah, Saudi Arabia from February 2 to 27, 2009. The stool samples were examined for intestinal parasites following direct microscopic examination, formol ether concentration (Ritchie), and staining with modified acid fast staining techniques. For enteropathogenic bacteria samples were inoculated onto MacConkey's agar, deoxycholate citrate agar, xylose lysine deoxycholate agar as per the World Health Organization protocol. Fingernail materials were examined microscopically for enteropathogenic bacteria and parasites.

Results:

The majority (80%) of the food-handlers were young adults aged from 22 to 42 years. No intestinal parasites were detected from fingernail contents. Forty six (23%) stool specimens were positive for intestinal para¬sites. Giardia lamblia 18 (9%) was most frequent among the 10 different types of detected intestinal parasites followed by Entamoeba histolytica 9 (4.5%). No pathogenic bacteria were detected in all stool samples, whereas finger nails showed isolation of microorganisms as coagulase-negative staphylococci 79 (39.5%), followed by Staphylococcus aureus 35 (17.5%).

Conclusion:

The findings emphasized the importance of food handlers as potential sources of infections and suggested health institutions for appropriate hygienic and sanitary control measures.