Group B Streptococcus Colonization, Antibiotic Susceptibility, and Serotype Distribution among Saudi Pregnant Women.

BACKGROUND: Group B Streptococcus (GBS) comprises the normal flora of the female urogenital tract and can be transferred to neonates during delivery, causing invasive diseases. This study was performed to investigate the colonization rate, antibiotic susceptibility, and serotype of GBS among Saudi pregnant women. MATERIALS AND METHODS: In this cross-sectional study, vagino-rectal swabs from 400 pregnant women were collected over a period of one year. Identification of GBS isolates and determination of their antibiotic susceptibility were performed using the Microscan Walk Away system. The isolates were then typed using both latex agglutination and capsular gene-based multiplex polymerase chain reaction assays. RESULTS: Sixty (15.0%) subjects were colonized by GBS, with serotype Ia as the dominant type (30.0%) followed by serotype III and V (25.0%, each). Only 43 (71.7%) isolates were typed by latex agglutination, whereas the remaining isolates were not typable or were non-specifically typed as compared to the genotyping assay, which revealed the specific type of each GBS isolate. The highest resistance rates were observed for erythromycin and clindamycin (16.7%, each), which were mainly restricted to the prevalent serotypes. CONCLUSION: This study is the first to report the distribution of GBS serotypes based on molecular genotyping in Saudi Arabia. GBS colonization was evident among pregnant women, and resistance to erythromycin and clindamycin was predominant among serotypes Ia, III, and V. Molecular genotyping using capsular gene-based multiplex PCR provided reliable typing of the investigated GBS isolates in terms of sensitivity and specificity as compared to conventional serotyping using latex agglutination.

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.

Activins and their related proteins in colon carcinogenesis: insights from early and advanced azoxymethane rat models of colon cancer.

BACKGROUND: Activin-A may exert pro- or anti-tumorigenic activities depending on cellular context. However, little is known about its role, or the other mature activin proteins, in colorectal carcinoma (CRC). This study measured the expression of activin ßA- & ßB-subunits, activin type IIA & IIB receptors, smads 2/3/4/6/7 and follistatin in CRC induced by azoxymethane (AOM) in rats. The results were compared with controls and disseminated according to the characteristics of histopathological lesions. METHODS: Eighty male Wistar rats were allocated into 20 controls and the remaining were equally divided between short 'S-AOM' (15 weeks) and long 'L-AOM' (35 weeks) groups following injecting AOM for 2 weeks. Subsequent to gross and histopathological examinations and digital image analysis, the expression of all molecules was measured by immunohistochemistry and quantitative RT-PCR. Activin-A, activin-B, activin-AB and follistatin were measured by ELISA in serum and colon tissue homogenates. RESULTS: Colonic pre-neoplastic and cancerous lesions were identified in both AOM groups and their numbers and sizes were significantly (P < 0.05) greater in the L-AOM group. All the molecules were expressed in normal colonic epithelial cells. There was a significantly (P < 0.05) greater expression of ßA-subunit, IIB receptor and follistatin in both pre-neoplastic and cancerous tissues. Oppositely, a significant (P < 0.05) decrease in the remaining molecules was detected in both AOM groups. Metastatic lesions were only observed within the L-AOM group and were associated with the most significant alterations of all molecules. Significantly higher concentrations of activin-A and follistatin and lower activin-AB were also detected in both groups of AOM. Tissue and serum concentrations of activin-A and follistatin correlated positively, while tissue activin-AB inversely, and significantly with the numbers and sizes of colonic lesions. CONCLUSIONS: Normal rat colon epithelial cells are capable of synthesising, controlling as well as responding to activins in a paracrine/autocrine manner. Colonic activin systems are pathologically altered during tumorigenesis and appear to be time and lesion-dependent. Activins could also be potential sensitive markers and/or molecular targets for the diagnosis and/or treatment of CRC. Further studies are required to illustrate the clinical value of activins and their related proteins in colon cancer.

Thymoquinone subdues tumor growth and potentiates the chemopreventive effect of 5-fluorouracil on the early stages of colorectal carcinogenesis in rats.

Colorectal cancer (CRC) is one of the most prevalent cancers and has a high mortality rate. Insensitivity and the limited therapeutic efficacy of its standard chemotherapeutic drug, 5-fluorouracil (5-FU), represents an important challenge in CRC treatment. The robust antitumor properties of thymoquinone (TQ), the main bioactive constituent of Nigella sativa, have recently been demonstrated on different cancers. We investigated whether TQ could potentiate the chemopreventive effect of 5-FU to eradicate the early stages of CRC and elucidated its underlying mechanisms. An intermediate-term (15 weeks) model of colorectal tumorigenesis was induced in male Wistar rats by azoxymethane (AOM), and the animals were randomly and equally divided into five groups: control, AOM, AOM/5-FU, AOM/TQ, and AOM/5-FU/TQ. TQ (35 mg/kg/d; 3 d/wk) was given during the seventh and 15th weeks post-AOM injection, while 5-FU was given during the ninth and tenth weeks (12 mg/kg/d for 4 days; then 6 mg/kg every other day for another four doses). At week 15, the resected colons were subjected to macroscopic, histopathological, molecular, and immunohistochemical examinations. Interestingly, 5-FU/TQ combination therapy resulted in a more significant reduction on AOM-induced colorectal tumors and large aberrant crypts foci than treatment with the individual drugs. Mechanistically, 5-FU and TQ remarkably cooperated to repress the expression of procancerous Wnt, ß-catenin, NF-κB, COX-2, iNOS, VEGF, and TBRAS and upregulate the expression of anti-tumorigenesis DKK-1, CDNK-1A, TGF-ß1, TGF-ßRII, Smad4, and GPx. Overall, our findings present the first report describing the in vivo enhancement effect of combined TQ and 5-FU against early stages of CRC; however, further studies are required to determine the value of this combination therapy in an advanced long-term model of CRC and also to realize its clinical potential.

Paricalcitol Enhances the Chemopreventive Efficacy of 5-Fluorouracil on an Intermediate-Term Model of Azoxymethane-Induced Colorectal Tumors in Rats.

Colorectal cancer is a common cancer with high mortality rate. Despite being the standard anti-colorectal cancer drug, 5-fluorouracil (5-FU) exhibits only limited therapeutic benefits. Herein, we investigated whether paricalcitol, a synthetic vitamin D analogue with potential antitumor properties, would enhance the chemopreventive efficacy of 5-FU on an intermediate-term (15 weeks) model of colorectal tumors induced by azoxymethane (AOM) in rats. After AOM injection, 5-FU was administered during the 9th and 10th weeks (12 mg/kg/day for 4 days, then 6 mg/kg every other day for another 4 doses), whereas paricalcitol (2.5 µg/kg/day; 3 days/week) was given from the 7th to the 15th week. At week 15, the animals were euthanized and their resected colons were examined macroscopically and microscopically. Quantitative RT-PCR was used to measure the transcription activities of Wnt, ß-catenin, DKK-1, CDNK-1A, NF-κB, and COX-2 genes, and ELISA was used to quantify the protein levels of ß-catenin, COX-2, HSP90, and VEGF. IHC was additionally used to measure ß-catenin, HSP90, and inducible nitric oxide synthase (iNOS). Compared with their individual therapy, combination of 5-FU and paricalcitol showed more significant reducing effect on numbers of grown tumors and large aberrant crypts foci. Mechanistically, paricalcitol and 5-FU had cooperated together to repress the expression of procancerous Wnt, ß-catenin, NF-κB, COX-2, iNOS, VEGF, and HSP-90 more, and to upregulate the expression of antitumorigenesis DKK-1 and CDNK-1A, compared with their monotherapies. Our findings suggest that combined use of paricalcitol with 5-FU exhibits an augmenting chemopreventive effect against colorectal tumors, and might potentially be useful for chemoprevention in colorectal cancer patients. Cancer Prev Res; 9(6); 491-501. ©2016 AACR.

Vitamin D3 enhances the tumouricidal effects of 5-Fluorouracil through multipathway mechanisms in azoxymethane rat model of colon cancer.

BACKGROUND: Vitamin D3 and its analogues have recently been shown to enhance the anti-tumour effects of 5- Fluorouracil (5-FU) both in vitro and in xenograft mouse model of colon cancer. This study measured the potential mechanism(s) by which vitamin D3 could synergise the tumouricidal activities of 5-FU in azoxymethane (AOM) rat model of colon cancer. METHODS: Seventy-five male Wistar rats were divided equally into 5 groups: Control, AOM, AOM-treated by 5-FU (5-FU), AOM-treated by vitamin D3 (VitD3), and AOM-treated by 5-FU + vitamin D3 (5-FU/D). The study duration was 15 weeks. AOM was injected subcutaneously for 2 weeks (15 mg/kg/week). 5-FU was injected intraperitoneally in the 9th and 10th weeks post AOM (8 total injections were given: 12 mg/kg/day for 4 successive days, then 6 mg/kg every other day for another 4 doses) and oral vitamin D3 (500 IU/rat/day; 3 days/week) was given from week 7 post AOM till the last week of the study. The colons were collected following euthanasia for gross and histopathological examination. The expression of ß-catenin, transforming growth factor-ß1 (TGF-ß1), TGF-ß type 2 receptor (TGF-ßR2), smad4, inducible nitric oxide synthase (iNOS), and heat shock protein-90 (HSP-90) proteins was measured by immunohistochemistry. In colonic tissue homogenates, quantitative RT-PCR was used to measure the mRNA expression of Wnt, ß-catenin, Dickkopf-1 (DKK-1) and cyclooxygenase-2 (COX-2) genes, while ELISA was used to measure the concentrations of TGF-ß1, HSP-90 and COX-2 proteins. RESULTS: Monotherapy with 5-FU or vitamin D3 significantly decreased the number of grown tumours induced by AOM (P < 0.05); however, their combination resulted in more significant tumouricidal effects (P < 0.05) compared with monotherapy groups. Mechanistically, vitamin D3/5-FU co-therapy significantly decreased the expression of Wnt, ß-catenin, iNOS, COX-2 and HSP-90 and significantly increased the expression of DKK-1, TGF-ß1, TGF-ßR2, smad4 (P < 0.05), in comparison with their corresponding monotherapy groups. CONCLUSIONS: Vitamin D3 and 5-FU synergise together and exhibit better anticancer effects by modulating Wnt/ß-catenin pathway, TGF-ß1 signals, iNOS, COX-2 and HSP-90. Further studies are required to illustrate the clinical value of vitamin D supplementation during the treatment of colon cancer with 5-FU in human patients.