No abstract

Blastocystis is a single-celled intestinal parasite commonly found in humans and a broad range of animals all over the world. In humans, its role in health and disease remains unsettled. The aim of our study was to investigate the distribution of Blastocystis and Blastocystis subtypes (ST) in patients with inflammatory bowel disease (IBD) and control subjects. A total of 71 stool samples were collected from IBD patients, 69 and 2 of whom had ulcerative colitis (UC) and Crohn's Disease (CD), respectively. Moreover, 166 stool samples from healthy subjects were included as control samples. All stool samples were cultivated, and 550-bp fragments of the small subunit ribosomal RNA gene was amplified from Blastocystis-positive cultures. All PCR-positive samples were sequenced. Blastocystis was observed in 9 (12.67%) and 35 (21.1%) IBD patients and healthy controls, respectively. There was no statistically significant correlation between IBD and presence of Blastocystis (P = 0.147). There was a statistically significant correlation between age and Blastocystis colonization in the IBD group (P < 0.05), but not among healthy controls. No significant correlation between gender and colonization was observed. ST1 and ST3 were obtained from 1 (12.5%) and 7 (87.5%) IBD patients, respectively, while in the healthy control group, subtypes 1, 2, and 3 were found in 14 (40%), 12 (34.28%), and 9 (25.72%), respectively. Phylogenetic analysis showed no variation in the distribution of subtypes nor intra-subtype genetic diversity between samples acquired from IBD patients and healthy controls. This study showed a trend towards a lower prevalence of Blastocystis in IBD patients than in control subjects. ST3 sequences isolated from IBD patients and control individuals did not appear to differ genetically.

Mixed infections and heteroresistance of Helicobacter pylori contribute to decreased efficacy of treatments. This study aimed to investigate frequency of clarithromycin heteroresistance and its link with mixed infections, medication history, and disease severity. A total of 40 pairs of H. pylori strains were isolated from the antrum and corpus of 97 patients. Susceptibility of the strains to clarithromycin was measured by agar dilution method. Site-specific mutations of 23S rRNA at A2143G, A2142G, and A2142C positions were analyzed by PCR and genomic relatedness of pairs of the strains was determined by random amplified polymorphic DNA (RAPD)-PCR. The results showed a prevalence of 35% (14/40) clarithromycin resistance. Diversity of the antrum and corpus isolates in resistance to clarithromycin was detected among 17.5% (7/40) of the patients. Similarly, diversity in MIC value was also detected in two patients infected with the sensitive strains. Significant difference in frequency of resistance was detected among patients with peptic ulcer disease (PUD) (MIC90 32 μg/mL) and severe gastritis (MIC90 16 μg/mL), compared with those who suffered from non-ulcer dyspepsia (NUD) (MIC90 8 μg/mL) and chronic gastritis (MIC90 0.25 μg/mL). MIC values showed 8-32 folds increased levels in the corpus. A2142G, A2143G, and A2142C mutations were detected in three, two, and two patients, respectively, but not observed in 46% of the resistant strains. RAPD-PCR fingerprints showed identical molecular patterns for the isolates of the corpus and antrum in each patient. In conclusion, microevolution of H. pylori strains during chronic infection, rather than mixed infection, and inappropriate medication appear to be main reasons of treatment failure in adults.

Microsporida are known as opportunistic unicellular organisms and have recently been reclassified as fungi that have been frequently reported from patients with congenital and acquired immunity failure disorders, worldwide. However, use of immunosuppressive medications in inflammatory bowel disease (IBD) patients significantly decreases overall immunity, and increases their susceptibility to opportunistic infections. Totally, 71 stool samples were collected from IBD patients consisted of 69 ulcerative colitis (UC) patients and two Crohn's disease (CD) patients. All patients had taken immunosuppressive and/or immunomodulator drugs for at least 3 weeks. DNA was extracted from all stool samples and Nested PCR was performed using genus-specific primers based on small subunit ribosomal RNA (SSU rRNA) gene. Fisher's Exact Test was applied to evaluate statistical association between microsporidia infection and sex, age and types of IBD. Mean of age ± s.d., women and men percentage of the attended patients were 36·17 ± 11·93, 60·6%, and 39·4%, respectively. A 440-bp fragment of SSU rRNA gene attributed to Enterocytozoon bieneusi was amplified from 12·7% of IBD patients. No Encephalitozoon DNA was detected in the samples. No microsporidia-positive sample was found in CD patients. Fisher's Exact Test showed that there was no statistically significant correlation between intestinal microsporidiosis and age, sex, and IBD types with P values: 0·389, 1·00, and 1·00, respectively. This study has shown IBD patients undergoing immunosuppressive/immunomodulators medications, which may be susceptible to intestinal microsporida infection. E. bieneusi is the commonest intestinal microsporidan reported from IBD patients.

Background: Detection of the cause of diarrhoeal diseases is important for the management of the outbreaks. Aims: This study investigated the prevalence of Shiga toxin-producing bacteria in stool samples of patients with diarrhoea associated with outbreaks of foodborne illness in the Islamic Republic of Iran. Methods: A total of 532 stool and rectal swab samples from 70 sporadic outbreaks during May 2014 to August 2015 were examined for infection with Shiga toxin-producing bacteria. The isolates were examined for carriage of the virulence genes stx 1 and stx 2 in all isolates and eae/ehxA in Escherichia coli.Results: E. coli, Shigella spp., Citrobacter spp., Enterobacter spp., Klebsiella spp. and other enteric bacteria were detected in 77.7% (376/484), 5.0% (24/484), 3.9% (19/484), 0.4% (2/484), 3.7% (18/484) and 9.3% (45/484) of the samples respectively. Of the 196 sorbitol-negative E. coli strains, 3 (1.5%) carried the stx 1 gene as did 2 of the 19 (10.5%) Citrobacter strains. Conclusion: Shiga toxin-producing Citrobacter spp. strains should be considered as a newly emerging foodborne pathogen in outbreaks.