Josias Rodrigues

High prevalence of aggregative adherent Escherichia coli strains in the mucosa-associated microbiota of patients with inflammatory bowel diseases

The intestinal population of Escherichia coli is increased in patients with inflammatory bowel disease (IBD), but the reason for this elevation, the particular features of these bacteria and their potential role in the pathogenesis of the disease are not known. The present study was undertaken to investigate the adherence abilities and some virulence properties of a collection of 131 E. coli isolates cultured from rectal biopsies of 23 subjects diagnosed with ulcerative colitis (UC), 8 with Crohns disease (CD) and 23 control patients from southern Brazil. The adherence abilities of the bacteria were investigated in vitro, using HEp-2 epithelial cells in assays of 3 and 6h of bacteria-cell contact. The isolates were screened by PCR with primers for the following virulence genetic markers: plasmid of aggregative adhesion (pAA) and the aggregative adherence fimbriae R (aggR), E. coli attaching and effacing (eae), invasion-associated locus (ial), invasion plasmid antigen H (ipaH) and Shiga citotoxin-encoding (stx) genes. HEp-2 cells aggregative adherent E. coli strains, as detected in the 3h adherence assay, were found in 14/23 (60.9%) patients with UC, 7/8 (87.5%) with CD and in 7/23 (30.4%) controls (p=0.011). Virulence genetic markers were detected in strains of 9 patients with UC (39.1%), but in none of CD or control group. Two of these UC patients had strains harboring both pAA and aggR, one had strains positive for aggR, four had strains positive for eae and two had strains positive for stx. These results suggest that the augmented population of E. coli on the rectal mucosa of IBD patients, particularly of those diagnosed with UC, is mostly comprised of aggregative adherent strains, some of which possessing classical virulence markers of E. coli.

Reduced etiological role for enteropathogenic Escherichia coli in cases of diarrhea in Brazilian infants

ABSTRACT Previously common in Brazil, enteropathogenic Escherichia coli (EPEC) strains of serogroups O55, O111, and O119 are now rare, while enteroadherent strains other than EPEC, belonging to serogroups such as O125, were prevalent among 126 diarrheic infants less than 1 year old who were surveyed. None of these strains had the EPEC bundle-forming pilus (bfpA) gene.

Concurrent infection in a dog and colonization in a child with a human enteropathogenic Escherichia coli clone.

Univ Estadual Paulista Julio Mesquita Filho, Inst Biociencias, Dept Microbiol & Imunol, Botucatu, SP, Brazil

Niche-Specific Association of Aeromonas Ribotypes from Human and Environmental Origin

A total of 88 Aeromonas isolates from distinct locations and sources (39 from extraintestinal infections, 31 from diarrhoeic, ten from non‐diarrhoeic faeces, all human, and eight from fresh water) were subjected to phenospecies identification, serotyping, ribotyping and detection of some virulence markers. The strains belonged to four different phenospecies marked by 19 O serogroups and 38 ribotypes. No strong correlation between these parameters was found, and no group, as defined by the typing methods, could be characterized with a particular set of virulence markers. There was a clear association of ribotypes with the source of the strains. Cluster analysis allowed the identification of a complex of ribotypes belonging to distinct but related sources, including clinical and environmental isolates. These results suggest that ribotyping may be an epidemiological tool suitable for the study of Aeromonas infections.

Effect of immersion and inoculation in ovo of Lactobacillus spp. in embryonated chicken eggs in the prevention of Salmonella Enteritidis after hatch.

The protection level against Salmonella Enteritidis was evaluated in chickens after in ovo treatment with different species of Lactobacillus spp. inoculated into the air cell or by immersion in broth culture. Two hundred forty embryonated eggs were distributed into 8 groups, corresponding to treatments with Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus salivarius, and control. On d 18 of incubation, 4 groups were inoculated with 0.1 mL of inoculum in the air cell and 4 groups were immersed for 3 min in culture of each treatment. Two days after hatching, 0.5 mL of Salmonella Enteritidis culture was inoculated by the intraesophageal route. On d 5 of life, the chicks were euthanized and the ceca were processed to obtain Salmonella Enteritidis counts. There was no decrease in Salmonella Enteritidis colonization of chick ceca, regardless of treatment or route of administration. Lactobacillus spp. samples used in the treatment showed no probiotic potential in chicks when inoculated in ovo, in relation to Salmonella Enteritidis inhibition in poultry ceca.

Evaluation of in vitro and in vivo adhesion and immunomodulatory effect of Lactobacillus species strains isolated from chickens

This study aimed to characterize the in vitro and in vivo adhesion and immunomodulatory effect of Lactobacillus strains isolated from chickens. Lactobacillus samples isolated from 65-wk-old birds were identified by PCR; their adhesion was evaluated in vitro via basement membrane-type cell matrix and in vivo through carboxyfluorescein succinimidyl amino ester staining inoculation in 1-d-old birds and duodenum, jejunum, ileum, and cecum collections at 1, 4, 12, and 24 h after inoculation. The 5 best adhesive samples at the in vitro test formed a pool for total IgA and IgG measurement in sera and intestinal fluid. The birds were divided into groups by inoculation scheme: group 1 was treated with a pool of Lactobacillus spp. at 2-d-old and challenged 1 d later with Salmonella Enteritidis and then treated again with a pool of Lactobacillus spp. at 4 d of age; group 2 was treated with a pool of Lactobacillus spp. at 2 and 4 d of age; group 3 was challenged with Salmonella Enteritidis at 3 d of age; and group 4 was a negative control. Collections were taken at 7, 14, 21, 28, and 35 d after the first inoculation. The results suggest that basement membrane matrix use represents an important technique for triage of samples for subsequent in vivo evaluation and that carboxyfluorescein succinimidyl amino ester staining is efficient for identifying this bacterial characteristic. The Lactobacillus-treated groups (1 and 2) presented the highest IgA concentrations at the end of the experiment (12,054.6 and 10,568.4 ng/mL, respectively). The group 2 IgG values in intestinal fluid exceeded those of the other 3 groups (P < 0.05), peaking at 6.419 ng/mL. In most serum collections, the Lactobacillus-treated groups (1 and 2) did not differ significantly in IgG concentrations (P > 0.05), whereas group 3 presented the highest concentration of this antibody. It is concluded that there was greater adhesion of strains in the cecum and an important correlation between in vitro and in vivo results. These results also suggest the immunomodulatory action of Lactobacillus spp. in the chicken.

Use of organic acids and competitive exclusion product as an alternative to antibiotic as a growth promoter in the raising of commercial turkeys

A study was conducted to investigate the effects of organic acids (OA) and competitive exclusion product (CE) on growth performance, intestinal morphology, and concentration of volatile fatty acids in the cecal content. The experiment lasted for 10 wk. Four hundred twenty 1-d-old female commercial cross turkey poults (British United Turkeys, BUT Big 9) were distributed into 4 treatments with 5 replicates/pen of 21 birds each. The birds were fed a basal diet without growth promoter (control), diet with lincomycin (44 mg/kg), diet with organic acids (2 g/kg), and diet with product of CE (10(9) cfu/kg). Dietary levels of other nutrients, housing, and general management practices were similar for all treatments. On the first week (d 0-7), the BW and BW gain of the birds that fed diets with OA were lower than in the control group. In the fattening phase (d 28-70), the feed intake of the OA-treated group was lower than compared with the control. The birds that received diet with OA and CE product presented higher concentrations of propionic acid, at 14 d, and butyric acid in cecal content at 28, 56, and 70 d, compared with the control. Dietary inclusion of additives had no significant effects on intestinal villus height, crypt depth, and villus:crypt ratio. Organic acids had negative effects either on early gain or feed intake throughout the study. Because the test was conducted under controlled experimental conditions, the additives that showed results similar to those found by using antibiotics should be studied further in commercial farms to obtain results that can be incorporated into practice.