Prodigiosin-Producing Serratia marcescens as the Causal Agent of a Red Colour Defect in a Blue Cheese.

Technological defects in the organoleptic characteristics of cheese (odour, colour, texture, and flavour) reduce quality and consumer acceptance. A red colour defect in Cabrales cheese (a traditional, blue-veined, Spanish cheese made from raw milk) occurs infrequently but can have a notable economic impact on family-owned, artisanal cheesemaking businesses. This work reports the culture-based determination of Serratia marcescens as the microbe involved in the appearance of red spots on the surface and nearby inner areas of such cheese. Sequencing and analysis of the genome of one S. marcescens isolate, RO1, revealed a cluster of 16 genes involved in the production of prodigiosin, a tripyrrole red pigment. HPLC analysis confirmed the presence of prodigiosin in methanol extracts of S. marcescens RO1 cultures. The same was also observed in extracts from red areas of affected cheeses. The strain showed low survival rates under acidic conditions but was not affected by concentrations of up to 5% NaCl (the usual value for blue cheese). The optimal conditions for prodigiosin production by S. marscescens RO1 on agar plates were 32 °C and aerobic conditions. Prodigiosin has been reported to possess antimicrobial activity, which agrees with the here-observed inhibitory effect of RO1 supernatants on different bacteria, the inhibition of Enterobacteriaceae, and the delayed development of Penicillium roqueforti during cheesemaking. The association between S. marcescens and the red colour defect was strengthened by recreating the fault in experimental cheeses inoculated with RO1. The data gathered in this study point towards the starting milk as the origin of this bacterium in cheese. These findings should help in the development of strategies that minimize the incidence of pigmenting S. marcescens in milk, the red defect the bacterium causes in cheese, and its associated economic losses.

Appropriateness of outpatient gastrointestinal endoscopy in a non-academic hospital.

AIM: To assess the appropriate use and the diagnostic yield of upper gastrointestinal endoscopy and colonoscopy in this subgroup of patients. METHODS: In total, 789 consecutive outpatients referred for gastrointestinal (GI) endoscopy [381 for esophagogastroduodenoscopy (EGD) and 408 for colonoscopy] were prospectively enrolled in the study. The American Society for Gastrointestinal Endoscopy (ASGE) guidelines were used to assess the relationship between appropriateness and the presence of relevant endoscopic findings. RESULTS: The overall inappropriate rate was 13.3%. The indications for EGD and colonoscopy were, respectively, appropriate in 82.7% and 82.6% of the exams, uncertain in 5.8% and 2.4% and inappropriate in 11.5% and 15%. The diagnostic yield was significant higher for EGDs and colonoscopies judged appropriate and uncertain when compared with those considered inappropriate (EGD: 36.6% vs 36.4% vs 11.4%, P = 0.004; Colonoscopy: 24.3% vs 20.0% vs 3.3%, P = 0.001). Of the 25 malignant lesions detected, all but one was detected in exams judged appropriate or uncertain. CONCLUSION: This study shows a good adherence to ASGE guidelines by the referring physicians and a significant increase of the diagnostic yield in appropriate examinations, namely in detecting neoplastic lesions. It underscores the importance that the appropriateness of the indication assumes in assuring high-quality GI endoscopic procedures.

A comparative study of two methods of colonic cleansing before colonoscopy.

BACKGROUND/AIMS: good colonic preparation is essential to perform a complete and safe colonoscopy. The preparation used in the Endoscopy Unit was adopted after testing it against the classic 4-liter polyethylene glicol (PEG) preparation (Klean-Prep). Recently a new 3-liter PEG preparation was commercialised in Portugal, Endo-Falk, which appeared to be simpler and effective. The present study compared the preparation we usually use (a combination of 4 tablets of bisacodyl with 2-liter PEG and enemas) with this new preparation. METHODOLOGY: we enrolled 305 patients in 2 groups. Group 1 was given our usual preparation, as described above and group 2 was given the new 3-liter preparation, Endo-Falk. All patients were ambulatory, and only patients undergoing total colonoscopies were included. Patients with benign or malignant stenosis and patients who had previously undergone colorectal resection were excluded. Preparation was graded as good when there were no stools and little liquid in the colon, fair when there were stools or liquid that could be aspirated and did not obscure the mucosa and bad when stools or excess liquid prevented an adequate view of the surface or precluded polipectomy. RESULTS: The present study included 164 male and 141 female patients, with a mean age of 61.3 years (no difference between the demographic data). In group 1 the preparation was good in 57.5%, fair in 28.5% and bad in 14% of patients and in group 2 the preparation was good in 33.1%, fair in 48.9% and bad in 18% (p < 0.001). Colonoscopies were complete in 89.9% of all patients. CONCLUSIONS: The usual preparation was better than the new 3-liter PEG solution.