Seasonal variation of eosinophil counts in histologically normal colonic mucosal biopsies.

INTRODUCTION: The eosinophil counts in colonic biopsies are affected by geographical and possibly seasonal variations. This study aims to investigate the significance of seasonal variations of eosinophil counts in histologically normal colonic mucosal biopsies. MATERIALS AND METHODS: This is a retrospective, cross sectional study that included 337 cases of normal colonic biopsies. The number of eosinophils per high power field was counted in the most densely populated area. The eosinophilic counts were compared among genders, age groups, biopsy sites and in various months and seasons. Two tailed T-test was used to compare means and a p value < 0.05 was considered significant. RESULTS: 173 (51%) of cases were from males. The age range was between 18-82 with the mean being 51.7 years (SD= 17.5). 181 (54%) biopsies were from the right colon and 156 (46%) from the left colon. There was a statistically significant difference between eosinophil counts in the right colon (mean 20.2, SD 13.2) and left colon (mean 13.8, SD10.1); p value <0.001. The mean eosinophil counts was highest in autumn (21.1) followed by spring (18.3). The counts in winter and summer were close (15.2 and 15.1 respectively). There was a statistically significant difference between counts in autumn and summer (p=0.013) and between autumn and winter (p=0.008). However, there was no statistically significant differences between autumn and spring counts (p=0.183). When stratified according to site, this pattern of statistical significance was observed in the right colon but not the left colonic mucosal biopsies. CONCLUSION: There are significant seasonal variations of eosinophil counts in normal colonic biopsies which are more pronounced in the right colon. Pathologists and gastroenterologists need to be aware of these variations and to take them into account when determining if a patient has tissue eosinophilia.

An abbreviated MLVA identifies Escherichia coli ST131 as the major extended-spectrum ß-lactamase-producing lineage in the Copenhagen area.

Rapid bacterial typing is a valuable and necessary tool in the prevention and detection of outbreaks. The purpose of this study was to adapt a multilocus variable number of tandem repeats analysis (MLVA) for analysis on a benchtop capillary electrophoresis instrument and compare the modified assay with multilocus sequence typing (MLST) for typing cefpodoxime-resistant Escherichia coli (E. coli). Further, we identified the causative resistance mechanisms and epidemiological type of infection for isolates producing extended-spectrum ß-lactamases (ESBLs). A collection of E. coli resistant to cefpodoxime was typed by MLST and a modified MLVA assay using a benchtop capillary electrophoresis instrument. Resistance mechanisms were identified by polymerase chain reaction (PCR) and sequencing. Patient history was examined to establish the epidemiological type of infection for ESBL-producing E. coli. MLVA yielded typing results homologous with MLST and it correctly identified E. coli sequence type (ST) 131 that was accounting for 45 % of all ESBL-producing isolates in the sample collection. The majority (76.7 %) of ESBL-producing isolates was healthcare-related and only 23.3 % of the ESBL-producing isolates were community-onset infections (COI), regardless of the ST. Patients with COI were significantly more often of female gender and younger age compared to healthcare-associated infections (HCAI) and hospital-onset infections (HOI). In conclusion, the modified MLVA is a useful tool for the rapid typing of E. coli and it identified ST131 as the predominating ESBL-producing lineage in Copenhagen. Healthcare-related infections were the predominant infection setting of ESBL-producing E. coli and the demographic characteristics differed between patients with COI and healthcare-related infections.