Different roles of host and bacterial factors in Escherichia coli extra-intestinal infections

Many host and bacterial factors contribute to the development of different Escherichia coli extra-intestinal infections. The aim of this study was to evaluate the roles of host and bacterial factors in different extra-intestinal E. coli infections. A total of 221 E. coli isolates collected from urine, bile and peritoneal fluid were included in this retrospective study. Four main phylogenetic groups of E. coli , 14 genetic determinants, static biofilm formation and antimicrobial resistance data were assessed, as well as the immunological status of the hosts. Group B2 was the most common phylogenetic group (30%), especially in cases of asymptomatic bacteriuria (ABU), urinary tract infection (UTI), acute appendicitis/gastrointestinal perforation, and spontaneous bacterial peritonitis (SBP), and was associated with elevated prevalence of papG  III , fimH , sfa , iha , hlyA , cnf1 , ompT and usp . Phylogenetic group A was most common in the isolates from asymptomatic bacteriocholia, biliary tract infection, and peritoneal dialysis (PD)-related peritonitis. There was similarity with respect to both phylogenetic groups and virulence factors in strains from faeces and ABU, and in strains from faeces and SBP/PD-related peritonitis. Host characteristics were important in patients with ABU, UTI, and SBP/PD-related peritonitis. Immunocompetence of hosts was associated with a relatively high prevalence of papG  II , afa and iha , and relatively low antimicrobial resistance to fluoroquinolones. This study demonstrates that, in most E. coli extra-intestinal infections, phylogenetic group B2 was predominant and was more virulent than the three other phylogenetic groups in the Taiwanese population studied. The diverse patterns of host and bacterial factors demonstrate that there were different host and bacterial factors dominating in different extra-intestinal E. coli infections.     

Interleukin‐18 gene 105A/C genetic polymorphism is associated with the susceptibility of Kawasaki disease

Interleukin‐18 (IL‐18)‐656T/G, ‐607A/C, and ‐137C/G promoter polymorphisms had been reported associated with Kawasaki disease (KD). An IL‐18 genetic A/C polymorphism at coding position 105 (rs549908) has been linked with asthma, rheumatoid, and systemic lupus erythematosus. We tested a hypothesis that the IL‐18 105A/C genetic polymorphism confers KD susceptibility. Study participants were Taiwanese KD patients and a healthy control group. Our data indicated that the frequency of C allele was significantly higher in the patient group (13.9%) than in the control group (2.7%; P<0.0001, odds ratio [OR]=5.93; 95% confidence interval [CI]=2.57–13.73). Therefore, persons with the C allele may have higher risk of deve loping KD. In addition, compared with the haplotype frequencies between case and control groups, the KD patients with TACC haplotype appeared to be a significant “at‐risk” haplotype compared with other haplotypes (OR: 4.62, 95% CI: 1.71–12.43; P=0.001). KD patient with the TAGA haplotype appeared to be a significant “protective” haplotype compared with other haplotypes (OR: 0.51, 95% CI:0.29–0.89; P=0.017). Our results suggest that 105A/C polymorphism and the haplotypes in IL‐18 gene are associated with the risk of KD in Taiwanese population. Clin. Lab. Anal. 23:71–76, 2009. © 2009 Wiley‐Liss, Inc.     

Feeding during acute diarrhea as a risk factor for persistent diarrhea

Dietary intake during diarrhea in children less than three years of age was estimated from information recorded on illustrated dietary forms used by children's caretakers during the first week of illness in a prospective community-based study of diarrheal diseases in Lima, Peru. The frequency of consumption and the amount consumed of food groups and selected commonly consumed foods were analyzed by the final duration of the diarrheal episode. Cereals were less frequently consumed during the acute phase of diarrheal episodes that ultimately became persistent (>14 days'duration), apparently shortening the duration of the episode by one day (median duration of four days in children not consuming vs three days in children consuming cereals during diarrhea, p <0.02 Kaplan-Meier logrank test). Only roots and tubers (mainly potatoes) were consumed in greater quantity during episodes that became persistent. There was no evidence that consumption of breast milk or non-maternal milk was associated with an alteration in diarrheal duration. This study provides further evidence of the beneficial effects of continuing feeding during diarrhea using foods available at the home level, especially cereals, which are commonly used in the diet of young children.     

Sentinel node biopsy in early breast cancer in Taiwan

The purpose of this study is to report the results of sentinel node (SN) biopsy for assessment of early breast cancer in Taiwan and to compare our results with those in other Asian countries and worldwide. We used methylene blue dye to identify SN in patients with clinically non-palpable breast mass and palpable breast mass smaller than 3 cm. We also explored the role of imprint cytology and immunochemical studies to identify metastatic cancer cells in the lymph nodes. A total of 221 procedures on 218 patients were performed by a single surgeon. The SN was identified in 85.5% of the cases. The overall accuracy of identifying tumors in SN was 97.4%, with a sensitivity of 90.9%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 96.4%. The use of immunochemical techniques helped to identify micrometastasis in SN or non-SN. Our results on SN biopsy with the dye method were similar to those reported from Japan and elsewhere. We concluded that sentinel node biopsy, together with the use of immunochemical techniques to identify micrometastatic foci, has allowed surgeons to decide at the time of surgery whether to perform axillary node dissection.     

Modulation of L-type Ca(2+) channels by distinct domains within SNAP-25

Cognate soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins are now known to associate the secretory vesicle with both the target plasma membrane and Ca(2+) channels in order to mediate the sequence of events leading to exocytosis in neurons and neuroendocrine cells. Neuroendocrine cells, particularly insulin-secreting islet beta-cells, t-SNARE proteins, 25-kDa synaptosomal-associated protein (SNAP-25), and syntaxin 1A, independently inhibit the L-type Ca(2+) channel (L(Ca)). However, when both are present, they actually exhibit stimulatory actions on the L(Ca). This suggests that the positive regulation of the L(Ca) is conferred by a multi-SNARE protein complex. We hypothesized an alternate explanation, which is that each of these SNARE proteins possess distinct inhibitory and stimulatory domains that act on the L(Ca). These SNARE proteins were recently shown to bind the Lc(753-893) domain corresponding to the II and III intracellular loop of the alpha1C subunit of the L(Ca). In this study, using patch-clamp methods on primary pancreatic beta-cells and insulinoma HIT-T15 cells, we examined the functional interactions of the botulinum neurotoxin A (BoNT/A) cleavage products of SNAP-25, including NH(2)-terminal (1-197 amino acids) and COOH-terminal (amino acid 198-206) domains, on the L(Ca), particularly at the Lc(753-893) domain. Intracellular application of SNAP-25(1-206) in primary beta-cells decreased L(Ca) currents by approximately 15%. The reduction in L(Ca) currents was counteracted by coapplication of Lc(753-893). Overexpression or injection of wild-type SNAP-25 in HIT cells reduced L(Ca) currents by approximately 30%, and this inhibition was also blocked by the recombinant Lc(753-893) peptide. Expression of BoNT/A surprisingly caused an even greater reduction of L(Ca) currents (by 41%), suggesting that the BoNT/A cleavage products of SNAP-25 might possess distinct inhibitory and positive regulatory domains. Indeed, expression of SNAP-25(1-197) increased L(Ca) currents (by 19% at 10 mV), and these effects were blocked by the Lc(753-893) peptide. In contrast, injection of SNAP-25(198-206) peptide into untransfected cells inhibited L(Ca) currents (by 47%), and more remarkably, these inhibitory effects dominated over the stimulatory effects of SNAP-25(1-197) overexpression (by 34%). Therefore, the SNARE protein SNAP-25 possesses distinct inhibitory and stimulatory domains that act on the L(Ca). The COOH-terminal 197-206 domain of SNAP-25, whose inhibitory actions dominate over the opposing stimulatory NH(2)-terminal domain, likely confers the inhibitory actions of SNAP-25 on the L(Ca). We postulate that the eventual accelerated proteolysis of SNAP-25 brought about by BoNT/A cleavage allows the relatively intact NH(2)-terminal SNAP-25 domain to assert its stimulatory action on the L(Ca) to increase Ca(2+) influx, and this could in part explain the observed weak or inconsistent inhibitory effects of BoNT/A on insulin secretion. The present study suggests that distinct domains within SNAP-25 modulate L(C) subtype Ca(2+) channel activity in both primary beta-cells and insulinoma HIT-T15 cells.     

Choroidal osteoma masquerading as central serous chorioretinopathy

We report a rare case of choroidal osteoma masquerading as central serous chorioretinopathy. A 39-year-old man complained of intermittent episodes of blurred vision in the left eye for 2 months. Fundus examination of the left eye showed a dome-shaped elevation at the macular center. Fluorescein angiography showed a patch of pinpoint leakage resulting in a well-defined pool of dye at the macular center. Initial diagnosis was recurrent central serous chorioretinopathy with sequelae in the left eye. Five months later, serous detachment recurred. Computerized tomography and ultrasonography showed a bony plaque at the choroid level, and choroidal osteoma was diagnosed.