Recent outbreaks of disease caused by Escherichia coli O157:H7 have focused much attention on this newly emerged pathogen. Identification of the H7 flagellar antigen is critical for the confirmation of E. coli O157:H7; however, clinical isolates are frequently nonmotile and do not produce detectable H antigen. To further characterize nonmotile isolates (designated NM), we developed a PCR-restriction fragment length polymorphism (PCR-RFLP) test to identify and characterize the gene encoding the H antigen (fliC) in E. coli. The entire coding sequence of fliC was amplified by PCR, the amplicon was restricted with RsaI, and the restriction fragment pattern was examined after gel electrophoresis. Two hundred eighty E. coli isolates representing serotypes O157:H7 and O157:NM, flagellar antigen H7 groups associated with other O serogroups, and all other flagellar antigen groups were analyzed. A single restriction pattern (pattern A) was identified for O157:H7 isolates, O157:NM isolates that produced Shiga toxin (formerly Shiga-like toxin or verotoxin), and 16 of 18 O55:H7 isolates. Flagellar antigen group H7 isolates of non-O157 serotypes had one of three banding patterns distinct from pattern A. A wide variety of patterns were found among isolates of the other 52 flagellar antigen groups; however, none was identical to the O157:H7 pattern. Thirteen of 15 nonmotile strains that did not produce the A pattern had patterns that matched those of other known H groups. The PCR-RFLP in conjunction with O serogroup determination will be useful in identifying E. coli O157:H7 and related strains that do not express immunoreactive H antigen and could be expanded to include other clinically important E. coli strains.

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The ex vivo infection models presented here should be helpful in the screening of novel antimicrobials and constitute a prerequisite for future clinical studies.

A non‐toxic hydrolytically fast‐degradable antibacterial hydrogel is herein presented to preemptively treat surgical site infections during the first crucial 24 h period without relying on conventional antibiotics. The approach capitalizes on a two‐component system that form antibacterial hydrogels within 1 min and consist of i) an amine functional linear‐dendritic hybrid based on linear poly(ethylene glycol) and dendritic 2,2‐bis(hydroxymethyl)propionic acid, and ii) a di‐N‐hydroxysuccinimide functional poly(ethylene glycol) cross‐linker. Broad spectrum antibacterial effect is achieved by multivalent representation of catatonically charged β‐alanine on the dendritic periphery of the linear dendritic component. The hydrogels can be applied readily in an in vivo setting using a two‐component syringe delivery system and the mechanical properties can accurately be tuned in the range equivalent to fat tissue and cartilage (G′ = 0.5–8 kPa). The antibacterial effect is demonstrated both in vitro toward a range of relevant bacterial strains and in an in vivo mouse model of surgical site infection.

Restriction fragment length polymorphism analysis of a PCR-amplified DNA fragment of the gene coding for 16S rRNA was performed on 148 previously characterized strains of Campylobacter, Helicobacter, Arcobacter, and Wolinella succinogenes and 13 Campylobacter-like isolates. These strains included clinical, animal, and environmental isolates. PCR amplification generated a 283-bp fragment from all species. The amplicon from each strain was digested with six restriction endonucleases (AccI, AvaI, DdeI, HaeIII, HpaII, XhoI). DdeI was useful for the initial grouping of the strains. Additional discrimination within the different DdeI groups was obtained with AccI, HaeIII, HpaII, and XhoI digestions. The PCR-restriction fragment length polymorphism analysis allowed for the discrimination of members of the genus Campylobacter from members of closely related genera and discrimination between Campylobacter species. The proposed method is simple and rapid and can be useful for the routine identification of Campylobacter-like organisms in clinical or epidemiologic studies.

A phenotypic variant of Escherichia coli serotype O157:H7 (G5101) was isolated from a patient with bloody diarrhea. Strain G5101 does not ferment sorbitol but is ␤-D-glucuronidase and urease positive. Serotyping and colony hybridization using a serotype-specific DNA probe confirmed that the isolate was O157:H7. G5101 produces Shiga-like toxins I and II and contains an eae gene that is highly conserved in the O157:H7 serotype. This strain would have been missed by laboratories that screen for the sorbitol-negative, ␤-Dglucuronidase-negative phenotype in isolating E. coli O157:H7 from clinical and food specimens.

11A bio-inspired coating consisting of pectin (polygalacturonic acid) and cationic cellulose nano-12 fibers were successfully produced by the Layer-by-layer method. The build-up and the morphol-13 ogy of the resulting coatings were studied with spectroscopic ellipsometry and atomic force mi-14 croscopy, respectively. The coating was able to survive the exposure of a simulated gastric fluid, 15 but was partially degraded upon exposure to pectinase enzyme, which simulate the action of the 16 microbial symbionts present in the human colon. Prior to exposure, the oxygen permeability co-17 efficient of the coating (0.033 ml (STP) mm m -2 day -1 atm -1 at 23°C and 20% RH) was in the 18 same order of magnitude as for ethylene vinyl alcohol films (0.001-0.01 ml (STP) mm m -2 day -19 1 atm -1 ). However after exposure to the mimicked gastrointestinal (GI) tract conditions, the con-20 tribution of coating to the overall barrier properties was not measurable. 21 22

A PCR method for rapid identification of Campylobacter fetus subsp. fetus was evaluated. A fragment of the gene coding for 16S rRNA was amplified from crude cell lysates of 18 C. fetus strains and 30 strains representing other Campylobacter species and subspecies. The amplicons were probed by dot blot hybridization with a digoxigenin-labeled C. fetus-specific oligonucleotide probe. The probe reacted only with C. fetus subsp. fetus and C. fetus subsp. venerealis and may be useful for rapid identification in clinical laboratories.