Characterization of the Digestive Tract Microbiota of Hirudo orientalis (Medicinal Leech) and Antibiotic Resistance Profile :

A total of 193 strains representing 14 different Aeromonas genomospecies were evaluated for 63 phenotypic properties to create useful tables for the reference identification of mesophilic aeromonads. Only 9 of 62 biochemical tests (14%) yielded uniform results, and the fermentation of certain carbohydrates was found to be linked to specific species. A number of unusual or aberrant properties for the genus Aeromonas were also detected in the collection of 428 strains (193 in the phenotypic study, 235 in a retrospective review). These tests included susceptibility to the vibriostatic agent, fermentation of m-inositol and D-xylose, hydrolysis of urea, and the lack of cytochrome oxidase activity. Fermentation of melibiose was linked to raffinose fermentation in all Aeromonas species except A. jandaei. Keys are provided for clinical laboratories choosing to identify aeromonads to species level based upon initial Møeller decarboxylase and dihydrolase reactions. In addition, several new tests were identified that help to separate members of the A. caviae complex (A. caviae, A. media, and A. eucreonophila).

The innate immune system is present in all animals and is a crucial first line of defence against pathogens. However, animals also harbour large numbers of beneficial microorganisms that can be housed in the digestive tract, in specialized organs or on tissue surfaces. Although invertebrates lack conventional antibody-based immunity, they are capable of eliminating pathogens and, perhaps more importantly, discriminating them from other microorganisms. This Review examines the interactions between the innate immune systems of several model invertebrates and the symbionts of these organisms, and addresses the central question of how these long-lived and specific associations are established and maintained.

Increasing resistance to quinolones among campylobacter isolates from humans has been reported in Europe and Asia, but not in the United States. We evaluated resistance to quinolones among campylobacter isolates from Minnesota residents during the period from 1992 through 1998. All 4953 campylobacter isolates from humans received by the Minnesota Department of Health were tested for resistance to nalidixic acid. Resistant isolates and selected sensitive isolates were tested for resistance to ciprofloxacin. We conducted a case-comparison study of patients with ciprofloxacin-resistant Campylobacter jejuni isolated during 1996 and 1997. Domestic chicken was evaluated as a potential source of quinolone-resistant campylobacter. The proportion of quinolone-resistant C. jejuni isolates from humans increased from 1.3 percent in 1992 to 10.2 percent in 1998 (P<0.001). During 1996 and 1997, infection with quinolone-resistant C. jejuni was associated with foreign travel and with the use of a quinolone before the collection of stool specimens. However, quinolone use could account for no more than 15 percent of the cases from 1996 through 1998. The number of quinolone-resistant infections that were acquired domestically also increased during the period from 1996 through 1998. Ciprofloxacin-resistant C. jejuni was isolated from 14 percent of 91 domestic chicken products obtained from retail markets in 1997. Molecular subtyping showed an association between resistant C. jejuni strains from chicken products and domestically acquired infections in Minnesota residents. The increase in quinolone-resistant C. jejuni infections in Minnesota is largely due to infections acquired during foreign travel. However, the number of quinolone-resistant infections acquired domestically has also increased, largely because of the acquisition of resistant strains from poultry. The use of fluoroquinolones in poultry, which began in the United States in 1995, has created a reservoir of resistant C. jejuni.