Chapter 1 : Disseminators Aloft?

Abstract:

This chapter on disseminators aloft talks about research on gene cassettes, integrons, and antibiotic resistance genes carried out by a group of Mendel’s compatriots at the University of Veterinary and Pharmaceutical Sciences in Brno. Their studies would have greatly appealed to Mendel the scientist, but also, for their practical implications, to Mendel the naturalist and gardener. The Brno team studied over 250 E. coli isolates from cloacal smears of young blackheaded gulls from three different nesting sites. The major type of resistance was against tetracycline (19% of isolates), followed by ampicillin (12%), streptomycin (9%), and sulfonamides (8%). Nine isolates carried integrons. They set out to quantify the abundance of six tetracycline resistance genes in wastewater lagoons at cattle feedlots, to assess the effects, if any, of different strategies for the use of antibiotics. Jonas Waldenstrom and his coworkers took cloacal swabs from lapwings and other species, together with fecal samples from barnacle geese and cattle, in three locations in Gotland during late spring and early summer. The organisms showed an uneven distribution: H. canadensis was restricted to geese, while all except one of the UPTC isolates occurred in shorebirds. The problem is exacerbated by the tenacity with which bacteria (especially salmonellae) adhere to leaf surfaces and the imperfect techniques as yet available to wash them away.