High frequency of antibiotic-resistant enterobacteria in the River Stour, Kent

Nonmedical Uses of Antibiotics: Time to Restrict Their Use?

The global crisis of antibiotic resistance has reached a point where, if action is not taken, human medicine will enter a postantibiotic world and simple injuries could once again be life threatening. New antibiotics are needed urgently, but better use of existing agents is just as important. More appropriate use of antibiotics in medicine is vital, but the extensive use of antibiotics outside medical settings is often overlooked. Antibiotics are commonly used in animal husbandry, bee-keeping, fish farming and other forms of aquaculture, ethanol production, horticulture, antifouling paints, food preservation, and domestically. This provides multiple opportunities for the selection and spread of antibiotic-resistant bacteria. Given the current crisis, it is vital that the nonmedical use of antibiotics is critically examined and that any nonessential use halted.

The speciation of coliform genera from above and below a sewer outfall and their susceptibilities to antimicrobial agents

The occurrence of coliforms in a small water course was shown to increase by a factor of thirty six below the outfall of a sewage treatment plant. Speciation of the bacteria from above and below the sewer outfall showed that Escherichia coli and Enterobacter species predominated. Drug resistance levels were significant in microorganisms from both sampling sites and the occurrence of a significant number of multiple-resistant microorganisms, particularly E. coli, is reported. Both E. coli and Enterobacter species from below the sewer outfall show a statistically significant increase in resistance to ampicillin and E. coli from below the outfall also shows a statistically significant increase in resistance to sulpha-methoxazole as compared with isolates from above the outfall.

Nalidixic acid as a selective agent for the isolation of enterobacteria from river water

Enterobacteria are more resistant to nalidixic acid than the majority of other Gram-negative organisms isolated from river water, so allowing their selection on MacConkey agar containing nalidixic aicd. Selection is further improved by anaerobic incubation which, with nalidixic acid, virtually eliminates oxidase-postivie strains such as Pseudomonas or Aeromonas.

Distribution of R plasmids among the O-antigen types of Escherichia coli isolated from human and animal sources

The O-antigen types of 600 independently isolated Escherichia coli strains from human feces have been determined, and the types have been related to the antibiotic resistance patterns of the strains. The relative abundance of each O-antigen type differed in the susceptible and resistant series of strains. The majority (86%) of the resistant strains carried R plasmids. Resistant E. coli (20.3%) were found associated with O-antigen types 8, 9 and 101, whereas the susceptible strains covered a wide range of O-antigen types. Examination of 174 resistant strains isolated from calf feces also showed a prevalence of O-antigen types 8, 9, 101 (24.1%), and it seems probable that strains expressing these three O-antigen types commonly carry R plasmids in the alimentary tracts of man and calves. The number of strains not typeable with the O sera available were similar in the human (12.5%) and the calf (11.5%) series. There are no grounds for distinguishing "human" from "calf" E. coli on the basis of their O-antigen reactions.