SYNOPSIS A new serotyping method for Klebsiella species using indirect immunofluorescence is described. Nonspecific fluorescence has been minimized by carrying out the capsular antigen-antibody reaction at pH 9 0.Commercial antisera have been tested with the 72 antigenic types of Klebsiella, and appropriate dilutions of each pool and specific antisera have been proposed for use in routine typing. Dilutions were chosen to allow strong fluorescence with each type and its specific antiserum and minimal fluorescence with cross reacting antisera.Where the pool antisera gave a weak reaction for one or more of the component types, it is recommended that the specific antisera for these types be added to the pool dilution.The few remaining cross reactions, with the pool and specific antisera in test dilution, are listed in a table. The unique cross reacting patterns of particular types have been found to be useful in identification.Typing Klebsiella by the fluorescent antibody technique is easy to perform and interpret; the results are reproducible, and it is less expensive than the existing capsular swelling method as it is more sensitive and requires less concentrated antisera. This new method of typing should facilitate detailed epidemiological studies of the mode of transmission of Klebsiella species in hospitals and thus allow more effective infection control measures to be instituted.

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The microbial quality of lettuce (Lactuca sativa L. var. “Ostinata”) cultivated in a hydroponic system was evaluated. Over a 3-month study period, samples of lettuce, nutrient solution, and peat-vermiculite growing mixture from the greenhouse were analyzed for total aerobic bacteria, yeasts, molds, and coliforms. There was a consistent amount of each type of organism occurring within each sample group for a given month, and the numbers of aerobic bacteria and coliforms present were generally similar to those reported for lettuce and leafy vegetable crops propagated by the conventional method of agriculture. Over the study period, the modal values for each type of organism in lettuce were: aerobic bacteria, 7.9 × 106 CFU/g (range of 3.8 × 104 to 2.3 × 108); coliforms, 1.5 × 104 CFU/g (range of none detected to greater than or equal to 5.3 × 107); molds, 2.9 × 103 CFU/g (range of 1.2 × 102 to 5.3 × 104); and yeasts, 2.4 × 104 CFU/g (range of 6.9 × 102 to 2.3 × 106). The primary organisms associated with the growing system were Citrobacter freundii, Enterobacter cloacae, and Enterobacter agglomerans. No organisms of human health concern (i.e. Salmonella spp., Clostrium botulinum, Escherichia coli, or Staphylococcus aureus) were detected in the samples. The bacteriology of lettuce produced for market by this type of hydroponic farming and packaging appears to be generally comparable to that of field-grown lettuce and to present no unique microbiological hazards to consumers.

(Casewell, 1975;Edwards and Ewing, 1968

SUMMARYThe fluorescent antibody technique was used to investigate an epidemic of Klebsiella infection in a urological ward and to trace the probable source to a contaminated sink in the treatment room. It was also shown that cross infections by particular capsular types were very common within each ward. Certain types of Klebsiella occurred in cut-flower water but could not be associated with the types infecting the patients.Antibiotic resistance patterns within one capsular type were found to vary whether the type was from different sources in one patient or from different patients in the same ward. One capsular type was observed to develop resistance to increasing numbers of antibiotics over a 3-year period. This was probably due to the acquisition of R-plasmids. There also appeared to be a relation between capsular type and the site of infection.The frequency of Klebsiella infections in the urological wards dropped significantly after up-grading the treatment room, improving catheter storage and reducing ampicillin use.