Klebsiella capsular type versus site of isolation.

More than 1750 clinical isolates of klebsiella were collected over a period of six years from two different hospitals and capsular typed by the fluorescent antibody technique. A correlation was made between type and site of isolation. Many types were found to be associated more frequently with one site, which suggested a predilection of some capsular types for certain sites of infection. The site may also be a factor contributing to the virulence of a particular type. A greater antibiotic resistance was often noted in types isolated from their predominant sites; however, antibiograms were not consistent for a type from a given site. The combination of site specificity, resistance, and another 'virulence factor' may all be involved in the determination of a pathogenic strain.

Epidemiological study of klebsiella infection in the special care baby unit of a London hospital.

Of the babies admitted to the Special Care Baby Unit of the Royal Free Hospital over 20 months, 10.2% were infected or colonised by klebsiella. The fluorescent antibody technique was used to identify epidemics caused by three strains: capsular type 8 K. aerogenes, type 68 K. oxytoca, or type 13 K. aerogenes, each of which was predominant at a different time, exhibited a difference in virulence, and showed a predilection for different sites of infection. Intestinal colonisation was frequently followed by the presence of sepsis in other sites by the same capsular type. Antibiotic administration led to a higher incidence of klebsiella infection, while the widespread use of compounds containing hexachlorophane could have contributed to skin colonisation and infection by klebsiella. An environmental survey indicated that 1% Hycolin failed to disinfect the incubators, that the babies were the reservoirs of the organisms, and that transmission was due to inadequate hand-washing of nurses and mothers. The mothers were found to have been uninformed of hygienic techniques. They were observed in various practices which could have contributed to the spread of the organism, including contaminating communal areas and handling babies other than their own. It has been recommended that the mothers of premature infants be instructed in the hygienic measures required in dealing with this susceptible population and that the nursing and medical staff be more strict in their own observance of these procedures.

The use of a fluorescence typing method in an epidemiological study of Klebsiella infection in a London hospital.

The 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.

A new serotyping method for Klebsiella species: development of the technique.

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.

A new serotyping method for Klebsiella species: evaluation of the technique.

A new indirect fluorescent typing method for Klebsiella species is compared with an established method, capsular swelling. The fluorescent antibody (FA) technique was tested with standards and unknowns, and the results were checked by capsular swelling. Several unknowns were sent away for confirmation of typing, by capsular swelling. The FA method was also tried by a technician in the routine department for blind identification of standards. Fluorescence typing gives close correlation with the established capsular swelling technique but has greater sensitivity; allows more econimical use of expensive antisera; possesses greater objectivity as it requires less operator skill in the reading of results; resolves most of the cross reactions observed with capsular swelling; and has a higher per cent success rate in identification.