Bacteriology and epidemiology of pseudomonas aeruginosa isolated from clinical specimens
Since the advent of chemotherapy the great renaissance for the various infections has attributed to the human life and the succeeding discovery of antibiotics after penicillin by Alexander Fleming has given so great contributions to human society at the clinical point of view.
By the antibiotics, however, an undesirable superinfection has taken place as equivalent as tumorsuppressing agents, steroids and various radiotherapies, ets. As a result, the presence of resistant staphylococci, fungi and gram-negative bacteria including overwhelming number of Pseudomonas aeruginosa has come to embarrass our medical personnel as a great problem to the treatment of disease in the clinic.
According to Sambe et al. in 1964 Pseudomonas aeruginosa acted as primary invader in a group of newborn infants revealing acute suppurative otitis media at nursery of a hospital ward for the definite period of time.
Biochemical characteristics of Pseudomonas aeruginosa itself are different from many textbooks and its pigment production, immunological features, antigenic structures and phages are well to be konwn in the recent years. Non-pigment formers were reported about 4 per cent in the clinical materials by Gaby and Free in 1953 and yet their culture from 2clinical specimens.
At this point the emphasis on this bacteria has become a very important fact to identify by a rapid laboratory work-up available all over the world.
Looking over the status of our country at the present time it is likely to be used in a blind administration of bread-spectrum antibiotics which are not really evaluated on the clinical and etiological(culture and sensitivity) basis.
For these reasons the author has attempted to establish not only the way of rapid and exact identification of the bacteria but also the clinical applications through the experimental studies.
The major emphasis of this bacteria pertaining to the observation of its sensitivity to the antibiotics, a confirmation of a part of its infectivity by means of serotyping and an affirmation of pathogenetic differences by pigment production have been studied on 71 strains of Pseudomonas aeruginosa in which 28 strains were isolated from 116 gram-negative bacteria from the cultures of 430 clinical specimens obtained from out-patients and hospitalized patients in the department of Ear, Nose and Throat and 43 strains were provided by the Central Laboratory of Severance Hospital, Yonsei University College of Medicine,
respectively, for the period of one year from August 14, 1968 to August 13, 1969.
As control group 18 gram-negative bacteria were used from the cultures of 349 materials of the normal subjects and the results are summarized as follows:
1. Among 220 clinical materials in the diseased ears it amounted to 114 on the left and 106 on the right. The isolated gram-negative bacteria were 94 in number, in which 48 (35.8%) were on the left and 46 (34.3%) on the right. Strains of Pseudomonas aeruginosa isolated from ears were 22 occupying 78.5 per cent of total 28.
2. According to the diseases for the 28 strains of Pseudomonas aeruginosa from the clinical materials of the department of Ear, Nose and Throat, 18 (64.3%) were from chronic suppurative otitis media and 5 (21.4%) from chronic paranasal sinusitis. The high incidence of this bacteria encountered here are considered to be the outcome of superinfection.
3. In the data shown on the cultures of 329 in which 246 were normal ears and 103 normal tonsils, 18 (5.1%) were gram-negative bacteria in which 11 were isolated from tonsils, 4 from left ears and 3 from right ears. Only one strain of Pseudomonas aeruginosa was identified from tonsils.
4. It is preferred to be able to reach rapid and exact identification by means of Patho Tec-Co's cytochrome oxidase reagent, Hugh-Leifson media, and King A and B media with the aid of general biochemical characteristics.
5. Upon the observation of pigment production of Pseudomonas aeruginosa one should keep one's eyes on King A and B media more than 3 days to confirm and the latter is considered excellent either for the identification or for the isolation of the bacteria.
6. The sensitivity patterns according to the antibiotics for four different strains of pigment production revealed Colimycin, Terramycin, Neomycin, Kanamycin, Streptomycin in order and Colimycin was the most sensitive one of aoo the antibiotics used, while Chloramphenical the most resistant and there were no difference of sensitivity in a broad sense for each strain.
7. The pathogenesis for each strain performed on the rabbits was consistent with the recent trend, that is, strains of pyorubin and fluorescin only gave almost equal lesions, non-pigment former, the next and strain of the associated pyocyanin and fluorescin, the last.
8. According to the serotypes by means of Homma for 28 strains of Pseudomonas
aeruginosa obtained from the clinical specimens of the department of Ear, Nose and
Throat, the types and numbers of strains were classified as: T^^7: 9, T^^10 :8, T^^9 :5, T^^11 :2, T^^5 : 2 and unidentified: 2.
With these performed heretofore the author is convinced that the improvement of the technique at a laboratory and that even the management of various infections will give better help in our country and finally, with earlier establishment of serotyping by the heat-stabel antigens not affected by dissociation will give a good tool for the study of the true source of infections.