An evaluation of two methods of bacteriocine typing of organisms of the genus Proteus.

Al-Jumaili, I J

doi:10.1136/jcp.28.10.788

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“…In addition to the 1000 strains dealt with here, 204 isolates of epidemiological importance were also typed using this system and compared with other typing methods. The results appear in this issue (Al-Jumaili, 1975). …”

Section: Reproducibility Of the Systemmentioning

confidence: 76%

Bacteriocine typing of Proteus.

Al-Jumaili¹

1975

J Clin Pathol

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SYNOPSIS A method of typing isolates of Proteus mirabilis and Proteus vulgaris is described based on the sensitivity of the organisms to bacteriocine. Twelve standard proteocine producing strains were selected from a large number of isolates tested, and from these liquid proteocine preparations were prepared. The sensitivities of 1805 isolates to these 12 preparations were then determined and none was found to be untypable. From the results a bacteriocine typing system has been developed.Bacteriocine typing has been shown to be successful in the characterization of specific strains of several genera of Gram-negative bacilli. Such typing enabled Abbott and Shannon (1958), Abbott and Graham (1961), and Gillies (1964) to study outbreaks of dysentery caused by Shigella sonnei. Likewise a detailed study of the bacteriocines (pyocines) produced by Pseudomonas aeruginosa led to typing schemes based on pyocine production (Wahba, 1963;Darrell and Wahba, 1964;Gillies and Govan, 1966). Linton (1960) described a method of colicine typing of strains of Escherichia coli. However, the production of bacteriocines (proteocines) by members of the genus Proteus has been little studied. An initial investigation into the typing of strains of Proteus by this method was unsatisfactory as only three proteocine types were discovered (Cradock-Watson, 1965 ing. Before use, 12 ml amounts of melted medium were distributed into sterile 9 cm diameter plastic Petri dishes, and the plates were dried in the incubator at 37°C for 2 hours. SOURCE OF STRAINSFive hundred and sixty-eight Proteus strains were obtained from clinical specimens from hospital patients during a period of nine months. The majority of organisms were isolated from urine and smaller numbers of pus, nasal, and wound swabs. Duplicate isolates from the same patients were avoided. BIOCHEMICAL IDENTIFICATIONThe conversion of phenylalanine to phenylpyruvic acid and the hydrolysis of urea on Christensen's medium were used as criteria to place non-lactosefermenting Gram-negative bacilli in the genus Proteus. Proteus mirabilis and Proteus vulgaris were identified on the basis of indole and H2S production, decarboxylation of ornithine, and fermentation of maltose. It was found that 59% were P. mirabilis and 41 % P. vulgaris. PRODUCTION OF PROTEOCINEFor production of proteocines, isolates are inoculated into 5 ml amounts of PP3 broth and incubated at 25°C. After 18 hours this culture is added to 50 ml of pre-heated (25°C) PP3 broth and incubated with orbital shaking at 25°C. After one hour mitomycin C (55 ,ug) is added to each culture to give a final concentration of 1 Htg mitomycin C per ml and the incubation is continued for a further 24 hours. The broth cultures are centrifuged at 3000 rev/min for 20 minutes, and the supernatant fluid is transferred to fresh sterile containers. Chloroform, 0 5 ml, is added to each flask, the contents of which are then thoroughly agitated for 5 minutes. The cultures are then 784 on 11 May 2018 by guest. Protected by copyright.

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Section: Reproducibility Of the Systemmentioning

confidence: 76%