Nursery Outbreak of Pseudomonas aeruginosa: Epidemiological Conclusions from Five Different Typing Methods

Bobo, Raymond A.; Newton, E. J.; Jones, Lois Faye; Farmer, L. H.; Farmer, J. J.

doi:10.1128/aem.25.3.414-420.1973

Cited by 21 publications

(7 citation statements)

References 11 publications

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“…Furthermore, the risk of serious infections, particularly septicemias, increases with extended hospitalization (23). Because of its antibiotic resistance and ubiquitous distri-bution in the hospital environment, P. aeruginosa is one of the most dangerous opportunistic pathogens (3,23,26,31,32). The need for a simple, reliable technique for comparing all "in-house" isolates of P. aeruginosa is evident.…”

Section: Resultsmentioning

confidence: 99%

Pyocin Typing of Pseudomonas aeruginosa: a Simplified Method

Jones¹,

Zakanycz²,

Thomas³

et al. 1974

Applied Microbiology

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A simplified method has been devised for typing Pseudomonas aeruginosa by pyocin production. Pyocins are produced as strains grow overnight in Trypticase soy broth (without glucose) plus 1% potassium nitrate. Because P. aeruginosa can use nitrate instead of oxygen as a terminal electron acceptor, mechanical shaking is not necessary, nor is induction by mitomycin C. Pyocins can now be produced in screw-cap tubes in a water bath or incubator. A total of 250 strains were tested as possible pyocin indicators, which included 60 strains already used in pyocin-typing systems. The final set contained 18 indicators which were chosen because (i) they had clear positive or clear negative reactions, thus eliminating reactions difficult to read, (ii) they had few zones due to bacteriophage lysis, and (iii) they were most sensitive in differentiating clinical isolates of P. aeruginosa. The final typing method was tested in several studies and the results were clear; thus definitive epidemiological conclusions could be made. Because it is simple to perform and easily automated, the new method should have application in many hospitals; however, it should be used only in carefully planned epidemiological studies. The method and its application are described in detail, and some pitfalls are discussed. Nosocomial infections caused by Pseudomonas aeruginosa continue to be a problem in many hospitals (3, 5, 8, 12, 16, 23). Within any institution there can be hundreds of different strains because it is often found in the human gut, and because it can survive and multiply in moist environments of the hospital. In any epidemiological study, a sensitive technique is required to compare these numerous strains. A number of methods have been used to differentiate P. aeruginosa in epidemiological studies. These epidemiological markers include

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Section: Resultsmentioning

confidence: 99%

Pyocin Typing of Pseudomonas aeruginosa: a Simplified Method

Jones¹,

Zakanycz²,

Thomas³

et al. 1974

Applied Microbiology

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“…Although the literature contains many descriptions of Pseudomonas typing methods such as colonial morphology, antimicrobial susceptibility, pyocin or phage typing, and 0-serotyping (3,13,34,42), these procedures are generally unreliable because of the inherent phenotypic variability of P. aeruginosa strains (29). Thus, Ogle et al (29) have used a DNA probe as an epidemiological marker for P. aeruginosa.…”

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Serial isolates of Pseudomonas aeruginosa from a cystic fibrosis patient have identical pilin sequences

et al. 1988

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Five isolates of Pseudomonas aeruginosa (CD2, CD3, CD4, CD5, and CD10) from a patient with cystic fibrosis were examined with regard to several genotypic and phenotypic characteristics to determine whether the patient was colonized with one or several distinct strains. Isolates CD2, CD3, and CD4 were obtained from a single sputum sample, and CD5 and CD10 were obtained 1 and 2 years later, respectively. On the basis of colonial morphology, serotyping, and antibiograms, the five isolates appeared to be different strains. However, Southern blot analysis with a 1.2-kilobase DNA probe containing the P. aeruginosa PAK pilin gene indicated that all five strains were identical at that genetic locus. The pilin genes of the five isolates were cloned and sequenced at the nucleotide level and found to be identical. Southern blot analysis with a probe from a separate region of the P. aeruginosa chromosome, a 741-base-pair PstI-NruI DNA fragment adjacent to the exotoxin A gene, also revealed genetic identity among these five clinical isolates. On this basis, it was concluded that this patient was colonized with a single strain of P. aeruginosa and that the strain had remained genetically stable over a period of 2 years. The predicted pilin sequence of the CD isolates was almost identical to that of strain PA103 (97% homology) and serologically related to PAO pilin, with which it shared 80% homology. No immunological cross-reactivity was detected between the CD and PAK pilins, which shared the least homology (62%) among the four pilins considered in this study. Although all five CD isolates contained identical pilin genes, three had acquired mutations which prevented normal expression of the pilus system. CD3 was a putative regulatory mutant which was unable to produce normal amounts of pilin, and CD4 and CD10 were putative assembly mutants which produced normal amounts of pilin but were unable to assemble the pilin subunit into intact pili.

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“…Epidemiologic typing of strains of Pseudomonas aeruginosa can be done by a variety of techniques, including biotyping (7,27), serologic typing (9,27,29), bacteriophage typing (5,6,14,16), pyocin typing (3,8,14,16,20,25,30), and antimicrobial susceptibility patterns (7,8).…”

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Improved, computer-generated system for pyocin typing of Pseudomonas aeruginosa

Schable¹,

Olson²,

Smith³

1986

J Clin Microbiol

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We applied numerical clustering algorithms to the selection of a new indicator strain set for the pyocin typing of Pseudomonas aeruginosa. The new indicator set is composed of selected indicator strains from the sets described in 1966 by Gillies and Govan (J. Pathol. Bacteriol. 91:339-345) and in 1974 by Jones, Zakanycz, Thomas, and Farmer (Appl. Microbiol. 27:400-406) and is designated the G-F set. This indicator set consists of 14 indicator strains which typed 99.5% of 114 test cultures, has a high degree of discrimination (10 patterns encompass 50% of the test strains), and provides 62.3% reproducibility of the same typing pattern in duplicate tests done on different days. The G-F set of indicator strains provides slightly higher percentages of typable cultures than either of the other two sets, has greater discriminatory capability, and is more reproducible than they are. We recommend that the G-F set of indicator strains be used instead of the two other sets for pyocin typing of P. aeruginosa. We also tested a recently described overlay procedure for pyocin testing of P. aeruginosa and found it to be superior to previous methods in that it is easier to perform, it provides answers in only 24 h instead of 48 h, and it can be used to type mucoid strains (which previous techniques could not readily do). Thus, the application of numerical clustering algorithms and use of a revised typing procedure have produced an improved system for pyocin typing of P. aeruginosa. Similar procedures may be applicable to other typing systems.

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Nursery Outbreak of Pseudomonas aeruginosa: Epidemiological Conclusions from Five Different Typing Methods

Cited by 21 publications

References 11 publications

Pyocin Typing of Pseudomonas aeruginosa: a Simplified Method

Pyocin Typing of Pseudomonas aeruginosa: a Simplified Method

Serial isolates of Pseudomonas aeruginosa from a cystic fibrosis patient have identical pilin sequences

Improved, computer-generated system for pyocin typing of Pseudomonas aeruginosa

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