Development of a diagnostic test for the Midlands 1 cystic fibrosis epidemic strain of Pseudomonas aeruginosa

Abstract

In a previous study of isolates from cystic fibrosis (CF) patients in England and Wales, the Midlands 1 strain of Pseudomonas aeruginosa was identified as the second most common clone, representing 10 % of isolates and found in nearly one-third of all CF centres [Scott, F. W. & Pitt, T. L. (2004). J Med Microbiol 53, 609-615]. Using suppression subtractive hybridization, 54 sequences were identified as present in a Midlands 1 strain but were absent from strain PAO1. The distribution of 14 of these sequences amongst representatives of Midlands 1, other CF epidemic strains and unrelated P. aeruginosa CF isolates was determined using PCR assays. Using these data, a PCR-based test was developed that was specific for the Midlands 1 clone, which was confirmed using dot-blot hybridization. By applying the test to CF isolates from a CF centre in Liverpool, a Midlands 1 clone was identified. The identity was confirmed using typing by PFGE. The PCR test should facilitate a greater understanding of the distribution of the Midlands 1 strain in the UK and elsewhere.

Transmissible strains ofPseudomonas aeruginosain cystic fibrosis lung infections

“…Some genetic analysis of the Mid1 strain has been published [114]. Mid1 and LES share the same serotype (O6) and carry the more unusual pyoverdine biosynthesis and receptor genes (type III) but differ in flagellin types [114].…”

“…Mid1 and LES share the same serotype (O6) and carry the more unusual pyoverdine biosynthesis and receptor genes (type III) but differ in flagellin types [114]. On the basis of strain typing by use of an ArrayTube chip, the Mid1 strain was assigned to the same group as strains from a German intensive care unit and one strain found in a German river, and the LES belonged to the same type as an isolate from a patient with bacteraemia in a Swiss clinic [13].…”

“…For some transmissible strains, specific PCR assays have been developed, thus enabling cheap and simple screening to be carried out. For the LES, diagnostic tests were originally developed using suppression subtractive hybridisation (SSH) to identify strainspecific sequences [ strains (MES [107], Mid1 [114] and AES-1 [95]) have also been developed using a similar approach. With the rise in rapid sequencing and associated decrease in cost, it is likely that methods such as SSH will eventually be entirely superseded by sequencing and bioinformatics analysis.…”

Development and Validation of a PCR Assay To Detect the Prairie Epidemic Strain of Pseudomonas aeruginosa from Patients with Cystic Fibrosis

“…Accordingly, we sought to develop a simple PCR assay to distinguish PES from non-PES P. aeruginosa organisms for clinical and research purposes in areas where this strain is prevalent (western Canada). Similar assays have been developed for other epidemic P. aeruginosa strains, including Liverpool epidemic strain (LES), Midlands-1, Manchester, and Australia epidemic strain-1 (AUS-1), and they are used prospectively in infection control and research (1)(2)(3)(4).…”

“…ultiple epidemic strains of Pseudomonas aeruginosa have been described as infecting patients with cystic fibrosis (CF) (1)(2)(3)(4). Many of these strains are associated with a poor prognosis, manifesting as increased rates of lung function decline, exacerbation frequency, and treatment burden; decreased quality of life; and hastened progression to end-stage lung diseases (5,6).…”