Incidence of common pyocin types of Pseudomonas aeruginosa from patients with cystic fibrosis and chronic airways diseases

Tredgett, M. W.; Doherty, C.; Govan, John R. W.

doi:10.1099/00222615-32-3-169

Cited by 14 publications

(7 citation statements)

References 12 publications

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“…Our genetic analysis suggests that this pattern arises because isolates from later infections carry fewer pyocin genes (figure 2). This pattern could occur through strains losing pyocin genes overtime, or through strain competition, with more competitive strains producing less pyocins [26][27][28][29][30]. Our results suggest the latter with more competitive strains producing fewer pyocins (figure 2) rather than pyocin genes being lost from strains during infection.…”

Section: (A) Bacteriocins and Strain Dominancementioning

confidence: 69%

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Bacteriocin-mediated competition in cystic fibrosis lung infections

et al. 2015

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Bacteriocins are toxins produced by bacteria to kill competitors of the same species. Theory and laboratory experiments suggest that bacteriocin production and immunity play a key role in the competitive dynamics of bacterial strains. The extent to which this is the case in natural populations, especially human pathogens, remains to be tested. We examined the role of bacteriocins in competition using Pseudomonas aeruginosa strains infecting lungs of humans with cystic fibrosis (CF). We assessed the ability of different strains to kill each other using phenotypic assays, and sequenced their genomes to determine what bacteriocins ( pyocins) they carry. We found that (i) isolates from later infection stages inhibited earlier infecting strains less, but were more inhibited by pyocins produced by earlier infecting strains and carried fewer pyocin types; (ii) this difference between early and late infections appears to be caused by a difference in pyocin diversity between competing genotypes and not by loss of pyocin genes within a lineage over time; (iii) pyocin inhibition does not explain why certain strains outcompete others within lung infections; (iv) strains frequently carry the pyocin-killing gene, but not the immunity gene, suggesting resistance occurs via other unknown mechanisms. Our results show that, in contrast to patterns observed in experimental studies, pyocin production does not appear to have a major influence on strain competition during CF lung infections.

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Section: (A) Bacteriocins and Strain Dominancementioning

confidence: 69%

“…Why do more dominant strains which cause chronic infections carry a lower diversity of pyocins (figure 2; [29])? A number of possible selective forces, which are not mutually exclusive, may be involved.…”

Section: (A) Bacteriocins and Strain Dominancementioning

confidence: 99%

Bacteriocin-mediated competition in cystic fibrosis lung infections

et al. 2015

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“…The existence of subpopulations that may have greater potential to colonize or infect the pulmonary tract of CF patients and favour other chronic obstructive airway diseases was suggested previously by an analysis of the incidence of common pyocin types (Tredgett et al, 1990).…”

Section: Discussionmentioning

confidence: 91%

Genetic features of Pseudomonas aeruginosa isolates from cystic fibrosis patients compared with those of isolates from other origins

Lanotte¹,

Watt²,

Mereghetti³

et al. 2004

Journal of Medical Microbiology

129

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In order to improve our understanding of the colonization of the pulmonary tract of cystic fibrosis (CF) patients by Pseudomonas aeruginosa, 162 isolates from five different ecological origins were studied. The genetic features of each isolate were determined by random amplification of polymorphic DNA (RAPD) and by searching for eight virulence genes (six known virulence genes, algD, lasB, toxA, plcH, plcN and exoS, and two genes encoding putative neuraminidases, nan1 and nan2). Five RAPD groups were identified. Most of the CF isolates were distributed equally in three of these groups (RA, RB and RC). The CF isolates in RB were related to isolates from a wide variety of origins. The CF isolates in RA were related to a population composed of 65 % of the non-CF isolates from pulmonary tract infections. RC was mainly composed of CF isolates that were related to 30 % of isolates from plants. All genes except exoS and nan1 were present in all isolates. The exoS and nan1 virulence factor genes were most prevalent in CF isolates. exoS, which encodes exoenzyme S, was present in 94 % of CF isolates but also in 80 % of non-CF isolates from pulmonary tract infections. nan1, which encodes a putative neuraminidase, was found in 82 . 5 % of the isolates from group RC, which was composed largely of CF isolates. In conclusion, three major genogroups of P. aeruginosa isolates, each of which exhibits peculiar genetic features, are able to colonize CF patients. This may have different consequences on the outcome of pulmonary disease.

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“…A further explanation of the predilection of the 6.1-4.1-7.8 genotype for the CF lung may be that this genotype may outcompete other genotypes within the lung environment. It has been hypothesized that the high incidence of uncommon pyocin types may be related to an enhanced ability of these P. aeruginosa pyocin types to colonize the lung (26). One such uncommon pyocin type, 9ng(S7), has been correlated with a persistent genotype isolated from four unrelated patients.…”

Section: Discussionmentioning

confidence: 99%

Heterogeneity, persistence, and distribution of Pseudomonas aeruginosa genotypes in cystic fibrosis patients

et al. 1991

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A collection of 222 isolates of Pseudomonas aeruginosa was obtained from the respiratory tract of 16 patients with cystic fibrosis over a 4to 9-month period. Fourteen of these patients were unrelated, while the remaining two were siblings. Isolates were typed by conventional pyocin typing and also by the use of a DNA probe containing 741 bp immediately upstream of the exotoxin A structural gene and the initial 732 bp of the exotoxin A structural gene. By pyocin typing, 69% (11 of 16) of the patients were shown to harbor a single type that persisted in the lung throughout the study. By genotyping (DNA probe typing), all but three patients (13 of 16, 81%) harbored a single persistent genotype in their lungs. Six patients other than the sibling pair (6 of 14, 43%) shared a common genotype in their lungs as judged by DNA probing, and the pyocin type of these isolates was also identical. In four of these six patients, the shared genotype was also the persistent genotype. The sibling pair studied also carried a common genotype in their lungs as indicated by DNA probing, even though the pyocin type of these isolates varied. Results presented suggest that the majority of patients harbor a persistent strain in their lungs and that cross-colonization may occur. Pseudomonas aeruginosa is the predominant bacterium associated with pulmonary infection in cystic fibrosis (CF) patients (6, 29). The organism persists in the airways of CF patients despite intensive antibiotic therapy and contributes to pulmonary failure, which is the major cause of morbidity and mortality in CF patients (9). Strains of P. aeruginosa colonizing the lung in CF are unique in their sensitivity to serum (6, 16, 24), presence of rough outer membrane lipopolysaccharide (5), ability to polyagglutinate in 0 antisera, and tendency to produce alginate exopolysaccharide. Understanding the epidemiology of P. aeruginosa colonization of the CF respiratory tract has been hampered due to the predominance of polyagglutinable or nontypeable strains of P. aeruginosa from CF in conventional 0-antigen serotyping reactions (13). Other conventional typing methods such as phage typing and pyocin typing have poor discriminative powers (18) or poor reproducibility (20), respectively. However, the DNA probe to the upstream region of the exotoxin A gene developed by Vasil et al. (27) has been shown to give good discrimination and reproducibility when used to type P. aeruginosa of CF origin (12). A probe similar to that used by Ogle et al. (12) was used in combination with pyocin typing in the present study. Our results confirm earlier studies (8, 12, 14, 23, 28) that suggest carriage of a persistent genotype within the lungs of CF patients. This study also presents results that suggest that cross-or coinfection may occur in nonrelated patients. MATERIALS AND METHODS Patient group. Sixteen children attending the CF clinic, Royal Children's Hospital, Brisbane, Australia, and ranging in age from 6 to 19 years were studied. Sputum specimens were collected from the patients at hom...

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Incidence of common pyocin types of Pseudomonas aeruginosa from patients with cystic fibrosis and chronic airways diseases

Cited by 14 publications

References 12 publications

Bacteriocin-mediated competition in cystic fibrosis lung infections

Bacteriocin-mediated competition in cystic fibrosis lung infections

Genetic features of Pseudomonas aeruginosa isolates from cystic fibrosis patients compared with those of isolates from other origins

Heterogeneity, persistence, and distribution of Pseudomonas aeruginosa genotypes in cystic fibrosis patients

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