Metallic Sheen in Pseudomonas aeruginosa

The production of autoplaques in clinical strains of Pseudomonas aeruginosa is very frequent andcauses considerable difficulties in work with these cultures, especially during their evaluation. There are optimum media for the demonstration of this type of autolysis. We have succeeded in the isolation of stable AP⁺ and AP^- cultures. Under the effect of passages and different media, the majority of cultures changed the irability of autolysis. Hospitals, waste-baskets, sinks, etc. represent reservoirs of AP⁺ strains of P. aeruginosa. In older cultures, cells surviving within the autoplaques may be isolated more easily than those from a culture of the same age but without autolysis. The protective effect of autolysis on some P. aeruginosa cells cannot be excluded.

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“…This was also shown by other authors [4,11,13]. No correlation between type of disease and AP pro duction was observed.…”

Section: Discussionsupporting

confidence: 76%

Importance and Evaluation of Autoplaques in Clinical Strains of <i>Pseudomonas aeruginosa</i>

Pillich¹,

Kazdová²,

Pulverer³

1974

Pathobiology

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“…2A; Luján et al., 2007). P. aeruginosa isolates not characterized by DNA sequencing, especially spontaneous mutants that emerge in vitro , may carry a lasR mutation whenever their phenotypes include absence of the LasB protease (elastase) or reduced total protease, absence of the LasI‐generated signal, the ability to grow well with phenylalanine, or large colony size together with colony iridescence and metallic sheen (Hadley, 1924; Wahba, 1964; Zierdt and Schmidt, 1964; Stanier et al ., 1966; Janda et al ., 1982; Sheehan et al ., 1982; Häussler et al ., 1999; Schaber et al ., 2004; Zhu et al ., 2004; Hoffmann et al ., 2005; Lee et al ., 2005; Pirnay et al ., 2005; Luján et al ., 2007).…”

Section: Discussionmentioning

confidence: 99%

“…Photographs were taken after incubation overnight at 37°C followed by 3 days at 22°C. and metallic sheen (Hadley, 1924;Wahba, 1964;Zierdt and Schmidt, 1964;Stanier et al, 1966;Janda et al, 1982;Sheehan et al, 1982;Häussler et al, 1999;Schaber et al, 2004;Zhu et al, 2004;Hoffmann et al, 2005;Lee et al, 2005;Pirnay et al, 2005;Luján et al, 2007).…”

Section: Pseudomonas Aeruginosa Phenotypic and Genotypic Diversitymentioning

confidence: 99%

Growth phenotypes of Pseudomonas aeruginosa lasR mutants adapted to the airways of cystic fibrosis patients

D’Argenio

Hoffman

et al. 2007

Molecular Microbiology

326

364

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SummaryThe opportunistic pathogen Pseudomonas aeruginosa undergoes genetic change during chronic airway infection of cystic fibrosis (CF) patients. One common change is a mutation inactivating lasR, which encodes a transcriptional regulator that responds to a homoserine lactone signal to activate expression of acute virulence factors. Colonies of lasR mutants visibly accumulated the iridescent intercellular signal 4-hydroxy-2-heptylquinoline. Using this colony phenotype, we identified P. aeruginosa lasR mutants that emerged in the airway of a CF patient early during chronic infection, and during growth in the laboratory on a rich medium. The lasR loss-of-function mutations in these strains conferred a growth advantage with particular carbon and nitrogen sources, including amino acids, in part due to increased expression of the catabolic pathway regulator CbrB. This growth phenotype could contribute to selection of lasR mutants both on rich medium and within the CF airway, supporting a key role for bacterial metabolic adaptation during chronic infection. Inactivation of lasR also resulted in increased b-lactamase activity that increased tolerance to ceftazidime, a widely used b-lactam antibiotic. Loss of LasR function may represent a marker of an early stage in chronic infection of the CF airway with clinical implications for antibiotic resistance and disease progression.

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Autolytic nature of iridescent lysis inPseudomonas aeruginosa

Zierdt

1971

Antonie van Leeuwenhoek

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Metallic Sheen in Pseudomonas aeruginosa

Cited by 4 publications

References 3 publications

Importance and Evaluation of Autoplaques in Clinical Strains of <i>Pseudomonas aeruginosa</i>

Importance and Evaluation of Autoplaques in Clinical Strains of <i>Pseudomonas aeruginosa</i>

Growth phenotypes of Pseudomonas aeruginosa lasR mutants adapted to the airways of cystic fibrosis patients

Autolytic nature of iridescent lysis inPseudomonas aeruginosa

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