Pseudomonas /Pseu·do·mo·nas/ (-mo´nas) a genus of gram-negative, aerobic bacteria, some species of which are
pathogenic for plants and vertebrates. P. aerugino´sa produces the blue-green pigment pyocyanin, which gives the
color to "blue pus" and causes various human diseases; P. acido´vorans, P. alcali´genes, P. fluores´cens, P. picket´tii,
P. pseudoalcali´genes, P. pu´tida, P. putrefa´ciens, P. stut´zeri, and P. vesicula´ris are opportunistic pathogens.

Thorax. 2003 June; 58(6): 525–527.
Identification of airborne dissemination of epidemic multiresistant strains of Pseudomonas aeruginosa at a
CF centre during a cross infection outbreak
A Jones, J Govan, C Doherty, M Dodd, B Isalska, T Stanbridge, and A Webb
Conclusions: Aerosol dissemination may be the most important factor in patient-to-patient spread of epidemic strains of
P aeruginosa during recent cross infection outbreaks at adult CF centres.

PSEUDOMONAS:  These bacteria are resistant to most antibiotics and they are capable of surviving in conditions that
few other organisms can tolerate. These pathogens colonize the lungs of cystic fibrosis patients, increasing the mortality
rate of individuals with the disease. Infection can occur at many sites and can lead to urinary tract infections, sepsis,
pneumonia, pharyngitis, and a lot of other problems. Pseudomonas aeruginosa;  pathogenicity involves several
toxins and chemicals which the bacterium secretes upon infection. The lipopolysaccharide layer helps the cell adhere to
host tissues and prevents leukocytes from ingesting and lysing the organism. Lipases and exotoxins then procede to
destroy host cell tissue which then leads to the complications associated with infection. Burkholderia (Pseudomonas)
cepacia is an opportunistic pathogen of cystic fibrosis patients. Stenotrophomonas maltophila (formerly known as
Xanthomonas maltophila) is very similar to the Pseudomonads. S. maltophila also harbors significant resistance to
many antibiotics considered effective for treating Pseudomonas infections

Appl Environ Microbiol. 1989 October; 55(10): 2627-2634

Survival of Pseudomonas putida UWC1 containing cloned catabolic genes in a model activated-sludge unit.
N C McClure, A J Weightman and J C Fry
School of Pure and Applied Biology, University of Wales College of Cardiff.


The possibility of the accidental or deliberate release of genetically engineered microorganisms into the environment
has accentuated the need to study their survival in, and effect on, natural habitats. In this study, Pseudomonas putida
UWC1 harboring a non-self-transmissible plasmid, pD10, encoding the breakdown of 3-chlorobenzoate was shown to
survive in a fully functioning laboratory-scale activated-sludge unit (ASU) for more than 8 weeks. The ASU maintained a
healthy, diverse protozoal population throughout the experiment, and the introduced strain did not adversely affect the
functioning of the unit. Although plasmid pD10 was stably maintained in the host bacterium, the introduced strain did not
enhance the degradation of 3-chlorobenzoate in the ASU. When reisolated from the ASU, derivatives of strain UWC1
(pD10) were identified which were able to transfer plasmid pD10 to a recipient strain, P. putida PaW340, indicating the in
situ transfer of mobilizing plasmids from the indigenous population to the introduced strain. Results from plate filter
matings showed that bacteria present in the activated-sludge population could act as recipients for plasmid pD10 and
actively expressed genes carried on the plasmid. Some of these activated-sludge transconjugants gave higher rates of
3-chlorobenzoate breakdown than did strain UWC1(pD10) in batch culture.

Pseudomonas putrefaciens, a strongly H2S-producing pseudomonad, was isolated from 10 human infections over a
two-year period. In one patient the organism was repeatedly isolated from a phlegmone developing in the depth of a
varicose leg ulcer. This is the first report on the occurrence of Ps. putrefaciens in humans outside the USA and the first
to provide the detailed account of a clinical observation where the opportunistic pathogenic role of this unfamiliar
organism has been sufficiently documented. Data are presented on the bacteriological properties and on the antibiotic
sensitivity of Ps. putrefaciens.

Advanced Drug Delivery Reviews
Volume 54, Issue 11, 5 December 2002, Pages 1425-1443
Current concepts on the Pathophysiology and Drug Development in Cystic Fibrosis
Copyright © 2002 Elsevier Science B.V. All rights reserved.

Anaerobic metabolism and quorum sensing by Pseudomonas aeruginosa biofilms in chronically infected
cystic fibrosis airways: rethinking antibiotic treatment strategies and drug targets

Daniel J. Hassett, , a, John Cuppolettib, Bruce Trapnellc, Sergei V. Lymard, John J. Rowee, Sang Sun Yoona, George
M. Hilliardb, Kislay Parvatiyara, Moneesha C. Kamania, Daniel J. Wozniakf, Sung-Hei Hwanga, Timothy R. McDermottg
and Urs A. Ochsnerh  a Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati
College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267-0524, USA  b Department of Molecular and Cellular
Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA  c Division of Pulmonary Biology,
Children’s Hospital Medical Center, Cincinnati, OH 45229-3039, USA  d Brookhaven National Laboratory, Upton, NY
11973-5000, USA  e Department of Biology, University of Dayton, Dayton, OH 45469, USA  f Department of Microbiology
and Immunology, Wake Forest University, Winston-Salem, NC 27157, USA  g Center for Biofilm Engineering and
Department of Land Resources, Montana State University, Bozeman, MT 59717, USA  h Department of Microbiology,
University of Colorado Health Sciences, Denver, CO 80262, USA   Received 26 March 2002;  accepted 21 August 2002.
; Available online 16 November 2002.  

Recent evidence indicates that Pseudomonas aeruginosa residing as biofilms in airway mucus of cystic fibrosis (CF)
patients is undergoing anaerobic metabolism, a form of growth requiring gene products that are not utilized during
aerobic growth. The outer membrane protein, OprF, and the rhl quorum sensing circuit are two previously unrecognized
cellular factors that are required for optimal anaerobic biofilm viability. Without OprF, bacteria grow extremely poorly
because they lack nitrite reductase activity while lacking rhlR or rhlI forces bacteria to undergo metabolic suicide by
overproduction of nitric oxide. Furthermore, anaerobic growth favors maintenance of the mucoid, alginate-
overproducing phenotype. Thus, with increasing age of CF patients, mucoid populations predominate, indicating that
anaerobic bacteria reside in the inspissated airway mucus. Because many frontline antibiotics used in the treatment of
CF airway disease are either ineffective or show reduced efficacy during anaerobic conditions, we propose development
of new drugs to combat anaerobic metabolism by P. aeruginosa for more effective treatment of chronic CF lung
Figure 9. (click image to zoom) By day 10,
overlying skin succumbed to induration,
gangrene, and necrosis. Infection continued
to progress, and patient expired. Reprinted
from Am J Med (1988;85:490-494), Copyright
© 1988, Excerpta Medica, Inc.[6