Pseudomonas family Pseudomonadaceae Gramnegative rods motile chemoheterotrophs respiratory metabolis

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Pseudomonas family Pseudomonadaceae Gram-negativ
e rods motile chemoheterotrophs
respiratory metabolism, O2 required may use
NO3- - anaerobic respiration use many
organics as a source of C and energy metabolical
ly very diverse catalase positive
oxidase positive complex group or organisms
classification complex some species closer
to other families
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Species distinction production of
poly-ß-hydroxybutyrate production of pigments
pyocyanin fluorescein glucose
utilization pathogenicity more.. Genetics of
interest because of wide distribution of
biological and medical importance of metabolic
versatility undergo conjugation and
transduction plasmids several - resistance
metabolic diversity many lysogenic strains
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Bacteriocins proteins which kill other bacteria
- role?? Antibiotic resistance enzymes to
inactivate antibiotics use for carbon,
nitrogen, and energy
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Pseudomonas mallei - glandersPseudomonas
pseudomallei - melioidosis same? very similar
Glanders highly contagious, often
fatal horses, donkeys mules common host
transmissible to humans affects skin, lungs,
nasal membranes lumps or nodules appear
lumps enlarge and rupture bacteria-laden pus
released, disseminate animals must be destroyed

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Meliodiosis not usually in humans, but can be
fatal acute, pneumonia-like symptoms chronic
abcesses anywhere in/on body osteomyelitis
common toxins lethal factor with
anticoagulant activity skin necrotizing
agent (protease)
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Pseudomonas maltophilia 2nd most frequent
clinical isolate Pseudomonas cepacia also
important pathogen
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Pseudomonas aeruginosa most common pathogen,
opportunist compromised host most
susceptible can colonize skin, but cant
invade course of disease depends on location of
infection and host defenses antibiotic
therapy aided by early identification
Virulence factors pilus and adhesins neuriminida
se - removes carbohydrate enhances pilus
binding elastase - lung damage elastin is
30 of lung protein elastin also in blood
vessels elastase active on other proteins
also
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Virulence factors protease (major in corneal
damage) alginate - carbohydrate polymer
produced only in lung prevents
phagocytosis pigments pyocyanin - damages
endothelial tissue converts O2 to
O2- phospholipase and rhamnolipid destroy
surfactant and membranes in lung enhance
tissue invasion Exotoxin A protein
synthesis inhibitor
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Wound infections bacteria attach via pilus
aided by neuriminidase tissue damage follows
protease and phospholipase may go systemic -
septic shock LD50 for non-burn patient
108 burn patient, 30 Cystic fibrosis bind to
epithelium in upper respiratory tract move to
lung ciliated epithelium impaired in CF
patients produce alginate in lung impedes
phagocytosis lung tissue damage bacterial
enzymes, immune response (inflammation) systemic
only if defenses impaired
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Pseudomonas infections Nosocomial infections
UTI (12), respiratory (16), dermatitis,
bacteremia (10) 4/1000 discharges have a
Pseudomonas infection 10 of all nosocomial
infections Antibiotic resistance resistant to
most antibiotics most effective
fluoroquinolones, amikacin, gentamycin,
newer ß-lactam antibiotics (imipenem) (many
antibiotics bind LPS in lung, LPS changed so
antibiotics dont bind) Problems grows in
very dilute solutions grows in many
antiseptic/disinfectant solutions grows in hot
tubs, water baths
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Listeria monocytogenes Gram-positive short
rod facultative anaerobe catalase
positive motile, at 20-25C grow at
refrigerator temperatures! found in soil, water,
sewage, domestic animals 5-10 of population may
be carriers found on/in foods fresh vegetables,
shrimp milk milk products serious
pathogen, esp. immunocompromised
pregnant women (crosses the placenta)
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Virulence factors adhesins - sugar on surface
binds to tissues internalin - surface protein
promotes invasion into eukaryotic
cell actin mobilizer - enhances polymerization
moves bacteria around the cell listeriolysin
(LLO) - lysin (will lyse RBC) releases
bacteria from vesicle in phagocyte
phospholipase C - damage cell membranes
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Listeriosis bacteria in food Outbreak 1 34
perinatal infections 9 stillbirths 23
infected infants 1/3 nearly died 2
healthy infants 77 non-pregnant adult
infections 30 died Coleslaw prepared with
cabbage from farmer who had 2 sheep die of
listeriosis. Fertilized fields with sheep
manure
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Outbreak 2 142 people with symptoms
93 perinatal 30 stillborn or died shortly after
birth 49 adults 48 immunocompromised 18
died suspect pasteurization equipment failed
raw milk mixed with pasteurized cheese
contaminated
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In 1985, an outbreak of Listeriosis, due to
Mexican-style cheese, led to 18 deaths and
numerous stillbirths. As a result of this
episode, FDA has been monitoring domestic and
imported cheeses and has taken numerous actions
to remove these products from the market when L.
monocytogenes is found. The Center for Disease
Control has established an epidemiological link
between consumption of raw hot dogs or under
cooked chicken in approximately 20 of the
sporadic cases under study. Source U.S.
Department of Agriculture, Food and Safety
Inspection Service, Food and Drug Administration,
Background Document, March, April 1992.
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Sequellae bacteria bind and are
internalized bacteria escape to cytoplasm
multiply rapidly bacteria spread from cell to
cell from macrophages to liver cells
multiply there cell mediated response kills
infected cells cytotoxic T cells and
natural killer cells bacteria released
bacteria attacked by activated macrophages which
can kill the bacteria bacteria may
cross placental barrier infect fetus In healthy
adult mild flu-like symptoms maybe diarrhea and
abdominal discomfort many asymptomatic
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The Centers for Disease Control and Prevention (
CDC) estimates that 2,500 people become seriously
ill with listeriosis each year in the United
States. Of these, one in five die from the
disease. Listeriosis can be particularly
dangerous for pregnant women and their unborn
babies. Foodborne illness caused by Listeria in
pregnant women can result in premature delivery,
miscarriage, fetal death, and severe illness or
death of a newborn from the infection.
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Treatment antibiotics work well, if diagnosed
early Prevention avoid soft cheeses, raw
milk cook meats, esp. processed meats (hot
dogs) use caution with deli meats/cold
cuts reheat leftovers to high enough
temperature (bacteria grow in
refrigerator)