Slide 1

Pseudomonas

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General CharacteristicsRod-shapedGram-NegativeOne or more polar flagellaStrictly aerobicStraight or curveNon-Spore Forming

One or more polarflagella, providingmotilityNon spore forming-2

Pseudomonas fluorescens

P. aeruginosacolonies on anagar platePseudomonas aeruginosa

ClassificationPseudomonas:A genus of Gram-negative aerobic gammaproteobacteriaFamily ofPseudomonadaceae

Ubiquitous-everywhere present5

Classification historywas first classified at the end of 19th century by Walter MigulaEtymology :from Greek word pseudes means false and monas means a single unit, which can mean false unit .

The etymology of the name was not specified at the time and first appeared in the 7th edition ofBergey's manual(the main authority in bacterial nomenclature) asGreekpseudes ()"false" and-monas( / )"a single unit", which can mean false unit; however, it is also possible that Migula intended it as falseMonas, a nanoflagellate protist[5](subsequently, the term "monad" was used in the early history of microbiology to denote unicellular organisms)6

Ecologycan be found in soil, marshes, coastal marine habitats, and plant and animal tissuecan tolerate a variety of physical conditionsPsychotropic: grows best at refrigerator temperature (4C)

As a result of their metabolic diversity, ability to grow at low temperatures, and ubiquitous nature, manyPseudomonasspp. can cause food spoilage.Psychotropic- responsible for the spoilage of milk even after the process of pasteurization, 7

simple carbon source such as soapresidue or cap liner-adhesivesincludeantiseptics, such as quaternaryammoniumcompounds, andbottledmineral waterEcology (cont.)

Spectrum 8

Pseudomonas aeruginosa Actively motileNonspore- formingOxidase- positive bacillus"epitome" of opportunistic pathogens

Oxidase-positive : absence of gas formation from glucose

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second-most-common infection in hospitalized patientsmildly pathogenic; almost never infects uncompromised tissues but infect practically any type of tissue if that tissue has some type of compromised defensesmost common pathogen isolated from patients who have been hospitalized longer than one weekClinical relevance

mildly pathogenic; almost never infects uncompromised tissues but infect practically any type of tissue if that tissue has some type of compromised defenses

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Common in patients with:Nosocomial InfectionsSinus infections; bronchopneumoniaUrinary Tract Infection (UTI)Burns and wound infectionsCystic Fibrosis

Clinical relevance cont

Nosocomial InfectionsHospital acquired infections

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Sinus infections; bronchopneumoniaSource: equipments that are hard to clean and sterilize such as face mask, certain kinds of humid rubber tubing nebulizer, and parts of intermittent positive- pressure breathing machinesClinical relevance cont

Urinary Tract InfectionSources: urinary cathetersThus it is advisable to discontinue the useBurns and wound infectionsBurnsP. aeruginosa usually grow aerobically in burned area.

Clinical relevance cont

They can produce exotoxins such as cystotoxins and necrotoxins , and neurotoxinsPrevention: Victim must be treated in an aseptic environmentUse of antimicrobial topical agents(e.g., silver sulfadiazine)Clinical relevance cont

They can produce exotoxins such as cystotoxins and necrotoxins that damages cells and tissues neurotoxins which affect the nervous system and may ultimately cause death

Prevention: Victim must be treated in an aseptic environment which the health personnel are gloved, gowned and masked.

The burn may be left open to the air, to speed the healing or covered with artificial skin or film to reduce contamination and loss of fluid. Some antimicrobial topical agents(e.g., silver sulfadiazine)may use to reduce the posibility of infections during the prolonged healing period.

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Wounds and Surgical infectionsP. aeruginosa from soil and feces is notorious for causing deep, antibiotic- resistant infections.Secretes enzymes which enable them to invade the blood and lymph

Clinical relevance cont

Prevention :Any trauma injury must be opened and thoroughly cleansed to remove debris and inhibit the growth of microbes; then it is usually covered lightly to prevent further contamination

Clinical relevance cont

Cystic FibrosisP. aeruginosa have a predilection for pulmonary colonization in patients with cystic fibrosis They colonizes respiratory tract (but rarely being found in sputum otherwise) persist , and tend to correlate with unfavorable prognosis Clinical relevance cont

Gram- negativeMotileNonpigmented bacillusPseudomonas pseudomallei

Pseudomonas pseudomallei causes meliodosis an uncommon tropical disease Its pulmonary manifestations are easily confused with those of tuberculosisMay be septicemia with wide lesions over the body Nicknamed Vietnamese time bomb

Clinical relevance

The organisms presumably enter the body by way of the mouth and nose or through open woundsGrowth of bacilli is wrinkled and crinkly in cultures with a typical odor. A hemagglutination test is available for diagnostic studyClinical relevance cont

mostPseudomonas spp.are naturally resistant to penicillinand the majority of relatedbeta-lactam antibiotics number are sensitive topiperacillin,imipenem,ticarcillin, orciprofloxacinAntibiotic resistance of Pseudomonas

This ability to thrive in harsh conditions is a result of their hardycell wall that contains porinsTheir resistance to most antibiotics is attributed toefflux pumps

Antibiotic resistance of Pseudomonas

Their resistance to most antibiotics is attributed toefflux pumps, which pump out some antibiotics before the antibiotics are able to act.

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Aeromonas

Gram-negativefacultative anaerobic rodmorphologically resembles members of the familyEnterobacteriaceaebeta-hemolytic on blood agar oxidase positive

Characteristics

Aeromonas hydophila

Greeknounaer, aeros which means air, gas and monas which means unit, monadAeromonas, gas(-producing) monadThey group with the gamma subclass of the ProteobacteriaEtymology

Two major diseases associated withAeromonasaregastroenteritisand wound infections, with or withoutbacteremiaAlthough some potential virulence factors (e.g.endotoxins,hemolysins,enterotoxins, adherence factors) have been identified, their precise role is unknown.

Clinical relevance

Aeromonasspecies cause:opportunistic systemic disease inimmunocompromisedpatientsdiarrheal disease in otherwise healthy individuals, andwound infections

Clinical relevance cont

Gastroenteritisin children is usually an acute, severe illnesswhereas that in adults tends to be chronic diarrheaClinical relevance cont

Aeromonasgastroenteritis resemblesshigellosiswith blood and leukocytes in the stoolAcute diarrheal disease is self limitedand only supportive care is indicated in affected patients

Clinical relevance cont

Shigellosis, also known as bacillary dysentery or Marlow Syndrome, in its most severe manifestation, is a foodborne illness caused by infection by bacteria of the genus Shigella30

Antimicrobial therapynecessary for patients with chronic diarrheal disease or systemic infectionAeromonasspecies are resistant topenicillins, mostcephalosporins, anderythromycinClinical relevance cont