Pseudomonas an update

10,576 views

Published on

Pseudomonas an update

Published in: Health & Medicine
5 Comments
35 Likes
Statistics
Notes
No Downloads
Views
Total views
10,576
On SlideShare
0
From Embeds
0
Number of Embeds
13
Actions
Shares
0
Downloads
1,073
Comments
5
Likes
35
Embeds 0
No embeds

No notes for slide

Pseudomonas an update

  1. 1. Pseudomonas an update Dr.T.V.Rao MD Dr.T.V.Rao MD 1
  2. 2. What are Pseudomonas• Pseudomonads are aerobic, saprophytic and innately resistant bacteria causing opportunist infections in man, animals, plants and insects. The most important pseudomonad species responsible for human infections are Pseudomonas aeruginosa, Burkholderia pseudo mallei and members of the Burkholderia cepacia complex. Dr.T.V.Rao MD 2
  3. 3. Pseudomonas• A large group of aerobic, non sporing gram negative bacteria motile by polar flagella• Found In nature water, soil, other moist environments• Some of them are pathogenic to plants• Creation of new genera such as Burkholderia. Stenotrophomnonas Dr.T.V.Rao MD 3
  4. 4. Pseudomonas aeruginosa• Gram-negative aerobe bacteria• Commonly found in the environment – At any moist location• Common cause of nosocomial infections Dr.T.V.Rao MD 4
  5. 5. General Characteristics- Widely distributed in soil and water- Gram negative rods- Aerobic- Motile- Produce water- soluble pigments• Opportunistic pathogens Dr.T.V.Rao MD 5
  6. 6. Pseudomonas• Aerobic, opportunistic pathogen• Gram-negative bacillus• Flagellated Dr.T.V.Rao MD 6
  7. 7. Structure of Pseudomonas Dr.T.V.Rao MD 7
  8. 8. Pseudomonas aeruginosa •Morphologyslender, Gram negative bacillussize-1.5 microns-3*1.5micronsmotile by polar flagellanon capsulated though some mucoid strains may sometimes occursome are pilated Dr.T.V.Rao MD 8
  9. 9. Morphology• They are slender gram negative bacillus, 1.5 – 3 microbes x 0.5 microns• Monoflgellar ?• Non capsulated but many strains have mucoid slime layer• Isolates from Cystic fibrosis patients have abundance of extracellular polysaccharides composed of alginate polymers• Escape the defence mechanisms by loose capsule in which micro colonies of bacillus are enmeshed and protected from host defences. Dr.T.V.Rao MD 9
  10. 10. Cultural characteristicsObligate aerobeWide range of temperature 5°c- 42°c optimum 37°cOrdinary media – large, opaque, irregular, with distinctive musty, mawkish, earthy smell Dr.T.V.Rao MD 10
  11. 11. P. aeruginosa Forms round colonies with a fluorescent greenish color, sweet odor, and -hemolysis. Pyocyanin- nonfluorescent bluish pigment; pyoverdin- fluorescent greenish pigment; pyorubin, and pyomelanin Some strains have a prominent capsule (alginate).Identification of P. aeruginosa is usually based on oxidase testand its colonial morphology: b-hemolysis, the presence ofcharacteristic pigments and sweet odor, and growth at 42 oC. Dr.T.V.Rao MD 11
  12. 12. Cultural Characters• Obligate aerobe, but grow anaerobically if nitrate is available• Growth occurs at wide range of temperatures 6-42 c the optimum being 37 c• Growth on ordinary media producing large opaque irregular colonies with distinctive musty mawkish or earthy smell.• Iridescent patches with metallic sheen are seen in cultures on nutrient agar.• In broth forms dense turbidity with surface pellicle. Dr.T.V.Rao MD 12
  13. 13. Characteristics of Pseudomonas aeruginosaMotile (by single or multiple polar flagella) gram-negative rodsObligate (strict) aerobes (most strains)Oxidase (usually) and catalase positiveNonfermentative chemoheterotrophic respiratory metabolism Dr.T.V.Rao MD 13
  14. 14. Characteristics of Pseudomonas• Minimal nutritional requirements .; Many organic compounds used as C and N sources, but only a few carbohydrates by oxidative metabolism• Glucose used oxidatively• Lactose negative on MacConkey agar Dr.T.V.Rao MD 14
  15. 15. Nutrient agar- Cont..• Nutrient agar- Colonies are smooth,large,translucen t,low convex,2-4mm in diameter. Produce sweetish aromatic odor Greenish blue pigment diffuses Dr.T.V.Rao MD 15
  16. 16. Growing on• Blood agarSimilar to nutrient agarMany are haemolytic• Mac conkey agarColourless,non lactose fermenters• Cetrimide agarselective media Dr.T.V.Rao MD 16
  17. 17. Pigment ProductionSome strains produce diffusible pigments: • Pyocyanin (blue); fluorescein (yellow); pyorubin (red)P. aeruginosa produces characteristic grape-like odor and blue-green pus & coloniesBroad antibiotic resistance Dr.T.V.Rao MD 17
  18. 18. Toxins and enzymes in pseudomonas• Toxic extracellular products in culture filtrates• Exotoxin A and S• Exotoxin A acts as NADase resembling Diphtheria toxin• Proteases,elastatese hemolysins and enterotoxin• Slime layer and Biofilms MD Dr.T.V.Rao 18
  19. 19. Biochemical reactions• Oxidative and Non fermentative• Glucose is utilized oxidatively• Indole, MR and VP and H2 S tests are negative• Catalase, Oxidase, and Arginine tests are positive Dr.T.V.Rao MD 19
  20. 20. Typing and Importance• Important cause of Hospital Infections• Important for epidemiological purpose• Serotyping• Bacteriocins typing• Pyocyanin• Aeruginosa typing• Restriction endonuclease typing with pulsed gel electrophoresis Dr.T.V.Rao MD 20
  21. 21. Resistance• Killed at 55oc in on 1 hour• High resistance to chemical agents• Resistance to quaternary ammonium compounds.Chlorxylenol• Resistant to Hexachlorophenes• Grows also in antiseptic bottles• Dettol as Cetrimide as selective medium• Sensitive to acids silver salts, beta glutaraldehyde Dr.T.V.Rao MD 21
  22. 22. Major Pathogenicity• Blue pus• Causing the nosocomial infection• Suppurative otitis• Localised and generalised infections• Urinary tract infection after catheterization• Iatrogenic meningitis• Post tracheostomy pulmonary infections Dr.T.V.Rao MD 22
  23. 23. Pathogenesis and Immunity• P. aeruginosa can infect almost any external site or organ.• P. aeruginosa is invasive and toxigenic. It attaches to and colonizes the mucous membrane or skin, invade locally, and produces systemic diseases and septicemia.• P. aeruginosa is resistant to many antibiotics. It becomes dominant when more susceptible bacteria of the normal flora are suppressed. Dr.T.V.Rao MD 23
  24. 24. Clinical Presentations• Septicaemia• Endocarditis• Ecthyma gangrenous• Infantile diarrhoea• Shanghai fever• Disabling eye infections• Survive with minimal nutrients Dr.T.V.Rao MD 24
  25. 25. P. aeruginosa infections• P. aeruginosa infections are of particular concern for Cystic fibrosis patients• Burn patients• Hospitalised patients – Case mortality rate for patients infected with P. aeruginosa approaches 50% Dr.T.V.Rao MD 25
  26. 26. Pseudomonas aeruginosa an important opportunistic pathogen• Pseudomonas aeruginosa is an opportunistic pathogen, meaning that it exploits some break in the host defences to initiate an infection. In fact, Pseudomonas aeruginosa is the epitome of an opportunistic pathogen of humans. The bacterium almost never infects uncompromised tissues, yet there is hardly any tissue that it cannot infect if the tissue defences are compromised in some manner Dr.T.V.Rao MD 26
  27. 27. P. aeruginosa is an opportunistic pathogen• Extremely broad host spectrum• Hardly any infections in the normal human host• Severe immunodeficiencies and medical devices predispose the patients to P. aeruginosa infections• Broad spectrum of clinical symptoms – Urinary tract infections – Pulmonary infections – Soft tissue infections – Sepsis – Bone and joint infections – Endocarditis Dr.T.V.Rao MD 27
  28. 28. P,aeroginosa is an opportunistic pathogen• P,aeroginosa is an opportunistic pathogen. It rarely causes disease in healthy persons. In most cases of infection, the integrity of a physical barrier to infection (eg, skin, mucous membrane) is lost or an underlying immune deficiency (eg, neutropenia, immunosuppression) is present. Adding to its pathogenicity, this bacterium has minimal nutritional requirements and can tolerate a wide variety of physical conditions Dr.T.V.Rao MD 28
  29. 29. WHO are MORE SUSCEPTIBLE TO INFECTION• This bacterium is of particular concern to individuals with cystic fibrosis who are highly susceptible to pseudomonas lung infections. Pseudomonas aeruginosa is also of grave concern to cancer and burn patients as well as those people who are immunocompromised. The case fatality rate for individuals infected with Pseudomonas aeruginosa approaches 50 percent. Dr.T.V.Rao MD 29
  30. 30. Nosocomial infections• Fourth most common isolated nosocomial pathogen accounting for approx.• 10 % of all hospital acquired infections.• Patient-to-patient spread and direct patient contact with environmental reservoirs – disinfectants, – respiratory equipment, – food, – sinks, taps Dr.T.V.Rao MD 30
  31. 31. Pseudomonas prominent hospital acquired infections• It causes urinary tract infections, respiratory system infections, dermatitis, soft tissue infections, bacteraemia, bone and joint infections, gastrointestinal infections and a variety of systemic infections, particularly in patients with severe burns and in cancer and AIDS patients who are immunosuppressed.Dr.T.V.Rao MD 31
  32. 32. Virulence factorsVirulence Factors (structural components)• “Alginate”• Adherence proteins and “pili• Lipopolysaccharide (LPS)• Pyocyanin Dr.T.V.Rao MD 32
  33. 33. Infection of Equipments• Respirators• Endotracheal tubes• Can be Infected• All equipments to be sterilized Dr.T.V.Rao MD 33
  34. 34. Pseudomonas and Cystic fibrosis • Pseudomonas aeruginosa is the most frequently encountered lung pathogen in patients with cystic fibrosis (CF). Following initial, often intermittent, episodes of infection, it becomes a permanently established component of the chronically infected lung in more than 80% of patients and confers an Dr.T.V.Rao MD adverse prognosis 34
  35. 35. Pigment production • PyocyaninBluish green phenazine pigmentSoluble in chloroform and waterNot produced by other species • Pyoverdin(fluorescein)It is a greenish yellow pigmentInsoluble in chloroform but soluble in waterProduced by many other species Dr.T.V.Rao MD 35
  36. 36. Pyocyanin Pyoverdin Dr.T.V.Rao MD 36
  37. 37. Cont..• PyorubinReddish brown pigmentInsoluble in chloroform but soluble in water• pyomelaninBrown to black pigmentProduction is uncommon Dr.T.V.Rao MD 37
  38. 38. Biochemical reactionsO/F test- oxidativeCatalase- positiveOxidase-positiveNitrate reduction- positive Dr.T.V.Rao MD 38
  39. 39. Biochemical Tests• Indole test-negative• Methyl red test- negative• Vp test-negative• Citrate test-positive• Urease test-negative Dr.T.V.Rao MD 39
  40. 40. Structural Components• Adherence to host cells mediated by pili and nonpilus adhesins.• LPS (lipopolysaccharide) inhibiting antibiotic killing and suppress neutrophil and lymphocyte activity• Alginate – mucoid exopolysaccharide that forms a shiny biofilm protecting from antibodies, complement, phagocytosis, and antibiotics• Procyanin – impairs ciliary function, mediates tissue damage through production of oxgen radicals Dr.T.V.Rao MD 40
  41. 41. Patho mechanisms• Adhesion – Pile, flagella and fimbriae• Invasion – Extracellular enzymes and toxins (proteases, elastase, phospholipases, rhamnolipids, Exotoxin A)• Dissemination – Leukocidin inhibits neutrophils und leukocytes – LPS (Endotoxin)• Protection – Capsule (Alginate) Dr.T.V.Rao MD 41
  42. 42. PathogenesisVirulence Factors (toxins and enzymes):• Exotoxin A• Exoenzyme S• Endotoxins• Phospholipase C• Elastase and Alkaline Protease Dr.T.V.Rao MD 42
  43. 43. PATHOGENESIS• Important agent in causing nosocomial infections• Most common infections areUrinary tract infections following catheterizationAcute purulent meningitis following lumbar puncturePost-tracheostomy pulmonary infectionSepticemia in debilitated patients Dr.T.V.Rao MD 43
  44. 44. Mechanism Of Pathogenesis• Caused by exotoxins,proteases,elastases,haemolysins, lipases and enterotoxinsExotoxin A-lethal toxinElastases-haemorrhagic lesionsEnterotoxins-diarrhoeal diseaseSlime layer acts as a capsule and enhances virulence Dr.T.V.Rao MD 44
  45. 45. Exotoxin A• Similar in structure to Diphtheria toxin• Inhibits protein synthesis by ADP-ribosylating EF-2 (G-protein)• Causes Dermatonecrosis in burn wounds, corneal damage in ocular infections, and tissue damage in chronic pulmonary infections.• Also this toxin is immunosuppressive• ADP-ribosylates G-proteins including p21 RAS interfering with host cell growth Dr.T.V.Rao MD 45
  46. 46. Phospholipase C• Heat labile hemolysins• Breaks down lipids and lecithin causing tissue destruction• Stimulates inflammatory response Dr.T.V.Rao MD 46
  47. 47. Lactase and Alkaline Protease• Destruction of elastin-containing tissues (blood vessels, lung tissue, skin), collagen, immunoglobulins, and complement factors• Can produce hemorrhagic lesions (ecthyma gangrenous) associated with disseminated infection• Inactivation of interferon and TNF-Alpha Dr.T.V.Rao MD 47
  48. 48. Epidemiology• Ubiquitous in moist environmental sites in the hospital as well as nature• No seasonal incidence• Can transiently colonize the respiratory and GI tract of hospitalized patients• Minimal nutritional requirements and can tolerate broad temperature spectrum Dr.T.V.Rao MD 48
  49. 49. Important cause of Hospital Acquired Infection• Pseudomonas aeruginosa is an important cause of hospital-acquired infections, especially in intensive care units and in neutropenic patients. Infections range from topical to systemic and may be trivial or life- threatening. Dr.T.V.Rao MD 49
  50. 50. Clinical Disease• Pulmonary Infections• Burn Wound Infections and other skin and soft tissue infections (life threatening)• UTI’s (especially catheterized)• External Otitis (malignant OE, swimmer’s ear)• Eye Infections and corneal ulceration via contaminated contact lens cleaning fluids• Pseudomonal Endocarditis Dr.T.V.Rao MD 50
  51. 51. Pulmonary Infections• Can range from asymptomatic colonization to severe necrotizing bronchopneumonia• Colonization is seen in patients with cystic fibrosis, chronic lung disease, and neutropenia• Mucoid strains are commonly isolated from chronic pulmonary patients and are more difficult to eradicate• Predisposing conditions include previous therapy with broad spectrum abx (disrupts normal protective bacteria population and use of respiratory therapy equipment (can introduce the organism to lower airways)• Mortality rate can be as high as 70% for invasive bronchopneumonia Dr.T.V.Rao MD 51
  52. 52. Pseudomonas PNA Dr.T.V.Rao MD 52
  53. 53. Ecthyma Gangrenosum• Ecthyma gangrenosum is a well recognized cutaneous manifestation of severe, invasive infection by Pseudomonas aeruginosa that is usually seen in immunocompromised, burn patients, and other critically ill patients Dr.T.V.Rao MD 53
  54. 54. Echtyma Gangrenosum Dr.T.V.Rao MD 54
  55. 55. Malignant Otitis Externa Dr.T.V.Rao MD 55
  56. 56. Pseudomonas Keratitis and Corneal Ulceration Dr.T.V.Rao MD 56
  57. 57. Endocarditis Dr.T.V.Rao MD 57
  58. 58. Cystic fibrosis• Most common life-threatening inherited genetic disorder in the Caucasian population• Mutation in the cystic fibrosis trans membrane conductance regulator (CFTR) gene• one in every 25 carry the mutated recessive gene and more than 1 in 4000 live births suffer from CF.• Dr.T.V.Rao MD 58
  59. 59. Chronic infection of the Cystic Fibrosis lung Dr.T.V.Rao MD 59
  60. 60. Pseudomonas and urinary tract infections• Pseudomonal UTIs are usually hospital- acquired and are associated with catheterization, instrumentation, and surgery. These infections can involve the urinary tract through an ascending infection or through bacteriuic spread. In addition, these infections are a frequent source of bacteraemia. No specific characteristics distinguish this type of infection from other forms of UTI. Dr.T.V.Rao MD 60
  61. 61. Diagnosis of P.aeroginosa infection• Diagnosis of P,aeroginosa infection depends upon isolation and laboratory identification of the bacterium. It grows well on most laboratory media and commonly is isolated on blood agar or eosin- methylthionine blue agar. It is identified on the basis of its Gram morphology, inability to ferment lactose, a positive oxidase reaction, its fruity odour, and its ability to grow at 42°C. Fluorescence under ultraviolet light is helpful in early identification of P.s aeruginosa colonies. Fluorescence is also used to suggest the presence of P. aeruginosa in wounds. Dr.T.V.Rao MD 61
  62. 62. Fluorescence of Pseudomonas• Fluorescence under ultraviolet light is helpful in early identification of P.s aeruginosa colonies. Fluorescence is also used to suggest the presence of P. aeruginosa in wounds. Dr.T.V.Rao MD 62
  63. 63. Diagnosis of P. aeruginosa• Isolation and lab identification of the pathogen• P. aeruginosa grows well on most laboratory media• Identified on the basis of its: – Gram morphology, – inability to ferment lactose, – a positive oxidase reaction, – its characteristic odor, – its ability to grow at 42° C. – Fluorescence is helpful in early identification of P. aeruginosa colonies and may also help identify its presence in wounds. Dr.T.V.Rao MD 63
  64. 64. What antibiotics to use• Aminoglycosides• Gentamycin, Amikacin, Cephalosporins• Cefotaxime. Ceftazidime. Ofloxacin,• Piperacillin, Ticarcillin• Local application, colistin, polymyxin Dr.T.V.Rao MD 64
  65. 65. Treating pseudomonas infections• Combined antibiotic therapy is generally required to avoid resistance that develops rapidly when single drugs are employed. Avoid using inappropriate broad-spectrum antibiotics, which can suppress the normal flora and permit overgrowth of resistant pseudomonads. Dr.T.V.Rao MD 65
  66. 66. Treatment of P. aeruginosa infections• P. aeruginosa is frequently resistant to many commonly used antibiotics.• To archive synergy a combination of e.g. gentamicin and carbenicillin is frequently used.• No vaccines so far Dr.T.V.Rao MD 66
  67. 67. Pseudomonas aeruginosa a resistant pathogen• Pseudomonas aeruginosa is frequently resistant to many commonly used antibiotics. Although many strains are susceptible to gentamicin, tobramycin, colistin, and amikacin, resistant forms have developed. The combination of gentamicin and carbenicillin is frequently used to treat severe Pseudomonas infections. Several types of vaccines are being tested, but none is currently available for general use. Dr.T.V.Rao MD 67
  68. 68. Antibiotic Resistance• Inherently resistant to many antibiotics• Can mutate to more resistant strains during therapy• Penetration of abx highly dependent on outer membrane pores which can be altered• Production of B-lactamases• Combination of active antibiotics generally required for successful therapy Dr.T.V.Rao MD 68
  69. 69. P. aeruginosa Prevention and ControlPseudomonas spp. normally inhabit soil,water, and vegetation and can be isolatedfrom the skin, throat, and stool of healthypersons.Spread is mainly via contaminated sterileequipments and cross-contamination ofpatients by medical personnel. Dr.T.V.Rao MD 69
  70. 70. Prevention and Control• High risk population: patients receiving broad-spectrum antibiotics, with leukaemia, burns, cystic fibrosis, and immunosuppression.• Methods for control of infection are similar to those for other nosocomial pathogens. Special attention should be paid to sinks, water baths, showers, hot tubs, and other wet areas. Dr.T.V.Rao MD 70
  71. 71. BURKHOLDERIA• Although most of the presently 30 known Burkholderia species are saprophytes, B. pseudomallei, B. mallei and the B. cepacia complex are important human or animal pathogens Dr.T.V.Rao MD 71
  72. 72. Burkholderia pseudomallei• Burkholderia pseudomallei is the causative agent of melioidosis, a serious tropical infection of man and animals endemic in South-East Asia and Northern Australia Dr.T.V.Rao MD 72
  73. 73. B. pseudomallei• The environmental saprophyte B. pseudomallei causes melioidosis, a life- threatening tropical infection of man and animals in Southeast Asia and Northern Australia. In endemic areas the organism is found in soil and surface water, particularly rice paddy fields and monsoon drains. Isolation rates are highest during the rainy season and in still rather than flowing water. Dr.T.V.Rao MD 73
  74. 74. Other related organisms• A closely related species, B. mallei, causes glanders, a potentially fatal infectious disease of horses, mules and donkeys. Laboratory-acquired infection with either organism is a serious risk (hazard category 3) and both are regarded as potential bioterrorism agents. Dr.T.V.Rao MD 74
  75. 75. B. cepacia• B. cepacia, the cause of soft rot of onions, is also an important human pathogen causing life-threatening respiratory infection in immunocompromised patients, particularly those treated in intensive care or with chronic granulomatous disease. Dr.T.V.Rao MD 75
  76. 76. B.cepacia and Cystic fibrosis• In cystic fibrosis, anxiety over B. cepacia is based on the innate multiresistance of the organism to antibiotics, its transmissibility by social contact, and the risk of cepacia syndrome, an acute, fatal necrotizing pneumonia, sometimes accompanied by bacteraemia, which occurs in 20-30% of infected patients. Dr.T.V.Rao MD 76
  77. 77. Virulence factors in B.cepacia• B. cepacia complex isolates produce several putative virulence determinants, including proteases, catalases, haemolysin, exopolysaccharide, cable pili and other adhesins. In vitro the lipid A of these bacteria stimulates pro- inflammatory cytokines tenfold more than Ps. aeruginosa lipid A. Dr.T.V.Rao MD 77
  78. 78. Pathogenesis• Human infection is acquired mainly percutaneously through skin abrasions or by inhalation of contaminated particles, especially during monsoon rains. Melioidosis commonly presents as pyrexia. The clinical manifestations are protean and range from dormant subclinical infection,. Dr.T.V.Rao MD 78
  79. 79. Diagnosis• Diagnosed by the presence of specific antibodies, to acute pneumonia or chronic pulmonary infection that may resemble tuberculosis and other conditions, leading to a fulminating septicaemia with a mortality rate of 80- 90%.. Suppurative parotitis is a characteristic presentation of melioidosis in children Dr.T.V.Rao MD 79
  80. 80. Treatment• Accurate and early diagnosis, including culture of B. pseudomallei, and appropriate antibiotic therapy are key to successful management. The optimum treatment of severe melioidosis is unclear. Intravenous ceftazidime, followed by a combination of co- trimoxazole and doxycycline, is emerging as the treatment of choice. Dr.T.V.Rao MD 80
  81. 81. Treatment is a Urgent Concern• Intravenous ceftazidime, followed by a combination of co-trimoxazole and doxycycline, is emerging as the treatment of choice. Imipenem or meropenem have sometimes been effective when treatment with ceftazidime has proved unsuccessful. Prolonged treatment is necessary to avoid relapse Dr.T.V.Rao MD 81
  82. 82. • Programme Created by Dr.T.V.Rao MD for Medical and Paramedical Students in Developing World • Email • doctortvrao@gmail.com Dr.T.V.Rao MD 82

×