Opportunistic Enterobact


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Opportunistic Enterobact

  1. 1. OPPORTUNISTIC ENTEROBACTERIACEAE Fe A. Bartolome, MD, FPASMAP Department of Microbiology Our Lady of Fatima University
  2. 2. <ul><li>commensals of the large intestines </li></ul><ul><li>infections found outside the intestines </li></ul><ul><li>can infect any tissue of the body </li></ul><ul><li>usual type of infection produced: </li></ul><ul><ul><li>UTI 4. Meningitis </li></ul></ul><ul><ul><li>Wound infection 5. Septicemia </li></ul></ul><ul><ul><li>Pneumonia 6. GI disorders </li></ul></ul>
  3. 3. <ul><li>Klebsiella-Enterobacter-Serratia Group </li></ul><ul><li>Lactose fermenters EXCEPT Serratia group </li></ul><ul><li>Give (+) Voges-Proskauer reactions  presence of acetylmethyl carbinol </li></ul><ul><li>Resistant to Ampicillin </li></ul>
  4. 4. Klebsiella <ul><li>Characteristics: </li></ul><ul><ul><li>Non-motile </li></ul></ul><ul><ul><li>Encapsulated – large polysaccharide capsule </li></ul></ul><ul><ul><li>Weak urease producer </li></ul></ul><ul><ul><li>Mucoid appearance of isolated colonies due to capsule </li></ul></ul><ul><ul><li>IMViC: - - + + TSI: A/A + gas </li></ul></ul><ul><ul><li>(+) test for lysine decarboxylase & citrate </li></ul></ul>
  5. 5. Klebsiella <ul><ul><li>Klebsiella pneumoniae </li></ul></ul><ul><ul><ul><li>Friedlander’s bacillus </li></ul></ul></ul><ul><ul><ul><li>Most commonly isolated member </li></ul></ul></ul><ul><ul><ul><li>Present in respiratory tract & feces of about 5% of normal individuals </li></ul></ul></ul><ul><ul><ul><li>Cause nosocomial or community-acquired infections </li></ul></ul></ul>
  6. 8. Klebsiella <ul><li>Klebsiella pneumoniae </li></ul><ul><ul><li>Clinical: </li></ul></ul><ul><ul><ul><li>Primary lobar pneumonia </li></ul></ul></ul><ul><ul><ul><ul><li>Individuals with underlying medical problems </li></ul></ul></ul></ul><ul><ul><ul><ul><li>At risk: alcoholics & people with compromised pulmonary function </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Extensive hemorrhagic necrotizing consolidation of lungs  (+) blood-tinged, thick, non-putrid sputum </li></ul></ul></ul></ul>
  7. 10. Klebsiella <ul><li>Klebsiella pneumoniae </li></ul><ul><ul><li>Clinical: </li></ul></ul><ul><ul><ul><li>Others: UTI, wound infection, bacteremia, meningitis, endophthalmitis </li></ul></ul></ul>
  8. 11. Klebsiella pneumoniae endophthalmitis
  9. 12. Klebsiella pneumoniae wound infection
  10. 13. Klebsiella <ul><li>Klebsiella oxytoca </li></ul><ul><ul><li>Biochemically similar to K. pneumoniae but indole (+) </li></ul></ul><ul><ul><li>Similar infection to K. pneumoniae </li></ul></ul>
  11. 14. Klebsiella <ul><li>Klebsiella ozaenae </li></ul><ul><ul><li>Fetid, progressive atrophy of mucous membranes of the nose  chronic atrophic rhinitis </li></ul></ul>
  12. 15. Klebsiella <ul><li>Klebsiella rhinoscleromatis </li></ul><ul><ul><li>Rhinoscleroma – chronic granulomatous destruction of nose and pharynx </li></ul></ul>
  13. 17. Enterobacter <ul><li>Also known as Aerobacter </li></ul><ul><li>Usually nosocomially acquired </li></ul><ul><li>Characteristics: </li></ul><ul><ul><li>Motile </li></ul></ul><ul><ul><li>Usually non-encapsulated </li></ul></ul><ul><ul><li>(-) urease production </li></ul></ul><ul><ul><li>Citrate and ornithine decarboxylase (+) </li></ul></ul><ul><ul><li>IMViC: - - + + TSI: A/A + gas </li></ul></ul>
  14. 18. Enterobacter <ul><li>Enterobacter cloacae </li></ul><ul><ul><li>Cause majority of infections </li></ul></ul><ul><ul><li>Most frequently associated with UTI </li></ul></ul><ul><li>Enterobacter aerogenes </li></ul><ul><ul><li>With small capsules </li></ul></ul><ul><ul><li>May be found free-living as well as in the intestinal tract </li></ul></ul><ul><ul><li>Cause UTI and sepsis </li></ul></ul>
  15. 20. Serratia <ul><li>Characteristics: </li></ul><ul><ul><li>Able to produce DNase, lipase and gelatinase </li></ul></ul><ul><ul><li>Resistant to Colistin and Cephalotin </li></ul></ul><ul><ul><li>Usually non-pigmented </li></ul></ul><ul><ul><li>Ferments lactose slowly </li></ul></ul>
  16. 21. Serratia <ul><li>Serratia marcescens </li></ul><ul><ul><li>Most frequently isolated </li></ul></ul><ul><ul><li>Common opportunistic pathogen </li></ul></ul><ul><ul><li>(+) production of bright red pigment (prodigiosin) </li></ul></ul>
  17. 22. Serratia <ul><li>Serratia marcescens </li></ul><ul><ul><li>Infections associated with: </li></ul></ul><ul><ul><ul><li>Invasive procedures – IV catheterization, resp. intubation & urinary tract manipulation </li></ul></ul></ul><ul><ul><ul><li>Contamination of water in respiratory therapy devices </li></ul></ul></ul><ul><ul><ul><li>Narcotics addicts </li></ul></ul></ul>
  18. 24. Serratia <ul><li>Serratia marcescens </li></ul><ul><ul><li>Diseases: </li></ul></ul><ul><ul><ul><li>Pneumonia </li></ul></ul></ul><ul><ul><ul><li>Bacteremia </li></ul></ul></ul><ul><ul><ul><li>Endocarditis </li></ul></ul></ul><ul><ul><ul><li>Wound infection </li></ul></ul></ul><ul><ul><ul><li>Septicemia </li></ul></ul></ul><ul><ul><ul><li>Outbreaks of UTI </li></ul></ul></ul>
  19. 25. PROTEUS-MORGANELLA-PROVIDENCIA <ul><li>PROTEAE </li></ul><ul><ul><li>Characteristics: </li></ul></ul><ul><ul><ul><li>Deaminate phenylalanine  produce phenylalanine deaminase </li></ul></ul></ul><ul><ul><ul><li>Motile </li></ul></ul></ul><ul><ul><ul><li>Grow on potassium cyanide medium (KCN) </li></ul></ul></ul><ul><ul><ul><li>Ferment xylose  non-lactose fermenter </li></ul></ul></ul><ul><ul><ul><li>Urease (+) </li></ul></ul></ul><ul><ul><ul><li>Primarily cause UTI, both nosocomial and community-acquired </li></ul></ul></ul>
  20. 26. PROTEUS <ul><li>Active motility via peritrichous flagella  (+) “swarming” on solid media  (+) expanding rings (waves) of organisms over the surface of the agar </li></ul><ul><li>Cell wall O antigens (OX-2, OX-19 & OX-K) of certain strains ( P. vulgaris ) cross react with several species of Rickettsiae  (+) Weil-Felix test </li></ul><ul><li>Present in human colon, soil and water </li></ul><ul><li>Virulence factors: </li></ul><ul><ul><li>Rapid motility at 37 0 C </li></ul></ul><ul><ul><li>Urease production </li></ul></ul>
  21. 28. Swarming gives rise to a very thin film of bacteria on the agar surface, but swarming periods are interspersed with periods when the cells stop and undergo a cycle of growth and division so that the colony has a distinct zonation, clearly seen in Fig. A. Ability to degrade urea to ammonia, by production of the enzyme urease (Figure B)
  22. 29. PROTEUS <ul><li>Proteus mirabilis </li></ul><ul><ul><li>Causes most community-acquired & nosocomial infections </li></ul></ul><ul><ul><li>2 nd leading cause of community-acquired UTI </li></ul></ul><ul><ul><li>Inhibited by penicillins </li></ul></ul><ul><ul><li>Indole (-) </li></ul></ul>
  23. 31. PROTEUS <ul><li>Proteus vulgaris </li></ul><ul><ul><li>Cause mainly nosocomial infection </li></ul></ul><ul><ul><li>Indole (+) </li></ul></ul><ul><ul><li>More resistant to antibiotics </li></ul></ul><ul><ul><li>Treatment of choice: cephalosporin </li></ul></ul>
  24. 33. Proteus <ul><li>Both Proteus vulgaris & Proteus mirabilis  (+) H 2 S production  blacken butt of TSI agar </li></ul><ul><li>Diseases other than UTI: pneumonia, wound infection and septicemia </li></ul>
  25. 34. Morganella morganii <ul><li>Formerly Proteus morganii </li></ul><ul><li>Urease (+) </li></ul><ul><li>Cause nosocomial UTI </li></ul>
  26. 36. Morganella morganii panophthalmitis. The conjunctiva was haemorrhagic and necrotic with mucopurulent greenish pus discharge. The cornea was oedematous and opacified.
  27. 37. Providencia rettgeri <ul><li>Formerly Proteus rettgeri </li></ul><ul><li>Member of normal intestinal flora </li></ul><ul><li>Causes UTI </li></ul><ul><li>Often resistant to antimicrobial therapy </li></ul>
  28. 38. CITROBACTER <ul><li>Formerly Bethesda-Ballerup group </li></ul><ul><li>Citrate (+) </li></ul><ul><li>Do not decarboxylate lysine </li></ul><ul><li>Slowly ferment lactose </li></ul><ul><li>Occur in environment and in human colon but majority of isolates from the urinary tract </li></ul><ul><li>Can cause UTI and sepsis in immunocompromised patients </li></ul><ul><li>Citrobacter diversus – most frequent isolate; also an important cause of neonatal meningitis and brain abscess </li></ul>
  29. 39. Diseases caused by members of the Enterobacteriaceae Major pathogen Representative diseases Minor related genera Escherichia UTI, traveler’s diarrhea, diarrhea, neonatal meningitis Shigella Dysentery Salmonella Typhoid fever, enterocolitis Arizona, Citrobacter, Edwardsiella Klebsiella Pneumonia, UTI Enterobacter Pneumonia, UTI Serratia Pneumonia, UTI Proteus UTI Providencia, Morganella Yersinia Plague, enterocolitis, mesenteric adenitis
  30. 40. Gram-negative rods causing UTI or sepsis Species Lactose fermented Features of the organism Escherichia coli + Greenish metallic sheen on EMB Enterobacter cloacae + Usually nosocomial infections & often drug resistant Klebsiella pneumoniae + Large mucoid capsule and viscous colonies Serratia marcescens - Red pigment produced; nosocomial infections; drug resistant Proteus mirabilis - Swarming phenomenon; produce urease Pseudomonas aeruginosa - Blue-green pigment; fruity odor; nosocomial; drug resistant
  31. 41. Lactose fermentation by members of the Enterobacteriaceae & related organisms Lactose fermented rapidly Lactose fermented slowly Lactose not fermented E. coli: motile; flat, nonviscous colonies Edwardsiella, serratia, citrobacter, arizona, providencia, erwinia, vibrios Shigella sp.: non-motile; no gas from dextrose Enterobacter aerogenes: raised colonies; often motile; more viscous growth Salmonella sp.: motile, acid & usually gas from dextrose Klebsiella pneumoniae: very viscous, mucoid growth; non-motile Proteus sp.: swarming on agar; urea rapidly hydrolyzed Pseudomonas sp.: soluble pigments; sweetish smell
  32. 42. Triple sugar iron (TSI) agar reactions Reactions Representative Genera Slant Butt Gas H 2 S Acid Acid + - Escherichia, Enterobacter, Klebsiella Alkaline Acid - - Shigella, Serratia Alkaline Acid + + Salmonella, Proteus Alkaline Alkaline - - Pseudomonas