Fastidious Gram Negative Rods PDF

156 Fastidious Gram Negative Rods GENERAL INFORMATION 1. Source - mouth flora Bordetella pertus...

156 Fastidious Gram Negative Rods GENERAL INFORMATION 1. Source - mouth flora Bordetella pertussis 2. Pathogenic in immunocompromised hosts; causes: Pertussis a a. P eridontal and jaw abscesses fancy name for (Eiken ella , Aggr ega tihacte1·, whooping Capnocytophaga) cough. b. Infectious endocarditis Take the c. Bacterernia ( Capnocytophaga, vaccine to be Cardiobacteri um) well off. Bordet-Gengou or 3. Grow slowly and require 5 - 10% CO2; NO growth on MAC Regan Lowe Are the best for me to grow. CAPNOCYTOPHAGA It may take many days to see 1. Capnophilic A mercury droplet colony. 2. F usiform shape HAEMOPHILUS INFLUENZAE 3. Bacter ernia/ septicemia 1. Sma ll, non-motile gram negative r od 4. Gliding motility BORDETEll.A PERTUSSIS 2. Requires growth factor s a. X factor = hemin 1. Gram nega tive coccobacilli; causes b. V factor = NAD "whooping cough" c. Both factors found in blood, but n eed h eat to break down red cells and 2. Requi r e special media release factors, so chocolate used a. Classic = Bordet-Gengou (potato infusion wi.th glycer ol and 20% d. Satellitism ❖ S. aureus produces V factor and SRBc's) and penicillin b. Regan/ Lowe (oxoid char coal agar , releases X factor by hemolyzing blood ❖ Haemophilus will grow in the 10% horse blood, cephalexin); hemolytic zone surrounding staph as lon ger shelf life satellite colonies on blood agar plate 3. Old m ethod for collection - cough plate; ❖ Need 5% h orse or rabbit blood to better to collect NP swab and plate see hem olysis directly; P CR to confirm ID e. Infections ❖ Meningitis - 4. Colony I& 2-4 year s a. Incubate 72-96 hrs, 35°C I& Preceded by n asopharyu geal b. Pinpoint, "mercury droplet" colonies colonization and hacter ernia HACEK GROUP OXIDASE CATALASE NITRATE INDOLE NOTES Aggregatibacter aphrophi/us - / weak+ - + - Colonies similar to (Haemophilus ) Aggregatbacte r ; Endo carditis A ggrega tibacter actino- +/- + + - Peridontal & Jaw A bsc esses; mycetemcomitans High Number in Plaque; Center (Actinobaci/lus) of Colony has 4 -6 Pointed St ar Cardiobacterium hominis + - - + Can Cause Endocarditis; Can Give False Positive Gram reac- tions Rosette g rouping Eikenella corrodens + - + - "Bleachy" Odor; Pits Agar; Three Zones of Growth; Peridontal and Jaw Abscesses Kingella kingae + - - - Septic A rthiritis ; Osteomyelitis in Children ; Spreading Corrod ing Colonies  157 ❖ Epiglottitis MYCOPLASMA AND UREAPLASMA I@' Ages up to 2 years; do NOT 1. Smallest free-living microorganisms collect throat culture (blood (125-250 nm) culture best) I@' May require intubation 2. Lack cell wall (bound by single triple ❖ Pneumonia 60 years layered membrane) ❖ Conjunctivitis (''pink eye") I@' Very contagious 3. Does not stain with Gram's stain; can ❖ Cbancroid - H. ducreyi use Dienes stain I@' Painful genital ulcers or soft 4. Center of colony grows into special chancres media ( contai.11s sterols) giving ll'.ii1f Gram stain of drainage appearance of inverted "'fried egg" shows tiny gram negative coccobacilli with a "school of 5. M. pneumoniae fish" arrangement a. Primary atypical pneumonia or "walking" pneumonia 3. Characteristics b. Causes positive cold agglutinin titer a. Growth only on chocolate, NOT blood agar plate ( unl.ess mixed with (> 1:32); false positive RPR c. Treat with erythromycin or S. aureus) tetracycline b. Use X and V discs on Mueller- Hinton agar to detect growth 6. Ureaplasma urealyticum requirements a. Non-gonococcal, non-chlamydia! c. Susceptibility zone interpretations urethritis, especially in males differ from conventional K- B zones b. Produces urease ( use Haemophilus test media c. Treat with tetracycline or (HTM), supplemented Mueller- spectinomycin Hinton agar and incubate in 5-10% CO2) 7. M. hominis d. Perform beta lactamase to a. May colonize GU tract; post partum determine sensitivity to ampicillin; fever cefuroxime, ceftriaxone, cefotaxime b. Tetracycline; resistant to (meningitis) erythromycin (all other Mycoplasma l£GIONELLA PNEUMOPHILA are sensitive) 1. Legionnaires' disease - severe SPIRILLACEAE pneumonia; Pontiac fever = milder 1. Rigid, helically curved rods with one or form more turns; corkscrew motility by polar flagella; gram negative 2. 75% illness due to L. pneumophila serogroups 1 and 6 2. Spirillum minor - "rat bite" fever a. Visualize by darkfield or stain with 3. Sources - potable water, faulty air Giemsa conditioner vents, lakes and ponds b. 2-3 spirals and bipolar polytrichous tufts of flagella 4. Identification c. No growth on artificial media a. Specimen - sputum, bronchial washing, pleural fluid, lung aspirate or biopsy b. Growth on BCYE (buffered charcoal yeast extract) with or without antibiotics but not on chocolate or blood X ud V Factors 111Jd c. Direct exam - Giemsa and Gram Susceptibility Testing for stain with basic fuchsin counter Haemophilus stain Isolation of Legioaella 158 O'fher Fastidious Gram Negative Rods ORGANISM DESCRIPTION DISEASE NOTES Bordetella pertussis Gram Neg Coccobacillus; Pinpoint, Pertussis ( Whooping Bordet-Gengou Media; NP Swab "Mercury Droplet" Colonies Cough) and Plate Directly Haemophilus Small, Non-Motile Gram Neg Rods H. influenzae - Causes Require X and V Factors H. ducreyi - "School of Fish" Influenza, Meningitis, and Epiglottitis H. ducreyi - Causes Genital Ulcers Legionella pneumophilia Growth on BCYE Legionnaires' Disease No Growth Routine Media Mycoplasma/Ureaplasma Colony Appears as Inverted Fried Egg M. pneumoniae - Dienes Stain NOT Gram Stain Causes Primary Atypical Pneumonia (-i-Cold Agglutinin Titer) Anaerobes 1. Clues to anaer obic infection 3. Culture techniques a. Foul odor to specimen a. '"Classic" principle of anaerobic b. Location in close proximity to a culture mucosal surface ! Jar technique (Gas Pak jar) c. Animal or human bite ! Catalyst - palladium p ellets d. Gas in specimen ♦:♦ Envelope generates H2 and CO2 e. Previous therapy with when water is added aminoglycosides ♦:♦ Methylene blue or resazurin - f. Black discoloration of blood indicators (blue and pink, containing exudates respectively when oxidized ; clear g. Presence of " sulfur granules" when reduced) h. Unique mor phology on gr am stain b. Other methods i. Failure to gr ow or ganism s seen on ♦:♦ Anaerobic bags - clear bag with smear aerobically gas gen erating ampules; plates can j. Growth in anaerobic zone or be read without opening bag bubbles in fluid media ❖ Roll tube technique ~ PRAS (pre-reduced 2. Specimen collection and transport anaerobically sterilized a. Site containing a r esident flora m edia) inoculated under (oral, GI, GU) not appropriate for constant flow of 0 2 - free gas anaerobic culture ❖ Anaerobic chamber b. Best to a spirate with syringe and ~ Plates put in chamber needle and place in a transport vial throu gh a pass box that is or tube under r educed conditions r educed (swab samples not as good) ~ Incubator in chamber ; also contains palladium catalyst