Rickeffsiae and Acid Fast Bacilli PDF

161 Rickeffsiae 5. Arthropod bite - causes fever, h eadach e,...

161 Rickeffsiae 5. Arthropod bite - causes fever, h eadach e, r ash (Q fever - no rash and 1. Small gram negative coccobacilh organism s urvives outside host) 2. Obligate intracellular parasites 6. Weil-Felix test 3. Spr ead by arthropod (insect) vectors a. Proteu s OX-19, OX-2 and OX-K u sed as antigen s to detect 4. Seen better with Giemsa Rickettsial antibody b. 4-fold rise in titer or l: 160 titer Most Common Rickeffsiae ORGANISM VECTOR PROTEUS NOTES OX19 OX 2 OX K R. akari House - - - (Rickettsial Pox) Mites Coxiella burnetti Inhaled - - - Confirm with CF Test (Q Fever) R. prowazekii Louse + Variable - (Typhus Fever) R. rickettsiae Tick + + - Characteristic Rash on Palms of Hand (Rocky Mt. Spotted Fever) and Soles of Feet R. typhi Rat Flea + + - (Murine Typhus) Acid Fast Bacilli 6. Gr owth requirements a. Lowenstein-Jensen; 60% egg in nutrient base; malachite green; asic solidified into slants after inspissation lde1Jtjfy (h eat to 85°C until protein coagulates) b. Tween 80 (oleic acid) - aids in Mycobacteria dispersing colonies in liquid media 1. Morphology - slim gram variable rods; c. ,t.C02 (especially in first 24 hrs) don' t gram stain well due to high lipid d. Most grow at 36°C; some require content in wall 3o c e. Takes 3-6 weeks for growth 2. Acid fast stain f. Automated liquid culture systems a. Ziehl-Neilsen - " hot" stain for rapid growth & susceptibility b. Kinyoun - "cold" stain testing 3. Auramine-Rhodamine - fluorescent 7. Identification by nucleic acid probe stain SPECIMEN COLLECTION 4. All stains based on presence of mycolic 1. Sputum (first morning; on 3 acid (lipid-wax) in cell wall consecutive mornings), bronchial & gastric washings, urines and tissue 5. Any number seen on a smear is significant 2. Collect a septically and place in sterile , tightly capped container 3. May be refrigerated overnight (neutralize gastrics and urines ifholding overnight) 162 Branching Gram Positive Rods ORGANISM ATMOSPHERE CASEIN TYROSINE XANTHINE ACID FAST Actinomyces Israeli Anaerobic N.A. N.A. N.A. N.A. Nocardia asteroides Aerobic - - - Partially Nocardia brasiliensis Aerobic + + - Partially Eval11ate Sm~ 1ro.m )'Ui80C.U1.te Mycoba(:tefia with MycobacteriJJ J>.isment Groupintf Collection and Handliag of I.D. and Rapid Reporting of Mycobacterial Specimens M. tubercrJoais SPECIMEN DECONTAMINATION l. N-acetyl-L-cysteine (N.4LC) - mucolytic; NaOH decontaminates; time dependent REMEMBER! Mycobacterium tuberculosis 2. Stain and report slides within 24 hrs of processing Infects 1/3 of world's poprJation 3. Centrifuge decontaminated specimen Is spread by respiratory droplets for 20 min at 3000 rpm prior to making Is resistant to drying smears and inoculating media ( use Is resistant to many disinfectants sediment) Is best known for respiratory disease HaH"cauliflower" colonies on LJ Requires long-term treatment Has MDR variallts Can be p-own in automated systems Can be identifi.ed by nucleic acid probes Use skm test for screening in U.S. Mycobacterium avium complex Are enviroD.D.'lental organisms May cause pulmonary disease May cause disseminated disease May infect immunocomprised patients Non-pigmented colonies on LJ Can be identifi.ed by nucleic acid probes Mycobacterium leprae Causes leprosy (Hansen disease) Infects skin, mucous membranes, nerves (See Mycobacteria chart on following Causes a progressive disease that is treatable page.) Grows best in armadillo footpads  Differentiating Mycobacterla Growth < 7 days on traditional Niacin Nitrate Tween 80 Tellurite Growth on Notes media Reduction (3 days) MacConkey Hydrolysis M. tuberculosis - +... +. , ·~~: > 5 days - - Rough & buff, serpentine.·.. :3"=":' cording on culture ' M. bovis - - - > 5 days - - Rough & buff colony, serpentine cording; susceptible to TCH., ,;; - - ;_:; M. kansasii :j. ff" < 5\ Jay~. - - Photochromogen.. f!, ~ I! ~; :~!-- :-t;r; ~r:· " ·ff! M. marinum - V - ,;\ s11a)lr - - Photochromogen · · ¥ : n: (30° C optimum temperature) M. scrofulaceum - - - - - - Scotochromogen M. gordonae - - - 5·10 days - - Scotochromogen - ,-. iif~ ;:i.i:· M. avium - - - + - Non-photochromogen :,: - - Non-photochromogen M. ulcerans - - - - (32" C optimum temperature) II' ·:,;· + - M. fortuitum " !!, '"!I! + =~:~~ - V + Rapid grower ~:·....:. ~?;. f( + M. chelonei " V.. ,l) r:· ~ - V + Rapid grower v = variable Shaded areas = Key reactions differentiating similar genera Photochromogen - produces pigment in light Scotochromogen - produces pigment in dark and light Non-photochromogen - produces no pigment Rapid grower - growth in < 7 days -°' vJ 164 Specimen Source and Potential Pathogens BODY "NORMAL" EXPECTED SITES/SOURCE FLORA PATHOGEN NOTES Throat, oropharynx Alpha Strep Strep Group A Staph sp. Neisseria sp. Corynebacterium diphtheriae Pseudomembranes when toxin produced Gram+ Rods Anaerobes Bordetella pertussis Whooping cough; confirm with fluorescent antibody test Haemophilus influenzae Acute epiglotitis in children (Do not attempt throat culture; blood culture best.) Eye Same as above Chlamydia Newborns except in lesser numbers Neisseria gonorrhoeae Newborns Ear " Pseudomonas aeruginosa Swimmer's ear H. influenzae Otitis media Streptococcus pneumoniae Otitis media Lower Respiratory Tract H. influenzae Early morning sputum specimen best; should (sputum) have less than 1O - 15 squamous epithelial cells per LPF (represents oral flora contamination) S. aureus " Streptococcus pneumoniae " Klebsiella pneumoniae " Mycoplasma pneumoniae " Mycobacterium tuberculosis " Legionella " Fungi " Transtrachial Aspirate, Should be Anaerobes Lung Tissue sterile Bronchial Washing Resident oral No anaerobic set-up; AFB and mycology set-up flora Gastric Specimens Helicobacter pylori Rapid urease test Colon Profuse flora Shige/la Selective and differential media on stools (MAC, EMB, HE, XLD, selenite, or GN broth); subcul- lu re to selective media after 6 - 12 hours Salmonella " Campylobacter jejuni Microaerophilic at 42' C Yersinia entercolitica MAC after 48 hours at room temperature Vibrio cholerae TCBS Toxigenic E coli Other tests better than culture Clostridium difficile EIA best  165 BODY "NORMAL" EXPECTED SITES/SOURCE FLORA PATHOGEN NOTES Urinary Tract Normally sterile E.coli Midstream catch with proper skin preparation; (May be conta- >100,000 organisms per ml for infection minated with (work up smaller number if pure culture and fecal flora) white cells present) Other gram neg rods " E. faecalis " Staphylococcus sp. " Genital Tract Neisseria gonorrhoeae Male - purulent discharge, do gram stain; Female - gram stain not sensitive or specific enough, do culture for GC (Thayer-Martin: selective media for GC) Chlamydia trachomatis Serological tests more accurate and faster Strep Group B Significant in pregnant women Herpes simplex Trichomonas vagina/is Parasite, wet mount Treponema pallidum Darkfield Gardnerella vagina/is Implicated in vaginosis; look for "clue cells" CSF Normally sterile H. influenzae Children under 5 Neisseria meningitidis E.coli Neonates Strep Group B Neonates Cryptococcus lmmunocompromised patients Listeria lmmunocompromised patients Deep Wounds/Abcesses Anaerobes and Aerobes; Bypass normal flora in collection; needle depends on site aspirate better than swab Superficial Wounds S. aureus (pustules, dermatitis, rashes) Strep Group A Pseudomonas aeruginosa Blood Normally sterile In immunocompromised and prosthetic heart device patients, any organism is considered pathogenic Colony Count Indicating UTI Organism Associated with Specimen Collection and Peptic Ulcers Baadlmg of NP Swab