MUSCULOSKELETAL SYSTEM Flashcards

Question

what is NOCARDIA

Answer 1

-beaded, branching GPB classified in Actinomycetes group -found in standing water, decaying plants, & soil -infection via inhalation of organism or by direct inoculation of skin thru a cut/trauma -different from Actinomyces because it is a strict aerobe and partially acid fast. -Modified acid-fast stain - has lower concentration of acid alcohol decolorizer

Answer 2

mostly in immunocomp Candida spp (most common), Cryptococcus, Aspergillus. Dimorphs like Blastomyces dermatitidis, H. capsulatum

Answer 3

mostly in immunocomp Trichinella-eating larvae in undercooked wild game meat. Taenia solium- eating eggs on unwashed food or self- inoculation -causes Cysticercosis Toxoplasma gondii: contact with cat feces, eating undercooked meat with parasite in tissue cysts, or from mother to baby

Answer 4

-Muscle/tissue biopsy or needle biopsy of tissue (all sterile)– placed in sterile container -Abscess aspirate (Semi sterile) in sterile container -Abscess or muscle swab – (not sterile & least appropriate) contaminated by normal skin flora the transport media should maintain aerobic and anaero orgs -Blood cultures (sterile) not postive often since bacteremia is transient

Answer 5

-Grind or homogenize tissue specimen with, sterile tissue grinder -with small volume of sterile, filtered water. -Direct gram stain done on all specimens except blood culture (automated testing). -Specimens other than blood are cultured onto BA, CHOC, CNA, MAC, BRUC & THIO.

Answer 6

-Infection of fluid & tissues of joint mostly by bacteria -Orgs spread by hematogenous route (bloodstream). - direct injury puncture wounds. -from a nearby infection (contiguous).

Answer 7

-starts quick and tissue destructs in hours or days even in healthy people

Answer 8

-gradual & often affects people who have predisposing risk factors - less pain and swelling

Answer 9

-H. influenzae – < 2yrs old, less common now that babies are vaccinated against H. influenzae type B. -Kingella kingae (gram neg coccobacillus) - most common GN bacterial cause in this group

Answer 10

-Staphylococcus aureus most common 70 % - all ages -MRSA -N. gonorrhoeae – most frequent in young adults <30 yrs. -GAS & other BHS -S. pneumoniae -Enterobacterales & Pseudomonas aeruginosa -Anaerobes

Answer 11

-untreated GC spreads from genitals through body - disseminated gonococcal infection -can also spread to joints from blood stream symp-Fever, chills, skin rash, pain & swelling due to pus inside joint = purulent arthritis Add selective media for GC (NYC or TM) for Joint fluid specimens: if requested from dr or if you see gndc in direct specimen gram

Answer 12

-selectively enriched for NG -MHA with 5% sheeps blood -Vancomycin kills most GP. -Colistin kills all GN except Neisseria. -Nystatin kills fungi. -Trimethoprim Inhibits swarming by Proteus

Answer 13

-post surgery infection in people with artificial joints -wound wont heal and the bacteria spreads to bloodstream -happens in early recovery -1st 2 months -bacteria will adhere to artificial joint and form a biofilm which acts like a shield so the bacteria is hidden from immune system & AB -bacterial metabolism is slowed making it harder to culture, ID & treat tough in ppl with 2nd joint replacement, prior prosthetic infection, immunosupp, diabt, RA

Answer 14

Early onset (< than three months after surgery): Staph aureus Anaerobes Polymicrobial infection Delayed onset (3-12 months after surgery): Coagulase-negative staphylococci Propionibacterium sp Enterococci spp. Late onset (< than twelve months after surgery) Staph aureus Gram-negative bacilli BHS

Answer 15

-inflammatory arthritis due to autoimmune response triggered by infection in intestines, genitals or urinary tract. Orgs that infect Genitourinary tract that can cause RA -Chlamydia trachomatis, Neisseria gonorrhea, Mycoplasma hominis, and Ureaplasma urealyticum Orgs that infect Gastrointestinal tract that can cause RA Salmonella enteritidis, Shigella flexneri, and dysenteriae, Yersinia enterocolitica, Campylobacter jejuni, Clostridium difficile.

Answer 16

Specimens from genitourinary tract, respiratory tract, CSF, & blood should also be tested for bacteria to help determine original source of infection. Blood cultures are especially important since bacteria from joint infections often initially came from the bloodstream

Answer 17

-volume, color, turbidity, viscosity. -If clotted, break apart with sterile swab or loop -If too thick digest with hyaluronidase – releases trapped bacteria -If >1 mL received, centrifuge first use sediment for slides and culture media -if <1 mL received, do NOT centrifuge prep slides and culture directly

Answer 18

Hematology or Chemistry tests: -WBC with diff -MIC for crystals under polarized light , TP, GLU Micro lab tests -Direct Gram stain, culture for aerobes and anaerobes -BA, CHOC, *TM, CNA MAC, BRUC & THIO (THIO only indicated not actually done). -NYC or TM only if requested -Culture is the most definitive diagnosis of infective arthritis

Answer 19

Joint(synovial) fluid, Bone/bone marrow or Muscle Biopsy - are all sterile specimens. Direct specimen gram: Performed on all MS specimens except if piece of bone is received Presence/absence of pus cells with quantity Presence/absence of epithelial cells with quantity Presence/absence of organisms with quantity **For fluids: do not report epithelial cells** Gram result must be phoned to physician on Day 1

Answer 20

Perform oxidase on any colonies growing on either CHOC or TM to rule out GC. If oxidase neg, it is not GC, re-incubate both CHOC & TM for up to 72 hours If oxidase positive, perform Gram stain. (ALL NEISSERIA ARE OX POS) If GNDC then perform Identification tests. ID of this organism must be by 2 different principles before you can report it to doctor i.e., Biochemical, mass spectrophotometry, molecular, immunological. At the Michener we will be using MALDI (first - if neg just stop there and reincubate choc and TM- 72 hrs) & Bacticard (after pos maldi ONLY FROM selective media TM/NYC) -if colonies are too scant because you need 2 mcfar you should subculture to choc and then do test on D3 from the choc -if both pos then do a b lactamase test -the only susceptibility test -note youll reincubate CHOC/TM if GC by D3

Answer 21

Rapid carbohydrate fermentation: Glucose, maltose, sucrose and lactose – GC ferments only glucose. Other enzymatic tests for PIP OR PRO: We use Bacticard for this Biochemical ID: Vitek NH, rapid NH or API NH Nucleic acid amplification (NAAT): Amplify & detect nucleic acid sequences specific for GC. Don’t require viable organisms – test right from urine. -very sensitive only need one strand of target DNA or RNA gon needs to be sent to PHL all positive GC reports will remain preliminary until PH sends the AST results back.