Aerobic Gram Positive Cocci

1.

Open Ended

30 sec

1 pt

gram positive

Evaluate responses using AI:

OFF

Answer explanation

1. peptidoglycan content 2. lipid content (low)

2.

Open Ended

30 sec

1 pt

catalase

Evaluate responses using AI:

OFF

Answer explanation

H2O2 => H2O + O2 (gas bubble)

3.

Open Ended

30 sec

1 pt

catalase positive GPC

Evaluate responses using AI:

OFF

Answer explanation

1. Rothia (Stomatococcus) 2. Micrococcus 3. Staphylococcus

4.

Open Ended

30 sec

1 pt

Rothia

Evaluate responses using AI:

OFF

Answer explanation

1. R. mucilaginosa 2. low pathogenicity 3. encapsulated 4. mucosy 5. has rubbery consistency 6. whole colony can come off 7. many carry part of oral flora 8. non-pathogenic

5.

Open Ended

30 sec

1 pt

Micrococcus

Evaluate responses using AI:

OFF

Answer explanation

1. low pathogenicity 2. GPC, in pairs, tetrads, and clusters 3. found in environment 4. found in normal flora of skin 5. usually contaminant if found in culture 6. non-pathogenic 7. don't do species ID 8. seen in tetrads

6.

Open Ended

30 sec

1 pt

Micrococcus Identification

Evaluate responses using AI:

OFF

Answer explanation

1. catalase positive 2. often yellow pigmented 3. Furazolidone suceptibility (FX100) -micrococcus=resistant -staphylococcus=sensitive 4. modified oxidase (Microdase) -tetramethyl-p-phenylenediamine dihydrochloride in dimethyl sulfoxide (impregnated disc) -micrococcus=positive -staphylococcus=negative -rub microbe on disc and look for color change -quick and easy test 5. bacitracin susceptibility -micrococcus=sensitive -staphylococcus=resistant

7.

Open Ended

30 sec

1 pt

staphylococcus

Evaluate responses using AI:

OFF

Answer explanation

1. 28 species 2. found on skin and mucous membranes 3. facultative anaerobes 4. GPC, pairs, tetrads, clusters 5. everyone carries it, can be pathogenic

8.

Open Ended

30 sec

1 pt

S. aureus Disease States

Evaluate responses using AI:

OFF

Answer explanation

1. skin and soft tissue infections (SSTI's) 2. post-surgical wound infections 3. folliculitis, carbonkles 4. impetigo, scalded skin syndrome 5. food poisoning -most common cause of food poisoning -more short lived -free form toxin that is ingested -symptoms occur 2-6hrs after ingestion -24hr flu usually S. aureus 6. toxic shock syndrome -primarily affects women, produces toxic shock syndrome toxin -hypotension, fever, desquamation of palms and soles, chills, headache, vomiting, death -not common, but sever 7. other infections -pneumonia -bacteremia -endocarditis -osteomyalitis -metastatic abscess in deep organs

9.

Open Ended

30 sec

1 pt

S. aureus, Pathogenic Properties-Enzymes

Evaluate responses using AI:

OFF

Answer explanation

1. Hyaluronidase -hydrolyzes hyularonic acid (connective tissue) allows spread of infection 2. Beta-lactamases -hydrolyze penicillin antibiotics break down ring, resistant to penicillin antibiotics 3. leukocidin -kill WBC's, related to community acquired pneumoniae 4. alpha hemolysin -toxin lethal to red cells and WBC's neurotoxin, responsible for beta-hemolysis 5. beta-hemolysin (shpingomyelinase) -responsible for CAMP test 6. exfoliatins -responsible for scalded skin syndrome sloughing of skin layers 7. staphylokinase (Fibrinolysin) -enzyme that dissolves fibrin clots -important with coagulase testing => it breaks down clots

10.

Open Ended

30 sec

1 pt

S. aureus Pathogenic Properties-Toxins

Evaluate responses using AI:

OFF

Answer explanation

1. toxic shock syndrome toxins (TSST) -cause shock symptoms 2. Enterotoxins A-E -responsible for food poisoning symptoms

11.

Open Ended

30 sec

1 pt

S. aureus Lab Identification-colonial morphology

Evaluate responses using AI:

OFF

Answer explanation

1. creamy substance 2. whitish or yellow 3. beta hemolytic

12.

Open Ended

30 sec

1 pt

S. aureus Lab Identification

Evaluate responses using AI:

OFF

Answer explanation

1. catalase positive 2. coagulase positive -slide coagulase *takes couple of minutes *single most identifiable test *detects bound enzyme or clumping factor *fibrinogen=>fibrin *10% can be negative -tube coagulase *rabbit plasma in tube inoculate with colonies and incubate for 4 hours and look for clot *some S. aureus won't be + so leave at RT overnight (slows down reaction) *staph. aureus ruled out if tube is negative 3. latex agglutination

13.

Open Ended

30 sec

1 pt

S. aureus, special concerns

Evaluate responses using AI:

OFF

Answer explanation

1. small colony variants 2. smaller and clearer, don't look like staph 3. can be because of long antibiotic therapy 4. ex. cystic fibrosis

14.

Open Ended

30 sec

1 pt

S. aureus Treatment

Evaluate responses using AI:

OFF

Answer explanation

1. historically-Penicillin 2. today->90% are penicillin resistant 3. susceptibility testing is routine 4. drugs of choice: Penicillinase-Resistant Penicillins (PRPs) -oxacillin, Methicillin, Nafcillin

15.

Open Ended

30 sec

1 pt

S. aureus Methicillin Resistance

Evaluate responses using AI:

OFF

Answer explanation

1. Methicillin Resistant Staphylococcus aureus (MRSA) increasing in prevalence -first started with hospital acquired -now healthy people can get it 2. nosocomial infections 3. community acquired MRSA

16.

Open Ended

30 sec

1 pt

MRSA-controlling the Spread

Evaluate responses using AI:

OFF

Answer explanation

1. carrier states higher in health care setting 2. wash hands 3. contact isolation 4. screen patients upon hospital admission 5. treatment with mupirocin to eradicate carriage

17.

Open Ended

30 sec

1 pt

MRSA Detection

Evaluate responses using AI:

OFF

Answer explanation

1. heteroresistance -multiple populations within one culture, some show resistance others hide it 2. oxacillin Agar Dilution plate -grows 3. cefoxitin disk 4. selective chromogenic media -spectra MRSA -MRSA grows as blue only one that grows blue (has to be denim blue) -use this as surveilance of patients -expensive and fast media 5. molecular methods -detection of PBP2a *alteration of Penicillin Binding Protein *PBP-penicillin Binding Protein, where penicillin would bind and kill, so alter penicillin can't bind and has no effect -detection of mecA gene *encodes for alteration in PBP site, can detect with PCR

18.

Open Ended

30 sec

1 pt

MRSA treatment

Evaluate responses using AI:

OFF

Answer explanation

1. drug of choice-Vancomycin 2. new antibiotics -linezolid -daptomycin -ceftaroline 3. MRSA resistant to all beta-lactam drugs (penicillins, cephalosporins, carbapenems, beta-lactam/beta-lactamase inhibitor combinations)

19.

Open Ended

30 sec

1 pt

VISA, VRSA

Evaluate responses using AI:

OFF

Answer explanation

1. vancomycin resistance -need prudent use of vancomycin -not reliably detected by automated instruments

20.

Open Ended

30 sec

1 pt

S. aureus, Inducible Clindamycin Resistance

Evaluate responses using AI:

OFF

Answer explanation

D-zone test 1. clindamycin resistance is not shown unless induced, in the lab by an erythromycin disk -something in body causes clindamycin to be resistant

21.

Open Ended

30 sec

1 pt

S. aureus Penicillin confirmation

Evaluate responses using AI:

OFF

Answer explanation

1. need to confirm results before reporting penicillin as susceptible 2. disk diffusion zone edge test -Cliff vs. Beach 3. induced beta-lactamase

22.

Open Ended

30 sec

1 pt

coagulase negative staphylococci

Evaluate responses using AI:

OFF

Answer explanation

1. very common normal flora organisms 2. need to distinguish between contaminants and clinically significant isolates 3. three most significant species -S. epidermidis -S. saprophyticus-UTI -S. lugdunensis-has different susceptibility testing (higher virulence) 3. occur more in immunocompromised 4. skin contaminants 5. most just ID coagulase negative staph

23.

Open Ended

30 sec

1 pt

coagulase negative staph (CNS) disease states

Evaluate responses using AI:

OFF

Answer explanation

1. urinary tract infection (UTI) -especially S. saprophyticus 2. infections of indwelling devices -prosthetic heart valves, shunts, hips 3. bacteremia 4. oseomyelitis -after trauma or surgery

24.

Open Ended

30 sec

1 pt

CNS pathogenic properties

Evaluate responses using AI:

OFF

Answer explanation

1. slime production -like capsule production, protective covering -adhere to devices and produce slime layer -protect against phagocytosis and antibiotics 2. ability to acquire resistance to antimicrobials -give genetic info, obtain resistance from other organisms, some carry lots of resistance which help stay on skin

25.

Open Ended

30 sec

1 pt

CNS lab identification

Evaluate responses using AI:

OFF

Answer explanation

1. colonial morphology -creamy and white (more white-grey) -non-hemolytic 2. catalase pos 3. coagulase neg 4. commercial kits 5. MALDI-TOF 6. novobiocin -S. aprophyticus=resistant (<16mm) -other CNS=sensitive (>16mm)

26.

Open Ended

30 sec

1 pt

CNS treatment

Evaluate responses using AI:

OFF

Answer explanation

1. same as for STAU 2. MRS forms very common 3. Vancomycin resistance occasional 4. susceptibility testing is routine, except for S. saprophyticus -responds well to antibiotics for UTI

27.

Open Ended

30 sec

1 pt

catalase Negative GPC

Evaluate responses using AI:

OFF

Answer explanation

1. streptococcus 2. enterococcus 3. others -Abiotrophia, Aerococcus, Leuconostoc, Lactococcus, Pediococcus, Gemella, etc.

28.

Open Ended

30 sec

1 pt

Streptococcus

Evaluate responses using AI:

OFF

Answer explanation

1. various levels of pathogenicity 2. facultative anaerobes 3. catalase negative 4. GPC, in pairs and chains 5. colonize mucus membranes (GI tract) 6. aerobic or anaerobic environments 7. show chains and oval size

29.

Open Ended

30 sec

1 pt

hemolysis

Evaluate responses using AI:

OFF

Answer explanation

1. alpha: partial destruction of RBC, hemoglobin released in media (green color) 2. Beta: total destruction of RBC complete clearing around colonies 3. gamma: lack of hemolysis

30.

Open Ended

30 sec

1 pt

classification of streptococci

Evaluate responses using AI:

OFF

Answer explanation

1. baced on Ag in cell wall polysaccharides 2. antigenic composition (Lancefield Grouping) 3. the most clinically significant groups are A, B< C, F, and G 4. but it couldn't be that simple -S. anginosus (S. milleri) group 5. small colony strep dont follow landsfield -can type into all groups

31.

Open Ended

30 sec

1 pt

Streptococcus pathogenic properties

Evaluate responses using AI:

OFF

Answer explanation

1. M protein -cell surface antigens -antiphagocytic-disrupts engulfment by neutrophils -antibodies produced against M protein cross react with heart muscle 2. streptolysin O -antigenic-Ab response to that -oxygne labile-inactivated in presence of O2 -toxic to membranes cells WBC 3. streptolysin S -non-antigenic-no Ab produced -oxygen stable 4. erythrogenic/Pyrogenic toxins 5. streptokinase-spreader of infection, lyse blood and fibrin clots 6. DNAse-degrade host DNA 7. Hyaluronidase-allow for spread of infection to other tissues

32.

Open Ended

30 sec

1 pt

Group A strep-Strep. pyogenes

Evaluate responses using AI:

OFF

Answer explanation

1. pharyngitis (strep throat) -symptoms: sever sore throat, white exudate, fever, swelling lymph nodes -population: seen in 3-35 years olds -transmission: transmitted person to person talking spitting, school surfaces (thrives on surfaces for days)

33.

Open Ended

30 sec

1 pt

Group A Strep, disease states

Evaluate responses using AI:

OFF

Answer explanation

1. skin infections -impetigo-wound infections -cellulitis-soft tissue infections 2. other infections -tonsilitis -sinusitis -otitis media -Bacteremia

34.

Open Ended

30 sec

1 pt

Group A Strep, Complications

Evaluate responses using AI:

OFF

Answer explanation

1. Rheumatic Fever -follows pharyngitis -multisystem collagen-vascular disease (fever, rash, arthritis) -also known as scarlet fever 2. glomerulonephritis -follows pharyngitis or skin infection -deposits of antibody-strep antigen complexes in kidney damage glomeruli -glomerular lesions => hypertension => proteinuria -occurs couple weeks after 3. streptococcal Toxic Shock Like syndrome -invasive soft-tissue infections -"flesh eating bacteria" (Necrotizing Fascitis) *fatal within a day *fever, hypotension, renal impairment, respiratory failure, shock, death

35.

Open Ended

30 sec

1 pt

Group A Strep, Lab Identification

Evaluate responses using AI:

OFF

Answer explanation

1. culture -Beta hemolytic colonies -more gray and translucent 2. catalase neg 3. Bacitracin (Taxo A disk)=Sensitive 4. Serogrouping-latex agglutination -group specific carbohydrate antigen in cell wall -use acid to expose Ags on microbes so it can react with latex 5. selective media 6. PYR pos -pyrrolidonyl arylamidase -substrate is pyroglutamic acid-B-naphthylamide (impregnated disk) -reagent is N,N-dimethylaminocinnamaldehyde 7. serologic tests -ASO -ADNB -rapid strep antigen tests *Ab/Ag reaction, done directly on throat samples *if pos then really is group A strep, if neg then culture

36.

Open Ended

30 sec

1 pt

Group A Strep, Treatment

Evaluate responses using AI:

OFF

Answer explanation

1. necessary to prevent sequelae 2. drug of choice: penicillin 3. alternatives: cephalosporins, Erythromycin 4. Susceptibility testing not always necessary -never know who has allergy

37.

Open Ended

30 sec

1 pt

Group B Streptococcus-Strep. agalactiae

Evaluate responses using AI:

OFF

Answer explanation

1. neonatal infections -neonatal sepsis, pneumonia, meningitis -most common cause of neonatal meningitis -2-5% births affected by group B strep 2. transmission -from mom (usually during birth) super exposed to strep from moms normal flora -nosocomial in neonatal ward can be passed from baby to baby -25% women are carriers of group B strep 2. Non-neonatal infections -skin and soft tissue infections -UTI -bactermia -seen in diabetic patients

38.

Open Ended

30 sec

1 pt

Group B Strep Lab Identification

Evaluate responses using AI:

OFF

Answer explanation

1. usually beta-hemolytic colonies -weaker than Group A -more subtle hemolysis -may need to take colony off to see it 2. catalase neg 3. serogrouping-latex agglutination 4. CAMP pos -group B strep produces CAMP factor that reacts with S. aureus beta-hemolysin -this can ID microbe 5. hippurate pos -sodium hippurate => glycine + benzoic acid -ninhydrin reagent or ferric chloride reagent -reagent turns blue if glycine present 6. GBS screen -selective broth enhancement -LIM-broth with antibiotics to inhibit normal flora -Todd Hewitt wiht Gentamicin and Naladixic Acid -Prenatal vaginal/perianal screening -all women will get screened for Group B strep in 3rd trimester -give IV antibiotics while in labor so baby born with antibiotics to fight infection

39.

Open Ended

30 sec

1 pt

Group B Strep, treatment

Evaluate responses using AI:

OFF

Answer explanation

1. drug of choice: Penicillin 2. Susceptibility testing is not always necessary

40.

Open Ended

30 sec

1 pt

Streptococcus, Groups C and G

Evaluate responses using AI:

OFF

Answer explanation

1. Group C -S. equisimilis, S> zooepidemicus, S. equi, S. dysgalactiae (horse and human) 2. Group G -no designated species names 3. disease states: -pharyngitis-usually no sequeli -cellulitis -abscesses -bacteremia

41.

Open Ended

30 sec

1 pt

Group C and G lab Identification

Evaluate responses using AI:

OFF

Answer explanation

1. Beta-hemolytic colonies 2. catalase neg 3. serogrouping-latex agglutination 4. look like group A (cocci in chains)

42.

Open Ended

30 sec

1 pt

Group C and G, Treatment

Evaluate responses using AI:

OFF

Answer explanation

1. drug of choice: Penicillin 2. Susceptibility testing is not always necessary

43.

Open Ended

30 sec

1 pt

Streptococcus pneumoniae

Evaluate responses using AI:

OFF

Answer explanation

1. may be indigenous flora of respiratory tract 2. pathogenic properties -capsular polysaccharide -prevents phagocytosis -more capsulated more virulent

44.

Open Ended

30 sec

1 pt

S. pneumoniae, Disease States

Evaluate responses using AI:

OFF

Answer explanation

1. pneumonia-#1 cause of pneumonia 2. Bacteremia 3. Menigitis-common cause #1 in non-neonatal population 4. otitis media-ear infection #1 cause 5. sinusitis

45.

Open Ended

30 sec

1 pt

S. pneumoniae Lab Identification

Evaluate responses using AI:

OFF

Answer explanation

1. direct exam -lancet shaped GPC, pairs, encapsulated -can diagnose from direct exam -gram stain from sputum, spinal fluid -look like cat eyes -see clearing around (capsule) 2. culture -alpha hemolytic -mucoid 3. catalase neg 4. optochin (Taxo P disk)=sensitive -Ethylhydrocupreine hydrochloride ->14mm will be sensitive => + for S> pneumoniae 5. bile solubility pos -sodium deoxycholate reagent lyses colonies -done right on agar -colonies disappear -20min test 6. latex agglutination 7. serologic tests -look for Ags -done in urine test or spinal fluid

46.

Open Ended

30 sec

1 pt

S. pneumoniae Treatment

Evaluate responses using AI:

OFF

Answer explanation

1. drug of choice: Penicillin 2. Penicillin-resistance is increasing 3. Susceptibility testing is routine -methods: don't test penicillin directly, use oxacillin so predicts susceptibility 4. 25% are non-susceptible to penicillin 5. done on Mueller Hinton with blood agar goes in CO2 6. alternative treatment options: Cefotaxime, Ceftriaxone, Levofloxacin

47.

Open Ended

30 sec

1 pt

S. pneumoniae Prevention

Evaluate responses using AI:

OFF

Answer explanation

1. immunization -23-valent vaccine-elderly, people with underlying illnesses -7-valent vaccine-children <2 years *prevent childhood meningitis

48.

Open Ended

30 sec

1 pt

streptococcus viridans group

Evaluate responses using AI:

OFF

Answer explanation

1. S. anginosus (S. milleri) group -also small beta-hemolytic 2. S. bovis group 3. Many other species

49.

Open Ended

30 sec

1 pt

Strep viridans group clinical Significance

Evaluate responses using AI:

OFF

Answer explanation

1. most are normal flora of upper respiratory tract, (usually nonpathogens) 2. disease states -subacute endocarditis-#1 cause (damaged prosthetic valves) -dental carriers (S> mutans) -Abscesses and wounds (S. anginosus group) -Urinary tract infection (S. bovis grp.) -Bacteremia (S. bovis grp.) -almost only seen with patients with colon cancer

50.

Open Ended

30 sec

1 pt

Strep Viridans group Lab identification

Evaluate responses using AI:

OFF

Answer explanation

1. alpha or non-hemolytic -beta-hemolytic small-colony strains 2. catalse neg 3. PYR neg 4. Optochin=resistant 5. usually not necessary to ID to species level 6. exception #1 Strep anginosus group 7. exception #2-Strep bovis group -strep bovis group-bile exculin pos -esculin => esculetin + ferric citrate -streak slant and look for black 8. commercial kit systems -sugar fermentation -phoenix, vitek, API, IDS

51.

Open Ended

30 sec

1 pt

Strep anginosus

Evaluate responses using AI:

OFF

Answer explanation

1. buttery odor-alpha or non-hemolytic, or tiny beta 2. Voges-Proskauer pos 3. arginine pos

52.

Open Ended

30 sec

1 pt

Strep viridans group, Treatment

Evaluate responses using AI:

OFF

Answer explanation

1. drug of choice: Penicillin 2. Penicillin resistance is increasing (30%) 3. susceptibility testing is routinely performed on critical isolates

53.

Open Ended

30 sec

1 pt

Streptococcus Hemolysis Review

Evaluate responses using AI:

OFF

Answer explanation

1. strong beta-group A,C,G 2. weak/soft beta-Group B 3. tiny colonies with strong beta S. anginosus group (part of viridans group) 4. alpha-S. pneumoniae, viridans group 5. most common patterns. exceptions occur

54.

Open Ended

30 sec

1 pt

enterococcus

Evaluate responses using AI:

OFF

Answer explanation

1. cell wall contains lipoteichoic acid cell wall 2. has tougher cell wall (thick) 3. found in GI tract 4. 2 species most common -E. faecalis -E. faecium

55.

Open Ended

30 sec

1 pt

enterococcus disease states

Evaluate responses using AI:

OFF

Answer explanation

1. UTI 2. mixed wound infection 3. intraabdominal and pelvic infections 4. bacteremia and endocarditis 5. nosocomial infections

56.

Open Ended

30 sec

1 pt

Enerococcus Lab Identification

Evaluate responses using AI:

OFF

Answer explanation

1. non-hemolytic, or alpha (or beta) -can be variable -translucent grey 2. catalase neg, but pseudocatalase pos 3. PYR pos 4. Bile exculin pos 5. 6.5% NaCl pos (salt tolerance) -broth starts as purple if grows shows turbidity -can also turn purple to yellow

57.

Open Ended

30 sec

1 pt

Enterococcus treatment

Evaluate responses using AI:

OFF

Answer explanation

1. drug of choice: high does penicillin +/- an aminoglycoside (ex. gentamycin) 2. susceptibility testing is routine 3. vancomycin resistance (VRE) (6-8%) 4. high level aminoglycoside resistance (HLAR) 5. gives plasmids to S. aureus

58.

Open Ended

30 sec

1 pt

VRE Detection

Evaluate responses using AI:

OFF

Answer explanation

1. selective Chromogenic Media -Chrom ID VRE (BioMerieux) 2. look at rectal sample 3. can differentiate for resistance 4. E. faecalis => blue green 5. E. faecium => violet

59.

Open Ended

30 sec

1 pt

Miscellaneous GPC species

Evaluate responses using AI:

OFF

Answer explanation

1. Abiotrophia/Granulicatella -nutritionally variant streptococcus 2. Aerococcus 3. Leuconostoc 4. Lactococcus 5. Pediococcus 6. Gemella

60.

Open Ended

30 sec

1 pt

Miscellaneous GPC

Evaluate responses using AI:

OFF

Answer explanation

1. normal flora of mucous membranes 2. opportunistic pathogens 3. resemble staph and strep 4. differntiated by gram stain morphology, vancomycin suceptibility, PYR, LAP, pyridoxal disk, satelliting around STAU 5. often catalase-negative GPC in clusters 6. low pathogenicity, part of normla flora 7. can cause bactermia, wounds, UTI (usually in compromised)

61.

Open Ended

30 sec

1 pt

Abiotrophia/Granulicatella

Evaluate responses using AI:

OFF

Answer explanation

1. nutritionally variant streptococcus 2. satelliting around S. aureus 3. these will grow on chocolate agar and not on blood

62.

Open Ended

30 sec

1 pt

Aerococcus

Evaluate responses using AI:

OFF

Answer explanation

1. urinary tract pathogen 2. catalase neg 3. GPC in clusters 4. tiny, alpha-hemolytic

63.

Open Ended

30 sec

1 pt

Leuconostoc and Pediococcus

Evaluate responses using AI:

OFF

Answer explanation

1. catalase neg 2. GPC in clusters 3. intrinsic vancomycin-resistance

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