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Flashcards in Mirobiology Deck (84):
1

Hansen's Disease

Caused by Mycobacterium leprae and has two forms

Tuberculoid - Formation of skin plaques
Treated w/ Dapsone/Rifampin

Lepromatous- Highly contagious and primarily affects the limbs
Treated w/ Dapsone/Rifampin/Clofazime

2

Mycobacterium tuberculosis (Shootout at TB Corral)

GPR, non-spore forming, acid fast, obligate aerobe

Can be visualized w/ Auramine stain

Nitrate (+)

*Acquired thru inhalation of respiratory droplets; will proliferate in alveolar macrophages

*Treated w/

R(ifampin)
I(sonazaid)
S(treptomycin)
E(thambutol)

3

Stages of M. tuberculosis infxn

Primary- affects the lungs and forms calcifications that can be seen on an x-ray

Miliary- Causes multi-organ failure; usually happens in CF pts.

Latent- Occurs in immunocompromised pts due to decreased TNF-a release
*Hemoptysis and Night sweats=classic sign
Cachexia will occur

Treatment: Rifampin/Isonaizid/Ethambutol

4

Streptococcus pneumoniae (Knight "Numero Uno")

GP diplococci, encapsulated, a-hemolytic

Bile solubility (+)

Catalase (-)

*Optochin (S)

Quellung Rxn: (+)

VFs: Pneumolysin- destroys ciliated epithelial cells
Adhesins
IgA proteases

*#1 cause of: Meningitis
Otitis Media
Pneumonia (community-acquired)
Sinusitis

Treatment- Penicillin G
-Vaccine available for immunocompromised

5

Streptococcus agalactiae

GPC, B-hemolytic, sialic acid on capsule

Bacitracin (R)

CAMP test (+)-will see satellite growth of S. aureus

Common cause of neonatal meningitis (NF of vaginal tract)
Early onset=>>High mortality rate, common in premature infants
Late onset=>> You'll be alright, probably

Treatment: (Penicillin/Erythromycin,)

6

Streptococcus pyogenes (Pie Baker)

GPC, B-hemolytic, encapsulated

Contains M-protein that prevents phagocytosis and F-protein which mediates adherence to mucoepithelium by binding fibronectin

Streptolysin O => (+) ASO test

Bacitracin (S)

Common cause of: Scarlet-Fever, Erysipela, Pharyngitis, Necrotizing fascitis

Sequelae of pharyngitis: RHD (cross-reactivity w/ myosin in heart)
AGN

Treatment: Penicillin

7

Staphylococcus Aureus (Moses)

GPC, Coag (+) (activates fibrinogen), yellow-appearance on blood agar

Enterotoxins =>>food-poisoning w/ rapid developing vomiting

TSST-1 =>> Toxic-Shock Syndrome; assoc. w/ tampon use

Panton-Valentine Leukocidin: Causes lysis of macrophages and PMNs

Protein A-Component of cell wall that binds Ig

Mannitol Salt agar- grows yellow

*Common cause of acute bacterial endocarditis in IV drug users
And
Septic arthritis

*Can also cause scalded-skin syndrome w/ (+) Nikolsky's sign

Treatment: Topical-cephalosporin or penicillinase-resistant penicillin; Blood- Vancomycin

8

Klebsiella pneumoniae

GNR, non-motile, common UTI cause

*Also a common cause of nosocomial pneumonia

9

Shigella (She-gorilla)

GNR, facultative anaerobe, acid-stabile

*most infectious intestinal pathogen

Lactose (-)

H2S (-)

Performs Type III secretion => release of inflammatory cytokines

*Shiga toxin causes HUS and `cleaves the 28sRNA of ribosome

Test: methylene blue stain of feces; look for PMNs

Treatment: Fluid and electrolyte replacement
-If sever enough, Ciprofloxacin

10

Reiter's Disease

Caused by Shigella sp.

Will see arthritis, conjunctivitis, and urethritis

*Most pts are male and HLA-B27 positive

11

Salmonella sp. (Salmon dinner)

GNR, motile, encapsulated, and acid-labile

H2S (+)

Hektoen Agar => Grows black

Performs Type III secretion

12

Typhoid Fever

Caused by Salmonella typhi

Will see rose-colored spots appear on pt.

Invades lymphatics and is carried into the blood =>> Facultative intracellular organism

Treatment: FQN
-Live attenuated vaccine available

13

Escherichia coli (E. cola's Soda Fountain)

GNR, B-hemolytic

Lactose (+)

Indole spot test (+)

Nitrate (+)

Catalase (+)

*Contains p-fimbriae which binds to P-antigen on RBCs (Pyelonephritis pili)

14

EHEC

O157:H7

Cause of Hemolytic uremic syndrome
-Production of Shiga-like toxin that inhibits 60s ribosome
=>>Bloody diarrhea, cramps

15

ETEC

Cause of WATERY diarrhea and is transmitted via infected h2o sources

Has a heat labile (inhibits cAMP) and heat stabile (inhibits cGMP) toxin

16

Bordetella pertussis (Board and Care)

GN cocco-bacillus

*Binds to mucocilliary escalator via hemaglutinnin

Oxidase (+)

DFA test => Sensitive but not selective

*Toxins: Pertussis- inhibits Gi via ribosylation
Invasive AC- increases cAMP opening ion channels and expelling intracellular materials

Treatment: Erythromycin

17

Pseudomonas aeruginosa (Pseudo Mona)

GNR, obligate aerobe, encapsulated

Green pigment=pyoverdin; Blue pigment=pyocyanin

Oxidase (+)

VFs: Exotoxin A => inhibits protein synthesis
Exoenzyme S- required for dissemination in burn patients
Alginate- Promotes adherence to respiratory epithelium
Elastase- Breaks down ECM proteins; under influence of quorum sensing process

Common causes folliculitis from contact w/ unclean water (hot tubs)

Common cause of Swimmer's Ear, septicemia in burn pts, and ecthyma gangrenosum

Treatment: Piperacillin, Fluoroquinolones, AGCs

18

Mycobacterium Leprae (Good, Bad, and Lion-Faced)

GPR, non-spore forming, acid fast

-diagnosed by AFB stain

-person-to-person transmission

Reservoir = Armadillo

19

Staph MRSA

mecA gene responsible for resistance is located on the

20

Staphylococcus epidermidis

CNS

Transmitted thru infected catheter; commonly infects previously damaged or artificial heart valves

21

Staphylococcus saprophyticus

CNS

Novobiocin (R)

22

Anti-DNase B

Important marker in S. pyogenes infxns; depolymerizes cell free DNA in pus

23

Strep. viridans (Knight "Numero Uno")

GPC, a-hemolytic

Optochin: (R)

#1 cause of acute bacterial endocarditis

Central role in dental caries

24

Enterococcus (VRE)

GPC, can hydrolyze esculin

Bacitracin: (R)

Bile solubility: (-)

VFs: Aggregation substance
Carbohydrate adhesins
Cytolysins
Antibiotic resistance (AGCs, Beta-lactams, and Vancomycin)

25

Proteus mirabilis

Can cause UTI and large amounts of urease in the bacteria will cause the ppt. of calcium

=>>Kidney stones

26

Pseudomonas infxn in CF lung

Type III hypersensitivity

=>>Immune complexes stimulate macrophages excessively and cause tissue damage

27

Caveats of PPD test

-Cross reactivity w/ other Mycobacterium species

-IC pts. may not react

-(+) test if received BCG vaccine

28

Most common Mycobacterium infxn in AIDS pts

Mycobacterium avium-intracellulare

-Readily diagnosed in blood

29

Mycobacterium kansasii

Forms yellow colonies; somewhat common in AIDS pts.

Found in the South

30

Neisseria meningitidis

GN-diplococci; non-motile, aerobic; grows best on chocolate agar

VFs: Porins A and B (B facilitates epithelial invasion and inhibits leukocyte fnxn)
LOS
Transferrin-Binding Protein

*Complement deficiences => Increased risk of infxn

Labs: Culture= Gold Standard
Growth on MTM agar
CTA: Can utilize glucose and maltose

Treatment: Ceftriaxone; prophylaxis of contacts also necessary

31

Meningococcemia

Severe circulatory collapse w/ DIC, purpuric rash, ischemia of the extremities, and fever

=>Can also lead to Waterhouse-Friderichsen syndrome

32

Chlamydia Trachomatis

Organism w/ cel membrane lacking muramic acid; visualized w/ Giemsa Stain

Serotypes A-C => Trachoma (most common cause of blindness worldwide)

Serotypes D-K => STD; can be asymptomatic in women but lead to PID and neonatal conjunctivitis if transmitted to a baby during childbirth

Serotypes L1-L3 => LGV; starts off as painless ulcer, progresses to tender lymphadenopathy

Treatment: Doxycycline

-Erythromycin in neonatal pneumonia/conjunctivitis

33

Mycoplasma pneumoniae

*Has no cell wall but membrane contains sterols (like a persons)

VF: P1 binds glycoprotein on cilia
=>>Destruction of ciliated epithelial cells

*ACTS AS A SUPER-ANTIGEN; stimulates excess TNF-a, IL-1, and IL-6 release

Increased incidence in young people in close contact
-Military recruits

-Can also cause erythema multiforme and Steven-Johnson syndrome

*X-rays show severe, patchy infiltrate, however, patient only has walking pneumonia

Treatments: Macrolides

34

Neisseria Gonorrhoeae (not on exam 2)

GN-diplococci; non-encapsulated

Causes PID, DGI, and asymmetric arthritis

*Opthalmia neonatorium in newborns

-Pili are used to deter neutrophilic digestion and undergoes antigenic vriation

Treatment: Ceftriaxone and Azithromycin (for concurrent Chalmydia infxn)

35

Haemophilus influenzae

tiny GNR that requires X and V factors

Non-typeable strains => Unencapsulated; produced minor infxns like sinusitis

Typeable strains => Encapsulated; produce major invasive infxns (Hib)

VFs: OMPs P2 and P5- bind bacteria to mucous
LPS
Pili
*Invades by separating tight jnxns of columnar epithelium

Labs: Staph-Spot Test => Satellite growth
Grows best on chocolate agar

Treatment: PRP vaccine
Ceftriaxone if serious

36

Hib Meningitis

Most common cause of infant meningitis prior to immunization

Long term sequelae include developmental abnormalities, visual defects, and hearing loss

*Increased risk of infxn if...=> complement deficient
Post-splenectomy
No anti-PRP abs

37

Hib Epiglottitis

Abrupt onset of fever, sore throat, and dysphagia

*Pts. often DROOL too

-May require emergency nasotracheal intubation

38

Hib Arthritis

Often affects a single large joint; treatment requires surgical drainage

39

Histamines

Source: Mast cells, basophils, platelets

Action: Increased vascular permeability, vasodilation, platelet activation

40

Prostaglandins

Source: Mast cells, PMNs

Action: Vasodilation, Pain (PGE2), Fever (PGE2)

41

Leukotrienes

Source: Mast cells, PMNs

Action: Increased permeability, Chemotaxis (LTB4), PMN Activation

42

TNFa, IL-1, IL-6

Source: Macrophages, Mast cells, Endothelial cells

Action: Fever, Hypotension, Endothelial activation

43

Platelet Activation Factor

Source: PMNs, Mast cells

Action: Increased vascular permeability, platelet activation, degranulation of platelets, vasodilation

44

Kinins

Source: Liver

Actions: Pain, vasodilation, smooth muscle contraction, increased vascular permeability

45

Facets of a Granuloma

Inner focus of granulomatous inflammation

Central collection of epithelioid cells* (characteristic)

Surrounding lymphs and possible caseating necrosis

*Epithelioid cells can combine to form giant cells

46

CGD of Infancy

Deficiency off NADPH oxidase => chronic infxns

47

Echinocandins

Inhibitors of glucan synthesis

48

Nikkomycin

Inhibitor of chitin synthesis

49

Sodarins

Inhibitors of fungal protein synthesis

50

Candida albicans

Yeast @ 25 degrees; Mold at 37 degrees

VFs: Adherence to tissues
Germ tube production (proteinase)
Gliotoxin (immunosuppresant)
Dimorphic properties

Diagnosis: Calcoflour white prep. w/ KOH; should see pseudohyphae
*Germ-tube test faster

Treatment: Fluconazole OR mouthwash if only oral candidiasis

51

Oesophageal candidiasis

Severe cottage-cheese appearance of fungi on tongue and down esophagus; occurs in IC

EXCEPTION- Women can get vaginal candidiasis on antibiotic therapy

52

Chronic Mucocutaneous Candidiasis

Chronic, non-invasive infxns of mucous membranes, hair, and nails due to insufficient T-cell levels

-Requires multiple anti-fungal treatments

53

Aspergillosis

Causes a variety of nosocomial acquired, invasive infxns

-Most common are of the bronchi or pulmonary parenchyma

Diagnosis: Rapid growth on potato agar
Histological ID of septate, dichotomously branching hyphae
Immunological ID

Treatment: Amphotericin-B or 5-flucystoine for invasive forms

54

Mucormycosis (Rhizopus)

Aseptate, non-staining, ribbon-like hyphae that bend at right angles

*Outbreaks assoc. w/ use of infected bandages or taping

Clinically similar to Aspergillus

*Seen w/ hospital construction exposure, organ transports, immunosuppression theraopy

Treatment: Amphotericin-B

55

Rhinocerebral mucormycosis

Invasive disease common in severely burnt patients that is accompanied by facial pain, headache, dilated pupil, and a change in mental status

*Due to fungi infecting the nasal cavity and spreading to the nearby soft tissue

*Terminal event in patients with acidosis or diabetes

56

Cryptococcus neoformans

Major opportunistic organism in AIDS pts. and most common cause of fungal meningitis

*Pulmonary infections will appear nodular

Diagnosis: India Ink (+)
Niger-seed agar (+)
Urease (+)
Phenol oxidase (+) - blocks Epinephrine
Budding, encapsulated yeast cells
*Latex agglutination test (most common)

Treatment: (Induction Therapy) Amphotericin-B + Flucystosine -2 weeks
(Consolodation Therapy) Oral fluconazole or itraconazole - 8 weeks
*If AIDS pt, should take follow-up CSF samples at the end of therapies and for a year; CULTURE THESE

57

Pneumocystis Carinii

Resembles protozoa and fungi; often the first infxn to present in AIDS pts

Diagnosis: Methenamine Silver-stain => Cup-shaped organism
*Often presents as walking pneumonia

Treatment: Trimethoprim-Sulfamethoxazole

58

Viral ether sensitivity

Enveloped viruses EXCEPT Poxvirus

59

Non-infectious viruses

Either have empty capsids or under-go faulty maturation

60

Pox Virus Envelope

Is not received by budding; is more complex and synthesizes its envelope in the cytoplasm

61

Defective Interfering Proteins

Produced after high MOI cells and cannot replicate on their own due to lack of all of their NAs

=>> Require "helper virus" to complete its defective genome

*Interacts more strongly with polymerase than the full-length helper virus and leads to persistent infections

62

Viral destruction of cell polysomes

Poliovirus

63

Negri bodies

Inclusion bodies formed from rabies virus

64

Guarnieri bodies

Inclusion bodies formed from smallpox virus

65

Only single-stranded DNA virus

Parvovirus

66

Only Double-stranded RNA virus

Reoviridae

67

Active Trachoma

Presence of yellow follicles on the upper conjunctiva along w/ the presence of Herbert's pits in the cornea

68

Cicatricial Disease

Evidence of pannus, trichiasis, and corneal opacity

=>>blindness

69

Chlamydia cervicitis

Visible mucopurulent discharge along w/ erythematous and febrile cervix

*Can present alongside Fitzburgh-Hugh Syndrome

70

Fitzburgh-Hugh Syndrome

Perihepatitis w/ inflammation of the liver capsule that is seen w/ C. trachomatis infxns

71

Parinaud oculoglandular Syndrome

Conjunctivitis alongside periaucular, submandibular, and cervical lymphadenopathy

-Caused by LGV serotypes of Chlamydia

72

Herpes family

a= HSV, VSV

b=CMV

y=EBV

73

Herpesvirus structure

Double-stranded, enveloped, iscosahedral

74

Four configurations of Herpes DNA

Prototype, Inverted Short (IS), Inverted Long (IL), Inverted short and long (ISL)

*Only one type of DNA per viral particle

75

Extracellular receptor for HSV

Heparan sulfate

76

Immediate herpesvirus protein synthesis

a =>>regulatory proteins

77

Early herpesvirus proteins

b =>>enzymatic and needed for DNA replication

78

Late herpesvirus proteins

y =>> structural and used to synthesize the progeny virus

79

EIEC

Invades at the M-cells and produces dysentery-like diarrhea

80

Hemadsorption

RBCs attach to the surface of infected cells via the viral antigens of hemagluttinin that are being presented

81

TCID50

The dilution of virus at which 50% of tissue cultures are showing CPE

82

Herpes virus DNA replication

After moving into the nucleus, the DNA circularizes at internal redundancies and undergoes rolling replication

83

Where does formation of the herpes virus capsule occur?

The nucleus

84

Common CPE of herpesvirus

Multi-nuclear end giant cells