Bacteria Flashcards

Question

Strep viridans important facts

Answer 1

- commensal species found in oral cavity (also GI/GU tracts) - dental caries - dental manipulations can send bacteria into bloodstream ==> repeated buildup ==> **sub-acute endocarditis** optochin resistant: "viridans strep live in the mouth because they are not afraid of-the-chin"

Answer 2

*E. faecalis* and *E. faecium* gram positive cocci catalase - gamma hemolytic grow in 6.5% NaCl and bile - resist the 6.5% N.CA sign - jester's boots resistant to most antibiotics, including vancomycin (source of vancomycin resistance in *S. aureus*) - protestors resisting arrest, resisting getting put into van

Answer 3

one of the most common nosocomial (hospital origin) infections - UTIs - wound infections - endocarditis - bacteremia and sepsis following IV catheters

Answer 4

non-Enterococcal Group D Strep, AKA Strep gallolyticus - gamma hemolysis (no hemolysis) - grows in bile, but NOT 6.5% NaCl - colonizes gut - colon cancer patients: bacteremia, sub-acute endocarditis "Bovis in the blood = cancer in the colon"

Answer 5

- gram positive rod, spore-forming; "boxcar" like chains - only bacteria with **polypeptide** capsule (buff Vikings), made of D-glutamate - toxin has 3 protein subunits: Protective Antigen (PA), Edema Factor (EF), Lethal Factor (LF) PA: needed for binding and cell entry EF: mimics adenylate cyclase ==> increased cAMP LF: protease that inhibits cell-signaling ==> apoptosis

Answer 6

bioterrorism or wool-sorting disease (from animal contact) **Inhaled**: - clinical manifestations: fever, chills, sweats, GI symptoms, headache, malaise, NO CORYZA (runny nose) - widened mediastinum **Cutaneous**: - eschar: dry, dark dead skin **GI**: - nausea, vomiting, fevers 1-5 days after eating infected meat ## Footnote Viking standing in middle of burnt fire

Answer 7

doxycycline, fluoroquinolone (ciprofloxacin), amoxicillin ## Footnote flower and bicycle wheel on Viking ship

Answer 8

- gram-positive rod - spore-forming, motile - **heat-stable enterotoxin (cereulide)**: nausea and vomiting within hours of eating (reheated rice) - **heat-labile enterotoxin**: diarrhea, symptoms arrive a little later (6-8hr) ## Footnote Viking eating rice and throwing up

Answer 9

- gram positive rod - spore-forming - obligate anaerobe

Answer 10

- nervous system disorder characterized by muscle spasms due to blocking of inhibitory transmitter release (continuous stimulation) - glycine-producing Renshaw cells preferentially targeted - lockjaw (rismus): intense, painful spasms of masseter muscles - opisthotonus: spasm of spinal extensors

Answer 11

- halt toxin production, neutralize unbound toxin, airway protection, control muscle spasms - antimicrobials play minor role - active immunity through vaccination only: 3 doses of tetanus and diphtheria toxoid immediately upon diagnosis

Answer 12

anaerobic heat-resistant spores: germinate in canned foods - robots made of cans neurotoxin: most potent known bacterial toxin ==> **neuroparalytic syndrome** affecting peripheral nervous system only (cannot cross blood-brain barrier), descending paralysis as toxin blocks release of ACh from vesicles (stimulation blocked) - robots struggling to keep upright after ingesting raw honey, babies lack gut flora that can outcompete C. botulinum ==> floppy baby syndrome - robot pouring honey all over baby robot iatrogenic (within healthcare setting) botulsim: unlicensed Botox

Answer 13

- prompt intubation with mechanical ventilation - antitoxin: equine serum heptavalent botulism antitoxin or human-derived botulism immune globulin

Answer 14

found in soil - knocked over dirt **alpha-toxin**: phospholipase (**lecithinase**) that breaks down tissue and cell membranes ==> myonecrosis (gas gangrene: gas produced under tissue and has cracking sound on palpation) - gas leaking out of motorcycle - alpha flag **exotoxin**: heat-resistant spores in food reproduce in gut ==> release exotoxin ==> slow onset diarrheal illness - slow sign IV **penicillin G** - woman holding pencil "perfringens perforates a gangrenous leg"

Answer 15

gram positive rod

Answer 16

- gram-positive, non-spore forming - club-shaped bacteria - mycolic acid on cell wall - NOT acid fast - cystine-tellurite agar (lipid supplemented)

Answer 17

**diphtheria toxin**: inhibits protein synthesis via ADP-ribosylation of elongation factor (EF-2) ==> cell death - man playing accordian wearing bow tie **pseudomembrane**: fibrinous exudate found in oral pharynx that contains dead tissue, inflammatory cells, bacteria - kids eating grey cotton candy wrapped in plastic wrap **airway obstruction, lymphopathy**: thickening of the neck - thick bull's neck **myocarditis**: arrhythmias, heart block; lethal - heart-shaped cape **peripheral and cranial neuropathies**: damaged myelin sheaths; top-down symptoms that usually resolve - sausage-eating man

Answer 18

treatment: penicillin - score keeper with pencil natural infection doesn't result in protective immunity; recovered patients still need vaccine (DTaP, toxoid vaccine)

Answer 19

- gram positive rod - only gram(+) to produce lipopolysaccharide (LPS) endotoxin <- fat Santa - non-branching - individual rods or short chains - motile at cold temperatures: tumbling motility - intracellularly, uses actin polymerization to spread from cell to cell (rocket tails) without having to go outside cells

Answer 20

transmitted in food, even refrigerated food like milk and cheese - Santa eating milk and cheese high risk: neonates, elderly, pregnancy, those with severe defects in cell-mediated immunity - pregnant mom and baby health adults: febrile diarrhea immunocompromised/elderly: bacteremia with or without CNS infection pregnant women: can result in spontaneous abortion neonates: meningitis

Answer 21

- gram positive rods - branching filaments (tree branches) - obligate anaerobes - NOT acid fast - part of normal oral flora (also GI, GU tracts)

Answer 22

infection associated with dental caries/extractions or gingival disease ==> cervical facies atinomyces infection - soldier with bandage around head does NOT respect anatomic borders, so can form sinus tracts (channel from source to skin) - drain with water yellow sulfur granules composed of bacteria, tissue debris, neutrophils - yellow rocks on ground treatment: **penicillin**, erythromycin, clindamycin - solder writing with pencil

Answer 23

- gram positive rod - branching filaments - cell wall has mycolic acid (similar to Mycobacteria, but a lot less) - weakly acid fast staining (Ziehl-Neelsen stain + carbol fuchsin), decolorized by hydrochloric acid - catalase positive - exogenous flora found in soil ## Footnote cowboys playing cards

Answer 24

**risk factor:** defects in cell-mediated immunity (transplant, HIV/AIDS, underlying lung disease) - cowboy leaning on cane **clinical symptoms:** cavitary lung lesions (cough, SOB); pneumonia - bullet hitting cowboy's chest and denting the star brain abscess (headache, fever, focal neurologic deficits) - bullet shooting a hole through his hat cutaneous indurated (hard) lesions and inflammation <- immunocompromised people can get cutaneous disease alone following trauma - cowprint on cowboy with redness

Answer 25

**trimethoprim-sulfamethoxazole** - eggs on the counter: treat with sulfonamides prolonged therapy: 12mo

Answer 26

lipopolysaccharide (LPS)

Answer 27

gram-negative diplococci, often intracellular - red theme - double handcuffs aerobic, oxidase positive - blue ring carbohydrate utilization pattern: N. meningitidis = glucose(+) and maltose(+) N. gonnorrhoeae = glucose(+) and maltose(-) - "MeninGococci ferment Maltose and Glucose" grows on chocolate agar, inhibited on blood agar - detective holding chocolate bar Thayer-Martin agar: selective agar with vancomycin, polymixin, nystatin - Vice city Private Nvestigator (VPN) ## Footnote Noir series

Answer 28

- encapsulated; capsule is primary virulence factor - primarily colonizes nasopharynx - easily spread in areas with a lot of people via respiratory droplets - 10% mortality even in healthy patients - risk factors: complement deficiency (MAC deficiency), asplenia (lack of spleen, sickle cell disease), history of respiratory tract infections, preterm birth - wide range of illness: transient fever, pneumonia, **meningitis**, **meningococcemia**, septic shock, disseminated intravascular coagulation (DIC) **Meningococcal meningitis:** headache, nuchal rigidity, photophobia, petechial rash, hemorrhage on mucous membranes of soft palate/conjunctiva **Shock & DIC:** tachycardia, hypotension, cold extremeties, adrenal infarction, bleeding occurring from skin/mucous membranes/GI tract/respiratory tract ## Footnote college dorm murder scene

Answer 29

Drug of choice is **ceftriaxone**, can also use IV penicillin G - firefighter with 3 axes patients placed in droplet isolation, continued for 24hr after antibiotics close contacts will need rifampin - police with rifle holding back crowd There IS a vaccine for N. meningitidis ## Footnote mortality is still high despite treatment

Answer 30

- not encapsulated - gonococcal infection can be localized (urethritis), localized invasive (pelvic inflammatory disease), or systemic (disseminated gonococcal infection) - **pelvic inflammatory disease**: inflammatory diseases of upper female genital tract (endometritis, salpingitis, etc) - diganose with PCR/NAT **Treatment**: ceftriaxone - statue with 3 axes

Answer 31

3 species pathogenic to humans: 1) **Chlamydia trachomatis** 2) Chlamydophila psittaci 3) Chlamydophila pneumoniae - obligate intracellular organisms (unable to make their own ATP) - lack peptidoglycan layer, lacks muramic acid - cannot grow on artificial media so PCR/NAT is needed for diagnosis - 2 developmental phases: **elementary body** (infectious form), **reticulate body** (replicative, non-infectious form) **Elementary body**: "Enfectious and Enters cell via Endocytosis, transforms into reticulate body"; extracellular **Reticulate body**: "Replicates in cell by fission; Reorganizes into elementary bodies"; intracellular

Answer 32

**Trachoma biovars** - A, B, Ba, C serovar - **D-K** serovar: Urogenital tract disease (urethritis) **LGV biovars** - **L1, L2, L3** serovar: lymphogranuloma venereum affects mucous membranes: urethra, endocervix, endometrium fallopian tubes, anorectum, respiratory tract, conjunctivae clinical manifestations due to direct **destruction of cells during replication**, post-inflammatory cytokine response infection does not confer long-lasting immunity due to antigenic variation

Answer 33

- caused by LGV serovars L1, L2, L3 - organisms gain access through small abrasions/lacerations - **primary lesion**: small, painless vesicular lesion that ulcerates; lesion heals in 3-5 days - **second stage**: 1-4wk after primary lesion; enlarged lymph nodes become painful buboes that can rupture and drain **Treatment**: doxycycline (21 days) - erythromycin in pregnant women

Answer 34

- caused by serovars A, B, Ba, C - leading cause of preventable blindness, commonly occurs in children - chronic/repeated infection ==> inflammation and follicle formation of entire conjuctiva (turning in of eyelids, scarring, ulceration, blood vessel formation in cornea) ==> blindness

Answer 35

- most caused by serovars D-K - most common STD reported in USA - dual infection with Neisseria gonorrhea is common - pelvic inflammatory disease, cervicitis, endometritis, urethritis - reactive arthritis: triggered by urethritis, conjunctivitis, polyarthritis **Treatment**: doxycycline (7 days) - bicycle wheel as wheel of ship

Answer 36

causes psittacocis ("parrot fever") and atypical pneumonia

Answer 37

causes atypical pneumonia

Answer 38

gram-negative coccobacillus - pink candy machine shaped like a bullet chocolate agar: Factor V (NAD+) and X (hematin/hemin), which are found in hemolyzed blood - chocolate shop, 5 and 10 cent signs - "hemophilic" influenzae - can also be grown with Staph aureus, which is beta hemolytic and promotes release of factor V **virulence factors:** capsular polysaccharide IgA protease: cleaves mucosal IgA

Answer 39

epiglottis (H. influenzae type b) - coughing child with red tongue non-typeable (no capsule): otitis media - child sticking fingers in his ears pneumonia - child coughing + aerosol spray **Treatment**: ceftriaxone and rifampin for close contacts - coughing boy has 3 axes - unaffected boy has rifle **Vaccine**: capsular polysaccharide conjugated to a protein (only for type b)

Answer 40

- encapsulated gram-negative rod - obligate aerobe - oxidase positive (blue ring) - non-lactose fermenting - thrives in hot environments - blue-green culture - **pyocyanin**: blue-green pigment that acts as a virulence factor, helps with biofilm formation, generates ROS - **pyoveridine**: blue-green pigment that is an iron-chelating molecule, acts as a virulence factor, helps with biofilm formation - **exotoxin A**: inactivates elongation factor 2 (EF-2) ==> inhibition of protein synthesis ==> cell death (accordion player) - **endotoxin**: fever and shock - **phospholipase C**: helps degrade cell membranes - cystic fibrosis

Answer 41

- **nosocomial pneumonia and UTI**: hospital infections (nurse coughing, chamber pot) - bacteremia in hospitalized patients - chronic pnuemonias in patients with **cystic fibrosis** - skin infections: burn wound infections, hot tub folliculitis

Answer 42

- Escherichia coli: UTIs - Klebsiella spp.: pneumonia

Answer 43

- gram-negative - fast lactose-fermenter - MacConkey agar (contains lactose); E. coli grows pink - green sheen on Eosin-methylene blue (EMB) agar <- stains for gram(-) - facultative anaerobic, oxidase negative - encapsulated - **P Fimbriae (aka P pili)**: adhere to urogenital epithelium - **K capsule**: capsular polysaccharide that inhibits phagocytosis - **Lipid A and O-antigen of lipopolysaccharide (LPS)** endotoxin: shock and fever

Answer 44

- gram-negative - fast lactose-fermenter - grows pink on MacConkey agar; thick and mucoid - natural flora of GI tract - **capsular polysaccharide**: thick capsule reflected in very mucoid colonies seen on agar - can cause pneumonia

Answer 45

- aerobic - weakly gram-positive bacilli - acid-fast (Ziehl-Neelsen stain) - gold standard is culture: solid (Lowenstein Jensen agar) and liquid media, but takes 6-8wk to culture - mycolic acid cell wall (hydrophobic, lipid rich) - patient's cell-mediated immunity is key to prognosis: TH1 response, activation of CD4+ T-cells, secretion of INF-y, macrophage/CD8+ cell response

Answer 46

**virulence factors:** **cord factor** (trehalose dimycolate) and **mycolic acid glycolipids** elicit granuloma formation by increasing TNF-a (activates other alveolar macrophages) ==> CD4+ T-cells come help, forming collar around macrophages ==> sulfatides prevent phagolysosome fusion ==> ceseating granuloma formation - cowboy lasso inhalation of M. tuberculosis into lungs results in **latent infection** and disease onset many years later (**reactivation**) - **latent TB**: infection without any symptoms = 90% of pts - **reactivation disease**: cavitary lung lesion in upper portion of lung **clinical findings:** - fear, weight loss, anorexia, hemoptysis (coughing up blood), drenching night sweats

Answer 47

**airborne isolation**: N95 mask - suspected TB: at lest 3 consecutive sputum specimens collected in 8-24hr intervals **PPD test**: purified protein derivative skin test - false negatives due to immunosuppressive drugs or immunocompromised pts - false positives due to hx of BCG vaccine **Quantiferon TB Gold In-Tube test**/Interferon Gamma Release Assay (IGRA): single blood test, no cross-reactivity with other Mycobacteria - antigen provided in tube ==> pt's antigen-presenting cells process antigen ==> APC presents to antigen specific T-cell ==> T-cell produces IFN-y - detection based on IFN-y amounts - only tests for latent TB infection, does NOT say if pt has active infection **Bacillus Calmette Guerin (BCG) vaccine**: - attenuated M. bovis - used in countries where TB is endemic **Treatment:** 4 drugs for 2 months, then 2 drugs for 4 months - RIPE: Rifampin (RIF), Isoniazid (INH), Pyrazinamide (PZA), Ethambutol (EMB)

Answer 48

- affects the skin, peripheral nerves, upper respiratory tract mucosa, eyes - consider in patients with cutaneous lesions + enlarged nerves/sensory loss - not very transmissible - inhalation of M. leprae from respiratory drops - armadillo/Mangabey monkey contact - diagnosis: skin biopsy of skin lesion shows acid-fast bacilli (AFB); PCR **Spectrum of leprosy**: influenced largely by patient's immune status - high cell mediated immunity = tuberculoid disease, paucibacillary leprosy (low AFB load), Th1 response - low cell mediated immunity = lepromatous leprosy, multibacillary leprosy (high AFB load), Th2 response (inappropriate)

Answer 49

M. avium + M. intracellulare - asymptomatic colonization, leads to enlarged lymph nodes (lymphadenitis) - **disseminated disease in AIDS patients**: most common mycobacterial disease in USA, diagnosis made with blood culture (CD4 < 50cells/mm3); chronic condition (diarrhea, fevers, anemia) - **AIDS-defining illness** - pulmonary disease in immunocompetent patients

Answer 50

- tuberculosis-like symptoms in fish - cutaneous lesions

Answer 51

- Treponema pallidum (syphilis) - Borrelia (Lyme disease) - Leptospira (leptospirosis, Weil disease) technically gram-negative, but very weak gram-negative stain and not truly considered gram-negative organisms

Answer 52

**Lyme disease** from hard ticks, **ixodes** - early Lyme: bulls-eye skin lesion develops at tick bite, called Erythema Chronicum Migrans (ECM) - late disease: neurologic signs (meningitis, Bell's palsy), monoarticular arthritis, cardiac Also causes relapsing fever from body louse or soft ticks; relapsing due to antigenic variation **Treatment**: doxycycline - treat if high clinical suspicion ## Footnote spiraly wood shavings from arrow

Answer 53

- infection via urine-contaminated water and animal exposure (rodents, dogs, domestic/wild animals) - severe headaches, flu-like illness, aseptic meningitis, scleral icterus (yellow sclera) - Weil's disease (severe disease): vascular collapse, thrombocytopenia, hemorrhage, liver/kidney failure **Treatment:** penicillin or doxycycline ## Footnote coiled ankle strap on surfboard; yellow sea (pee)

Answer 54

**Syphilis:** Primary syphilis: - painless chancre - diagnose with dark-field microscopy Secondary syphilis: - disseminated disease: fever, lymphadenopathy (swollen lymphs), maculopapular rash, condyloma lata (painless wart-like lesions on genitals) - diagnose with nontrepenomal / treponemal tests Tertiary syphilis: - gummas (chronic granulomas of skin), aortitis, neurosyphilis - diagnose with CSF examination (lumbar puncture) Latent syphilis: - no clinical symptoms - diagnose with CSF examination Congenital syphilis: - early: hepatomegaly, nasal discharge (snuffles), skeletal abnormalities, rash, lymphadenopathy - late: saddle nose, sensorineural hearing loss, Hutchinson's teeth/incisors, mulberry molars, saber shins **Treatment:** penicillin G ## Footnote spiral galaxy at the Pallidum observatory

Answer 55

Dark-field microscopy: - only for primary syphilis dx Non-treponemal (non-specific) testing: - detects anti-cardiolipin antibodies - used to monitor response to therapy - can be falsely negative early or late in disease - false positive with other conditions: (pregnancy, HIV, autoimmune disease, recent immunization, acute febrile illness) - VDRL - RPR Treponemal (specific) testing: - detect antibodies that specifically target T pallidum - very specific, positive test remains for life - TP-EIA - FTA - TP-PA - MHA-TP

Answer 56

Rickettsial diseases: - **Rickettsia rickettsii** (Rocky Mountain Spotted Fever) - Rickettsia akari (pox) from mites - Rickettsia typhi (typhus) from fleas - Rickettsia prowazekii (typhus) from body lice - Ehrlichia chaffeensis (ehrlichiosis) - Anaplasma phagocytophilum (anaplasmosis) - Coxiella burnetti (Q fever) Other: - Yersinia pestis (bubonic plague) - Bartonella spp (cat-scratch disease) - Bartonella quintana / B. henselae (regional lymphadenopathy) - Francisella tularensis (tularemia)

Answer 57

Rocky Mountain spotted fever - dog tick and wood tick - fever, severe headache, myalgias, rashes on hands/wrists/feet that move to trunk - severe: pulmonary and renal failure, cardiac and neurologic damage - 10-25% fatality without treatment **Treatment:** doxycycline

Answer 58

Ehrlichia chaffeensis - Lone star tick - ehrlichiosis: YES rash, leukopenia, high fever, headache - morulae (berry-like inclusions in cytoplasm) in monocytes - Central-South USA Anaplasma phagocytophilum - Ixodes tick - high fever, headache, NO rash - morulae in granulocytes **Treatment**: doxycycline

Answer 59

Q fever - infected via aerosols from cattle/sheep amniotic fluids or contaminated milk - replicates within vacuoles - most cases are asymptomatic - symptoms: mild, flu-like symptoms OR pneumonia - Chronic Q fever: subacute endocarditis in those with underlying valvular heart disease or immunosuppression **Treatment:** doxycycline

Answer 60

Bubonic plague - Western US with prairie dogs, squireels, rodents; transmitted through fleas - fevers, headaches, myalgias, painful swollen lymph nodes (buboes) - diagnosis: bacteria stain bipolar (safety pin appearance)

Answer 61

Bartonella quintana - non-zoonotic pathogen - transmitted by humans Bartonella henselae - zoonotic - cat-scratch disease - regional lymphadenopathy

Answer 62

Tularemia - rabbits, ticks - ulceroglandular: fever, single ulcer with central eschar at site of tick bite **Treatment:** streptomycin

Bacteria Flashcards

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