Bacteria Flashcards

Question

Neisseria common characteristics

Answer 1

Gram(-) diplococci, ferment glucose, oxidase(+), produce IgA protease, grown on chocolate agar or VPN (Thayer Martin) agar pillus virulence factor- antigenic variation patients with C5-9 deficiency are at higher risk of infection

Answer 2

often intracellular w/in PMNs Not encapsulated, no maltose fermentation No vaccine due to antigenic variation of pilis protiens sexually or **perinatally (prevent with erythromycin** ointment) transmitted Causes: **gonorrhea (white purulent discharge+ often chlamydia coinfection), septic arthritis** - knee, asymmetric, **PID, Fitz-Hugh-Curtis** syndrome (PID infection spreads to peritonium)- "violin-string" adhesions to liver, **early onset conjunctivitis in neonates** Treatment**: ceftriazone + azithromycin or doxycycline (chlamydial infection risk)**

Answer 3

Encapsulated, ferments maltose **Vaccine** of polysaccharide capsules A, C, D (**B not available**) Transmitted via respiratroy and oral secretions, spread in **close quarters** (college) **Sickle cell and asplenic patients at higher risk** of infection (can't kill encapsulated organisms) LOS envelope causes inflammation -\> _increase permiability of capillaries_ - \> **petechial rash (thrombocytopenia)** -\> can lead to **DIC** - \> hypovolemia (shock) -\> poor perfusion of adrenals -\> **Waterhouse-Friderichsen syndrome** **Treatment: ceftriaxone or penicillin G, rifampin prophylaxis for close contacts**

Answer 4

gram(-) coccobacillary rod, cultured on chocolate agar (has factors V and X) or can be grown with S. aureus (provides V through hemolysis) Capsule: immunogenic and composed of polyribosyl-ribitol-phosphate (PRP) -\> antibodies to PRP facilitate complement-dependent phagocytosis Increased risk with sickle cell, asplenic patients Causes: **epiglottitis ("cherry red"** in children, "thumbprint" sign on xray), meningitis (mostly in children), Otitis media, Pneumonia Treat **mucosal infections: amoxicillin +/- clavulanate**, **meningitis: ceftriaxone**, close contact **prophylaxis: rifampin** Vaccine: type b capsular polysaccharide (PRP) conjugated to diphtheria or tetanus toxoid: given btwn 2-18mo age

Answer 5

gram(-) rod, poor gram staining-\> **silver stain**, grow on **charcoal culture w Fe and cysteine** Transmission via aerosols - **environmental water source** (AC, hot water tanks) **Diagnosis: urine antigen** **Labs: Hyponatremia (low sodium)** **_Legionnaires' disease_** - usually in smokers, severe pneumonia (often unilateral and lobar), high fever, GI and CNS symptoms --\> **pneumonia + diarrhea highly suggestive** _Pontiac fever_ - mild flu symptoms, self limiting **Treatment: macrolide or quinolone**

Answer 6

Gram(-) bacilli, **aerobic**, **encapsulated,** motile, oxidase (+), non-lactose fermenting, produces **pyocyanin (blue-green pigment), grape-like odor** Produces endotoxin (fever, shock) and exotoxin A (inactivates EF-2 via ribosylation, same mech as diptheria toxin) Found in water -\> hot tub folliculitis Associated with infection in **burn victims**, mucoid capsule may contribute to chronic **pneumonia in CF patients** due to biofilm formation **P**neumonia (noscomial, chronic in CF patients) **S**epsis - bacteremia can cause **ecthyma gangrenosum,** rapidly progressive necrotic cutaneous lesions (usually in immunocompromised) Otitis **E**xterna (swimmer's ear) **U**TIs (nosocomal) IV **D**rug use, **D**iabetes -\> **O**steomyelitis (puncture wounds)

Answer 7

Extended-spectrum beta-lactams: **piperacillin**, ticarcillin, cefepime Carbapenems: imipenem, meropenem monobactams: aztreonam **fluoroquinolones: ciprofloxacin** **aminoglycosides: gentamicin, toramycin** If multi-drug resistant: colistin, polymyxin B

Answer 8

gram(-) rod, lactose fermenting (pink on McConkey agar) virulence factors: fimbriae - cystitis and pyelonephritis K capsule - pneumonia, neonatal meningitis LPS endotoxin - septic shock

Answer 9

Mechanism: invades intestinal mucosa and causes necrosis and inflammation (similar to shigella) Presentation: invasive, dysentery (bloody diarrhea)

Answer 10

Mechanism: produces **heat-labile** (increases c**A**MP-\> increase Cl- secretion), **heat-stable** (increases c**G**MP-\> decrease resorption of NaCl) enterotoxins. No inflammation or invasion Presentation: Traveler's diarrhea (watery)

Answer 11

Mechanism: no toxin produced. Adheres to apical surface, flattens villi, prevents absorption Presnetation: diarrhea (in children-E**P**EC **P**ediatrics)

Answer 12

**O157:H7** most common serotype in US, **does NOT ferment sorbitol** (different from other E.coli) also called STEC (shiga toxin-producing E. coli) Caused by eating undercooked meat **Shiga-like toxin** -\> hemolysis (schistocytes on blood smear), plt consumption (thrombocytopenia), decreased renal blood flow (acute renal failure); toxin causes necrosis and inflammation-\> **dysentery** (bloody diarrhea) **HUS (hemolytic-uremic syndrome)**: anemia, thrombocytopenia, acute renal failure (microthrombi form on damaged endothelium)

Answer 13

**gram(-), lactose fermenting** (pink on McConkey), urease (+), mucoid colonies from abundant polysaccharide capsules, _NOT motile_ intestinal flora -\> **lobar pneumonia in alcoholics and diabetics when aspirated, abscess** in lungs and liver (cavitary lesion on CT) **Dark red "current jelly" sputum** cause of nosocomial pnuemonia and UTIs Treatment: carbapenems

Answer 14

gram(-) comma-shaped, oxidase(+), grows at 42C (hot like campfire) Fecal-oral transmission through person-person, ingestion of poultry, meat, unpasteurized milk, or contact with infected animals \*major cause of bloody diarrhea, especially children Invasive -\> can cause reactive arthritis (Reiter's syndrome) Guillan-Barre syndrome: autoimmune response -\> demyelination causes ascending paralysis

Answer 15

Common antecedent to **Guillain-Barre syndrome** (ascending paralysis from autoimmune response-\> demyelination) and **reactive arthritis**

Answer 16

gram(-) bacilli, encapsulated, non-latose fermenting, oxidase(-), **H2S(+)**-\>black colonies on Hektoen agar, **motile (flagella)** Reservoir: **humans ONLY** (differentiate from salmonella spp which also has animal reservoirs such as poultry, pets, turtles) stays in gallbladder in carrier Spread: **disseminate hematogenously** (similar to other salmonella spp.), facultative intracellular in macrophages Virulence factors: Endotoxin and Vi capsule Infectious dose **(ID50) is High**, need large inoculum bc **acid-labile** Vaccine: **oral vaccine contains live attenuated** s. typhi, **IM vaccine contains Vi capsular** polysaccharide **Typhoid fever:** _rose spots on abdomen_, constipation, followed by "pea soup" diarrhea, abdominal pain, fever; Widespread dissemination can cause HSM and GI bleeding. Severe cases can result in transmural necrosis -\> intestinal perforation; _#1 cause of osteomyelitis in sickle cell_ **Treat with ceftriaxone or fluoroquinolone** Antibiotics prolong duration of fecal excretion Immune response: primarily monocytes, PMNs in disseminated disease GI: constipation, followed by diarrhea

Answer 17

gram(-) bacilli, non-latose fermenting, encapsulated, oxidase(-), **H2S(+)-**\>black colonies on Hektoen agar, **motile (flagella)** Reservoir: humans and **animals such as poultry, pets, turtles** Spread: hematogenously Virulence factors: endotoxin **ID50: High, acid-labile** Antibiotics prolong duration of fecal excretion GI: **Gastroenteritis- Bloody diarrhea** Immune response: facultative intracellular in macrophages, PMNs in disseminated disease **NO VACCINE**

Answer 18

gram(-) bacilli, non-lactose fermenting, oxidase (-), **green colonies on Hektoen agar (No H2S production), immotile** Most severe--\> least severe: Shigella dysenteriae, S. flexneri, S. boydii, S. sonnei (least toxin produced) Virulence factors**: Endotoxin, Shiga toxin (enterotoxin) -** binds to 60s ribosomal subunit \*Type 3 secretion system\* **ID50: low, acid stable** (different from salmonella) **Antibiotics shorten duration of fecal excretion** (different from salmonella) Immune response: PMNs GI: inflammatory bloody diarrhea **HUS (more commonly from E.coli) common in children \<10yo**, thrombocytopenia, anemia, acute renal failure NO Vaccine

Answer 19

Gram(-) comma shaped, oxidase(+), grows in alkaline media Does not invade**, uses fimbrae to attach to intestinal wall** **Enterotoxin permanently activates Gs**-\> i**ncrease cAMP** -\> secretion of water into lumen --\> **rice water diarrhea** Treatment: **oral rehydration**

Answer 20

gram (-), oxidase (-), produces H2S, "bipolar" staining, encapsulated Reservior: praire dogs (in US) **Transmission: pet feces (puppies) \*toddlers commonly affected**, contaminated milk or pork \*cold resistant\* Clinical features: causes **acute bloody diarrhea** or **pseudoappendicitis** (RLQ pain due to mesenteric adenitis or terminal ileitis), **buboes** on skin Treatment: **streptomycin w tetracycline** Killed vaccine

Answer 21

peptic ulcers, gastric adenocarcinoma, MALT lymphoma

Answer 22

CHaracteristics: curved (more helical) gram (-) rod, catalase (+), oxidase (+), urease (+) -\> can use **urea breath test or fecal ag test for diagnosis** **Causes: gasritis and peptic ulcers, especially duodenal** Treatment: triple therapy**- PPI + clarithromycin + amoxicillin (or metronidazole** if allergic to penicillin**)**

Answer 23

gram(-), urease(+), **fishy odor, swarming motility** when plated may cause **UTIs**, alkaline environment can form **struvite** stones -\> forms **staghorn caliculi** treat with **sulfonamides**

Answer 24

Spirochete- spiral or "?" shaped Found in **water contaminated with animal urine**, prevalent among **surfers** and in **tropics** **Leptospirosis -** fever, flu-like symptoms**, myalgias in calves, jaundice, photophobia with conjunctival suffusion** (erythema _w/o exudate)_ **Weil disease** (icterohemorrhagic leptospirosis) - severe form causes kidney and liver dysfxn, **jaundice and azotemia, fever, hemorrhage, anemia**

Answer 25

Reservoir= mouse, Transmitted by Ixodes deer tick, common in NE United States

Answer 26

Characteristics: Wright and Giemsa stain, spirochete Symptoms: Stage 1: initial- flu-like symptoms and **erythema chronicum migrans** (Bull's eye rash) *not painful or pruritic!* Stage 2: myocarditis-(AV nodal block) +/- facial nerve palsy (Bells palsy) Stage 3: **monoarthritis** (large joints), **migratory polyarthritis**, neurologic (cognitive effects, meningitis, **facial nerve palsy**, polyneuropathy) Treatment: **doxycycline** for early infection, **ceftriaxone** for later presentations

Answer 27

spirochete causing syphilis - STD, treat with penicillin

Answer 28

genitals- painless chancre few weeks after inoculation (ischemic necrosis, takes out nerves -\> painless)

Answer 29

**Dark-field microscopy** to visualize treponemes in chancre fluid **Serologic testing: VDRL or RPR**- detects nonspecific Ab that reacts w beef cardiolipin. Sensitive but NOT specific; is (+) in 80%, **false positives** with viral infection (mono, hepatitis), drugs, RF, lupus and leprosy Confirm diagnosis with _specific test-_ **FTA-ABS**

Answer 30

Systemic symptoms: disseminated disease w constitutional symptoms, **maculopapular rash** (weeks to months after infection) **including palms and soles,** **condylomata lata** (wart-like white lesions on genitals) _After scondary syphilis -\> Latent syphilis_ (+ serology w/o symptoms)

Answer 31

**Gummas** (chronic granulomas), **aortitis**'tree-barking' appearance (AAA, vasa vasorum destruction) **neurosyphilis**-\> **_Tabes dorsalis_**-\> demyelination of dorsal spinal column -\> loss of propioception, vibration and discriminatory touch, **Argyll Robertson pupil** (accommodation but not reactive to light, aka "_prostitute's pupil_") Signs: broad-based ataxia, (+) Romberg, Charcot joint (neuropathic arthropathy), stroke w/o HTN For neurosyphilis: test spinal fluid with VDRL and PCR

Answer 32

Presentation: facial abnormalities like **rhagades** (linear scares at angle of mouth), **snuffles** (nasal discharge), **saddle nose**, **notched (Hutchinson teeth)**, mulberry molars, short maxilla, **saber shins**, **CN VIII deafness** Prevention: treat mother early in pregnancy, **placental transmission usually after 1st trimester**

Answer 33

Treat with **penicillin**, if tertiary-\> IV penicillin x3 wks **_Jarisch-Herxheimer reaction_** after antibiotics is very common! **Flu-like syndrome** (fever, chills, HA, myalgia) due to _killed spirochetes releasing endotoxins_: LPS -\> increased cytokines released -\> flu symptoms

Answer 34

gram-variable rod (+ or - staining) Normal flora: lactobacilli, if decrease normal flora -\> promotes overgrowth of gardeneralla **_Bacterial vaginosis_** - **gray discharge** w **fishy smell, non-painful** (vaginitis is painful) Histology: + **Clue cells** -\> vag epithelial cells covered with gardnerella bacteria Infection when pH \>4.5 **Amine whiff test**- mix discharge w KOH -\> increase odor Associated w sexual activity, but NOT transmitted sexually **Treatment: metronidazole or clindamycin**

Answer 35

Lyme disease, anaplasmosis, babesiosis

Answer 36

Erlichiosis

Answer 37

Tularemia, Rocky Mountain spotted fever

Answer 38

Warthrin Starry stain **Cat scratch disease** (in healthy patients): axilary lymphadenitis **Bacillary angiomatosis (immunocompromised),** red raised vascular lesions**,** also transmitted via cat scratches **Treatment: macrolides**

Answer 39

Facultative intracellular, gram(-), prevent phagocytic fusion -\> can travel into multiple reticuloendothelial organs Transmission via **ingestion of unpasteurized dairy** or direct **contact w pigs or cows** Brucellosis/ **undulant fever** - splenic and liver involvement, osteomyelitis (chronic infection) Treatment: doxycycline +/- rifampin adjunctive therapy

Answer 40

Anaplasmosis, vector is Ixodes tick Granulocytes w morulae in cytosol **Treatment: doxycycline**

Answer 41

Transmitted by **louse**, causes **relapsing fever**

Answer 42

**psittacosis** from parrots and other birds- pneumonia like symptoms

Answer 43

Gram (-), obligate intracellular Transmitted by **spores** in animal feces, **aerosols of cattle/sheep or amniotic fluid** **Q fever** - presents **like pneumonia, HA, fever, HEPATITIS**, most common cause of **culture (-) endocarditis** _NO RASH, NO VECTOR_ **Treatment: usually self-limiting, doxycycline**

Answer 44

Transmitted by **lone star tick (ambylomma**) Causes **Erlichiosis**: monocytes w/ morulae inclusions. leukopenia, thrombocytopenia **Treatment: doxycycline**

Answer 45

Gram(-) coccobacilli (radish shaped), facultative intracellular Transmitted by **dermacentor ticks**, **rabbits (main reservoir)**, deer fly, can be aresolized -\> have to report to CDC since can be bio weapon **Tularemia- painful ulcer at site of infection**, goes into macrophages and travels through lymph system -\> regional **LAD**, **granulomas** **w caseating necrosis** in reticuloendothelial system (lymph nodes) **Treatment: aminoglycosides (streptomycin)**

Answer 46

Gram(-), Grows on 5% sheep blood agar, oxidase and catalase (+), encapsulated, bipolar 'safety pin' staining (like yersinia) **Animal bites (cats and dogs)** Causes: **cellulitis** in first 24 hours, **osteomyelitis** if infection spreads Treatment: penicillin

Answer 47

Encapsulated, cold tolerant Transmitted by fleas (rats and praire dog reservoirs) Causes plague-\> buboes swollen tender lymph nodes. Once in blood stream can cause abscesses, DIC from endotoxin and can cause necrosis (black death) Virulence factors: exotoxins, Type III secretion system-Yops: yersinia-associated outer proteins -\> cause PMN and macrophage dysfunction by inhibiting phagocytosis and cytokine production -\> can replicate and spread Treatment: aminoglyoside (streptomycin), tetracycline Killed vaccine

Answer 48

Obligate intracellular, weakly gram staining Transmitted by **human body louse** (scratching of feces into blood) At risk: military camp (close contact w/ poor hygiene) causes **Epidemic Typhus (widespread outbreak)** **Myalgia and arthralgia, pneumonia, encephalitis** (dizziness and confusion)**, coma if severe** **Rash** starts centrally and spreads out**; _spares_ head, palms and soles** **Treatment: doxycycline**

Answer 49

Obligate intracellular (lack CoA and NAD+), weakly gram staining Transmitted by bite from **Dermacentor (dog tick)**, occurs in South Atlantic states (especially **NC**) **Rocky Mountain Spotted Fever** - rash starts weeks after infection; **rash** starts at wrists and ankles, spreads to trunk, **palms and soles, HA, fever, myalgias** **Treatment: doxyclycline**

Answer 50

Transmitted by fleas causes **Endemic typhus - rash starts on trunks** and moves outward, sparing palms and soles **Treatment: doxycycline**

Answer 51

**C**oxsackievirus **A** infection (hand, foot, mouth disease) **R**ocky Mountain spotted fever Secondary **S**yphilis "drive **CARS** with **palms** and **soles"**

Answer 52

**Obligate intracellular** organisms (cannot make own ATP), cell wall lacks muramic acid--\> beta-lactams are not very effective, have 2 forms: _**E**lementary body_ (small, dense) is "**E**nfectious" and **E**nters cell via **E**ndocytosis; transforms into reticulate body _**R**eticulate body_ **R**eplicates in cell by fission, **R**eorganizes into elementary bodies **Diagnosis: cytoplasmic inclusion**s on **Giemsa** or **fluorescent Ab-stained smear, NAAT (nucleic acid amplicication test)**

Answer 53

Atypical pneumonia, transmitted via aerosoles Chlamod. psittaci: pnuemonia transmitted by birds Treatment : doxycycline 1st line, macrolides 2nd line

Answer 54

Commonly co-infected w/ gonnhorea **A,B,C**: **Trachoma**: Hand to eye contact, **C**hronic infection causes **blindness** due to follicular conjunctivitis in **Africa** **D-K: Urethritis/PID**, ectopic pregnancy, **neonatal** **pneumonia** (staccato cough) w eoinophilia, **_neonatal_** **conjunctivitis** (acquired through birth canal passage, longer time frame than gonorrhea) **L1-3: Lymphogranuloma venereum** - small, painless ulcers on genitals-\> weeks/mos later: swollen, **painful inguinal lymph nodes** that ulcerate (buboes) _Complications: reactive arthritis_ (sacroiliac joint in knee), uveitis and urethritis (Reiter syndrome)- 'cant see cant pee cant climb a tree' **Treat w/ azithromycin (macrolide) or doxycycline (tetracycline) + ceftriaxone (gonorrhea co-infection)**

Answer 55

No cell wall (penicillin ineffective), not seen on gram stain, pleomorphic; bacterial membrane contains sterols, grown on Eaton agar More common in patients \<30, frequent outbreaks in populations in close quarters (military, prision) **Atypical "walking" pneumonia** - HA, non-productive cough, diffuse interstitial infiltrate \***High titer of cold agglutinin (IgM)** -\> agglutinate or lyse RBCs -\> direct Coombs test + **Treatment: macrolides, doxycycline or fluoroquinolone**

Answer 56

Gram(-), lactose fermenting (pink on MacConkey), motile Cause of Noscomial UTIs and pneumonia Multidrug resistance, treat w/ carbapenem

Answer 57

gram (-), slow lactose fermenting (sometimes shows up negative), motile, red pigment when cultured Cause of nosocomial UTIs and pneumonia Treat with carbapenem (multi-drug resistance)

Answer 58

Characteristics: gram (-) bacilli Transmission: resp droplets Virulence factors: **pilli** (filamentous hemagluttinin)-attach to resp. epithelium and then releases toxins (abs against pilus protect against infection); **Pertussis toxin**: ribosylates Gi (disables) -\> increases cAMP and also disables chemokine receptors for lymphocytes -\> inable to enter -\> lymphocytosis; **Adenylate cyclase toxin** -\> directly increases cAMP (same mechanism as edema factor in bascillis anthracis); **Tracheal toxin:** part of peptidoglycan wall of pertussis -\> damages ciliated cells in resp. epithelium Symptoms: 1st presents w/ nonspecific symptoms for 2 weeks conjuctival injucntion, then paroxysmal stage for ~2 months- 'whooping cough' (common in children), convelescent stage- gradual reduction in symptoms for several months Treatment: **macrolides**- start early Vaccine: killed vaccine- no longer used in US; **acellular vaccine** of purified antigens - given to children and is combined with **diptheria and tetnus toxoids (DTaP)**

Answer 59

**obligate intracellular** (cannot produce CoA or NAD+ so must get from host) **coccobacilliary** shape, **weakly gram (-)** **Weil-Felix test;** agglutination rickettsia cross-reactivity with proteus vulgaris (not very sensitive or specific) Symptoms: HA and fever and **vasculitis -\> rash** Treatment: **doxycycline** (tetracyclines)

Bacteria Flashcards

(84 cards)