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USMLE STEP 1 > Micro Systems > Flashcards

Micro Systems Flashcards

1
Q

Normal Dominant Flora of Skin

A

Staphylococcus epidermidis

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2
Q

Normal Dominant Flora of Nose

A

Staph epidermidis. Colonies by Staph aureus

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3
Q

Normal Dominant Flora of Oropharynx

A

Viridans Group Strep

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4
Q

Normal Dominant Flora of Dental plaques

A

Streptococcus mutans

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5
Q

Normal Dominant Flora of Colon

A 
Bacteroides fragilis (more)
E. coli (less)
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6
Q

Normal Dominant Flora of Vagina

A

Lactobacillus

Colonies by E coli and GBS

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7
Q

Neonates delivered by Cesarean section re flora?

A

They have no flora but are rapidly colonized after birth

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8
Q

Staph aureus and B cereus food poisoning course

A

Starts quickly and ends quickly

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9
Q

Contaminated seafood

A

Vibrio parahaemolyticus and V vulnificus (can cause wound infection from contact with contaminated water or shellfish)

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10
Q

Reheated rice

A

“be serious”

B cereus

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11
Q

Meats, Mayonnaise, Custard

A

S aureus

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12
Q

Reheated meat dishes leading to watery diarrhea

A

Clostridium perfringens

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13
Q

Improperly canned foods (bulging cans)

A

Clostridium botulinum

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14
Q

Undercooked meat

A

E coli O157:H7

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15
Q

Poultry, meat, eggs

A

Salmonella

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16
Q

Bugs that can mimic appendicitis

A

Yersinia enterocolitica causes mesenteric adenitis
Nontyphoidal Salmonella
Campylobacter jejuni

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17
Q

Causes of Bloody Diarrhea with signs

A

Campylobacter: Comma or S shaped, grows at 42
Salmonella: Lac-, Flagella
Shigella: Lac-, low ID50
EHEC, EIEC
Yersinia enterocolitica: Daycare outbreaks, pseudoappendicitis
Entamoeba histolytica

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18
Q

Causes of Watery Diarrhea

A

Enterotoxigenic E coli: Traveler’s, ST and LT toxin
V Cholerae: comma-shaped, rice-water
C difficile: bloody w/ pseudomembranous colitis
C perfringens: also gas gangrene
Protazoa: Giardia, Cryptosporidium (in immunocompromised)
Rotavirus, Norovirus

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19
Q

Pneumonia in neonate (less than 4 weeks)

A

GBS, E coli

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20
Q

Pneumonia in children (4 weeks to 18 years)

A

“Runts May Cough Chunky Sputum”

RSV, Mycoplasma, C. pneumoniae (school age), Chlamydia trachomatis (infant to 3 years), Streptococcus pneumoniae

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21
Q

Pneumonia in adults (18 years to 40 years)

A

Mycoplasma, C pneumoniae, S pneumoniae

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22
Q

Pneumonia in adults (40 years to 65 years)

A

S pneumoniae, H influenzae, Anaerobes, Viruses, Mycoplasma

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23
Q

Pneumonia in elderly

A

S pneumoniae, Influenza, Anaerobes, H influenzae, H influenzae, Gram- rods

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24
Q

Special Nosocomial Infections

A

Staph, Enteric Gram negative Rods

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25
Special Immunocompromised infections
Staphylococcus, Enteric Gram- rods, Fungi, Viruses, Pneumocystis jirovecii - w/ HIV
26
Special infections with aspiration
Anaerobes
27
Special infections w/ EtOH and IV drug users
S pneumoniae, Klebsiella, Staph
28
Special infections in CF
Pseudomonas, S aureus, S pneumoniae
29
Special infections in Post-Viral pt
Staph, H influenzae, S pneumoniae
30
Bugs that cause atypical pneumonia
Mycoplasma, Legionella, Chlamydia
31
Meningitis in a newborn (0 to 6 months)
GBS, E coli, Listeria
32
Meningitis in a child (6 months to 6 years) PathoPhys Presentation
``` Streptococcus pneumoniae Neisseria meningitidis Enteroviruses Haemophilus influenzae type B Polio Last 2 in non immunized children Microbe colonizes nasopharynx leading to myalgias and paralysis ```
33
Meningitis in a adults (6 years to 60 years)
S pneumoniae N meningitidis (#1 in teens) Enteroviruses HSV
34
Meningitis in elderly (60+)
S pneumoniae Gram- rods Listeria
35
Meningitis Treatment
Ceftiazone and Vancomycin empirically | Add ampicillin if Listeria is suspected
36
Viral causes of meningitis
Enterovirus (esp coxsackievirus), HSV2 (HSV1 = encephalitis), HIV, West Nile Virus, VZV
37
Meningitis in HIV pt
Cryptococcus, CMV, toxoplasmosis (brain abscess), JC virus (PML)
38
Recent changes in H influenzae meningitis
Decreased with introduction of conjugate H influenzae vaccine in last 10-15 years. Todays cases are in un-immunized children
39
``` CSF findings in Bacterial meningitis Opening pressure Cell type Protein Sugar ```
Opening pressure ↑ PMNs Protein ↑ Sugar ↓
40
``` CSF findings in Viral meningitis Opening pressure Cell type Protein Sugar ```
Opening pressure Normal or ↑ Lymphocytes Protein is Normal or ↑ Sugar is Normal
41
``` CSF findings in Fungal/TB meningitis Opening pressure Cell type Protein Sugar ```
Opening pressure ↑ Lymphocytes Protein is Normal or ↑ Sugar ↓
42
Osteomyelitis w/ nothing else
S aureus
43
Osteomyelitis in sexually active individual
Neisseria gonorrhoeae (rare), septic arthritis more common
44
Osteomyelitis in diabetic or IV drug user
Pseudomonas aeruginosa, Serratia
45
Osteomyelitis in Sickle cell disease
Salmonella
46
Osteomyelitis in Prosthetic replacement
S aureus and S epidermidis
47
Osteomyelitis in Vertebral disease
Mycobacterium Tuberculosis (Pott's disease)
48
Osteomyelitis in cat and dog bite/scratches
Pasteurella multocida
49
Osteomyelitis Mostly in... Signs
Children | Elevated CRP and ESR
50
``` UTIs Presentation Labs PathoPhys Causes in males Causes in elderly Can progress to... ```
Dysuria, Frequency, Urgency, Suprapubic pain WBCs (but not casts) in urine Males: infants w/ congenital defects, vesicoureteral reflux Elderly: Enlarged prostate Pyelonephritis
51
Pyelonephritis presentation
Fever, Chills, Flank pain, CVA tenderness, Hematuria, WBC casts
52
UTIs in women Frequency Predisposing factors
10x more likely in women because of shorter urethra colonized by fecal flora Obstruction, Kidney surgery, Catheterization, GU malformation, Diabetes, Pregnancy
53
UTI Dx markers
+Leukocyte esterase test = bacterial UTI +Nitrite test = Gram- bacterial UTI +Urease test = Proteus, Klebsiella -Urease test = E coli or Enterococcus
54
UTI bugs
E coli: #1. Green metallic sheen on EMB Staph saprophyticus: #2 Klebsiella: #3. Large mucoid capsule + viscous colonies Serratia: Red pigment. Nosocomial and drug resistant Enterobacter cloacae: Nosocomial and drug resistant Proteus mirabilis: Swarming on agar, Urease+, Struvite stones Pseudomonas aeruginosa: Blue-green pigment, fruity odor. Nosocomial and drug resistant
55
ToRCHeS Infection What are they? Presentation
Mother --> fetus. Transplacental in most cases or via delivery (HSV2) HSM, Jaundice, Thrombocytopenia, Growth retardation
56
Names of ToRCHeS Infection
``` Toxoplasma gondii Rubella CMV HIV HSV2 Syphilis ```
57
Toxoplasma gondii Mode of transmission Maternal manifestation Neonatal manifestation
Cat feces or ingestion of undercooked meat Usually asymptomatic; Lymphadenopathy (rarely) Classic Triad: Chorioretinitis, Hdyrocephalus, and Intracranial calcification
58
Rubella Mode of transmission Maternal manifestation Neonatal manifestation
Respiratory droplets Rash, Lymphadenopathy, Arthritis Classic triad: PDA (or pulmonary artery hypoplasia), Cataracts, and Deafness Blueberry muffin rash
59
CMV Mode of transmission Maternal manifestation Neonatal manifestation
Sexual contact, organ transplant Usually asymptomatic. Mononucleosis-like illness Hearing loss, Seizures, Petechial rash, Blueberry muffin rash
60
HIV Mode of transmission Maternal manifestation Neonatal manifestation
Sexual contact, Needlestick Variable presentation depending on CD4 count Recurrent infections, Chronic diarrhea
61
HSV2 Mode of transmission Maternal manifestation Neonatal manifestation
Skin or mucous membrane contact Usually asymptomatic. Herpetic (vesicular lesions) Encephalitis, Herpetic (vesicular) lesions
62
Syphilis Mode of transmission Maternal manifestation Neonatal manifestation
Sexual contact Chancre (primary) and disseminated rash (secondary) are the 2 stages likely to result in fetal infection Stillbirth, Hydrops Fetalis If child survives presents with facial abnormalities [notched teeth (Hutchinson's teeth), saddle nose, short maxilla, Dry wrinkled skin, yellow-brown hue, hemorrhagic rhinitis], saber sings, CN VIII deafness
63
Childhood rash that begins at head and moves down --> fine truncal rash
Rubella virus | Usually associated with lymphadenopathy
64
Childhood rash beginning at head and moving down preceded by cough, coryza, conjunctivitis, and blue-white spots on buccal mucus
Measles
65
Childhood vesicular rash beginning on trunk and spreading to face and extremities with lesions of different ages
Chickenpox (VZV)
66
Childhood (infant) macular rash over body appears after several days of high fever, febrile seizures
Roseola (HHV6)
67
Childhood "slapped cheek" rash on face
``` Erythema infectionsum (parvovirus B19) Can cause hydrops fetalis in pregnant women) ```
68
Childhood erythematous sandpaper rash with fever and sore throat
Scarlet fever from Strep pyogenes
69
Childhood vesicular rash on palms and soles with ulcers in oral mucosa
Hand-Foot-Mouth Disease (Coxsackievirus A)
70
Urethritis, Cervicitis, PID, Prostatitis, Epididymitis, arthritis, Creamy purulent discharge
Neisseria gonorrhoeae
71
Painless Chancre
Primary syphilis (Treponema pallidum)
72
Fever, lymphadenopathy, Skin rashes, Condylomata lata
Secondary syphilis (Treponema pallidum)
73
Gummas, Tabes Dorsalis, General Paresis, Aortitis, Argyll Robertson pupil
Tertiary syphilis (Treponema pallidum)
74
Painful genital ulcer with inguinal adenopathy
Chancroid caused by Haemophilus ducreyi | "It's so painful, you DO CRY"
75
Painful penile, vulvar, or cervical vesicles and ulcers | Fever, Headache, Myalgia
Genital herpes | HSV2. Less commonly HSV1
76
Urethritis, Cervicitis, Conjunctivitis, Reiter's Syndrome, PID
Chlamydia from Chlamydia trachomatis (D-K)
77
Infection of lymphatics, Genital ulcers, Lymphadenopathy, Rectal strictures
Lymphogranuloma venereum from Chlamydia trachomatis (L1-L3)
78
Vaginitis, Strawberry colored mucosa, motile in wet prep
Trichomonas vaginalis
79
Opportunistic infections Kaposi sarcoma, Lymphoma
AIDS from HIV
80
Genital warts, Koilocytes
HPV 6 and 11
81
Jaundice
HBV
82
Non-Inflammatory, Malodorous Discharge (fishy smell), Positive whiff test, Clue cells
Gardnerella vaginalis
83
PID Causes Presentation May include...
``` Chlamydia trachomatis (subacute, often undiagnosed), Neisseria gonorrhoeae (acute) Cervical motion tenderness (chandelier sign), Purulent cervical discharge Salpingitis, Endometriosis, Hydrosalpinx, Tubo-Ovarian Abscess ```
84
PID can lead to...
Hugh-Curtis Syndrome | Infection of the liver capsule and violin string adhesion of parietal peritoneium to liver
85
Salpingitis is a risk factor for...
Ectopic pregnancy, Infertility, Chronic pelvic pain, Adhesions
86
Nosocomial infections in a newborn nursery
CMV, RSV
87
Nosocomial infections in urinary catheterizations
E coli, Proteus, Mirabilis
88
Nosocomial infections in Respiratory Therapy Equipment
Pseudomonas aeruginosa | "Presume Pseudomas when Air or Water are involved"
89
Nosocomial infections for work in renal dialysis unit
HBV
90
Nosocomial infections in hyperalimentation
Candida albicans
91
Nosocomial infections in water aerosols
Legionella
92
Painful throat. Grayish oropharyngeal exudate in painful throat in an un-immunized child
Corynebacterium diphtheriae elaborating toxin that causes necrosis pharynx, cardiac and CNS tissue
93
Fever, dyspnea, Drooling, difficulty breathing due to cherry red edematous epiglottis in un-immunized child
H influenzae type B | Can cause epiglottitis in fully immunized children too
94
Pus, Empyema, Abscess
S aureus
95
Pediatric infection
Haemophilus influenzae (including epiglottitis)
96
Pneumonia in CF or burn pt
Pseudomonas aeruginosa
97
Branching rods in oral infection w/ sulfur granules
Actinomyces israelii
98
Traumatic open wound
Clostridium perfringens
99
Surgical wound
S aures
100
Dog or cat bite
Paseurella multocida
101
Currant jelly sputum
Klebsiella
102
+PAS stain
Tropheryma whippelei
103
Sepsis/Meningitis in a newborn
GBS
104
Healthcare provider
HBV from needlestick
105
Fungal infection in diabetic or immunocompromised pt
Mucor or Rhizopus
106
Asplenic pt
Encapsulated microbes "SHiN" S pneumoniae, H influenzae type B, N Meningitidis
107
Chronic Granulomatous disease
Catalase+ microbes esp S aureus
108
Neutropenic pt
Candida albicans (systemic), Aspergillus
109
Facial nerve palsy
Borrelia burgdorferi (Lyme disease)
110
Infectious cause of pericarditis
Coxsackie B
111
Best Way to Prevent Tetanus?
Vaccinate Mother
112
Most common causes of UTIs?
E coli | Staph saprophyticus
113
Sepsis with black rash
Pseudomonas

USMLE STEP 1 (25 decks)

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