Microbiology Flashcards
All DNA viruses are double stranded except
Parvovirus (single stranded)
All DNA viruses replicates in the nucleus except
Poxvirus (Cytoplasm)
All DNA viruses are has icosahedral capsid except
Poxvirus (complex)
All DNA viruses has linear genome except
Papillomavirus
Polyomavirus
Hepadnavirus
(circular)
A mnemonic for DNA viruses
PARdon PAPa As HE Has POX DNA
(naked)
PARvovirdea
PAPovavirdea
Adenovirdea
(enveloped)
HErpesvirdea
Hepadnavirdea
POXvirdea
Treatment of Genital Herpes
Doesn’t have any. if you have it, you have it for life.
Symptomatic relief regimen:
Acyclovir 400 mg TID for 5 days (4-3-5)
HSV incubation period
2-7 days
Target or Bull’s eye lesion is specific for
Erythema Multiform (HSV1-2)
Steven Johnson Syndrome
Is Eryhtema Multiform Major (HSV1-2)
-Fever
-Extensive Oral Lesions
-Desquamating lesions
Histological feature of CMV
Owl’s eye
Most commonly available serologic test for measuring antibodies to CMV.
ELISA
Varicella Zoster Virus Incubation Period
1-3 Weeks (7-21 days)
CMV incubation period
3-12 Weeks
Congenital defects associated with CMV
IUGR
Microcephaly
Hepatosplenomegaly
Sensory neural hearing loss
Most common cause of sensory neural hearing loss
CMV
Materno fetal transmission rate of CMV
40%
CMV causes a disease called
Mononucleusis Syndrome
Most common cause of Infectious mononucleosis
Ebstein-Barr Virus
HIV primarily infects which cells?
CD4 cells
Dendritic cells
Macrophage
Perinatal Transmission rates of HIV
with treatment <1%
Without treatment =15%
Perinatal Transmission rates of HIV
with treatment <1%
Without treatment =15%
Risk factors of HIV Perinatal transmission
High maternal viral load
Low CD4 count
Prolonged rupture membrane
Chorioamnionitis
Co morbidity (HCV, malaria)
Breastfeeding
Preterm birth
What disease does rubella cause?
German Measles
Feto- maternal Transmission Rate of Rubella virus
1st trimester = 90%
2nd trimester = 30%
Risk of transmission is decreased after 16 weeks
Obligate Aerobes
Pseudomonas
Mycobacterium
Nocardia
Facultative Anerobes
E. Coli
Staphylcoccus
Enterococcus
Obligate Anerobes
Colistridia
Bacteroids
Prevotella
Which one of the following bacteria produces an exotoxin causing ‘toxic shock syndrome’ associated with tampon usage
Staph aureus
Features of Strept. Pneumonia
- alpha hemolytic strept.
- G+ve diplococci
- Optochin sensitive
- Bile soluble
- Quellung reaction (spelled capsules)
Clinical features of Strept. Pneumonia
MOPS
Meningitis
Otitis media
Pneumonia
Sepsis (in sickle cell disease/ splenic patients)
DOC in treating Strept. Pneumonia
Penicillin
then ceftriaxione and Macrolides
Features of Staph aureus
- G+ve cocci
- Catalase +ve
- Urease -ve
- Coagulase +ve
- Ferments mannitol
Clinical features of Staph aureus
Skin infections
Osteomylitis –> septic arthritis
Endocarditis
Toxic shock syn. (with tampon usage)
Food poisoning
Staph scalded skin syndrome SSSS
Toxin by Staph aureus causes Toxic shock syndrome
TSST-1 Enterotoxin F (superantigen)
Toxin by Staph aureus causes Staph Scalded Skin Syn.
Exfoliate toxin A & B (superantigen)
Most common cause of UTI
E.coli
Most common cause of UTI in sexually active women
Staph. Saprophyticus
Group F streptcocci
Strept. anginosus
Group D streptococci
Enterococci
Strept. Bovis
Most pathogenic beta hemolytic strept
Strept pyogens GAS
GAS is commensal in
Nasopharynx
Features of GAS
Has M protein and Hyaluronic acid capsule
Bactricin Sensitive
Catalase negative
produce different endotoxins & extoxins
Symptoms of GAS
Pyogenic:
- Pharyngitis
-impetigo
-erysipales
-cellulitis
Immungenic:
-Rhemuatic fever
-Glomerulonephritis
Toxogenix:
-toxic shock-like syn.
- Scarlet fever (strawberry tongue
GAS produce three important inflammatory enzymes
- Hyalorunidase-> degrades hyaluronic acid -> Skin infection
- Streptokinase (fibrinolysin)
- DNAse-> degrades DNA in exudates and necrotic tissue
GAS produce important toxins
- Erythrogenic toxin A (pyrogenic toxin A)
- Streptolysin O
- Streptolysin S
- Exotoxin B
Scarlet Fever
- Fever
- Flushed Cheeks
- Endometritis
-Strawberry tongue
Cause of Necrotizing fasciitis type 2
GAS
M Protein virulence factor:
- Fimbrial protein
-Involve in capsule formation - Anti phagocytic
-Involve in destroying c3 convertas and prevents opsonization by c3b - Responsible for organ adhesion and invasion
What type of hypersensitivity is Rheumatic fever
Type II
What type of hypersensitivity is Glomerulonephritis
Type III
Which is the single most appropriate treatment of Chlamydia vaginal infection in pregnancy
Erythromycin 500 mg BID/14 days
Early onset neonatal infection of GBS
before 7 weeks - presented by neonatal sepsis
Late onset neonatal infection of GBS
7 weeks to 3 months - presented by meningitis (capsular serotype III) most common
GBS clinical features in neonates
Neonatal Sepsis
Meningitis
Pneumonia
GBS clinical features in adults
Endocarditis
Arthritis
Pneumonia
Osteomyelitis
Postpartum endometritis
Main predisposing factor of GBS transfer to neonates
Prolonged Rupture of membranes in women who are colonized with the organism
Main predisposing factor of GBS in Adults
Diabetes Mellitus
risk factors for neonatal GBS
- Preterm Delivery (<37 w)
- Prolonged ROM (>18 before time of delivery)
- Prolonged Labour
-Choriamnionitis
Antibiotic Regimen to treat GBS
- Benzylpenicilin G 3 gm IV then 1.5 gm IV/4 hrs until delivery
- Clindamycin 800 mg IV/ 4hrs until delivery
- Erythromycin 500 mg IV/ 6hrs until delivery
Most Enterococci species to cause infection
E. faecalis 85-90%