Bacterial Infections Flashcards
Microbiologic characteristics of corynebacterium diphtheriae
Gram+ rods Non sporeforming Aerobic Non motile Curved Chinese character
3 biotypes of corynebacterium diphtheriae
Mitis
Gravis
Intermedius
Gray- brown adherent pseudomembrane
Diphtheria
Bull neck appearance
Diphtheria
Difference of diphtheria and strep throat
Relative lack of fever
Nonexudative throat
Diagnosis of diphtheria
Culture from nose and throat
Treatment for diphtheria
Pen G 100,000-150,000 units/kg/day q6H x 14 d
Eradicates nasopharyngeal carriage in diphtheria
Erythromycin 40-50 mkD PO or IV x 14 days
Most infectious stage of pertussis
Catarrhal stage
Cough in pertussis
Explosive outbursts in series of 5-10 rapid coughs in 1 expiration and ending in a high pitched whoop (forceful inspiratory gasp)
Medium culture for pertussis
Bordet gengou agar plate
-swab from posterior nasopharynx for 15-30 sec
Presumptive diagnosis for pertussis
Leukemoid reaction (very high wbc ct)
Complications of pertussis
HSOAP
Hemorrhage (subconjunctival or intracranial)
Seizures
Otitis media
Atelectasis, apnea, activation of latent TB
Pneumonia
Treatment for pertussis
Erythromycin 40-50 mkD PO q6 x 14 days
Isolate px for at least 5 days after initiation of erythromycin therapy
Erythromycin x14 days for close contacts
Cause of meningococcemia
Neisseria meningitidis
- gram neg diplococci
- maltose and glucose fermenter
Risk factors for meningococcemia
- with viral infx (esp influenza)
- smoking and smoking exposure
- crowded living conditions (military, dormitories)
- with underlying chronic diseases
- low socioecomomic status
Mode of transmission of meningococcemia
Person to person thru infected droplets
Waterhouse-Friderichsen syndrome
Diffuse adrenal hge
DIC
coma
Death
(In meningococcemia)
Important features of meningococcemia
- abrupt fever, chills, headache, vomiting
- rapid worsening of sx (within hrs)
- mobilliform rash becoming petechial then purpuric within hrs
Difference of meningococcemia from other bacterial meningitis
Less frequent seizures and focal neurologic signs
Poorer prognostic factors of meningococcemia
- Absence of petechiae < 12 hrs before admission
- Absence of meningitis
- Low or normal ESR
DOC for meningococcemia
Penicillin G 250,000-400,000 U/kg/day IV in 4-6 divided doses for at least 5-7 days
Complications of enteric fever
Intestinal hemorrhage (<1%) Perforation (0.5-1%)
Mainstay of diagnosis of enteric fever
Blood culture - positive in 40-60% of px
Treatment for uncomplicated fully sensitive enteric fever
Chloramphenicol
Amoxicillin
Treatment for uncomplicated but multidrug resistance typhoid fever
Fluoroquinolone
Or
Cefixime
Treatment for uncomplicated but quinolone resistant typhoid
Azithromycin
Or
Ceftriaxone
Treatment for chronic carriers of Salmonella typhi
Ampicillin
4 species of shigella
Dysenteriae
Flexneri
Boydii
Sonnei
Shigellosis: pathologic changes occur in what part of GIT
Colon, distal ileum
Watery voluminous diarrhea evolving into frequent small-volume bloody mucoid stools, severe abdominal pain, high fever, abdominal tenderness, rectal tendernes
Shigellosis
Most common cause of bacillary dysentery
Shigella sonnei
Most severe form that causes epidemic dysentery
Shigella dysenteriae type 1
Definitive diagnosis for shigellosis
Culture of stool and rectal swab specimen
Culture medium for shigella
MacConkey agar
XLD
SS agar
Treatment for shigellosis
Oral ampicillin
Microbiologic characteristic of shigella
Gram neg rods
Non lactose fermenter
Non HS
Non motile
Basic virulence trait for shigella
Ability to invade epithelial cells
- Requires VERY LOW INOCULA to cause illness
E.coli : group that causes infantile explosive diarrhea with dhn
ETEC
Traveller’s diarrhea
montezuma’s revenge
ETEC
E.coli : group that causes colonic lesions like dysentery
EIEC
E.coli group that causes nonbloody diarrhea with mucus, prolonged
EPEC
E.coli group that produces shiga-toxin, bloody diarrhea
EHEC
Pathogenesis of E. Coli
Adherence of organisms to a glycoprotein or a glycolipid receptor
*Requires a LARGE INOCULUM of organisms to induce disease
Confirmatory test for cholera
Stool culture
Transport medium of cholera
Cary-blair
Culture medium of choice for cholera
Thiosulfate citrate bile sucrose (TCBS) media
Diarrhea is profuse, watery, painless, rice watery consistency and fishy odor without abdominal cramps or fever
Cholera
“Darting” organisms in darkfield microscopy (rapid test)
Vibrio cholerae
Antibiotics for cholera
Tetracycline
Doxycycline
In cholera, dehydration will lead to what complication
Acute tubular necrosis
In cholera, complication of hypoglycemia?
Coma–> death
In cholera, what is the complication of hypokalemia?
Arrythmia
Muscle affected in trismus
Masseter
Muscle affected in risis sardonicus
Facial and buccal
Progressive difficulty feeding, hunger and crying, paralysis or diminished movt, stiffness to touch, spasms with or without opisthotonus
Neonatal tetanus
Antibiotic of choice for tetanus
Penicillin G
Clean painless ulcers with raised borders that heal spontaneously are called?
Chancre
*Found in PRIMARY syphilis
Syphilis: gummatous lesions
Tertiary syphilis
Syphilis: non pruritic maculopapular rash involving palms and soles
Secondary syphilis
Unilateral or bilateral thickening of steenoclavicular portion of the clavicle–what sign?
Higoumenakis sign
*a late manifestion of congenital syphilis
Barrel-shaped upper central incisors
Hutchinson teeth
*a late manifestion of congenital syphilis
Abnormal first lower molar
Mulberry molars
*a late manifestion of congenital syphilis
Anterior bowing of the midportion of the tibia
Saber shin
*a late manifestion of congenital syphilis
Painless knee joint swelling with sterile synovial fluid in px with congenital syphilis
Clutton joint
*a late manifestion of congenital syphilis
Treatment for CONGENITAL syphilis
Aqueous penicillin G
Treatment for primary, secondary and early latent syphilis
Bemzathine Penicillin G
Jarisch-herxheimer reaction
Acute systemic febrile reaction with exacerbation of lesions occuring in 15-20% of px with acquired or congenital syphilis who are treated with penicillin
Primary lesion in leptospirosis
Damage to the endothelial lining of small blood vessels
Triad of Weil’s syndrome
Jaundice
Uremia
Bleeding
Most useful screening test of leptospirosis
Microscopic slide-agglutination test
Treatment for leptospirosis
Penicillin
Tetracycline
