bacinfxns Flashcards
incubation period of diphtheria (via resp droplets)
2-6 days
3 biotypes of diphtheria
mitis; gravis; intermedius
offending agent in pseudomembranous pharyngitis
Corynebacterium diptheriae
bullneck appearance and leather-like adherent membrane and extension beyond the faucial area
diptheria
difference bet diphtheria and strep throat
diphtheria: relative lack of fever and nonexudative throat
Dx of diphtheria
culture from nose and throat(negative results does not rule it out)
rationale for giving antimicrobials in diphtheria
to halt toxin production; treat localized infection and prevent transmission to contacts
Tx for diphtheria
Pen G IM/IV 100k-150k U/kg/day q6 fo 14 days; Erythromycin 40-50/mkd orally or IV for 14 days eradicates nasopharyngeal carriage
how to determine treatment of diphtheria
2 successive negative cultures taken 24 hrs apart after completion of therapy; antimicrobial prophylaxis given for 7-10days and diphtheria toxoid for asymptomatic carriers
most infectious stage of whooping cough
catarrhal stage
incubation period of whooping cough
7-10 days
characteristic of cough in pertussis
explosive outburst in series of 5-10 rapid coughs in one expiration and ending in a high pitched whoop(forceful inspiratory gasp) often associated with suffusion of face and popping out of eyes and vomiting
presumptive diagnosis of pertussis
symptoms + very high WBC count(leukemoid rxn) with absolute lymphocytosis
Dx of pertussis
(+) growth of culture in Bordet-Gengou agar from a swab taken from the posterior nasopharynx for 15-30s
complications of pertussis
Hemorrhage; Seizures; Otitis media;Atelectasis;apnea;activation of latent TB;Pneumonia
Tx of pertussis
Erythromycin 40-50mkd PO q6 x 14days; Erythromycin for 14 days given promptly to all household contacts and other close contacts
Diffuse adrenal hemorrhage; DIC; coma; death
Waterhouse-Friedrichsen syndrome
important features of meningococcemia
abrupt onset of fever chills headache vomiting; rapid worsening of symptoms within hours; initially morbiliform rash becoming petechiae then purpuric within hours
DOC for meningococcemia
Pen G 250k-450k U/kg/day IV in 4-6 divided doses at least 5-7days
who are considered exposed in meningococcemia
household; school or day care contacts during the 7 days before exposure
Prophylactic tx for those exposed to meningococcemia
Rifampicin 10mkd q12 x4doses; or Ceftriaxone 125mg single dose IM for less than 12yo; >18yo:Ciprofloxacin 500mg PO single dose
most common mode of transmission of enteric fever
ingestion of food or water contaminated with S. typhi from human feces
when is enteric fever infectious
throughout the duration of fecal excretion
incubation period of enteric fever
7-14days
what dse entity do you find rose spots
enteric fever
rare complications of enteric fever
toxic myocarditis; delirium; increased ICP; pyelonephritis; meningitis; endocarditis
when does the stool and urine cultures become positive in enteric fever
after the 1st week of illness
mainstay of diagnosis in enteric fever
blood culture
Tx for uncomplicated and fully sensitive enteric fever
Chlorampenicol 50-75mkd x14-21days OR Amoxicillin 75-100mkd for 14days
Tx for severe typhoid fever
Fully sensitive: Ampicillin at 100mkd x14days; MDR: Fluoroquinolone 15mkd x10-14days; Quinolone resistant: Ceftriaxone 60-75 mkd x10-14days
who are considered chronic carriers of S. typhi
those who secrete S. typhi for more than 3mos
at what age is Shigellosis most common
2-3years old
basic virulence trait of shigella
ability to invade intestinal epithelial cell (it crosses the colonic epithelium through the M cells overlying the Peyer patches)
What species of Shigella produce Shiga toxin; a potent protein-synthesis inhibiting exotoxin that causes HUS
Shigella dysenteriae
Presumptive diagnosis of shigellosis
fecal leukocyte and blood; leukocytosis
definitive diagnosis of shigellosis
culture of stool and rectal swab (MacConkey agar; xylose-lysine deoxycholate; SS agar)
Empirical tx of shigellosis
Cefixime 8mkd PO q12 x5days; OR Ceftriaxone 50mkd IV or IM OD x5days; OR Azithromycin 12mkd PO 1st day then followed by 6mkd for the next 4days; AND Zinc 20mg/day x14days improves immune response to Shigella
group of E. coli that causes infantile explosive diarrhea with dehydration; few or no structural changes in the mucuso
ETEC
group of E.coli that causes colonic lesions like dysentery
EIEC
group of E.coli that causes nonbloody diarrhea with mucus
EPEC
group of E.coli that causes significant dehydration
EAEC
group of E.coli that produces shiga-toxin
EHEC
Tx for culture confirmed ETEC
TMP-SMX
slightly curved; gm(-) aerobic bacillus that has serotypes 01 and 0139
Vibrio cholerae
predominant strain of cholera
O1 El Tor
laboratory finding in cholera
hemoconcentration; hypokalemia; hyponatremia ; hypchloremia; metabolic acidosis
confirmatory test for cholera
Cary-Blair transport medium plated onto TCBS (thousulfate-citrate-bile-sucrose media)
rapid test for cholera
darkfiel microscopy (wetmount of liquid stool examined for DARTING organism)
complications of cholera
dehydration that may lead to acute tubular necrosis; hypoglycemia; hypokalemia; pulmonary edema
DOC for cholera
for 9yo:Tetracycline:50mkd PO qid x3days
neurotoxin produced by C. tetani
tetanospasmin
alternative to Ig Tet
Human IVIG
tx for tetanus for best survival rates
NM blockers (Vecuronium and Pancuronium)
clean painless papule (chancre) that appears 2-6wks after inoculation and heals spontaneously within 4-6hr
primary syphilis
nonpruritic maculopapular rash on the palms and soles (may be pustular) manifests when if primary syphilis is not treated
2-10 wks (secondary syphilis)
neurologic; cardiovascular GUMMAtous lesion (granulomas of the skin and MSS)
tertiary syphilis (latent)
refusal to move the involved extremity in early congenital syphilis
pseudoparalysis of Parrot
barrel-shaped upper central incisors in late congenital syphilis
Hutchinson teeth
painless knee joint swelling with sterile synovial fluid in late congenital syphilis
Clutton joint
linear scars on mouth anus and genitals in late congenital syphilis
rhagades
Dx of congenital syphilis
darkfield microscopy; immunofluorescence; nontreponemal tests (VDRL RPR); Treponemal test(TPI FTA-ABS MHA-TP)
Diagnostic test for syphilis to determine disease activity
nontreponemal tests (VDRL and RPR)
Diagnostic test fro syphilis that measure antibody specific for T. pallidum
treponemal tests (TPI FTA-ABS MHA-TP)
Tx for congenital syphilis
Aqeous Pen G 100k-150k Ukd IV for 10-14 days
Tx for primary secondary and early latent syphilis
Benzathine Pen G 50k U/kg IM single dose
acute systemic febrile rxn with exacerbation lesions occurs in 15-20% of all px with acquired or congenital syphilis who are treated with penicillin
Jarisch-Herxheimer rxm
technique to visualize Leptospira
darkfield microscopy or silver staining impregnation staining
manifestions of anicteric leptospirosis
conjunctival suffusion with photophobia and orbital pain; truncal maculopapular rash; fever; chills; headache; malaise; nausea; vomiting; severe muscle pain and tenderness on the LE
other term for Icteric Leptospirosis
Weil’s syndrome
Weil’s syndrome
hemorrhage and cardiovascular collapse; RUQ pain; hepatomegaly; increased liver enzymes; hyperbilirubinemia; azotemia-oliguria-anuria
most useful screening test for Leptospirosis
microscopic slide-agglutination test using killed antigens
Tx of Leptospirosis
Parenteral Pen G 6-8 M U/m2/day in 6 divided doses for 1wk; OR Tetracycline
