Etiology
• Brucella: Abortus(Cattle),Melitensis (Sheep,Goat)Suis(Swin),Canis(Dog)
• G- Coccobacil• Aerobic, Non-spore
forming• Non motile• Blood or Choclate agar
Pathogenesis
• Inoculation in skin ,Eye
(Through abrasion or conjunctiva)
• Inhalation
(Infected aerosol)• Ingestion
(Meat, Dairy products)
Risk of infection depends
1. Nutritional status
2. Immune status
3. Rout of inoculum
4. Species of brucella
Pathogenesis
• Survive& Replicate within phagocytes&Monocytes• Infected macrophages localized within reticuloendothelial
system(Granuloma formation in spleen,liver,bone marrow)
Clinical manifestationTriad: Fever, Arthralgia/Arthritis,Hepatosplenomegaly
• + History of animal or food exposure
• Acute or insidious symptoms(2-4 wk after inoculation)
• Refusal to eat• Refusal to bear weight• Lassitude• FTT• Headache• Inattention/Depression
• Abdominal pain• Headache• Diarrhea• Rash• Night sweets• Weakness• Fatigue• Cough• Vomiting• Pharyngitis
Diagnosis
• WBC Normal or low
• + History of animal or food exposure
• Recovering organisms (blood’ bone marrow’..)
• Serum agglutination test: >1/160(Antibody against Abortus ,Melitensis, Suis, but not Canis)• 2ME
• False positive SAT
Yersinia entrocolitica
Vibrio cholerae
Francislla tularensis
• False negative SAT
Prozen effect
Treatment
> or = 9 years old• 1-Doxycycline 200 mg/D PO 6 WK
+
Streptomycin 1 g/D IM 1-2 WK
OR
Gentamycin 3-5 mg/kg/d IM/IV 1-2 WK
--------------------------------------------------• 2-
Doxycycline 200 mg/D PO 6 WK
+
Rifampin 600-900 mg/D PO 6 WK
< 9 years old
TMP-SMZ: po 45 days
(TMP 10 mg/Kg/D)
(SMZ 50 mg/KG/D)
+
Rifampin 15-20 mg/kg/D PO 45 days
Meningitis,Osteomyelitis,Endocarditis:
Doxy + Genta +/- Rifampin
Etiology
Salmonellae(G- ‘Facultative’Bacilli)
• Antigens: Flagellum(H)’ Cell wall(O)’ Envelope(Vi)• Serogroups on the basis of O antigen: A’ B’ C1’ C2’ D’ E• Serotypes: S.Typhi’ S.Paratyphi’….• Transmission: Water’ Food(beef’poultry’milk’egg’..)
Salmonella Gastroentritis (Nontyphoidal)
Epidemiology
• Age: <4 y/o (< 1y/o)
• Source of infection: Poultry’eggs’
egg product ’meats’ pet reptile
• Transmission: Carrier (Human)• Incubation period: 6-72 hr. (usually less than 24 hr.)
• Peak incidence: Late summer &Early fall
Pathogenesis
• Ingestion
• Attached to “M” cells
• Phagocytosed by macrophages
• Replication
• Bacteremia
Clinical manifestations
• Self limited diseases: 3-7 days
• Onset: Abrupt
• Nausea’ Vomiting’ Crampy abdominal pain
• Loose watery stool
• Malaise’ headache’ chills
• Fever 38-38.9 c (70%) for 48 hour
At risk of complications
• Impaired immune function(T-Cell)• HIV infection• Organ transplantation• Lymphoproliferative diseases• Hemoglobinopathies
(Sickle cell disease’..)• CGD• Malaria• Very old or very young
Complications
• Dehydration’Shock• Localized infection: Pneumonia Empyema Abscesses Osteomyelitis Septic arthritis Postinfectious arthritis Pyelonephritis meningitis
Treatment
• Correction of shock’ dehydration’…
• Antibiotics:
1-Infants < 3 mo.
2-Child with immunodeficiency’ Malnutrition
Malignancy’ Intravascular catheter or
other foreign material
Treatment
• Ceftriaxone or Cefotaxime Septicemia’ Enteric fever’ Metastatic site of infection
• Amoxicillin• Co-trimaxozole• Fluroqinolones• Chloramphenicol
Typhoid fever
• In US:400 Cases per year &Usually under 20 y/o
• Worldwide:16 million cases per year and 600’000 death
• Infected only human
Pathogenesis
• Invasions on upper small intestine
• Monocyte phagocyte
• Monocyte carry organism from blood to other RES
• Organism proliferation
• Lymph node’ liver & spleen inflammation
• Secondary septicemia
Clinical manifestation
• Infant:
mild GE to severe septicemia without diarrhea
Fever’ hepatomegaly ’ jaundice’ anorexia’ lethargy’ weight loss
Clinical manifestation
• Child: High fever’ malaise ’lethargy’ myalgia’ headache’ rash’
Hepatomegaly’ abdominal pain and tenderness’ diarrhea(50%)’ constipation
obtunded ’delirium’ confusion ’splenomegaly’ Macular (Rose spot) or Maculopapolar rash(30%) High T with low PR (Typically each 1 degree above 38.3° C Rise PR 10/min)
Complications
• Intestinal perforation(0.5-3%)• Severe GI hemorrhage(1-10%)• Toxic encephalopathy• Cerebral thrombosis• Acute cerebral ataxia• Aphasia• Optic neuritis• Deafness• Transverse myelitis
• Acute cholecystitis• Pneumonia• Pyelonephritic• Endocarditis• Meningitis• Osteomyelitis• Septic arthritis
Diagnosis & Differential diagnosis
• Diagnosis
Cultures:
Blood’ Urine’ Stool’ Bone marrow’ Lymph nodes’ Deudenal fluied’
Reticuloendothelial tissue’
• Differential diagnosis
Bronchitis
Bronchopneumonia
Gastroenteritis
Influenza
Treatment
Drugs:• Ceftriaxone• Ampicillin• Chloramphenicol• Co-Trimoxozole• Ciprofloxacin• Azithromycin
Surgery• Cholecystectomy
Prognosis
• With treatment : Mortality <1%
• Without treatment : Relapse up to 10%
• Chronic carrier: Excrete S.typhi for more than 3 mo.