10191 - Laboratory Criteria for Identification of B...

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Unformatted text preview: Laboratory Criteria for Identification of B. anthracis s s From clinical samples, such as blood, cerebrospinal fluid (CSF), skin lesion (eschar), or oropharyngeal ulcer Encapsulated gram-positive rods on Gram stain From growth on sheep blood agar: Large gram-positive rods Nonmotile Nonhemolytic Chotani, 2003 Laboratory Criteria for Identification of B. anthracis s s Rapid screening assay (PCR- and antigen-detection based) for use on cultures and directly on clinical specimens Confirmatory criteria for identification of B. anthracis Capsule production Lysis by gamma-phage Direct fluorescent antibody assay (DFA) Chotani, 2003 Gram Stain Morphology of B. anthracis Broad, gram-positive rod: 11.5 x 35 s Oval, central to subterminal spores: 1 x 1.5 with no significant swelling of cell s Spores usually NOT present in clinical specimens unless exposed to atmospheric O2 s Chotani, 2003 B. anthracis Gram-positive, spore-forming, non-motile bacillus Chotani, 2003 Gram Stain of Blood in Culture Media Gram-positive bacilli in long chains (original magnification 20). Enlargement shows typical "jointed bamboo-rod" appearance of Bacillus anthracis (original magnification 100). Reprinted from Borio et al.36 Chotani, 2003 B. anthracis: Presumptive Identification Clinical specimen (blood, CSF, etc.) Gram stain Isolate on SBA Capsule production Colony morphology Hemolysis Motility Gram stain Spores Malachite green Chotani, 2003 B. anthracis: Confirmatory Identification Isolate Phage lysis Capsule Horse blood Bicarbonate media DFA Capsule antigen Cell wall (M'Fadyean Stain) (M'Fadyean stain India ink stain) Chotani, 2003 Immune Protection Against Anthrax s Live cellular vaccines "Sterne" type live spore (toxigenic, noncapsulating) Former USSR STI live spore (toxigenic, noncapsulating) "Pasteur" type (mixed culture, reduced virulence) US "anthrax vaccine adsorbed" (AVA)--not licensed for use in civilian populations UK "anthrax vaccine precipitated" (AVP) AI3+; Freund's; Saponin, Monophosphoryl lipid A; Ribi s Sterile, acellular vaccines s Recombinant PA research vaccines Chotani, 2003 Anthrax in the US - 2001 s s s s In October 2001, the first inhalational anthrax case in the United States since 1976 was identified in a media company worker in Florida. A national investigation was initiated to identify additional cases and determine possible exposures to Bacillus anthracis. Surveillance was enhanced through health-care facilities, laboratories, and other means to identify cases, which were defined as clinically compatible illness with laboratory-confirmed B. anthracis infection. From October 4 to November 20, 2001, 22 cases of anthrax (11 inhalational, 11 cutaneous) were identified; 5 of the inhalational cases were fatal. Chotani, 2003 Epidemic curve for 22 cases of bioterrorismrelated anthrax, United States, 2001. Anthrax Meningitis Hemorrhagic meningitis is a potential complication of anthrax, and may accompany cutaneous, gastrointestinal, or inhalational anthrax (seen in 50% of inhalational cases) Death almost universal within 1-6 days after onset of illness Rare survivors have been treated using appropriate antibiotics in combination with antitoxin, prednisone or both Chotani, 2003 Recommended Postexposure Prophylaxis to Prevent Inhalational Anthrax Initial Therapy Duration Adults Ciprofloxacin 60 days (including pregnant 500 mg PO BID women and OR immunocompromised) Doxycycline 100 mg PO BID Children Ciprofloxacin* 60 days 1015 mg/kg PO Q 12 hrs Change to OR amoxicillin Doxycycline: if susceptible >8 yrs and >45 kg: 100 mg PO BID >8 yrs and <45 kg: 2.2 mg/kg PO BID <8 yrs: 2.2 mg/kg PO BID Chotani, 2003 Cutaneous Anthrax Treatment Protocol* for Cases Associated with Bioterrorist Event Category Adults Initial Therapy (Oral) Ciprofloxacin (Including pregnant women 500 mg BID and immunocompromised) OR Doxycycline 100 mg BID Children Duration 60 days Ciprofloxacin** 60 days (including immuno1015 mg/kg Q 12 hrs compromised) OR Doxycycline: >8 yrs and >45 kg: 100 mg BID >8 yrs and <45 kg: 2.2 mg/kg BID <8 yrs: 2.2 mg/kg BID Chotani, 2003 Inhalational Anthrax Treatment Protocol* for Cases Associated with Bioterrorist Events Category Adults Initial therapy (intravenous) Duration Ciprofloxacin (Including pregnant 400 mg Q 12 hrs women** and OR immunocompromised) Doxycycline 100 mg Q 12 hrs AND Switch to oral therapy when clinically appropriate: Ciprofloxacin 500 mg BID OR One or two additional antimicrobials Doxycycline 100 mg BID Continue for 60 days (IV and PO combined) Chotani, 2003 Smallpox Chotani, 2003 Smallpox Worst-case scenario biological agent Highly contagious once rash present (not before) World's population is largely susceptible Up to 30% case fatality rate in non-immune Secondary attack rate of 25-40% (10-20 secondary cases can be expected per index case) No specific treatment available Globally very few physicians currently practicing have seen actual cases Virus has been weaponized by Soviets, uncertain who exactly owns viable stocks Chotani, 2003 Smallpox Caused by Variola virus (Orthopox virus) Immunization of U.S. civilian population suspended in 1980, U.S. military recruits in 1989 Virus is stable in environment Spread primarily by respiratory droplets, also by contact, fomites Two distinct types of smallpox: Variola Minor (Alastrim): diminutive lesions and mild systemic toxicity Variola Major: Ordinary (subtypes discrete, semiconfluent, confluent), Modified, Flat, Hemorrhagic Chotani, 2003 Smallpox Clinical Presentation 7-17 day incubation period Prodromal phase: 2-4 days of malaise, fever, rigors, headache, backache, delirium Rash then develops on face, hands, forearms and legs, including palms and soles (centrifugal distribution is important distinguishing feature). Initial rash is maculopapular. In 1-2 days, lesions become vesicular, then evolve into round, tense pustules deeply imbedded in the dermis. Crusts form on 8th to 9th day of rash Crusts separate to form depressed, hypopigmented scars Chotani, 2003 Smallpox Chotani, 2003 Chotani, 2003 Chotani, 2003 Smallpox Outbreak, Meschede Hospital, Germany, 1970 Wehrle PF, Bull WHO 1970;43:669 Chotani, 2003 Meschede Hospital Outbreak Chotani, 2003 Diagnosis of Smallpox Recognition of clinical features in early index cases is key Identification of a single case of smallpox constitutes an international medical emergency, and should be considered evidence of a bioterrorist attack Confirmation of diagnosis is made by demonstration of characteristic virions on electron microscopy of vesicular scrapings Chotani, 2003 Management of Smallpox Immediate quarantine of affected and exposed individuals for 17 days Only supportive care is available. Cidofovir has demonstrated in vitro activity Immediate vaccination of all exposed persons with Vaccinia virus vaccine by inoculation with a bifurcated needle (scarification) Administration of Vaccinia Immune Globulin (VIG), 0.6 ml/kg intramuscularly, concomitant with vaccination Active and passive immunization is effective at preventing disease and death if given within 7 days of exposure Chotani, 2003 For the past half-century the main concern was a nuclear Armageddon caused by atomic weapons. However, with the discovery of various offensive biological warfare programs around the globe, the concern regarding intentional use of viruses and microorganisms as weapons of mass destruction increased during the past decade. The threat of biological warfare is real. It is now widely acknowledged that the biological weapons, in terms of destructiveness and in the generation of panic and civil disorder could produce an effect that is equivalent to that of a nuclear weapon. Chotani, 2003 Medical professionals globally should make sure that the world does not suffer a catastrophe as a result of the use of biowarfare pathogens Chotani, 2003 War on Diseases s The recent emphasis on bioterrorism: important truth about infectious diseases Even without the element of intentional terror, diseases are a huge source of human suffering--and a tremendously destabilizing force Nearly half of the world's premature deaths (deaths under the age of 45) are caused by infectious diseases Some 30 million infants in developing countries remain unprotected by the lifesaving childhood vaccines that in the rest of the world are administered routinely; a million die each year from measles alone Chotani, 2003 Pathogens of BT do threaten humanity but let us NOT loose sight of the naturally occurring microbes that threaten billions of people in a world weakened by poverty, war, lack of clean water, and inattention specially during wars & complex humanitarian emergencies Chotani, 2003 Thank You Chotani, 2003 ...
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