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Gram-negative Cocci Coccobacilli

kristopher
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Gram-negative Cocci Coccobacilli

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    1. Gram-negative Cocci & Coccobacilli Neisseria meningitidis Neisseria gonorrhoeae Haemophilus influenzae Bordetella pertussis Pasteurella multocida

    2. N. meningitidis Versus N. gonorrhoeae N. meningitidis Glucose + Maltose + Capsule + Causes meningitis N. gonorrhoeae Glucose + Maltose - Capsule - Causes gonorrhea

    4. N. gonorrhoeae Major Virulence Factors Pili Mediate attachment Cause phase variation Antigenic variation ? lack of immunity Por protein ? prevention of phagolysosomal fusion LOS = Endotoxin IgA protease

    5. Epidemiology Humans are the only host Second most common STD (2002: 352,000 cases in the U.S.) ??? In adolescents Asymptomatic carriage: women > men Disease: men > women

    6. Gonorrhea Gonorrhea in the USA: 1970-2001 Urethritis in men PID in women Arthritis in men and women Ophthalmia neonatorum in newborns

    7. Pathogenesis & Clinical Manifestations Primary site: Urethra, vagina Men: Urethritis Women: Inflammation of the endocervix Purulent vaginal discharge Irregular intermenstrual bleeding PID ? Scarring ? Infertility Babies: Ophthalmia neonatorum

    11. Other Sites Anus/Rectum ? Proctitis Throat ? Pharyngitis Joints ? Arthritis, especially in young, sexually active persons

    13. Laboratory Diagnosis of N. gonorrhoeae Gram stain of the urethral discharge Culture: Thayer-Martin agar Glu+, malt-, sucrose- DNA probe

    16. Treatment & Prevention Ceftriaxone Mixed infection with Chlamydia trachomatis: Add tetracycline Prevention: Nonspecific (e.g., condoms)

    17. N. meningitidis Major Virulence Factors Capsule: Virulence factor Antigen that defines 13 serogroups Antigen detected in the CSF Antigen included in vaccine OMP LPS IgA protease

    18. Epidemiology Carriage: As high as 40% among certain groups of people Children (6 mo - 2 yrs) are more susceptible Serogroup B: The most prevalent in the U.S. 2000: 2,000 cases 2001: 2,300 cases 2002: 1,800

    19. Pathogenesis and Diseases Capsule and LPS Attachment to nonciliated cells LPS-mediated damage to ciliated cells Invasion of the submucosa Meningitis: Fever; Headache; Stiff Neck; ?PMNs in the CSF Meningococcemia ? DIC, Shock, Waterhouse-Friderichsen Syndrome

    20. QUIZ Physicians are issuing the warning that there is at least one side effect with Viagra…. Those who don’t swallow the pill quickly and with plenty of water get stiff neck

    22. Laboratory Diagnosis of N. meningitidis Specimen: CSF Direct exam: G- kidney-shaped diplococci Rapid detection: latex agglut. Culture: BAP, CHOC OX+, Glu+, Mal+

    25. Treatment & Prevention Penicillin Quadrivalent meningococcal polysaccharide vaccine: group A, C, Y, & W135 Children > 2 years, military recruits, college freshmen etc. Group B excluded due to low immunogenicity

    26. Haemophilus influenzae General Characteristics Gram-negative Pleomorphic Nonmotile coccobacillus X and V factor requirement

    27. Virulence Factors LPS OMP Capsule Virulence factor Antigen that defines serotype Antigen detected in the CSF Antigen included in the vaccine IgA protease

    28. Epidemiology Part of normal flora Incidence in the past: 8000 cases per year Incidence in 2002: 1,743 cases Kids < 5 y-old: 200 cases Decreased dramatically due to Hib vaccine

    31. Nonrespiratory Diseases Cellulitis Arthritis

    32. Laboratory Diagnosis of H. influenzae Culture: X and V factor requirement Antigen detection test

    33. Treatment & Prevention Otitis media and sinusitis: Ampicillin Trimethoprim-sulfamethoxazole Meningitis: Ceftriaxone Hib Vaccine

    34. Gram-Negative Coccobacilli Pasteurella multocida Bordetella pertussis

    35. Pasteurella multocida Short coccobacillus Encapsulated Stains bipolarly Part of normal flora in the mouths of domestic cats and dogs Transmission: through bites

    36. Pathogenesis and Clinical Manifestations Capsule is a virulence factor Endotoxin Exotoxin (PMT): disrupts cellular metabolism in the skin, connective tissue, fat, bone Rapid onset cellulitis at the bite site Osteomyelitis Diagnosis Bipolar staining Sick TSI Indole + Treatment: Penicillin

    37. Bordetella pertussis Small coccobacillus Encapsulated Obligate pathogen Infects humans only Transmission: via aerosol Highly contagious Occurs primarily in infants and young children Worldwide distribution

    38. Virulence Factors Filamentous hemagglutinin (protein on the pili) ? attachment Pertussis toxin ? Adenylate cyclase? ? cAMP ? Adenylate cyclase Tracheal cytotoxin

    39. Pathogenesis Attachment to the cilia of the epithelial cells in the upper airways How? With the help of filamentous hemagglutinin No invasion Pertussis toxin: Mucus secretion Lymphocytosis

    40. Clinical Manifestations Whooping Cough Tracheobronchitis Severe paroxysmal cough Duration: 1-4 weeks Death usually due to pneumonia

    41. Lab Diagnosis Nasopharyngeal Swabs Bordet-Gengou medium Agglutination in specific antiserum IFA

    44. Treatment and Prevention Erythromycin DPT Acellular Five Antigens (Genetically modified pertussis toxoid etc.)

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