Medical Microbiology
 Systemic bactreiology
           Gram +ve cocci
             Lecture-7
                 Dr. Saleh M ...
Koch's postulates                     Sporatic disease
Pathology
Epidemiology                          Acute disease
Etiol...
Streptococcus pneumoniae

       Pneumonia



                       3
- Causes 60-70% of all bacterial
  pneumonias

- Small, lancet-shaped cells
  arranged in pairs and short
  chains

- Cult...
S. pneumoniae
- All pathogenic strains form large capsules –
  major virulence factor
- Specific soluble substance (SSS) v...
Epidemiology and Pathology
- 5-50% of all people carry it as normal flora in the
   nasopharynx; infections are usually en...
Diagnosing Streptococcus pneumoniae




                                      7
The course of bacterial pneumonia




                                    8
View of ear anatomy indicating route
             of infection




                                       9
Cultivation and Diagnosis

-   Gram stain of specimen – presumptive
    identification

-   Quellung test or capsular swel...
Treatment and Prevention
Traditionally treated with penicillin G or V
Increased drug resistance
Two vaccines available for...
Gram nigative cocci

Family Neisseriaceae




                       12
Family Neisseriaceae
Gram-negative cocci

Residents of mucous membranes of warm-
 blooded animals

Genera include Neisseri...
Genus Neisseria
- Gram-negative, bean-shaped, diplococci
- None develop flagella or spores
- Capsules on pathogens
- Pili
...
Neisseria Gonorrhoeae:
          The Gonococcus
Causes gonorrhea, an STD
Virulence factors:
  - Fimbriae, other surface mo...
Epidemiology and Pathology
- Strictly a human infection
- In top 5 STDs
- Infectious dose 100-1,000
- Does not survive mor...
Comparative incidence of reportable
         infectious STDs




                                  17
Gonorrhea
Infection is asymptomatic in 10% of males and
  50% of females
Males – urethritis, yellowish discharge, scarring...
Gonorrheal damage to the male reproductive
                  tract




                                        19
Ascending gonorrhea in women




                               20
Gonorrhea in Newborns
Infected as they pass through birth canal

Eye inflammation, blindness

Prevented by prophylaxis imm...
Diagnosis and Control
Gram stain – Gram-negative intracellular
  (neutrophils) diplococci from urethral, vaginal,
  cervic...
Gram stain of urethral pus




                             23
Neisseria Meningitidis: The
          Meningococcus
Virulence factors:
  - Capsule
  - Adhesive fimbriae
  - IgA protease
...
Epidemiology and Pathogenesis
Prevalent cause of meningitis; sporadic or
  epidemic

Human reservoir – nasopharynx; 3-30% ...
Epidemiology and Pathogenesis …


Disease begins when bacteria enter bloodstream,
  cross the blood-brain barrier, permeat...
Dissemination of the meningococcus from
      a nasopharyngeal infection




                                      27
One clinical sign of meningococcemia




                                       28
Clinical Diagnosis
Gram stain CSF, blood, or asopharyngeal
 sample

Culture for differentiation

Rapid tests for capsular ...
Treatment and Prevention
Treated with IV penicillin G, cephalosporin

Prophylactic treatment of family members,
  medical ...
31
Other Gram-Negative Cocci and
           Coccobacilli
Genus Branhamella
  - Branhamella catarrhalis – found in nasopharynx...
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Microbiology lec6

  1. 1. Medical Microbiology Systemic bactreiology Gram +ve cocci Lecture-7 Dr. Saleh M Y OTH PhD Medical Molecular Biotechnology and Infectious Diseases 013/10/2010 IMS - MSU
  2. 2. Koch's postulates Sporatic disease Pathology Epidemiology Acute disease Etiology Chronic disease Infection Latent (recurrent) disease Disease Pathogen Local infection Invasiveness Systemic, generalized infection Opportunist Focal infection Reservoirs Primary infection Carrier Secondary infection Communicable (contagious) diseases Inapparent, subclinical infection Noncommunicable infectious diseases Nosocomial infections Direct contact transmission Bacteremia, viremia Indirect contact transmission Septicemia Fomite Toxemia Vectors Symptoms Droplet (nuclei) transmission Portal of entry Epidemic Portal of exit Pandemic Stages of disease: Endemic Incubation period Sporadic Disease Period of illness (invasive period) Convalescence 2
  3. 3. Streptococcus pneumoniae Pneumonia 3
  4. 4. - Causes 60-70% of all bacterial pneumonias - Small, lancet-shaped cells arranged in pairs and short chains - Culture requires blood or chocolate agar - Growth improved by 5-10% CO2 - Lack catalase and peroxidases – cultures die in O2 4
  5. 5. S. pneumoniae - All pathogenic strains form large capsules – major virulence factor - Specific soluble substance (SSS) varies among types - 90 different capsular types have been identified - Causes pneumonia and otitis media 5
  6. 6. Epidemiology and Pathology - 5-50% of all people carry it as normal flora in the nasopharynx; infections are usually endogenous - Very delicate, does not survive long outside of its habitat - Young children, elderly, immunocompromised, those with other lung diseases or viral infections, persons living in close quarters are predisposed to pneumonia - Pneumonia occurs when cells are aspirated into the lungs of susceptible individuals - Pneumococci multiply and induce an overwhelming inflammatory response - Gains access to middle ear by way of eustachian 6 tube
  7. 7. Diagnosing Streptococcus pneumoniae 7
  8. 8. The course of bacterial pneumonia 8
  9. 9. View of ear anatomy indicating route of infection 9
  10. 10. Cultivation and Diagnosis - Gram stain of specimen – presumptive identification - Quellung test or capsular swelling reaction - α-hemolytic; optochin sensitivity, bile solubility, inulin fermentation 10
  11. 11. Treatment and Prevention Traditionally treated with penicillin G or V Increased drug resistance Two vaccines available for high risk individuals: - Capsular antigen vaccine for older adults and other high risk individuals – effective 5 years - Conjugate vaccine for children 2 to 23 months 11
  12. 12. Gram nigative cocci Family Neisseriaceae 12
  13. 13. Family Neisseriaceae Gram-negative cocci Residents of mucous membranes of warm- blooded animals Genera include Neisseria, Branhamella, Moraxella Two primary human pathogens: - Neisseria gonorrhoeae (STD) - Neisseria meningitidis 13
  14. 14. Genus Neisseria - Gram-negative, bean-shaped, diplococci - None develop flagella or spores - Capsules on pathogens - Pili - Strict parasites, do not survive long outside of the host - Aerobic or microaerophilic - Oxidative metabolism - Produce catalase and cytochrome oxidase - Pathogenic species require enriched complex media and CO2 14
  15. 15. Neisseria Gonorrhoeae: The Gonococcus Causes gonorrhea, an STD Virulence factors: - Fimbriae, other surface molecules for attachment; slows phagocytosis - IgA protease – cleaves secretory IgA 15
  16. 16. Epidemiology and Pathology - Strictly a human infection - In top 5 STDs - Infectious dose 100-1,000 - Does not survive more than 1-2 hours on fomites 16
  17. 17. Comparative incidence of reportable infectious STDs 17
  18. 18. Gonorrhea Infection is asymptomatic in 10% of males and 50% of females Males – urethritis, yellowish discharge, scarring, and infertility Females – vaginitis, urethritis, salpingitis (PID) mixed anaerobic abdominal infection, common cause of sterility and ectopic tubal pregnancies Extragenital infections – anal, pharygeal, conjunctivitis, septicemia, arthritis 18
  19. 19. Gonorrheal damage to the male reproductive tract 19
  20. 20. Ascending gonorrhea in women 20
  21. 21. Gonorrhea in Newborns Infected as they pass through birth canal Eye inflammation, blindness Prevented by prophylaxis immediately after birth 21
  22. 22. Diagnosis and Control Gram stain – Gram-negative intracellular (neutrophils) diplococci from urethral, vaginal, cervical, or eye exudate – presumptive identification 20-30% of new cases are penicillinase-producing PPNG or tetracycline resistant TRNG Combined therapies indicated Recurrent infections can occur Reportable infectious disease 22
  23. 23. Gram stain of urethral pus 23
  24. 24. Neisseria Meningitidis: The Meningococcus Virulence factors: - Capsule - Adhesive fimbriae - IgA protease - Endotoxin 12 strains; serotypes A, B, C cause most cases 24
  25. 25. Epidemiology and Pathogenesis Prevalent cause of meningitis; sporadic or epidemic Human reservoir – nasopharynx; 3-30% of adult population; higher in institutional settings High risk individuals are those living in close quarters, children 6 months-3 years, children and young adults 10-20 years 25
  26. 26. Epidemiology and Pathogenesis … Disease begins when bacteria enter bloodstream, cross the blood-brain barrier, permeate the meninges, and grow in the cerebrospinal fluid Very rapid onset; neurological symptoms; endotoxin causes hemorrhage and shock; can be fatal 26
  27. 27. Dissemination of the meningococcus from a nasopharyngeal infection 27
  28. 28. One clinical sign of meningococcemia 28
  29. 29. Clinical Diagnosis Gram stain CSF, blood, or asopharyngeal sample Culture for differentiation Rapid tests for capsular polysaccharide 29
  30. 30. Treatment and Prevention Treated with IV penicillin G, cephalosporin Prophylactic treatment of family members, medical personnel, or children in close contact with patient Primary vaccine contains specific purified capsular antigens 30
  31. 31. 31
  32. 32. Other Gram-Negative Cocci and Coccobacilli Genus Branhamella - Branhamella catarrhalis – found in nasopharynx: significant opportunist in cancer, diabetes, alcoholism Genus Moraxella - Bacilli – found on mucous membranes Genus Acinetobacter 32
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