Review from last lecture

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Review from last lecture

• Skin Infections
• Contrasting Staph aureus with Strep pyogenes
• Folliculitis, boils and carbuncles
• Rocky mountain spotted fever (R. rickettsii)
• Lyme disease (B. burgdorferi)
• Anthrax (Bacillus anthracis)
• Bacterial infections of Wounds
• Tetanus (C. tetani)
• Gangrene (C. perfringens)
• Burn infections (P. auerginosa)
• Actinomycosis (A. israelii)

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Sexually-transmitted Diseases
Denise Kirschner,PhD Dept of Micro/Immuno MICRO
532 Nov 29, 2001
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Outline

• Epidemiological principles of STDs
• UTI/Bladder infections
• Infections of mucosal surfaces
• Neisseria gonorrhea and Chlamydia trachomatis
• Ulcerative Infections
• Syphilis (T. pallidium) and Chancroid (H. ducreyi)

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General uro-genital tract information

• More female infections that males
• Urine is sterile
• Above bladder entrance-sterile, below lots of IM
  Lactobacillus, Staphylococcus, Cornybacterium,
  Haemophilus, Streptococcus, Bacteriodes
• Urinary tract infections (UTI)
• More than 100,000 bacteria/ml indicated
• Bladder infection
• Catherization is the major cause of infection
  (usually IM)
• Intercourse (for women)

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Sexually-transmitted Diseases
Mucosal infections
Proliferative infections
papillomavirus
gonorrhea
chlamydia
Systemic infections
HIV
Ulcerative infections
hepatitis B
herpes simplex
syphilis
chancroid
LGV
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Epidemiologic Principles of STDs
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Occurrence of STDs in the U.S.
Disease Incidence Prevalence
--
Chlamydia
4,000,000
--
Gonorrhea
1,400,000
Papillomavirus
800,000
45,000,000
Herpes simplex
300,000
30,000,000
Syphilis (primary)
50,000

(all stages)
100,000
100,000
HIV
70,000
1,500,000
Chancroid
4,000
?
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Trends in common STDs
500
400
chlamydia
gonorrhea
syphilis
300
chancroid
200
60
40
100
20
0
1950
1960
1970
1980
1990
1995
1980
1990
1995
Year
Note 60 of all N. gonorrhea infection are ages
15-24
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Determinants of STD Morbidity

• Rate of transmission
• Sexual behavior (rate of new partner acquisition)
• Duration of infectivity

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Factors That Affect the Transmission of STDs
Age
Gender
Genetic susceptibility
Sexual practices
Contraceptive and "hygienic" practices
Circumcision
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Determinants of the Duration of Infectivity in
STDs

• Etiologic agent
• tendency to asymptomatic carriage
• antimicrobial resistance
• Access and utilization of the health care system
• Compliance with therapy
• Contact tracing

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Theoretical Structure of an STD Core Group
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PPNG in Colorado Springs, Dec. 1989 - Dec. 1991
- not gang-related
- gang-related
C A S E S
D J F M A M J J A S O N D J F M A M J J A S O N D
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PPNG Outbreak, Colorado Spgs., 1989-91

• 56 cases in a 2-year period
• Traced to a network of 578 persons
• 410 (218 males and 192 females) were affiliated
  with a street gang that moved to the area in May
  1988.
• Mean age females (19.7 yrs) males (21.5 yrs)
• Prominent behaviors among females multiple
  partners, heavy crack use, drugs for sex

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CO-INFECTIONS
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Relevance of STD Co-infections

• May identify a core group member
• i.e., a "sentinel event"
• STDs increase transmission of HIV
• ulcerative and mucosal infections only
• Effect of HIV on expression of STDs
• accelerates HPV-associated tumors
• facilitates spread of gonococcus
• alters the natural course of syphilis
• Presumptive therapy
• 80-90 of college men with 1 STD have others (50
  with Chlamydia)

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Infections of mucosal surfaces
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Infections caused by gonococci and chlamydiae

• urethritis
• cervicitis
• epididymitis
• proctitis
• pharyngitis
• eye infection

gtgt
gt
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Epidemiologic characteristics of chlamydial and
gonococcal infections
GONOCOCCUS CHLAMYDIA
PATIENT AGE SEXUAL HISTORY ASX
INFECTION (male) ASX INFECTION (female)
teenagers gt young adults usually acquired
from a recent contact 5 of
infected males ( higher in some areas)
50 - 80 of infected females
teenagers gt young adults may have been
acquired in the remote past 50 of
infected sexual partners 50 of
infected sexual partners
ASXasymptomatic
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Microbiology of gonorrhea

• Strict human pathogen
• Gram-negative diplococcus
• Adherent- pilus (antigenic variation)
• IgA protease (cleaves IgA)
• Oxidase-positive
• Fastidious growth
• Modified Thayer-Martin media (VCN)

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Virulence determinants of Neisseria gonorrhoeae

• pilus colonization factor--gt antigenic variation
• opa proteins-------------------gt phase variation
• lipooligosaccharide---------gtantigenic variation
• IgA1 protease
• transferrin/lactoferrin binding proteins
• intracellular environment?

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Treatment of gonococcal infections

• PPNG
• Tetracycline resistance
• Quinolone resistance
• Single-dose treatment options for uncomplicated
  disease
• 1944 105 units of penicillin
• 1970 107 units
• Resistance (R plasmids)
• PPNG strain

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Microbiology of Chlamydia trachomatis

• Obligate intracellular bacteria
• Not G/G- (lacks part of LPS)
• Complex, 2-stage life cycle
• Elementary body (spore like)
• Reticulated body (vegetative like)
• Treatment antibiotics tetracyclines (not
  penicillin-why?)

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Chlamydial infections

• urethritis (NGU)
• epididymitis
• proctitis
• mucopurulent cervicitis
• pelvic inflammatory disease
• trachoma (serotypes A-C)
• LGV (L1, L2, L3)

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50-60 of women with infertility have serologic
evidence of chlamydia or gonococcus, but no
history of symptoms!
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Ulcerative infections
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Frequency of genital ulcer infections
HSVgtgtsyphilisgtgtchancroid
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Distinguishing features of genital ulcers

• anatomical location
• multiplicity
• pain
• induration

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Microbiology of syphilis

• Treponema pallidum
• spirochete -- labile spiral bacterium with axial
  filaments
• man is the only recognized host
• non-cultivable
• Gram-negative like

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T. pallidum darkfield examination
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reactive cases
iary ge
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Manifestations of 1 Syphilis

• Chancre (may be unnoticed)
• painless, but tender
• indurated
• highly contagious
• rapid dissemination
• motility of the organism?
• Congenital

• MANIFESTATIONS OF SECONDARY SYPHILIS
• Rash
• Lesions
• mucous patches
• Fever

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Natural history of secondary syphilis
spontaneous resolution
1/3
Secondary infection
1/3
infected without clinical disease
1/3
tertiary syphilis Neurosyphilis DTH Organisms
rare
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Syphilis- principles of treatment

• T. pallidum is exquisitely sensitive to
  penicillin
• Dosing and penicillin formulation used depends on
  the stage of the disease

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Microbiology of chancroid

• Haemophilus ducreyi
• Gram-negative coccobacilli
• fastidious and labile
• Diagnosis is usually clinical, by exclusion of
  other agents of genital ulcers

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Epidemiology and treatment of chancroid

• CDC reported a 10-fold increase in incidence from
  1978 - 1987
• 10 of patients are co-infected with either HSV
  or T. pallidum
• Males gtgt females
• Occurs in sustained, urban outbreaks
• Associated with female commercial sex workers and
  sex-for-drugs trade
• TREATMENT sensitive to ceftriaxone or
  azithromycin in single dose