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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Review from last lecture Skin Infections: Contrasting Staph aureus with Strep pyogenes Folliculitis, boils and carbuncles Rocky mountain spotted fever.
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Review from last lecture Skin Infections:
Contrasting Staph aureus with Strep pyogenes Folliculitis, boils and carbuncles
Note: 60% of all N. gonorrhea infection are ages 15-24
Determinants of STD Morbidity
Rate of transmission Sexual behavior (rate of new partner acquisition)
Duration of infectivity
Factors That Affect the Transmission of STDs:Factors That Affect the Transmission of STDs:
• Age• Gender• Genetic susceptibility• Sexual practices• Contraceptive and "hygienic" practices• Circumcision
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
Theoretical Structure of an STD Core Group
PPNG in Colorado Springs, Dec. 1989 - Dec. 1991
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
CASES
- not gang-related
- gang-related
PPNG Outbreak, Colorado Spgs., 1989-91
56 cases in a 2-year periodTraced 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
CO-INFECTIONS
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)
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)
Infections of mucosal surfaces
Infections caused by gonococci and chlamydiaeInfections caused by gonococci and chlamydiae urethritis cervicitis epididymitis proctitis pharyngitis eye infection
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Epidemiologic characteristics of chlamydial and gonococcal infections
GONOCOCCUS CHLAMYDIA
PATIENT AGE SEXUAL HISTORY
ASX INFECTION (male)
ASX INFECTION (female)
teenagers > young adults
usually acquired from a recent contact
~ 5% of infected males ( higher in some areas) 50 - 80% of infected females
teenagers > young adults
may have been acquired in the remote past
~ 50% of infected sexual partners
~ 50% of infected sexual partners
ASX=asymptomatic
Microbiology of gonorrheaMicrobiology 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)
Virulence Virulence determinants of determinants of Neisseria gonorrhoeaeNeisseria gonorrhoeae
50-60% of women with 50-60% of women with infertility have serologic infertility have serologic evidence of chlamydia or evidence of chlamydia or gonococcus, but gonococcus, but nono history history of symptoms!of symptoms!
Ulcerative infections
Frequency of genital Frequency of genital ulcer infectionsulcer infections
HSV>>syphilis>>chancroidHSV>>syphilis>>chancroid
Distinguishing features of genital ulcers
anatomical location multiplicity pain induration
Microbiology of syphilisMicrobiology of syphilis Treponema pallidum spirochete -- labile spiral
bacterium with axial filaments man is the only recognized
host non-cultivable Gram-negative like
Treponema pallidum spirochete -- labile spiral
bacterium with axial filaments man is the only recognized
host non-cultivable Gram-negative like
T. pallidum darkfield examination
% reactive cases
iaryge
Manifestations of 1° Syphilis Chancre (may be unnoticed)
painless, but tender indurated highly contagious rapid dissemination
motility of the organism? Congenital
MANIFESTATIONS OF SECONDARY SYPHILISRashLesions
mucous patchesFever
Natural history of Natural history of secondary syphilissecondary syphilis
Secondary infection
spontaneous resolution
infected withoutclinical disease
tertiary syphilis:NeurosyphilisDTHOrganisms rare
1/3
1/3
1/3
Syphilis- principles of Syphilis- principles of treatmenttreatment
T. pallidum is exquisitely sensitive to penicillin
Dosing and penicillin formulation used depends on the stage of the disease
Microbiology of Microbiology of chancroidchancroid Haemophilus ducreyi Gram-negative coccobacilli fastidious and labile Diagnosis is usually clinical,
by exclusion of other agents of genital ulcers
Haemophilus ducreyi Gram-negative coccobacilli fastidious and labile Diagnosis is usually clinical,
by exclusion of other agents of genital ulcers
Epidemiology and Epidemiology and treatment of chancroidtreatment 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 >> 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