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)

Sexually-transmitted Diseases

Denise Kirschner,PhDDept of Micro/ImmunoMICRO 532 Nov 29, 2001

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)

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)

Mucosal infections

Ulcerative infections

Proliferative infections

Sexually-transmitted DiseasesSexually-transmitted Diseases

• gonorrhea• chlamydia

• herpes simplex• syphilis• chancroid• LGV

• papillomavirus

Systemic infections• HIV• hepatitis B

Epidemiologic Principles of STDs

Disease Incidence Prevalence ChlamydiaGonorrheaPapillomavirusHerpes simplexSyphilis (primary) (all stages)HIVChancroid

4,000,0001,400,000 800,000 300,000 50,000 100,000 70,000 ~4,000

-- --45,000,00030,000,000

100,000 1,500,000 ?

Occurrence of STDs in the U.S.

Trends in common STDs

Year

0

100

200

300

400

500

1950 1960 1970 1980 1990 1995

chlamydiagonorrheasyphilischancroid

20

40

60

1980 1990 1995

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

pilus colonization factor--> antigenic variation

opa proteins-------------------> phase variation lipooligosaccharide--------->antigenic

variation IgA1 protease transferrin/lactoferrin binding proteins intracellular environment?

Treatment of gonococcal infectionsTreatment of gonococcal infections

PPNG Tetracycline resistance Quinolone resistanceSingle-dose treatment options

for uncomplicated disease: 1944 10^5 units of

penicillin 1970 10^7 units Resistance (R plasmids) PPNG strain

PPNG Tetracycline resistance Quinolone resistanceSingle-dose treatment options

for uncomplicated disease: 1944 10^5 units of

penicillin 1970 10^7 units Resistance (R plasmids) PPNG strain

Microbiology of Chlamydia trachomatisMicrobiology 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?)

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?)

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

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