chapter 21 module 8 Flashcards
21.1 The Genitourinary Tract and Its Defenses
Urinary Tract
job of removing substances from the blood, regulating certain processes, and forming urine and transporting it out of the body
includes: kidneys, ureters, bladder, and urethra
Genital system
reproduction is its major function
kidneys
remove metabolic wastes from blood, a sophisticated filtration system
Ureters
tubular organs extending from each kidney to the bladder
Bladder
a collapsible organ that stores urine and empties it into the urethra
Urinary Tract Defenses
- flushing of urine out of the system
- flow of urine also encourages desquamation of epithelial cells lining the urinary tract (so also shedding microorganisms)
- epithelial cells in urinary tract have special chemicals on their surface that prevent GI biota from gaining foothold in the urinary tract
- urine is acidic, and contains lysozyme and lactoferrin (iron binding protein that inhibits bacterial growth)
- secretory IgA specific for previously encountered microbes can be found in urine
–> biggest microbial threat is normal biota of GI tract
Male Repro system + defenses
produces, maintains, and transports sperm cells and is source of male sex hormones
- -> testes, epididymides (coiled tubes leading out of the testes), these ach terminates in a vas deferens which combines with the seminal vesicle and terminates in the ejaculatory duct –> contents of ejaculatory duct empty into urethra during ejaculation
- -> prostate is walnut shaped gland at the base of the urethra
External organs: scrotum (containing the testes), and penis
Defenses: flushing action of urine
Female Repro System + defenses
uterus, fallopian tubes (uterine tubes), ovaries, vagina
–> very important tissue of the female repro system is the cervix, which is the lower one third of the uterus that connects to the vagina, and is the opening to the uterus, cervix is common site of infection in the female reproductive tract
Defenses: very over the lifetime of a woman
- vagina is lined with mucous membranes and thus, has the protective covering of secreted mucus
- -> during childhood and after menopause this mucus is the major innate defense of this system, secretory IgA antibodies specific for any previously encountered infections will also be present on these surfaces
During a woman’s repro. years:
-major portion of defense is provided by changes in the pH of the vagina brought about by the release of estrogen
–>this hormone stimulates the vaginal mucosa to secrete glycogen, which certain bacteria can ferment into acid, lowering the pH of the vagina to between 4.2-5.0
(before puberty, a girl produces little estrogen and little glycogen and has a vaginal pH of about 7)
-the change in pH beginning in adolescents results in a vastly different normal biota in the vagina
Childbearing years:
-normal biota of women in their childbearing years is thought to prevent the establishment and invasion of microbes that might have the potential to harm a developing fetus
21.2 Normal Biota of the Genitourinary Tract
Urinary Tract Biota
research is showing that the urinary tract harbors a move diverse microbiota then we used to think
- Lower urethra: has a well-established microbiota
- Upper urethra: few types of microbiota and lower abundance
- -> varies among men and women and individual people
- Women’s short urethra = high chance of UTI from GI biota
Genital Biota : Male Genital Tract
Penis:
outer surface of penis is colonized by Pseudomonas and Staphylococcus species–aerobic bacteria
–> is an uncircumcised penis, the area under the foreskin is colonized by anaerobic gram-negative bacteria
Some of the biota is the same as urethra since the male urethra is inside the penis
- > Uncircumcised penis has much larger and more diverse microbes, and more anerobic species
- After sexual activity begins, microbes associated with STIs can sometimes become long-term residents
Genital Biota : Female Genital Tract
uterus, ovaries, fallopian tubes previously thought to be sterile
–> next gen sequencing shows that upper genital tract has occasional “trespassers” or possibly more permanent residents
Before puberty and after menopause, the pH of vagina is close to neutral and vagina harbors a biota that is similar to that found in the urethra
After puberty, estrogen production leads to glycogen release in the vagina, resulting in acidic pH
- -> Lactobacillus species thrive in the acidic environment and contribute to it by converting sugars to acids
- their predominance in the vagina, combined with the acidic environment, discourages the growth of many microorganisms
NOTE: Candida albicans is also present in low levels in the healthy female reproductive tract
–> when normal vaginal microbiota is altered and unable to keep Candida albicans in check, an overgrowth of fungus may occur = yeast infection
Urinary Tract Biota (BOTH SEXES)
Nonhemolytic streptococcus, Staphylococcus, Corynebacterium, Lactobacillus, Prevotella, Veillonella, Gardnerella
Urinary Tract Defenses (BOTH SEXES)
flushing action of urine, specific attachment sites not recognized by most nonnormal biota, shedding of urinary tract epithelial cells, secretory IgA, lysozyme, and lactoferrin in urine
Female Genital Tract during childbearing years : biota + defenses
biota: variable, but often Lactobacillus predominates; also Prevotella, Sneathia, Streptococcus, and Candida albicans
defense: acidic pH, mucus secretions, secretory IgA
21.3 Urinary Tract Diseases Caused by Microorganisms
UTIs (2 diseases in this section)
UTIs, result from invasion of the urinary system by bacteria or other microorganisms
(although urine flow flushes microbes, it also serves as a good medium for growing microorganisms)
Leptospirosis, by contrast, is a spirochete-caused disease transmitted by contact of broken skin or mucous membranes with contaminated animal urine
Highlight disease: UTI
when urine flow is reduced or bacteria are accidentally introduced into the bladder, an infection of that organ can occur (known as cystitis)
; occasionally the infection can also affect the kidneys, which is called pyelonephritis
; if an infection is limited to the urethra, it is called urethritis
UTI S/S
cystitis is a disease of sudden onset
- pain
- frequent urges to urinate even when the bladder is empty
- burning pain accompanying urination, called dysuria
- urine can be cloudy due to presence of bacteria and WBCs
- may have an orange tinge from the presence of red blood cells (hematuria)
- low grade fever and nausea are frequently present
- If back pain is present and fever is high, it is an indication of kidney involvement (pyelonephritis)
- which can result in permanent damage to kidneys if not properly treated
–>if only bladder is involved, the condition is sometimes called acute uncomplicated UTI
UTI Causative Agents
important to distinguish between UTIs that are acquired in health care facilities and those acquired outside of HC settings
-> when acquired in HC settings they are almost always a result of catheterization, catheter-associated (CA-UTIs)
In 95% of UTIs, the cause is bacteria that are normal biota in the GI tract
- -> E. coli is by far the most common of these, accounting for approx. 80% of community-acquired UTIs; the species of E. coli that causes UTIs is the normal biota of GI, not the kind that causes diarrhea and other digestive tract illness
- -> Staphylococcus saprophyticus and other members of the bacterial family that contains E. coli, Enterobacteriaceae, especially Klebsiella pneumoniae, and Proteus mirablis are also common culprits
UTIs Transmission and Epidemiology
Community-acquired UTIs are nearly always “transmitted” NOT from person to person, but from one organ system to another, namely from the GI tract to the urinary system
much more common in women than men because of nearness of female urethral opening to anus and shorter urethral tract
- > many women experience “recurrent UTIs” = it is now known that some E. coli can invade deeper into the tissue of the urinary tract and avoid being destroyed by antibiotics
- -> they can emerge later to cause symptoms again (it is not clear how many “recurrent” infections are actually infections that reactivate in this way
*Now recommended to avoid/minimize the use of catheters
UTI Treatment
A drug called Nitrofurantoin (Macrobid) is most often used for UTIs of various etiologies
- > another nonantibiotic drug called phenazopyridine (Pyridium) if often administered simultaneously (this drug relieves the very uncomfortable symptoms of burning and urgency)
- —>some physicians are reluctant to administer this drug for fear of it masking worsening symptoms
- When Pyridium is used, it should only be used for a maximum of 2 days
- it is an azo dye and causes urine to turn a dark orange to red color
- may also color contact lenses
*A large number of E. coli strains are resistant to penicillin derivatives, so these should be avoided
Some representatives of the family Enterobacteriaceae have become resistant to carbapenem, and designated CRE (carbapenem-resistant Enterobacteriaceae)
UTI
E. coli
Cause Org: Escherichia coil (G-)
Trans: opportunism: transfer from GI tract (community-acquired) or environment or GI tract (via catheter)
V Factors: adhesins, motility
Culture/Dx: usually culture-based; antimicrobial susceptibilities always checked
Px: hygiene practices; in cases of CA-UTIs, limited catheter usage
Tx: usually Nitrofurantoin (Macrobid); members of family Enterobacteriaceae in Urgent Threat category of resistance
UTI
Staphylococcus saprophyticus
Cause Org: Staphylococcus saprophyticus (G+)
Trans: opportunism: transfer from GI tract (commnuity-acquired), or environment or GI tract (catheter)
V Factors: —
Culture/Dx: usually culture-based; antimicrobial susceptibilities always checked
Px: hygiene practices; in cases of CA-UTIs, limit catheter usage
Tx: usually Nitrofurantoin
UTIs other Enterobacteriaceae (Klebsiella pneumonia, Proteus mirablis) G-
Cause Org: other Enterobacteriaceae (Klebsiella pneumonia, Proteus mirablis) G-
Trans: opportunism: transfer from GI tract (community-acquired) or environment or GI tract (via catheter)
V Factors: —
Culture/Dx: usually culture-based; antimicrobial susceptibilities always checked
Px: hygiene practices; in cases of CA-UTIs, limit catheter usage
Tx: based on susceptibility testing; members of family Enterobacteriaceae in URGENT THREAT resistance category
Leptospirosis
zoonosis associated with wild animals and domesticated animals
- can affect kidney, liver, brain, and eyes
- -> considered in this section because it can have its major effects on the kidneys and because its presence in animal urinary tracts causes it to be shed into the environment through animal urine
Leptospirosis S/S
Leptospirosis has two phases:
- during the early, or leptospiremic, phase, the pathogen appears in the blood and CSF
- symptoms are fever, chills, headache, muscle aches, conjunctivitis, and vomiting - during the second phase, the blood infection is cleared by immune defenses
- period is marked by milder fever, headache due to leptospiral meningitis, and in rare cases, Weil’s Syndrome (kidney invasion, hepatic disease, jaundice, anemia, and neurological substances)
Leptospirosis Causative Agent
Leptospires are typical spirochete bacteria marked by tight, irregular, individual coils with a bend or hook at one or both ends
- Leptospira interrogans is the species that causes leptospirosis in humans and animals
- -> nearly 200 different serotypes of this species distributed among various animal groups, which accounts for extreme variations in the disease manifestations in humans
Leptospirosis Transmission and Epidemiology
infection occurs almost entirely through contact of skin abrasions or mucous membranes with animal urine or some environmental source containing urine
-in 1998, dozens of athletes competing in the swimming phase of a triathlon in Illinois contracted leptospirosis from the water
-common pathogen of Latin America and Asia
Leptospirosis Treatment
early treatment with Doxycycline, Penicillin G, or Ceftriaxone rapidly reduces symptoms and shortens the course of the disease
- -> but delayed therapy is less effective
- often spirochete diseases (such as syphilis) exhibit the same pattern of being susceptible to antibiotics early in the infection but less so later on in the infection
Leptospirosis Summary
Cause Org: Leptospira interrogans G-
Trans: vehicle: contaminated soil or water
V Factors: Adhesins, invasion proteins
Culture/Dx: In US, CDC will culture specimens
Px: avoiding contaminated vehicles
Tx: Doxycycline, Penicillin G, Ceftriaxone
21.4 Reproductive Tract Diseases Caused by Microorganisms
WHO reports there are one ___________ new STI cases every day worldwide
million
diseases in which the infectious agent causes an increase in fluid discharge in the male and female reproductive tracts; causative agents are transferred to new hosts when the fluids in which they live contact the mucosal surfaces of the receiving partner.
ie. trichomoniasis, gonorrhea, and Chlamydia
discharge diseases
Gonorrhea S/S
Male
Infection of the urethra elicits:
urethritis, painful urination, and a yellowish discharge, although a relatively large number of cases are ASYMPTOMATIC
–> most cases are limited to the urogenital tract, but can occasionally spread from the urethra to the prostate gland and epididymis
–> scar tissue formed in the spermatic ducts during healing of an invasive infection can render a man infertile
Female
Likely that infection will occur in both urinary and genital tracts
-mucopurulent (containing mucus or pus) or bloody vaginal discharge occurs in a minority of the cases, along with painful urination if the urethra is affected
-major complications occur when the infection ascends from the vagina and cervix to higher reproductive structures such as the uterus and fallopian tubes
–> one disease that can result from this progression is SALPINGITIS (inflammation of the fallopian tubes); infection may be isolated to tubes or include other parts of the upper repro. tract, termed PELVIC INFLAMMATORY DISEASE (PID)
—> can lead to blockage of tubes from scar tissue and cause sterility or ectopic pregnancies
Gonorrhea consequences outside of repro tract
in small number of cases, the gonococcus enters the bloodstream and is disseminated to the joints and skin
–> involvement of the wrist and ankle can lead to chronic arthritis and a painful, sporadic, papular rash on the limbs
rare: meningitis and endocarditis
risk of children born to gonococcal positive mothers
danger of being infected in the birth canal
- mothers are screened
- gonococcal eye infections are very serious and often result in keratitis, ophthalmia neonatorum, and even blindness
- -> universal precaution to prevent such complications is the use of antibiotic eye drops or ointments (usually erythromycin) for newborn babes
Gonorrhea Causative Agent
Neisseria gonorrhoeae is a pyogenic (pus-forming) gram neg diplococcus
-> appears as a pair of kidney or coffee bean shaped bacteria with their flat sides touching
Gonorrhea
Pathogenesis and V Factors
- use specific chemical groups on the tips of fimbriae to anchor themselves to mucosal epithelial cells
- -> once the bacterium attaches, it invades the cell and multiplies within the basement membrane
- fimbriae also play role in slowing down effective immunity
- -> fimbrial proteins are controlled by genes that can be turned on or off, depending on bacterium’s situation (phenotypic change is called PHASE VARIATION)
-fimbriae can rearrange themselves to different configurations and the antigenic variation confused the body’s immune system
- gonococcus possess enzyme called IgA protease
- -> can cleave IgA molecules stationed for protection on mucosal surfaces
- -> pieces of gonococcus outer membrane are shed during growth; “blebs” containing endotoxin probably play a role in pathogenesis because they can stimulate portions of the innate defense response, resulting in localized damage
Gonorrhea
Trans and Epi
except for neonatal infections, it is spread through some form of sexual contact
strictly human infection, ranked among most common sexually transmitted diseases
approx. 10% of infected males and 50% of infected females experience no symptoms and the infection is spread unknowingly
Gonorrhoeae
Culture/Dx
best method of dx is a PCR test of secretions
Gram stain of male secretions usually will yield visible gonococci inside polymorphonuclear cells, but this procedure is not considered sensitive enough to rule out infection if no bacteria are found
N. gonorrhoeae grows best in increased CO2
-very fragile, so best to inoculate it into media directly from the patient rather than using a transport tube
-produce catalase, enzymes for fermenting various carbs, and the enzyme cytochrome oxidase (which can be used for identification as well)
Gonorrhea
Prevention
no vaccine
-use condoms
Gonorrhea
Treatment
b/c those infected with N. gonorrhoeae are frequently coinfected with Chlamydia, tx recommendations include treating for both bacteria unless its presence has been ruled out
- Gonococcal Isolate Surveillance Project (GISP) - monitors the growing prevalence of antibiotic-resistant strains of N. gonorrhoeae
- -> every month in 28 local STD clinics around the country, gonorrhea isolates from the first 25 males diagnosed are sent to regional testing labs to look for urgent threat bacterial resistance
-recommended tx is two antibiotics simultaneously to try to slow the growth of antibiotic resistance
Chlamydia
genital Chlamydia trachomatis infection is the most common reportable infectious disease in the US
-many cases are asymptomatic = not good
Chlamydia S/S
Males:
- bacterium causes inflammation of the urethra,
- symptoms mimic gonorrhea: namely discharge and painful urination
- untreated infections may lead to epididymis
Females:
- may experience cervicitis, a discharge, and often salpingitis
- Pelvic Inflammatory disease is a frequent sequela of female chlamydial infection (more frequent then with gonorrhea)
- up to 75% of infections are asymptomatic (putting women at risk for PID b/c they don’t seek treatment)
- as a result of invasion of the lymphatic tissues a condition called lymphogranuloma venereum may occur
- -> headache, fever, muscle aches
- -> lymph nodes near the lesion fill with granuloma cells and become enlarged and tender
- —–> these “nodes” can cause long term lymphatic obstruction that leads to chronic, deforming edema or the genitalia or anus
babies born to Chlamydia infected mothers
can develop eye infections and also pneumonia if they become infected during the passage through the birth canal
- INFANT CONJUNCTIVITIS is the most prevalent form of conjunctivitis in the US
- antibiotic eye drops or ointments are applied to newborns’ eyes and work to eliminate both Chlamydia and N. gonorrhoeae
C. trachomatis
Causative Agent
C. trachomatis is a very small gram neg bacterium
- lives inside host cells as an obligate intracellular parasite
- all chlamydia species alternate between two stages (elementary body and reticular body)
Chlamydia
Pathogenesis and Virulence Factors
grows intracellularly (escapes certain factors of cell immune response)
unique cell wall that prevents phagosomes from fusing with the lysosome inside phagocytes
presence of bacteria inside cells causes cytokines to be released, and they provoke intense inflammation
–> this defensive response leads o most of the actual tissue damage in Chlamydia infection
Chlamydia
Transmission and Epidemiology
reservoir is human body
-adolescent women are more likely than older women to harbor the bacterium b/c it prefers to infect cells that are particularly prevalent on the adolescent cervix
transmitted through sexual contact and also vertically (can be passed on to babies as conjunctivitis and pneumonia)
Chlamydia
Culture/Dx:
PCR or ELISA
-urine test available (slightly less accurate for females than males)
Chlamydia
Treatment
CDC recommends annual screening for young women (often asymptomatic)
Doxycycline and/or azithromycin
- many patients become reinfected soon after (so recommended to be rechecked 3-4 months later after treatment)
- coinfection with gonorrhea should be assumed or treated similarly
- sexual partners should receive treatment too to prevent infection
Vaginitis and Vaginosis
S/S
vaginitis = inflammation of vagina characterized by some degree of vaginal itching (depending on etiologic agent); sometimes burning and discharge
vaginosis = similar to vaginitis but does not include significant inflammation
Vaginitis and Vaginosis
Causative agents
variety of bacteria and even protozoa can cause vaginitis, but most well known is fungus candida albicans (yeast infection)
Vaginitis and Vaginosis
Candida Albicans
dimorphic fungus that is normal biota in the majority of humans, living in low numbers on many mucosal surfaces such as the mouth, GI tract, vagina, and so on
–> causes vulvovaginal candidiasis
Culture/dx: wet prep or Gram stain
(presence of pseudohyphae in smear is clear indication that yeast is growing rapidly and causing infection
*can enter bloodstream and have high mortality rates but in otherwise healthy people they limit themselves to surface infections
Trans/Epi: nearly always opportunistic; disruptions of normal bacterial biota or even minor damage to mucosal epithelium of the vagina can lead to overgrowth of fungus
- -> disruptions may be mechanical such as trauma to the vagina, or chemical as in broad-spectrum antibiotics taken for other purposes
- -> women with HIV experience recurring yeast infections
- -> not likely to pass yeast infection onto sexual partner, but they may pass is back to you
Px and Tx: topical and oral azole drugs are used to treat vaginal candidiasis and many are available over the counter
Vaginitis and Vaginosis
Gardnerella Species
bacteria associated with a particularly common condition in women in their childbearing years; vaginosis (BV or bacterial vaginosis)
- -> despite absence of inflammatory response, a vaginal discharge is associated with condition and often has FISHY odor
- -> itching also common
- -> many women have this condition with no noticeable symptoms
Most likely result of shift from good bacteria (lactobacilli) to bad, one of those being Gardnerella vaginalis
- -> facultative anaerobe and gram positive (although in gram stain usually appears gram-negative) = gram variable in some texts
- -> prob mixed infection
- -> fishy odor comes from metabolic by-products of anaerobic metabolism by these bacteria
V Factors: mechanism of damage is not well understood, but some outcomes are
–> vaginosis can lead to sx described as well as PID, infertility, and rarely ectopic pregnancies; some babies born to mothers infected have low birth weights
Trans/Epi: condition may be associated with sex, but is not transmitted sexually
- changes in vaginal epithelium caused by semen, saliva, or penetration may contribute
- the low pH typical of vagina is usually higher in vaginosis
Culture/Dx: sometimes a simple stain of vaginal secretions is used
- in vaginosis some cells will appear to be completely covered in bacteria (these cells are called CLUE CELLS - and are a helpful diagnostic tool)
- can also be found on Pap smears
- -> sometimes genomic analyses are needed
Px and Tx: women who find condition uncomfortable or plan to become pregnant should be treated.
- women who use IUDs for contraception should be treated b/c IUDs can create passageway to upper repro tract
- usual tx is oral or topical METRONIDAZOLE or CLINDAMYCIN
Vaginitis and Vaginosis
Trichomonas vaginalis
small, pear-shaped PROTOZOA with four anterior flagella and an undulating membrane
- seems to cause asymptomatic infections (some experience long-term negative effects with this protozoa infection)
- no cyst form and does not survive long outside of host
- many cases asymptomatic and men seldom have symptoms
- women have vaginitis symptoms which include a white or green frothy discharge
- chronic infection can make a person more susceptible to other infections, including HIV
Culture/Dx: Pap smear, Gram stain, Culture = GOLD STANDARD
Tx: Metronidazole, tinidazole
D Feats: discharge may be frothy and green (or whiteish); one of CDC’s neglected parasite infections
Trans: since Trichomonas is a common biota in so many people, is it easily transmitted through sexual contact/ DIRECT CONTACT (STI)
- most common nonviral STI
- does not appear to undergo opportunistic shifts within the host (ie. to become symptomatic under certain conditions) BUT rather then protozoan causes symptoms when transmitted to a noncarrier
Prostatitis
inflammation of prostate gland; virtually always caused by bacterial infection
- bacteria are usually normal biota from GI tract and may have caused a previous UTI
- chronic prostatitis, often unresponsive to tx, can be caused by mixed biofilms of bacteria in the prostate
S/S: pain in groin and lower back, frequent urges to urinate, difficulty in urinating, blood in urine, painful ejaculation
Treatment: ciprofloxacin and levofloxacin; muscle relaxers, alpha blockers
Trans: endogenous transfer from GI tract otherwise unknown
Culture/Dx: digital rectal exam to examine prostate, culture or urine or semen
Genital Ulcer Diseases
three common infections can result in lesions (ulcers) on the genitals:
- syphilis
- chancroid
- genital herpes
–> having one of these infections can increase the chances of infection with HIV due to open lesions
Genital Ulcer Diseases
Syphilis
untreated syphilis is marked by distinct clinical stages designated as primary, secondary, and tertiary syphilis
–> disease also has latent periods of varying duration during which it is quiescent
spirochete appears in lesions and blood during primary and secondary stages, and therefore is transmissible during these times
- during the early latency period between secondary and tertiary syphilis it is also transmissible
- -> largely nontransmissible during “late latent” and tertiary stages
Genital Ulcer Diseases
Primary Syphilis
earliest indication of syphilis is appearance of a hard CHANCRE at the site of entry of the pathogen
CHANCRE = primary sore of syphilis that forms at the site of penetration by Treponema pallidum
–> b/c sores then to be painless they may escape notice especially when they are on internal surfaces
–> chancres heal spontaneously without scarring in 3-6 weeks (but healing is deceptive because the spirochete has escaped into the circulation and entering a period of tremendous activity)
Secondary Syphilis
about 3 weeks to 6 months after the chancre heals, the secondary stage appears
-by then most body systems have been invaded and signs and symptoms are more profuse and intense
Initial sx: fever, headache, and sore throat, followed by lymphadenopathy and a peculiar red or brown rash that breaks out on all skin surfaces, including palms of hands and soles of feet
- -> a persons hair often falls out
- -> like the chancre, the lesions contain viable spirochetes and disappear spontaneously in a few weeks
major complications of this stage can occur in bones, hair follicles, liver, eyes, brain, and can linger for months and years
Latency and Tertiary Syphilis
after resolution of secondary syphilis about 30% of infections enter a highly varies latent period that can last for 20 years or longer
-during latency, although antibodies to the bacterium are readily detected, the bacterium itself is not
- -> final stage of syphilis, tertiary syphilis, is relatively rare b/c of widespread use of antibiotics, but this stage is very damaging
- when a patient reaches this stage, numerous pathological complications occur in susceptible tissues and organs
- -> cardiovascular syphilis results from damage to the small arteries in the aortic wall = as fibers in the wall weaken, the aorta is subject to distention and fatal rupture (and potentially heart failure)
in one form of tertiary syphilis, painful swollen syphilitic tumors called gummas (nodular, infectious granuloma) develop in tissues such as the liver, skin, bone, and cartilage
- -> gummas are usually benign and only occasionally lead to death, but they can impair function
- -> neurosyphilis can involve any part of the nervous system but it shows affinity in the blood vessels in the brain, cranial nerves, and dorsal roots of the spinal cord
- —-> diverse results include convulsions, severe headaches, atrophy of the optic nerve, blindness, dementia, and a sign called ARGYLL-ROBERTON PUPIL (adhesions alone the inner edge of the iris that fix the pupil’s position into a small irregular hole)
Congenital Syphilis
syphilis bacterium can be pass into the placenta and carried throughout fetal tissues
- -> pathogens inhibit fetal growth and disrupt critical periods of development, with consequences ranging from mild to extreme (ie. stillbirth and miscarriage)
- -> infants often have nasal discharge, skin eruptions, bone deformation, and NS abnormalities, and Hutchinson’s Teeth
Syphilis
c. agent
Treponema pallidum
- spirochete
- gram neg cell wall
- coiled cell
- strict parasite with complex growth requirements
Syphilis
Pathogenesis and V Factors
brought into direct contact with mucous membranes or abraded skin and binds avidly by its hooked tip to the epithelium
–> it then multiplies and penetrates the capillaries nearby, and moves into circulation
Syphilis
Trans + Epi
humans are natural host of T. pallidum
- extremely fastidious and sensitive and cannot survive long outside of the host
- rapidly destroyed by heat, drying, disinfectants, soap, high oxygen tension, pH changes
- survives a few minutes to hours when protected by body secretions and about 36 hours when stored in blood
- risk of infection from an infected sexual partner is 12% to 30% per encounter
- rates increasing again in US since 2003
patients with syphilis often have concurrent infections with other STIs
and
coinfection with AIDS virus can be an especially deadly combination with a rapidly fatal course
Syphilis
Culture and Dx
detected using dark-field microscopy
-single negative test is not enough to include syphilis, repeat testing should be completed
common to use blood tests for diagnosis
best test is one which specifically reacts with treponemal antigens
RPR test (rapid plasma reagin) - tests for antigens that are not from the bacterium but that appear in the host during infection from bacterium ---> always coupled with immunoassay specific for treponemal antigens for accuracy
Syphilis
Prevention
condom
prevention programs that depend on detection and treatment of sexual contacts of syphilitic patients
tracing contacts
Syphilis
Treatment
in the past toxic compounds like mercury and arsenic were used to treat
current recommendations are for CIPROFLOXACIN or LEVOFLOXACIN
memory key: USE THE FLOX INSTEAD OF THE TOX
Syphilis
V Factor
Lipoproteins
Chancroid
Genital Ulcer Diseases
ulcerative disease that usually begins as a soft papule, or bump, at the point of contact
- develops into a “soft chancre” (in contrast to the hard syphilis chancre)m which is very painful in men, but may go unnoticed in women
- inguinal lymph nodes can become very swollen and tender
V factors: rule out other ulcer diseases; a hemolysin (exotoxin) may be an important piece in pathogenesis
Trans: direct contact (vertical transmission not documented); more common in uncircumcised men; may be asymptomatic
Causative Org: Haemophilus ducreyi (G-)
-pleomorphic rod
Treat: Ceftriaxone or azithromycin
Genital Herpes
Genital Ulcer Diseases
HSV-1 and HSV-2
S/S: person may notice no symptoms
- could cause single or multiple vesicles on the genitals, breasts, perineum, thigh, and buttocks (vesicles are small and are filled with clear fluid, and can be intensely painful to touch)
- appearance of lesions can come with malaise, anorexia, fever and bilateral swelling and tenderness in the groin
–> MAY have recurrent episodes of lesions after recovery from initial infection
Herpes of the newborn
HSV infections in the neonate and fetus can be very destructive and can be fatal
–> most cases occur when infants are contaminated by the mother’s reproductive tract immediately before or during birth
BUT have also be traced to hand transmission from the mother’s lesions to the baby
pregnant women with a hx of recurrent infections must be monitored for any signs of viral shedding, especially in the last 4 weeks of pregnancy
–> may need a c section
Herpes
Causative Agent
herpes simplex virus
- contacts genital epithelium
- -> although HSV-1 is virus that infects oral mucosa (cold sores and fever blisters)
- -> HSV-2 is thought of as genital virus
- ——–> in reality either virus can infect either region depending on type of contact
Herpes
Pathogenesis and V Factors
strong tendency to become latent
- -> some type of signal causes most of the HSV genome not to be transcribed in latency
- -> allows virus to be maintained within cells of the NS between episodes
- -> microRNAS are in part responsible for the latency of HSV-1
reactivation of virus can be triggered by stress, UV radiation (sunlight), injury, menstruation, or other microbial infection, etc.
Herpes
Trans and Epi
these viruses are extremely sensitive to the environment
- -> so transmission is primarily through direct exposure to secretions containing the virus
- -> people with active lesions are most significant source of infection
- studies show people with no lesions can still transmit virus due to constant shedding
Herpes Culture and Dx and Px and Tx
sometimes diagnosed based on characteristic lesions alone
- PCR tests available
- alternatively, antibody to either of the viruses can be detected from blood samples
condoms, avoiding sexual contact with infected persons, or possible infected persons, mothers with cold sores should be careful about touching there infants and kissing them
Treatment:
several agents available
-often reduce the rate of shedding
-not curative
-Acyclovir and its derivatives (famciclovir or valacyclovir) are very effective
-topical formulations to be applies to lesions
-pills are also available
Wart Diseases
HPV and molluscum contagiosum
Human Papillomavirus (HPV)
these viruses are the causative agents of genital warts, but an individual can be infected with these viruses without having any warts, while still risking serious consequences
Cause Org: human papillomavirus (nonenveloped, Papovaviridae family, more than 100 types of HPV ie. plantar warts vs cervical cancer)
Trans: Direct contact (STI), also autoinoculation (virus is spread to other parts of the body by touching warts), indirect contact (more common for nongenital HPV)
V Factors: oncogenes (in the case of malignant types of HPV)
Culture/Dx: PCR tests for certain HPV types, clinical diagnosis, Pap smear (first at age 21 or 3 years after first sexual activity)
Px: vaccines available; avoid direct contact; prevent cancer be screening cervix
Tx: warts or precancerous tissue can be removed, virus not treatable
D. Feats: infection may or may not result in warts; infection may result in malignancy
Effect on Fetus: may cause laryngeal warts
S/S: growths on vulva and in/around vagina (females), warts occur in/on penis and scrotum (male)
- in both sexes warts can appear on anus and skin around the groin, such as the area between the thigh and pelvis
- warts range from tiny, flat, not very noticeable bumps, to extensively branching cauliflower-like masses called CONDYLOMA ACUMINATA
- -> these warts are unsightly and can be obstructive but don’t generally lead to more serious symptoms
- -> other HPV infections can infect cervical cells and lead to “silent” abnormal changes and malignancies of the cervix (cervical cancer)
- -> males can also get cancer, most often of the anus or penis, but these cases are less common than cervical caner
- -> mouth and throat cancers can also be caused by HPV infection and are thought to be a consequence of oral sex
Genital wart diseases
Molluscum Contagiosum
Cause Org: Poxvirus, sometimes called the molluscum contagiosum virus (MCV)
Trans: direct contact (STI), also autoinoculation, indirect contact (fomites)
V Factors: —
Culture/Dx: Clinical diagnosis, also histology, PCR
Px: avoid direct contact
Tx: warts can be removed; virus not treatable
D. Feats: wart-like growths are only consequence of infection; can be found on mucous membranes or the skin of the genital area; can take any form of skin lesion
Effect on Fetus: —
Group B Streptococcus
“Colonization” - Neonatal Disease
10-40% of women in the US are colonized asymptomatically, by a beta-hemolytic Streptococcus in Lancefield group B.
- colonization of a pregnant woman is associated with preterm delivery and about half of their infants become colonized during passage through the birth canal or during rupture of membranes and spread of bacteria during that time
- -> so it is considered a repro tract disease
- small number of infected infants experience life-threatening bloodstream infections, meningitis, or pneumonia
- -> if they recover from these acute conditions, they may have permanent disabilities, hearing loss, or impaired vision
in some cases the mother may also experience disease such as amniotic infection or subsequent stillbirths
all pregnant women must be screened at 35-37 weeks
sometimes earlier screening b/c of risk for preterm birth
POSITIVE WOMEN Tx: penicillin or ampicillin, unless the bacterium is found to be resistant to one of them or an allergy (erythromycin may be used)
Trans: vertical
V Factors: —
Culture/Dx: culture of mothers genital tract
Tx: ampicillin, penicillin, or erythromycin *watch for clindamycin-resistant strains
