Infections of the Urogenital Tract and STD's
I. The urogenital tract consists of those organs and glands that are involved in
production, storage and discharge of urine and those organs involved in reproduction. The
organs that are responsible for urine production, storage and discharge are the kidneys,
ureters, urinary bladder and urethra. The male reproductive tract shares the urethra with
the urinary tract. Other male reproductive organs include the testes, vas deferens,
seminal vesicles, penis and bulbourethra. The female reproductive tract is distinct from
the urinary tract and consists of the ovaries, ovarian tubes (fallopian tubes), uterus,
vagina, clitoris, labia minora and labia majora. For the most part, the internal parts of
these tracts are sterile.
A. The flow of urine and mucus through the urinary tract helps to eliminate bacteria
that have invaded. The distal urethra is colonized by several bacterial species in both
the male and female but bacterial numbers are reduced by the washing action of the urine
during urination. The low pH of urine also contributes an antimicrobial affect.
B. The skin of the reproductive organs are colonized by several species of bacteria
including members of the genus Streptococcus, Staphylococcus and Micrococcus. The
skin of the external female genitalia may also be colonized by the yeast Candida
C. The vagina is host to several species of bacteria. In the prepubescent and
post-menopausal female the species of bacteria are similar to those seen on the skin with
some enteric bacteria present. At puberty, hormonal changes lead to increased
polysaccharide levels within the vagina (primarily glycogen). Members of the genus Lactobacillus
come to be the predominant species in the vagina. Metabolism of carbohydrates by Lactobacillus
leads to the production of lactic acid and a subsequent drop in the pH of the vagina
to around 4.5. This significant change leads to the elimination of most bacteria and yeast
from the vaginal mucosa.
II. Symptoms and signs associated with infection of the urinary tract include purulent
discharge from the urethra, pain during urination (dysuria), urge to urinate
(even when little urine is present in the bladder), pain in the lower back, fever and
chills. In the elderly these symptoms may not be present. Most urinary tract infections (UTIs)
begin with infection and inflammation of the urethra (urethritis). If
untreated this infection can ascend into the bladder causing a condition known as cystitis.
The infection can continue to ascend causing infection of the kidneys (pyelonephritis).
It is possible for infection to begin in the kidneys when bacteria are present in the
blood. Though this occurs it is rare. In the male the prostate can become infected (prostatitis).
Several behaviors increase the chances of contracting a UTI, these include not urinating
frequently enough and not fully emptying the bladder when urinating. This retained urine
provides a suitable medium for bacterial growth often containing protein and sugars
removed from circulation by the kidneys. Lack of hydration can lead to insufficient urine
production, this in turn can lead to the development of a UTI. Finally, in females,
improper wiping after urination or defecation can facilitate the transfer of organism from
the anus to the distal urethra.
A. Most urinary tract infections in women are due to the enteric bacteria E. coli.
Endogenous spread of this organism from the perianal region to the distal urethra is
easily accomplished in the female. It was once thought that this type of infection was
solely due to poor personal hygiene. Though proper hygiene plays a role in the development
of UTIs, recent investigations indicate that certain strains of E. coli are
more capable than others at colonizing the urethra. If a women carries one of these
strains she is much more likely to suffer from a UTI than a women who is colonized with a
more benign strain of E. coli.
B. Due to the relatively short length of the female urethra spread of this organism
to the bladder occurs much more easily in the female. Once in the bladder the pathogen can
continue to ascend the urinary tract. Most bladder infections occur in due to such a
C. Urinary tract infections in males are not as frequent due to differences in anatomy
as compared to the female. Furthermore, due to the longer urethra, infection of the distal
urethra does not progress into cystitis as frequently in the male. When a urinary tract
infection does occur in the male, spread to and infection of the accessory sex glands
(prostate, bulbourethra, Cowpers gland, etc.) may occur.
III. Leptospira interrogans is a spirochete that is shed in the
urine of many wild and domestic animals (including cats and dogs). This pathogen causes a
disease known as leptospirosis. L. interrogans are contracted through
the conjunctiva, oral mucosa or abrasions in the skin due to contact with water or soil
contaminated with the urine of an infected animal. Once in the body, it is disseminated to
several organs but causes disease by affecting the liver, kidneys and central nervous
system. Most infections are mild and are limited by the production of antibodies 7-14 days
after infection. Before production of antibodies the patient may demonstrate fever. Some
strains of this bacteria result in liver damage and infection is accompanied by jaundice.
Growth of the organism in the kidney leads to shedding of the bacteria in the urine.
Significant reduction in renal function can occur and is the most common cause of death
associated with leptospirosis.
IV. Streptococcus pyogenes is the etiologic agent of strep throat
and erysipelas. If this condition goes untreated the strong immune response that results
can have a detrimental effect on the kidney. This is due to the presence of
antigen-antibody complexes on the surface of the cells of the glomerulus. The pathogenesis
of this condition is unclear. It may be due to deposition antigen-antibody complexes that
were circulating in the blood. More probably it is due to the presence of proteins on the
surface of certain strains of S. pyogenes that appear similar to those found on the
surface of the cells in the glomerulus of the kidney. Antibodies that will bind these
bacterial proteins will also bind to the glomerular cells. In either case, complement is
activated and leads to destruction of the glomerulus. In most cases, the damaged renal
tissue will heal with no long term reduction in renal function.
V. Coinfection of the vagina with Gardnerella vaginalis and
anaerobic bacteria of the genus Bacteroides results in a condition
known as nonspecific vaginitis. This infection results in a frothy,
fishy-smelling discharge. Transmission to a male during sexual intercourse can lead to the
appearance of lesions on the penis. This condition is known as balantitis.
This infection only occurs if the pH of the vagina rises above 5. Successful treatment of
this condition in the female requires the re-establishment of the normal flora of the
vagina so that the normal pH of the vagina (3.5.- 4.5) can be maintained.
VI. Toxic shock syndrome is a rapidly progressing condition which begins
with muscle aches, head ache and high fever. It can progress to shock and coma quickly
resulting eventually in death. Most cases have been linked to the use of "super"
tampons. When super tampons were first released onto the market, they contained certain
chemicals that restricted the growth of the normal flora of the vagina. This lack of
microbial antagonism allowed S. aureus to proliferate on the mucus membrane or
within the tampon itself. Most women who suffer from this disease often have left the
tampon in for extended periods of time. This appears to allow the toxins produced by S.
aureus to be held in the tampon and slowly absorbed through the mucus membrane. The
toxin known as Toxic Shock Syndrome Toxin 1 (TSST-1) is now known to be a super
antigen. This type of toxin nonspecifically activates helper T cells with the
subsequent release of inflammatory mediators. This results in a systemic loss of vascular
tone and a rapid drop in blood pressure.
VII. In the female, one of the most common urogenital infections is the vulvovaginitis
caused by the yeast Candida albicans. This organism is found as part
of the bodys normal flora. Suppression of the normal flora of the vagina leads to
overgrowth of this yeast in the vagina and on the labia. This condition is referred to as canididiasis.
Many yeast infections occur after the use of a broad spectrum antibiotic. The antibiotic
reduces the Lactobacillus population in the vagina allowing the pH to rise and the
amount of glucose available for Candida growth to increase. Due to the fact that Candida
is not a bacteria, it is not affected by the antimicrobial. Typically this infection is
accompanied by itching and a sweet smelling discharge from the vagina. Diabetics and those
with suppressed immunity are more susceptible to this condition.
IX. With the exception of endogenously acquired urinary tract infections
and yeast infections, the most common pathogens to affect the urogenital tract
are those that are sexually transmitted. Currently there are over 20 known
pathogens that are sexually transmitted and the Center for Disease Control
estimates that 15 million cases of sexually transmitted disease occur
annually. Women carry a disproportionate burden of this epidemic. Many
of these pathogens cause little or no initial pathology in the female so as to
go undetected. Often this leads to spread of the pathogen to other sites in
the reproductive tract where they cause considerable disfunction.
A. Neisseria gonorrhoeae
invades mucus membranes via attachment by the pili.
The resulting inflammatory response results in the ingestion of Neisseria gonorrhoeae
by neutrophils and macrophages. The capsule of these organisms allows them to survive
within the phagocytic cells. Because the bacteria is very susceptible to drying and oxygen
transmission sexual transmission is the most efficient means of transfer.
1. In most cases, Neisseria gonorrhoeae invades the mucus membrane lining the
reproductive tracts of men or women.
a. In males the resulting inflammation is painfully obvious. Furthermore, these
organism are pyogenic and as such pus will often be discharged from the urethra. If
ignored infection can spread into as far as the epididymis. Scarring can block the vas
deferens or spermatic ducts resulting in sterility.
b. In females Neisseria gonorrhoeae colonizes the vagina at or near the cervix.
Pain, inflammation and a bloody discharge may occur. Often no symptoms are noticed and the
infections spreads into the uterus and fallopian tubes resulting in a condition known as salpingitis.
This is one etiologic agent of pelvic inflammatory disease (PID). If
unattended to PID can result in scarring of the fallopian tubes which can render the
female sterile. Neisseria gonorrhoeae can also spread into the blood stream were it
colonizes the joints resulting in inflammation and septic arthritis.
c. Spread of Neisseria gonorrhoeae to the mucus membranes of the pharynx
and rectum can result from oral or anal sex with an infected person. Presence of rectal
gonorrhea in the female is often due to normal spread (due to the proximity of the vagina
2. Infection of the fetus as it passes through an infected vagina can result
colonization of the eyes (gonococcal ophthalmi neonatorum) leading to
blindness. Thus prophylactic administration of antimicrobial eye drops to the eyes occurs
routinely immediately after birth. Since spread of Neisseria gonorrhoeae is almost
solely due to sexual contact children (other than newborns) presenting with Neisseria
gonorrhoeae infections are often reported to child welfare as probable victims of
3. Once the drug of choice for Neisseria gonorrhea was penicillin but due to the
rapid evolution of strains of penicillinase producing Neisseria gonorrhoeae (PPNG),
most cases of this disease are treated with cephalosporins. These antimicrobials act in
much the same way as penicillin but are different enough in chemical structure not to be
degraded by the same enzymes that effect penicillin.
4. In most states extensive measures were put in place during and after World War II to
detect and eliminate gonorrhea. These included widespread distribution of condoms within
the military, use of penicillin and notification of sexual contacts (if known) to identify
and treat those who were infected. These measures drove the rate of gonorrhea to all time
lows in the 1950s. This trend was reversed during the 60s due mainly to
increased the birth control pill ( consequently there was reduced reliance on condoms for
birth control). Increased rates of sexual activity and the nature of the activity
(multiple partners in short periods of time) led to increases in the occurrence of
gonorrhea. During the mid-80s) with increased awareness of HIV, condom use increased
and some surveys indicate that dangerous types of sexual activity decreased. Consequently
decreased levels of Neisseria gonorrhoeae infection have been observed. It is
obvious, but needs to be stated, that patients with Neisseria gonorrhoeae
infections are often practicing those behaviors that lead to numerous other sexually
transmitted diseases. Many of these diseases are more life threatening and less treatable
B. The causative agent of syphilis is a spirochete known as Treponema
pallidum. This organism survives for only a short time outside a human host.
Thus spread of the organism involves intimate contact between an infected person and a
1. Initially infection with Treponema pallidum results in an open sore known as
a chancre. This is referred to as primary syphilis. Though
chancres appear painful, these sores often inflict little or no pain. In the male they are
on the external genitalia and often are immediately noticed. In the female they can be
within the vagina and completely escape notice. The person is infectious due to the
presence of bacteria in the exudate from the sores. These lesions will resolve in a few
weeks. The organism is still present in the blood.
2. Secondary syphilis develops as the organism spreads from the site of
initial infection throughout the body. Multiple eruptions on the skin and mucous membrane,
fever, headache, sore throat and a brownish rash may be observed or reported. Multiple
occurrences of this type of condition is possible. If untreated these reoccurences will
3. Tertiary syphilis develops many years after initial exposure. This
stage involves the development of gummas which are rubbery masses of tissue
that develop on any organ which was infected during the secondary phase of infection.
Though not fatal in themselves, gummas can interfere with normal functioning of the organ.
During this phase neurological involvement may occur. This neurosyphilis can
lead to loss of sight, disruption of motor control, convulsions and mental derangement.
C. Haemophilus ducreyi is the etiologic agent of chancroid. This
organism is spread through sexual contact or by other direct contact between infected
surfaces. Infection results in lesions that resemble a syphilitic chancre. Lesions are
usually found on the genitals. Unlike syphilitic chancres, which are generally painless,
the lesions caused by H. ducreyi are painful. Usually extreme swelling of lymph
nodes in the inguinal area occurs. This can lead to the rupture of these nodes. Though not
common in this country, this disease is endemic in many areas of the world. This infection
seems to be more common in uncircumcised males. In Africa the region in which this
condition is endemic coincides with the region where AIDS is epidemic.
D. Chlamydia are unique bacteria. They have an inner and outer membrane and are
categorized as gram negative organisms. Yet, they do not engage in metabolic activity or
binary fission unless they have invaded a eukaryotic cell. Thus, members of the genus Chlamydia
are all considered obligate intracellular parasites. These organisms lack
the mechanisms to make ATP and thus are unable to survive without a host cell providing
them with energy. They have an unusual dimorphic life cycle and infect through a
metabolically inactive spore-like form. The life cycle of a Chlamydia includes a small,
infectious spore (elementary body) which can survive outside the cell and a
larger, metabolically active cell (reticulate body) which is found only
within a host cell. The infectious elementary body enters macrophages and neutrophils by
way of phagocytosis. They convert into the reticulate body within the phagocytic vacuole
and begin to grow. The action of lysosomes do not destroy the reticulate body. During the
course of growth, more elementary bodies are formed and remain within the vacuole. When
the phagocytic cell dies, these elementary bodies are released and ingested by other
phagocytes thus continuing the lifecycle. Clinically in the United States, chlamydia have
significant impact as the most common sexually transmitted disease agent.
1. Chlamydia trachomatis is transmitted person to person. There
are many subspecies of C. trachomatis which are referred to as serovars.
Minor differences in serovars leads to clinically different infections. Depending on the
serovar this transmission may be from simple contact or via fomites or may require sexual
contact. Three distinct diseases are observed to be caused by members of this species.
Infection of the eye was discussed previously.
a. Certain serovars infect the urogenital tract. Transmission of these organisms relies
upon sexual contact. In most cases infection is asymptomatic. In some individuals this
infection can progress into urethritis, cervicitis PID and salpingitis. It is estimated
that 4 million sexually active individuals become infected annually. Thus if only 10% of
those infected progress from an asymptomatic condition to the more serious forms of
disease significant morbidity will occur.
i. It is known that transmission of Chlamydia transplacentally and to the
neonate during delivery occurs. The significance of this transmission is still under
investigation. It has been determined that expectant mothers who carrying Chlamydia
trachomatis have dramatically increased rates of stillborn infants and infants who
suffer neonatal death.
ii. The neonate who is infected during childbirth may develop a conjunctivitis. The
possibility of this occurring is reduced if antibiotic treatment of the eyes occurs
immediately after birth.
b. Certain sexually transmitted serovars of Chlamydia trachomatis result in a
condition known as lymphogranuloma venereum (LGV). This condition begins
with ulceration of the skin and mucosa of the genital organs. It is carried into the lymph
nodes by the phagocytes. Swelling of the lymph node results in the formation of a bubo.
the node may rupture, drain and then be permanently scarred. Rupture of the lymph node
results in fever and nausea along with localized pain. The rupture lymph node can present
a site of permanent blockage of the lymphatic vessel.
E. Mycoplasma hominis and Ureaplasma urealyticum are mycoplasmas that
colonize the urogenital tract of humans and can exist as part of a persons normal flora
with little or no harm to that person. But in some cases U. urealyticum can causes
a urethritis and lead to sterility or reduced fertility in both the male and female. M.
hominis can cause PID and is implicated in postpartum fever. For the most part it
appears that these organisms are spread by sexual contact.
1. In pregnant women these organisms can result in bigger problems. Ureaplasma
urealyticum and Mycoplasma hominis have been isolated from amniotic
fluid (in the presence of intact fetal membranes) as early as 16-20 weeks gestation. U.
urealyticum can cause a chronic, clinically silent chorioamnionitis and premature
birth. U. urealyticum and M. hominis are a cause of chronic central nervous
system infection in infants. U. urealyticum colonization of the lower respiratory
tract is associated with death and development of chronic lung disease in very low birth
2. Mycoplasmas lack a cell wall. Consequently antimicrobial drugs that interfere with
the synthesis of peptidoglycan have no effect on these organisms. Treatment usually
involves tetracycline, macrolides or aminoglycosides.
F. Herpes simplex virus is the causative agent of several recurrent
ulcerative diseases. Herpes simplex virus Type 1 (HSV-1) usually infects the
mucus membrane of the lips, cheeks, throat or gums. The initial infection results in the
formation of vesicles which usually resolve unnoticed but can rupture and
ulcerate. The virus spreads into the sensory neurons that enervate these regions. The
viral DNA moves through the neurons cytoplasm to the nucleus which is located in the
trigeminal ganglia. It establishes a latent infection within these neurons.
The viral particles can be shed from these neurons at any time after the establishment of
latency. Usually this shedding is follows periods of physical or emotion stress. The newly
shed particles are released in the same area as the initial viral infection. They result
in lesions that rapidly ulcerate. During this period the person is highly infectious. Herpes
simplex virus Type 2 (HSV-2) is most commonly associated with genital herpes.
It causes ulcerative lesions on the skin of the penis and surrounding regions. In the
female the lesions can be on the labia majora or minora or on the mucus membrane of the
vagina. Lesions in the vagina may not be accompanied by significant discomfort and may go
unnoticed by the women.
1. HSV-1 can be initially infect mucus membranes surrounding the eye (conjunctiva) and
thus be maintained in sensory nerves of the eye. Repeated episodes of HSV release can lead
to the scarring of the cornea and the loss of vision. This is referred to as herpatic
2. Transmission of HSV-1 usually occurs by fomites (shared eating utensils,
drinking out of the same glass, etc.) or direct oral contact like kissing. It is a fairly
widespread virus in the general public and causes little mortality. Transmission of HSV 2
usually is by sexual contact. Because the lesions in the male are often near the base of
the penis condoms may not be effective in limiting the spread of infectious fluids during
sexual intercourse. It should also be noted that HSV-2 can be transmitted to the mouth
during oral sex.
3. Diagnosis is usually made examination of lesions and history of recurrence. Virus
can be easily grown in cell culture and the subtype identified by monoclonal
4. Duration of the secondary lesion of both HSV-1 and -2 can be significantly reduced
by the use of nucleotide analog drugs. One of the most commonly used is acyclovir.
G. Hepatitis refers to any condition in which the liver becomes
inflamed. This may be the result of toxic ingestion, bacterial infection or other less
well defined etiologies. Viral hepatitis results from the invasion of liver
cells by viruses and the resulting cytopathology. Currently several viruses are known to
infect the liver causing viral hepatitis. They are referred to as hepatitis A,
hepatitis B, hepatitis C, hepatitis D (delta agent),
hepatitis E and hepatitis G. There are probably several other
viral agents that are currently circulating that have yet to be isolated and
characterized. To date, Hepatitis B and D have been shown to be effectively transmitted
via sexual contact. Sexual transmission of Hepatitis C virus is matter of some debate with
most evidence indicating that transmission via this route is relatively rare if it occurs
1. Hepatitis B virus (HBV) results in a condition referred to as serum
hepatitis. The virus is a enveloped DNA virus. Initial infection leads to severe
liver destruction and thus jaundice. Fever and malaise are also common. 5-10% of those
infected will become chronically shedders of the virus. The virus is shed into the blood
stream and can be found in proteinaceous secretions such as semen. In this country
venereal transmission is the most significant route of infection. Transmission can also
occur via contaminated blood products and sharing of needles in IV drug use.
a. The chronic shedder releases large amounts of viral protein that make up the outer
capsid of the virion (HBsAg). Most of these proteins form a structure that
lacks any viral DNA and thus are not infectious. They arrange themselves into small balls
or worm-like filaments.
b. Mortality is around 1/100 infected. It is becoming apparent though that persistent
infection leads to cirrhosis and probably plays a role in the development of liver cancer.
This long term morbidity will reduce the life span of the chronically infected individual
c. In this country, those measures that reduce the spread of other venereal diseases
will serve to reduce the spread of HBV. The development of a safe vaccine has allowed the
protection of those exposed to blood and other body fluids. This vaccine is one of the
first widely used genetically engineered vaccines.
2. Hepatitis D virus (delta agent; HDV) is a defective virus in that it
can not make viral particles without the surface protein of HBV (HBsAg). This virus
coinfects cells already harboring Hepatitis B virus. When a person chronically infected
with HBV is exposed to the delta agent it may cause the hepatitis to reactive and worsen.
Coinfection often results in rapid degeneration of the liver and increased morbidity.
3. Human Papilloma viruses (HPV) are the viruses that are responsible for common skin
warts and certain strains of HPV are responsible for genital
warts (condylomata acuminata).
HPV is usually transmitted by direct contact including sexual contact. The appearance of the warts
may take from l to 20 months from the time of exposure but usually become
apparent within 4 months. There are over 100 viruses known in the HPV family
of viruses. Every year, about 5.5 million Americans are newly infected with
genital HPVs — 20 million women and men are now infected.
a. Genital warts are often
first noticed as a firm painless tissue on the vulva, penis or area around
the rectum. These warts are flesh-colored, lumps which may be single or in
groups. They may look like a tiny cauliflower or be flat. HPV can cause
warts in the around the mouth due to sexual transmission during oral sex.
b. There is no easy way to
tell if someone is infected with an HPV. Asymptomatically infected
individuals are capable of HPV transmission. Though condoms do reduce the
risk of infection by reducing the amount of direct contact between the
genitals during sex, condoms do not entirely eliminate such contact and
thus do not totally prevent transmission of HPV.
c. Certain types of HPV
can cause abnormal cell growth known as dysplasia.
Dysplasia can develop into several kinds of cancer. These include cancers
of the penis and anus, and cervical cancer in women. Some types of
HPV are referred to as "low-risk" viruses because they rarely
develop into cancer; these include HPV-6 and HPV-11. HPV viruses that can
lead to the development of cancer are referred to as
"cancer-associated types." Sexually-transmitted,
cancer-associated HPV have been linked with cancer in both men and women;
most importantly they include HPV-16, HPV-18, HPV-31, and HPV-45. These
cancer-associated types of HPV cause growths that usually appear flat and
are nearly invisible, as compared with the warts caused by HPV-6 and
i. Dysplasia can be detected
by Pap smears. They are usually used to check a woman's cervix, but can
also be used to check the anus in men and women. A swab is rubbed on the
area being checked. The swab picks up some cells, which are smeared on a
glass slide and examined under a microscope. If the Pap smear results
are not clear, an HPV test can indicate who needs treatment.
ii. If left untreated,
genital warts may go away on their own, stay the same or continue to
grow. However, most health care providers recommend that they be
treated. Warts can be burned off with chemicals, electric current, laser
therapy, surgically removed or frozen off. Even after treatment, warts
can recur. Sexual contacts need to be identified and similar treated. In
some cases, the body will develop an immunity to the particular strain
of HPV and eliminates it. However, this immunity may not extend to other
strains of HPV
Here are some links!!
Here are two pages hosted by Cornell University Medical Center that give
in-depth analysis of pathology affecting the Urogenital tract.
GALL BLADDER, & PANCREAS
Textbook of Microbiology Microbiology of the Genitourinary System
Social Health Association Introduction to STD's