Micro Chapter 21

Gonorrhea causative agent

Neisseria gonorrhoeae: Gram-negative diplococcus Appears as kidney bean-shaped bacteria with their flat sides touching

Escherichia coli is responsible for 80% of these UTIs

Normal biota in the GI tract, not the ones that cause diarrhea or other digestive tract diseases Staphylococcus saprophyticus and members of the Enterobacteriaceae family (Klebsiella pneumoniae, Proteus mirablis) are common culprits

Normal Biota of the Female Genital Tract

Occasional "trespassers" or possibly permanent residents of the upper female reproductive tract Before puberty and after menopause, the pH is close to neutral and the vagina harbors the same biota as the urethra After the onset of puberty, estrogen leads to glycogen release in the vagina, resulting in an acidic pH

microbial composition

varies between men and women, and among individuals

Latency and Tertiary Syphilis

30% of infections enter a highly varied latent period that can last 20 years or longer: Antibodies to the bacterium are readily detected, but the bacterium is not This final stage of syphilis is relatively rare today because of widespread use of antibiotics By the time a patient reaches this stage, numerous pathologic complications occur in susceptible tissues and organs

normal biota of the gastrointestinal tract:

95% of UTIs are caused by

defenses in the urine

Acidic pH Lysozyme: enzyme that breaks down peptidoglycan Lactoferrin: iron-binding protein that inhibits bacterial growth Secretory IgA: specific for previously encountered microorganisms

Secondary syphilis

Appears about 3 weeks to 6 months after the chancre heals: Many systems of the body have been invaded Symptoms are more profuse and intense Initial symptoms are: Fever Headache Sore throat Lymphadenopathy Peculiar red or brown rash that breaks out on all skin surfaces Lesions contain viable spirochetes Major complications linger for months and years

pyelonephritis

Back pain and high fever A serious infection that can result in permanent damage to the kidneys if improperly or inadequately treated

Normal biota are the most common microbial threat to the urinary tract:

Cells of the lining of the urinary tract have different chemicals on their surface than those lining the GI tract Bacteria that are adapted to adhere to the chemical structures in the GI tract cannot attach to the urinary epithelium

chlamydia

Certain strains of C. trachomatis can invade lymphatic tissues, resulting in lymphogranuloma venereum: Condition accompanied by headache, fever, and muscle aches Lymph nodes near the lesion begin to fill with granuloma cells and become enlarged and tender "Nodes" cause long-term lymphatic obstruction that leads to chronic, deforming edema of genitalia or anus Disease endemic in South America, Asia, and Africa, but can occur in other parts of the world Incidence in U.S. is about 500 cases per year

Candida albicans

Characteristics: Dimorphic fungus Normal biota in the majority of humans Live in low numbers on mucosal surfaces of the mouth, gastrointestinal tract, vagina, etc. Vulvovaginal candidiasis: Yeast is easily detectable in a wet prep or a Gram stain of material obtained during a pelvic exam Presence of pseudohyphae in the smear is a clear indication of the yeast growing rapidly and causing infection

trichomonas vaginalis

Chronic infection can make a person more susceptible to other infections, including HIV: May also lead to infertility Women who have become infected during pregnancy are predisposed to premature labor and low-birth-weight infants Easily transmitted through sexual contact since it is common biota in many people Does not appear to undergo opportunistic shifts within hosts: Does not become symptomatic under certain conditions Causes symptoms when transmitted to a noncarrier

flora of the penis

Colonized by aerobic Pseudomonas and Staphylococcus species In an uncircumcised penis, the area under the foreskin is colonized by anaerobic gram-negatives

Urinary Tract (Both Sexes)

DEFENSES: 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 NORMAL BIOTA: Nonhemolytic Streptococcus, Staphylococcus, Corynebacterium, Lactobacillus, Prevotella, Veillonella, Gardnerella

Primary syphilis

Early indication of syphilis is the appearance of a hard chancre at the site of entry of the pathogen: These ulcers tend to be painless and may escape notice, especially on internal surfaces Chancre heals spontaneously without scarring in 3 to 6 weeks At this point, the spirochete has escaped into circulation and is entering a period of tremendous activity

defenses of the urinary tract

Flushing action of urine flowing out of the system Urine flow also encourages desquamation of epithelial cells lining the urinary tract, shedding microbes with the cells

discharge diseases

Infectious agent causes an increase in fluid in the male and female reproductive tract Causative agents are transferred to new hosts when the fluids in which they live contact the mucosal surfaces of the receiving partner Trichomoniasis Gonorrhea Chlamydia

Urinary system harbors a diverse microbiota:

Lower urethra has a well-established microbiota, while the upper urinary tract appears to have fewer types and lower abundance

chlamydia

Males: Causes inflammation of the urethra Symptoms mimic gonorrhea: discharge and painful urination Untreated infections may lead to epididymitis Females: Cervicitis Discharge Salpingitis

Syphilis: Treponema pallidum

Marked by clinical stages designated as: Primary Secondary Tertiary Also has latent periods of varying duration during which it is quiescent Spirochete appears in the lesions and blood cultures during the primary and secondary stages, and is transmissible at these times: Also transmissible during the early latency period between secondary and tertiary syphilis Largely nontransmissible during the "late latent" and tertiary stages

Catheter-associated UTIs (CA-UTIs):

National Healthcare Safety Network recommends minimizing the use of ___ to limit incidence of these infections

chlamydia

PID is a frequent sequela of female chlamydial infection: More likely to experience PID as a result of Chlamydia than gonorrhea 75% of Chlamydia infections are asymptomatic, which puts women at risk for developing PID because they do not seek treatment for the initial infection PID itself may be acute and painful, or asymptomatic, allowing damage to the upper reproductive tract to continue unchecked

gummas

Painful, swollen, syphilitic tumors Develop in tissues in the liver, skin, bone, and cartilage Usually benign and only occasionally lead to death, but can impair function

gonorrhea

Pelvic inflammatory disease (PID): salpingitis that includes inflammation of other parts of the upper reproductive tract Not unusual for the microbe that causes PID to become involved in mixed infections with anaerobic bacteria Buildup of scar tissue from PID can block fallopian tubes, causing sterility or ectopic pregnancies

cardiovascular syphillis

Results from damage to the small arteries in the aortic cell wall As the fibers in the wall weaken, the aorta is subject to distention and fatal rupture Aortic valves can also be damaged, resulting in heart failure

cystitis

Same as for urinary tract Urethra: same as for urinary tract Outer surface of penis: Pseudomonas and Staphylococcus Sulcus of uncircumcised penis: anaerobic gram-negatives

gonorrhea

Serious consequences can occur outside of the reproductive tract: In a 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 painful, sporadic, papular rash on the limbs Rare complications of gonococcal bacteremia are meningitis and endocarditis Children born to gonococcus carriers are in danger of being infected: Physicians screen pregnant mothers for its presence Gonococcal eye infections are very serious and result in keratitis, ophthalmia neonatorum, and blindness Antibiotic eye drops or ointments are applied at birth as a universal precaution Finding gonorrhea in children other than neonates is strong. evidence for sexual abuse by adults

gonorrhea

Signs and symptoms in the male: Urethritis Painful urination Yellowish discharge Relatively large number of cases are asymptomatic In most cases, infection is limited to the distal urogenital tract Can occasionally spread from the urethra to the prostate gland and the epididymis Scar tissue formed in the spermatic ducts during the healing of an invasive infection can render a man infertile

Trichomonas vaginalis

Small, pear-shaped protozoa with four anterior flagella and an undulating membrane: Has no cyst form Does not survive long out of the host Causes asymptomatic infections in approximately 50% of females and males: Considered asymptomatic infectious agents rather than normal biota Some people experience long-term negative effects Males seldom have symptoms Females have a white to green frothy discharge

uti infection treatment

Sulfa drugs such as trimethoprim-sulfamethoxazole are used for UTIs of various etiologies Nonantibiotic drug phenazopyridine (Pyridium) is administered simultaneously: Relieves the uncomfortable symptoms of burning and urgency Should only be administered for two days Azo dye that turns the urine to a dark orange to red color A large percentage of E. coli strains are resistant to penicillin derivatives

Congenital syphilis

The bacterium can pass from a pregnant woman's circulation into the placenta and be carried throughout the fetal tissues: Infection leading to congenital syphilis can occur at any of the three trimesters Inhibits fetal growth and disrupts critical periods of development Can result in mild defects to spontaneous miscarriage or stillbirth Infants often demonstrate such signs as profuse nasal discharge, skin eruptions, bone deformation, and nervous system abnormalities The late form gives rise to an unusual assortment of problems in the bones, eyes, inner ear, and joints, and causes the formation of Hutchinson's teeth

chlamydia

The infectious stage is the elementary body, which is taken into a phagocyte and ends up in its phagosome In the phagosome, each elementary body develops into a reticulate body Reticulate bodies multiply by binary fission Mature reticulate bodies become reorganized into elementary bodies Completed elementary bodies are released from the host cell

Chlamydia

The most common reportable infectious disease in the U.S.: More than 1 million cases reported annually Actual infection rate may be 5 to 7 times that number Prevalence among sexually active young women ages 14 to 19: 6.8% Vast majority of cases are asymptomatic Causative agent: C. trachomatis is a very small gram-negative bacterium Lives inside host cells as an obligate intracellular parasite All Chlamydia species alternate between two distinct stages

Innate defenses of the female reproductive tract vary over a woman's lifetime:

Vagina is lined with mucous membranes and has the protective covering of secreted mucus: Mucus is a major nonspecific defense during childhood and menopause Secretory IgA antibodies specific for any previously encountered infections

genital system

also known as the reproductive system, functions mainly in reproduction

Female Genital Tract (Childbearing Years)

defenses: Acidic pH, mucus secretions, secretory IgA normal biota: Variable, but often Lactobacillus predominates; also Prevotella, Sneathia, Streptococcus, and Candida albicans

Female Genital Tract (Childhood and Postmenopause)

defenses: Mucus secretions, secretory IgA normal biota: Same as for urinary tract

male genital tract

defenses: Same as for urinary tract normal biota: Urethra: same as for urinary tract Outer surface of penis: Pseudomonas and Staphylococcus Sulcus of uncircumcised penis: anaerobic gram-negatives

Candida albicans

is also present at low levels: Overgrowth may result in a symptomatic yeast infection

female urethra

is short (3.5 cm long) and in close proximity to the anus: Can act as a pipeline for bacteria from the GI tract to the bladder, resulting in urinary tract infections

Acute uncomplicated UTI:

only the bladder is involved in infection

urinary tract

removes substances from the blood, regulating certain body processes, and forming urine and transporting it out of the body

lactobacillus

species thrive in the acidic environment and contribute to it by converting sugars to acid combined with the acidic environment, discourages the growth of many microorganisms