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