microbiology chapter 21

female

Normal Biota of the ____________ Genital Tract: - Only the vagina harbors a normal population of microbes. - Lactobacillus species thrive in the acidic environment and contribute to it by converting sugars to acid. - Candida albicans is also present at low levels. - Same biota as urethra outside of childbearing years

urinary tract

• Defenses of the ______ ______: - 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.

neurosyphilis

Can involve any part of the nervous system - Diverse results include severe headaches, atrophy of the optic nerve, blindness, and dementia

Human Papillomavirus Infection (HPV)

Causative Agent: - Human papillomaviruses: - Nonenveloped DNA viruses belonging to the Papovaviridae family - Over 100 different types of HPV • Signs and Symptoms: - Warts: - Outgrowths of tissue on the genitals - In females: occur on the vulva and in and around the vagina - In males: can occur in or on the penis and the scrotum - In both sexes, warts can appear on the anus and the skin around the groin. - Appearance of warts: - Tiny, flat, inconspicuous bumps - Condyloma acuminata: extensively branching, cauliflowerlike masses - Can be unsightly and obstructive, but don't generally lead to more serious symptoms - Certain types of viruses are oncogenic. - Cervical, penal, rectal, oral and throat cancers • Transmission and Epidemiology: - Young women have the highest rate of HPV infections: - 25 - 46% of women under the age of 25 are infected with genital HPV - Mode of transmission is direct contact • Treatment: - Infection with HPV is incurable. - Genital warts can be removed through a variety of methods - Possible for the virus to resolve itself, but this is very unpredictable. • Prevention: - Avoid direct, unprotected contact. - Gardasil vaccine prevents infection by four types of HPV - Pap smear: - Standardized screen for cervical cell changes - Development process can be stopped by removal of the affected tissue.

gonorrhea

Causative Agent: - Neisseria gonorrhoeae: - Gram-negative diplococcus • Signs and Symptoms: - Male - Urethritis - Painful urination - Yellowish discharge - 10% of cases are asymptomatic - Can occasionally spread from the urethra to the prostate gland and the epididymis causing infertility - Rare complications of gonococcal bacteremia are arthritis, meningitis and endocarditis. - Female - Mucopurulent (containing mucus and pus) or bloody vaginal discharge occurs in about half the cases (50% cases are asymptomatic). - Painful urination if the urethra is affected. - Major complications occur when the infection ascends to higher reproductive structures causing salpingitis and/or pelvic inflammatory disease. - 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 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. • Pathogenesis and Virulence Factors: - Fimbrial genes can rearrange themselves to put out fimbriae of different configurations: - This antigenic variation confuses the body's immune system. - Antibodies that previously recognized fimbrial proteins may not recognize them once they are rearranged. - IgA protease: - Cleaves IgA molecules stationed on mucosal surfaces - "Blebs" of outer membrane containing endotoxin are shed, causing localized damage. • Transmission and Epidemiology: - Except for neonatal infections, the gonococcus is spread through some form of sexual contact. • Culture and Diagnosis: - Males: gram stain of urethral discharge is diagnostic - Females: antibody and antigen tests available • Prevention: - No vaccine is yet available for gonorrhea: - Avoid mucosal contact with infected people. • Treatment: - Gonococcal Isolate Surveillance Project (GISP) run by the CDC: - Monitors the occurrence of antibiotic resistance in N. gonorrhoeae

candida albicans

Characteristics: - Dimorphic fungus - Normal biota in 50 - 100% 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. • Transmission and Epidemiology: - Vaginal infections are nearly always opportunistic - Possible to transmit yeast through sexual contact: - Recipient's immune system may subdue the yeast so that it acts as normal biota to them. • Prevention and Treatment: - No vaccine is available - Topical and oral azole drugs are used to treat vaginal candidiasis, many available over the counter

urine

Defenses in the __________: - Acidic pH - Lysozyme - Lactoferrin: iron-binding protein - Secretory IgA

normal biota

In both genders, the outer region of the urethra harbors some _______ _______: - Kidneys, ureters, bladder, and upper urethra are presumably kept sterile by urine flow and regular bladder emptying.

vaginitis

Inflammation of the vagina - Characterized by some degree of vaginal itching, depending on the etiologic agent - Symptoms may include burning and discharge, which may take different forms as well Vaginosis: - Similar to vaginitis, but does not include significant inflammation • Causative Agents: - Can be caused by a variety of bacteria and even protozoa

male

Innate defenses of the _______ reproductive system: - Flushing action of the urine, which helps move microorganisms out of the system

female

Innate defenses of the __________ reproductive tract: - Mucus membranes and the protective covering of secreted mucus - Secretory IgA antibodies specific for any previously encountered infections - Vaginal pH of about 4.5 during childbearing years

syphilis

Marked by clinical stages designated as: - Primary syphilis - Secondary syphilis - Tertiary syphilis • 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

gummas

Painful, swollen, syphilitic tumors

urethra

Principal known residents of the ______: - Nonhemolytic streptococci - Staphylococci - Corynebacteria - Lactobacilli

urinary tract infection (UTI)

Signs and Symptoms: - Cystitis is a disease of sudden onset: - Pain - Frequent urges to urinate, even when the bladder is empty - Dysuria: burning pain accompanying urination - Pyuria: cloudy urine due the presence of bacteria and white blood cells - Hematuria: presence of blood in the urine causes it to have an orange color - Low-grade fever and nausea - Signs and symptoms of pyelonephritis (kidney infection): - Back pain - High fever - A serious infection that can result in permanent damage to the kidneys if improperly or inadequately treated • Causative Agents: - 95% of UTIs are caused by normal biota of the gastrointestinal tract: - Escherichia coli is responsible for 80% of these. - Staphylococcus saprophyticus and Enterococcus are common culprits. - Many women experience "recurrent urinary tract infections": - Some E. coli can invade the deeper tissue of the urinary tract and avoid being killed by antibiotics. • Treatment: - Sulfa drugs such as trimethoprim-sulfamethoxazole are used for UTIs of various etiologies. - Non-antibiotic drug phenazopyridine (Pyridium) is administered simultaneously: - Relieves the uncomfortable symptoms of burning and urgency - Azo dye that turns the urine dark red or dark orange - A large percentage of E. coli strains are resistant to penicillin: - E. coli ST131 is highly virulent and resistant to multiple antibiotics.

genital herpes

Signs and Symptoms: - Multiple presentations: - After initial infection, a person may notice no symptoms - Could also cause the appearance of a single or multiple vesicles on the genitalia, perineum, thigh, and buttocks - Vesicles are small and filled with clear fluid. - Intensely painful to the touch - Appearance of lesions may be accompanied by: - Malaise - Anorexia - Fever - Bilateral swelling and tenderness in the groin - After initial recovery from infection: - May have recurrent episodes of lesions - Generally less severe than the original symptoms - Some people never have recurrent lesions. - Some people have nearly constant outbreaks with little recovery time between them. - Average recurrences is four to five a year. - Every year, one or two persons per million with chronic herpes infections develop encephalitis • Causative Agent: - Both HSV-1 and HSV-2 can cause genital herpes if the virus contacts the genital epithelium • Pathogenesis and Virulence Factors: - Herpesviruses have the tendency to become latent: - Molecular basis of latency is not entirely clear. - Reactivation can be triggered by a variety of stimuli • Transmission and Epidemiology: - Transmission is primarily through direct exposure to secretions containing the virus: - People with active lesions are the most significant source of infection. - Genital herpes can be spread even when no lesions are present. - Estimated that 20% of American adults have genital herpes • Culture and Diagnosis: - HSV-1 and HSV-2 can sometimes be diagnosed based on the characteristic lesions alone. - Antibody and antigen to either virus can be detected from blood samples or lesions: - Detecting antibody does not necessarily indicate whether the infection is oral or genital or whether the infection is new or preexisting. - Herpes-infected cells may be noticed by Pap smear. • Prevention and Treatment: - No vaccine is currently available for HSV - Avoiding contact with infected body surfaces - Acyclovirs are effective but not curative

Trichomonas vaginalis

Small, pear-shaped protozoa with four anterior flagella and an undulating membrane: - Has no cyst form, and 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.

chlamydia

The most common reportable infectious disease in the US: - More than 1 million cases reported annually - Actual infection rate may be 5 - 7 times that number - Prevalence among sexually active young women ages 14 - 19: 6.8% - At least 2 - 3 times as common as gonorrhea - Vast majority of cases are asymptomatic • Signs and Symptoms: - 75% of cases are asymptomatic - Males: - Discharge and painful urination - Untreated infections may lead to epididymitis. - Females: - Cervicitis - Discharge - Salpingitis - PID - 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 become inflamed and tender, causing swelling of genitalia or anus. - Babies born to mothers with Chlamydia infections can develop eye infections and pneumonia if they become infected during passage through the birth canal: - Antibiotic drops or ointment applied to newborn's eyes are chosen to eliminate both Chlamydia and N. gonorrhoeae. • Pathogenesis and Virulence Factors: - Chlamydia is able to grow intracellularly and avoid the host's immune response: - Unique cell wall prevents the phagosome from fusing with the lysosome inside phagocytes. - Presence of bacteria inside cells causes the release of cytokines that provoke intense inflammation. - The defensive inflammatory response leads to most of the actual tissue damage in Chlamydia infections. - Repair of inflammation leads to scarring, which can severely damage the fallopian tube. • Culture and Diagnosis: - Usually determined by detection of antibody or antigen: - A urine test is available, but is less accurate for females than males. • Prevention: - Avoiding contact with infected and secretions. • Treatment: - CDC recommends annual screening of young women for the presence of the bacterium. - Doxycycline or azithromycin

genital ulcer disease

Three common infectious conditions can result in lesions on the genitals: - Syphilis - Chancroid (we won't cover) - Genital herpes • Infection with an ulcer disease increases the chances of infection with HIV because of open lesions.

Gardnerella

Vaginosis: - Common condition in women in their childbearing years - Doesn't appear to induce inflammation in the vagina - Also known as bacterial vaginosis (BV) - A vaginal discharge with a very fishy odor • Pathogenesis and Virulence Factors: - Mechanism of damage is not well understood. - Can lead to PID, infertility, and ectopic pregnancies - Babies born to mothers with vaginosis have low birth weights. • Transmission and Epidemiology: - Not considered to be sexually transmitted - We do not know what exactly causes increased numbers of___________________. - Low pH typical of the vagina is higher in vaginosis. • Culture and Diagnosis: - Simple stain of vaginal secretions is used to examine "clue cells" • Prevention and Treatment: - Metronidazole or clindamycin

latency tertiary

_______ or _______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. • 30% of infections enter a highly varied latent period that can last 20 years or longer

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.

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 - 6 weeks. - At this point the spirochete has escaped into circulation and is entering a period of tremendous activity.

cardiovascular

____________ syphilis: - The aorta is subject to distention and fatal rupture. - Aortic valves can also be damaged, resulting in insufficiency and heart failure.

congenital

syphilis: • The syphilis 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 • Causative Agent: - Treponema pallidum: - Gram-negative spirochete • Pathogenesis and Virulence Factors: - Binds to the epithelium of mucus membranes by its hooked tip - Produces no toxins and does not kill cells directly - Although phagocytes act against it and antitreponemal antibodies are formed, immune responses are unable to contain it. • Transmission and Epidemiology: - Humans are the sole natural hosts and source of T. pallidum. - Rates have been increasing in the U.S. since 2003. - Continues to be a serious problem worldwide, especially in Africa and Asia: - Persons with syphilis often suffer coinfections with other STIs, especially HIV. • Culture and Diagnosis: - Can be detected in patients most rapidly by using dark-field microscopy of a suspected lesion - Blood tests based on antibody detection are used for diagnosis • Prevention and Treatment: - Barrier protection provides protection during the primary phase. - No vaccine currently exists. - Treat with single long lasting injection of Penicillin G