Reproductive: Microbiology STI
80 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a common factor contributing to the high rates of STIs each year?

  • Access to healthcare facilities
  • High vaccination rates
  • Widespread screening programs
  • Lack of education on prevention (correct)

    • What is the relationship between multiple STIs and HIV transmission?

  • One STI can increase the risk of HIV transmission (correct)
  • Only certain STIs affect HIV transmission rates
  • Multiple STIs have no impact on HIV transmission
  • Multiple STIs decrease the risk of HIV transmission

    • Which organism is NOT associated with cervicitis or urethritis?

  • T.vaginalis (correct)
  • M.genitalium
  • C.trachomatis
  • N.gonorrhoea

    • What condition is caused by the disruption of vaginal flora?

    <p>Vaginosis</p> Signup and view all the answers

    Which organism is primarily associated with genital ulcers?

    <p>H.ducreyi</p> Signup and view all the answers

    What is the causative agent of trichomoniasis?

    <p>Trichomonas vaginalis</p> Signup and view all the answers

    Which symptom is most commonly associated with Candida albicans infections?

    <p>Cheesy discharge</p> Signup and view all the answers

    What is a typical treatment for trichomoniasis?

    <p>Metronidazole</p> Signup and view all the answers

    Which of the following is a predisposing factor for Candida albicans overgrowth?

    <p>Hormonal changes</p> Signup and view all the answers

    What diagnostic method is used for Trichomonas vaginalis?

    <p>PCR on first pass urine</p> Signup and view all the answers

    What is the estimated annual number of cancer deaths caused by human papillomavirus (HPV)?

    <p>250,000</p> Signup and view all the answers

    How many types of human papillomavirus (HPV) are known to infect the genital tract?

    <p>40</p> Signup and view all the answers

    Which types of HPV are responsible for the majority of cervical cancer cases?

    <p>HPV-16 and 18</p> Signup and view all the answers

    What is the main mechanism by which HPV causes warts?

    <p>Disruption of p53 and Rb proteins</p> Signup and view all the answers

    What preventive measure is recommended to help protect against HPV-related cancers?

    <p>Nonavalent vaccine</p> Signup and view all the answers

    Which bodily fluids can transmit the human immunodeficiency virus (HIV)?

    <p>All bodily fluids</p> Signup and view all the answers

    What characterizes the initial acute phase of HIV infection?

    <p>Massive loss of CD4 T cells</p> Signup and view all the answers

    Which cells are primarily targeted by HIV in the body?

    <p>CD4+ cells</p> Signup and view all the answers

    What factor increases the likelihood of HIV transmission?

    <p>Presence of other STIs</p> Signup and view all the answers

    Which is an important step in diagnosing HPV?

    <p>Papanicolaou (Pap) smear test</p> Signup and view all the answers

    Which organism is primarily responsible for Gonorrhoea?

    <p>Neisseria gonorrhoea</p> Signup and view all the answers

    What is a common complication of untreated Gonorrhoea in females?

    <p>Pelvic inflammatory disease</p> Signup and view all the answers

    What mode of transmission is primarily associated with Syphilis?

    <p>Sexual contact</p> Signup and view all the answers

    Which test is most commonly used for diagnosing Gonorrhoea?

    <p>PCR</p> Signup and view all the answers

    What symptom is typically NOT associated with Gonorrhoea in females?

    <p>Painless ulcer</p> Signup and view all the answers

    What is the first stage of untreated Syphilis characterized by?

    <p>A painless primary chancre</p> Signup and view all the answers

    Which antibiotics are used to treat Gonorrhoea?

    <p>IM ceftriaxone with azithromycin</p> Signup and view all the answers

    Which symptom occurs in the secondary stage of Syphilis?

    <p>Skin rash</p> Signup and view all the answers

    Which method has the highest specificity for diagnosing Syphilis?

    <p>Treponemal tests</p> Signup and view all the answers

    How does Neisseria gonorrhoea typically enter the human body?

    <p>Through vaginal or urethral mucosa</p> Signup and view all the answers

    What is the primary type of Herpes Simplex Virus responsible for most genital herpes infections?

    <p>HSV-2</p> Signup and view all the answers

    Which treatment option is NOT recommended for herpes simplex lesions?

    <p>Topical antiviral creams</p> Signup and view all the answers

    What is the gold standard for diagnosing Herpes Simplex Virus infections?

    <p>PCR testing</p> Signup and view all the answers

    What is the main complication of chlamydia in females?

    <p>Ectopic pregnancy</p> Signup and view all the answers

    What is the typical symptom observed after a Chlamydia infection?

    <p>Watery or mucopurulent discharge</p> Signup and view all the answers

    Which of the following is a standard treatment for Chlamydia trachomatis?

    <p>Azithromycin</p> Signup and view all the answers

    What percentage of herpes infections may be asymptomatic?

    <p>75%</p> Signup and view all the answers

    How is Chlamydia primarily transmitted?

    <p>Sexual contact</p> Signup and view all the answers

    What are common symptoms of genital herpes?

    <p>Painful blisters and ulcers</p> Signup and view all the answers

    Which type of bacterial STI can cause trachoma?

    <p>Chlamydia trachomatis</p> Signup and view all the answers

    What is a significant contributing factor to the high rates of STI infections each year?

    <p>Taboo surrounding testing and diagnosis</p> Signup and view all the answers

    Which statement accurately describes the transmission of STIs?

    <p>Close contact and direct transmission of body fluids are necessary for transmission.</p> Signup and view all the answers

    What effect can one STI infection have on the risk of acquiring another STI?

    <p>It increases the likelihood of acquiring another STI.</p> Signup and view all the answers

    Which organism is commonly associated with causing pelvic inflammatory disease?

    <p>C.trachomatis</p> Signup and view all the answers

    What symptom is associated with vaginosis due to the disruption of vaginal flora?

    <p>Unpleasant odor or vaginal discharge</p> Signup and view all the answers

    What is a common symptom of trichomoniasis in women?

    <p>Malodorous frothy vaginal discharge</p> Signup and view all the answers

    Which of the following factors increases the risk of Candida albicans overgrowth?

    <p>Hormonal changes</p> Signup and view all the answers

    What is the primary method for diagnosing Trichomonas vaginalis?

    <p>High vaginal swab or PCR on urine</p> Signup and view all the answers

    Which treatment is commonly used for vaginal candidiasis caused by Candida albicans?

    <p>Fluconazole</p> Signup and view all the answers

    Which of the following is true regarding Trichomonas vaginalis?

    <p>It causes an estimated 143 million infections annually.</p> Signup and view all the answers

    What percentage of females are expected to acquire a genital HPV infection by the age of 50?

    <p>80%</p> Signup and view all the answers

    What is the incubation period for HPV infections?

    <p>1-6 months</p> Signup and view all the answers

    Which HPV types are most commonly associated with cervical cancer?

    <p>HPV-16 and 18</p> Signup and view all the answers

    What is the role of the viral proteins E6 and E7 in HPV infections?

    <p>They promote cell overgrowth by disrupting p53 and Rb.</p> Signup and view all the answers

    What is the primary purpose of a Papanicolaou (Pap) smear test in detecting HPV?

    <p>To detect early epithelial changes.</p> Signup and view all the answers

    Which treatment option is most commonly used for managing HPV-related warts?

    <p>Liquid nitrogen</p> Signup and view all the answers

    What is a significant risk factor that increases HIV transmission?

    <p>Presence of other STIs</p> Signup and view all the answers

    What characterizes the chronic phase of HIV infection?

    <p>HIV replication is controlled by the immune system</p> Signup and view all the answers

    What is the primary mode of transmission for HIV?

    <p>Bodily fluids</p> Signup and view all the answers

    How do the majority of individuals initially experience HIV infection?

    <p>Like an influenza-like illness</p> Signup and view all the answers

    What is the main characteristic of Chlamydia trachomatis that makes it an obligate intracellular pathogen?

    <p>It cannot produce ATP.</p> Signup and view all the answers

    Which treatment is commonly used for acute Herpes Simplex infections?

    <p>Aciclovir</p> Signup and view all the answers

    What is the gold standard method for diagnosing Herpes Simplex infections?

    <p>PCR</p> Signup and view all the answers

    How can neonatal herpes occur?

    <p>Through vaginal or cesarean delivery from an infected mother.</p> Signup and view all the answers

    What is a common complication for females with untreated Chlamydia infections?

    <p>Ectopic pregnancy</p> Signup and view all the answers

    Which of the following symptoms is commonly associated with genital herpes during the primary infection phase?

    <p>Lesions on genitals</p> Signup and view all the answers

    What percentage of herpes infections may be asymptomatic?

    <p>75%</p> Signup and view all the answers

    Which test provides high specificity for diagnosing Chlamydia due to its definitive results?

    <p>Culturing the sample</p> Signup and view all the answers

    Which of the following features of HSV-1 distinguishes it from HSV-2 in terms of transmission?

    <p>Commonly transmitted by saliva.</p> Signup and view all the answers

    What approach is recommended to prevent herpes transmission during an active outbreak?

    <p>Abstinence from sexual activity</p> Signup and view all the answers

    What is a common complication of untreated Gonorrhoea in females?

    <p>Chronic pelvic pain</p> Signup and view all the answers

    Which stage of Syphilis is characterized by a painless primary chancre?

    <p>Primary stage</p> Signup and view all the answers

    What is the primary mechanism of damage caused by Neisseria gonorrhoeae?

    <p>Inflammatory response of the host</p> Signup and view all the answers

    What is the recommended initial treatment for Gonorrhoea?

    <p>Intramuscular ceftriaxone with azithromycin</p> Signup and view all the answers

    What is the typical incubation period for Syphilis after contact with an infected partner?

    <p>9-90 days</p> Signup and view all the answers

    Which test is used to visualize Gram-negative intracellular diplococci for diagnosing Gonorrhoea?

    <p>Microscopy of urethral discharge</p> Signup and view all the answers

    In which age group is the prevalence of infections caused by Treponema pallidum highest?

    <p>18-24</p> Signup and view all the answers

    What is the ID50 for Treponema pallidum, indicating the infective dose required for 50% of subjects to become infected?

    <p>60 organisms</p> Signup and view all the answers

    What type of test is the RPR (Rapid Plasma Reagin) test classified as?

    <p>Non-treponemal test</p> Signup and view all the answers

    Which is NOT a common symptom observed with Gonorrhoea infections?

    <p>Painless ulcerations</p> Signup and view all the answers

    Study Notes

    STI Principles

    • 500 million new STI cases each year
    • Factors contributing to the high burden of disease:
      • Lack of education regarding prevention and existence of STIs
      • Taboo surrounding STIs, hindering testing and diagnosis
      • Long asymptomatic periods allowing for transmission
      • STIs are not curable, but not usually lethal
      • Individuals may be unwilling to get tested
      • Risky behaviors can be difficult to change
    • Most STIs are fragile and survive poorly outside the body, requiring close contact or direct transmission of body fluids for spread.
    • Coinfections are possible and one STI may increase the risk of others. For example, HIV transmission increases five to tenfold with other STIs due to increased white blood cells.
    • This highlights the importance of testing for multiple STIs simultaneously.

    Microbiological Causes of Disease

    • Cervicitis and urethritis: Inflammation of the cervix and urethra.
      • Symptoms include dysuria, itching, and discharge.
      • Organisms involved: Neisseria gonorrhoea, Chlamydia trachomatis, Mycoplasma genitalium, and Herpes simplex virus (HSV)
    • Vaginosis: Disruption of vaginal flora.
      • Symptoms include unpleasant odor and vaginal discharge.
      • Organisms involved: Trichomonas vaginalis, Candida albicans, and Gardnerella vaginalis
    • Genital ulcer:
      • Organisms involved: HSV, Chlamydia trachomatis, Treponema pallidum, and Haemophilus ducreyi
    • Pelvic inflammatory disease (PID): Causes chronic pelvic pain, fallopian tube damage, and infertility.
      • Organisms involved: Chlamydia trachomatis, Neisseria gonorrhoea, Gardnerella vaginalis, and Mycoplasma hominis

    Viral Causes of STIs

    • Human Papillomavirus (HPV):
      • Over 200 different types of HPV, with around 30 million new infections and 250,000 cancer deaths annually.
      • Around 40 types infect the genital tract, with 80% of females acquiring a genital HPV infection by age 50.
      • Some types are linked to cervical, anal, vulvar, and penile cancer.
    • Human Immunodeficiency Virus (HIV):
      • Around 40 million people are infected with HIV, resulting in around 1 million deaths annually.
      • Two types: HIV-1 and HIV-2, both retroviruses belonging to the lentivirus family.
      • Causes acquired immunodeficiency syndrome (AIDS) by infecting CD4+ cells, including T helper cells, monocytes, dendritic cells, and microglia.
    • Herpes Simplex (HSV):
      • Approximately 500 million people are infected globally, with around 20 million new infections per year.
      • There are two types: HSV-1 and HSV-2.
    • Hepatitis B (HBV):
      • More than 200 million people are infected with HBV, primarily relevant as a gastrointestinal virus.

    Human Papillomavirus (HPV)

    • Viral Structure:
      • Double-stranded DNA virus.
      • Viral proteins E6 and E7 disrupt p53 and Rb, leading to cell overgrowth.
    • Transmission:
      • Transmitted through skin-to-skin contact, not necessarily involving sexual intercourse.
      • Enters squamous epithelial cells through microabrasions and replicates on keratinocytes.
      • Often resolves naturally, but can cause warts or integrate into the genome, increasing the risk of cancer.
    • Diagnosis:
      • Incubation period: 1-6 months.
      • Clinical observation of lesions.
      • Subclinical diagnosis with dilute acetic acid, causing whitening of warts.
      • Cytology used to detect early epithelial changes:
        • Papanicolaou (Pap) smear: Aims to detect early epithelial changes, identify cervical intraepithelial neoplasia (CIN), and early cervical cancers.
    • Treatment/Prevention:
      • Treatment:
        • Cosmetic, non-specific, and aims to control growth.
        • Methods include: Liquid nitrogen, excision, or caustic agents.
      • Prevention:
        • Nonavalent vaccine: Protects against infection, including HPV-16, 18, 6, and 11.
        • Earlier vaccination leads to better cancer prevention.

    Human Immunodeficiency Virus (HIV)

    • Transmission:
      • Transmitted through bodily fluids, including sexual contact, blood, and mother-to-child (vertical) transmission.
      • Other STIs increase the likelihood of transmission.
    • Pathogenesis:
      • Acute Phase: Massive loss of CD4 T cells, leading to a weakened immune system and high viral load.
      • Chronic Phase: Immune system partially controls HIV replication but results in chronic immune activation.
      • AIDS Onset: Marked by severe immunocompromise, leading to various infections and tumors.
    • Treatment:
      • Drugs target reverse transcriptase, with examples including:
        • Nucleoside reverse transcriptase inhibitors (NRTIs)
        • Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
        • Protease inhibitors
        • Fusion inhibitors
      • Effective treatment can prevent death and infectivity.

    Herpes Simplex (HSV)

    • Epidemiology:
      • Two types of HSV: HSV-1 and HSV-2.
      • HSV-1: Transmitted through saliva, causing oral cold sores and 50% of new genital herpes.
      • HSV-2: Transmitted through sexual contact, causing genital blisters and ulcers.
    • Pathogenesis:
      • 75% of infections are asymptomatic.
      • Primary lesions: Form 4-7 days after infection, usually on the penis and vulva but can be intravaginal.
      • Secondary lesions: Typically group together at similar stages of development.
      • Neonatal herpes: Serious consequences with skin, eye, cognitive, organ dysfunction, and death.
    • Diagnosis:
      • Initial diagnosis: Based on clinical symptoms.
      • Gold standard: PCR (faster and more sensitive than viral culture).
      • HSV antigen detection: Looks for IgG against glycoprotein G.
    • Treatment:
      • Antiviral drugs: Reduce symptom severity and time to resolution (eg. Aciclovir, valaciclovir, famiciclovir).
      • Prevention:
        • Avoid sexual contact when lesions are present.
        • Consistent condom use.

    Bacterial Causes of STIs

    • Chlamydia trachomatis (Chlamydia):
      • Around 130 million infections per year, common globally.
      • Causative agent: Chlamydia trachomatis, an obligate intracellular bacterium.
      • Symptoms:
        • Manifest 7-14 days after infection, with watery/mucopurulent discharge and dysuria.
        • Often asymptomatic.
      • Complications:
        • Can cause chlamydial cervicitis and urethritis.
        • More serious complications in females: PID, chronic pain, ectopic pregnancy, and infertility.
    • Neisseria gonorrhoea (Gonorrhoea):
      • Causes around 78 million infections per year.
      • Causative agent: Neisseria gonorrhoea, a Gram-negative diplococci that only infects humans.
      • Pathogenesis:
        • Enters through vaginal, urethral, throat, and rectal mucosa.
        • Initially attaches via pili with high antigenic variation.
        • Invades non-ciliated epithelial cells and replicates in vacuoles.
        • Damage primarily results from the inflammatory response.
      • Symptoms:
        • Observed within 2-7 days, featuring vaginal or urethral discharge and dysuria.
        • Females are often asymptomatic.
      • Complications:
        • Rare in males.
        • Common in females (due to asymptomatic nature): PID, chronic pelvic pain, fallopian tube damage, infertility, and bloodstream infections.
    • Treponema pallidum (Syphilis):
      • Causes around 6 million infections per year, increasing prevalence in Australia.
      • Causative agent: Treponema pallidum.
      • Transmission:
        • Transmitted through sexual contact, with a 15-30% risk of infection after contact with an infected partner.
        • ID50: Around 60 organisms.
        • Incubation period: 9-90 days (average 2-4 weeks).
        • Vertical transmission possible through the placenta.
      • Stages:
        • Primary: Painless primary chancre, typically a single lesion.
        • Secondary: Systemic spread of treponema, characterized by an infectious skin rash.
        • Latent: No symptoms present, but infection persists.
        • Tertiary: Cell-mediated response to chronic infection leading to damage and gummas (chronic inflammatory granulomas), cardiovascular syphilis, and neurosyphilis.
    • Haemophilus ducreyi:
      • Causes chancroid, less common in Australia but widespread in Africa and South America.

    Treponema pallidum (Syphilis)

    • Diagnosis:
      • Microscopy: Can be used on exudate from the primary chancre.
      • Serology:
        • Non-treponemal tests: Detect antibodies against cardiolipin (indicate host damage).
          • Examples: RPR (rapid plasma reagin test) and VDRL (venereal disease research laboratory test).
        • Treponemal tests:
          • Examples: ELISA (antibody detection), TPHA (T.pallidum HaemAgglutination assay), and FTA-ABS (fluorescent treponemal antibody-absorbed test).
    • Treatment:
      • High-dose penicillin (doxycycline and erythromycin used for penicillin allergies).
    • Prevention:
      • Safe sex, early diagnosis, and treatment prevents late-stage complications.

    Other Genital Infections

    • Trichomonas vaginalis:
      • Causative agent: Trichomonas vaginalis, a flagellated protozoon.
      • Causes trichomoniasis, with around 143 million infections annually.
      • Symptoms:
        • In women: Cervicitis, malodorous profuse frothy vaginal discharge, itch, or soreness.
        • Often asymptomatic in women and most men.
      • Transmission:
        • Through vaginal, oral, or anal sexual intercourse.
    • Candida albicans:
      • Causative agent: Candida albicans, a diploid fungus.
      • Causes vaginal candidiasis (thrush), a common overgrowth of the normal vaginal flora.
      • Symptoms:
        • Irritation, inflammation, cheesy discharge, and dysuria.
      • Predisposing factors:
        • Hormonal changes, diabetes, reduced cell-mediated immunity, antibiotic treatment, and other factors impacting the normal flora.
    • Treatment:
      • Topical or oral antifungals (eg. fluconazole).

    STIs

    • 500 million new STI cases every year
    • Lack of education, taboo, asymptomatic nature, difficulty changing behavior, and reluctance to be tested are factors contributing to the burden of STIs.
    • Most STIs are fragile and survive poorly outside the body
    • Multiple infections can occur simultaneously, and one infection can increase the likelihood of others.

    Causes of Disease

    • Cervicitis and urethritis are characterized by inflammation of the cervix and urethra.
    • Organisms causing cervicitis and urethritis include Neisseria gonorrhoea, Chlamydia trachomatis, Mycoplasma genitalium, and Herpes simplex virus (HSV).
    • Vaginosis causes unpleasant odour, vaginal discharge, and results from disruption of the vaginal flora.
    • Organisms causing vaginosis include Trichomonas vaginalis, Candida albicans, and Gardnerella vaginalis.
    • Genital ulcers can be caused by HSV, Chlamydia trachomatis, Treponema pallidum, and Haemophilus ducreyi.
    • Pelvic inflammatory disease (PID) can lead to chronic pelvic pain, damage to the fallopian tubes, and infertility.
    • Organisms causing PID include Chlamydia trachomatis, Neisseria gonorrhoea, Gardnerella vaginalis, and Mycoplasma hominis.

    Viral STIs

    • Human papillomavirus (HPV), human immunodeficiency virus (HIV), HSV, and Hepatitis B (HBV) are commonly encountered viral STIs.

    Human Papillomavirus (HPV)

    • Around 30 million new infections and 250,000 cancer deaths occur annually due to HPV.
    • HPV is a double-stranded DNA virus with over 120 types, 40 of which infect the genital tract.
    • HPV can cause cervical, anal, vulvar, and penile cancer.
    • HPV-16 and 18 are found in 64-79% of cervical cancers, with types 31 and 45 also considered high risk.
    • Transmission occurs via skin-to-skin contact and does not require sexual intercourse.
    • HPV enters squamous epithelial cells through microabrasions and replicates on keratinocytes.
    • The infection often resolves naturally.
    • HPV generates warts as its viral proteins E6 and E7 disrupt p53 and Rb, leading to uncontrolled cell growth and the development of warts.
    • Integration of HPV into the host genome increases the risk of cancer.

    HPV Diagnosis and Treatment

    • The incubation period for HPV is 1-6 months.
    • Clinical observation of lesions is used for diagnosis.
    • Subclinical diagnosis involves the use of dilute acetic acid to cause whitening of warts.
    • Diagnosis aims to prevent associated cancers, and is achieved through cytology, including the Pap smear test, which detects early epithelial changes.
    • Treatment is cosmetic, non-specific, and focuses on controlling wart growth.
    • Methods include liquid nitrogen, excision, or caustic agents.
    • Preventive nonavalent vaccines are available and protect against infection, including HPV types 16, 18, 6, and 11.
    • Early vaccination is crucial for preventing cancer.

    Human Immunodeficiency Virus (HIV)

    • Approximately 40 million people are infected with HIV, leading to approximately 1 million deaths each year.
    • HIV 1 and 2 are retroviruses of the lentivirus family that encode reverse transcriptase.
    • HIV causes acquired immunodeficiency syndrome (AIDS) and infects CD4+ cells, including T helper cells, monocytes, dendritic cells, and microglia.
    • HIV transmission occurs through bodily fluids and does not always involve sexual contact.
    • HIV can be transmitted through contaminated blood products, needle sharing, or from mother to child.
    • Sexual transmission is common.
    • Other STIs increase the risk of HIV transmission.

    HIV Pathogenesis and Treatment

    • The initial acute phase of HIV infection is characterized by a massive loss of CD4 T cells, a weakened immune system, high viral load, and flu-like symptoms.
    • The chronic phase is characterized by controlled HIV replication by the immune system but with chronic immune activation, which leads to opportunistic infections and lasts several years.
    • AIDS onset is marked by various diseases due to HIV-induced immunocompromise, including infections in unusual tissues and cancers such as Kaposi's sarcoma and B cell lymphoma.
    • Antiretroviral drugs target reverse transcriptase in HIV replication, including nucleoside RT inhibitors (NRTI), non-nucleoside RT inhibitors (NNRTI), protease inhibitors, and fusion inhibitors.
    • With proper treatment, individuals with HIV can live long and healthy lives.

    Herpes Simplex (HSV)

    • Approximately 500 million people are infected with HSV, with around 20 million new infections annually.
    • HSV is a double-stranded DNA virus with two types: HSV-1 and HSV-2.
    • HSV-1 is transmitted through saliva and causes cold sores and genital herpes.
    • HSV-2 is transmitted through sexual contact and causes genital sores.
    • 75% of HSV infections are asymptomatic.
    • Symptoms include the formation of primary lesions 4-7 days after infection, typically on the penis or vulva.
    • Symptoms can include pain, itching, burning sensation, dysuria, fever, headache, malaise, myalgias, and inguinal lymphadenitis.
    • Lesions heal over 3-4 weeks but recurrence is common, with 70-90% of individuals experiencing a recurrence within the year.
    • Primary lesions are multiple and widespread, while recurrent lesions are grouped and at the same stage of development.
    • Neonatal herpes can occur due to exposure to HSV during childbirth, leading to serious consequences such as skin and eye disease, cognitive impairment, organ dysfunction, and death.
    • Elective caesarean sections are recommended to prevent neonatal herpes.

    HSV Diagnosis and Treatment

    • Initial diagnosis relies on clinical symptoms, but PCR is considered the gold standard due to its sensitivity for HSV detection.
    • Viral culture has a poor sensitivity.
    • HSV antigen detection tests are also available and look for IgG antibodies against glycoprotein G.
    • Treatment with antiviral drugs reduces symptoms and time to resolution.
    • Aciclovir (IV or oral), valacyclovir, and famciclovir are commonly prescribed; topical use is not recommended.
    • To prevent transmission, individuals with HSV should avoid sexual contact while lesions are present and use condoms consistently.
    • Condom use reduces but does not eliminate the risk of HSV transmission.

    Bacterial STIs

    • Chlamydia trachomatis, Neisseria gonorrhoea, Treponema pallidum, and Haemophilus ducreyi are commonly encountered bacterial STIs.

    Chlamydia trachomatis (Chlamydia)

    • Around 130 million new infections occur annually with Chlamydia trachomatis.
    • Chlamydia trachomatis is an obligate intracellular bacterium and an ATP parasite.
    • It causes chronic infections.
    • Various serotypes of Chlamydia trachomatis exist: A, B, and C cause trachoma; D-K cause genital infections; L1, 2, and 3 cause lymphogranuloma venereum (LGV).
    • Symptoms of chlamydia infection typically appear 7-14 days after infection, including watery or mucopurulent discharge and dysuria.
    • Many individuals are asymptomatic.

    Chlamydia Complications, Diagnosis, and Treatment

    • Chlamydia can cause cervicitis and urethritis.
    • Complications are less common in men but more significant in women, including PID, chronic pain, ectopic pregnancy, and infertility.
    • Symptoms do not distinguish between chlamydia and gonorrhea, requiring laboratory testing for diagnosis.
    • Cell culture is highly specific but not sensitive and takes 48-72 hours.
    • Direct antigen methods such as ELISA or immunofluorescence are used, but have low sensitivity.
    • PCR-based methods, performed on urine samples, are rapid (2-4 hours) and are highly sensitive.
    • Chlamydia is a curable disease.
    • Treatment involves a single dose of azithromycin or a 10-day course of doxycycline.
    • Given the high rate of co-infection (5%) with Neisseria gonorrhoea, testing for both STIs is recommended.

    Neisseria gonorrhoea (Gonorrhea)

    • Gonorrhea causes an estimated 78 million infections annually.
    • Neisseria gonorrhoea is a Gram-negative diplococcus that infects humans and survives poorly in the environment.
    • Gonorrhea typically enters through the vaginal or urethral mucosa, but can also infect the throat and rectum.
    • The bacterium attaches via pili, which exhibit high antigenic variation.
    • Invades non-ciliated epithelial cells and replicates in the vacuole, releasing through the basement membrane.
    • Immune response and bacterial factors contribute to the symptoms and host damage.
    • Vertical transmission during vaginal delivery is possible.

    Gonorrhea Symptoms, Complications, and Diagnosis

    • Symptoms typically appear within 2-7 days and include vaginal or urethral discharge and dysuria.
    • Females are often asymptomatic.
    • Complications are more common in females, including PID, chronic pelvic pain, fallopian tube damage, infertility, and bloodstream infections.
    • Diagnosis involves testing as purulent discharge is hard to distinguish from chlamydia.
    • PCR is the most common method, but microscopy of urethral discharge can visualize Gram-negative intracellular diplococci.

    Gonorrhea Treatment and Prevention

    • Treatment involves IM ceftriaxone with azithromycin.
    • Resistance to penicillin is significant.
    • Gonorrhea is a notifiable disease requiring partner notification and contact tracing.
    • Safe sex is essential for prevention.
    • Testing for other STIs is recommended due to the high likelihood of co-infection with chlamydia.

    Treponema pallidum (Syphilis)

    • Syphilis causes approximately 6 million new infections each year.
    • Syphilis is caused by Treponema pallidum and has four stages if left untreated: primary, secondary, latent, and tertiary.
    • Tertiary syphilis can lead to neurosyphilis and cardiovascular syphilis.

    Syphilis Transmission and Symptoms

    • Syphilis is transmitted through sexual contact, with a 15-30% risk of infection after contact with an infected partner.
    • The incubation period is 9-90 days, with an average of 2-4 weeks.
    • Vertical transmission can occur through the placenta.
    • Primary syphilis presents as a painless primary chancre, typically a single lesion, on the cervix, labia, urethra, penis, or ano-rectum.
    • Secondary syphilis presents as a highly infectious skin rash that resolves in 3 months.
    • Tertiary syphilis develops in 3-30 years and occurs in 30% of untreated individuals.
    • Tertiary syphilis leads to soft tissue destruction, gummas, cardiovascular syphilis, and neurosyphilis.

    Syphilis Diagnosis and Treatment

    • Microscopy can be performed on exudate from the primary chancre.
    • Serological testing includes non-treponemal tests and treponemal tests.
    • Non-treponemal tests involve detecting antibodies against cardiolipin, a host membrane component indicative of host damage.
    • Examples include the RPR and VDRL tests, which have lower sensitivity and specificity.
    • Treponemal tests include ELISA, TPHA, and FTA-ABS tests, which detect antibodies specific to Treponema pallidum.
    • Treatment involves high-dose penicillin.
    • Doxycycline and erythromycin are used in penicillin-allergic individuals.

    Syphilis Prevention

    • Safe sex practices, early diagnosis, and prompt treatment are essential for preventing late-stage complications of syphilis.

    Other Genital Infections: Trichomonas vaginalis and Candida albicans

    Trichomonas vaginalis

    • Trichomonas vaginalis is a flagellated protozoan that causes trichomoniasis, with an estimated 143 million cases annually.
    • Trichomoniasis presents with cervicitis, malodorous frothy vaginal discharge, itch, and soreness in women.
    • 50% of women are asymptomatic, and most men are also asymptomatic.
    • Transmission occurs through vaginal, oral, or anal sexual intercourse.
    • Diagnosis is achieved through PCR on the first pass urine or a high vaginal swab.
    • Treatment involves metronidazole or tinidazole.

    Candida albicans

    • Candida albicans is a diploid fungus that is a normal part of oral, gut, and vaginal flora.
    • Overgrowth of Candida albicans leads to vaginal candidiasis (thrush).
    • Symptoms include irritation, inflammation cheesy discharge, and dysuria.
    • Predisposing factors include hormonal changes, diabetes, reduced cell-mediated immunity, and antibiotic treatment.

    Candida albicans Treatment

    • Treatment involves topical or oral antifungals, such as fluconazole.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Microbiology PDF Notes

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser