Week 1 - F(1) - Microbiology of genital tract infection

Question 1

What are three main bacterial sexually transmitted infections? (STIs)

Answer 1

Chlamydia trachomatis (chlamydia) Neisseria gonorrhea (gonorrhea) Treponema pallidum (syphilis)

Question 2

What are four types of viral STI?

Answer 2

Human papillom virus (HPV) Herpes simplex virus (HSV) Hepatitis HIV (human immunodeficiency virus)

Question 3

Name three parasitic STIs?

Answer 3

Trichomnas vaginalis Phthirus pubis (pubic lice or crabs) Scabies - sarcoptes scabie

Question 4

The majority of things in the genital tract are transmitted sexually If both gonococcus or chlamydia trachomatis infect the urethra, what is the difference in the symptoms?

Answer 4

Gonococcus causes an intense inflammatory response recruiting a large number of neutrophils leading to a large purulent discharge Chlamydia trachomatis is only likely to produce a mild watery discharge or no symptoms at all

Question 5

Human to human transmission is the main source of STI What STI can sometimes come from inanimate sources? (it is one of the parasitic trio)

Answer 5

Trichomonas vaginalis, a parasitic STI, can sometimes come from an inanimate source

Question 6

Because STDs are mucosal diseases, need to take a history to understand what mucosal surfaces are in contact with what Why can STIs be recurring?

Answer 6

STIs can reoccur after treatment as the human body does not make memory antibodies to fight the disease and therefore we are continually susceptible

Question 7

30% of unselected females are colonised with small numbers of Candida and have no symptoms Ie presence of candida does not mean one has the infection What are four predisposing factors for candida infection? (candidia is not ususally associated with being an STI)

Answer 7

Recent antibiotic therapy High oestrogen levels (pregnancy and certain types of contraception) Poorly controlled diabetes The immunocompromised patients

Question 8

Which gender is candida more common in?

Answer 8

Candida infections are more common in females as they cause have higher oestrogen levels which is an associated risk factor with candidia

Question 9

What is the species of candida causing infection? (remember candidia is the genus) What is the common presentation of candida?

Answer 9

Candidia albicans is the common cause of candida infection Presents as an intensely itchy white vaginal discharge

Question 10

What is taken for the clinical diagnosis of candida?

Answer 10

High vaginal swab for culutre is taken in candida

Question 11

What is the common name for candida of the vagina? What is the treatment of candidia albicans of the vagina?

Answer 11

Common name for candida of the vagina is vaginal thrush

Treatment -

• topical clotrimazole pessary + clotrimazole cream or
• Oral fluconazole + clotrimazole cream

Question 12

If it is a non albicans candidiasis infection, will it respond to treatment using the ‘azole’ anti-fungals?

Answer 12

Usually will not respond to treatment and requires referral to sexual health clinic

Question 13

What is seen on a gram film of candida albicans?

Answer 13

Can see the presence of hyphae and budding in candida albicans

Question 14

How does candidia balantis (balantis is the symptoms, still usually caused by candida albicans) usually present?

Answer 14

Balanitis is inflammation of the glans penis.

Candidia balaantis has a typical spotty, red and inflamed rash on the penis

Question 15

Prostatitis has three different classifcations, acute, chronic and chronic prostatis/chronic pelvic pain syndrome (CP/CPPS) What are the symptoms of prostatitis? What are causes of prostatitis?

Answer 15

Main symptoms are the same as UTI - urgency, pain on urination and blood in urination plus associated with pain in penis, and lower back (rectum area) Prostatitis can be caused by those who have had a UTI, STI or other causes

Question 16

What age group is STI causing prostatitis associated with? What are the tests carried out to find the cause of acute bacterial prostatitis?

Answer 16

STI causing prostatitis is associated with patients aged below 35 years

Tests

• Clinical signs + MSSU (mid-stream sample of urine) for culture and sensitiviy - looks for UTI
• First pass urine sample looking for chlamydia PCR
• Urethral swab to look for gonorrhea

Question 17

What is the treatment of prostatitis? What is the treatment if risk of C.difficile?

Answer 17

Treatment of prostatitis Quinolones - oxflaxacin for 28 days or ciprofloxacin for 28 days If high risk of C.difficile then use trimethorpim to treat the prostatitis

Question 18

Define: True positive True negative False positive False negative

Answer 18

• True positive - a test result that identifies a condition when the disease is present
• True negative - a test result that doesnt identify the condition and the disease is absent
• False positive - a test result that identifies the condition when the condition is absent
• False negative - a test result that doesnt identify the condition and the condition is present

Question 19

Define sensitivity?

Answer 19

Sensitivity - Proportion of those who were correctly identified with the condition over the total number that have the disease (True positive divided by (True positive +False negative)) (total number who have the disease tested correctly over total number who have the disease)

Question 20

Define specificity?

Answer 20

Specificity - Proportion of those who were correctly identified as negative over the total who actually do not have the condition (True negative divided by (False positive + True negative)) (total number identified not having the disease correctly, over total number who dont have the disease)

Question 21

Describe positive predictive value and negative predictive value?

Answer 21

Positive predictive value - this is the number who correctly tested positive over the total number that tested positive Negative predicative value - this is the number who correctly tested negative over the total who tested negative

Question 22

Define sensitivity, specificity, positive predicative value (PPV), negative predicative value(NPV)?

Answer 22

Sesntiivity - proportion who correctly identified as positive for the disease over the total number who have the disease Specificity - proportion who were correctly identified as negative for disease over number who don’t have disease PPV - proportion who correctly identified as positive for the disease over the number who were tested as positive NPV - proportion who correctly identified as negative for the disease over number who tested as negative

Question 23

STI coinfections are common What two infect the urethra? (most commonly) What do genital ulcers increase the likelihood of having?

Answer 23

Chlamydia and gonorrhoea infect the urethra Genital ulcers increase the likelihood of HIV acquisition

Question 24

What is the bacteria that dominates the normal healthy vaginal flora?

Answer 24

This is the lactobacillus

Question 25

What does the lactobacillus produce that suppresses the growth of other bacteria? What other bacteria slightly colonise the vagina? (remmeber the one for neonatal meninigits)

Answer 25

Lactobacillus prodcues lactic acid (+/- hydorgen peroxide) which gives the vagina an acidic pH which suppreses the growth of other bacteria Group B haemolytic strptococcus - this can cause neonatal meningitis and strep viridans (group A strep) also colonise, candidia also sometimes

Question 26

The normal vaginal flora contains lactic acid and hydrogen peroxide–producing lactobacilli such as what? When yoghurts say they have lactobacillus acidopholus which helps with vaginal flora, is this true?

Answer 26

The normal lactobacilli are lactobacillus crispatus and lactobacillus jensenii Lactobacillus acidophilus is rarely found in the vaginal flora

Question 27

What does lactobacillus look like on gram stain? What is the normal pH of the vagina?

Answer 27

Lactobacillus stains as gram positive bacilli (rod shaped) Purple for positive on gram stain Normal pH of vagina is 4-4.5

Question 28

Usual vaginal pH is 4 to 4.5 but when you have bacterial vaginosis the pH will be higher (usual alkaline) It is alkaline as normal bacteria replaced by the bacterial (non flora) ones What is the bacteria that replaces the normal vaginal flora in bacterial vaginosis?

Answer 28

Gardnerella vaginalisis

Question 29

What are the sympotoms of bacterial vaginalis due to gardnerella vaginalis?

Answer 29

Foul fishy smelling odour White or green discharge Burning during urination Vaginal itching

Question 30

Gardnerella is a genus of Gram-variable-staining facultative anaerobic bacteria of which G. vaginalis is the only species. What is the test used to detect the fishy like odour in gardnerella vaginalis?

Answer 30

This is the whiff test 10% potassium hydroxide is added to the discharge produced and a fish like odour is smelt

Question 31

To check for gardnerella vaginosis, can test the pH of the vagina, the whiff test shows the fishy odour Another test known as a wet mount test can be carried out in the diagnosis of bacterial vagnisosis. This is where a swab is taken and examined under a microscope What is seen under the microscope in a wet-mount test?

Answer 31

Their is an absence of bacilli cells in the eipthelial swab and instead their is the presence of coccobacilli cells - these are known as clue cells as they give a clue to the diagnosis of bacterial vaginosis

Question 32

What are the four things seen when looking for bacterial vaginosis? Symptoms + three tests basically

Answer 32

Thin, white/yellowish discharge, burning on urination and vaginal itch pH of vagina is greater than 4.5 Whiff tests positive for a fishy odour when 10% potassium hydroxide is added Wet mount reveals the presence of coccobacilli cells instead of bacilli on the vaginal epithelium - these are known as clue cells

Question 33

Women with BV may have increased risk for the acquisition of HIV. What is the treatment of bacterial vaginosis?

Answer 33

Oral metronidazole is given for 7 days

Question 34

In bacterial vaginosis, there is a 30% relapse rate in the condition Is there any benefit in treating the male sexual partner when a woman has bacterial vaginosis?

Answer 34

There is no benefit to treating the male sexual partner

Question 35

What is the commonest bacterial STI in the uk? What areas of the body can it affect?

Answer 35

Chlamydia trachomatis - this bacteria has a biphasic cycle Can affect the rectum, urethra, throat and eyes (male and female) and the endocervix in females

Question 36

Even though chlamydia is a bacteria, why is it referred to as an energy parasite?

Answer 36

This is because chalmydia is an obligate intracellular bacteria

Question 37

What does obligate intracellular bacteria mean for chlamydia trachomatis?

Answer 37

This means that chlamydia thrachomatis is unable to replicate outside of the host cell

Question 38

Why does chlamydia not stain with gram stain?

Answer 38

The basis off a gram stain is that in order to retain the stain you must have peptidoglycan but chalmydia does not have this in the cell wall and therefore cannot undergo staining

Question 39

A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals Chlamydia trachomatis has three different serotype groupings Serovars A-C Serovars D-K Serovars L1-L3 Describe the three different serovars infection?

Answer 39

Serovars A-X - this is known as Trachoma - this infection affects the eyes and is not an STD Serovars D-K - this causes genital infection with the chlamydia trachomatis bacteria Serovars L1-L3- this is a chlamydial infection known as lymphogranuloma venereum

Question 40

What disease is an infection with lymphogranuloma venereum associated with? What is the treatment of an infection with lymphogranuloma venereum?

Answer 40

Lymphogranuloma venereum is associated with proctitis - inflammation of the rectum Treatment of the disease is doxycycline for three weeks

Question 41

What is the 1st line treatment for uncomplicated chlamydia trachomatis? What is given if they are unable to take this? Give the class of both drugs Name the serovars and types of infection for chlamyida trachomatis?

Answer 41

Azithomycin (1g oral dose) for uncomplicated chlamidia Doxycycline 100mg bd x 7 days Azithromycin - macrolide type of antibitoic Doxycycline - tetracycline type of antibiotic Serovars A-C - Trachoma - chlamydia infection of the eyes Serovars D-K - Genital infection Seovars L1-L3 - Lymphogranuloma venereum

Question 42

What group of people are serovars A-C chlamydial infections associated with? What types of STI cause ulcers?

Answer 42

Serovars A-C - Eye infection - Trachoma - associated with babies or in 3rd world countries

Syphilis, HSV, lymphogranuloma venereum

Question 43

What are the highly sensitive an highly specific tests done to diagnosis chlamydia trachomatis and gonococcal infection?

Answer 43

This would be Nucleic acid amplification test or Polymerase chain reaction (NAAT/PCR) - these test for both organisms in one test

Question 44

What sample of urine is taken in males to test for chlamydia trachomatis and neisseria gonorrhea? What swab is taken in women? (remember the one the doctor takes and the swab a women can be instructed to take herself) What sample of urine is taken when testing for a UTI?

Answer 44

Sample of urine for chlamyida and gonococcal infection in men - first pass sample of urine tested Swab taken in women - can self administer a vulvo-vaginal swab or high vaginal swab for women , if clinican is carrying out a speculum anyway, would try an endocervical swab take a mid stream sample of urine (MSSU) when looking for a UTI

Question 45

Neisseria gonococcus Attaches to host epithelial cells and is endocytosed into the cell to replicate within the host cell and are released into the subepithelial space. Descriibe this bacteria on gram stain? What areas does neisseria gonococcus infect? similar to chlamydia trachomatis

Answer 45

It is a gram negative intracellular diploccoi on gram stain (it is pink on gram stain) The bacteria can affect the urethra, rectum, throat and eyes (in males and females) and the endocervix (in females)

Question 46

The neisseria gonococcus Look like “2 kidney beans facing each other” Easily phagocytosed by polymorphs, so often appear intracellularly on a Gram film What is the difference in sympotms between chlamydia trachomatis and neisseria gonorrhea?

Answer 46

Gonococcus causes an intense inflammatory response and therefore recruits a lot of leukocytes (neutrophils - polymorphonuclear cells) and therefore a big purulent discharge Chamydia is likelt to bring a mild watery discharge or no sympotms at all

Question 47

Gonorrhea can replicate inside or outside the body but dies quickly outside, it is therefore known as what type of organism?

Answer 47

It is known as a fastidious organism as it will die outside of the body

Question 48

As neisseria gonorrhea is having an increased resistance, it is important to culture as there is an increased resistance growing Mircoscopy is carried out in sexual and reprodcutive health (SRH) clinics when culturing for N.Gonorrhea, what swabs are these not done on and why are they done on selective agar plates?

Answer 48

The microscopy and culture is not carried out on high vaginal swabs (HVS) or vulvovagina - require endocervical swabs Carried out on selective agar plates as antibiotic medium is used to kill any other bacteria so gonococcus is the only bacteria that will grow

Question 49

Why is it that the culture is only done in Sexual and reproductive health clinics and not done on swabs sent from GPs? If specimen sample is from the GP, what test is done instead?

Answer 49

This is because the N.gonorrhea would die on transport form the GP to microbiology lab and therefore false positive were given NAAT is carried out instead if specimen sample is from the GP

Question 50

What are the advantages of carrying out PCR/NAAT testing over culturing?

Answer 50

Advantages over culture - These tests are highly specific and highly sensitive Much less invasive specimens are required than what is needed in a culture The test is much quicker - hours, not days

Question 51

What are the disadvantages of carrying out PCR/NAAT over culture?

Answer 51

Disadvantages over culture - The PCR/NAAT does not show antibitoic sensitivity and therefore difficult to tract resistance The tests detect dead organisms and therefore must wait 5 weeks post-treatment to re-test for cure

Question 52

What is seen here?

Answer 52

Can see gram negative diplococci on gram stain - can see how the bacteria are intracellular (negative as the stain shows pink organisms)

Question 53

Fellacio - an oral sex act involving the use of the mouth or throat, which is performed by a person on the penis of another person or oneself. Cunnilingus - the technical term for performing oral sex on a woman Pharyngeal gonococcal infection results from orogenital exposure. Is it more efficiently acquired via fellatio or cunnilingus?

Answer 53

Pharngeal gonococcal infection is more efficiently acquired via fellacio

Question 54

Is pharngeal gonoccocal infection more commonly asymptomatic or symptomatic? Ie pharngitic like symptoms

Answer 54

Pharngeal gonoccal infection is more commonly asymptomatic - worth testing for in men with a gonococcal infectiion

Question 55

Many strains of gonorrhoea are now resistant to penicillins, tetracyclines, quinolones (ciprofloxacin/ofloxacin) and most oral cephalosporins What is the current recommended treatment of neisseria gonorrhea? Straight what drug class they are

Answer 55

Intramsucular (IM) ceftriaxone + oral azithromycin Ceftriaxone - cephalosporin Azithromycin - macrolide

Question 56

Is a test of cure recommended in Neisseria gonorrhea? When is it carried out if so? Why is azithromycin given in the treatment of neisseria gonorrhea?

Answer 56

Test of cure is recommended If testing via a NAAT/PCR test, must wait 5 weeks post treatment as these will still detect dead organisms Azithromycin is given to co-treat the gonococcal infection but also to prevent resitance of the gonococcus emerging

Question 57

Differential diagnosis of symptomatic proctitis includes traditional STIs such as what?

Answer 57

Chlamydia trachomatis, neisseria gonorrhea, lymphogranuloma venereum , HSV, syphilis

Question 58

Proctitis is an inflammation of the lining of the rectum. The rectum is a muscular tube that’s connected to the end of your colon. Stool passes through the rectum on its way out of the body. Proctitis can cause rectal pain and the continuous sensation that you need to have a bowel movement. What is the treatment for proctitis when caused by lymphogranuloma venereum?

Answer 58

This would be to treat with 3 weeks of doxycycline

Question 59

Less than 20% of women with gonorrhoea have extragenital infections (extragenital refers to the none reproductive organs being infected) Rare for women to have solely extragenital infection only What is the statistic for men having solely extragenital infections in cases of gonorrhea?

Answer 59

Greater than 50% of men who have gonorrhea have solely extra-genital infections Thus routine screening of MSM (Men who have Sex with Men), but not women, for rectal gonorrhea

Question 60

What organism causes the disease syphilis?

Answer 60

Syphilis is caused by the spirochete organism treponema pallidum

Question 61

Syphilis does not stain with gram stain and cannot be grown on artifical culture so how is it diagnosed?

Answer 61

It can be diagnosed using a PCR reference test or by serology (testing blood for antigens)

Question 62

What are the 4 stages of syphilis? describe them

Answer 62

Primary syphilis - formation of a chancre (painless ulcer) and organism enters bloodstream Secondary syphilis - large numbers of bacteria circulating in blood with rashes at different areas Latent syphilis - no symptoms but lasts for year Late syphilis - cardiovascular and neurological problems many years later

Question 63

Will the chancre in syphilis heal itself? What stage is irreversible? What stage has no symptoms?

Answer 63

The chancre will heal itself in syphilis The late stage of syphilis is irreversible Latent stage has no symptoms

Question 64

What stage of syphilis is this? How long after exposure does it occur and how long can it last?

Answer 64

This is the primary stage - painless chancre Occurs around 3 weeks post-exposure and can last for a further 6 weeks

Question 65

What stage of syphilis is this? When does this occur?

Answer 65

Secondary stage - widespread generalised rash Secondary syphlis usually occurs 2-10 weeks after the chancre first appears about 6 weeks post exposure

Question 66

Syphilis diagnosis - Dark ground microscopy to look for spirochaetes in exudate from 1y and 2y lesions Not done in Tayside – not enough cases to maintain expertise What is usually carried out when dianosing syphilis in the primary stage?

Answer 66

Usually swab of ulcer sent for PCR tests Serology of specific and non specific antibdoies to T.pallidum is carried out to detect the progression of syphilis and confirms diagnosis

Question 67

What are the two non specific serological tests for syphilis? Why are they named non-specific? WHat are they useful for measuring?

Answer 67

This is the VDRL and the RPR test VDRL(Venereal Diseases Research Laboratory) RPR (Rapid Plasma Reagin) They are non-specific as they can give false positives if used for screening for syphilis However are very useful for monitoring the response to therapy

Question 68

Specific serological tests iclude the TPPA and TPHA tests What do these stand for and when are they positive?

Answer 68

Trepnema pallidum particle agglutination assay Treponema pallidum haemagglutination assay These tests remain positive for life once the patient is infected with syphilis

Question 69

IgG and IgM are the other tests in syphilis that are specific What is the screening test in syphilis known as?

Answer 69

Combined IgG & IgM ELISA used as the “screening” test for syphilis

Question 70

What three tests remain positive for lifetime once a person has been infected with syphilis? What three tests will eventually become negative after syphilis treatment? What test is looed at after the clinician has given the antibiotics to treat the syphilis and an expected decrease in this serological test is meant to be seen?

Answer 70

The TPPA, TPHA and the IgG test will remain positive for lifetime after person has been infected with The IgM, the VDRL and the RPR test will become negative after treatment The VDRL test is looked at by the clinican to check for response to the antibitoc as its levels should decrease with treatment progress

Question 71

Syphilis combined IgM & IgG screening test (ELISA test on clotted blood specimen) If this comes back negative, what is then carried out next?

Answer 71

If the combined test comes back negative then the patient does not have syphilis and no additional tests are carried out

Question 72

If the combined IgG and IgM ELISA test comes back positive, what additional tests are carried out?

Answer 72

Measure the IgM ELISA test Measure VDRL and TPPA also

Question 73

What is the treatment for syphilis?

Answer 73

The treatment for syphilis is intramuscular penicillin (Benzathine penicillin is given - aka benzthanine benzylpenicillin aka benzthine Penicillin G)

Question 74

Which virus causes genital herpes?

Answer 74

Herpes simplex virus HSV 1 and HSV 2

Question 75

What does HSV 1 also cause?

Answer 75

Also causes oral herpes

Question 76

In genital herpes, the Virus replicates in dermis and epidermis Gets into nerve endings of sensory and autonomic nerves Inflammation at nerve endings What can this inflammation at nerve endings cause?

Answer 76

This can cause blisters and ulcers - easily deroofed

Question 77

Herpes Virus migrates to sacral root ganglion and “hides” from the immune system there (probably remains for life) Virus can reactivate from there causing recurrent genital herpes attacks (trigger factors for this not understood) How is genital herpes diagnosed? What is the treatment option?

Answer 77

It is diagnosed by deroofing the blister and taking a swab sent in a viral transport medium for PCR Treatment is oral acicylovir

Question 78

What is this?

Answer 78

This is genital herpes

Question 79

What bacterial infection causes trichomoniasis? WHat infection is it similar to?

Answer 79

Trichomoniasis is similar to the infection bacterial vaginosis It is caused by the bacteria trichomonis vaginalis

Question 80

How is trichomoniasis diagnosed? What is used to treat both this and gardnerella vaginalis? WHat is the difference in transmission of bacterial vaginosis (gardnerella vaginalis) and trichomoniasis Itrichomonis vaginalis)?

Answer 80

• Trichomoniasis is diagnosed with a high vaginal swab for microscopy
• Metronidazole
• Trichomoniasis is a sexual transmitted infection
• Bacterial vaginosis is not an STI and simply a change in the normal vaginal flora

Question 81

What is phthirus pubis better known as? What is its treatment?

Answer 81

It is better known as pubic lice (crabs) Treated with malathion lotion