MM+Lecture 11 - Bacterial UTIs, Bacterial STIs PDF

Bacterial urinary tract infections Sexually transmitted bacterialinfections Lecture 11 Intended Learning Outcomes At the end of this learning session, students are expected to be able to: - Name the causative agent, symptoms and treatment of common bacterial urinary tract i...

Bacterial urinary tract infections Sexually transmitted bacterialinfections Lecture 11 Intended Learning Outcomes At the end of this learning session, students are expected to be able to: - Name the causative agent, symptoms and treatment of common bacterial urinary tract infections; - Name the causative agent, symptoms and treatment of common sexually transmitted bacterial infections Bacterial urinary tractinfections Acquisition, aetiology and pathogenesis © Pearson, Microbiology – An Introduction, 15e, 2018 Bacterial infec7on is usually acquired by the ascending route, from the urethra to the bladder and possibly into the ureters and kidneys. Although most cases are acute and short-lived, severe infec7ons may result in prosta77s, kidney 7ssue destruc7on and failure and systemic spread. UTIs can be community-acquired (usually from faecal contamina7on) or nosocomial (mostly due to catheteriza7on). E. coli, staphylococci and P. mirabilis are common causes of community- acquired UTIs, while E. coli and members of the ESKAPE group - oIen expressing MDR - © Elsevier, Mims’ Medical Microbiology 5e, 2014 oIen cause nosocomial UTIs. Risk factors include: The shorter urethra in women (20-30% of women have recurrent UTIs) Catheteriza7on (bacteria are carried directly into bladder during inser7on and use of catheter; catheter disrupts the normal protec7ve func7on of the bladder) Incomplete bladder emptying (due to pregnancy, prosta7c hypertrophy in men over 50 years of age, renal calculi, tumours) Diabetes (diabe7c neuropathy may interfere with bladder func7on) Clinical features, treatment and prevention Acute infec5on of the lower urinary tract is usually characterized by: Dysuria (burning pain on passing urine) Urgency (urgent need to pass urine) Frequency of micturi5on Urine can be cloudy due to the presence of PMNLs and bacteria and may contain blood. Re-infec5ons are common and can be caused by the same microorganism or a different one. Infec5ons of the upper urinary tract can present with kidney infec5on, renal abscesses, loss of kidney func5on and sep5caemia. Although AST should always be the norm, uncomplicated UTIs are usually treated with a 3-day empirical an5bio5c course (e.g.: cotrimoxazole). Complicated UTIs with renal involvement should be treated with a systemic an5bio5c for a longer dura5on (10+ days) aTer ID and AST of the organism. Preven5on: regularly emptying the bladder; avoidance of catheteriza5on whenever possible. Sexually transmittedbacterial infections STIs are increasing !! Resistance to antibiotics New, emerging diseases (mainly viral) Multiple sexual partners Migrant labour and travel Promiscuity “it won’t happen to me” attitudes Many are polymicrobial Mostly poor ethnic minority groups affected Common STIs. Bacterial infec4ons are underlined  Chlamydia trachomatis © Elsevier, Medical Microbiology 7e, 2013 Chlamydia trachomatis can cause genital infections (due to sexual contact) or trachoma, a serious eye infection in neonates (when passing through the birth canal) or adults (by autoinoculation). Chlamydiae enter the host through minute abrasions in mucosal surfaces and result in cell destruction and damage due to the host’s inflammatory response. C. trachomatis can cause an asymptomatic infection (mostly in women – as many as 80% of cases - while men are usually symptomatic) and can also lead to pneumonia in infected neonates. Symptoms develop within 2-7 days of infection and include urethral or vaginal discharge. © Elsevier, Mims’ Medical Microbiology 5e,2014 Persistent infection can lead to chronic inflammation, fibrosis, pelvic inflammatory disease, arthritis, endocarditis, skin lesions, ectopic pregnancies and infertility in women due to fallopian tube damage. C. trachomatis can also present as lymphogranuloma venereum, a systemic infection characterized by an ulcer at the site of inoculation (after a 1-4 week incubation period) that heals, general malaise, fever and myalgias, followed by abscesses in the lymph nodes that discharge on the skin, and possibly fistula and elephantiasis. Treatment: doxycycline, azithromycin Gonorrhoea © Elsevier, Medical Microbiology 7e, 2013 Caused by Neisseria gonorrhoeae, a Gram-negative coccus. Can be an asymptomatic infection (mostly in women) and can be passed vertically during childbirth, causing ophthalmia neonatorum. © Elsevier, Mims’ Medical Microbiology 5e, 2014 Symptoms develop within 2-7 days of infection and include a purulent urethral or vaginal discharge. Persistent infection can lead to chronic inflammation, fibrosis, pelvic inflammatory disease in 10-20% of cases (abscesses in the female reproductive tract), arthritis, endocarditis, skin lesions, ectopic pregnancy and infertility in women due to fallopian tube damage. © Elsevier, Medical Microbiology 7e, 2013 Treatment: cefixime, ceftriaxone. However, drug resistance is a concern. Chemoprophylaxis with 1% silver nitrate, 1% tetracycline, or 0.5% erythromycin eye ointments are routinely used to protect newborns against gonococcal eye infections.  © University of Washington, 2020 Syphilis Caused by the spirochaete Treponema pallidum. Transmitted by: Close sexual contact, through minute abrasions on mucous membranes; Vertical transmission in the first trimester of pregnancy, leading to intrauterine death, congenital abnormalities or a silent infection that appears at +-2 years of age as facial and tooth deformities; Direct contact through minute abrasions on skin after close personal contact (yaws and pinta, endemic to tropical and subtropical countries). Primary syphilis: a highly infectious primary lesion (chancre) appears at the site of infection and presents as a round/oval, painless, hard ulcer that heals within 2 months. © Elsevier, Medical Microbiology 7e, 2013 © University of Washington, 2020 Oral chancre  Secondary syphilis is characterised by a flu-like illness, myalgia, headache, fever, lymphadenopathy and a mucocutaneous rash on the chest, back, palms and soles that heals spontaneously. Signs and symptoms of secondary syphilis o;en are the first observed clinical manifesta=on of syphilis in those prac=cing recep=ve vaginal, oral, or anal intercourse because primary lesions may not be recognized by the pa=ent. Some pa=ents develop wart-like papules (condylomata lata) in skin folds, which are highly infec=ous. Oral and genital patches, organ involvement, eye and neurologic manifesta=ons can also occur at this stage. Latent syphilis ensues for 3-30 years, a;er which symptoms of ter=ary syphilis can appear. Ter=ary syphilis presents with severe symptoms such as destruc=ve gummas lesions in bones, skin, eyes, =ssues and organs (lung, stomach, liver, genitals, breast, brain), general paralysis (neurosyphilis), aor=c lesions/heart failure (cardiovascular syphilis) and is a progressive destruc=ve disease. Treatment: penicillin, doxycycline. © Pearson, Microbiology – An Introduction, 15e, 2018 © University of Washington, 2020 © University of Washington, 2020 Secondary syphilis rash on chest and hands Chancroid © Elsevier, Medical Microbiology 7e, 2013 Haemophilus ducreyi, a Gram-negative streptobacillus causes chancroid, an infection characterized by erythematous papules that rupture, forming painful, soft genital ulcers (3-50mm) and swollen lymph nodes after a 3-7 days incubation period. Treatment: azithromycin, ceftriaxone, erythromycin, ciprofloxacin Granuloma inguinale Granuloma inguinale is caused by Klebsiella granulomatis, a Gram-negative intracellular bacillus, and causes a granulomatous disease affecting the genitalia and inguinal area. After a prolonged incubation of weeks to months, subcutaneous nodules appear on the genitalia or in the inguinal area. The nodules subsequently break down, revealing one or more painless granulomatous lesions that can extend and coalesce into ulcers resembling syphilitic lesions. This infection can become systemic and lead to patient death. Treatment: azithromycin, doxycycline, ciprofloxacin, erythromycin over many weeks. © Elsevier, Medical Microbiology 7e, 2013  Bacterial vaginosis BV is associated with Gardnerella vaginalis, a Gram-variable coccobacillus, and anaerobe colonisa7on/biofilm forma7on and can be sexually transmi=ed from asymptoma7c infected males, causing an ecological disturbance in the vaginal microbiota. It also occurs occasionally in women who have never been sexually ac7ve. © Pearson, Microbiology – An Introduction, 15e, 2018 Lactobacilli maintain pH < 4 and produce bacteriocins -> protec7ve effect. At least 3 of the following signs/symptoms provide a diagnosis: Excessive malodourous vaginal discharge; vaginal pH > 4.5; vaginal epithelial cells coated with bacteria (clue cells); fishy amine-like odour Sequelae: PID, STI acquisi7on, morbidity, PROM, PTB, low birth weight, endometriosis, amnio7c fluid infec7on. Treatment: metronidazole