Lecture 11 Urogenital and Reproductive system Infections PDF - 2024

Week 07 2.34814: Medical Microbiology I 2.34904: Pharmaceutical Med Micro I BOH/BDS Lecture 11: Urogenital Tract and Reproductive system Infections Medical Microbiology 2 ANLangarap-Kilepak Medical Lab Science SMHS-UPN...

Week 07 2.34814: Medical Microbiology I 2.34904: Pharmaceutical Med Micro I BOH/BDS Lecture 11: Urogenital Tract and Reproductive system Infections Medical Microbiology 2 ANLangarap-Kilepak Medical Lab Science SMHS-UPNG Semester 02-2024 The Urinary system The urinary system is composed of organs that regulate the chemical composition and volume of blood and as a result excrete mostly nitrogenous waste products and water. Because it provides an opening to the outside environment, the urinary system is prone to infections from external contacts. The mucosal membranes that line the urinary system are moist and, compared to skin, more supportive of bacterial growth. The Reproductive system shares several of the organs of the urinary system. Its function is to produce gametes to propagate the species and, in the female, support and nourish the developing embryo and foetus. In the same fashion as the urinary system, it provides openings to the external environment and is therefore prone to infections. This is especially true because there is often intimate sexual contact that promotes the exchange of microbial pathogens between individuals. It is not surprising that certain pathogens have adapted to this environment and a sexual mode of transmission. The structure and function of the urinary system; Composed of – two kidneys, two ureters, a single urinary bladder and a single urethra. Certain wastes collectively called urine, are removed from the blood as it circulates through the kidneys. Urine (usually sterile) passes though ureters into the urinary bladder, where it is stored prior to elimination from the body through the urethra. In the female the urethra conveys only urine to the exterior. In the male, the urethra is a common tube for both urine and seminal fluid. Where the ureters enter the urinary bladder, vesicoureteral valves prevent the backflow of urine to the kidneys. Urine is voided through the urethra via the ureterovesical valve. Organs of human urinary system, female The structure and function of the reproductive system; Female – composed of two ovaries, two uterine (Fallopian) tubes, including the cervix, vagina and external genitals. The ovaries produce female sex hormones and eggs. When an ovum is released during ovulation, it enters the uterine tube, where fertilisation may occur if viable sperm is present. The fertilised ovum (zygote) descends the tube and enters the uterus. It implants in the inner wall of the uterus and develops into embryo, the foetus. The external genitals (vulva) include the clitoris, labia and glands that produce a lubricating secretion during copulation. Female reproductive system  Male reproductive system Male- two testes, a system of ducts, accessory glands and the penis. The testes produce male sex hormones and sperm. To exit the body, sperm cells pass through a series of ducts: the epididymis, ductus (vas) deferens, ejaculatory duct, and urethra. The male urethra is usually sterile, except for a few contaminating microbes near the external opening. Normal microbiota of the urinary and reproductive systems. Normally urine is sterile, but may be contaminated with skin microbiota near end of passage through urethra. Urine collected directly from the bladder has fewer contaminants. In females normal microbiota of the vagina is influenced by sex hormones.  For example, within a few weeks after birth, the female infants’ vagina is populated by lactobacilli because oestrogens are transferred from maternal to foetal blood, causing glycogen to accumulate in the vagina. Lactobacilli convert glycogen to lactic acid, and vagina pH becomes acidic, allowing acid- tolerant normal microbiota to grow in vagina. Several more weeks later, oestogen effects diminish and corynebacteria, a variety of cocci and bacilli dominate. So neutral pH till puberty. Oestrogen levels increase at puberty, lactobacilli dominate, vagina again acidic. Disturbances of this ecosystem by the pill or pregnancy, or elimination of normal microbiota due to antibiotics, can lead to vaginitis (inflammation of the vagina). When female reaches menopause, oestrogen levels decrease, composition of microbiota reverts to childhood, vagina at neutral pH. Both pregnancy and menopause increase the risk of urinary tract infections, which are probably related to lower acidity. Spermicides, which inhibit lactobacilli are also associated with urinary tract infections (UTI)  Infections of the urinary tract Pyelonephritis: Urinary tract infection Infection of Mainly due to bowel kidney organisms These colonise the Cystitis: perineum (area between Infection of the anus and the genitals bladder. and then ascend the urethra to reach the Urethritis: bladder and proliferate in Infection of the urine uethra. In some case they travel up the ureter to the kidneys  Urinary tract infections Symptoms – urinary frequency, bladder discomfort, pain on passing urine – may be fevers and flank pain, especially with pyelonephritis, and this can lead to septicaemia Females – 25-50% of women will experience one or more UTIs during their lifetime. More common in women due to heavier perineal contamination with bowel organisms and a shorter urethra – Older women – Bladder prolapse resulting in incomplete emptying of the bladder and urinary retention more common. Retained urine allows bacterial proliferation Males – UTI is uncommon in men and often indicates underlying pathology, such as an enlarged prostate causing urine retention Children – UTIs uncommon. Recurrent UTIs may be due to anatomical abnormalities such as vesico-ureteric reflux  Causes of UTIs – Escherichia coli causes 70-95% of UTIs. – Others S saprophyticus especially in young women Other enteric Gram negative organisms , e.g. Proteus species, Klebsiella species, Enterococcus faecalis – Usually susceptible to a range of antibiotics that can be given orally. More severe infections may require intravenous antibiotics. More resistant organisms (e.g Pseudomonas aeruginosa) seen in patients who have had prior antibiotic therapy NB: Infections associated with urinary catheters have a wide3r range of infecting organisms UTI – causes Ascending bacteria in urethral meatus contaminate the urine in the bladder. Faecal soiling – more common in children and incontinent adults urethrovesical reflux. Reflux of urine (from urethra to bladder) prostatic seeding. Chronic infection in the prostate may cause intermittent UTIs in males. Instrumentation – urethral organisms enter the bladder via instruments (catheterisation) Haematogenous spread - organisms enter the bladder via foci in the kidney. Incomplete emptying of the bladder is the single most important factor in adequate clearing of bacteria from the bladder. Bacterial Diseases of the Urinary System Urinary systems most frequently initiated by inflammation of the urethra or urethritis. Infection of the urinary bladder is called cystitis Infection of the ureters is called ureteritis. Danger from lower UTIs is that they move up ureters and affect kidney(s), causing pyelonephritis. Prostatitis – can be a cause of chronic intermittent UTI in males. Occasionally the kidneys are infected by systemic bacterial diseases such as leptospirosis, the pathogens found excreted in urine. Bacterial infections of the urinary system are usually caused by microbes that enter the system from external sources.  In US about 7 million UTIs per year. About 1 million of nosocomial origin (90% associated with urinary catheters). Due to proximity of anus to urinary opening, intestinal bacteria predominate in UTI. Most infections of urinary tract (UT) caused by E. coli, mostly strains that have become adapted to colonising these organs. Infections with Pseudomonas, because of their natural resistance to antibiotics, are especially troublesome. Diagnosis based on painful urination or full bladder sensation after urination. Urine may be cloudy or have bloody tinge. Counts of 1000/ml of any single type of bacterium or as few as 100/ml of coliforms (e.g. E. coli) are indication of significant infection, especially if leukocytes appear in the urine (pyuria). Bacteria cultured to determine antibiotic sensitivity before therapy. Organisms involved: 60-70% of UTIs caused by E. coli approximately 10 -15% caused by other enteric coliforms (e.g. Klebsiella, Proteus, Citrobacter) Staphylococcus saprophyticus – only in young females Enterococcus faecalis – same situations as the enteric Gram negative bacillus (GNB) S. epidermidis – most commonly post instrumentation S. aureus – more common from haematogenous spread Cystitis inflammation of urinary bladder in females. Symptoms are dysuria (painful, urgent urination) and pyuria. Urinary tract infections in women 8 times that of men due to female urethra closer to anal opening than men. Most due to E. coli. Second most common cause is Staphylococcus saprophyticus. Trimethoprim- sulfamethoxasole clears it up quickly. Fluoroquinolone or ampicillin if drug resistance encountered. Pyelonephritis In 25% of cases, cystitis may progress to pyelonephritis, inflammation of one or both kidneys. Fever or flank or back pain. In females it is a complication of lower UTI. 75% caused by E. coli. Generally results in bacteraemia,. If it becomes chronic, scar tissue forms in kidneys and impairs function. Diagnosis blood cultures and Gram stain Potentially life- threatening so intravenous, extended-term administration of broad- spectrum antibiotics, such as a second or third generation cephalosporin. Leptospirosis Primarily a disease of domestic or wild animals but passed to humans, sometimes causes severe kidney or liver disease. Causative agent is spirochaete, Leptospira interrogans. Infected animals shed bacteria in urine for extended periods. Humans infected when in contact with urine- contaminated water, soil or animal tissue. People whose occupation exposes them to animals/animals products are those at risk. Pathogens enters through minor skin abrasions or via mucous membranes. When ingested enters mucosa of upper digestive system. In US, dogs, cats, common sources. Incubation 1-2 weeks, headaches, muscular aches, chills, fever, appear abruptly. Several days later, acute symptoms disappear and temp returns to normal. Few days later, second episode may occur. Then kidneys, liver may become infected (Weil’s disease). Kidney failure is common cause of death. Recovery gives immunity only to particular serovar involved. Urban poor in US, 16% positive for infection. Doxycycline (a tetracycline) for treatment, but antibiotics don’t work well in later stages of infection. Fungal Disease of the Reproductive Systems Vaginal infections by yeast-like fungi of the genus Candida. Candida albicansis the most common species; but also C. glabrata. C. albicans often grows on mucous membranes of mouth, intestinal tract, genitourinary tract. Infections usually result of opportunistic overgrowth when competing microbiota are suppressed by antibiotics. It is responsible for occasional cases of NGU in males or vulvovaginal candidiasis, the most common cause of vaginitis. The lesions produce more irritation than oral thrush. Pruritus (itching) and a thick, yellow, cheesy discharge. As it is an opportunistic predisposing conditions enable it to take hold. Oral contraceptives, pregnancy, hormones. Frequent in diabetic women. Diagnosed by microscopic identification from scrapings of lesions. Treatment with topical application of antifungal drugs such as clotrimazole and miconazole or single oral dose of fluconazole. Protozoan Diseases of the Reproductive Systems Trichomoniasis Anaerobic protozoan Trichomonas vaginalis normal inhabitant of vagina in females and urethra in males. It is usually sexually transmitted. Men can carry the organism asymptomatically. It is often accompanied by co-infection with gonorrhoea. Incidence highest in women with multiple sexual partners. In response to protozoan infection, the body accumulates leukocytes at infection site. The resulting discharge is profuse, greenish-yellow with foul odour. Vaginal soreness, itching, dysuria common. Incidence is higher than gono or chlamydia, but benign disease and not reportable. May cause preterm delivery, low birth weight. Diagnosis by microscopic examination of organisms in discharge. Treatment is by oral metronidazole administered to both sex partners.  MSU for UTI diagnosis Sample – midstream urine (MSU) – first portion of urine is contaminated by urethral bacteria so it is discarded. Midstream sample should contain uncontaminated urine from the bladder MSU tested by Dipsticks – useful screening test, but can get false positives and false negatives. UTI usually has high white cell count (measured by leucocyte esterase activity) and low nitrate levels Microscopy - Urine contains many white cells, usually >100/microlitre of urine. Epithelial cells suggest an Yellow arrow neutrophils Red arrow bacteria improperly collected sample contaminated with vulval organisms. Gram stain may show organisms Culture - Significant levels are >1000 organisms /ml of urine for cystitis and >10,000/ml for pyelonephritis in adults – different criteria for children Treatment of UTIs Uncomplicated UTIs in young women may resolve without antibiotics, but usually treated to provide early relief of symptoms These are usually treated with antibiotics that are primarily active in the urine (eg, trimethoprim) Complicated infections (eg pyelonephritis, recurrent infection, diabetics, people with multiple heath problems) need antibiotics that are active in tissues as well as the urine, e.g. amoxycillin/clavulanate, cephalexin, norfloxacin