Sexually transmitted, congenital, and urinary tract infections Flashcards
Urinary system
Organs of the urinary system, consists of two kidneys, two ureters, a single urinary bladder and a single urethra. Urine passes through the ureters into the urinary bladder, where it is stored prior to elimination through the urethra. In the female, the urethra carries only urine to the exterior while in the male the urethra is a common tube for both urine and seminal fluid.
The bladder should be sterile
Cystitis = infection of the urinary tract Pyelonephritis = infection of the kidneys
E. coli gut flora is the cause of 80% of all community-acquired UTIs (Hospital acquired UTIs are different).
Female reproduction
Girls have two ovaries, two fallopian tubes, the uterus, including the cervix, the vagina and external genitals. The ovaries produce female sex hormones and ova. When an ovum is released during the process of ovulation, it enters a uterine/fallopian tube, where fertilisation may occur if viable sperm are present. The zygote descends the tube and enters the uterus. It implants in the inner wall of the uterus and remains there while it develops into an embryo and, later, a fetus.
Note the close proximity of the urethra to the vagina and the short length of the urethra which all predispose women to urinary tract infections.
Predominant bacteria in the vagina are the lactobacilii which produce lactic acid, which maintains the acidic pH (3.8-4.5) of the vagina, inhibiting growth of other bacteria. Other bacteria such as streptococci, various anaerobes, and some gram-negatives are also found in the vagina. Derangement of this careful balance of microbiota leads to bacterial vaginosis. Candida albicans is normal flora in some women and only causes trouble when it over-grows.
Male reproduction
The male reproductive system consist of 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 deferens, ejaculatory duct and urethra.
*Note the relative length of the male urethra compared to the female.
The male urethra is usually sterile, except for a few contaminating microbes near the external opening.
Analysis of Urine in the Laboratory
- GET A GOOD SPECIMEN: Midstream urine, should be bladder urine only (no menstrual blood, epithelial cells, bowel flora
- Observe colour, blood content, debris, unusual material
Perform a “dipstick” analysis:
glucose
ketone
specific gravity
blood
pH
nitrite – due to nitrate reduction by E. coli
leucocytes –an indication of infection - May perform microscopic examination
- Culture, incubate at 37C for 18 hours
- Examine, select “significant” isolate for identification
Perform antibiotic susceptibility tests
Trimethoprim
Trimethoprim is currently the drug of choice for the empirical treatment of uncomplicated UTIs.
300mg nocte 3 days.
It is vital to detect RESISTANCE
Microbial causes of UTI
Organism G P Hospital E. coli 75% 40% St. saprophyticus 7 6 Proteus sp 6 15 Klebsiella sp 3 12 Enterococcus 3 15 Pseudomonas 1 6 Enterobacter 1 3
*UTIs acquired in hospital tend to be caused by the more antibiotic-resistant organisms
Pyelonephritis – always do a urine culture
Pyelonephritis is a serious infection with risk of bacteraemia.
You must rely on evidence of UTI along with signs and symptoms suggesting upper UTI (fever, chills, flank pain, nausea, vomiting, costo-vertebral angle tenderness). Lower UTI symptoms may be absent.
Urine culture should always be performed
Perform dipstick analysis.
Antibiotics should be started before results are available
Urine culture is indicated in males
All UTIs in men are considered complicated
Urine culture should always be performed
Start Trimethoprim. Give for 7 days
Review the lab results when they are back
Prostatitis
Entry of micro-organisms into the prostate gland almost always occurs via the urethra.
The flora of acute prostatitis reflects the spectrum of agents causing genital infection or UTI.
Signs: fever, dysuria, pelvic or perineal pain, cloudy urine.
Urine culture is useful because growth of a urinary pathogen and antibiotic susceptibilities will guide treatment.
If urine culture is negative, STIs should be excluded (chlamydia and gonorrhoea)
Antibiotics (Cotrimoxazole) should be given before culture results are available.
Culture results may modify treatment.
Prostatic “massage” is not recommended. It is painful and may cause bacteraemia.
Screening in long term care facilities
Screening for UTIs is not recommended
Symptomatic UTI needs investigating
Keep a record of the results for the institution. There may be outbreak strains with unusual susceptibilities
Sterile pyuria – ie Leucs +++, no growth
Always consider a Sexually transmitted infection especially due to
Neisseria gonorrhoeae or Chlamydia trachomatis
What is The Clap?
Gonorrhoea is caused by Neisseria gonorrhoeae
Anaerobe, gram negative diplococci
Incidence <1% in NZ
Men = always symptomatic
Women = mostly asymptomatic
Can infect the pharynx, rectum and reproductive tract right up to PID and infertility
Very clever and very difficult to treat
Case Study:
Would you expect the girl and her boyfriend to have been successfully treated on the first occasion with Ceftriaxone?
Yes, it is the currently recommended empiric treatment for infection with Neisseria gonorrhoea. It is the last class of antibiotic left that the bacteria haven’t yet developed resistance to.
What course of action would you recommend on this second occasion, in terms of treatment and prevention of cross-infection?
The patient requires a new dose of Ceftriaxone, then to abstain from sexual intercourse for at least 7 days. Must use barrier protection to prevent further infection. Could also alert boyfriend’s other girlfriend that she is at risk of gonorrhoea infection and should be treated.
What advice would you give the girl regarding recurrent infections and the possible long-term effects of these on her body?
Scarring from repeated inflammation could lead to infertility. Ascending infection can cause PID and perihepatitis requiring hospitalisation. If she gets pregnant her baby may be born with gonorrhoeal eye and lung infections.
Congenital and Perinatal Infections
Microbes must cross the placenta to infect the foetus
Abortion or fetal damage
Rubella virus (congenital rubella syndrome)
Toxoplasma gondii (toxoplasmosis)
Cytomegalovirus (congenital CMV)
Treponema pallidum (congenital syphilis)
Listeria monocytogenes (congenital listeriosis)
Zika virus (microcephaly)
Perinatal infections are acquired at birth eg. HSV, CT, NG, GrpB Strep
Pre-term Delivery
What other microorganisms can cause premature delivery?
Chlamydia and gonorrhoea (STI)
Ureaplasma, Mycoplasma (STI)
Group B Streptococcus agalactiae (normal flora)
Brucella (zoonosis)
*“The reason the mother is more susceptible is not necessarily because her immune system is compromised, but because the bacteria that got into her placenta are infecting her,” said Anna Bakardjiev, the study’s lead author and a postdoctoral researcher with Daniel Portnoy, professor of biochemistry and molecular biology at UC Berkeley. “The miscarriages that result from these infections may be a natural defense mechanism to dispel this source of infection.”
