Bacterial Diseases Flashcards
Signs/symptoms of Infection by Escherichia coli
- Tiredness, Shaking, Chills, Pain in loin, Burning sensation when peeing
- Pale, suprapubic tenderness
- Positive nitrite, pus cells and protein
Pyelonephritis
inflammation of the kidney
-commonly caused by bacterial infection spread up urinary tract or travelled through the bloodstream
Uropathogenic E. coli major cause
UTI in anatomically normal, unobstructed urinary tracts
E. coli
motile, nonsporing gram negative bacillus with a typical bacterial cell wall of LPS
What kind of flagella does E. coli have?
Peritrichous flagella
-posess fimbrias important in adhesion
Agents that cause UTI
- Enterococci
- Enterobacteriacceae
Structure of E. coli lipopolysaccharide (LPS)
-lipid containing beta-hydroxy fatty acids attached to carbohydrate, core carbohydrate component consisting of monomers of different carbohydrates
Infection by Escherichia coli
entry into body, spread within body, spread from person to person
Why is female generally more likely to have a UTI compared to male?
Length of the urethra
In adulthood, up to ______ of females will have a urinary tract infection at some time in their lives
40%
Why is lack of estrogen risk factor for UTI in post-menopausal women?
microbial flora changes from one mainly of lactobacilli (Gram +) to one with gram -
What is a significant risk factor in hospitals for both males and females for UTI?
Catheterization
UTI clinical presentation in neonates
nonspecific with vomiting and fever
UTI clinical presentation in older children and adults
Cystitis ( inflammation of urinary bladder)
Dysuria (painful or difficult urination)
Suprapubic pain and fever
Hematuria (blood in urine)
UTI clinical presentation in elderly patients
Typical picture of fever, incontinence, dementia or signs suggestive of chest infection
UTI complications
renal scarring, septicemia, papillary necrosis, parenchymal abscess and perinephric abscess
UTI diagnosis
- culturing mid-stream specimen of urine
- number of bacteria in urine greater than 10^5 CFU/ml
UTI related cystitis treated with
3 days of ATB
- Ciprofloxacin (Cipro)
- Trimethoprim-sulfamethoxazole (Bactrim)
- Amoxycillin
Mac Conkey’s agar contains
carbohydrate Lactose
-allows differentiation onf Gram-negative bacteria
Mac Conkey’s agar
organisms which ferment Lactose (E. coli) produce acid-end products
-react with pH indicator and produce pink color
Infection by Clostridium difficlile signs
Chest infection, profuse watery diarrhea, abdominal pain
toxic megacolon
abnormal dilation of the colon that develops within a few days and can be life threatening
Beta-Lactam Antibiotics
Penicillins, Aztreoman, Cephalosporins, Carbapenems
Clostridium difficile
anaerobic spore-forming motile (gram + rod bacteria)
-pathogen produce toxins that can cause severe bloody diarrhea in patients treated with antibiotics
Clostridium difficile produces
- irregular (crenated edges) white colonies in blood agar
- is saccharolytic and produces three exotoxines ( TcdA, TcdB and binary toxin)
Toxin A and B induce
glycosylation of G-proteins and ultimately affect actin polymerization leading to loss of tissue integrity
Third toxin
binary toxin that has ADP ribosylating activity
-associated with increased virulence
Clostridium difficile entry into body
following ingestion of spores from contaminated feces or environment
- bacteria colonized mainly large intestine of GI tract
- commensal, normally doesn’t cause disease
Clostridium difficile diagnosis
detection of toxins in feces by ELISA and GDH (glutamate Dehydrogenase)
Psuedomembranous colitis diagnosed by
colonoscopy
-raised yellowish plaques may be seen on mucosa
Clostridium difficile treatment
First line: Vanomycin or metronidazole
Alternatives: Cholestryamine, Bacitracin-fuscidic acid/rifaximin, probiotic/fecal enema, intravenous immunoglobulin
Fecal Microbiota Transplantation (FMT)
fecal transplant for multiple recurrence
-used primarily to treat Clostridium difficile-associated infection