Med Micro Flashcards
0
Q
Factors doctors should take into account when choosing antibiotics
A
- site of infection
- toxicity of agent
- age of patient
- organism commonly causing infection
- if antibiotic is avail as an oral formulation
- cost of agent
1
Q
Most common cause of UTIs
A
Escherichia coli
2
Q
Why women more likely to develop cystitis
A
Women have shorter urethral and so easier for organisms to ascend the urinary tract to the bladder
3
Q
Pathogenesis of UTI in enlarged prostate
A
- difficulty emptying bladder
- residual urine is good culture medium for any organisms that have ascended the urethra
4
Q
Causes of sterile pyuria
A
- renal TB
- urethritis (gonococcal or chlamydial)
- use of antibiotics prior to urine collection
5
Q
Potential complications of a UTI
A
- recurrent infection
- renal damage and subsequent renal dysfunction
- hypertension
- renal abscess/ perinephric abscess
6
Q
Difference between sterilization and disinfection
A
- sterilization implies killing of all micro organisms
- disinfection is removal of most vegetative organisms except spores
7
Q
Sterilization methods
A
- filtration
- heat
- chemicals
- irradiation
8
Q
Method commonly used to sterilize in hospitals
A
- autoclaving
- cheap
- effective
- non-toxic
- not suitable for heat sensitive items
9
Q
Antibiotic to treat pneumonia
A
Should always include antibiotic with action against strep pneumoniae
- penicillin
10
Q
Significance of finding gram positive cocci in clusters
A
Indicates staphylococcus
- s aureus is pathogenic and would require specific antibiotic therapy
- could be coagulase negative staph which is probably a contaminant and therefore has no significance
11
Q
Tests to diagnose malaria
A
Blood smears
Antigen detection
12
Q
Clinical presentation of cystitis
A
- dysuria
- frequency
- urgency
- mild lower abdo pain
13
Q
Clinical presentation of pyelonephritis
A
All the same as cystitis and signs of systemic infection (fever)
14
Q
Conditions predisposing to UTI
A
- bladder tumour
- stones
- loss of neurological control of bladder
- diabetes
- catheterization
15
Q
Transmission of TB
A
Airborne route
- infectious particles remain airborne for hours and can circulate in air currents
- can infect people far removed from infectious patient
16
Q
Measures to limit TB spread in hospitals
A
- rapid identification of TB suspects and separate waiting areas
- adequate ventilation in waiting areas
- isolation of patients with pulm TB in side wards
- encourage cough etiquette
- wearing if appropriate masks
- masks for patients in public areas
17
Q
Complications of malaria
A
- cerebral malaria
- acute tubular necrosis
- pulmonary oedema
- jaundice
- GIT haemorrhage
18
Q
How malaria is transmitted
A
- by bite of anopheles mosquito
- blood transfusions
- sharing of needles
19
Q
Measures to prevent malaria
A
- chemoprophylaxis (mefloquine)
- prevention of bites (bed nets, insect repellant)
20
Q
Organisms that are not gram negative that could cause UTIs in patient with I dwelling urinary catheter
A
- coagulase negative staph
- yeasts
21
Q
Risk factors for getting UTIs
A
- females - short urethra
- sexual intercourse (mech factor promoting bacteria in urethra)
- pregnancy, large prostate, calculi (incomplete emptying, residual volume, stasis of urine)
- neurological problems (incomplete emptying of bladder)
- anatomical abnormalities (reflux or urine up ureters)
22
Q
Procedure for collecting urine sample from patient with in dwelling catheter
A
- milk catheter tube to push urine in tubing into bag
- clamp catheter just below collection port until 5-10ml collected above clamp
- clean the collection port with alcohol
- aspirate urine through collection port with syringe
- unclamp catheter
23
Q
Primary infections caused by strep pyogenes
A
- pharyngitis
- impetigo
- erysipelas
- cellulitis
- necrotising fasciitis
- scarlet fever
- puerperal sepsis/ wound sepsis
24
Things to expect on urine sample of patient with UTI
- numerous white cells/ polymorphs indicating infection
| - scanty/ no epithelial cells indicating a well taken sample
25
Appearance of strep pyogenes
Gram positive cocci in chains
26
Significance of epi cells in urine sample
- probably come from vaginal epi
| - suggest poorly taken sample
27
Instructions for patients when collecting a urine sample
- clean perineal area with soap and water
- collect midstream sample
- collect specimen into sterile container
28
Methods of collecting urine from infants
- urine bag specimen
- in-out catheter
- supra public aspirate (best quality)
29
Antibiotics useful as empiric therapy in UTIs
- co amoxiclav
- ciprofloxacin
- oral cephalosporin
30
Why BCG given?
To reduce the risk of serious childhood TB (meningitis and miliary)
- doesn't protect well against pulm TB
31
Possible aetiologies of UTIs
- ascending from urethra
| - haematogenous spread to kidney
32
Organisms thatcommonly cause community acquired UTIs
- E. coli
- staph saprophyticus
- proteus spp
33
Organisms that commonly cause hospital acquired UTIs
- E. coli
- p. Aeruginosa
- klebsiella
- yeast
- parasites - schistosomiasis
34
Empiric treatment of acute uncomplicated UTIs
1 dose of quinolone
35
Empiric treatment of complicated lower UTIs
```
Oral
- Co-amoxiclav
- cephalosporin
- quinolone
IV
- gentamicin
- cephalosporin
(5-7 days)
Lower = (10-14 days)
```
36
Prevention of UTIs
- avoid catheters
- empty bladder regularly
- long courses of antibiotics to prevent recurring infection in susceptible women
37
4 types of plasmodium
- falciparum
- ovale
- vivax
- malariae
38
Receptor for P falciparum
Universally present protein of ABO blood group
39
Lysis of RBCS in malaria causes
- fever
- anaemia
- reticulocytosis
- increased liver enzymes
- pigmentation
- hypertrophy of RES
- haemoglobinuria
40
Clinical presentation of malaria infection
- cold stage
- hot stage
- sweating stage
- apparent recovery
41
Tests for malaria
- blood smears (giemsa)
- rapid diagnostic tests
- serology
42
Chemoprophylaxis given for malaria
- mefloquine
43
Treatment for p falciparum
Coartem
44
Treatment for schistosomiasis
Praziquantel
45
Enzymes, haemolysins and toxins in strep pyogenes
- streptokinase
- DNAases
- streptolysin O
- erythrogenic toxin
46
Suppurative complications of strep pyogenes infection
- peritonsillar abscess
- otitis media
- sinusitis
- arthritis
- endocarditis
- osteomyelitis
47
Why is malaria important?
- many deaths
- affects healthy people
- being spread by modern travel
- often a diagnostic dilemma
- emergence of resistant strains
- mosquitoes are becoming resistant to insecticides
48
What P falciparum looks like under microscope
- commonly multiple rings in 1 red cell
- May be marginated
- double chromatin dot
49
Antigens of enterobacteria
O - outer membrane
K - capsular
H - flagella
50
Mechanisms of antibiotic resistance
- destruction or modification of antibiotic
- modification of target site
- pumps and pores
51
Action of B lactams
- target penicillin binding proteins that are involved in wall synthesis
- disrupt wall synthesis
52
Action of B lactamase
- destroy antibiotics
53
Why is strep can be resistant to penicillin
- alters PBP
| - clavulanic acid doesn't work because not Blactamase mediated resistance
54
Class of schistosoma
Trematoda
55
Life cycle of schistosoma
- eggs
- miracidia
- sporocytes
- cercaria
- schistosomulae
- worms
56
Pathology of schistosoma
- most related to host immune response to egg antigen
- cercaria cause HS reaction in skin
- schistosomulae cause sweating, urticaria and eiosinophilic infiltrate
57
Types of schistosoma
- mansoni (bowel)
| - haematobium (bladder)
58
Pathogenesis of s mansoni
- eggs in caps of intestine
- inflam response leads to fibrosis and thickening of intestine wall
- some eggs reach liver (portal HT, splenomegaly)
- some eggs reach lungs (pulm HT)
59
Pathology of a haematobium
- eggs in venous plexus of bladder
- acute haemorrhagic cystitis
- eggs calcify and fibrosis
- obstruction of ureters
- hydronephrosis
- secondary infection
60
Explain katayama syndrome
- acute allergic response to large amounts of schistosoma egg antigen
- onset 4-8 weeks post infection
- fever, headache,malaise
61
Classes of antibiotics
- inhibitors of call wall biosynthesis
- modifiers of cell membrane function
- inhibitors of protein synthesis
- inhibitors of nucleic acid biosynthesis
- miscellaneous
