What phenotype is related to 1. erm 2. met

1. target site modification 2. efflux pump

Review Cards Flashcards by Bryn Longcroft-Harris

3 UTI pathogens that give a positive Urease Test

Proteus
Morganella
Providencia

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What does Proteus look like on a SBA plate?

Swarming

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Why is Proteus the ideal UTI pathogen?

Breaks down urease!

This causes an increase in pH, crystal deposition, struvite stone formation, obstructive flow, and biofilm formation

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Enterococcus spp resistant to Vanco but sensitive to Teico. What is it?

VanB

Want to know the species though, if its faecium or faecalis it’ll be worse then if its gallinarum or cassiflavus

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How do you test for MRSA heterogenous resistance

Add NaCl to put the organism under osmotic stress which will induce the resistance
Cefoxitin best inducer
Put down a heavy inoculum because the resistance is rare

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Main way to differentiate strep from enterococcus

PYR test (enterococcus is positive)

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How to figure out what species of enterococcus you have

Motility (90% of gallinarum is motile, so only useful if you do see motility)
Pigment (cassiflavus is yellow on a white cotton swab)
Glucopyranoside test (gallinarum and cassiflavus are positive)

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2 pathogens that are most likely involved in a hip replacement infection

Staph aureus

Coag negative staph (longer lag period)

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16S PCR

Ribosomes have conserved and variable regions
Primers for conserved regions (will tell you if you have a bacteria or not)
Variable regions will tell you what organism it is

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3 problems with 16S PCR

Has to come from a sterile site
Easily contaminated
Has to be a monomicrobial infection

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Why is P. falciparum worse than the others?

There are way more parasites!

And they can infect any red cell regardless of how mature they are

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Factors/variables that can affect the types and sizes or zones seen using Kirby-Bauer disk diffusion?

Thickness of media
Temperature of incubation
Inoculum size
pH
Inoculum density
Potency of the disk
Disk spacing
Incubation time
Timing of disc application
Reading of the disc

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What phenotype is related to

target site modification

2. efflux pump

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What factors help improve the recovery of pathogens from the blood and/or minimize the risk of reporting a contaminant

Let the first few mLs drain to remove the skin plug
Take multiple bottles for multiple veni-punctures
Adequate volume of blood (more than 30mL)
Grow at least one bottle anaerobically
Have appropriate dilution between blood and media

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3 organisms dependent on capsule formation

Haemophilus influenza
Strep pneumonia
Neisseria meningitis

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What is a big risk factor for infection by encapsulated organisms?

Being asplenic!!

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CAMP test is positive for…

Listeria and group B strep

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What are some anti-pseudomonal antibiotics?

Piperacillin
Ciprofloxacin
Cefazitime
Tobramycin
Carbapenems

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Stenotrophominas maltophilia is susceptible to…

Septra

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2 common bacterial causes of otitis media

Strep pneumonia

Haemophilus influenzae

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Throat swab from 5 year old, grows on blood agar – small gram negative coccobacilli, ox and catalase +, oxidizes glucose and maltose
What is it and what do you do

Neisseria meningitis

DO NOTHING! Dont even mention it

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What is an acid fast stain look for and how does it work?

Looks for mycobacteria

Mycolic acid will retain the dye, even in the presence of a harsh acid

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Most common STI worldwide

Study These Flashcards

HPV

then herpes

How do bacteria become resistant to the quinolones

Study These Flashcards

Point mutations in the A subunits of DNA gyrase and Topo 4 to reduce the affinity of the drug for them
Also efflux pumps and down regulation of porin channels

Large gram + bacilli is likely...

Bacillus or Clostridium | Differentiate based on aerobic (B) or anaerobic (C)

Purpose of transport media

Maintain viability but do not allow growth

3 organisms that rarely represent true bacteremia

Corynebacterium Bacillus Propionibacterium

What do you treat for cat bites?

Amoxicillin and clavulanic acid | Because you can't use an oral cephalosporin and you get oral anaerobes in there that produce beta lactamases

Viruses that cause CNS infections (4)

HSV Rabies Enterovirus Arbovirus

Bloodborne viruses (3)

HIV HCV HBV

Viral exanthem viruses (6)

``` measles rubella roseola parvovirus B19 enterovirus varicella ```

Sexually transmitted viruses (3)

herpes molluscum contagiousum herpes

Respiratory viruses (7)

``` rhinovirus coronavirus enterovirus respiratory syncytial virus parainfluenza virus adenovirus influenza ```

GI viruses (5)

``` norovirus rotavirus astrovirus enteric adenovirus hepatitis A and E ```

Rheumatoid factor

IgM that binds the Fc portion of IgG Interferes with IgG assays Causes false positives/negatives

How is HIV/HCV/HBV detected?

Serology Start with a sensitive screening assay (overly sensitive) Need a confirmation assay that is highly specific Two tiered testing!!

HIV Diagnosis

1. 4th generation EIA 2. If negative, repeat over time 3. If positive, confirm with a Western Blot or Immunoblot 4. If Immunoblot is problematic, confirm with PCR 5. Monitor viral loads with real time/quatitative PCR

How are influenza symptoms different from other respiratory viruses?

``` Fever Muscle pain Malaise No runny nose or sore throat Cough Headache Fatigue, Weakness ```

Viral latency

Remains in DRG or trigeminal nerve and can reactivate at a later time

2 viruses that can remain latent

Herpes | Varicella Zoster Virus

Consequences of reactivation

``` Zoster Cold sores Genital/oral herpes Shingles Encephalitis ```

Pathogenesis of herpes

Primary exposure or reactivation

What type of CNS infection does herpes cause?

Encephalitis

Virus families with bats as the host

Bunyaviruses | Filoviruses

How do you test for measles

RT PCR from NP, throat or urine samples | Could also do serology

4 VHF families and an example of each

Arenaviridae (Lassa Fever) Filoviridae (Ebola) Flaviviridae (Dengue) Bunyaviridae (Hanta virus)

Best way to diagnose spirochetes

Serology! Lyme needs a 2 tiered testing Leptospirosis can do PCR from stool or urine early enough Syphilis needs treponemal and non treponemal testing

RPR for syphilis

Rapid Plasma Reagin Non-treponemal test Easy to monitor disease Used world wide

``` What is a 1. Bacteria 2. Virus 3. Toxin used for bioterrorism ```

1. Yersinia pestis, Bacillus anthracis, Francisella tularensis 2. Smallpox (Variola virus) 3. Botulism toxin

Methods of viral transmission (11)

``` Aerosol Droplet Contact Fomites Fecal oral Food or water borne Vertical Sexual Zoonotic Vectors Parenteral ```

Vector borne viruses (4)

Franciscella tularensis Borrelia burdoferi Rickettsia spp Orientia tsutsugamushi

Zoonoses viruses (3)

Rabies Ebola Influenza

Vaccine preventable diseases (likely to be on exam) | 8

``` Hep A/B MMR Varicella Yellow fever and JEV Smallpox Influenza HPV Rotavirus ```

Viruses where antiviral treatments are available (5)

``` Herpes HCV and HBV Varicella zoster HIV Influenza ```

If you forgot to take a CSF sample when someone has bacterial meningitis and you're already treating them, what test would you do to see what bacteria they have?

16S RNA PCR | Helpful to detect outbreaks

How does C diff causes disease?

``` Ingest spores Survive through gut Activated by bile salts Colonize mucosa Mucosal disturbance Grow and produce toxin Get disease ```

2 ways to detect outbreaks

1. Pulsed field gel electrophoresis (to get a fingerprint and then compare with the outbreak strains) 2. Sequence the whole genome

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