Microbiology Flashcards
Who is at risk of hep b, c and HIV?
Injecting drug users
What should you test as markers of ongoing or previous hep B infection?
hep B surface antigen (HBsAg) and core antibody (anti-HBc IgG)
What will provide evidence of previous hep B immunization?
Hepatitis B surface antibody (anti-HBs)
Marker of previous natural infection with hep B?
Anti-HBc
Groups who should be offered hep B vaccination?
Likely contact with infected individuals, likely contact with high-prevalence populations, likely contact with infected blood or blood products, people for whom HBV would be a severe health problem, individuals at occupational risk.
Basic first aid for needlestick injury?
Wash off splashes with soap and running water.
Encourage bleeding if skin broken
Wash out splashes from the eye using an eye-wash bottle or copious amounts of tap water.
Admin actions after needlestick injury?
Make a careful record of the source and nature of the contamination.
Report the accident to a superior.
Immediately contact occupational health.
Preventative measures to minimise risk of needle stick injuries?
Immunisation against hep B.
Needlesafe devices used as extensively as possible.
Training in appropriate methods of taking blood and disposing of sharps
Sharps bins should be widely available and used appropriately (not overfilled)
In hep B what does core IgM positivity indicate?
Recent infection
In hep B what does HBeAg positivity indicate?
Blood is highly infectious
Definition of SIRS?
SIRS = RR >20, HR >90, temp >38, WCC 12.
Definition of sepsis?
Sepsis = SIRS + evidence of infection
Severe sepsis definition?
Severe sepsis = organ dysfunction
Definition of septic shock?
Septic shock = persistent hypotension despite adequate fluid resuscitation.
Commonest causes of surgical site infections following a ‘clean procedure’?
Staph aureus and Strep pyogenes
What is strep pyogenes?
Group A B-haemolytic streptococcus
Rarer causes of wound infection?
Anaerobic organisms (e.g. Bacteriodes spp, clostridium spp) and group B B-haemolytic streptococci
Appropriate first line abx for surgical site infection?
IV flucloxacillin - covers both streptococci and methicillin sensitive s.aureus
Appropriate abx regimen for Meticillin-sensitive Staph. Aureus?
Flucloxacillin. If penicillin allergic, clindamycin, clarithromycin or vancomycin (glycopeptide). Clindamycin avoided in >65 because of CDI risk.
Appropriate abx regimen for streptococcus pyogenes?
Benzylpenicillin, with oral switch to phenoxymethylpenicillin or amoxicillin. If penicllin allergic, options include clarithromycin, clindamycin and vancomycin.
Appropriate abx regimen for MRSA?
Vancomycin, with oral switch to e.g. clarithromycin, tetracycline or linezolid
Most likely organism for PVE?
Coagulase negative Staphlycoccus (CNS) = predominant cause of early onset PVE. Viridans streptococci (usual cause of native valve infective endocarditis) = main cause of late onset PVE.
Usual treatment of CNS PVE?
Usual treatment of CNS PVE would be comination of vancomycin and rifampicin for 6-8 weeks, with gentamicin for first two weeks.
Why do coagulase negative staphylococci infect prosthetic valves?
- Coagulase-negative staphylococci produce an exopolysaccharide (slime) which mediates adhesion, both to other organisms and to inanimate (plastic) surfaces).
