Download Microbiology 3 – Control of Infection

Microbiology 3 - Control of Infection
Anil Chopra
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The importance of hospital acquired infection.
The bacteria & the infections they cause.
The role of the Infection Control Team.
The principles of prevention of hospital acquired infection - how to minimise the
risk of transmitting infection
Hospital acquired infections are a major problem, they not only can cause great
morbidity and mortality for patients but are also a huge financial burden on the NHS1 billion pounds a year as well as generating a lot of media interest. It is estimated
there are around 100 000 cases and 5 000 deaths a year.
The Bacteria
MRSA (methicillin resistant Staphylococcus aureus)
Differences between MRSA and MSSA (non-resistant Staphylococcus aureus):
» MRSA is harder to treat with normal anti-biotics
» Alternative treatments to MRSA may be toxic.
» Both are carried asymptomatically
» Both have the same pathogenicity – very serious.
VRE (vancomycin resistant enterococci) – generally a low-grade pathogen but
can cause harm in immunosuppressed patients.
Clostridium difficile
Resistant gram-negative rods e.g. Acinetobacter spp.; Klebsiella spp.;
Enterobacter spp. and many more.
Microbiology
Microbiology still relies on phenotypic methods of identification and sensitivity
testing however recently molecular methods are becoming increasingly available and
important:
- polymerise chain reactions
- GenProbe
- Usage in TB and Chlamydia
- Pan-bacterial primers
- Detecting the gene MecA (which causes resistance to flucloxacillin in MRSA)
Reasons for Infections
Debilitated – poor nutrition.
Surgery/trauma - wounds etc.
Immunosuppressed – chemotherapy; underlying illness; diabetes etc.
Antibiotic treatment – wipe out normal flora and allow colonisation and
infection with resistant strains.
Conditions Caused
Respiratory tract infection (RTI)
Urinary Tract infection (UTI)
Wound infection
C. difficile diarrhoea and colitis
Line sepsis
Implant sepsis - e.g. vascular graft; prosthetic joint etc.
Biofilm: a complex aggregation of microorganisms marked by the excretion of a
protective and adhesive matrix. They trascribe different genes from free living
bacteria. Examples include Candida albicans; CoNS; Enterococcus spp.; Klebsiella
spp., Pseudomonas aeruginosa; S. aureus.
Management
Send appropriate samples before starting antibiotics.
Blood cultures, MSU, sputum, wound swabs, etc.
What antibiotic???
IV or PO route?
Hospital antibiotic guidelines.
Check with Microbiology if unsure.