Download Microbiology 2 – Hospital Acquired Infections

Microbiology 2 - Hospital Acquired Infections
Anil Chopra
1. Explain why patients in hospital are particularly at risk from acquiring new
infections.
2. Give examples of common hospital infections acquired by airborne
transmissionand by direct contact.
3. Account for the rise in infections due to MRSA.
There are 5 main antibiotic resistant infections in the UK:
- Pseudomonas aeruginosa
(gram –ve)
- Acinetobacter baumanii
(gram –ve)
- ESBL Enterobactaeciae
(gram –ve)
- MRSA
(gram +ve)
- Enterococcus faecium (gram +ve)
Antimicrobial: interferes with the growth and reproduction of a microbe.
Antibacterial: agents used to eliminate or reduce harmful bacteria.
Antibiotic: a type of antimicrobial drug used in humans and animals.
11% of inpatients in hospitals have a hospital acquired infection at any time. These
include:
- clostridium difficile – 3 800 p.a
- MRSA – 1629
They cause a huge burden on the NHS by increasing the length of stay for patients as
well as costing 100 million pounds.
Most discoveries of anti-biotics took
place between 1940 and 1990 and were
increasingly used which eventually lead
to their resistance.
MRSA – Multi-Resistant Staphylococcus aureus
The incidence of MRSA has increased dramatically in
recent years and a number of different species of
bacteria are becoming resistant to antibiotics.
The reason for the resistance development stems from
the frequency of mutation of the different bacteria –
bacterial reproduction times range from minutes to
hours. It is also attributed to the ability of bacteria to
transfer DNA horizontally:
NB: 10 times more antibiotics are used in agriculture than in medicine.
Reasons for High Rates
- Infections from lines:
o Intravenous
o Central
o Arterial
o CVP/Pulmonary artery
- Chemotherapy
- Catheterisation
- Prophylactic antibiotics
- Inappropriate prescribing
- Intubation
- Prosthetic material
- Dissemination from patient to patient via doctors
- Concentration of people on wards
Clinical Syndromes
Wound or line sepsis
- Skin flora
o S. aureus
o Coagulase negative Staph.
o Streptococcus spp.
- Enteric bacteria
o E. coli, Klebsiella
o Pseudomonas
o Enterococci
Nonsocomical pneumonia
- S. aureus
- Klebsiella
- Pseudomonas
Urinary tract infections
- E. coli, Klebsiella
- Pseudomonas
- Proteus mirabilis
- Enterococci/ S. aureus