microbiology (role of drug resistant bacteria in hospital infections)

antimicrobial resistance

- ability of microbes, such as bacteria, viruses, parasites or fungi to grow in the presence of a chemical (drug) that would normally kill it or limit its growth

causes of drug resistance

1. selection of bacterial resistance
- microbes are either killed or survive in the presence of an antimicrobial
- the survived microbes will replicate and their progeny will quickly become the dominant type throughout the microbial population
2. mutation
- most microbes reproduce by dividing every hour to allow them to evolve rapidly and adapt quickly to the new environment
- mutation arise during replication and help an individual microbe survive exposure to an antimicrobial
3. gene transfer
- microbes also get genes from each other including genes that make them drug resistant
4. inappropriate use
- selection of resistant microorganisms is exacerbated (worsen) by inappropriate use of antimicrobials
- some healthcare providers will prescribe antimicrobials inappropriately, wishing to treat the patients with viral infection
5. inadequate diagnostics
- specific antibiotic can delay the emergence of broad-spectrum antimicrobial resistance
- the use of antibiotics in treatment of viral infections due to improper diagnosis accelerates the emergence of antimicrobial resistance
6. hospital use
- the extensive use of antimicrobials and close contact among sick patient creates a fertile environment for the spread of antimicrobial-resistant germs
7. agricultural use
- adding antibiotics to agricultural feed promotes drug resistance

important drug resistant bacteria

- vancomycin-resistant Enterococcus (VRE)
- Carbapenem-resistant Enterobacteriaceae (CRE)
- Multi-drug-resistant Mycobacterium tuberculosis (MDR-TB)

transmission of resistant organisms

- contact with the healthcare worker
- lack of hand hygiene, inadequate patient care techniques, contaminated supplies/equipment
- failure to implement contact precautions
- inadequate environmental care
- promoting of resistance through inappropriate antimicrobial therapy

factors increase the resistance

- unnecessary prescribing and overprescribing of antibiotics
- patients do not complete the course of any prescribed antibiotics
- neglecting hand-washing
- not following infection control procedures