10 Control of multi-resistant microorganisms

Question 1

What are the mechanisms of antibiotic resistance?

Answer 1

◆ Destruction or inactivation of antibiotics, e.g. beta-lactam antibiotics, chloramphenicol,
and aminoglycosides.
◆ An alteration of antibiotic target site to reduce/eliminate binding of the antibiotic to
the target, e.g. beta-lactam antibiotics, fusidic acid, glycopeptides, erythromycin.
◆ Impaired uptake of the antibiotic either due to reduction in the cell permeability or
blockage of the mechanism by which the antibiotic enters the cell, e.g. beta-lactam
antibiotics, chloramphenicol, and quinolones.
◆ Enhanced efflux of the antibiotic, e.g. tetracycline.
◆ Acquisition of a replacement for metabolites step inhibited by antibiotic, e.g. trimethoprim
and sulphonamides.

Question 2

What is the importance of controlling multi-drug resistant organisms?

Answer 2

◆ The patient is less likely to respond to the first-line empirical antibiotic therapy.
◆ Restriction of use of narrow-spectrum agents which has a lesser incidence of
C. difficle infections.
◆ L imited choice in selection of older ‘tried and tested ‘agents which are cheaper and
their efficacy and side effect profiles are well known.
◆ Use of more expensive, newer agents with increasing cost. In addition, newer
agents have restricted licensing conditions due to limited availability of clinical
data on their efficacy and side effect profiles.
◆ Patients may have to stay longer in the hospital as some preparations are available
only in IV formulation and some MDROs have higher morbidity.
◆ I ncreased costs of isolation precautions and cost of additional investigations due to
extra length of stay.

Question 3

What are risk factors for multi-drug resistant organisms?

Answer 3

◆ Use of broad-spectrum antibiotics (esp. second- and third-generation cephalosporins
and quinolones). Treatment with previous glycopeptide (e.g. vancomycin,
teicoplanin) in VRE patients.
◆ P atients with severe underlying disease and who are chronically debilitated.
◆ Immmunocompromised and patients with extensive burns.
◆ Critically ill patients with prolong hospital stay, especially in ICU, oncology,
transplant, and burns wards.
◆ Presence with indwelling devices, e.g. IV lines, urinary catheters, endotracheal
intubation, surgical drains, PEG tubes, gastrostomy, and jejunostomy tube.
◆ Patients who have intra-abdominal, cardiothoracic, orthopaedic, vascular, and
urological procedures/surgery.
◆ Contact with health care facilities (hospital or community long-term care facility)
where MRDO is endemic and patients have spent more than 12 continuous hours
in the past 12 months (PIDAC guideline, 2007).

Question 4

What are infection control strategies for multi-drug resistant organisms

Answer 4

◆ Patient’s placement: the patient should be nursed in a single room with en suite
toilet facilities, if possible. If the isolation facilities are not available the patients
should be risk assessed and can be cohorted into bay/area. S/he should be
advised that there is no risk to healthy relatives or others outside the hospital
and should be given a fact sheet. As a general rule, infected/colonized patients
should be seen towards the end of a ward round, if practical. The number of
staff caring for the patient should be kept to a minimum.
◆ Visitors: visitors must report to the nurse-in-charge before entering the room.
Number of visitors should be kept to a minimum and those who are susceptible
are probably best advised not to visit a patient. This must, however, be balanced
against the visitor’s and patient’s wish for contact.
◆ Hand hygiene: physically clean hands must be disinfected using an alcoholic
hand rub. Alternatively, wash hands with soap (or antiseptic chlorhexidine/
detergent) and water before and after contact with the patient or their immediate
environment.
◆ Personal protective equipment: single-use disposable gloves must be worn
when handling contaminated tissue, dressings, or linen. Hands must be washed
after removing gloves. Single-use disposable plastic aprons must be worn for
activities involving contact with the patient or his/her environment and should
be discarded into a clinical waste bag before leaving the room. Non-permeable
disposable gowns are required only for extensive physical contact with the
patient. Masks should be used for procedures that may generate staphylococcus
aerosols, e.g. sputum suction, chest physiotherapy, or procedures on patients with
an exfoliative skin condition, and when performing dressings on patients with
extensive burns or lesions.
◆ Decontamination of item/equipment: use dedicated equipment (e.g. stethoscope,
sphygmomanometer, thermometer, and tourniquet). Any reusable
disposal items must be disinfected/sterilized according to local policy.
◆ Clinical waste: all single-use items must be disposed of as clinical waste. Clinical
waste bags must be sealed before leaving the room.
◆ Laundry: used linen must be handled g ently at all times in order to prevent
excessive dispersal of MRSA in the environment; they should be processed as
‘infected linen ‘according to the local policy. All linen must be put into the
appropriate bag, sealed at the bedside, and removed directly to the dirty utility
area or to the collection point. As fabric in contact with the person colonized/
infected with MRSA/VRE can act as a source of infection, the following measures
should be adopted to minimize the bioburden:
● Bed linen must be changed daily.
● Undergarments and nightwear should be changed daily.