Infection prevention and control (IPC) is a practical, evidence-based approach which prevents patients and health workers from being harmed by avoidable infection and as a result of antimicrobial resistance.
No one should catch an infection while receiving health care, yet, these infections can spread through outbreaks and many regular care practices, affecting hundreds of millions of people across the world every year.
World Health Organisation
The Chain of Infection
A HAI (hospital acquired infection) occurs:
- up to 48 hours after hospital admission
- up to 3 days after discharge
- up to 30 days after an operation
RESERVOIR:
A microorganism lives and multiplies in what we call ‘reservoirs’: humans (eg. chickenpox, hepatitis B, and HIV), animals (eg. rabies, and salmonella), or inanimate objects (eg. tetanus).
INFECTION SOURCE:
This is the source of infection – a specific infection outbreak or an individual infection. An endogenous infection refers to an infection caused by the patient’s own microflora, while an exogenous infection refers to an infection caused through an environmental source. Zoonosis refers to an infection originating from an animal source.
ENTRY PORTALS:
- respiratory tract eg. pneumonia
- GI tract eg. Clostridioides difficile or C. difficile
- genito-urinary tract eg. CAUTI (catheter acquired urinary tract infection)
- skin breaks (including traumatic and surgical wounds)
- blood (through needles and catheters)
All patients are at risk of acquiring a MDRO (multi-drug resistant organism)!
TRANSMISSION ROUTES
- direct and indirect contact
- air
- food
- drink
- water
- insects
Direct or indirect contact include transmission via hands, transmission by inanimate objects, transmission by contact with blood, and transmission through sex…
Transmission via Hands:
- Staphylococcus aureus can be spread by staff, either through spreading their own nasal staph to their patients, or spreading staph from one patient to another.
- Gram-negative bacteria can be found colonising a patient’s skin, and then transmitted onto staff hands.
- Enteric Infections such as shigella and rotavirus (commonly found in children) are faecal-oral spreads transmitted via hands in the community and hospital setting.
Transmission via Inanimate Objects a.k.a. Fomites:
This type of transmission happens passively from one inanimate object to another. Objects include surgical instruments as well as more common objects such as pens, stethoscopes, books, suction catheters, bedpans etc.
Transmission via Sexual Contact:
Sexually transmitted diseases (STDs) are considered to be very fragile and so, they do not usually survive on inanimate objects. STDs include syphilis gonorrhoea, chlamydia, HIV, herpes, etc.
Transmission via Blood:
Transmission by contact with infected blood happens through wounds, menses, human bites, blood products, specimens, contaminated needles (including needle-stick injuries), and during traumatic sexual intercourse.
Endemic Hepatitis B is transmitted during birth from the mother to her baby. Other infections which can pass to the foetus during pregnancy includes rubella, cytomegalovirus and syphilis.
Transmission via Air a.k.a. Airborne Transmission
Transmission via air happens through sneezing, coughing and speaking. Small droplets (<0.1mm) evaporate; Solid droplet nuclei may remain airborne…these may be eventually inhaled. Measles, chickenpox and tuberculosis are spread in this way. Large droplets fall to the ground.
Transmission via Food, Drink, and Water:
Transmission of infection via food, drink and water usually happens in enteric infections via faecal-oral spread.
In food poisoning, bacteria multiply in food prior to ingestion, producing enteric toxin (eg. in staph aureus) or multiply and produce toxin in bowel lumen (eg. in cholera and E.coli). Salmonella happens through infection following ingestion of poorly-cooked food. Brucellosis is an infection resulting from drinking unpasteurised contaminated milk. In water-borne cholera, faecal excretion by-carriers contaminate river water which is then consumed downstream.
Transmission via Insects a.k.a Anthropod-borne Infections:
Anthropod-borne infections are transmitted by blood-sucking insects such as mosquitos (malaria). These parasites have the ability to multiply in their hosts.
The Infection Spectrum
Contamination => Colonisation => Critical Colonisation => Infection
Colonisation is the presence of multiplying bacteria with no reaction or symptoms.
Infection is the presence of multiplying bacteria which affects the host’s defenses, causing clinical symptoms.
Bacteria can be transmitted even if no infection is present. This explains why Staphylococcus aureus, which is endemic, can be found outside the hospital, within the community, undetected.
MRSA – Methicillin Resistant Staphylococcus Aureus
MRSA is resistant to common antibiotics such as penicillins and cephalosporins. MRSA can be carried around by healthy individuals without any symptoms for weeks to years.
MRSA in a patient with a low colonisation level may not be detected by culture. Anterior nares specimen testing result in the highest identification rate for MRSA. Gloves should be worn when caring for infected wounds of patients with MRSA.
Patients are screened for MRSA on admission and more importantly before important procedures.
Treatment for MRSA decolonisation:
- 2% Mupirocin (Bactroban) nasal ointment 3 times per day for 5 days (apply small amount to inner nostrils using tube, press nostrils together and massage for about 1 minute).
- Daily full body and hair washes with 4% chlorhexidine gluconate.
Isolation and Contact Precautions for Infection Prevention and Control
Isolation and contact precautions should be put in place in the case of current or previous 6 months colonisation or infection with MDRO. Contact precautions notice should be put up on the patient’s door, and related information should be provided for both the patient and relatives.
Contact precautions can be stopped:
- if the organism is not cultured again
- in case of 3 consecutive negative MRSA screen cultures
Terminal cleaning of patient’s room must be performed!
Infection Prevention and Control
5 Moments for Hand Hygiene
- BEFORE patient contact
- BEFORE aseptic task
- AFTER body fluid exposure
- AFTER patient contact
- AFTER leaving patient surrounding
- Soap & Water mechanically remove microorganisms and soil but DO NOT kill microorganisms; remove transient skin flora, but only limited resident flora.
- Alcohol Rub DOES NOT mechanically remove microorganisms or soil, but kills microorganisms; kills transient skin flora, but only limited resident flora.
- Aqueous Antiseptic Solutions mechanically remove and kill microorganisms and soil; remove and kill transient and some resident skin flora.
Standard Precautions for Infection Prevention and Control
Standard precautions should be applied by all staff in all healthcare settings to all patients regardless of diagnosis and infection status all the time.
- Good hand hygiene practice
- Use waterproof dressings to cover wounds or skin lesions
- Use cough etiquette
- Do not touch your eyes, nose, mouth or face, or adjust PPEs with contaminated hands or gloves
- Limit contact with patient’s items in immediate surrounding area to the minimum
- Use recommended PPEs for required tasks anticipating possible risks
Donning PPEs Sequence:
- Gown
- Mask
- Visor
- Gloves
Doffing PPEs Sequence:
- Gloves
- Visor
- Gown
- Mask
Swabbing Methods
Staphylococcus aureus produces a higher cultivation of bacteria in the nose and throat, thus swabbing methods used for MRSA are the nasal swab or the throat swab. Note however, that MRSA can also be found in other locations within the body, such as in wounds.
Nasal Swab
Throat Swab
Wound Swab
Urine Sampling
Sputum Sampling
Stool Sampling
Blood Cultures
Peripheral Vascular Catheter Care
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