Hospital-Acquired Infections

• Key terms include MRSA, standard precautions, and biomedical waste
• Infections are considered hospital-acquired, if they are developed in hospitalized patients who were neither infected nor incubating the illness at the time of admission.

Sources of Hospital-Acquired Infections

• Exogenous sources include contact with other patients and staff, as well as environmental sources
• Endogenous sources, are the most common, and are considered self-inflicted

Factors Influencing Hospital-Acquired Infections

• Infants and elderly are more susceptible because of their poor immunity
• Pre-exisiting disease weakens immunity
• Contaminated catheters and other procedures increases infection risk
• Hospital bacteria are often multidrug-resistant, which can lead to infections
• Blood, blood products, and IV fluids may carry blood-borne pathogens

Microorganisms Causing Hospital-Acquired Infections

• Staphylococcus aureus are drug-resistant strains, specifically methicillin-resistant Staphylococcus aureus (MRSA)
• Pseudomonas spp. causes hospital-acquired pneumonia, UTIs, and burn wound infections, especially Pseudomonas aeruginosa
• Tetanus spores are present in improperly sterilized areas
• Viruses like HIV, Hepatitis B & C, and other viral infections can spread through contaminated blood or hospital environments
• Fungi and Parasites like Candida, Aspergillus, Mucor, Plasmodium spp. and Entamoeba histolytica can spread in hospitals

Routes of Transmission

• Contact is the most common transmission route
• Direct contact (person-to-person) can spread staphylococcal and streptococcal sepsis
• Indirect conduct through equipment spreads enterobacterial diarrhea and P. aeruginosa sepsis
• Airborne transmission includes
• Droplets inhaled from respiratory secretions
• Dust from bedding, floors, and wounds, spreads P. aeruginosa, S. aureus
• Aerosols from nebulizers and humidifiers spreads Legionella in water
• Transmission also occurs through
• Oral contamination of hospital food
• Parenteral inoculation from contaminated syringes and blood products
• Self-infection from the patient's own flora spreads, for example, Staphylococcus from skin infecting wounds

Common Hospital-Acquired Infections

• Urinary Tract Infections (UTI)
• Caused by urethral catheterization; common pathogens: E. coli, Pseudomonas, Staphylococci, Enterococci, Candia albicans.
• Respiratory Infections
• Due to invasive respiratory procedures; pathogens: Staphylococcus aureus, Klebsiella, Pseudomonas aeruginosa, Acinetobacter, Legionella, respiratory viruses.
• Wound & Skin Sepsis
• Common in post-op patients; pathogens: S. aureus, P. aeruginosa, Enterococci, Coagulase-negative Staphylococci
• Gastrointestinal Infections
• Hospital-acquired food poisoning; pathogens: Salmonella, Shigella sonnei.
• Burn Infections
• Caused by Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes.
• Bacteraemia & Septicaemia
• Linked to invasive procedures; common pathogens: Gram-negative bacilli, S. epidermidis (endocarditis risk in patients with artificial heart valves).

Role of Nurses in Prevention and Control of Infections

• Standard precautions are
• Practicing hand hygiene
• Wearing gloves
• Wearing facial protection (eyes, nose, mouth)
• Wearing gowns
• Preventing needle stick and injuries from sharp instruments
• Maintaining respiratory hygiene and cough etiquette
• Environmental cleaning
• Using clean linens
• Proper waste disposal
• Cleaning patient care equipment
• General Methods are
• Proper sterilization of instruments and equipments
• Cleaning and disinfection of hospital environment
• Skin disinfection and antiseptics before handling patients
• Rational antibiotic prophylaxis
• Protective clothing
• Isolation of susceptible patients
• Periodical monitoring and surveillance

Biomedical Waste (BMW)

• Waste generated during diagnosis, treatment, or immunization of humans or animals, research activities pertaining thereto, or in the production or testing of biologicals.

Types of Biomedical Waste

• Infectious Waste can transmit viral, bacterial, or parasitic diseases through human, animal, and laboratory waste
• Noninfectious Hazardous Waste poses a risk to human health

Categories of Biomedical Waste, Treatments, and Disposal

• Human anatomical waste incineration/deep burial
• Animal waste incineration/deep burial
• Microbiology and biotechnology waste local autoclaving/microwaving/incineration
• Waste sharps disinfection/autoclaving/shredding
• Discarded medicines and cytotoxic drugs incineration/destruction and drugs disposal in secured landfills
• Solid waste contaminated with blood and body fluids incineration, autoclaving/microwaving
• Solid waste generated from disposable items disinfection/autoclaving/shredding
• Liquid waste disinfection by chemical treatment and discharge into drain
• Incineration ash disposal in municipal landfill
• Chemical waste chemical treatment and discharge into drain for liquid and secured landfill for solids

Waste Segregation

• Yellow plastic bag waste contains: human, animal and microbiology waste and is treated by incineration/deep burial
• Red disinfected container/plastic bag contains: microbiology and solid waste and is treated by autoclaving/microwaving/chemical treatment
• Blue/white translucent puncture proof container contains: waste sharps and solid waste and is treated by autoclaving/microwaving/chemical treatment and destruction shredding
• Black plastic bag contains: discarded medicines, incineration ash, and chemical solid waste and is treated y disposal in secured landfill

Treatment and Disposal Technologies for Health Care Wastes

• Waste Treatment methods include,
• Incineration to burn infectious waste into ashes is effective but expensive
• Autoclaving uses 121°C steam for 60 min to sterilize infectious waste
• Chemical Disinfection uses chemicals (e.g., hypochlorite) for liquid waste treatment
• Microwave Irradiation heats water in waste using microwaves (2450 MHz) to kill the microbes

Thermal Treatment as a method of Waste Treatment

• Wet treatment involves steam disinfection of infectious waste
• Dry treatment shreds and heats waste, reducing volume by 80% and weight by 20-35%
• Inertization mixes waste with cement to prevent contaminations of water sources

Waste Disposal

• Includes landfilling, deep burial, sewage disposal, and incineration