Nosocomial

Nosocomial Infections Ghada

Outline  Definition  Most common types of infections  Responsible pathogens  Transmission of pathogens  Risk factors/Causes of infection  US mortality/morbidity data  Control measures/Treatment

What is a nosocomial infection?  Illness acquired in a medical setting in the course of medical treatment

 Major problem in hospitals and long term care facilities

 Most hospital cases found in ICU

 Infection is not present when admitted to the hospital

 Often is caused by an antibiotic resistant strain of microbe

 Estimated 5 – 10% rate of infection

Nosocomial vs. iatrogenic  Iatrogenic infection is a physician induced infection

 The term iatrogenic tends to blame the physician while nosocomial blames the hospitalization

 Often refer to the same infections

4 Major Types of Infections  1 – Blood stream infections  2 – Pneumonia  3 – Urinary tract infection  4 – Surgical site infection

Blood stream infections  Most important pathogen  coagulase negative staphylococcus – 39.3%

 10 – 15% of patients with a nosocomial infection have a BSI  

15% mortality rate Up to 45,000 deaths/year

 Coagulase negative staphylococcus  Found among normal flora of human skin and mucous membranes  Because most infections are nosocomial, C.N. staph. are increasingly antibiotic resistant

 Sutures often used to hold catheters in place are a major culprit

 Needle sticks may offer a path of entry for the microbes

Rash often associated with bacteremia or bacteria in the blood

Pneumonia  Most important pathogens  

Staphylococcus aureus – 16.8% Pseudomonas aeruginosa – 16.1%

 10 – 15% of patients with a noscomial infection get pneumonia  20 – 50% mortality rate

 Staphylococcus aureus is found among the normal flora of human skin and mucous membranes  Body usually keeps infection localized at the break point  Most hospital strains are antibiotic resistant

 Intubation and mechanical ventilation increase the risk of pneumonia by s. aureus

 P. aeruginosa is an opportunistic pathogen  Exploits breaks in host defenses to cause infection

 Famous for its resistance to antibiotics

Fluid in the lungs  Pneumonia usually caused by aspiration of bacteria clusters found in respiratory tract or upper GI tract

The problem with ventilators

Urinary tract infection  Most important pathogens  

Escherichia coli – 18.2% Candida albicans – 15.3%

 Up to 40% of patients with a nosocomial infection get a UTI

 E. coli is a natural inhabitant of the GI tract  Tests have shown that it is commonly found near the anterior urethra

 Candida albicans is a natural inhabitant of the GI and genital tract

 Normal urination clears the urethra of harmful

microbes while catheterization may allow microbes to colonize and infect the urinary tract

The UTI culprit

Surgical site infection  Most important pathogens  

Enterococci spp. – 14.5% coagulase negative staphylococcus – 13.5%

 Up to 54% of patients with a nosocomial infection who have also had surgery get a SSI  500,000 infections/year

 Enterococci spp. are a natural inhabitant of the GI tract

 Urinary catheterizations and antimicrobial use during hospital stays increases risk of infection

Infection following minimally invasive valve surgery

Risk Factors  Age  Immunodeficiency  Surgery  Medications – especially antibiotics  Chemotherapy  Extended hospital stays

3 Major players in nosocomial infections  1 – Antimicrobial use in hospitals and long-term care facilities

 2 – Failure of hospital personnel to follow basic infection control

 3 – Hospital patients are increasingly immunocompromised

 1 – Antimicrobial use has

produced resistant strains that are often found colonizing health care workers  These strains can be transferred to patients by normal human contact  Medical devices such as catheters and sutures offer a portal of entry for the microbes

 2 – Basic infection control  Handwashing  Wash hands after gloves are removed  Wash hands between patient contacts  Wash hands between different tasks on same patient to reduce cross contamination

 Gloving  Wear gloves when in contact with patient  Remove promptly after use  Avoid touching non-contaminated surfaces or objects

 Masking  Protect mucous membranes of the eyes, nose and mouth

 Gowning  Protect skin and clothes  Appropriate device handling  Avoid contamination with patient care devices  Appropriate handling of laundry  Prevent exposure to skin and mucous membranes  Prevent contamination of non-contaminated surfaces or objects

 3 – Immunocompromised patients  Due to increasing out-patient surgery the hospital is becoming a giant ICU  Only the sicker patients are admitted for substantial lengths of time

US Morbidity/Mortality  Blood stream infections  300,000 infections annually  45,000 deaths

 Pneumonia  300,000 infections annually  Up to 150,000 deaths

 Urinary tract infection  

Up to 800,000 cases per year Generally not fatal

 Surgical site infection  

27 million surgeries each year 500,000 infections per year

 At least 2 million nosocomial infections annually in the US

Control Measures  1 – Improve national surveillance  2 – Ensure surveillance is valid  3 – Improve design of invasive devices  4 – Aggressive antibiotic control programs  5 – New microbiological methods  6 – Basic infection control

 Surveillance  Improve in order to gain more representative data  Develop systems for use outside of the hospital

 Invasive devices  

Non-invasive monitoring devices Minimizing invasion of body during surgery

 Antibiotic control methods  Immunization  Non-pathogenic competing flora

 Microbiological methods  Pulsed-field gel electrophoresis  Analysis of microbe’s genetic material

 Basic infection control  Methods previously discussed

Treatment  Vancomycin – Drug of last resort  Some strains of staph. are resistant to all antibiotics except vancomycin  Disrupts synthesis of cell walls in gram positive bacteria  Only treatment for enterococcus infection  25% + of patients have a VRE infection  Average cost is $18,000

 Vancomycin;  Our last resort?

 Avoid unnecessary use of antibiotics  Complete prescribed dosage of antibiotics  If antibiotics don’t work:  Wait it out – hopefully the immune system will take care of things  Longer hospital stays  Increase mortality rates

 Any questions?