Nosocomial Infections - Applied Microbiology - Lecture Slides, Slides of Microbiology

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Nosocomial

Infections

Hassan

Rasouli

Nosocomial

Problems

Problems

with

Healthcare

Associated

Infections

“…hundreds of millions of patients around the world are affected by healthcare

associated infections every year and that an estimated

to

percent of patients admitted to modern hospitals in the developed world acquire one or more infections”

The World Health Organization

Sources

of

microbial

Agents

Before basic hygienic practices and antibiotics ‐ hospital infections were due to pathogens of external origin, not normal microbial flora

Most are now opportunistic microorganisms common in general populations - E.g. Staphylococcus aureus

Microbial

Reservoirs

and

Transmission

Permanent and transient flora of patient - Normal flora transmitted through damaged tissue, outside of normal tissue reservoir or inappropriate antibiotic therapy - Flora of other patient or staff member - Direct contact - Aerosols - Contaminated food or objects - Flora from healthcare environment - Endogenous or exogenous microbes - Water, damp areas, linen, equipment and supplies, fine dust and droplets in the air

Catheter

associated

Urinary

Tract

Infections

(CAUTI)

Number one most common nosocomial infection - At risk - More women than men - Immuno ‐ compromised patients - Catheter use - Patients with nerve damage around bladder - Infection caused by E. coli - Gram ‐ negative - Normal flora - E. coli 0157:H shiga ‐ producing toxin - Affects the Bladder, kidney, urethra

CAUTI:

Symptoms

and

Treatment

Symptoms:

Bladder infection: burning sensation while urinating, bloody urine, fatigue - Kidney infection: high fever, abdominal pain, chills - Treatment - Antibiotics for up to 2 weeks - Fluoroquinolones - Amoxicillin - Fluids

CDI:

Treatment

Options

Treatment - Halting antibiotic treatment - Metronidazole or vancomycin use - Surgery to remove infected part of intestine - Fecal bacteriotherapy - WHAT? - Fecal bacteriotherapy (Stool transplant) - Infusing intestinal microorganisms in suspension of healthy donor stool into intestine of a sick patient in attempt to return the normal microbial flora - Study: 317 patients treated across 27 case series - Results: highly effective - Disease resolution in 92% of cases

Surgical

Site

Infections

(SSI)

Common postoperative complication

14 ‐ 17% of all hospital ‐ acquired infections - 38% of hospital ‐ acquired infections in surgical patients - Gram positive species - Staphylococcus aureus - Streptococcus pyogenes - Enterococcus - Symptoms:^ • Purulent discharge abscess or spreading cellulitis at

Ventilator

associated

Pneumonia

(VAP)

of patients that have been on ventilator for over

days get

VAP

microbial causes:

Pseudomonas aeruginosa - Staphylococcus aureus - Enterobacteriaceae - Haemophilus influenzae - Streptococcus species e.g. S. pneumoniae

Ventilator

associated

Pneumonia

(VAP)

Symptoms

At least 2 of these symptoms: - Cough, purulent sputum, new infiltrate on chest radiograph consistent with infection - Treatment - Early onset: ceftriaxone, fluoroquinolones - Late ‐ onset: antipseudomonal cephalosporins, beta ‐ lactam inhibitors with antipseudomonal fluoroquinolone - High case mortality rate

Antibiotic

Resistance:

VRE

Vancomycin

resistant Enterococcus

Gram ‐ positive found in healthy intestines of mammals - Mutant strain that is resistant to vancomycin - Vancomycin: very strong antibiotic - used as last resort - Spread: fecal to oral route - Risk factor: cephalosporins

Nosocomial

infections:

Other

costs

Increased Morbidity and Mortality Rates

Economic Costs - Due to extended hospital stays, extra treatments, lab tests, medication, isolation, supplies, nursing and physician care, general maintenance ‐ $20, ‐ 25, per patient per year ‐ Total: $1. billion per year ‐ Importance of prevention