Hospital acquired infections

Definition

Hospital-acquired infections (HAIs), also known as nosocomial infections, are infections that patients acquire during the course of receiving healthcare treatment for other conditions.
They are typically identified 48 hours or more after admission.
Common HAIs include infections of the bloodstream, urinary tract, surgical site, and respiratory tract.
HAIs are a significant cause of morbidity and mortality in healthcare settings.
Prevention and control of HAIs are critical components of healthcare quality and patient safety.

Epidemiology

Approximately 5-10% of hospitalized patients acquire an HAI.
HAIs are more common in intensive care units (ICUs).
Higher prevalence in elderly patients, those with comorbidities, and immunocompromised individuals.
Surgical site infections and urinary tract infections are among the most frequent HAIs.
Antibiotic-resistant organisms such as MRSA and C. difficile are significant contributors to HAIs.
Annual HAI incidence in the UK estimated to be around 300,000 cases.

Aetiology and pathophysiology

Caused by a variety of pathogens: bacteria, viruses, fungi, and parasites.
Common bacterial pathogens: Staphylococcus aureus (including MRSA), Escherichia coli, Pseudomonas aeruginosa.
Transmission can occur via direct contact, contaminated equipment, or healthcare workers’ hands.
Pathophysiology involves colonization followed by invasion of sterile body sites.
Biofilm formation on medical devices like catheters and implants contributes to chronic infections.
Risk factors include prolonged hospital stay, invasive procedures, and inappropriate antibiotic use.

Types

Symptoms

Fever, chills, and malaise are common non-specific symptoms.
CAUTI: dysuria, frequency, urgency, lower abdominal pain.
SSI: localized redness, swelling, warmth, purulent discharge.
CLABSI: signs of systemic infection, erythema, and tenderness at catheter site.
HAP/VAP: fever, purulent sputum, leukocytosis, new infiltrate on chest X-ray.
CDI: watery diarrhea, abdominal cramps, fever.
MRSA: skin and soft tissue infections, pneumonia, bloodstream infections.
Viral infections: symptoms specific to the virus, e.g., respiratory or gastrointestinal symptoms.

Signs

Elevated temperature (fever).
Tachycardia and hypotension in sepsis.
Localized erythema, warmth, swelling in SSIs.
Purulent drainage from wounds or catheter sites.
Abnormal breath sounds, hypoxia in VAP.
Diarrhoea and abdominal tenderness in CDI.
Rash, vesicles, or pustules in viral infections.
Positive blood cultures indicating bloodstream infection.
Radiological evidence of infection (e.g., chest X-ray showing infiltrates in pneumonia).
Lymphadenopathy in systemic infections.

Tests

Blood cultures: to identify bloodstream infections.
Urine cultures: for diagnosing CAUTI.
Wound swabs and cultures: for SSIs.
Sputum cultures and endotracheal aspirates: for VAP.
Stool tests: for diagnosing CDI, including toxin assays and PCR.
Imaging: chest X-ray, CT scan, or ultrasound depending on suspected infection site.
Antibiotic sensitivity testing: to guide appropriate antimicrobial therapy.
FBC, CRP, ESR: to assess the extent of infection and inflammation.
PCR and serology: for viral infections.
Regular monitoring of vital signs and clinical parameters.

Management

Empiric antibiotic therapy based on likely pathogens and site of infection.
Adjustment of antibiotics based on culture and sensitivity results.
Removal of infected devices: catheters, central lines, etc.
Supportive care: fluids, electrolytes, and organ support as needed.
Infection control measures: isolation, hand hygiene, environmental cleaning.
Surgical intervention for abscesses, debridement of infected tissue.
Patient and staff education on infection prevention strategies.
Implementation of antibiotic stewardship programs.
Regular review of infection control policies and procedures.
Monitoring for and managing complications of HAIs.
Multidisciplinary approach involving infectious disease specialists, microbiologists, and infection control teams.

Complications

Prognosis

Varies depending on the type and severity of infection.
Prompt diagnosis and appropriate treatment improve outcomes.
Mortality higher in ICU patients and those with comorbid conditions.
Prognosis poorer with multidrug-resistant infections.
Regular monitoring and infection control measures critical for prevention.
Follow-up care important to prevent recurrence and manage complications.
Healthcare facility’s adherence to infection control protocols impacts overall prognosis.
Good prognosis with effective infection control and management strategies.

Key points

Infection