Signs and Symptoms of Acinetobacter baumannii Infection
Acinetobacter baumannii infections primarily manifest as healthcare-associated infections with clinical presentations varying by site of infection, most commonly affecting critically ill patients in intensive care units. 1, 2
Common Clinical Manifestations
Pneumonia/Ventilator-Associated Pneumonia
- Most common manifestation in intensive care settings, particularly in mechanically ventilated patients 3
- Presents with respiratory deterioration, purulent secretions, and radiographic infiltrates 1
- Often occurs in patients with prolonged mechanical ventilation 4
Bloodstream Infections
- Range from transient bacteremia to severe septic shock 1
- Clinical manifestations are non-specific and similar to bacteremia caused by other pathogens 5
- Most common sources are intravascular catheters and respiratory tract 5
- Associated with high crude mortality rates (30-75%) 4
Central Nervous System Infections
- Post-neurosurgical meningitis/ventriculitis 1
- Presents with fever, altered mental status, meningeal signs, and CSF abnormalities 1
- May occur following neurosurgical procedures or trauma 1
Wound and Soft Tissue Infections
- Common in surgical sites and traumatic wounds 6
- Presents with local inflammation, purulent discharge, and delayed healing 2
- Often seen in burn patients and following traumatic injuries 3
Urinary Tract Infections
- Less common manifestation 6
- Usually associated with urinary catheterization or instrumentation 5
- Presents with typical UTI symptoms (dysuria, frequency, cloudy urine) 2
Risk Factors for A. baumannii Infection
- Prolonged ICU stay 4
- Mechanical ventilation 3
- Recent invasive procedures 5
- Prior broad-spectrum antimicrobial therapy 4
- Presence of indwelling devices (central venous catheters, urinary catheters) 5
- Immunocompromised state 2
Distinguishing Colonization from Infection
- A. baumannii can form biofilms and colonize surfaces without causing infection 1
- Isolation from clinical specimens may represent colonization rather than true infection 5
- Clinical evaluation is essential to differentiate colonization from infection to avoid unnecessary treatment 5
Common Sites for Surveillance Cultures
- Nose, throat, axilla, groin, rectum, open wounds, and endotracheal aspirates 1
- Single-site cultures (e.g., nasal) have low sensitivity (13-29%) 1
- Multi-site sampling increases detection sensitivity to approximately 50% 1
Special Considerations
- A. baumannii has a propensity to cause outbreaks and become endemic in healthcare settings 1
- Multidrug-resistant (MDR), extensively drug-resistant (XDR), or pandrug-resistant (PDR) strains are increasingly common, complicating treatment 6
- Environmental persistence contributes to nosocomial spread and outbreaks 1
- Community-acquired infections are rare but may occur in patients with comorbidities such as diabetes, chronic lung disease, or immunosuppression 2