Pseudomonas aeruginosa is the Most Common Causative Agent in Nosocomial Sinusitis in the ICU

The most common causative agent in nosocomial sinusitis in the ICU is Pseudomonas aeruginosa. 1, 2

Microbiology of Nosocomial Sinusitis in ICU

Nosocomial sinusitis in ICU patients is typically polymicrobial and predominantly caused by gram-negative bacilli, with Pseudomonas aeruginosa being the most frequently isolated pathogen 1
In a microbiological study specifically examining ICU patients with confirmed maxillary sinusitis, Pseudomonas aeruginosa was identified in 29% of sinus punctures, making it the most common pathogen 2
Other common gram-negative pathogens include Proteus mirabilis (26%) and Acinetobacter baumannii (14%), highlighting the predominance of gram-negative organisms in this setting 2
This pattern differs significantly from community-acquired sinusitis, where Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis predominate 3

The presence of devices such as nasotracheal tubes and nasogastric tubes is a major risk factor, as they obstruct normal sinus drainage and create an environment conducive to bacterial growth 1
Unlike community-acquired sinusitis, nosocomial sinusitis in ICU patients is characterized by gram-negative enterics (P. aeruginosa, Klebsiella pneumoniae, Enterobacter species) and less commonly gram-positive cocci (staphylococci and streptococci) 3
Prolonged hospitalization and exposure to antimicrobial therapy further increase the risk of developing nosocomial sinusitis with resistant organisms like Pseudomonas aeruginosa 4

Diagnosis requires a high index of suspicion as clinical features are often subtle, limited to unexplained fever and mucopurulent nasal discharge 1
CT scan of paranasal sinuses is the preferred imaging modality for diagnosis 1, 5
Maxillary sinus puncture with culture is the gold standard for microbiological diagnosis, as nasal swabs have limited diagnostic value with only 63% correlation with sinus puncture results 2

Treatment involves removal of all nasal tubes when possible, sinus drainage and lavage, and appropriate antimicrobial therapy based on culture results 1, 5
Given the high prevalence of Pseudomonas aeruginosa, empiric antibiotic therapy should include antipseudomonal coverage 4, 5
For severe infections with multidrug-resistant Pseudomonas aeruginosa, combination therapy consisting of an antipseudomonal beta-lactam with an aminoglycoside or fluoroquinolone is recommended 4
Treatment failures are common, and drainage with indwelling catheters is sometimes necessary 5

Nosocomial sinusitis can lead to serious complications including pneumonia, sepsis, meningitis, and intracranial abscesses if not promptly diagnosed and treated 2, 6
Patients with nosocomial sinusitis are more likely to develop pneumonia than those without sinusitis, as the sinus can provide a bacterial reservoir from which organisms may seed the tracheobronchial tree 7
The association between sinusitis and pneumonia is mainly due to Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii 7

Preventive measures include preferential use of orotracheal rather than nasotracheal intubation 7
Regular mobilization of patients when possible 6
Consideration of early tracheostomy in patients requiring prolonged mechanical ventilation 5