Saturday, 1 December 2018

Gram-negative bacteria increase mortality


Alterations to the respiratory microbiome have been identified as a predisposing factor of interstitial lung diseases (ILD). In a new study, researchers studied the influence of bacterial virulence on clinical outcomes patients hospitalized with ILD patients. The authors found that the use of immunosuppressive medications or antifibrotics had no influence on the outcomes including development of resistant pathogens in patients.

Researchers conducted a retrospective analysis of 472 patients with ILD who were admitted to a large tertiary care academic center from Jan. 1st, 2010, to Dec. 31st, 2016. Patient data were extracted from electronic records using ICD-9 and ICD-10 billing codes for various ILD. The majority of the patients had either pulmonary fibrosis or sarcoidosis.

One hundred and seventy respiratory cultures were collected in this population. The majority of the respiratory isolates were gram-negative pathogens (39 percent Pseudomonas and 18 percent other gram-negative organisms); 27 percent were methicillin-resistant staphylococcus aureus (MRSA). Patients infected with gram-negative organisms (other than Pseudomonas) and MRSA had the highest 30-day mortality (39 percent and 32 percent respectively) compared with lower mortality for those infected with Pseudomonas and other gram positive organisms (7 percent and 14 percent respectively). Patients infected with gram-negative organisms other than Pseudomonas also had higher rates of vasopressin administration compared with those infected with other organisms. Rates of ICU admission also differed according to organism that was cultured. These associations persisted even after adjustment for the other variables including type of ILD, age, gender, comorbid conditions and smoking history. There was no association between the use of immunosuppressant medications or antifibrotics and the development of resistant pathogens.

See:

Hira Iftikhar, Chengda Zhang, Girish Balachandran Nair. Role of Respiratory Pathogens in Disease Outcomes in Hospitalized Patients With Interstitial Lung Disease. Chest, 2018; 154 (4): 445A DOI: 10.1016/j.chest.2018.08.405

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

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