Pharyngeal colonization by gram-negative bacilli in aspiration-prone persons

Area of Science:

• Microbiology
• Infectious Diseases
• Clinical Medicine

Background:

• Gram-negative bacillary pneumonia is a serious infection.
• Certain patient groups, like alcoholics and diabetics, are more prone to this type of pneumonia.
• The role of pharyngeal colonization by Gram-negative bacilli in this predisposition is not fully understood.

Purpose of the Study:

• To compare the prevalence of Gram-negative bacilli in the pharyngeal flora of patients at risk for Gram-negative pneumonia versus control groups.
• To investigate if increased colonization by Gram-negative bacilli is a factor in the susceptibility of alcoholics and diabetics to pneumonia.

Main Methods:

• Quantitative cultures of saline gargles were used to assess pharyngeal flora.
• Prevalence of Gram-negative bacilli was compared between chronic alcoholics, diabetics, epileptics, narcotic addicts, and normal control subjects.

Main Results:

• Pharyngeal Gram-negative bacilli were significantly more prevalent in alcoholics (35%) and diabetics (36%) compared to controls (18%).
• Higher counts (≥100 bacilli/mL) were also significantly more common in alcoholics (14%) and diabetics (24%) than controls (5%).
• Enterobacter sp, Klebsiella pneumoniae, and Escherichia coli were the most frequently isolated Gram-negative bacilli.

Conclusions:

• Alcoholics and diabetics exhibit increased colonization of their pharyngeal flora by Gram-negative bacilli.
• This heightened colonization may be a contributing factor to the increased risk of Gram-negative pneumonia observed in these patient populations.