Megaesophagus microbiota: a qualitative and quantitative analysis.

Bacterial overgrowth in the esophageal lumen in patients with megaesophagus can be the cause of recurring pulmonary infections, infectious complications due to surgical or endoscopic procedures, and the development of dysplasia of the esophageal mucosa and cancer. Despite this, esophageal microbiota in the megaesophagus have never been studied. The aim of this study was to analyze qualitatively and quantitatively the microbiota in chagasic megaesophagus in comparison to the normal esophagus. Twenty-five patients (10 men and 15 women), ranging in age from 24 to 74 years (mean years), were prospectively studied from March to September 2000. Fifteen patients with chagasic megaesophagus were divided into three subgroups (n = 5 patients in each) according to the grade of esophageal dilation: MG1 = megaesophagus grade I; MG2 = megaesophagus grade II; and MG3 = megaesophagus grade III. Another group of 10 patients without esophageal disease served as a control group. Samples were collected using a method especially developed to avoid contamination with microorganisms of the oral cavity and oropharynx. In the control group, 40% of the cultures were positive with the genus Streptococcus predominating and concentrations varying from 10(1) to 10(2) colony-forming units/ml. In the megaesophagus group, 93.3% of the cultures were positive, with great variability in the bacteria and a predominance of various aerobic gram-positive bacteria (Streptococcus was most common) and anaerobic bacteria (Veillonella was most frequent) in concentrations that ranged from 10(1) to 10(5) colony-forming units/ml. The bacterial concentrations were generally more elevated in MG3 patients in comparison to MG1 and MG2 patients and the control group (P < 0.05). It was concluded that patients with megaesophagus have a variety of microbiota consisting mostly of aerobic gram-positive and anaerobic bacteria, in concentrations that varied according to the degree of esophageal dilation.