Diversity of Campylobacter isolates from three activated sludge systems

Area of Science:

• Environmental microbiology
• Public health microbiology

Background:

• Thermophilic Campylobacter species are significant human and animal pathogens.
• Sewage systems can act as reservoirs for various pathogenic microorganisms.
• Understanding pathogen presence in wastewater is crucial for public health risk assessment.

Purpose of the Study:

• To identify and quantify thermophilic Campylobacter strains in sewage treatment plants in Rio de Janeiro, Brazil.
• To assess the potential role of different sewage treatment stages in Campylobacter survival.
• To determine the prevalence of specific Campylobacter species and biotypes in the studied environment.

Main Methods:

• Analysis of 390 sewage samples from three treatment plants.
• Isolation and identification of thermophilic Campylobacter strains.
• Biotype characterization of isolated Campylobacter species.

Main Results:

• 169 thermophilic Campylobacter strains were isolated from sewage samples.
• Pathogenic biotypes of Campylobacter were detected in activated sludge.
• Campylobacter jejuni was the most prevalent species (40.8%), followed by C. coli.
• C. jejuni biotype I (21.3%), C. coli biotype I (16%), and C. jejuni biotype II (14.8%) were the most common biotypes.
• Aeration tanks appeared to act as a barrier to Campylobacter survival.

Conclusions:

• Sewage treatment plants in Rio de Janeiro harbor thermophilic Campylobacter, including pathogenic strains.
• Wastewater treatment processes, particularly aeration, may reduce the load of viable Campylobacter.
• Continued surveillance is necessary to manage public health risks associated with Campylobacter in wastewater.