Genomic analysis of Chlamydia psittaci from a multistate zoonotic outbreak in two chicken processing plants

Area of Science:

• Zoonotic bacterial infections
• Genomic epidemiology
• Food safety

Background:

• Chlamydia psittaci is an avian pathogen that can cause psittacosis in humans.
• Poultry processing plant workers are at risk of occupational exposure to Chlamydia psittaci.
• Multistate outbreaks of Chlamydia psittaci have significant public health and economic implications.

Purpose of the Study:

• To characterize Chlamydia psittaci isolates from a human outbreak linked to poultry processing plants.
• To determine the genetic relatedness of the isolates and identify the source of infection.
• To inform public health interventions and prevent future outbreaks.

Main Methods:

• Clinical specimens from ill workers were collected.
• Bacterial isolates were identified as Chlamydia psittaci.
• Whole genome sequencing was performed on the isolates.
• Phylogenetic analysis was used to determine genetic similarity.

Main Results:

• Four Chlamydia psittaci isolates were recovered from workers in two processing plants.
• All isolates were highly similar to Chlamydia psittaci genotype D.
• The isolates differed by only two single nucleotide polymorphisms, indicating a common source.

Conclusions:

• The multistate outbreak was caused by a common source of Chlamydia psittaci genotype D.
• Poultry processing environments can be a source of human Chlamydia psittaci infections.
• Genomic sequencing is a valuable tool for investigating bacterial outbreaks and identifying sources.