Outbreak-associated Salmonella Baildon found in wastewater demonstrates how sewage monitoring can supplement traditional disease surveillance

Nkuchia M. M'ikanatha, Zoe S. Goldblum, Nicholas Cesari, Erin M. Nawrocki, Yezhi Fu, Jasna Kovac, Edward G. Dudley

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Non-typhoidal Salmonella is a common cause of gastroenteritis worldwide, but current non-typhoidal Salmonella surveillance is suboptimal. Here, we evaluated the utility of wastewater monitoring to enhance traditional surveillance for this foodborne pathogen. In June 2022, we tested raw sewage collected twice a week from two treatment plants in central Pennsylvania for non-typhoidal Salmonella and characterized isolates using whole-genome sequencing. We recovered 43 Salmonella isolates from wastewater samples, differentiatedby genomic analysis into seven serovars: 16 Panama (37.2%), 9 Senftenberg (20.9%), 8 Baildon (18.6%), and 3 or fewer of four other serovars. We assessed genetic relatedness and epidemiologic links between these wastewater isolates with those from patients with salmonellosis. All S. Baildon isolates from wastewater were genetically similar to those associated with a known contemporaneous salmonellosis outbreak. S. Baildon from wastewater and 42 outbreak-related isolates in the national outbreak detection database had the same core genome multilocus sequence typing, and outbreak code differedby zero or one single polynucleotide polymorphism. One of the 42 outbreak-related isolates was obtained from a patient residing in the wastewater sample collection catchment area, which serves approximately 17000 people. S. Baildon is a rare serovar (reported in <1% cases nationally, over fiveyears). Our study underscores the value of monitoring sewage from a definedpopulation to supplement traditional surveillance methods for the evidence of Salmonella infections and to determine the extent of outbreaks. IMPORTANCE During the COVID-19 pandemic, monitoring for SARS-CoV-2 in wastewater was highly effectivein identifying the variants of concern earlier than clinical surveillance methods. Here, we show that monitoring domestic sewage can also augment traditional reporting of foodborne illnesses to public health authorities. Our study detected multiple Salmonella enterica serovars in samples from two wastewater treatment plants in central Pennsylvania. Using whole-genome sequencing, we demonstrated that the isolates of variant S. Baildon clustered with those from a foodborne salmonellosis outbreak that occurred in a similar time frame. Cases were primarily from Pennsylvania, and one individual lived within the wastewater treatment catchment area. This study highlights the effectivenessof domestic sewage testing as a proactive public health strategy to track and respond to infectious disease outbreaks.

Original languageEnglish (US)
Article numbere0082524
JournalJournal of clinical microbiology
Volume62
Issue number10
DOIs
StatePublished - Oct 2024

All Science Journal Classification (ASJC) codes

  • Microbiology (medical)

Fingerprint

Dive into the research topics of 'Outbreak-associated Salmonella Baildon found in wastewater demonstrates how sewage monitoring can supplement traditional disease surveillance'. Together they form a unique fingerprint.

Cite this