Multistate outbreaks of Salmonella infections linked to imported Maradol papayas – United States, December 2016–September 2017

Abstract

Foodborne salmonellosis causes approximately 1 million illnesses annually in the United States. In the summer of 2017, we investigated four multistate outbreaks of Salmonella infections associated with Maradol papayas imported from four Mexican farms. PulseNet initially identified a cluster of Salmonella Kiambu infections in June 2017, and early interviews identified papayas as an exposure of interest. Investigators from Maryland, Virginia and Food and Drug Administration (FDA) collected papayas for testing. Several strains of Salmonella were isolated from papayas sourced from Mexican Farm A, including Salmonella Agona, Gaminara, Kiambu, Thompson and Senftenberg. Traceback from two points of service associated with illness sub-clusters in two states identified Farm A as a common source of papayas, and three voluntary recalls of Farm A papayas were issued. FDA sampling isolated four additional Salmonella strains from papayas sourced from Mexican Farms B, C and D. In total, four outbreaks were identified, resulting in 244 cases with illness onset dates from 20 December 2016 to 20 September 2017. The sampling of papayas and the collaborative work of investigative partners were instrumental in identifying the source of these outbreaks and preventing additional illnesses. Evaluating epidemiological, laboratory and traceback evidence together during investigations is critical to solving and stopping outbreaks.

Genomic diversity of Salmonella enterica isolated from papaya samples collected during multiple outbreaks in 2017

“…Whole-genome sequence analyses of 55 S. enterica isolated from 12 papaya samples that were collected during outbreaks confirmed the conclusions reached by epidemiologic and traceback investigations that contaminated papayas were responsible [2]. Ten groups of isolates were identified with SNP analyses that are consistent with predicted serovar assignments.…”

“…Whole-genome sequence (WGS) data collected by the GenomeTrakr Network [1] and analysed by the FDA unambiguously supported the epidemiologic and traceback evidence that implicated papayas contaminated with S. enterica [2]. These investigations resulted in multiple recalls of contaminated products (fda.gov/food/outbreaks-foodborne-illness/fda-investigates-multiple-salmonella-outbreak-strains-linked-papayas) and heightened monitoring.…”

“…The epidemiologic and traceback investigations into the outbreaks, including the role of WGS analysis, are described in Hassan et al [2] To gain a greater understanding of the genetic diversity of S. enterica that were collected from the papayas, we present here a retrospective genomic analysis of the 55 isolates.…”

Efficacy assessment of various natural and organic antimicrobials against Escherichia coli O157:H7, Salmonella enteritidis and Listeria monocytogenes

“…In July 2016, an outbreak of Shiga toxin-producing Escherichia coli O157 PT34 was notified to WHO in England and Wales. In 2016, WHO has been reported four multistate outbreaks of human Salmonella infections by the National International Health Regulations Focal Point of the USA (Hassan et al 2019). It was a case reported that some tourists in Egypt and Turkey had endured from foodborne illnesses of unknown origin (Todd 2016).…”

Complete genome and plasmid sequences of a multidrug-resistant Salmonella enterica subsp. enterica serovar Panama isolate from a German cattle farm

“…The serovar Panama is rarely discussed but has a strong association with invasive diseases and is linked with infections in humans [2]. S. Panama is known to cause a significant proportion of Salmonella infections in the pig industry [3]. This serovar has also been isolated from reptiles and environmental reservoirs, rarely from cattle but is in general considered as understudied [2,4].…”