Transmission of Salmonella enterica by Macrosteles quadrilineatus. Summary of posterior estimates of all 10 subsets of sequences of Salmonella enterica subspecies enterica4,[5],12:i:- sequence type (ST) 34 collected from multiple sources in... We used publicly available whole-genome sequences of 1,431 Salmonella 4,[5],12:i:- ST34 isolates from the United States and Europe from 2008–2017, including sequences from 690 isolates from Europe (mainly from the United Kingdom and Denmark) and 741 isolates from multiple US states (Appendix 1). Interestingly, at the 48-h IAP time point, proportions of S. enterica-positive honeydew samples from M. quadrilineatus insects were significantly higher than those of M. persicae insects, independent of the diet (leaf or liquid). Although the mechanisms of internalization, survival, and/or transmission of these enteric phytobacterial pathogens by their insect vectors have been widely studied, the actual multiplication of these bacteria inside their insect vector remains unconfirmed. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website. This work was supported by the Global Food Venture-MnDRIVE Initiative, the National Institute of Food and Agriculture (Animal Health Formula Fund project MIN-62-091) of the US Department of Agriculture, the Rapid Agricultural Response Fund, and the Swine Disease Eradication Center at the University of Minnesota. Dr. Elnekave is a veterinarian and epidemiologist who has been working as a postdoctoral fellow in the Veterinary Population Medicine Department, University of Minnesota, and is a faculty member in the Koret School of Veterinary Medicine at the Robert H. Smith Faculty of Agricultural, Food and Environmental Sciences at the Hebrew University of Jerusalem, Israel. In this case, although the proportion of exclusively honeydew-positive samples was maintained, the proportion of double-positive samples (honeydew and liquid diet) was lower at the 48-h IAP time point than those observed at the 24-h IAP time point, 0.17 compared to 0.30, respectively. In a field survey, leafhoppers were some of the most abundant and consistently captured insects in both rangeland and leafy green production areas, in which Escherichia coli O157:H7-positive flies were also found (28). Similarly, infestation and feeding by some phytophagous insects enhanced the persistence of S. enterica on lettuce leaves (13). In a similar set of experiments, insects were fed for a 24-h AAP on S. enterica-inoculated liquid diet and two consecutive noninoculated liquid diets, and at the end of each inoculation access period (24- and 48-h IAP), the corresponding liquid diets were sampled and the percentage of noninoculated liquid diets positive for S. enterica was determined. Mather), Universidad Complutense, Madrid, Spain (J. Alvarez), Centers for Disease Control and Prevention. Similarly, the analysis of proportions for transmission and localization of S. enterica showed that internally contaminated insects transmitted S. enterica to both noninoculated leaf discs and liquid diets. Transmission of Multidrug-Resistant . Leaf discs and liquid diets were placed and confined, respectively, inside the cap of sterile microcentrifuge tubes and were used to feed individual Macrosteles quadrilineatus and Myzus persicae. Experiments were repeated 4 times, and the corresponding samples from M. persicae insects (n = 131) were examined. In fact, Talley et al. Relatively equal proportions of M. persicae insects that were internally contaminated were also externally contaminated, as signified by the lack of a dotted section of the vertical bar (Fig. Experiments were repeated 4 times, and honeydew samples from Myzus persicae (n = 90) and Macrosteles quadrilineatus (n = 169) insects were examined. Enter multiple addresses on separate lines or separate them with commas. Experiments were repeated 4 times, and Myzus persicae (n = 90) and Macrosteles quadrilineatus (n = 169) insects were examined. Yet associations between the collection location and the presence of blaCTX-M or qnrS1 genes were not significant (Table). After external wash, each insect was then homogenized in the remaining liquid with a MINIMITE cordless grinding tool (Dremel, Racine, WI), and both the wash and the homogenate were separately enriched and plated on LB-kan and XLD-kan, respectively. There are over 2,500 subtypes, including animal and human strains. Elnekave, E., Hong, S. L., Lim, S., Boxrud, D., Rovira, A., Mather, A. E....Alvarez, J. 2B). S. enterica was also recovered from the honeydew of both species. Insects were scored as S. enterica positive after external wash (A) or homogenization of the whole sample (B). 2A and B). You will be subject to the destination website's privacy policy when you follow the link. Additionally, excretion of S. enterica from adult insects was tested following similar procedures. The Ramón y Cajal postdoctoral contract from the Spanish Ministry of Economy, Industry and Competitiveness (MINECO) (RYC-2016-20422) was awarded to J.A. We applied the modeling approach to 10 subsets of 112 sequences selected from the study population. These strains were selected because they were responsible for salmonellosis outbreaks associated with contaminated fresh produce. After a 24-h acquisition access period, insects were moved onto two consecutive noninoculated leaf discs or liquid diets and allowed a 24-h inoculation access period on each of the two discs or sachets. Within each graph, bars sharing the same number of asterisks are not statistically different from each other (chi-square analysis, P < 0.01). To investigate the potential for phytophagous insects to ingest S. enterica acquired from contaminated plants, adult M. quadrilineatus and M. persicae insects were allowed to feed on leaf discs (4-mm diameter) excised from S. enterica-inoculated lettuce (∼104 CFU/mm2) for a 24-h acquisition access period (AAP). There are currently no vaccines clinically used to defend against Salmonella Paratyphi . CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. 1. Moreover, White et al. Yet introduction of resistant strains from the United States to Europe is also possible. Within each graph, bars sharing the same number of asterisks are not statistically different from each other (chi-square analysis, P < 0.01). The occurrence of several additional smaller introductions was suggested by 48 sequences (6 from Europe and 42 from the United States). Copyright © 2014, American Society for Microbiology. Additionally, McNemar's test was used to test for marginal homogeneity in contamination rates over time, based on proportions of insects testing positive for S. enterica. The level of specificity and complexity of these symbiotic relationships vary depending on the bacteria-insect combination and the frequency of cooccurrence of both organisms within the same plant or ecological niche (19). No significant differences were found among replications of the overall experiments; thus, means from all the replicates of each experiment were combined. Both internally and externally contaminated insects may increase the risk of dispersal of the pathogen within or among plants. Using a hemipteran insect pest-lettuce system, we investigated the potential for transmission and retention of S. enterica. In addition, the incidence of Salmonella 4,[5],12:i:- in humans increased only modestly (9.5%) during 2006–2011 but increased dramatically (78.3%) during 2011–2016 (8). 3B). This result suggests that transmission of the ingested S. enterica was far less than 100% efficient. If the infection spreads to the bloodstream, any organ can become infected (e.g., liver, gallbladder, bones, or meninges). In the United States, approximately 80 cases of paratyphoid fever caused by S. Paratyphi A are reported each year, 90% of which are acquired during international travel. However, the proportions of insects resulting in negative external contamination but positive for whole-insect homogenates were similar for both species (Fig. can attach, survive, and even replicate in or on confinement insects (42). The transmission rate decreased significantly when the acquisition source was changed to a liquid diet confined in Parafilm sachets, which presumably limited mechanical contamination of the insects. At the end of each 12-h period, the corresponding leaf discs were homogenized and subsequently enriched and plated on LB-kan and XLD-kan, respectively, and the percentage of S. enterica-contaminated leaf discs was determined. S. enterica populations tend to decline steadily over time on leaves of agricultural crops (2, 8, 9). Salmonella enterica spp. Salmonella can cause various diseases, such as food poisoning, gastrointestinal inflammation, typhoid fever, and sepsis.The CDC estimates that every year in the United States about 1.2 million people are infected with Salmonella, 23,000 need hospital … Salmonella enterica inoculum was verified by serial dilution before and after plant dip inoculation by being plated on Luria-Bertani (LB) (Difco/Becton, Dickinson, Franklin Lakes, NJ) medium amended with kanamycin to ensure that the bacterial concentration was constant throughout the inoculation process. However, the sources and routes of transmission of this Salmonella serotype are not well understood. However, even at the 48-h IAP time point, the transmission rate was approximately 20% when insects acquired from and transmitted the pathogen to liquid diets (Fig. A.E.M. Paratyphi are transmitted through drinking water and cause typhoid fever in humans. In this experiment, insects were moved through a series of leaf discs (inoculated and noninoculated); therefore, the AAP and each IAP were reduced to 12 h, considering that there was no need of an adjustment period to feed on liquid diets through Parafilm sachets. Within each graph, bars sharing the same number of asterisks are not statistically different from each other (chi-square analysis, P < 0.01). This increase probably resulted to a large extent from ST34 strains, in which this phenotype is predominant. Nontyphoidal Salmonella is the leading bacterial cause of food-borne illness in the United States, with an incidence of infection that has not significantly declined in more than a decade (2). 1 and 7 and Nicholas Keuler of the College of Agriculture and Life Sciences' Statistical Consulting Laboratory, UW-Madison, for his assistance with statistical analysis. In other cases of specific interactions, bacteria are internalized and disseminated by insects that serve as both vectors and overwintering hosts. Figure 2. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website. Although Salmonella is most often spread when a person eats contaminated food, the bacteria also can be passed between people and animals. These experiments were repeated 4 times, and 131 M. persicae and 202 M. quadrilineatus insects were examined. Proportions of S. enterica-contaminated leaves, liquid diets, insects, and honeydew were calculated, and significant differences among treatment main effects (diets and/or insect species) for individual experiments were tested with Pearson's chi-square test. Given time and overall unidirectionality of Salmonella 4,[5],12:i:- ST34 transmission from Europe to the United States, it is likely that the acquisition of AARGs to quinolones occurred independently in the United States and in Europe. To determine its origin in the United States, we reconstructed a time-scaled phylogeny with a discrete trait geospatial model. Persistence and growth of human bacterial pathogens on crop plants increase the chance that an infectious dose would survive until harvest, posing a public health threat (14, 15). A number of its serovars are serious human pathogens Epidemiology. Plant inoculation.Lettuce (Lactuca sativa cv. Several pest insects of human and livestock habitations are known as vectors of Salmonella enterica; however, the role of plant-feeding insects as vectors of S. enterica to agricultural crops remains unexamined. Synanthropic and coprophagic insects are recognized as vectors of human enteric pathogens, and many have been implicated in not just the dispersal but also in the survival and multiplication of S. enterica (42). Excretion of ingested S. enterica onto leaves could further represent an important mechanism of transmission. Proportion of S. enterica-positive samples resulting from insects that were fed inoculated leaf discs for a 24-h acquisition access period. The incidence of S. Wangata is increasing and transmission is suspected to be via a non-food source. However, further investigation of the travel history associated with these cases may be required because the acquisition of mcr genes may be travel associated (15). These sequences represented 33% (474/1,431) of the study population and included 242 sequences from Europe (76% from humans, 8% from food products, 8% from livestock, and 8% from other sources) and 232 from the United States (62% from humans, 13% from food products, 21% from livestock, and 3% from other sources). (10) recently reported that according to the National Antibiotic Resistance Monitoring System, the percentage of ASSuT-resistant Salmonella 4,[5],12:i:- from humans increased from 17% in 2009 to 59.1% in 2015 (out of all Salmonella 4,[5],12:i:- clinical isolates from humans). Within each graph, the proportions of S. enterica-positive samples between treatments were significantly different from each other (chi-square analysis, P < 0.01). Salmonella enterica serovar Wangata is an important pathogen in New South Wales (NSW), Australia. Selected plants were dip inoculated with either sterile water, as a control, or with an S. enterica cocktail (∼108 CFU/ml) as previously described (13). However, precise knowledge of the time of introduction and the initial influx of clinical cases caused by this serotype in the United States is not available because of inconsistent reporting before 2004 (3). More than 2600 serotypes of S. enterica have been identified (Issenhuth-Jeanjean et al., 2014), with Enteritidis being one of the most common serotypes that are responsible for Salmonella infections in humans. Transmission of Multidrug- Resistant Salmonella enterica Subspecies enterica 4,[5],12:i:- Sequence Type 34 between Europe and the United States Ehud Elnekave, Samuel L. Hong, Seunghyun Lim, Dave Boxrud, Albert Rovira, Alison E. Mather, Andres Perez, Julio Alvarez 2020;26(12):3034-3038. https://dx.doi.org/10.3201/eid2612.200336. Localization of Salmonella enterica in or within phytophagous hemipterans. Subspecies . Yet AARGs conferring resistance to quinolones were not found in Salmonella 4,[5],12:i:- ST34 strains from Europe collected before 2010 (1), and therefore our findings may reflect an increasing prevalence of these resistance determinants. Experiments were repeated 3 times, and Myzus persicae (n = 72) and Macrosteles quadrilineatus (n = 71) insects were examined. The clone in the United States was introduced from Europe on multiple occasions in the early 2000s. Therefore, based on the working definitions of vectors, and our results, we propose that phytophagous insects should be considered potential vectors of S. enterica in and among plants. Moreover, there were no significant differences between proportions of positive, noninoculated leaf discs or liquid diets and the externally washed S. enterica-positive samples (Table 1). To humans include 1 German and Susan Paskewitz for providing constructive criticism on earlier versions of the bacterium of! 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