Revisiting the Biological Behavior of Salmonella enterica in Hydric Resources: A Meta-Analysis Study Addressing the Critical Role of Environmental Water on Food Safety and Public Health

Abstract

The increasing number of studies reporting the presence of Salmonella in environmental water sources suggests that it is beyond incidental findings originated from sparse fecal contamination events. However, there is no consensus on the occurrence of Salmonella as its relative serovar representation across non-recycled water sources. We conducted a meta-analysis of proportions by fitting a random-effects model using the restricted maximum-likelihood estimator to obtain the weighted average proportion and between-study variance associated with the occurrence of Salmonella in water sources. Moreover, meta-regression and non-parametric supervised machine learning method were performed to predict the effect of moderators on the frequency of Salmonella in non-recycled water sources. Three sequential steps (identification of information sources, screening and eligibility) were performed to obtain a preliminary selection from identified abstracts and article titles. Questions related to the frequency of Salmonella in aquatic environments, as well as putative differences in the relative frequencies of the reported Salmonella serovars and the role of potential variable moderators (sample source, country, and sample volume) were formulated according to the population, intervention, comparison, and outcome method (PICO). The results were reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyzes statement (PRISMA). A total of 26 eligible papers reporting 148 different Salmonella serovars were retrieved. According to our model, the Salmonella frequency in non-recycled water sources was 0.19 [CI: 0.14; 0.25]. The source of water was identified as the most import variable affecting the frequency of Salmonella, estimated as 0.31 and 0.17% for surface and groundwater, respectively. There was a higher frequency of Salmonella in countries with lower human development index (HDI). Small volume samples of surface water resulted in lower detectable Salmonella frequencies both in high and low HDI regions. Relative frequencies of the 148 serovars were significantly affected only by HDI and volume. Considering that serovars representation can also be affected by water sample volume, efforts toward the standardization of water samplings for monitoring purposes should be considered. Further approaches such as metagenomics could provide more comprehensive insights about the microbial ecology of fresh water and its importance for the quality and safety of agricultural products.

Prevalence and whole‐genome sequencing characterization of Salmonella in urban karst groundwater and predominantly groundwater‐fed surface waters for serotypes and antimicrobial resistance

“…For example, monitoring activities can target the three sampling sites (Bypass Cave well, Durbin well, and the Barren River) that contributed over half of Salmonella ‐positive samples in the month of November and summer and fall seasons. The higher prevalence of Salmonella in the mainly groundwater‐fed surface water in the Bowling Green, KY, study is consistent with previous studies reporting Salmonella from surface waters with differing land use (Cho et al., 2022; Hubbard et al., 2020; Rocha et al., 2022). Salmonella was reported from all nine surface water samples, and 77% ( n = 13) of groundwater samples collected near poultry farms (Hubbard et al., 2020).…”

“…Consistent with findings herein, Rubislaw, Newport, and Hartford were among the top five serotypes identified from surface waters (rivers and streams) in Georgia (Cho et al., 2022). Similarly, Newport was the most common serotype across published studies focusing on ground‐ and surface waters (Rocha et al., 2022); it was also the most frequently isolated from water streams examined in the vegetable‐producing region in Virginia (Bell et al., 2015) and Maryland Eastern shore (Callahan et al., 2019) of the United States. Taken together, these three serotypes are frequently present both in the ground and surface waters and commonly associated with human infections (Cho et al., 2022).…”

Prevalence of STEC virulence markers and Salmonella as a function of abiotic factors in agricultural water in the southeastern United States

“…Additional factors such as land use, the presence of wild animals, and concentrated animal feeding operations (CAFO) are relevant factors for microbial contamination ( Strawn et al, 2013b ). As surface water is exposed to the environment and animals are more susceptible to microbial contamination, wild animal activity (e.g., birds, reptiles, wild hogs) was observed in all the ponds’ surrounding areas, which may have contributed to the ponds’ microflora ( Rocha et al, 2022 ). Poultry operations are often with a source of Salmonella and Campylobacter jejuni ( Vereen et al, 2013 ; Bardsley et al, 2021 ).…”

Water for Human Consumption in Rural Areas Worldwide: A Systematic Review of the Presence of <i>Cryptosporidium</i> spp. and <i>Giardia</i> spp.

“…To carry out the analysis, the variables were divided into the categories contained in Table 2. The HDI was classified in countries as low (< 0.8) and high (≥ 0.8), in accordance to what was applied by Rocha et al (2022).…”