Prevalence of Escherichia coli in a Swine Nursery Facility Pre- and Post-Disinfection

During the spring of 2021, the Kansas State University Swine Early Wean Facility (SEW) experienced a notable increase in piglet morbidity and mortality. Piglet diarrhea was observed approximately 2 to 3 weeks post-weaning along with an increase in number of sudden mortalities. Necropsy samples were collected and confirmed for clinical diagnosis of Escherichia coli K88 infection by the Kansas State University Veterinary Diagnostic Laboratory. E. coli K88 can negatively impact performance of pigs and typically manifests as diarrhea, which can continue until death because of severe dehydration and metabolic acidosis or from terminal septicemia. Once present, E. coli, including E. coli K88, tends to persist in the environment unless vigorous efforts are successful at sanitation and disinfection. Therefore, the overall objective of this study was to determine the critical areas in need of improved disinfection at the nursery facility and to make recommendations based on environmental sampling results. The research team surveyed the most probable areas of contamination before sampling and identified six locations from which to collect environmental samples in each pen. These six locations, in addition to other common-use areas in the barn, were sampled using sponges and swabs from 10 pens at random both pre- and post-disinfection. After the completion of sampling, samples were enumerated using Sorbitol MacConkey Agar with cefixime and tellurite (CT-SMAC). E. coli was not detected from the common-use areas such as the water lines, office water faucets, and feed buckets. The dirtiest pen sample areas pre-disinfection included under rubber mats, inside and outside of waterers, and the floor slats. Disinfection significantly reduced (P \u3c 0.05) contamination of the floor slats and the waterer (inside and outside). While the slats were initially among the dirtiest samples, after cleaning, a 6.5 log reduction was observed. Conversely, contamination on the feeder surface and lip of the feeder was not significantly reduced post-disinfection (P \u3e 0.05). E. coli was recovered from every sample type post-sanitation. While the current cleaning process was successful in reducing bacterial contamination, these data suggest it could be further improved by using a more effective and thorough cleaning process, as some residual contamination remained. Recommendations might include the use of a stronger disinfectant with power washing, higher water pressure, and increased water temperatures, among others. Perhaps physical scrubbing in hard-to-reach locations, such as rubber mats and water cups might also be helpful

Determining the Impact of Probicon L28 and BioPlus 2B on Finishing Pig Growth Performance and Carcass Characteristics

These data represent the growth performance of pigs enrolled in a study to determine the impact of two direct fed microbial products on Salmonella and Escherichia coli prevalence pre- and post-harvest. A total of 650 finishing pigs in two groups were randomly assigned to pen via a completely randomized design, and pens were assigned to one of three treatments: 1) a control treatment with pigs fed a standard corn-soybean meal finishing diet (with no added probiotic); 2) the control diets with Probicon L28 (NexGen Innovations, LLC, Lubbock, TX) supplemented through water lines using a water medicator system at a target concentration of 1.0 × 106 CFU/head/day; and 3) the control diet with added BioPlus 2B (5.0 × 108 CFU/lb of feed; ~3.0 × 109 CFU/ head/day; CHR Hansen, Inc, Milwaukee, WI). No evidence of difference (P \u3e 0.10) between treatments was observed for overall ADG, ADFI, or F/G or any of the carcass traits. However, there was a tendency for a treatment effect for loin depth (P = 0.070). Pigs fed the BioPlus 2B treatment had numerically greater loin depth compared to other treatments, but there were no significant pairwise differences between treatments (P \u3e 0.05). The results of this study suggested that probiotics used in this study and supplied through the water or feed had no impact on growth or carcass characteristics of finishing pigs

Exploring the Use of Probicon L28 and BIOPLUS 2B as Direct-Fed Microbials to Reduce Salmonella and Shiga Toxin-Producing Escherichia coli in Market Pigs

Pigs are hosts for Salmonella and Shiga toxin-producing Escherichia coli (STEC) and these pathogens can commonly be isolated from the pig farm environment. Pigs can carry pathogens to the abattoir and contaminate pork products, posing a risk to public health. Identifying an intervention that effectively reduces pathogens in commercial pigs before harvest is imperative. Due to the need for effective pre-harvest interventions in the pig industry, the objective of this study was to investigate BIOPLUS 2B (Bacillus licheniformis and Bacillus subtilis) and Probicon L28 (Lactobacillus salivarius L28) as pre-harvest interventions to reduce Salmonella and STEC in commercial growing-finishing pigs. Two groups of pigs (group 1, N = 294; group 2, N = 356, initial body weight = 106.6 lb) were fed a standard corn-soybean meal (SBM) finishing diet according to the following treatments: Probicon L28 supplementation through water lines at 1.0 × 106 CFU/head/day (Probicon); BIOPLUS 2B supplemented at 3.0 × 109 CFU/head/day (BIOPLUS 2B); and a control with no added probiotic (Control). With each group of pigs, 12 pens were used per treatment (N = 24 total), for a total of 36 pens per group (N = 72 pens total). Each group was sampled upon arrival/baseline, midway through the grow-finish phase/6 weeks post-placement, and prior to loadout/13 weeks post-placement to collect fecal samples (4 pigs/pen), boot covers (2/pen), and ropes (1/pen). Market pigs were followed to the abattoir and superficial inguinal lymph nodes (SILNs) were collected. All samples were analyzed for STEC (stx, eae genes, and O157:H7, and O26, O111, O121 O45, O103, and O145 serogroups) and Salmonella using the BAX System (real-time polymerase chain reaction). Overall, Salmonella and O111 prevalence was very low for all sample types, and Escherichia coli O157:H7 was not detected in any samples throughout the study. When compared to the control, there was no evidence (P \u3e 0.05) that BIOPLUS 2B and Probicon L28 impacted the prevalence of STEC (stx and eae genes) or serogroups O26, O121, O45, O103, and O145 in feces, boot covers, ropes, and SILNs of market pigs

Evaluation of Peroxyacetic Acid and Chlorine as Treatments for Surface Water for Post-Harvest Uses in the Produce Industry

Nearly half of foodborne illnesses are linked to produce and nuts, and water used for produce post-harvest activities can contribute to contamination. Surface water serves as an economical source for agricultural activities; however, exposure to the environment increases microbial risks and impacts its physicochemical characteristics. In this study, peroxyacetic acid (PAA) and chlorine (Cl) were evaluated as treatments for simulated surface water to determine their efficacy at achieving ‘no detectable generic Escherichia coli’ in 100 mL. Simulated surface water was prepared to turbidities of 2 and 100 NTU, adjusted to pH 6.5 or 8.4, equilibrated to 32 or 12 °C, inoculated with 5 logs per mL of non-pathogenic (generic) E. coli, and treated with Cl 25 ± 2 ppm, PAA 75 ± 5 ppm, or sterile water control (W). Dey-Engley neutralization was followed by enumeration on E. coli/Coliform Petrifilm at times (t) 0 to 2880 min (48 h) post-treatment. When not detected, treatments were further evaluated through enrichment in 2X Brain Heart Infusion (BHI) broth. Enrichments were streaked on MacConkey agar (MAC) to confirm E. coli absence. All Cl and PAA treated samples were below the test limit of detection (<5 CFU/mL), and E. coli was not detected in 5 mL enrichments even at t = 0 (shortly after treatment). These data suggest that Cl and PAA interventions may be effective for treating surface water for post-harvest uses

Rapid Detection of Salmonella in Bovine Lymph Nodes Using a Commercial Real-Time PCR System

Abstract Rapid Salmonella detection is needed to help prevent the distribution of contaminated food products. Using traditional culture methods, Salmonella detection can take up to 3-5 days. Using an improved protocol and a commercial real-time PCR system, we have shortened the detection time to less than 24 hr with comparable sensitivity and specificity to traditional Salmonella culture methods

Substantial within-Animal Diversity of \u3ci\u3eSalmonella\u3c/i\u3e Isolates from Lymph Nodes, Feces, and Hides of Cattle at Slaughter

Lymph nodes (mandibular, mesenteric, mediastinal, and subiliac; n=68) and fecal (n=68) and hide (n=35) samples were collected from beef carcasses harvested in an abattoir in Mexico. Samples were analyzed for Salmonella, and presumptive colonies were subjected to latex agglutination. Of the isolates recovered, a subset of 91 was characterized by serotyping, pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility phenotyping. Salmonella was isolated from 100% (hide), 94.1% (feces), 91.2% (mesenteric), 76.5% (subiliac), 55.9% (mandibular), and 7.4% (mediastinal) of samples. From the 87 typeable isolates, eight Salmonella enterica serotypes, including Kentucky (32.2%), Anatum (29.9%), Reading (17.2%), Meleagridis (12.6%), Cerro (4.6%), Muenster (1.1%), Give (1.1%), and Mbandaka (1.1%), were identified. S. Meleagridis was more likely (P=0.03) to be recovered from lymph nodes than from feces or hides, whereas S. Kentucky was more likely (P=0.02) to be recovered from feces and hides than from lymph nodes. The majority (59.3%) of the Salmonella isolates were pansusceptible; however, multidrug resistance was observed in 13.2% of isolates. Typing by PFGE revealed that Salmonella strains generally clustered by serotype, but some serotypes (Anatum, Kentucky, Meleagridis, and Reading) were comprised of multiple PFGE subtypes. Indistinguishable PFGE subtypes and, therefore, serotypes were isolated from multiple sample types, and multiple PFGE subtypes were commonly observed within an animal. Given the overrepresentation of some serotypes within lymph nodes, we hypothesize that certain Salmonella strains may be better at entering the bovine host than other Salmonella strains or that some may be better adapted for survival within lymph nodes. Our data provide insight into the ecology of Salmonella within cohorts of cattle and offer direction for intervention opportunities

Impact of the Probiotic Organism Megasphaera elsdenii on Escherichia coli O157:H7 Prevalence in Finishing Cattle

Feedlot cattle commonly shed the foodborne pathogen Escherichia coli O157:H7 in their feces. Megasphaera elsdenii (ME), a lactic acid-utilizing bacterium, is commonly administered to cattle to avoid lactate accumulation in the rumen and to control ruminal acidosis. The impact of administering ME on foodborne pathogen prevalence, specifically E. coli O157:H7, has not been explored. The purpose of this study was to quantify E. coli O157:H7 prevalence in finishing cattle administered ME. Cattle (n = 448) were assigned to treatments in a randomized complete block design with repeated measurements over two sampling periods. Treatments were arranged as a 2 × 2 factorial containing: ruminally protected lysine (RPL; included for a complementary study) fed at 0% or 0.45% of diet dry matter; with or without ME. Freeze-dried ME was administered as an oral drench (1 × 1010 CFU/steer on day one) and then top dressed onto basal diets (1 × 107 CFU/steer) daily thereafter. Rectoanal mucosal swabs (RAMS) were obtained from animals before harvest to determine the E. coli O157:H7 prevalence. The inclusion of RPL (P = 0.2136) and ME (P = 0.5012) did not impact E. coli O157:H7 prevalence, and RPL was not included in any significant interactions (P > 0.05). A significant interaction was observed between ME and sampling period (P = 0.0323), indicating that the effect of ME on E. coli O157:H7 prevalence varied over the sampling period. A diet containing ME reduced the odds of E. coli O157:H7 prevalence by 50% during sampling period 1 (8.0% and 14.7% for cattle with and without ME, respectively) and increased the odds by 23% during sampling period 2 (10.8% and 8.9% for cattle with and without ME, respectively). Administering ME in cattle diets did not impact E. coli O157:H7 in feedlot cattle. This is the first study to investigate the use of ME as a preharvest food safety intervention in cattle, and additional research is necessary to determine the efficac

Cross-sectional Study Examining \u3ci\u3eSalmonella enterica\u3c/i\u3e Carriage in Subiliac Lymph Nodes of Cull and Feedlot Cattle at Harvest

Bovine peripheral lymph nodes (LNs), including subiliac LNs, have been identified as a potential source of human exposure to Salmonella enterica, when adipose trim containing these nodes is incorporated into ground beef. In order to gain a better understanding of the burden of S. enterica in peripheral LNs of feedlot and cull cattle, a cross-sectional study was undertaken in which 3327 subiliac LNs were collected from cattle at harvest in seven plants, located in three geographically distinct regions of the United States. Samples were collected in three seasons: Fall 2010, Winter/Spring 2011, and Summer/Fall 2011. A convenience sample of 76 LNs per day, 2 days per season (approximately 1 month apart), was collected per plant, from carcasses held in the cooler for no less than 24 h. Every 10th carcass half on a rail was sampled, in an attempt to avoid oversampling any single cohort of cattle. Median point estimates of S. enterica contamination were generally low (1.3%); however, median Salmonella prevalence was found to be greater in subiliac LNs of feedlot cattle (11.8%) compared to those of cull cattle (0.65%). Enumeration analysis of a subset of 618 feedlot cattle LNs showed that 67% of those harboring S. enterica (97 of 144) did so at concentrations ranging from \u3c 0.1 to 1.8 log10 CFU/g, while 33% carried a higher burden of S. enterica, with levels ranging from 1.9 to \u3e 3.8 log10 CFU/g. Serotyping of S. enterica isolated identified 24 serotypes, with the majority being Montevideo (44.0%) and Anatum (24.8%). Antimicrobial susceptibility phenotypes were determined for all isolates, and the majority (86.1%) were pansusceptible; however, multidrug-resistant isolates (8.3%) were also occasionally observed. As Salmonella contained within LNs are protected from carcass interventions, research is needed to define opportunities for mitigating the risk of Salmonella contamination in LNs of apparently healthy cattle

Engineered metal oxide nanomaterials inhibit corneal epithelial wound healing in vitro and in vivo.

Ocular exposure to metal oxide engineered nanomaterials (ENMs) is common as exemplified by zinc oxide (ZnO), a major constituent of sunscreens and cosmetics. The ocular surface that includes the transparent cornea and its protective tear film are common sites of exposure for metal ENMs. Despite the frequency of exposure of the ocular surface, there is a knowledge gap regarding the effects of metal oxide ENMs on the cornea in health and disease. Therefore, we studied the effects of metal oxide ENMs on the cornea in the presence or absence of injury. Cell viability of immortalized human corneal epithelial (hTCEpi) cells was assessed following treatment with 11 metal oxide ENMs with a concentration ranging from 0.5 to 250 μg/mL for 24 hours. An epithelial wound healing assay with a monolayer of hTCEpi cells was then performed using 11 metal oxide ENMs at select concentrations based on data from the viability assays. Subsequently, based on the in vitro results, in vivo testing of precorneal tear film (PTF) quantity and stability as well as a corneal epithelial wound healing were tested in the presence or absence ZnO or vanadium pentoxide (V2O5) at a concentration of 50 μg/mL. We found that WO3, ZnO, V2O5 and CuO ENMs significantly reduced hTCEpi cell viability in comparison to vehicle control or the other metal oxide ENMs tested. Furthermore, ZnO and V2O5 ENMs also significantly decreased hTCEpi cell migration. Although ZnO and V2O5 did not alter PTF parameters of rabbits in vivo, corneal epithelial wound healing was significantly delayed by topical ZnO while V2O5 did not alter wound healing. Finally, hyperspectral images confirmed penetration of ZnO and V2O5 through all corneal layers and into the iris stroma. Considering the marked epithelial toxicity and corneal penetration of ZnO, further investigations on the impact of this ENM on the eye are warranted