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

Characterization of attachment differences of Shiga toxin-producing Escherichia coli (STEC) to pre-chill and post-chill beef tissues

Shiga toxin-producing Escherichia coli (STEC) has been implicated in beef-related foodborne illness outbreaks. Environmental factors influence bacterial attachment on beef and understanding of bacterial attachment may inform future innervations at the abattoir. This study measured STEC attachment under simulated meat processing conditions on adipose and lean beef tissues. Beef brisket was purchased from a local grocer, and 50 cm2 adipose and lean tissue samples were obtained and stored overnight (18 h; 4ºC). The following day, half of the samples were heated to a surface temperature of 30ºC while the remaining samples were maintained at 4ºC prior to inoculation with 150 µL STEC cocktail (O26, O45, O103, O111, O121, O145, and O157:H7; ca. 7 log CFU/mL) onto the meat surface. Samples were stored at 4⁰C 30 min after inoculation and enumerated at times 0, 3, 5, and 20 min and 1, 3, 8, 12, 24 and 48 h by spread plating loosely attached cells (buffer) and firmly attached cells (homogenized sample) on MacConkey Agar. At every sampling point, each meat sample was shaken for 90 s in a stomacher bag with 0.1% peptone water (PW), transferred into a second stomacher bag with fresh PW, and homogenized. Time*sample type (buffer vs. homogenized sample) was significant (P≤0.001), as STEC cells steadily became more firmly attached throughout the 48 h storage period. Sample type*meat type was statistically significant (P =0.0020) indicating a difference in loose vs. firmly attached populations on lean and adipose tissues; however, the largest difference observed was 0.22 log10 CFU/g. These data demonstrate that the firmly attached STEC population steadily increases on lean and adipose beef tissues over time. Future research should investigate if an increase in firmly attached STEC cells is correlated to reduced intervention efficacy on post-chill carcasses and subprimal cuts, as commonly observed

Attachment of Shiga Toxin-Producing Escherichia coli (STEC) to Pre-Chill and Post-Chill Beef Brisket Tissue

Shiga toxin-producing Escherichia coli (STEC) has caused numerous foodborne illness outbreaks where beef was implicated as the contaminated food source. Understanding how STEC attach to beef surfaces may inform effective intervention applications at the abattoir. This simulated meat processing conditions to measure STEC attachment to adipose and lean beef tissue. Beef brisket samples were warmed to a surface temperature of 30 °C (warm carcass), while the remaining samples were maintained at 4 °C (cold carcass), prior to surface inoculation with an STEC cocktail (O26, O45, O103, O111, O121, O145, and O157:H7). Cocktails were grown in either tryptic soy broth (TSB) or M9 minimal nutrient medium. Loosely and firmly attached cells were measured at 0, 3, 5, and 20 min and 1, 3, 8, 12, 24 and 48 h. TSB-grown STEC cells became more firmly attached throughout storage and a difference in loosely versus firmly attached populations on lean and adipose tissues was observed. M9-grown STEC demonstrated a 0.2 log10 CFU/cm2 difference in attachment to lean versus adipose tissue and variability in populations was recorded throughout sampling. Future research should investigate whether a decrease in intervention efficacy correlates to an increase in firmly attached STEC cells on chilled carcasses and/or subprimals, which has been reported

Attachment of Shiga Toxin-Producing <i>Escherichia coli</i> (STEC) to Pre-Chill and Post-Chill Beef Brisket Tissue

Shiga toxin-producing Escherichia coli (STEC) has caused numerous foodborne illness outbreaks where beef was implicated as the contaminated food source. Understanding how STEC attach to beef surfaces may inform effective intervention applications at the abattoir. This simulated meat processing conditions to measure STEC attachment to adipose and lean beef tissue. Beef brisket samples were warmed to a surface temperature of 30 °C (warm carcass), while the remaining samples were maintained at 4 °C (cold carcass), prior to surface inoculation with an STEC cocktail (O26, O45, O103, O111, O121, O145, and O157:H7). Cocktails were grown in either tryptic soy broth (TSB) or M9 minimal nutrient medium. Loosely and firmly attached cells were measured at 0, 3, 5, and 20 min and 1, 3, 8, 12, 24 and 48 h. TSB-grown STEC cells became more firmly attached throughout storage and a difference in loosely versus firmly attached populations on lean and adipose tissues was observed. M9-grown STEC demonstrated a 0.2 log10 CFU/cm2 difference in attachment to lean versus adipose tissue and variability in populations was recorded throughout sampling. Future research should investigate whether a decrease in intervention efficacy correlates to an increase in firmly attached STEC cells on chilled carcasses and/or subprimals, which has been reported

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 (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

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 &lsquo;no detectable generic Escherichia coli&rsquo; 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 &deg;C, inoculated with 5 logs per mL of non-pathogenic (generic) E. coli, and treated with Cl 25 &plusmn; 2 ppm, PAA 75 &plusmn; 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 (&lt;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