Prevalence and antimicrobial resistance of Salmonella isolated from conventional and antimicrobial-free (ABF) swine herds in North Carolina

The main objective of this stdy was to compare prevalence and antimicrobial resistance of Salmonella isolated from swine reared in antimicrobial-free (ABF) and conventional production systems in North Carolina

Comparison of multidrug resistant Salmonella between intensively - and extensively-reared antimicrobial - free (ABF) swine herds

This cross-sectional study was conducted to determine the prevalence and antimicrobial resistance of Salmonella species in swine reared in the intensive (indoor) and extensive (outdoor) ABF production systems at farm and slaughter in North Carolina, U.S.A. We sampled a total of 279 pigs at farm (Extensive 107; Intensive 172) and collected 274 carcass swabs (Extensive 124; Intensive 150) at slaughter. Salmonella species were tested for their susceptibility against 12 antimicrobial agents using the Kirby-Bauer disk diffusion method. Serogrouping was done using polyvalent and group specific antisera. A total of 400 salmonellae were isolated in this study with a significantly higher Salmonella prevalence from the Intensive (30%) than the extensive farms (0.9%) (P \u3c 0.001 ). At slaughter, significantly higher Salmonella was isolated at the pre and post-evisceration stages from extensively (29 % pre-evisceration and 33.3 % post-evisceration) than the intensively (2 % pre-ev1sceration and 6 % post-evisceration) reared swine (P \u3c 0.001 ). The isolates were clustered in six serogroups including B, C, E1, E4, G and R. Highest frequency of antimicrobial resistance was observed against tetracycline (78.5%) and streptomycin (31 .5%). A total of 13 antimicrobial resistance patterns were observed including the pentaresistant strains with ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline resistance pattern observed only among isolates from the intensive farms (n=28) and all belonged to serogroup B. This study shows that multidrug resistant Salmonella are prevalent in ABF production systems despite the absence of antimicrobial selection pressure

Salmonella prevalence in pigs reared on farms with and without antimicrobials

A convenience sample of farms using antimicrobials (antimicrobial-using, AMU) post-weaning for therapy and/or growth promotion (n=21) were contrasted to a convenience sample of farms not using antimicrobials post-weaning (antimicrobial-free, AMF, n=21) distributed across three US geographic areas

Campylobacter prevalence and antimicrobial resistance in swine reared in antimicrobial-free and conventional production systems

The objective of this study was to determine and compare the prevalence and antimicrobial resistance of Campylobacter species in swine reared in the conventional and antimicrobial free production (ABF) production systems as part of a multi-state study. To date, 19 conventional and 16 ABF groups have been followed

Campylobacter Prevalence and Diversity in Antimicrobial Free and Conventionally Reared Market Swine

The objectives of this study were to determine the prevalence and antimicrobial resistance of Campylobacter spp. among pigs raised antimicrobial free (ABF) and those raised conventionally. Bacterial isolation was done on-farm and at slaughter using conventional methods and antimicrobial susceptibility tests were done for 12 antimicrobials using Kirby-Bauer and epsilometric test (E-test) methods. All 14 herds were positive for Campylobacter. On-farm prevalence among ABF herds was 71% and 81% among conventional herd. In contrast, the prevalence among carcass swabs was higher among ABF herds than conventional herds with 60% and 29% respectively. There was significant reduction after chilling in all groups (p\u3c0.05). On-farm frequency of antimicrobial resistance was significantly higher among isolates from conventional herds than ABF (p\u3c0.05). In contrast frequency of resistance to five of the seven antimicrobials was higher among carcass swabs of ABF herds than conventional herds

Prevalence and antimicrobial resistance profile of Campylobacter isolated from conventional and antibiotic free swine farms in three geographic locations

The prevalence and antimicrobial resistance of Campylobacter were examined from swine reared in conventional and antimicrobial-free (ABF) production systems in three geographical locations: North Carolina (NC), Ohio (OH) and Wisconsin (WI). Methods: A total of 1500 pigs and 1930 carcass swab samples were evaluated for the prevalence of Campylobacter. Fecal samples from 662 pigs from NC (370 conventional farms and 292 ABF farms), 379 from OH (268 conventional and 111 ABF) and 459 from WI (160 conventional and 299 ABF) were included. Antimicrobial susceptibility testing was performed using agar dilution method against a panel of six antimicrobials

Whole genome sequencing reveals widespread distribution of typhoidal toxin genes and VirB/D4 plasmids in bovine-associated nontyphoidal Salmonella

Aedes aegypti is the primary urban mosquito vector of viruses causing dengue, Zika and chikungunya fevers –for which vaccines and efective pharmaceuticals are still lacking. Current strategies to suppress arbovirus outbreaks include removal of larval-breeding sites and insecticide treatment of larval and adult populations. Insecticidal control of Ae. aegypti is challenging, due to a recent rapid global increase in knockdown-resistance (kdr) to pyrethroid insecticides. Widespread, heavy use of pyrethroid spacesprays has created an immense selection pressure for kdr, which is primarily under the control of the voltage-gated sodium channel gene (vgsc). To date, eleven replacements in vgsc have been discovered, published and shown to be associated with pyrethroid resistance to varying degrees. In Mexico, F1,534C and V1,016I have co-evolved in the last 16 years across Ae. aegypti populations. Recently, a novel replacement V410L was identifed in Brazil and its efect on vgsc was confrmed by electrophysiology. Herein, we screened V410L in 25 Ae. aegypti historical collections from Mexico, the frst heterozygote appeared in 2002 and frequencies have increased in the last 16 years alongside V1,016I and F1,534C. Knowledge of the specifc vgsc replacements and their interaction to confer resistance is essential to predict and to develop strategies for resistance management

Salmonella prevalence serotypes and patterns of antimicrobial resistance in cohorts of nursery and finishing pigs

Salmonella are now being monitored by the Food Safety Inspection Service of the USDA for purposes of process control in slaughter plants, and as a sentinel organism for emerging antimicrobial resistance (I). Public concerns about the emergence of foodborne bacteria with multi-resistant phenotypes, and about the use of antimicrobials in food animals, are increasing. Despite considerable research, the epidemiology of asymptomatic Salmonella in pigs is poorly understood (2). The purpose of this paper is to examine the association between nursery prevalence of Salmonella and finisher prevalence, and to describe patterns of antimicrobial use and antimicrobial resistant Salmonella in modern swine rearing facilities

Comparison of three methods for routine detection of staphylococcus aureus isolated from bovine mastitis

The present study aimed to compare three identification methods that are routinely used for the detection of Staphylococcus aureus as bovine mastitis agent. The evaluated methods were as followed: conventional biochemical method, commercial identification system BioLog (Gen III MicroPlate) and amplification of species-specific gene (nuc) by polymerase chain reaction (PCR). A total of 73 staphylococcal isolates were collected from 453 individual milk samples from dairy cows with subclinical and clinical mastitis from different farms in Bulgaria. This isolates were determined as 60 coagulase-positive, 3 catalase-negative and 10 coagulase-negative by conventional methods. BioLog system identified 72 isolates as S. аureus subsp. aureus and one coagulase-positive isolate as S. schleiferi subsp. coagulans. PCR amplification of nuc gene further confirmed S. аureus subsp. aureus isolates identified by the BioLog system. The primary identification of S. aureus on the basis of coagulase level led to erroneous determination of 14 (19.2%) of the isolates. Based on the findings, BioLog system and PCR appear to be more reliable detection systems for S. aureus from milk. In conclusion, the present study showed that a routine approach using a combination of phenotypic and molecular detection systems could improve S. aureus detection in milk

Association between biocide use and antimicrobial resistance of Salmonella in swine production environment

Swine are important reservoirs of antimicrobial resistant Salmonella. The emergence and dissemination of multidrug resistant (MDR) Salmonella enterica has also become a major concern globally. Studies on the association between biocide usc and emergence and persistence of MDR Salmonella in swine production environment are very limited. The aim of this study was to determine the role of specific classes of biocides (disinfectants) in the emergence and persistence of multidrug resistant Salmonella in swine production environments