Publications by authors named "Richard Pereira"

One Health is an integrative approach that emphasizes the interconnectedness of human, animal, and environmental health, advocating for collaborative, multidisciplinary efforts to address health challenges, particularly amid globalization and emerging threats. This paper examines the integration of One Health principles into global health education, highlighting the importance of interdisciplinary collaboration and innovative pedagogical approaches. It evaluates various teaching methods, including problem-based learning (PBL), team-based learning (TBL), simulation-based education (SBE), case-based learning (CBL), interdisciplinary workshops and seminars (IWS), and service-learning (SL), analyzing their strengths and weaknesses in fostering interdisciplinary understanding and practical application of One Health concepts.

View Article and Find Full Text PDF

Perovskite nanocrystals hold significant promise for a wide range of applications, including solar cells, LEDs, photocatalysts, humidity and temperature sensors, memory devices, and low-cost photodetectors. Such technological potential stems from their exceptional quantum efficiency and charge carrier conduction capability. Nevertheless, the underlying mechanisms of photoexcitation, such as phase segregation, annealing, and ionic diffusion, remain insufficiently understood.

View Article and Find Full Text PDF

has been attributed to playing a major role in a cascade of events that affect the prevalence and severity of uterine disease in cattle. The objectives of this project were to (i) define the association between the prevalence of specific antimicrobial resistance and virulence factor genes in with the clinical status related to uterine infection, (ii) identify the genetic relationship between isolates from cows with diarrhea, with mastitis, and with and without metritis, and (iii) determine the association between the phenotypic and genotypic antimicrobial resistance identified on the isolated from postpartum cattle. Bacterial isolates ( = 148) were obtained from a larger cross-sectional study.

View Article and Find Full Text PDF

For this study, antimicrobial susceptibility data for enterica subsp. enterica serovar Dublin (S. Dublin)-a well-known cattle-adapted pathogen with current concerns for multidrug resistance-were recovered from cattle at the California Animal Health and Food Safety Laboratory System (CAHFS) over the last three decades (1993-2019) and were evaluated using tools to capture diversity in antimicrobial resistance.

View Article and Find Full Text PDF

Accurate isolation and identification of pathogens for an animal with bovine respiratory disease are of critical importance to direct appropriate decision-making related to the treatment of individual animals, as well as control and prevention options in a herd setting. The objective of this study was to compare nasopharyngeal sampling approaches to evaluate accuracy and agreement for the recovery of (MH) and (PM) from deep nasopharyngeal swabs (DNS) using 3 different swabs. Deep nasopharyngeal samples were collected from 45 dairy calves using 3 swabs: (1) double-guarded culture swab (DGS); (2) single-guarded culture swab (SGS); and (3) unguarded culture swab (UGS).

View Article and Find Full Text PDF
Article Synopsis
  • This study aimed to identify changes in vaginal discharge metabolites in dairy cows to predict metritis development and its treatment outcomes.
  • Conducted on two dairies in California and Texas, vaginal discharge was collected from cows at various stages post-calving, and metritis was diagnosed based on specific discharge characteristics.
  • The analysis revealed significant differences in metabolite levels between cows with metritis and those without, pinpointing specific metabolites tied to both the onset and cure of the condition.
View Article and Find Full Text PDF
Article Synopsis
  • - The study aimed to analyze the microbial diversity in the uterus of post-partum dairy cows with and without metritis using shotgun metagenomics, focusing on samples from 24 California dairy farms and categorizing cows into three groups: control (CT), metritis (MET), and purulent discharge (PUS) based on vaginal discharge characteristics.
  • - The results indicated that while all three groups had high microbial diversity, cows with metritis (MET) and purulent discharge (PUS) showed lower alpha diversity compared to the control group (CT), and significant differences in microbial diversity were found between CT and MET groups.
  • - Specific genera such as Bacteroides and Clostridium were found to be more abundant in the met
View Article and Find Full Text PDF

Antimicrobial use in food-producing animals is under increasing scrutiny due to the potential effect on the selection of antimicrobial-resistant bacteria that may be transmitted to humans by direct contact, with the food chain, or the environment. Novel data monitoring commensal Escherichia coli from dairy farms is essential for understanding antimicrobial resistance (AMR) patterns and their association with herd health management practices. The objectives of this study were to: (1) compare the prevalence of antimicrobial resistance in the E.

View Article and Find Full Text PDF

Silver nanoparticles (AgNPs) exhibit very interesting properties that have been employed in several kinds of applications spanning from antibacterial activity to plasmon-polaritons generation. Nanoparticle size strongly influences these applications. However, the characterization of ultrasmall AgNPs (particle diameter < 10 nm) encompassing different aspects such as average size, polydispersion, shape (anisotropy), concentration, and density remains a challenging task.

View Article and Find Full Text PDF

Appropriate sample collection, storage conditions, and time for transport to the laboratory are important for an accurate diagnostic result. We evaluated the effects of transport storage medium type, time of storage, and storage temperatures on (MH) and (PM) recovery using an in vitro model simulation. A quantitative culture method, using colony-forming units per milliliter, was used to recover MH or PM by an in vitro model with cotton swabs.

View Article and Find Full Text PDF

Dairy farmworkers are commonly responsible for disease diagnosis and routine treatment decisions for cattle. This highlights the importance of farmworkers' knowledge and skills to successfully implement judicious use of antimicrobials in livestock production systems. The main objectives of this project were to develop and evaluate an on-farm educational program for farmworkers in antimicrobial stewardship in adult dairy cattle.

View Article and Find Full Text PDF

Antimicrobials are necessary for the treatment of bacterial infections in animals, but increased antimicrobial resistance (AMR) is becoming a concern for veterinarians and livestock producers. This cross-sectional study was conducted on cow-calf operations in northern California to assess prevalence of AMR in and spp. shed in feces of beef cattle of different life stages, breeds, and past antimicrobial exposures and to evaluate if any significant factors could be identified that are associated with AMR status of the isolates.

View Article and Find Full Text PDF
Article Synopsis
  • Backyard poultry and livestock farming has seen a surge in California due to a growing consumer preference for local and organic products, prompting a study on farmers' management practices and understanding of the Veterinary Feed Directive (VFD) and California Senate Bill (SB) 27 for disease prevention and antibiotic use.
  • The study surveyed 242 backyard and small-scale livestock owners, primarily raising chickens and small ruminants for personal use, and found that antibiotics were mainly used under veterinary guidance for treating sick animals.
  • Implementation of VFD and SB27 has encouraged responsible antibiotic use and improved collaboration between farmers and veterinarians, which could lead to better farming practices and a decrease in antimicrobial resistance risks in California.
View Article and Find Full Text PDF

Florfenicol is a broad-spectrum antibiotic commonly prescribed in an extra-label manner for treating meat and dairy goats. Scientific data in support of a milk withdrawal interval recommendation is limited to plasma pharmacokinetic data and minimal milk residue data that is limited to cattle. Therefore, a rapid residue detection test (RRDT) could be a useful resource to determine if milk samples are free of drug residues and acceptable for sale.

View Article and Find Full Text PDF

subsp. serovar () is a cattle-adapted pathogen that has emerged as one of the most commonly isolated and multidrug resistant (MDR) serovars in cattle. may be shed in feces, milk, and colostrum and persist in asymptomatic cattle, leading to spread and outbreaks in herds.

View Article and Find Full Text PDF

The goals of this study were to evaluate factors affecting recovery and antimicrobial resistance (AMR) in intrauterine E. coli in post-partum dairy cows with and without metritis from commercial California dairy farms. Using a cross-sectional study design, a total of 307 cows were sampled from 25 farms throughout California, from which a total of 162 intrauterine E.

View Article and Find Full Text PDF

This study used 16S rRNA sequencing to evaluate the effects of dry cow antimicrobial therapy on the udder milk microbiota by comparing the microbial populations in milk at dry-off (DRY) (~60 days before calving) and post-partum (FRESH) (4-11 days after calving) from cows receiving an intramammary antibiotic infusion prior to dry-off (IMT) and cows that did not receive treatment (CTL). Milk was collected from 23 cows from the IMT group and 27 cows from the CTL group. IMT and DRY samples had a greater correlation with the genera and , and the family Micrococcaceae, when compared to IMT and FRESH samples.

View Article and Find Full Text PDF

Although puerperal metritis (PM) is a common infectious disease in dairy cattle, there are currently discrepancies between clinical case definitions within and between available peer-reviewed literature and on-farms practices. The inconsistent use of PM criteria across studies and on-farms practices can result in disparities related to recommendations for treating cows, affecting judicious use of antimicrobials. The objective of this study was to systematically review the peer-reviewed literature for clinical signs used for case definition of PM.

View Article and Find Full Text PDF

Background: Antibiotic resistance genes (ARGs) are considered to be emerging environmental contaminants of concern potentially posing risks to human and animal health, and this research studied the prevalence of antimicrobial resistance in dairy manure.

Methods: This study is focused on investigating prevalence of ARGs in California dairy farm manure under current common different manure management. A total of 33 manure samples were collected from multiple manure treatment conditions: (1) flushed manure (FM), (2) fresh pile (FP), (3) compost pile (CP), (4) primary lagoon (PL), and (5) secondary lagoon (SL).

View Article and Find Full Text PDF

The objective of this study was to investigate the effect of the antimicrobial drugs (AMD) on the shedding of resistant Enterobacteriaceae in feces of pre-weaned dairy calves. The AMD considered were ceftiofur, administered parenterally, and neomycin sulfate added in milk replacer and fed to calves during the first 20 days of life. Fifty-five calves, aged one to three days, were enrolled and followed to 64 days.

View Article and Find Full Text PDF

The objectives of this study were to characterize overall genomic antibiotic resistance profiles of fecal and spp. from dairy cattle at different production stages using whole-genome sequencing and to determine the association between antimicrobial resistance (AMR) phenotypes and their corresponding genotypes. The Comprehensive Antibiotic Resistance Database (CARD) and ResFinder, two publicly available databases of antimicrobial resistance genes, were used to annotate isolates.

View Article and Find Full Text PDF

Antibiotic resistance genes (ARGs) are emerging contaminants causing serious global health concern. Interventions to address this concern include improving our understanding of methods for treating waste material of human and animal origin that are known to harbor ARGs. Anaerobic digestion is a commonly used process for treating dairy manure, and although effective in reducing ARGs, its mechanism of action is not clear.

View Article and Find Full Text PDF

Background: Understanding the effects of herd management practices on the prevalence of multidrug-resistant pathogenic and commensals spp. in dairy cattle is key in reducing antibacterial resistant infections in humans originating from food animals. Our objective was to explore the herd and cow level features associated with the multi-drug resistant, and resistance phenotypes shared between , and spp.

View Article and Find Full Text PDF

The California (CA) dairy industry was surveyed in July 2017 to evaluate producers' knowledge and perceptions and antimicrobial drug (AMD) use in preweaned dairy calves following the implementation of the nationwide veterinary feed directive final rule (VFD) in January 2017 and prior to statewide implementation of CA Senate Bill (SB) 27 in January 2018. Together, these regulations require veterinary oversight for all uses of medically important antimicrobial drugs (MIADs) administered to livestock in CA. Survey questionnaire was mailed to 1,361 CA Grade A milk producing dairies and calf ranches across CA resulting in a 12% (169) response.

View Article and Find Full Text PDF

The objectives of this study were to evaluate the prevalence of extended spectrum β-lactamase (ESBL) genes, AmpC-type β-lactamase (ACBL) genes, and plasmid mediated quinolone resistance (PMQR) genes in isolated at a Veterinary Medical Teaching Hospital microbiology laboratory, examine trends in presence of these resistance genes, and to explore the correlation between phenotypic resistance and presence of specific genes. The presence of ESBL, ACBL, and PMQR genes were detected using a single, novel multiplex qPCR. Only the genes and were detected in the 110 isolates tested.

View Article and Find Full Text PDF