Whole genome sequencing confirms source of pathogens associated with bacterial foodborne illness in pets fed raw pet food

Co-resistance to methicillin and clindamycin among coagulase-negative staphylococci isolates recovered from pet food in Brazil

Pet food have been considered as possible vehicles of bacterial pathogens. The sudden boom of the pet food industry due to the worldwide increase in companion animal ownership calls for pet food investigations. Herein, this study aimed to determine the frequency, antimicrobial susceptibility profile, and molecular characteristics of coagulase-negative staphylococci (CoNS) in different pet food brands in Brazil. Eighty-six pet food packages were screened for CoNS. All isolates were identified at species level by MALDI-TOF MS and species-specific PCR. Antimicrobial susceptibility testing was performed by disc diffusion and broth microdilution (vancomycin and teicoplanin only) methods. The D-test was used to screen for inducible clindamycin phenotype (MLS-B). SCCmec typing and detection of mecA, vanA, vanB, and virulence-encoding genes were done by PCR. A total of 16 (18.6 %) CoNS isolates were recovered from pet food samples. Isolates were generally multidrug-resistant (MDR). All isolates were completely resistant (100 %) to penicillin. Resistances (12.5 % - 75 %) were also observed for fluoroquinolones, sulfamethoxazole-trimethoprim, tetracycline, rifampicin, erythromycin, and tobramycin. Isolates were susceptible to vancomycin (MICs <0.25-1 μg/mL) and teicoplanin (MICs <0.25-4 μg/mL). Intriguingly, 3/8 (37.5 %) CoNS isolates with the ERYRCLIS antibiotype expressed MLS-B phenotype. All isolates harboured blaZ gene. Seven (43.8 %) isolates carried mecA; and among them, the SCCmec Type III was the most frequent (n = 5/7; 71.4 %). Isolates also harboured seb, see, seg, sej, sem, etb, tsst, pvl, and hla toxin virulence-encoding genes (6.3 % - 25 %). A total of 12/16 (75 %) isolates were biofilm producers, while the icaAB gene was detected in an S. pasteuri isolate. Herein, it is shown that pet food is a potential source of clinically important Gram-positive bacterial pathogens. To the best of our knowledge, this is the first report of MLS-B phenotype and MR-CoNS in pet food in Latin America.

Raw meat-based diet for pets: a neglected source of human exposure to Salmonella and pathogenic Escherichia coli clones carrying mcr, Portugal, September 2019 to January 2020

BackgroundThe pet industry is expanding worldwide, particularly raw meat-based diets (RMBDs). There are concerns regarding the safety of RMBDs, especially their potential to spread clinically relevant antibiotic-resistant bacteria or zoonotic pathogens.AimWe aimed to investigate whether dog food, including RMBD, commercially available in Portugal can be a source of Salmonella and/or other Enterobacteriaceae strains resistant to last-line antibiotics such as colistin.MethodsFifty-five samples from 25 brands (21 international ones) of various dog food types from 12 suppliers were screened by standard cultural methods between September 2019 and January 2020. Isolates were characterised by phenotypic and genotypic methods, including whole genome sequencing and comparative genomics.ResultsOnly RMBD batches were contaminated, with 10 of 14 containing polyclonal multidrug-resistant (MDR) Escherichia coli and one MDR Salmonella. One turkey-based sample contained MDR Salmonella serotype 1,4,[5],12:i:- ST34/cgST142761 with similarity to human clinical isolates occurring worldwide. This Salmonella exhibited typical antibiotic resistance (bla TEM + strA-strB + sul2 + tet(B)) and metal tolerance profiles (pco + sil + ars) associated with the European epidemic clone. Two samples (turkey/veal) carried globally dispersed MDR E. coli (ST3997-complexST10/cgST95899 and ST297/cgST138377) with colistin resistance (minimum inhibitory concentration: 4 mg/L) and mcr-1 gene on IncX4 plasmids, which were identical to other IncX4 circulating worldwide.ConclusionSome RMBDs from European brands available in Portugal can be a vehicle for clinically relevant MDR Salmonella and pathogenic E. coli clones carrying genes encoding resistance to the last-line antibiotic colistin. Proactive actions within the One Health context, spanning regulatory, pet-food industry and consumer levels, are needed to mitigate these public health risks.

Genome-wide association study between copy number variation and feeding behavior, feed efficiency, and growth traits in Nellore cattle

BACKGROUND

Feeding costs represent the largest expenditures in beef production. Therefore, the animal efficiency in converting feed in high-quality protein for human consumption plays a major role in the environmental impact of the beef industry and in the beef producers' profitability. In this context, breeding animals for improved feed efficiency through genomic selection has been considered as a strategic practice in modern breeding programs around the world. Copy number variation (CNV) is a less-studied source of genetic variation that can contribute to phenotypic variability in complex traits. In this context, this study aimed to: (1) identify CNV and CNV regions (CNVRs) in the genome of Nellore cattle (Bos taurus indicus); (2) assess potential associations between the identified CNVR and weaning weight (W210), body weight measured at the time of selection (WSel), average daily gain (ADG), dry matter intake (DMI), residual feed intake (RFI), time spent at the feed bunk (TF), and frequency of visits to the feed bunk (FF); and, (3) perform functional enrichment analyses of the significant CNVR identified for each of the traits evaluated.

RESULTS

A total of 3,161 CNVs and 561 CNVRs ranging from 4,973 bp to 3,215,394 bp were identified. The CNVRs covered up to 99,221,894 bp (3.99%) of the Nellore autosomal genome. Seventeen CNVR were significantly associated with dry matter intake and feeding frequency (number of daily visits to the feed bunk). The functional annotation of the associated CNVRs revealed important candidate genes related to metabolism that may be associated with the phenotypic expression of the evaluated traits. Furthermore, Gene Ontology (GO) analyses revealed 19 enrichment processes associated with FF.

CONCLUSIONS

A total of 3,161 CNVs and 561 CNVRs were identified and characterized in a Nellore cattle population. Various CNVRs were significantly associated with DMI and FF, indicating that CNVs play an important role in key biological pathways and in the phenotypic expression of feeding behavior and growth traits in Nellore cattle.

An investigation of the presence and antimicrobial susceptibility of Enterobacteriaceae in raw and cooked kibble diets for dogs in the United Kingdom

Raw meat diets (RMD) for dogs are an increasingly popular alternative pet food choice, however studies worldwide have demonstrated them to be contaminated with zoonotic and antimicrobial resistant (AMR) bacteria, including bacteria resistant to critically important antibiotics. Despite this, few data exist surrounding the presence of these bacteria in RMD in the United Kingdom. The present study aimed to identify the most commonly selected RMD and non-raw diets (NRMD) by United Kingdom dog owners. Additionally, it investigated the presence of AMR-Enterobacteriaceae in samples of pre-prepared RMD and cooked commercial kibble dog foods. An online survey investigating diet preferences of United Kingdom dog owners was open for 6 weeks between February-March 2020. From this, the top 10 brands of pre-prepared raw and cooked kibble diets were ascertained and 134 samples purchased (110 RMD, 24 kibble) and subjected to microbiological testing. Bacterial enumeration of E. coli and other Enterobacteriaceae was undertaken, and the presence of Salmonella spp. and AMR-E. coli within samples determined. Whole genome sequencing was undertaken on Salmonella spp. and third-generation cephalosporin-resistant 3GCR-E. coli isolates. Pre-prepared RMD was most commonly selected by dog owners who fed RMD, and cooked commercial complete dry food was most frequently fed by owners who fed NRMD. Damaged and leaking packaging was observed in samples of RMD, alongside variability in information provided surrounding product traceability. Counts of E. coli and other Enterobacteriaceae exceeding >5,000 CFU/g were identified in samples of RMD. AMR-, extended-spectrum beta-lactamase (ESBL)-producing and 3GCR-E. coli was isolated from 39, 14 and 16% of RMD samples, respectively. Multiple antimicrobial resistance genes were identified in 3GCR-E. coli isolates. Of the ESBL encoding genes, blaCTX-M-15 was most commonly identified. S. enterica was isolated from 5% of RMD samples. No Enterobacteriaceae were isolated from any of the cooked kibble samples. The present study suggests that pre-prepared RMD available for dogs in the United Kingdom can be contaminated with zoonotic and AMR-Enterobacteriaceae. RMDs, therefore, are potentially an important One Health concern. Veterinary and medical professionals, pet food retailers and pet owners should be aware of these risks; and stringent hygiene measures should be practiced if owners choose to feed RMD.

Antimicrobial-Resistant Escherichia coli, Enterobacter cloacae, Enterococcus faecium, and Salmonella Kentucky Harboring Aminoglycoside and Beta-Lactam Resistance Genes in Raw Meat-Based Dog Diets, USA

The practice of feeding raw meat-based diets to dogs has grown in popularity worldwide in recent years. However, there are public health risks in handling and feeding raw meat-based dog diets (RMDDs) to dogs since there are no pathogen reduction steps to reduce the microbial load, which may include antimicrobial-resistant pathogenic bacteria. A total of 100 RMDDs from 63 suppliers were sampled, and selective media were used to isolate bacteria from the diets. Bacterial identification, antimicrobial susceptibility testing, and whole-genome sequencing (WGS) were conducted to identify antimicrobial resistance (AMR). The primary meat sources for RMDDs included in this study were poultry (37%) and beef (24%). Frozen-dry was the main method of product production (68%). In total, 52 true and opportunistic pathogens, including Enterobacterales (mainly Escherichia coli, Enterobacter cloacae) and Enterococcus faecium, were obtained from 30 RMDDs. Resistance was identified to 19 of 28 antimicrobials tested, including amoxicillin/clavulanic acid (23/52, 44%), ampicillin (19/52, 37%), cephalexin (16/52, 31%), tetracycline (7/52, 13%), marbofloxacin (7/52, 13%), and cefazolin (6/52, 12%). All 19 bacterial isolates submitted for WGS harbored at least one type of AMR gene. The identified AMR genes were found to mediate resistance to aminoglycoside (gentamicin, streptomycin, amikacin/kanamycin, gentamicin/kanamycin/tobramycin), macrolide, beta-lactam (carbapenem, cephalosporin), tetracycline, fosfomycin, quinolone, phenicol/quinolone, and sulfonamide. In conclusion, the results of this study suggest that feeding and handling RMDDs may pose a significant public health risk due to the presence of antimicrobial-resistant pathogens, and further research and intervention may be necessary to minimize these risks.

Systemic salmonellosis in 4 cats

Clinical signs in 4 cases of salmonellosis in cats included vomiting, diarrhea (2 cases each), fever, dystocia, icterus, and seizures (1 case each). Three cats died, and one was euthanized. Grossly, all cats were in poor body condition and had yellow-to-dark-red perianal feces (3 cases), oral and ocular pallor (2 cases) or icterus (1 case), fluid or pasty yellow intestinal contents (4 cases), white or dark-red-to-black depressed areas on the hepatic surface (2 cases), yellow abdominal fluid with swollen abdominal lymph nodes (1 case), and fibrin strands on the placental chorionic surface (1 case). Histologically, all cats had necrotizing enterocolitis and random hepatocellular necrosis. Other histologic findings included mesenteric (4 cases) or splenic (2 cases) lymphoid necrosis, and endometrial and chorioallantoic necrosis (1 case). Gram-negative bacilli were observed within neutrophils and macrophages in the intestinal lamina propria (4 cases), liver, spleen, lymph node, endometrium, and placenta (1 case each). Aerobic bacterial culture on frozen samples of small intestine, mesenteric lymph node, lung, and liver yielded Salmonella enterica subsp. enterica. Serotyping was consistent with S. Enteritidis (cases 1, 3) and S. Typhimurium (cases 2, 4).

Genomic features of mecA-positive methicillin-resistant Mammaliicoccus sciuri causing fatal infections in pets admitted to a veterinary intensive care unit

Methicillin-resistant staphylococci have become leading cause of infectious diseases in humans and animals, being categorized as high priority pathogens by the World Health Organization. Although methicillin-resistant Staphylococcus sciuri (recently moved to Mammaliicoccus sciuri) has been widely reported in companion animals, there is scarce information regarding their clinical impact and genomic features. Herein, we reported the occurrence and genomic characteristics of methicillin-resistant M. sciuri recovered from fatal infections in pets admitted to an intensive care unit of a veterinary hospital, in Brazil. Two M. sciuri strains were isolated from bronchoalveolar lavage samples collected from dog (strain SS01) and cat (strain SS02) presenting with sepsis and acute respiratory distress syndrome. Both isolates displayed a multidrug-resistant profile, whereas whole-genome sequencing analysis confirmed the presence of the mecA gene, along to genetic determinant conferring resistance to macrolides, streptogramins, aminoglycosides, and trimethoprim. For both strains, the mec and crr gene complex shared high identity (≥97%) with analogue sequences from a M. sciuri isolated from a human wound infection, in the Czech Republic. Strains were assigned to the sequence type ST52 and the novel ST74. Phylogenomic analysis revealed a broad host range association of these strains with several hosts and sources, including humans, animals, food, and the environment through different years and geographic locations. Our findings demonstrate that infections caused by mecA-positive M. sciuri strains can be a serious threat for veterinary intensive care patients and the medical staff, with additional implications for One Health approaches.

A Dog's Dinner: Factors affecting food choice and feeding practices for UK dog owners feeding raw meat-based or conventional cooked diets

INTRODUCTION

Food selection is an area of dog ownership where owners have direct control over their pet's wellbeing. While commercial cooked complete foods remain the majority component of many dog diets, there is increasing interest in alternative options including natural and raw ingredients. This study aimed to provide further data regarding feeding practices and diet choice for UK dog owners with a focus on raw meat diets.

METHODS

An online survey available to all UK dog owners and advertised through sources including social media and at Crufts was conducted from February to March 2020. Feeding practices and diet choice were assessed, and owners were categorised as either feeding a raw meat diet (RMD) or non-raw diet (NRMD) based on their responses. Descriptive, univariable and multivariable data analyses were undertaken to determine dog and owner factors associated with feeding RMD, and thematic analysis was undertaken on free-text responses.

RESULTS

A total of 1831 owners completed the survey (915 RMD, 916 NRMD) detailing information for 3212 dogs (1754 RMD, 1458 NRMD). Dog breed (German Shepherd), Border Collie, Crossbreed (p < 0.001), entire neuter status (p < 0.001) and younger age (p 0.022) were associated with RMD feeding. RMD-feeding owners were likely to own > 1 dog (p < 0.001). RMD-feeding owners were more likely to cite a 'more natural' diet as a reason for their diet choice, and less likely to cite 'advice from a veterinary professional' compared to those who fed NRMD (p < 0.001). They were more likely to seek dietary advice from social media, friends/family and breeders rather than a veterinary surgeon/nurse (p < 0.001). RMD-feeding owners perceived their diet choice to provide a wide range of health benefits, including for coat health, oral hygiene, general digestive system health, anal sac clearance, mobility, performance and behaviour, and perceived NRMD as a health risk for most of these health factors (p < 0.001). NRMD-feeding owners perceived RMD to be a risk for bone splinters and foreign bodies (p < 0.001). RMD-feeding owners did not perceive diet to be a risk to their dog, themselves or in-contact dogs or people. In contrast, NRMD-feeding owners perceived the opposite (p < 0.001).

CONCLUSIONS

Factors affecting dog food selection are multifactorial and complex, with owners who feed RMD and those who feed NRMD having differing views. Further research regarding benefits and risks of different diets is required, however it remains vital that communication regarding the public health risks of RMD is seen as credible to owners and disseminated in a way that reaches the desired audience.

UK dogs eating raw meat diets have higher risk of Salmonella and antimicrobial-resistant Escherichia coli faecal carriage

Objectives

To compare detection of Salmonella species and antimicrobial‐resistant Escherichia coli in the faeces of dogs eating raw meat or non‐raw diets and examine risk factors for their carriage.

Materials and Methods

Canine faecal samples (raw fed n=114; non‐raw fed n=76) were collected from May to July 2015 from across the UK. Enrichment and selective culture and biochemical and PCR assays were used to identify isolates. Escherichia coli underwent susceptibility testing to a range of antimicrobials, including third‐generation cephalosporins; PCR assays were used to detect antimicrobial‐resistant genes. Questionnaires were used to collect data on independent variables as risks for antimicrobial‐resistant (resistant to ≥1 tested antimicrobial), multi‐drug‐resistant (resistant to ≥3 antimicrobial classes) and third‐generation cephalosporin resistant Escherichia coli.

Results

Antimicrobial‐resistant, multi‐drug‐resistant and third‐generation cephalosporin resistant Escherichia coli were significantly more likely to be detected in raw fed (54, 25 and 31%, respectively) compared to non‐raw fed (17, 4 and 4%, respectively) dogs; Salmonella species were detected in eight (4%) raw fed dogs only.

Clinical Significance

Raw fed dogs may be a source of Salmonella species and Escherichia coli, resistant to highest priority critically important antimicrobials, representing a potential animal welfare and public health issue. Owners should be aware of the risks, especially households with members, both human and canine, who are very young, elderly or immunocompromised.

A Cross-Sectional Study of Knowledge on Ownership, Zoonoses and Practices among Pet Owners in Northern Portugal

Simple Summary

Pet ownership is common in most countries, but few published studies have addressed pet owners’ knowledge of zoonoses, pet contact practices, or awareness of zoonotic disease risks posed by pets. The aim of this study was to assess household knowledge, attitudes, and risks related to pet ownership and zoonoses in northern Portugal. A questionnaire was developed to gather information regarding participants’ demographic characteristics; household pet types and their importance to the family; pet contact-related attitudes; knowledge of zoonoses, high-risk groups, disease transmission pathways, and disease protection measures. It was observed that most participants considered pets an important part of the family. Nevertheless, high-risk practices were recurrent and pet owners’ knowledge was limited. These results reinforce the importance of further studies to better understand the existing gaps in knowledge of pet ownership and zoonoses and strengthens the need to adopt the One Health concept.

Abstract

Pet ownership is common in modern society. In Portugal, 38% and 31% of all households own at least one dog or cat, respectively. Few studies have ascertained the knowledge of pet owners on pet ownership and zoonoses, and none have been carried out in Portugal. The aim of the present study was to assess household knowledge and practices related to pet ownership and zoonoses in northern Portugal. A face-to-face questionnaire was completed by 424 pet owners, from November 2019 to February 2020. Most respondents (97.2%) considered pets as an important part of the family, especially women (p = 0.036); 73.1% allowed their pets to live an indoor/outdoor life; 41.3% denied sharing the bed with their pets while 29% assumed they did it daily; 20.3% reported never kissing their pets/pets licking their faces. Furthermore, 73.6% considered animals as potential sources of human diseases, but only 25.9% reported knowing the definition of zoonoses; 96.9% considered the role of veterinarians important in protecting public health. The low level of knowledge of pet owners and the occurrence of high-risk behaviors indicates a need to strengthen communication between veterinarians, physicians, pet owners, and the general public towards reduce the risk of acquisition and transmission of zoonoses.

The effects of raw-meat diets on the gastrointestinal microbiota of the cat and dog: a review

The aim of this review is to summarise the available literature on the effects of consuming raw, red meat diets on the gastrointestinal microbiome of the cat and dog. In recent years, feeding raw meat diets to cats and dogs has increased, in part associated with trends in human nutrition for "natural" and "species-appropriate" diets. These diets range from home-prepared unprocessed, nutritionally incomplete diets to complete and balanced diets with sterilisation steps in their manufacturing process. Feeding some formats of raw meat diets has been associated with nutritional inadequacies and zoonotic transfer of pathogens. The feeding of raw meat diets has been shown to alter the gastrointestinal microbiome of the cat and dog, increasing the relative abundances of bacteria associated with protein and fat utilisation, including members of the genera Fusobacterium and Clostridium. While in humans, these genera are more commonly known for members that are associated with disease, they are a diverse group that also contains harmless commensals that are a normal component of the gastrointestinal microbiota. Moreover, members of these genera are known to produce butyrate from protein and amino acid fermentation and contribute to intestinal homeostasis in raw meat-fed dogs and cats. Currently, only a limited number of studies have examined the impacts of raw meat diets on the cat and dog microbiota, with many of these being descriptive. Additional controlled and systems-based studies are required to functionally characterise the roles of key microbial groups in the metabolism of raw meat diets, and determine their impacts on the health and nutrition of the host.

Mixtures of natural antimicrobials can reduce Campylobacter jejuni, Salmonella enterica and Clostridium perfringens infections and cellular inflammatory response in MDCK cells

Background

The classification of natural antimicrobials as potential antibiotic replacements is still hampered by the absence of clear biological mechanisms behind their mode of action. This study investigated the mechanisms underlying the anti-bacterial effect of a mixture of natural antimicrobials (maltodextrin, citric acid, sodium citrate, malic acid, citrus extract and olive extract) against Campylobacter jejuni RC039, Salmonella enterica SE 10/72 and Clostridium perfringens ATCC® 13124 invasion of Madin–Darby Canine Kidney cells (MDCK).

Results

Minimum sub-inhibitory concentrations were determined for Campylobacter jejuni (0.25%), Salmonella enterica (0.50%) and Clostridium perfringens (0.50%) required for the in vitro infection assays with MDCK cells. The antimicrobial mixture significantly reduced the virulence of all three pathogens towards MDCK cells and restored the integrity of cellular tight junctions through increased transepithelial resistance (TEER) and higher expression levels of ZO-1 (zonula occludens 1) and occludin. This study also identified the ERK (external regulated kinase) signalling pathway as a key mechanism in blocking the pro-inflammatory cytokine production (IL-1β, IL-6, IL-8, TNF-α) in infected cells. The reduction in hydrogen peroxide (H₂O₂) production and release by infected MDCK cells, in the presence of the antimicrobial mixture, was also associated with less tetrathionate formed by oxidation of thiosulphate (p < 0.0001).

Conclusion

The present study describes for the first time that mixtures of natural antimicrobials can prevent the formation of substrates used by bacterial pathogens to grow and survive in anaerobic environments (e.g. tetrathionate). Moreover, we provide further insights into pathogen invasion mechanisms through restoration of cellular structures and describe their ability to block the ERK–MAPK kinase pathway responsible for inflammatory cytokine release

Effects of autoclaving on compressive strength of bovine bones and their use as chewing agents for dogs

This study aimed to evaluate the effect of autoclave processing on compressive stress of spongy and cortical bones, and the effect of autoclaved bones as chewing agents to reduce dental calculus in adult dogs. Spongy and cortical bones were autoclaved (1 ATM, 30 min, and 120°C) and compressive strength was evaluated in autoclaved and raw bone specimens. Autoclaved bones were offered to ten Beagle dogs divided into two groups of 5 dogs each: Group 1 – received a portion of the autoclaved bovine cortical bone (ACB) and Group 2 – received a portion of the autoclaved bovine spongy bone (ASB). Prior to the experimental period (1-d) and every two days thereafter, oral photographs were taken on both sides of the dental arch to evaluate dental calculus reduction over time. The vestibular surface of the canines, premolars, and molars teeth was evaluated using integration software to measure the proportion between the area covered by calculus and the total teeth area. The effect of bone type, treatment (raw vs. autoclaved), and their interaction were evaluated using the PROC GLIMMIX procedure of SAS (version 9.4). Linear equations were generated to estimate calculus reduction over time for ACB and ASB. Compressive strength was higher (P < 0.05) in cortical bones compared to spongy bones. However, the autoclaving procedure did not affect (P > 0.05) compressive strength, regardless of the bone type. The teeth area covered by calculus of dogs that were offered ACB reduced from 41% to 32% in 5 days, and at the end of 15 days a reduction of 62.2% was observed, resulting in a remaining of 15.5% of teeth area covered by calculus. In this group, the dental calculus area reduced by 57.7% after 5 days, and at the end of the trial, only 5.4% of teeth were still covered by calculus, which represents a reduction of 81%. The linear regression analysis revealed no significant difference between the slopes for the ACB and ASB equations (P > 0.05). No health complications such as tooth fracture, intestinal obstructions, and oral lesions were observed throughout the study. Our results demonstrated that the autoclave processing did not impair compressive strength of spongy and cortical bones. This corroborates with the results observed in vivo, which suggests that autoclaved bones are chewing agents for adult dogs with additional benefits of lower risk of bacterial contamination.

Rapid Screening for Salmonella in Raw Pet Food by Loop-Mediated Isothermal Amplification

ABSTRACT

Raw pet food, composed of raw meat and vegetables, has increased in popularity in recent years. Multiple surveys and frequent recalls indicate that this commodity has a high risk of contamination with Salmonella and other foodborne pathogens. Improved screening methods are needed to meet the growing demand for testing. This matrix verification study aimed to apply a Salmonella loop-mediated isothermal amplification (LAMP) method, recently completed multilaboratory validation in dry dog food, in several raw pet food matrices, following the U.S. Food and Drug Administration (FDA)'s method validation guidelines. Five types of raw pet food, consisting of freeze-dried beef and chicken treats and frozen beef, pork, and turkey complete foods, were evaluated. For each matrix, two sets of ten 25-g test portions (seven inoculated with ≤30 cells of Salmonella Typhimurium and three uninoculated controls) were examined. One set was preenriched in buffered peptone water and the other one was preenriched in lactose broth, which was followed by LAMP screening using two isothermal master mixes (ISO-001 and ISO-004). All results were confirmed by culture as specified in the FDA Bacteriological Analytical Manual (BAM). The LAMP method accurately detected Salmonella in all inoculated test portions of the five raw pet food samples, regardless of the preenrichment broth used. Positive results could be obtained within 4 min of the LAMP run using the ISO-004 master mix. All uninoculated controls tested negative using LAMP or BAM. In addition, one turkey-based complete pet food sample was found to be already contaminated with three Salmonella serovars harboring multiple antimicrobial resistance genes. The Salmonella LAMP method offers a rapid, reliable, and robust tool for routine screening of Salmonella in raw pet food, which will help better ensure product safety and protect public health.

HIGHLIGHTS

A Survey among Dog and Cat Owners on Pet Food Storage and Preservation in the Households

BACKGROUND

Pet food storage plays a crucial role in maintaining the nutritional and sensory properties of purchased products over time.

METHODS

An online survey was developed to collect data regarding owners' storage habits for both commercial and home-made diets.

RESULTS

The questionnaire was completed by 1545 dog owners and 676 cat owners. Pet and owner age played roles in the choice of the type of diet (commercial vs. home-cooked vs. raw meat-based) adopted. Kibble feeders (75.7%) usually bought one (50.1%) or two (24.6%) packages at a time, and most pets (64.4%) took a minimum four weeks to consume an entire bag. Almost half of the owners (43.5%) used a container to store pet food (plastic bins for 79.5%). Pet food was commonly stored in the kitchen (45.1%) and not exposed to direct light (94.5%); 23.6% of the kibble feeders said it might be exposed to high temperatures. Most commercial pet food feeders (67.3%) considered preservatives a potential health risk for pets. Among homemade diet feeders, 38.6% stored fish oil at room temperature.

CONCLUSIONS

Pet owners should be educated in proper food storage management when receiving feeding instructions from veterinarians. More comprehensive information on the nature and importance of additives in pet food should be promoted by manufacturers.

Systemic Listeria monocytogenes infection and concurrent pleural mesothelioma in a cat

Herein we describe a rare case of systemic Listeria monocytogenes infection with concurrent pleural mesothelioma in a stray cat that was found dead and submitted for autopsy. Gross pathology changes consisted of thoracic clear yellow fluid admixed with suspended fibrin strands; clear-to-tan, variably sized, <3 mm diameter pulmonary nodules; and enlargement of the submandibular, retropharyngeal, and prescapular lymph nodes. Histologic changes consisted of extensive areas of suppurative inflammation and necrosis with mineralization that partially effaced the pulmonary parenchyma and lymph nodes. Random, distinct necrotic foci were present throughout the hepatic parenchyma. Extending from the pleura, within perinecrotic alveolar spaces, and infiltrating the submandibular, retropharyngeal, and prescapular lymph nodes were dense sheets of neoplastic epithelioid cells with moderate pleomorphism and occasional karyomegaly and multinucleation. Neoplastic cells exhibited immunolabeling for pancytokeratin AE1/AE3 and vimentin, consistent with pleural mesothelioma. Aerobic bacterial culture of lung yielded heavy growth of L. monocytogenes. Immunohistochemistry (IHC) for L. monocytogenes revealed clusters of bacteria in the lung, lymph node, and liver. Pathologic changes were consistent with systemic listeriosis, confirmed by bacterial culture and IHC, and concurrent pleural mesothelioma.

Antibiotic resistance: bioinformatics-based understanding as a functional strategy for drug design

The use of antibiotics to manage infectious diseases dates back to ancient civilization, but the lack of a clear distinction between the therapeutic and toxic dose has been a major challenge. This precipitates the notion that antibiotic resistance was from time immemorial, principally because of a lack of adequate knowledge of therapeutic doses and continuous exposure of these bacteria to suboptimal plasma concentration of antibiotics. With the discovery of penicillin by Alexander Fleming in 1924, a milestone in bacterial infections' treatment was achieved. This forms the foundation for the modern era of antibiotic drugs. Antibiotics such as penicillins, cephalosporins, quinolones, tetracycline, macrolides, sulphonamides, aminoglycosides and glycopeptides are the mainstay in managing severe bacterial infections, but resistant strains of bacteria have emerged and hampered the progress of research in this field. Recently, new approaches to research involving bacteria resistance to antibiotics have appeared; these involve combining the molecular understanding of bacteria systems with the knowledge of bioinformatics. Consequently, many molecules have been developed to curb resistance associated with different bacterial infections. However, because of increased emphasis on the clinical relevance of antibiotics, the synergy between in silico study and in vivo study is well cemented and this facilitates the discovery of potent antibiotics. In this review, we seek to give an overview of earlier reviews and molecular and structural understanding of bacteria resistance to antibiotics, while focusing on the recent bioinformatics approach to antibacterial drug discovery.

Understanding the evolution of antibiotic resistance at the molecular level as a functional tool for bioinformatic-based drug design.