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Bacteria of the genus Salmonella are highly adapted for the growth in both humans and animals and cause a wide spectrum of disease. The growth of Serotypes S. typhi and S. paratyphi is restricted to human hosts, in whom these organisms cause enteric (typhoid) fever. The remaining Serotypes (non typhoidal Salmonella or NTS) can colonize the gastrointestinal tracts of the broad range of animals, including mammals, reptiles, birds and insects. The usual clinical presentation of non-typhoidal salmonellae (NTS) infection is self limited gastroenteritis; however bacteremia and focal extra intestinal infection may occur. However salmonella localization to the skin presenting as cutaneous ulceration is regarded as a rare event. Rates of morbidity and mortality associated with NTS are highest among the elderly, infants, and immunocompromised individuals, including those with hemoglobinopathies, HIV infection, or infections that cause blockade of the reticuloendothelial system. We isolated S.infantis in 50 years old man with left leg cellulitis. The serotype was confirmed at Central Research Institute, Kasauli.

This matched case-control study investigated the risk factors for sporadic Salmonella Infantis infection in 263 affected children and 263 age-, gender- and neighbourhood-matched controls. Information about exposure to potential risk factors was obtained via telephone interview and evaluated by conditional logistic regression analysis. Age groups ⩽1 year (n = 77) and >1 year (n = 186) were analysed separately. Of those aged ⩽1 year, breastfeeding was a significant protective factor against infection [matched odds ratio (mOR) 0·24, 95% confidence interval (CI) 0·10–0·59, P < 0·01]. In the older group, consumption of eggs (mOR 1·87, 95% CI 1·00–3·49, P = 0·05) was a significant risk factor and thawing chicken in water (mOR 2·55, 95% CI 0·94–6·91, P = 0·07) was borderline risk factor, while consumption of carrots (mOR 0·46, 95% CI 0·26–0·83, P < 0·01), drinking tap water (mOR 0·44, 95% CI 0·22–0·85, P = 0·02), religious lifestyle (mOR 0·40, 95% CI 0·21–0·74, P < 0·01) and having a high number of children in the household (mOR 0·72, 95% CI 0·58–0·88, P < 0·01) were significant protective factors. Consumers should avoid eating undercooked eggs and food handlers should be educated regarding proper handling and cooking of eggs. Breastfeeding should be strongly encouraged by public health authorities. The public must be educated on stringent hygiene practices, especially proper cooking of eggs to reduce infection rates. [ABSTRACT FROM PUBLISHER]

Highlights: [•] The genetic relationship of S. Infantis from human and food origin was investigated. [•] The strains presented a high genetic similarity by ERIC-PCR, PFGE and MLST. [•] Almost all the strains harbored all the virulence markers searched. [•] A prevalent subtype may have been causing disease and contaminating food in Sao Paulo State. [•] Better control measures for S. Infantis are needed in Brazil. [ABSTRACT FROM AUTHOR]

Salmonella Infantis is presenting an increasing risk to public health. Of particular concern are the reports of pESI, a multidrug resistance (MDR) encoding megaplasmid, in isolates from multiple countries, but little is known about its presence or diversity in South Africa. Whole genome sequences of 387 S . Infantis isolates from South Africa (2004-2020) were analysed for genetic phylogeny, recombination frequency, antimicrobial resistance (AMR) determinants, plasmid presence and overall gene content. The population structure of South African S . Infantis was substantially different to S . Infantis reported elsewhere; only two thirds of isolates belonged to eBG31, while the remainder were identified as eBG297, a much rarer group globally. Significantly higher levels of recombination were observed in the eBG297 isolates, which was associated with the presence of prophages. The majority of isolates were putatively susceptible to antimicrobials (335/387) and lacked any plasmids (311/387); the megaplasmid pESI was present in just one isolate. A larger proportion of eBG31 isolates, 19% (49/263), contained at least one AMR determinant, compared to eBG297 at 2% (3/124). Comparison of the pan-genomes of isolates from either eBG identified 943 genes significantly associated with eBG, with 43 found exclusively in eBG31 isolates and 34 in eBG297 isolates. This, along with the single nucleotide polymorphism distance and difference in resistance profiles, suggests that eBG31 and eBG297 isolates occupy different niches within South Africa. If antibiotic-resistant S . Infantis emerges in South Africa, probably through the spread of the pESI plasmid, treatment of this infection would be compromised., Competing Interests: The authors declare that there are no conflicts of interest., (© 2022 The Authors.)

The study of non-typhoid Salmonella in broiler integrations has been limited by the resolution of typing techniques. Although serotyping of Salmonella isolates is used as a traditional approach, it is not of enough resolution to clearly understand the dynamics of this pathogen within poultry companies. The aim of this research was to investigate the epidemiology and population dynamics of Salmonella serotypes in 2 poultry integrations using a whole genome sequencing approach. Two hundred and forty-three Salmonella isolates recovered from the broiler production chain of 2 integrated poultry companies were whole genome sequenced and analyzed with dedicated databases and bioinformatic software. The analyses of sequences revealed that S. Infantis was the most frequent serotype (82.3%). Most isolates showed a potential for resistance against medically important antibiotics and disinfectants. Furthermore, 97.5% of isolates harbored the pESI-like mega plasmid, that plays an important role in the global dissemination of AMR. SNP tree analysis showed that there were clones that are niche-specific while other ones were distributed throughout the broiler production chains. In this study, we demonstrated the potential of whole genome sequencing analysis for a comprehensive understanding of Salmonella distribution in integrated poultry companies. Data obtained with these techniques allow determination of the presence of genetic factors that play an important role in the environmental fitness and pathogenicity of Salmonella. [ABSTRACT FROM AUTHOR]

Salmonella Infantis has been the etiological agent of numerous foodborne outbreaks of nontyphoidal Salmonella. Consequently, there is an emergent need to mitigate Salmonella Infantis among poultry. Thus, this study evaluated the efficacy of cetylpyridinium chloride (CPC) versus peroxyacetic acid (PAA), on bone-in, skin-on chicken thighs for the reduction of Salmonella and changes in the microbiota. Exactly 100 skin-on, bone-in chicken thighs (2 trials, 0 and 24 h, k = 5, n = 5, N = 50) were inoculated with 108 CFU/mL of a nalidixic acid resistant strain of S. Infantis for an attachment of 106 CFU/g. Thighs were treated with 20 s part dips (350 mL): a no inoculum, no treatment control (NINTC); no treatment control (NTC); tap water (TW); TW+CPC; TW+PAA. Following treatment, thighs were rinsed in 150 mL of nBPW, and rinsates were collected. Rinsates were spot plated for Salmonella and aerobic bacteria (APC). Log 10 transformed counts were analyzed using a mixed-effects model (random effect = trial) with means separated using Tukey's HSD (P ≤ 0.05). The genomic DNA of rinsates was extracted, and the 16S rDNA was sequenced on an Illumina MiSeq. Microbiota data were analyzed using QIIME2, with data considered significant at P ≤ 0.05 (main effects) and Q≤0.05 (pairwise differences). Treatment × time interactions were observed for both Salmonella and APC (P < 0.05). The treatment of thighs with PAA and CPC reduced Salmonella and APC in respect to the controls. Numerically, thighs treated with CPC had less Salmonella (4.29 log 10 CFU/g) and less APC (4.56 log 10 CFU/g) at 24 h than all other treatments (P > 0.05). Differences in diversity metrics were not consistently observed between treatments; however, in trial 2, the NTC treated thighs were different than those treated with CPC (P < 0.05; Q < 0.05). In both trials, ANCOM, the analysis of microbiome compositional profiles, revealed shifts at both the phylum and order levels with thighs being different in the relative abundances of Proteobacteria (P < 0.05). In conclusion, treatment of skin-on poultry parts with CPC may reduce the risk of foodborne outbreaks caused by Salmonella Infantis. [ABSTRACT FROM AUTHOR]

Salmonella enterica is an important foodborne pathogen. Commercial poultry are the main reservoirs of Salmonella enterica, leading to the contamination of food and outbreaks in humans. The vaccination of chickens is one of the most important strategies to reduce the number of Salmonella in poultry farms. Unfortunately, commercial vaccines have not been fully effective in controlling the spread and do not contain all the Salmonella serovars that circulate on farms. In this study, we evaluate a new, cochleate-based, trivalent injectable vaccine against S. Enteritidis, S. Typhimurium and S. Infantis, describing the vaccine security, capacity to induce specific anti-Salmonella serovar IgY and the gene expression of immune markers related to CD4 and CD8 T-cell-mediated immunity. Efficacy was evaluated through oral challenges performed separately for each Salmonella serotype. The efficacy and safety of the trivalent vaccine was proven under controlled conditions. The vaccine has no local or systemic reactions or adverse effects on poultry performance related to the vaccine. The vaccine provided significantly increased serum IgY titer levels, significantly reduced Salmonella CFU/g present in the cecum and an increased CD4+/CD8+ ratio in vaccinated animals when challenged with S. Infantis, S. Enteritidis and S. Typhimurium. These results indicate that this new trivalent vaccine does not generate adverse effects in poultry and produces an increase in neutralizing antibodies against the three Salmonella serovars. [ABSTRACT FROM AUTHOR]

Human salmonellosis incidence is increasing in the European Union (EU). Salmonellaenterica subsp. enterica serovar Enteriditis, Salmonellaenterica subsp. enterica serovar Typhimurium (including its monophasic variant) and Salmonellaenterica subsp. enterica serovar Infantis represent targets in control programs due to their frequent association with human cases. This study aimed to detect the most prevalent serotypes circulating in Abruzzo and Molise Regions between 2015 and 2020 in the framework of the Italian National Control Program for Salmonellosis in Poultry (PNCS)]. A total of 332 flocks of Abruzzo and Molise Regions were sampled by veterinary services in the period considered, and 2791 samples were taken. Samples were represented by faeces and dust from different categories of poultry flocks: laying hens (n = 284), broilers (n = 998), breeding chickens (n = 1353) and breeding or fattening turkeys (n = 156). Breeding and fattening turkeys had the highest rate of samples positive for Salmonella spp. (52.6%; C.I. 44.8%–60.3%). Faeces recovered through boot socks represented the greatest number of positive samples (18.2%). Salmonellaenterica subsp. enterica serovar Infantis was the prevalent serotype in breeding and fattening turkeys (32.7%; C.I. 25.8%–40.4%) and in broiler flocks (16.5%; C.I. 14.4%–19.0%). Salmonellaenterica subsp. enterica serovar Typhimurium was detected at low levels in laying hens (0.7%; C.I. 0.2%–2.5%) followed by breeding and fattening turkeys (0.6%; C.I. 0.2%–2.5%). Salmonellaenterica subsp. enterica serovar Enteriditis was also detected at low levels in laying hens (2.5%; C.I. 1.2%–5.0%). These findings highlight the role of broilers and breeding/fattening turkeys as reservoirs of Salmonella spp. and, as a consequence, in the diffusion of dangerous serotypes as Salmonellaenterica subsp. enterica serovar Infantis. This information could help veterinary services to analyze local trends and to take decisions not only based on indications from national control programs, but also based on real situations at farms in their own competence areas. [ABSTRACT FROM AUTHOR]

Non-typhoidal Salmonella infections remain a significant public health problem worldwide. In this study, we present the first detailed genomic analysis report based on short-read (Illumina) whole-genome sequencing (WGS) of 45 multidrug-resistant (MDR) Salmonella enterica subsp. enterica serotype Infantis isolates from poultry and meat product samples obtained in Russia during 2018–2020, and long-read (MinION) WGS of five more representative isolates. We sought to determine whether foodborne S. Infantis have acquired new characteristics, traits, and dynamics in MDR growth in recent years. All sequenced isolates belonged to the sequence type ST32 and more than the half of isolates was characterized by six similar antimicrobial susceptibility profiles, most of which corresponded well with the antimicrobial resistance determinants to aminoglycosides, sulphonamides, tetracycline, and chloramphenicol revealed in silico. Some of the isolates were characterized by the presence of several types of plasmids simultaneously. Plasmid typing using WGS revealed Col440I, ColpVC, ColRNAI, IncFIB, IncFII, IncX1, IncHI2, IncHI2A, and IncN replicons. The identified virulence genes for 45 whole genomes of S. Infantis were similar and included 129 genes encoding structural components of the cell, factors responsible for successful invasion of the host, and secreted products. These data will be a valuable contribution to further comparative genomics of S. Infantis circulating in Russia, as well as to epidemiological surveillance of foodborne Salmonella isolates and investigations of Salmonella outbreaks. [ABSTRACT FROM AUTHOR]

Background: Multidrug-resistant Salmonella strains are frequently encountered problems worldwide with considerable increased occurrences in recent years. The aim of this study was to investigate the occurrence and frequency of antimicrobial resistance and associated resistance genes in Salmonella isolates from broiler farms in different regions of Iran covering a time period of four years. Results: From 2007 to 2011, 36 Salmonella strains were isolated from broiler farms located in three northern provinces of Iran. The isolates were serotyped, antimicrobial susceptibility tested, and characterized for antimicrobial resistance genes associated to the phenotype. Pulsed-field gel electrophoresis (PFGE) was applied for comparison of genetic relatedness. Two serovars were detected among the isolates; Salmonella enterica serovar Infantis (75%) and S. Enteritidis (25%). Thirty-four (94%) of the isolates exhibited resistance to nalidixic acid and ciprofloxacin caused by a single mutation in the quinolone resistance-determining region (QRDR) of gyrA. For all strains this mutation occurred in the codon of Asp87 leading to a Asp87- Tyr, Asp87- Gly or Asp Asn substitutions. All S. Infantis (n = 27) were resistant to tetracycline, spectinomycin, streptomycin, and sulfamethoxazole and harbored the associated resistance genes; tetA, dfrA14, aadA1, and sulI together with class 1 integrons. The isolates revealed highly similar PFGE patterns indicating clonal relatedness across different geographical locations. Conclusion: The data provided fundamental information applicable when launching future control programs for broilers in Iran with the aim to conserve the effectiveness of important antimicrobials for treatment in humans. [ABSTRACT FROM AUTHOR]

The article discusses a study which characterized Salmonella enterica serovar Infantis (S. Infantis) isolates carrying cefotaxime (CTX)-M-14 extended-spectrum β-lactamase (ESBL) derived from broiler chickens raised at a poultry processing plant in western Japan in January 2010. It concludes that the spread of cephalosporin-resistant Salmonella spp. in poultry via the transmissible resistance plasmids elicits serious veterinary and public health concerns.

Abstract: The aim of the study was to investigate the potential spread of the previously described multidrug-resistant (MDR) Hungarian clone of Salmonella Infantis of broiler origin in Europe. Therefore, 76 strains isolated between 2004 and 2009 from raw meat and fecal samples of broiler origin in nine European countries – including Hungary – were examined by phage typing, antimicrobial resistance typing, pulsed-field gel electrophoresis (PFGE) profile and plasmid analysis. The strains could be divided into two large PFGE clusters with 92% similarity. Cluster A (n=39) contained 15 German, seven Italian, five British, five Polish isolates, one Austrian and one Hungarian isolate. Five Hungarian isolates that were isolated prior to the appearance of the MDR clone also belonged to this cluster. Strains of this cluster comprised seven pulsotypes and 14 different phage types and were mostly susceptible to the 12 antimicrobials tested. Cluster B (n=33) contained all but one of the recent Austrian (n=14) and of Hungarian (n=9), six Polish, one Italian and one German as well as the single Turkish and the Romanian strains, representing five pulsotypes. The strains of this cluster were mostly PT213, with MDR (nalidixic acid-streptomycin-sulphomamide-tetracycline), and the carriage of the same class 1 integron located on a large plasmid (>168kb) characteristic of the current predominant Hungarian clone. The results suggest that two large related clusters (A and B) of S. Infantis isolates can be found in various European countries, of which Austrian and Polish MDR clones of cluster B are identical with, or closely related to, the dominant Hungarian clone. The emergence of a few dominant MDR S. Infantis clones in broilers reported here, raises the possibility that further dissemination of such clones in broilers and in broiler meat may occur and represent a potential threat to public health in Europe. [Copyright &y& Elsevier]

Abstract: During 2005–2006, Salmonella enterica serotype Infantis strains isolated from human and non-human sources and resistant to ampicillin (A), chloramphenicol (C), streptomycin (S), sulphonamide (Su), tetracycline (T), kanamycin (K) and trimethoprim/sulfamethoxazole (Sxt) emerged in Italy. The aim of this study was to analyse the molecular basis of antibiotic resistance and to evaluate the clonal origin of multiresistant S. Infantis strains isolated from different sources. Seventy S. Infantis strains, susceptible or resistant to antimicrobial drugs, were chosen for this study. Polymerase chain reaction (PCR) and conjugation experiments were performed to identify and localise the resistance genes in multidrug-resistant strains. PCR-based replicon typing was carried out for characterisation of conjugative plasmids. All strains were tested by pulsed-field gel electrophoresis (PFGE) according to the PulseNet protocol, and cluster analysis was performed using BioNumerics software. Strains with resistance (R)-type ACSSuTKSxt harboured bla TEM-1, strA-B, sul2, tet(B), catA1 and aphA-1 resistance genes as well as a 2.2-kb class 1 integron containing folA, catB3, aadA4 and sul1 gene cassettes. A unique plasmid, belonging to the HI1 incompatibility group, harboured all the resistance genes. Cluster analysis showed that all ACSSuTKSxt-resistant strains belonged to a large cluster (A) with >90% genetic similarity. The presence of a plasmid harbouring all the resistance gene cassettes as well as molecular typing by PFGE demonstrated the circulation of a cluster of S. Infantis R-type ACSSuTKSxt during 2005–2006 in Italy. The presence of a plasmid conferring multidrug resistance could have facilitated the spread of a group of similar isolates through a variety of sources. [Copyright &y& Elsevier]

The article examines the molecular characteristics of antibiotic resistance and the emergence of beta-lactamase-producing Salmonella infantis from pigs. Materials and methods used in this study are detailed. The isolation and identification of Salmonella serotypes are described. Commonly observed resistance phenotypes were against streptomycin, oxytetracycline, sulfamethoxazole, ampicilin, chloramphenicol, cephalothin, cefoxitin, ceftazidime and kanamycin. Genetic fingerprinting analysis and pulsed-field gel electrophoresis confirmed the isolates to be Salmonella Typhimurium.

Abstract: An epidemiologic study was conducted to investigate the incidence and characterize the antimicrobial resistance determinants, analyzing plasmid profiles, and establishing the genetic relationship among β-lactam-resistant isolates of Salmonella Infantis from broilers in Southern Japan. A total of 120 isolates were recovered from 56 flocks belonging to 44 holdings during 2004–2006. The percentages of resistance were as follows: ampicillin (24%), cephalothin (23%), cefoxitin (0%), ceftazidime (11%), cefotaxime (11%), chloramphenicol (0%), kanamycin (7.5%), ofloxacin (20%), oxytetracycline, streptomycin and sulfamethoxazole (100%) and trimethoprim (75%). The incidence of bla TEM-encoded β-lactam resistance in 2004–2006 was significantly higher than in 1998–2003 (P <0.001). BlnI-digested PFGE patterns generated two related clusters implicated in the dissemination of β-lactam resistance. Two types of plasmid profiles were observed and two plasmids of ca. 50 and 180-kb size were carried by β-lactam-resistant isolates. Streptomycin resistance was conferred by aadA1 (n =116), aadA1-aadA2 (n =1), and aadA1-strA-strB (n =3). Resistances to kanamycin, oxytetracycline, sulfamethoxazole and trimethoprim were conferred by aphA1 (n =9, 100%), tetA (n =120, 100%) sul1 (n =120, 100%) and dfrA5 (n =90, 100%), respectively. Two types of class 1 integrons were detected: 1.0kb (n =120) and, 1.0/1.5kb (n =3). Integrons of 1.0/1.5kb were found in isolates with the aadA1-strA-strB gene combination. For the first time, all S. Infantis isolates showed resistance to at least three classes of antimicrobial agents; and the intestinal tract of healthy poultry was a reservoir of the extended-spectrum cephalosporin-resistant isolates of serovar Infantis. [Copyright &y& Elsevier]

The article deals with a study that examined the safety and efficacy of a novel trivalent inactivated Salmonella vaccine in chickens. A Salmonella Enteritidis (SE) strain was used as a vaccine strain in this study. Enzyme-linked immunosorbent assay (ELISA) was used to measure serum immunoglobulin G antibody titers against H-antigens of SE, Salmonella Typhimurium (ST) and Salmonella Infantis (SI). Results of the study showed that there has been a significant reduction in the shedding of SE into the cecal droppings in vaccinated chickens compared to those of unvaccinated ones. The study also found a significant reduction in Salmonella Heidelberg (SH) recovered from the spleens.

Abstract: Salmonella is a well-documented pathogen known to occur in a wide range of foods, especially poultry products. The most frequently reported food-sources of human infection are eggs and egg products. In this study, in order to describe Salmonella contamination of egg products, 144 liquid egg samples were collected from 3 different egg-breaking plants during the 3 sampling periods. Salmonella detection was performed on raw samples stored at 2 °C for 2 days (D +2) and on pasteurised samples stored at 2 °C at D +2 and at shelf-life date. Salmonella was detected in 130 of the 144 raw egg samples collected and in 11 of the 288 pasteurised egg samples analysed. 740 Salmonella isolates were collected and serotyped: 14 serovars were demonstrated. A great diversity, particularly during summer, was noted. The dominant serovars were S. Enteritidis, S. Typhimurium and S. Infantis, mainly found in whole raw egg products. Typing of 325 isolates of S. Enteritidis, 54 isolates of S. Typhimurium and 58 isolates of S. Infantis was carried out by macrorestriction of the genomic DNA with XbaI and SpeI enzymes followed by pulsed field gel electrophoresis (PFGE). The Salmonella Enteritidis isolates could be grouped into 3 clusters. Cluster 1 was predominant at all 3 egg-breaking companies during the different sampling periods. This cluster seemed to be adapted to the egg-breaking plants. Cluster 2 was linked to plant 1 and cluster 3 to plant 3. Two main clusters of Salmonella Typhimurium were demonstrated. Cluster A was mainly found at plant 2 during autumn. Plant 3 was contaminated by all the Salmonella Typhimurium genotypes but in a more sporadic manner during the three seasons studied. Plant 1 seemed to be less contaminated by Salmonella Typhimurium than the others. Three clusters and 2 genotypes of Salmonella Infantis were shown. The main cluster, cluster α, consisted of 75% of the S. Infantis isolates and was mainly found during summer at plants 1 and 3. Plant 2 seemed to be less contaminated by S. Infantis. In this study, molecular typing demonstrated that, although certain clusters were common to all three companies, specific clusters, notably of S. Enteritidis were present at each plant. [Copyright &y& Elsevier]

Salmonella comprises over 2500 serotypes and foodborne contamination associated with this pathogen remains an important health concern worldwide. During the last decade, a shift in serotype prevalence has occurred as traditionally less prevalent serotypes are increasing in frequency of infections, especially those related to poultry meat contamination. S. Infantis is one of the major emerging serotypes, and these strains commonly display antimicrobial resistance and can persist despite cleaning protocols. Thus, this work aimed to isolate S. Infantis strains from a poultry meat farm in Santiago, Chile and to characterize genetic variations present in them. We determined their genomic and phenotypic profiles at different points along the production line. The results indicate that the strains encompass 853 polymorphic sites (core-SNPs) with isolates differing from one another by 0–347 core SNPs, suggesting variation among them; however, we found discrete correlations with the source of the sample in the production line. Furthermore, the pan-genome was composed of 4854 total gene clusters of which 2618 (53.9%) corresponds to the core-genome and only 181 (3.7%) are unique genes (those present in one particular strain). This preliminary analysis will enrich the surveillance of Salmonella, yet further studies are required to assess their evolution and phylogeny. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop and characterize Salmonellaenterica serovar Infantis (S. Infantis) cochleates protected by encapsulation technology as a potential vaccine and to determine its safety in pullets. Cochleates were encapsulated by two technologies, spray drying and ionotropic gelation at different concentrations (0–15% v/v), and were characterized by physicochemical properties, protein content and Fourier Transform Infrared Spectroscopy (FTIR). The cochleates were white liquid suspensions with tubular shapes and a protein content of 1.0–2.1 mg/mL. After encapsulation by spray drying, microparticles ranged in size from 10.4–16.9 µm, were spherical in shape, and the protein content was 0.7–1.8 mg/g. After encapsulation by ionotropic gelation, beads ranged in size from 1620–1950 µm and were spherical in shape with a protein content of 1.0–2.5 mg/g. FTIR analysis indicated that both encapsulation processes were efficient. The cochleates encapsulated by ionotropic gelation were then tested for safety in pullets. No ill effect on the health of animals was observed upon physical or postmortem examination. In conclusion, this study was the first step in developing a potential oral S. Infantis vaccine safe for poultry using a novel cochleate encapsulation technology. Future studies are needed to determine the effectiveness of the vaccine. [ABSTRACT FROM AUTHOR]

Abstract: During the 10-month study period Salmonella contamination of broiler houses and the flocks reared in three farms (A, B and C), the slaughter houses where the flocks were slaughtered, as well as the carcass and retail raw meat products originating from them was investigated. In the broiler farm A five consecutive flocks, in the B and C farms one flock was sampled. Environmental samples were taken prior to the introductions. Environmental, drinking water, feed and faecal samples were collected regularly using standard methods. Before and during processing of the flocks, environmental and carcass samples were taken at the abattoirs. Salmonella contamination of the carcass, retail meat, as well as stool samples of farm and abattoir workers and from human illnesses registered in the same period and region were also examined. Isolation, sero-, phage- and antibiotic resistance typing, class 1 integron and plasmid profiling of the strains were performed; their genetic relationship was assessed by PFGE. Although the broiler house and the faecal samples of the 5 flocks of the farm A were negative for Salmonella, S. infantis was isolated from 20–100% of the abattoir carcass samples. The retail raw meat samples were 0–100% S. infantis positive. The environmental samples of farm B were Salmonella negative, but the examined flock was contaminated: S. infantis was identified from 43% of the faecal samples. This serotype was identified in 100% of the carcass and retail raw meat samples. From environmental samples taken before the arrival of the 1-day-old chicks in the broiler house C, S. infantis was cultured. S. infantis prevalence in the faecal samples was 35% and all the carcass and retail raw meat samples were S. infantis contaminated. Altogether 164 S. infantis strains were isolated out of which 145 were further characterized. The vast majority (142/145) of the strains belonged to phage types 217 and 213. All but one were characterized by the nalidixic acid-streptomycin-sulphonamide-tetracycline resistances, had an 885 bp class 1 integron and a large plasmid of >168 kb in size. The strains showed ≥88.7% genetic similarity. The results obtained shows that the same multi-drug resistant S. infantis clone was spread from the examined broiler farms contaminating the slaughter and the retail meat and appeared in the human illnesses of the examined region that was earlier detected as the dominant clone characteristic of the broiler and human population of the whole country. [Copyright &y& Elsevier]

Aims: We developed, optimized and tested two novel PCR assays specific for Salmonella enterica subspecies enterica serovar Infantis. Methods and Results: The fljB gene was chosen as the target sequence. Primers were designed on a consensus sequence built by sequencing the fljB gene of five genetically unrelated Hungarian S. Infantis strains and using sequence data from the GenBank ( ). Two alternative assays were designed, which share the reverse primer. Both proved to be highly specific to S. Infantis, neither reacted with 42 other nontyphoidal serovariants tested. The detection limit of the assays was determined to be 105 CFU ml−1 from pure culture, and 106 CFU g−1 from artificially spiked chicken faeces samples. Conclusions: Although the detection limit is rather high to allow for using them for direct detection, the assays may be useful in identification of S. Infantis both for diagnostic and for research purposes. Significance and Impact of the Study: The described PCR assays allow for the correct identification of S. Infantis even when traditional serotyping methods fail because lack of expression of flagellar antigens. [ABSTRACT FROM AUTHOR]

Aims: To compare Salmonella enterica serotype Infantis isolates obtained from patients or the environment of a veterinary teaching hospital over a period of 9 years following a nosocomial outbreak to determine whether isolates were epidemiologically related or represented unrelated introductions into the hospital environment. Methods and Results: Fifty-six S. Infantis isolates were compared based on their phenotypic (antimicrobial drug [AMD] susceptibility pattern) and genotypic (pulsed-field gel electrophoresis [PFGE] pattern and presence of integrons) characteristics. Epidemiologically unrelated S. Infantis isolates clustered separately from all but two of the hospital isolates, and several isolates from different years and various sources were indistinguishable from each other in cluster analysis of two-enzyme PFGE results. A high percentage of isolates (80·3%) were resistant to at least one AMD, with 67·8% showing resistance to >5 AMD. The majority (74·1%) of isolates tested contained type 1 integrons. Conclusion: Results strongly suggest that there was nosocomial transmission of S. Infantis during the initial outbreak, and that contamination arising from this outbreak persisted across years despite rigorous hygiene and biosecurity precautions and may have led to subsequent nosocomial infections. Significance and Impact of the Study: Evidence of persistence and transmission of Salmonella clones across years, even in the face of rigorous preventive measures, has important implications for other facilities that have experienced outbreaks of Salmonella infections. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate bacterial load in ready-to-sale sheep meat with special reference to Salmonella. Samples were collected from 100 sheep carcasses from retail meat shops in domestic markets. On carcasses, where bacterial counts were obtained, the mean of the log10 aerobic plate count was 7.26 cfu g−1, and that of total coliform count and total Escherichia coli count was 4.11 log10 cfu g−1 and 3.03 log10 cfu g−1, respectively. All the samples (100) were found positive for coliforms, 49.0% were positive for E. coli and 3.0% were positive for Salmonella. The isolates were serotyped as Salmonella infantis having antigenic structure 6, 7: r: 1, 5. Antibiogram revealed highest (100.0%) sensitivity towards amikacin, ceftriaxone, ciprofloxacin, chloramphenicol, colistin sulphate, gentamicin and nalidixic acid followed by cefuroxime and tetracycline (66.67% each) and cotrimoxazole (33.33%). All the strains were resistant to ampicillin. [ABSTRACT FROM AUTHOR]

Chilled breasts of chicken were inoculated with Salmonella infantis or Pseudomonas aeruginosa and then given one of the following treatments: (i) exposure to gaseous ozone (>2000 ppm for up to 30 min); (ii) storage under 70% CO2:30% N2; and (iii) exposure to gaseous ozone (>2000 ppm for 15 min) followed by storage under 70% CO2:30% N2; all storage at 7 °C. Gaseous ozone reduced the counts of salmonellae by 97% and pseudomonads by 95%, but indigenous coliforms were unaffected. Under the modified atmosphere, the cell count of S. infantis was reduced by 72% following initial exposure and then stabilised, coliforms grew, but Ps. aeruginosa behaved like S. infantis––initial reduction (58%) followed by stability. Exposure to gaseous ozone followed by gas packaging allowed survival of S. infantis, Ps. aeruginosa and coliforms over 9 days at 7 °C, but there was no evidence of any sensory deterioration. It is proposed that the latter treatment could, in a modified form perhaps, be used to reduce the contamination of chicken carcasses with salmonellae and improve their shelf-life. [Copyright &y& Elsevier]

Dairy cows can be reservoirs of foodborne pathogens such as Salmonella that pose serious public health risks to humans. The study was designed to examine the molecular epidemiology and antimicrobial resistance profiles of Salmonella isolates from dairy heifer calves and adult lactating cows in the pasture-based system of Australia. A total of 838 animals (328 heifer calves and 510 lactating cows) from 22 farms were sampled. Overall, 54 Salmonella isolates were recovered (calves 28/328 and cows 26/510). A herd-level Salmonella prevalence of 50% (95% confidence interval: 31%-69%) was recorded. Within-herd prevalence for Salmonella ranged between 4%-29% and 4%-45% among the heifer calves and adult lactating cows, respectively. Three different serovars were identified with Salmonella Infantis being the most common serovar (n = 33, 61%) followed by Salmonella Kiambu (n = 20, 37.0%) and one isolate of Salmonella Cerro (2%). The highest antimicrobial resistance prevalence of Salmonella isolates was found against streptomycin (n = 31, 57%), followed by cefoxitin (n = 12, 22%), ceftriaxone (n = 2, 4%), and chloramphenicol (n = 1, 2%). Multiple class resistance was observed on 4 isolates against cefoxitin, chloramphenicol, and streptomycin. Multilocus sequence types ST32 (61%), ST309 (37%), and ST367 (2%) were strongly linked to the serovars Salmonella Infantis, Salmonella Kiambu, and Salmonella Cerro, respectively. Whole genome sequencing of Salmonella isolates detected only 2 resistance genes: aac(6') gene that confers resistance against aminoglycosides among 40.7% of the isolates, and a single isolate positive for the blaDHA-16 gene. Two distinct clusters among the serovars were observed suggesting 2 independent sources of spread. Despite the low prevalence of antimicrobial resistance among Salmonella from the dairy farms, our findings contribute to the regional and national understanding of antimicrobial resistance in dairy herds in Australia. There is need for continued antimicrobial resistance stewardship and surveillance programs to ensure the production of high-quality food products and the long-term protection of both animal and human health., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Non-typhoidal Salmonella infections remain a significant public health problem worldwide. In this study, we present the first detailed genomic analysis report based on short-read (Illumina) whole-genome sequencing (WGS) of 45 multidrug-resistant (MDR) Salmonella enterica subsp. enterica serotype Infantis isolates from poultry and meat product samples obtained in Russia during 2018-2020, and long-read (MinION) WGS of five more representative isolates. We sought to determine whether foodborne S. Infantis have acquired new characteristics, traits, and dynamics in MDR growth in recent years. All sequenced isolates belonged to the sequence type ST32 and more than the half of isolates was characterized by six similar antimicrobial susceptibility profiles, most of which corresponded well with the antimicrobial resistance determinants to aminoglycosides, sulphonamides, tetracycline, and chloramphenicol revealed in silico. Some of the isolates were characterized by the presence of several types of plasmids simultaneously. Plasmid typing using WGS revealed Col440I, ColpVC, ColRNAI, IncFIB, IncFII, IncX1, IncHI2, IncHI2A, and IncN replicons. The identified virulence genes for 45 whole genomes of S. Infantis were similar and included 129 genes encoding structural components of the cell, factors responsible for successful invasion of the host, and secreted products. These data will be a valuable contribution to further comparative genomics of S. Infantis circulating in Russia, as well as to epidemiological surveillance of foodborne Salmonella isolates and investigations of Salmonella outbreaks.