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Salmonella enterica variants exhibit diverse host adaptation, outcome of infection, and associated risk to food safety. Analysis of the distribution of Salmonella enterica serovar Derby (S. Derby) subtypes in human and swine identified isolates with a distinct PFGE profile that were significantly under-represented in human infections, consistent with further host adaptation to swine. Here we show that isolates with this PFGE profile form a distinct phylogenetic sub-clade within S. Derby and exhibit a profound reduction in invasion of human epithelial cells, and a relatively small reduction in swine epithelial cells. A single missense mutation in hilD, that encodes the master-regulator of the Salmonella Pathogenicity Island 1 (SPI-1), was present in the adapted lineage. The missense mutation resulted in a loss of function of HilD that accounted for reduced invasion in human epithelial cells. The relatively small impact of the mutation on interaction with swine cells was consistent with an alternative mechanism of invasion in this pathogen-host combination.

West Nile (WNV) and Usutu (USUV) viruses are mosquito-borne flaviviruses. Thanks to their importance as zoonotic diseases, a regional plan for surveillance of Arboviruses was implemented in Emilia-Romagna in 2009. The province of Ferrara belongs to the Emilia-Romagna region, and it is an endemic territory for these viruses, with favorable ecological conditions for abundance of mosquitoes and wild birds. From 2015 to 2019, we collected 1842 dead-found birds at a wildlife rehabilitation center, which were analysed by three different PCRs for the detection of WNV and USUV genomes. August was characterized by the highest infection rate for both viruses. Columbiformes scored the highest USUV prevalence (8%), while Galliformes and Strigiformes reported the highest prevalence for WNV (13%). Among Passeriformes (the most populated Order), Turdus merula was the most abundant species and scored the highest prevalence for both viruses. To optimize passive surveillance plans, monitoring should be focused on the summer and towards the avian species more prone to infection by both viruses.

We retrospectively analyzed a rare Salmonella enterica serovar Manhattan outbreak that occurred in Italy in 2009 to evaluate the potential of new genomic tools based on differential single nucleotide polymorphism (SNP) analysis in comparison with the gold standard genotyping method, pulsed-field gel electrophoresis. A total of 39 isolates were analyzed from patients ( n = 15) and food, feed, animal, and environmental sources ( n = 24), resulting in five different pulsed-field gel electrophoresis (PFGE) profiles. Isolates epidemiologically related to the outbreak clustered within the same pulsotype, SXB_BS.0003, without any further differentiation. Thirty-three isolates were considered for genomic analysis based on different sets of SNPs, core, synonymous, nonsynonymous, as well as SNPs in different codon positions, by Bayesian and maximum likelihood algorithms. Trees generated from core and nonsynonymous SNPs, as well as SNPs at the second and first plus second codon positions detailed four distinct groups of isolates within the outbreak pulsotype, discriminating outbreak-related isolates of human and food origins. Conversely, the trees derived from synonymous and third-codon-position SNPs clustered food and human isolates together, indicating that all outbreak-related isolates constituted a single clone, which was in line with the epidemiological evidence. Further experiments are in place to extend this approach within our regional enteropathogen surveillance system.

Current antibiotics for treating Clostridium difficile infections (CDI), that is, metronidazole, vancomycin and more recently fidaxomicin, are mostly effective but treatment failure and disease relapse remain as significant clinical problems. The shortcomings of these agents are attributed to their low selectivity for C. difficile over normal gut microflora and their ineffectiveness against C. difficile spores. This Letter reports that certain diarylacylhydrazones identified during a high-throughput screening/counter-screening campaign show selective activity against two Clostridium species (C. difficile and Clostridium perfringens) over common gut commensals. Representative examples are shown to possess activity similar to vancomycin against clinical C. difficile strains and to kill stationary-phase C. difficile cells, which are responsible for spore production. Structure-activity relationships with additional synthesised analogues suggested a protonophoric mechanism may play a role in the observed activity/selectivity and this was supported by the well-known protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) showing selective anti-Clostridium effects and activity similar to diarylacylhydrazones against stationary-phase C. difficile cells. Two diarylacylhydrazones were shown to be non-toxic towards human FaDu and Hep G2 cells indicating that further studies with the class are warranted towards new drugs for CDI.

The first case of plasmid-mediated resistance to colistin due to the mcr-1 gene was reported in China in late 2015 ([1][1]). Soon after, the same gene was detected by a number of retrospective analyses ([2][2]). Resistance to colistin is generally believed to be related to its use in animal

We report the draft genome sequence of Salmonella enterica subsp. enterica serovar Napoli strain SN310, isolated from a stool sample of an affected pupil during a multischool outbreak in 2014 in Milan, Italy. This represents the first reported draft genome sequence of the emerging serovar Napoli.

In bacteria, multidrug-resistance pumps (MDRs) confer resistance to chemically unrelated amphipathic toxins. A major challenge in developing efficacious antibiotics is identifying antimicrobial compounds that are not rapidly pumped out of bacterial cells. The plant antimicrobial berberine, the active component of the medicinal plants echinacea and golden seal, is a cation that is readily extruded by bacterial MDRs, thereby rendering it relatively ineffective as a therapeutic agent. However, inhibition of MDR efflux causes a substantial increase in berberine antimicrobial activity, suggesting that berberine and potentially many other compounds could be more efficacious if an effective MDR pump inhibitor could be identified. Here we show that covalently linking berberine to INF 55 , an inhibitor of Major Facilitator MDRs, results in a highly effective antimicrobial that readily accumulates in bacteria. The hybrid molecule showed good efficacy in a Caenorhabditis elegans model of enterococcal infection, curing worms of the pathogen.

The alarming increase of antibiotic-resistant bacterial pathogens points to the need for novel therapeutic approaches to combat infection. To discover novel antimicrobials, we devised a screen to identify compounds that promoted the survival of the model laboratory nematode Caenorhabditis elegans infected with the human opportunistic pathogen Enterococcus faecalis . E. faecalis colonizes the nematode intestinal tract, forming a persistent lethal infection. Infected nematodes were rescued by antibiotic treatment in a dose-dependent manner, and antibiotic treatment markedly reduced the number of bacteria colonizing the nematode intestine. To facilitate high throughput screening of compound libraries, we adapted a previously developed agar-based C. elegans - E. faecalis infection assay so that it could be carried out in liquid medium in standard 96-well microtiter plates. We used this simple infection system to screen 6,000 synthetic compounds and 1,136 natural product extracts. We identified 16 compounds and 9 extracts that promoted nematode survival. Some of the compounds and extracts inhibited E. faecalis growth in vitro , but, in contrast to traditional antibiotics, the in vivo effective dose of many of these compounds was significantly lower than the minimum inhibitory concentration needed to prevent the growth of E. faecalis in vitro . Moreover, many of the compounds and extracts had little or no affect on in vitro bacterial growth. Our findings indicate that the whole-animal C. elegans screen identifies not only traditional antibiotics, but also compounds that target bacterial virulence or stimulate host defense.

Fumonisins are mycotoxins found primarily in corn and corn products that are produced by Fusarium verticillioides, F. proliferatum, and several other Fusarium species. The toxicity of fumonisin B₁ (FB) from culture material with and without activated carbon was evaluated using weanling piglets. Fifty-six weanling pigs were assigned to one of four treatments diets based on BW. The treatment diets were 1) control = corn-soybean basal diet with

We announce the draft genome sequence of Salmonella enterica subsp. enterica serovar Manhattan strain 111113, isolated from a patient during an outbreak in northern Italy. The genome, which was obtained with Illumina MiSeq technology, is composed of 21 contigs for a total of 4,684,342 bp, with a G+C content of 52.17%.

The nematode Caenorhabditis elegans is a unique whole animal model system for identifying small molecules with in vivo anti-infective properties. C. elegans can be infected with a broad range of human pathogens, including Enterococcus faecalis, an important human nosocomial pathogen with a mortality rate of up to 37% that is increasingly acquiring resistance to antibiotics. Here, we describe an automated, high throughput screen of 37,200 compounds and natural product extracts for those that enhance survival of C. elegans infected with E. faecalis. The screen uses a robot to accurately dispense live, infected animals into 384-well plates, and automated microscopy and image analysis to generate quantitative, high content data. We identified 28 compounds and extracts that were not previously reported to have antimicrobial properties, including 6 structural classes that cure infected C. elegans animals but do not affect the growth of the pathogen in vitro, thus acting by a mechanism of action distinct from antibiotics currently in clinical use. Our versatile and robust screening system can be easily adapted for other whole animal assays to probe a broad range of biological processes.

The aim of this study was to investigate in vitro the effects of pediocin A [a bacteriocin produced by lactic acid bacteria (LAB) Pediococcus pentosaceus FBB61] on microbial metabolism in the small and large intestine of pigs. Pediocin A was partially purified by ion exchange chromatography and added to an in vitro fermentation system. The intestinal inoculum was collected from pigs immediately after slaughter, diluted with a buffer, and dispensed into fermentation syringes and vessels of the 2 experimental groups: 1) Bac+ = cecal liquor + predigested diet + pediocin A (final concentration 160 activity units/mL); 2) Bac− = cecal liquor + predigested diet + partially purified supernatant of P. pentosaceus FBB61–2. Intestinal microbial growth was monitored using the cumulative gas production technique; the kinetics of fermentation, bacterial counts, VFA, ammonia, polyamines, and p-cresol production were analyzed. Pediocin A had almost no effects on small intestine fermentation parameters, whereas in the cecum pediocin A decreased gas production (−16%; P < 0.05), ammonia, and VFA production (−52 and −21%, respectively, after 24 h; P < 0.001) compared with the control group. Significant inhibition of clostridia and LAB occurred in cecal fermentations: the Bac+ group yielded a decreased number of clostridia and LAB in cecal fermentations (8.19 and 7.80 cfu/mL, respectively) compared with Bac− (9.32 and 8.95 cfu/mL, respectively; P < 0.001). The low clostridia counts in the pediocin-treated group may also explain the reduced concentration of the carcinogenic compound p-cresol (−88%; P < 0.01). Our results suggest that pediocin A could be an alternative to replace antibiotic growth promoters for the prophylaxis of enteric diseases and to improve production of farm animals.

Two new 2-arylbenzofuran aldehydes (1 and 2) and three known phenolic compounds (3-5) were isolated from organic extracts of Dalea spinosa. These compounds were evaluated for their intrinsic antimicrobial activity and their ability to perform as multidrug-resistance inhibitors by potentiating the activity of known antimicrobials against a variety of pathogenic microorganisms. Compound 1 and its acetate derivative 6 exhibited no direct antimicrobial activity but enhanced the effect of the weak plant antimicrobial berberine when tested against Staphylococcus aureus. Additional potentiation assays with S. aureus overexpression and knockout isogenic efflux mutants for the NorA pump were done in order to assess whether the potentiating effects were associated with inhibition of this known pump mechanism.

Publisher Summary The chapter presents a discussion on intestinal fermentation, including dietary and microbial interactions. The major benefits derived from the use of antibiotics in subtherapeutic doses in animal feeding involve: disease prevention, improved feed efficiency and increased performances, especially for the young stressed animals and where management and hygiene conditions are not excellent. In pig farming, feeding antibiotics is widely practiced around weaning, the time that represents the most challenging period a pig encounters during its life in terms of infection and abundance of stressors. Although the mechanism by which antibiotics promote growth is still under heated debate, the most reliable hypothesis relates to changes in the composition of the intestinal microflora. Some antibiotic-resistant strains of Escherichia coli have evolved compensatory mutations that preclude reversion to the sensitive state, even without selective pressure. At birth, the intestinal tract of pigs is sterile and represents a good niche for rapid proliferation of environmental bacteria. Lactobacilli, streptococci, coliforms and clostridia are the main bacterial groups that can be isolated from gastric content within the first 2–3 hours of life. Along with glucose, other metabolic fuels for the small intestine are represented by the natural polyamines: putrescine, spermidine and spermine. Another category of molecules that can play a role as microbial modulators are the prebiotics, defined as “nondigestible food ingredients” that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon.