Drug resistance and susceptibility testing of Gram negative bacterial isolates from healthy cattle with different β – Lactam resistance Phenotypes from Shandong province China

The objective of this study was to evaluate the effectiveness of common antibiotics against different microorganisms in apparently healthy cattle in Shandong province and its suburb. A total of 220 nasal swab samples were collected and cultured for bacteriological evaluation. All the bacteria isolates after preliminary identification were subjected to antibiogram studies following disc diffusion method. It was found in the study that E. coli is the most commonly associated isolate (21%), followed by Klebsiella spp. (18%), Pseudomonas aeruginosa (13%), Salmonella spp. (15%), Shigella spp (12%), and Proteus spp (11%). While the antibiogram studies reveled that highest number of bacterial isolates showed resistance to Ampicillin (95%), followed by Augmentin (91%), Cefuroxime (85%) and Tetracycline (95%) of (Escherichia coli and Klebsiella spp). In the case of pseudomonas spp. and Salmonella the highest resistance was showed by Ampicillin (90%) followed by Amoxicillin + Clavulanic Acid (80%), Cefixime (90%), and Erythromycin (80%). In Shigella spp and Salmonella spp highest resistance was showed by Amoxicillin, Ceftazidime, Augmentin (60%), and Amoxicillin + Clavulanic Acid (50%). It is concluded that in vitro antibiogram studies of bacterial isolates revealed higher resistance for Ampicillin, Augmentin, Cefuroxime, Cefixime, Tetracycline, Erythromycin, and Amoxicillin + Clavulanic Acid. The high multiple Antibiotics resistance indexes (MARI) observed in all the isolates in this study ranging from 0.6 to 0.9. MARI value of >0.2 is suggests multiple antibiotic resistant bacteria and indicate presence of highly resistant bacteria.

Percentage Incidences of Bacteria in Mahseer (Tor putitora), Silver carp (Hypophthalmichthys molitrix) Fish Collected from Hatcheries and Local Markets of District Malakand and Peshawar of Khyber Pakhtunkhwa, Pakistan

Fish is the main source of animal protein for human diet. The aim of this study was to find out prevalence of pathogenic bacteria of two selected economically important fish of Pakistan namely Mahseer (Tor putitora) and Silver carp (Hypophthalmichthys molitrix). Live fish samples from hatcheries and dead fish samples from different markets of study area were randomly collected. The fish samples were analyzed for isolation, identification and prevalence of bacteria. The isolated bacteria from study fish were identified through biochemical test and about 10 species of pathogenic bacteria were identified including the pathogenic bacteria to human and fish namely, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus iniae, Serratia spp. Citrobacter spp. Stenotrophomonas spp. Bacillus spp. and Salmonella spp. The bacterial percentage frequency of occurrence in Silver carp and Mahseer fish showed Pseudomonas aeruginosa 21.42%, Staphylococcus epidermidis 17.85%, Escherichia coli 11.90%, Staphylococcus aureus 9.52%, Citrobacter spp. 9.52%, Serratia spp. 8.33%, Streptococcus iniae 7.14%, Stenotrophomonas spp. 5.95%, Bacillus spp. 4.76% and Salmonella spp. 3.57%. The study revealed that Fish samples of Mahseer and Silver carp that were collected from markets have found more isolates (10 bacterial species) than did the fresh fish pond samples (03 bacterial species) of hatcheries. The occurrence of pathogenic bacteria in study fish showed risk factor for public health consumers.

A duplex real-time NASBA assay targeting serotype-specific gene for rapid detection of viable S. enterica serovar Paratyphi C in retail foods of animal origin

Salmonella enterica serovars Paratyphi C is highly adapted to humans and can cause a typhoid-like disease with high mortality rates. In this study, three serovar-specific genes were determined for S. Paratyphi C, SPC_0871，SPC_0872, and SPC_0908, by comparative genomics method. Based on SPC_0908 and xcd gene for testing Salmonella spp., we have developed a duplex real-time nucleic acid sequence-based amplification (real-time NASBA) with molecular beacon approach for simultaneous detection of viable cells of Salmonella spp. and serotype Paratyphi C. The test selectively and consistently detected 53 Salmonella spp. (representing 31 serotypes) and 18 non-Salmonella strains. Additionally, the method showed high resistance to interference by natural background flora in pork and chicken samples. The sensitivity of the established approach was determined to be 4.89 CFU/25 g in artificially contaminated pork and chicken samples after pre-enrichment. We propose this NASBA-based protocol as a potential detection method for Salmonella spp. and serotype Paratyphi C in food of animal origin.

Colistin Resistance Mechanisms in Human Salmonella enterica Strains Isolated by the National Surveillance Enter-Net Italia (2016–2018)

Background: A collection of human-epidemiologically unrelated S. enterica strains collected over a 3-year period (2016 to 2018) in Italy by the national surveillance Enter-Net Italia was analysed. Methods: Antimicrobial susceptibility tests, including the determination of minimal inhibitory concentrations (MICs) for colistin, were performed. Colistin resistant strains were analysed by PCR to detect mobile colistin resistance (mcr) genes. In mcr-negative S. enterica serovar Enteritidis strains, chromosomal mutations potentially involved in colistin resistance were identified by a genomic approach. Results: The prevalence of colistin-resistant S. enterica strains was 7.7%, the majority (87.5%) were S. Enteritidis. mcr genes were identified only in one strain, a S. Typhimurium monophasic variant, positive for both mcr-1.1 and mcr-5.1 genes in an IncHI2 ST4 plasmid. Several chromosomal mutations were identified in the colistin-resistant mcr-negative S. Enteritidis strains in proteins involved in lipopolysaccharide and outer membrane synthesis and modification (RfbN, LolB, ZraR) and in a component of a multidrug efflux pump (MdsC). These mutated proteins were defined as possible candidates for colistin resistance in mcr-negative S. Enteritidis of our collection. Conclusions: The colistin national surveillance in Salmonella spp. in humans, implemented with genomic-based surveillance, permitted to monitor colistin resistance, determining the prevalence of mcr determinants and the study of new candidate mechanisms for colistin resistance.

One Health Approach for combating Antimicrobial Resistance in Animals

Antimicrobial resistance (AMR) is an increasing hazard to human and animal health that necessitates an international response. Surveillance methods in high-income nations aided in the development of measures to combat AMR in animals. Demand for meat is increasing in countries making it critical to implement anti-AMR initiatives. Surveillance of AMR, on the other hand, is at best in its infancy, and the current evidence base for informing policymakers is geographically disparate. All of the isolates had high rates of AMR to medicines that are critical/highly important in human and animal medicine. A higher incidence of AMR was found in poultry farms. Our findings show that AMR, including MDR, is common in coli, Salmonella spp., commonly found in poultry. The study promotes the development of national policies, programs, and additional research based on a "One Health" approach that helps humans and animals, as well as the environment.

Safety assessment of traditional Plaisentif cheese

Traditional foods are gaining more and more market due to consumers’ increasing willingness to buy products linked to national cultures: among these products, cheese plays an important role. Plaisentif is a traditional Piedmont cheese, only made during violets blooming season. The aim of this work is to evaluate the safety of this cheese, taking into account the EU Regulations. Microbiological hazards as well chemical, biogenic amines and mycotoxins, analysis were investigated. Salmonella spp. and Listeria monocytogenes were never detected in cheeses after ripening. Biogenic amines were present in very low quantities. Ochratoxin A was never detected and patulin was detected in over one cheese during the two years of sampling. This is the first attempt to characterize traditional Plaisentif cheese from a safety point of view. All the information acquired can be held as a necessary basis for reinforcing the culture of traditional products, for economic opportunities in mountainous regions and for safeguarding traditions and cultural identities.

An Evaluation of the Pathogenic Potential, and the Antimicrobial Resistance, of Salmonella Strains Isolated from Mussels

Salmonella spp. and antimicrobial resistant microorganisms are two of the most important health issues worldwide. In the present study, strains naturally isolated from mussels harvested in Galicia (one of the main production areas in the world), were genetically characterized attending to the presence of virulence and antimicrobial resistance genes. Additionally, the antimicrobial profile was also determined phenotypically. Strains presenting several virulence genes were isolated but lacked all the antimicrobial resistance genes analyzed. The fact that some of these strains presented multidrug resistance, highlighted the possibility of bearing different genes than those analyzed, or resistance based on completely different mechanisms. The current study highlights the importance of constant surveillance in order to improve the safety of foods.

Inhibition of Zoonotic Pathogens Naturally Found in Pig Manure by Black Soldier Fly Larvae and Their Intestine Bacteria

Black soldier fly (BSF) larvae are often exposed to organic waste which harbors abundant zoonotic pathogens. We investigated the ability of BSF larvae to inhibit the zoonotic pathogens naturally found in pig manure. The zoonotic pathogens populations were detected by using selective medium during the conversion. Results showed that the viability of the zoonotic pathogens in pig manure was significantly affected. After eight days of conversion, the Coliform populations were undetected, and Staphylococcus aureus and Salmonella spp. decreased significantly on the eighth day. Antimicrobial assays of the purified recombinant defensin-like peptide 4 (DLP4) showed that this peptide exhibits inhibitory activity against S. aureus, Salmonella enterica serovar typhimurium, and Escherichia coli in vitro. Bacteria BSF-CL and BSF-F were isolated from the larvae gut, and both inhibited the growth of S. aureus and E. coli, but Salmonella spp. was sensitive to the BSF-CL strain (but not to the BSF-F strain). The results from our experiments indicate that BSF larvae are capable of functionally inhibiting potential zoonotic pathogens in pig manure through a variety of mechanisms including antimicrobial peptides expression and the gut associate microorganisms. This study provides a theoretical basis for further study on the combined mechanism of BSF larvae immunity and its gut microbes against the zoonotic pathogens in pig manure.

Kinome Analysis of Cattle Peripheral Lymph Nodes to Elucidate Differential Response to Salmonella spp.

Salmonella spp., contained within the peripheral lymph nodes (PLNs) of cattle, represents a significant source of contamination of ground beef. Herein is the first report where species-specific kinome peptide arrays designed for bovine biology were used to further the understanding of Salmonella spp. within these PLNs. For the purpose of this research, multiple comparisons of sub-iliac lymph nodes were made to include nodes from feedlot cattle that were infected with Salmonella spp. to those that were non-infected; seasonal differences in feedlot cattle harvested in either August or January; cull dairy cows compared to feedlot cattle; and PLNs from cattle experimentally inoculated with Salmonella spp. versus naturally infected animals. The first comparison of Salmonella-positive and -negative PLNs found that considering the kinotypes for these animals, the major distinguishing difference was not the presence or absence of Salmonella spp. in the PLNs but the concentration. Further, the majority of pathways activated were directly related to immune responses including innate immunity, thus Salmonella spp. within the PLNs activates the immune system in that node. Results from the comparison of feedlot cattle and cull dairy cows suggests that a Salmonella spp.-negative animal, regardless of type, has a more consistent kinome profile than that of a Salmonella spp.-positive animal and that the differences between feedlot and cull dairy cattle are only pronounced when the PLNs are Salmonella spp. positive. PLNs collected in the winter showed a much more consistent kinome profile, regardless of Salmonella status, suggesting that in the winter these cattle are similar, and this is not affected by the presence of Salmonella spp., whereas significant variability among kinotypes was observed for PLNs collected in the summer. The most distinct clustering of kinotypes observed in this study was related to how the animal was infected with Salmonella spp. There were significant differences in the phosphorylation state of the immune response peptides between experimentally and naturally infected animals, suggesting that the immune system is activated in a significantly different manner when comparing these routes of infection. Increasing our understanding of Salmonella spp. within cattle, and specifically within the PLNs, will ultimately help design effective pre-harvest intervention strategies as well as appropriate experimentation to validate those technologies.