Carriage of Staphylococcus aureus among food handlers: An ongoing challenge in public health

Staphylococcus aureus is a commensal bacterium known to colonize the skin, nares, and gastrointestinal tract of humans. Asymptomatic workers can contaminate food via manual contact or through respiratory secretions thus becoming the source of staphylococcal food poisoning. This gastrointestinal intoxication occurs after the ingestion of food contaminated by enterotoxin-producing Staphylococcus aureus. Although most individuals overcome the infection without medical assistance and make a full recovery, in rare cases the infection can be life-threatening. Hence, Staphylococcus aureus food contamination represents a serious problem for both the food industry and healthcare systems. In the last few decades, many studies have investigated the prevalence of carriers among food handlers. We present an overview of all investigations carried out on nasal carriers working in different food industry settings highlighting the risk associated with cross-contamination

Prevalence, Antibiotic-Resistance, and Replicon-Typing of Salmonella Strains among Serovars Mainly Isolated from Food Chain in Marche Region, Italy

Nontyphoidal salmonellosis (NTS) is the second most commonly reported gastrointesti nal infection in humans and an important cause of food-borne outbreaks in Europe. The use of antimicrobial agents for animals, plants, and food production contributes to the development of antibiotic-resistant Salmonella strains that are transmissible to humans through food. The aim of this study was to investigate the presence and the potential dissemination of multidrug-resistant (MDR) Salmonella strains isolated in the Marche Region (Central Italy) via the food chain. Strains were isolated from different sources: food, human, food animal/livestock, and the food-processing environment. Among them, we selected MDR strains to perform their further characterization in terms of resistance to tetracycline agent, carriage of tet genes, and plasmid profiles. Tetracycline resistance genes were detected by PCR and plasmid replicons by PCR-based replicon typing (PBRT). A total of 102 MDR Salmonella strains were selected among the most prevalent serovars: S. Infantis (n = 36/102), S. Derby (n = 20/102), S. Typhimurium (n = 18/102), and a monophasic variant of S. Typhimurium (MVST, n = 28/102). Resistance to sulfisoxazole (86%) and tetracycline (81%) were the most common, followed by ampicillin (76%). FIIS was the most predominant replicon (17%), followed by FII (11%) and FIB (11%) belonging to the IncF incompatibility group. Concerning the characterization of tet genes, tetB was the most frequently detected (27/89), followed by tetA (10/89), tetG (5/89), and tetM (1/89). This study showed the potential risk associated with the MDR Salmonella strains circulating along the food chain. Hence, epidemiological surveillance supported by molecular typing could be a very useful tool to prevent transmission of resistant Salmonella from food to humans, in line with the One Health approach

Evaluation of a kDNA-Based qPCR Assay for the Detection and Quantification of Old World Leishmania Species

none10noThe parasite protozoan Leishmania, the causative agent of leishmaniasis, includes two subgenera of medical interest: Leishmania (Leishmania) and Leishmania (Viannia). Parasite species detection and characterization is crucial to choose treatment protocols and to monitor the disease evolution. Molecular approaches can speed up and simplify the diagnostic process. In particular, several molecular assays target the mitochondrial DNA minicircle network (kDNA) that characterizes the Leishmania genus. We previously proposed a qPCR assay targeting kDNA, followed by high resolution melt (HRM) analysis (qPCR-ML) to distinguish L. (L.) infantum and L. (L.) amazonensis from L. Viannia species. Successively, this assay has been integrated with other qPCR assays, to differentiate L. (L.) infantum, L. (L.) amazonensis and L. (L.) mexicana. In this work, we tested the applicability of our qPCR-ML assay on L. (L.) donovani, L. (L.) major, L. (L.) tropica and L. (L.) aethiopica, showing that the qPCR-ML assay can also amplify Old World species, different from L. (L.) infantum, with good quantification limits (1 × 10-4-1 × 10-6 ng/pcr tube). Moreover, we evaluated 11 L. (L.) infantum strains/isolates, evidencing the variability of the kDNA minicircle target molecules among the strains/isolates of the same species, and pointing out the possibility of quantification using different strains as reference. Taken together, these data account for the consideration of qPCR-ML as a quantitative pan-Leishmania assay.openCeccarelli, Marcello; Buffi, Gloria; Diotallevi, Aurora; Andreoni, Francesca; Bencardino, Daniela; Vitale, Fabrizio; Castelli, Germano; Bruno, Federica; Magnani, Mauro; Galluzzi, LucaCeccarelli, Marcello; Buffi, Gloria; Diotallevi, Aurora; Andreoni, Francesca; Bencardino, Daniela; Vitale, Fabrizio; Castelli, Germano; Bruno, Federica; Magnani, Mauro; Galluzzi, Luc

Rapid monitoring of SARS-CoV-2 variants of concern through high-resolution melt analysis

The current global pandemic of COVID-19 is characterized by waves of infection due to the emergence of new SARS-CoV-2 variants carrying mutations on the Spike (S) protein gene. Since autumn 2020 many Variants of Concern (VOC) have been reported: Alpha/B.1.1.7, Beta/B.1.351, Gamma/P.1, Delta/B.1.617.2, Omicron/B.1.1.529, and sublineages. Surveillance of genomic variants is currently based on whole-genome sequencing (WGS) of viral genomes on a random fraction of samples positive to molecular tests. WGS involves high costs, extended analysis time, specialized staff, and expensive instruments compared to a PCR-based test. To rapidly identify the VOCs in positive samples, six assays based on real-time PCR and high-resolution melting (HRM) were designed on the S gene and applied to 120 oro/nasopharyngeal swab samples collected from October 2020 to June 2022 (106 positive and 14 negative samples). Overall, the assays showed 100% specificity and sensitivity compared with commercial PCR tests for COVID-19. Moreover, 104 samples out of 106 (98.1%) were correctly identified as follows: 8 Wuhan (wild type), 12 Alpha, 23 Delta, 46 Omicron BA.1/BA.1.1, 15 Omicron BA.2/BA.4/BA.5. With our lab equipment, about 10 samples can be processed every 3 h at the cost of less than € 10 ($ 10.60) per sample, including RNA extraction. The implementation of this approach could help local epidemiological surveillance and clinical decision-making

Development and Application of a High Resolution Melt (HRM) based test for the Rapid Screening of Leishmania infantum Genotypes

INTRODUCTION Leishmaniasis includes anthropo zoonotic infectious diseases caused by a protozoan of the Leishmania genus, associated with different clinical manifestations, affecting both humans and other vertebrates, including dogs The Mediterranean basin, including Italy, is considered an endemic area for both visceral and cutaneous leishmaniasis caused by L infantum The multi locus enzyme electrophoresis ( based on the electrophoretic mobility of several enzymes from promastigotes cultures, is considered the reference method for parasite typing Through this method, about 45 L infantum zymodemes (also termed MON) have been identified in humans in the Mediterranean basin 1 Among these, L infantum MON 1 is the most widespread, representing about 70 of all identified strains In Italy, canine infections showed a high prevalence of MON 1 91 with the remaining composed almost exclusively of MON 72 2 Since MLEE technique is cumbersome, time consuming and requires parasites isolation, several biomolecular approaches have been developed In particular, we identified the SNP 390 T>G in malic enzyme ( gene as a potential marker to differentiate the most common L infantum genotype, i e 390 T (corresponding to zymodemes MON 1 72 201 from all others. AIMS This study aimed to develop a Rapid Genotype Screening ( assay for L infantum genetic characterization in clinical samples using high resolution melt ( analysis, exploiting the polymorphism 390 T>G in the ME gene

Aplicación de métodos multicriterio para el soporte de selección de proveedores en la empresa Provemel Ltda

Hoy en día, la logística comercial requiere decisiones estratégicas que deben estar bien fundamentadas con la mayor cantidad de información posible para lograr las ventajas competitivas que las organizaciones necesitan para tener éxito. La selección de proveedores es una parte indispensable de cualquier estrategia de la organización, ya que proporcionan las materias primas necesarias para que comience el proceso de producción. Provemel Ltda tuvo diferentes problemas en términos de proveedores que les impidieron alcanzar tales ventajas competitivas en el mercado. Durante mucho tiempo, la empresa mantuvo una producción ineficiente porque el proveedor real vende los materiales a un alto costo y no siempre tienen el material disponible. Para generar mejores resultados a lo largo de la cadena de suministro de la empresa ya que se entiende que esto debe ser una armonización de los procesos internos entre el comprador y el proveedor, y mejorar el desempeño de la empresa respaldada en la utilidad, calidad, desempeño, tiempo y servicio de lo mismo. Este trabajo presenta un análisis de proveedores enfocado en la aplicación de dos métodos multicriterios. Uno de estos métodos de multicriterios es AHP Difuso que facilita la toma de decisiones en problemáticas donde se involucran varios criterios, el otro es TOPSIS, que se estructura en un algoritmo que genera mejores alternativas para cada criterio. Además, presenta un modelo de orden de pedido que se adapta a las necesidades de la empresa. A través del análisis y la implementación de estos métodos multicriterios, se propuso una solución para la selección de los proveedores, que permite modelar las preferencias de los especialistas y tomar la mejor decisión.Nowadays, business logistics requires strategic decisions that must be well founded with as much information as possible in order to achieve the competitive advantages that organizations need to succeed in the market. The supplier selection is an indispensable part of any organizations strategy, because they provide the raw materials needed for the production process to start. Provemel Ltda had different problems in terms of suppliers which prevented them to reach such competitive advantages in the market. For a long time, the company maintained an inefficient production because the actual supplier sells the materials at a high cost and they do not always have the material available. In order to generate better results along the supply chain of the company as it is understood that this should be a harmonization of the internal processes between the buyer and the supplier, and improve the performance of the company supported in the utility, quality, performance, time and service of the same. In order to take into account the different criteria considered relevant by the company, in this work is presented a supplier analysis focused on the application of two multicriteria methods selected after a deep bibliographical review. One of these multicriteria method is Fuzzy AHP (Hierarchical Analysis Process) that facilitates the decision making in problematics where several criteria are involved. With the help of an expert committee of the company and the information found in the literature, the criteria to be taken into account in the analysis was selected. With this methodology the criteria and their weight was given. The other method is TOPSIS (Technique for Order Performance by Similarity to Ideal Solution), which is structured in an algorithm in which each possible supplier (previously selected by contacting and asking for a quotation to different companies with the aluminum rod 6063HEX 7/16” T5 X3 m in their portfolio), is evaluated according to the criteria and giving as a result the supplier that better fits to the company needs, according to the criteria previously selected and weighted. Additional to this, given that the company does not follows an specific model of order, a deep analysis was made to determine that the best option for the company was to follow an S,T model of order, reason why this work also propose to the company a way to order, avoiding delays and reducing costs.Ingeniero (a) IndustrialPregrad

Development and application of a MLST panel for the identification of informative polymorphisms in Leishmania infantum strains in the Mediterranean region

Background. Leishmaniasis is a zoonotic disease endemic in the Mediterranean region, where the causative agent of human and canine infection is Leishmania infantum. The spread of leishmaniasis is associated with population movements, ecology of phlebotomine vectors, and reservoir host. We used multilocus sequence typing (MLST) to explore the genetic variability of L. infantum strains in the Mediterranean region, including the borderline territory of Pantelleria island, and identify informative polymorphisms for rapid identification of genotypes through high-resolution melt (HRM)-based assays. Material and Methods. A customized sequencing panel targeting 14 housekeeping genes was designed and MLST analysis was performed using the Ion Torrent S5 on 9 L. infantum strains/isolates: 5 canine isolates (3 from Pantelleria Island and 2 from central Italy), and 4 human isolates/strains from Tunisia, France, central and southern Italy. MLST results and in silico analysis of sequences available in Genbank allowed to select two informative polymorphisms on ME and GPI genes (390T/G and 1834A/G, respectively) used to develop two HRM-based assays for fast screening of 28 clinical samples. Results. The MLST analysis identified a single L. infantum clonal complex regardless of the geographic origin or host (human or canine), except for the human isolate from central Italy that showed polymorphisms in 11 out of 14 housekeeping genes, and clustered independently in a molecular phylogenetic analysis. Successively, the screening through HRM-based assays of 28 clinical samples from central/south Italy and Pantelleria island allowed to identify 6 diploid sequence types (DSTs). Interestingly, the sequence type 390T/1834A was found only in Pantelleria island (prevalence 75%). Conclusion. This study represents a description of the genetic variability of L. infantum through a first approach based on MLST and then by HRM analysis on selected polymorphisms. The HRM assays could be used as fast and cheap tools for epidemiological surveillance of L. infantum

Microbiological evaluation of ready-to-eat iceberg lettuce during shelf-life and effectiveness of household washing methods

The aim of this study was to assess the microbiological quality of ready-to-eat (RTE) iceberg lettuce. Our investigation was based on the consumption tendency of university students considered a target market for this product. A total of 78 RTE samples were collected from chain supermarkets and analysed for the enumeration of aerobic mesophilic count (AMC), Escherichia coli and the detection of Salmonella spp. and Listeria monocytogenes. All samples were negative for the presence of pathogens. The mean value of AMC at the beginning, in the middle and after the expiration date was: 6.88, 8.51 and 8.72 log CFU g-1, respectively. The same investigation was performed on 12 samples of fresh iceberg lettuce samples. No pathogens were found and the mean value of AMC was lower than the RTE category (5.73 log CFU g-1; P<0.05). The effectiveness of 5 washing methods was determined on 15 samples of both fresh and RTE iceberg lettuce. Samples were washed for 15’ and 30’ in tap water (500 mL), tap water with NaCl (4 g/500 mL), tap water with bicarbonate (8 g/500 mL), tap water with vinegar (10 mL/500 mL) and tap water with chlorine-based disinfectant (10 mL/500 mL). A significant bacterial load reduction was recorded for vinegar and disinfectant after 30’ and 15’, respectively. Overall, these results showed that RTE iceberg lettuce is more contaminated than the fresh product. Also, the consumption in the first few days of packaging and after washing with disinfectants reduces the risk for health consumers