BACKGROUND STAPHYLOCOCCUS AUREUS PRODUCES 11 SEROTYPES OF ENDOTOXINS THAT MAY CAUSE FOOD POISONING. AIM TO DETERMINE THE PREVALENCE OF TYPE A ENTEROTOXIGENIC STAPHYLOCOCCUS AUREUS CARRIAGE AMONG FOOD SERVICE WORKERS IN CHILLAN, CHILE. MATERIAL AND METHODS PHARYNGEAL SWABS WERE OBTAINED FROM 100 FOOD SERVICE WORKERS AND WERE CULTURED IN AGAR PLATES. AFTER IDENTIFYING THE PRESENCE OF STAPHYLOCOCCUS AUREUS, DNA WAS EXTRACTED TO IDENTIFY TYPE A TOXIN BY CONVENTIONAL PCR. RESULTS THIRTY EIGHT PERCENT OF SAMPLES WERE COLONIZED WITH STAPHYLOCOCCUS AUREUS. AMONG THESE, 26% WERE TOXIN A PRODUCERS. CONCLUSIONS HALF OF THE SAMPLED WORKERS CARRIED STAPHYLOCOCCUS AUREUS AND A QUARTER OF THESE PRODUCED TYPE A ENTEROTOXIN. KEY WORDS STAPHYLOCOCCUS AUREUS; ENTEROTOXINS; FOODBORNE DISEASES

STAPHYLOCOCCUS AUREUS ES UNA BACTERIA GRAM POSITIVA PRODUCTORA ENTEROTOXINAS ESTAFILOCÓCICAS, RESPONSABLES A NIVEL MUNDIAL DE BROTES POR INTOXICACIÓN ESTAFILOCÓCICA. DETERMINAR LA GENOTIPIFICACIÓN Y PREVALENCIA DE STAPHYLOCOCCUS AUREUS ENTEROTOXIGÉNICO TIPO B, C, D Y E EN FROTIS NASOFARÍNGEOS DE MANIPULADORES DE ALIMENTOS DE CHILE. ESTE ESTUDIO SE REALIZÓ EN UNA MUESTRA DE 100 MANIPULADORES DE ALIMENTOS DE SERVICIOS DE ALIMENTACIÓN DE CHILLÁN. REALIZANDO EN UNA PRIMERA ETAPA, PREVIA FIRMA DE CONSENTIMIENTO INFORMADO, MUESTREO NASOFARÍNGEO EN LOS LUGARES DE TRABAJO. LAS MUESTRAS SE TRASLADARON A 4°C, PARA LUEGO SER INOCULADAS POR 48 HORAS A 37 °C EN PLACAS AGAR BAIRD PARKER. POSTERIOR A LAS PRUEBAS CONFIRMATIVAS DE CATALASA Y COAGULASA PARA STAPHYLOCOCCUS AUREUS, SE REALIZÓ EXTRACCIÓN DE ADN Y POSTERIOR IDENTIFICACIÓN MOLECULAR DE ENTEROTOXINA TIPO B, C, D Y E, MEDIANTE LA AMPLIFICACIÓN POR PCR CONVENCIONAL. EL 38% DE LA MUESTRA ESTABA COLONIZADA POR STAPHYLOCOCCUS AUREUS. DEL TOTAL DE PORTADORES DE LA BACTERIA SE IDENTIFICÓ QUE EL 28,9% PRODUCÍAN LA ENTEROTOXINA TIPO B Y EL 7,9% PRODUCÍAN LA ENTEROTOXINA TIPO E, DE ESTOS UN 2,6% ERA PRODUCTOR DE AMBAS ENTEROTOXINAS. NO SE DETECTÓ PRESENCIA DE LAS ENTEROTOXINAS C Y D.

ESTE MANUAL SE GENERÓ POR ADJUDICACIÓN DE FONDOS DESARROLLO A LA DOCENCIA AÑO 2020, CON EL FIN DE GENERAR INFORMACIÓN GRÁFICA DE PREPARACIONES ENTREGADAS EN SERVICIOS DE ALIMENTACIÓN, LAS QUE RESPONDEN A BASES TÉCNICAS DE CONTRATO, DONDE LA FUNCIÓN DEL NUTRICIONISTA ES VELAR POR SU CUMPLIMIENTO, PARA ASEGURAR APORTE NUTRICIONAL DE LAS PREPARACIONES ALIMENTARIAS Y GARANTIZAR RENTABILIDAD DE LA EMPRESA DE ALIMENTACIÓN.

CRONOBACTER SPP. ARE OPPORTUNISTIC PATHOGENS OF THE ENTEROBACTERIACEAE FAMILY. THE ORGANISM CAUSES INFECTIONS IN ALL AGE GROUPS, BUT THE MOST SERIOUS CASES OCCUR IN OUTBREAKS RELATED TO NEONATES WITH MENINGITIS AND NECROTIZING ENTEROCOLITIS. THE OBJECTIVE WAS TO DETERMINE THE IN SILICO AND IN VITRO PUTATIVE VIRULENCE FACTORS OF SIX CRONOBACTER SAKAZAKII STRAINS ISOLATED FROM POWDERED MILK (PM) IN THE CZECH REPUBLIC. STRAINS WERE IDENTIFIED BY MALDI-TOF MS AND WHOLE-GENOME SEQUENCING (WGS). VIRULENCE AND RESISTANCE GENES WERE DETECTED WITH THE RIDOM SEQSPHERE+ SOFTWARE TASK TEMPLATE AND THE COMPREHENSIVE ANTIBIOTIC RESISTANCE DATABASE (CARD) PLATFORM. ADHERENCE AND INVASION ABILITY WERE PERFORMED USING THE MOUSE NEUROBLASTOMA (N1E-115 ATCCCRL-2263) CELL LINE. THE CRISPR-CAS SYSTEM WAS SEARCHED WITH CRISPRCASFINDER. CORE GENOME MLST IDENTIFIED FOUR DIFFERENT SEQUENCE TYPES (ST1, ST145, ST245, AND ST297) IN SIX ISOLATES. STRAINS 13755-1B AND 1847 WERE ABLE TO ADHERE IN 2.2 AND 3.2 X 10(6) CFU/ML, WHILE 0.00073% INVASION FREQUENCY WAS DETECTED ONLY IN STRAIN 1847. BOTH STRAINS 13755-1B AND 1847 WERE POSITIVE FOR THREE (50.0%) AND FOUR VIRULENCE GENES, RESPECTIVELY. THE CPA GENE WAS NOT DETECTED. TWENTY-EIGHT GENES WERE DETECTED BY WGS AND GROUPED AS FLAGELLAR OR OUTER MEMBRANE PROTEINS, CHEMOTAXIS, HEMOLYSINS, AND INVASION, PLASMINOGEN ACTIVATOR, COLONIZATION, TRANSCRIPTIONAL REGULATOR, AND SURVIVAL IN MACROPHAGES. THE COLISTIN-RESISTANCE-ENCODING MCR-9.1 AND CEPHALOTHIN-RESIS-ENCODING BLA(CSA) GENES AND INCFII(PECLA) AND INCFIB(PCTU3) PLASMIDS WERE DETECTED. ALL STRAINS EXHIBITED CRISPR MATRICES AND FOUR OF THEM TWO TYPE I-E AND I-F MATRICES. COMBINED MOLECULAR METHODOLOGIES IMPROVE CRONOBACTER SPP. DECISION-MAKING FOR HEALTH AUTHORITIES TO PROTECT THE POPULATION.

LISTERIA MONOCYTOGENES IS CAUSING LISTERIOSIS, A RARE BUT SEVERE FOODBORNE INFECTION. LISTERIOSIS AFFECTS PREGNANT WOMEN, NEWBORNS, OLDER ADULTS, AND IMMUNOCOMPROMISED INDIVIDUALS. READY-TO-EAT (RTE) FOODS ARE THE MOST COMMON SOURCES OF TRANSMISSION OF THE PATHOGEN THIS STUDY EXPLORED THE VIRULENCE FACTORS AND ANTIBIOTIC RESISTANCE IN L. MONOCYTOGENES STRAINS ISOLATED FROM READY-TO-EAT (RTE) FOODS THROUGH IN VITRO AND IN SILICO TESTING BY WHOLE-GENOME SEQUENCING (WGS). THE OVERALL POSITIVITY OF L. MONOCYTOGENES IN RTE FOOD SAMPLES WAS 3.1% AND 14 STRAINS WERE ISOLATED. L. MONOCYTOGENES ST8, ST2763, ST1, ST3, ST5, ST7, ST9, ST14, ST193, AND ST451 SEQUENCE TYPES WERE IDENTIFIED BY AVERAGE NUCLEOTIDE IDENTITY, RIBOSOMAL MULTILOCUS SEQUENCE TYPING (RMLST), AND CORE GENOME MLST. SEVEN ISOLATES HAD SEROTYPE 1/2A, FIVE 1/2B, ONE 4B, AND ONE 1/2C. THREE STRAINS EXHIBITED IN VITRO RESISTANCE TO AMPICILLIN AND 100% OF THE STRAINS CARRIED THE FOSX, LIN, NORB, MPRF, TETA, AND TETC RESISTANCE GENES. IN ADDITION, THE ARSBC, BCRBC, AND CLPL GENES WERE DETECTED, WHICH CONFERRED RESISTANCE TO STRESS AND DISINFECTANTS. ALL STRAINS HARBORED HLYA, PRFA, AND INLA GENES ALMOST THIRTY-TWO THE SHOWED THE BSH, CLPCEP, HLY, HPT, IAP/CWHA, INLA, INLB, IPEA, LSPA, MPL, PLCA, PCLB, OAT, PDGA, AND PRFA GENES. ONE ISOLATE EXHIBITED A TYPE 11 PREMATURE STOP CODON (PMSC) IN THE INLA GENE AND ANOTHER ISOLATE A NEW MUTATION (DELETION OF A IN POSITION 819). THE INC18(REP25), INC18(REP26), AND N1011A PLASMIDS AND MGES WERE FOUND IN NINE ISOLATES. TEN ISOLATES SHOWED CAS-TYPE II-B SYSTEMS; IN ADDITION, ANTI-CRISPR ACRIIA1 AND ACRIIA3 PHAGE-ASSOCIATED SYSTEMS WERE DETECTED IN THREE GENOMES. THESE VIRULENCE AND ANTIBIOTIC RESISTANCE TRAITS IN THE STRAINS ISOLATED IN THE RTE FOODS INDICATE A POTENTIAL PUBLIC HEALTH RISK FOR CONSUMERS.