ABSTRACT
AIMS: To provide an epidemiologic interpretation of a suspected outbreak of food poisoning caused by Salmonella enterica subspecies enterica serovar Berta strains isolated from humans and from the leftovers of the implicated foods (cream, dairy-based desserts and eggs). METHODS AND RESULTS: We have correlated the similarity between the strains through genotyping with Pulsed Field Gel Electrophoresis (PFGE), studying antimicrobial sensitivity patterns and epidemiological investigation. The clonal origin of the outbreak was confirmed by all laboratory tests. PFGE analysis of the restriction profiles obtained with XbaI and SpeI revealed a certainly correlation from the strains isolated from the various sources, while the antimicrobial sensitivity pattern was the same in all cases, with all strains sensitive to all antibiotics tested. CONCLUSIONS: Poor hygiene conditions in the facility concerned, lack of hygiene in food handling, high summer temperatures and positive cultures from asymptomatic staff could all be implicated in the infection, with food being the means through which it spread. SIGNIFICANCE AND IMPACT OF THE STUDY: This study describes the first outbreak of food poisoning caused by Salmonella enterica subspecies enterica serovar Berta (Salmonella Berta) reported in Italy. It confirms the importance of correlating epidemiological investigations with genotyping and phenotyping to understand the dynamics of infection.
Subject(s)
Disease Outbreaks , Salmonella Food Poisoning/microbiology , Salmonella enterica/classification , Food Handling , Humans , Italy/epidemiology , Salmonella Food Poisoning/epidemiology , Salmonella enterica/geneticsABSTRACT
The aim of this study was to assess the possible circulation of genetic resistance determinants and chromosomal point mutations in quinolone-resistant Escherichia coli isolated from livestock from central Italy. Forty-nine E. coli isolates were recovered from animals during the surveillance activities of the Istituto Zooprofilattico Abruzzo e Molise (IZSA&M), Italy, over 2 years. The plasmid resistance determinants and point mutations in DNA gyrase and topoisomerase IV were characterized by PCR and DNA sequencing. Of the 49 E. coli isolates, 34 were resistant to nalidixic acid, 4 to ciprofloxacin and 11 to nalidixic acid, ciprofloxacin and enrofloxacin. Chromosomal point mutations were found in gyrA gene (Ser83Leu and Asp87Asn) and gyrB (Gln434His, Lys444Arg and Gly435Val). We also report the simultaneous presence of qnrS1 quinolone resistance determinant, dfrA1-aadA22 gene cassettes and amino acid substitution Ser83Leu in the gyrA gene in an E. coli strain resistant only to nalidixic acid.
Subject(s)
Anti-Infective Agents/pharmacology , Cattle/microbiology , Chickens/microbiology , Ciprofloxacin/pharmacology , Drug Resistance, Bacterial , Escherichia coli/drug effects , Nalidixic Acid/pharmacology , Rabbits/microbiology , Sheep/microbiology , Animals , Blotting, Southern , Chromosomes, Bacterial/genetics , Escherichia coli/isolation & purification , Escherichia coli Proteins/genetics , Italy , Plasmids/genetics , Polymerase Chain ReactionABSTRACT
Brucella field strains were identified using molecular techniques. A polymerase chain reaction (PCR) method, based on amplification of the insertion sequence IS711, was used to identify the isolates at species level. Subsequently, restriction fragment length polymorphism analysis of the omp2a and omp2b genes was used to assign the Brucella species to the different biovars. A total of 248 field strains were processed and complete agreement was obtained with the species/biovar identifications made by conventional bacteriological methods. PCR based tests were more rapid and proved valuable in overcoming some of the drawbacks of conventional methods.
