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As part of a standardization project, an interlaboratory trial including 15 laboratories from 13 European countries was conducted to evaluate the performance of a noproprietary polymerase chain reaction (PCR)-based method for the detection of Salmonella on artificially contaminated chicken rinse and pig swab samples. The 3 levels were 1-10, 10-100, and 100-1000 colony-forming units (CFU)/100 mL. Sample preparations, including inoculation and pre-enrichment in buffered peptone water (BPW), were performed centrally in a German laboratory; the pre-PCR sample preparation (by a resin-based method) and PCR assay (gel electrophoresis detection) were performed by the receiving laboratories. Aliquots of BPW enrichment cultures were sent to the participants, who analyzed them using a thermal lysis procedure followed by a validated Salmonella-specific PCR assay. The results were reported as negative or positive. Outlier results caused, for example, by gross departures from the experimental protocol, were omitted from the analysis. For both the chicken rinse and the pig swab samples, the diagnostic sensitivity was 100%, with 100% accordance (repeatability) and concordance (reproducibility). The diagnostic specificity was 80.1% (with 85.7% accordance and 67.5% concordance) for chicken rinse, and 91.7% (with 100% accordance and 83.3% concordance) for pig swab. Thus, the interlaboratory variation due to personnel, reagents, thermal cyclers, etc., did not affect the performance of the method, which will be proposed as part of a developing international PCR standard.

This study was aimed at determining the prevalence and characterising the strains of Salmonella species in various captive reptiles in the Czech Republic. A total of 211 samples of cloacal swabs from lizards, chelonians and snakes, and 14 swabs from terraria surfaces were collected between November 2014 and July 2015. After isolation according to the reference method (EN ISO), Salmonella spp. isolates were characterised using serotyping and macrorestriction analysis followed by pulsed field gel electrophoresis and antimicrobial susceptibility testing. Altogether, 39 isolates were obtained from 29 (19%) reptiles and from terraria surfaces. Among the different reptilian species, Salmonella spp. were found in 22 (25.6%) lizards, three (17.6%) snakes and four (8%) chelonians with 31 isolates classified as Salmonella enterica subspecies enterica and eight isolates classified as Salmonella enterica subsp. salamae. In total, 14 different serotypes were detected, with the most frequent serotypes being Salmonella Oranienburg, S. Fluntern, S. Tennessee and S. Cotham. Resistance to one antimicrobial agent (ampicillin, tetracycline or streptomycin) was detected in five isolates. The results of the macrorestriction analysis within the serotype groups showed varying level of heterogeneity. This study confirms that reptiles kept as pets can be both carriers and reservoirs of Salmonella spp., and that they can harbour various serotypes with intermittent excretion of the bacteria in faeces. Half of the detected serotypes have been involved in human reptileassociated salmonellosis cases in the past. S. enterica subsp. salamae serotype O:1,13,23;H:z29;H:1,5, monophasic S. enterica subsp. salamae serotype O:40;H:g,t;H:- and its biphasic form (S. enterica subsp. salamae serotype O:40;H:g,t;H:1,5) have apparently been isolated from reptiles for the first time in this study. [ABSTRACT FROM AUTHOR]

Abstract: In this study we examined the extent of biofilm formation in field strains of Salmonella enterica serovar Typhimurium (S. Typhimurium), an important foodborne pathogen. Ninety-four field strains of S. Typhimurium were tested for their ability to form biofilm and components contributing to its formation. Most S. Typhimurium strains were highly capable of biofilm formation except for strains of phage type DT2 originating from pigeons. The most efficient biofilm forming strains were those of phage type DT104 positive for Salmonella genomic island 1 (SGI1). A comparison of SGI1 positive and negative strains indicated that the increased biofilm formation of SGI1 positive strains was associated with the presence of this genomic island. Finally, in five strains we found an alternative strategy of biofilm formation independent of curli fimbriae and cellulose production but solely dependent on an overproduction of capsular polysaccharide. Due to a mucoid and brown appearance on Congo Red agar we designated these strains as belonging to the SBAM (smooth brown and mucoid) morphotype. [Copyright &y& Elsevier]