Preliminary investigation on the microbiological quality of edible marine gastropods of the Adriatic Sea, Italy.

According to the European Legislation, marine gastropods placed unprocessed on the market must comply with the same requirements established for live bivalve molluscs but, being considered not filterfeeding and unable to concentrate fecal contaminants, they may be harvested outside the classified areas. Despite this statement, little scientific information is available on the microbiological quality of these animals. The aim of the present study was to investigate 28 batches of edible snails of the Adriatic Sea, namely Nassarius mutabilis and Bolinus brandaris, with respect to i) smell and viability, by a method here reported; ii) the bacterial component of the whole body referred to E. coli, Vibrio spp., V. parahaemolyticus, V. vulnificus, V. cholerae and V. alginolyticus. A total of 21 batches of N. mutabilis and 7 batches of B. brandaris were analyzed. Batches of both species retrieved from the primary production were all largely composed of viable animals, had saltwater/neutral smell, and showed mean value of Vibrio spp. of 5,34 and 5,79 log10 UFC g-1 in N. mutabilis and B. brandaris respectively. 47% of the batches of N. mutabilis retrieved from the market, were largely composed of dead animals, had acrid/nasty smell, and showed mean value of Vibrio spp. of 6,53 log10 UFC g-1. E. coli, V. vulnificus and V. cholerae were never detected, but all samples were positive for V. alginolyticus. One sample of B. brandaris was positive for V. parahaemolyticus genotyped by PCR at the specie level (ToxR+) and positive for the thermostable direct hemolysin gene (tdh+)

Indagine preliminare sulla componente batterica di gasteropodi marini eduli dell\u2019Adriatico

INDAGINE PRELIMINARE SULLA COMPONENTE BATTERICA DI GASTEROPODI MARINI EDULI DELL\u2019ADRIATICO Patrizia Serratore, Emanuele Zavatta, Giorgia Bignami, Luna Lorito Dipartimento di Scienze Mediche Veterinarie \u2013 Universit\ue0 di Bologna 1. Scopo Il Reg. CE 558/2010 dispone che la cattura dei gasteropodi marini, assimilati dal Reg. CE 853/2004 ai molluschi bivalvi vivi, pu\uf2 avvenire al di fuori delle aree classificare, in quanto non essendo filtratori non accumulano microrganismi contaminanti di origine fecale. Nonostante questo assunto, va rilevato che le conoscenze scientifiche sul microbiota dei gasteropodi marini eduli sono molto scarse, inoltre manca un metodo standardizzato per verificarne la vitalit\ue0 in commercio. Lo stesso Food and Veterinary Office comunitario rileva che i Controlli Ufficiali negli Stati membri risultano totalmente assenti o comunque inappropriati. Al fine di implementare le opportune pratiche ispettive, \ue8 necessario sviluppare indagini mirate sul piano della sicurezza alimentare di questi prodotti. Il presente studio offre un primo contributo di conoscenza sulla componente batterica associata a due specie dell\u2019Adriatico, Nassarius mutabilis e Bolinus brandaris, proponendo un metodo ispettivo per la verifica della vitalit\ue0. 2. Metodi Complessivamente sono stati analizzati 21 lotti di Nassarius mutabilis e 7 di Bolinus brandaris. La vitalit\ue0 \ue8 stata verificata mediante aspersione con sale da cucina, metodo messo a punto dal nostro laboratorio. Le unit\ue0 campionarie, dopo accurato risciacquo in acqua marina sterile, sono state sottoposte ad analisi batteriologiche: enumerazione di Vibrio spp., come componente autoctona, su Thiosulfate-Citrate-Bile salts-Sucrose Agar NaCl 3% finale, incubato a 20\ub0C per 3-5 gg; ricerca mirata di V. parahaemolyticus, V. vulnificus, V. cholerae e V. alginolyticus su CHROMagar Vibrio incubato a 37\ub0C per 24 h, e caratterizzazione fenotipica e genomica degli isolati (metodo interno); enumerazione di E. coli, come criterio di sicurezza, con metodo ISO 16649-2:2001. 3. Risultati Tutti i lotti acquisiti direttamente dal produttore hanno rivelato odore di salso o neutro e gli animali hanno reagito immediatamente all\u2019aspersione con sale con estroflessione del piede e movimenti attivi (Nassarius) o abbondante emissione di schiuma (Bolinus), presentando valori medi di Vibrio spp. simili, rispettivamente 5,34 log10 e 5,79 log10. Tra i lotti di Nassarius reperiti in commercio (N=17), il 47% (N=8) ha rivelato odore salso pungente o nettamente sgradevole, con reazione al sale molto scarsa o assente, presentando valori medi di Vibrio spp. pari a 6,53 log10. Tutti i campioni sono risultati negativi per E. coli, V. vulnificus e V. cholerae, ma positivi per V. alginolyticus. Un campione di Bolinus \ue8 risultato positivo per V. parahaemolyticus, con genotipo potenzialmente patogeno (ToxR+, tdh+). 4. Conclusioni I lotti di entrambe le specie reperiti alla produzione sono risultati tutti vitali, mentre il 47% dei lotti di Bolinus reperiti in commercio \ue8 risultato non conforme, in quanto composto in prevalenza o totalmente da individui morti. La mancata evidenziazione di E. coli pare giustificare il disposto del Reg. CE 558/2010. Tuttavia, i valori medi relativi a Vibrio spp. del prodotto vitale, ed ancor pi\uf9 del prodotto disvitale/morto, sono risultati superiori a quelli riscontrati nel bivalve R. philippinarum nel medesimo areale, pari a 4.69 log10. In termini di sicurezza alimentare, questa condizione di polimicrobismo in animali non filtratori necessita di ulteriori studi, sia in relazione ai target potenzialmente patogeni che in relazione ai possibili effetti del catabolismo batterico aspecifico in relazione alla produzione di amine biogene

Preliminary study on the antimicrobial susceptibility pattern related to the genotype of Vibrio vulnificus strains isolated in the north-western Adriatic Sea coastal area

V. vulnificus is a Gram-negative bacterium, commonly found in estuarine and coastal habitats, that can infect humans through seafood consumption or wound exposure. This study represents the first attempt to correlate the genotype of Vibrio vulnificus strains isolated in the north-western Adriatic Sea coastal area, with their antimicrobial susceptibility patterns. On the whole, 40 V. vulnificus strains, isolated from shellfish (n=20), different coastal water bodies (n=19), and the blood of a Carretta carretta turtle (n=1), were utilized. All strains were positive for the species-specific genes vvhA and hsp, with high variability for other markers: 55% (22 out of 40) resulted of the environmental (E) genotype (vcgE, 16S rRNA type A, CPS2 or CPS0), 10% (4 out of 40) of the clinical (C) genotype (vcgC, 16S rRNA type B, CPS1), and 35% (14 out of 40) of the mixed (M) genotype, possessing both E and C markers. The antimicrobial susceptibility was assayed by the diffusion method on agar, according to the Clinical Laboratory Standards Institute (CLSI), utilizing the following commercial disks (Oxoid): ampicillin (AMP), ampicillin- sulbactam (SAM), piperacillin (PRL), cefazolin (KZ), cefotaxime(CTX), ceftazidime( CAZ), imipenem (IPM), meropenem (MEM), amikacin (AK), gentamicin(CN), tetracycline(TE), ciprofloxacin (CIP), levofloxacin (LEV), trimethoprim-sulfamethoxazole (SXT), and chloramphenicol (C). 75% of the strains, (n=30) including all C strains, was sensitive to all the tested antibiotics, whereas E strains showed intermediate sensitivity to AK (2 strains), CIP and CAZ (1 strain), TE (1 strain) and resistance to KZ (1 strain), and 4 M strains showed I to AK

Preliminary study on the antimicrobial susceptibility pattern related to the genotype of Vibrio vulnificus strains isolated in the north-western Adriatic Sea coastal area

V. vulnificus is a Gram-negative bacterium, commonly found in estuarine and coastal habitats, that can infect humans through seafood consumption or wound exposure. This study represents the first attempt to correlate the genotype of Vibrio vulnificus strains isolated in the north-western Adriatic Sea coastal area, with their antimicrobial susceptibility patterns. On the whole, 40 V. vulnificus strains, isolated from shellfish (n=20), different coastal water bodies (n=19), and the blood of a Carretta carretta turtle (n=1), were utilized. All strains were positive for the species-specific genes vvhA and hsp, with high variability for other markers: 55% (22 out of 40) resulted of the environmental (E) genotype (vcgE, 16S rRNA type A, CPS2 or CPS0), 10% (4 out of 40) of the clinical (C) genotype (vcgC, 16S rRNA type B, CPS1), and 35% (14 out of 40) of the mixed (M) genotype, possessing both E and C markers. The antimicrobial susceptibility was assayed by the diffusion method on agar, according to the Clinical Laboratory Standards Institute (CLSI), utilizing the following commercial disks (Oxoid): ampicillin (AMP), ampicillin- sulbactam (SAM), piperacillin (PRL), cefazolin (KZ), cefotaxime(CTX), ceftazidime( CAZ), imipenem (IPM), meropenem (MEM), amikacin (AK), gentamicin(CN), tetracycline(TE), ciprofloxacin (CIP), levofloxacin (LEV), trimethoprim-sulfamethoxazole (SXT), and chloramphenicol (C). 75% of the strains, (n=30) including all C strains, was sensitive to all the tested antibiotics, whereas E strains showed intermediate sensitivity to AK (2 strains), CIP and CAZ (1 strain), TE (1 strain) and resistance to KZ (1 strain), and 4 M strains showed I to AK

Valutazione della vitalit\ue0 e della qualit\ue0 microbiologica del lumachino Nassarius mutabilis in fase di commercializzazione

The marine snail Nassarius mutabilis represent an important fishery resource of the Adriatic sea, with a production of about 2.000 ton/year. The requirements established by the European Legislation in force for fresh (live) marine gastropods are the same as for live bivalve molluscs. Therefore, in addition to ensuring compliance with the food safety criteria, live marine gastropods placed on the market may possess organoleptic characteristics associated with freshness and viability. Unfortunately standardized methods for this assessment are lacking, but some suggestions may be acquired by the scientific literature. Particularly it has been reported that body receding and the production of bubbles and mucus may be considered a response of gastropods to different aversive stimuli. Moreover, the lacking of data on the microbiota of marine gastropods makes it very difficult to evaluate their quality and shelf-life. The aim of the present study is to give a contribution of knowledge on the assessment of viability and the microbiological characteristics of Nassarius mutabilis at retail, with respect to E. coli, Vibrio spp., V. parahaemolyticus, V. vulnificus and V.cholerae

Occurrence of Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus in the clam Ruditapes Philippinarum (Adams & Reeve, 1850) from Emilia Romagna and Sardinia, Italy

Marine vibrios, Vibrio parahaemolyticus, V. vulnificus and V. cholerae are responsible of the majority of food-borne human infections by consumption of bivalve shellfish. The aim of the present study was to ascertain the occurrence of these bacteria, and their potential pathogenicity, in the Manila clam R. philippinarum from Emilia Romagna (ER) and Sardinia (SR) regions, Italy. Isolation was performed on CHROMagar\u2122 vibrio with subculture on (thiosulfate-citrate-bile salts-sucrose) Agar and m-modified-cellobiose-polymyxin bcolistin (-CPC) Agar. Suspected strains were purified, biochemically characterized and genotyped by simplex polymerase chain reaction (PCR) for the specie-specific and pathogenic gene markers: V. parahaemolyticus (toxRP, tdh and trh); V. vulnificus (vvhA, hsp, vcgC, vcgE, CPS operon allele 1, CPS operon allele 2, 16s-rRNA operon allele A, 16s-rRNA operon allele B; V. cholerae (toxRC, hlya, tcpI, tcpA, ctxA, ctxB, stn/sto). Moreover a multiplex PCR was applied to the SR bivalve shellfish, for the simultaneous detection of the three targets directly on homogenate samples, targeting the species-specific gene for V. cholerae (toxRC), V. parahaemolyticus (toxRP) and V. vulnificus (vvhA). As a result of phenotyping and genotyping of isolates, bivalve shellfish from ER resulted positive for V. parahaemolyticus (27.8%) and V. vulnificus (10.1%), but negative for V. cholerae. Shellfish from SR resulted positive for V. parahaemolyticus (30.3%), V. vulnificus (6.1%) and V. cholerae (3%). No significant differences emerged between the two areas (P>0.05)

Occurrence of Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus in the clam Ruditapes philippinarum (Adams & Reeve, 1850) from Emilia Romagna and Sardinia, Italy

Marine vibrios, Vibrio parahaemolyticus, V. vulnificus and V. cholerae are responsible of the majority of food-borne human infections by consumption of bivalve shellfish. The aim of the present study was to ascertain the occurrence of these bacteria, and their potential pathogenicity, in the Manila clam R. philippinarum from Emilia Romagna (ER) and Sardinia (SR) regions, Italy. Isolation was performed on CHROMagarTM vibrio with subculture on (thiosulfate-citrate-bile salts-sucrose) Agar and m-modified-cellobiose-polymyxin bcolistin (-CPC) Agar. Suspected strains were purified, biochemically characterized and genotyped by simplex polymerase chain reaction (PCR) for the specie-specific and pathogenic gene markers: V. parahaemolyticus (toxRP, tdh and trh); V. vulnificus (vvhA, hsp, vcgC, vcgE, CPS operon allele 1, CPS operon allele 2, 16s-rRNA operon allele A, 16s-rRNA operon allele B; V. cholerae (toxRC, hlya, tcpI, tcpA, ctxA, ctxB, stn/sto). Moreover a multiplex PCR was applied to the SR bivalve shellfish, for the simultaneous detection of the three targets directly on homogenate samples, targeting the species-specific gene for V. cholerae (toxRC), V. parahaemolyticus (toxRP) and V. vulnificus (vvhA). As a result of phenotyping and genotyping of isolates, bivalve shellfish from ER resulted positive for V. parahaemolyticus (27.8%) and V. vulnificus (10.1%), but negative for V. cholerae. Shellfish from SR resulted positive for V. parahaemolyticus (30.3%), V. vulnificus (6.1%) and V. cholerae (3%). No significant differences emerged between the two areas (P>0.05)