Pietro Di Taranto

Between 2024 and 2025, 345 official dairy product samples were collected by Local veterinary Authorities of Foggia and analysed at Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata. Specifically, 119 samples were tested for Salmonella detection (ISO 6579-1:2017/Amd 1:2020); 172 for Listeria monocytogenes (Lm) detection (ISO 11290-1:2017); 119 for Lm enumeration (ISO 11290-2:2017); 133 for Shiga toxin-producing Escherichia coli (STEC) detection (ISO/TS 13136:2012); 188 for β-glucuronidase-positive E. coli enumeration (ISO 16649-2:2001); 189 for coagulase-positive staphylococci (CoPS) enumeration (ISO 6888-2:2023); 59 for staphylococcal enterotoxins detection (ISO 19020:2017) and 54 for aerobic microorganisms (AM) at 30°C enumeration (ISO 4833-1:2022). Presumptive colonies of Salmonella and Lm were confirmed by MALDI-TOF MS. Confirmed Salmonella isolates were serotyped (ISO/TR 6579-3:2014) and tested for antimicrobial susceptibility by broth microdilution (Sensititre™ EUVSEC), following Commission Implementing Decision (EU) 2020/1729. Minimum inhibitory concentrations were interpreted according to EUCAST epidemiological cut-off values. CoPS were subjected to PCR for the detection of staphylococcal enterotoxin genes (sea to see and ser) (AFSSA EU RL Protocol). DNA from the bacterial strains was purified using the MagMAX™ CORE Nucleic Acid Purification Kit (Thermo Fisher Scientific). Sequencing libraries were prepared according to the Illumina protocol and sequenced on an Illumina MiSeq platform. The obtained reads were assembled de novo using SPAdes. Bioinformatic analysis were performed using AMRFinderPlus for the identification of antimicrobial resistance (AMR) genes and virulence factors. Overall, 31 samples (9.0%, 31/345) were found to be non-compliant. Non-compliances involved the enumeration of AM at 30°C (18.5%, 10/54), E. coli (3.7%, 7/188), CoPS (2.1%, 4/189) and the detection of Salmonella (1.7%, 2/119), STEC (0.8%, 1/133) and Lm (4.1%, 7/172). Both Salmonella isolates were identified as S. Apeyeme. One isolate was susceptible to all antimicrobials tested, whereas the other showed a multidrug-resistant profile, with resistance to azithromycin, tigecycline, colistin and tetracycline. AMR was confirmed by the detection of mph(A), tet(X3), mcr-1 and tet(A) genes. Both Salmonella strains harbored virulence-associated genes (invA, avrA, pipA, sseK2, iroB, iroC, lpfB, icmF, sciR, sinH) implicated in host cell invasion, intracellular survival, iron acquisition and intestinal colonisation. The STEC isolate was identified as serotype O55:H12 belonging to sequence type (ST) 101 and harbored the stx1 virulence gene. AMR genes detected included (blaTEM-1, sul2, aph(3'')-Ib) conferring resistance to β-lactams, sulfonamides and streptomycin. Lm strains belonged to Lineage I and were assigned to ST1 (3/7, 42.8%), ST6 (2/7, 28.6%) and ST200 (2/7, 28.6%). All Lm strains carried the virulence genes (inlA, inlB, lntA, inlC, inlP) associated with host-cell invasion, immune modulation, intracellular spread and placental colonisation. Among CoPS, the sea gene was detected in one isolate. This study highlights the importance of microbiological surveillance and genomic characterisation of foodborne pathogens to support risk assessment and strengthen food safety measures along the dairy production chain. The detection of pathogens carrying relevant AMR and virulence determinants underscores their potential threat to public health.

Poultry is the main reservoir of Campylobacter spp. and most human cases result from consuming undercooked poultry or handling raw meat. In 2022, a total of 55 samples, including neck skin, cecal contents, and processing waters, were collected at two poultry slaughterhouses in Italy and analysed according to ISO 10272-2:2017 at the Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata laboratories. Overall, 51/55 (92.72%) samples tested positive for Campylobacter. Among the isolates, 64.71% were identified as C. coli, and 35.29% as C. jejuni. Phenotypic and genotypic analysis were performed to assess antimicrobial resistance and virulence characteristics. All C. jejuni isolates and 72.72% of C. coli showed resistance to fluoroquinolones. Resistances to tetracycline and carbapenem were observed in 60.78% and 45.09% of isolates, respectively. Genomic analysis confirmed the presence of the tet(O) gene, conferring tetracycline resistance. In addition, OXA-450 and OXA-466 genes, conferring beta-lactam resistance, were detected in 78.43% and 3.92% of isolates. Virulence-associated genes were detected. Specifically, the ciaB gene was found in 50/51 (98.04%) of isolates, whereas jlpA, cdtA, cdtB, and ctdC genes were exclusively identified in C. jejuni strains. The high prevalence of pathogenic and antimicrobial-resistant Campylobacter strains highlights the need for strengthened control measures along the poultry production chain.

The circulation of viruses of medical and veterinary importance is monitored to evaluate risks to both human and animal health. Among the species most commonly used in surveillance programs, the wild boar (Sus scrofa) plays a key role due to its high population density and its contacts with rural swine herds in the areas under investigation. In the present study, molecular (real-time PCR) and serological analyses were conducted on wild boar samples collected in the regions of Apulia, Basilicata, Campania, and Calabria. Specifically, molecular detection was applied to IAVs, FLVs, and Porcine PCV-2, while serological testing was used to assess exposure to IAVs, FLVs, and ADV. Serological results showed an 8.31% positivity for IAVs, whereas viral presence detected by PCR was 1.17%. No active infections were detected for WNV, with only a single seropositive sample (0.30%), while ADV showed a seroprevalence of 2.61%. PCV-2 was detected exclusively by molecular analysis in 66 out of 223 tested animals (29.6%). The overall objective of the study is to deepen the understanding of virus circulation in the wildlife of Southern Italy, using the wild boar as an additional sentinel species for epidemiological surveillance activities. The distinctive feature of the project lies in its multi-pathogen approach applied to a reference population distributed across a particularly wide geographical area, allowing for the simultaneous assessment of the circulation of different viruses over a large territory.

The circulation of viruses of medical and veterinary importance is monitored to evaluate risks to both human and animal health. Among the species most commonly used in surveillance programs, the wild boar (Sus scrofa) plays a key role due to its high popu-lation density and its contacts with rural swine herds in the areas under investigation. In this study, molecular and serological analyses were carried out on wild boar samples collected from the regions of Apulia, Basilicata, Campania, and Calabria. The aim of this study is assessing the circulation of Influenza viruses, porcine Circovirus type 2 (PCV-2), Flaviviruses, and Aujeszky’s disease virus (ADV). Molecular analyses confirmed the presence of Influenza virus and PCV-2 in the wild population, while serological moni-toring detected specific antibodies against Influenza viruses, Flaviviruses, and ADV. The overall objective of the study is to deepen the understanding of virus circulation in the wildlife of Southern Italy, using the wild boar as an additional sentinel species for epidemiological surveillance activities. The distinctive feature of the project lies in its multi-pathogen approach applied to a reference population distributed across a parti-cularly wide geographical area, allowing for the simultaneous assessment of the circu-lation of different viruses over a large territory.

Consumption of seafood, which includes both wild and aquaculture products, has increased several-fold during the last 50 years. Species substitution, in which low-value fish are replaced with high-value fish, is one of the prominent phenomena happening in the international seafood trade and the leading cause of fraud in the fishery sector, leading to both economic and health concerns. In this study, DNA barcoding was employed to identify 78 fishery product samples collected from markets and supermarkets located in the Apulia region (Southern Italy) at the genus or species level. Non-compliance between the species detected and the species declared in the label was detected in 5 (6.41%) samples. This study highlights the need for further investigations regarding the traceability and assessment of food product authentication. Indeed, accurate taxonomic assignment and a robust traceability system are essential tools for tackling food adulteration problems, providing transparency, and protecting food safety.

Salmonellosis is one of the most frequent foodborne zoonoses, and the consumption of contaminated poultry meat is considered the main source of Salmonella infections in humans. From 2021 to 2023, 384 chicken samples were collected from retailers in Apulia and Basilicata regions and analysed at the Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZSPB) laboratories. The Salmonella isolates were investigated to evaluate their phenotypic characteristics of antimicrobial resistance. A total of 125 (32.55%) samples tested positive for Salmonella spp. Three samples were simultaneously infected with strains of two different serotypes. Strains were classified into nine serotypes. Out of 128 strains, 112 (87.5%) isolates showed multidrug-resistant (MDR) profiles. Moreover, 16 isolates (12.5%) were ESBL producers with MDR profiles. Our data confirm that chicken products are a common source of Salmonella and highlight how S. Infantis was the most prevalent serotype (85.93%). Furthermore, Salmonella isolates showed antimicrobial resistance, which is very worrisome for animals and consumers. The high rate of antibiotic resistance along with the appearance of numerous MDR isolates is considered an actual concern and requires a robust surveillance network in a One Health concept.

Salmonella Infantis is one of the most frequent serovars reported in broilers and is also regularly identified in human salmonellosis cases, representing a relevant public health problem. In the laboratories of the Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZSPB), six Salmonella Infantis strains with antigenic formula -:r:1,5 have been isolated from the litter and carcass of broilers between 2018 and 2022. The strains were investigated to evaluate their phenotype, antibiotic resistance and genomic profiles. Genomic analysis confirmed that the isolates belonged to the Infantis serotype and to the sequence type ST32. Moreover, all strains showed a multidrug-resistant (MDR) profile and were characterised by the presence of the IncFIB plasmid incompatibility group. Three strains had the bla_CTX-M-1 gene, and one of them carried IncX1. The presence of this new variant of S. Infantis is particularly relevant because it could expand the landscape of the S. Infantis population. The absence of the somatic antigen could pose a problem in both isolation and serotyping and a consequent public health concern due to the spread of Salmonella infection.

The Bacillus cereus group includes species that act as food-borne pathogens causing diarrheal and emetic symptoms. They are widely distributed and can be found in various foods. In this study, out of 550 samples of milk and cheeses, 139 (25.3%) were found to be contaminated by B. cereus sensu lato (s.l.). One isolate per positive sample was characterized by Multilocus Sequence Typing (MLST) and for the presence of ten virulence genes. Based on MLST, all isolates were classified into 73 different sequence types (STs), of which 12 isolates were assigned to new STs. Virulence genes detection revealed that 90% and 61% of the isolates harboured the nheABC and the hblCDA gene cluster, respectively. Ninety-four percent of the isolates harboured the enterotoxin genes entS and entFM; 8% of the isolates possessed the ces gene. Thirty-eight different genetic profiles were identified, suggesting a high genetic diversity. Our study clearly shows the widespread diffusion of potentially toxigenic isolates of B. cereus s.l. in milk and cheeses in the Apulia region highlighting the need to adopt GMP and HACCP procedures along every step of the milk and cheese production chain in order to reduce the public health risk linked to the consumption of foods contaminated by B. cereus s.l.

The emergence of antimicrobial resistance (AMR) is increasingly common across the globe and aquatic ecosystems could be considered a reservoir of antibiotic-resistant bacteria. This study aimed to determine prevalence and antibiotic susceptibility of the potential pathogenic bacteria Salmonella spp. and Vibrio spp. in bivalve molluscs intended for human consumption, collected over a period of 19 months along the northern coast of Apulia region. The AMR profile was also determined in non-pathogenic Vibrio species, common natural inhabitants of seawater and a useful indicator for the surveillance of AMR in the environment. The current study presents data on the AMR of 5 Salmonella and 126 Vibrio isolates by broth microdilution MIC. Multidrug resistance (MDR) was observed in one S. Typhimurium strain towards sulfamethoxazole, trimethoprim, tetracycline, gentamicin, and ampicillin and in 41.3% of the Vibrio strains, mostly towards sulphonamides, penicillin, and cephems. All Vibrio isolates were sensitive to azithromycin, chloramphenicol, tetracycline, amoxicillin/clavulanic acid, gentamicin, streptomycin, amikacin, and levofloxacin. The AMR phenomenon in the investigated area is not highly worrying but not entirely negligible; therefore, in-depth continuous monitoring is suggested. Results concerning the antibiotic agents without available specific clinical breakpoints could be useful to upgrade the MIC distribution for Vibrio spp. but, also, the establishment of interpretative criteria for environmental species is necessary to obtain a more complete view of this issue.