Detection of carbapenemase- and ESBL-producing Klebsiella pneumoniae from bovine bulk milk and comparison with clinical human isolates in Italy.

Klebsiella pneumoniae is the most common Klebsiella species infecting animals and is one of the causing agents of mastitis in cows. The rise of antimicrobial resistance in K. pneumoniae, particularly in strains producing extended-spectrum ß-lactamases (ESBLs) and/or carbapenemases, is of concern worldwide. Recently (Regulation UE No 2022/1255), carbapenems and cephalosporins in combination with ß-lactamase inhibitors have been reserved only to human treatments in the European Union. The aim of this study was to investigate the role of cattle as carrier of human pathogenic carbapenem-resistant (CR) and ESBL-producing K. pneumoniae. On this purpose, a study involving 150 dairy farms in Parma province (Northern Italy) and 14 non replicate K. pneumoniae isolates from patients admitted at Parma University-Hospital was planned. Four multidrug resistant (MDR) K. pneumoniae strains were detected from 258 milk filters collected between 2019 and 2021. One carbapenemase KPC-3-positive K. pneumoniae ST307 (0.4 %; 95 % CI - 0.07 - 2.2) was detected in milk filters. The isolate also harboured OXA-9, CTX-M-15 and SHV-106 determinants, together with genes conferring resistance to aminoglycosides (aac(3')-IIa, aph (3″)-Ib, aph (6)-Id), fluoroquinolones (oqxA, oqxB, qnrB1), phosphonic acids (fosA6), sulphonamides (sul2), tetracyclines (tet(A)6) and trimethoprim (dfrA14). One KPC-3-producing K. pneumoniae ST307 was identified also among the human isolates, thus suggesting a possible circulation of pathogens out of the clinical settings. The remaining three bovine isolates were MDR ESBL-producing K. pneumoniae characterized by different genomic profiles: CTX-M-15, TEM-1B and SHV-187 genes (ST513); CTX-M-15 and SHV-145 (ST307); SHV-187 and DHA-1 (ST307). Occurrence of ESBL-producing K. pneumoniae in milk filters was 1.2 % (95 % CI 0.4-3.4). All the isolates showed resistance to aminoglycosides, 3rd-generation cephalosporins, and fluoroquinolones. Among the human isolates, two multidrug resistant ESBL-producing K. pneumoniae ST307 were found, thus confirming the circulation of this high-risk lineage between humans and cattle. Our findings suggest that food-producing animals can carry human pathogenic microorganisms harboring resistance genes against carbapenems and 3rd-generation cephalosporins, even if not treated with such antimicrobials. Moreover, on the MDR K. pneumoniae farms, the antimicrobial use was much higher than the Italian median value, thus highlighting the importance of a more prudent use of antibiotics in animal productions.

Antimicrobial resistance pattern of methicillin-resistant Staphylococcus aureus in the food industry.

There is increasing concern about the impact on public health of methicillin-resistant Staphylococcus aureus (MRSA) associated with animal food products. MRSA remains a serious problem because of the high incidence and multidrug resistance of the strains, even for strains isolated from foods, food environments and food handlers. The objectives of this study are: (i) to evaluate the susceptibility of S. aureus strains isolated from food, food handlers and food-processing environments to 14 antibiotics currently used in veterinary and human therapy; (ii) to assess the presence of the mecA gene. A total of 1007 samples were collected from food, food handlers, and environments and were analyzed for the presence of S. aureus. S. aureus was present in 165 of the 1007 samples. A total of 157 isolates were methicillin-susceptible S. aureus (MSSA) and 8 isolates were MRSA. In particular, out of 8 MRSA strains detected, 4 strains harboured the mecA gene. All MRSA strains were resistant to at least one of the tested antibiotics and 6 strains demonstrated multi-resistance. Considering the high level of resistances in S. aureus and the isolation of MRSA strains, the surveillance of antimicrobial resistance and the spreading of this pathogen is of crucial importance in the food production chain. These data are useful in improving background data on antimicrobial resistance of S. aureus isolated from food, processing environments and food handlers, supporting the prudent use of antibiotics and the development of international control programs.

The challenge of education for the veterinary inspector.

The aim of this review is to provide an insight into the current state of, and future changes in, veterinary education. At present, Veterinary Inspectors need to have the appropriate education, relevant experience and the ability to carry out their duties in the context of inspections. They should respond to the changes in legislation related to food and to the official control systems and must take into account the Community rules. In effect, there is still a wide diversity among schools in Italy and in Europe, showing that there is an urgent need for harmonization of the veterinary education, in order to have a common basis of knowledge. Moreover, it is important to maintain and update all knowledge by means of the so-called lifelong learning. Along the educational route of the veterinary inspector, many gaps still exist: the entire system of learning should be revised, with the aim of having a well-integrated education system in cooperation with all the figures involved. In this way Veterinary Inspectors will be able to face the new issues posed by society and the globalization of food consumption and will be able to maintain their position in the assurance of food safety.

Influence of temperature on biofilm formation by Listeria monocytogenes on various food-contact surfaces: relationship with motility and cell surface hydrophobicity.

AIMS: To assess the ability of Listeria monocytogenes to form biofilm on different food-contact surfaces with regard to different temperatures, cellular hydrophobicity and motility. METHODS AND RESULTS: Forty-four L. monocytogenes strains from food and food environment were tested for biofilm formation by crystal violet staining. Biofilm levels were significantly higher on glass at 4, 12 and 22 degrees C, as compared with polystyrene and stainless steel. At 37 degrees C, L. monocytogenes produced biofilm at significantly higher levels on glass and stainless steel, as compared with polystyrene. Hydrophobicity was significantly (P < 0.05) higher at 37 degrees C than at 4, 12 and 22 degrees C. Thirty (68.2%) of 44 strains tested showed swimming at 22 degrees C and 4 (9.1%) of those were also motile at 12 degrees C. No correlation was observed between swimming and biofilm production. CONCLUSIONS: L. monocytogenes can adhere to and form biofilms on food-processing surfaces. Biofilm formation is significantly influenced by temperature, probably modifying cell surface hydrophobicity. SIGNIFICANCE AND IMPACTS OF THE STUDY: Biofilm formation creates major problems in the food industry because it may represent an important source of food contamination. Our results are therefore important in finding ways to prevent contamination because they contribute to a better understanding on how L. monocytogenes can establish biofilms in food industry and therefore survive in the processing environment.