Staphylococcus aureus is an important food-borne pathogen able to form biofilms. This pathogen is responsible for outbreaks of food-borne illnesses associated with the consumption of milk and dairy products. The aim of this study was to evaluate the biofilm-forming ability of S. aureus isolates, recovered from food contact surfaces in the dairy industry of Jalisco, Mexico. A total of 84 S. aureus strains were evaluated. The isolates were characterized phenotypically by culture on Congo red agar plates. The ability of the strains to form biofilms was investigated in 96-well flat-bottomed microtiter polystyrene plates. Stainless-steel coupons were used as an experimental surface. Biofilm formation was observed, using epifluorescence microscopy and scanning electron microscopy. Detection of the icaADBC genes in S. aureus was performed by the PCR technique. A total of 52.3% (44/84) of the S. aureus strains contained the icaADBC gene that synthesizes polysaccharide intercellular adhesion (PIA) molecules. On Congo red agar, 75% (63/84) of the S. aureus isolates were biofilm producers, 16.6% (14/84) were non-biofilm formers, and 8.3% (7/84) showed a noncharacteristic phenotype. The biofilm production of the S. aureus strains SA-4E, SA-9, SA-13, and SA-19 on stainless-steel coupons was investigated at 25°C for 8 days, and the detected cell population density was approximately 7.15–7.82 log CFU cm⁻². In addition to the ability of biofilm production, it is important to highlight that these strains are potential enterotoxin producers as se genes have been previously detected in their genomes. A part of the ability of biofilm production and the determination of the presence of virulence determinants in the genome of S. aureus can contribute to the pathogenicity of strains. Therefore, vigilant food safety practices need to be implemented in the dairy industries regarding FCS to prevent food-borne infections and intoxications due to S. aureus contamination.

Acinetobacter baumanniiis an important opportunistic pathogen that shows resistance to cephalosporins, penicillins, carbapenems, fluoroquinolones, and aminoglycosides, the multiresistance being associated with its ability to form biofilms in clinical environments. The aim of this study was to determine biofilm formation and its potential association with genes involved in antibiotic resistance mechanisms ofA. baumanniiisolates of different clinical specimens. We demonstrated 100% of theA. baumanniiisolates examined to be multidrug resistant (MDR), presenting a 73.3% susceptibility to cefepime and a 53.3% susceptibility to ciprofloxacin. AllA. baumanniiisolates were positive forbla_OXA-51, 33.3% being positive forbla_OXA-23and ISAba1, and 73.3% being positive forgyrA. We found 86.6% ofA. baumanniistrains to be low-grade biofilm formers and 13.3% to be biofilm negative; culturing on Congo red agar (CRA) plates revealed that 73.3% of theA. baumanniiisolates to be biofilm producers, while 26.6% were not. These properties, combined with the role ofA. baumanniias a nosocomial pathogen, increase the probability ofA. baumanniicausing nosocomial infections and outbreaks as a complication during therapeutic treatments and emphasize the need to controlA. baumanniibiofilms in hospital environments.

Staphylococcus aureus is widely distributed in nature, and two of the main sources of S. aureus contamination in the food industry are food handlers and Food Contact Surfaces (FCS). This pathogen is responsible for outbreaks of foodborne illnesses associated with the consumption of milk and dairy products. The aim of this study was to determine the prevalence of toxin-encoding genes in S. aureus isolates from FCS in the Jalisco dairy industry. The presence of enterotoxin genes was investigated by PCR. In this study, we identify 84 S. aureus isolates. Overall, 35.7% of the isolates tested positive for at least one of the nine studied enterotoxin genes, and 15.4% harbored 2-4 enterotoxin genes. The most predominant genes were sej and sed. This study demonstrates that FCS are a source of contamination for this food rotation and that there is a diversity of enterotoxin genes in S. aureus isolates. Therefore, vigilant food safety practices need to be implemented regarding FCS to prevent foodborne infections and intoxications due to S. aureus contamination.

• Phages M3, C2, M9, and M83 belong to a new species of the genus of Maculvirus and phages ALK and CHI belong to new genus of the Queuovirinae subfamily. • CHI, ALK, M3, C2, M9, and M83 could lyse 50.0% (5/10) of Mexican AHPND-causing Vibrio parahaemolyticus strains. • No transfer RNA (tRNA), virulence, or antibiotic resistance genes were found in phage genomes. • CHI, ALK, M3, C2, M9, and M83 significantly reduced the growth of Mexican AHPND-causing Vibrio parahaemolyticus strains after incubating with MOI of 0.01–1.