Contamination by Staphylococcus aureus of food produced from animal sources may have diverse and multifactorial causes that depend on geographical distribution. The goal of this study was to isolate and characterise S. aureus strains from contaminated fermented pork sausage, which is a local food of northeastern Thailand. S. aureus strains were isolated from local pork sausage, and the presence of classical enterotoxins was determined by PCR and reversed passive latex agglutination. These results were compared with strains derived from hospitalised patients and healthy carriers. Additionally, production of extracellular enzymes and haemolysin, biofilm formation, and antibiotic susceptibility were assessed. S. aureus was identified in 36 sausage isolates (60%). The strains positive for staphylococcal enterotoxin A were more frequently found in isolates from sausage and healthy carriers than in those from patients. All tested S. aureus strains were positive for DNase, lipase, proteinase, haemolysin, and biofilm formation; notably, strains isolated from food and healthy carriers displayed similar values. Most isolates were resistant to penicillin and ampicillin, while none were to methicillin. Thai fermented pork sausages are associated with a high risk of staphylococcal food poisoning, which may be linked to contamination caused by carriers. Dissemination of knowledge regarding best practices in sanitation and hygiene is important in local communities.

In 2015 in the European Union member states listeriosis caused 270 deaths. Food is the route of transmission in 99% of all human infection cases. Several studies from different countries have shown that the presence of Listeria monocytogenes in food can be as high as 58.3%. One of the most important ways to protect food from these microorganisms is to prevent the spread of the bacteria at processing plants at different stages of food production chain. The ability of L. monocytogenes to survive in extreme conditions and to form biofilms on various surfaces is a significant challenge for food safety. Removal of these bacteria from niches in processing plants is difficult and requires the use of sanitisers and precise equipment cleaning. The presence of L. monocytogenes in processing environment at slaughterhouses, deli meat factories or in retail may be a reason of cross-contamination. Proper hygienic systems applied by workers in food preparing places and knowledge about different routes of spreading of these bacteria may effectively decrease the risk of food contamination. Standardised legal regulations and control of meat product manufacture should be a fundamental way to protect food from L. monocytogenes contamination.

The present investigation was undertaken to study the occurrence of enterotoxigenic B. cereus from 200 samples including 100 raw milk, 50pasteurized milk and 50 ice cream samples sold in Puducherry. The results revealed that 68 samples (34 %) belonged to B. cereus group which included 36 from raw milk (36%), 9 from pasteurized milk (18%) and 23 from ice cream samples (46 %). On PCR analysis, 64 out of 68 isolates showed the presence of gyrB gene which differentiates B. cereus from B. cereus group isolates. Multiplex PCR revealed the presence of four enterotoxigenic genes hblA, nheA, cytK and entF Min 32.35 %, 77.94 %>, 54.41 % and 94.12% of the 64 isolates. On biofilm production assay, out of 64 enterotoxigenic B. cereus isolates, 60 (93.75 %) isolates showed the ability to form biofilm in which 13 (20.31 %) were strong, 21 (32.81 %) were moderate and26 (40.63 %) were weak biofilm producers. All the isolates were resistant to ampicillin and penicillin G and sensitive to ciprofloxacin, gentamicin, vancomycin, streptomycin and norfloxacin. The current study directs the need for proper hygienic measures during collection, production, processing and storage of milk to reduce the contamination level. It also indicates the need for surveillance and action to reduce the contamination of enterotoxigenic B. cereus in milk and milk products in Puducherry.

The present study was aimed to investigate the presence of Escherichia coli (E.coli) in raw chicken meat samples collected from retail shops, as well as the biofilm-forming ability of field isolates, and to characterize different adhesion genes. Out of 20 chicken meat samples, 17 (85%) were positive for E. coli. Fifteen E. coli strains were characterized by PCR using the 16S rDNA primers and all the isolates were positive which confirmed that all the isolates were E.coli. Out of the 15 confirmed E.coli field isolates which were subjected to biofilm-forming assay, 46% of them were found to be strong biofilm producers. While all the isolates were screened for the presence of adhesion genes viz. luxS, csgA, fimH, fimA, and papC, the adhesion gene luxS was detected in all the strains (100%). The other adhesion genes csgA, fimH and fimA were detected in 93%, 93%, and 73% of the isolates, respectively. The E. coli field isolates were screened blaTEM gene was detected in only four strains, which was categorized under strong biofilm producers. This study demonstrated the presence of biofilm forming E. coli in the raw chicken meat samples as contaminants, causing spoilage and potentially posing risk to consumer’s health and safety.

This study was carried out on a total of 550 lactating animals; 310 and 240 cows and buffaloes, respectively which were examined for signs of clinical mastitis (swelling, hotness, redness, and apparent milk change) from different dairy farms and veterinary units located at El-Fayoum Governorate during the period from May 2017 to November 2017. Clinical examination proved that out of these animals, a total of 126 animals (87 cattle and 39 buffaloes) were found with clinical mastitis. Streptococcus species were recovered from 73 animals including; 29(39.7%) and 44(60.0%) cows and buffaloes, respectively. Furthermore, out of the 73 Streptococci isolates recovered from cows and buffaloes; there were 10(13.7%) and 15(20.5%) S. agalactiae, 5(6.8%) and 10(23.7%) S. dysgalactiae, 8 (10.6%) and 7 (13.7%) S. uberis, 3(4.1%) and 10(13.7 %) E. fecalis and 3(4.1%) and 2(2.7%) S. lactarius, respectively. Anti-microbial susceptibility testing showed that the highest resistance was recorded against penicillin, gentamicin, streptomycin, and doxycycline (100%). Conversely, the highest sensitivity was recorded against ceftriaxone, ciprofloxacin, and sulfamethoxazole-trimethoprim (100%). Biofilm formation capacity was phenotypically assessed on YESCA CR agar medium and showed that all examined S. agalactiae and S. dysgalactiae were strong biofilm producers, meanwhile, 78%, 50%, and 75% of S. uberis, S. lactarius, and E. fecalis were biofilm positive isolates respectively. Application of PCR technique revealed that enterotoxins producing genes; sed, seb were found in 20% and 80% of isolates, in order. Biofilm-associated genes; fnbA and icaA genes were detected in 90% and 70%, respectively. Resistance genes; mecA and blaZ, genes were possessed in 90% and 70% of isolates, respectively.

The objective of this study was to evaluate the bactericidal effect of shock waves (SWs) on gram-negative or gram-positive monocultured biofilms grown on an orthopedic implant in vitro. Cortical bone screws were individually cultured with Escherichia coli or Staphylococcus epidermidis to produce a biofilm. In each run of 8 screws, 6 screws were treated with shock waves and then sonicated to disrupt the biofilm. One screw was sonicated only and one was not shock waved or sonicated before sampling for plate count dilutions. Post-treatment serial dilutions and plate counts were done on an aliquot from the vial containing each screw to obtain the number of colony-forming units (CFUs). Shock waves were at a constant energy of 0.15 mJ/mm2. Pulse number and screw orientation were varied. A linear mixed-effects model was used with “treatment” as a fixed effect and “run” as a random effect. Pairwise comparisons of treatments were performed with Tukey-Cramer’s adjustment for P-values. Sonicated plate counts were greater than nonsonicated counts for each run. When all sonicated screws were compared to all nonsonicated screws, the counts were significantly increased (P = 0.0091). For each paired comparison between sonicated and shock wave treatment, the only significant difference was in the S. epidermidis biofilm treated at 2000 pulses in a horizontal position, which increased the post-treatment count (P = 0.0445). No bactericidal effects were seen on monocultured biofilms on cortical bone screws treated with shock waves.

Biofilm has been described as a barrier, which produced by microorganisms to survive and protect themselves against various environments, like antibiotic agents. Staphylococcus spp. is a common cause of nosocomial and environmental infection. Thirty-six and thirty-five Staphylococci were isolated from animals and air, respectively. Based on the biofilm forming ability of the bacterium reported in our previous report, relationship between biofilm formation and antibiotic-resistance was investigated in this study. Regarding antibiotics susceptibility, cefazolin was the most effective agent to the bacteria. Strong biofilm-forming Staphylococcus spp. isolates might have a higher antibiotic resistance than weak biofilm isolates regardless of the presence of antibiotic resistance genes (p less than 0.05). This result suggested that the chemical complexity of the biofilm might increase the antibiotic resistance due to the decrease of antibiotic diffusion into cells through the extensive matrix.

This study aimed to characterize the different Staphylococci recovered from mastitic cows and buffaloes. A total of 126 mastitis milk samples were aseptically collected from clinically mastitic animals including 87 cows and 39 buffaloes. Bacteriological examination and biochemical identification using VITEK-2-compact-SYSTEM revealed that a total of 94 Staphylococcus isolates (74.6%) were recovered; 56 isolates (59.6%) and 38 isolates (40%) from cows and buffaloes, respectively. S. aureus was the most predominant isolate (n=26; 15 from cows and 11 from buffaloes) with a percentage of 27.7%. Moreover, 68 coagulase-negative staphylococci (CNS) isolates (72.3%) were identified of which; 21 S. epidermidis (22.3%); all isolates were from cattle, followed by 18 S. lentus (19.1%); 8 and 10 from cows and buffaloes, respectively, 17 S. simulans (18%); 6 and 11 isolates, respectively, and finally 12 S. hominis (12.9%); 5 and 7 isolates, respectively. Antimicrobial susceptibility testing showed that all isolates were sensitive to ceftriaxone, ciprofloxacin, ofloxacin and sulfamethoxazole-trimethoprim. On the contrary, all isolates were resistant to penicillin and streptomycin. Multidrug resistance (MDR) was detected in 21 (22.3%) Staphylococci isolates. Biofilm formation capacity was phenotypically assessed on YESCA CR agar medium and showed that all Staphylococci isolates were curli-producing. Application of PCR technique revealed that sed, seb genes were the most prevalent genes in all isolates, followed by fnbA gene which was detected in 80% of the isolates, and then mecA, blaZ, and icaA with percentages of 60%, 40%, and 40%, respectively.

OBJECTIVE To evaluate the impact of gentamicin, silver, or both additives in polymethylmethacrylate (PMMA) beads on methicillin-resistant Staphylococcus pseudintermedius (MRSP) biofilm formation in vitro. SAMPLE 4 preparations of PMMA beads (formed with no additive [control], gentamicin, silver, and gentamicin and silver). PROCEDURES Beads from each group were exposed to 10 MRSP isolates known to be strong biofilm formers. Following incubation, the beads were rinsed to remove planktonic bacteria, then sonicated to dislodge biofilm-associated bacteria. Resulting suspensions were serially diluted, plated on blood agar, and incubated overnight; CFUs were counted. Variance of mean CFU counts following log10 transformation was analyzed among PMMA groups. RESULTS None of the PMMA additives tested completely inhibited MRSP biofilm formation. There was a significant effect of gentamicin and gentamicin plus silver on this variable, compared with controls, but not of silver alone. There was no difference between gentamicin and gentamicin plus silver. When only isolates not susceptible to gentamicin were evaluated, there were no significant differences among PMMA additive groups. Within gentamicin-susceptible isolates, there was an impact of gentamicin and gentamicin plus silver, but no impact of silver alone and no difference between gentamicin and gentamicin plus silver. CONCLUSIONS AND CLINICAL RELEVANCE Gentamicin-impregnated PMMA was effective at reducing biofilm formation of gentamicin-susceptible MRSP isolates but had no effect on isolates not susceptible to gentamicin. Silver-impregnated PMMA had no effect on MRSP biofilm formation. Results suggested that gentamicin-impregnated PMMA may not be effective in vivo against MRSP isolates not susceptible to gentamicin. Antibacterial efficacy of silver should not be assumed without proper testing of the target bacteria and specific silver compound.

Objective-To determine the prevalence of biofilm formation under long-term cell culture conditions in serum samples of dairy cattle, goats, cats, and dogs, and to determine whether there is an association between nanobacteria and biofilm formation. Sample Population-Serum samples of clinically normal animals (313 dairy cattle, 48 goats, 140 dogs, and 44 cats) and animals with various medical conditions (60 dogs and 116 cats). Procedure-Serum was incubated under cell culture conditions and observed for biofilm formation by use of light microscopy, electron microscopy, and spectroscopy. A polymerase chain reaction assay was developed to identify 16S rRNA gene sequences of nanobacteria. Results-Biofilm formation developed in serum samples of 304 of 313 (97%) cattle, 44 of 48 (92%) goats, 44 of 44 (100%) cats, and 126 of 140 (90%) dogs. Prevalence of serum samples with positive results for biofilm formation was not significantly different between cats or dogs with and without medical conditions associated with pathologic extraskeletal calcification processes. Scanning electron microscopy and spectroscopy of biofilm samples revealed small coccoid particles consisting mainly of calcium and phosphate. Polymerase chain reaction assay failed to amplify sequences of nanobacteria. Conclusions and Clinical Relevance-Under longterm cell culture conditions, biofilm made up of aggregates of calcium and phosphate crystals does form in serum samples of clinically normal dairy cattle, goats, cats, and dogs. Disease, however, does not predispose to biofilm formation in serum samples of dogs and cats. Our findings did not support the existence of nanobacteria in serum samples of cattle, goats, cats, and dogs.