Phenotypic and Genotypic Characterization of Methicillin, Vancomycin, and Erythromycin-resistant Staphylococcus aureus Isolated from Milk and Dairy Products

Detailed information on the resistance patterns of Staphylococcus aureus (S. aureus) in milk and cheese is strongly required to facilitate risk assessment analysis in case of food poisoning context and to improve therapeutic approaches used in dairy farms. The present study aimed to perform phenotypic and genotypic antimicrobial characterizations of methicillin, vancomycin, and erythromycin-resistant S. aureus isolated from milk and dairy products through screening mecA, vanA, and ermC using molecular PCR amplification technology. Moreover, the association between each genotypic and its related antibiotic resistance phenotypic features within the isolated S. aureus strains were analyzed. Moreover, the current study aimed to study MRSA's ability to form biofilms. Out of 226 milk and dairy product samples collected from different retailers in Giza Governorate, 69.5% of the samples were positive for the presence of S. aureus. The isolation rate of S. aureus strains from cattle milk, sheep milk, white cheese, flamenco, and mesh samples were 79.7%, 76.5%, 56.0%, 40.0%, and 94.7%, respectively. Multidrug-resistant S. aureus (MDR) was detected in 51% of all isolated S. aureus strains. All tested S. aureus strains were sensitive to trimethoprim-sulfamethoxazole, linezolid, ciprofloxacin, and gentamycin. However, their resistance rates against penicillin, oxacillin, vancomycin, erythromycin, tetracycline, clindamycin and chloramphenicol were 62.4%, 65.0%, 44.6%, 45.9%, 21.0%, 14.0%, and 2.5%, respectively. Of the isolated S. aureus strains, 72.6%, 40.1%, and 48.4% were carriers for mecA, vanA, and ermC genes and the amplified products were at 310, 1030, and 295 bp, respectively. Methicillin-resistant S. aureus isolates were detected in 47.1% of all isolated S. aureus strains. The results indicated that 35.0% of the tested S. aureus strains were genotypic vanA gene carriers and phenotypic resistant to vancomycin representing vancomycin-resistant S. aureus strains. Moreover, 42.7% of all isolated S. aureus strains were carriers for ermC gene and were phenotypic resistant to erythromycin representing erythromycin-resistant S. aureus. The presence of mecA, vanA, and ermC genes in S. aureus was statistically associated with their related phenotypic resistance patterns against both penicillin and oxacillin, vancomycin, and erythromycin, respectively. Moreover, along with an increase in the frequency of mecA, vanA, and ermC genes, their phenotypic antibiotic resistance patterns sharply increased with an odd ratio >1. Of MRSA isolates, 6.8% indicated weak biofilm-formation ability, while 93.2% exhibit no biofilm-forming ability.

الأنماط الاستهلاكية للألبان و منتجاتها في ولاية الخرطوم

الأنماط الاستهلاكية للألبان و منتجاتها في ولاية الخرطوم This research aimed at identifying the different consumption trends of the Sudanese individual in regard to fresh milk and dairy products. It also aimed at making use of studying the behavioral consumption in the marketing field and to set a future prospectus to accomplish development and quality in dairy marketing in Sudan. To achieve such aims a number of hypothesis were tested through analysis of data collected from families in Khartoum state different statistical methods were implemented. Several results were concluded, of which are: 1 .Fresh milk has high acceptance among Sudanese consumers. 2. The consumer has low trust in the quality of fresh milk sold by roaming sellers. 3. The Sudanese consumer has low nutritional and health awareness about the value of dairy products (other than white cheese & yogurt). The study was concluded with several recommendations, of which are: 1. Adapting modem marketing concepts by giving more attention to consumer needs and demands and benefiting from Sudanese consumers' general food culture in the marketing procedure. 2 . Performing marketing research on consumption patterns and habits of the Sudanese individual to benefit out of them in dairy marketing

Prevalence and Characterization of Antibiotic-Resistant Staphylococcus aureus Recovered from Pasteurized Cheese Commercialized in Panama City Markets

Foodborne bacteria, with a high degree of antibiotic resistance, play an important role in the morbidity and mortality of gastrointestinal diseases worldwide. Among 250 disease-causing bacteria, Staphylococcus aureus is one of the major causes of food poisoning, and its resistance to multiple antimicrobials remains of crucial concern. Cheese is often contaminated when proper sanitary procedures are not followed during its production and marketing. This work aimed to evaluate the microbiological quality of pasteurized white cheese commercialized in Panama City. Cheese from five different brands sold in local supermarkets were selected to determine the presence of S. aureus as well as its antibiotic resistance profile. The results showed significant contamination of S. aureus with a geometric median sample of 104–107 CFU/g. Four out of five (4/5) cheese brands analyzed presented risk of food poisoning by exceeding the allowed range of consumption with a geometric median sample of 1,8 × 106–1,4 × 107 CFU/g. Fourteen different resistance phenotypes were found. Fifty-five percent (55%) of the analyzed strains were resistant to erythromycin. The data confirm a relatively high prevalence and high levels of S. aureus, most likely originated during handling in Panama City retail markets. Further studies are needed to reduce bacterial contamination and to decrease the risk of food poisoning in the consumption of pasteurized cheese.

Comparative study of antibiofilm activity of Lime juice and Lithium dioxide nanoparticles against E.coli isolated from local made cheese

Thirty specimens of fresh white cheese, in different markets at different cities of Iraq were analyzed microbiologically. Isolates of E.coli that have been collected from the samples of cheese, were investigated. Capacity for biofilm producing was demonstrated by two method, Tissue culture plate method (TCP) and agar (CRA). After that, antibiofilm activity of lime extract and LiO2NPs was studied as each one of them alone and then the synergistic effect was done by TCP method. The results showed that all E.coli isolates produce biofilm but in different degrees. The results also displayed that Lime extract and LiO2NPs had antibiofilm effect against E.coli when used alone and when the combination done between each one of these materials. In conclusion, it was observed that the specimens of fresh white cheese included in this study contained microbial contamination at a health-threatening level but elimination of this contamination can be done by using lime extract and LiO2NPs.

Prevalence and Genetic Diversity of Coagulase Negative Staphylococcus in Food Products Collected from Riyadh Region

The goal of this study was to isolate, count, and identify coagulase-negative Staphylococci from meat and dairy products collected in Riyadh, Saudi Arabia, as well as to perform molecular identification of the mecA gene. In addition, the prevalence of these bacteria among the examined food products was determined. Ninety samples of both meat and dairy products were collected and examined between February 2018 and August 2019. Mannitol salt agar and VITEK 2 system were carried out and VITEK 2 system was used to identify all bacterial isolates. Also, the molecular technique was used to detect the target gene of mecA among CoNS. The proportion of samples in which Staphylococcus species isolated is 13.33% (Camel meat), 6.66% (Beef mortadella), 6.66% (Turkish labneh), 33.33% (Cows cheese), 6.66% (Goat labneh), 13.33% (Nabulsy cheese), 13.33% (Haloumi goat cheese) and 6.66% (Akawy white cheese). Counts of coagulase-negative Staphylococcus species (as cfu/gm) of sample were around 11×104, 10×104, 9×104, 12×104, 4×105, 11×104 (Nabulsy cheese), 14×104 and 12×104, respectively. The Prevalence of species in both products was 3.30% (Staphylococcus vitulinus), 53.30% (Staphylococcus saprophyticus), 16.66% (Staphylococcus hominis), 6.66%, (Staphylococcus equorum and Staphylococcus lentus) and 13.33% (Staphylococcus sciuri). Furthermore, results showed methicillin specific mecA gene was harbored in 40 % of the CoNS.