Bacillus cereus in the Artisanal Cheese Production Chain in Southwestern Mexico.

BACKGROUND: Bacillus cereus is associated with milk, dairy product, and dairy farm contamination. The aim of this study was to characterize strains of B. cereus in the small-scale artisanal cheese production chain in southwestern Mexico. METHODS: 130 samples were collected. B. cereus isolation was performed on Mannitol Egg Yolk Polymyxin (MYP) agar. Genotyping, enterotoxigenic profile, and determination of genes involved in the formation of B. cereus biofilm were performed by PCR. An antimicrobial susceptibility test was made by broth microdilution assay. The phylogenetic analysis was performed by amplification and sequencing of 16s rRNA. RESULTS: B. cereus sensu lato was isolated and molecularly identified in 16 samples and B. cereus sensu stricto (B. cereus) was the most frequently isolated and identified species (81.25%). Of all the isolated B. cereus sensu lato strains, 93.75% presented at least one gene for some diarrheagenic toxins, 87.5% formed biofilms, and 18.75% were amylolytic. All B. cereus sensu lato strains were resistant to beta-lactams and folate inhibitors. A close phylogenetic relationship between isolates was found between the cheese isolates and the air isolates. CONCLUSIONS: Strains of B. cereus sensu lato were found in small-scale artisanal cheeses on a farm in southwestern Mexico.

PADI4 Haplotypes Contribute to mRNA Expression, the Enzymatic Activity of Peptidyl Arginine Deaminase and Rheumatoid Arthritis Risk in Patients from Western Mexico.

Citrullination is catalyzed by the peptidyl arginine deiminase 4 (PAD4) enzyme, encoded by the PADI4 gene. Increased PAD4 activity promotes the onset and progression of rheumatoid arthritis (RA). This study aimed to evaluate the association of PADI4 haplotypes with RA risk, mRNA expression, and the PAD4 activity in patients with RA from Mexico. Methodology: 100 RA patients and 100 control subjects (CS) were included. Genotyping was performed by PCR-RFLP method, PADI4 mRNA expression was quantified by real-time PCR, the contribution of PADI4 alleles (PADI4_89 G>A, PADI4_90 T>C, and PADI4_92 G>C) to mRNA expression by the ASTQ method, and PAD4 activity by HPLC. Also, the anti-CCP and anti-PADI4 antibodies were quantified by ELISA. Results: The three PADI4 polymorphisms were associated with RA susceptibility (OR = 1.72, p = 0.005; OR = 1.62; p = 0.014; OR = 1.69; p = 0.009; respectively). The 89G, 90T, and 92G alleles have a higher relative contribution to PADI4 mRNA expression from RA patients than 89A, 90C, and 92C alleles in RA patients. Moreover, the GTG/GTG haplotype was associated with RA susceptibility (OR = 2.86; p = 0.024). The GTG haplotype was associated with higher PADI4 mRNA expression (p = 0.04) and higher PAD4 enzymatic activity (p = 0.007) in RA patients. Conclusions: The evaluated polymorphisms contribute to PADI4 mRNA expression and the enzymatic activity of PAD4 in leukocytes. Therefore, the GTG haplotype is a genetic risk factor for RA in western Mexico, and is associated with increased PADI4 mRNA expression and higher PAD4 activity in these patients.

Prevalence of the Strains of Bacillus cereus Group in Artisanal Mexican Cheese.

Bacillus cereus is a microorganism associated with food poisoning. It has been found in products, such as milk and dairy products. The aim of this study was to isolate and identify B. cereus group strains in artisan cheeses sold in southwestern Mexico, as well as its toxigenic profile, its psychrophilic ability, and its biofilm production. B. cereus isolation was performed on Mannitol Yolk Polymyxin (MYP) agar and this was molecularly confirmed by the amplification of the gyrB gene. Polymerase chain reaction was used to determine the toxigenic profile, amplifying conserved regions of hblABD and nheABC operons, which code for the subunits of Hbl and Nhe toxins, respectively, as well as ges and cytK genes, which code for toxin cereulide and cytotoxin K (Cytk). Frequency of B. cereus contamination in artisan cheeses was 29.48% (23/78), and the bacterium was isolated in similar quantities in all types of products. All strains were amylase positive, and 60.86% (14/23) were able to produce biofilm; 91.30% (21/23) of the strains were psychrophilic. In most of the strains, at least one gene related to enterotoxins was identified (21/23). B. cereus strains in this study have a high toxigenic potential, which increases the risk of food poisoning due to the consumption of artisan cheeses made in Mexico.

Staphylococcus aureus resistentes a meticilina (SARM) y productores de enterotoxina A aislados de portadores nasales asintomáticos entre estudiantes universitarios de México / Methicillin resistant Staphylococcus aureus (MRSA) and enterotoxin A producer isolated from asymptomatic nasal carriage among undergraduate students of Mexico

El objetivo de este estudio fue determinar la frecuencia de S. aureus, incluyendo resistentes a meticilina y la producción de enterotoxina A en fosas nasales de estudiantes universitarios en México. Este fue un estudio transversal realizado en 471 estudiantes universitarios de una ciudad del suroeste de México. Las muestras nasales y los datos sociodemográficos fueron obtenidos de los pacientes. Las cepas fueron identificadas como S. aureus basándose en la morfología, tinción de Gram, prueba de catalasa, prueba de coagulasa y fermentación en agar manitol salado. Las cepas se biotipificaron, se determinó la resistencia a meticilina por difusión en agar y la producción de enterotoxina A por Dot- Blot. La frecuencia de portadores nasales de S. aureus fue 10,40 %; 73,46 % resistentes a meticilina; 36,73 % producen enterotoxina A. En un análisis bivariado, se encontraron diferencias estadísticamente significativas en pacientes que viven cerca de aguas residuales y granjas con el estado de portador de S. aureus, (p=0,01, OR 2,59 [1,06-5,81]; p=0,01, OR 3,18, [1,07- 8,33]). Los portadores nasales muestran una diversidad de cepas de S. aureus, mayormente resistentes a meticilina, pero no todas producen enterotoxina A.

The aim at this study was determine the frequency of S. aureus, including methicillin-resistant and enterotoxin A production in nostrils of university students in Mexico. This was a cross-sectional study conducted in 471 university students from a city in southwestern Mexico. Nasal samples and sociodemographic data were obtained from the patients. Strains were identified as S. aureus based on morphology, Gram stain, catalase test, coagulase test and fermentation on salted mannitol agar. Isolated strains were subjected to biotyping, their methicillin resistance was analyzed using the agar diffusion method and examined their enterotoxin A (SEA) production by a Dot-blot analysis. The nasal carriage rate of S. aureus was 10.40%; 73.46% of the isolates were resistant to methicillin; 36.73% of the strains produced enterotoxin A. In the bivariate analysis, a statistically significant difference was found in patients who lived near sewage and farms with S. aureus carriage (p=0.012, odds ratio 2.59, [ 1.06-5.81]; p=0.009, odds ratio 3.18, [1.07- 8.33]) and the first group also associated with methicillin resistant S. aureus carriage (p=0.020, odds ratio 3.38, [1.30-8.06]). Nasal carriers show a wide variety of strains of S. aureus, mostly MRSA strains, but not all produce enterotoxin A.

Influence of serum leptin levels and Q223R leptin receptor polymorphism on clinical characteristic of patients with rheumatoid arthritis from Western Mexico.

OBJECTIVE: The aim of the present study was to evaluate the possible association between the Q223R Leptin receptor (LEPR) polymorphism (A>G; rs1137101) and leptin levels in patients with rheumatoid arthritis (RA) from Western Mexico. METHODS: A cross-sectional study was performed with 70 RA patients and 74 controls subject (CS). Disease activity was evaluated using DAS28 score, the Q223R LEPR polymorphism was determined by the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and serum leptin levels, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and rheumatoid factor (RF) were quantified. RESULTS: RA patients had significant high serum leptin levels compared with CS; leptin levels correlated strongly with body composition measures, but not with inflammatory markers, disease evolution, and activity. The genotype and allele frequencies of the Q223R LEPR polymorphism were not associated with RA. Similarly, leptin levels did not differ between Q223R LEPR genotypes. CONCLUSION: The LEPR Q223R polymorphism was not associated with RA risk in patients from Mexican population, even though high levels of serum leptin were present and these could explain the low weight observed in RA patients when they were compared to control subjects. However, the serum leptin levels did not correlate with inflammatory markers, severity and disease evolution.

Polymorphisms and functional haplotype in PADI4: further evidence for contribution on rheumatoid arthritis susceptibility and anti-cyclic citrullinated peptide antibodies in a western Mexican population.

Peptidyl arginine deiminase IV (PADI4) enzyme catalyzes the citrullination of proteins, which are recognized by anti-cyclic citrullinated peptide antibodies (anti-CCP) in rheumatoid arthritis (RA) patients. Here, we determined the association between PADI4 gene polymorphisms and haplotypes with RA susceptibility and clinical characteristics in a western Mexican population. The relationship of PADI4 polymorphisms with anti-CCP and PADI4 mRNA expression was also evaluated. PADI4_89, PADI4_90 and PADI4_92 polymorphisms were individually associated with RA susceptibility. The GTG haplotype was significantly associated with: RA susceptibility; disease onset at ≤ 40 years and anti-CCP antibodies. PADI4 expression was three fold higher in RA patients carrying the susceptibility haplotype (GTG) than in non-susceptibility haplotype carriers (ACC). In conclusion, polymorphisms and functional haplotype (GTG) in PADI4 are associated with RA susceptibility as well as anti-CCP antibodies in a Mexican population. This supports the role of PADI4 early in RA pathogenesis by promoting the generation of citrullinated autoantigens.

The extrapituitary prolactin promoter polymorphism is associated with rheumatoid arthritis and anti-CCP antibodies in Mexican population.

Prolactin (PRL) is a hormone-cytokine that has been involved in autoimmunity due to its immunoregulatory and lymphoproliferative effects. It is produced by various extrapituitary sites including immune cells, under control of a superdistal promoter that contains a single nucleotide polymorphism -1149 G/T previously associated with rheumatoid arthritis (RA) susceptibility in European population. The aim of this study was to investigate the association of the extrapituitary PRL -1149 G/T promoter polymorphism with clinical parameters, clinical activity and disability indices in RA patients from Western Mexico and to analyze the PRL mRNA expression according to the PRL -1149 G/T promoter polymorphism in total leucocytes from RA patients and controls. We conducted a case-control study that included 258 RA patients and 333 control subjects (CS). The DNA samples were genotyped using the PCR-RFLP method and the PRL mRNA expression was determined by quantitative real time PCR. PRL serum levels and antibodies to cyclic citrullinated peptides (anti-CCP) were measured with ELISA. We found significant differences in the genotype (p=0.022) and allelic (p=0.046) distribution of the polymorphism between RA patients and control subjects. According to the dominant genetic model, there is an association between the T allele (GT+TT genotypes) and decreased RA susceptibility in comparison to the G allele carriers (GG genotype) (OR 0.64, 95% CI 0.45-0.92; p=0.011). The T allele carriers (GT+TT genotypes) had lower titers of anti-CCP antibodies in comparison to the G allele carriers (GG genotype) (median, 66 U/mL vs. 125 U/mL; p=0.03). Furthermore, the GG homozygotes had higher PRL mRNA expression in comparison to the GT heterozygotes, and this latter with respect to the TT homozygotes, in both groups (RA: 1>0.72>0.19; CS: 1>0.54>0.28). However, PRL serum levels were similar in both groups. Our results suggest that the PRL -1149 T allele is a genetic marker for decreased RA susceptibility and is associated with lower titers of anti-CCP antibodies in Mexican population. We also suggest influence of genotype upon PRL mRNA expression.

Association of the HindIII and S447X polymorphisms in LPL gene with hypertension and type 2 diabetes in Mexican families.

Lipoprotein lipase (LPL) is a key enzyme in lipid metabolism and is associated with obesity, dyslipidemias, hypertension (HTN) and type 2 diabetes mellitus (T2DM). LPL gene polymorphisms can be related with the development of cardiovascular risk factors. The present study was conducted to analyze the relationship of the HindIII and S447X polymorphisms in LPL gene with cardiovascular risk factors in Mexican families. The study population comprised ninety members of 30 Mexican families, in which an index case had obesity, were included in the study. We evaluated the body composition by bioelectrical impedance. Peripheral blood samples were collected to determine biochemical parameters. Screening for both polymorphisms was made by PCR-RFLPs. In the parents, both polymorphisms were in Hardy-Weinberg's equilibrium. We found that the genotype T/T of HindIII was associated with diastolic blood pressure ≥ 85 mmHg (OR=1.1; p=0.011), whereas the genotype C/C of S447X was associated with systolic blood pressure ≥ 130 mmHg (OR=1.2; p<0.001), diastolic blood pressure ≥ 85 mmHg (OR = 1.3; p< 0.001), T2DM (OR=1.3; p< 0.001) and with increase of total cholesterol (ß =23.6 mg/mL; p=0.03). These data suggest that the HindIII and S447X LPL gene polymorphisms can confer susceptibility for the development of hypertension and T2DM in Mexican families.