Detection of Oxacillin/Cefoxitin Resistance in Staphylococcus aureus Present in Recurrent Tonsillitis.

BACKGROUND: Recurrent tonsillitis is one of the most common diseases in childhood, caused many times by ß-lactam-resistant S. aureus. The objective of this study was to investigate an alternative method to identify resistance to oxacillin/cefoxitin in S. aureus from hospitalized children with recurrent tonsillitis. METHODS: The samples of S. aureus came from patients with recurrent tonsillitis and were used in 16S rRNA sequencing and an antibiogram test for identification and verifying resistance, after which HSI methodology were applied for separation of S. aureus resistances. RESULTS: The S. aureus isolated showed sensitivity to oxacillin/cefoxitin and the diagnostic images show a visual description of the resistance different groups formed, that may be related to sensitivity and resistance to oxacillin/cefoxitin, characterizing the MRSA S. aureus. CONCLUSIONS: Samples that showed phenotypic resistance to oxacillin/cefoxitin were clearly separated from samples that did not show this resistance. A PLS-DA model predicted the presence of resistance to oxacillin/cefoxitin in S. aureus samples and it was possible to observe the pixels classified as MRSA. The HSI was able to successfully discriminate samples in replicas that were sensitive and resistant, based on the calibration model it received.

Escherichia coli, Species C Human Adenovirus, and Enterovirus in Water Samples Consumed in Rural Areas of Goiás, Brazil.

Rural environments lack basic sanitation services. Facilities for obtaining water and disposing sewage are often under the initiative of each resident, who may not be able to build and maintain them properly. Thus, water for human consumption is subject to fecal contamination and, consequently, the presence of waterborne pathogens, such as enteric viruses. This study evaluated fecal contamination of water samples from individual sources used for domestic water supply on small farms in the state of Goiás, Brazil. Samples were collected from 78 houses whose water sources were tubular wells, dug wells, springs, and surface waters. Escherichia coli (EC) bacteria, analyzed by the defined chromogenic substrate method, was used as a traditional indicator of fecal contamination. The enteric viruses Human mastadenovirus (HAdV) and Enterovirus (EV), analyzed by qPCR, were tested as complementary indicators of fecal contamination. At least one of these markers was found in 89.7% of the samples. Detection rates were 79.5% for EC, 52.6% for HAdV, and 5.1% for EV. The average concentration for EC was 8.82 × 101 most probable number (MPN) per 100 mL, while for HAdV and EV the concentrations were 7.51 × 105 and 1.89 × 106 genomic copies (GC) per liter, respectively. EC was the most frequent marker in ground and surface water samples. HAdV was detected significantly more frequently in groundwater than in surface water and was more efficient in indicating contamination in tubular wells. There was no association of frequencies or correlation of concentrations between EC and HAdV. HAdV indicated human fecal contamination and performed well as a complementary indicator. The results reveal that a large part of the analyzed population is vulnerable to waterborne diseases caused by enteric pathogens.

Helicobacter pylori virulence dupA gene: risk factor or protective factor?

Helicobacter pylori is the etiological agent of chronic gastritis, peptic ulcer, and gastric cancer. The duodenal ulcer-promoting gene dupA, which is located in the plasticity region of the H. pylori genome, is homologous to the virB gene which encodes a type IV secretion protein in Agrobacterium tumefaciens. Studies have shown associations between H. pylori dupA-positive strains and gastroduodenal diseases. However, whether dupA acts as a risk factor or protective factor in these diseases remains unclear. Therefore, in this study, we aimed to verify the presence of the dupA gene in infectious H. pylori strains in the Brazilian mid-west and to investigate its association with the clinical outcomes of patients with dyspepsia. Additionally, the phylogenetic origin of the strains was determined. Gastric biopsies from 117 patients with dyspepsia were analyzed using histological and molecular techniques. The hpx gene (16S rRNA) was used to screen for H. pylori infection, and positive samples were then subjected to dupA gene detection and sequencing. The estimated prevalence of H. pylori infection was 64.1%, with the dupA gene being detected in a high proportion of infectious strains (70.7%). Furthermore, a risk analysis revealed that for women, a dupA-positive H. pylori infection increased the chance of developing gastritis by twofold. The partial dupA sequences from isolated infectious strains in this work are similar to those of strains isolated in westerns countries. This study provides useful insights for understanding the role of the H. pylori dupA gene in disease development.

Streptomyces thermocerradoensis I3 secretes a novel bifunctional xylanase/endoglucanase under solid-state fermentation.

Lignocellulosic wastes can be potentially converted into several bioproducts such as glucose, xylo-oligosaccharides, and bioethanol. Certain processes, such as enzymatic hydrolysis, are generally needed to convert biomass into bioproducts. The present study investigated the production of xylanases and cellulases by Streptomyces thermocerradoensis I3 under solid-state fermentation (SSF), using wheat bran as a low-cost medium. The activities of xylanase and carboxymethyl cellulase (CMCase) were evaluated until 96 hr of incubation. The highest enzyme activity was observed after 72 hr of incubation. The crude enzyme extract was sequentially filtered, first using a 50 kDa filter, followed by a 30 kDa filter. Fraction 3 (F3) exhibited activities of both xylanase and CMCase. Xylanase and CMCase showed optimum activity at 70°C and pH 6.0 and 55°C and pH 6.0, respectively. The zymogram analysis showed a single activity band with a molecular mass of approximately 17 kDa. These findings provide strong evidence that the enzyme is a bifunctional xylanase/endoglucanase. This enzyme improved the saccharification of sugarcane bagasse by 1.76 times that of commercial cellulase. This enzyme has potential applications in various biotechnological procedures.

Improvement of bread making quality by supplementation with a recombinant xylanase produced by Pichia pastoris.

Xylanases (EC 3.2.1.8) are hydrolytic enzymes, which randomly cleave the ß-1,4-linked xylose residues from xylan. The synthetic gene xynBS27 from Streptomyces sp. S27 was successfully cloned and expressed in Pichia pastoris. The full-length gene consists of 729 bp and encodes 243 amino acids including 51 residues of a putative signal peptide. This enzyme was purified in two steps and was shown to have a molecular weight of 20 kDa. The purified r-XynBS27 was active against beechwood xylan and oat spelt xylan as expected for GH 11 family. The optimum pH and temperature values for the enzyme were 6.0 and 75 °C, respectively. The Km and Vmax were 12.38 mg/mL and 13.68 µmol min/mg, respectively. The r-XynBS27 showed high xylose tolerance and was inhibited by some metal ions and by SDS. r-XynBS27 was employed as an additive in the bread making process. A decrease in firmness, stiffness and consistency, and improvements in specific volume and reducing sugar content were recorded.