Staphylococcus aureus is a well-known foodborne pathogen. The aim of this study was to investigate the presence of S. aureus isolated from serving utensils in food processing environments in Mymensingh city, Bangladesh and to determine their antibiogram and resistance determinants. A total of 120 environmental samples were collected from different food settings. Isolation and identification were conducted using conventional biochemical tests. Molecular identification of isolates and detection of methicillin and vancomycin resistance were done using primer-specific polymerase chain reaction (PCR) targeting Tuf , nuc , mecA , and mecC genes. Antibiotic sensitivity tests were performed, and resistance genes were also detected by amplifying bla TEM , vanA, vanB, and vanC genes. Among the 120 samples, 81 (67.5%) were positive for Staphylococcus spp. and 41 (50.62%) were positive for the nuc -gene. Among the 41 isolates, 5 (12.20%) were positive for mecA , but none were positive for the mecC gene. A total of 12.2% of the isolates were vanC -positive, of which 4 isolates (9.76%) were also positive for the mecA gene. Antibiotic sensitivity testing revealed that all S. aureus isolates (100%) from hotel samples were sensitive to ciprofloxacin and chloramphenicol, 90.32% were sensitive to doxycycline, and 80.65% were sensitive to streptomycin. Conversely, all isolates (100%) were resistant to ampicillin, and 29.03% were resistant to vancomycin. All S. aureus isolates obtained from non-hotel samples were susceptible to chloramphenicol, ceftriaxone, ciprofloxacin, doxycycline, meropenem, and vancomycin; however, 40% of isolates were resistant to novobiocin. Among the hotel isolates, 29 (93.55%) of the ampicillin-resistant isolates harbored the blaTEM gene while 5 (55.55%) of the vancomycin-resistant isolates harbored the vanC gene. Four of the five vanC positive isolates were also positive for the mecA gene. The presence of methicillin-resistant S. aureus (MRSA) which is also vancomycin-resistant in food processing environments is a threat to public health. This is the first report on the molecular detection of methicillin and vancomycin-resistant S. aureus isolated from food processing environments in Bangladesh.
Background Babesia and Theileria are potential threats to the livestock industry, causing considerable economic losses. These tick‐borne blood parasites are more prevalent in crossbred cattle than local cattle in Bangladesh. Objectives To confirm the species of Babesia and Theileria in crossbred cattle from the northern part of Bangladesh using conventional and molecular tools. Methods A total of 385 crossbred cattle blood samples were subjected to DNA extraction and PCR. For molecular detection, B. bigemina rhoptry‐associated protein 1a, B. bovis spherical body protein‐4, and Theileria spp. 18S rRNA were used as the marker genes. Results Using PCR, only 72 (18.7%) samples were found piroplasm positive, of which 12.2% Theileria, 4.7% Babesia, and 1.8% mixed infections. Both Babesia (7.3%), Theileria (7.7%) and mixed (2.8%) infections were detected in Sirajganj, and only Theileria (20.4%) was detected in Rangpur district. By PCR and nPCR we detected B. bigemina and T. annulata in Sirajganj district, and Theileria sp. in Rangpur district. The target gene sequences of isolated pathogens confirmed B. bigemina and T. annulata, and Theileria sp from these samples. Blood smears of all samples were also examined microscopically for Babesia and/or Theileria spp. and 14.3% of samples were found positive, of which 5.9% Babesia and 8.3% Theileria. Generally, the pathogens detected in Sirajgang and Rangpur were genetically related to South Asia, particularly South East Asian isolates. Conclusions These findings provide information for a better understanding of the epidemiology of Babesia and Theileria as well as to improve the approaches for diagnosis and control of tick‐borne diseases in Bangladesh.
Natural colorants have been used in several ways throughout human history, such as in food, dyes, pharmaceuticals, cosmetics, and many other products. The study aimed to isolate the natural colorant-producing filamentous fungi Aspergillus niger from soil and extract pigments for its potential use specially for food production. Fourteen soil samples were collected from Madhupur National Park at Madhupur Upazila in the Mymensingh district, Bangladesh. The Aspergillus niger was isolated and identified from the soil samples by following conventional mycological methods (cultural and morphological characteristics), followed by confirmatory identification by a polymerase chain reaction (PCR) of conserved sequences of ITS1 ribosomal DNA using specific oligonucleotide primers. This was followed by genus- and species-specific primers targeting Aspergillus niger with an amplicon size of 521 and 310 bp, respectively. For pigment production, a mass culture of Aspergillus niger was conducted in Sabouraud dextrose broth in shaking conditions for seven days. The biomass was subjected to extraction of the pigments following an ethanol-based extraction method and concentrated using a rotary evaporator. Aspergillus niger could be isolated from three samples. The yield of extracted brown pigment from Aspergillus niger was 0.75% (w/v). Spectroscopic analysis of the pigments was carried out using a UV–VIS spectrophotometer. An in vivo experiment was conducted with mice to assess the toxicity of the pigments. From the colorimetric and sensory evaluations, pigment-supplemented products (cookies and lemon juice) were found to be more acceptable than the control products. This could be the first attempt to use Aspergillus niger extracted pigment from soil samples in food products in Bangladesh, but for successful food production, the food colorants must be approved by a responsible authority, e.g., the FDA or the BSTI. Moreover, fungal pigments could be used in the emerging fields of the food and textile industries in Bangladesh.
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