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The purpose of this study was to determine the influence of environmental pH on production of biofilms and virulence genes expression in Pseudomonas aeruginosa.

Among 303 clinical and environmental samples 109 (61 + 48) isolates were identified as clinical and environmental P. aeruginosa isolates, respectively. Clinical samples were obtained from patients in the Al-Yarmouk hospital in Baghdad city, Iraq. Waste water from Al-Yarmouk hospital was used from site before treatment unit to collect environmental samples. The ability of producing biofilm at various pH levels was examined by microtiter plate and the prevalence of Alg D, Psl A and Pel A was determined by quantitative real time-polymerase chain reaction (qRT-PCR).

This study showed that the ability of clinical and environmental isolates to biofilm development was observed in 86.9% and 85.42% of clinical and environmental isolates, respectively. As well as, the environmental P. aeruginosa isolates showed the highest biofilm production at pH 7. Clinical isolates showed the highest genes expression of Alg D, Psl A and Pel A as compared to environmental isolates with pH change. In general, both clinical and environmental isolates formed biofilm and carried AlgD, PslA and PelA genes. Also, alkaline pH was favored for biofilm production.

There are very few studies done to find out the influence of environmental pH on production of biofilms and virulence genes expression in Pseudomonas aeruginosa. This study is unique as it has highlighted the influence of environmental pH on the ability of clinical and environmental isolates to biofilm development and genes expression.

The purpose of this paper is to assess the occurrence of the extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamase genes in 144 Escherichia coli isolates recovered from 160 vegetable salad samples.

Among the 144 E. coli isolates recovered from 160 vegetable salads, 17 (12 percent) ceftazidime-resistant isolates were screened for ESBL production with the double disk-diffusion test. The ESBL-producing isolates were characterized for antimicrobial resistance, the presence of virulence genes and plasmid-mediated quinolone resistance (PMQR) determinants. The isolates were also subjected to phylogenetic group typing. The existence of plasmid AmpC genes and mutations in the regulatory region of the chromosomal AmpC gene was assessed using polymerase chain reaction (PCR) and sequencing. All β-lactamase isolates were further characterized by pulsed-field gel electrophoresis to determine the genetic relatedness.

Overall, 17 (12 percent) of the 144 E. coli isolates studied were ceftazidime resistant. Among the 17 isolates, 13 (77 percent) were multidrug resistant and four (23.5 percent) were ESBL producers. The bla CTX-M14 was the only gene detected. Of the 12 AmpC-producing isolates, three (18 percent) harbored plasmid-encoded AmpC and sequencing analysis of the chromosomal AmpC genes revealed mutations in the promoter/attenuator region. PMQR determinants were detected in 9 (52 percent) isolates. A was the most prevalent phylogenetic group (56 percent), followed by groups B1 (31 percent), D (6 percent), and B2 (6 percent). PCR showed that six (50 percent) ESBL/AmpC-producing E. coli isolates carried one and/or two virulence genes. Pulsed-field gel electrophoresis showed no epidemiological relationship between these isolates.

This study places vegetable salads within the spectrum of ecological niches that may be vehicles for antibiotic-resistant bacteria/genes with clinical interest and these findings are worthy of attention as their spread to humans by ingestion cannot be dismissed.

Vegetable salads, despite their recognized health benefits, are an increasingly common cause of foodborne illness worldwide. The purpose of this paper is to determine the prevalence of E. coli with virulence genes in ready-to-eat raw mixed vegetable salads sold in collective catering in Abidjan.

A total of 436 strains of E. coli were isolated from 306 ready-to-eat raw mixed vegetables salads and then identified biochemically and molecularly based on the uidA gene responsible for beta-glucuronidase activity. The virulence genes were determined by polymerase chain reaction.

The prevalence in vegetable salads of E. coli with virulence genes was 35.3 percent. The distribution of pathovars was 21.2 percent enterotoxigenic (ETEC), 4.9 percent enteropathogenic (EPEC), 0.7 percent Shigatoxigenic (STEC), and 7.5 percent Enteroaggregative E. coli (EAEC). It appears from the study that vegetable salads sold in collective catering in Abidjan are at risk for contamination by E. coli pathovars.

Processing conditions for these salads during preparation appear to be hygienically insufficient, so measures to control the risk of contamination are necessary.

Broad-spectrum cephalosporin resistance is rapidly increasing in Escherichia coli, representing a food safety problem. The purpose of this paper is to characterize eight extended-spectrum-ß-lactamase (ESBL) and acquired AmpC ß-lactamase-producing E. coli isolates and virotypes associated, obtained from chicken and pork food samples in Puebla, Mexico.

Samples (36 from chicken and 10 from pork) were cultured on Levine agar plates supplemented with cefotaxime (2 mg/L) for isolation of cefotaxime-resistant (CTXR) E. coli. CTXR-E. coli isolates were detected in 33 of 46 samples (72 percent), and one isolate/sample was characterized (28 from chicken and 5 from pork), for ESBL production, phylogenetic group, sequence typing, resistance and virulence genes by PCR and sequencing.

Results showed 16 ESBL-E. coli (35 percent) (12/16 belonging to phylogroup B1) and 8 CMY-2-E. coli (17 percent). ESBL detected were as follows (number of isolates): CTX-M-2 (8); CTX-M-1 (2); CTX-M-15 (1); SHV-2a (4) and TEM-52c (1). In total, 20 different sequence types (STs) were identified among the ESBL- or CMY-2-producing E. coli strains, which included four new ones. The CTX-M-15 β-lactamase was detected in one E. coli ST617-ST10 Cplx-B1 strain that also carried ibeA gene. One CMY-2-positive strain of lineage ST224-B2 was detected and it carried the qnrA1 gene.

In this study, a ST131-based virotyping scheme for strains from food of animal origin was established since this kind of strains constitutes an important vehicle of virulent ESBL- and CMY-2-producing E. coli isolates, which could be transmitted to humans by direct contact or through the food chain.

This study aims to study the distribution characteristics of antibiotic resistance in direct-eating food and analysis of Citrobacter freundii genome and pathogenicity. Residual antibiotics and antibiotic resistance genes (ARGs) in the environment severely threaten human health and the ecological environment. The diseases caused by foodborne pathogenic bacteria are increasing daily, and the enhancement of antibiotic resistance of pathogenic bacteria poses many difficulties in the treatment of disease.

In this study, six fresh fruits and vegetable samples were selected for isolation and identification of culturable bacteria and analysis of antibiotic resistance. The whole genome of Citrobacter freundii isolated from cucumber was sequenced and analyzed by Oxford Nanopore sequencing.

The results show that 270 strains of bacteria were identified in 6 samples. From 12 samples of direct food, 2 kinds of probiotics and 10 kinds of opportunistic pathogens were screened. The proportion of Citrobacter freundii screened from cucumber was significantly higher than that from other samples, and it showed resistance to a variety of antibiotics. Whole genome sequencing showed that Citrobacter freundii was composed of a circular chromosome containing signal peptides, transmembrane proteins and transporters that could induce antibiotic efflux, indicating that Citrobacter freundii had strong adaptability to the environment. The detection of genes encoding carbohydrate active enzymes is more beneficial to the growth and reproduction of Citrobacter freundii in crops. A total of 29 kinds of ARGs were detected in Citrobacter freundii, mainly conferring resistance to fluoroquinolones, aminoglycosides, carbapenem, cephalosporins and macrolides. The main mechanisms are the change in antibiotic targets and efflux pumps, the change in cell permeability and the inactivation of antibiotics and the detection of virulence factors and ARGs, further indicating the serious risk to human health.

The detection of genomic islands and prophages increases the risk of horizontal transfer of virulence factors and ARGs, which spreads the drug resistance of bacteria and pathogenic bacteria more widely.

Current study was carried to detect the presence of pathogenic bacteria including the drug-resistant ones from milk and milk products. The paper aims to discuss these issues.

Twenty-six raw milk samples from ten different areas, 28 pasteurized milk samples from 12 different companies and 26 yogurt samples from ten different sources in Dhaka city were microbiologically analyzed through cultural and biochemical identification of the isolates. Drug resistance trait was also determined by the Kirby-Bauer method on Muller-Hinton agar.

Out of 80 samples studied, 74 were found to harbor pathogens within a range of 102-104 cfu/ml, including Escherichia coli, Salmonella spp., Staphylococcus aureus, and Vibrio spp. The study of antibiogram revealed that most of the isolates were resistant against most of the commonly used antibiotics.

Employment of only cultural/ biochemical tests excluding the molecular detection of virulence and/or antibiotic resistance genes might stand as a shortfall of the study. Nevertheless, such basic approach of microbiology can make this type of study replicable in the resource poor settings in the other developing countries.

Routine detection of drug-resistant bacteria can further unveil the complications in chemotherapy during the endemic food borne diseases.

The study outcome/knowledge would aid to a better public health management especially in the developing countries.

The presence of drug-resistant pathogenic bacteria in most of the tested milk samples poses a great public health threat, especially to the children. Therefore, the study revealed the necessity of maintaining proper hygienic practice and care in handling and processing of milk and milk products.

A meeting report on the Keystone Symposium “Systems Approach to Plant Biology”, Big Sky, Montana, 26‐31 January, 2001. This symposium, sponsored by several plant biotech companies, brought together both industrial and academic researchers to plot bolder strategies for high‐throughput plant biological research. Broad‐ranging discussions covered historical discoveries, recent developments and exciting new trends that are emerging in this highly dynamic field. Participants from around the world appeared to be energized by the exciting possibilities for determining and, ultimately, controlling metabolic pathways and processes while recognizing that there is still much to do in order to understand the biological systems of all known genes.

The purpose of the paper is to emphasize on contamination sources of freshly cultivated vegetables commonly consumed by the Bangladeshi people. Several local studies have been conducted to detect the microbial contamination within fresh vegetables, plantation lands and the irrigation waters separately; however, the correlation of microbial contamination between the fresh produces and the surrounding environment has not been clarified.

Bottle gourd (Lagenaria siceraria), pumpkin (Cucurbita pepo), radish (Raphanus sativus) and eggplant (Solanum melongena); their plantations soils and the fertilizers applied across the agricultural lands; and, finally, the irrigation waters used were analyzed from nine districts of Bangladesh using conventional microbiological and biochemical methods.

Almost all vegetable samples studied were found to be immensely contaminated with bacteria and fungi. Among the pathogens, Klebsiella spp., Staphylococcus spp. and Pseudomonas spp. were found to be dominant. Besides, massive microbial growth was also observed in the plantation soils and fertilizers, including Klebsiella spp., Pseudomonas spp., Bacillus spp., Listeria spp., Escherichia coli and Vibrio spp. Existence of the fecal coliforms, E. coli, Klebsiella spp., Salmonella spp. and Listeria spp., was noticed in the irrigation waters.

Although the present study revealed the combined results connecting the vegetable contamination aspect with the knowledge on microbiology ultimately in the food chain, implementation of molecular studies detecting the virulence genes both in the fresh produces and the plantation soils, fertilizers and the irrigation waters would further clarify the microbial dissemination mechanism.

Earlier studies demonstrated the ability of water bodies to disseminate numerous microorganisms into the plantation soils, and to some extent unraveled the ability of organic fertilizers to propagate pathogenic bacteria into the vegetation objects. These microorganisms may pose as a threat to vegetables, particularly by limiting crop production as well as the shelf life of the fresh produces.

The scenario of microbial divergence not only in the vegetables but also within the surroundings is gradually being heightened in Bangladesh principally due to the malpractice of sanitation, dumping the agricultural lands with feces, improperly controlled septic systems, waste water runoff across the agricultural lands, etc. Therefore, the preliminary and replicable experimental approach described in the current study would be feasible for all other developing countries to maintain the public health safety.

Growth and proliferation of microorganisms both in the vegetable samples and the environmental samples nearly to a similar extent indeed projected for the first time in Bangladesh, the agricultural perspective of the contamination sources of vegetables. Such knowledge would aid in the existing knowledge on the hygienic processing during crop production and harvesting for the sake of better consumer safety management.

There is an immense concern in the international community about controlling the outburst of infectious diseases. An essential step towards diminishing it is the development of an adequate detection system. Among the huge plethora of microorganisms which may infect the human body, Streptococcus pyogenes is important one which infects the upper respiratory tract leading to sore throat, which eventually develops into rheumatic heart disease (RHD) in the absence of timely treatment. A major process in controlling the infection is to detect it at an early stage. Hence, there is a need to develop detection tools which are both rapid and reliable.

Different types of diagnostic methods are available for identification, but the most commonly used are culturing, staining and rapid antigen detection tests. For better sensitivity and specificity, this review describes the development of biosensor. Compared with the current available methods, which are usually cumbersome, time-consuming and expensive, this approach features sequence specificity, cost efficiency, rapid and ease of use.

This review outlines various sensors which are available for the detection of Streptococcus pyogenes which causes human RHD. The working scheme of the sensors, their sensitivity and limitation of detection has been described in the review.

The review fulfills an acknowledged the need to study various sensors that are available for the detection of Streptococcus pyogenes, causing human RHD.

The purpose of this paper was to identify Serratia marcescens to extract and purify prodigiosin pigment to evaluate the antibacterial potential of the pigment.

Samples were collected from shrimp aquaculture ponds. Species identification was conducted using morphological, biochemical and molecular tests. Pigment extraction and purification were carried out using column chromatography. The antibacterial effect of crude and purified prodigiosin pigment was evaluated on Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus as biofouling bacteria. In addition, the interaction between prodigiosin and proteins involved in biofilm formation was evaluated using molecular docking.

The results of prodigiosin extraction with solvents showed the highest percentage of pigment presence with methanol solvent in the second day of culture. The chemical structure of pure prodigiosin obtained from the column chromatography was confirmed by Fourier-transform infrared spectroscopy. Both crude and purified pigments exhibited antibacterial effects against selected bacterial strains. The antibacterial effect of the purified pigment was higher, and the highest antibacterial effect was observed on B. subtilis. Prodigiosin docking was carried out with all target proteins, and the docked energy in all of them was at an acceptable level.

Prodigiosin extracted from S. marcescens can be used as a bioactive compound to design and manufacture of anti-biofouling and anti-biofilm formation products to use extensively for industrial applications as a natural color in marine industries, food industry, cosmetics and textile productions.