جستجوی مقالات مرتبط با کلیدواژه « bacterial pathogens » در نشریات گروه « پزشکی »

Periodontal diseases are resulted from gum infections and dental plaques, which are mainly caused by the bacterial agents. Since dental monitoring includes important prognostic roles, the aim of this study was to detect the most common periodontal pathogenic bacteria in children.

A total of 200 clinical samples were collected from dental plaques and gingival grooves. Tar- get-specific primers were designed for hbpA in Aggregatibacter actinomycetemcomitans, fimA in Porphyromonas gingivalis and 16S rRNA in Prevotella intermedia, Tannerella forsythia and Treponema denticola. Then, a multiplex polymerase chain reaction method was optimized for the highlighted bacterial agents.

In general, the highest and the lowest bacterial prevalence rates belonged to Tannerella forsythia (88%) and Por- phyromonas gingivalis (13%), respectively. Furthermore, prevalence rates of Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Treponema denticola were 25, 21 and 45% in samples, respectively.

There were significant associations between dental/oral health and microbial community. Metabolism of the oral bacteria, including biofilm formation, can affect gums and develop dental plaques and hence dental caries, especially in children. Early diagnosis of dental caries in children via rapid, accurate molecular methods can increase the diagnostic capacity in clinical cases and therefore prevent periodontal infections in adulthood.

 Computers and other electronic devices are a requisite aspect of people’s lives globally for multiple purposes, including education, entertainment, and communication.

 This study investigated the bacterial contamination of desktop computer keyboards (as a reservoir of pathogens) in different departments of Mazandaran University of Medical Sciences, Sari, Northern Iran, from September 2018 to February 2019.

 In this descriptive cross-sectional study, samples were obtained from computer keyboards with sterile swabs and cultured on blood agar and eosin methylene blue agar. Standard microbiological methods were used to identify bacterial isolates. Then, the antimicrobial susceptibility testing of the isolates was performed using the Kirby-Bauer method based on the CLSI procedure.

 In total, 58 bacterial strains were isolated from the collected samples. The isolates included 23 (39.7%) Staphylococcus epidermidis, 15 (25.9%) Staphylococcus aureus, 14 (24.1%) Bacillus spp., 3 (5.2%) Klebsiella pneumoniae, 2 (3.4%) Pseudomonas aeruginosa, and 1 (1.7%) Escherichia coli. All Gram-positive bacteria were resistant to penicillin, whereas the most resistance rate among Gram-negative bacteria was observed against ciprofloxacin, ceftazidime, and cephalothin.

 Due to the presence of opportunistic pathogens on computer keyboards, personal hygiene and periodic cleaning of keyboards with disinfectants is necessary to prevent the further spread of these bacteria.

This work described the isolation and identification of bacteriocin-producing lactic acid bacteria (LAB) from ‘Kati’(a sorghum based fermented food), and to evaluate the antibacterial effect of bacteriocin on selected pathogenic bacteria. The identities of the isolates were revealed to be as Lactobacillus plantarum, L. brevis, L. fermentum KAT1, L. fermentum KAT2 and Lactococcus lactis using 16S rRNA gene sequence analysis. Out of 28 LAB, five were found to inhibit selected pathogenic bacteria namely; Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Bacillus cereus. The unpurified bacteriocins produced by the isolated LAB were characterized with respect to the effect of temperature, pH and surfactant. The test isolates showed activities of 6400, 6400, 6400, 3200 and 1600 AU/ml respectively. Crude bacteriocin from L. brevis and L. lactis were the most heat stable at 121ºC for 60 min. Bacteriocins from L. plantarum, L. lactis and L. fermentum KAT1 showed the highest antibacterial activity and stability at pH 2.0 to 6.0. Exposure to Tween 20 increased the bacteriocin activity of the LAB isolates except for L. fermentum KAT2 where loss of activity occurred. The findings from this study suggest that bacteriocinogenic LAB present in ‘kati’ have potentials to inhibit pathogenic/spoilage microorganisms in foods.

  Efflux-based systems may play a role in resistance to fluoroquinolones in Gram-negative pathogenic bacteria. Extracts of some medicinal plants contain molecules that can act as efflux pumps inhibitors. In this study, we aimed to evaluate antibacterial activities of ethanolic and chloroform extracts of Cinnamomum zeylanicum and their possible synergistic activity with ciprofloxacin against some Gram-negative pathogenic bacteria. We also analyzed the extracts for presence of efflux pump inhibitors against the examined bacteria.                Powdered dried leaves and branches of C. zeylanicum were extracted with ethanol (85%) and chloroform by the maceration method. Minimum inhibitory concentrations of the extracts alone or combined with ciprofloxacin and phenylalanine-arginine β-naphthylamide (an efflux pump inhibitor) were determined against Pseudomonas aeruginosa, Acinetobacter bummani, Escherichia coli and Salmonella enteritidis using the double serial microdilution method.              The extracts of C. zeylanicum inhibited the growth of all studied bacteria. Synergistic effects were noted between the extracts and ciprofloxacin against all tested bacteria other than P. aeruginosa. Ciprofloxacin efflux pumps in E. coli, S. enteritiditis and A. baumannii were inhibited by the extracts of C. zeylanicum.              The extracts of C. zeylanicum could be used as ciprofloxacin-potentiating agents against some Gram-negative pathogens.