Urinary tract infections (UTIs), caused by Escherichia coli 80% to 85% of the time, are one of the most important causes of morbidity and health care spending affecting persons of all ages. These infections lead to many difficult problems, especially increasing resistance to antibiotic drugs. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. In this study, we have investigated the antibacterial activity of five medicinal plant essential oils against UTIs caused by E. coli using disc diffusion and minimal inhibition concentration (MIC) methods. In addition, biofilm inhibitory action of oils was realized by crystal violet. Gas chromatography–mass spectrometry (GC–MS) analysis showed a variability between oils in terms of compound numbers as well as their percentages. Antibacterial activity was observed only in cases of Origanum majorana, Thymus zygis and Rosmarinus officinalis, while Juniperus communis and Zingiber officinale did not showed any effect towards E. coli isolates. T. zygis essential oil demonstrated the highest antibacterial activity against E. coli isolates, followed by O. majorana and R. officinalis. Further, oils showed high biofilm inhibitory action with a percentage of inhibition that ranged from 14.94% to 94.75%. R. officinalis oil had the highest antibiofilm activity followed by T. zygis and O. majorana. Accordingly, tested oils showed very effective antibacterial and antibiofilm activities against E. coli UTIs and can be considered as good alternative for antibiotics substitution.

Methicillin-resistant Staphylococcus aureus is a major human pathogen that poses a high risk to patients due to the development of biofilm. Biofilms, are complex biological systems difficult to treat by conventional antibiotic therapy, which contributes to >80% of humans infections. In this report, we examined the antibacterial activity of Origanum majorana, Rosmarinus officinalis, and Thymus zygis medicinal plant essential oils against MRSA clinical isolates using disc diffusion and MIC methods. Moreover, biofilm inhibition and eradication activities of oils were evaluated by crystal violet. Gas chromatography–mass spectrometry analysis revealed variations between oils in terms of component numbers in addition to their percentages. Antibacterial activity testing showed a strong effect of these oils against MRSA isolates, and T. zygis had the highest activity succeeded by O. majorana and R. officinalis. Investigated oils demonstrated high biofilm inhibition and eradication actions, with the percentage of inhibition ranging from 10.20 to 95.91%, and the percentage of eradication ranging from 12.65 to 98.01%. O. majorana oil had the highest biofilm inhibition and eradication activities. Accordingly, oils revealed powerful antibacterial and antibiofilm activities against MRSA isolates and could be a good alternative for antibiotics substitution.

In this study we investigated the phenotypic slime production of Vibrio alginolyticus and Vibrio parahaemolyticus strains, food-borne pathogens, using a Congo red agar plate assay. Furthermore, we studied their ability to adhere to abiotic surfaces and Vero cells line. Our results showed that only V. alginolyticus ATCC 17749 was a slime-producer developing almost black colonies on Congo red agar plate. Adherence to glace tube showed that all V. alginolyticus strains were more adherent than V. parahaemolyticus. Only V. alginolyticus ATCC 17749 was found to be able to form biofilm on polystyrene microplate wells (OD570 = 0.532). Adherence to Vero cells showed that all tested strains were non adherent after 30 min, however after 60 min all the studied strains become adherent. The percentage of adherence ranged from1.23% to 4.66%. Neste estudo, investigou-se a produção de muco por cepas de Vibrio alginolyticus e Vibrio parahaemolyticus através do teste em placa de ágar com vermelho congo. Estudou-se também a capacidade de adesão à superfícies abióticas e células Vero. Os resultados indicaram que somente V. alginolyticus ATCC 17749produziu muco, formando colônias quase negras nas placas de ágar com vermelho congo. O teste de adesão a tubos de vidro indicou que as cepas de V. alginolyticus foram mais aderentes do que as de V. parahaemolyticus. Somente V. alginolyticus ATCC 17749 foi capaz de formar biofilme nos poços das microplacas de poliestireno (OD570=0,532). Testes de adesão a células Vero mostraram que nenhuma das cepas apresentou adesão em 30 min, mas todas aderiram após 60 min. A porcentagem de adesão variou de 1,23% a 4,66%

Klebsiella pneumoniae is an opportunistic pathogen responsible for a significant proportion of nosocomial and community-acquired infections. Genotypic variation in K. pneumoniae populations is a major barrier to control public health risk associated with pathogen. In this work, thirty K. pneumoniae were recovered from hospital and were tested for their resistance to antibiotics. Genetic variability of the isolates was performed using PCR based on genes coding for porins and efflux pumps, (GTG)5 and BOX repetitive sequences. K. pneumoniae showed heterogenicity of resistance to antibiotics based on gender or specimen type. Further, out of 30 isolates, 25 different profiles were found and 83.33% are multidrug-resistant. PCR detection of genes coding for porins and efflux pumps revealed seven different genotypes and strong correlation between antibiotics resistance profiles and investigated genes. PCR genomic fingerprinting showed high genetic diversity of K. pneumoniae. BOX-PCR and (GTG)5 generated 18 and 19 clusters with discriminatory indexes 0.97 and 0.98, respectively at 80% of similarity. K. pneumoniae clinical isolates showed high phenotypic and genetic variability, and many strains can be circulating simultaneously. This genetic variability should be taken into consideration when designing strategies for controlling K. pneumoniae outbreaks. In addition, a significant correlation, was detected for the first time, between (GTG)5-genotyping and antibiotic resistance patterns of K. pneumoniae and could be valuable in the prediction of antibiotic resistance profiles of K. pneumoniae.