Evaluation of Phenotypic Variations in the Antibiotics Sensitivity of Escherichia Coli by Repeated Exposure

Enterobacteriaceae, in particular Escherichia coli, are habitual residents of the gastrointestinal tract, capable of causing a large number of infections. The MIC varies according to the bacterial strains and the antibiotics used, hence the need to carry out antibiotic sensitivity tests. The objective of this study is to evaluate the behavior of Escherichia coli after repeated exposure to the same antibiotic to demonstrate a possible correlation between excessive intake of antibiotics and bacterial resistance. A prospective and descriptive study was carried out in the Laboratory of Microbiology of Fundamental and Applied Biochemistry (Faculty of Sciences Antananarivo) during the month of November 2019. The strains studied were the reference strain Escherichia coli ATCC 25922 provided by the Laboratory and two clinical strains from the Microbiology Laboratory of the Joseph Ravoahangy Andrianavalona University Hospital Center (CHU JRA) Antananarivo. Repeated exposure to Tobramycin and Ofloxacin of these strains were performed. The results of our study showed that most E. coli is exposed to the antibiotic, the more it develops resistance. The evolution of E. coli\u27s sensitivity is different in the presence of Tobramycin with MICs up to 4 times the starting value while in the presence of Ofloxacin, the MIC increases to 125 times the initial value. This difference may be due to the different target of the antibiotic which causes the bacteria to develop variable mechanisms to escape it. Key words: E. coli - MIC - antibiotics - repeated exposur

Evaluation of Phenotypic Variations in the Antibiotics Sensitivity of Escherichia Coli by Repeated Exposure

Enterobacteriaceae, in particular Escherichia coli, are habitual residents of the gastrointestinal tract, capable of causing a large number of infections. The MIC varies according to the bacterial strains and the antibiotics used, hence the need to carry out antibiotic sensitivity tests. The objective of this study is to evaluate the behavior of Escherichia coli after repeated exposure to the same antibiotic to demonstrate a possible correlation between excessive intake of antibiotics and bacterial resistance. A prospective and descriptive study was carried out in the Laboratory of Microbiology of Fundamental and Applied Biochemistry (Faculty of Sciences Antananarivo) during the month of November 2019. The strains studied were the reference strain Escherichia coli ATCC 25922 provided by the Laboratory and two clinical strains from the Microbiology Laboratory of the Joseph Ravoahangy Andrianavalona University Hospital Center (CHU JRA) Antananarivo. Repeated exposure to Tobramycin and Ofloxacin of these strains were performed. The results of our study showed that most E. coli is exposed to the antibiotic, the more it develops resistance. The evolution of E. coli's sensitivity is different in the presence of Tobramycin with MICs up to 4 times the starting value while in the presence of Ofloxacin, the MIC increases to 125 times the initial value. This difference may be due to the different target of the antibiotic which causes the bacteria to develop variable mechanisms to escape it. Key words: E. coli - MIC - antibiotics - repeated exposur

Bacterial Vaginosis and Colonization by Gardnerella Vaginalis in Pregnant Women at Mother-Child University Hospital Centre Antananarivo between 2017 And 2018

Background: There was no study about bacterial vaginosis and colonization by Gardnerella vaginalis in pregnant women at Ambohimiandra Mother and Child Hospital Antananarivo.Objective: To determine the prevalence of bacterial vaginosis and colonization by Gardnerella vaginalis in pregnant women at Ambohimiandra Mother-Child Hospital and to raise awareness about the value of bacteriological examination of vaginal secretions in pregnant women in developing countries to avoid infectious complications during pregnancy.Materials and methods: This is an observational study conducted at Ambohimiandra Mother-Child Hospital between August 2017 and August 2018. All pregnant women carrying out a systematic bacteriological examination of vaginal sampling at the laboratory of this hospital university were included. Results: During the study, 130 pregnant women were realized a systematic bacteriological examination of vaginal sampling. Among of these, 30.76% had bacterial vaginosis and 11.53% were colonized with Gardnerella vaginalis. These cases were encountered in pregnant women at the 2nd and 3rd trimester.Conclusion: We describe the frequency of bacterial vaginosis and colonization by Gardnerella vaginalis during pregnancy in women with no complication at the time of sampling, finding a high frequency of bacterial vaginosis and a considerable rate of Gardnerella vaginalis carriage.Keywords - Bacterial vaginosis; Gardnerella vaginalis; Infectious; Pregnancy; Antananarivo