Study of Biofilm Formation and Escherichia coli Biofilm Resistance Pattern Isolated from Urinary Culture Infections
Study of Biofilm Formation and Escherichia coli Biofilm Resistance Pattern Isolated from Urinary Culture Infections
somayyeh taghizadeh,1,*zahra Hojjati Bonab,2Sanam Roghanforoush,3
1. PhD of microbiology 2. Assistant Professor of Microbiology, Faculty of Basic Sciences, Islamic Azad University Bonab Branch, Bonab, Iran 3. M.Sc. of Microbiology, Faculty of Basic Sciences, Islamic Azad University Bonab Branch, Bonab, Iran
Introduction: Urinary tract infections are one of the most commonly nosocomial infections that it is cloned by Escherichia coli bacteria and it affects the host's mucous membrane. The increased resistance of bacteria to antibiotics, as well as the biofilm adhesion of infectious bacteria to the glass and plastic surfaces of hospital equipment, is another issue that causes the problem in treating this type of bacterial urinary tract infection. The aim of this study is to study the biofilm formation and bacterial resistance and biofilm resistance to antibiotics.
Methods: In this study, 150 samples of suspected urinary tract infection were collected; cultured on McConkey medium; and finally stained. Catalase test and culture in differential media (TSI, Simon Citrate, SIM, MR and VP) were used for isolation of Escherichia coli bacteria from other gram-negative bacilli from EMB Agar medium; and for completely identification of Escherichia coli bacteria in the positive samples. Routine biochemical methods and Antibiogram tests were performed to detect antibacterial sensivity of the bacteria. Biofilm formation of this bacterium was performed by Microtiter Plate and Tubal methods. Therefore, to study of antibiotical and probiotical resistance patterns on Escherichia coli biofilm, antibiogram discs of ampicillin (AM), ciprofloxacin (CP), cefixime (CFM), co-trimoxazole (STX), and gentamicin (GM) anticotics were used. In the next step, antibiotical resistanc pattern of Nystitin was performed on Escherichia coli biofilm and free Escherichia coli bacteria, and determination of MIC and MBC points. Finally, the effect of Nystitin anticotic on planktonic and biofilm bacteria was determined.
Results: The results showed that of total 150 initial samples, 23 samples (15.33%) were infected; by using conventional biochemical methods and Antibiogram test determined that 18 samples (78.26%) of 23 infected samples contained Escherichia coli bacteria. The staining of bacteria identified the gram-negative bacilli species and then, by cultivate the specimens on the differential medium, the bacteria that had green gloss was isolated as Escherichia coli. The result of catalase test was also positive. The isolated had thses bichemistrial features: citrate-negative, catalase-positive, endol-positive and motile. Also, it is determined that the bactira within the urinary specimens have the highest resistance (50 %) to co-trimoxazole and the least resistance (5.55%) to gentamicen; and probiotic Lactobacillus acidophilus had no effect on planktonic Escherichia coli bacteria; and also, it was not inffective on the biofilm. During the study of antibiotic resistance pattern of Nystatin on biofilm and free Escherichia coli, it was found that the biofilm of Escherichia coli is much more resistant than biofilm of Planktonic Escherichia coli bacteria. The final test results also showed that Nystatin antibiotic did not affect on the biofilm but in the concentration of 0.02% (125 µL) was effective on Planktonic bacteria. These results were similar to the results of several studies. For example, in a study by Abdollahi Kheirabadi and colleagues (2012), the resistance of Escherichia coli to antibiotics was increased by ciprofloxacin; and in the study of Tajwidi et al. (2013), the highest resistance to co-trimoxazole was observed. Boniadian et al. (2013) reported the low sensitivity of Escherichia coli to cefixime. Zarrinfar (2016) and Fazeli (2004) also confirmed the lack of effect of probiotics on growth of Escherichia coli.
Conclusion: As a result, it can be said that it is better to did not use from co-trimoxazole as an epileptic treatment in the treatment of urinary tract infections caused by Escherichia coli, and it prevented to froming of biofilm at any surface, because bacterial biofilm is more resistant and probiotics do not show antimicrobial effects on biofilm.