000			05296nam a2200301Ia 4500
005			20250223033106.0
008			231030s9999 xx 000 0 und d
049			_aDeposit
082			_a616.079
097			_aM.Sc
099			_aCai01.08.06.M.sc.2022.Re.B
100			_aReham Alaa Eldin Gamil Ahmed
245			_a“Biodegradation of Fluoroquinolones Microbial Isolates from Environmental Samples in Egypt” _cReham Alaa Eldin Gamil Ahmed ؛ Yasser El Mohammadi Ragab،Rania Abdelmonem Khattab،Yosra Ibrahim Nagy
246			_aاٌخىغ١ش اٌح١ٌٍ ٞٛفٍٛسٚو١ٌٕٔٛٛبث ػٓ ؽش٠ك اٌؼضالث اٌّ١ىشٚب١ت ِٓ ػ١ٕبث ب١ئ١ت فٟ ِظش
260			_c2022.
502			_aThesis (M.Sc.)-Cairo nivsersity,2022.
504			_a69-83 :Includes bibliogriphical references.
520			_aThe increase in the volume of industrial and urban wastewater produced as it contains toxic pharmaceutical compounds is considered one of the most important environmental problems worldwide. Antimicrobial agents are among the most commonly used drugs. Beta-lactams, macrolides, sulphonamides, FQs, and tetracyclines are the most important antibiotic groups used in both human and veterinary medicine. The high global consumption and high percentage of antibiotics (up to 90%) that may be excreted without undergoing metabolism have resulted in their widespread presence in the environment, and the widespread and improper use of antibiotics in livestock, human and pets have resulted in the development of antibiotic-resistant bacteria among pathogenic bacteria, rendering current antibiotics ineffective in the treatment of numerous diseases thus, the aim of this study is to investigate the potential of CIP and LEV biodegradation by microbial populations, and to identify the metabolites/transformation products originated during biodegradation process. In addition, the current study aimed to shed some light on the enzymes involved in FQs biodegradation and possible biodegradation pathways. Two bacterial consortia that can degrade CIP and LEV were isolated from wastewater, identified as E. miricola, A. baumannii and K. pneumoniae the optimal conditions for maximum degradation were explored and we found that the optimum degradation conditions for both CIP and LEV in sample 1 (A. baumannii and K. pneumoniae) were temperature 30 ° C, pH 5, agitation rate 180 rpm and without UV application. For sample 2 (E. miricola and K. pneumoniae), temperature 30 °C, pH 7, agitation rate 180 rpm and without UV application represent the optimum conditions for both CIP and LEV biodegradation. CIP was readily degraded by the two bacterial consortia by 50 % while LEV was degraded by 50 % and 30 % for sample one and two respectively at concentration 1 mg/L within 48 h of incubation in liquid medium. The biodegradation products were identified by liquid chromatography tandem mass spectrometry. Seven major metabolites were revealed from the biodegradation of each FQ (CIP and LEV) by the two bacterial consortia. The relative abundance between isolates of the two bacterial consortia during the biodegradation of CIP and LEV was investigated. The data revealed that in sample 1 initially, K. pneumoniae was more abundant than A. baumannii. However, as the CIP and LEV biodegradation process progressed, the ratio became the same. Interestingly, the initial ratio between the bacterial isolates in sample 2 (K. pneumoniae and E. miricola) was essentially the same, but as the biodegradation process proceeded, the ratio was changed and E. miricola became the foremost Summary 83 abundant one. The individual bacterial isolates in both consortia were molecularly screened for aac (6 ’) –Ib-cr gene that is involved in the degradation of FQs. All four isolates were positives for the gene. The aac(6′)-Ib-cr variant was distinguished from the wild type gene by direct sequencing and confirming the absence of the BstF5I restriction site present in the wild-type gene. The role of the enzyme cytochrome P450 in the breakdown of FQS was investigated by the addition of CYP450 inhibitor ABT. The concentration of CIP and LEV was measured by HPLC-DAD after 48 hours of incubation in absence and presence of 1- aminobenzotriazole. Complete inhibition of the biodegradation of CIP and LEV in the presence of 1-aminobenzotriazole indicated the possible involvement of CYP450 enzymes. According to our research, various biodegradation pathways have been proposed, including cleavage of piperazine ring, substitution of Flourine atom, acetylation, decarboxylation, and hydroxylation, as the main transformation reactions catalyzed by CYP450 and the (aac (6 ′) - Ib-cr). The results of the phytotoxicity assay revealed that the two bacterial consortia can be used in the bioremediation of CIP and LEV yielding non phytotoxic compounds, thus, providing an environmentally safe approach for dealing with FQs environmental pollution
650			_aMicrobiology
653			_aPharmacy
700			_aYosra Ibrahim Nagy
856			_uhttp://172.23.153.220/th.pdf
905			_aMohamady
942			_cTH _2ddc
999			_c163698 _d163698
336			_2rda content _atext
337			_2rdamedia _aUnmediated
338			_2rdacarrier _avolume