Majority of ESBLs and AmpC beta-lactamases producing GNB were isolated from urine specimens 47.5% (116/338). Ampicillin (75.4%), amoxicillin ...BrowseSubjectAreas?ClickthroughthePLOStaxonomytofindarticlesinyourfield.FormoreinformationaboutPLOSSubjectAreas,clickhere.ArticleAuthorsMetricsCommentsMediaCoverageReaderComments(0)FiguresFiguresAbstractBackgroundExtendedspectrumBeta-lactamases(ESBLs)andAmpCbeta-lactamases(AmpC)arethecommonenzymesproducedbygramnegativebacilli,whicharetheirmainmechanismsofresistancetoallgenerationsofcephalosporins.Hence,thisstudyaimedtodeterminethemagnitudeofESBLsandAmpCproducinggramnegativebacilli(GNB)isolatedfromclinicalspecimensatInternationalclinicalLaboratoriesinAddisAbaba,Ethiopia.MethodsAcrosssectionalstudywasconductedfromJanuarytoMay2018.Fromdifferentclinicalspecimens,338GNBwereisolatedandcharacterized.Bacterialspeciesidentification,antimicrobialsusceptibilitytestingandscreeningforESBLsandAmpCproductionwereperformedusingPhoenixautomatedsystem(BDphoenix100).ESBLsproductionwasconfirmedusingacombinationdiscmethod.AllCefoxitinresistantandconfirmedESBLsproducingGNBwereconfirmedforAmpCbeta-lactamasesproductionbyAmpCconfirmatoryNeo-Sensitabsdiscs(ROSCOtablet).DatawereanalyzedusingSPSSversion20software.ResultsE.coli66.0%(224/338)followedbyK.pneumoniae12.1%(41/338)wereGNBmostfrequentlyisolated.TheoverallmagnitudeofESBLsproducingGNBwas38.8%(131/338)andtheextentofAmpCbeta-lactamaseproducingGNBwas2.4%(8/338).MajorityofESBLsandAmpCbeta-lactamasesproducingGNBwereisolatedfromurinespecimens47.5%(116/338).Ampicillin(75.4%),amoxicillinwithclavulanicacid(64.0%)andsulfamethoxazole-trimethoprim(55.6%)weremosttheantibioticstowhichresistancewasmostcommonlyfound.Themultidrugresistance(MDR)levelofGNBwas74.0%(250/338).OfESBLsandAmpCbeta-lactamasesproducingGNB,99.3%wereMDR(p<0.05).ConclusionThehighmagnitudeofESBLsandAmpCbeta-lactamasesproducingGNBcallstheneedsofstronginterventiontominimizefurtheroccurrenceandspreadofsuchGNB.Moreimportantly,theMDRlevelwashighwhi