{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T17:49:31Z","timestamp":1775152171780,"version":"3.50.1"},"reference-count":45,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2009,4,7]],"date-time":"2009-04-07T00:00:00Z","timestamp":1239062400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The purpose of this study was to investigate the presence of \u03b2-lactam-resistant bacteria in six different types of Portuguese cheese. The numbers of ampicillin resistant (AMPr) bacteria varied from 4.7 x 102 to 1.5 x 107 CFU\/g. Within 172 randomly selected \u03b2-lactam-resistant bacteria, 44 resistant phenotypes were found and 31.4% were multidrug resistant. The majority (85%) of the isolates identified belonged to the Enterobacteriaceae family. The presence of the blaTEM gene was detected in 80.9% of the tested isolates. The results suggest that without thermal processing of the milk and good hygienic practices, cheese may act as a vehicle of transfer of \u03b2-lactam-resistant bacteria to the gastrointestinaltract of consumers.<\/jats:p>","DOI":"10.3390\/ijms10041538","type":"journal-article","created":{"date-parts":[[2009,4,7]],"date-time":"2009-04-07T08:10:49Z","timestamp":1239091849000},"page":"1538-1551","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Resistance to \u03b2-lactams in Bacteria Isolated from Different Types of Portuguese Cheese"],"prefix":"10.3390","volume":"10","author":[{"given":"Paula","family":"Amador","sequence":"first","affiliation":[{"name":"Laborat\u00f3rio de Microbiologia, CBAA\/DBEB, Instituto Superior de Agronomia, Technical University of Lisbon, Tapada da Ajuda 1349-017 Lisbon, Portugal"},{"name":"Ci\u00eancias Qu\u00edmicas e das Biomol\u00e9culas, Escola Superior de Tecnologia de Sa\u00fade do Porto, Instituto Polit\u00e9cnico do Porto, Pra\u00e7a do Coronel Pacheco, No. 15, 4050-453 Porto, Portugal"},{"name":"Ci\u00eancias Exactas e do Ambiente, Sector de Biologia e Ecologia, Escola Superior Agr\u00e1ria, Instituto Polit\u00e9cnico de Coimbra, Bencanta, 3040-316 Coimbra, Portugal"}]},{"given":"Ruben","family":"Fernandes","sequence":"additional","affiliation":[{"name":"Ci\u00eancias Qu\u00edmicas e das Biomol\u00e9culas, Escola Superior de Tecnologia de Sa\u00fade do Porto, Instituto Polit\u00e9cnico do Porto, Pra\u00e7a do Coronel Pacheco, No. 15, 4050-453 Porto, Portugal"}]},{"given":"Cristina","family":"Prud\u00eancio","sequence":"additional","affiliation":[{"name":"Ci\u00eancias Qu\u00edmicas e das Biomol\u00e9culas, Escola Superior de Tecnologia de Sa\u00fade do Porto, Instituto Polit\u00e9cnico do Porto, Pra\u00e7a do Coronel Pacheco, No. 15, 4050-453 Porto, Portugal"}]},{"given":"Lu\u00edsa","family":"Brito","sequence":"additional","affiliation":[{"name":"Laborat\u00f3rio de Microbiologia, CBAA\/DBEB, Instituto Superior de Agronomia, Technical University of Lisbon, Tapada da Ajuda 1349-017 Lisbon, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2009,4,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1016\/j.vetmic.2007.01.015","article-title":"\u03b2-lactam resistance and \u03b2-lactamases in bacteria of animal origin","volume":"121","author":"Li","year":"2007","journal-title":"Vet. Microbiol"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1146\/annurev.publhealth.29.020907.090904","article-title":"Industrial Food Animal Production, Antimicrobial Resistance and Human Health","volume":"29","author":"Silbergeld","year":"2008","journal-title":"Ann. Rev. Public Health"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1040","DOI":"10.1086\/428451","article-title":"Antimicrobial-resistant and extra intestinal pathogenic Escherichia coli in retail foods","volume":"191","author":"Johnson","year":"2005","journal-title":"J. Infect. Dis"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Blackburn, CW (2006). Food Spoilage Microorganisms, CRC Press LLC.","DOI":"10.1201\/9781439824573"},{"key":"ref_5","unstructured":"Prud\u00eancio, C (2000). Multidrug resistance in yeast, University of Minho."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1002\/(SICI)1097-0320(20000101)39:1<26::AID-CYTO5>3.0.CO;2-C","article-title":"Rapid detection of efflux pumps and their relation with drug-resistance in yeast cells","volume":"39","author":"Sansonetty","year":"2000","journal-title":"Cytometry"},{"key":"ref_7","first-page":"775","article-title":"Molecular mechanisms that confer antibacterial drug resistance","volume":"406","author":"Walsh","year":"2000","journal-title":"Rev. Nature"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Lewis, K, Salyers, AA, Taber, HW, and Wax, RG (2000). Bacterial Resistance to Antimicrobials, Marcel Decker.","DOI":"10.1201\/9780824744939"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1209","DOI":"10.1136\/bmj.327.7425.1209","article-title":"Recent developments in \u03b2-lactamases and extended-spectrum \u03b2-lactamases","volume":"327","author":"Araj","year":"2003","journal-title":"BMJ"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2013","DOI":"10.1128\/AAC.41.9.2013","article-title":"Penicillin-binding proteins and induction of AmpC beta-lactamase","volume":"36","author":"Sanders","year":"1997","journal-title":"Antimicrob. Agents Chemother"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"533","DOI":"10.1128\/AAC.48.2.533-537.2004","article-title":"Epidemiology of conjugative plasmid-mediated AmpC beta-lactamases in the United States","volume":"48","author":"Alvarez","year":"2004","journal-title":"Antimicrob. Agents Chemother"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1128\/AAC.46.1.1-11.2002","article-title":"Plasmid-determined AmpC-type \u03b2-lactamases","volume":"46","author":"Philippon","year":"2002","journal-title":"Antimicrob. Agents Chemother"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1093\/jac\/dkl211","article-title":"Extended-spectrum \u03b2-lactamase-producing Enterobacteriaceae in different environments (humans, food, animal farms and sewage)","volume":"58","author":"Mesa","year":"2006","journal-title":"J. Antimicrob. Chemother"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"933","DOI":"10.1128\/CMR.14.4.933-951.2001","article-title":"Extended-spectrum \u03b2-lactamases in the 21st century: Characterization, epidemiology, and detection of this important resistance threat","volume":"14","author":"Bradford","year":"2001","journal-title":"Clin. Microbiol. Rev"},{"key":"ref_15","unstructured":"Jorgensen, JH (2003). Methods for dilution antimicrobial susceptibility test for bacteria that grow aerobically, Clinical and Laboratory Standards Institute. [6th]."},{"key":"ref_16","unstructured":"(2005). Performance standard for antimicrobial susceptibility testing, Clinical and Laboratory Standards Institute."},{"key":"ref_17","unstructured":"Holt, JG (1994). Bergey\u2019s Manual of Determinative Bacteriology, Lippincott Williams & Wilkins."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1128\/jb.66.1.24-26.1953","article-title":"The taxonomic significance of fermentative versus oxidative metabolism of carbohydrates by various Gram negative bacteria","volume":"66","author":"Hugh","year":"1953","journal-title":"J. Bacteriol"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1400","DOI":"10.1111\/j.1600-0463.2007.00722.x","article-title":"Multiplex PCR amplification assay for the detection of blaSHV, blaTEM and blaCTX-M genes in Enterobacteriaceae.","volume":"115","author":"Monstein","year":"2007","journal-title":"Apmis"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1111\/j.1472-765X.1989.tb00262.x","article-title":"Rapid extraction of bacterial genomic DNA with guanidium thiocyanate","volume":"8","author":"Pitcher","year":"1989","journal-title":"Lett. Appl. Microbiol"},{"key":"ref_21","unstructured":"(2007). Commission Regulation (EC 1441\/2007). Official J. Eur. Commun, L322, 12\u201329."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"410","DOI":"10.1046\/j.1472-765X.2003.01422.x","article-title":"Caseinolysis in cheese by Enterobacteriaceae strains of dairy origin","volume":"37","author":"Morales","year":"2003","journal-title":"Lett. Appl. Microbiol"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1093\/jac\/dkl183","article-title":"esac project group. European Surveillance of Antimicrobial Consumption (ESAC): Outpatient quinolone use in Europe","volume":"58","author":"Ferech","year":"2006","journal-title":"J. Antimicrob. Chemother"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"408","DOI":"10.1093\/jac\/dkl186","article-title":"esac project group. European Surveillance of Antimicrobial Consumption (ESAC): Outpatient penicillin use in Europe","volume":"58","author":"Ferech","year":"2006","journal-title":"J. Antimicrob. Chemother"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"413","DOI":"10.1093\/jac\/dkl185","article-title":"esac project group. European Surveillance of Antimicrobial Consumption (ESAC): outpatient cephalosporin use in Europe","volume":"58","author":"Coenen","year":"2006","journal-title":"J. Antimicrob. Chemother"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"289","DOI":"10.1089\/mdr.2007.746","article-title":"Tetracycline consumption and occurrence of tetracycline resistance in Salmonella Typhimurium phage types from danish pigs","volume":"13","author":"Emborg","year":"2007","journal-title":"Microb. Drug Res"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1016\/j.fm.2007.07.008","article-title":"Isolation and characterization of tetracycline-resistant Citrobacter spp. from catfish","volume":"25","author":"Nawaz","year":"2008","journal-title":"Food Microbiol"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1016\/S0378-1135(98)00234-X","article-title":"Tetracycline resistance in Staphylococcus spp. from domestic animals","volume":"63","author":"Schwarz","year":"1998","journal-title":"Vet. Microbiol"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"348","DOI":"10.1016\/j.ijantimicag.2006.11.015","article-title":"Widespread distribution of tetracycline resistance genes in a confined animal feeding facility","volume":"29","author":"Stine","year":"2007","journal-title":"Int. J. Antimicrob. Agents"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"816","DOI":"10.1128\/AAC.49.2.816-819.2005","article-title":"Antibiotic resistance in diarrheagenic Escherichia coli and Shigella strains isolated from children in Hanoi, Vietnam","volume":"49","author":"Nguyen","year":"2005","journal-title":"Antimicrob. Agents Chemother"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1093\/jac\/46.2.223","article-title":"Increasing resistance to fluoroquinolones in Escherichia coli from urinary tract infections in the Netherlands","volume":"46","author":"Goettsch","year":"2000","journal-title":"J. Antimicrob. Chemother"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.jhin.2008.05.007","article-title":"Bloodstream infections caused by multidrug-resistant Enterobacteriaceae: report from two Portuguese hospitals","volume":"70","author":"Fernandes","year":"2008","journal-title":"J. Hosp. Infect"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1093\/jac\/dkl483","article-title":"CTX-M: changing the face of ESBLs in Europe","volume":"59","author":"Livermore","year":"2007","journal-title":"J. Antimicrob. Chemother"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"588","DOI":"10.1111\/j.1472-765X.2007.02133.x","article-title":"Serotyping, PCR, phage-typing and antibiotic sensitivity testing of Salmonella serovars isolated from urban drinking water supply systems of Nepal","volume":"44","author":"Bhatta","year":"2007","journal-title":"Lett. Appl. Microbiol"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1128\/AEM.01254-08","article-title":"Quantifying nonspecific TEM beta-lactamase (blaTEM) genes in a wastewater stream","volume":"75","author":"Lachmayr","year":"2009","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1093\/jac\/dkn445","article-title":"Escherichia coli of animal origin in Norway contains a blaTEM-20-carrying plasmid closely related to blaTEM-20 and blaTEM-52 plasmids from other European countries","volume":"63","author":"Sunde","year":"2009","journal-title":"J. Antimicrob. Chemother"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1408","DOI":"10.4315\/0362-028X-68.7.1408","article-title":"Molecular characterization of multidrug-resistant Proteus mirabilis isolates from retail meat products","volume":"68","author":"Kim","year":"2005","journal-title":"J. Food Prot"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"4785","DOI":"10.1128\/AEM.00252-07","article-title":"Impact of three ampicillin dosage regimens on selection of ampicillin resistance in Enterobacteriaceae and excretion of blaTEM genes in swine feces","volume":"73","author":"Bibbal","year":"2007","journal-title":"Appl. Environ. Microbiol"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1872","DOI":"10.1128\/AAC.01514-06","article-title":"Dissemination of an extended-spectrum-beta-lactamase blaTEM-52 gene-carrying IncI1 plasmid in various Salmonella enterica serovars isolated from poultry and humans in Belgium and France between 2001 and 2005","volume":"51","author":"Cloeckaert","year":"2007","journal-title":"Antimicrob. Agents Chemother"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"3957","DOI":"10.1073\/pnas.0800072105","article-title":"Antibiotic-resistant soil bacteria in transgenic plant fields","volume":"105","author":"Sanguin","year":"2008","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1267","DOI":"10.1128\/AAC.49.3.1267-1268.2005","article-title":"Evolution of transposons containing blaTEM genes","volume":"49","author":"Partridge","year":"2005","journal-title":"Antimicrob. Agents Chemother"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"196","DOI":"10.1016\/j.fm.2007.09.004","article-title":"Antibiotic resistance genes and identification of staphylococci collected from the production chain of swine meat commodities","volume":"25","author":"Simeoni","year":"2008","journal-title":"Food Microbiol"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"374","DOI":"10.1111\/j.1439-0450.2004.00789.x","article-title":"Evidence of an association between use of antimicrobial agents in food animals and antimicrobial resistance among bacteria isolated from humans and the human health consequences of such resistance","volume":"51","author":"Angulo","year":"2004","journal-title":"J. Vet. Med. B"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1093\/jac\/dkg483","article-title":"Does the use of antibiotics in food animals pose a risk to human health? A critical review of published data","volume":"53","author":"Phillips","year":"2004","journal-title":"J. Antimicrob. Chemother"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"579","DOI":"10.1016\/S0140-6736(05)17907-0","article-title":"ESAC Project Group. Outpatient antibiotic use in Europe and association with resistance: a cross-national database study","volume":"365","author":"Goossens","year":"2005","journal-title":"Lancet"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/10\/4\/1538\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T22:10:10Z","timestamp":1760220610000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/10\/4\/1538"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2009,4,7]]},"references-count":45,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2009,4]]}},"alternative-id":["i10041538"],"URL":"https:\/\/doi.org\/10.3390\/ijms10041538","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2009,4,7]]}}}