Ceftazidime-Avibactam Activity Tested against Enterobacteriaceae Isolates from U.S. Hospitals (2011 to 2013) and Characterization of β-Lactamase-Producing Strains

ABSTRACTCeftazidime-avibactam (MIC50/90, 0.12/0.25 μg/ml) inhibited 99.9% (20,698/20,709) ofEnterobacteriaceaeisolates at ≤8 μg/ml. This compound was active against resistant subsets, including ceftazidime-nonsusceptibleEnterobacter cloacae(MIC50/90, 0.25/0.5 μg/ml) and extended-spectrum β-lactamase (ESBL) phenotype isolates. An ESBL phenotype was noted among 12.4% (1,696/13,692 isolates from targeted species) of the isolates, including 776Escherichia coli(12.0% for this species; MIC50/90, 0.12/0.25 μg/ml), 721Klebsiella pneumoniae(16.3%; MIC50/90, 0.12/0.25 μg/ml), 119Klebsiella oxytoca(10.3%; MIC50/90, 0.06/0.25 μg/ml), and 80Proteus mirabilis(4.9%; MIC50/90, 0.06/0.12 μg/ml) isolates. The most common enzymes detected among ESBL phenotype isolates from 2013 (n= 743) screened using a microarray-based assay were CTX-M-15-like (n= 307), KPC (n= 120), SHV ESBLs (n= 118), and CTX-M-14-like (n= 110). KPC producers were highly resistant to comparators, and ceftazidime-avibactam (MIC50/90, 0.5/2 μg/ml) and tigecycline (MIC50/90, 0.5/1 μg/ml; 98.3% susceptible) were the most active agents against these strains. Meropenem (MIC50/90, ≤0.06/≤0.06 μg/ml) and ceftazidime-avibactam (MIC50/90, 0.12/0.25 μg/ml) were active against CTX-M-producing isolates. Other enzymes were also observed, and ceftazidime-avibactam displayed good activity against the isolates producing less common enzymes. Among 11 isolates displaying ceftazidime-avibactam MIC values of >8 μg/ml, three wereK. pneumoniaestrains producing metallo-β-lactamases (all ceftazidime-avibactam MICs, >32 μg/ml), with two NDM-1 producers and oneK. pneumoniaestrain carrying theblaKPC-2andblaVIM-4genes. Therapeutic options for isolates producing β-lactamases may be limited, and ceftazidime-avibactam, which displayed good activity against strains, including those producing KPC enzymes, merits further study in infections where such organisms occur.

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In Vitro Activity of Imipenem against Carbapenemase-Positive Enterobacteriaceae Isolates Collected by the SMART Global Surveillance Program from 2008 to 2014

Journal of Clinical Microbiology ◽

10.1128/jcm.02316-16 ◽

2017 ◽

Vol 55 (6) ◽

pp. 1638-1649 ◽

Cited By ~ 30

Author(s):

James A. Karlowsky ◽

Sibylle H. Lob ◽

Krystyna M. Kazmierczak ◽

Robert E. Badal ◽

Katherine Young ◽

...

Keyword(s):

Escherichia Coli ◽

Klebsiella Pneumoniae ◽

Klebsiella Oxytoca ◽

Enterobacter Cloacae ◽

Surveillance Program ◽

In Vitro Activity ◽

Content Type ◽

Carbapenemase Gene ◽

Check Points

ABSTRACT The Study for Monitoring Antimicrobial Resistance Trends (SMART) global surveillance program collected 103,960 isolates of Enterobacteriaceae from 2008 to 2014. From this isolate collection, all ertapenem-nonsusceptible isolates (MIC, ≥1 μg/ml; n = 3,428) and 9,371 isolates of Escherichia coli , Klebsiella pneumoniae , Klebsiella oxytoca , and Proteus mirabilis with an ertapenem-susceptible extended-spectrum-β-lactamase (ESBL)-positive phenotype were assessed for the presence of common carbapenemase genes using a Check-MDR CT101 microarray (Check-Points, Wageningen, the Netherlands) and published multiplex PCR assays. Testing identified 1,493 isolates that harbored a carbapenemase gene (1,485 ertapenem-nonsusceptible isolates and 8 ertapenem-susceptible ESBL-positive isolates) and accounted for 1.4% (1,493/103,960) of all isolates of Enterobacteriaceae . The most frequently identified carbapenemase genes were the KPC ( n = 794), OXA-48-like ( n = 300), and NDM ( n = 290) genes. Carbapenemase genes were most frequently identified in Klebsiella pneumoniae ( n = 1,127), Escherichia coli ( n = 149), and Enterobacter cloacae ( n = 110). Among the carbapenemase-positive isolates, 66.7% (2/3), 37.0% (111/300), 20.0% (8/40), 3.3% (3/92), 2.3% (18/794), and 0% (0/290) of the isolates with genes for GES, OXA-48-like, IMP, VIM, KPC, and NDM, respectively, were susceptible to imipenem (MIC, ≤1 μg/ml). Isolates that tested as susceptible to imipenem were not uncommon among carbapenemase-positive isolates (9.4%, 141/1,493) and most frequently carried OXA-48-like enzymes (78.7%; 111/141); however, overall, these isolates remained rare (0.1%, 141/103,960). The practice of screening clinical isolates of Enterobacteriaceae that test as susceptible to carbapenems in vitro for the presence of carbapenemase genes remains controversial and requires further study.

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Caracterización de la infección urinaria y resistencia antimicrobiana en receptores de trasplante renal de un centro colombiano

Revista Urología Colombiana / Colombian Urology Journal ◽

10.1055/s-0041-1730360 ◽

2021 ◽

Vol 30 (03) ◽

pp. e165-e170

Author(s):

David Andrés Castañeda-Millán ◽

Juan Carlos Osorio-Iriarte ◽

Juan Pablo Alzate-Granados ◽

Daniel Amórtegui-Rodríguez ◽

Juan Sebastián Arbeláez-Teuzaba ◽

...

Keyword(s):

Diabetes Mellitus ◽

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Klebsiella Pneumoniae ◽

Serratia Marcescens ◽

Proteus Mirabilis ◽

Klebsiella Oxytoca ◽

Enterobacter Cloacae ◽

Salmonella Spp

ResumenLa infección del tracto urinario (ITU) es una de las principales complicaciones postrasplante renal, los datos a nivel nacional en ese grupo poblacional son limitados. Objetivos caracterizar la microbiología de las ITU presentadas en receptores de trasplante renal (TxR) en un centro colombiano durante el periodo 2017–2019, los factores relacionados con la resistencia antimicrobiana y el impacto de la ITU en la función del injerto renal. Métodos estudio de corte transversal ejecutado mediante el análisis de la base de datos de ingresos hospitalarios por urgencias de pacientes receptores de TxR con sospecha clínica de ITU en una institución de cuarto nivel en Bogotá, Colombia. El análisis de datos se ejecutó en STATA 13.0. Resultados La ITU causó 12,69% de visitas a urgencias en pacientes trasplantados. Los microorganismos aislados fueron: Escherichia coli 52,22%, Klebsiella pneumoniae 16,67%, Pseudomonas aeruginosa 4,44%, Salmonella spp 4,44%, Proteus mirabilis 3,33%, Serratia marcescens 2,22%, Klebsiella oxytoca 2,22%, Citrobacter koseri 1,11%, Enterobacter cloacae 1,11%, otros 2,22%; El urocultivo fue negativo en 10% de los casos. El 28,39% (n:23) de gérmenes aislados fue multisensible mientras que el 71,60% (n:58) expresó algún tipo de patrón de resistencia distribuido así: 68,96% productor de betalactamasa de espectro extendido (BLEE), 15,52% productor de carbapenemasas, 12,06% productor de betalactamasa tipo IRT, 3,45% fue catalogado como multirresistente. 17,78% de los pacientes presentó criterios de urosepsis, no se registró ningún caso de mortalidad asociada a la ITU. La creatinina sérica tuvo un incremento promedio de 0,46 mg/dl durante el episodio de ITU (p: <0,0001) y el antecedente de diabetes mellitus se relacionó con la ITU causada por gérmenes resistentes (p: 0,008). Conclusiones La ITU es una causa frecuente de atención en urgencias para pacientes receptores de TxR; la Escherichia coli es el microorganismo causal más frecuente y cerca del 70% de los gérmenes aislados presentó algún patrón de resistencia antimicrobiana.

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Predominance of KPC-3 in a Survey for Carbapenemase-Producing Enterobacteriaceae in Portugal

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05065-14 ◽

2015 ◽

Vol 59 (6) ◽

pp. 3588-3592 ◽

Cited By ~ 23

Author(s):

Vera Manageiro ◽

Eugénia Ferreira ◽

Joana Almeida ◽

Stephanie Barbosa ◽

Constança Simões ◽

...

Keyword(s):

Escherichia Coli ◽

Gene Transfer ◽

Klebsiella Pneumoniae ◽

Lateral Gene Transfer ◽

Klebsiella Oxytoca ◽

Enterobacter Aerogenes ◽

Enterobacter Cloacae ◽

Content Type ◽

Major Mechanism

ABSTRACTAmong the 2,105Enterobacteriaceaetested in a survey done in Portugal, 165 were nonsusceptible to carbapenems, from which 35 (26Klebsiella pneumoniae, 3Escherichia coli, 2Enterobacter aerogenes, and 3Enterobacter cloacaeisolates and 1Klebsiella oxytocaisolate) were confirmed to be carbapenemase producers by the presence of 30Tn4401d-blaKPC-3, 4intI3-blaGES-5, and oneintI1-blaVIM-2gene, alone or in combination with otherblagenes. The dissemination ofblaKPC-3gene carried by an IncF plasmid suggests lateral gene transfer as a major mechanism of dissemination.

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Антимікробна резистентність провідних збудників інфекцій сечових шляхів у Києві (Україна)

International Journal of Antibiotics and Probiotics ◽

10.31405/ijap.1-2.17.03 ◽

2017 ◽

Vol 1 (2) ◽

pp. 48-60

Author(s):

A.G. Salmanov ◽

A.V. Rudenko

Keyword(s):

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Klebsiella Pneumoniae ◽

Staphylococcus Epidermidis ◽

Klebsiella Oxytoca ◽

Enterobacter Aerogenes ◽

Enterobacter Cloacae ◽

Proteus Vulgaris ◽

Providencia Rettgeri ◽

E Coli

Мета роботи — вивчити резистентність до антибіотиків бактеріальних збудників інфекцій сечових шляхів (ІСШ), виділених у пацієнтів урологічного стаціонару в м. Києві. Матеріали і методи. Досліджено 1612 штамів бактерій, виділених із сечі хворих з ІСШ (цистит, уретрит, пієлонефрит), госпіталізованих в урологічне відділення ДУ «Інститут урології НАМН України» у м. Києві протягом 2016 р. Серед пацієнтів переважали жінки — 1201 (74,5 %). Вік хворих становив від 17 до 74 років. Для збору даних використано медичну документацію лікарні. Мікробіологічні дослідження виконано у лабораторії мікробіології ДУ «Інститут урології НАМН України». Аналізували результати культурального дослідження зразків сечі, зібраних за наявності клінічних ознак ІСШ. Дослідження клінічного матеріалу та інтерпретацію отриманих результатів проводили загальноприйнятими методами. Вивчено чутливість уропатогенів до 31 антибіотика дискодифузійним методом відповідно до рекомендацій Інституту клінічних та лабораторних стандартів США (Clinical and Laboratory Standards Institute (CLSI)). Результати та обговорення. Аналіз мікробного спектра сечі виявив домінування серед уропатогенів штамів Escherichia coli (32,0 %), Enterococcus faecalis (19,5 %), Klebsiella pneumoniae (10,9 %), Staphylococcus epidermidis (8,9 %), S. haemolyticus (6,5 %) та Pseudomonas aeruginosa (6,4 %). Частка Enterococcus faecium, Enterobacter aerogenes і Streptococcus viridans становила відповідно 2,5, 2,2 і 1,6 %, Enterobacter cloacae, Klebsiella oxytoca, Acinetobacter baumannii, Proteus vulgaris та Providencia rettgeri — менше 1,0 %. У більшості випадків (69,7 %) мікроорганізми виділено у монокультурі, у решті випадків — у мікробних асоціа- ціях. Високу резистентність до тестованих антибіотиків виявили штами E. aerogenes (45,1 %), E. cloacae (45,7 %), E. faecium (40,9 %), E. faecalis (40,7 %), E. coli (39,9 %), P. aeruginosa (34,0 %), K. pneumoniae (28,6 %). Найбільш активними до уропатогенів були іміпенем (E. coli — 87,6 %, P. aeruginosa — 75,7 %, E. cloacae — 67,3 %, E. aerogenes — 72,6 %, K. pneumoniae — 93,2 %), меропенем (E. coli — 89,1 %, P. aeruginosa — 76,7 %, K. pneumoniae — 82,6 %), лефлоцин (E. coli — 74,5 %, ентерококи — 78,7 %, P. aeruginosa — 76,7 %, E. cloacae — 73,9 %, E. aerogenes — 80,4 %, K. pneumoniae — 83,5 %), амоксицилін/клавуланат (ентерококи — 84,6 %), фурагін (ентерококи — 82,6 %), цефоперазон (K. pneumoniae — 89,2 %, P. aeruginosa — 73,8 %), цефтріаксон (K. pneumoniae — 80,1 %). Висновки. Антибіотикорезистентність збудників ІСШ — важлива терапевтична проблема. Найбільшою активністю до уропатогенів характеризуються іміпенем, меропенем, лефлоцин, амоксицилін/ клавуланат, фурагін, цефоперазон, цефтріаксон, які можна розглядати як препарат вибору для призначення стартової терапії ІСШ. Необхідно здійснювати постійний моніторинг за резистентністю до дії антибіотиків. Політику використання антибіотиків у кожному стаціонарі слід визначати залежно від локальних даних щодо резистентності до протимікробних препаратів.

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Comparison of the Superpolymyxin and ChromID Colistin R Screening Media for the Detection of Colistin-Resistant Enterobacteriaceae from Spiked Rectal Swabs

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01618-18 ◽

2018 ◽

Vol 63 (1) ◽

Cited By ~ 7

Author(s):

Delphine Girlich ◽

Thierry Naas ◽

Laurent Dortet

Keyword(s):

Escherichia Coli ◽

Klebsiella Pneumoniae ◽

Confidence Interval ◽

Enterobacter Cloacae ◽

Bacterial Isolates ◽

Colistin Resistance ◽

Gram Negative ◽

Content Type ◽

Rectal Swabs ◽

Stool Samples

ABSTRACT The dissemination of carbapenemase-producing Enterobacteriaceae (CPE) has led to the increased use of colistin, which has resulted in the emergence of colistin-resistant Enterobacteriaceae worldwide. One of the most threatening scenarios is the dissemination of colistin resistance in CPE, particularly the plasmid-encoded resistance element MCR. Thus, it has now become mandatory to possess reliable media to screen for colistin-resistant Gram-negative bacterial isolates, especially Enterobacteriaceae. In this study, we evaluated the performances of the Superpolymyxin medium (ELITechGroup) and the ChromID Colistin R medium (bioMérieux) to screen for colistin-resistant Enterobacteriaceae from spiked rectal swabs. Stool samples were spiked with a total of 94 enterobacterial isolates (Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Enterobacter cloacae), including 53 colistin-resistant isolates. ESwabs (Copan Diagnostics) were then inoculated with those spiked fecal suspensions, and culture proceeded as recommended by both manufacturers. The sensitivity of detection of colistin-resistant Enterobacteriaceae was 86.8% (95% confidence interval [95% CI] = 74.0% to 94.0%) using both the Superpolymyxin medium and the ChromID Colistin R plates. Surprisingly, the isolates that were not detected were not the same for both media. The specificities were high for both media, at 97.9% (95% CI = 87.3% to 99.9%) for the Superpolymyxin medium and 100% (95% CI = 90.4% to 100%) for the ChromID Colistin R medium. Both commercially available media, ChromID Colistin R and Superpolymyxin, provide useful tools to screen for colistin-resistant Enterobacteriaceae from patient samples (rectal swabs) regardless of the level and mechanism of colistin resistance.

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PERFIL DE SENSIBILIDADE A ANTIMICROBIANOS POR COMPONENTES DA MICROBIOTA BACTERIANA ORAL E RETAL DE PRIMATAS NÃO HUMANOS

Ciência Animal Brasileira ◽

10.1590/1089-6891v20e-47632 ◽

2019 ◽

Vol 20 ◽

Author(s):

Marcone Helmer Silva ◽

Hilma Lúcia Tavares Dias ◽

Ednaldo da Silva Filho ◽

Sarah Raphaela Rocha de Azevedo Scalercio ◽

Wellington Bandeira da Silva ◽

...

Keyword(s):

Escherichia Coli ◽

Klebsiella Pneumoniae ◽

Serratia Marcescens ◽

Proteus Mirabilis ◽

Enterobacter Cloacae ◽

Callithrix Jacchus ◽

E Coli ◽

Staphylococcus Xylosus

Resumo Os objetivos desta pesquisa foram identificar bactérias isoladas da cavidade oral e da ampola retal de Saimiri collinsi e Callithrix jacchus e determinar a sensibilidade a 16 antimicrobianos. Trinta indivíduos de cada espécie foram analisados e foram isoladas 136 bactérias em C. jacchus e 84 em S. collinsi. As bactérias isoladas em maior número em S. collinsi foram Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, Raoutella ornithinolytica, Staphylococcus xylosus e Proteus mirabilis. As bactérias isoladas em C. jacchus foram K. pneumoniae, E. cloacae, E. coli, Serratia marcescens e S. xylosus na cavidade oral e ampola retal. O teste de sensibilidade mostrou que, dentre as cepas isoladas, os maiores percentuais de resistência foram observados para ampicilina, amoxicilina, cefalotina e nitrofurantoína. Na cavidade oral de ambas as espécies as cepas foram sensíveis à ceftazidima, ceftriaxona, meropenem, amicacina, levofloxacina e a sulfametoxazol/trimetoprim. Na ampola retal, as isoladas foram sensíveis à cefoxitina, ceftazidima, ceftriaxona, ertapenem, meropenem, amicacina e levofloxacina. Conclui-se que as espécies de S. collinsi e C. jacchus apresentam sua microbiota oral e retal composta por várias espécies bacterianas e que a resistência pode ser um problema no criatório, uma vez que as cepas mostraram percentuais elevados de resistência a diferentes antimicrobianos.

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Characterization of SXT/R391 Integrative and Conjugative Elements in Proteus mirabilis Isolates from Food-Producing Animals in China

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02852-15 ◽

2016 ◽

Vol 60 (3) ◽

pp. 1935-1938 ◽

Cited By ~ 25

Author(s):

Chang-Wei Lei ◽

An-Yun Zhang ◽

Hong-Ning Wang ◽

Bi-Hui Liu ◽

Li-Qin Yang ◽

...

Keyword(s):

Escherichia Coli ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Resistance Genes ◽

Proteus Mirabilis ◽

Whole Genome ◽

Content Type ◽

Integrative And Conjugative Elements ◽

Animal Farms

SXT/R391 integrative and conjugative elements (ICEs) were detected in 8 out of 125Proteus mirabilisisolates from food-producing animals in China. Whole-genome sequencing revealed that seven ICEs were identical to ICEPmiJpn1, carrying the cephalosporinase geneblaCMY-2. Another one, designated ICEPmiChn1, carried five resistance genes. All eight ICEs could be transferred toEscherichia colivia conjugation. The results highlight the idea that animal farms are important reservoir of the SXT/R391 ICE-containingP. mirabilis.

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Profil Penggunaan Antibiotik dan Peta Kuman pada Pasien Gangren Diabetes Melitus di Sebuah RSUD di Kabupaten Gresik

Media Pharmaceutica Indonesiana (MPI) ◽

10.24123/mpi.v3i2.2966 ◽

2020 ◽

Vol 3 (2) ◽

pp. 96

Author(s):

Isna Romadhona ◽

Fauna Herawati ◽

Rika Yulia

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Pseudomonas Aeruginosa ◽

Klebsiella Pneumoniae ◽

Acinetobacter Baumannii ◽

Proteus Mirabilis ◽

Enterobacter Aerogenes ◽

Enterobacter Cloacae ◽

Proteus Vulgaris ◽

Diabetes Melitus

Antibiotik merupakan obat yang digunakan untuk mengatasi dan mencegah infeksi bakteri. Penggunaan antibiotik yang tidak tepat dapat menimbulkan berbagai masalah, diantaranya pengobatan akan lebih mahal dan juga risiko terjadinya resistensi bakteri terhadap antibiotik. Penelitian ini bertujuan untuk mengetahui profil penggunaan antibiotik dan profil peta kuman pada pasien gangren diabetes melitus di sebuah RSUD di Kabupaten Gresik serta untuk mengetahui kesesuaian penggunaan antibiotik dengan mengacu pada Permenkes Republik Indonesia No. 2406/Menkes/PER/XII/2011. Data penggunaan antibiotik diperoleh dari catatan Rekam Medis pada periode Januari – November 2017. Data penggunaan antibiotik dihitung dengan menggunakan rumus DDD/100 pasien-hari rawat. Hasil perhitungan DDD/100 pasien-hari rawat menunjukkan hasil sebesar 470,11 DDD/100 pasien-hari rawat. Peta kuman pada pasien gangren, melaporkan adanya bakteri Enterobacter cloacae 24%, Escherichia coli 18%, Staphylococcus aureus 15%, Acinetobacter baumannii 9%, Pseudomonas aeruginosa 6%, Citrobacter youngae 6%, Enterobacter aerogenes 6%, Proteus vulgaris 6%, Staphylococcus schleiferi 6%, Klebsiella pneumoniae 3%, dan Proteus mirabilis 3% . Penggunaan antibiotik seftriakson dan metronidazol pada pasien gangren diabetes melitus di sebuah RSUD di Kabupaten Gresik pada periode Januari – November 2017 telah sesuai dengan pedoman penggunaan antibiotik berdasarkan Permenkes Republik Indonesia No. 2406/Menkes/PER/ XII/2011, yaitu antibiotik golongan sefalosporin generasi III yang lebih aktif terhadap Enterobacteriaceae dan antibiotik golongan nitroimidazol yang dapat mengobati infeksi bakteri basil anerob Gram-Negatif.

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Extended-Spectrum Beta-Lactamase Testing for Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis

Clinical Microbiology Procedures Handbook ◽

10.1128/9781555818814.ch5.12 ◽

2016 ◽

pp. 5.12.1-5.12.7

Keyword(s):

Escherichia Coli ◽

Klebsiella Pneumoniae ◽

Proteus Mirabilis ◽

Klebsiella Oxytoca ◽

Beta Lactamase ◽

Extended Spectrum Beta Lactamase ◽

Extended Spectrum

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Detection and Molecular Characterization of Escherichia coli CTX-M-15 and Klebsiella pneumoniae SHV-12 β-Lactamases from Bovine Mastitis Isolates in the United Kingdom

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00752-13 ◽

2013 ◽

Vol 58 (2) ◽

pp. 789-794 ◽

Cited By ~ 53

Author(s):

Dorina Timofte ◽

Iuliana E. Maciuca ◽

Nicholas J. Evans ◽

Helen Williams ◽

Andrew Wattret ◽

...

Keyword(s):

Escherichia Coli ◽

United Kingdom ◽

Klebsiella Pneumoniae ◽

Bovine Mastitis ◽

Conjugative Plasmid ◽

Sensitivity Testing ◽

Content Type ◽

E Coli ◽

The United Kingdom

ABSTRACTRecent reports raised concerns about the role that farm stock may play in the dissemination of extended-spectrum β-lactamase (ESBL)-producing bacteria. This study characterized the ESBLs in twoEscherichia coliand threeKlebsiella pneumoniaesubsp.pneumoniaeisolates from cases of clinical bovine mastitis in the United Kingdom. Bacterial culture and sensitivity testing of bovine mastitic milk samples identified Gram-negative cefpodoxime-resistant isolates, which were assessed for their ESBL phenotypes. Conjugation experiments and PCR-based replicon typing (PBRT) were used for characterization of transferable plasmids.E. coliisolates belonged to sequence type 88 (ST88; determined by multilocus sequence typing) and carriedblaCTX-M-15andblaTEM-1, whileK. pneumoniaesubsp.pneumoniaeisolates carriedblaSHV-12andblaTEM-1. Conjugation experiments demonstrated thatblaCTX-M-15andblaTEM-1were carried on a conjugative plasmid inE. coli, and PBRT identified this to be an IncI1 plasmid. The resistance genes were nontransferable inK. pneumoniaesubsp.pneumoniaeisolates. Moreover, in theE. coliisolates, an association of ISEcp1 and IS26withblaCTX-M-15was found where the IS26element was inserted upstream of both ISEcp1and theblaCTX-Mpromoter, a genetic arrangement highly similar to that described in some United Kingdom human isolates. We report the first cases in Europe of bovine mastitis due toE. coliCTX-M-15 and also of bovine mastitis due toK. pneumoniaesubsp.pneumoniaeSHV-12 β-lactamases in the United Kingdom. We also describe the genetic environment ofblaCTX-M-15and highlight the role that IncI1 plasmids may play in the spread and dissemination of ESBL genes, which have been described in both human and cattle isolates.

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