Extended-spectrum β-lactamases, transferable quinolone resistance, and virulotyping in extra-intestinal E. coli in Uruguay

Introduction: To characterize extended-spectrum β-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR) genes in Escherichia coli isolates obtained from extra-intestinal samples in three Uruguayan hospitals. Methodology: Fifty-five ESBL-producing E. coli isolates were studied. Virulence genes, ESBLs, and PMQR genes were detected by polymerase chain reaction. ESBL-producing isolates were compared by pulsed-field gel electrophoresis. Multi-locus sequence typing was also performed on 13 selected isolates. Results: Thirty-seven isolates harbored blaCTX-M-15 (67.3%), eight blaCTX-M-2 (14.6%), five blaCTX-M-14 (9.1%), three carried both blaCTX-M-2 and blaCTX-M-14, one blaCTX-M-9, and one blaCTX-M-8. Among the CTX-M-15 producers, 92% belonged to sequence types ST131 and ST405, and carried aac(6’)Ib-cr as well. Isolates harboring blaCTX-M-2, blaCTX-M-14, blaCTX-M-9, or blaCTX-M-8 were found to be genetically unrelated. Conclusions: The successful dissemination of CTX-M-15-producing E.coli isolates seems to be linked to the spreading of high-risk clones and horizontal gene transfer. A trade-off between carrying more antibiotic resistance and less virulence-related genes could partially account for the evolutionary advantages featured by successful clones.Fil: Vignoli, Rafael. Universidad de la República; UruguayFil: García Fulgueiras, Virginia. Universidad de la República; UruguayFil: Cordeiro, Nicolás F.. Universidad de la República; UruguayFil: Bado, Inés. Universidad de la República; UruguayFil: Seija, Verónica. Universidad de la República; Uruguay. Hospital Pasteur de Montevideo; UruguayFil: Aguerrebere, Paula. Universidad de la República; UruguayFil: Laguna, Gabriel. Universidad de la República; UruguayFil: Araújo, Lucía. Universidad de la República; UruguayFil: Bazet, Cristina. Universidad de la República; UruguayFil: Gutkind, Gabriel Osvaldo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Chabalgoity Rodríguez, José Alejandro. Universidad de la República; Urugua

Prevalence and characterization of hybrid blaCTX-M among Escherichia coli isolates from livestock and other animals

This study investigated 248 extended-spectrum β-lactamase-producing Escherichia coli isolates from 2012 to 2013 for hybrid blaCTX-M genes. blaCTX-M genes were detected in 228 isolates of which 14 isolates were hybrid blaCTX-M positive (6 blaCTX-M-123, 6 blaCTX-M-64, and 2 blaCTX-M-132). The 14 hybrid blaCTX-M–carrying isolates (8 from chickens, 2 each from pigs and cattle, 1 each from dog and rodent) were genetically diverse. All but 2 hybrid blaCTX-M were carried on IncI1 (5 blaCTX-M-123) and IncI2 (6 blaCTX-M-64 and one blaCTX-M-132) plasmids. Our IncI1 and IncI2 plasmids had pHNAH4-1–like and pHN1122-1–like restriction fragment length polymorphism patterns, respectively. Genetic relatedness of the plasmids to pHNAH4-1 and pHN1122-1 were confirmed by complete sequencing of 3 plasmids, pCTXM123_C0996, pCTXM64_C0967, and pCTXM132_P0421. Plasmids closely related to pHNAH4-1 and pHN1122-1 and carrying different blaCTX-M alleles have been reported from multiple geographic areas in China previously. The findings highlighted the wide dissemination of hybrid blaCTX-M variants in different parts of China.postprin

Multiple ambler class A ESBL genes among Klebsiella pneumoniae isolates in a Malaysian district hospital

Detailed reports regarding the distribution and activity of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae isolates are currently not widely available in the Malaysian setting. This study was conducted to determine the ESBL genes distribution rate, phenotypic detection, and antimicrobial susceptibility patterns among beta-lactam resistant Klebsiella pneumoniae isolated from a Malaysian district hospital. K. pneumoniae isolates were collected from a microbiology laboratory at Hospital Pakar Sultanah Fatimah, Malaysia. Following exclusion and inclusion criteria, 141 isolates were selected for this study. K. pneumoniae was identified by phenotypic method, whilst antibiotics' susceptibility patterns were determined by the Kirby-Bauer method, as described in Clinical Laboratory Standard Institute (CLSI) guidelines (Oxoid, UK; Becton-Dickenson, USA). Detection of Ambler Group A ESBL gene (blaSHV, blaTEM, blaCTX-M-1, blaCTX-M-2, blaCTX-M-8, blaCTX-M-9, and blaCTX-M-25) was done using polymerase chain reaction (PCR). ESBL genes were found in 85.8% of K. pneumoniae (121 of 141) isolates. Only blaSHV, blaTEM, blaCTX-M-1, and blaCTX-M-9 were detected among K. pneumoniae isolates with distribution rates of 75.2% (106 of 141), 41.1% (58 of 141), 44% (62 of 141), and 0.7% (1 of 141), respectively. There was no blaCTX-M-2, blaCTX-M-8, or blaCTX-M-25 detected from any isolates in this study. Sequencing of representative amplicons revealed blaSHV as SHV-12, blaTEM as TEM-1, blaCTX-M-1 as CTX-M-15, and blaCTX-M-9 as CTX-M-18. The phenotypic detection rate of ESBL was 71.6% (101 of 141), whilst 9.2% (13 of 141) were positive for carbapenemase. AmpC beta-lactamase was detected in 22% (31 of 141) of all isolates. Antibiotic resistance was between 44.6% (netilmicin) and 97.2% (cefotaxime). Based on ESBL genes distribution, blaSHV was a predominant gene found in one of Malaysian district hospitals, notwithstanding having blaTEM, blaCTX-M-1, and blaCTX-M-9. Despite carrying multiple ESBL genes, some strains were positive for carbapenemase or AmpC beta-lactamase, which resulted in high antimicrobial resistance rates

Chromosomal integration of blaCTX-M genes in diverse Escherichia coli isolates recovered from river water in Japan

Occurrence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBLEC) in environmental waters is of great concern. However, unlike clinical ESBLEC, their genetic characteristics, in particular the genetic contexts of ESBL genes, are not well understood. In this study, we sequenced and analyzed the genomes of CTX-M-producing E. coli isolates recovered from river water to fully characterize the genetic contexts of blaCTX-M genes. Among the 14 isolates with completed genomes, blaCTX-M genes were detected on the chromosome in nine isolates. All but one chromosomal blaCTX-M genes were associated with ISEcp1 and were carried on different transposition units ranging in size from 2, 855 bp to 11, 093 bp; the exception, blaCTX-M-2, was associated with ISCR1. The remaining five isolates carried blaCTX-M genes on epidemic IncI1 plasmids of different sequence types (STs) (ST3, ST16, ST113, and ST167) (n = 4) or on an IncB/O/K/Z plasmid (n = 1). This study revealed that environmental E. coli carry blaCTX-M genes in diverse genetic contexts. Apparent high prevalence of chromosomal blaCTX-M potentially indicates that some E. coli can stably maintain blaCTX-M genes in environmental waters, though further studies are needed to confirm this

Frecuencia y subtipos del gen blaCTX-M en enterobacterias productoras de BLEE aisladas de urocultivos en el Instituto Nacional de Enfermedades Neoplásicas de enero a diciembre del 2017

Determina la frecuencia y subtipos del gen blaCTX-M en enterobacterias productoras de BLEE aisladas de urocultivos en el INEN de enero a diciembre del 2017. Métodos: Se estudiaron un total de 57 aislados de enterobacterias productoras de BLEE de urocultivos de pacientes hospitalizados del INEN durante enero a diciembre del 2017. A todos los aislados se les realizó la detección de los genes blaCTX-M y los subtipos blaCTX-M-1, blaCTX-M-2 y blaCTX-M-9 mediante un PCR convencional. Resultados: De las 57 enterobacterias productoras de BLEE de urocultivos que fueron analizadas el 63,2% correspondieron a E. coli (36/57); 33,3%, a K. pneumoniae (19/57) y 3,5%, a P. mirabilis (2/57). Por otro lado, el 87,7% de las enterobacterias productoras de BLEE presentaron el gen blaCTX-M; entre estas: el 82% perteneció al subtipo blaCTX-M-1; 16%, al subtipo blaCTX-M-9 y el 2%, al subtipo blaCTX-M-2. Respecto al perfil de susceptibilidad a los antibióticos, se observó una alta resistencia a la CRO (98,2%), CIP (91,2%) y CAZ (59,6%); se encontraron 4 aislados resistentes a carbapenémicos. Se observó mayor sensibilidad para amikacina (98,2%). Conclusiones: Se demostró una alta frecuencia (87,7%) del gen blaCTX-M entre las enterobacterias productoras de BLEE, siendo el subtipo predominante el subtipo blaCTX-M-1, seguido del subtipo blaCTX-M-9 y subtipo blaCTX-M-2 con menor frecuencia. Se observó asociación entre la presencia del gen blaCTX-M con el perfil de susceptibilidad a gentamicina, ceftriaxona y ciprofloxacina. Palabras clave: Enterobacterias, urocultivo, paciente oncológico, BLEE, blaCTX-M, subtipos CTX-M.Tesi

The Emergence of Chromosomally Located blaCTX-M-55 in Salmonella From Foodborne Animals in China

The emergence and increase in prevalence of resistance to cephalosporins amongst isolates of Salmonella from food animals imposes a public health threat. The aim of the present study was to investigate the prevalence and characteristics of CTX-M-producing Salmonella isolates from raw meat and food animals. 27 of 152 (17.76%) Salmonella isolates were ESBL-positive including 21/70 (30%) from food animals and 6/82 (7.32%) from raw meat. CTX-M-55 was the most prevalent ESBL type observed (12/27, 44.44%). 7 of 12 CTX-M-55-positive Salmonella isolates were Salmonella Indiana, 2 were Salmonella Typhimurium, 2 were Salmonella Chester, and the remaining isolate was not typeable. Eight CTX-M-55-positive Salmonella isolates were highly resistant to fluoroquinolones (MICCIP = 64 ug/mL) and co-harbored aac(6')-Ib-cr and oqxAB. Most of the CTX-M-55 positive isolates (11/12) carried blaCTX-M-55 genes on the chromosome, with the remaining isolate carrying this gene on a transferable 280 kb IncHI2 plasmid. A chromosomal blaCTX-M-55 gene from one isolate transferred onto a 250 kb IncHI2 plasmid which was subsequently conjugated into recipient strain J53. PFGE and MLST profiles showed a wide range of strain types were carrying blaCTX-M-55. Our study demonstrates the emergence and prevalence of foodborne Salmonella harboring a chromosomally located blaCTX-M-55 in China. The co-existence of PMQR genes with blaCTX-M-55 in Salmonella isolates suggests co-selection and dissemination of resistance to both fluoroquinolones and cephalosporins in Salmonella via the food chain in China represents a public health concern

Antimicrobial activity of quinoxaline 1,4-dioxide and three derivatives

O presente trabalho descreve o estudo da actividad e antimicrobiana de quarto derivados da quinoxalina N,N-dióxido: quinoxalina 1,4-dióxido, 2-metilquinoxalina 1,4- dióxido, 6-cloro-2,3-dimetilquinoxalina 1,4-dióxido e 3-benzoil-2-metilquinoxalina 1,4- dióxido contra as estirpes bacterianas Geobacillus stearothermophilus ATCC 10149, Escherichia coli ATCC 25922, Escherichia coli HB101, Escherichia coli (blaTEM, blaCTX-M) e Salmonella (blaCTX-M), assim como contra a estirpe de levedura Saccharomyces cerevisiae PYCC 4072. A determinação da concentração mínima inibitória (MIC) foi realizada pelo método de diluição. Os valores de MIC’s foram estimados para cada composto e estirpe. Os resultados obtidos sugerem potenciais novas drogas para quimioterapia.The present work reports the study of the antimicrobial activity of four quinoxaline N,N-dioxide: quinoxaline 1,4-dioxide, 2-methylquinoxaline 1,4-dioxide, 6- chloro-2,3-dimethylquinoxaline 1,4-dioxide and 3-benzoyl-2-methylquinoxaline 1,4- dioxide against Geobacillus stearothermophilus ATCC 10149, Escherichia coli ATCC 25922, Escherichia coli HB101, Escherichia coli (blaTEM, blaCTX-M) and Salmonella (blaCTX-M) bacterial strains and also against the yeast Saccharomyces cerevisiae PYCC 4072. The determination of the minimal inhibitory concentration (MIC) was performed by the dilution method. The MIC values were estimated for each compound and each microorganism. The results obtained suggest potential new drugs for antimicrobial chemotherapy

Emergence and Evolution of Multidrug-Resistant Klebsiella pneumoniae with both blaKPC and blaCTX-M Integrated in the Chromosome

The extended-spectrum-β-lactamase (ESBL)- and Klebsiella pneumoniaecarbapenemase (KPC)-producing Enterobacteriaceae represent serious and urgent threats to public health. In a retrospective study of multidrug-resistant K. pneumoniae, we identified three clinical isolates, CN1, CR14, and NY9, carrying both blaCTX-M and blaKPC genes. The complete genomes of these three K. pneumoniae isolates were de novo assembled by using both short- and long-read whole-genome sequencing. In CR14 and NY9, blaCTX-M and blaKPC were carried on two different plasmids. In contrast, CN1 had one copy of blaKPC-2 and three copies of blaCTX-M-15 integrated in the chromosome, for which the blaCTX-M-15 genes were linked to an insertion sequence, ISEcp1, whereas the blaKPC-2 gene was in the context of a Tn4401a transposition unit conjugated with a PsP3-like prophage. Intriguingly, downstream of the Tn4401a-blaKPC-2-prophage genomic island, CN1 also carried a clustered regularly interspaced short palindromic repeat (CRISPR)-cas array with four spacers targeting a variety of K. pneumoniae plasmids harboring antimicrobial resistance genes. Comparative genomic analysis revealed that there were two subtypes of type I-E CRISPR-cas in K. pneumoniae strains and suggested that the evolving CRISPR-cas, with its acquired novel spacer, induced the mobilization of antimicrobial resistance genes from plasmids into the chromosome. The integration and dissemination of multiple copies of blaCTX-Mand blaKPC from plasmids to chromosome depicts the complex pandemic scenario of multidrug-resistant K. pneumoniae. Additionally, the implications from this study also raise concerns for the application of a CRISPR-cas strategy against antimicrobial resistance

Phylogenetic groups and cephalosporin resistance genes of Escherichia coli from diseased food-producing animals in Japan

A total of 318 Escherichia coli isolates obtained from different food-producing animals affected with colibacillosis between 2001 and 2006 were subjected to phylogenetic analysis: 72 bovine isolates, 89 poultry isolates and 157 porcine isolates. Overall, the phylogenetic group A was predominant in isolates from cattle (36/72, 50%) and pigs (101/157, 64.3%) whereas groups A (44/89, 49.4%) and D (40/89, 44.9%) were predominant in isolates from poultry. In addition, group B2 was not found among diseased food-producing animals except for a poultry isolate. Thus, the phylogenetic group distribution of E. coli from diseased animals was different by animal species. Among the 318 isolates, cefazolin resistance (minimum inhibitory concentrations: ≥32 μg/ml) was found in six bovine isolates, 29 poultry isolates and three porcine isolates. Of them, 11 isolates (nine from poultry and two from cattle) produced extended spectrum β-lactamase (ESBL). The two bovine isolates produced blaCTX-M-2, while the nine poultry isolates produced blaCTX-M-25 (4), blaSHV-2 (3), blaCTX-M-15 (1) and blaCTX-M-2 (1). Thus, our results showed that several types of ESBL were identified and three types of β-lactamase (SHV-2, CTX-M-25 and CTX-M-15) were observed for the first time in E. coli from diseased animals in Japan