scholarly journals Detection of Plasmid-Mediated β-Lactamase Genes and Emergence of a Novel AmpC (CMH-1) in Enterobacter cloacae at a Medical Center in Southern Taiwan

2018 ◽  
Vol 8 (1) ◽  
pp. 8 ◽  
Author(s):  
Yee-Huang Ku ◽  
Mei-Feng Lee ◽  
Yin-Ching Chuang ◽  
Wen-Liang Yu

The plasmid-mediated extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases in Enterobacter spp. have increasingly been reported. In this study, we investigated the prevalence of the plasmid-mediated β-lactamases in Enterobacter cloacae from bloodstream isolates at a medical center in southern Taiwan. ESBL and ampC genes were detected by PCRs and DNA sequencing. Conjugation experiments were conducted to confirm the transferability of the genetic resistance trait. Among 41 non-repetitive blood isolates of cefuroxime-resistant E. cloacae, eight isolates exhibited ESBL phenotype confirmed by double-disk synergistic tests. Nearly all the strains were susceptible to carbapenems. The prevalence rate of the plasmid-mediated blaampC genes was 73% (30/41), including one blaDHA-1, one blaMIR-6, two novel blaCMH-1 genes and other blaACT-like genes. Coexistence of plasmid-mediated blaACT and ESBL genes (10 with blaSHV-12 and one with blaCTX-M-3) was observed. Successful transmissions of the blaACT and blaCMH-1 were demonstrated in some transconjugants. The inducible or derepressed CMH-1 had expanded activity of isolates versus ceftazidime. Enterobacterial repetitive intergenic consensus (ERIC)-PCR analysis and pulsotype showed distinct patterns suggesting non-clonal relationship. In conclusion, plasmid-mediated blaACT-like ampC genes in E. cloacae isolates have been highly prevalent in southern Taiwan and may continue genetic evolution, contributing to the complexities in antibiotic-resistant mechanisms.

2009 ◽  
Vol 50 (1) ◽  
pp. 3-7 ◽  
Author(s):  
Hsiao-Neng Chen ◽  
Meng-Luen Lee ◽  
Wai-Kit Yu ◽  
Yue-Wen Lin ◽  
Lon-Yen Tsao

2020 ◽  
Vol 23 (2) ◽  
pp. 228-235
Author(s):  
Adnan Ahmed ◽  
Jassim M Abdo

In last ten years, there has been a developing enthusiasm for microscopic organisms from the genus Anaplasma, particularly the species A. ovis. It is associated with the pathogenic action of these microscopic organisms in livestock. Anaplasma ovis is a tick-borne obligate intracellular rickettsial bacterium that causes anaplasmosis in domestic and wild small ruminants. The samples of the present study were collected from small ruminants from inside seven distinct regions (Akre, Simele, Zummar, Feshchapoor, Deraboon, Bajed Kandal,Karoda)of Duhok province, 389 (goats 75 and sheep 314) during the period of April and May 2018, blood sample were taken and thin smear was formed, after Giemsa’s staining the slide is observed under microscope. In this study used Giemsa stain for microscopic examination out of 389 animals 250 were found positive for Anaplasma ovis infection with a prevalence rate of 64.26 % and 139 of them were negative with a prevalence rate of 35.73 %. According to the species of animals, the highest prevalence of A. ovis infection in animals by using microscopic examination was 67.83 %, 213 positive sample from total 314 blood samples from sheep and lowest prevalence was 49.33 %, 37 positive sample from total 75 blood samples from goats. PCR analysis of 100 blood samples obtained from total 250 positive blood samples after DNA extraction and measure of concentration and purity we used 2 primers that target major surface protein 4 (MSP4) in A. ovis genomic DNA. The results of PCR test with major surface protein 4 primer was 83 samples positive from total 100 samples, According to the species of animals, the highest prevalence of A. ovis was 83.7 %, 72 positive sample from total 86 blood samples from sheep and lowest prevalence was 78.5 %, 11 positive sample from total 14 blood samples from goats.


2019 ◽  
Vol 122 (4) ◽  
pp. 465-472 ◽  
Author(s):  
Charles C. Bell ◽  
Omer Gilan

AbstractAs well as undergoing genetic evolution, cancer cells can alter their epigenetic state to adapt and resist treatment. This non-genetic evolution is emerging as a major component of cancer resistance. Only now are we beginning to acquire the necessary data and tools to establish some of the underlying principles and mechanisms that define when, why and how non-genetic resistance occurs. Preliminary studies suggest that it can exist in a number of forms, including drug persistence, unstable non-genetic resistance and, most intriguingly, stable non-genetic resistance. Exactly how they each arise remains unclear; however, epigenetic heterogeneity and plasticity appear to be important variables. In this review, we provide an overview of these different forms of non-genetic resistance, before exploring how epigenetic heterogeneity and plasticity influence their emergence. We highlight the distinction between non-genetic Darwinian selection and Lamarckian induction and discuss how each is capable of generating resistance. Finally, we discuss the potential interaction between genetic and non-genetic adaptation and propose the idea of ‘the path of most resistance’, which outlines the variables that dictate whether cancers adapt through genetic and/or epigenetic means. Through these discussions, we hope to provide a conceptual framework that focuses future studies, whose insights might help prevent or overcome non-genetic resistance.


2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Garima Bansal ◽  
Rachelle Allen-McFarlane ◽  
Broderick Eribo

The occurrence of carbapenem-resistant (CR) strains of Acinetobacter baumannii is reported to contribute to the severity of several nosocomial infections, especially in critically ill patients in intensive care units. The present study aims to determine the antibiotic susceptibility, clonality, and genetic mechanism of carbapenem resistance in twenty-eight Acinetobacter baumannii isolates from four hospitals in Washington DC. The antibiotic susceptibility of the isolates was determined by VITEK 2 analyses, while PCR was used to examine the presence of antibiotic-resistant genes and mobile genetic elements. Trilocus multiplex-PCR was used along with pulsed-field gel electrophoresis (PFGE) for strain typing and for accessing clonal relationships among the isolates. Antimicrobial susceptibility testing indicated that 46% of the isolates were carbapenem-resistant and possessed MDR and XDR phenotypes. PFGE clustered the 28 isolates into seven clonal (C1–C7) complexes based on >75% similarity cut-off. Thirty-six percent of the isolates belonged to international clone II, while 29% were assigned to Group 4 by trilocus multiplex-PCR. Although the blaOXA-51-like gene was found in all the isolates, only 36% were positive for the blaOXA-23-like gene. PCR analysis also found a metallo-β-lactamase (MBL) gene (blaVIM) in 71% of the isolates. Of the 13 CR isolates, 8 were PCR positive for both blaVIM and blaOXA-23-like genes, while 5 harbored only blaVIM gene. This study revealed the emergence of VIM carbapenemase-producing A. baumannii isolates, which has not been previously reported in the United States.


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