Preliminary Remarks Regarding the Prevalence of ESBL-Producing Strains of E. coli and K. Pneumoniae, Isolated from Cows with Clinical Endometritis

ESBL-producing organisms pose unique challenges to clinical microbiologists, clinicians, infection control professionals and antibacterial-discovery scientists. Although the prevalence of ESBLs is not known, it is clearly increasing, and in many parts of the world, 10-40% of strains of E. coli and K. pneumoniae express ESBLs (Rupp and Fey, 2003).The aim of this study was to assess the prevalence of ESBL-positive strains of E. coli and K. pneumoniae in cows with clinical signs of endometritis that were treated exclusively with Oxytetracicline for both diseases of the genital area as well as other bacterial infectious diseases.The study population included 35 Romanian Black Pied cows with clinical signs of endometritis within a farm in North Eastern of Romania. The samples were harvested using sterile cotton swabs that have been further microbiologically processed. For the phenotypic confirmation of the isolated ESBL strains, were used the combined disk test (CLSI, 2014) and the Oxoid Brilliance chromogenic ESBL Agar medium. The taxonomic classification of the isolated colonies was carried out by testing some minimal biochemical characteristics by using the MIU and TSI tests.A total of 47 bacterial strains were isolated from uterine secretions, derived from the 35 cows included in this trial. From the total of 47 isolated bacterial strains, 17 belonged to E. coli and K. pneumoniae species, from which, 6 of them were confirmed as being ESBL-positive.In this preliminary study, by phenotypic methods was confirmed a prevalence of 35.3% for the ESBL strains of E. coli and K. pneumoniae, which requires further research to confirm by molecular biology the identification of ESBL resistance genes, but also for the plasmids encoding these gene transmission

Humanized mouse models and human viruses

Well-developed mouse models are important for understanding the pathogenesis and progression of immunological response to viral infections in humans. Moreover, to test vaccines, anti-viral drugs and therapeutic agents, mouse models are fundamental for preclinical investigations. Human viruses, however, seldom infect mice due to differences in the cellular receptors used by the viruses for entry, as well as in the innate immune responses in mice and humans. In other words, a species barrier exists when using mouse models for investigating human viral infections. Developing transgenic (Tg) mice models expressing the human genes coding for viral entry receptors and knock-out (KO) mice models devoid of components involved in the innate immune response have, to some extent, overcome this barrier. Humanized mouse models are a third approach, developed by engrafting functional human cells and tissues into immunodeficient mice. With an increase in the advancement of modern techniques used for genetic manipulation, humanized mice have become an important asset. They are becoming indispensable for analyzing human viral diseases since they nearly recapitulate the human disease. These mouse models also serve to test the efficacy of vaccines and antiviral agents. The development of humanized mouse models offers a preclinical in vivo platform for further characterization of human viral infections and human immune responses triggered by these virus particles. This review highlights recent progress in utilizing humanized mice to decipher human specific immune responses against viral tropism

Mouse models and Sars-Cov-2

Since December 2019, a novel coronavirus SARS-CoV-2 has emerged and rapidly spread throughout the world, resulting in a global public health emergency. COVID-19 is causing a major once-in-a century global pandemic. The emergences of coronaviruses have caused a serious global public health problem because their infection in humans caused the severe acute respiratory disease and deaths. Much more serious than SARS-CoV in 2002, the current SARS-CoV-2 infection has been spreading to more than 213 countries, areas or territories and causing more than 31 million cases and 962,518 deaths (update september 2020). Intensive research efforts have focused on increasing our understanding of viral biology of SARS-CoV-2, improving antiviral therapy and vaccination strategies. The lack of vaccine and antivirals has brought an urgent need for an animal model. The animal models are important for both the fundamental research and drug discovery of coronavirus

Clonal Dissemination of Extended-Spectrum Cephalosporin-Resistant Enterobacterales between Dogs and Humans in Households and Animal Shelters of Romania

Faecal carriage of extended-spectrum cephalosporin-resistant (ESC-R) Enterobacterales in healthy pets is a concerning issue. This study aimed to determine the prevalence, genetic background, and potential for interspecies transmission of these bacteria between dogs and humans within the same household (HH) or shelter environment in Romania. Faecal samples (n = 263) collected from healthy dogs (n = 102), their owners (n = 32), as well as dogs (n = 110) and staff (n = 19) from dog shelters, were screened for ESC-R carriage. Clonal relatedness of canine and human Escherichia coli isolates was established using Fourier Transform Infrared Spectroscopy (FTIR), followed by Illumina WGS of selected isolates. The highest prevalence of ESC-R Enterobacterales faecal carriage was identified in staff working at dog shelters (78.9%), followed by dogs from households (44.11%), dog owners (43.7%), and dogs from shelters (27%). FTIR identified 15 clusters of closely related E. coli isolates, including dog and human isolates from the same environment. Co-carriage of ESC-R isolates in both the dog and owner was identified in 12 HHs (37.5%), with two HHs (6%) having both the owner and dog carrying isolates with identical FTIR spectra, phylogroup, resistance genes, and Inc plasmids. Major ExPEC lineages such as ST127, ST10, ST155, and ST88 were detected in human and dog isolates. Our study revealed a high prevalence of faecal ESC-R E. coli carriage in both dogs and humans from Romanian households and shelters, where bidirectional clonal transmission between humans and dogs is likely. Furthermore, we identified ESC-R Enterobacterales co-carriage in people and dogs sharing the same environment using FTIR, demonstrating its value in AMR surveillance for humans and animals

The Prevalence of Esbl-Producing Strains of E.coli, Isolated from Calves with Colibacilosis - Preliminary Remarks

The animals producing food have become an increasing reservoir of extended spectrum beta-lactamase producing Enterobacteriaceae. The calves and cows are exposed to a greater quantity of antibiotics, but the data concerning the prevalence of ESBL-producing Enterobacteriaceae are not enough, in comparison with other species of animals used for human consumption, such as birds (Hordijk et al., 2013).The aim of this study was to determine the prevalence of ESBL-producing E. coli involved in some episodes of colibacilosis in calves. Faeces samples were collected from 33 calves with the age ranging between 1-2 weeks and that presented clinical signs of colibacilosis. The samples were collected in a sterile medium for the taxonomic isolation and identification of the etiological agent involved, the ESBL screening being conducted subsequently using the ESBL Agar Oxoid Brilliance chromogenic medium. The phenotypic confirmation of the ESBL-producing strains was conducted in accordance with the CLSI (2014) standard through the combined disc method. Following the tests conducted, out of the 33 strains of isolated E. coli, 9 (27, 27%) were phenotypically confirmed as being ESBL strains.The studies that were previously conducted on the dairy farms have pointed out that the young calves rapidly acquire bacterial strains resistant to antibiotics that are often ESBL strains (Hordijk et al., 2013). The prevalence obtained by us, as well as an insufficient quantity of information concerning the antimicrobial resistance on this segment of species of animals used for the human consumption, support conducting a more thorough study, as well as the identification of ESBL resistance genes, but also of the plasmids that encode the transmission of these genes

Characterisation of Extended β-Lactamases and Plasmid Mediated Quinolones Resistancein Escherichia Coli from Shelter Dogs

The aim of this study was to determine the prevalence of β-lactamase (TEM, SHV, OXA), extended-spectrum β-lactamase (ESBL) and genes encoding plasmid mediated resistance to quinolones (PMQR) in extended spectrum cephalosporin (ESC)-resistant Escherichia coli isolated from dog faeces from two shelters in the North-East of Romania. Eighty-eight faecal samples from healthy dogs were analysed by cultivation on Brilliance ESBL medium (Oxoid, UK), followed by phenotipic ESBL screening using combination disc test (CDT). Identification of the E. coli strains was performed by uidA/uspA gene PCR. Susceptibility testing was performed on Mueller-Hinton Agar, with β-lactam and non-β-lactam agents. Identification of β-lactamase genes (blaCTX-M, blaTEM, blaSHV, blaOXA) and PMQR genes (qnrA, qnrB and qnrS) was performed by PCR as previously described. Twenty eight ESC-resistant E. coli (31.81%) were obtained and (n=21/28, 75%) of these were confirmed as ESBLs and showed resistance to cefpodoxime (n=21/28, 75%), amoxicillin/clavulanic acid (n=19/21; 90.48%), and enrofloxacin (n=8/21; 38.09%). Predominant ESBL types were CTX-M-1 (n=15/17, 88.24%) and CTX-M-9 (n=2/17, 11.76%) enzymes. TEM and SHV enzymes were identified in 17.86% and 14.29% of the ESC-resistant isolates, whilst some isolates (n=4) carried only blaTEM and blaSHV. The prevalence of PMQR genes was 28.57% of the 28 ESC resistant isolates, consisting of qnrS (62.5%) and qnrB (37.5%). These findings indicate a high prevalence of ESBLs and PMQR associated resistance E. coli in the normal faecal microbiota of dogs from shelters, which carries the risk for dissemination of these resistance genes to other animals, human or the environment

Preliminary results regarding the prevalence of CTX-M genes identified in E. coli strains isolated from slaughtered pigs

Extended spectrum beta-lactamase (ESBL)-producing enterobacteriaceae and AmpC cephalosporinases are of major importance for public health because these bacteria have low sensitivity to antibiotics such as extended spectrum cephalosporins, which are antimicrobials widely used both in human and in veterinary medicine. Such strains, especially Escherichia coli (E. coli), have been frequently isolated from pigs too, production animals being considered carriers with major implications in the transmission chain of these strains in humans. The aim of this study was to characterise the molecular substrate of ESBL-positive E. coli strains isolated from slaughtered pigs from 3 slaughter houses from the Moldova area by identifying the CTX-M genes. After collection, the samples were primarily processed for phenotypical identification and confirmation of ESBL-positive E. coli strains. Bacterial DNA extraction for the target strains was carried out using the “boiled preps” method. Identification of the blaCTX-M (blaCTX-M-9; blaCTX-M-1) genes was carried out by PCR using the specific protocol. Molecular investigations revealed that out of the 118 analysed samples, the blaCTXM- U gene was identified in 61% (72/118). Characterisation of the CTX-M groups signalled the presence of the CTX-M-1 group in 44/72 (61.11%) of the analysed strains, and the presence of the CTX-M-9 group in 18/72 (25%) of the strains. This study emphasised a high prevalence of CTX-M enzyme-producing E. coli strains isolated from the caecum of slaughtered pigs

Preliminary investigations on prevalence of ESBL-production Escherichia coli strains in swine from Botoșani County

Administration of antimicrobials to food-producing animals increases the risk of higher antimicrobial resistance in normal intestinal flora. The present preliminary study was conducted to investigate the presence of extended spectrum beta-lactamase (ESBL)-producing Escherichia coli strains in healthy swine from Botoșani County. During 2016-2018, a total of 87 samples of luminal contents of gut sections (cecal) were collected and tested. Fifty-one (51,72%) E. coli isolates were identified as ESBL-producing strains. These preliminary results reflect the selective pressure, caused by intense and less prudent use of the antimicrobials in swine production in our country. Moreover, commensal E. coli can be a reservoir for antimicrobial resistance genes, which can be transferred to pathogenic bacteria. Therefore, resistance genes transferring from farm to fork represent a public health emerging danger by the potential of producing difficultto- treat pathogens