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Herskind Harrell posted an update 6 months, 3 weeks ago
4±11.8, 42.8±21.8 and 66.6±39.1. Emergence of resistance as indicated by >2 log growth on MICx8 recovery media was maximal at AUC/MIC ratios of 10-40 and was suppressed at AUC/MIC ratios of ≥250. CONCLUSIONS The dominant PDI for fosfomycin against S.aureus are Cmax/MIC in terms of reduction of bacterial load and AUC/MIC in terms of suppressing emergence of resistance. AUC/MIC ratios of 20-75 are associated with a -1 log reduction in bacterial load and AUC/MIC of 10-40 maximally increase emergence of resistance. V.Clostridium difficile infection (CDI) is the leading cause of antibiotic-associated diarrhea worldwide. In order to gain a better understanding about the molecular epidemiology of C. difficile in Beijing, China, we performed molecular typing, antimicrobial susceptibility test, and drug resistance gene sequencing on 174 C. difficile strains collected from four large tertiary hospitals in Beijing. A total of 31 sequence types (STs) were identified among the 174 strains, of which ST81 was found to be the most prevalent clone, accounting for 26.4% (46/174) of the isolates, followed by ST2 (16.7%, 29/174) and ST54 (9.8%, 17/174). All the isolates were susceptible to metronidazole and vancomycin. The test strains displayed resistance rates of 97.1%, 44.3%, and 44.3% for ciprofloxacin, levofloxacin, and moxifloxacin, respectively. The ST81 isolates displayed a drug resistance rate of 97.8% for the antibiotics levofloxacin and moxifloxacin, which was significantly higher than the rates of the ST2 (0%), ST54 (17.6%), and ST42 (0%) isolates (P less then 0.05). An amino acid mutation, T82I, was identified in GyrA and the total mutation rate of the C. difficile strains was 40.8% (71/174), while the mutation rate of the ST81 strains was 95.7% (44/46). Three amino acid mutations including D426N, S366A, and D426V were identified in GyrB and the total mutation rate of GyrB was 39.1%. The double-site mutation in GyrB, S366A+D426V was identified in all the ST81 (n=46) strains. In conclusion, the C. difficile ST81 clone showed high levels of fluoroquinolone resistance in Beijing, China, thus highlighting the need for nationwide surveillance of CDI. V.The emergence of linezolid-resistant Enterococcus spp. (LRE) due to transferable resistance determinants is a matter of concern. To understand the contribution of the plasmid-encoded optrA and poxtA genes to the emergence of LRE, we analysed clinical isolates from different Spanish hospitals submitted to the Spanish Reference Laboratory from 2015-2018. Resistance mechanisms to linezolid were screened in all isolates by PCR and sequencing. Genetic relatedness of all Enterococcus spp. carrying optrA and poxtA was studied by PFGE and MLST, and antibiotic susceptibility was tested by broth microdilution using EUCAST standards. A total of 97 LRE isolates were studied; in 94 (96.9%) of them, at least one resistance determinant was detected; 84 (86.6%) isolates presented a single resistance mechanism as follows 45 (53.6%) carried the optrA gene, 38 (45.2%) the G2575T mutation, and one (1.2%) the poxtA gene; in addition, five (5.1%) carried both the optrA gene and the G2575T mutation, and five (5.1%) both optrA and poxtA genes. The optrA gene was more frequent in E. faecalis (83.6%) than in E. faecium (11.1%) and was mainly associated with community-acquired urinary tract infections. Carriage of the poxtA gene was more frequent in E. faecium (13.9%) than in E. see more faecalis (1.6%). Among optrA-positive E. faecalis isolates, two main clusters were detected by PFGE. These two clusters belonged to ST585 and ST480 and were distributed throughout 11 and 6 Spanish provinces, respectively. This is the first description of LRE carrying the poxtA gene in Spain, including co-existence of optrA and poxtA in five isolates. V.The importance of plasmid-mediated quinolone resistance (PMQR) in Enterobacteriales and its high incidence has been emphasized many times. However, a clinical strain carrying more than three PQMR genes is rare. In this study, we sequenced plasmid transconjugants from a donor strain carrying four different PMQR genes to establish their genetic locations. An Escherichia coli clinical strain displayed remarkable quinolone resistance with a ciprofloxacin MIC of 1024 mg/L, carrying 4 PMQR genes (qnrA1, qepA1, aac(6′)1b-cr and oqxAB). When outcrossed to E. coli J53 AziR, different PMQR genes were transferred, and the resulting strains 7C and 8C were chosen for further characterization. Plasmids were extracted and sequenced by the Illumina and Oxford Nanopore Technologies platforms. S1 nuclease-PFGE was used to estimate the number and size of plasmids. The parental strain had three plasmids bands as determined by PFGE. Transconjugant 8C obtained 3 plasmids pMG336 (162,647 bp, F18A-B1C4) carrying oqxAB; pMG335 carrying qepA1 (73,874 bp, F2A-B-); and pMG334 (59,724 bp, IncN (ST5)) with qnrA1 and aac(6′)1b-cr. Interestingly, strain 7C obtained plasmid pMG333 (134,435 bp) that was not present in the parental strain but was an IncN-IncF cointegrate of plasmids pMG334 and pMG335 linked via insertion sequence IS26. We described the complete nucleotide sequence of three plasmids carrying four PMQR genes in a single strain and the plasmid profile obtained after outcrosses. In addition, we describe a cointegrate of two plasmids formed with flanking insertion sequences. V.BACKGROUND In recurrent uncomplicated lower urinary tract infections (uLUTI) bacteriuria below 103 CFU/ml is usually not investigated. OBJECTIVE Molecular-genetic characteristics of the pathogenic potential of Enterobacteriaceae isolated during the inter-episode period of recurrent uLUTI at bacteriuria of 102 CFU/ml. MATERIALS AND METHODS Midstream urine samples taken from 169 women with recurrent uLUTI between episodes were examined on six media. 15 Enterobacteriaceae strains at low level bacteriuria (102 CFU/ml) were analyzed (PCR) for the presence of virulence factor (VFG) genes papA; papE/F; papGII; afa; bmaE; iutA; feoB; fyuA; kpsMTII; usp. RESULTS All 169 patients had leukocyturia and asymptomatic bacteriuria, 62 of them due to enterobacteria 102 CFU/ml – 15(24.2%), 103 CFU/ml – 10(16.1%), > 103 CFU/ml – 37(59.7%). In all 15 strains at low level bacteriuria (102 CFU/ml) VFG were verified 1 VFG (papGII) was found in 2 strains of Klebsiella (13.3%), 3 VFG in 1 strain of Enterobacter (16.7%), from 4 to 9 VFG together – the remaining 12 strains.