Second nationwide surveillance of bacterial pathogens in patients with acute uncomplicated cystitis conducted by Japanese Surveillance Committee from 2015 to 2016: antimicrobial susceptibility of Escherichia coli, Klebsiella pneumoniae, and Staphylococcus saprophyticus

The Japanese Surveillance Committee conducted a second nationwide surveillance of antimicrobial susceptibility patterns of uropathogens responsible for acute uncomplicated cystitis (AUC) in premenopausal patients aged 16–40 years old at 31 hospitals throughout Japan from March 2015 to February 2016. In this study, the susceptibility of causative bacteria (Escherichia coli, Klebsiella pneumoniae, Staphylococcus saprophyticus) for various antimicrobial agents was investigated by isolation and culturing of organisms obtained from urine samples. In total, 324 strains were isolated from 361 patients, including E. coli (n = 220, 67.9%), S. saprophyticus (n = 36, 11.1%), and K. pneumoniae (n = 7, 2.2%). The minimum inhibitory concentrations (MICs) of 20 antibacterial agents for these strains were determined according to the Clinical and Laboratory Standards Institute (CLSI) manual. At least 93% of the E. coli isolates showed susceptibility to fluoroquinolones and cephalosporins, whereas 100% of the S. saprophyticus isolates showed susceptibility to fluoroquinolones and aminoglycosides. The proportions of fluoroquinolone-resistant and extended-spectrum β-lactamase (ESBL)-producing E. coli strains were 6.4% (13/220) and 4.1% (9/220), respectively. The antimicrobial susceptibility of K. pneumoniae was retained during the surveillance period, while no multidrug-resistant strains were identified. In summary, antimicrobial susceptibility results of our second nationwide surveillance did not differ significantly from those of the first surveillance. Especially the numbers of fluoroquinolone-resistant and ESBL-producing E. coli strains were not increased in premenopausal patients with AUC in Japan

Comparison of speech perception lists used to evaluate Japanese single syllable hearing

Citation: Matsuda Y, Okuda T, Kamie A, Miyanaga N, Nakamura T, Shirane M, Shimoara S, Ganaha A, Tono T. Comparison of speech perception lists used to evaluate Japanese single syllable hearing. Auris Nasus Larynx. 2022 Jun;49(3):383-388. doi: 10.1016/j.anl.2021.09.007. Epub 2021 Oct 19. PMID: 34674888

Analysis of the Neuraminidase Amino Acid Sequences of Influenza A/H1N1pdm09, A/H3N2, and B Viruses Isolated from Influenza Patients in the 2013/14 Japanese Influenza Season

Background : Neuraminidase (NA) is an essential surface protein for influenza virus replication. NA inhibitors are commonly used for the treatment of influenza patients in Japan. Several mutations that reduce the effect of NA inhibitors have been reported. We sequenced the whole NA segment of isolated virus from influenza patients and investigated the relation between the NA amino acid sequence and the 50% inhibitory concentration (IC_<50>) of four NA inhibitors. Materials and Methods : A total of 20 viruses that showed high or low IC_<50> of NA inhibitors were selected from A/H1N1pdm09, A/H3N2, and B isolates from the viruses isolated from patients in the 2013-14 influenza season. Viral RNA was extracted and RT-PCR was done. The amplified genome was sequenced using a “next generation sequencer”, and the deduced amino acid sequences were analyzed. Results : Two A/H1N1pdm09 viruses that showed very high IC_<50> for oseltamivir (150nM and130nM) contained the H275Y mutation. Otherwise, no significant relation was found between the NA amino acids and the IC_<50> of the four NA inhibitors. There was no significant relation between the NA amino acids and the IC_<50> of the four NA inhibitors for A/H3N2 viruses. The B viruses that showed a high IC_<50> for oseltamivir and laninamivir shared some amino acids. The B viruses that showed a high IC_<50> of zanamivir and peramivir also shared some amino acids. They were different from the shared amino acids found for oseltamivir and laninamivir. Conclusion : The previously reportedH275 Y mutation that causes oseltamivir resistance was found in the two A/H1N1pdm09 viruses that showed a very high IC_<50> for oseltamivir. No additional NA amino acid sequences related to the IC_<50> of the four NA inhibitors was found. The meaning of the shared amino acids among B viruses that showed a high IC_<50> would be an interesting target for further investigation

2011/12及び2012/13年インフルエンザ流行期に患者より分離されたA/H3N2型ウイルス96株のNA遺伝子配列と薬剤感受性との関連についての検討

Background : Influenza virus has neuraminidase (NA), a surface protein with enzymatic activity that is essential for virus replication. Mutation may affect the effectiveness of NA inhibitors that are used for the treatment of influenza patients. In this study, we determined the NA gene sequences from the clinical isolates of influenza patients to examine the chronological genetic changes and the relation to drug susceptibility. Methods : For 96 A/H3N2 virus isolates the 50% inhibitory concentration (IC_<50>) (48 each from the 2011-12 and 12-13 influenza seasons) was measured. RT-PCR was done with extracted viral RNA, followed by nucleotide sequencing. Results : One putative amino acid mutation, D151N, was found in an NA activity-related cite in five of ninety-six tested isolate. The mutation did not affect the IC_<50> value. The mutations identified at amino acid positions 387 and 400 were statistically correlated with an increased IC_<50> value, although the change was less than ten times, suggesting no significant difference in the clinical effectiveness. A small number of isolates showed mutation in the T and/or B cell epitope region of NA. Conclusion : No mutation that affected the IC_<50> value or effectiveness of NAIs was detected. Antigenic mutations of NA, which influence the selection of epidemic strains, were not determined. Continuous observation will be necessary to further clarify the genetic features of NA