Antimicrobial Activity of Peracetic Acid Preparation in the Presence of Various Compounds

It is known that peracetic acid (PAA) is one of the few powerful antimicrobial agents available for use as a sporicidal agent. In this study, the antimicrobial action of a commercial preparation of PAA is characterized and the effects of chemicals on the action are investigated using Escherichia coli cells. The antimicrobial activity of the PAA preparation used in this study was markedly higher under high temperatures and low pHs. However, such a high activity of PAA preparation was strictly inhibited in the presence of a chemical, such as some amino acids, metal salts, and metal chelating agents. By the quantitative analysis of PAA and H_2O_2, it was also observed that these inhibitory chemicals had a strong influence on decomposition of PAA. Although manganese sulfate, and O, O\u27-bis(2-aminoethyl) ethyleneglycol-N, N, N\u27, N\u27-tetraacetic acid (EGTA) had a slight inhibitory effect on the PAA antimicrobial action, these chemicals decomposed PAA, suggesting that these chemicals might reduce cell activity to the PAA resistance. Furthermore, our results indicate that the H_2O_2 contained in the PAA preparation has a slight effect on the antimicrobial action of the PAA preparation

Cyanide Production by Chromobacterium piscinae Shields It from Bdellovibrio bacteriovorus HD100 Predation

Predation of Chromobacterium piscinae by Bdellovibrio bacteriovorus HD100 was inhibited in dilute nutrient broth (DNB) but not in HEPES. Experiments showed that the effector responsible was present in the medium, as cell-free supernatants retained the ability to inhibit predation, and that the effector was not toxic to B. bacteriovorus. Violacein, a bisindole secondary metabolite produced by C. piscinae, was not responsible. Further characterization of C. piscinae found that this species produces sufficient concentrations of cyanide (202 mu M) when grown in DNB to inhibit the predatory activity of B. bacteriovorus, but that in HEPES, the cyanide concentrations were negligible (19 mu M). The antagonistic role of cyanide was further confirmed, as the addition of hydroxocobalamin, which chelates cyanide, allowed predation to proceed. The activity of cyanide against B. bacteriovorus was found to be twofold, depending on the life cycle stage of this predator. For the attack-phase predatory cells, cyanide caused the cells to lose motility and tumble, while for intra-periplasmic predators, development and lysis of the prey cell were halted. These findings suggest that cyanogenesis in nature may be employed by the bacterial strains that produce this compound to prevent and reduce their predation by B. bacteriovorus. IMPORTANCE Bacterial predators actively attack, kill, and enter the periplasm of susceptible Gram-negative bacteria, where they consume the prey cell components. To date, the activity of B. bacteriovorus HD100 has been demonstrated against more than 100 human pathogens. As such, this strain and others are being considered as potential alternatives or supplements to conventional antibiotics. However, the production of secondary metabolites by prey bacteria is known to mitigate, and even abolish, predation by bacterivorous nematodes and protists. With the exception of indole, which was shown to inhibit predation, the effects of bacterial secondary metabolites on B. bacteriovorus and its activities have not been considered. Consequently, we undertook this study to better understand the mechanisms that bacterial strains employ to inhibit predation by B. bacteriovorus HD100. We report here that cyanogenic bacterial strains can inhibit predation and show that cyanide affects both attack-phase predators and those within prey, i.e., in the bdelloplast

Analysis of a city‐wide COVID‐19 prevention strategy for aged‐care facilities during third and fifth waves of COVID‐19 in Kyoto City, Kyoto, Japan

[Background] During the third wave of the COVID-19 pandemic at the end of 2020, clusters occurred frequently in aged-care facilities (ACFs), which put pressure on the medical field in Japan. Based on this experience, Kyoto University and Kyoto City collaborated to promote a citywide COVID-19 prevention strategy to prevent the spread of COVID-19 within ACFs. The aim of this study was to clarify the effect of the prevention strategy among ACFs in Kyoto City during the third and fifth waves of the pandemic. [Methods] During the study period, the following measures were adopted as the prevention strategy in all ACFs: (1) active polymerase chain reaction (PCR) mass testing and facility-wide testing when a single case was identified, (2) implementation of strategies to prevent transmission within a facility, and (3) vaccination program for ACFs. [Results] Of the 1, 144 facilities subjected to the mass testing, 71.0% participated in the whole program including active PCR testing. The remainder participated in the rest of the programs. The prevalence of ACF-related COVID-19 cases among total COVID-19 cases in Kyoto City decreased from 7.9% in the third wave to 4.1% in the fourth wave and 2.1% in the fifth wave. The incidence of clusters and proportion of severe elderly cases also decreased during the study period. [Conclusions] A city-wide multidisciplinary effort including PCR mass testing and a vaccination program in cooperation with a university and local administrative office successfully reduced the clusters and transmission in ACFs in Kyoto City, Japan

Clonal Expansion of Multidrug-Resistant <i>Streptococcus dysgalactiae</i> Subspecies <i>equisimilis</i> Causing Bacteremia, Japan, 2005–2021

Incidence of Streptococcus dysgalactiae subspecies equisimilis (SDSE) bacteremia is increasing in the Kyoto-Shiga region of Japan. We retrospectively analyzed clinical features of SDSE bacteremia and conducted comparative genomic analyses of isolates collected from 146 bacteremia episodes among 133 patients during 2005-2021. Of those patients, 7.7% required vasopressor support, and 7.0% died while in the hospital. The prevalence of isolates resistant to erythromycin, minocycline, and clindamycin increased from 8.6% during 2005-2017 to 21.6% during 2018-2021. Our genomic analysis demonstrated that sequence type 525 and clonal complex 25 were predominant in SDSE isolates collected during 2018-2021. In addition, those isolates had acquired 2 antimicrobial-resistance genes, ermB and tetM, via Tn916-like integrative and conjugative elements (ICEs). Phylogenetic analysis revealed clonal distribution of Tn916-like ICEs in SDSE isolates. Our findings suggest that Tn916-like ICEs contributed to the emergence and recent increase of multidrug-resistant SDSE bacteremia in this region of Japan

Efficacy of increased-dose erlotinib for central nervous system metastases in non-small cell lung cancer patients with epidermal growth factor receptor mutation

Recent reports indicate that refractory central nervous system (CNS) metastases of non-small cell lung cancer (NSCLC) are improved by high-dose gefitinib or erlotinib administration. We describe a Japanese woman with NSCLC and CNS metastases who was resistant to 75 mg daily erlotinib, but the metastases were improved by 150 mg daily erlotinib. We investigated the plasma and CSF concentrations of erlotinib at each dose as well as the correlation between the plasma and CSF concentrations of erlotinib

Studies on the Monumental Stone Blocks of Behbeit el-Hagar Temple, Middle Delta, Egypt

In the present study, an overall examination of the monumental stone blocks preserved in the site of Behbeit el-Hagar Temple is performed. The site is entirely ruined. Some of the monumental stone blocks have been sampled　and characterized petrographically and mineralogically in the laboratory. They are formed either of mainly coarse　grained granite or fine grained granite, granodiorite , basalt and andesite. These monumental blocks demonstrate　degradation morphologies. The observed stone damage takes various phenomena, such as missing parts, scratch,　detachment, discoloration, cracks and pitting as well as biological degradations. The petrographic and the mineralogical characteristics of the studied granitoids monumental blocks match well with the pink granite and granodiorite coming from the Aswan area. The initial deterioration of the studied stones exposed to the outdoor environment and the action of agents such as rain, wind, temperature, sunlight and pollution may be due to physical and chemical processes. These agents cause an increase in the surface area of the stone by the formation of micro- and macrofissures or the formation of encrustations. Most of the surface of the monuments has undergone biological alteration by living micro organisms (fungi, bacteria and lichens) that have been colonized on many surface areas. The present microorganisms. both fungi and bacteria, have been characterized and identified . Fungi were characterized by morphological methods and nutritional physiology whereas bacterial strains were analyzed by PCR primers and rDNAs. Twelve fungal taxa and ten bacterial taxa were identified in all the collected and analyzed samples.departmental bulletin pape

文化財とカビによるバイオフィルム

Studies on the biomatrix problem are mainly discussed regarding bacteria. Although fungi are one kind of microbe and contaminate several substrates in wet environments, they differ from other microbes in their growth pattern, ecological characteristics, biological figures and morphological findings. Therefore, fungi have never been studied and discussed on biofilm problems. According to our survey on cultural assets of stone, wood, plastics, rubber and textiles in wet environments, these materials are attacked and damaged and deteriorated by fungi. In this review, the fungal biofilm on cultural assets in cultural facilities is explained.バイオフィルム問題や研究の多くは細菌で議論されてきている。同じ微生物であるカビを含めた真菌は、細菌に比べると発育様式、形状、性状で大きく異なる。そのため今までほとんどバイオフィルムとして議論や研究の対象とされてこなかった。しかし、湿性環境にみる文化財のカビによる被害をマクロ・ミクロで詳細に観察すると、その発生現象、発生環境、原因カビなどから少なくとも細菌で定義されているバイオフィルムと必ずしも同一ではないが、広義に解釈するとカビによるバイオフィルムも存在することが確認できた。そこで本稿では文化財のカビ問題に焦点を合わせ、高湿環境で起こりやすいカビ被害とバイオフィルムをまとめた。departmental bulletin pape