An outbreak of amikacin- and ciprofloxacin-resistant Acinetobacter baumannii ST219 in Tokai University hospital's emergency intensive care unit was caused by its colonization in water systems and subsequent spread through oral care using tap water. The outbreak was successfully controlled after replacement of the water system and implementation as of daily cleaning of water taps and oral care with a dry method. It is important to strictly manage the water system in critical care areas.

A series of clinical isolates of drug-resistant (DR) Acinetobacter baumannii with diverse drug susceptibility was detected from eight patients in the emergency intensive care unit of Tokai University Hospital. The initial isolate was obtained in March 2010 (A. baumannii Tokai strain 1); subsequently, seven isolates were obtained from patients (A. baumannii Tokai strains 2–8) and one isolate was obtained from an air-fluidized bed used by five of the patients during the 3 months from August to November 2011. The isolates were classified into three types of antimicrobial drug resistance patterns (RRR, SRR and SSR) according to their susceptibility (S) or resistance (R) to imipenem, amikacin and ciprofloxacin, respectively. Genotyping of these isolates by multilocus sequence typing revealed one sequence type, ST208, whilst that by a DiversiLab analysis revealed two subtypes. All the isolates were positive for blaOXA-51-like and blaOXA-66, as assessed by PCR and DNA sequencing. A. baumannii Tokai strains 1–8 and 10 (RRR, SRR and SSR) had quinolone resistance-associated mutations in gyrA/parC, as revealed by DNA sequencing. The ISAba1 upstream of blaOXA-51-like and aminoglycoside resistance-associated gene, armA, were detected in A. baumannii Tokai strains 1–7 and 10 (RRR and SRR) as assessed by PCR. Among the genes encoding resistance–nodulation–division family pumps (adeB, adeG and adeJ) and outer-membrane porins (oprD and carO), overexpression of adeB and adeJ and suppression of oprD and carO were seen in isolates of A. baumannii Tokai strain 2 (RRR), as assessed by real-time PCR. Thus, the molecular characterization of a series of isolates of DR A. baumannii revealed the outbreak of ST208 and diverse antimicrobial drug susceptibilities, which almost correlated with differential gene alterations responsible for each type of drug resistance.

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This study aimed to evaluate the effects of an ultraviolet (UV) curable coating material on denture base resin. The results of the three-point bending test showed no significant difference between treated and untreated specimens, suggesting that the UV curable coating material did not compromise the physical strength of denture base resin. The surface free energy measurement and the surface analysis with atomic force microscopy revealed superhydrophilicity and a regularly arranged structure on the coating surface, improving wettability. Moreover, untreated specimens were significantly discolored in the staining test. However, specimens treated with the UV curable coating material showed no significant difference in color with slight staining, suggesting excellent antifouling ability. Therefore, the UV curable coating material used in this study could contribute to simplifying hygiene without altering the physical properties of denture base resins.