First reported isolation of hemin-requiring Proteus vulgaris small-colony variant from urine culture.

A hemin-requiring Proteus vulgaris small-colony variant (SCV) was isolated from a urine culture. This isolate was grown on 5% sheep blood agar but not on modified Drigalski agar. The single nucleotide substitution was found in the SCV of the hemC gene (c.55C > T), and this substitution caused a nonsense mutation (p.Gln19Ter). Porphyrin test results showed that the biosynthesis of δ-aminolevulinic acid stopped up to porphobilinogen and not pre-uroporphyrinogen due to a mutation in the hemC gene. To our knowledge, this is the first report of hemin-requiring P. vulgaris.

[Evaluation of Methicillin Resistance Determination Time for MRSA Using Fully Automated Rapid Identification Susceptibility testing system RAISAS S4].

In this study, we examined the accuracy and rapidity of drug susceptibility determination using clinical isolates of MRSA with the fully automated rapid identification susceptibility testing system RAISUS S4. Ninety eight MRSA strains were used and the time until methicillin resistance was determined was analyzed by both of the standard method (18-hr method) and the rapid method. Five strains (5.1%) were determined to be methicillin-sensitive in MPIPC by rapid method only while all strains were determined to be resistant in CFX. The average methicillin resistance determination time was 7.0/5.0 hr for MPIPC, 6.3/5.0 hr for CFX, and 6.3/5.0 hr for the combination of MPIPC and CFX by the standard/rapid method, with the rapid method being significantly shorter (Wilcoxon's signed rank sum test, p<0.01). Strains determined to be methicillin-sensitive by MPIPC tended to have a longer time to methicillin resistance by the standard method, but this effect was much less pronounced for the rapid method using CFX. Methicillin resistance determination by the rapid method using RAISUS S4 enables rapid detection of MRSA without false-susceptible results, which may lead to early and appropriate treatment.