Characterization of first hemin-requiring Pseudomonas aeruginosa small-colony variants from the blood of an octogenarian male-patient with double pneumonitis

Publication date: Available online 30 June 2017
Source:Journal of Infection and Chemotherapy
Author(s): Natsumi Nagano, Hideo Nakaya, Megumi Nagata, Toru Nishizawa, Ryuji Kawahara, Takehisa Matsumoto, Kozue Oana, Yoshiyuki Kawakami
A hemin-requiring Pseudomonas aeruginosa small-colony variant (SCV) was isolated from the blood of an octogenarian male-patient with double pneumonitis. The isolate was capable of growing on both sheep blood and chocolate agars but not on MacConkey agars without blood ingredient. Furthermore, the isolate revealed to grow only around the X-factor impregnated discs when examined using the X and V disc strips. However, not only RapID-NH system but also the VITEK2 system failed to identify the isolate. The isolate was finally identified as P. aeruginosa by the sequence of the 16S rRNA genes and the MALDI-TOF MS analysis. Interestingly, the isolate represented positive reaction for δ-aminolaevulinic acid (ALA)-test despite the requirement of hemin. Detailed analysis indicated that the isolate produced protoporphyrin IX from ALA. Therefore, the reason for the hemin dependence was deduced the dysfunction of hemH-encoded ferrochelatase behaving at the end of biosynthetic pathway of heme. However, the genetic analysis of hemH gene demonstrated no variations of both the DNA and the amino-acid sequences. To the best of our knowledge, this is the first clinical isolation of a hemin-dependent P. aeruginosa SCV from blood.



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