Dataset Information

High-level fluoroquinolone resistance in ophthalmic clinical isolates belonging to the species Corynebacterium macginleyi.

ABSTRACT: The clinical importance of nondiphtherial Corynebacterium, a ubiquitous member of the normal human microflora of the skin and mucous membrane, for ocular surface infections has been recognized recently. We performed an antimicrobial susceptibility test with Etest strips for three fluoroquinolones (ciprofloxacin, norfloxacin, and levofloxacin) and a taxonomic analysis on 21 isolates of Corynebacterium from ophthalmic samples. Of these, 16 isolates were identified as C. macginleyi at the species level on the basis of 16S rRNA gene sequence comparisons. The remaining five isolates were determined to be C. mastitidis (four) or C. accolens (one). Eleven of the C. macginleyi isolates showed high levels of resistance to all of the fluoroquinolones tested, and one isolate was resistant to norfloxacin alone. An analysis of the amplified quinolone-resistance-determining regions of the gyrA genes revealed that a single amino acid substitution in position 83 of the gyrA product was sufficient to generate the norfloxacin resistance phenotype, and double mutations leading to amino acid changes in positions 83 and 87 were necessary for high-level resistance against the other fluoroquinolones. We conducted the first example of multilocus sequence typing (MLST) analysis on C. macginleyi. The MLST analysis grouped the majority of C. macginleyi isolates into a single lineage, and another molecular strain typing by random amplified polymorphic DNA fragment patterns supported the finding, indicating that a particular lineage of C. macginleyi is dominant on the human ocular surface. This type of population might be particularly adaptable to the milieu on the human ocular surface.

SUBMITTER: Eguchi H

PROVIDER: S-EPMC2238091 | biostudies-literature | 2008 Feb

REPOSITORIES: biostudies-literature

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High-level fluoroquinolone resistance in ophthalmic clinical isolates belonging to the species Corynebacterium macginleyi.

Eguchi Hiroshi H Kuwahara Tomomi T Miyamoto Tatsuro T Nakayama-Imaohji Haruyuki H Ichimura Minoru M Hayashi Tetsuya T Shiota Hiroshi H

Journal of clinical microbiology 20071212 2

The clinical importance of nondiphtherial Corynebacterium, a ubiquitous member of the normal human microflora of the skin and mucous membrane, for ocular surface infections has been recognized recently. We performed an antimicrobial susceptibility test with Etest strips for three fluoroquinolones (ciprofloxacin, norfloxacin, and levofloxacin) and a taxonomic analysis on 21 isolates of Corynebacterium from ophthalmic samples. Of these, 16 isolates were identified as C. macginleyi at the species l ...[more]

PMID: 18077650

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Project description:Cassava brown streak disease (CBSD) is emerging as one of the most important viral diseases of cassava (Manihot esculenta) and is considered today as the biggest threat to cassava cultivation in East Africa. The disease is caused by isolates of at least two phylogenetically distinct species of single-stranded RNA viruses belonging to the family Potyviridae, genus Ipomovirus. The two species are present predominantly in the coastal lowland [Cassava brown streak virus (CBSV); Tanzania and Mozambique] and highland [Cassava brown streak Uganda virus (CBSUV); Lake Victoria Basin, Uganda, Kenya and Malawi] in East Africa. In this study, we demonstrate that CBSD can be efficiently controlled using RNA interference (RNAi). Three RNAi constructs targeting the highland species were generated, consisting of the full-length (FL; 894 nucleotides), 397-nucleotide N-terminal and 491-nucleotide C-terminal portions of the coat protein (CP) gene of a Ugandan isolate of CBSUV (CBSUV-[UG:Nam:04]), and expressed constitutively in Nicotiana benthamiana. After challenge with CBSUV-[UG:Nam:04], plants homozygous for FL-CP showed the highest resistance, followed by the N-terminal and C-terminal lines with similar resistance. In the case of FL, approximately 85% of the transgenic plant lines produced were completely resistant. Some transgenic lines were also challenged with six distinct isolates representing both species: CBSV and CBSUV. In addition to nearly complete resistance to the homologous virus, two FL plant lines showed 100% resistance and two C-terminal lines expressed 50-100% resistance, whereas the N-terminal lines succumbed to the nonhomologous CBSV isolates. Northern blotting revealed a positive correlation between the level of transgene-specific small interfering RNAs detected in transgenic plants and the level of virus resistance. This is the first demonstration of RNAi-mediated resistance to CBSD and protection across very distant isolates (more than 25% in nucleotide sequence) belonging to two different species: Cassava brown streak virus and Cassava brown streak Uganda virus.

Dataset Information

High-level fluoroquinolone resistance in ophthalmic clinical isolates belonging to the species Corynebacterium macginleyi.

Publications

High-level fluoroquinolone resistance in ophthalmic clinical isolates belonging to the species Corynebacterium macginleyi.

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