Julia Alcoba-Flórez

Phenotypic and Molecular Characterization of Candida nivariensis sp. nov., a Possible New Opportunistic Fungus

ABSTRACT The new species Candida nivariensis, isolated from the clinical samples of three patients in Spain over a 3-year period, is presented here. This species can be easily differentiated from Candida glabrata, the closest genetic species, by different colony color on CHROMagar and by its ability to ferment trehalose. The analyses of the internal transcribed spacer region and the D1-D2 region of the 26S rRNA gene sequences support a new species designation.

High-Level Mupirocin Resistance within Methicillin-Resistant Staphylococcus aureus Pandemic Lineages

ABSTRACT The methicillin-resistant Staphylococcus aureus (MRSA) population in the Hospital Universitario Nuestra Señora de Candelaria over a 5-year period (1998 to 2002) was marked by shifts in the circulation of pandemic clones. Here, we investigated the emergence of high-level mupirocin resistance (Hi-Mupr). In addition to clonal spread, transfer of ileS2-carrying plasmids played a significant role in the dissemination of Hi-Mupr among pandemic MRSA lineages.

PCR Protocol for Specific Identification of Candida nivariensis, a Recently Described Pathogenic Yeast

ABSTRACT Candida nivariensis is a recently described pathogenic yeast closely related to Candida glabrata. We developed a specific set of oligonucleotide primers based on the internal transcribed spacer regions of the rRNA gene for the rapid identification of C. nivariensis. PCR with these primers amplified a 206-bp amplicon from C. nivariensis.

Complete Nucleotide Sequence and Comparative Analysis of pPR9, a 41.7-Kilobase Conjugative Staphylococcal Multiresistance Plasmid Conferring High-Level Mupirocin Resistance

ABSTRACT We have sequenced the conjugative plasmid pPR9, which carries the ileS2 gene, which had contributed to the dissemination of high-level mupirocin resistance at our institution. The plasmid backbone shows extensive genetic conservation with plasmids belonging to the pSK41/pGO1 family, but comparative analyses have revealed key differences that provide important insights into the evolution of these medically important plasmids and high-level mupirocin resistance in staphylococci and highlight the role of insertion sequence IS257 in these processes.

Familial Furunculosis Associated with Community-Acquired Leukocidin-Positive Methicillin-Susceptible Staphylococcus aureus ST152

ABSTRACT Panton-Valentine leukocidin (PVL) is associated with staphylococcal skin and pulmonary infections. Community dissemination of PVL-producing Staphylococcus aureus strains constitutes a public health concern. Family transmission and spread of community-acquired leukocidin-positive methicillin-susceptible S. aureus ST152 isolates associated with severe clinical symptoms are herein described. Remarkably, ST152 isolates usually are methicillin resistant.

Changes in ciprofloxacin resistance levels in Enterobacter aerogenes isolates associated with variable expression of the aac(6')-Ib-cr gene.

ABSTRACT Two closely related Enterobacter aerogenes isolates presented a new identical aac(6′)-Ib-cr genetic environment, including IS26. One isolate showed lower MICs of ciprofloxacin, norfloxacin, tobramycin, and amikacin and decreased expression of aac(6′)-Ib-cr, which might be related to a 12-bp deletion causing a displacement of the −10 box upstream of the aac(6′)-Ib-cr gene.

PCR-based amplification of heterogeneous IS257-ileS2 junctions for molecular monitoring of high-level mupirocin resistance in staphylococci

OBJECTIVES Plasmids encoding the ileS2 gene are responsible for the wide spread of high-level mupirocin resistance in staphylococci, and consequent clinical and epidemiological problems. We investigated the location of insertion sequence IS257 flanking ileS2 in different plasmids and developed a method for molecular typing of the IS257-ileS2 spacer regions. METHODS Nine ileS2-encoding plasmids (i.e. pPR1-pPR9) classified into distinct structural groups (i.e. S1-S4) were analysed. Complete DNA sequences between IS257s flanking ileS2 were determined. A PCR-based amplification scheme was designed for the simultaneous amplification of up- and down-stream IS257-ileS2 regions. The method was applied to a total of 90 high-level mupirocin-resistant clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). RESULTS pPR1-pPR9 possessed IS257s flanking ileS2. Plasmids of each structural group showed a unique configuration of IS257-ileS2 spacer regions. The PCR-based method permitted accurate typing of the heterogeneous IS257-ileS2 up- and down-stream junctions, and the differentiation of plasmids of each group. The results obtained corresponded with previous plasmid typing based on restriction enzyme analyses and ileS2 locus hybridization polymorphs. The application of the PCR-based method to a diverse collection of MRSA isolates carrying ileS2-encoding plasmids demonstrated its versatility and revealed extraordinary heterogeneity in the IS257-ileS2 spacers. CONCLUSIONS The devised PCR-based scheme offers a rapid, simple and effective approach for typing IS257-ileS2 configurations present on ileS2-encoding plasmids. Hopefully, it could serve as a useful molecular epidemiological tool to control high-level mupirocin resistance.

Genetic diversity of community-associated methicillin-resistant Staphylococcus aureus isolated from Tenerife Island, Spain

With the recent detection of MRSA (methicillin-resistant Staphylococcus aureus) infections in patients lacking health care-related risk factors, the term community-acquired MRSA (CA-MRSA) has been become widely recognised. Many cases of CA-MRSA spreading to the community have been described worldwide. The aim of this study was to determine the features of CA-MRSA isolates from Tenerife Island. Toward this end, one hundred MRSA isolates were collected from eight different health regions, and their molecular features were investigated. This study revealed a wide variety of MRSA clones, including an emergent ST: ST1434 (CC8) and two new spa types, t7575 (ST125) and t7678 (ST22). The PVL genes were found in only five isolates belonging to unrelated lineages, ST8, ST30 and ST22, which could indicate at least three independent introductions of PVL(+) strains to Tenerife. Moreover, we detected that hospital MRSA clones, like EMRSA-15 and EMRSA-16, had spread to the community and are now circulating in both environments. Therefore, in our study, the CDCs rules were not specific enough to distinguish CA-MRSA from HA-MRSA. Thus, we think that the current epidemiological information is not enough to discriminate between both MRSAs, and it is necessary for prevention guidelines to include the routine determination of at least the genetic background, the antimicrobial susceptibility profile, and the PVL genes of each MRSA isolate.

Molecular characterization of Alternaria alternata causing ocular infection: detection of IGS-RFLP intraspecific polymorphism

A case of fungal keratitis is presented in which corneal scrapings were obtained for microbiological studies, including morphological identification and molecular characterization of the etiologic agent. Comparative sequence analyses of the Internal Transcribed Spacer domain of 5.8S and 26S regions of nuclear rDNA showed 100% identity with different species of Alternaria and PCR-RFLP analysis of Intergenic Spacer regions revealed intraspecific variation. The combination of morphological and molecular characters resulted in the unambiguous identification of the causal agent as Alternaria alternata. Treatment with antifungals contributed to the improvement in the patients lesions.

Lachancea lanzarotensis sp. nov., an ascomycetous yeast isolated from grapes and wine fermentation in Lanzarote, Canary Islands.

During the characterization of the microbiota biodiversity associated with grapes and wineries in different bioclimatic conditions of the Canary Islands (Spain), a novel yeast species was isolated from Lanzarote, the driest wine-producing region of the archipelago. Seven strains isolated from grapes, microvinifications and wineries are described. Sequence analysis of the D1/D2 domain of the LSU rDNA gene and 5.8S-ITS regions revealed that the isolates were phylogenetically a member of the genus Lachancea and are closely related to Lachancea meyersii NRRL Y-27269(T) and Lachancea nothofagi NRRL Y-48670(T). On the basis of morphological, biochemical and physiological characterization and phylogenetic analysis, a novel ascosporogenous yeast species, Lachancea lanzarotensis sp. nov., is proposed. The type strain is L2C-15(T) ( = CBS 12615(T) = CECT 13066(T)) which was isolated from grape berries of Vitis vinifera L. cv. Listán Negro red grape variety in Tinajo, Lanzarote. The MycoBank no. is MB 801390.