Phenotypic and molecular methods were used to characterize the antibiotic resistance of 64 clinical isolates of Staphylococcus haemolyticus. By PCR of the mecA gene, 87% were found to be methicillin resistant. Approximately 55% harbored staphylococcal cassette chromosome mec element (SCCmec) type V, and only one SCCmec type IV. Many isolates (75%) displayed multiresistance, and pulsotype analysis showed a high diversity.A mong coagulase-negative staphylococci (CoNS), Staphylococcus haemolyticus is the second most frequently isolated from human blood cultures (18) and has the highest level of antimicrobial resistance (3,8). Methicillin resistance is conferred by the mecA gene, carried on the staphylococcal cassette chromosome mec element (SCCmec) (12). Eight types (I to VIII) of SCCmec have been assigned for Staphylococcus aureus (11), and SCCmec type V has already been found in CoNS, particularly in S. haemolyticus (13). The increase in the frequency of methicillinresistant S. haemolyticus as the causal agent of hospital infections and the possibility of emergence of resistance to other antibiotics demand trustworthy characterization of the isolates and an investigation of clonal spreading within hospitals.In the studies reported here, 64 clinical strains were isolated from patients at Hospital Naval Marcílio Dias, Rio de Janeiro, Brazil, between 2006 and 2008. The strains were isolated from the following clinical infections or sources in 31 males and 33 females: bacteremia (n ϭ 45), skin (n ϭ 2), urine (n ϭ 13), and unknown source (n ϭ 4). The isolates were identified at the hospital laboratory as S. haemolyticus by using the MicroScan WalkAway PC21 panel, and their identification was confirmed by specific PCR (17).The resistance profiles of the strains for the main antibiotics used in Brazil were determined by disc diffusion tests according to CLSI guidelines (5). However, the mupirocin susceptibility testing was not preconized by CLSI, so the results for this antibiotic were interpreted as previously described (7, 9). The methicillin resistance was also evaluated by other phenotypic methods, such as the MIC for oxacillin (5), the MicroScan, and PCR of the mecA gene (6). The SCCmec type was determined in a multiplex PCR as previously described (14), except that the pair of primers mecI P2 and mecI P3 used as the internal control were replaced by MRS1 and MRS2 (6), which amplify a 154-bp fragment of the mecA gene.Analysis of genetic relatedness and characterization of isolates using pulsed-field gel electrophoresis (PFGE) of genomic DNA digested with SmaI were carried out as previously described (20). Banding patterns were determined by visual inspection and by using Bionumerics software, version 6.0 (Applied Maths) using the Dice index and the unweighted-pair group method with arithmetic average. Similar PFGE genotypes were defined using a coefficient of similarity of up to 80%, and the subtypes were those with less than five-band variants, as recommended by van Belkun et al. (19).As shown in Table 1, there wa...

Previous studies showed that heart period decreases during and recovers after an acute stress. We investigated if individual predispositions and emotional priming influence heart period recovery after a speech stress task. Psychometric scales and resting cardiac vagal tone were used to measure individual traits. The presentation of a sequence of either pleasant or unpleasant pictures, as emotional primers, preceded the speech stress. Heart period was measured throughout the experiment. Stress induced tachycardia irrespective of emotional priming or traits. In the recovery period, participants with higher resting cardiac vagal tone or presenting higher resilience significantly reduced the heart acceleration. Furthermore, these traits interacted synergistically in the promotion of the recovery of heart period. Pleasant priming also improved recovery for participants with lower negative affect. In conclusion, the stress recovery measured through heart period seemed dependent upon individual predispositions and emotional priming. These findings further strengthen previous observations on the association between greater cardiac vagal tone and the ability to regulate emotion.

kIn Enterobacteriaceae, the bla NDM genes have been found in many different genetic contexts, and a wide diversity of plasmid scaffolds bearing those genes has been found. In August 2013, we identified NDM-1-producing Escherichia coli and Enterobacter hormaechei strains from a single rectal swab sample from a patient hospitalized in Rio de Janeiro, Brazil, who had no history of travel abroad. Complete DNA sequencing using the Illumina platform and annotation of the two plasmids harboring the bla NDM-1 gene, one from each strain, showed that they belonged to incompatibility groups IncFII K and IncX3 and harbored a novel transposon named Tn3000. Similar genetic structures have been identified among other isolates in Brazil but also on plasmids from other continents. Our findings suggest that the bla NDM-1 gene may be transmitted by Tn3000 in different parts of the world.

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Lipopeptide daptomycin is a last-line cell-membrane-targeting antibiotic to treat multidrug-resistant Staphylococcus aureus. Alarmingly, daptomycin-resistant S. aureus isolates have emerged. The mechanisms underlying daptomycin resistance are diverse and share similarities with resistances to cationic antimicrobial peptides and other lipopeptides, but they remain to be fully elucidated. We selected mutants with increased resistance to daptomycin from a library of transposon insertions in sequent type 8 (ST8) S. aureus HG003. Insertions conferring increased daptomycin resistance were localized to two genes, one coding for a hypothetical lipoprotein (SAOUHSC_00362, Dsp1), and the other for an alkaline shock protein (SAOUHSC_02441, Asp23). Markerless loss-of-function mutants were then generated for comparison. All transposon mutants and knockout strains exhibited increased daptomycin resistance compared to those of wild-type and complemented strains. Null and transposon insertion mutants also exhibited increased resistance to cationic antimicrobial peptides. Interestingly, the Δdsp1 mutant also showed increased resistance to vancomycin, a cell-wall-targeting drug with a different mode of action. Null mutations in both dsp1 and asp23 resulted in increased tolerance as reflected by reduced killing to both daptomycin and vancomycin, as well as an increased tolerance to surfactant (Triton X-100). Neither mutant exhibited increased resistance to lysostaphin, a cell-wall-targeting endopeptidase. These findings identified two genes core to the S. aureus species that make previously uncharacterized contributions to antimicrobial resistance and tolerance in S. aureus.

Staphylococcus haemolyticus is one of the most frequently isolated coagulase-negative staphylococci. The ability to produce biofilm has contributed to its emergence as a nosocomial pathogen. In this study, some growth conditions were tested to determine their influence on biofilm formation. Brain-heart infusion (BHI) broth containing glucose was used to screen 64 clinical strains. A strong biofilm producer strain showed cells surrounded by a thick layer of extracellular matrix. The presence of atlE, fbp, bap, and icaA genes was analyzed. We concluded that S. haemolyticus biofilm production can be increased with cells grown in BHI, and highlighted that it could be an ica-independent process.

This work is the first to show the production of biosurfactants by Staphylococcus haemolyticus strains. Extracts showed antimicrobial, anti-adhesive and synergistic properties against a variety of relevant human pathogens, including the producing strains. In addition to the biotechnological potential, biosurfactants produced by Staph. haemolyticus are potentially undescribed virulence determinants in their producing strains.

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