Citations

ABSTRACT We tested the activity of anidulafungin against 30 Candida albicans isolates. The planktonic MICs for 50 and 90% of the isolates tested (MIC 50 and MIC 90 ) were ≤0.03 and 0.125 μg/ml, respectively (MIC range, ≤0.03 to 2 μg/ml). The sessile MIC 50 and MIC 90 were ≤0.03 and ≤0.03 μg/ml, respectively (MIC range, ≤0.03 to >16 μg/ml).

SUMMARYStaphylococcus lugdunensishas gained recognition as an atypically virulent pathogen with a unique microbiological and clinical profile.S. lugdunensisis coagulase negative due to the lack of production of secreted coagulase, but a membrane-bound form of the enzyme present in some isolates can result in misidentification of the organism asStaphylococcus aureusin the clinical microbiology laboratory.S. lugdunensisis a skin commensal and an infrequent pathogen compared toS. aureusandS. epidermidis, but clinically, infections caused by this organism resemble those caused byS. aureusrather than those caused by other coagulase-negative staphylococci.S. lugdunensiscan cause acute and highly destructive cases of native valve endocarditis that often require surgical treatment in addition to antimicrobial therapy. Other types ofS. lugdunensisinfections include abscess and wound infection, urinary tract infection, and infection of intravascular catheters and other implanted medical devices.S. lugdunensisis generally susceptible to antimicrobial agents and shares CLSI antimicrobial susceptibility breakpoints withS. aureus. Virulence factors contributing to this organism's heightened pathogenicity remain largely unknown. Those characterized to date suggest that the organism has the ability to bind to and interact with host cells and to form biofilms on host tissues or prosthetic surfaces.

The objective of this study was to assess growth patterns of hyperlipidemic children enrolled in a preventive cardiovascular health clinic. A retrospective chart review of hyperlipidemic children enrolled in the Mayo Clinic Cardiovascular Health Clinic for the Young was performed. All participants were counseled to eat an American Heart Association Step-One Diet and exercise regularly. Weight and height were measured every 3 months. Growth was assessed using attained heights and weights and body-mass index Z scores compared to standard distributions for North American children. Sixty-three patients (33 males and 30 females) were enrolled in the study. Mean age at clinic entrance was 7.8 ± 3.5 years (range: 2 to 16 years). We conclude that participation in a preventive health clinic is generally safe for hyperlipidemic children. However, medical management of hyperlipidemic children must include meticulous surveillance to detect the infrequent occurrence of excessive weight loss or weight stabilization resulting from inappropriate response to dietary counseling.

ABSTRACT Staphylococcus lugdunensis is a pathogen of heightened virulence that causes infections resembling those caused by Staphylococcus aureus rather than those caused by its coagulase-negative staphylococcal counterparts. Many types of S. lugdunensis infection, including native valve endocarditis, prosthetic joint infection, and intravascular catheter-related infection, are associated with biofilm etiology. Poly- N -acetylglucosamine (PNAG), a polysaccharide synthesized by products of the icaADBC locus, is a common mechanism of intercellular adhesion in staphylococcal biofilms. Here we report the characterization of ica homologues and the in vitro biofilm formation properties of a collection of S. lugdunensis clinical isolates. Isolates formed biofilms in microtiter wells to various degrees. Biofilm formation by most isolates was enhanced with glucose but diminished by sodium chloride or ethanol. icaADBC homologues were found in all S. lugdunensis isolates tested, although the locus organization differed substantially from that of other staphylococcal ica loci. icaR was not detected in S. lugdunensis , but a novel open reading frame with putative glycosyl hydrolase function is located upstream of the ica locus. icaADBC sequence heterogeneity did not explain the variability in biofilm formation among isolates. PNAG was not detected in S. lugdunensis extracts by immunoblotting with an anti-deacetylated PNAG antibody or wheat germ agglutinin. Confocal microscopy with fluorescently labeled wheat germ agglutinin showed a paucity of PNAG in S. lugdunensis biofilms, but abundant extracellular protein was visualized with SYPRO Ruby staining. Biofilms were resistant to detachment by dispersin B and sodium metaperiodate but were susceptible to detachment by proteases. Despite the genetic presence of icaADBC homologues in S. lugdunensis isolates, PNAG is not a major component of the extracellular matrix of in vitro biofilms formed by this species. Our data suggest that the S. lugdunensis biofilm matrix contains proteinaceous factors.

ABSTRACT Staphylococcus lugdunensis is an atypically virulent coagulase-negative staphylococcal species associated with acute and destructive infections that often resemble Staphylococcus aureus infections. Several types of infection caused by S. lugdunensis (e.g., native valve endocarditis, prosthetic joint infection, and intravascular catheter infection) are associated with biofilm formation, which may lead to an inability to eradicate the infection due to the intrinsic nature of biofilms to resist high levels of antibiotics. In this study, planktonic MICs and MBCs and biofilm bactericidal concentrations of 10 antistaphylococcal antimicrobial agents were measured for 15 S. lugdunensis isolates collected from patients with endocarditis, medical device infections, or skin and soft tissue infections. Planktonic isolates were susceptible to all agents studied, but biofilms were resistant to high concentrations of most of the drugs. However, moxifloxacin was able to kill 73% of isolates growing in biofilms at ≤0.5 μg/ml. Relative to the effect on cell density, subinhibitory concentrations of nafcillin substantially stimulated biofilm formation of most isolates, whereas tetracycline and linezolid significantly decreased biofilm formation in 93 and 80% of isolates, respectively. An unexpected outcome of MBC testing was the observation that vancomycin was not bactericidal against 93% of S. lugdunensis isolates, suggesting widespread vancomycin tolerance in this species. These data provide insights into the response of S. lugdunensis isolates when challenged with various levels of antimicrobial agents in clinical use.

ABSTRACT Staphylococci, common orthopedic pathogens, form antibiotic-resistant biofilms. Polymethylmethacrylate (PMMA) beads loaded with the quorum-sensing inhibitor RNAIII-inhibiting peptide (RIP) were implanted in rats and shown to prevent methicillin-resistant Staphylococcus aureus infection. RIP release was bimodal, typical of previously-tested antibiotics. These results suggest that RIP-PMMA warrants further evaluation for management of orthopedic infections caused by staphylococci.

ABSTRACT Conjunctival exposure to the Staphylococcus aureus superantigen staphylococcal enterotoxin B (SEB) may occur accidentally, as a result of bioterrorism, or during colonization or infection of the external eye. Using human leukocyte antigen class II transgenic mice, we show for the first time that conjunctival exposure to SEB can cause robust systemic immune activation.