Distribution of capsular and surface polysaccharide serotypes of Staphylococcus aureus.

Because of its ability to cause serious and fatal infections, Staphylococcus aureus remains one of the most feared microorganisms. Methicillin-resistant S. aureus (MRSA) has long been a common pathogen in healthcare facilities, but within the past decade, it has emerged as a problematic pathogen in the community setting as well.

Systematic survey of nonspecific agglutination by Candida spp. in latex assays.

In order to demonstrate that cells of Candida spp. may show considerable nonspecific agglutination in latex agglutination tests, 150 clinical and reference isolates of 12 yeast species were systematically studied by applying various test parameters. In fact, 40 (26.

A quantitative real-time immuno-PCR approach for detection of staphylococcal enterotoxins.

Bacterial intoxications represent a substantial public health concern with enterotoxins produced by Staphylococcus aureus among the most common causes of food poisoning. In addition to their role in the pathogenicity of food poisoning, staphylococcal enterotoxins have profound effects on the immune system as members of the family of pyrogenic toxin superantigens. As the classical diagnostic bioassays as well as the routinely used immunological methods are hampered by several drawbacks regarding sensitivity, specificity, and practicability, there is a need for the timely identification of toxins by highly sensitive and specific methods.

Reporter metabolite analysis of transcriptional profiles of a Staphylococcus aureus strain with normal phenotype and its isogenic hemB mutant displaying the small-colony-variant phenotype.

In this study, full-genome DNA microarrays based on the sequence of Staphylococcus aureus N315 were used to compare the transcriptome of a clinical S. aureus strain with a normal phenotype to that of its isogenic mutant with a stable small-colony-variant (SCV) phenotype (hemB::ermB). In addition to standard statistical analyses, systems biology advances were applied to identify reporter metabolites and to achieve a more detailed survey of genome-wide expression differences between the hemB mutant and its parental strain.

Biotyping of enterotoxigenic Staphylococcus aureus by enterotoxin gene cluster (egc) polymorphism and spa typing analyses.

Thirty-five Staphylococcus aureus strains, including 10 reference strains and 25 strains recovered from clinical specimens and food samples, were analyzed by PCR REA (restriction endonucleases analysis) of the egc operon and spa typing. Nineteen spa types and seven different egc operons, including four putative new egc variants, were revealed. In 13 strains, allelic variants of sei and/or seg were found.

Fourier-transform infrared spectroscopic analysis is a powerful tool for studying the dynamic changes in Staphylococcus aureus small-colony variants.

Infections due to small-colony variants (SCVs) of Staphylococcus aureus in patients with chronic and recurrent infections are an emerging problem; however, studies with this subpopulation are hampered by the fact that SCVs may exhibit unstable phenotypes, making them difficult to study, particularly in broth media. In this study, two S. aureus sets comprising the (i) normal and the (ii) SCV phenotype (clonal with normal phenotype) recovered from clinical specimens, as well as (iii) corresponding site-directed mutants displaying the SCV phenotype (knockout of hemB) and (iv) their complemented mutants were examined by Fourier-transform infrared (FTIR) spectroscopy.

The small colony variant (SCV) concept -- the role of staphylococcal SCVs in persistent infections.

The recovery of small colony variants (SCVs) from clinical specimens was first described at the beginning of the last century. However, not until the past decade was an association of these variants with chronic, recurrent, and persistent infections such as chronic osteomyelitis and persistent skin and softtissue infection described. Since then, a number of reports and prospective studies have supported a pathogenic role for SCVs in disease.

Small colony variants: a pathogenic form of bacteria that facilitates persistent and recurrent infections.

Small colony variants constitute a slow-growing subpopulation of bacteria with distinctive phenotypic and pathogenic traits. Phenotypically, small colony variants have a slow growth rate, atypical colony morphology and unusual biochemical characteristics, making them a challenge for clinical microbiologists to identify. Clinically, small colony variants are better able to persist in mammalian cells and are less susceptible to antibiotics than their wild-type counterparts, and can cause latent or recurrent infections on emergence from the protective environment of the host cell.

Sequencing and staphylococci identification.

The emerging clinical importance of staphylococcal infections prompted us to establish a reference database for partial RNA polymerase B (rpoB; nucleotides 1444-1928) gene sequences from type strains of all staphylococcal species and subspecies. This database correctly identified 55 clinical staphylococcal isolates; all were correctly identified at the species level. At the subspecies level, rpoB misidentified only 2 isolates.

Does nasal cocolonization by methicillin-resistant coagulase-negative staphylococci and methicillin-susceptible Staphylococcus aureus strains occur frequently enough to represent a risk of false-positive methicillin-resistant S. aureus determinations by molecular methods?

By analyzing the colonization of the anterior nares in cardiothoracic surgery patients on admission, nasal cocolonization by methicillin-susceptible Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci was detected in 8/235 (3.4%) specimens. Consequently, in a low-methicillin-resistant S.

Phenotype microarray profiling of Staphylococcus aureus menD and hemB mutants with the small-colony-variant phenotype.

Standard biochemical tests have revealed that hemin and menadione auxotrophic Staphylococcus aureus small-colony variants (SCVs) exhibit multiple phenotypic changes. To provide a more complete analysis of the SCV phenotype, two genetically defined mutants with a stable SCV phenotype were comprehensively tested. These mutants, generated via mutations in menD or hemB that yielded menadione and hemin auxotrophs, were subjected to phenotype microarray (PM) analysis of over 1,500 phenotypes (including utilization of different carbon, nitrogen, phosphate, and sulfur sources; growth stimulation or inhibition by amino acids and other nutrients, osmolytes, and metabolic inhibitors; and susceptibility to antibiotics).

Comparative in vitro activity of ceftobiprole against staphylococci displaying normal and small-colony variant phenotypes.

The antistaphylococcal activity of ceftobiprole was compared with those of cefuroxime, linezolid, and moxifloxacin by using the agar dilution method. Apart from three strains with small-colony variant phenotypes, all Staphylococcus aureus isolates tested were inhibited by < or =2 microg/ml of ceftobiprole. This compound exhibited an excellent antistaphylococcal activity, comparable to that of linezolid.

Staphylococcus lugdunensis pacemaker-related infection.

We report the first known case of a device-related bloodstream infection involving Staphylococcus lugdunensis small-colony variants. Recurrent pacemaker-related bloodstream infection within a period of 10 months illustrates the poor clinical and microbiologic response even to prolonged antimicrobial drug therapy in a patient infected with this staphylococcal subpopulation.

Evaluation of two chromogenic agar media for recovery and identification of Staphylococcus aureus small-colony variants.

To identify the most rapid and reliable technique for recovery and identification of Staphylococcus aureus small-colony variants (SCVs), the colonial appearance of 106 isolates representing SCVs and the normal phenotype were evaluated on two newly described chromogenic agar media. Although almost all of the SCVs grew on the chromogenic agar media, they did not exhibit a change of color. In comparison with conventional media, S.

Thermonuclease gene as a target for specific identification of Staphylococcus intermedius isolates: use of a PCR-DNA enzyme immunoassay.

A PCR-DNA enzyme immunoassay (PCR-DEIA) was developed for identification of the coagulase-positive species Staphylococcus intermedius. Two PCR primers and a hybridization probe were designed to target specific sequences of the S. intermedius thermonuclease (nuc) gene.

Real-time quantitative PCR assay for the detection of Helicobacter pylori: no association with sudden infant death syndrome.

Helicobacter pylori infection is known to be one of the most common chronic infectious diseases in humans. Recently, a hypothesis was proposed that H. pylori infection could be a frequent cause for sudden infant death syndrome (SIDS).

Impact of a molecular approach to improve the microbiological diagnosis of infective heart valve endocarditis.

Background: Even today, infective endocarditis (IE) remains a severe and potentially fatal disease demanding sophisticated diagnostic strategies for detection of the causative microorganisms. Despite the use of appropriate laboratory techniques, classic microbiological diagnostics are characterized by a high rate of negative results.

Methods And Results: Broad-range polymerase chain reaction (PCR) targeting bacterial and fungal rDNA followed by direct sequencing was applied to excised heart valves (n=52) collected from 51 patients with suspected infectious endocarditis and from 16 patients without any signs of IE during an 18-month period.

Infections associated with medical devices: pathogenesis, management and prophylaxis.

The insertion or implantation of foreign bodies has become an indispensable part in almost all fields of medicine. However, medical devices are associated with a definitive risk of bacterial and fungal infections. Foreign body-related infections (FBRIs), particularly catheter-related infections, significantly contribute to the increasing problem of nosocomial infections.

Development and evaluation of a quality-controlled ribosomal sequence database for 16S ribosomal DNA-based identification of Staphylococcus species.

To establish an improved ribosomal gene sequence database as part of the Ribosomal Differentiation of Microorganisms (RIDOM) project and to overcome the drawbacks of phenotypic identification systems and publicly accessible sequence databases, both strands of the 5' end of the 16S ribosomal DNA (rDNA) of 81 type and reference strains comprising all validly described staphylococcal (sub)species were sequenced. Assuming a normal distribution for pairwise distances of all unique staphylococcal sequences and choosing a reporting criterion of > or =98.7% similarity for a "distinct species," a statistical error probability of 1.

Systematic survey on the prevalence of genes coding for staphylococcal enterotoxins SElM, SElO, and SElN.

Staphylococcus aureus remains a leading cause of food-poisoning with substantial impact on public health. Using a multiplex polymerase chain reaction-DNA enzyme immunoassay (PCR-DEIA), we studied the presence of genes encoding staphylococcal enterotoxin-like (SEl) superantigens sem, sen, and seo, associated with the enterotoxin gene cluster (egc), in 429 clinical Staphylococcus aureus isolates. 294 (68.

Cellular prion protein acquires resistance to proteolytic degradation following copper ion binding.

The conversion of cellular prion protein (PrP(C)) into its pathological isoform (PrP(Sc)) conveys an increase in hydrophobicity and induces a partial resistance to proteinase K (PK). Interestingly, co-incubation with high copper ion concentrations also modifies the solubility of PrP(c) and induces a partial PK resistance which was reminiscent of PrP(Sc). However, concerns were raised whether this effect was not due to a copper-induced inhibition of the PK itself.

Prevalence of genes encoding for members of the staphylococcal leukotoxin family among clinical isolates of Staphylococcus aureus.

Well-characterized Staphylococcus aureus nasal and blood isolates (N = 429) were tested by polymerase chain reaction for the prevalence of genes that encode leukocidal toxins. The leukotoxin genes lukE+lukD were found at high prevalence, significantly more so in blood (82%) than in nasal isolates (60.5%).

Effect of trimethoprim-sulfamethoxazole prophylaxis in AIDS patients on the formation of the small colony variant phenotype of Staphylococcus aureus.

Emergence of Staphylococcus aureus small colony variants (SCVs) has been associated with antibiotic use, particularly with trimethoprim-sulfamethoxazole (TMP-SMZ). In this study, 634 specimens of 125 patients with AIDS were prospectively screened for S. aureus with normal phenotype and for S.

Evaluation of different methods to detect methicillin resistance in small-colony variants of Staphylococcus aureus.

To evaluate different methods for their abilities to detect methicillin resistance in small-colony variants (SCVs) of Staphylococcus aureus, 11 different methicillin-resistant S. aureus (MRSA) clones with the SCV phenotype were used in this study. The slow growth of SCVs often makes testing by disk diffusion or by automated methods invalid.