Long-term cortisol levels are not associated with nasal carriage of Staphylococcus aureus.
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ABSTRACT:
SUBMITTER: Manenschijn L
PROVIDER: S-EPMC3223589 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND: Colonization of humans with Staphylococcus aureus is a critical prerequisite of subsequent clinical infection of the skin, blood, lung, heart and other deep tissues. S. aureus persistently or intermittently colonizes the nares of approximately 50% of healthy adults, whereas approximately 50% of the general population is rarely or never colonized by this pathogen. Because microbial consortia within the nasal cavity may be an important determinant of S. aureus colonization we determined the composition and dynamics of the nasal microbiota and correlated specific microorganisms with S. aureus colonization. METHODOLOGY/PRINCIPAL FINDINGS: Nasal specimens were collected longitudinally from five healthy adults and a cross-section of hospitalized patients (26 S. aureus carriers and 16 non-carriers). Culture-independent analysis of 16S rRNA sequences revealed that the nasal microbiota of healthy subjects consists primarily of members of the phylum Actinobacteria (e.g., Propionibacterium spp. and Corynebacterium spp.), with proportionally less representation of other phyla, including Firmicutes (e.g., Staphylococcus spp.) and Proteobacteria (e.g. Enterobacter spp). In contrast, inpatient nasal microbiotas were enriched in S. aureus or Staphylococcus epidermidis and diminished in several actinobacterial groups, most notably Propionibacterium acnes. Moreover, within the inpatient population S. aureus colonization was negatively correlated with the abundances of several microbial groups, including S. epidermidis (p = 0.004). CONCLUSIONS/SIGNIFICANCE: The nares environment is colonized by a temporally stable microbiota that is distinct from other regions of the integument. Negative association between S. aureus, S. epidermidis, and other groups suggests microbial competition during colonization of the nares, a finding that could be exploited to limit S. aureus colonization.
| S-EPMC2871794 | biostudies-literature
Project description:Due to the increasing prevalence of nosocomial and community-acquired antibiotic resistant Staphylococcus aureus (SA), understanding the determinants of SA nasal carriage has become a major imperative. Previous research has revealed many host and bacterial factors that contribute to SA nasal carriage. To assess bacterial factors that facilitate nasal carriage, we compared the exoproteome of a nasal carrier strain of SA to a genetically similar noncarrier strain. Additionally, the carrier strain biofilm exoproteome was also compared against its planktonic counterpart. Using high throughput proteomics, it was observed that the carrier strain of SA secretes a greater number of proteins that may promote successful colonization of the human nose, including cell attachment and immunoevasive proteins, than the noncarrier strain. Similarly, SA carrier strain biofilm exoproteome contains a greater number of immunoevasive proteins than its planktonic counterpart. Analysis of the most abundant immunoevasive proteins revealed that Staphylococcal protein A was present at significantly higher levels in carrier than in noncarrier strains of SA, suggesting an association with nasal carriage. While further analyses of specific differences between carrier and noncarrier strains of SA are required, many of the differentially expressed proteins identified can be considered to be putative determinants of nasal carriage.
| S-EPMC3070068 | biostudies-other
Project description:INTRODUCTION: Staphylococcus aureus is the most important pathogen in the development of surgical site infections (SSI). Patients who carry S. aureus in the nose are at increased risk for the development of SSI in cardiothoracic and orthopedic surgery. In these populations it has been shown that the risk for SSI can be substantially reduced by eradicating S. aureus carriage. For vascular surgery the relation between nasal carriage and surgical site infections has not been clearly investigated. For this reason we performed this study to analyze the relation between S. aureus nasal carriage and SSI in our vascular surgery population. METHODS: A prospective cohort study was undertaken, including all patients undergoing vascular surgery between January first 2010 and December 31th 2010. Before surgery patients were screened for S. aureus nasal carriage using a PCR technique. The presence of SSI was recorded based on criteria of the CDC. RESULTS: Screening was performed in 224. Of those, 55 (24.5%) were positive, 159 (71.0%) were negative and 10 (4.5%) were inconclusive. In the screened vascular population 4 S. aureus SSI occurred in the 55 carriers compared with 6 in 159 non-carriers (p=0.24). A stratified analysis revealed a 10-fold increased risk in nasal carriers undergoing central reconstruction surgery (3 S. aureus SSI in 20 procedures versus 1 in 65 procedures in non-carriers, p=0.039). DISCUSSION: In patients undergoing central reconstruction surgery nasals carriers are at increased risk for the development of S. aureus SSI. These patients will probably benefit from perioperative treatment to eradicate nasal carriage.
| S-EPMC3369867 | biostudies-other
Project description:Objective. Chronic nasal carriage of Staphylococcus aureus (SA) increases the risk of relapse while Rituximab (RTX) is an effective agent for inducing and maintaining remission in patients with Granulomatosis with polyangiitis (GPA). We investigated whether B cell depletion and hypogammaglobulinemia that occur during RTX treatment increase the risk of chronic SA nasal carriage and subsequent disease flares, in GPA patients on long-term RTX maintenance therapy. Methods. Retrospective cohort study from a disease registry involving 29 GPA patients receiving RTX maintenance (median RTX dose of 9 g) during a median period of 49 months. Nasal swabs were collected prior and during RTX for a median of 3 and 9 swabs respectively. Persistent SA nasal carriage was defined with the presence of SA in more than 75% of nasal swabs. Results. SA nasal carriage did not change during RTX (p = 0.297). However, the rate of positive nasal swabs in GPA patients with transient SA nasal carriage during RTX maintenance increased from 0 prior RTX to 0.42 during RTX (p = 0.017). Persistent SA nasal carriage did not increase the risk of relapses (p = 0.844), of hypogammaglobulinemia (p = 0.122) and of severe infections (p = 0.144), but reduced the risk of chronic infections (p = 0.044). Change in SA carriage status during RTX did not influence the risk of relapses (p = 0.756), hypogammaglobulinamia (p = 0.474) and infections, either severe (p = 0.913) or chronic (p = 0.121). Conclusion. Long-term RTX maintenance therapy in GPA patients did not significantly influence SA nasal carriage status. Persistent SA carriage during long-term RTX treatment did not seem to increase the risk of relapses, but seemed to decrease the risk of hypogammaglobulinemia associated chronic infections.
| S-EPMC4485735 | biostudies-literature
Project description:BackgroundStaphylococcus aureus is a leading cause of healthcare- and community-associated infections and can be difficult to treat due to antimicrobial resistance. About 30% of individuals carry S. aureus asymptomatically in their nares, a risk factor for later infection, and interactions with other species in the nasal microbiome likely modulate its carriage. It is thus important to identify ecological or functional genetic elements within the maternal or infant nasal microbiomes that influence S. aureus acquisition and retention in early life.ResultsWe recruited 36 mother-infant pairs and profiled a subset of monthly longitudinal nasal samples from the first year after birth using shotgun metagenomic sequencing. The infant nasal microbiome is highly variable, particularly within the first 2 months. It is weakly influenced by maternal nasal microbiome composition, but primarily shaped by developmental and external factors, such as daycare. Infants display distinctive patterns of S. aureus carriage, positively associated with Acinetobacter species, Streptococcus parasanguinis, Streptococcus salivarius, and Veillonella species and inversely associated with maternal Dolosigranulum pigrum. Furthermore, we identify a gene family, likely acting as a taxonomic marker for an unclassified species, that is significantly anti-correlated with S. aureus in infants and mothers. In gene content-based strain profiling, infant S. aureus strains are more similar to maternal strains.ConclusionsThis improved understanding of S. aureus colonization is an important first step toward the development of novel, ecological therapies for controlling S. aureus carriage.
| S-EPMC7731505 | biostudies-literature
Project description:Inactivating mutations in the Staphylococcus aureus virulence regulator agr are associated with worse outcomes in bacteremic patients. However, whether agr dysfunction is primarily a cause or a consequence of early bacteremia is unknown. Analysis of 158 paired S. aureus clones from blood and nasal carriage sites in individual patients revealed that recovery of an agr-defective mutant from blood was usually predicted by the agr functionality of carriage isolates. Many agr-positive blood isolates produced low levels of hemolytic toxins, but levels were similar to those of colonizing strains within patients, suggesting that introduction into the blood did not select for mutations with minor functional effects. Evidently, the transition from commensalism to opportunism in S. aureus does not require full virulence in hospitalized patients. Furthermore, agr-defective mutants were found in uninfected nasal carriers in the same proportion as in carriers who develop bacteremia, suggesting low correlation between virulence and infectivity.
| S-EPMC3448967 | biostudies-literature
Project description:BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) is a major public health concern worldwide. Healthcare workers (HCWs) are an important source of transmission of MRSA. We conducted a prospective study to define the frequency of S. aureus nasal colonization with emphasis on the carriage of MRSA in HCWs in relation to the intensity of patient contact.MethodsOut-of-hospital care emergency medical technicians and students, and HCWs in the emergency department, intensive care unit and a long-term care facility (LTCF) were enrolled to compare the prevalence of MRSA and methicillin-susceptible S. aureus (MSSA) nasal colonization. The MRSA isolates were further identified by their microbiological and molecular characteristics.FindingsS. aureus was isolated from 63 of 248 HCWs (25.4%). The overall MRSA nasal carriage rate was 15/248, 6%, and the prevalence was higher in the HCWs who had worked for 5-10 years (12.8%), and among female HCWs (10.3%) than male HCWs (0.9%). LTCFs had the highest prevalence (12%). In contrast, the overall carriage of MSSA was 48/248, 19.4%, and most carriers worked for ≥5 years (52.1%). Hospital nurses had the highest rate of MSSA carriage (21.4%). Most of the MRSA isolates were SCCmec IV/ST59 or ST45 (60%), and were resistant to erythromycin and clindamycin (53%).ConclusionsHospital nurses have highest S. aureus nasal carriage, whereas HCWs in the LTCFs comprise a significant reservoir of MRSA colonization. The differences in the characteristics of MRSA and MSSA nasal carriage among HCWs highlights the importance on long-term nasal screening of S. aureus in healthcare facilities.
| S-EPMC8336196 | biostudies-literature
Project description:BackgroundNasal carriage of Staphylococcus aureus is a major risk factor in clinical and community settings due to the range of etiologies caused by the organism. We have identified unique immunological and ultrastructural properties associated with nasal carriage isolates denoting a role for bacterial factors in nasal carriage. However, despite extensive molecular level characterizations by several groups suggesting factors necessary for colonization on nasal epithelium, genetic determinants of nasal carriage are unknown. Herein, we have set a genomic foundation for unraveling the bacterial determinants of nasal carriage in S. aureus.ResultsMLST analysis revealed no lineage specific differences between carrier and non-carrier strains suggesting a role for mobile genetic elements. We completely sequenced a model carrier isolate (D30) and a model non-carrier strain (930918-3) to identify differential gene content. Comparison revealed the presence of 84 genes unique to the carrier strain and strongly suggests a role for Type VII secretion systems in nasal carriage. These genes, along with a putative pathogenicity island (SaPIBov) present uniquely in the carrier strains are likely important in affecting carriage. Further, PCR-based genotyping of other clinical isolates for a specific subset of these 84 genes raise the possibility of nasal carriage being caused by multiple gene sets.ConclusionOur data suggest that carriage is likely a heterogeneic phenotypic trait and implies a role for nucleotide level polymorphism in carriage. Complete genome level analyses of multiple carriage strains of S. aureus will be important in clarifying molecular determinants of S. aureus nasal carriage.
| S-EPMC2566312 | biostudies-literature
Project description:Nasal carriage with Staphylococcus aureus is a common risk factor for invasive infections, indicating the necessity to monitor prevalent strains, particularly in the vulnerable paediatric population. This surveillance study aims to identify carriage rates, subtypes, antimicrobial susceptibilities and virulence markers of nasal S. aureus isolates collected from children living in the Ashanti region of Ghana.Nasal swabs were obtained from children < 15 years of age on admission to the Agogo Presbyterian Hospital between April 2014 and January 2015. S. aureus isolates were characterized by their antimicrobial susceptibility, the presence of genes encoding for Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin-1 (TSST-1) and further differentiated by spa-typing and multi-locus-sequence-typing.Out of 544 children 120 (22.1%) were colonized with S. aureus, with highest carriage rates during the rainy seasons (27.2%; p = 0.007), in females aged 6-8 years (43.7%) and males aged 8-10 years (35.2%). The 123 isolates belonged to 35 different spa-types and 19 sequence types (ST) with the three most prevalent spa-types being t355 (n = 25), t84 (n = 18), t939 (n = 13), corresponding to ST152, ST15 and ST45. Two (2%) isolates were methicillin-resistant S. aureus (MRSA), classified as t1096 (ST152) and t4454 (ST45), and 16 (13%) were resistant to three or more different antimicrobial classes. PVL and TSST-1 were detected in 71 (58%) and 17 (14%) isolates respectively.S. aureus carriage among Ghanaian children seems to depend on age, sex and seasonality. While MRSA rates are low, the high prevalence of PVL is of serious concern as these strains might serve not only as a source for severe invasive infections but may also transfer genes, leading to highly virulent MRSA clones.
| S-EPMC5249101 | biostudies-other
Project description:Staphylococcus aureus (SA) nasal colonization plays a critical role in the pathogenesis of staphylococcal infections and SA eradication from the nares has proven to be effective in reducing endogenous infections. To understand SA nasal colonization and its relation with consequent disease, assessment of nasal carriage dynamics and genotypic diversity among a diverse population is a necessity.We have performed extensive longitudinal monitoring of SA nasal carriage isolates in 109 healthy individuals over a period of up to three years. Longitudinal sampling revealed that 24% of the individuals were persistent SA nasal carriers while 32% were intermittent. To assess the genetic relatedness between different SA isolates within our cohort, multi locus sequence typing (MLST) was performed. MLST revealed that not only were strains colonizing intermittent and persistent nasal carriers genetically similar, belonging to the same clonal complexes, but strain changes within the same host were also observed over time for both types of carriers. More highly discriminating genetic analyses using the hypervariable regions of staphylococcal protein A and clumping factor B virulence genes revealed no preferential colonization of specific SA strains in persistent or intermittent carriers. Moreover, we observed that a subset of persistent and intermittent carriers retained clinically relevant community-acquired methicillin-resistant SA (CA-MRSA) strains in their nares over time.The findings of this study provides added perspective on the nasal carriage dynamics between strains colonizing persistent and intermittent carriers; an area currently in need of assessment given that persistent carriers are at greater risk of autoinfection than intermittent carriers.
| S-EPMC3673815 | biostudies-other