Nasal Staphylococcus Aureus Carriage Research Articles

Association of Staphylococcus aureus Bacterial Load and Colonization Sites With the Risk of Postoperative S. aureus Infection.

The independent effects of extranasal-only carriage, carriage at multiple bodily sites, or the bacterial load of colonizing Staphylococcus aureus (SA) on the risk of developing SA surgical site infections and postoperative bloodstream infections (SA SSI/BSIs) are unclear. We aimed to quantify these effects in this large prospective cohort study. Surgical patients aged 18 years or older were screened for SA carriage in the nose, throat, or perineum within 30 days before surgery. SA carriers and noncarriers were enrolled in a prospective cohort study in a 2:1 ratio. Weighted multivariable Cox proportional hazard models were used to assess the independent associations between different measures of SA carriage and occurrence of SA SSI/BSI within 90 days after surgery. We enrolled 5004 patients in the study cohort; 3369 (67.3%) were SA carriers. 100 SA SSI/BSI events occurred during follow-up, and 86 (86%) of these events occurred in SA carriers. The number of colonized bodily sites (adjusted hazard ratio [aHR], 3.5-8.5) and an increasing SA bacterial load in the nose (aHR, 1.8-3.4) were associated with increased SA SSI/BSI risk. However, extranasal-only carriage was not independently associated with SA SSI/BSI (aHR, 1.5; 95% CI, 0.9-2.5). Nasal SA carriage was associated with an increased risk of SA SSI/BSI and accounted for the majority of SA infections. Higher bacterial load, as well as SA colonization at multiple bodily sites, further increased this risk.

Individual decontamination measures reduce by two the incidence of surgical site infections in spinal surgery

BackgroundIn spinal surgery, incidence of surgical site infections (SSI) is estimated between 1 and 10%. It results in increased morbidity, mortality and cost of management. Individual Staphylococcus aureus (SA) decolonization has already proved efficiency to prevent those events in various surgical domains. The aim of this study was to evaluate a strategy of prevention of SSI and in particular the decolonization of the nasal carriage of SA by a protocol with Mupirocin application. MethodsWe conducted a bicentric observational study on 5314 spinal surgery patients over a seven-year period. In both center, we compared periods before and after implementation of two measures: modification of antibioprophylaxis and staphylococcus decolonization. Homogeneity of the different samples of patients was assessed through measure of individual and surgical variables. We measured monthly incidence of SSI and evaluated its evolution in order to assess efficiency of these interventions. ResultsThe incidence of SSI decreased by half, from 7.3% to 3% at the Beaujon Hospital and from 8.3% to 3.9% at the Georges-Pompidou European Hospital (GPEH). We do not observe any significant decrease of SA rate in these SSI. ConclusionWe believe that Staphylococcus aureus decolonization should be recommended in spinal surgery, and should be combined with an overall improvement of the quality of care.

Nasal Colonization by Staphylococci and Severity of Atopic Dermatitis.

Skin colonization by Staphylococcus aureus (SA) correlates with increased severity of atopic dermatitis (AD). The role of nasal SA carriage and coagulase-negative staphylococci (CNSs) in AD is unclear. The aim of this study was to assess the influence of colonization of lesional/nonlesional skin and the anterior nares by SA and CNSs on AD severity in 63 adult patients. Disease severity was assessed with SCORAD index. The total immunoglobulin E (IgE) concentration was determined using the enzyme-linked immunosorbent assay method. The prevalence and abundance of staphylococci were assessed with the combination of bacterial culture and mass spectrometry. The prevalence values of SA within the skin (lesional/nonlesional) and anterior nares were 79.4%/61.9% and 69.8%, respectively (vs 5.6% and 13.9%, respectively in controls, P < 0.0001). The carriage of CNSs in all niches was associated with lower mean IgE concentration (1164.66 ± 1010.36 vs 1762.99 ± 1059.15, P < 0.0213; 1166.9 ± 1006.4 vs 2152.7 ± 759.2, P < 0.0063; 1022 ± 1100 vs 1925 ± 880.8, P < 0.0044, respectively). The abundance of SA correlated with the extent of skin lesions and total IgE (ρ = 0.42, P = 0.0007; ρ = 0.488, P < 0.0001; ρ = 0.312, P < 0.2; and ρ = 0.402, P = 0.0007; ρ = 0.403, P < 0.002; ρ = 0.287, P < 0.03, respectively). Atopic dermatitis severity correlates with both cutaneous and nasal colonization by SA. Staphylococcus aureus seems to promote TH2-type response, whereas CNS probably limits this process. Preventive measures within the anterior nares should be considered for AD patients.

No evident association of nasal carriage of Staphylococcus aureus or its small-colony variants with cotrimoxazole use or ANCA-associated vasculitis relapses.

To identify the role of Staphylococcus aureus (SA) or its intracellular small-colony variant phenotype (SCV) with co-trimoxazole (CTX) or ANCA-associated vasculitis (AAV) activity. All consecutive AAV patients with granulomatosis with polyangiitis (GPA), eosinophilic GPA or microscopic polyangiitis, followed at the French National Vasculitis Referral Center (09/2012-05/2013), and hospitalized non-AAV controls, exclusively for SA/SCV carriage comparisons, were enrolled. All had bilateral anterior nasal swab cultures. Nasal SA or SCV carriage was determined and associations with relapse(s), BVAS, ANCA-positivity, anti-staphylococcal and immunosuppressant use, were analysed ⩾4 years post-inclusion. Nasal SA carriage rates did not differ among AAVs (P = 0.53): GPA (24/80; 30%), EGPA (7/28; 25%) and microscopic polyangiitis (3/11; 27.3%); and the rate was less frequent in controls than in GPA patients not taking CTX (P = 0.04). AAV patients taking CTX prophylaxis had less nasal SA carriage (8.7% vs 36.2%; P = 0.02). Nasal SA carriage or CTX use did not modify relapse rates, BVAS or ANCA-positivity at inclusion or during follow-up. Nasal SCV carriage, found in 15/207 (7.2%) patients, was similar for GPA (10/24; 41.7%), microscopic polyangiitis (2/7; 28.6%) and eosinophilic GPA (2/3; 66.7%), but higher (P = 0.02) than controls (1/14; 7.1%). SCV carriage by AAV groups did not modify relapse rates or ANCA positivity at inclusion or during follow-up; a trend towards higher BVAS was observed only for anti-PR3 ANCA patients. Nasal SA or SCV carriage was comparable among AAVs but more frequent than in controls. Nasal SA or SCV carriage and CTX use did not modify AAV relapse rates.

Chronic nasal Staphylococcus aureus carriage identifies a subset of newly diagnosed granulomatosis with polyangiitis patients with high relapse rate.

The aim of this study was to evaluate whether chronic nasal carriage of Staphylococcus aureus (SA) is related to relapses in patients with newly diagnosed ANCA-associated vasculitis (AAV). In two clinical trials (n = 200), for early systemic (n = 83) and generalized (n = 117) AAV, nasal swabs were obtained monthly and at the time of a relapse. Chronic nasal SA carriage (CNSAC) was defined as ⩾ 75% of cultures being SA positive, with non-carriers being SA negative in all cultures and remaining patients being intermittent carriers. Fifty-five of 200 (27.5%) patients received prophylactic trimethoprim/sulfamethoxazole (T/S) against Pneumocystis jirovecii . Of the total AAV patients, 24/200 (12%) were chronic, 102/200 (51%) intermittent and 74/200 (37%) non-carriers. Of 65 relapsing patients, 10/24 (41.7%) were chronic, 32/102 (31.4%) intermittent and 23/74 (31.1%) non-carriers (P = 0.59). For all AAV patients, CNSAC was not associated with an increased relapse risk [odds ratio (OR) = 1.57, 95% CI: 0.66, 3.76; P = 0.31]. However, 23/24 chronic carriers had granulomatosis with polyangiitis (GPA). In the 73 patients with generalized GPA (hazard ratio = 4.10, 95% CI: 1.37, 12.25; P = 0.01) and the 78 patients with early systemic GPA during immunosuppression (hazard ratio = 2.73, 95% CI: 0.95, 7.87; P = 0.06), relapse rates were higher for chronic SA carriers. Prophylactic T/S was not associated with a reduced relapse risk (OR = 0.71, 95% CI: 0.36, 1.41; P = 0.33). Nevertheless, prophylactic T/S reduced CNSAC (OR = 0.19, 95% CI: 0.04, 0.91; P = 0.04). The frequency of CNSAC in newly diagnosed GPA paralleled that in the general population. This subset of GPA patients (23/151, 15.2%) has a high relapse rate despite immunosuppression and prophylactic T/S treatment, requiring further investigations on pathogenesis and therapy.

Nasal carriage frequency of Staphylococcus aureus according to education years of medical students

Objective: Nasal carriage of Staphylococcus aureus (NCSa) is one of the most important risk factors for nosocomial infection. Although there are numerous studies concerning NCSa frequency among medical staff, studies dealing specifically with medical students are less common. We aimed to investigate NCSa frequency among medical students and to compare the rates of clinical students (CS), comprising interns and stagers, with those of preclinical students (PS). Materials and Methods: This study was performed at Sakarya University Medical School. All students were invited to participate into the study. Nasal swab samples were taken anterior nares from 146 medical students (PS=82, CS=64). The samples were inoculated into the Chapman agar medium, and incubated at 370 C for 48 hours. Antibiotic sensitivity tests were performed on these colonies. The obtained data were analyzed statistically. Chi-square test was used for qualitative variables and t test was used as quantitative data. P <0.05 was considered significant. Results: A total of 146 students were agreed to participate in the study (53 subjects were male and 93 were female). While NCSa frequency within the PS group was 2/82 (2.4%), that within the CS group was 7/64 (10.9%) (p=0.042). Methicillin resistance was not detected in any subject. Conclusion: As a result, the frequency of NCSa in the CS group (10.9%) was found to be about 4 times higher than that in the PS group (2.4%). We recommend that clinical students should be expected to observe infection-control precautions. J Microbiol Infect Dis 2016; 6(3): 103-106

FRI0468 Chronic Nasal Carriage of Staphylococcus Aureus Does not Increase the Risk of Relapse and Severe Infections in Granulomatosis with Polyangiitis Patients When Receiving Rituximab Maintenance Treatment

BackgroundChronic nasal carriage of Staphylococcus aureus (SA) has been shown to increase the risk of relapse in patients with Granulomatosis with polyangiitis (GPA). B cell depletion with Rituximab (RTX) is...

Clonal Dynamics of Nasal Staphylococcus aureus and Staphylococcus pseudintermedius in Dog-Owning Household Members. Detection of MSSA ST398

The objective of this study was to investigate the dynamics of nasal carriage by Staphylococcus aureus (SA) and Staphylococcus pseudintermedius (SP) among healthy dog-owning household members involved in 7 previous index cases of suspected anthropozoonotic (n = 4) and zoonotic (n = 3) interspecies transmission [4 direct cases, identical SA (n = 3) or SP (n = 1) in owner and dog; three indirect, SP in owner (n = 2) or SA in dog (n = 1)]. Co-carriage with methicillin-resistant coagulase-negative staphylococci (MRCoNS) was also evaluated. Sixteen owners and 10 dogs were sampled once every three months for one year. In total, 50 SA and 31 SP were analysed by MLST, and SA also by spa typing. All isolates were subjected to ApaI/SmaI-PFGE and antimicrobial resistance and virulence profiles were determined. All index owners were persistent SA carriers in all direct-anthropozoonotic transmission cases, while only one dog was persistent SA carrier. Owner and dog exhibited a persistent SP carriage status in the direct-zoonotic transmission case. SP was maintained in the index human over time in one indirect-zoonotic transmission case. Only one SP was methicillin-resistant. SA belonged to genetic backgrounds of MRSA pandemic clones: CC45, CC121, CC30, CC5 and CC398. Three individuals carried a MSSA t1451-ST398 clone with the erm(T)-cadD/cadX resistance genes. SA or SP were persistently detected in the nasal cavity of 7 (43.8%) and 2 (12.5%) owners, and in one and 2 dogs, respectively. SA was recovered as the single species in 10 owners and in one dog; SP in 3 owners and 4 dogs; and both bacterial species in one owner and 4 dogs. Co-carriage of SA or SP with MRCoNS isolates was common (30.7%). This is the first study on the dynamics of nasal carriage of SA and SP in healthy pet-owning household members. Dog-contact may play a role in the staphylococcal species distribution of in-contact individuals.

Staphylococcus aureus protein A mediates innate immune responses during nasal colonization in humans (49.25)

Abstract Mucosa of the anterior human nares can harbor Staphylococcus aureus (SA), an etiologic agent that causes severe infections. Nasal carriage of SA is a complex host-pathogen interaction involving bacterial and host mediators that influence innate host defenses. We have revealed that the exoproteome of SA nasal carrier strains contains unique determinants, which enable SA to colonize the nares. In the current study, we assess how one of these bacterial mediators, Staphylococcal protein A (Spa), affects host innate immune response to SA nasal carriage. Functional disruption of spa was performed in an SA nasal carrier strain using Targetron insertion of a group II intron. Subsequent in vitro growth kinetics analysis and ex vivo culture on human nasal epithelial cells (HNECs) revealed no differences between wild type and spa-disrupted (Δspa) SA strains. However, the Δspa mutant induced lower expression of pro-inflammatory cytokines including IL6, IL8 and TNFα from HNECs compared to the levels elicited by the wild type strain. Additionally, IL17, a crucial regulator of mucosal immunity, was induced at significantly lower levels in HNECs inoculated with Δspa SA compared to those inoculated with the wild type SA strain. Furthermore, expression of the chemokines MIP1β and MCP1, as well as HL60 neutrophil migration, were significantly reduced in conditioned media from HNECs inoculated with Δspa mutants. Spa is likely involved in mediating the mucosal response to SA colonizing the nose.

Nasal Carriage of Methicillin-Resistant and Methicillin-Sensitive Strains of Staphylococcus sciuri in the Indonesian Population

Staphylococcus sciuri strains were unexpectedly cultured from healthy persons and patients from Indonesia during a population-based survey on nasal Staphylococcus aureus carriage. Fifty-one S. sciuri isolates were further characterized. The S. aureus mecA gene was detected by PCR in 22 isolates (43.1%), whereas S. sciuri mecA was found in 33 isolates (64.7%). The staphylococcal cassette chromosome mec (SCCmec) regions of S. aureus mecA-positive isolates contained elements of classical S. aureus SCCmec types II and/or III.

Nasal carriage of Staphylococcus aureus in children with allergic rhinitis and the effect of intranasal fluticasone propionate treatment on carriage status

The aim of this study is to determine the rate of nasal carriage of Staphylococcus aureus (NCSA) in children with allergic rhinitis (AR) and to determine the effect of intranasal fluticasone propionate spray on the NCSA. Nasal swabs were taken from the children admitted to general pediatrics and pediatric pulmonology clinics. Patients were divided into two groups according to the presence or absence of AR. Diagnosis of AR was based on the patient's symptoms. Nasal swabs were taken from AR patients before and after the treatment with intranasal fluticasone propionate, and from the control group at the beginning and after 2 months. Whole NCSA rate was 17.9%; it was 21.4% for AR patients and 15.9% for control group, respectively (p>0.05). Treatment with intranasal fluticasone propionate spray did not influence NCSA in AR patients. It seemed that NCSA was not increased in children with AR and treatment with intranasal fluticasone propionate spray did not change NCSA in AR patients. It is obvious that better understanding of the factors affecting the acquisition and loss of NCSA might increase our knowledge about the relationship between NCSA, allergic airway diseases and their treatments.

Nasal carriage of methicillin-resistant and methicillin-susceptible Staphylococcus aureus in nursing home residents in Bolu,Turkey

This study aimed (a) to provide information on methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus colonization ratio in residents of nursing homes; (b) to determine the effect of hand-washing education given to nursing home residents and employees on nasal carriage of Staphylococcus aureus (NCSA) and (c) to obtain probable risk factors for MRSA colonization of residents in two nursing homes. Seventy-nine volunteers (24 females and 55 males) from Bolu nursing homes were included in the study. Nasal samples were taken with sterile swabs from the anterior nares. Staphylococcus aureus strains were identified using classical methods and genotyping of methicillin resistant strains was done using Arbitrary Primed PCR (AP-PCR). Antibiotic susceptibilities were determined by disk diffusion methods according to NCCLS standards. After first nasal samples were taken, all employees and residents of nursing homes were educated about the methods of hand hygiene over two days. With hand-washing education, the decrease of NCSA rate (initially 43%; after education, 21%) was significant (p < 0.05) while decrease of MRSA carriage (initially 5%, after education 1%) was not (p > 0.05). MRSA carriage was significantly correlated with presence of skin lesions, prior hospitalization within the last six months, and antibiotics usage within the last six months. AP PCR results suggested that residents' carriage of MRSA was the result of the same source. MSSA and MRSA colonization rates were found to be 38% and 5% in nursing homes, respectively. These ratios can decrease with simple precautions like hand-washing after a short education period

The Effect of Triamcinolone Acetonide Aqueous Nasal Spray on the Nasal Carriage of Staphylococcus Aureus

In this study we aimed to investigate the effect of triamcinolone acetonide aqueous (TAA) intranasal spray that was used for 2 months to treat allergic rhinitis (AR) on the nasal carriage of Staphylococcus aureus (NCSA). A total of 125 adult AR patients (study group) and 133 healthy individuals (control group) were enrolled for the study. The subjects were diagnosed with AR after a detailed history, physical examination, and prick testing. The AR subjects were administered TAA in a daily dosage of a 220-microg intranasal route. Nasal cultures were obtained on the 1st (baseline), 55th, and 60th days, and the subjects in the last two cultures of whom S. aureus was detected were accepted as NCSA. After all exclusion criteria were used, 110 AR and 114 control group subjects were enrolled in the study. Based on the culture results that were obtained on the 55th and 60th days, 10 (%9.1) patients from the study group and 18 (%15.7) individuals from the control group were defined to be NCSA (p > 0.05). We conclude that the use of TAA treatment for AR does not increase the prevalence of NCSA. However, additional studies with a larger series are required to explain the effects of steroids on nasal colonization of S. aureus.

Nasal carriage of Staphylococcus aureus in house dust mite allergic patients and healthy controls

Staphylococcal colonization may influence the course of allergic diseases such as atopic dermatitis or allergic rhinitis. The frequency of Staphylococcus aureus (SA) nasal carriage and its possible influence on persistent allergic rhinitis was investigated. In nasal lavages from 22 patients with house dust mite allergy and 18 healthy controls, the number of SA colony forming units per ml were assessed and related to nasal symptom scores, the concentrations of three inflammatory cell activation markers, nasal total IgE and 17 cytokines in nasal secretions. SA was found in 15/22 allergic patients and 4/18 controls (P < 0.01). Comparing allergic SA carriers with allergic noncarriers, nasal symptom scores tended to be higher (P < 0.1), and the cell activation markers ECP (10(2.23+/-0.33)vs 10(1.45+/-0.50) ng/ml; P < 0.05) and elastase (10(2.70+/-0.21)vs 10(2.12+/-0.34) ng/ml; P < 0.01), and nasal total IgE-levels (10(1.66+/-0.38)vs 10(1.2+/-0.28) kU/ml; P < 0.05) were significantly higher in allergic SA carriers. Nasal SA carriers had a higher nasal IL-13/IFN-gamma ratio (P < 0.01), and this was correlated with higher nasal total IgE in allergic patients (r = 0.6, P < 0.05). Nasal SA carriage is frequent in patients with persistent allergic rhinitis. The data of this study suggest that they are not only secondary bystanders, but actively modulate the disease by promoting local IgE production.

Molecular Evidence that Nasal Carriage of Staphylococcus aureus Plays a Role in Respiratory Tract Infections of Critically Ill Patients

The relationship between nasal Staphylococcus aureus carriage and lower respiratory tract infections was studied in 16 critically ill patients. S. aureus strains from nasal and bronchial samples were characterized by pulsed-field gel electrophoresis. In all but one case, nasal and bronchial strains were genetically identical in the same patients.

Research Foundation Award for the Best International Abstract, Blue Ribbon Abstract Award: The nasal carriage of methicillin-resistant Staphylococcus aureus in children with allergy

BACKGROUND: Staphylococcus aureus (SA) enterotoxins have been suggested to have an impact on specific local IgE production in nasal polyps in patients with allergy. Hypothetically high level of the local IgE during long period maybe associated with methicillin-resistant Staphylococcus aureus (MRSA) formation in the upper respiratory tract in this enlarging group of children with allergy. The aim of the present investigation was to detect the amount of MRSA carriers among children with allergy: nasal polyposis (NP) and allergic rhinitis (AR). METHODS: Nasopharyngeal swabs for SA and MRSA and nasal tissue samples were taken from 1020 children (ages 2-3, 4-7, 8-12) with NP (456 persons) and AR (564 persons) and 980 healthy children (ages 2-12) enrolled for long-term study from 1999 through 2004. Patient's age, gender, diagnosis of allergy, therapy, IgE levels, and use of antibiotics was recorded. Antibiotic resistance of the strains was determined with the disc diffusion method. Nasal tissue samples were analyzed for total and specific IgE to SA. Nonlineal diagnosis system (NLS) method was used to support analysis and demonstration. RESULTS: The rates of nasal carriage of SA were found to be 15% (147/980) in the control group and 62% (632/1020) in patients with NP and AR. MRSA was found in 2% of control and in 29% of patients with NP and AR in 1999, 3% and 32% in 2000, 2% and 37% in 2001, 1% and 40% in 2002, 1% and 52% in 2003, and 1% and 66% patients in 2004. B1 MRSA strain was predominant. Children ages 4-7 years (p = 0.02), glucocorticoid use in NP (p = 0.02), rate of hospitalization (p = 0.005), and specific local IgE level (p = 0.001) were significantly associated with MRSA colonization. Results were confirmed by NLS in 79% of samples. CONCLUSION: The nasal carriage of MRSA in patients with nasal polyposis is high, undetectable, and growing. It is possible that allergy maybe the cause of nasal carriage of MRSA. Children with NP and AR are an unidentified and less well studied group at high risk for spreading MRSA in children's hospitals, day-care centers, and schools. NLS opens up possibilities for screening for MRSA carriers.

Risk Factor Analysis for Long-Term Tunneled Dialysis Catheter-Related Bacteremias

Infection, mainly related to vascular access, is one of the main causes of morbidity and a preventable cause of death in hemodialysis patients. From January 1994 to April 1998 we conducted a prospective study to assess the incidence and risk factors of catheter-related bacteremia. One hundred and twenty-nine tunneled dual-lumen hemodialysis catheters were inserted percutaneously into the internal jugular vein in 89 patients. Bacteremia (n = 56) occurred at least once with 37 (29%) of the catheters (an incidence of 1.1/1,000 catheter-days); local infection (n = 45, 1/1,000 catheter-days) was associated with bacteremia in 18 cases. Death in 1 case was directly related to Staphylococcus aureus (SA) septic shock, and septicemia contributed to deaths in 2 additional cases. Catheters were removed in 48% of the bacteremic episodes. Treatment comprised intravenous double antimicrobial therapy for 15–20 days. Bacteriological data of bacteremia showed 55% involvement of SA. Nasal carriage of SA was observed in 35% of the patients with catheters. Bacteremic catheters were more frequently observed in patients with diabetes mellitus (p = 0.03), peripheral atherosclerosis (p = 0.001), a previous history of bacteremia (p = 0.05), nasal carriage of SA (p = 0.0001), longer catheter survival time (p = 0.001), higher total intravenous iron dose (p = 0.001), more frequent urokinase catheter infusion (p < 0.01), and local infection (p < 0.001) compared with non-bacteremic catheters. Monovariate survival analysis showed that significant initial risk factors for bacteremia were nasal carriage of SA (p = 0.00001), previous bacteremia (p = 0.0001), peripheral atherosclerosis (p = 0.005), and diabetes (p = 0.04). This study confirms the relatively high incidence of bacteremia with tunneled double-lumen silicone catheters and its potential complications. Possible preventive actions are discussed according to the risk factors.