Carriage of Staphylococcus aureus and of gram-negative bacilli resistant to third-generation cephalosporins in cirrhotic patients: a prospective assessment of hospital-acquired infections.

OBJECTIVE: To study the relation between Staphylococcus aureus nasal and stool colonization, stool carriage of gram-negative bacilli resistant to third-generation cephalosporins (CephR), and subsequent infections during hospitalization. DESIGN: Prospective study. PATIENTS: 551 cirrhotic patients with 589 consecutive hospital stays. All patients were screened within 48 hours of admission; 589 nasal swabs, 417 stool specimens, and 589 urine samples were analyzed. RESULTS: Carriage rates were 18.8% for methicillin-sensitive S aureus (MSSA), 16.3% for methicillin-resistant S aureus (MRSA), and 13.7% for CephR. We observed 87 episodes of spontaneous bacterial peritonitis, 63 cases of bacteremia, and 167 urinary tract infections occurred. Only 1 case of bacteremia and 4 urinary tract infections due to CephR occurred in patients carrying the same organism in their stools. The risk of MRSA ascitic fluid infections, bacteremia, and urinary tract infections was 3.1% versus 1% (not significant), 8.3% versus 0.8% (P<.001), and 11.4% versus 0.6% (P<.001) in carriers and noncarriers, respectively. Pulsed-field gel electrophoresis (PFGE) of isolates from 16 patients infected by MSSA (3 cases) and MRSA (13 cases) demonstrated that the colonizing strains matched the invasive strains in the 3 MSSA cases and in 8 of 13 MRSA cases. CONCLUSION: Carriage of CephR strains is not associated with subsequent infection by these organisms in hospitalized cirrhotic patients. In contrast, MRSA carriage was an important risk factor for MRSA bacteremia and urinary tract infection.     

Sustained low prevalence of meticillin-resistant Staphylococcus aureus upon admission to hospital in The Netherlands

The prevalence of meticillin-resistant Staphylococcus aureus (MRSA) carriage at hospital admission in The Netherlands was 0.03% in 1999–2000. The aim of the present study was to assess whether the prevalence of MRSA carriage in The Netherlands has changed over the last few years. In five Dutch hospitals, 6496 unique patients were screened for nasal S. aureus carriage at hospital admission by microbiological culture between 1 October 2005 and 7 June 2007. In total, 2036 of 6496 (31.3%) patients carried S. aureus in their nose, and seven of 6496 (0.11%) patients were nasal carriers of MRSA. Compared with 1999–2000, the prevalence of MRSA carriage in the Dutch population at hospital admission has increased more than three fold; however, this increase was not significant (P = 0.06, Fisher’s exact test). This prevalence is still among the lowest in the world, probably as a result of the stringent Dutch infection control policy, and the restrictive use of antibiotics in The Netherlands.     

Staphylococcus aureus native arthritis over 10 years

ObjectivesSeptic arthritis is associated with significant case fatality and morbidity. Staphylococcus aureus is the most common cause of arthritis. We aimed to analyze the microbiological features of S. aureus causing native arthritis and to investigate their influence on the clinical outcome of the infection.Patients and methodsWe conducted a retrospective study including all episodes of S. aureus native arthritis between 2005–2015. Phenotypic (antimicrobial susceptibility, β-hemolysis, agr functionality, biofilm formation) and genotypic characteristics (pulsed-field gel electrophoresis, DNA microarrays) were investigated. The primary endpoint was microbiological failure of treatment, including infection relapse, persistence, or attributable death.ResultsTwenty-nine patients were included (65.5% of men, mean age: 59): seven (24.1%) patients presenting with methicillin-resistant S. aureus (MRSA) native arthritis and 19 with methicillin-susceptible S. aureus (MSSA) native arthritis. Treatment failure occurred in seven (26.9%) patients (4/7 patients [57.1%] among MRSA infections vs. 3/19 [15.8%] among MSSA infections). The persistence rate was similar in MRSA and MSSA infections (1/7 vs. 3/19). However, the case fatality was significantly higher in patients with MRSA infection (3/7 vs. 0/19). The most frequent clonal complex (CC) was CC5 (38.1%). MSSA showed higher genetic variability (nine CCs) versus MRSA (3 CCs).ConclusionsBeyond methicillin resistance, we did not find phenotypic or genotypic factors associated with the poor outcome of S. aureus native arthritis. CC5 was the major CC, showing the higher genetic variability of MSSA versus MRSA.     

Random meticillin-resistant Staphylococcus aureus carrier surveillance at a district hospital and the impact of interventions to reduce endemic carriage

Colonisation with meticillin-resistant Staphylococcus aureus (MRSA) has previously been described as a risk factor for subsequent infection. MRSA colonisation reached endemic proportions in most healthcare institutions in the UK during the 1990s. Bacteraemia due to MRSA is associated with increased mortality and morbidity compared with meticillin-susceptible S. aureus and national targets have been set for reduction. We present our findings of regular random colonisation surveillance and systematic decolonisation of MRSA carriers over a five-year period with the aim of reducing the pool of carriers and number of MRSA bacteraemia cases. Interventions to reduce the rate of colonisation included assurance of decolonisation and follow up, targeting wards with the highest carriage rates using enhanced screening and education, and screening all admissions aged >65 years. There was a statistically significant reduction in the proportion of patients colonised from 14.6% to 7.0% (P < 0.001) and the total number of bacteraemia cases from 42 to 22 (P = 0.012) in the initial 24 months of surveillance compared to the most recent 24 months. Regular surveillance of MRSA carriage is useful for monitoring the effects of control measures on MRSA carriage among inpatients. Interventions to reduce carriage are able to reduce the pool of MRSA carriers, thereby reducing cases of bacteraemia.     

Decolonization of Staphylococcus aureus carriage

Staphylococcus aureus nasal colonization is a well-known independent risk factor for infection caused by this bacterium. Screening and decolonization of carriers have been proven effective in reducing S. aureus infections in some populations. However, a gap remains between what has been proven effective and what is currently done. We aimed to summarize recommendations and current knowledge of S. aureus decolonization to answer the following questions: Why? For whom? How? When? And what are the perspectives?     

A clinical trial of mupirocin in the eradication of methicillin-resistant Staphylococcus aureus nasal carriage in a digestive disease unit

We assessed the incidence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) on admission, the rate of acquisition during the hospital stay and the relationship with subsequent infection in a digestive disease unit. The efficacy of a program of nasal carriage eradication with mupirocin was evaluated simultaneously. Over one year 484 patients were studied prospectively on admission for nasal and stool carriage of MRSA, then every week for nasal carriage. Nearly 70% (68.8%) of patients had chronic liver diseases. Nasal carriers were assigned to a five-day course of intranasal mupirocin ointment. One hundred and seventeen (24.2%) patients were MRSA positive, 57 (11.8%) of which were carriers on admission and 60 (12.4%) acquired carriage. Of these, 86 were treated with mupirocin with a success rate of 98.8% and 25.9% of them recolonized. Fourteen patients were retreated, to allow eradication in 71.4% of cases. Seventy percent of these became carriers again. One high-level mupirocin-resistant strain was isolated before treatment and seven during or after treatment. Hospital stay and stool carriage were independently associated with reacquisition (P=0.0105 and P=0.0462, respectively). Molecular analysis showed identity between the strains isolated from infection samples and from nasal swabs during the same week. For every patient who became recolonized, nasal strains isolated before and after eradication were the same in 70% of cases. Mortality during hospital stay was independently associated with age (P=0.0081), MRSA nasal carriage (P=0.02631), MRSA infection (P<0.0001) and liver disease (P=0.0017). This study did not show a change in the prevalence rate of infection in the unit during treatment with mupirocin. This treatment should only be attempted once due to the risk of emergence of high-level resistant strains.     

Methicillin-susceptible, doxycycline-resistant Staphylococcus aureus, Côte d'Ivoire

We report 2 outbreaks of Panton-Valentine leukocidin–positive, doxycycline-resistant, methicillin-susceptible Staphylococcus aureus infections in French soldiers operating in Côte d’Ivoire. In a transssectional survey, nasal carriage of this strain was found in 2.9% of 273 soldiers about to be sent to Côte d’Ivoire and was associated with prior malaria prophylaxis with doxycycline.     

The evolution of Staphylococcus aureus

A broad variety of infections, ranging from minor infections of the skin to post-operative wound infections can be caused by Staphylococcus aureus. The adaptive power of S. aureus to antibiotics leaded, in the early 1960s, to the emergence of methicillin-resistant S. aureus (MRSA). The cause of resistance to methicillin and all other β-lactam antibiotics is the mecA gene, which is situated on a mobile genetic element, the staphylococcal cassette chromosome mec (SCCmec). Seven major variants of SCCmec, type I to VII, are distinguished. The most important techniques used to investigate the molecular epidemiology of S. aureus are pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), S. aureus protein A (spa) typing and SCCmec typing (only for MRSA). These techniques have been used to study the evolution of the MRSA clones that have emerged since the early 1960s, and to study their subsequent worldwide dissemination. The early MRSA clones were hospital-associated (HA-MRSA). However, from the late 1990s, community-associated MRSA (CA-MRSA) clones emerged worldwide. CA-MRSA harbors SCCmec type IV, V or VII, the majority belong to other S. aureus lineages compared to HA-MRSA, and CA-MRSA is often associated with the presence of the toxin Panton-Valentine leukocidin (PVL). However, during recent years, the distinction between HA-MRSA and CA-MRSA has started to disappear, and CA-MRSA is now endemic in many US hospitals. MRSA probably originated trough the transfer of SCCmec into a limited number of methicillin-sensitive S. aureus (MSSA) lineages. This review describes the latest observations about the structure of SCCmec, the techniques used to study the molecular epidemiology and evolution of S. aureus as well as some challenges that researchers face in the future.     

Community-Associated Methicillin-Resistant Staphylococcus aureus, Iowa, USA

We performed antimicrobial drug susceptibility testing and molecular typing on invasive methicillin-resistant Staphylococcus aureus (MRSA) isolates (n = 1,666) submitted to the University of Iowa Hygienic Laboratory during 1999–2006 as part of a statewide surveillance system. All USA300 and USA400 isolates were resistant to <3 non–β-lactam antimicrobial drug classes. The proportion of MRSA isolates from invasive infections that were either USA300 or USA400 increased significantly from 1999–2005 through 2006 (p<0.0001). During 2006, the incidence of invasive community-associated (CA)–MRSA infections was highest in the summer (p = 0.0004). Age <69 years was associated with an increased risk for invasive CA-MRSA infection (odds ratio [OR] 5.1, 95% confidence interval [CI] 2.06–12.64), and hospital exposure was associated with decreased risk (OR 0.07, 95% CI 0.01–0.51).     

Staphylococcus aureus carriage and infections among patients in four haemo- and peritoneal-dialysis centres in Denmark

A three-month prospective surveillance study was undertaken in four dialysis centres to establish the prevalence of Staphylococcus aureus carriage in a Danish population of patients on haemodialysis (HD) or on continuous ambulatory peritoneal dialysis (CAPD). General data such as sex, age, diagnosis, number of months in dialysis, hospital and ward were registered on a precoded form. Standardized nose and four skin swabs (axillae, groins, perineum) were performed on the first day of the survey. After one and two months, nose swabs were collected. Infections were registered and cultures were sent for phage-typing together with the S. aureus strains isolated from the swabs; 59·5% of HD patients and 51·2% of CAPD patients carried S. aureus. Permanent carriage was most frequent (P < 0·00009), primarily in the nose (44·0 and 34·9%, respectively in HD and CAPD). Skin carriage alone was rare (2·4 and 4·7%). Approximately one third (36·6 and 40·7%) of infections were caused by S. aureus. Although diabetics were not significantly more frequent carriers (60·5%) than non-diabetics (55·0%), the incidence of infection was much higher (26·3% vs. 10·3%, P = 0·004). In CAPD, peritonitis and tunnel/exit-site infections pre-dominated (81·4%), often caused by S. aureus (34·8%). More than two thirds of the infections in HD patients were related to intravascular catheterization. The most serious infection was septicaemia, in all cases due to S. aureus. S. aureus infections occurred significantly more frequently among carriers (P = 0·005), and more than half the patients were infected by the same or possibly the same strain as they carried in the nose or on skin. Different regimens for the elimination of S. aureus carriage in dialysis patients are discussed. A policy for risk assessment of patients should be developed, and the elimination of S. aureus carriage before dialysis should be encouraged. Controlled trials comparing the cost-effectiveness of recommended regimens to eliminate carriage in HD/CAPD patients are needed. Nose swabs are reliable indicators of carriage in dialysis patients.     

A bundle of care to reduce colorectal surgical infections: an Australian experience

Staphylococcus aureus carriage increases the risk of infection. Demographic and microbiological data from adult patients with nasal S. aureus carriage were analysed in order to define effect modifiers of this association. Predictors for growth of S. aureus from clinical cultures were identified in a case-control study using bivariate and multi-variate logistic regression analysis. Between 1 January 2005 and 1 April 2009, 645 patients with nasal S. aureus colonization and documented follow-up of ≥90 days were identified; 159 (25%) patients were found to carry meticillin-resistant S.?aureus (MRSA). The median age of patients was 58 years, and 421 (65%) were male. During the subsequent 90 days, one or more clinical cultures were positive for S. aureus in 131 patients (20%). Multi-variate analysis identified a prior history of any S. aureus positive culture [adjusted odds ratio (aOR) 2.4, 95% confidence interval (CI) 1.5-3.8; P=0.0005) as an independent predictor of subsequent S. aureus infection. MRSA colonization was a predictor of infection in patients aged >40 years (aOR 2.5, 95% CI 1.4-4.1; P=0.0004), and even more so in patients aged ≤40 years (aOR 12.4, 95% CI 3.0-51; P=0.0005). Age >40 years was an additional independent risk?factor for meticillin-susceptible S. aureus carriers (aOR 3.0, 95% CI 1.2-7.8; P=0.02) but not for MRSA carriers. Preferential screening of patients at high risk for MRSA carriage and subsequent infection, as well as the absence of a universal policy for the use of decolonization regimens, may partly explain the relatively high risk of S. aureus infection in the patient population. MRSA carriers and older patients with recurrent S. aureus positive cultures may gain the greatest benefit from routine decolonization measures.     

Methicillin-Resistant and -Susceptible Staphylococcus aureus Infections in Dogs

Methicillin-resistant Staphylococcus aureus (MRSA) has become a pathogen of animals. To compare types of infections, clinical outcomes, and risk factors associated with MRSA in dogs with those associated with methicillin-susceptible Staphylococcus aureus (MSSA) infections, we conducted a case–control study at 3 veterinary referral hospitals in the United States and Canada during 2001–2007. Risk factors analyzed were signalment, medical and surgical history, and infection site. Among 40 dogs with MRSA and 80 with MSSA infections, highest prevalence of both infections was found in skin and ears. Although most (92.3%) dogs with MRSA infections were discharged from the hospital, we found that significant risk factors for MRSA infection were receipt of antimicrobial drugs (odds ratio [OR] 3.84, p = 0.02), β-lactams (OR 3.58, p = 0.04), or fluoroquinolones (OR 5.34, p = 0.01), and intravenous catheterization (OR 3.72, p = 0.02). Prudent use of antimicrobial drugs in veterinary hospitals is advised.     

Outbreak of Panton-Valentine Leukocidin–Associated Methicillin-Susceptible Staphylococcus aureus Infection in a Rugby Team,France, 2010–2011

Staphylococcus aureus strains that produce Panton-Valentine leukocidin are known to cause community infections. We describe an outbreak of skin abscesses caused by Panton-Valentine leukocidin–producing methicillin-susceptible S. aureus (clonal complex 121) in a professional rugby team in France during July 2010–February 2011. Eight team members were carriers; 7 had skin abscesses.     

Panton-Valentine leukocidin producing Staphylococcus aureus nasal carriage,in North-Lebanon

Objectives

We investigated the prevalence and the risk factors of nasal carriage of Staphylococcus aureus carrying Panton-Valentine leukocidin genes [Sa PVL(+)] in pupils.

Study population and methods

Two hundred and fifty-seven pupils were screened by nasal swabbing. The detection of 16S rRNA, mecA and luk-PV genes was performed by PCR and the risk factors were assessed with the statistical analysis of a questionnaire.

Results

Thirty-one percent of pupils were colonized, with 16.4% of isolates carrying the luk-PV gene and 8.8% the mecA gene. Children aged 7 years or more and living in a boarding school were the factors promoting nasal carriage 60% of children who presented with an abscess in the previous year were carriers of luk-PV gene Sa.

Conclusion

The study revealed a high prevalence of luk-PV gene among methicillin-susceptible strains and a statistically significant correlation between the presence of this gene and presenting with an abscess.     

Unexpected categories at risk of S. aureus nasal carriage among hospital workers

ObjectivesThirty percent of the general population are Staphylococcus aureus nasal carriers. It has been shown that this increases with repeated contact with patients, but it is not known whether all categories of healthcare workers are at equal risk of carriage. We aimed to explore S. aureus nasal carriage among healthcare professionals.MethodsProspective study conducted in two French university hospitals in 2014 and 2016. Volunteers were screened for S. aureus nasal carriage. Profession and hygiene habits were collected. Based on the results of this initial study, a second study focused on semi-skilled workers and biomedical equipment technicians (BETs) only; participants were given education on the basic rules of hygiene, then re-screened three months later.ResultsIn the initial study, 38.8% of the 436 participants were detected as nasal carriers. There was a significant difference in nasal carriage according to professional category (p < 0.0001); the lowest was found among administrative agents (17.3%), followed by healthcare providers (37.4%), laboratory technicians (37.6%). The greatest proportion was found among semi-skilled workers and BETs (52.9%). Spa-typing ruled out the hypothesis of a single clone dissemination among colleagues. After the three-month hygiene awareness campaign, all re-screened individuals remained positive, and with their respective initial strain.ConclusionsTo the best of our knowledge we report here for the first time that semi-skilled workers and BETs are specifically more at risk of S. aureus nasal colonisation. This striking finding urges hospital hygiene departments to evaluate this specific professional category and implement strategies to improve hygiene awareness.     

Isolation and antimicrobial susceptibility pattern of Staphylococcus aureus in patients with surgical site infection at Debre Markos Referral Hospital,Amhara Region,Ethiopia

Background

Staphylococcus aureus, especially Methicillin Resistant Staphylococcus Aureus (MRSA) is a major health problem recognized as the most important nosocomial pathogen, often causing postoperative wound infections. Antibiotic resistance by MRSA has grown to be common, and resistance to almost all antibiotics has been found among these strains. The aim of this study was to determine the prevalence, antimicrobial susceptibility patterns and associated risk factors of S. aureus in patients with surgical site infections in an Ethiopian hospital.

Methods

A cross-sectional study was conducted from December 1, 2011 to March 30, 2012 among patients with surgical site infections at Debre Markos Referral Hospital, Debre Markos, Ethiopia. All wound swabs obtained from patients with surgical site infections during the study period were cultured on mannitol salt agar media which is selective for S. aureus. Isolated strains of S. aureus were tested for antibiotic susceptibility patterns using standard disc diffusion technique, and interpretation of resistance was done based on Clinical and Laboratory Standard Institute criteria. Univariate and multivariable analyses were used to assess the risk factors.

Results

Of the 184 surgical patients who had developed surgical site infection, S. aureus was isolated from 73 (39.7%) cases. Out of the 73 isolates of S. aureus, 36 (49.7%) were MRSA. Among the study participants, prevalence of MRSA was found to be 19.6%. The clinical isolates showed >80% level of resistance to ampicillin, amoxicillin, penicillin G, erythromycin, gentamicin and cotrimoxazole whereas <50% level of resistance was observed against clindamycin, oxacillin, tetracycline and vancomycin. MRSA strains showed resistance ranging from 5.6% (vancomycin) to 100% (cotrimoxazole). Of the following risk factors: sex, age, pus consistency, duration of operation, type of surgery, ward and hospital stay, laparotomy type of surgery was identified as a risk factor for infection by S. aureus.

Conclusion

The prevalence of S. aureus and/or MRSA infection in surgical and gynaecology & obstetrics wards of Debre Markos Referral Hospital was found to be high. The majority of isolates were highly resistant to major antimicrobial agents.     

The relationship between hand hygiene practices and nasal Staphylococcus aureus carriage in healthcare workers

Background:The nasal carriage rate of Staphylococcus aureus in healthcare workers (HCWs) is higher than the general population. Their hands serve as vectors for transmitting S.aureus colonized in the nose to patients.Objectives:To determine the rate of nasal S.aureus carriage and methicillin resistance in HCWs and to evaluate the relationship between carriage and personal risk factors and hand hygiene behaviors.Methods:The questionnaire included questions about sociodemographic characteristics, occupational and personal risk factors for S.aureus carriage, the “Hand Hygiene Belief Scale (HHBS),” and “Hand Hygiene Practices Inventory (HHPI)”. Nasal culture was taken from all participants. Presence of S.aureus, methicillin and mupirocin resistance were investigated in samples.Results:The study was carried out with 269 HCWs. The prevalence of S.aureus carriage was 20.1% (n:54). Among 54 S.aureus carriers, only one person had MRSA (0.37%). All S.aureus isolates were susceptible to mupirocin. S.aureus carriage was found to be significantly lower in the smoker group (p:0.015) and in the personnel wearing gloves during the procedures of each patient (p:0.002). S.aureus culture positivity was found to decrease significantly with increasing handwashing frequency (p:0.003). The mean HHPI score was higher in women (p:0.001). The mean HHPI score was lower in the group with nasal carriers than in non-carriers (p:0.176).Conclusion:The knowledge of hand hygiene practices, high frequency of handwashing, and wearing different gloves during the procedure of each patient decrease S.aureus nasal carriage in HCWs. In addition mupirocin is still effective in nasal S.aureus carriers.Key words: Staphylococcus aureus, nasal carriage, hand hygiene practices     

Tea and coffee consumption and MRSA nasal carriage

PURPOSE Hot tea and coffee have been found to have antimicrobial properties. The purpose of this study was to determine whether the consumption of tea, coffee, or both is associated with less frequent nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA).METHODS We performed a secondary analysis of data from the 2003–2004 National Health and Nutrition Examination Survey to investigate the relationship between the consumption of coffee, hot tea, cold tea, and soft drinks, and MRSA nasal carriage among the noninstitutionalized population of the United States.RESULTS An estimated 2.5 million persons (1.4% of the population) were MRSA nasal carriers. In an adjusted logistic regression analysis controlling for age, race, sex, poverty-income ratio, current health status, hospitalization in the past 12 months, and use of antibiotics in the past month, individuals who reported consuming hot tea were one-half as likely to have MRSA nasal carriage relative to individuals who drank no hot tea (odds ratio = 0.47; 95% confidence interval, 0.31–0.71). Similarly, individuals who reported consuming coffee had about a one-half reduction in the risk of MRSA nasal carriage relative to individuals who drank no coffee (odds ratio = 0.47; 95% confidence interval, 0.24–0.93).CONCLUSIONS Consumption of hot tea or coffee is associated with a lower likelihood of MRSA nasal carriage. Our findings raise the possibility of a promising new method to decrease MRSA nasal carriage that is safe, inexpensive, and easily accessible.     

Control of a cluster of community-associated, methicillin-resistant Staphylococcus aureus in neonatology

To control an outbreak of community-associated MRSA (CA-MRSA) in a neonatology unit, an investigation was conducted that involved screening neonates and parents, molecular analysis of MRSA isolates and long-term follow-up of cases. During a two-month period in the summer of 2000, Panton-Valentine leukocidin (PVL)-producing CA-MRSA (strain ST5-MRSA-IV) was detected in five neonates. The mother of the index caseshowed signs of mastitis and wound infection and consequently tested positive for CA-MRSA. A small cluster of endemic, PVL-negative MRSA strains (ST228-MRSA-I) occurred in parallel. Enhanced hygiene measures, barrier precautions, topical decolonization of carriers, and cohorting of new admissions terminated the outbreak. Four months after the outbreak, the mother of another neonate developed furunculosis with the epidemic CA-MRSA strain. One infant had persistent CA-MRSA carriage resulting in skin infection in a sibling four years after the outbreak. In conclusion, an epidemic CA-MRSA strain was introduced by the mother of the index case. This spread among neonates and was subsequently transmitted to another mother and a sibling. This is the first report of a successfully controlled neonatology outbreak of genetically distinct PVL-producing CA-MRSA in Europe.     

Methicillin-Susceptible,Vancomycin-Resistant Staphylococcus aureus,Brazil

We report characterization of a methicillin-susceptible, vancomycin-resistant bloodstream isolate of Staphylococcus aureus recovered from a patient in Brazil. Emergence of vancomycin resistance in methicillin-susceptible S. aureus would indicate that this resistance trait might be poised to disseminate more rapidly among S. aureus and represents a major public health threat.