Staphylococcus aureus bacteremia and endocarditis: the Grady Memorial Hospital experience with methicillin-sensitive S aureus and methicillin-resistant S aureus bacteremia

Background

Staphylococcus aureus has become the leading cause of endocarditis in most published series, and nosocomial acquisition is becoming more frequent. Previous studies involved community acquired methicillin-sensitive S aureus (MSSA), but recently, methicillin-resistant S aureus(MRSA) infection has increased. This may reflect the growing presence of this microorganism in clinical practice. Few data exist comparing the relative rates of endocarditis with MSSA and MRSA bacteremia. The purpose of this study was to compare these rates in a bacteremic population referred for diagnostic echocardiography.

Methods

Since July 1999, the demographic and clinical information of 104 consecutive patients with at least 2 blood cultures with positive results for S aureus who were referred for echocardiography to be evaluated for endocarditis at Grady Memorial Hospital (Atlanta, Ga) have been entered into a database. This database has further been restricted to patients who have undergone either a transesophageal echocardiogram or a transthoracic echocardiogram.

Results

Of the 104 patients with S aureus bacteremia, 53 had an infection of MSSA and 51 had an infection of MRSA. There were 33 patients (31.7%) with echocardiographically confirmed endocarditis, 23 patients (43.4%) in the MSSA group versus10 patients (19.6%) in the MRSA group (P <.009). Community-acquired MSSA bacteremia was the cause of most of the community-acquired S aureus endocarditis (20 patients [87%] vs 3 patients [30%], P = .004), and the nosocomial-acquired MRSA bacteremia was the cause of most of the nosocomial-acquired S aureus endocarditis (3 patients [13%] vs 7 patients [70%], P = .0001).

Conclusion

Our study confirms that S aureus bacteremia is associated with high rates of endocarditis. MSSA bacteremia is associated with higher rates of endocarditis than MRSA. Community MSSA is the cause of most of the community endocarditis, whereas nosocomial MRSA is the cause of most of the MRSA endocarditis. Patients with S aureus bacteremia should be aggressively evaluated for endocarditis.     

Aumento significativo de la colonización por Staphylococcus aureus entre los estudiantes de medicina durante la realización de las prácticas en el hospital

Introduction

Staphylococcus aureus is a pathogen of major concern. The emergence of methicillin-resistant S. aureus (MRSA) has increasingly complicated the therapeutic approach of hospital-acquired infections. Surveillance of MRSA and control measures must be implemented in different healthcare settings, including screening programs for carriers. Our first aim was to determine the prevalence of methicillin-susceptible S. aureus (MSSA) and MRSA nasal carriage in medical students from the Clínico San Carlos Hospital (Madrid). As the MRSA carrier rate in healthcare workers is higher than in the general population, we hypothesised that carrier rate could be increased during their clinical practice in their last three years.

Methods

We performed an epidemiologic al study of the prevalence of S. aureus colonisation among a group of medical students, who were sampled in 2008 in their third-year, and in 2012 when this class was in its sixth year.

Results

We have found a significant increase in MSSA carriage, from 27% to 46%. There were no MRSA colonisations in the third-year, but one was found in the sixth-year group. The large majority of strains (89%) of strains were resistant to penicillin, and 27% to erythromycin and clindamycin. As 19 coagulase-negative Staphylococcus MR were also identified, a horizontal transfer of genes, such as mecA gene to S. aureus, could have occurred.

Conclusions

Medical students are both, at risk for acquiring, and a potential source of nosocomial pathogens, mainly MSSA. Therefore, they should take special care for hygienic precautions, such as frequent and proper hand washing, while working in the hospital.     

Fifteen-year study of the changing epidemiology of methicillin-resistant Staphylococcus aureus

Purpose

The study’s purpose was to elucidate the evolutionary, microbiologic, and clinical characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infections.

Methods

MRSA cases from military medical facilities in San Diego, from 1990 to 2004, were evaluated and categorized as community-acquired or nosocomial. Sequence type, staphylococcal chromosomal cassette gene type, and Panton-Valentine leukocidin gene status were determined for a subset of isolates.

Results

Over the 15-year period, 1888 cases of MRSA were identified; 65% were community acquired. The incidence (155 infections/100 000 person-year in 2004) and household-associated cases rapidly increased since 2002. Among persons with community-acquired MRSA, 16% were hospitalized and only 17% were initially given an effective antibiotic. Community-acquired MRSA cases compared with nosocomial MRSA cases were more often soft-tissue and less often urinary, lung, or bloodstream infections (P < .001). Patients with community-acquired MRSA were younger (22 vs 64 years, P < .001) and less likely to have concurrent medical conditions (9% vs 98%, P < .001). Clindamycin resistance increased among community-acquired MRSA isolates during 2003 and 2004 compared with previous years (79% vs 13%, P < .001). Genetically, nosocomial MRSA isolates were significantly different than those acquired in the community. Although community-acquired MRSA isolates were initially diverse by 2004, one strain (staphylococcal chromosomal cassette type IV, sequence type 8, Panton-Valentine leukocidin gene positive) became the predominant isolate.

Conclusions

Community-acquired and intrafamilial MRSA infections have increased rapidly since 2002. Our 15 years of surveillance revealed the emergence of distinct community-acquired MRSA strains that were genetically unrelated to nosocomial MRSA isolates from the same community.     

Clinical and bacteriological survey of diabetic foot infections in Lisbon

Aims

An epidemiological survey of diabetic foot infections (DFIs) in Lisbon, stratifying the bacterial profile based on patient demographical data, diabetic foot characteristics (PEDIS classification), ulcer duration and antibiotic therapy.

Methods

A transversal observational multicenter study, with clinical data collection using a structured questionnaire and microbiological products (aspirates, biopsies or swabs collected using the Levine method) of clinically infected foot ulcers of patients with diabetes mellitus (DM).

Results

Forty-nine hospitalized and ambulatory patients were enrolled in this study, and 147 microbial isolates were cultured. Staphylococcus was the main genus identified, and methicillin-resistant Staphylococcus aureus (MRSA) was present in 24.5% of total cases. In the clinical samples collected from patients undergoing antibiotic therapy, 93% of the antibiotic regimens were considered inadequate based on the antibiotic susceptibility test results. The average duration of an ulcer with any isolated multi-drug resistant (MDR) organism was 29 days, and previous treatment with fluoroquinolones was statistically associated with multi-drug resistance.

Conclusions

Staphylococcus aureus was the most common cause of DFIs in our area. Prevalence and precocity of MDR organisms, namely MRSA, were high and were probably related to previous indiscriminate antibiotic use. Clinicians should avoid fluoroquinolones and more frequently consider the use of empirical anti-MRSA therapy.     

Staphylococcus Aureus Bacteremia Among Patients with Health Care-associated Fever

Background

Although Staphylococcus aureus bacteremia is a common, serious infection, accurately identifying febrile patients with this diagnosis at the time of initial evaluation is difficult. The purpose of this investigation was to define clinical characteristics present at the time of the initial recognition of fever that were associated with the presence of any bloodstream infection and, in particular, with S. aureus bacteremia.

Methods

All patients ≥18 years of age with a new episode of health care-associated fever (temperature ≥38°C) and at least one blood culture drawn were eligible for enrollment into this prospective multicenter cohort study. Multivariable analyses were conducted and internally validated scoring systems were developed to categorize the risk of bacteremia.

Results

Of 1015 patients enrolled, 181 patients (17.8%) had clinically significant bacteremia, including 77 patients (7.6%) with S. aureus bacteremia. Clinical characteristics associated with S. aureus bacteremia were the presence of a hemodialysis graft or shunt (odds ratio [OR] 3.22; 95% confidence interval [CI], 1.85-5.61), chills (OR 2.38; 95% CI, 1.43-3.98), and a history of S. aureus infection (OR 2.68; 95% CI, 1.38-5.20). Peripheral vascular catheters were inversely associated with S. aureus bacteremia (OR 0.42; 95% CI, 0.26-0.69). Clinical characteristics associated with any bloodstream infection were central venous access, chills, history of S. aureus infection, and hemodialysis access.

Conclusions

Among patients with health care-associated fever, the presence of easily recognizable clinical characteristics at the time of obtaining the initial blood cultures can help to identify patients at increased risk for any bloodstream infection, in particular for S. aureus bacteremia.     

Methicillin-resistant Staphylococcus aureus colonization among medical residents

BACKGROUND:

Medical residents may be at risk of becoming colonized by methicillin-resistant Staphylococcus aureus (MRSA) during their training. The occupational risk of this specific population is unknown. Furthermore, there are no data regarding MRSA colonization among health care professionals in Quebec.

OBJECTIVE:

To determine the MRSA colonization rate in Laval University (Quebec City, Quebec) medical residents and compare it with the MRSA colonization rate of a control group.

METHODS:

A controlled cross-sectional study of MRSA prevalence among medical residents of Laval University was performed. The control group consisted of Laval University undergraduate medical students without previous clinical rotations in their curriculum. After informed consent was obtained, participants were screened for MRSA with a nasal swab in both anterior nares. They also completed a questionnaire regarding relevant risk factors and demographic data.

RESULTS:

A total of 250 residents of all residency levels from medical and surgical specialties and 247 controls were recruited between February and April 2010. One case of MRSA colonization was detected among the residents and none in the control group (prevalence of 0.4% versus 0.0%; P=1.00).

DISCUSSION:

MRSA nasal carriage was very low among Laval University residents. This may reflect the decreasing rate of health care-associated MRSA in Quebec City. Young age and good health may also explain this low risk. The strict infection control policies for MRSA patients (including cohorting, use of gloves, gown and patient-dedicated equipment) may also contribute to prevent MRSA transmission.

CONCLUSIONS:

Medical residents in Quebec City appeared to be at very low risk of contracting MRSA through professional activities.     

Evaluating the probability of previously unknown carriage of MRSA at hospital admission

Purpose

We determined the prevalence and risk profile of patients with previously unknown carriage of methicillin-resistant Staphylococcus aureus (MRSA) at hospital admission.

Subjects and methods

We conducted a 7-month, prospective case-controlled study in adult inpatients admitted to a university hospital with endemic MRSA. Multivariate conditional logistic regression for data sets matched 1:4 was performed to identify the risk profile of newly identified MRSA carriers.

Results

Overall, 399 of 12 072 screened admissions (prevalence, 3.3%) were found colonized (n = 368, 92%) or infected (n = 31, 8%) with MRSA. In 204 cases (prevalence, 1.7%), MRSA carriage was newly identified. Without screening on admission, 49% (196/399) of MRSA carriers would have been missed. We identified nine independent risk factors for newly identified MRSA carriage at admission (adjusted odds ratio): male sex (1.9); age greater than 75 years (2.0); receipt of fluoroquinolones (2.7), cephalosporins (2.1), and carbapenems (3.2) in the last 6 months; previous hospitalization (1.9) or intravenous therapy (1.7) during the last 12 months; urinary catheter at admission (2.0); and intrahospital transfer (2.4). A risk score (range, 0-13) was calculated by adding points assigned to these variables. On the basis of analysis of 1006 patients included in the case-controlled study, the probability of MRSA carriage was 8% (28/342) in patients with a low score (≤1), 19% (92/482) in patients with an intermediate score (2-4), and 46% (84/182) in patients with a high score (≥5). The risk score had good discrimination (c-statistic, 0.73) and showed excellent calibration (P = .88).

Conclusions

On-admission prevalence of previously unknown MRSA carriers was high. Applying the risk score to newly admitted patients with an intermediate or high probability of MRSA carriage could allow a more effective MRSA control strategy.     

Staphylococcus aureus bacteremia in patients with prosthetic devices: costs and outcomes

Purpose

Although Staphylococcus aureus is a leading cause of nosocomial infection, little is known about the impact of S. aureus bacteremia on patients with prosthetic devices. This investigation sought to define the clinical outcome, health care resource use, and infection-associated costs of S. aureus bacteremia in patients with prostheses.

Subjects and methods

All hospitalized patients with a prosthetic device and S. aureus bacteremia during the 96-month study period were identified prospectively. Clinical data were collected at the time of hospitalization. Data regarding infection-related resource utilization and infection-related costs within 12 weeks of the initial bacteremia were also recorded.

Results

298 patients with ≥1 prosthesis and S. aureus bacteremia were identified (cardiovascular device—122 patients, orthopedic device—73 patients, long-term catheter—71 patients, and other devices—32 patients). Overall, 58% of patients underwent surgery as a consequence of the infection. Infection-related complications occurred in 41% and the overall 12-week mortality was 27%. The mean infection-related cost was $67 439 for patients with hospital-acquired S. aureus bacteremia and $37 868 for community-acquired S. aureus bacteremia (cost difference $29 571; 95% confidence interval, $14 370-$49 826). Rates of device infection, complications, 12-week mortality, and mean cost varied by prosthesis type.

Conclusion

S. aureus bacteremia in patients with prosthetic devices is associated with frequent complications, substantial cost, and significant health care resource utilization.     

Spontaneous pyogenic vertebral osteomyelitis and endocarditis: incidence, risk factors, and outcome

Purpose

The relationship between pyogenic vertebral osteomyelitis and infectious endocarditis is uncertain. This study investigates the incidence and risk factors of infectious endocarditis in patients with pyogenic vertebral osteomyelitis, and the outcome of pyogenic vertebral osteomyelitis with and without associated infectious endocarditis.

Methods

A retrospective record review was conducted of all cases of vertebral osteomyelitis from January 1986 to June 2002, occurring in a tertiary referral hospital. Patients were followed for at least 6 months with careful attention to detection of infectious endocarditis and relapses.

Results

Among 606 patients with infectious endocarditis, 28 (4.6%) had pyogenic vertebral osteomyelitis. Among 91 cases of pyogenic vertebral osteomyelitis, 28 (30.8%) had infectious endocarditis. In 6 patients with no clinical signs of infectious endocarditis, the disease was established by routine echocardiography. Infectious endocarditis was more common in patients with predisposing heart conditions and streptococcal pyogenic vertebral osteomyelitis infection. Overall, pyogenic vertebral osteomyelitis in-hospital mortality was 11% (7.1% with infectious endocarditis). Twelve of 25 patients with infectious endocarditis with uncomplicated pyogenic vertebral osteomyelitis were treated for 4 to 6 weeks (endocarditis protocol), with no pyogenic vertebral osteomyelitis relapses.

Conclusions

When specifically sought, the incidence of infectious endocarditis is high in patients with pyogenic vertebral osteomyelitis. Oral therapy may be an option for uncomplicated pyogenic vertebral osteomyelitis; nevertheless, in gram-positive infections, this approach should only be considered after excluding infectious endocarditis. Favorable outcome with shorter treatment in uncomplicated pyogenic vertebral osteomyelitis associated with infectious endocarditis suggests that prolonged therapy may not be needed in this subgroup except for those infected by difficult to treat microorganisms, such as methicillin-resistant Staphylococcus aureus or Candida spp.     

A Caenorhabditis elegans host model correlates with invasive disease caused by Staphylococcus aureus recovered during an outbreak in neonatal intensive care

BACKGROUND:

Caenorhabditis elegans has previously been used as a host model to determine the virulence of clinical methicillin-resistant Staphylococcus aureus isolates. In the present study, methicillin-susceptible S aureus (MSSA) strains associated with an outbreak in a neonatal intensive care unit (NICU) were investigated using the C elegans model.

METHODS:

Two distinct outbreak clones, MSSA type-C and MSSA type-G, were identified by pulsed-field gel electrophoresis in a MSSA outbreak during a seven-month period in the NICU of the Sunnybrook Health Sciences Centre (Toronto, Ontario). MSSA type-C was associated with severe infection, while type-G was associated with less invasive disease. Four representative type-C isolates, three type-G and three infant-colonized isolates unrelated to the outbreak, were sent to Calgary (Alberta), for the double-blinded virulence tests in the C elegans host model and for further molecular characterization.

RESULTS:

The invasive outbreak strains (type-C) demonstrated highly nematocidal activity, the noninvasive outbreak strains (type-G) an intermediate virulence, and the outbreak-unrelated colonization isolates demonstrated avirulence or low virulence in the C elegans model, with mean killing rates of 93.0%, 61.0% and 14.4% by day 9, respectively, for these three group strains. Different group MSSA strains had their own unique genetic profiles and virulence gene profiles, but all isolates within the same group (type-C or type-G) shared identical genetic characteristics and virulence gene patterns.

CONCLUSIONS:

The present blinded evaluation demonstrated that the nematocidal activities of MSSA strains correlated well with the clinical manifestation in an MSSA outbreak in the NICU, supporting C elegans as a robust host model to study the pathogenesis of S aureus.     

Clinical and economic burden of bloodstream infections caused by meticillin-resistant and meticillin-susceptible Staphylococcus aureus in Chinese tertiary hospitals from 2010 to 2017: a multicentre,retrospective cohort study

Background

Globally, antimicrobial resistance has become one of the most complex public health challenges. Accurate estimates of health and economic burden of antimicrobial resistance has not been available in China because of the absence of representative empirical data. We therefore aimed to estimate the effect of antimicrobial resistance attributable to Staphylococcus aureus bloodstream infections in Chinese hospitals, and to compare the effect of resistant strains with susceptible strains.

The obesity gene and colorectal cancer risk: a population study in Northern Italy

Background

Representing the second cause of cancer-related death after lung cancer in men and breast cancer in women, colorectal cancer (CRC) is a major health problem in Italy. Obesity is reckoned to favor CRC; however, the underlying mechanisms are unclear. Recently, a single nucleotide polymorphism (SNP) in the fat mass and obesity associated (FTO) gene was found to be significantly associated with obesity.

Aims

To establish whether the FTO SNP rs9939609 may represent a risk factor for CRC and adenoma in the Italian population.

Patients and methods

1,037 subjects were enrolled in the study and divided in 3 groups: CRC (341 pts., M/F = 197/144, mean age = 65.17 ± 11.16 years), colorectal adenoma (385 pts., M/F = 247/138, mean age = 62.49 ± 13.01 years), healthy controls (311 pts., M/F = 150/161, mean age = 57.31 ± 13.84 years). DNA was extracted from whole blood, and stored frozen for rs9939609 genotyping by real-time PCR.

Results

The frequency of the obesity-associated mutated A allele (AA+AT) on the FTO gene was 69.77% among controls, and 71.85% and 65.71% respectively among CRC and polyp patients. Compared to control subjects the AA+AT genotype had no significant effect on the risk for either CRC (OR = 1.106; CI 95% = 0.788-1.550; p = 0.561) or colorectal adenomas (OR = 0.830; CI 95% = 0.602-1.144; p = 0.255). We did not observe any association between the AA genotype and CRC/polyp localization and age at diagnosis. As measured in a patient subset, carriership of the risk alleles did not reflect in a significantly altered BMI.

Conclusion

The obesity-linked FTO variants do not play a significant role in modulating the colorectal cancer risk in the Italian population.     

Methicillin-resistant Staphylococcus aureus colonization among health care workers in a downtown emergency department in Toronto,Ontario

BACKGROUND:

Methicillin-resistant Staphylococcus aureus (MRSA) acquired in the community, otherwise known as community-acquired MRSA, has emerged rapidly in recent years. Colonization with MRSA has been associated with an increased risk of symptomatic and serious infections and, in some settings, health care workers (HCWs) exhibit a higher prevalence of MRSA colonization.

OBJECTIVE:

To determine MRSA colonization in emergency department (ED) HCWs in the setting of a moderate prevalence of MRSA in skin and soft tissue infections.

METHODS:

The present study was conducted at a downtown ED in Toronto, Ontario. ED HCWs completed a brief questionnaire and swabs were taken from one anterior nare, one axilla and any open wounds (if present). Swabs were processed using standard laboratory techniques.

RESULTS:

None of the 89 staff (registered nurses [n=55], physicians [n=15], other [n=19]) were MRSA positive and 25 (28.1%) were colonized with methicillin-susceptible S aureus.

CONCLUSIONS:

Contrary to common belief among HCWs and previous studies documenting MRSA colonization of HCWs, MRSA colonization of this particular Canadian ED HCW cohort was very low and similar to that of the local population.     

Molecular characteristics and virulence gene profiles of Staphylococcus aureus causing bloodstream infection

Background

The rate of methicillin-resistant Staphylococcus aureus (MRSA) among the total of S. aureus isolates decreased to 35.3% in 2017 in China. It is unclear whether the molecular characteristics of S. aureus isolates have changed as the rate decreased.

Fluoroquinolone-resistant Escherichia coli in the long-term care setting

Background

Prior studies have found fluoroquinolone exposure to be a risk factor for infection with fluoroquinolone-resistant gram-negative rods in the acute care setting. However, risk factors may be different in the long-term care setting.

Methods

A case-control study design was used to determine whether fluoroquinolone exposure is a risk factor for fluoroquinolone-resistant Escherichia coli urinary tract infections in a long-term care center. Cases had fluoroquinolone-resistant E. coli urinary tract infections; 4 controls were selected for each case.

Results

Thirty-three case patients were eligible; 132 controls were then selected. In the multivariable analysis, fluoroquinolone-resistant E. coli urinary tract infection was more common with prior fluoroquinolone use (odds ratio 21.8, 95% confidence interval, 3.7-127.1).

Conclusions

Prior fluoroquinolone use is a strong risk factor for fluoroquinolone-resistant E. coli urinary tract infection in the long-term care setting. Further studies are needed to examine the effect of interventions to decrease fluoroquinolone-resistant infections in the long-term care setting, including studying the effect of decreasing fluoroquinolone use.     

Essentials in the management of <Emphasis Type="Italic">S. aureus</Emphasis> bloodstream infection

Aims

Staphylococcus aureus bloodstream infection is one of the most common serious bacterial infections worldwide. It represents a heterogenous clinical entity with a high risk of metastatic complications and a high in-hospital mortality ranging between 20 and 30%. The outcome can be improved by optimised diagnostic and therapeutic management. Thus, our minireview should provide important and often missed pieces of information in the management of S. aureus bloodstream infection.

Methods

We describe the essentials in the management of S. aureus bloodstream infection.

Results

Five essentials were identified: 1) S. aureus bacteremia should always be considered clinically significant. 2) Length of bacteremia and fever is relevant for diagnostic workup, duration of therapy and prognosis. 3) Prompt identification and eradication of portal of entry and infective/metastatic foci are essential. 4) Infective endocarditis should be excluded. 5) Intravenous treatment for at least two weeks up to 4–6 weeks with antistaphylococcal penicillins for MSSA and vancomycin or daptomycin for MRSA bloodstream infection is indicated.

Conclusion

Further efforts should be undertaken to increase the adherence to the essentials in the management of S. aureus bloodstream infection.

     

Colonización nasal por Staphylococcus aureus en estudiantes de medicina: importancia en la transmisión hospitalaria

Background

Staphylococcus aureus is the main pathogen causing nosocomial infections. Health professionals, including medical students, could be a source of transmission. The aims of the study were to determine the rate of nasal carriage of S. aureus susceptible and resistant to methicillin (MRSA) and evaluate the knowledge and adherence that students had about hand hygiene.

Methods

The study included medical students attached to the Hospital Universitario 12 de Octubre (Madrid, Spain). We collected samples from both nasal vestibules, and the antimicrobial susceptibility was determined on all isolates. Data collection was performed using a self-administered questionnaire that included risk factors for colonization, hygiene habits and knowledge of hand hygiene protocols.

Results

Of the 140 students included, 55 (39.3%) were colonized by S. aureus, and 3 (2,1%) by MRSA. The exposure to antibiotics in the last 3 months was lower in colonized students (12.3% vs. 25.9%, P = .03). Self-assessment showed that 56.4% of students almost never washed their hands before to attending to the first patient, and only 38.6% always washed after examining patients. More than a third (35.7%) ignored the hand hygiene protocol, and 38.6% had not received specific formation.

Conclusions

Medical students should be included in hospital infection control programs. Hand hygiene training should be given to students before they begin their practices in the hospital.     

Conservative treatment of staphylococcal prosthetic joint infections in elderly patients

Background

We report the outcome of debridement and prosthesis retention plus long-term levofloxacin/rifampicin treatment of prosthetic joint infections.

Methods

Staphylococcal prosthesis joint infections were defined by positive culture of joint aspirate, intraoperative debridement specimens, or sinus tract discharge in the presence of clinical criteria. Patients received long-term oral levofloxacin 500 mg and rifampicin 600 mg once per day. Sixty patients (age 74.6 ± 8.4 years) were included.

Results

Coagulase-negative staphylococci were significantly more frequently isolated in the knee (78.6%; P = .00001). Of the Staphylococcus aureus isolates, 33.3% were methicillin-resistant. Time from arthroplasty to symptoms onset was higher (P = .03) in coagulase-negative staphylococci infections. Global failure was 35% (higher for the knee) and ranged from 16.6% to 69.2% (P = .0045) in patients with symptoms duration of less than 1 month to more than 6 months. A shorter duration of symptoms (P = .001) and time to diagnosis (P = .01) were found in cured patients versus patients showing failure. Among those with S. aureus infections, a higher failure rate was found with methicillin-resistance.

Conclusions

Efficacy was higher in patients with shorter duration of symptoms, earlier diagnosis, hip infections, and methicillin susceptibility.     

Staphylococcus aureus carriage in older populations in community residential care homes: Prevalence and molecular characterization of MRSA isolates

Introduction

The epidemiology of S. aureus depends on conditions in specific populations. Few studies of S. aureus colonization in the older population have been performed in Spain. The aim of this study was to determine the prevalence of methicillin-resistant S. aureus (MRSA) colonization and its molecular epidemiological characteristics in an institutionalized population in community residential care homes in Cadiz, Spain.