Prevalence of methicillin-resistant Staphylococcus aureus nasal carriage among patients with femoral neck fractures: implication for antibiotic prophylaxis

Methicillin-Resistant Staphylococcus Aureus Carrier Rate in Orthopaedic Trauma Patients: A Prospective Cohort Study

OBJECTIVES

To identify the methicillin-resistant Staphylococcus aureus (MRSA) carrier rate among surgical patients on an orthopaedic trauma service and to determine whether screening is an effective tool for reducing postoperative MRSA infection in this population.

DESIGN

Prospective.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Two hundred forty-eight patients with operatively managed orthopaedic trauma conditions during the study period. Two hundred three patients (82%) had acute orthopaedic trauma injuries. Forty-five patients (18%) underwent surgery for a nonacute orthopaedic trauma condition, including 36 elective procedures and 9 procedures to address infection.

INTERVENTION

MRSA screening protocol, preoperative antibiotics per protocol.

MAIN OUTCOME MEASUREMENTS

MRSA carrier rate, overall infection rate, MRSA infection rate.

RESULTS

Our screening captured 71% (175/248) of operatively treated orthopaedic trauma patients during the study period. The overall MRSA carrier rate was 3.4% (6/175). When separated by group, the acute orthopaedic trauma cohort had an MRSA carrier rate of 1.4% (2/143), and neither MRSA-positive patient developed a surgical site infection. Only one MRSA infection occurred in the acute orthopaedic trauma cohort. The nonacute group had a significantly higher MRSA carrier rate of 12.5% (4/32, P = 0.01), and the elective group had the highest MRSA carrier rate of 15.4% (4/26, P < 0.01). The odds ratio of MRSA colonization was 10.1 in the nonacute group (95% confidence interval, 1.87-75.2) and 12.8 for true elective group (95% confidence interval, 2.36-96.5) when compared with the acute orthopaedic trauma cohort.

CONCLUSIONS

There was a low MRSA colonization rate (1.4%) among patients presenting to our institution for acute fracture care. Patients undergoing elective surgery for fracture-related conditions such as nonunion, malunion, revision surgery, or implant removal have a significantly higher MRSA carrier rate (15.4%) and therefore may benefit from MRSA screening. Our results do not support routine vancomycin administration for orthopaedic trauma patients whose MRSA status is not known at the time of surgery.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Review of MRSA screening and antibiotics prophylaxis in orthopaedic trauma patients; The risk of surgical site infection with inadequate antibiotic prophylaxis in patients colonized with MRSA

AIMS

The primary aim of this study was to determine whether orthopaedic trauma patients receive appropriate antibiotic prophylaxis keeping in view the results of their MRSA screening. The secondary aim was to analyse the risk of developing MRSA surgical site infection with and without appropriate antibiotic prophylaxis in those colonized with MRSA.

PATIENTS AND METHODS

We reviewed 400 consecutive orthopaedic trauma patient episodes. Preoperative MRSA screening results, operative procedures, prophylactic antibiotics and postoperative course were explored. In addition to these consecutive patients, the hospital MRSA database over the previous 5 years identified 27 MRSA colonized acute trauma patients requiring surgery.

RESULTS

Of the 400 consecutive patient episodes, 395(98.7%) had MRSA screening performed on admission. However, in 236 (59.0%) cases, the results were not available before the surgery. Seven patient episodes (1.8%) had positive MRSA colonization. Analysis of 27 MRSA colonized patients revealed that 20(74%) patients did not have the screening results available before the surgery. Only 5(18.5%) received Teicoplanin and 22(81.4%) received cefuroxime for antibiotic prophylaxis before their surgery. Of those receiving cefuroxime, five (22.73%) patients developed postoperative MRSA surgical site infection (SSI) but none of those (0%) receiving Teicoplanin had MRSA SSI. The absolute risk reduction for SSI with Teicoplanin as antibiotic prophylaxis was 22.73% (CI=5.22%-40.24%) and NNT (Number Needed to Treat) was 5 (CI=2.5-19.2) CONCLUSION: Lack of available screening results before the surgery may lead to inadequate antibiotic prophylaxis increasing the risk of MRSA surgical site infection. Glycopeptide (e.g.Teicoplanin) prophylaxis should be considered when there is history of MRSA colonization or MRSA screening results are not available before the surgery.

Surgical Site Infection After Surgery to Repair Femoral Neck Fracture: A French Multicenter Retrospective Study

Objective.

Femoral neck fracture is the most frequent orthopedic emergency among elderly persons. Despite a high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage in this population, no multicenter study of antibiotic prophylaxis practices and the rate and microbiological characteristics of surgical site infection (SSI) has been performed in France.

Design.

Retrospective, multicenter cohort study.

Setting.

Twenty-two university and community hospitals in France.

Patients.

Each center provided data on 25 consecutive patients who underwent surgery for femoral neck fracture during the first quarter of 2005. Demographic, clinical, and follow-up characteristics were recorded, and most patients had a follow-up office visit or were involved in a telephone survey 1 year after surgery.

Results.

These 22 centers provided data on 541 patients, 396 (73%) of whom were followed up 1 year after surgery. Of 504 (93%) patients for whom antibiotic prophylaxis was recorded, 433 (86%) received a cephalosporin. Twenty-two patients had an SSI, for a rate of 5.6% (95% confidence interval, 3.7-8.0). SSI was reported for 15 (6.9%) of patients who had a prosthesis placed and for 7 (3.9%) who underwent osteosynthesis (P = .27). SSI was diagnosed a median of 30 days after surgery (interquartile range, 21-41 days); 7 (32%) of these SSIs were superficial infections, and 15 (68%) were deep or organ-space infections. MRSA caused 7 SSIs (32%), Pseudomonas aeruginosa caused 5 (23%), other staphylococci caused 4 (18%), and other bacteria caused 2 (9%); the etiologic pathogen was unknown in 4 cases (18%). Reoperation was performed for 14 patients with deep or organ-space SSI, including 6 of 7 patients with MRSA SSI. The mortality rate 1 year after surgery was 20% overall but 50% among patients with SSI. In univariate analysis, only the National Nosocomial Infections Surveillance System risk index score was significantly associated with SSI (P = .006).

Conclusions.

SSI after surgery for femoral neck fracture is severe, and MRSA is the most frequently encountered etiologic pathogen. A large, multicenter prospective trial is necessary to determine whether the use of antibiotic prophylaxis effective against MRSA would decrease the SSI rate in this population.

A systematic literature review and meta-analysis of factors associated with methicillin-resistant Staphylococcus aureus colonization at time of hospital or intensive care unit admission

OBJECTIVE

Screening for methicillin-resistant Staphylococcus aureus (MRSA) in high-risk patients is a legislative mandate in 9 US states and has been adopted by many hospitals. Definitions of high risk differ among hospitals and state laws. A systematic evaluation of factors associated with colonization is lacking. We performed a systematic review of the literature to assess factors associated with MRSA colonization at hospital admission.

DESIGN

We searched MEDLINE from 1966 to 2012 for articles comparing MRSA colonized and noncolonized patients on hospital or intensive care unit (ICU) admission. Data were extracted using a standardized instrument. Meta-analyses were performed to identify factors associated with MRSA colonization.

RESULTS

We reviewed 4,381 abstracts; 29 articles met inclusion criteria (n = 76,913 patients). MRSA colonization at hospital admission was associated with recent prior hospitalization (odds ratio [OR], 2.4 [95% confidence interval (CI), 1.3-4.7]; P < .01), nursing home exposure (OR, 3.8 [95% CI, 2.3-6.3]; P < .01), and history of exposure to healthcare-associated pathogens (MRSA carriage: OR, 8.0 [95% CI, 4.2-15.1]; Clostridium difficile infection: OR, 3.4 [95% CI, 2.2-5.3]; vancomycin-resistant Enterococci carriage: OR, 3.1 [95% CI, 2.5-4.0]; P < .01 for all). Select comorbidities were associated with MRSA colonization (congestive heart failure, diabetes, pulmonary disease, immunosuppression, and renal failure; P < .01 for all), while others were not (human immunodeficiency virus, cirrhosis, and malignancy). ICU admission was not associated with an increased risk of MRSA colonization (OR, 1.1 [95% CI, 0.6-1.8]; P = .87).

CONCLUSIONS

MRSA colonization on hospital admission was associated with healthcare contact, previous healthcare-associated pathogens, and select comorbid conditions. ICU admission was not associated with MRSA colonization, although this is commonly used in state mandates for MRSA screening. Infection prevention programs utilizing targeted MRSA screening may consider our results to define patients likely to have MRSA colonization.

Is prophylactic Gentamicin associated with acute kidney injury in patients undergoing surgery for fractured neck of femur?

BACKGROUND

Single dose Gentamicin (240 mg) has been shown to reduce postoperative wound infection in patients with fractured neck of femur when used in a combined antibiotic regimen. However, concerns have arisen about the risk of acute kidney injury (AKI) in these patients.

OBJECTIVE

To determine if the use of prophylactic Gentamicin is associated with AKI in fractured neck of femur patients.

METHODS

A historical cohort study. Pre- and post-operative creatinine mmol/l of 100 successive fractured neck of femur patients admitted from September 2010 were compared to a control of 100 age, sex and procedure matched individuals operated upon before the introduction of prophylactic Gentamicin (2005). AKI was defined as an increase in serum creatinine by over 50% of base line. Statistical significance was regarded as p<0.05.

RESULTS

A significant rise in creatinine levels was observed in both control (p=0.005) and study groups (p=0.001). There was neither a significant difference in peak creatinine between groups (p=0.87) nor in rates of AKI (p=0.568) between the 2 groups.

CONCLUSION

Single preoperative doses of Gentamicin (240 mg) have no detrimental impact on renal function in this group. There is, however, a significant rise in creatinine following fractured neck of femur surgery, independent of Gentamicin.

The screening of methicillin-resistant staphylococcus aureus in vascular surgery patients: a comparison of molecular testing and broth-enriched culture

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is a major global health care-associated pathogen. This study sought to examine the prevalence of MRSA in patients who were admitted to a vascular surgery ward during a 3-month period.

METHODS

MRSA screening was accomplished through the acquisition of nasal, throat and perineal swabs. These swabs were placed in tryptic soy broth that had been supplemented with 6.5% NaCl and incubated for 24 h. The resulting isolates were subcultured on agar plates containing 5% sheep blood. The BD GeneOhm MRSA assay for screening swabs was performed in accordance with the manufacturer's instructions.

RESULTS

A total of 58 patients were included in the study and swabs from 232 sites were obtained during the sampling period. MRSA was detected in 33 samples of 12 patients during the study period; thus, there was a 20.6% prevalence of patients who were recognized as MRSA carriers. There were discrepancies between the results of classical bacteriological screening and molecular MRSA detection methods in 8 of the patients.

CONCLUSIONS

Nasal, throat and perineal MRSA screening can detect the carriage of this pathogen and allow for the timely use of appropriate infection control measures. The choice of screening techniques poses a challenge; it has been demonstrated that molecular detection methods should be performed with great sensitivity, specificity and, most importantly, speed. The cost of the PCR screening method is the only disadvantage of this approach.

MRSA colonisation in patients with proximal femur fractures in a German trauma centre: incidence, infection rates and outcomes

PURPOSE

The aim of this study was to assess the incidence of methicillin-resistant Staphylococcus aureus (MRSA) colonisation in patients admitted into a level 1 German trauma centre with proximal femur fractures, to correlate this incidence with defined risk factors for MRSA colonisation and to determine its influence on morbidity and mortality.

METHODS

Between August and November 2006, 65 patients were included in the study. Cotton-tipped swab samples were taken from the nose, throat, groin and any skin defects in the emergency room. The following factors were recorded: age, gender, any concomitant diseases, the fracture type and treatment device, skin lesions, hospitalisation within the last year, any urinary or vascular catheters, a nasogastric or gastrostomy tube, an ileal stoma, the use of a respirator and antibiotic therapy within the last year. During follow-up, data concerning any surgical site infections; any chest, urinary or vascular catheter infections; the success of decontamination and death within 1 year after surgery were collected.

RESULTS

The risk factors for MRSA colonisation were positive in 40 patients. The incidence of MRSA colonisation was 17%, which is higher than in most comparable studies but consistent with some very recent publications. The nosocomial infection rates, surgical site infection rates and mortality within the 1-year follow-up period were significantly higher in the MRSA-colonised patients.

CONCLUSION

The high incidence of MRSA in this study supports the need for systematic detection of MRSA-colonised patients. In our hospital, any patient with positive risk factors for MRSA colonisation is swabbed in the emergency room and treated as MRSA positive until proven otherwise.

A simple prophylaxis regimen for MRSA: its impact on the incidence of infection in patients undergoing liver resection

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) infection has increased at an alarming rate in the recent past and has major cost implications. The aim of this study is to assess the impact of a policy of pre-operative MRSA prophylaxis on the incidence of MRSA infection in patients undergoing liver resection.

PATIENTS AND METHODS

A total of 585 patients underwent hepatectomy in a tertiary referral centre between January 2000 and September 2005. In September 2003, a policy of MRSA prophylaxis (nasal mupirocin and triclosan wash for 5 days) was introduced within this unit. Demographic, pathological and outcome data were compared between the pre- and post-MRSA prophylaxis cohorts.

RESULTS

The prevalence of MRSA infection prior to initiating the prophylaxis protocol was 29 patients (8.3%) and this fell to 9 patients (3.8%; P = 0.029). Furthermore, patients who had MRSA-related infection had a higher incidence of additional complications compared to the rest of the cohort (P = 0.001). Total cost savings incurred as a result of this protocol over the past 2 years has been approximated at 28,893 pounds.

CONCLUSIONS

Introduction of a simple MRSA prophylaxis policy has had a significant reduction on the incidence MRSA-related infection within our patient population, leading to reduced morbidity and cost saving to the UK National Health Service.

Methicillin-resistant Staphylococcus aureus in orthopaedic surgery

Methicillin-resistant Staphylococcus aureus (MRSA) has become a ubiquitous bacterium in both the hospital and community setting. There are two major subclassifications of MRSA, community-acquired and healthcare-acquired, each with differing pathogenicity and management. MRSA is increasingly responsible for infections in otherwise healthy, active adults. Local outbreaks affect both professional and amateur athletes and there is increasing public awareness of the issue. Health-acquired MRSA has major cost and outcome implications for patients and hospitals. The increasing prevalence and severity of MRSA means that the orthopaedic community should have a basic knowledge of the bacterium, its presentation and options for treatment. This paper examines the evolution of MRSA, analyses the spectrum of diseases produced by this bacterium and presents current prevention and treatment strategies for orthopaedic infections from MRSA.

Comparison of routine prophylaxis with vancomycin or cefazolin for femoral neck fracture surgery: microbiological and clinical outcomes

OBJECTIVE

To assess the impact of antibiotic prophylaxis on the emergence of vancomycin-resistant strains of Enterococcus faecium, Enterococcus faecalis, and Staphylococcus aureus and the incidence of surgical site infection (SSI) after vancomycin or cefazolin prophylaxis for femoral neck fracture surgery.

DESIGN

Prospective cohort study.

SETTING

A hospital with a high prevalence of methicillin-resistant S. aureus (MRSA) carriage.

PATIENTS

All patients admitted with a femoral neck fracture from March 1, 2004 through February 28, 2005 were prospectively identified and screened for MRSA and vancomycin-resistant (VRE) carriage at admission and at day 7. Deep incisional and organ/space SSIs were also recorded.

RESULTS

Of 263 patients included in the study, 152 (58%) received cefazolin and 106 (40%) received vancomycin. At admission, the prevalence of MRSA carriage was 6.8%; it was 12% among patients with risk factors and 2.2% among patients with no risk factors (P=.002). At day 7 after surgery, there were 6 patients (2%) who had hospital-acquired MRSA, corresponding to 0.7% in the cefazolin group and 5% in the vancomycin group (P=.04); none of the MRSA isolates were resistant to glycopeptides. The rate of VRE carriage at admission was 0.4%. Three patients (1%) had acquired carriage of VRE (1 had E. faecium and 2 had E. faecalis); all 3 were in the cefazolin group (2% of patients) and none in the vancomycin group (P=.27). Eight SSIs (3%) occurred, 4% in the cefazolin group and 2% in the vancomycin group (P=.47).

CONCLUSIONS

This preliminary study demonstrates that cefazolin and vancomycin prophylaxis have similar impacts on the emergence of glycopeptide-resistant pathogens. Neither MRSA infection nor increased rates of SSI with other bacteria were observed in the vancomycin group, suggesting that a larger multicenter study should be initiated.

Nasal Carriage of Methicillin-Resistant Staphylococcus aureus in Vascular Surgery

The purpose of this study was to determine the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) and to define risk factors allowing identification of high-risk patients for MRSA nasal carriage at admission to the vascular surgery unit. From March 23, 2004 to July 13, 2004, screening for nasal carriage of MRSA was conducted at admission to the vascular surgery unit and 1 week thereafter. To analyze risk factors for MRSA nasal carriage at admission to the vascular surgery unit, a case-control study was carried out in patients presenting colonization at the time of admission. A total of 308 patients underwent nasal screening for MRSA. Thirteen were colonized with MRSA (nine at admission and four acquired), i.e., 4.2% of patients. Methicillin-susceptible Staphylococcus aureus (MSSA) was found in 11.4% of patients who underwent screening. Six patients with MRSA infection were identified during the study period. The two patients who acquired infection were colonized at the time of admission. Arrival from another health-care facility and from another department was a significant risk factor for carriage of MRSA. The prevalence of nasal carriage in vascular surgery was 4.2%. Nasal screening is highly cost-effective since 60% of MRSA carriers were undetected using diagnostic specimens alone. French recommendations issued for cardiac and orthopedic surgery by the consensus conference on preoperative management of infectious risk on March 5, 2004, should be extended to vascular surgery.

[Detection of nasal colonization methicillin-resistant Staphylococcus aureus: a prospective study comparing real-time genic amplification assay vs selective chromogenic media]

In contrast to "classical" genic amplification, real-time genic amplification can be performed in every laboratory without the need of sophisticated isolation procedures. Moreover, real-time genic amplification allows an early detection of meticillin resistant Staphylococcus aureus colonization, 2 hours compared to 1 or 2 days for culture.

OBJECTIVE

In order to assess the feasibility on Smartcycler of the IDI-MRSA real-time genic amplification assay in comparison with chromogenic media.

METHODS

A prospective study has been initiated in July 2004: nasal swabs were taken from patients entering the ICU, vascular surgery, diabetology and geriatry wards. During a 4 months period, 682 specimens have been obtained from 508 patients.

RESULTS

Sixty-four (9.3%) patients were positive by genic amplification and selective agar culture (CHROMagar MRSA, MRSASelect and/or ORSAB), 19 (2.9%) were positive by genic amplification only (3 of these patients were under antibiotic treatment); 572 specimens remained negative by both methods. The sensitivity and specificity of this assay were 100% and 96% respectively with a positive predictive value of 70% and negative predictive value of 100%. Initially 82 nasal specimens were unresolved (12%). 38 were resolved following a freeze-thaw cycle. Thus, 44 (6.4%) were unresolved specimens. Comparison between CHROMagar MRSA and MRSASelect showed a good correlation for the detection at 24 hours (5.5% and 5.6% respectively). These two chromogenic media allowed a much better detection of MRSA than ORSAB medium within 24H.

CONCLUSION

The results obtained by the early real-time genic amplification for the detection of meticillin resistant Staphylococcus aureus are promising. Despite 6.4% amplification failure, we consider that IDI-MRSA real-time genic amplification assay represents a significant breakthrough in the detection of colonization.

Guidelines for the prophylaxis and treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in the UK

These evidence-based guidelines have been produced after a literature review of the treatment and prophylaxis of methicillin-resistant Staphylococcus aureus (MRSA) infection. The guidelines were further informed by antibiotic susceptibility data on MRSA from the UK. Recommendations are given for the treatment of common infections caused by MRSA, elimination of MRSA from carriage sites and prophylaxis of surgical site infection. There are several antibiotics currently available that are suitable for use in the management of this problem and potentially useful new agents are continuing to emerge.

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.