Reducing methicillin-resistant Staphylococcus aureus (MRSA) patient exposure by infection control measures

INTRODUCTION: To assess the effectiveness of infection control measures (pre-admission screening and patient segregation) on reducing in-patient exposure to methicillin-resistant Staphylococcus aureus (MRSA). PATIENTS AND METHODS: A prospective case-control study in a district general hospital. All admissions to 3 wards over an 83-month period from September 1995 to July 2002 inclusive (a total of approximately 34,000 patients). Outcome measures were a statistical analysis of the difference in numbers of new cases of MRSA colonisation or infection between the 3 wards. RESULTS: There was a statistical significance in incidence of new MRSA cases between the ward with active infection control measures in place and the control wards. CONCLUSIONS: The described infection control measures reduced the exposure of patients to MRSA. This reduces the risk of MRSA infection, which is of importance in orthopaedics, and has further benefits that may also be applied in other surgical specialties.     

A prospective survey of current methicillin-resistant Staphylococcus aureus control measures.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is now endemic in tertiary referral hospitals among the developed world. By prospective survey, the effect of two measures aimed to reduce the spread of MRSA was determined. First, a surgical ward with persistently high levels of MRSA detection was cleaned and renovated. Second, the medical records of all MRSA-colonized patients were electronically flagged, facilitating immediate application of control measures on readmission. METHODS: Data were collected for 995 newly colonized patients admitted between 1 July 1995 and 31 December 1997. Methicillin-resistant Staphylococcus aureus detection was determined before and after implementation of the interventions, along with the likely place of MRSA acquisition and the monthly incidence of MRSA detection for all inpatients. Chi-squared testing with odds ratios and 95% confidence intervals determined associations between the effect of control measures studied and MRSA detection rates. RESULTS: New MRSA detection was 21.6 per 1000 admissions before refurbishment compared with 20.4 per 1000 admissions to the surgical ward after refurbishment. New MRSA detection averaged 6.4 per 1000 hospital admissions before the introduction of record flagging and patient cohorting, compared with 6.2 per 1000 admissions after. CONCLUSION: Neither ward refurbishment, nor introduction of flagging, significantly reduced rates of colonization during the study period. In hospitals that receive MRSA-colonized patients and provide intensive care facilities, spread of MRSA is a major problem. Effective containment demands separate wards for MRSA-colonized and non-colonized patients. The need for such containment should be considered in design of the modern hospital.     

Strategy to control methicillin-resistant Staphylococcus aureus post-operative infection in orthopaedic surgery

In the year 2000 the rate of infection after arthroplasty in our hospital was 9.75% and methicillin-resistant Staphylococcus aureus (MRSA) was the organism in 33% of the infected joints. In an attempt to overcome this unacceptable situation, we changed our prophylaxis regime over a period of 6 months. This involved modifying the precautionary measures for preventing surgical infections, active prophylaxis against any nasal reservoir of infection in joint implant patients, the control of health care personnel, the strict application of standard and contact precautions in all patients with MRSA, and the use of teicoplanin as prophylaxis during this 6-month period. This resulted in a definite decrease in the incidence of orthopaedic wound infections by MRSA, while the level of MRSA infection elsewhere in the hospital remained constant. Only one infection was detected during this 6-month trial, and this beneficial effect was maintained during the following 6 months. Since then, only sporadic new infections have been detected. Patients with arthroplasties performed during the study were followed for 12 months, and no new cases of MRSA infection were detected.     

Importance of methicillin-resistant Staphylococcus aureus eradication in carriers to prevent postoperative methicillin-resistant Staphylococcus aureus surgical site infection

Although infrequent, postoperative methicillin-resistant Staphylococcus aureus (MRSA) surgical site infection (SSI) is associated with significant morbidity and cost. Previous studies have identified the importance of MRSA screening to diminish the risk of postoperative MRSA SSI. The current study quantifies the importance of eradication of the MRSA carrier state to prevent MRSA SSI. Beginning February 2007, all admissions to an 800-bed tertiary care hospital were screened for MRSA by nasal swab using rapid polymerase chain reaction-based testing. Patients found to be nasal carriers of MRSA were treated with 2 per cent mupirocin nasal ointment and 4 per cent chlorhexidine soap before surgery. The subset of patients undergoing procedures that are part of the Surgical Care Improvement Project (SCIP) were followed for MRSA SSI (n = 8980). The results of preoperative MRSA screening and eradication of the carrier state were analyzed. Since the initiation of universal MRSA screening, 11 patients undergoing SCIP procedures have developed MRSA SSI (0.12%). Of these, six patients (55%) had negative preoperative screens. Of the five patients with positive preoperative screens, only one received treatment to eradicate the carrier state. In patients who develop MRSA SSI, failure to treat the carrier state before surgery results in MRSA SSI.     

Persistent and recurrent skin infection with small-colony variant methicillin-resistant Staphylococcus aureus

S. aureus is one of the problematic bacteria, capable to develop resistance mechanisms to all antibiotics that the bacteria are naturally susceptible. A particular phenotypic mechanism, especially against the antibiotics that repressed the synthesis of the cellular wall and aminoglycosides, was evidenced in subpopulations that grows in small-colonies and represents auxotrophic mutants for hemin, menadione or thymidine. This type of strains has been isolated most frequently from patients with osteomyelitis, septic arthritis or pulmonary infections after a long period of antibiotic treatment. The authors present the case of a patient with persistent and recurrent staphylococcal infection of the peritoneal dialysis exit site, treated with different antibiotics (ciprofloxacin, vancomycin, amoxicillin and clavulanic acid, cephalexin) from witch has been isolated a small-colony strain of methicillin-resistant S. aureus. Therapeutic failure can be explain by the slow multiplication of this strain in vivo, persistence into phagocytes and the protection offered by biofilm from the surface of the catheter. Bacteriologic diagnosis in these cases is difficult because of the culture, biochemical and susceptibility testing particularities of these strains. All these may lead failure to identification small colony variants of S. aureus and mis-evaluation of the frequency of infection with these strains in patients with long-term antibiotherapy.     

Nephrotoxicity of vancomycin in patients with methicillin-resistant Staphylococcus aureus bacteraemia

Aim: Vancomycin and teicoplanin are the two most used glycopeptides for the treatment of methicillin‐resistant Staphylococcus aureus (MRSA). Vancomycin is suspected to have more nephrotoxicity but this has not been clearly established. The aim of this study was to assess its nephrotoxicity by a consensus definition of acute kidney injury (AKI): the risk (R), injury (I), failure (F), loss and end‐stage renal disease (RIFLE) classification. Methods: Patients with MRSA bacteraemia who were prescribed either vancomycin or teicoplanin between 2003 and 2008 were classified. Patients who developed AKI were classified by RIFLE criteria. Variables such as comorbidities, laboratory data and medical cost information were also obtained from the database. Outcomes determined were: (i) the rate of nephrotoxicity and mortality; and (ii) the association of nephrotoxicity with the length of hospital stay and costs. Results: The study included 190 patients (vancomycin 33, teicoplanin 157). Fifteen patients on vancomycin and 27 patients on teicoplanin developed AKI (P = 0.0004). In the vancomycin group, four, eight and three patients were classified to RIFLE criteria R, I and F, respectively. In the teicoplanin group, 17, nine and one patient were classified to RIFLE criteria R, I and F, respectively. Kaplan–Meier analysis showed significant difference in time to nephrotoxicity for the vancomycin group compared to the teicoplanin group. No significant differences were found between the groups in terms of total mortality, length of hospital stay and costs. Conclusion: The study data suggest that vancomycin is associated with a higher likelihood of nephrotoxicity using the RIFLE classification.     

Improved management of infrainguinal bypass graft infection with methicillin-resistant Staphylococcus aureus

BACKGROUND: There is considerable debate over the management of infected infrainguinal grafts. This report describes recent experience in this field and documents the change in clinical practice needed to deal with methicillin-resistant Staphylococcus aureus (MRSA). METHODS: All infected infrainguinal grafts between January 1991 and July 1997 were reviewed. In the light of the findings, clinical practice was modified considerably. A further 1 year was audited prospectively up to August 1998. RESULTS: Twenty-six patients were treated for 27 infrainguinal graft infections (25 prosthetic, two vein). Twenty were treated by complete graft excision as the initial therapy; graft preservation was attempted in six patients. Before 1995, the infecting organisms were predominantly Pseudomonas aeruginosa or methicillin-sensitive staphylococci. Subsequently all 14 patients treated up to 1997 had infection with MRSA. The overall amputation rate was 17 of 26; ten amputations were in patients with MRSA. Four patients died, all with MRSA sepsis. As a result of this experience a policy of complete isolation was adopted for all patients infected with MRSA. In the 12 months since this policy was introduced, 77 infrainguinal grafts (61 vein, 16 prosthetic) have been inserted. Two grafts (3 per cent) have become infected, necessitating graft excision and amputation. CONCLUSION: MRSA infection of an infrainguinal graft is a serious complication with high associated amputation and mortality rates. Isolation and barrier nursing appeared to contain the problem.     

Carriage of methicillin-resistant Staphylococcus aureus is associated with an increased risk of infection after liver transplantation

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of sepsis in patients with cirrhosis and after liver transplantation. The association between nasal carriage of MRSA and sepsis in these patients is unclear. The goal of this study was to investigate the relationship between MRSA carriage before liver transplantation and subsequent sepsis after transplantation. This was a retrospective study of 374 consecutive adults who underwent orthotopic liver transplantation between 1998 and 2001 and for whom full data were available. Of these, 157 had been screened for MRSA as part of a study assessing the prevalence of MRSA infection. All MRSA carriers were treated with nasal mupirocin and chlorhexidine baths. The records of MRSA carriers and noncarriers were analyzed for Child and Model for End-Stage Liver Disease (MELD) score, posttransplantation MRSA, and other infections and mortality. Of the 157 patients who had an MRSA screen, 35 patients were MRSA nasal carriers. These carriers had significantly greater MELD score (mean, 16.2 compared with 13.1; P = .02) and Child scores (mean, 10 versus 9; P = .001) than noncarriers. The incidence of posttransplantation MRSA infection was significantly higher in MRSA carriers (31% versus 9%; P = .002). The incidence of other posttransplantation infection was not significantly different in the two groups. There was no significant difference in survival between the two groups (1-year patient survival, 74% and 82%, respectively). Patients carrying MRSA are predisposed to an increased risk of sepsis after liver transplantation with a trend to increased mortality. Screening for MRSA should be considered in high-risk patients being assessed for liver transplantation. (Liver Transpl 2003;9:754-759.)     

Eradication of persistent methicillin-resistant Staphylococcus aureus infection in cystic fibrosis

BackgroundThe prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in individuals with cystic fibrosis (CF) has increased significantly. While studies demonstrate that persistent MRSA infection in CF is associated with poor clinical outcomes, there are no randomized controlled studies informing management.MethodsThe Persistent MRSA Eradication Protocol was a double-blind, randomized, placebo-controlled study investigating a comprehensive 28-day treatment regimen with or without inhaled vancomycin for eradication of MRSA. Eligible participants had CF and documented persistent MRSA infection. All participants received oral antibiotics, topical decontamination, and environmental cleaning and were randomized to receive inhaled vancomycin or inhaled placebo. The primary outcome was the difference in MRSA eradication rates one month after completion of the treatment protocol.Results29 participants were randomized. Four subjects in the inhaled vancomycin group required withdrawal from the study for bronchospasm before outcome data were collected and were excluded from analysis. There was no difference in the primary outcome: 2/10 (20%) of subjects in the intervention group and 3/15 (20%) in the placebo group had a MRSA negative sputum culture one month after treatment. There were no statistically significant differences in the rates of MRSA eradication at the end of treatment or three months after treatment completion.ConclusionsThis study suggests that persistent MRSA infection is difficult to eradicate, even with multimodal antibiotics. The use of a single course of inhaled vancomycin may not lead to higher rates of MRSA eradication in individuals with CF and may be associated with bronchospasm.FundThis trial was financially supported by the Cystic Fibrosis Foundation.     

Favorable outcome of crescentic IgA nephropathy associated with methicillin-resistant Staphylococcus aureus infection

Dominant or codominant IgA deposits in the setting of proliferative glomerulonephritis usually indicate IgA nephropathy, Henoch-Sch?nlein purpura nephritis, or, sometimes, lupus nephritis. However, a new type of poststaphylococcal glomerulonephritis with predominantly IgA deposition has been increasingly reported. Herein, we report an unusual case of rapidly progressive glomerulonephritis following methicillin-resistant Staphylococcus aureus infection. Renal biopsy showed crescentic IgA nephropathy. The renal function improved after eradication of infection and administration of immunosuppressive therapy. Although the limited data support the use of immunosuppressive agents in this setting, one must proceed with caution. We suggest that immunosuppressive therapy should only be an option if the underlying infection has definitely been well controlled while the renal disease still progresses.     

Surgical site infection with methicillin-resistant Staphylococcus aureus after primary total hip replacement

We have analysed the management and clinical outcome of a series of consecutive patients who had a total hip replacement and developed post-operative surgical site infection (SSI) with methicillin-resistant Staphylococcus aureus. The incidence of this infection was 1% over a period of five years. We studied SSI in 15 patients (16 infections) with a mean age of 72.7 years (53 to 81). In all, 12 of the infections occurred early and half of the infections involved the prosthesis, resulting in an increase of 11-fold in the cumulative hospital stay. Methicillin-resistant Staph. aureus was successfully eradicated in all the patients after a mean follow-up of 53.6 months (25 to 88). Superficial incisional infections resolved after antibiotic therapy alone while deep infections required multiple operative debridements. Attempted retention of the implant in early organ space infections was successful in only one of five patients. Only three patients with implant-level infections obtained a pain-free, functional prosthesis while a further three required excision arthroplasty. We have formulated a protocol of treatment which may serve as a guide in the management of these infections.     

Risk factors for persistent methicillin-resistant Staphylococcus aureus infection in cystic fibrosis

Background

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as an important pathogen in cystic fibrosis (CF). Over 25% of individuals in the United States with CF are found to have MRSA in respiratory culture specimens, and persistent MRSA infection has been associated with more rapid decline in lung function and increased mortality. The objective of this study was to investigate clinical and demographic characteristics that are associated with the development of persistent MRSA infection in a CF population.

Postoperative wound infection with methicillin-resistant staphylococci in general surgical patients

A prospective survey of 1757 general surgical patients undergoing operation was performed comparing 35 patients with wound infection yielding methicillin-resistant Staphylococcus aureus (MRSA) with 184 patients developing wound infections due to other organisms. The following parameters were statistically significantly increased in the patients with MRSA wound infection; MRSA infection or colonization at other sites, 37% versus 2%, severe wound infection 31% versus 12%, wound drain tubes 23% versus 10%, multiple operations 37% versus 6%, malignant disease 43% versus 23%, postoperative complications 46% versus 16%, intensive care admissions 23% versus 5% and prophylactic antibiotics 51% versus 30%. There was no difference in postoperative mortality 11% versus 7%; mean age, 58 years versus 56 years; sex; diabetes, 11% versus 9%; or emergency operations 40% versus 39%. There were 18 patients with single organism MRSA wound infection who were compared with 35 patients with single organism methicillin-sensitive S. aureus (MSSA) wound infection. The patients with MRSA wound infections had a statistically significant increase in the following parameters: mean preoperative stay in hospital 8 days versus 4 days; prophylactic antibiotics 39% versus 3%; MRSA infection or colonization at other sites 39% versus 6%; and malignant disease 44% versus 17%. There were no deaths in either group and there was no statistically significant difference in other parameters, namely, multiple operations 11% versus 3%; intensive care admissions 6% in each group; wound drain tube 17% versus 11%; severe infections 22% versus 6%; and postoperative complications 22% versus 9%. These latter parameters were statistically significantly increased when all MRSA wound infections were compared with all wound infections due to other organisms.     

Cytokines and T-cell responses in superantigen-related glomerulonephritis following methicillin-resistant Staphylococcus aureus infection.

BACKGROUND: We have previously reported that 10 patients who developed glomerulonephritis (GN) in association with methicillin-resistant Staphylococcus aureus (MRSA) infection showed a marked increase in DR+CD4+ and DR+CD8+ subsets of T cells and in T cells expressing several T-cell receptor (TCR) V beta+cells, perhaps representing V beta-specific T-cell activation by MRSA-derived superantigens (Kidney Int 1995; 47: 207-216). In this study we examine cytokine levels, T-lymphocyte subsets, natural killer NK cells, memory T cells, and the expression of IL-2 receptors in order to better understand the role of bacterial superantigens and cytokines in the pathogenesis of MRSA-associated GN. METHODS: Twenty-two patients with MRSA infection who later developed GN caused by staphylococcal enterotoxin were evaluated immunologically in comparison with patients whose MRSA infection was not followed by GN (non-GN group) and normal individuals. RESULTS: Among peripheral lymphocytes, the frequency of T cells expressing several TCR V betas, especially V beta 5-family TCR, was higher in the GN group than in both the non-GN group and the normal healthy control group. GN patients also showed increased serum levels of several cytokines, including tumour necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), IL-2, IL-6, IL-8, and IL-10, which have been implicated in the onset of nephritis. Memory cells, and IL-2 receptors also were elevated in the GN group. CONCLUSION: These results suggest that T cells activated by MRSA-derived staphylococcal enterotoxins and subsequent production of cytokines may play an important role in the pathogenesis of MRSA-associated GN.     

Surgical treatment of methicillin-resistant Staphylococcus aureus infection following infrainguinal arterial reconstruction.

A 64-year-old man was referred to our hospital with Methicillin-resistant Staphylococcus aureus (MRSA) infection following infrainguinal arterial reconstruction. As repeated MRSA sepsis occurred, we decided to remove the infected graft with distal revascularization via circuitous graft tunneling to avoid serious infections and allow limb salvage. An iliofemoro bypass was performed via an extra-anatomical bypass, from just below the iliac crest into the musculus quadriceps femoris using an 8 mm-ringed polyester gelatin polypropylene tube graft, with complete debridement of a groin infection. Postoperative 3-dimentional CT angiography revealed that the prostheses was patent and the patient had an uneventful postoperative course. We concluded that this extra-anatomical bypass was a safe procedure and an excellent option for patients with an infected vascular prosthetic graft in the groin after previous revascularization, like in our case with no available autogeneous vein grafts.