Aims

The aim of this study was to determine whether the sequential application of povidone iodine-alcohol (PVI) followed by chlorhexidine gluconate-alcohol (CHG) would reduce surgical wound contamination to a greater extent than PVI applied twice in patients undergoing spinal surgery.

This longitudinal microCT study revealed the osteolytic response to a Staphylococcus epidermidis-infected implant in vivoand also demonstrates how antibiotics and/or a low bone mass state influence the morphological changes in bone and the course of the infection. Colonisation of orthopaedic implants with Staphylococcus aureusor S. epidermidisis a major clinical concern, since infection-induced osteolysis can drastically impair implant fixation or integration within bone. High fracture incidence in post-menopausal osteoporosis patients means that this patient group are at risk of implant infection. The low bone mass in these patients may exacerbate infection-induced osteolysis, or alter antibiotic efficacy. Therefore, the aims of this study were to examine the bone changes resulting from a S. epidermidisimplant infection in vivousing microCT imaging, and to determine if a low bone mass stateinfluences the course of the infection and the efficacy of antibiotic therapy. An in vivomodel system using microCT scanning [1], involving the implantation of either a sterile or a S. epidermidis-colonised PEEK screw into the proximal tibia of 24 week-old female Wistar rats, was used to investigate the morphological changes in bone following infection over a 28 day period. In addition, the efficacy of a combination antibiotic therapy (rifampin and cefazolin: administered twice daily from days 7–21 post-screw implantation) for affecting osteolysis was also assessed. A subgroup of animals was subjected to ovariectomy (OVX) at 12 weeks of age, allowing for a 12 week period for bone loss prior to screw implantation at 24 weeks. Bone resorption and formation rates, bone-implant contact and peri-implant bone volume in the proximity of the screw were assessed by microCT scanning at days 0, 3, 6, 9, 14, 20 and 28 days post-surgery. Following euthanasia at day 28, the implanted screw, bone and soft tissues were subjected to quantitative bacteriology as a measure of the efficacy of the antibiotic regimen. In non-OVX animals S. epidermidisinfection induced marked osteolysis, which peaked between 9 and 14 days post-screw implantation. Peak bone resorption was detected at day 6, before recovering to baseline levels at day 14. Infection also resulted in extensive deposition of mineralised tissue, initially within the periosteal region (day 9–14), then subsequently in the osteolytic region at day 20–28. Quantitative bacteriology indicated all non-OVX animals remained infected. Rifampin and cefazolin successfully cleared the infection in 5/6 non-OVX animals group although there was no difference observed in CT-derived bone parameters. OVX resulted in extensive loss of trabecular bone but this did not alter the temporal pattern of infection-induced osteolysis, or mineralised tissue deposition, which was similar to that observed in the non-OVX animals. Similarly, there was no difference in bacterial counts between non-OVX and OVX animals (39,005 colony-forming units (CFU) [range: 3,675–156,800] vs 37,665 CFU [range 3,250–84,000], respectively). Interestingly, antibiotic treatment was less effective in the OVX animals (3/5 remained infected), suggesting that antibiotics have reduced efficacy in OVX animals. This study demonstrates S. epidermidis-induced osteolysis displays a similar temporal pattern in both normal and low bone mass states, with comparable bacterial loads present within the localised infection site

1. Patient Factors. a. Intrinsic. i. Age. ii. Nutritional status. iii. Diabetes. iv. Smoking. v. Obesity. b. Coexistent infections at a remote body site. c. Altered immune response/Colonisation with microorganisms. d. Length of pre-op stay/institutionalisation. 2. Pre-Operative. a. Hand Prep/Scrub Duration/Technique. b. Skin antisepsis/Prep/Hair removal. c. Antimicrobial prophylaxis. 3. Operative. a. Ventilation. b. Instrument sterilisation. c. Surgery. i. Duration. ii. Poor hemostasis/Drains/Dead space. iii. Tissue trauma/Foreign material

Introduction

The concept of “bone graft expanders” has been popularised to increase the volume and biological activity of the implanted Material.

Purpose

Surgical site infection (SSI) is an infrequent but serious complication of total joint arthroplasty (TJA). Orthopaedic SSI causes substantial morbidity, prolonging the hospital stay by a median of 2 weeks, doubling the rates of rehospitalization, and more than tripling overall healthcare costs. Colonization with methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) is known to be associated with an increased risk of subsequent SSI. Carriers are two to nine times more likely to acquire S. aureus SSIs than non-carriers. Screening of the nose and throat for MRSA colonization and preoperative patient decolonization have been shown to decrease the incidence of subsequent MRSA infection. The aim of this study was to investigate the association between the results of MRSA colonization screening and the incidence of SSI in our hospital.

Staphylococcus aureus is one of the leading causes of surgical site infection (SSI). Over the past decade there has been an increase in methicillin-resistant S. aureus (MRSA). This is a subpopulation of the bacterium with unique resistance and virulence characteristics. Nasal colonisation with either S. aureus or MRSA has been demonstrated to be an important independent risk factor associated with the increasing incidence and severity of SSI after orthopaedic surgery. Furthermore, there is an economic burden related to SSI following orthopaedic surgery, with MRSA-associated SSI leading to longer hospital stays and increased hospital costs. Although there is some controversy about the effectiveness of screening and eradication programmes, the literature suggests that patients should be screened and MRSA-positive patients treated before surgical admission in order to reduce the risk of SSI.

Cite this article: Bone Joint J 2013;95-B:4–9.

The objective of this study was to determine the effectiveness of screening and successful treatment of methicillin-resistant Staphylococcus aureus (MRSA) colonisation in elective orthopaedic patients on the subsequent risk of developing a surgical site infection (SSI) with MRSA.

We screened 5933 elective orthopaedic in-patients for MRSA at pre-operative assessment. Of these, 108 (1.8%) were colonised with MRSA and 90 subsequently underwent surgery. Despite effective eradication therapy, six of these (6.7%) had an SSI within one year of surgery. Among these infections, deep sepsis occurred in four cases (4.4%) and superficial infection in two (2.2%). The responsible organism in four of the six cases was MRSA. Further analysis showed that patients undergoing surgery for joint replacement of the lower limb were at significantly increased risk of an SSI if previously colonised with MRSA.

We conclude that previously MRSA-colonised patients undergoing elective surgery are at an increased risk of an SSI compared with other elective patients, and that this risk is significant for those undergoing joint replacement of the lower limb. Furthermore, when an infection occurs, it is likely to be due to MRSA.

Introduction: The Rhys-Davies exsanguinator is a commonly used tool for exsanguinating upper or lower limbs in orthopaedic surgery. The use of same exsanguinators on a repetitive basis can cause cross contamination. This study was aimed at looking at the contamination of the Rhys-Davies exsanguinators in our hospital and comparing the results after cleaning it with a disinfectant wipe.

Materials and Methods: We used two standard methods to measure the contamination levels of the Rhys-Davies exsanguinators. In first method, we used rapid microbial ATP bioluminescence assay to detect contamination before and after cleaning of these exsanguinators. We did this test at four specified sites (outer top, outer bottom, inside top and inside bottom) after clearly marking them. Our second method was taking samples and using standard agar plates from the 24 sites of these 6 Rhys-Davies exsanguinators. We repeated the assay as well the swabs from all the sites, after cleaning these exsanguinators with Sani Cloth 70 Alcohol Wipes. We incubated these samples at 37 deg cel for 48 hours and kept them in enrichment cultures for 7 days.

Results: All sampled Rhys-Davies exsanguinators were heavily contaminated as revealed by both the methods. On bioluminescence assay, in some exsanguinators the count was 100 times more than normal (acceptable value is 30). Similarly all exsanguinators were colonised with bacterial count varying from 8 to > 350. Coagulase negative staphylococcus was the most commonly grown organism from the exsanguinators. After cleaning these tourniquets with Sani Cloth Wipes, there was 95% reduction in bioluminescence assay and 99% reduction in contamination from colony growth point of view, which is statistically significant (P=0.02).

Conclusion: Nine percent of hospital in-patients are believed to acquire an infection after their admission to hospital. Different organisms can raise different levels of concerns. Coagulase negative Staphylococcus from a skin swab is normal but it can be a major source for surgical site infections. The presence of any number of such organisms around a surgical site can be worrying. The presence of a single colony of other pathogenic organisms such as MRSA, Coliforms or Pseudomonas can be alarming if found on these devices. This study suggests that mechanical decontamination by cleaning with sani cloth wipes, then leaving it to dry completely for 15 minutes might reduce the level of contamination of these devices. Use of rapid R-mATP assay has added strength to our study as it requires only 5 min to complete, including sampling. This screening method can be used randomly to check whether protocols are being properly followed, regarding decontamination of such devices.

Introduction: Tourniquets are commonly employed in surgical procedures of the knee. The use of the same tourniquet on a repetitive basis without a standard protocol for cleaning has recently been questioned as a potential source of cross-infection. This study examines the contamination of the tourniquets in our institution and results of cleaning the tourniquets with a disinfectant and detergent wipe.

Material and methods: Tryptone soya agar plates were used to take samples from 20 tourniquets employed in knee replacement. Four specified sites on each tourniquet were cultured and incubated at 37° for 48 hrs.

Results: All sampled tourniquets were contaminated with colony counts varying from 9 to > 385.

Coagulase negative Staphylococcus was the most commonly grown organism from the tourniquets (96%).

Some tourniquets had growths of important pathogens including MRSA, Pseudomonas and Staphylococcus aureus (these organisms have not been previously cultured from tourniquets). On cleaning five tourniquets with clinell (detergent and disinfectant) wipes, there was a 99.2% reduction in contamination of the tourniquets five minutes after cleaning.

Conclusion: Contamination is more worrying in relation to pneumatic tourniquets, as they are commonly employed in knee surgery where implants are frequently used with the tourniquet lying within inches of the operative wound.

We have found a 99% reduction in contamination of tourniquets by employing disinfectant wipes. This is a simple, cost-effective and quick method to clean tourniquets and we recommend the use of wipes before every case in addition to the manufactures guidelines for general cleaning of tourniquets.

MRSA infections are a current concern in the elderly orthopaedic patient, with colonisation rates of between 417% reported in these patient groups. In our institution there has been concern regarding MRSA surgical site infection and cross contamination of elective and emergency patients. This prompted the unit to consider a screening programme to identify MRSA carriers. We undertook the following project to assess the feasibility and effectiveness of implementing such a screening programme.

The aim was to to ascertain the incidence of colonisation with MRSA, rate of wound infection and associated risk factors in patients admitted with a fractured proximal femur.

This was a prospective, blinded case series of 100 consecutive patients admitted to the trauma ward with a fractured proximal femur. Three swabs (axilla, nasal and perineum) were taken within 24 hours of admission. Data from each patient was collated and each patient was followed until discharge to assess for surgical site infection.

The age range was 60–97 years. 26% were admitted from institutional care. Four patients were colonised with MRSA on admission. An association was seen between patients colonised on admission and long term or recent residence in institutional care. One of these patients went on to develop colonisation of the surgical wound however this did not lead to surgical site infection and the patient was successfully treated with MRSA eradication therapy only. In these 4 patients all wounds healed satisfactorily with no evidence of infection.

While MRSA continues to be a growing concern in the press we found that rates of colonisation and subsequent infection were not high. There were no documented cases of MRSA wound infection in colonised individuals. Given the cost to detect these low levels of colonisation we do not feel that a screening regime would be cost effective or justified.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

Background: In recent years an increased trend in MRSA infection has been seen in hospitals and the community, with colonisation rates of between 4 – 17% reported in these patient groups. There is also an association between carriage of Staph. Aureus and staphylococcal surgical wound infection.

In our institution there has been concern regarding MRSA surgical site infection and possible cross contamination of elective and emergency patients. There would be implications for implant related infections if this were to occur. This had prompted the unit to consider adopting a screening programme to identify and treat MRSA carriers. This would aim to minimise risk of post operative infection and cross infection. As little was actually known about the MRSA colonisation rates of admissions to our hospital we undertook the following project to assess the feasibility and effectiveness of implementing such a screening programme.

Aim: To ascertain the incidence of colonisation with MRSA, rate of wound infection and the associated risk factors in patients admitted to the trauma ward with a fractured neck of femur.

Method: A prospective, blinded case series of 100 consecutive patients admitted to the trauma ward with a fractured neck of femur. Three swabs (axilla, nasal and perineum) were taken within 24 hours of admission. Data from each patient was collected to ascertain the presence of risk factors linked to MRSA colonisation and each patient was followed until discharged to assess for surgical site infection.

Results: 304 swabs were taken from 100 patients. Age range 60–97. 26% admitted from institutionalised care and 74% admitted from their own home. Four patients were colonised with MRSA on admission (2 nasal, 2 perineal). An association was seen between patients colonised on admission and long term or recent residence in institutionalised care. One of these patients went on to develop colonisation of the surgical wound however this did not lead to surgical site infection and the patient was successfully treated with MRSA eradication therapy only. In these 4 patients all wounds healed satisfactorily with no evidence of infection.

There were three superficial surgical site infections postoperatively, all in individuals who were clear on their admission screening. Of these two were due to MRSA and one was due to MSSA. There were no cases of deep infection requiring further surgery.

Conclusion:While MRSA continues to be a growing concern we found that, in our hospital, rates of MRSA colonisation and subsequent infection were not high. There were no documented cases of MRSA wound infection in colonised individuals. Given the cost involved in swabbing all patients to detect these low levels of colonisation we do not feel that an expensive screening regimen would be cost effective or justified in our institution.

We have conducted a case-control study over a period of ten years comparing both deep infection with methicillin-resistant staphylococcus aureus (MRSA) and colonised cases with a control group.

Risk factors associated with deep infection were vascular diseases, chronic obstructive pulmonary disease, admission to a high-dependency or an intensive-care unit and open wounds. Those for colonisation were institutional care, vascular diseases and dementia. Older age was a risk factor for any MRSA infection. The length of hospital stay was dramatically increased by deep infection.

These risk factors are useful in identifying higher-risk patients who may be more susceptible to MRSA infection. A strategy of early identification and isolation may help to control its spread in trauma units.

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.

Introduction: A recent JBJS(Br) article examined skin markers after contamination with a standard MRSA inoculum and cultured on MRSA-indicator nutrient agar. The Penflex™ marker showed no survival after 15 minutes, whereas the Viomedex™ marker produced MRSA cultures for up to three weeks.

Research undertaken at Wrightington has shown that in primary joint replacement coagulase-negative staphylococci account for 67.2% – 76% of contaminants isolated from the ultra clean zone. It is the most prevalent and persistent species on human skin and mucous membranes and accounts for 58% of failures due to deep infection of primary THR.

Further studies of nosocomial infection transmission show bacterial contamination of healthcare workers’ scissors, ballpoint pens, stethoscopes and lab coats with MRSA, VRE and gram-negative bacilli.

Multiuse skin markers may become colonised, possibly with MRSA, MRSE and gram-negative bacilli. This may contaminate patients and cause premature failure of arthroplasty, leading some units to adopt a single use policy.

Our aim was to ascertain bacterial colonisation of multiuse skin markers.

Method: Multiuse indelible skin markers were collected from Orthopaedic staff, wards and Day Surgery Units within the Mid-Yorkshire Hospitals.

Pens identified by a number, brand, location and approximate pen age.

Pen tips were neutralised with 10ml sterile Peptone water and this was used as the inoculum.

Cap interior swabbed with sterile swab (pre-dipped in sterile water).

Both were inoculated into enrichment broth and plated onto Blood and McConkey media.

Incubation at 37°c for 18 hours with plates read at 7 days for colony forming units.

Results: 31 pens. 15 different brands. Age 1 month– 3yrs

No growth on all plates after incubation for 7 days.

Conclusion: These results indicate that multiuse indelible skin markers are safe. There is no evidence to support subsequent cross contamination or the need for sterile single use pens for preoperative marking.

Patients admitted to trauma wards are routinely screened for MRSA pre-operatively. The majority of them have implant surgery before the screening results were available. The aim of our study was to identify the incidence of MRSA wound infection in these patients and their outcome following it.

We randomly reviewed 40 patients who were colonised with MRSA pre-operatively and have had implant surgeries. The case notes, drug charts and the microbiology were reviewed to identify the incidence of MRSA wound infection and its outcome in these patients. The place of residence, site of colonisation and the treatment given were also considered.

70% of the patients were admitted from home and 20% had previous admission within one year. The commonest site colonised is the nose (50%) followed by the perineum in 20%. Multiple sites were colonised in 10% of the patients. Only 50% of them with positive nasal MRSA were given nasal bactroban and chlohexidine wash was given in only 70% of them with MRSA colonisation in other areas. 22.5% (9/40) of the patients developed MRSA infection post operatively and they were treated with vancomycin or teicoplanin. Wound debridement and washout were done in 67.5%. 75% of the MRSA infected wound healed well with no MRSA in the wound site after treatment. 25% of the MRSA infected wounds had persistent MRSA in the wound.

As per our study the incidence of MRSA wound infection in patients colonised pre-operatively is about 22.5%. Most cases seem to heal well without much complication with appropriate antibiotics and wound care.

We examined the rates of infection and colonisation by methicillin-resistant Staphylococcus aureus (MRSA) between January 2003 and May 2004 in order to assess the impact of the introduction of an MRSA policy in October 2003, which required all admissions to be screened. Emergency admissions were treated prophylactically and elective beds ring-fenced. A total of 5594 admissions were cross-referenced with 22 810 microbiology results. The morbidity, mortality and cost of managing MRSA-carrying patients, with a proximal fracture of the femur were compared, in relation to age, gender, American Society of Anaesthesiologists grade and residential status, with a group of matched controls who were MRSA-negative.

In 2004, we screened 1795 of 1796 elective admissions and MRSA was found in 23 (1.3%). We also screened 1122 of 1447 trauma admissions and 43 (3.8%) were carrying MRSA. All ten ward transfers were screened and four (40%) were carriers (all p < 0.001). The incidence of MRSA in trauma patients increased by 2.6% per week of inpatient stay (r = 0.97, p < 0.001). MRSA developed in 2.9% of trauma and 0.2% of elective patients during that admission (p < 0.001). The implementation of the MRSA policy reduced the incidence of MRSA infection by 56% in trauma patients (1.57% in 2003 (17 of 1084) to 0.69% in 2004 (10 of 1447), p = 0.035). Infection with MRSA in elective patients was reduced by 70% (0.56% in 2003 (7 of 1257) to 0.17% in 2004 (3 of 1806), p = 0.06). The cost of preventing one MRSA infection was £3200.

Although colonisation by MRSA did not affect the mortality rate, infection by MRSA more than doubled it. Patients with proximal fractures of the femur infected with MRSA remained in hospital for 50 extra days, had 19 more days of vancomycin treatment and 26 more days of vacuum-assisted closure therapy than the matched controls. These additional costs equated to £13 972 per patient.

From this experience we have been able to describe the epidemiology of MRSA, assess the impact of infection-control measures on MRSA infection rates and determine the morbidity, mortality and economic cost of MRSA carriage on trauma and elective orthopaedic wards.