Methicillin-resistant Staphylococcus aureus in orthopaedic trauma

Asymptomatic and yet C. difficile-toxin positive? Prevalence and risk factors of carriers of toxigenic Clostridium difficile among geriatric in-patients

Background

Clostridium difficile infections (CDI) are the most frequent cause of diarrhoea in hospitals. Geriatric patients are more often affected by the condition, by a relapse and complications. Therefore, a crucial question is how often colonization with toxigenic Clostridium difficile strains occurs in elderly patients without diarrhoea and whether there is a “risk pattern” of colonized patients that can be defined by geriatric assessment. Furthermore, the probability for those asymptomatic carriers to develop a symptomatic infection over time has not been sufficiently explored.

Methods

We performed a cohort study design to assess the association of clinical variables with Clostridium difficile colonization. The first stool sample of 262 consecutive asymptomatic patients admitted to a geriatric unit was tested for toxigenic Clostridium difficile using PCR (GeneXpert, Cepheid). A comprehensive geriatric assessment (CGA) including Barthel Index, Mini Mental State Examination (MMSE) and hand grip-strength was performed. In addition, Charlson Comorbidity Index, body mass index, number and length of previous hospital stays, previous treatment with antibiotics, institutionalization, primary diagnoses and medication were recorded and evaluated as possible risk factors of colonization by means of binary logistic regression. Secondly, we explored the association of C. difficile colonization with subsequent development of CDI during hospital stay.

Results

At admission, 43 (16.4%) patients tested positive for toxin B by PCR. Seven (16.3%) of these colonized patients developed clinical CDI during hospital stay, compared to one out of 219 patients with negative or invalid PCR testing (Odds ratio 12,3; Fisher’s exact test: p = 0.000). Overall, 7 out of 8 (87.5%) CDI patients had been colonized at admission. Risk factors of colonization with C. difficile were a history of CDI, previous antibiotic treatment and hospital stays. The parameters of the CGA were not significantly associated with colonization.

Conclusion

Colonization with toxigenic Clostridium difficile strains occurs frequently in asymptomatic patients admitted to a geriatric unit. Previous CDI, antibiotic exposure and hospital stay, but not clinical variables such as CGA, are the main factors associated with asymptomatic Clostridium difficile carriage. Colonization is a crucial risk factor for subsequent development of symptomatic CDI.

Healthcare Associated Infections of Methicillin-Resistant Staphylococcus aureus: A Case-Control-Control Study

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most widespread and dangerous pathogens in healthcare settings. We carried out this case-control-control study at a tertiary care hospital in Guangzhou, China, to examine the antimicrobial susceptibility patterns, risk factors and clinical outcomes of MRSA infections.

METHODS

A total of 57 MRSA patients, 116 methicillin-susceptible Staphylococcus aureus (MSSA) patients and 102 S. aureus negative patients were included in this study. We applied the disk diffusion method to compare the antimicrobial susceptibilities of 18 antibiotics between MRSA and MSSA isolates. Risk factors of MRSA infections were evaluated using univariate and multivariate logistic regression models. We used Cox proportional hazards models and logistic regression analysis to assess the hospital stay duration and fatality for patients with MRSA infections.

RESULTS

The MRSA group had significantly higher resistance rates for most drugs tested compared with the MSSA group. Using MSSA patients as controls, the following independent risk factors of MRSA infections were identified: 3 or more prior hospitalizations (OR 2.8, 95% CI 1.3-5.8, P = 0.007), chronic obstructive pulmonary disease (OR 5.9, 95% CI 1.7-20.7, P = 0.006), and use of a respirator (OR 3.6, 95% CI 1.0-12.9, P = 0.046). With the S. aureus negative patients as controls, use of a respirator (OR 3.8, 95% CI 1.0-13.9, P = 0.047) and tracheal intubation (OR 8.2, 95% CI 1.5-45.1, P = 0.016) were significant risk factors for MRSA infections. MRSA patients had a longer hospital stay duration and higher fatality in comparison with those in the two control groups.

CONCLUSIONS

MRSA infections substantially increase hospital stay duration and fatality. Thus, MRSA infections are serious issues in this healthcare setting and should receive more attention from clinicians.

Amputation after failure or complication of total knee arthroplasty: prevalence, etiology and functional outcomes

Objective

Identify the etiology and incidence, as well to assess functional outcomes of patients, undergoing lower limb amputation after failure or complication of total knee arthroplasty. These patients were treated at the Center for Knee Surgery at the National Institute of Traumatology and Orthopedics (INTO), during the period of January 2001 to December 2010.

Methods

The patients were interviewed and their charts were retrospectively analyzed to evaluate their functional outcome.

Results

The incidence of amputation due to failure or complication of total knee arthroplasty was 0.41% in 2409 cases. Recurrent deep infection was the cause of amputation in 81% of cases, being Staphylococcus aureus and Pseudomonas aeruginosa the most frequent germs. Vascular complications and periprosthetic fracture associated to metaphyseal bone loss were also causes of amputation. In our study, 44% of amputees patients were using orthesis and 62.5% have had the ability to walk.

Conclusion

Incidence of 0.41%, being the main cause recurrent infection. The functional outcome is limited, and the fitting achieved in 44% of patients and only 62.5% are ambulatory.

The long-term results of a two-stage protocol for revision of an infected total knee replacement

We report the long-term results of the management of neglected chronically infected total knee replacements with a two-stage re-implantation protocol. In 18 of 34 patients (53%) a resistant organism was isolated. All cases were treated by the same surgical team in a specialist centre and had a mean follow-up of 12.1 years (10 to 14). They were evaluated clinically and radiologically using the Knee Society Score (KSS) and the American Knee Society Roentgenographic scoring system, respectively. One patient died after eight years from an unrelated cause and two were lost to follow-up. Three patients (8.8%) developed a recurrent infection for which further surgery was required. The infection was eradicated successfully in 31 patients (91.1%). There was one case of aseptic loosening after 13 years. We found a significant improvement in the KSS at final follow-up (p < 0.001).

MRSA colonisation and subsequent risk of infection despite effective eradication in orthopaedic elective surgery

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.

The role of pre-operative assessment and ringfencing of services in the control of methicillin resistant Staphlococcus aureus infection in orthopaedic patients

BACKGROUND

MRSA is a major economic and health issue internationally and as such is of particular importance in the appropriate management of orthopaedic patients. Bone, joint and implant infection can lead to unfavourable outcomes with a long protracted in hospital stay inevitable. The cost for the patient, the hospital and society are substantial.

MATERIALS AND METHODS

This study was a review of a prospectively maintained database from our unit over three time points from 2005 to 2007. At each time point a new infection control measure was implemented in an effort to reduce MRSA infections. Total rates of MRSA infection and colonisation in all orthopaedic patients were recorded, before and after separation of trauma and elective services, and after the introduction of a screening pre assessment clinic.

RESULTS

12259 orthopaedic patients were reviewed over the three years. The mean age of MRSA infected patients was 71. A higher proportion of female patients were infected than male patients. The mean length of stay for infected patients was 23.4 days. The rate of infection dropped from 0.49% in 2005 to 0.24%in 2007. After the introduction of these measures there was a substantial reduction in organ space and deep tissue infections.

CONCLUSION

The separation of emergency and elective orthopaedic services coupled with effective pre-operative screening has resulted in a significant reduction in MRSA infection despite an ever increasing prevalance.

Staphylococcus aureus Decolonization Protocol Decreases Surgical Site Infections for Total Joint Replacement

We investigated the effects of implementation of an institution-wide screening and decolonization protocol on the rates of deep surgical site infections (SSIs) in patients undergoing primary knee and hip arthroplasties. 2058 patients were enrolled in this study: 1644 patients in the treatment group and 414 in the control group. The treatment group attended preoperative admission testing (PAT) clinic where they were screened for MSSA and MRSA colonization. All patients were provided a 5-day course of nasal mupirocin and a single preoperative chlorhexidine shower. Additionally, patients colonized with MRSA received Vancomycin perioperative prophylaxis. The control group did not attend PAT nor receive mupirocin treatment and received either Ancef or Clindamycin for perioperative antibiotic prophylaxis. There were a total of 6 deep infections in the control group (1.45%) and 21 in the treatment group (1.28%); this represented a decrease of 13% (P = .809) in the treatment versus control group. This decrease represented a positive trend in favor of staphylococcus screening, decolonization with mupirocin, and perioperative Vancomycin for known MRSA carriers.

MRSA in a large German University Hospital: Male gender is a significant risk factor for MRSA acquisition

BACKGROUND

The continually rising number of hospital acquired infections and particularly MRSA (Methicillin-resistant Staphylococcus aureus) colonization poses a major challenge from both clinical and epidemiological perspectives. The assessment of risk factors is vital in determining the best prevention, diagnosis and treatment strategies.

MATERIALS AND METHODS

We analyzed 798 cases of MRSA in a large German University Hospital over a 7-year period. Data was collected retro- and prospectively including patient age, sex, type of ward and duration of inpatient stay. In addition we analyzed all cases on ICU with regards to cross infection and MRSA genotyping via DNA MicroArray Technology. The years 2004 to 2007 were analyzed with a specific focus on gender.

RESULTS

Male gender is significantly correlated with increased risk of MRSA acquisition (p<0.001), the predominant setting for MRSA is on ICU. 75% of the MRSA positive patients are over 50 years of age (average age 59.8 years). The inpatient time was 4.15 times higher in MRSA carriers compared with non-MRSA cases, however this was not significant. MRSA genotyping on ICU showed mainly the subtypes ST 5, ST 22, ST 228, however cross contamination with identical genotypes was only detected in a minority of cases (5 out of 22).

CONCLUSION

Unlike previous studies which show no or inconclusive evidence of gender as a risk factor, our data confirm that male gender is a significant risk factor for MRSA carrier status. Further research will be required to investigate the aetiology of these findings.

The impact of chronic obstructive pulmonary disease and obesity on length of stay and cost of spine surgery

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and obesity may be more common among spine surgery patients than in the general population and may affect hospital cost.

MATERIALS AND METHODS

We retrospectively studied the prevalence of COPD and obesity among 605 randomly selected spine surgery inpatients operated between 2005 and 2008, including lumbar microdiskectomy, anterior cervical decompression and fusion and lumbar decompression and fusion patients. The length of hospital stay and hospital charges for patients with and without COPD and obesity (body mass index [BMI]≥30 kg/m(2)) were compared.

RESULTS

Among 605 spine surgery patients, 9.6% had a history of COPD. There were no statistical difference in the prevalence of COPD between the three spine surgery groups. Obesity was common, with 47.4% of the patients having a BMI≥30 kg/m(2). There were no significant differences in obesity rates or BMI values between the three types of spine surgery patients. Obesity rates between patients with and without COPD were 62.1% vs. 45.9%, and were statistically different (P<0.05). Similarly, significant difference (P<0.01) in BMI values between COPD and non-COPD groups, 32.66±7.19 vs. 29.57±6.048 (mean ± std. deviation), was noted. There was significant difference (P<0.01) in cost between nonobese female patients without COPD and those with obesity and COPD in the anterior cervical decompression and fusion (ACDF) group. No association with increased hospital length of stay or cost was found in the other two types of spine surgery or in male ACDF patients.

CONCLUSION

COPD and obesity seem to additively increase the length of hospital stay and hospital charges in ACDF female patients, an important finding that requires further investigation.

Methicillin-resistant Staphylococcus aureus in orthopaedic trauma

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.

[Etiology of surgical site infections at the orthopaedic trauma units]

OBJECTIVES

The aim of the study was to analyze the epidemiological and microbiological analysis of surgical site infections in the orthopedic wards.

MATERIALS AND METHODS

A 6-month prospective cohort study was conducted at the major teaching hospital in Belgrade. Patient's basic demographic data and data about surgical site infections were collected. Bacteria cultured from the surgical site were also analyzed.

RESULTS

A total of 277 patients operated in the Institute of Orthopedics and trauma surgery, Clinical Center of Serbia. Sixty-three cases of SSI were detected, and the overall incidence rate was 22.7% (95% IP = 17.8-27.6). Fifty-three (84.1%) SSIs had microbiological confirmation and overall 82 bacterial strains were isolated. The most frequent isolated bacteria were Staphylococcus aureus, Acinetobacter sp, Klebsiella pp, Pseudomonas sp and Enterococcus sp. Nineteen (79.2%) strains of Staphylococcus aureus isolated from infected surgical sites were meticillin- resistant.

CONCLUSION

This study suggests that it is necessary to maintain continuous surveillance of surgical site infections. It is important to emphasize the need for implementation the measures of contact isolation in order to prevent the nosocomial transmission of resistant bacteria.