No change in the distribution of types and antibiotic resistance in clinical Staphylococcus aureus isolates from orthopaedic patients during a period of 12 years.

Staphylococcus aureus (S. aureus) is the most common cause of bone and joint infections. However, limited information is available on the distribution of S. aureus geno- and phenotypes causing orthopaedic infections. The aim of this study was to identify the dominating types causing infections in orthopaedic patients, investigate if the characteristics of these types changed over time and examine if different types were more often associated with surgical site infection (SSI) than primary infection (non-SSI). All clinical S. aureus isolates collected from orthopaedic patients from 2000 through 2011 at Akershus University Hospital, Norway, were characterised by S. aureus protein A (spa) typing and tested for antibiotic resistance. A total of 548 patients with orthopaedic S. aureus infections were included, of which 326 (59 %) had SSI and 222 (41 %) had non-SSI. The median age was 62 years [range 2-97 years] and 54 % were male. Among the 242 unique spa types, t084 was the most common (7 %). Penicillin resistance was identified in 75 % of the isolates, whereas the resistances to the other antibiotics tested were <5 %. Three isolates (0.5 %) were resistant to methicillin. There was no significant difference in the distribution of geno- and phenotypes over time and there was no difference in types between SSI and non-SSI. In this large collection of S. aureus from orthopaedic patients, the S. aureus infections, regardless of origin, were heterogeneous, mainly resistant to penicillin, stable over time and consisted of similar types as previously found in both carrier and other patient populations.

Decreasing time trend in SSI incidence for orthopaedic procedures: surveillance matters!

BACKGROUND: Infection is the most common reason for early revision after hip and knee arthroplasty, and the revision rate is increasing. Surgical site infection (SSI) surveillance data are important to assess the true infection rate. There is little information regarding the potential time trend in SSI incidence following orthopaedic surgery. AIM: To evaluate whether a time trend exists in SSI incidence due to surveillance following orthopaedic surgery. METHODS: The SSI rates after hip and knee replacements and osteosynthesis of trochanteric femoral fractures and ankle fractures were recorded prospectively from May 1998 to October 2008 according to the criteria of the US Centers for Disease Control and Prevention. In total, 4177 procedures were analysed, 65.8% of which were performed on female patients. Linear regression was used to analyse trends in SSI rates. FINDINGS: SSI incidence decreased significantly from 7% in the first year to 3% in the last year; a 57% relative reduction. The duration of surgery was the only significant predictor for infection (P < 0.001) in a logistic regression model that also included age, American Society of Anesthesiologists' score and level of emergency. CONCLUSION: Surveillance following orthopaedic procedures showed a significant decrease in SSI incidence over the 11-year surveillance period. The causality between surveillance and SSI incidence is difficult to prove, but surveillance with feedback probably influences several procedures that affect the quality of health care, even if duration of surgery is the only significant predictor of this effect.

Molecular characterisation of methicillin-sensitive Staphylococcus aureus from deep surgical site infections in orthopaedic patients.

Staphylococcus aureus is a leading cause of surgical site infections (SSIs). The association between S. aureus genotypes and the severity of illness is, however, incompletely understood. The aim of the study was to genotype S. aureus isolates from deep SSI in orthopaedic patients to identify molecular markers associated with invasive S. aureus infections. DNA microarray analysis was performed on S. aureus isolates collected from 60 patients with deep SSI following major orthopaedic surgery, while 57 isolates from nasal carriers served as controls. Genes associated with antibiotic resistance, adhesion, immune evasion, tissue invasion and toxin production were detected. The bone sialoprotein-binding protein gene (bbp) was more frequent in isolates from SSI patients compared to nasal carriers (95.0% vs. 82.5%), suggesting a role in invasive disease. No major differences in other molecular virulence markers could be distinguished among isolates from the two clinical groups, suggesting that any S. aureus strain may cause invasive infection. Our study reveals important genotypic information on isolates obtained from deep SSI following orthopaedic procedures.

Use of rifampicin and ciprofloxacin combination therapy after surgical debridement in the treatment of early manifestation prosthetic joint infections.

Prosthetic joint infections are difficult to eradicate, and antibiotic and surgical treatment strategies lack standardisation. The present study followed 29 patients (median age 72 years, median American Society of Anesthesia score of two) with early prosthetic joint infections. Treatment consisted of device retention, surgical debridement and therapy with rifampicin and ciprofloxacin for 3 months. This treatment regimen failed in five patients during the study, with a median observation period of 674 days. The results of this study confirm the findings of the only previous study on device retention with antibiotic treatment.

Breech delivery. An obstetrical analysis.

Fivehundred and eighty consecutive breech births during the period 1972-79 were analvsed for factors associated with neonatal mortality. The overall neonatal mortality in breech deliveries in this series of cases was 4.1%. Multivariate analyses (logistic regression) selected only 4 of 56 variables tested as significant (p less than 0.05) risk factors for neonatal death. The overall most important risk factor was low birth weight (p less than 0.0001). In addition, diabetes in the mother, malformations, and Apgar score 5 min less than 7 increased the risk of neonatal death. Cesarean section was carried out in 8.1% during the period 1972-75, but increased to 32.6% from 1976-79 without any reduction in neonatal mortality. Neonatal mortality figures were not significantly improved for infant delivered by cesarean section compared with those born vaginally.