Infections after shoulder arthroplasty are correlated with higher anesthetic risk score: a case-control study in Brazil

ABSTRACT Purposes: Shoulder arthroplasty (SA) has been performed by many years for the treatment of several conditions, including osteoarthritis and proximal humeral fractures following trauma. Surgical site infection (SSI) following Shoulder arthroplasty remains a challenge, contributing to increased morbidity and costs. Identification of risk factors may help implementing adequate strategies to prevent infection. We aimed to identify pre- and intra-operative risk factors associated with deep infections after Shoulder arthroplasty. Methods: An unmatched case-control study was conducted to describe the prevalence, clinical and microbiological findings, and to evaluate patient and surgical risk factors for prosthetic shoulder infection (PSI), among 158 patients who underwent SA due to any reason, at a tertiary public university institution. Risk factors for PSI was assessed by uni- and multivariate analyses using multiple logistic regression. Results: 168 SA from 158 patients were analyzed, with an overall infection rate of 9.5% (16/168 cases). Subjects undergoing SA with American Society of Anesthesiologists (ASA) grade III or higher (odds ratio [OR] = 5.30, 95% confidence interval [CI] = 1.58-17.79, p < 0.013) and presenting local hematoma after surgery (odds ratio [OR] = 7.10, 95% confidence interval [CI] = 1.09-46.09, p = 0.04) had higher risk for PSI on univariate analysis. However, only ASA score grade III or higher remained significant on multivariate analysis (OR = 4.74, 95% CI = 1.33-16.92, p = 0.016). Gram-positive cocci and Gram-negative bacilli were equally isolated in 50% of cases; however, the most commonly detected bacterium was Pseudomonas aeruginosa (18.7%). Conclusion: This study provides evidence suggesting that patient-related known factors such as higher ASA score predisposes to shoulder arthroplasty-associated infection. Furthermore, unusual pathogens associated with PSI were identified.

Infecciones osteoarticulares en pacientes del Hospital del Instituto de Seguridad del Trabajador (IST) de Viña del Mar: periodo 2012-2013 / Osteoarticular infections in patients of the Hospital del Instituto de Seguridad del Trabajador in Viña del Mar (Chile): period 2012-2013

INTRODUCCIÓN: Las infecciones osteoarticulares son un desafío frecuente en la práctica traumatológica diaria. En Chile y en los distintos hospitales de la región de Valparaíso son escasos los trabajos con relación al tema, lo que es fundamental para optimizar el tratamiento, tanto quirúrgico como médico, de estas infecciones. OBJETIVOS: Describir las infecciones osteoarticulares del Hospital del IST de Viña del Mar durante el periodo 2012-2013. MATERIALES Y MÉTODO: Trabajo descriptivo retrospectivo de una serie de casos. Se revisaron las fichas clínicas de los pacientes que cursaron con alguna infección osteoarticular y se obtuvieron los datos demográficos y clínicos de cada paciente. RESULTADOS: Treinta pacientes fueron incluidos. Dieciséis (53,3%) fueron hombres con un promedio de edad de 38,5años. El 50% correspondieron a infecciones asociadas a la atención de salud. Las principales infecciones fueron asociadas a material de osteosíntesis. El agente más frecuente fue el Staphylococcus aureus meticilinosensible (SAMS). En la mayoría de los casos se realizó aseo quirúrgico, toma de cultivos e inicio de antibióticos con ceftriaxona más clindamicina. CONCLUSIONES: Las infecciones osteoarticulares ocurrieron principalmente en hombres jóvenes, fueron infecciones asociadas a material de osteosíntesis y producidas por SAMS.

INTRODUCTION: Osteoarticular infections are a common challenge in everyday trauma practice. In Chile, and in different hospitals in the region of Valparaiso, there are few studies on the issue, which is essential to optimise both surgical and medical treatment of these infections. OBJECTIVES: To describe the osteoarticular infections in the Hospital del Instituto de Seguridad del Trabajador (IST) of Viña del Mar during the 2012-2013 period. MATERIALS AND METHODS: A retrospective descriptive study was performed on a series of cases. A review was made of the medical records of patients with any osteoarticular infection. Demographic and clinical data were obtained from each patient. RESULTS: Of the total of 30 patients included, 16 (53.3%) were male with a mean age of 38.5 years. Half (50%) of the infections were associated with health care. Major infections were associated with osteosynthesis material. The most frequent agent was Methicillin Susceptible Staphylococcus aureus (MSSA). In most cases surgical cleanliness, taking of microbiological cultures, and antibiotic treatment with ceftriaxone plus clindamycin, was performed. CONCLUSIONS: Osteoarticular infections occurred mainly in young men, were infections associated to osteosynthesis material, and caused by MSSA.

Molecular & phenotypic characterization of Staphylococcus epidermidis in implant related infections.

Background & objectives: The discrimination between the Staphylococcus epidermidis colonizing the deep seated indwelling devices and those which are mere commensals has always been a challenge for the clinical microbiologist. This study was aimed to characterize the S. epidermidis isolates obtained from device related infection for their phenotypic and molecular markers of virulence and to see whether these markers can be used to differentiate the pathogenic S. epidermidis from the commensals. Methods: Fifty five S. epidermidis isolates from various device related infections such as endophthalmitis following intra-ocular lens (IOL) implantation, intravascular (IV) catheter related sepsis and orthopaedic implant infections, were studied for slime production, biotyping, antibiotic sensitivity; and mec A and ica positivity by the recommended procedures. Results: Twenty three (41.8%) isolates were multi-drug resistant, 26 (65.2%) were slime producers, 30 (54.5%) were adherent, 23 (41.8%) possessed the intercellular adhesin (ica) gene, and 28 (50.9%) harboured the mec A gene. Biotypes I and III were the commonest, most members of which were multi- drug resistant. Twenty two (73.3%) of the 30 adherent bacteria were slime producers as opposed to only 4 (16%) of the 25 non-adherent bacteria (P<0.001). A vast majority i.e. 21 (91.3%) of the 23 ica positive organisms were adherent to artificial surfaces in contrast to only 9 (28.1%) of the 32 non-ica positive organisms (P<0.001). Twenty (86.9%) of the 23 ica positive bacteria were slime producers, as opposed to only 6 (18.7%) of the 32 ica negative bacteria (P<0.001). Of the 23 multi-drug resistant isolates, 19 (82.6%) carried the mec A gene. Interpretation & conclusions: The present findings showed that ica AB and mec A were the two important virulence markers of S. epidermidis in implant infections and slime was responsible for the sessile mode of attachment on the devices.

Infecciones en prótesis articular / Prosthetic joint infections

Se realizó un estudio retrospectivo con el objetivo de conocer las principales características clínicas y epidemiológicas de las infecciones en prótesis articulares de cadera y rodilla. Para Ello se analizaron los registros disponibles desde 1993 identificando 19 episodios en 18 pacientes. La tasa de infección global fue de 2,84 porciento en 633 implantes y la de infecciones intrahospitalarias de 1,11 porciento. Un 70 porciento de los casos se presentó antes de los 18 meses de la instalación. La edad promedio de los pacientes fue de 70,5 años y 83 porciento era de sexo femenino. Tres pacientes tenían antecedentes de artritis reumatoidea y utilizaban corticosteroides. Los cultivos fueron positivos en 18 de los 19 episodios, predominando el género staphylococcus (49 porciento) y los bacilos gram negativos (37 porciento). En 12 de los 19 episodios se retiró la prótesis infectada (63 porciento). La sobrevida libre de recurrencias fue sifnificativamente superior en aquellos pacientes tratados quirúrgicamente durante el primer mes de hospitalización