Cutibacterium spp. isolated from orthopaedic implant-associated infection: A not-so-slowly growing organism.

INTRODUCTION: It has been reported that microbiological diagnosis of Cutibacterium spp. infection requires a prolonged incubation time (up to 14 days). We present our experience with regard to incubation time for detection of Cutibacterium spp. in orthopaedic samples over a 10-year period. METHODS: One hundred and nineteen samples were included in this retrospective study. Fifty-three were implants (having previously undergone sonication), 64 were periprosthetic tissue biopsies and two were synovial fluids. Atkins's criteria were used for interpreting the isolates. Quantification and number of days until a culture became positive for Cutibacterium spp. were evaluated. RESULTS: The median number of days to detection of a clinically significant isolate and a contaminant was 4 days. No clinically significant isolates grew after day eight. CONCLUSION: Most clinically significant isolates of Cutibacterium spp. are detected in the first 7 days of incubation, although a recommendation of prolonged incubation (up to 14 days) appears to be necessary for detecting other organisms.

Cutibacterium spp. isolated from orthopaedic implant-associated infection: A not-so-slowly growing organism / Cutibacterium spp. aislados de infecciones ortopédicas asociadas a implantes: Un microorganismo de crecimiento no tan lento

Introduction: It has been reported that microbiological diagnosis of Cutibacterium spp. infection requires a prolonged incubation time (up to 14 days). We present our experience with regard to incubation time for detection of Cutibacterium spp. in orthopaedic samples over a 10-year period. Methods: One hundred and nineteen samples were included in this retrospective study. Fifty-three were implants (having previously undergone sonication), 64 were periprosthetic tissue biopsies and two were synovial fluids. Atkins's criteria were used for interpreting the isolates. Quantification and number of days until a culture became positive for Cutibacterium spp. were evaluated. Results: The median number of days to detection of a clinically significant isolate and a contaminant was 4 days. No clinically significant isolates grew after day eight. Conclusion: Most clinically significant isolates of Cutibacterium spp. are detected in the first 7 days of incubation, although a recommendation of prolonged incubation (up to 14 days) appears to be necessary for detecting other organisms.(AU)

Introducción: Se ha reportado que el diagnóstico microbiológico de las infecciones por Cutibacterium spp. requiere un tiempo de incubación prolongado (hasta 14 días). Presentamos nuestra experiencia al respecto en muestras ortopédicas durante un período de 10 años. Métodos: Se incluyeron en este estudio retrospectivo 119 muestras de las que 53 fueron implantes (previa sonicación), 64 biopsias de tejido periprotésico y dos líquidos sinoviales. Para la interpretación se siguieron los criterios de Atkins. Se evaluó la cuantificación y el número de días hasta que el cultivo fue positivo para Cutibacterium spp. Resultados: La mediana del número de días para detectar un aislado clínicamente significativo y un contaminante fue de cuatro días. Ningún aislado clínicamente relevante creció después del día ocho. Conclusión: La mayoría de aislados clínicamente significativos de Cutibacterium spp. se detectan durante los siete primeros días de incubación, sin embargo, parece necesaria una incubación de hasta 14 días para la detección de otros microorganismos.(AU)

Executive summary of management of prosthetic joint infections. Clinical practice guidelines by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC).

The incidence of prosthetic joint infection (PJI) is expected to increase in the coming years. PJI has serious consequences for patients, and high costs for the health system. The complexity of these infections makes it necessary to organize the vast quantity of information published in the last several years. The indications for the choice of a given surgical strategy and the corresponding antimicrobial therapy are specifically reviewed. The authors selected clinically relevant questions and then reviewed the available literature in order to give recommendations according to a pre-determined level of scientific evidence. The more controversial aspects were debated, and the final composition was agreed at an ad hoc meeting. Before its final publication, the manuscript was made available online in order that all SEIMC members were able to read it and make comments and suggestions.

Evaluation of a commercial multiplex PCR (Unyvero i60®) designed for the diagnosis of bone and joint infections using prosthetic-joint sonication.

BACKGROUND: The development of sonication protocols over the last few years has improved the sensitivity of conventional cultures for the diagnosis of prosthetic-joint infection (PJI). However, the development of a new, specifically designed kit for the molecular diagnosis of PJI could provide a major improvement in this field. METHODS: Prostheses retrieved from patients who underwent implant removal from May 2014 to May 2015 were sent for culture, and processed according to a previously defined protocol that included sonication. Furthermore, 180 microlitres of sonication fluid were used to carry out the multiplex PCR test (Unyvero i60 system®). A comparison of the sensitivity, specificity, positive (PPV) and negative (NPV) predictive value, was performed. The study was approved by the Clinical Research Ethics Committee. RESULTS: The analysis included 88 prostheses from 68 patients (1.29 prostheses/patient). The type of prostheses studied were knee (n=55), total hip (n=26), partial hip (n=5), and shoulder (n=2). Twenty-nine patients were diagnosed with a PJI (15 delayed, 12 acute, and 2 haematogenous infections). In 24 cases, the result of the PCR was positive, all but 1 corresponding to patients with clinical criteria of PJI. Nine resistance mechanisms were detected from 5 samples. The Unyvero i60 system® showed slightly better results than traditional culture in terms of specificity and PPV. CONCLUSIONS: The Unyvero i60 system® may play a role in rapid diagnosis of PJI, due to its high specificity and PPV. However, despite these results, cultures have to be performed to detect organisms not detected by the system.

Protocolo combinado de 99mTc-Ciprofloxacina y 99mTc-MDP en el diagnóstico de osteomielitis y prótesis articular infectada / 99mTc-ciprofloxacin/99mTc-MDP combined protocol in the diagnosis of osteomyelitis and infected joint prosthesis

Introducción. El centellograma óseo con 99mTc-MDP es una técnica útil en el diagnóstico de osteomielitis, sin embargo, presenta especificidad limitada en presencia de patología ósea previa (osteomielitis complicada). La 99mTc-ciprofloxacina es uno de los radiofármacos más difundidos para la detección de infecciones óseas, aunque persisten controversias sobre su rendimiento diagnóstico. Objetivo. Determinar el valor clínico del protocolo combinado de centellograma con 99mTc-ciprofloxacina y 99mTc-MDP en el diagnóstico de osteomielitis complicada y prótesis articular infectada. Materiales y métodos 37 pacientes con sospecha clínica de osteomielitis complicada o prótesis infectada fueron estudiados mediante centellograma con 99mTc-ciprofloxacina y 99mTc-MDP. 26/37 pacientes presentaban fractura previa, 7 prótesis de rodilla y 4 prótesis de cadera. En todos ellos se realizó seguimiento clínico y bacteriológico. Resultados. El método presentó sensibilidad de 94 por ciento, especificidad de 79 por ciento, valor predictivo positivo de 81 por ciento y valor predictivo negativo de 94 por ciento, con una exactitud de 86 por ciento. Conclusiones. El protocolo combinado de 99mTc-ciprofloxacina y 99mTc-MDP presenta elevado rendimiento para el diagnóstico de osteomielitis complicada y prótesis articular infectada.

Introduction. Bone scintigraphy with 99mTc-MDP is a useful technique in the diagnosis of osteomyelitis, however, has limited specificity in the presence of previous bone pathology (complicated osteomyelitis). 99mTc-ciprofloxacin is one of the most widely used radiotracers for the detection of bone infection, although controversies persist on its diagnostic performance. Objective To determine the clinical value of 99mTc-ciprofloxacin/99mTc-MDP combined protocol in the diagnosis of complicated osteomyelitis and infected joint prosthesis. Materials and methods 37 patients with clinically suspected complicated osteomyelitis or infected prosthesis were studied with 99mTc-ciprofloxacin and 99mTc-MDP scintigraphy. 26/37 patients had previous fractures, 7 had knee replacements and 4 had hip replacements. All of the patients underwent clinical and bacteriological follow-up. Results. The method presented sensitivity of 94 percent, 79 percent specificity, 81 percent positive predictive value and 94 percent negative predictive value, with an accuracy of 86 percent. Conclusions. The combined protocol using 99mTc-ciprofloxacin/99mTc-MDP showed high diagnostic performance in complicated osteomyelitis and infected joint prosthesis.