Prosthetic joint infection caused by Mediterraneibacter gnavus following total knee arthroplasty, challenges in anaerobic bacteria identification.

BACKGROUND: Mediterraneibacter gnavus is a Gram positive, non-sporulated, obligate anaerobe diplococci. It was first described in 1974 by Moore et al. (under the name Ruminococcus gnavus) from faeces and contents of the gastrointestinal tract of humans. It is a relatively common member of the human gut microbiota, nevertheless its role as a pathogenic bacterium has not been completely elucidated yet and it seems to depend on numerous factors, including those of the host. Here we present a case of prosthetic joint infection following total knee arthroplasty by M. gnavus. CASE PRESENTATION: A 74 years old patient was admitted to the emergency department presenting with acute onset of left knee pain and swelling 20 days after total left knee arthroplasty. Follow-up revealed erythema and oedema without signs of fluctuation or purulent discharge from the surgical wound and elevated inflammatory reactants. Synovial fluid was taken for bacterial culture and antibiotic treatment with ceftazidime and daptomycin was established. Examination of the synovial fluid revealed abundant polymorphonuclear leucocytes, without visualizing bacteria. After four days of incubation, anaerobic culture exhibit growth of small, grey, umbilicated colonies in pure culture on Schaedler agar. The microorganism was identified as R. gnavus by MALDI-TOF (Bruker Daltonics) and M. gnavus by 16S ribosomal bacterial sequencing. The isolated showed susceptibility to the most commonly used anaerobicidal antibiotics except for clindamycin. Surgical treatment and infection source control included DAIR (debridement, antibiotics, and implant retention) and vacuum assisted therapy. The patient was discharged after six weeks with a 3-month course of oral amoxicillin as consolidation therapy. Subsequent follow-up revealed adequate wound healing with no signs of infection. CONCLUSIONS: Mediterraneibacter gnavus have been reported as the causal microorganism in a range of human infections, nevertheless its identification remains challenging. Infection of prosthetic joints by anaerobic microorganisms is uncommon and is not considered in its empirical antibiotic treatment, thus, correct and swift identification of anaerobic bacteria in these cases is paramount.

Characterization of wound infections among patients injured during the Ruso-Ukrainian war in a Role 4 hospital.

INTRODUCTION: The management of infections in war wounds is a problem aggravated by the presence of multiresistant bacteria and requires a combined approach with surgery. Literature has identified the risks and patterns of antibiotic resistance in previous armed conflicts, but the Russian-Ukrainian conflict has required the study of specific bacterial resistance patterns. METHODS: We included war-injured patients from the Russian-Ukrainian conflict transferred for treatment to the General Defense Hospital of Zaragoza from May 2022 to October 2023. Epidemiological data, factors related to the injury, presence of infection and microbiological results were collected; These data were subsequently analyzed statistically. RESULTS: Fifty-three patients were included in the study, with a mean age of 35.6 years; 83% were injured by an explosive mechanism and all received antibiotic therapy prior to transfer. Seventeen patients had skin, soft tissue or joint infection. Correlation was demonstrated with the presence of bone lesion (p 0.03), skin coverage defect (p 0.000) and presence of foreign bodies (p 0.006). Nine patients had monomicrobial cultures, and the most frequently isolated microorganisms were Gram negative bacilli (GNB) and Staphylococcus aureus. Virtually all GNB presented some resistance mechanism. CONCLUSION: Our work shows the correlation of war wound infection with the presence of foreign bodies and affected tissues. Likewise, the presence of polymicrobial wounds is emphasized, with a predominance of GNB and multidrug-resistant S. aureus.

Linezolid for therapy of Staphylococcus aureus meningitis: a cohort study of 26 patients.

BACKGROUND: Linezolid has good penetration to the meninges and could be an alternative for treatment of Staphylococcus aureus meningitis. We assessed the efficacy and safety of linezolid therapy for this infection. METHODS: Retrospective multicenter cohort study of 26 adults treated with linezolid, derived from a cohort of 350 cases of S. aureus meningitis diagnosed at 11 university hospitals in Spain (1981-2015). RESULTS: There were 15 males (58%) and mean age was 47.3 years. Meningitis was postoperative in 21 (81%) patients. The infection was nosocomial in 23 (88%) cases, and caused by methicillin-resistant S. aureus in 15 cases and methicillin-susceptible S. aureus in 11. Linezolid was given as empirical therapy in 10 cases, as directed therapy in 10, and due to failure of vancomycin in 6. Monotherapy was given to 16 (62%) patients. Median duration of linezolid therapy was 17 days (IQR 12-22 days) with a daily dose of 1,200 mg in all cases. The clinical response rate to linezolid was 69% (18/26) and microbiological response was observed in 14 of 15 cases evaluated (93%). Overall 30-day mortality was 23% and was directly associated with infection in most cases. When compared with the patients of the cohort, no significant difference in mortality was observed between patients receiving linezolid or vancomycin for therapy of methicillin-resistant S. aureus meningitis (9% vs. 20%; p = .16) nor between patients receiving linezolid or cloxacillin for therapy of methicillin-susceptible S. aureus meningitis (20% vs 14%; p = .68). Adverse events appeared in 14% (3/22) of patients, but linezolid was discontinued in only one patient. CONCLUSIONS: Linezolid appears to be effective and safe for therapy of S. aureus meningitis. Our findings showed that linezolid may be considered an adequate alternative to other antimicrobials in meningitis caused by S. aureus.

[Autochthonous amebic liver abscess in Spain: an emerging disease? Case report and description of a PCR-based diagnostic test]. / Absceso hepático amebiano autóctono en España: una enfermedad emergente? Descripción de 2 nuevos casos clínicos y de una técnica diagnóstica basada en la reacción en cadena de la polimerasa.

INTRODUCTION: In Spain an increase in cases of amebiasis has been detected in patients with no history of traveling to, or immigration from, endemic areas. MATERIAL AND METHODS: This study describes two new cases of amebic hepatic abscess due to native protozoa and reviews 21 more cases of amebic hepatic abscess reported in Spanish patients who had never left the Iberian Peninsula. In addition, a new PCR-based technique for diagnosing Entamoeba histolytica is described. RESULTS: Twenty cases (87%) occurred in men. The age range of the affected patients was 26 to 77 years. Two of the 3 women with extraintestinal amebiasis were HIV-positive. There was no history of exposure to the parasite in 17 cases. In the remaining 6 cases, direct contact with patients affected with amebiasis or with individuals or foods from endemic areas was recorded. CONCLUSION: Entamoeba histolytica infection is becoming an emerging disease in our country. Amebiasis should be included in the differential diagnosis of consistent clinical entities even when there is no background of traveling or immigration. New molecular diagnostic tools can help to characterize this infection and should be considered reference techniques in combination with serological methods.

Comparing Two Automated Techniques for the Primary Screening-Out of Urine Culture.

Urinary tract infection is the most common human infection with a high morbidity. In primary care and hospital services, conventional urine culture is a key part of infection diagnosis but results take at least 24 h. Therefore, a rapid and reliable screening method is still needed to discard negative samples as quickly as possible and to reduce the laboratory workload. In this aspect, this study aims to compare the diagnostic performance between Sysmex UF-1000i and FUS200 systems in comparison to urine culture as the gold standard. From March to June 2016, 1,220 urine samples collected at the clinical microbiology laboratory of the "Miguel Servet" hospital were studied in parallel with both analysers, and some technical features were evaluated to select the ideal equipment. The most balanced cut-off values taking into account bacteria or leukocyte counts were 138 bacteria/µL or 119.8 leukocyte/µL for the UF-1000i (95.3% SE and 70.4% SP), and 5.7 bacteria/µL or 4.3 leukocyte/µL for the FUS200 (95.8% SE and 44.4% SP). The reduction of cultured plates was 37.4% with the FUS200 and 58.3% with the UF-1000i. This study shows that both techniques improve the workflow in the laboratory, but the UF-1000i has the highest specificity at any sensitivity and the FUS200 needs a shorter processing time.

Absceso hepático amebiano autóctono en España: ¿una enfermedad emergente? Descripción de 2 nuevos casos clínicos y de una técnica diagnóstica basada en la reacción en cadena de la polimerasa / Autochthonous amebic liver abscess in Spain: An emerging disease? Case report and description of a PCR-based diagnostic test

Introducción: En España se está detectando un aumento de la amebiasis en personas sin antecedentes de viajes o que no proceden de zonas endémicas.Material y métodos: En este trabajo se presentan 2 nuevos casos de absceso hepático amebiano (AHA) autóctono y se revisan otros 21 casos de AHA descritos con anterioridad en España en pacientes que nunca habían salido de la Península Ibérica. Además, se describe una técnica molecular de reacción en cadena de la polimerasa para el diagnóstico de Entamoeba histolytica.Resultados: Veinte casos (87%) se dieron en varones. La edad de los enfermos varió entre 26 y 77 años. Dos de las 3 mujeres con amebiasis extraintestinal tenían el virus de la inmunodeficiencia humana. En 17 individuos no se encontraron datos de exposición a los que se les pudiera atribuir el contagio de la infección. En los 6 restantes se registraron antecedentes de contacto directo con enfermos de amebiasis o con personas o alimentos sospechosos procedentes de zonas endémicas.Discusión: La infección por E. histolytica se está convirtiendo en una infección emergente en el medio. La amebiasis debería considerarse en el diagnóstico diferencial de entidades clínicas compatibles, incluso en ausencia de antecedentes epidemiológicos de viajes o inmigración. Las nuevas técnicas diagnósticas moleculares pueden ayudar a caracterizar esta infección y deben considerarse métodos de referencia junto con las pruebas serológicas (AU)

Introduction: In Spain an increase in cases of amebiasis has been detected in patients with no history of traveling to, or immigration from, endemic areas.Material and Methods: This study describes two new cases of amebic hepatic abscess due to native protozoa and reviews 21 more cases of amebic hepatic abscess reported in Spanish patients who had never left the Iberian Peninsula. In addition, a new PCR-based technique for diagnosing Entamoeba histolytica is described.Results: Twenty cases (87%) occurred in men. The age range of the affected patients was 26 to 77 years. Two of the 3 women with extraintestinal amebiasis were HIV-positive. There was no history of exposure to the parasite in 17 cases. In the remaining 6 cases, direct contact with patients affected with amebiasis or with individuals or foods from endemic areas was recorded.Conclusion: Entamoeba histolytica infection is becoming an emerging disease in our country. Amebiasis should be included in the differential diagnosis of consistent clinical entities even when there is no background of traveling or immigration. New molecular diagnostic tools can help to characterize this infection and should be considered reference techniques in combination with serological methods (AU)

Panoftalmitis tras el uso de cocaína tópica en paciente VIH+ / Panophthalmitis following topical cocaine use in an HIV+ patient

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