Bacterial Skin Dysbiosis in Darier Disease.

INTRODUCTION: Darier disease is a rare inherited disease with dominant skin manifestations including keratotic papules and plaques on sebaceous and flexural areas. Secondary infection of skin lesions is common, and Staphylococcus aureus commonly colonizes these lesions. The aim of the study was to characterize the bacterial microbiome of cutaneous Darier lesions compared to normal-looking skin and disease severity. METHODS: All patients with a history of Darier followed up at Emek Medical Center were invited to participate in the study. Patients that did not use antibiotics in the past month and signed informed consent had four skin sites sampled with swabs: scalp, chest, axilla, and palm. All samples were analyzed for bacterial microbiome using 16S rDNA sequencing. RESULTS: Two hundred and eighty microbiome samples obtained from lesional and non-lesional skin of the scalp, chest, axilla, and palm of 42 Darier patients were included in the analysis. The most abundant bacterial genera across all skin sites were Propionibacterium, Corynebacterium, Paracoccus, Micrococcus, and Anaerococcus. Scalp and chest lesions featured a distinct microbiome configuration that was mainly driven by an overabundance of Staphylococci species. Patients with more severe disease exhibited microbiome alterations in the chest, axilla, and palm compared with patients with only mild disease, driven by Peptoniphilus and Moryella genera in scalp and palmar lesions, respectively. CONCLUSION: Staphylococci were significantly associated with Darier lesions and drove Darier-associated dysbiosis. Severity of the disease was associated with two other bacterial genera. Whether these associations also hold a causative role and may serve as a therapeutic target remains to be determined and requires further investigation.

Differential flora in the microenvironment of lung tumor and paired adjacent normal tissues.

Recent evidence demonstrates the existence of diversified microbiota in the lung. However, the effect of lung carcinogenesis on the flora in lung microenvironment has yet not been well investigated. In this study, we surveyed the microbial composition and diversity in lung tumor and paired adjacent normal tissues obtained from 55 lung cancer patients to test whether any specific tumor-associated microbial features in lung microenvironment can be identified. Compared with non-malignant adjacent tissues, the tumor samples showed significantly lower community richness (α diversity), but no significant difference in overall microbiome dissimilarity (ß diversity). Strong intrasubject correlations were observed between tumor sample and its paired non-malignant adjacent tissues. In addition, correlation network analysis found more significant taxa-taxa correlations (adjusted q-value < 0.05) in tumor microenvironment than non-malignant adjacent tissues. At taxa level, we found Propionibacterium genus were significantly reduced in tumor tissues compared with non-malignant adjacent tissues. In summary, the microbiota in tumor tissues showed the lower richness, higher taxa-taxa interaction, and reduction of potential pro-inflammatory microbial genera compared with non-malignant tissues, suggesting the potential link between the tumor microbiota and the altered tumor microenvironment for the further investigation.

Enterobacter cloacae Periprosthetic Joint Infection After Bariatric Surgical Anastomotic Leak.

Four weeks after a bilateral total knee arthroplasty (TKA), an immunocompetent, 61-year-old, Caucasian man presented with a periprosthetic joint infection (PJI) of the left knee by Enterobacter cloacae (an enteric bacteria). The most likely source of his infection was due to an anastomotic leak after a bariatric surgery done 6 months before TKA. There is a growing focus on stratifying the risk of PJI after TKA. Hematogenous seeding of enteric bacteria leading to PJI is an unexplored risk that will become more prevalent as bariatric procedures before TKA continue to increase in frequency. We present a patient who demonstrates this PJI risk with a rare microbe (E cloacae).

Targeting the Cutaneous Microbiota in Atopic Dermatitis by Coal Tar via AHR-Dependent Induction of Antimicrobial Peptides.

Skin colonization by Staphylococcus aureus and its relative abundance is associated with atopic dermatitis (AD) disease severity and treatment response. Low levels of antimicrobial peptides in AD skin may be related to the microbial dysbiosis. Therapeutic targeting of the skin microbiome and antimicrobial peptide expression can, therefore, restore skin homeostasis and combat AD. In this study, we analyzed the cutaneous microbiome composition in 7 patients with AD and 10 healthy volunteers upon topical coal tar or vehicle treatment. We implemented and validated a Staphylococcus-specific single-locus sequence typing approach combined with classic 16S ribosomal RNA marker gene sequencing to study the bacterial composition. During coal tar treatment, Staphylococcus abundance decreased, and Propionibacterium abundance increased, suggesting a shift of the microbiota composition toward that of healthy controls. We, furthermore, identified a hitherto unknown therapeutic mode of action of coal tar, namely the induction of keratinocyte-derived antimicrobial peptides via activation of the aryl hydrocarbon receptor. Restoring antimicrobial peptide levels in AD skin via aryl hydrocarbon receptor-dependent transcription regulation can be beneficial by creating a (anti)microbial milieu that is less prone to infection and inflammation. This underscores the importance of coal tar in the therapeutic aryl hydrocarbon receptor armamentarium and highlights the aryl hydrocarbon receptor as a target for drug development.

Seborrheic dermatitis-Looking beyond Malassezia.

Seborrhoeic Dermatitis (SD) is a very common chronic and/or relapsing inflammatory skin disorder whose pathophysiology remains poorly understood. Yeast of the genus Malassezia has long been regarded as a main predisposing factor, even though causal relationship has not been firmly established. Additional predisposing factors have been described, including sebaceous activity, host immunity (especially HIV infection), epidermal barrier integrity, skin microbiota, endocrine and neurologic factors, and environmental influences. Genetic studies in humans and mouse models-with particularly interesting insights from examining the Mpzl3 knockout mice and their SD-like skin phenotype, and patients carrying a ZNF750 mutation-highlight defects in host immunity, epidermal barrier and sebaceous activity. After synthesizing key evidence from the literature, we propose that intrinsic host factors, such as changes in the amount or composition of sebum and/or defective epidermal barrier, rather than Malassezia, may form the basis of SD pathobiology. We argue that these intrinsic changes provide favourable conditions for the commensal Malassezia to over-colonize and elicit host inflammatory response. Aberrant host immune activity or failure to clear skin microbes may bypass the initial epidermal or sebaceous abnormalities. We delineate specific future clinical investigations, complemented by studies in suitable SD animal models, that dissect the roles of different epidermal compartments and immune components as well as their crosstalk and interactions with the skin microbiota during the process of SD. This research perspective beyond the conventional Malassezia-centric view of SD pathogenesis is expected to enable the development of better therapeutic interventions for the management of recurrent SD.

C-reactive protein misdiagnoses delayed postoperative spinal implant infections in patients with low-virulent microorganisms.

PURPOSE: C-reactive protein (CRP) has been shown to be a powerful parameter for detecting acute postoperative spinal implant infections (PSII) with a high sensitivity and specificity. However, little data are available on the performance of CRP in the diagnosis of delayed PSII. The aim of the current study was therefore to establish cutoff values for diagnosing delayed infection based on serum CRP. METHODS: All patients who underwent a revision surgery after instrumented spinal fusion from January 2013 through January 2016 were included. Demographic data, laboratory values, type of infection (including microbiological and pathological results), comorbidities and clinical manifestation were collected. The European Bone and Joint Infection Society criteria, proposed to diagnose periprosthetic joint infection, were used to diagnose PSII. RESULTS: A total of 257 patients were included. PSII was diagnosed in 61 patients, representing 24% of the study cohort. There was a significant difference in serum CRP levels between septic and aseptic cohorts (19.3 vs. 4.8 mg/l, p < 0.001). However, 26 patients (43%) from the PSII group had a normal (< 5 mg/l) serum CRP level prior to revision surgery. According to the ROC curve, a serum CRP threshold of 4.05 mg/l had a sensitivity of 64% and specificity of 68%. The most common isolated microorganism was Propionibacterium spp. followed by coagulase-negative staphylococci. CONCLUSION: Serum CRP showed low sensitivity and specificity for diagnosis of delayed PSII, even after applying cutoffs optimized by using receiver operating curve analysis, because of the high incidence of low-virulent pathogens. These slides can be retrieved under Electronic Supplementary Material.

Pott's puffy tumor by Actinomyces after minor head trauma. / Pott's puffy tumor por Actinomyces tras trauma craneal leve.

Pott's puffy tumour (PPT) is a rare entity that involves scalp swelling associated with subperiosteal abscess and cranial osteomyelitis, occasionally accompanied by intracranial infection. It is usually affiliated with frontal sinusitis, which is a typical but infrequent complication. On the contrary, Osteomyelitis by Actinomyces is rare and usually occurs at the mandibular level, with very few cases of cranial osteomyelitis caused by this bacterial specie, especially after traumatic brain injury. We report an exceptionally unusual case of a PPT frontal tumor after blunt trauma (closed head injury), with an intracranial lesion whereby Actinomyces was isolated after surgery, as a co-participant of the mentioned infection besides Fusobacterium and Propionibacterium.

A Natural History of Actinic Keratosis and Cutaneous Squamous Cell Carcinoma Microbiomes.

Cutaneous squamous cell carcinoma (SCC) is the second-most-common cancer in Australia. The majority of SCCs progress from premalignant actinic keratosis (AK) lesions that form on chronically sun-exposed skin. The role of skin microbiota in this progression is not well understood; therefore, we performed a longitudinal microbiome analysis of AKs and SCCs using a cohort of 13 SCC-prone immunocompetent men. The majority of variability in microbial profiles was attributable to subject, followed by time and lesion type. Propionibacterium and Malassezia organisms were relatively more abundant in nonlesional photodamaged skin than in AKs and SCCs. Staphylococcus was most commonly associated with lesional skin, in particular, sequences most closely related to Staphylococcus aureus Of 11 S. aureus-like operational taxonomic units (OTUs), six were significantly associated with SCC lesions across seven subjects, suggesting their specific involvement with AK-to-SCC progression. If a causative link exists between certain S. aureus-like OTUs and SCC etiology, therapeutic approaches specifically targeting these bacteria could be used to reduce SCC.IMPORTANCE Actinic keratosis (AK) and cutaneous squamous cell carcinoma (SCC) are two of the most common dermatologic conditions in Western countries and cause substantial morbidity worldwide. The role of human papillomaviruses under these conditions has been well studied yet remains inconclusive. One PCR-based study has investigated bacteria in the etiology of these conditions; however, no study has investigated the microbiomes of AK and SCC more broadly. We longitudinally profiled the microbiomes of 112 AK lesions, profiled cross sections of 32 spontaneously arising SCC lesions, and compared these to matching nonlesional photodamaged control skin sites. We identified commonly occurring strains of Propionibacterium and Malassezia at higher relative abundances on nonlesional skin than in AK and SCC lesions, and strains of Staphylococcus aureus were relatively more abundant in lesional than nonlesional skin. These findings may aid in the prevention of SCC.

Characterisation of the nasal microbiota in granulomatosis with polyangiitis.

OBJECTIVES: Prior studies have suggested a potential link between nasal microbes and granulomatosis with polyangiitis (GPA; Wegener's), but these studies relied on culture-dependent methods. This study comprehensively examined the entire community of nasal microbiota (bacteria and fungi) in participants with GPA compared with healthy controls using deep sequencing methods. METHODS: 16S rRNA and internal transcribed spacer gene sequencing were performed on nasal microbial DNA isolated from nasal swabs of 60 participants with GPA and 41 healthy controls. Alpha and beta diversity were assessed as well as the relative abundance of the most abundant bacterial and fungal taxa. The effects of covariates including disease activity and immunosuppressive therapies on microbial composition were evaluated. RESULTS: Compared with controls, participants with GPA had a significantly different microbial composition (weighted UniFrac p=0.04) and lower relative abundance of Propionibacterium acnes and Staphylococcus epidermidis (for both, false discovery rate-corrected p=0.02). Disease activity in GPA was associated with a lower abundance of fungal order Malasseziales compared with participants with GPA in remission (p=0.04) and controls (p=0.01). Use of non-glucocorticoid immunosuppressive therapy was associated with 'healthy' nasal microbiota while participants with GPA who were off immunosuppressive therapy had more dysbiosis (weighted UniFrac p=0.01). No difference in the relative abundance of Staphylococcus aureus was observed between GPA and controls. CONCLUSIONS: GPA is associated with an altered nasal microbial composition, at both the bacterial and fungal levels. Use of immunosuppressive therapies and disease remission are associated with healthy microbial communities.

Preoperative skin cultures are predictive of Propionibacterium load in deep cultures obtained at revision shoulder arthroplasty.

BACKGROUND: Propionibacterium-specific cultures are commonly positive in revised shoulders without obvious signs of infection. To help identify patients at risk for these "stealth" presentations of positive Propionibacterium cultures, we assessed the value of a preoperative skin culture in predicting the results of deep cultures obtained at the time of revision shoulder arthroplasty in patients without clinical evidence of infection. METHODS: The study enrolled 60 patients undergoing revision for a prior shoulder arthroplasty without clinical evidence of infection. A preoperative culture of the skin surface was taken before skin preparation. At surgery, multiple (mean 5.9 ± standard deviation 1.6) deep tissue and explant cultures were harvested from the shoulder. Each culture was semiquantitatively reported as the specimen Propionibacterium value (SpPV). All SpPVs from the deep specimens from each patient were summed as the total shoulder Propionibacterium score (ShPS). The averaged ShPS was the total ShPS divided by the number of deep specimens harvested. RESULTS: A multivariate analysis demonstrated that the preoperative skin SpPV was predictive of the Propionibacterium load in the revised shoulders as indicated by the total ShPS (P = .004) and averaged ShPS (P = .003). CONCLUSIONS: In this series of patients, a preoperative culture of the unprepared skin was strongly predictive of the Propionibacterium load in revised shoulder arthroplasties without clinical evidence of infection. This result suggests that the results of skin cultures taken before revision surgery may help inform operative management with respect to the need for prosthesis exchange and extended postoperative antibiotic treatment.

What can we learn from sonication results of breast implants?

BACKGROUND: Different research groups have identified microorganisms on breast implants by sonication with significant correlation to the rate of capsular contracture. This substantiated the hypothesis of an infectious etiology of capsular contracture. However, no clinical consequence has been drawn from these results yet. Aim of this study was to review sonication results from breast implants and to evaluate the current preoperative antibiotic regime for breast-implant surgery. METHODS: We compared breast implant sonication culture results from published reports and our own database. Current perioperative antibiotic recommendations were compared with the susceptibility profile of the found organisms. RESULTS: We found Coagulase-negative staphylococci and Propionibacteria to be the main group of microorganism found by sonication on explanted breast implants. Most guidelines recommend cephalosporins for preoperative antibiotical prophylaxis for breast-implant surgery. CONCLUSION: There is a discrepancy between antibiotic activity of commonly used antibiotics for preoperative prophylaxis of surgical site infections, and microorganisms found by sonication on breast implants, suspected to trigger the formation of capsular contracture. A targeted antibiotic prophylaxis for breast implant surgery with glycopeptides (e.g. Vancomycin) should be considered for the prevention of capsular contracture.

Characterizing the Propionibacterium Load in Revision Shoulder Arthroplasty: A Study of 137 Culture-Positive Cases.

BACKGROUND: Propionibacterium is commonly recovered from explants or surrounding tissues in revision shoulder arthroplasty. Rather than attempting to differentiate a true infection from a false-positive result on the basis of the number of positive cultures, we characterized the amount of these bacteria in each specimen and shoulder. METHODS: The study included 137 revision shoulder arthroplasties from which a minimum of 4 specimens had been submitted for culture and at least 1 was positive for Propionibacterium. Standard microbiology procedures were used to assign a semiquantitative value (0.1, 1, 2, 3, or 4), called the Specimen Propi Value, to the amount of growth in each specimen. The sum of the Specimen Propi Values for each shoulder was defined as the Shoulder Propi Score, which was then divided by the total number of specimens to calculate the Average Shoulder Propi Score. RESULTS: The number and percentage of positive specimen-specific cultures (of material obtained from the stem explant, head explant, glenoid explant, humeral membrane, collar membrane, other soft tissue, fluid, or other) per shoulder ranged from 1 to 6 and 14% to 100%. A high percentage of specimens (mean, 43%; median, 50%) from the culture-positive shoulders showed no growth. Only 32.6% of the fluid cultures were positive in comparison with 66.5% of the soft-tissue cultures and 55.6% of the cultures of explant specimens. The average Specimen Propi Value (and standard deviation) for fluid specimens (0.35 ± 0.89) was significantly lower than those for the soft-tissue (0.92 ± 1.50) and explant (0.66 ± 0.90) specimens (p < 0.001). The Shoulder Propi Score was significantly higher in men (3.56 ± 3.74) than in women (1.22 ± 3.11) (p < 0.001). Similarly, men had a significantly higher Average Shoulder Propi Score (0.53 ± 0.51) than women (0.19 ± 0.43) (p < 0.001). CONCLUSIONS: This investigation suggests that Propionibacterium is unevenly distributed within culture-positive revised shoulders. As a result, the specimen number and source (explant, soft tissue, or fluid) have major influences on the culture results for a revised shoulder arthroplasty. We found no evidence that suggested useful threshold values for defining a true infection. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Selective persistence of Propionibacterium species FMA5 following sealing of infected dentinal matrix.

The objective of the present study was to test the hypothesis that nutrient deprivation by effective isolation should inactivate causative saccharolytic bacteria occupying carious lesions. Vital maxillary third molar teeth were prepared by removing only the superficial necrotic material, leaving behind infected dentinal matrix, before the cavity was sealed with glass ionomer cement (GIC). Before sealing, lesions were biopsied to provide reference bacterial DNA for microbial analysis. After an interval of 10-12 months, the teeth were extracted and, after careful removal of GIC restoration, the underlying dentine was biopsied again for post-treatment microbial analysis. Microbial diversity for nine taxa in 45 carious lesions, before and after minimal intervention therapy, was quantified by real-time polymerase chain reaction (PCR). Except for Propionibacterium sp. FMA5, Fusobacterium nucleatum and Pseudoramibacter alactolyticus, representation of all other taxa showed reduction in the post-restoration biopsy samples. However, Propionibacterium sp. FMA5 was the only species predominantly detected in 80% of the pre-intervention, 82% of the post-restoration and 73% of the paired pre- and post-restoration biopsy samples. The median bacterial load for Propionibacterium sp. FMA5, lactobacilli and bacteria from the family Coriobacteriaceae was higher than the median bacterial load for the remaining six taxa. Significant reduction in the median bacterial load for lactobacilli was evident in post-restoration biopsy samples, implying effective control by GIC after minimal intervention. However, the median bacterial load for Propionibacterium sp. FMA5 increased in post-restoration biopsy samples. Incorporation of antimicrobial agents effective against Propionibacterium species FMA5 could add to more effective conservative management of advanced carious lesions.

Propionibacterium skull base osteomyelitis complicated by internal carotid artery pseudoaneurysm.

The microbiology of skull base osteomyelitis (SBO) is evolving. We present here the first case of SBO caused by Propionibacterium acnes leading to the development of a pseudoaneurysm of the internal carotid artery. Otolaryngologists should recognize this pathogen as a potential cause of invasive temporal bone infection to optimize prompt diagnosis and treatment. Laryngoscope, 127:2337-2339, 2017.

Single-Stage Revision Is Effective for Failed Shoulder Arthroplasty with Positive Cultures for Propionibacterium.

BACKGROUND: Revision shoulder arthroplasties are often culture-positive for Propionibacterium. This study tests the hypothesis that the functional outcomes of revising Propionibacterium culture-positive failed arthroplasties with a single-stage revision and immediate antibiotic therapy are not inferior to the clinical outcomes of revising failed shoulder arthroplasties that are not culture-positive. METHODS: Fifty-five shoulders without obvious clinical evidence of infection had a single-stage revision arthroplasty. The patient self-assessed functional outcomes for shoulders with ≥2 positive cultures for Propionibacterium (the culture-positive group) were compared with shoulders with no positive cultures or only 1 positive culture (the control group). RESULTS: The culture-positive group had 89% male patients, with a mean age (and standard deviation) of 63.5 ± 7.2 years. The mean Simple Shoulder Test (SST) scores for the 27 culture-positive shoulders improved from 3.2 ± 2.8 points before the surgical procedure to 7.8 ± 3.3 points at a mean follow-up of 45.8 ± 11.7 months after the surgical procedure (p < 0.001), a mean improvement of 49% of the maximum possible improvement. The control group had 39% male patients, with a mean age of 67.1 ± 8.1 years. The mean SST scores for the 28 control shoulders improved from 2.6 ± 1.9 points preoperatively to 6.1 ± 3.4 points postoperatively at a mean follow-up of 49.6 ± 11.8 months (p < 0.001), a mean improvement of 37% of the maximum possible improvement. Subsequent procedures for persistent pain or stiffness were required in 3 patients (11%) in the culture-positive group and in 3 patients (11%) in the control group; none of the revisions were culture-positive. Fourteen patients reported side effects to antibiotics. CONCLUSIONS: Clinical outcomes after single-stage revision for Propionibacterium culture-positive shoulders were at least as good as the outcomes in revision procedures for control shoulders. Two-stage revision procedures may not be necessary in the management of these cases. Patients should be educated with regard to potential antibiotic side effects. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Propionibacterium namnetense sp. nov., isolated from a human bone infection.

A polyphasic taxonomic study was performed on two Gram-positive-staining, anaerobic, pleomorphic, rod-shaped strains isolated from human bone and tissue samples. Sequencing of the 16S rRNA genes revealed that the strains belong to a novel species within the genus Propionibacterium, most closely related to Propionibacterium acnes subsp. acnes and Propionibacterium acnes subsp. elongatum with similarity values of 98.4 % and 98.1 %, respectively. In addition, protein-coding genes for rpoB, recA and gyrB clearly separated the novel organism from all species and subspecies of the genus Propionibacterium. However, a DNA-DNA hybridization analysis between the novel organism and the type strain P. acnes ATCC 6919T revealed a value of only 61.1 %. Furthermore, whole genome analysis using the program OrthoANI gave a value of 88.5 %, which is significantly below the cut-off value of 95 % for species delineation. The major fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C17 : 0. The DNA G+C content of the type strain was 59.7 mol%. When taken collectively, phenotypic, molecular genetic, chemotaxonomic and phylogenetic information demonstrate that the organism represents a distinct, albeit close relative of P. acnes On the basis of the results presented, the organism represents a novel member of the genus Propionibacterium for which the name Propionibacterium namnetense sp. nov. is proposed. The type strain is NTS 31307302T (=DSM 29427T=CCUG 66358T).

Propionibacterium in Shoulder Arthroplasty: What We Think We Know Today.

➤ Propionibacterium is a slow-growing gram-positive rod that is part of the normal skin microbiome but can be found on culture of specimens from a large number of patients having revision shoulder arthroplasty performed for pain, stiffness, and component loosening. ➤ Propionibacterium infections do not present with obvious signs of infection, such as swelling, erythema, drainage, or tenderness, but rather are of the so-called stealth type, presenting with unexplained pain, stiffness, or component loosening months to years after the index arthroplasty. ➤ Not all propionibacteria are the same: certain subtypes of Propionibacterium are enriched with virulence factors that may enhance deep infection. ➤ Because propionibacteria typically reside in the pilosebaceous glands of the oily skin of the chest and back, standard surgical skin preparation solutions and even perioperative intravenous antibiotics are often inadequate at sterilizing the incision site; therefore, other prophylactic measures such as meticulous implant handling to avoid contact with dermal structures need to be considered. ➤ Recovery of Propionibacterium from the surgical wounds requires that multiple specimens for culture be taken from different areas of the shoulder to reduce sampling error, and cultures should be held for two weeks on multiple culture media. ➤ Future research efforts can be focused on reducing the risk of implant infection and point-of-care methods for identifying Propionibacterium infections.

Loose glenoid components in revision shoulder arthroplasty: is there an association with positive cultures?

BACKGROUND: Glenoid loosening is one of the most common causes of total shoulder failure. High rates of positive cultures of Propionibacterium and coagulase-negative staphylococcus have been found among shoulders having surgical revision for glenoid loosening. This study reviewed the culture results in a series of surgical revisions for failed total shoulder arthroplasty to determine the relationship between glenoid loosening and positive cultures. METHODS: The medical records of 221 patients without obvious evidence of infection who underwent revision total shoulder arthroplasty were reviewed to examine the association between the security of fixation of the glenoid component and the results of cultures obtained at revision surgery. RESULTS: Of the revised shoulders, 53% had positive cultures; 153 of the shoulders (69%) had a loose glenoid component, whereas 68 (31%) had secure glenoid component fixation. Of the 153 loose glenoid components, 82 (54%) had at least 1 positive culture and 44 (29%) had 2 or more positive cultures of the same microorganism. Similarly, of the 68 secure glenoid components, 35 (51%) had at least 1 positive culture (P = .77) and 14 (21%) had 2 or more positive cultures of the same microorganism (P = .25). Explanted glenoid components that were loose had a higher rate of culture positivity (56% [24/43]) in comparison to explanted glenoid components that were well fixed (13% [1/8]) (P = .05). CONCLUSION: Propionibacterium and coagulase-negative staphylococcus are commonly recovered in revision shoulder arthroplasty, whether or not the glenoid components are loose.

Treatment of prosthetic joint infections due to Propionibacterium. Similar results in 60 patients treated with and without rifampicin.

BACKGROUND AND PURPOSE: Currently, Propionibacterium is frequently recognized as a causative microorganism of prosthetic joint infection (PJI). We assessed treatment success at 1- and 2-year follow-up after treatment of Propionibacterium-associated PJI of the shoulder, hip, and knee. Furthermore, we attempted to determine whether postoperative treatment with rifampicin is favorable. PATIENTS AND METHODS: We conducted a retrospective cohort study in which we included patients with a primary or revision joint arthroplasty of the shoulder, hip, or knee who were diagnosed with a Propionibacterium-associated PJI between November 2008 and February 2013 and who had been followed up for at least 1 year. RESULTS: We identified 60 patients with a Propionibacterium-associated PJI with a median duration of 21 (0.1-49) months until the occurrence of treatment failure. 39 patients received rifampicin combination therapy, with a success rate of 93% (95% CI: 83-97) after 1 year and 86% (CI: 71-93) after 2 years. The success rate was similar in patients who were treated with rifampicin and those who were not. INTERPRETATION: Propionibacterium-associated PJI treated with surgery in combination with long-term antibiotic administration had a successful outcome at 1- and 2-year follow-up irrespective of whether the patient was treated with rifampicin. Prospective studies are needed to determine whether the use of rifampicin is beneficial in the treatment of Propionibacterium-associated PJI.

Detritic synovitis can mimic a Propionibacterium periprosthetic infection.

PURPOSE: The purpose of this article is to illustrate that the clinical findings of detritic synovitis complicating a total shoulder arthroplasty can strongly resemble those of a 'stealth' periprosthetic shoulder infection with a low-virulence organism such as Propionibacterium. METHODS: We present a review of the literature and illustrate an example of detritic synovitis following a total shoulder arthroplasty. RESULTS: The combination of glenoid component loosening and humeral osteolysis after total shoulder arthroplasty are commonly attributed to periprosthetic infection with low virulence organisms, such as Propionibacterium or coagulase negative Staphylococcus. Such a periprosthetic infection can appear long after the index joint replacement. This article points out that these same findings may occur with a non-infectious process initiated by polyethylene, cement or metal debris-detritic synovitis. CONCLUSIONS: At present, the important differentiation between these two etiologies can only be ascertained by awaiting the results of cultures obtained at the time of revision surgery.