The incidence of subclinical infection in patients undergoing revision shoulder stabilization surgery: a retrospective chart review.

BACKGROUND: Shoulder instability continues to be a common problem that is difficult to treat. Part of this difficulty can be attributed to the numerous postoperative complications that can impact the clinical course. Our study aims to primarily identify the incidence of subclinical infection in patients undergoing revision shoulder stabilization surgery and secondarily identify any risk factors for developing a subclinical infection. MATERIALS AND METHODS: From January 2012 to December 2022, 94 charts of patients who underwent revision surgery by the senior author after a previous arthroscopic or open stabilization surgery for shoulder instability were reviewed. All patients of any age who underwent either bony or soft tissue revision surgery, regardless of the number of previous surgeries or corticosteroid injections, were included. Patients were excluded if they had a previous infection in the shoulder, if there was no record of the procedures performed in the previous surgery, or if cultures were not available for review. For each patient, demographic information (age, sex, race, smoking status, previous corticosteroid injections, malnutrition, renal failure, liver failure, diabetes mellitus, immunocompromised status, and intravenous drug use), surgical information (procedures performed, type of surgery, and date of surgery), and culture results were recorded. RESULTS: Overall, 107 patients were included in our study. Twenty-nine patients (27.1%) had positive cultures (60 cultures in total). Twenty-six patients had positive Cutibacterium acnes (C. acnes) cultures. On average, C. acnes cultures took 10.65 days to turn positive, whereas 24 of 27 patients had cultures that were positive within 14 days of the culture being obtained. There was no difference in infection incidence rates between soft tissue and bony stabilization procedures (P = .86) or arthroscopic and open procedures (P = .59). Males were more than 5 times more likely than females to be culture positive in our cohort (93.1% vs. 73.1%, relative risk [RR] = 1.27, P = .03). Finally, 10 control cultures were taken from the operating room air environment (8 distinct surgeries had 1 control culture taken, whereas 1 surgery had 2), 2 of which were positive for C. acnes (both taken from the same patient operation). This patient had their shoulder cultures positive for C. acnes as well. CONCLUSION: More than a quarter of patients requiring revision surgery after shoulder stabilization procedures have a subclinical shoulder infection, with males being at a higher risk of developing an infection than females. Surgeons should always consider infection as a reason for the lack of clinical improvement and possibly needing revision surgery after shoulder stabilization. The prompt diagnosis and treatment of these infections could be vital in improving results after these surgeries.

The POSI study: gender differences in 94 cases of postoperative shoulder surgery infection: results of a 7-year retrospective multicenter study.

BACKGROUND: Contrary to lower limb infection, POstoperative Shoulder surgery Infection (POSI) often involves Cutibacterium acnes. Our aim was to describe patient characteristics and pathogens retrieved in POSI to guide initial empiric antibiotic selection with suspected infection during revision. We also compared microorganisms in infection following trauma, arthroplasty (AP), and arthroscopy (AS). METHODS: A multicenter retrospective study from 2010 to 2016 reviewed laboratory databases and medical records to identify patients with a previous shoulder surgery and a confirmed shoulder infection. The following procedures were included: AP, AS, fracture fixation (FF), and another open surgery (OS). A confirmed shoulder infection was defined as 2 positive cultures or more of the same microorganism, or clear clinical infection with 1 positive culture or more. RESULTS: Among the 5 hospitals and 28 surgeons involved, 94 POSI cases were identified. Mean age was 59 years at index surgery (range: 22-91) with a majority of men (n = 70, 74%). Among POSI cases, AP was the most common index surgery (n = 41), followed by FF (n = 27), AS (n = 16), and OS (n = 10). The median time between index surgery and the first positive sample was 5 months and the mean was 23 months (minimum 6 days to maximum 27 years), illustrating a positively skewed distribution. Cutibacterium spp were identified in 64 patients (68%), including 59 C acnes patients (63%), which was the most frequent germ in all 4 surgical groups. In 86% of cases, C acnes was identified at the first revision. The other 2 most common germs were Staphylococcus epidermidis and Staphylococcus aureus, with 29% and 17%, respectively. Polymicrobial infection was present in 30% of patients. Gender analysis revealed that C acnes was twice as frequent in men (male = 52 of 70, female = 7 of 24; P < .001). S epidermidis was more prevalent in women (n = 11; 46%) compared with men (n = 16; 21%) (P = .032). C acnes infection was most frequent in arthroscopic surgery (n = 14; 70%, P = .049). S epidermidis was 3 times more prevalent in chronic than in acute cases. CONCLUSION: Empiric antimicrobial therapy following POSI, while waiting for culture results, should cover C acnes, S epidermidis, and S aureus. There is a significant gender difference regarding POSI culture results. C acnes is more frequent in men, but should still be covered in women as it was found in 29% of cases.

Preoperative topical benzoyl peroxide treatment is effective in reducing Cutibacterium acnes in shoulder surgery: a systematic review.

BACKGROUND: Cutibacterium acnes (C acnes) colonization can have a significant impact on patients undergoing both arthroscopic and open shoulder surgery with regard to postoperative infection. Its resistance to standard preoperative skin preparations and prophylactic antibiotics has led to a need for a more targeted therapy. Topical benzoyl peroxide (BPO) has been used by dermatologists in the treatment for acnes due to its bactericidal and penetrative effects through the dermal layer. The aim of this systematic review is to review the effectiveness of topical BPO preoperatively in shoulder surgery in reducing C acnes colonization and postoperative infection. METHODS: A review of the online databases Medline and Embase was conducted on December 15, 2021, according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The review was registered prospectively in the PROSPERO database. Clinical studies reporting superficial and deep sample microbiology and postoperative complications were included. The studies were appraised using the revised Cochrane Risk of Bias 2 (ROB 2) tool for randomized studies and the Methodological Index for Non-Randomized Studies (MINORS) tool. RESULTS: The search strategy identified 10 studies for inclusion (6 randomized control trials, 2 prospective cohort studies, and 2 case series), including a total of 482 patients. Seven studies were comparable, testing BPO against alternative standard skin preparations. Of the 10 studies, 7 showed a decrease in the load of C acnes on the skin and/or deep tissues, of which 6 demonstrated statistical significance. Men were shown to have a statistically significant increase in the colonization rate of C acnes. Scheer et al (2021) demonstrated 4500 colony-forming units/mL in males and 900 colony-forming units/mL in females. In studies where the number of BPO applications was higher, BPO appeared more effective. Dizay et al demonstrated C acnes elimination in 78.9% with more than 1 application compared with 66.7% if only applied once. Three studies looked at the effectiveness of BPO during the operative timeline with 1 demonstrating its statistically significant effectiveness at reducing colonization 2 hours into the operation (P = .048). CONCLUSION: BPO is effective as a topical treatment at reducing C acnes colonization before shoulder surgery. However, the relationship between duration of treatment, frequency of application, and gender requires further research.

Are Cutibacterium acnes present at the end of primary shoulder prosthetic surgeries responsible for infection? Prospective study.

The purpose of this study was to investigate if the C. acnes present at the end of a primary shoulder arthroplasty could be responsible for shoulder arthroplasty infection. Prospective study includes patients undergoing primary shoulder arthroplasty from January 2015 until December 2018. From all the patients included, 5 to 12 tissue samples were obtained and were specifically cultured to detect the presence of C. acnes. DNA was extracted from the C acnes isolated colonies and Whole Genome Sequencing (WGS) analysis was done. A cohort of 156 patients was finally included. In twenty-seven patients, the C. acnes was present at the end of the primary surgery. Two of these patients developed a C. acnes periprosthetic shoulder infection at 6 and 4 months after the primary surgery. WGS of C. acnes isolated colonies showed that all the revision-surgery isolates clustered near to the corresponding primary-surgery isolates compared to the other independent bacterial colonies. (99.89% of similarity). C. acnes present at the end of the primary surgery can be the cause of early or delayed periprosthetic joint infections in shoulder arthroplasty.

Techniques for Decreasing Bacterial Load for Open Shoulder Surgery.

¼: Benzoyl peroxide (BPO) 5% has been shown to reduce Cutibacterium acnes load on the skin. BPO 5% with miconazole nitrate (MN) 2% may be beneficial, whereas BPO 5% with clindamycin cream 1% to 1.2% does not seem to have additive effects when compared with BPO 5% alone. Chlorhexidine gluconate solutions reduce the total bacterial load on the skin, but do not seem to have a significant effect on C. acnes. ¼: ChloraPrep seems to be the best surgical skin preparation to decrease overall positive skin cultures. Preincisional hydrogen peroxide 3% application has been shown to be a cost-effective practice to inhibit growth of C. acnes. Vancomycin powder before deltopectoral interval closure has antimicrobial effects against C. acnes and is a cost-effective practice. Finally, Bactisure surgical lavage is protective against the formation of biofilms. ¼: IV cefazolin has been shown to be more effective for shoulder arthroplasty infection prophylaxis than antibiotic alternatives such as vancomycin. Thus, patients with a questionable history of penicillin allergy should undergo additional testing. ¼: For shoulder surgery infection prophylaxis, we recommend the use of BPO 5% cream for 5 days preoperatively with chlorhexidine wipes the night before and the morning of surgery. IV cefazolin should be administered perioperatively, and patients with a questionable history of penicillin allergy should be tested. Surgeons should consider preincisional application of hydrogen peroxide 3% for 5 minutes, followed by standard ChloraPrep preparation. Normal saline should be used for preclosure lavage. Finally, application of vancomycin powder deep to the deltopectoral interval closure should be considered.

Comparison of the antimicrobial efficacy of povidone-iodine-alcohol versus chlorhexidine-alcohol for surgical skin preparation on the aerobic and anaerobic skin flora of the shoulder region.

BACKGROUND: Cutibacterium acnes is part of the anaerobic skin microbiome and resides in deeper skin layers. The organism is an agent of surgical site infections (SSI) in shoulder surgery. We hypothesized that prolonged skin preparation with an agent that penetrates deeply into the skin would be beneficial. Thus, we compared two classes of antiseptics, each combined with alcohol, each applied with two different contact times. METHODS: Using a cross-over arrangement, shoulders of 16 healthy volunteers were treated for 2.5 min (standard) or 30 min (prolonged) with alcohol-based chlorhexidine (CHG-ALC) or alcohol-based povidone-iodine (PVP-I-ALC). Skin sites were sampled before, immediately after, and 3 h after treatment, using a standardized cup-scrub technique. RESULTS: Aerobic skin flora was reduced more effectively by PVP-I-ALC than by CHG-ALC after 2.5 min application and immediate sampling (reduction factor [RF] 2.55 ± 0.75 vs. 1.94 ± 0.91, p = 0.04), but not after prolonged contact times and 3-h sampling. Coagulase-negative staphylococci were completely eliminated after PVP-I-ALC application, but still recovered from 4 of 32 samples after CHG-ALC application. Anaerobic flora was reduced more effectively by PVP-I-ALC than CHG-ALC after standard (RF 3.96 ± 1.46 vs. 1.74 ± 1.24, p < 0.01) and prolonged (RF 3.14 ± 1.20 vs. 1.38 ± 1.16, p < 0.01) contact times and immediate sampling, but not after 3-h sampling. No adverse events were reported. CONCLUSIONS: PVP-I-ALC showed marginal benefits concerning the aerobic flora, but more substantial benefits over CHG-ALC concerning the anaerobic flora of the shoulder. Standard and prolonged contact times showed superiority for PVP-I-ALC for anaerobic flora at all immediate sampling points, but missed significance at 3-h sampling. The results underscore the need for protection against C. acnes and coagulase-negative staphylococci in orthopaedic surgery. The clinical relevance of these findings, however, should be studied with SSI as an endpoint.

Enterobacter cloacae infection of the shoulder in a 52-year-old woman without apparent predisposing risk factor: a case report and literature review.

BACKGROUND: Enterobacter cloacae (E. cloacae) is one of the commensal flora in the human intestinal tract and a prevalent nosocomial pathogen, which rarely causes infectious osteoarthritis in immunocompetent patients without recent trauma or surgery. Here, we report the first case of septic monoarthritis of the shoulder caused by E. cloacae in an immunocompetent patient. CASE PRESENTATION: A 52-year-old female with a 6-year history of right shoulder pain was referred to our emergency department due to fever, acute severe shoulder pain, and swelling. Blood test showed elevated inflammatory markers. The patient denied any recent invasive surgical procedure and trauma. She was misdiagnosed with a frozen shoulder, and the anti-inflammatory painkiller celecoxib for symptomatic treatment was ineffective. Magnetic resonance imaging (MRI) showed a shoulder joint abscess and supraspinatus tendon tear. The joint aspirate culture showed E. cloacae. After late diagnosis, she was treated with levofloxacin and underwent surgical debridement and irrigation. Her follow-up data revealed that she did not suffer from shoulder swelling and severe pain. CONCLUSION: This is a rare case of E. cloacae infected arthritis of the shoulder in an immunocompetent patient with a rotator cuff tear, indicating that even if the symptoms and age of the patients match the characteristics of frozen shoulder, the possibility of septic arthritis should be considered in the presence of fever and increasing inflammatory markers. The cases of our literature review suggest that the patients subjected to invasive procedure may develop a subsequent E. cloacae osteoarticular infection, regardless of being asymptomatic after the procedure.

Septic arthritis of the shoulder due to Ureaplasma urealyticum after emergency caesarean section: a case report.

BACKGROUND: Ureaplasma urealyticum is an intra-cellular bacterium frequently found colonizing the genital tract. Known complications include localized infections, which can result in premature deliveries. Septic arthritis due to U. urealyticum in healthy patients is exceptionally rare, although opportunistic septic arthritis in agammaglobulinemic patients have been reported. However, there are no reports of septic arthritis due to U. urealyticum following caesarean section or in the post-partum period. CASE PRESENTATION: A 38-year-old immunocompetent woman presented with severe right shoulder pain, 1 month following emergency caesarean section at 26 weeks of gestation for pre-eclampsia and spontaneous placental disruption with an uncomplicated post-operative recovery. Our suspicion of septic arthritis was confirmed with abundant pus following arthrotomy by a delto-pectoral approach. Awaiting culture results, empirical antibiotic treatment with intravenous amoxicilline and clavulanic acid was initiated. In spite of sterile cultures, clinical evolution was unfavorable with persistent pain, inflammation and purulent drainage, requiring two additional surgical débridement and lavage procedures. The 16S ribosomal RNA PCR of the purulent liquid was positive for U. urealyticum at 2.95 × 106 copies/ml, specific cultures inoculated a posteriori were positive for U. urealyticum. Levofloxacin and azithromycine antibiotherapy was initiated. Susceptibility testing showed an intermediate sensibility to ciprofloxacin and clarithromycin. The strain was susceptible to doxycycline. Following cessation of breastfeeding, we started antibiotic treatment with doxycycline for 4 weeks. The subsequent course was favorable with an excellent functional and biological outcome. CONCLUSIONS: We report the first case of septic arthritis due to U. urealyticum after caesarean section. We hypothesize that the breach of the genital mucosal barrier during the caesarean section led to hematogenous spread resulting in purulent septic arthritis. The initial beta-lactam based antibiotic treatment, initiated for a purulent arthritis, did not provide coverage for cell wall deficient organisms. Detection of 16S rRNA allowed for a correct microbiological diagnosis in a patient with an unexpected clinical course.

Efficacy of Home Prophylactic Benzoyl Peroxide and Chlorhexidine in Shoulder Surgery: A Systematic Review and Meta-Analysis.

Two predominant prophylactic home skin-disinfection regimens exist in shoulder surgery, benzoyl peroxide and chlorhexidine. Of these 2 regimens, benzoyl peroxide gel is more effective than chlorhexidine in reducing the rate of positive Cutibacterium cultures on the skin surface. At present, there are no studies that assess the impact of these home prophylactic measures on clinical infection rates.

Incidence of Cutibacterium acnes from shoulder arthroplasties in Asians: ethnic differences should be considered.

BACKGROUND: Most studies on Cutibacterium acnes in shoulder surgery have been conducted in the Western population, and studies on Asians are rare. We evaluated the incidence and risk factors of C acnes in shoulder arthroplasty in Asians. METHODS: We retrospectively analyzed 154 patients between January 2017 and May 2019 who underwent shoulder arthroplasty. Swabs were taken after skin preparation from the skin surface of the anterior acromion, axilla, and joint fluid to study the incidence of C acnes. Before skin preparation we also collected swabs from the anterior acromion, axilla, and thigh from 59 of the 154 patients. RESULTS: Eight of 154 patients after and 6 of 59 patients before skin preparation were positive for C acnes. C acnes were found in 2 patients at the anterior acromion and in 6 at the synovial joint after skin preparation and in 1 patient at the axilla, in 5 at the anterior acromion, and in 3 at the thigh before preparation. History of steroid injection and number of steroid injections were significantly associated with C acnes isolation (P = .039 and P = .006, respectively), whereas age, sex, body mass index, shoulder surgery history, hypertension, diabetes, and cerebrovascular disease were not, as were serum inflammatory markers, including white blood cell count, C-reactive protein level, and erythrocyte sedimentation rate. CONCLUSION: A total of 5.2% of the patients after skin preparation and 10.2% of patients before skin preparation were found to be positive for C acnes. The incidence of C acnes in patients who underwent shoulder arthroplasties in Asia was low and, thus, ethnic differences should be considered for C acnes. The history and number of steroid injections were associated with isolation of C acnes.

Cutibacterium subtype distribution on the skin of primary and revision shoulder arthroplasty patients.

BACKGROUND: The skin of healthy shoulders is known to harbor multiple different subtypes of Cutibacterium (formerly Propionibacterium) acnes at the same time. C acnes can often be isolated from deep tissue and explant samples obtained during revision of a failed shoulder arthroplasty, presumably because the shoulder was inoculated with organisms from the patient's skin at the time of the index arthroplasty. It is possible that specific subtypes or distributions of subtypes may be associated with an increased pathogenic potential and that the skin of patients undergoing revision arthroplasty contains different distributions of the subtypes than in patients undergoing primary arthroplasty. We analyzed the subtype distribution of Cutibacterium from the skin of shoulders undergoing revision arthroplasty vs. primary arthroplasty. METHODS: Preoperative skin swabs were collected from 25 patients who underwent primary shoulder arthroplasty and 27 patients who underwent revision shoulder arthroplasty. The results of semiquantitative cultures of the skin and deep tissues were reported as specimen Cutibacterium values, and scores from all deep tissue samples were added to report the total shoulder Cutibacterium score. Single-locus sequence typing (SLST) of C acnes from the skin swabs was used to determine the subtype distribution for each patient. The percentage of each subtype for each patient was averaged in patients undergoing revision arthroplasty and then compared with that in patients undergoing primary arthroplasty. RESULTS: The C acnes subtype distribution on the skin of revision arthroplasty patients was different from that of primary shoulder arthroplasty patients, with a significantly higher percentage of SLST subtype A (36.9% vs. 16.0%, P = .0018). The distribution of SLST subtypes was similar between revision arthroplasty patients with strongly positive culture findings vs. those with weakly positive or negative culture findings. CONCLUSIONS: Significant differences in the skin Cutibacterium subtype distributions were found between shoulders undergoing revision shoulder arthroplasty and those undergoing primary shoulder arthroplasty. Future studies are needed to determine whether certain Cutibacterium subtype distributions are associated with an increased risk of arthroplasty revision.

Empyema necessitatis due to Pseudomonas aeruginosa in a child with cerebral palsy.

Empyema necessitatis (EN) is a rare complication of empyema in which the pleural infection spreads outside the pleural space. Lower airway infections are common among children with cerebral palsy (CP). Although harmless to healthy individuals, Pseudomonas aeruginosa can cause invasive infections, including CP, in immunocompromised hosts. Mycobacterium tuberculosis and Actinomyces spp. have been reported as common causative organisms of EN. However, EN caused by P. aeruginosa has never been reported. We report the case of an 8-year-old girl with CP without tracheotomy who was admitted to our hospital with complaints of fever and increased epileptic seizures. First, she was diagnosed with pneumonia and treated with antibiotics. However, seven days after admission, a palpable mobile mass overlying the lower part of the shoulder blade was noticed. Enhanced magnetic resonance imaging revealed broad high signal area on T2-weighted and diffusion-weighted images, indicating empyema of the left lower lung that had penetrated the pleural wall and spread to the subcutaneous area of the left back. Thus, she was diagnosed with EN. Twelve days after admission, P. aeruginosa was detected from the pus culture. Patients with CP who have chronic lung diseases, such as pneumonia, atelectasis, or empyema, may need careful follow up.

Benzoyl peroxide use transiently decreases Cutibacterium acnes load on the shoulder.

BACKGROUND: Cutibacterium acnes is the most common pathogen in shoulder prosthetic joint infections. Short-contact benzoyl peroxide (BPO) solutions effectively reduce C acnes loads on the shoulder preoperatively. It is unknown how long the effect of BPO lasts. We evaluated C acnes counts 1 week after BPO application. We hypothesized that BPO would decrease C acnes burden with a rebound after 1 week. METHODS: Screening of 102 healthy volunteers with no history of shoulder surgery or C acnes infection was performed to establish bacterial counts. Thirty-four participants were selected based on an established threshold. Each was given BPO 5% for 3 consecutive days of application on either the left or right shoulder as indicated by a random number generator. Deep sebaceous gland cultures were obtained with a detergent scrub technique before BPO application, after 3 days of use, and 1 week after BPO treatment commenced. RESULTS: The differences between the logarithmic reduction and the logarithmic rebound at the anterior, lateral, and posterior sites were statistically significant. Anteriorly, the average log reduction was -0.44 and the average log rebound was 0.69 (P = .003). Laterally, reduction was -0.64 and rebound was 0.74 (P = .003). Posteriorly, reduction was -0.63 and rebound was 0.78 (P = .008). At the axilla, reduction was -0.40 and rebound was 0.31 (P = .10). The differences in C acnes burden between pretreatment and 1-week counts at all sites were not statistically significant. CONCLUSION: A significant decrease in C acnes burden occurred after BPO application but was not permanent. Significant rebound occurred just 1 week later.

Multi-focal Clostridioides (Clostridium) difficile osteomyelitis in a patient with sickle cell anemia: case presentation and literature review.

Clostridioides (Clostridium) difficile infection manifests as intestinal infections, namely pseudomembranous colitis. The occurrence of extra-intestinal disease is thought to be rare with a rate of 1.08% of 2034 isolates of C. difficile and an incidence of 4/100,000 admissions. C. difficile had been rarely associated with osteomyelitis. Here, we report the occurrence of C. difficile osteomyelitiin a patient with sickle cell disease. The patient had multiple surgeries and a prolonged antimicrobial therapy to achieve a cure. The patient had C. difficile infection of native bone and of a prosthetic joint. The patient received prolonged therapy with amoxicillin-clavulanic acid and metronidazole and she remained free of C. difficile infection for 3 years off antibiotics.

Kingella kingae Septic Arthritis in an Older-Than-Expected Child.

Kingella kingae typically causes musculoskeletal infection in young children between the ages of 6 months and 4 years who may be in close contact with other similarly aged children who are colonized with the organism in their oropharynx. Kingella infections have rarely been described in older individuals with chronic medical conditions or immune compromise. This is a case report of a healthy, older child who developed an invasive infection due to Kingella kingae. Clinical and laboratory details are provided of an otherwise healthy 11-year-old female who developed an acute onset of septic arthritis of her shoulder. The organism was identified by culture and 16S polymerase chain reaction. Her clinical course necessitated an antibiotic change after the organism was correctly identified. The affected child had close contact with a 2-year-old sibling who recently had a viral upper respiratory infection. This case illustrates the potential for Kingella kingae to rarely cause invasive infection in older, healthy children. Supplemental laboratory techniques may be helpful to identify this organism. Although it is reasonable to limit the antibiotic spectrum for older children, clinicians should be aware of this possibility, particularly if there is a history of close contact with young children.

Emergence of an extensively drug-resistant (XDR) Streptococcus pneumoniae serotype 15A by capsular switching.

Recently, we have identified an extensively drug-resistant (XDR) Streptococcus pneumoniae serotype 15A isolate from a patient with bacterial meningitis. It belonged to sequence type 8279 (ST8279), a clone identified as XDR serotype 11A isolated in South Korea. We obtained and compared the genome sequences of an XDR 15A and an XDR 11A isolate. The genomes of two XDR isolates were highly identical, except for the capsular polysaccharide (cps) locus and another small region. Capsular switching from 11A to 15A may have occurred via recombination of the cps locus. The emergence of a new XDR clone via capsular switching would be a great concern for public health and in clinical settings.

Cutibacterium acnes and the shoulder microbiome.

BACKGROUND: Advances in DNA sequencing technologies have made it possible to detect microbial genome sequences (microbiomes) within tissues once thought to be sterile. We used this approach to gain insights into the likely sources of Cutibacterium acnes (formerly Propionibacterium acnes) infections within the shoulder. METHODS: Tissue samples were collected from the skin, subcutaneous fat, anterior supraspinatus tendon, middle glenohumeral ligament, and humeral head cartilage of 23 patients (14 male and 9 female patients) during primary arthroplasty surgery. Total DNA was extracted and microbial 16S ribosomal RNA sequencing was performed using an Illumina MiSeq system. Data analysis software was used to generate operational taxonomic units for quantitative and statistical analyses. RESULTS: After stringent removal of contamination, genomic DNA from various Acinetobacter species and from the Oxalobacteraceae family was identified in 74% of rotator cuff tendon tissue samples. C acnes DNA was detected in the skin of 1 male patient but not in any other shoulder tissues. CONCLUSION: Our findings indicate the presence of a low-abundance microbiome in the rotator cuff and, potentially, in other shoulder tissues. The absence of C acnes DNA in all shoulder tissues assessed other than the skin is consistent with the hypothesis that C acnes infections are derived from skin contamination during surgery and not from opportunistic expansion of a resident C acnes population in the shoulder joint.

Topical benzoyl peroxide application on the shoulder reduces Propionibacterium acnes: a randomized study.

BACKGROUND: Propionibacterium acnes is a common cause of infection following shoulder surgery. Studies have shown that standard surgical preparation does not eradicate P acnes. The purpose of this study was to examine whether topical application of benzoyl peroxide (BPO) gel could decrease the presence of P acnes compared with today's standard treatment with chlorhexidine soap (CHS). We also investigated and compared the recolonization of the skin after surgical preparation and draping between the BPO- and CHS-treated groups. METHODS: In this single-blinded nonsurgical study, 40 volunteers-24 men and 16 women-were randomized to preoperative topical treatment at home with either 5% BPO or 4% CHS on the left shoulder at the area of a deltopectoral approach. Four skin swabs from the area were taken in a standardized manner at different times: before and after topical treatment, after surgical skin preparation and sterile draping, and 120 minutes after draping. RESULTS: Topical treatment with BPO significantly reduced the presence of P acnes measured as the number of colony-forming units on the skin after surgical preparation. P acnes was found in 1 of 20 subjects in the BPO group and 7 of 20 in the CHS group (P = .044). The results remained after 2 hours (P = .048). CONCLUSION: Topical preparation with BPO before shoulder surgery may be effective in reducing P acnes on the skin and preventing recolonization.

Periprosthetic Joint Infection of Shoulder Arthroplasties: Diagnostic and Treatment Options.

Periprosthetic joint infection (PJI) is one of the most frequent reasons for painful shoulder arthroplasties and revision surgery of shoulder arthroplasties. Cutibacterium acnes (Propionibacterium acnes) is one of the microorganisms that most often causes the infection. However, this slow growing microorganism is difficult to detect. This paper presents an overview of different diagnostic test to detect a periprosthetic shoulder infection. This includes nonspecific diagnostic tests and specific tests (with identifying the responsible microorganism). The aspiration can combine different specific and nonspecific tests. In dry aspiration and suspected joint infection, we recommend a biopsy. Several therapeutic options exist for the treatment of PJI of shoulder arthroplasties. In acute infections, the options include leaving the implant in place with open debridement, septic irrigation with antibacterial fluids like octenidine or polyhexanide solution, and exchange of all removable components. In late infections (more than four weeks after implantation) the therapeutic options are a permanent spacer, single-stage revision, and two-stage revision with a temporary spacer. The functional results are best after single-stage revisions with a success rate similar to two-stage revisions. For single-stage revisions, the microorganism should be known preoperatively so that specific antibiotics can be mixed into the cement for implantation of the new prosthesis and specific systemic antibiotic therapy can be applied to support the surgery.