Propionibacterium avidum: A Virulent Pathogen Causing Hip Periprosthetic Joint Infection

First case of Cutibacterium avidum-infected pelvic lymphocele post-lymphadenectomy for endometrial cancer: A case report

Background

Pelvic lymphocele (lymphocyst) infection after lymphadenectomy is a rare complication that can cause the spread of inflammation to neighboring organs whose microbiology is not well known. Cutibacterium avidum causes various infections. However, no case reports of C. avidum pelvic lymphocele infection are available; therefore, its clinical characteristics in pelvic lymphocele infections remain unknown.

Case presentation

A 38-year-old woman with obesity (body mass index: 38.1 kg/m2) and a history of pelvic lymphadenectomy and chemotherapy for endometrial cancer presented with worsening left lower quadrant (LLQ) pain with fever. Physical examination revealed decreased abdominal bowel sounds and tenderness on LLQ palpation with no signs of peritonitis. Computed tomography (CT) revealed an infected left pelvic lymphocele with inflammation spreading to the adjacent sigmoid colon. Following blood culture, ampicillin/sulbactam (2 g/1 g every 6 h) was administered intravenously. Anaerobic culture bottles revealed gram-positive rods on day 4 of incubation at 37 °C. No other disseminated foci were observed in enhanced whole-body CT and upon transthoracic echocardiography. The isolates grew aerobically and anaerobically on blood agar plates with strong hemolysis. The bacterium was identified as C. avidum using a combination of characteristic peak analysis with matrix-assisted laser desorption ionization (MALDI) and 16S rRNA gene sequencing. The patient was diagnosed with C. avidum pelvic lymphocele infection. Based on penicillin susceptibility, the patient was successfully treated with intravenous ampicillin/sulbactam and de-escalated with intravenous ampicillin (2 g every 6 h) for 10 days, followed by oral amoxicillin (2000 mg/day) for an additional 11 days without drainage.

Conclusions

C. avidum should be considered a causative microorganism of pelvic lymphocele infection. Peak analysis using MALDI and distinctive growth on blood agar plates are suitable for identifying C. avidum. Mild pelvic lymphocele caused by C. avidum can be treated with a short course of appropriate antimicrobial treatment without surgical intervention.

The value of sonication on orthopaedic implants in an everyday clinical setting - an exploratory study

BACKGROUND

Sonication of removed orthopaedic implants in suspected implant-associated infections (IAI) is widely applied internationally. However, evaluation of the utility of sonication on all implants removed in everyday standard practice is scarce. This exploratory study was performed to evaluate the application of sonication fluid (SF) culture on removed orthopaedic implants, irrespective of the reason for removal.

METHODS

Out of 100 removed orthopaedic implants collected between August 2019 and September 2020, 77 implants with availability of concurrent tissue culture samples were included in the study. Removed implants were categorized into a confirmed or suspected IAI group and a presumed aseptic group based on pre-operative diagnosis by the responsible surgeon. Implants were sonicated and SF culture performed under both aerobic and anaerobic conditions. The significance of all bacterial isolates was evaluated based on the CFU/mL cut-offs of the EBJIS guidelines, except for C. acnes where additional investigations were performed.

RESULTS

The results of SF culture in the two groups were compared with their corresponding tissue cultures. Out of the 12 cases in the confirmed/suspected IAI group, SF culture was positive in 11 cases and had increased diagnostic yield in two (17%) cases compared to tissue culture. Increased diagnostic yield of SF compared to tissue culture was seen in seven (11%) of the 65 implants in the presumed aseptic group. If growth of Cutibacterium species isolates were interpreted based on EBJIS cut-off for SF culture instead of the study-specific criteria, then two isolates considered to represent infection might have been missed while three other isolates considered contaminants would have fallen under the 'infection confirmed' category in the EBJIS guidelines.

CONCLUSION

Sonication with SF culture has increased diagnostic yield compared to tissue cultures in all implants irrespective of reason for removal. However, positive SF cultures with Cutibacterium species should always be interpreted with extreme care.

In Vivo Emergence of Dual Resistance to Rifampin and Levofloxacin in Osteoarticular Cutibacterium avidum

Cutibacterium avidum is an emerging causative agent of orthopedic device-related infections (ODRIs). There are no guidelines for the antimicrobial treatment of C. avidum ODRI, but oral rifampin is frequently used in combination with a fluoroquinolone following intravenous antibiotics. We describe the in vivo emergence of combined resistance to rifampin and levofloxacin in a C. avidum strain isolated from a patient with early-onset ODRI treated with debridement, antibiotic treatment, and implant retention (DAIR) using rifampin combined with levofloxacin as the oral treatment. Whole-genome sequencing of C. avidum isolates before and after antibiotic exposure confirmed strain identity and identified new mutations in rpoB and gyrA, leading to amino acid substitutions previously reported to be associated with resistance to rifampin (S446P) and fluoroquinolones (S101L), respectively, in other microbial agents, in the posttherapy isolate. Aside from the molecular insights reported here, this study highlights potential limitations of the combination of oral rifampin and levofloxacin in patients undergoing a DAIR procedure for C. avidum ODRI and the potential need to evaluate specific optimal therapy for emerging ODRI pathogens. IMPORTANCE In this study, we report for the first time the in vivo emergence of dual resistance to levofloxacin and rifampin in C. avidum isolated from a patient who received both antibiotics orally in the setting of a salvage debridement and implant retention of an ODRI. Aside from the molecular insights reported here, this study highlights potential limitations of the combination of oral rifampin and levofloxacin in patients undergoing these surgical procedures and the potential need to evaluate specific optimal therapy for emerging ODRI pathogens.

Cutibacterium positive cultures in total joint arthroplasty: a comparison of the hip, knee, and shoulder

PURPOSE

Cutibacterium spp. (formerly Propionibacterium) is a slow growing, Gram-positive, anaerobic bacteria and is an emerging clinical entity in prosthetic joint infection (PJI). This study compares the presentation, surgical management, and post-operative antibiotic therapy of patients with positive intraoperative cultures during revision total joint arthroplasty (TJA) of the hip, knee, and shoulder.

METHODS

This was a retrospective cohort study of patients from 2014 to 2020 of 57 revision TJAs (27 total hip arthroplasty (THA), 17 total shoulder arthroplasty (TSA), and 13 total knee arthroplasty (TKA)) with intraoperative cultures positive for Cutibacterium at a tertiary academic centre. Patient demographics, pre-operative labs, radiographs, and aspirate results were collected. Intraoperative data was reviewed. Post-operative antibiotic therapy and repeat infections were recorded. Data was compared with univariate analyses.

RESULTS

There was no significant difference in pre-operative lab values between the cohorts. All cohorts had > 58% radiographic lucency. Revision TSA patients had significantly fewer pre-operative aspirates. Six patients undergoing revision THA, three TKA and one TSA had a repeat infection requiring further surgery. Four in the THA cohort and one in the TKA cohort with repeat infections did not receive prolonged antibiotic therapy.

CONCLUSION

Cutibacterium is an infectious agent that can present in an indolent fashion after TJA. It commonly causes progressive radiographic lucency. The workup and post-operative management differs in the hip, knee, and shoulder, which is likely due to existing literature guiding physician practice. In all joints, Cutibacterium is a virulent pathogen that can cause repeat infections requiring surgical treatment.

Cutibacterium Positive Cultures in Total Hip Arthroplasty: Contaminant or Pathogen?

BACKGROUND

Cutibacterium spp. is an emerging pathogen in total hip arthroplasty (THA) that is not well evaluated in the literature. This study reported on the presentation and management of THA complicated by positive intraoperative Cutibacterium cultures.

METHODS

This is a retrospective review of 27 revision THAs with positive monomicrobial intraoperative Cutibacterium cultures from 2014 to 2020 at one academic center. These patients were divided into two cohorts based on meeting Musculoskeletal Infection Society (MSIS) criteria for prosthetic joint infections (PJI). Patient demographics, preoperative labs, and hip aspirate results were collected. Procedure performed, postoperative antibiotic regimens, and repeat infections were recorded. Data were compared with univariate analysis.

RESULTS

Nine of the 27 patients preoperatively met MSIS criteria for PJI. Patients with positive MSIS criteria had significantly higher median synovial cell count (P = .048) and neutrophil percentage in a preoperative aspirate (P = .050). Eight patients with positive MSIS criteria received six weeks of postoperative antibiotics compared to two patients with negative criteria. Two patients with positive MSIS criteria had a postoperative infection that required further surgical intervention. Four patients with negative criteria who required further surgical intervention did not receive postoperative antibiotics after initial revision.

CONCLUSION

While often categorized as a contaminant, Cutibacterium is an increasingly recognized pathogen in THA. Cutibacterium can often present with normal serology, which may result in misdiagnosis as aseptic THA failure. Without the administration of postoperative antibiotics after positive cultures, there is a risk for persistent infection requiring further surgical intervention.

Fast and Sensitive Multiplex Real-Time Quantitative PCR to Detect Cutibacterium Periprosthetic Joint Infections

Diagnosis of Cutibacterium periprosthetic joint infections (PJIs) is challenging due to a long cultivation time of up to 14 days. Faster culture-independent diagnosis would improve patient care with early and accurate treatment. Specific primers and probes were designed for Cutibacterium acnes, Cutibacterium avidum, and Cutibacterium granulosum and evaluated in a multiplex TaqMan real-time quantitative PCR (qPCR) format on 57 skin swabs and 20 culture-negative cerebrospinal fluid samples. The multiplex qPCR was tested in a PJI cohort of 41 sonication fluid samples from removed implants infected with different pathogens. All five culture-positive Cutibacterium PJIs were detected with the corresponding Cutibacterium-specific probe (100% positive percent agreement). The multiplex qPCR additionally detected C. avidum in two PJI sonication fluid samples that were diagnosed as Staphylococcus species infections according to culture (95% negative percent agreement). The new multiplex qPCR can provide a Cutibacterium PJI diagnosis within 1 day, allowing early and accurate antibiotic treatment. A prospective diagnostic trial in PJI with a high number of Cutibacterium species infections (shoulder PJI) is needed for further evaluation.

True infection or contamination in patients with positive Cutibacterium blood cultures-a retrospective cohort study

Cutibacterium is a genus often considered a contaminant when present in blood cultures, but it can also cause severe infections, especially related to implanted foreign materials. We investigated the incidence and features of patients with true Cutibacterium infection. Patients with positive Cutibacterium blood cultures between the years 2015-2020 in southern Sweden were identified through microbiology records and medical records were studied retrospectively. Cutibacterium isolates were species determined using MALDI-TOF MS. Patients were classified as having true infection or contamination according to a definition considering both clinical and microbiological features and these groups were compared. A total of 313 episodes of positive Cutibacterium blood cultures were identified in 312 patients. Of these, 49 (16%, corresponding to an incidence of 6 cases per million inhabitants per year) were classified as true infections. The most common species was Cutibacterium acnes (87%), and the majority were elderly men with comorbidities. Patients with true Cutibacterium infection often had an unknown focus of infection (n = 21) or a focus in the respiratory tract (n = 18). We identified one episode of ventriculo-peritoneal shunt infection, three episodes of aortic stent-graft infection, and one episode of infective endocarditis. Two patients, where Cutibacterium was isolated at the site of infection, had only one positive blood culture. The finding of positive Cutibacterium blood cultures should not always be considered contamination. Definitions of true Cutibacterium bacteremia with a demand that more than one blood culture must be positive may miss true infections.

Differential microbiological spectrum and resistance pattern in periprosthetic hip joint infections: a matched-cohort analysis comparing direct anterior versus lateral approach

BACKGROUND

In recent years, total hip arthroplasty via the direct anterior approach (DAA) has become more common. Little is known on the influence of the surgical approach on the microbiological spectrum and resistance pattern in periprosthetic hip joint infections. The aim of the present study was to evaluate the microbiological spectrum and resistance pattern in periprosthetic hip joint infections comparing the direct anterior versus lateral approach in a matched-cohort analysis at a single institution.

METHODS

Patients who underwent revision hip arthroplasty due to PJI following primary total hip arthroplasty with culture positive microbiology were analyzed. In all study patients, both the primary surgery and the revisions surgery were performed at the same institution. Only patients in whom primary surgery was performed via a direct anterior or lateral approach were included (n = 87). A matched cohort analysis was performed to compare the microbiological spectrum and resistance pattern in PJI following direct anterior (n = 36) versus lateral (n = 36) primary THA.

RESULTS

We identified both a significantly different microbiological spectrum and resistance pattern in PJI comparing direct anterior versus lateral approach THA. Cutibacterium avidum was obtained more frequently in the anterior subgroup (22.2% vs. 2.8%, p = 0.028). In the subgroup of infections with Staphylococcus aureus (n = 12), methicillin resistance was detected in 3/5 cases in the direct anterior group versus 0/7 cases in the lateral group (p = 0.045). Overall, Staphylococcus epidermidis was the most common causative microorganism in both groups (direct anterior: 36.1%; lateral: 27.8%, p = 0.448).

CONCLUSION

The present study indicates a potential influence of the localization of the skin incision in THA on the microbiological spectrum and resistance pattern in PJI. Cutibacterium avidum seemed to be a more common causative microorganism in PJI in patients who underwent direct anterior compared to lateral approach THA.

Multidrug-resistant Cutibacterium avidum isolated from patients with acne vulgaris and other infections

OBJECTIVES

Cutibacterium avidum, a human skin bacterium, rarely causes infectious diseases. It has been recently shown that C. acnes, another member of the genus Cutibacterium, acts as an opportunistic pathogen in surgical site infections. However, the antimicrobial susceptibility and pathogenicity of C. avidum remain unknown. Here, we investigated the epidemiological features of C. avidum.

RESULTS

C. avidum strains were isolated from patients with acne vulgaris (29 strains) and patients with other infections (12 strains). Antimicrobial susceptibility testing showed clarithromycin and clindamycin resistance in 65.9% of the tested strains (27/41). In addition, ciprofloxacin resistance was found in 34.1% of the strains (14/41), and 13 of those strains additionally exhibited resistance to both macrolides and clindamycin. Notably, the macrolides-clindamycin resistance gene erm(X) was found on the chromosomes of 92.6% (25/27) of the clindamycin-resistant strains and may be prevalent owing to transmission among C. avidum strains. Ciprofloxacin-resistant strains developed amino acid substitutions in GyrA owing to the use of antimicrobial agents. Pulsed-field gel electrophoresis (PFGE) analysis revealed that only a few strains exhibited 100% similarity. Additionally, no clustering associated with antimicrobial resistance, biofilm-forming ability, and type of infection was observed.

CONCLUSIONS

Our study revealed that erm(X) may be frequently disseminated in C. avidum, and multidrug-resistant C. avidum strains may colonize the skin of patients with acne vulgaris and patients with other infections. Therefore, the prevalence of multidrug-resistant C. avidum and the use of antimicrobial agents for the treatment of acne vulgaris and other infections associated with C. avidum should be monitored.

Simultaneous Propionibacterium avidum and Propionibacterium acnes Chronic Periprosthetic Hip Joint Infection: A Case Report

Prosthetic hip joint replacement is considered the operation of the 20th century because of its wide diffusion and good outcome. More than 1 million prostheses are implanted worldwide annually. Although hip arthroplasty is considered a safe procedure, different complications can occur in relation with surgery. Periprosthesic joint infection is the most feared for its morbidity for the patients, and for the economic costs it generates. Most surgical site infections after hip arthroplasty are related to frequent germs as Staphylococci or Enterobacteriaceae, while Propionibacterium infections are more rare and often challenging in diagnosis and therapy. We report a case of a 77-year-old diabetic overweight male patient who developed a periprosthetic hip infection due to P. avidum and P. acnes after a mini-invasive direct anterior approach. To our knowledge, this represents the first case of chronic periprosthetic hip joint co-infection.

The role of biofilm formation in the pathogenesis and antimicrobial susceptibility of Cutibacterium acnes

Cutibacterium acnes (previously known as Propionibacterium acnes) is frequently found on lipid-rich parts of the human skin. While C. acnes is most known for its role in the development and progression of the skin disease acne, it is also involved in many other types of infections, often involving implanted medical devices. C. acnes readily forms biofilms in vitro and there is growing evidence that biofilm formation by this Gram-positive, facultative anaerobic micro-organism plays an important role in vivo and is also involved in treatment failure. In this brief review we present an overview on what is known about C. acnes biofilms (including their role in pathogenesis and reduced susceptibility to antibiotics), discuss model systems that can be used to study these biofilms in vitro and in vivo and give an overview of interspecies interactions occurring in polymicrobial communities containing C. acnes.

Diagnosis of orthopaedic-implant-associated infections caused by slow-growing Gram-positive anaerobic bacteria - a clinical perspective

Slow-growing Gram-positive anaerobic bacteria (SGAB) such as Cutibacterium acnes are increasingly recognized as causative agents of implant-associated infections (IAIs) in orthopaedic surgeries. SGAB IAIs are difficult to diagnose because of their non-specific clinical and laboratory findings as well as the fastidious growth conditions required by these bacteria. A high degree of clinical suspicion and awareness of the various available diagnostic methods is therefore important. This review gives an overview of the current knowledge regarding SGAB IAI, providing details about clinical features and available diagnostic methodologies. In recent years, new methods for the diagnosis of IAI were developed, but there is limited knowledge about their usefulness in SGAB IAI. Further studies are required to determine the ideal diagnostic methodology to identify these infections so that they are not overlooked and mistakenly classified as aseptic failure.

The Impact of Surgical Strategy and Rifampin on Treatment Outcome in Cutibacterium Periprosthetic Joint Infections

BACKGROUND

Cutibacterium species are common pathogens in periprosthetic joint infections (PJI). These infections are often treated with β-lactams or clindamycin as monotherapy, or in combination with rifampin. Clinical evidence supporting the value of adding rifampin for treatment of Cutibacterium PJI is lacking.

METHODS

In this multicenter retrospective study, we evaluated patients with Cutibacterium PJI and a minimal follow-up of 12 months. The primary endpoint was clinical success, defined by the absence of infection relapse or new infection. We used Fisher's exact tests and Cox proportional hazards models to analyze the effect of rifampin and other factors on clinical success after PJI.

RESULTS

We included 187 patients (72.2% male, median age 67 years) with a median follow-up of 36 months. The surgical intervention was a 2-stage exchange in 95 (50.8%), 1-stage exchange in 51 (27.3%), debridement and implant retention (DAIR) in 34 (18.2%), and explantation without reimplantation in 7 (3.7%) patients. Rifampin was included in the antibiotic regimen in 81 (43.3%) cases. Infection relapse occurred in 28 (15.0%), and new infection in 13 (7.0%) cases. In the time-to-event analysis, DAIR (adjusted hazard ratio [HR] = 2.15, P = .03) and antibiotic treatment over 6 weeks (adjusted HR = 0.29, P = .0002) significantly influenced treatment failure. We observed a tentative evidence for a beneficial effect of adding rifampin to the antibiotic treatment-though not statistically significant for treatment failure (adjusted HR = 0.5, P = .07) and not for relapses (adjusted HR = 0.5, P = .10).

CONCLUSIONS

We conclude that a rifampin combination is not markedly superior in Cutibacterium PJI, but a dedicated prospective multicenter study is needed.

Cutibacterium avidum resists surgical skin antisepsis in the groin-a potential risk factor for periprosthetic joint infection: a quality control study

BACKGROUND

The skin commensal Cutibacterium avidum has been recognized as an emerging pathogen for periprosthetic joint infections (PJI). One currently assumes that the early occurring PJIs are a consequence of skin commensals contaminating the peri-implant tissue during surgery. We addressed whether standard skin antisepsis with povidone-iodine/alcohol before total hip arthroplasty (THA) is effective to eliminate colonizing bacteria with focus on C. avidum.

METHODS

In a single-center, prospective study, we screened all patients for skin colonizing C. avidum in the groin before THA. Only in the patients positive for C. avidum, we preoperatively repeated skin swabs after the first and third skin antisepsis and antibiotic prophylaxis. We also obtained dermis biopsies for microbiology and fluorescence in situ hybridization (FISH).

RESULTS

Fifty-one out of 60 patients (85%) were colonized on the skin with various bacteria, in particular with C. avidum in 12 out of 60. Skin antisepsis eliminated C. avidum in eight of ten (20%) colonized patients undergoing THA. Deeper skin (dermis) biopsies were all culture negative, but FISH detected single positive ribosome-rich C. avidum in one case near sweat glands.

CONCLUSION

Standard skin antisepsis was not effective to completely eliminate colonizing C. avidum on the skin in the groin of patients undergoing THA. Colonizing with C. avidum might pose an increased risk for PJI when considering a THA. Novel more effective antisepsis strategies are needed. Trial registration No clinical trial.

Revealing antimicrobial resistance in stormwater with MinION

Discharge of urban stormwater containing organic matter, heavy metals and sometime human feces, to the natural aquatic reservoirs without any treatment is not only an environmental problem. It can lead to prevalence of antibiotic resistant bacteria in stormwater systems and transmission of antibiotic resistance genes to the environment. We performed antibiotic resistome identification and virus detection in stormwater samples from Stockholm, using publicly available metagenomic sequencing MinION data. A MinION platform offers low-cost, precise environmental metagenomics analysis. 37 groups of antibiotic resistant bacteria (ARB), 11 resistance types with 26 resistance mechanisms - antibiotic resistance genes (ARGs) giving tolerance to the aminoglycoside, beta-lactams, fosmidomycin, MLS, multidrug and vancomycin were identified using ARGpore pipeline. The majority of the identified bacteria species were related to the natural environment such as soil and were not dangerous to human. Alarmingly, human pathogenic bacteria carrying resistance to antibiotics currently used against them (Bordetella resistant to macrolides and multidrug resistant Propionibacterium avidum) were also found in the samples. Most abundant viruses identified belonged to Caudovirales and Herpesvirales and they were not carrying ARGs. Unlike the virome, resistome and ARB were not unique for stormwater sampling points. This results underline the need for extensive monitoring of the microbial community structure in the urban stormwater systems to assess antimicrobial resistance spread.

Antimicrobial photodynamic therapy against Propionibacterium acnes biofilms using hypericin (Hypericum perforatum) photosensitizer: in vitro study

Acne vulgaris is the most recurring skin condition in the world, causing great harm to the physical and psychological well-being of many patients. Antimicrobial photodynamic therapy (aPDT) has broad therapeutic applicability. The purpose was to evaluate in vitro the photodynamic inactivation against Propionibacterium acnes (P. acnes) biofilms by using different concentrations of hypericin (Hypericum perforatum) photosensitizer associated with different energies of low-level laser. The biofilms were placed in 96-well microplates with a 6.4-mm diameter surface, by using standard suspensions (2 × 10⁷ CFU/mL) and grown in brain heart infusion broth (BHI) for 48 h in anaerobic chamber. Subsequently, the control group received application of 0.9% sterile saline solution for 3 min; the photosensitising groups received hypericin at concentrations of 5 and 15 μg/mL for 3 min; the laser groups received irradiation of energies of 3 and 5 J (660 nm, continuous output, 100 mW, 30 and 50 s and 100 J/cm² and 166 J/cm², respectively); the aPDT groups received 5 and 15 μg/mL concentrations of hypericin associated with energies of 3 and 5 J of low-level laser irradiation. After the biofilms were broken up and seeded for CFU counting. The results showed a reduction in P. acnes biofilms after aPDT emphasising that 15 μg/mL hypericin associated with 3 and 5 J laser irradiation reduced biofilms by 14.1 and 27.9%, respectively. In addition, all groups of aPDT demostrated statistically significant reductions. In vitro photodynamic inactivation against P. acnes biofilms using different concentration of hypericin photosensitizer associated with different energies of low-level laser promoted effective antimicrobial action.

Surgical Approach to Total Hip Arthroplasty Affects the Organism Profile of Early Periprosthetic Joint Infections

The optimal approach for total hip arthroplasty (THA) remains hotly debated. While wound complications following the direct anterior approach are higher than with other approaches, the organism profile of periprosthetic joint infections (PJIs) by approach remains unknown. Our goal was to compare the organism profiles of PJIs following direct anterior and non-anterior THA.

METHODS

We retrospectively reviewed 12,549 primary THAs (4,515 direct anterior and 8,034 non-anterior) that had been performed between January 2012 and September 2019 at a university-affiliated single-specialty orthopaedic hospital to identify patients with an early postoperative PJI. Criteria used for the diagnosis of a PJI were the National Healthcare Safety Network, which screens for PJI that occurs within 90 days of index arthroplasty, and the Musculoskeletal Infection Society guidelines. Patient demographic information and organism characteristics were recorded for analysis.

RESULTS

We identified 84 patients (38 who underwent the direct anterior approach and 46 who underwent the non-anterior approach) with an early postoperative PJI following primary THA (0.67% total THA PJI rate, 0.84% direct anterior THA PJI rate, and 0.57% non-anterior THA PJI rate). The direct anterior THA cohort had a significantly lower body mass index and American Society of Anesthesiologists score than the non-anterior THA cohort (29.5 versus 35.2 kg/m2, p < 0.0001; 2.29 versus 2.63, p = 0.016, respectively). Regarding organism profile, patients in the direct anterior THA cohort had significantly more monomicrobial gram-negative infections than the non-anterior THA cohort (4 versus 0, p = 0.038). We did not identify any demographic risk factors other than approach for gram-negative PJI. There were no significant differences in methicillin-resistant Staphylococcus aureus, methicillin-sensitive Staphylococcus aureus, coagulase-negative Staphylococcus, obligate anaerobes, polymicrobial, or PJIs due to other organisms by approach.

CONCLUSIONS

Direct anterior THA approaches have a greater risk of monomicrobial gram-negative PJI, likely due to the unique microbiome of the inguinal region. While targeted infection prophylaxis may reduce these infections, it is not entirely effective on its own. Future studies with larger sample sizes are required to help us develop more targeted perioperative infection prophylaxis.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Detecting the presence of bacteria in low-volume preoperative aspirated synovial fluid by metagenomic next-generation sequencing

OBJECTIVES

Preoperative diagnosis is important for patients who need revision surgery due to PJI. Microbial culture plays an important role in PJI diagnosis, but the sensitivity of cultures is low when the sample amount is limited or when a patient is treated with antibiotics before sample collection. In this study, metagenomic next-generation sequencing (mNGS) was used to detect bacteria in preoperative puncture synovial fluid samples from patients with suspected PJI, and the preoperative and intraoperative culture results were compared to estimate its diagnostic efficiency.

METHODS

From July 2016 to December 2018, patients with suspected PJI who underwent prosthetic joint revision surgery were included, and the results of those who had been tested by preoperative synovial fluid culture and mNGS were obtained. The demographic characteristics, medical history, laboratory test results, culture results, and mNGS results of each patient were recorded. Then, the efficiency of preoperative synovial fluid mNGS was compared to that of synovial fluid culture for diagnosing PJI.

RESULTS

A total of 37 patients were included, and 24 patients (25 joints) were diagnosed with PJI. The sensitivity, specificity, and accuracy of preoperative synovial fluid mNGS were 92%, 91.7%, and 83.7%, respectively. The sensitivity, specificity, and accuracy of preoperative synovial fluid culture were 52%, 91.7%, and 43.7%, respectively.

CONCLUSIONS

With a low volume of synovia (1 ml), mNGS can be performed with higher sensitivity and specificity compared to synovial culture. Thus, mNGS can be a useful supplemental method to improve diagnostic efficiency during the preoperative period.

Cutibacterium colonization of the anterior and lateral thigh

AIMS

Of growing concern in arthroplasty is the emergence of atypical infections, particularly Cutibacterium (formerly Propionibacterium) sp. infections. Currently, the dermal colonization rate of Cutibacterium about the hip is unknown. Therefore, the aim of this study was to investigate colonization rates of Cutibacterium sp. at locations approximating anterior and posterolateral approaches to the hip joint.

METHODS

For this non-randomized non-blinded study, 101 adult patients scheduled for hip or knee surgery were recruited. For each, four 3 mm dermal punch biopsies were collected after administration of anaesthesia, but prior to antibiotics. Prebiopsy skin preparation consisted of a standardized preoperative 2% chlorhexidine skin cleansing protocol and an additional 70% isopropyl alcohol mechanical skin scrub immediately prior to biopsy collection. Two skin samples 10 cm apart were collected from a location approximating a standard direct anterior skin incision, and two samples 10 cm apart were collected from a lateral skin incision (suitable for posterior, direct-lateral, or anterolateral approaches). Samples were cultured for two weeks using a protocol optimized for Cutibacterium.

RESULTS

A total of 23 out of 404 cultures (collected from 101 patients) were positive for a microorganism, with a total of 22 patients having a positive culture (22%). Overall, 15 of the cultures in 14 patients were positive for Cutibacterium sp. (65%), of which Cutibacterium acnes comprised the majority (n = 13; 87%). Other isolated microorganisms include coagulase-negative Staphylococcus (n = 6), Clostridium (n = 1), and Corynebacterium (n = 1). Of all positive cultures, 15 were obtained from the anterior location (65%), of which seven (60%) were from the most proximal biopsy location. However, these findings were not statistically significant (anterior vs lateral, p = 0.076; proximal vs distal, p =0.238).

CONCLUSION

Approximately 14% (14/101) of the patients demonstrated a positive Cutibacterium colonization about the hip, the majority anteriorly. Given the high colonization rate of Cutibacterium, alternative skin preparations for total hip arthroplasty should be considered. Cite this article: Bone Joint J 2020;102-B(7 Supple B):52-56.

Propionibacterium/Cutibacterium species-related positive samples, identification, clinical and resistance features: a 10-year survey in a French hospital

A 10-year retrospective study of Propionibacterium/Cutibacterium-positive samples gathered from hospitalized patients was conducted at Nantes University hospital. A total of 2728 Propionibacterium/Cutibacterium-positive samples analyzed between 2007 and 2016 were included. Due to the implementation of MALDI-TOF identification in 2013, most non-Cutibacterium acnes isolates were identified a second time using this technology. Over that period, Cutibacterium acnes remained the most predominant species accounting for 91.5% (2497/2728) of the isolates, followed by Cutibacterium avidum (4.2%, 115/2728) and Cutibacterium granulosum (2.4%, 64/2728). Regarding the origin of samples, the orthopaedic department was the main Cutibacterium sample provider representing 51.9% (1415/2728) of all samples followed by the dermatology department (11.5%, 315/2728). Samples were recovered from various tissue locations: 31.5% (858/2728) from surgery-related samples such as shoulder, spine or hip replacement devices and 19.1% (520/2728) from skin samples. MALDI-TOF method revealed misidentification before 2013. Cutibacterium avidum was falsely identified as C. granulosum (n = 33). Consequently, MALDI-TOF technology using up-to-date databases should be preferred to biochemical identification in order to avoid biased species identification. Regarding antibiotic resistance, 14.7% (20/136) of C. acnes was resistant to erythromycin. 4.1% (41/1005) of C. acnes strains, 17.9% (12/67) of C. avidum strains and 3.6% (1/28) of C. granulosum strains were found resistant to clindamycin.

Association of Cutibacterium avidum Colonization in the Groin With Obesity: A Potential Risk Factor for Hip Periprosthetic Joint Infection

Background

An increase in the incidence of hip periprosthetic joint infections caused by Cutibacterium avidum has recently been detected after hip arthroplasty with an anterior surgical approach. We raised the question of whether skin colonization with C. avidum differs between the anterior and the lateral thigh as areas of surgical incision fields.

Methods

Between February and June 2017, we analyzed skin scrapings from the groin and the anterior and lateral thigh in patients undergoing a primary hip arthroplasty. We anaerobically cultured plated swab samples for Cutibacterium spp. for ≥7 days. Univariate logistic regression analysis was used to explore associations between body mass index (BMI) and colonization rate at different sites.

Results

Twenty-one of 65 patients (32.3%) were colonized with C. avidum at any site, mainly at the groin (n = 16; 24.6%), which was significantly higher at the anterior (n = 5; 7.7%; P = .009) or lateral (n = 6; 9.2%; P = .02) thigh. Patients colonized with C. avidum did not differ from noncolonized patients in age or sex, but their BMIs were significantly higher (30.1 vs 25.6 kg/m2, respectively; P = .02). Furthermore, increased BMI was associated with colonization at the groin (odds ratio per unit BMI increase, 1.15; 95% confidence interval; 1.03-1.29; P = .01).

Conclusions

The groin, rather than the anterior thigh, showed colonization for C. avidum in obese patients. Further studies are needed to evaluate current skin disinfection and draping protocols for hip arthroplasty, particularly in obese patients.

Intra-peritoneal abscess after an abdominal hysterectomy involving Cutibacterium avidum (former Propionibacterium avidum) highly resistant to clindamycin

Cutibacterium avidum is a gram-positive anaerobic rod belonging to the cutaneous group of human bacteria with preferential colonization of sweat glands in moist areas. The microorganism rarely cause disease, generally delayed prosthetic joint infections (PJIs). We describe the second case of intraperitoneal abscess by C. avidum after an abdominal surgery in an obese female patient and the first case after a non-prosthetic abdominal surgery due to a highly clindamycin resistant strain in a patient with underling conditions. The patient was successfully treated with surgical drainage and beta-lactam antibiotics. Although rare and apparently non-pathogenic, C. avidum may be involved in infections, especially in some high-risk patients with obesity who have undergone surgical incision involving deep folder of the skin. The microorganism was identified by phenotypic methods, MALDI-TOF MS and 16S rRNA gene sequencing. Susceptibility test should be performed in C. avidum because high level resistance to clindamycin could be present. We present a literature review of C. avidum infections.

Cutibacterium avidum is phylogenetically diverse with a subpopulation being adapted to the infant gut

The infant gut harbors a diverse microbial community consisting of several taxa whose persistence depends on adaptation to the ecosystem. In healthy breast-fed infants, the gut microbiota is dominated by Bifidobacterium spp.. Cutibacterium avidum is among the initial colonizers, however, the phylogenetic relationship of infant fecal isolates to isolates from other body sites, and C. avidum carbon utilization related to the infant gut ecosystem have been little investigated. In this study, we investigated the phylogenetic and phenotypic diversity of 28 C. avidum strains, including 16 strains isolated from feces of healthy infants. We investigated the in vitro capacity of C. avidum infant isolates to degrade and consume carbon sources present in the infant gut, and metabolic interactions of C. avidum with infant associated Bifidobacterium longum subsp. infantis and Bifidobacterium bifidum. Isolates of C. avidum showed genetic heterogeneity. C. avidum consumed d- and l-lactate, glycerol, glucose, galactose, N-acetyl-d-glucosamine and maltodextrins. Alpha-galactosidase- and β-glucuronidase activity were a trait of a group of non-hemolytic strains, which were mostly isolated from infant feces. Beta-glucuronidase activity correlated with the ability to ferment glucuronic acid. Co-cultivation with B. infantis and B. bifidum enhanced C. avidum growth and production of propionate, confirming metabolic cross-feeding. This study highlights the phylogenetic and functional diversity of C. avidum, their role as secondary glycan degraders and propionate producers, and suggests adaptation of a subpopulation to the infant gut.

Cutibacterium avidum: A rare but expected agent of breast implant infection

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Cutibacterium avidum previously was considered of low pathogenicity.

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C. avidum is recognized as a causative organism of surgical site infections.

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C. avidum should not be disregarded if there are clinical signs of infection.

Cutibacterium avidum is largely commensal and part of the skin microbiota, recently recognized as a pathogen that causes surgical site infections, especially in the presence of implants or medical devices.

We present a 50-year-old woman with Cutibacterium avidum infection associated with breast implant augmentation, which required the removal of the implants to achieve the cure.

As a skin commensal, Cutibacterium avidum previously was considered of low pathogenicity, but is now recognized as a causative organism of serious spontaneous and surgical site infections. It should not be routinely disregarded without further investigation, particularly if clinical signs of infection are present.

Surgical site infections and the microbiome: An updated perspective

OBJECTIVE

To address 3 questions: What are the origins of bacteria causing surgical site infections (SSIs)? Is there evidence that the offending bacteria are present at the incision site when surgery begins? What are the estimates of the proportion of SSIs that can be prevented with perioperative control of the microbiome?

DESIGN

Review of the literature, examining recognized sources of bacteria causing surgical site infections.

METHODS

Specifically, I examined the impact of improved control of the microbiome of the skin and nares on reducing SSIs. The initial effort was to examine the reduction of SSIs linked solely to preoperative skin preparation regimens and to either topical nasal antibiotics or pre- and postoperative nasal antiseptic regimens. To corroborate the concept of the importance of the microbiome, a review of studies showing the relationship of SSIs and marker organisms (eg, Propionobacterium acnes) present at the incision sites was performed. The relationships of SSIs to the microbiome of the skin and nares were summarized.

RESULTS

Depending on key assumptions, ∼70%-95% of all SSIs arise from the microbiome of the patients' skin or nares. Data from the studies of marker organisms suggest that the infecting bacteria are present at the incision site at the time of surgery.

CONCLUSIONS

Almost all SSIs arise from the patient's microbiome. The occurrence of SSIs can be viewed as a perioperative failure to control the microbiome.

Orthopedic implant-associated infections caused by Cutibacterium spp. - A remaining diagnostic challenge

Background

The definition criteria and clinical characteristics of implant-associated infection (IAI) caused by Cutibacterium (formerly Propionibacterium) spp. are poorly known. We analyzed microbiologically proven Cutibacterium orthopedic IAI in a prospective cohort.

Methods

Patients with periprosthetic joint infections (PJI) and fixation device–associated infections (FDAI) caused by Cutibacterium spp. were prospectively included. IAI was defined by significant growth of Cutibacterium spp. and presence of at least one non-microbiological criterion for infection. The McNemar’s chi-squared or binomial test was used to compare the performance of diagnostic tests.

Results

Of 121 patients with Cutibacterium IAI, 62 patients (51%) had PJI and 59 (49%) had FDAI. 109 infections (90%) were caused by C. acnes and 12 (10%) by C. avidum. The median time from implantation until diagnosis of infection was 15.7 months (interquartile range, 5–46.5 months). Clinical local signs were present in 30 patients (28%) and radiological implant loosening in 64 patients (63%). Culture sensitivity of sonication fluid was 84%, of peri-implant tissue 84% and of synovial or peri-implant fluid 56% after 14 days of incubation.

Conclusion

Cutibacterium IAI was diagnosed late in the disease course and presented with subtle signs. Prolonged culture incubation and implant sonication improved the poor performance of conventional microbiological tests. Due to lack of reliable diagnostic tests, Cutibacterium remains difficult to detect making the diagnosis challenging.

Clinical and Biological Features of Cutibacterium (Formerly Propionibacterium) avidum, an Underrecognized Microorganism

The recent description of the genus Cutibacterium has altered the taxonomy of Propionibacterium species. These organisms still belong to the genera of the skin coryneform group, and the most-studied species remains Cutibacterium acnes. Cutibacterium avidum is also a known skin commensal. This underrecognized microorganism can, however, act as a pathogen after bacterial seeding and can be considered opportunistic, causing either superficial or deep/invasive infections. It can cause numerous infections, including but not limited to breast infections, skin abscesses, infective endocarditis, and device-related infections. The ecological niche of C. avidum is clearly different from that of other members of the genus: it is found in the axillary region or at wet sites rather than in dry, exposed areas, and the number of microorganisms increases during puberty. Historically, it has been used for its ability to modulate the immune response and for its antitumor properties. Conventional microbial culture methods and identification processes allow for its accurate identification and characterization. Thanks to the modern omics tools used for phylogenomic approaches, understanding C. avidum pathogenesis (including host-bacterium interactions and virulence factor characterization) is becoming easier, allowing for more thorough molecular characterization. These analyses have revealed that C. avidum causes diverse diseases mediated by multiple virulence factors. The recent genome approach has revealed specific genomic regions within this species that are involved in adherence and biofilm formation as well as fitness, survival, and defense functions. Numerous regions show the presence of phages and horizontal gene transfer. C. avidum remains highly sensitive to a broad spectrum of antibiotics, such as β-lactams, fluoroquinolones, macrolides, and rifampin, although erythromycin and clindamycin resistance has been described. A long-term treatment regimen with a combination of antibiotics is required to successfully eliminate the remaining adherent bacteria, particularly in the case of deep infections after debridement surgery.