Propionibacterium persists in the skin despite standard surgical preparation

Propionibacterium acnes Has Low Susceptibility to Chlorhexidine Digluconate

BACKGROUND

The skin bacterium Propionibacterium acnes has been reported to be responsible for surgical site infections (SSIs). Skin disinfection before surgery therefore is of the utmost importance in the prevention of SSIs caused by skin bacteria.

METHODS

We assessed the susceptibility of clinical isolates of two skin bacteria, P. acnes and Staphylococcus epidermidis, to disinfectants.

RESULTS

The range of chlorhexidine digluconate (CHG) minimum inhibitory concentrations (MICs) for P. acnes isolates was 0.25-1 mcg/mL. Furthermore, the minimum bactericidal concentrations (MBCs) for a range of disinfectants were determined to evaluate their rapid bactericidal activity. The MBC range of CHG against the P. acnes isolates was 4,096->32,768 mcg/mL (MBC₈₀ 16,384 mcg/mL) after one minute of exposure and 1,024-32,768 mcg/mL (MBC₈₀ 8,192 mcg/mL) after five minutes, indicating that some strains required a CHG MBC higher than the commercial concentration of 2% (20,000 mcg/mL). In contrast, the MBCs of glutaraldehyde, sodium hypochlorite, povidone-iodine, ethanol, benzalkonium chloride, and olanexidine gluconate were all sufficiently lower than their commercial concentrations. In S. epidermidis, the MBC range of CHG was 128-1,024 mcg/mL at one minute of exposure and 4-8 mcg/mL at five minutes.

CONCLUSIONS

Different skin bacteria have different susceptibilities to disinfectants. To prevent SSIs, the selected disinfectant agent and the disinfection time should have bactericidal activity toward all the bacteria that pose a risk of infection.

Survey of shoulder arthroplasty surgeons' methods for infection avoidance of Propionibacterium

Introduction

Propionibacterium acnes infection after shoulder arthroplasty remains a source of morbidity. Determining practices amongst shoulder surgeons is the first step in developing infection-prevention best-practices.

Methods

A survey was sent to a shoulder fellowship alumni group to determine their arthroplasty infection prevention methods.

Results

74% completed the survey. Cefazolin (90%), vancomycin (50%) and clindamycin (18%) were the most commonly used antibiotics, 61% utilized more than one antibiotic. Most (76%) reported using an experience-based protocol learned during residency/fellowship.

Discussion and conclusion

There are no clear standards for prevention of Propionibacterium acnes infections in shoulder arthroplasty. There is a general non-scientific approach to the prevention of shoulder arthroplasty infection.

Preoperative skin antisepsis with chlorhexidine gluconate versus povidone-iodine: a prospective analysis of 6959 consecutive spinal surgery patients

OBJECTIVE The aim of this study was to determine the efficacy of 2 common preoperative surgical skin antiseptic agents, ChloraPrep and Betadine, in the reduction of postoperative surgical site infection (SSI) in spinal surgery procedures. METHODS Two preoperative surgical skin antiseptic agents-ChloraPrep (2% chlorhexidine gluconate and 70% isopropyl alcohol) and Betadine (7.5% povidone-iodine solution)-were prospectively compared across 2 consecutive time periods for all consecutive adult neurosurgical spine patients. The primary end point was the incidence of SSI. RESULTS A total of 6959 consecutive spinal surgery patients were identified from July 1, 2011, through August 31, 2015, with 4495 (64.6%) and 2464 (35.4%) patients treated at facilities 1 and 2, respectively. Sixty-nine (0.992%) SSIs were observed. There was no significant difference in the incidence of infection between patients prepared with Betadine (33 [1.036%] of 3185) and those prepared with ChloraPrep (36 [0.954%] of 3774; p = 0.728). Neither was there a significant difference in the incidence of infection in the patients treated at facility 1 (52 [1.157%] of 4495) versus facility 2 (17 [0.690%] of 2464; p = 0.06). Among the patients with SSI, the most common indication was degenerative disease (48 [69.6%] of 69). Fifty-one (74%) patients with SSI had undergone instrumented fusions in the index operation, and 38 (55%) patients with SSI had undergone revision surgeries. The incidence of SSI for minimally invasive and open surgery was 0.226% (2 of 885 cases) and 1.103% (67 of 6074 cases), respectively. CONCLUSIONS The choice of either ChloraPrep or Betadine for preoperative skin antisepsis in spinal surgery had no significant impact on the incidence of postoperative SSI.

Preoperative doxycycline does not decolonize Propionibacterium acnes from the skin of the shoulder: a randomized controlled trial

BACKGROUND

Propionibacterium acnes is frequently cultured in patients undergoing both primary and revision shoulder surgery. The purpose of this study was to evaluate the efficacy and safety of preoperative oral administration of doxycycline in decreasing the colonization of skin around the shoulder by P. acnes.

METHODS

This was a single-institution, prospective, randomized controlled trial of male patients undergoing shoulder arthroscopy. Patients were randomized to receive oral doxycycline (100 mg twice a day) for 7 days or to the standard of care (no drug). Before skin incision, 2 separate 3-mm punch biopsy specimens were obtained from the sites of the anterior and posterior arthroscopic portals and were sent for culture in anaerobic and aerobic medium held for 13 days.

RESULTS

There were 22 of 37 (59.5%) patients in the no-drug group and 16 of 37 (43.2%) patients in the doxycycline group who had at least 1 dermal culture positive for P. acnes (P = .245). In the no-drug group, 10 patients (45.5%) had 1 positive culture and 12 (54.5%) had 2 positive cultures (34 total positive cultures [45.9%]). In the doxycycline group, 6 (37.5%) patients had 1 positive culture and 10 (62.5%) had 2 positive cultures (26 total positive cultures [35.1%]; P = .774).

DISCUSSION

Administration of oral doxycycline for 7 days before surgery did not reduce colonization of P. acnes significantly. Given the potential risk for emergence of bacterial resistance and the adverse effects associated with administration of antibiotics, we do not recommend routine use of oral doxycycline for preoperative decolonization of the shoulder.

Utility of strain typing of Propionibacterium acnes in central nervous system and prosthetic joint infections to differentiate contamination from infection: a retrospective cohort

The study aimed to retrospectively assess if strain typing of Propionibacterium acnes could help to distinguish between infection and contamination in isolates recovered from the central nervous system (CNS) and prosthetic joints (PJs). This was a retrospective cohort of all Propionibacterium species isolates from the Barnes-Jewish Hospital (St Louis, MO, USA) clinical microbiology laboratory from 2011 to 2014. Available frozen isolates were recovered, and strain type (IA-1, IA-2, IB, II, III, or nontypeable class A or B) was determined via polymerase chain reaction (PCR)-based methods. For CNS isolates, P. acnes was considered pathogenic if treating physicians administered ≥7 days of directed antibiotic therapy against P. acnes. During the study period, Propionibacterium species was isolated from clinical cultures 411 times. 152 isolates were available for analysis. Of the 152 isolates, 140 were confirmed to be P. acnes, 61 of which were from the CNS (45 contaminants, 16 infections). Strain type IA-1 was more common (50.0%, 8 out of 16) among CNS infections than among contaminants (22.2%, 10 out of 45). For PJ isolates 61.3% (19 out of 31) met the criteria for infection. The predominant strain type for CNS infection was IA-1 and for PJ isolates, IB. Strain type IA-1 was isolated more often in patients with CNS infections, which may indicate a predilection of this strain type to cause CNS infection. Future research should prospectively evaluate strain typing as a means of assisting in the diagnosis of CNS infections and confirm our findings.

Benzoyl peroxide and clindamycin topical skin preparation decreases Propionibacterium acnes colonization in shoulder arthroscopy

BACKGROUND

Propionibacterium acnes is a gram-positive anaerobe that can lead to devastating postoperative shoulder infections. The objective of this study was to investigate whether a benzoyl peroxide and clindamycin preoperative skin preparation reduces the incidence of P. acnes colonization during shoulder arthroscopy.

METHODS

Sixty-five shoulder arthroscopy patients were prospectively enrolled. A skin culture specimen was taken at the preoperative visit from standard arthroscopic portal sites. Topical benzoyl peroxide 5% and clindamycin 1.2% (BPO/C) gel was applied to the shoulder every night before surgery. Skin culture was repeated in the operating room before preparation with chlorhexidine gluconate. Shoulder arthroscopy proceeded, with final culture specimens obtained from within the shoulder.

RESULTS

P. acnes skin colonization remained similar to prior studies at 47.7% (31 of 65 patients.) With >1 application, BPO/C was 78.9% (15 of 19 patients) effective in eliminating P. acnes superficial colonization. With 1 application, it was 66.7% (8 of 12 patients) effective in eliminating superficial colonization. Deep colonization was reduced to 3.1% (2 of 65 patients) compared with previous studies of 15% to 20% (P = .006). BPO/C was 100% effective at decreasing deep colonization with >1 application.

CONCLUSIONS

P. acnes skin colonization is high at arthroscopic shoulder portals, especially in men. Despite standard skin preparation and prophylactic antibiotics, the rate of joint inoculation is much higher than the rate of infection reported in the literature. BPO/C effectively reduces P. acnes colonization in shoulder arthroscopy. It should be considered for use before shoulder procedures with a time-related trend of >1 application.

High incidence of periprosthetic joint infection with propionibacterium acnes after the use of a stemless shoulder prosthesis with metaphyseal screw fixation - a retrospective cohort study of 241 patients

BACKGROUND

A stemless shoulder prosthesis with humeral metaphyseal screw fixation was introduced in order to save bone-stock and to facilitate reconstruction of biomechanics (Eclipse®). The aim of this study was to analyze whether the risk of infection is different with this implant compared to conventional shoulder prosthesis.

METHODS

Two hundred and forty-one patients (54.8% females) were operated with a shoulder arthroplasty and followed for median 2.0 (0.1-5.7) years. One hundred and two (42.3%) had received an Eclipse® prosthesis, the remaining patients were operated with other implants. There was an overrepresentation of males in the Eclipse® group (63.7% males) when compared with the control group (31.7% males).

RESULTS

In the Eclipse® group 10 (9.8%) patients developed a periprosthetic joint infection, as opposed to 1 (0.7%) in the control group. The most common bacteria was Propionibacterium acnes. Unadjusted infection-free survival after 4 years was 88.8% (CI 82.5-95.7) for Eclipse® patients and 95.7% (CI 87.7-100.0) for controls (p = 0.002). After adjustment for age, gender, diagnosis, and type of shoulder prosthesis (total or hemi), the risk ratio for revision due to infection was 4.3 (CI 0.5-39.1) for patients with the Eclipse® prosthesis.

CONCLUSIONS

Deep infections seem to be more common after the use of the metaphyseally fixed Eclipse® prosthesis than after conventional shoulder implants, but a predominance of male gender and younger age in the Eclipse group may have biased our findings. Future studies on larger cohorts and in vitro investigations on bacterial adherence and biofilm formation are needed.

TRIAL REGISTRATION

The study was conducted in accordance with the Helsinki Declaration. The local ethics board (Regionala Etikprövningsnämnden Stockholm) approved the study (Approval number 2015/1590-31, date of issue 2015-10-14). Retrospectively registered.

Periprosthetic shoulder infection: an overview

Periprosthetic shoulder infection (PSI) is rare but potentially devastating. The rate of PSI is increased in cases of revision procedures, reverse shoulder implants and co-morbidities. One specific type of PSI is the occurrence of low-grade infections caused by non-suppurative bacteria such as Propionibacterium acnes or Staphylococcus epidemermidis.

Success of treatment depends on micro-organism identification, appropriate surgical procedures and antibiotic administration efficiency. Post-operative early PSI can be treated with simple debridement, while chronic PSI requires a one- or two-stage revision procedure. Indication for one-time exchange is based on pre-operative identification of a causative agent. Resection arthroplasty remains an option for low-demand patients or recalcitrant infection.

Cite this article: EFORT Open Rev 2017;2:104-109. DOI: 10.1302/2058-5241.2.160023

Propionibacterium acnes biofilm is present in intervertebral discs of patients undergoing microdiscectomy

Background

In previous studies, Propionibacterium acnes was cultured from intervertebral disc tissue of ~25% of patients undergoing microdiscectomy, suggesting a possible link between chronic bacterial infection and disc degeneration. However, given the prominence of P. acnes as a skin commensal, such analyses often struggled to exclude the alternate possibility that these organisms represent perioperative microbiologic contamination. This investigation seeks to validate P. acnes prevalence in resected disc cultures, while providing microscopic evidence of P. acnes biofilm in the intervertebral discs.

Methods

Specimens from 368 patients undergoing microdiscectomy for disc herniation were divided into several fragments, one being homogenized, subjected to quantitative anaerobic culture, and assessed for bacterial growth, and a second fragment frozen for additional analyses. Colonies were identified by MALDI-TOF mass spectrometry and P. acnes phylotyping was conducted by multiplex PCR. For a sub-set of specimens, bacteria localization within the disc was assessed by microscopy using confocal laser scanning and FISH.

Results

Bacteria were cultured from 162 discs (44%), including 119 cases (32.3%) with P. acnes. In 89 cases, P. acnes was cultured exclusively; in 30 cases, it was isolated in combination with other bacteria (primarily coagulase-negative Staphylococcus spp.) Among positive specimens, the median P. acnes bacterial burden was 350 CFU/g (12 - ~20,000 CFU/g). Thirty-eight P. acnes isolates were subjected to molecular sub-typing, identifying 4 of 6 defined phylogroups: IA₁, IB, IC, and II. Eight culture-positive specimens were evaluated by fluorescence microscopy and revealed P. acnes in situ. Notably, these bacteria demonstrated a biofilm distribution within the disc matrix. P. acnes bacteria were more prevalent in males than females (39% vs. 23%, p = 0.0013).

Conclusions

This study confirms that P. acnes is prevalent in herniated disc tissue. Moreover, it provides the first visual evidence of P. acnes biofilms within such specimens, consistent with infection rather than microbiologic contamination.

Prevention of Propionibacterium acnes biofilm formation in prosthetic infections in vitro

BACKGROUND

The role of Propionibacterium acnes in shoulder arthroplasty and broadly in orthopedic prosthetic infections has historically been underestimated, with biofilm formation identified as a key virulence factor attributed to invasive isolates. With an often indolent clinical course, P acnes infection can be difficult to detect and treat. This study investigates absorbable cements loaded with a broad-spectrum antibiotic combination as an effective preventive strategy to combat P acnes biofilms.

METHODS

P acnes biofilm formation on an unloaded synthetic calcium sulfate (CaSO₄) bone void filler cement bead was evaluated by scanning electron microscopy over a period of 14 days. Beads loaded with tobramycin alone or vancomycin alone (as comparative controls) and beads loaded with a vancomycin-tobramycin dual treatment were assessed for their ability to eradicate planktonic P acnes, prevent biofilm formation, and eradicate preformed biofilms using a combination of viable-cell counts, confocal microscopy, and scanning electron microscopy.

RESULTS

P acnes surface colonization and biofilm formation on unloaded CaSO₄ beads was slow. Beads loaded with antibiotics were able to kill planktonic cultures of 10⁶ colony-forming units/mL, prevent bacterial colonization, and significantly reduce biofilm formation over periods of weeks. Complete eradication of established biofilms was achieved with a contact time of 1 week.

CONCLUSIONS

This study demonstrates that antibiotic-loaded CaSO₄ beads may represent an effective antibacterial and antibiofilm strategy to combat prosthetic infections in which P acnes is involved.

Clinical impact of positive Propionibacterium acnes cultures in orthopedic surgery

BACKGROUND

The clinical significance of a positive culture to Propionibacterium acnes in orthopedic specimens remains unclear, whether about its role as a contaminant or a pathogen, or its impact as a coinfectant. Therefore, we performed a retrospective study to provide a more accurate description of the clinical impact of P. acnes in an orthopedic population aiming to determine: 1) if there is a clinical difference between P. acnes infection and contamination? 2) If there is a clinical difference between P. acnes monoinfection, and coinfection.

HYPOTHESIS

There is a clinical difference between P. acnes infection and contamination.

MATERIALS AND METHODS

Patients were selected over a five-year period, and those with a minimum of one positive culture for P. acnes, from any intraoperative orthopedic tissue sample, were included in the study. P. acnes infection was defined as the isolation of P. acnes from≥2 specimens, or in only one specimen, in the presence of typical perioperative findings and/or local signs of infection.

RESULTS

A total of 68 patients had a positive P. acnes culture, 35 of which were considered to be infected. The infections affected mostly males (29/35-83%), occurred mostly in shoulders (22/35-63%), and at a site already containing an orthopedic implant (32/35-91%). Local inflammatory signs were present in half of the cases when an infection was diagnosed. Coinfection with other pathogens was present in 31% of patients (11/35). When comparing patients coinfected with P. acnes, and those who were monoinfected, the latter presented less often with local inflammatory signs. Recurrence rate was 24% (8/35) and the only risk factor for recurrence was the presence of a monoinfection.

DISCUSSION

This study confirms the pathogenicity of P. acnes in an orthopedic population, as it is present in multiple samples in the same patient, and because it is present in cultures from cases with clinical recurrence. Our study showed that monoinfections differ from coinfections mainly by their higher risk of recurrence.

LEVEL OF EVIDENCE

Level IV retrospective case series.

Neer Award 2017: A rapid method for detecting Propionibacterium acnes in surgical biopsy specimens from the shoulder

BACKGROUND

Propionibacterium (P) acnes infection of the shoulder after arthroplasty is a common and serious complication. Current detection methods for P acnes involve anaerobic cultures that require prolonged incubation periods (typically 7-14 days). We have developed a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) approach that sensitively and specifically identifies P acnes in tissue specimens within a 24-hour period.

METHODS

Primers were designed to amplify a unique region of the 16S rRNA gene in P acnes that contained a unique HaeIII restriction enzyme site. PCR and RFLP analyses were optimized to detect P acnes DNA in in vitro cultures and in arthroscopic surgical biopsy specimens from patients with P acnes infections.

RESULTS

A 564 base-pair PCR amplicon was derived from all of the known P acnes strains. HaeIII digests of the amplicon yielded a restriction fragment pattern that was unique to P acnes. P acnes-specific amplicons were detected in as few as 10 bacterial cells and in clinical biopsy specimens of infected shoulder tissues.

CONCLUSION

This PCR-RFLP assay combines the sensitivity of PCR with the specificity of RFLP mapping to identify P acnes in surgical isolates. The assay is robust and rapid, and a P acnes-positive tissue specimen can be confirmed within 24 hours of sampling, facilitating treatment decision making, targeted antibiotic therapy, and monitoring to minimize implant failure and revision surgery.

Strains of the Propionibacterium acnes type III lineage are associated with the skin condition progressive macular hypomelanosis

Progressive macular hypomelanosis (PMH) is a common skin disorder that causes hypopigmentation in a variety of skin types. Although the underlying aetiology of this condition is unclear, there is circumstantial evidence that links the skin bacterium Propionibacterium acnes to the condition. We now describe the first detailed population genetic analysis of P. acnes isolates recovered from paired lesional and non-lesional skin of PMH patients. Our results demonstrate a strong statistical association between strains from the type III phylogenetic lineage and PMH lesions (P = 0.0019), but not those representing other phylogroups, including those associated with acne (type IA₁). We also demonstrate, based on in silico 16S rDNA analysis, that PMH isolates previously recovered from patients in Europe are also consistent with the type III lineage. Using comparative genome analysis, we identified multiple genomic regions that are specific for, or absent from, type III strains compared to other phylogroups. In the former case, these include open reading frames with putative functions in metabolism, transport and transcriptional regulation, as well as predicted proteins of unknown function. Further study of these genomic elements, along with transcriptional and functional analyses, may help to explain why type III strains are associated with PMH.

Prevalence of Propionibacterium acnes in Intervertebral Discs of Patients Undergoing Lumbar Microdiscectomy: A Prospective Cross-Sectional Study

Background

The relationship between intervertebral disc degeneration and chronic infection by Propionibacterium acnes is controversial with contradictory evidence available in the literature. Previous studies investigating these relationships were under-powered and fraught with methodical differences; moreover, they have not taken into consideration P. acnes’ ability to form biofilms or attempted to quantitate the bioburden with regard to determining bacterial counts/genome equivalents as criteria to differentiate true infection from contamination. The aim of this prospective cross-sectional study was to determine the prevalence of P. acnes in patients undergoing lumbar disc microdiscectomy.

Methods and Findings

The sample consisted of 290 adult patients undergoing lumbar microdiscectomy for symptomatic lumbar disc herniation. An intraoperative biopsy and pre-operative clinical data were taken in all cases. One biopsy fragment was homogenized and used for quantitative anaerobic culture and a second was frozen and used for real-time PCR-based quantification of P. acnes genomes. P. acnes was identified in 115 cases (40%), coagulase-negative staphylococci in 31 cases (11%) and alpha-hemolytic streptococci in 8 cases (3%). P. acnes counts ranged from 100 to 9000 CFU/ml with a median of 400 CFU/ml. The prevalence of intervertebral discs with abundant P. acnes (≥ 1x10³ CFU/ml) was 11% (39 cases). There was significant correlation between the bacterial counts obtained by culture and the number of P. acnes genomes detected by real-time PCR (r = 0.4363, p<0.0001).

Conclusions

In a large series of patients, the prevalence of discs with abundant P. acnes was 11%. We believe, disc tissue homogenization releases P. acnes from the biofilm so that they can then potentially be cultured, reducing the rate of false-negative cultures. Further, quantification study revealing significant bioburden based on both culture and real-time PCR minimize the likelihood that observed findings are due to contamination and supports the hypothesis P. acnes acts as a pathogen in these cases of degenerative disc disease.

Association Between Lumbar Disc Degeneration and Propionibacterium acnes Infection: Clinical Research and Preliminary Exploration of Animal Experiment

STUDY DESIGN

Clinical research and animal experiment.

OBJECTIVE

To investigate whether lumbar disc degeneration is associated with Propionibacterium acnes (P acnes) infection.

SUMMARY OF BACKGROUND DATA

The hypothesis that herniated discs may be infected with P acnes by way of bacteremia is remarkable. This may bring a tremendous change in treatment of lumbar disc herniation (LDH). However, this hypothesis is still controversial. Since P acnes isolated may be related to contamination.

METHODS

Nucleus pulposus from 22 patients (30 discs) with lumbar disc herniation was collected during discectomy, following aerobic and anaerobic cultures for 10 days.Twenty-four rabbits were divided into four groups. After L3-L6 being exposed, an incision was made into the three discs in groups A and B. While in groups C and D, two random segments were operated. Six weeks later, 0.05 mL of 5 × 10 CFU/mL P acnes was inoculated into operated discs in group A and sterile physiological saline in group B. In group C, 0.2 mL of 5 × 10 CFU/mL P acnes was injected through ear vein. Sterile saline was used in group D. Six weeks later, MRI was performed. Then, nucleus pulposus and paraspinal muscles were harvested for aerobic and anaerobic cultures.

RESULTS

Clinical research: Anaerobic cultures were positive in three cases: two coagulase-negative staphylococci, one particles chain bacterium. No P acnes was found. Staphylococcus epidermidis was isolated in one aerobic culture.Animal experiment: P acnes was found in 11 out of 18 (61%) discs in group A. There was no P acnes found in the other three groups.

CONCLUSION

Degenerated discs were suitable for P acnes growth. This research did not find the evidence of the symptomatic degenerated lumbar discs infected with P acnes or that P acnes could infect the degenerated lumbar discs by way of bacteremia.

LEVEL OF EVIDENCE

N/A.

Effect of surgical delay on bacterial colonization in proximal humeral fractures

Postoperative infection is a severe complication after proximal humeral fracture surgical treatment. The aim of this study was to determine if the surgical delay could modify the number and type of bacteria on the surgical site. A two stages study was set up. In the first stage the effect of delay was simulated in 20 patients affected by proximal humeral fracture treated conservatively. In a second stage, the effect of delay was measured in 20 patients that underwent surgery. In stage 1, three skin culture swabs were taken in correspondence of the deltopectoral approach, the day of the fracture (day 0), the day after (day 1), and five days after fracture (day 5). In stage 2, skin swab cultures were taken the day of trauma and immediately before surgery and cultured on various media suitable for aerobic and anaerobic bacteria. The number of bacteria increased over the course of the study, from day 0 to day 5, both considering the total number of colony-forming units and individual species of pathogen bacteria. The second stage of the study confirmed these data. An increasing number of bacteria was observed in patients that underwent surgery later than 2 days from trauma. The delay of surgery increased bacterial colonization of the skin in the deltopectoral approach area including common pathogenic bacteria such as Staphylococcus aureus, coagulase-negative staphylococci and Propionibacterium acnes. This might justify the correlation between delay to surgery and risk of infection. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:942-948, 2016.

The challenge of Propionibacterium acnes and revision shoulder arthroplasty: a review of current diagnostic options

BACKGROUND

Propionibacterium acnes is the most common cause of infection after shoulder arthroplasty. Whereas there are several methods that can aid in the diagnosis of P. acnes infection, there is not a single "gold standard" because of the difficulties inherent in identifying this bacterium. We present an evidence-based discussion of the demographic, clinical, and radiographic predictors of P. acnes infection and review the current options for diagnosis.

METHODS

This review was written after a comprehensive analysis of the current literature related to shoulder periprosthetic joint infection and P. acnes identification.

RESULTS AND CONCLUSIONS

Of the techniques reviewed, α-defensin had the highest sensitivity in detecting P. acnes infection (63%). C-reactive protein level and erythrocyte sedimentation rate were often normal in cases of infection. Whereas P. acnes can be challenging to successfully diagnose, there are several options that are considered preferable because of their higher sensitivities and specificities. The current gold standard is intraoperative culture, but major advances in molecular techniques may provide future improvements in diagnostic accuracy.

Propionibacterium acnes in shoulder surgery: is loss of hair protective for infection?

BACKGROUND

Propionibacterium acnes (P acnes) has been linked to chronic infections in shoulder surgery. It was recently observed during first-time shoulder surgery in healthy patients at a rate between 36% and 56%. Male gender and the anterolateral approach were reported risk factors. Because the skin biology greatly differs, we aimed to correlate skin complaints with P acnes-positive intraoperative cultures from different tissue layer samples in patients undergoing shoulder surgery for the first time.

METHODS

Intraoperative samples (1 skin, 1 superficial, 1 deep tissue, and 1 control sample) from 112 patients (70 men, 42 women; aged 59.2 years) were cultured. The association between the presence of P acnes in the deep or superficial tissue, or both, and 10 items of a validated preoperative questionnaire for skin pathology was explored.

RESULTS

The cultures were positive for P acnes in 38.4% (n = 43) of the cases. Skin samples were positive for P acnes in 8% (n = 9), superficial samples were positive in 23% (n = 26), and deep samples were positive in 30% (n = 34). Self-reported "loss of hair" was significantly negatively associated with the presence of P acnes in the superficial or deep tissue sample (P = .00028).

DISCUSSION

Patients who report having "loss of hair" show fewer P acnes-positive cultures in intraoperative tissue samples taken during open shoulder surgery. Whether this subgroup is at a lesser risk for P acnes infections remains to be substantiated.

LEVEL OF EVIDENCE

Basic Science Study; Microbiology.

Propionibacterium acnes in primary shoulder arthroplasty: rates of colonization, patient risk factors, and efficacy of perioperative prophylaxis

BACKGROUND

Recent literature has shown that Propionibacterium acnes can be cultured from superficial and deep layers of the shoulder. Our aims were to assess the rate of P. acnes colonization in patients undergoing primary shoulder arthroplasty, to identify patient-related risk factors, and to evaluate the efficacy of our perioperative antisepsis protocol.

METHODS

Thirty consecutive patients undergoing primary shoulder arthroplasty were included in our study. Swabs were taken perioperatively (4 superficial and 2 deep wound swabs) and analyzed quantitatively for P. acnes. Cefazolin minimum inhibitory concentration was determined for P. acnes isolates from positive deep cultures.

RESULTS

Twenty-two patients (73%) had positive cultures for P. acnes. Male gender (P = .024) and presence of hair (P = .005) had significantly higher rates of P. acnes superficial cultures. Subjects with positive superficial P. acnes cultures (P = .076) and presence of hair with a history of steroid injection (P = .092) were more likely to have deep P. acnes-positive cultures, but this was not statistically significant. Local topical antisepsis measures did not eradicate P. acnes (P = .12). Mean cefazolin minimum inhibitory concentration for P. acnes was 0.32 μg/mL.

CONCLUSION

P. acnes is commonly isolated from the skin and deep surgical wounds of patients undergoing primary total shoulder arthroplasty who have not had previous shoulder surgery. Male gender and presence of hair were significant risk factors for P. acnes colonization. Perioperative local topical antisepsis and cefazolin administration were not effective in eliminating P. acnes colonization.

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.

Frequent isolation of Propionibacterium acnes from the shoulder dermis despite skin preparation and prophylactic antibiotics

BACKGROUND

In vitro, Propionibacterium acnes (P acnes) is highly susceptible to commonly used antibiotics and antiseptics, yet in vivo, it still causes postsurgical infections of the shoulder. We hypothesized that the local environment within the pilosebaceous glands protects P acnes and that incision of the skin transects these glands, exposing viable P acnes to the wound.

METHODS

Fifty consecutive patients undergoing open shoulder surgery were prospectively studied. Prophylactic antibiotics were administered to all patients. Microbiologic swabs of the skin surface were taken before and after skin preparation with 70% alcoholic chlorhexidine. The skin was incised, and a further swab and dermal biopsy specimen were taken.

RESULTS

P acnes was cultured in 21 of 50 prepreparation skin surface swabs (42%), 7 of 50 postpreparation skin surface swabs (14%), 26 of 50 dermal swabs (52%), and 20 of 50 dermal biopsy specimens (40%). There was a significantly higher incidence of P acnes growth from the skin surface (P = .009) and dermis (P = .01) of patients aged ≤50 years old and in the dermal biopsy specimens of patients undergoing revision surgery (P = .01) and a trend toward increased incidence of P acnes in men. P acnes growth from a prepreparation skin surface swab had a sensitivity of 69%, specificity of 88%, positive predictive value of 86%, and negative predictive value of 72% at predicting subsequent P acnes growth from the dermal swab or biopsy specimen.

CONCLUSIONS

Viable P acnes persists within the skin dermis, despite standard antimicrobial precautions. These findings suggest that incising the skin is likely to lead to deep seeding of the surgical wound, which has implications for the pathogenesis and prevention of postsurgical shoulder infections.

Rapid diagnosis of Propionibacterium acnes infection in patient with hyperpyrexia after hematopoietic stem cell transplantation by next-generation sequencing: a case report

Background

The rapid determination of pathogenic agent is very important to clinician for guiding their clinical medication. However, current diagnostic methods are of limitation in many aspects, such as detecting range, time-consuming, specificity and sensitivity. In this report, we apply our new-developing pathogen detection method to clarify that Propionibacterium acnes is the causative agent of a two-year-old boy with juvenile myelomonocytic leukemia presenting clinical symptoms including serious rash and hyperpyrexia while traditional clinical methods of diagnosis fail to detect the pathogenic agent and multiple antimicrobial drugs are almost ineffective Propionibacterium acnes is confirmed to be the infectious agent by quantitative real-time polymerase chain reaction.

Case presentation

After haploidentical hematopoietic stem cell transplantation, a two-year-old boy with juvenile myelomonocytic leukemia presented to a pediatrist in a medical facility with hyperpyrexia and red skin rash which later changed to black skin rash all over his body. Traditional diagnostic assays were unrevealing, and several routine antimicrobial treatments were ineffective, including the vancomycin, meropenem, tobramycin, cefepime and rifampin. In this case, pediatrist resorted to the next-generation sequencing technology for uncovering potential pathogens so as to direct their use of specific drugs against pathogenic bacteria. Therefore, based on the BGISEQ100 (Ion Proton System) which performed sequencing-by-synthesis, with electrochemical detection of synthesis, and each such reaction coupled to its own sensor, which are in turn organized into a massively parallel sensor array on a complementary metal-oxidesemiconductor chip, we detect and identify the potential pathogens. As a result, we detected a significantly higher abundance of skin bacteria Propionibacterium acnes in patient’s blood than controls. It had been reported that patients infected by Propionibacterium acnes almost always had history of immunodeficiency, trauma or surgery. Considering this possible cause, antimicrobial treatment was adjusted to target this rare opportunistic pathogen. Fever and black skin rashes were rapidly reduced after administrating specific drugs against Propionibacterium acnes.

Conclusion

This case showed our new-developing pathogen detection method was a powerful tool in assisting clinical diagnosis and treatment. And it should be paid more attention to Propionibacterium acnes infection in clinical cases.

The effect of preheated versus room-temperature skin disinfection on bacterial colonization during pacemaker device implantation: a randomized controlled non-inferiority trial

Background

In clinical practice, patients who are awake often comment that cold surgical skin disinfectant is unpleasant. This is not only a problem of patients’ experience; heat loss during the disinfection process is a problem that can result in hypothermia. Evidence for the efficacy of preheated disinfection is scarce.

We tested whether preheated skin disinfectant was non-inferior to room-temperature skin disinfectant on reducing bacterial colonization during pacemaker implantation.

Methods

This randomized, controlled, non-inferiority trial included 220 patients allocated to skin disinfection with preheated (36 °C) or room-temperature (20 °C) chlorhexidine solution in 70 % ethanol. Cultures were obtained by swabbing at 4 time-points; 1) before skin disinfection (skin surface), 2) after skin disinfection (skin surface), 3) after the incision (subcutaneously in the wound), and 4) before suturing (subcutaneously in the wound).

Results

The absolute difference in growth between patients treated with preheated versus room-temperature skin disinfectant was zero (90 % CI −0.101 to 0.101; preheated: 30 of 105 [28.6 %] vs. room-temperature: 32 of 112 [28.6 %]). The pre-specified margin for statistical non-inferiority in the protocol was set at 10 % for the preheated disinfectant. There were no significant differences between groups regarding SSIs three month postoperatively, which occurred in 0.9 % (1 of 108) treated with preheated and 1.8 % (2 of 112) treated with room-temperature skin disinfectant.

Conclusion

Preheated skin disinfection is non-inferior to room-temperature disinfection in bacterial reduction. We therefore suggest that preheated skin disinfection become routine in clean surgery.

Trial registration

The study is registered at ClinicalTrials.gov (NCTO2260479).

Efficacy of topical benzoyl peroxide on the reduction of Propionibacterium acnes during shoulder surgery

BACKGROUND

Propionibacterium acnes infection is a significant problem after shoulder surgery. Residual P. acnes is found on the skin up to 29% of the time immediately after surgical skin preparation and in 70% of dermal biopsy specimens. These residual bacteria may be a source for infection. Identifying more ideal skin preparation may help reduce the risk of infection. The purpose of this study was to evaluate the effect that topical benzoyl peroxide (BPO), with chlorhexidine skin preparation, would have on the presence of P. acnes cultured at the time of shoulder surgery. We hypothesized that adding topical BPO to our skin preparation would reduce the number of positive P. acnes cultures identified during surgery.

METHODS

Fifty patients undergoing first-time shoulder surgery were treated with topical 5% BPO cream 48 hours before surgery. After skin preparation, 13 samples per subject were obtained. Cultures were held for 14 days.

RESULTS

Fifty patients underwent arthroscopic shoulder surgery; 650 culture specimens were obtained. The skin was positive at the initiation of surgery in 6% of cases. Tissue samples were positive in 6%. The skin was positive in 10% at the end of surgery. None of these rates of positive culture were different from the 4% rate observed with a control swab.

CONCLUSION

Application of BPO is an effective way to reduce P. acnes on skin at the beginning and, importantly, at the end of a surgical procedure. This may result in a lower risk for postoperative infection.

[Propionibacterium granulosum bare-metal stent infection after drug-eluting balloon]

INTRODUCTION

Bare-metal stents are used to treat arterial stenotic lesions. Morbidity and mortality are less important compared with other techniques. Drug-eluting balloons are often used to treat stent stenosis. We reported the case of a bare-metal stent infection after drug-eluting balloon and a review on the subject.

MATERIAL AND METHOD

Two weeks after percutaneous transluminal angioplasty with paclitaxel-eluting balloon and a bare-metal stent, our patient presented an infection of the stent. Diagnosis was based on the clinical presentation, positron emission tomography findings and isolation of Propionibacterium granulosum in repeated blood cultures. Adapted antibiotic therapy was given for three months with removal of the surgical bare-stent. Antibiotic therapy was interrupted after a second positron emission tomography. A literature search (PubMed and Cochrane) was performed on the subject.

RESULTS

We found 49 cases of peripheral bare-metal stent infection including our patient. This is a rare but serious complication with a high morbidity (25% amputation rate) and mortality (30%). It seems to be underestimated. Treatment is based on surgical ablation of the bare-metal stent and intravenous antibiotics. The role of the paclitaxel-eluting balloon is not clearly established but some authors believe that it can produce a local immunosuppression.

CONCLUSION

We report the first case of bare-metal stent infection after paclitaxel-eluting balloon. This complication is rare and difficult to diagnose. Manifestations are often limited to skin signs. Functional and vital prognosis is poor.

Propionibacterium acnes infection in shoulder arthroscopy patients with postoperative pain

BACKGROUND

Recent studies have identified Propionibacterium acnes as the causal organism in an increasing number of postoperative shoulder infections. Most reports have found a high rate of P acnes infection after open surgery, particularly shoulder arthroplasty. However, there are limited data regarding P acnes infections after shoulder arthroscopy.

MATERIALS AND METHODS

We prospectively collected data on all shoulder arthroscopies performed by the senior author from January 1, 2009, until April 1, 2013. Cultures were taken in all revision shoulder arthroscopy cases performed for pain, stiffness, or weakness. In addition, 2 cultures were taken from each of a cohort of 32 primary shoulder arthroscopy cases without concern for infection to determine the false-positive rate.

RESULTS

A total of 1,591 shoulder arthroscopies were performed during this period, 68 (4.3%) of which were revision procedures performed for pain, stiffness, or weakness. A total of 20 revision arthroscopies (29.4%) had positive culture findings, and 16 (23.5%) were positive for P acnes. In the control group, 1 patient (3.2%) had P acnes growth.

CONCLUSIONS

The rate of P acnes infection in patients undergoing revision shoulder arthroscopy is higher than previously published and should be considered in cases characterized by refractory postoperative pain and stiffness.

Propionibacterium can be isolated from deep cultures obtained at primary arthroplasty despite intravenous antimicrobial prophylaxis

BACKGROUND

Propionibacterium organisms are commonly recovered from deep cultures obtained at the time of revision arthroplasty. This study sought to determine whether deep cultures obtained at the time of primary arthroplasty can be substantially positive for Propionibacterium despite thorough skin preparation and preoperative intravenous antibiotic prophylaxis.

METHODS

After timely administration of preoperative antibiotics chosen specifically for their activity against Propionibacterium and after double skin preparation, specimens from the dermis, fascia, capsule, synovium, and glenoid tissue were sterilely harvested from 10 male patients undergoing primary shoulder arthroplasty and were submitted for culture for Propionibacterium.

RESULTS

Of the 50 specimens, 7 were positive for Propionibacterium: 3 in each of 2 patients and 1 in 1 patient. The specimen sources having positive anaerobic cultures were the dermis (1 of 10), fascia (2 of 10), synovium (1 of 10), and glenoid tissue (3 of 10). None of these patients had evidence of infection at the time of the arthroplasty.

DISCUSSION AND CONCLUSION

Preoperative antibiotics and skin preparation do not always eliminate Propionibacterium from the surgical field of primary shoulder arthroplasty. The presence of these bacteria in the arthroplasty wound may pose a risk of delayed shoulder arthroplasty failure from the subtle type of periprosthetic infection typically associated with Propionibacterium.

Dynamics of the surgical microbiota along the cardiothoracic surgery pathway

Human skin associated microbiota are increasingly described by culture-independent methods that showed an unexpected diversity with variation correlated with several pathologies. A role of microbiota disequilibrium in infection occurrence is hypothesized, particularly in surgical site infections. We study the diversities of operative site microbiota and its dynamics during surgical pathway of patients undergoing coronary-artery by-pass graft (CABG). Pre-, per-, and post-operative samples were collected from 25 patients: skin before the surgery, superficially and deeply during the intervention, and healing tissues. Bacterial diversity was assessed by DNA fingerprint using 16S rRNA gene PCR and Temporal Temperature Gel Electrophoresis (TTGE). The diversity of Operational Taxonomic Units (OTUs) at the surgical site was analyzed according to the stage of surgery. From all patients and samples, we identified 147 different OTUs belonging to the 6 phyla Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria, and Fusobacteria. High variations were observed among patients but common themes can be observed. The Firmicutes dominated quantitatively but were largely encompassed by the Proteobacteria regarding the OTUs diversity. The genera Propionibacterium and Staphylococcus predominated on the preoperative skin, whereas very diverse Proteobacteria appeared selected in peri-operative samples. The resilience in scar skin was partial with depletion in Actinobacteria and Firmicutes and increase of Gram-negative bacteria. Finally, the thoracic operative site presents an unexpected bacterial diversity, which is partially common to skin microbiota but presents particular dynamics. We described a complex bacterial community that gathers pathobionts and bacteria deemed to be environmental, opportunistic pathogens and non-pathogenic bacteria. These data stress to consider surgical microbiota as a “pathobiome” rather than a reservoir of individual potential pathogens.

The ream and run: not for every patient, every surgeon or every problem

PURPOSE

The purpose of this paper is to provide some essential and basic information concerning the ream and run technique for shoulder arthroplasty.

METHODS

In a total shoulder arthroplasty, the humeral head prosthesis articulates with a polyethylene glenoid surface placed on the bone of the glenoid. Failure of the glenoid component is recognised as the principal cause of failure of total shoulder arthroplasty. By contrast, in the ream and run procedure, the humeral head prosthesis articulates directly with the glenoid, which has been conservatively reamed to provide a stabilising concavity and maximal glenohumeral contact area for load transfer. While no interpositional material is placed on the surface of the glenoid, animal studies have demonstrated that the reamed glenoid bone forms fibrocartilage, which is firmly fixed to the reamed bony surface. Glenohumeral motion is instituted on the day of surgery and continued daily after surgery to mold the regenerating glenoid fibrocartilage. When the healing process is complete - as indicated by a good and comfortable range of motion - exercises and activities are added progressively without concern for glenoid component failure. 

RESULTS

The experience to date indicates that a technically well done ream and run procedure can restore high levels of comfort and function to carefully selected patients with osteoarthritis, capsulorrhaphy arthroplathy, and posttraumatic arthritis.

CONCLUSIONS

Patients considering the ream and run procedure should understand that this technique avoids the risks and limitations associated with a polyethylene glenoid component, but that it requires strong motivation to follow through on a rehabilitation course that may require many months. The outcome of this procedure depends on the body's regeneration of a new surface for the glenoid and requires rigorous adherence to a daily exercise program. This paper explains in detail the principal factors in patient selection and the key technical elements of the procedure. Clinical examples and outcomes are demonstrated.