Removing Cutibacterium from the Skin

It is generally recognized that Cutibacterium originating from the patient's skin is the commonest organism associated with shoulder periprosthetic infections. While these organisms normally populate the skin's epidermal surface, they reside in the pilosebaceous units of the dermis - especially in the areas over the shoulder, back and face and especially in male patients. The surgical incision for shoulder arthroplasty must transect many of these structures, allowing the Cutibacterium to fall into the wound, potentially contaminating the arthroplasty.

Surgeons routinely "prep the skin" with various solutions, however the effectiveness of a skin surface prep has been shown to be suboptimal given the subsurface location this bacterial reservoir. 

Some authors have indicated that the addition of hydrogen peroxide (H2O2) may increase the effectiveness of a chlorhexidine gluconate (CHG) prep (which is the most common solution applied before shoulder arthroplasty).

The authors of Does adding hydrogen peroxide to chlorhexidine gluconate increase the effectiveness of skin preparation in reducing cutaneous Cutibacterium levels? A randomized controlled trial studied eighteen male volunteers; the two shoulders of each volunteer were randomized to receive either (A) the control preparation - 2% CHG in 70% isopropyl alcohol alone (CHG) or (B) 3% H2O2 followed by 2% CHG in 70% isopropyl alcohol (H2O2!CHG). 

Skin swabs were taken from each shoulder prior to skin preparation and again at 60 minutes after preparation. Swabs were cultured for Cutibacterium and observed for 14 days. Cutibacterium skin load was reported using a semiquantitative system based on the number of quadrants growing on the culture plate, thus the range for the Specimen Cutibacterium Value (SpCuV) is 0 to 4. This is an example of a 4, all four quadrants have growth.

Prior to skin preparation, 100% of the CHG-only shoulders and 100% of the H2O2!CHG shoulders had positive skin surface cultures for Cutibacterium. 

The mean SpCuV for the CHG-only shoulders prior to preparation was 2.1 +/- 0.8.
The mean baseline SpCuV for the H2O2!CHG shoulders prior to preparation  was 2.2 +/- 0.7.

The mean SpCuV for the CHG-only shoulders 60 minutes after preparation was 1.3 +/- 0.9.
The mean SpCuV for the H2O2!CHG shoulders 60 minutes after preparation was 1.4 +/- 0.9 

There was a reduction of Cutibacterium load at 60 minutes in 10 (56%) of the CHG-only shoulders.
There was a reduction of Cutibacterium load at 60 minutes in 11 (61%) of the H2O2!CHG shoulders.

The mean reduction in SpCuV at 60 minutes was 0.8 for the CHG-only group
The mean reduction in SpCuV at 60 minutes was 0.8 for the H2O2!CHG group.

After 60 minutes, Cutibacterium had repopulated the skin surface on 14 (78%) of the CHG-only shoulders.
After 60 minutes, Cutibacterium had repopulated the skin surface on 14 (78%) of the H2O2!CHG shoulders.

Comment: These data corroborate other studies indicating that Cutibacterium cannot be removed from the skin by skin preparation of the shoulder. 

While skin surface preparations may be of some value in temporarily reducing the load of these organisms, a combination of host defenses along with intraoperative and postoperative prophylactic measures must be relied on to defend the shoulder against periprosthetic infection.

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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link). 

Predicting infection risk in shoulder arthroplasty

Cutaneous microbiology of patients having primary shoulder arthroplasty

These authors point out that shoulder periprosthetic infections are predominantly caused by bacteria residing in the skin of healthy individuals.

They tested the hypothesis that easy-to-obtain preoperative characteristics were significantly associated with the cutaneous microbiology and the loads of specific bacteria in shoulders having joint replacement.

They identified the microbiology of the unprepared epidermal skin surface and of the dermal edge freshly incised at surgery in 332 patients having primary shoulder arthroplasty.

The load of bacteria in each sample was characterized as a value based on the laboratory report: 0 for “no growth”; 0.1 for “one colony only” or for “broth only”; and 1, 2, 3, and 4 for 1+, 2+, 3+, and 4+ growth, respectively.

Cultures of the unprepared epidermal skin surface showed positive results for a wide variety of organisms, including Cutibacterium in 72%, coagulase-negative Staphylococcus in 61%, and a spectrum of other organisms in 32%.

By contrast, cultures of the freshly incised dermal edge showed a great preponderance of Cutibacterium (34%) in comparison to low levels of coagulase-negative Staphylococcus (8%) and other organisms (2%).

An increased dermal load of Cutibacterium was significantly associated with male sex (p<.001), younger patient age (p<.001), American Society of Anesthesiologists class 1 (p 0.046), use of testosterone supplements (p 0.014), prior shoulder surgery (p 0.046, and higher Cutibacterium loads on the unprepared skin surface (p<.001)

They concluded that although the microbiology of the unprepared skin surface is diverse, the same is not true for the freshly incised dermis, where Cutibacterium is the predominant organism.

Readily available preoperative patient characteristics were significantly associated with the load of Cutibacterium in the incised dermis.

Preoperative cultures of the unprepared skin surface appear to be a new method for predicting the type and load of bacteria found in the freshly incised dermis at the time of surgery.

Comment:  Knowledge of the preoperative characteristics of patients likely to have high dermal loads of Cutibacterium may help identify those for whom extraordinary means of prophylaxis (such as Betadine lavage, in-wound topical antibiotics, extended postoperative antibiotics) may be indicated to reduce the risk of periprosthetic infection.

The relationship of male sex, young age, good health, and testosterone supplements to the dermal load of Cutibacterium is consistent with previous observations that higher levels of male sex hormones are associated with increased sebum production in dermal pilosebaceous units and a commensurate increase in the number of Cutibacterium in these dermal structures.

It is of interest that the risk factors for higher loads of Cutibacterium in the dermal incisions for elective shoulder arthroplasty are quite different from the risk factors characteristically associated with periprosthetic infections of the hip and knee, which include older age, female sex, diabetes, high ASA score, obesity, and Medicaid insurance coverage.

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How you can support research in shoulder surgery Click on this link.

We have a new set of shoulder youtubes about the shoulder, check them out at this link.

Be sure to visit "Ream and Run - the state of the art"  regarding this radically conservative approach to shoulder arthritis at this link and this link

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages   arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Shoulder joint replacement - does hydrogen peroxide reduce Cutibacterium risk?

Hydrogen peroxide skin preparation reduces Cutibacterium acnes in shoulder arthroplasty: a prospective, blinded, controlled trial

These authors sought to determine whether preoperative skin preparation with hydrogen peroxide reduces intraoperative culture positivity for Cutibacterium acnes in shoulder arthroplasty.

They included a consecutive series of patients scheduled to undergo primary anatomic or reverse total shoulder arthroplasty. First, for both cohorts, they wiped the skin with 70% ethyl alcohol and then prepared the skin with ChloraPrep. In the control group, they did not perform any further skin preparation. In the peroxide group, they wiped the skin with 3% hydrogen peroxide between the alcohol and ChloraPrep steps. In all cases, they applied an occlusive, adherent, iodine-impregnated drape after the prep.

After incision, they took aerobic and anaerobic cultures using swabs. First, they lifted the adherent dressing from the skin, and took 1 culture from the surface of the skin. Second, they took 1 culture from the incision edge along the dermis. Third, they took 1 culture from the humeral articular surface. Fourth, they waved 1 culture in the air as a negative control. 

There were fewer patients within the peroxide group with triple-positive cultures (skin, dermis, and joint) (0% vs. 19%, P . .024) and positive cultures from the joint (10% vs. 35%, P . .031).

 The vast majority of positive cultures were for C. acnes.

The differences were only significant in males. 

Comment: This was a very carefully done study, but it raises some important questions:
(1) How do we interpret the observation that in primary male arthroplasties 44% of the humeral head cultures were positive? Were these bacteria in place before the incision, or were they contaminated by blood from the incised dermis (which was culture positive in 50%)?
(2) How do we incorporate the finding that one in seven of the air cultures were positive? Is this evidence of unsterile air in the OR or does it raise the possibility of specimen contamination during handling?
(3) In that the hydrogen peroxide was applied to the skin surface, why was there no difference in skin culture positivity between the treated and untreated skin (31% vs 31%)?
(4) Of the three culture sites (skin, dermis and joint), why was the joint - the furthest site from the application of hydrogen peroxide -  the only site to show a significant reduction in the rate of culture positivity?
(5) Since the "wipe" of hydrogen peroxide application was followed immediately by the application of ChloraPrep, was there enough time for the hydrogen peroxide to penetrate the skin?

This study can be compared to that posted below
Preoperative Skin-Surface Cultures Can Help to Predict the Presence of Propionibacterium in Shoulder Arthroplasty Wounds 

Propionibacterium species are commonly cultured from specimens harvested at the time of revision shoulder arthroplasty. These bacteria reside in normal sebaceous glands, out of reach of surgical skin preparation. The arthroplasty incision transects these structures, which allows Propionibacterium to inoculate the wound and to potentially lead to the formation of a biofilm on the inserted implant. To help identify patients who are at increased risk for wound inoculation, these authors investigated whether preoperative cultures of the specimens from the unprepared skin surface were predictive of the results of intraoperative cultures of dermal wound-edge specimens obtained immediately after incision of the surgically prepared skin.

Sixty-six patients (mean age, 66.1 ± 9.4 years [range, 37 to 82 years]; 73% male) undergoing primary shoulder arthroplasty had preoperative cultures of the unprepared skin surface and intraoperative cultures of the freshly incised dermis using special culture swabs.

For the first 50 patients, a control swab was opened to air during the same time that the dermal specimen was obtained.

The results for female and male patients were characterized as the Specimen Propionibacterium Value (SpPV). The authors then determined the degree to which the results of cultures of the skin surface specimens were predictive of the results of culture of the dermal specimens.

An example of this semiquantitative reporting is shown below for the 21-day cultures of specimens from a 42-year-old man who presented for a primary shoulder arthroplasty.
Fig. 1-A Results of the culture of a specimen from the unprepared skin surface. Combining the culture positivity for the 2 different species of Propionibacterium yielded an SpPV of 2.
Note that, despite the presence of these bacteria, the Gram smear was negative.
Fig. 1-B Results of the culture of a specimen from the freshly incised dermis. The SpPV was 3.
Fig. 1-C Results of the culture of the control swab. TheSpPVwas 0.

Results: The skin-surface SpPV was greater than 1 in 3 (17%) of the 18 female patients and in 34 (71%) of the 48 male patients (p <0.001).

The dermal SpPV was greater than 1 in 0 (0%) of the 18 female patients and in 19 (40%) of the 48 male patients (p < 0.001).

None of the control samples had an SpPV greater than 1.   The predictive characteristics of a skin-surface SpPV of greater than 1 for a dermal SpPV of greater than 1 were as follows: sensitivity, 1.00 (95% confidence interval [CI], 0.82 to 1.00); specificity, 0.62 (95% CI, 0.46 to 0.75); positive predictive value, 0.51 (95% CI, 0.34 to 0.68); and negative predictive value, 1.00 (95% CI, 0.88 to 1.00).

The authors concluded that preoperative culture of the unprepared skin surface can help to predict whether the freshly incised dermal edge is likely to be positive for Propionibacterium. This test may help to identify patients who may merit more aggressive topical and systemic antibiotic prophylaxis.

They also point out the value of semiquantitative culture reported in understanding the significance of culture results.

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We have a new set of shoulder youtubes about the shoulder, check them out at this link.

Be sure to visit "Ream and Run - the state of the art" regarding this radically conservative approach to shoulder arthritis at this link and this link

Use the "Search" box to the right to find other topics of interest to you.

How you can support progress in shoulder surgery

You may be interested in some of our most visited web pages arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Predicting the presence of Propionibacterium in the freshly incised dermis In primary shoulder arthroplasty.

Preoperative Skin-Surface Cultures Can Help to Predict the Presence of Propionibacterium in Shoulder Arthroplasty Wounds 

Propionibacterium species are commonly cultured from specimens harvested at the time of revision shoulder arthroplasty. These bacteria reside in normal sebaceous glands, out of reach of surgical skin preparation. The arthroplasty incision transects these structures, which allows Propionibacterium to inoculate the wound and to potentially lead to the formation of a biofilm on the inserted implant. To help identify patients who are at increased risk for wound inoculation, these authors investigated whether preoperative cultures of the specimens from the unprepared skin surface were predictive of the results of intraoperative cultures of dermal wound-edge specimens obtained immediately after incision of the surgically prepared skin.

Sixty-six patients (mean age, 66.1 ± 9.4 years [range, 37 to 82 years]; 73% male) undergoing primary shoulder arthroplasty had preoperative cultures of the unprepared skin surface and intraoperative cultures of the freshly incised dermis using special culture swabs.

For the first 50 patients, a control swab was opened to air during the same time that the dermal specimen was obtained.

The results for female and male patients were characterized as the Specimen Propionibacterium Value (SpPV). The authors then determined the degree to which the results of cultures of the skin surface specimens were predictive of the results of culture of the dermal specimens.

An example of this semiquantitative reporting is shown below for the 21-day cultures of specimens from a 42-year-old man who presented for a primary shoulder arthroplasty.
Fig. 1-A Results of the culture of a specimen from the unprepared skin surface. Combining the culture positivity for the 2 different species of Propionibacterium yielded an SpPV of 2.
Note that, despite the presence of these bacteria, the Gram smear was negative.
Fig. 1-B Results of the culture of a specimen from the freshly incised dermis. The SpPV was 3.
Fig. 1-C Results of the culture of the control swab. TheSpPVwas 0.

Results: The skin-surface SpPV was greater than 1 in 3 (17%) of the 18 female patients and in 34 (71%) of the 48 male patients (p <0.001).

The dermal SpPV was greater than 1 in 0 (0%) of the 18 female patients and in 19 (40%) of the 48 male patients (p < 0.001).

None of the control samples had an SpPV greater than 1.   The predictive characteristics of a skin-surface SpPV of greater than 1 for a dermal SpPV of greater than 1 were as follows: sensitivity, 1.00 (95% confidence interval [CI], 0.82 to 1.00); specificity, 0.62 (95% CI, 0.46 to 0.75); positive predictive value, 0.51 (95% CI, 0.34 to 0.68); and negative predictive value, 1.00 (95% CI, 0.88 to 1.00).

The authors concluded that preoperative culture of the unprepared skin surface can help to predict whether the freshly incised dermal edge is likely to be positive for Propionibacterium. This test may help to identify patients who may merit more aggressive topical and systemic antibiotic prophylaxis.

Comment: This study shows (1) the the freshly incised dermis is often culture positive for Propionibacterium in spite of surgical skin preparation for shoulder arthroplasty,  (2) that surgeons have the opportunity to use preoperative skin cultures to determine the likelihood that the shoulder arthroplasty wound will be culture-positive for Propionibacterium, and (3) the value of taking control cultures to assess the possibility of contamination in each operating room.


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Use the "Search" box to the right to find other topics of interest to you.

Supporting progress in shoulder surgery

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Surgically prepared skin is not sterile

Preoperative Skin-Surface Cultures Can Help to Predict the Presence of Propionibacterium in Shoulder Arthroplasty Wounds

These authors point out that propionibacterium species are commonly cultured from specimens harvested at the time of revision shoulder arthroplasty. These bacteria reside in normal sebaceous glands, out of reach of surgical skin preparation. The arthroplasty incision transects these structures, which allows Propionibacterium to inoculate the wound and to potentially lead to the formation of a biofilm on the inserted implant.

To help identify patients who are at increased risk for wound inoculation, they investigated whether preoperative cultures of the specimens from the unprepared skin surface were predictive of the results of intraoperative cultures of dermal wound-edge specimens obtained immediately after incision of he surgically prepared skin.

Sixty-six patients (mean age, 66.1 ± 9.4 years [range, 37 to 82 years]; 73% male) undergoing primary shoulder arthroplasty had preoperative cultures of the unprepared skin surface and intraoperative cultures of the freshly incised dermis using special culture swabs.

For the first 50 patients, a control swab was opened to air during the same time that the dermal specimen was obtained.

The results for female and male patients were characterized as the Specimen Propionibacterium Value (SpPV) (see this link). Here are some examples of the semiquantitative laboratory reports they used in the SpPV determination.

They then determined the degree to which the results of cultures of the skin surface specimens were predictive of the results of culture of the dermal specimens.

The skin-surface SpPV was ≥ 1 in 3 (17%) of the 18 female patients and 34 (71%) of the 48 male patients (p <0.001). The dermal SpPV was  ≥ 1 in 0 (0%) of the 18 female patients and 19 (40%) of the 48 male patients (p < 0.001).

None of the control samples had an SpPV of  ≥ 1  The predictive characteristics of a skin-surface SpPV of  ≥ 1 for a dermal SpPV of  ≥ 1 were as follows: sensitivity, 1.00 (95% confidence interval [CI], 0.82 to 1.00); specificity, 0.62 (95% CI, 0.46 to 0.75); positive predictive value, 0.51 (95% CI, 0.34 to 0.68); and negative predictive value, 1.00 (95% CI, 0.88 to 1.00).

A preoperative culture of the unprepared skin surface can help to predict whether the freshly incised dermal edge is likely to be positive for Propionibacterium. This test may help to identify patients who may merit more aggressive topical and systemic antibiotic prophylaxis.

This study shows that surgeons have the opportunity to use preoperative skin cultures to determine the likelihood that the shoulder arthroplasty wound will be culture-positive for Propionibacterium.

Comment: This study is important for at least four reasons: (1) when the skin is incised for a shoulder arthroplasty, the freshly cut dermal edge is often culture positive for Propionibacterium in spite of IV antibiotics and surgical skin preparation, (2) it is important that each surgeon know his/her rate of positive control cultures to better inform the interpretation of deep wound cultures, (3) the semiquantitative results of cultures appear to be more useful than simply reporting a culture as 'positive or negative', and (4) cultures of the unprepared skin surface can be predictive of the results of cultures of the freshly incised dermis.

The results of preoperative cultures of specimens from the unprepared skin surface may be helpful for anticipating the risk of positive intraoperative dermal wound-edge cultures that may, in turn, have a bearing on the risk of prosthetic bacterial colonization. This simple test may help to identify patients who may or may not merit more aggressive topical and systemic antibiotic prophylaxis
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The reader may also be interested in these posts:

Healing through joint replacement

Supporting progress in shoulder surgery

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book.

Click here to see the new Rotator Cuff Book

Information about shoulder exercises can be found at this link.

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

See from which cities our patients come.

See the countries from which our readers come on this post.

Incising the skin is likely to introduce Propionibacterium into the surgical field

This is a repost of an important article.

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

These authors studied 50 patients undergoing open shoulder surgery after receiving 2 g intravenous cefazolin 30 minutes before the skin incision. A wide range of shoulder surgeries were included, ranging from Latarjet to reverse total shoulder to AC joint reconstruction to fracture fixation.

The first swab was termed ‘‘pre-prep.’’ This was taken from the skin surface over the intended incision site, after administration of intravenous antibiotics but before skin preparation with ChloraPrep.

The skin was then prepared with 70% alcoholic chlorhexidine.

The second swab was termed ‘‘post-prep.’’ This was taken from the skin surface over the intended incision site, after skin preparation with ChloraPrep once it was dry.

The third swab was termed ‘‘dermal swab.’’ This was taken from the exposed dermal surface within the wound immediately after the skin had been incised.

A tissue biopsy specimen was termed ‘‘dermal biopsy.’’ This was a 3-mm to 5-mm specimen taken from the dermis within the wound using a fresh blade, skin hooks, and forceps were used to harvest the specimen.

Anaerobic cultures were observed for a minimum of 14 days. Colonies were identified as P acnes by matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry.
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%).  Twelve swabs were positive for an organism other than P acnes . In the pre-prep swabs, 8 Staphylococcus epidermidis , 1 S capitis , and 2 S aureus were cultured. S capitis was also cultured in a dermal swab in a patient who was positive for P acnes.

No difference was found in the incidence of P acnes according to the surgical approach (deltopectoral, posterior, superior, or deltoid split) performed.

Dermal biopsies were positive 6 of 9 revision surgeries vs 11 of 36 primary surgeries (p =1)

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 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.

Our summary of their data is shown below.

Comment: This is an important article in that it demonstrates a high degree of correlation between positive skin surface cultures and dermal cultures carefully harvested after antibiotic prophylaxis in patients having a variety of shoulder surgeries through different open approaches. Their findings are similar to those we presented for patient having primary arthroplasty, some of which had positive deep cultures for Propionibacterium despite preoperative antibiotics and in another publication that Propionibacterium persist in the dermis of normal volunteers despite skin surface preparation.

Taken together, these findings suggest that the dermis is often not sterilized by common antibiotics and surgical preparation and that the bacteria in the opened sebaceous glands can inoculate the wound after  skin incision, injection, or arthroscopic surgery.

These data suggest that preoperative epidermal skin swabs may be a way to identify individuals at higher risk for Propionibacterium infection.

Here is an article summarizing what we think we know about Propionibacterium.

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Consultation for those who live a distance away from Seattle.

Check out the new Shoulder Arthritis Book - click here.

Click here to see the new Rotator Cuff Book

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

See from which cities our patients come.

See the countries from which our readers come on this post.

Propionibacterium - it contaminates shoulder surgery in spite of skin preparation and antibiotics

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

These authors studied 50 patients undergoing open shoulder surgery after receiving 2 g intravenous cefazolin 30 minutes before the skin incision. A wide range of shoulder surgeries were included, ranging from Latarjet to reverse total shoulder to AC joint reconstruction to fracture fixation.

The first swab was termed ‘‘pre-prep.’’ This was taken from the skin surface over the intended incision site, after administration of intravenous antibiotics but before skin preparation with ChloraPrep.

The skin was then prepared with 70% alcoholic chlorhexidine.

The second swab was termed ‘‘post-prep.’’ This was taken from the skin surface over the intended incision site, after skin preparation with ChloraPrep once it was dry.

The third swab was termed ‘‘dermal swab.’’ This was taken from the exposed dermal surface within the wound immediately after the skin had been incised.

A tissue biopsy specimen was termed ‘‘dermal biopsy.’’ This was a 3-mm to 5-mm specimen taken from the dermis within the wound using a fresh blade, skin hooks, and forceps were used to harvest the specimen.

Anaerobic cultures were observed for a minimum of 14 days. Colonies were identified as P acnes by matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry.
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%).  Twelve swabs were positive for an organism other than P acnes . In the pre-prep swabs, 8 Staphylococcus epidermidis , 1 S capitis , and 2 S aureus were cultured. S capitis was also cultured in a dermal swab in a patient who was positive for P acnes.

No difference was found in the incidence of P acnes according to the surgical approach (deltopectoral, posterior, superior, or deltoid split) performed.

Dermal biopsies were positive 6 of 9 revision surgeries vs 11 of 36 primary surgeries (p =1)

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 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.

Our summary of their data is shown below.

Comment: This is an important article in that it demonstrates a high degree of correlation between positive skin surface cultures and dermal cultures carefully harvested after antibiotic prophylaxis in patients having a variety of shoulder surgeries through different open approaches. Their findings are similar to those we presented for patient having primary arthroplasty, some of which had positive deep cultures for Propionibacterium despite preoperative antibiotics and in another publication that Propionibacterium persist in the dermis of normal volunteers despite skin surface preparation.

Taken together, these findings suggest that the dermis is often not sterilized by common antibiotics and surgical preparation and that the bacteria in the opened sebaceous glands can inoculate the wound after  skin incision, injection, or arthroscopic surgery.

These data suggest that preoperative epidermal skin swabs may be a way to identify individuals at higher risk for Propionibacterium infection.

Here is an article summarizing what we think we know about Propionibacterium.

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Consultation for those who live a distance away from Seattle.

Check out the new Shoulder Arthritis Book - click here.

Click here to see the new Rotator Cuff Book

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

See from which cities our patients come.

See the countries from which our readers come on this post.

Skin is not bacteria-free.

The microbiome extends to subepidermal compartments of normal skin.

These authors point out that commensal microbes on the skin surface influence the behaviour of cells below the epidermis. In addition they hypothesized that bacteria or their products exist below the surface epithelium and permit physical interaction between microbes and dermal cells.

They employed multiple independent detection techniques for bacteria (quantitative PCR, Gram staining, immunofluorescence and in situ hybridization) and found that bacteria were consistently detectable within the dermis and dermal adipose of normal human skin, each skin compartment having a diverse and partially distinct microbial community. 

Their data showed a high abundance of S. epidermidis in the epidermis and an abundance of Propionibacterium in the anaerobic and lipid-rich hair follicle. The two charts in Figure 4 of their article show the prevalence of these two bacteria in the hair follicles.

Comment: These data are consistent with our recent study showing that Priopionibacterium can be recovered from punch biopsies of surgically prepared skin. Since surgical incisions are likely to transect hair follicles, there is a real risk that these bacteria be introduced into the wound.

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To see the topics covered in this Blog, click here

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'