The use of prophylactic antibiotics in patients undergoing dermatologic surgery has been an unclear and occasionally controversial topic. The most common settings for the use of antimicrobials in cutaneous surgery include the following:
The prevention of endocarditis
The prevention of hematogenous total joint infection
The prevention of a wound infection
The treatment of a wound infection
Currently, no large, double-blinded, randomized controlled studies have determined the risk of surgical site infections of the skin, endocarditis, or prosthetic joint infections. As such, many of the current recommendations are based on available studies and a logical approach using risk assessment. Consideration must be given, however, to the risk of using antibiotics to include allergies, emerging resistance of multiple organisms, and adverse effects.
This article briefly examines and reviews resident skin florae, the use of antibiotics for the prevention of infective endocarditis, total hematogenous joint infection, and surgical site infection, as well as discussing the treatment of postoperative wound infections of the skin.
For excellent patient education resources, see eMedicineHealth's patient education article Antibiotics.
Resident and transient bacteria populate the skin. Resident florae consist of organisms on the skin that are relatively stable in number and composition. These bacteria vary among locations on the body and among individuals. Resident bacteria live on the stratum corneum and in the outermost layers of the epidermis. Transient florae lie on the surface of the skin, are derived from exogenous sources, and vary widely.
Coagulase-negative staphylococci, such as Staphylococcus epidermidis, are the most common organisms of the normal florae. These bacteria are not common pathogens in wound infections, but they have been implicated in some cases of endocarditis. Staphylococcus aureus, which is coagulase positive, is usually not among the resident florae, but it can occasionally be found in intertriginous areas and in the nares (in 20-40% of patients). Certain cutaneous conditions, such as psoriasis and atopic dermatitis (see the images below), and the use of retinoids can be associated with high skin counts of S aureus. S aureus is frequently isolated in wound infections and rarely causes endocarditis. Streptococcus viridans is common in the oral cavity, can cause wound infections, and has been isolated in association with endocarditis.
The variety of resident bacteria also depends on location. The head, neck, and upper part of the trunk have more sebaceous glands; therefore, more lipophilic organisms, such as Propionibacterium species, are found there. Exposed areas, such as the face, neck, and hands, have higher total numbers of bacteria, including more transient bacteria such as group A streptococci. Intertriginous areas, such as the axillae and groin, can be more heavily colonized with gram-negative rods, coryneform bacteria, and S aureus. Pseudomonas aeruginosa frequently colonizes the external auditory canal and may cause infection of surgical wounds of the ear, as well as chondritis. Oral and nasal mucosa harbor a number of different organisms, most prominently S aureus, streptococci, lactobacilli, anaerobes, and corynebacteria.[1]
Additional factors such as sex, age, and occupation can affect the types of bacteria that normally reside on the skin. In addition, exposure to soaps, disinfectants, medications, and ultraviolet light can modify the types and number of bacteria on the skin. The climate affects bacterial florae because increased temperature and humidity increase bacterial counts. Although good surgical preparation can eliminate transient florae and can reduce resident florae to a minimum, complete sterilization of the skin is impossible. Approximately 20% of resident florae remain in the pilosebaceous units after antiseptic scrubbing.[2]
Infectious endocarditis (IE) is relatively uncommon, but it is associated with high morbidity and is potentially life threatening. Infectious endocarditis occurs as a result of a complex cascade of events. Turbulent blood flow due to a congenital or acquired cardiac condition may result in the formation of a nonbacterial thrombotic endocarditis (NBTE) from the deposition of fibrin and platelets on an area of endothelial damage. Bacteria introduced into the bloodstream have the potential to adhere to extracellular matrix proteins and medical devices that become coated with matrix proteins after implantation. The bacterial adherence subsequently induces the further deposition of fibrin and platelets to the affected area, resulting in the formation of a vegetation and further proliferation of bacteria.[3]
Although bacteremia may be common after many invasive procedures, only a limited number of species of bacteria commonly cause endocarditis. Streptococci, staphylococci, and enterococci make up the vast majority of infectious endocarditis pathogens. Streptococcus viridans causes at least 50% of the cases of native valve endocarditis.[4] S viridans is part of the normal oral, skin, GI, and respiratory tract florae.
Transient bacteremia is common with the manipulation of teeth and oral tissues, but true rates have varied widely amongst studies investigating the frequency of bacteremia. Transient bacteremias can also result from normal daily activities, such as brushing teeth, flossing, and chewing food. These activities of daily living contribute to a greater frequency and cumulative duration of bacteremia, with a bacterial load that is similar to those induced by dental procedures. What effect the magnitude or duration of bacteremia has is unknown, but it is surmised that the majority of infectious endocarditis cases caused by oral flora are a result of random bacteremia due to daily activities.
Other species are less often implicated in infectious endocarditis. Enterococci are part of the normal flora of the GI tract and may cause urinary tract infections. Staphylococci and streptococci are found on skin and may cause infection. The American Heart Association (AHA) guidelines recommend against antibiotic prophylaxis solely to prevent infectious endocarditis in the setting of GI or genitourinary procedures.
Please see these guidelines at Prevention of infective endocarditis: guidelines from the American Heart Association.
Patients at the highest increased lifetime risk of developing infectious endocarditis are those who have a prosthetic cardiac valve or prosthetic material used for a cardiac repair, a previous history of infective endocarditis, congenital heart disease, or a history of cardiac transplantation with the development of valvulopathy. The most recent AHA guidelines state that antibiotic prophylaxis for dental procedures is reasonable among this population, although the effectiveness of this practice is unknown. The guidelines recommend against antibiotic prophylaxis solely to prevent infectious endocarditis for GI or genitourinary procedures, even in this higher-risk population.
For procedures on infected skin, skin structures, and musculoskeletal tissue in patients with the conditions mentioned above, instituting a regimen with an antistaphylococcal penicillin or cephalosporin or vancomycin or clindamycin for those who are allergic or for those suspected of having a resistant strain of staphylococci.[3]
Few guidelines are available regarding the use of prophylactic antibiotics for the prevention of infective endocarditis in patients undergoing cutaneous surgery. The AHA has published a series of guidelines over the past 50 years regarding the administration of antibiotics to prevent infectious endocarditis in the setting of dental, genitourinary tract, or GI tract procedures, as briefly discussed above. However, these guidelines have never addressed the use of prophylactic antibiotics specific to cutaneous surgery outside of a preexisting cutaneous infection. As such, recommendations have been based on data involving the risk associated with oral, GI, and genitourinary procedures and a common-sense approach to prevention based on available data regarding infection and bacteremia rates in cutaneous surgery.
A study by Sabetta and Zitelli revealed a 2.8% incidence of transient bacteremia in patients undergoing surgery on eroded but not clinically infected skin.[5] Three other studies have revealed rates of bacteremia from 0.7-7%, but the average is approximately 1.9% when bacteremia rates among all patients in the 4 studies are evaluated.[5, 6, 7, 8] This rate is comparable to that determined among healthy individuals without infection in the course of daily activities.[9] Wright et al, in their 2008 advisory statement regarding the use of antibiotic prophylaxis in dermatologic surgery, proposed that antibiotics be used in the prevention of infectious endocarditis for any perforating procedure involving oral mucosa in high-risk patients and in low- and high-risk patients if performing a perforating procedure on infected skin.[10]
If the decision is made to provide infectious endocarditis prophylaxis, the choice of medication should be based on the surgical site and the medication restrictions of the patient. Endocarditis prophylaxis is most effective when antimicrobials are perioperatively administered in doses that result in adequate antibiotic concentrations in the serum during and after the procedure. The antibiotic should be administered 30-60 minutes before the procedure, and it should not be continued for an extended period after the procedure, in order to reduce the likelihood of microbial resistance. Currently, the AHA recommends a single preoperative dose. Postoperative doses may be given up to 2 hours after the procedure, but they should only be given if the initial preoperative dose was inadvertently not taken.
Table. Recommendations for Infective Endocarditis and Total Hematogenous Joint Infection Prophylaxis Regimens [10] (Open Table in a new window)
Surgical |
Antibiotic |
Dosage |
|
Oral |
Amoxicillin |
2 g PO |
|
or |
Cefazolin/ceftriaxone |
1 g IV/IM |
|
or |
Ampicillin |
2 g IV/IM |
|
If PCN* allergic |
Clindamycin |
600 mg PO |
|
or |
Azithromycin/clarithromycin |
500 mg PO |
|
or |
Clindamycin |
600 mg IV/IM |
|
Nonoral |
Cephalexin |
2 g PO |
|
or |
Dicloxacillin |
2 g PO |
|
or |
Cefazolin/ceftriaxone |
1 g IV/IM |
|
If PCN allergic |
Clindamycin |
600 mg PO |
|
or |
Dicloxacillin |
500 mg PO |
|
or |
Cefazolin/ceftriaxone |
1 g IV/IM |
|
or |
Clindamycin |
600 mg IV/IM |
|
*PCN - Penicillin |
Patients with prosthetic joints merit additional consideration for antibiotic prophylaxis prior to cutaneous surgery, owing to the significant and often severe implications of prothesis infection. As with infective endocarditis, currently no recommendations have been developed that specifically address antibiotic prophylaxis in the setting of dermatologic surgery on noninfected skin in patients with joint replacement.
The American Dental Association, in conjunction with the American Academy of Orthopaedic Surgeons, published an updated advisory statement regarding the use of antibiotic prophylaxis for dental procedures to prevent hematogenous total joint infection. In general, patients who have plates, pins, or screws and most of those with total joint replacements do not require prophylaxis prior to dental procedures. The group did outline a high-risk subset of patients who should receive prophylaxis prior to more extensive dental procedures likely to produce bacteremia, such as extractions, periodontal surgery, root canals, and prophylactic dental procedures (eg, cleaning) during which bleeding is anticipated. These patients include those with a history of inflammatory arthropathies, immunosuppression as a result of disease (eg, malignancy, HIV infection) or treatment of a disease, type 1 diabetes, a prior history of prosthetic joint infection, malnourishment, or hemophilia.[11, 12]
Additionally, patients who have had a procedure within the first 2 years of having undergone joint replacement should be considered high risk.[13, 14] Due to the significantly lower rates of bacteremia in the setting of a sterile procedure on noninfected skin, Hurst et al and Wright et al have proposed that antibiotic prophylaxis not be routinely required for this high-risk patient group unless the surgery involves perforation of oral mucosa in a high-risk patient, surgery on an infected site, or surgery on a noninfected site at high risk of infection.[10, 15]
Wound infections occur when an organism has the opportunity to proliferate in tissue and the body's defenses cannot combat the organism or its proliferation. Dermatologic operations are usually considered to be class 1 (ie, clean procedures) or class 2 (ie, clean-contaminated procedures), they are usually of short duration, and they are associated with a low risk of infection. The prevalence rate of postoperative wound infections in cutaneous surgery, including Mohs micrographic surgery, is estimated to be less than 5% and may be closer to 1-2%.[16] The characteristics of the patient and environmental considerations should be evaluated when assessing the risk of surgical site infections.
The following are patient risk factors:
Skin condition and location of procedure
Bacterial colonization
Obesity
Malnutrition
Advanced age
Diabetes mellitus
Renal disease
Immunosuppression
Corticosteroid use
Tobacco use
Alcohol use
Concurrent remote infection
Perioperative transfusion of blood products
The following are environmental risk factors:
Length of the operation
Design of reconstruction
Preoperative antiseptic showering and hair removal
Surgical technique
History of hospitalization prior to surgery[17]
Bacteria can be introduced into a wound at the time of surgery if sterile technique is broken, or they can be introduced through airborne transmission of desquamated skin cells, aerosolized water droplets, or dust particles.
A wound infection may be more likely in patients who have S aureus colonization due to other cutaneous conditions or in patients who are nasal carriers of S aureus. Methicillin-resistant S aureus (MRSA), both hospital and community acquired, has increased in prevalence. Questions remain about how to best address carriers of MRSA in the setting of cutaneous surgery.
A review by Trautmann et al examined 4 randomized and 7 sequential open cohort studies that evaluated the effect of nasal application of mupirocin on the rate of surgical site infections associated with S aureus, both methicillin sensitive and methicillin resistant. Of the studies evaluated, only 1 was a prospective, randomized, double-blinded study that evaluated surgical site infections in cardiosurgical patients. This study did not show any benefit for pretreatment with mupirocin. Three of 5 studies that looked at cardiac surgery patients demonstrated a significant reduction in sternotomy site infections, although they were open sequential cohort studies with variability in application regimens. No clear recommendations could be made regarding S aureus, but the authors did recommend decolonization for those patients with MRSA infection.[18]
Rao et al examined the use of mupirocin and chlorhexidine decolonization in patients carrying S aureus undergoing total joint arthroplasty. Carriers in the experimental group were instructed to apply mupirocin ointment to both nares and to bathe with chlorhexidine daily for 5 days prior to surgery. At 1-year follow-up, none of the patients (0/636) in the experimental group experienced surgical site infections, while 12 of the patients in the control group had site infections with S aureus (12/1330). The authors suggest that preoperative decolonization reduces surgical site infections in patients undergoing total joint arthroplasty.[19] Importantly, note that even with a mupirocin decontamination protocol, the rates of colonization clearance are not 100%. A double-blinded, placebo-controlled trial performed by Harbarth et al demonstrated MRSA eradication at only 44% among the treatment group.[20]
An additional concern is the emergence of strains of S aureus resistant to some of the agents used for decolonization. Resistance to mupirocin has been seen, although rates remain relatively low. Low-level resistance to chlorhexidine has also been documented. A chlorhexidine disinfectant containing alcohol may be more effective against resistant strains. Triclosan-based products are also useful, although low-level resistance has also been documented with these agents.[21] A preoperative nasal culture and prophylactic treatment of carriers of S aureus in high-risk patients undergoing cutaneous surgery may be warranted to reduce rates of postoperative infection, but, to the authors’ knowledge, this has not been investigated.
Although the infection rate in cutaneous surgery is low and infection can usually be managed successfully with good results, in certain situations antibiotics may be prescribed preoperatively to prevent wound infection. Infection rates increase with lengthy procedures and in certain body locations. Dixon et al evaluated the rates of wound infection among 2424 patients who had treatment of 5091 lesions treated with curettage, simple excision and closure, wedge excision, and removal with subsequent skin graft or flap repairs. They noted rates of infection greater than 5% in procedures performed below the knees, wedge resections of the lip or ear, skin grafts, and lesions in the groin.[22] In these circumstances, prophylactic antibiotics should be considered. The decision to prescribe prophylactic antibiotics should be based on the risk factors of the patient, the type and location of the surgery, and the risk that infection can lead to significant morbidity in that specific patient.
A retrospective analysis found that the rate of surgical site infections after extensive dermatosurgical procedures in immunocompromised patients was 6.7%. Independent risk factors for infection were bleeding after one of the surgical stages and anticoagulation with the combination of acetylsalicylic acid and a direct oral anticoagulant.[23]
If bacterial infection is present at the surgical site, or even at a distal site, the infection should be treated before an elective procedure is performed. Distant respiratory tract, urinary tract, and skin infections can seed surgical wounds. This is likely caused by infection-mediated transient bacteremia that colonizes the surgical wound.
Ideally, a prophylactic antimicrobial is orally administered 1-2 hours prior to the surgical procedure to allow tissue distribution and incorporation into the wound coagulum. Once a coagulum has formed in the wound, it is difficult for the antibiotic to penetrate and act effectively against trapped bacteria. In some clinical situations, the issue of prophylactic antibiotics may not be addressed preoperatively, but the surgeon may be concerned that the risk of infection is increased. Antibiotics are initiated immediately after surgery and continued for 3-7 days. To the authors’ knowledge, no reliable studies of an optimal duration of treatment or effectiveness of this approach are reported in the literature.
The US Centers for Disease Control and Prevention (CDC) published an updated guideline for the prevention of surgical site infections. For clean and clean-contaminated procedures, additional prophylactic antimicrobial doses are not recommended after the surgical incision is closed in the operating room, even if a drain is present.[24]
Several studies have examined the use of local antibiotics to prevent wound infection. Various formulations, including powders, ointments, pastes, antibiotic-impregnated beads, and collagen sponges, have been use in different surgical settings in hopes of lowering infection rates while reducing the potential for adverse effects associated with systemic antibiotics.[25]
The use of intraincisional antibiotics during surgery to prevent infection has been investigated. Griego and Zitelli published a report on the use of intraincisional nafcillin to prevent wound infection. Patients undergoing Mohs surgery or dermatologic surgery received a solution of nafcillin sodium in the buffered lidocaine used for local anesthesia. The authors reported an infection rate of 0.2%, compared with 2.5% in control subjects who received standard buffered lidocaine. The reported advantage of the added nafcillin is the immediate achievement of effective levels of antibiotic in the tissue, along with decreased systemic exposure to the antibiotic (thus resulting in less toxicity and possibly decreased bacterial resistance).[26] A follow-up study used intraincisional clindamycin as an alternative for penicillin-allergic patients and demonstrated similar efficacy.[27]
An additional study examined the use topical cefazolin powder in 2165 patients at the time of surgery to prevent surgical site infections. The rates of surgical site infection relative to placebo were significant (0.9% vs 4.3%, P< .001). However, when compared with systemic cefazolin, it was found to be inferior when systemic cefazolin was given preoperatively (0.9% vs 0.2%, P< .05) and not significantly different when systemic cefazolin was given postoperatively (0.9% vs 1.5%, P >.05).[28]
Postoperative infections can occur as a result of poor surgical technique. For example, an improperly designed flap or a wound closed under too much tension may lead to ischemia, which can increase the risk of infection. Similarly, excessive suture material in a wound may increase this risk. Postoperative hematoma formation and devitalized tissue from excessive cautery during surgery provide environments that promote bacterial growth.
The role of topical ointment in cutaneous surgery is to facilitate wound healing by keeping the wound moist and by increasing the removal of debris. As a result, any topical ointment (eg, petrolatum, topical antibiotic) is sufficient for postoperative use. Smack et al demonstrated an infection rate approximately equal among 922 patients randomized to using either bacitracin or white petrolatum after surgical procedures, including biopsy, electrodesiccation and curettage, excision, Mohs micrographic surgery, grafts, flaps, and dermabrasion. Advantages to the use of petrolatum are that it is inexpensive and that it is less likely to cause allergic contact dermatitis and less likely to promote bacterial antibiotic resistance. In addition, because most excisional wounds are thought to become inoculated at the time of surgery, little theoretical benefit is achieved if topical antibiotics are applied to a layered closure.[29]
Mohs surgery is considered a clean procedure rather than a sterile procedure, owing to the need to dress surgical sites while waiting for tissue confirmation of clear surgical margins. Several publications have addressed the use of antibiotics for prophylaxis against infective endocarditis and the prevention of infection in sites and situations that have been traditionally considered high risk.
Areas that have been considered to be at higher risk of infection include the nose, ears, mucosal surfaces, and below the knees. Futoryan and Grande demonstrated that in 530 Mohs procedures, the rate of wound infection is increased in patients with large defects and in those who are undergoing procedures performed on the ears.[30] Surgical situations requiring multiple stages, high-tension and flap or graft closures, extended time in surgery, or surgery of multiple sites within the same treatment session have also been considered risk factors for surgical site infections. The merit of using antibiotic prophylaxis in all of these circumstances has been called into question, and in many instances, the risks of antibiotic exposure may outweigh the benefits.
A prospective study done by Maragh et al evaluated the rate of infection of 1000 patients who had Mohs surgery of 1115 tumors, both traditional Mohs and modified Mohs surgery (slow Mohs) for lentigo maligna. None of the patients included in the study received prophylactic antibiotics. Those patients who required antibiotics for the prevention of infective endocarditis or prosthesis infection or patients who were undergoing reconstruction from an outside surgeon were excluded from participating. The rate of infection among patients who had surgery was 0.7% overall. Among all procedures that were performed on the nose within this group, the rate of infection was 1.7%. In cases in which a flap closure was performed, the rate was 2.4%. Those requiring more than one stage to clear the tumor had an overall infection rate of 0.8%.[17] This study is certainly supportive of the argument that infection rates with Mohs surgery are very low.
An individualized approach should be emphasized in determining who should receive prophylactic antibiotics, rather than a practice of prophylaxis in every case for sites that have been considered high risk, procedures that require multiple stages, or flap closures.[31]
As mentioned, Wright et al advocate the use of prophylactic antibiotics for patients who are at high risk of infection based on the surgical site or the technique used. However, they do agree that each patient requires an individualized approach, with all relevant factors considered before the decision to administer antibiotics is made.
The prescribed antimicrobial agent should be targeted toward the most likely infecting organism, usually Staphylococcus and Streptococcus species.
First-generation cephalosporins (cephalexin) and semisynthetic penicillinase-resistant penicillins (dicloxacillin) are the most commonly used prophylactic agents in skin surgery and skin infections because of their broad-spectrum coverage against most gram-positive cocci, Escherichia coli, Klebsiella species, and Proteus mirabilis. One to 2 g/d in divided doses is usually effective. In patients who are on acid-suppressive therapy for the treatment of peptic ulcer disease or reflux, consideration should be given to choosing dicloxacillin over cephalexin. A study by Madaras-Kelly et al revealed that concomitant administration of ranitidine (H2 blocker) or omeprazole (proton pump inhibitor) significantlyaffected the time of maximal concentration (tmax) and reduced the percentage of time that serum concentrations of cephalexin remained above the minimum inhibitory concentration to inhibit the growth of 90% of organisms (MIC90).[32]
Clindamycin and erythromycin are effective alternatives for S aureus coverage in patients with an allergy to penicillin. Clindamycin has excellent tissue penetration, has a broad antimicrobial spectrum, and can be useful for wounds in the oral mucosa. S aureus resistance to erythromycin has been increasing, and it has better GI tolerance because of its slow absorption.
Azithromycin, an azalide in a subclass of the macrolide antibiotics, provides good gram-positive coverage and a broad spectrum of activity against anaerobes and gram-negative bacteria. Azithromycin demonstrates cross-resistance with erythromycin-resistant gram-positive strains.
Trimethoprim-sulfamethoxazole has an identical antimicrobial spectrum to the third-generation cephalosporins, along with excellent coverage against gram-positive cocci. It may be a good agent to consider, especially in inguinal and perineal areas, but it is not effective when Pseudomonas species are a concern.
The quinolones are bactericidal antibiotics that have excellent bioavailability. The 4 generations of quinolones have increasing gram-positive coverage. Ciprofloxacin, a second-generation quinolone, has moderate S aureus effectiveness but excellent activity against pseudomonal organisms.
Vancomycin is intravenously administered and used when methicillin-resistant Staphylococcus or Enterococcus species or S epidermidis is of concern. Coagulase-negative Staphylococcus organisms are of concern in patients with recently implanted heart valves (< 60 d), and intravenous vancomycin may be needed in these patients if they undergo cutaneous surgery.
The CDC categorizes infections according to the depth of the involvement, which fall into 2 broad categories: (1) superficial (those that involve the skin and subcutaneous tissue only) and (2) deep (those that involve deeper soft tissues). Most infections associated with dermatologic procedures are categorized as superficial. See the figure below for reference.
For the purposes of standardizing the definition of a surgical site infection, the CDC devised criteria that include the following:
An infection that occurs within 30 days after the procedure
The infection involves only the skin or subcutaneous tissue of the incision
In addition, at least one of the following should be present to meet the definition[33] :
Purulent drainage from the superficial incision
Organisms isolated from an aseptically obtained culture of fluid or tissue from the superficial incision
At least one symptom of pain or tenderness, localized swelling, redness, or heat and superficial incisions deliberately opened by surgeon unless incision is culture negative and
Diagnosis of superficial incisional surgical site infection by the attending physician
Infecting organisms are often part of the resident florae of the skin or nearby mucous membranes. S aureus is most commonly isolated in cutaneous wound infections; however, E coli and Streptococcus, Pseudomonas, and Proteus species also may be responsible. Occasionally, other gram-negative organisms and Candida albicans can be isolated; these may be associated with poor hand washing and improper wound care techniques.
Inadequate postoperative wound care and poor hygiene can introduce bacteria into a wound, which can lead to infection. The clinical signs of a wound infection include edema, erythema, warmth, and purulence, which usually appear 4-8 days after a procedure. Infection should be considered when these signs are noted at the time of suture removal or if a patient calls and describes them. While some postoperative erythema and edema is not uncommon in a normally healing wound, these signs should improve with time. Worsening erythema and edema, and especially warmth with purulence, suggest infection. Reactivity to the suture material or allergic or irritant contact dermatitis due to a wound dressing or topical antibiotic can mimic these signs.
In patients with a presumed postoperative wound infection, a culture should be obtained and empiric antibiotic therapy should be initiated, with the realization that the most common organism isolated in cutaneous wound infections is S aureus. The proper technique for culturing a suspected wound infection is to roll the tip of the culture swab in a zig-zag fashion along the length of the incision after debriding any dead eschar from the wound. A first-generation cephalosporin (eg, cephalexin) or dicloxacillin provides good coverage against Staphylococcus and Streptococcus organisms. In patients with a penicillin allergy, clindamycin, azithromycin, and erythromycin are alternate choices. When culture and sensitivity results become available, the antibiotic can be changed to optimize treatment. When the presence or source of an infection is questionable, waiting for Gram stain or preliminary culture results may be advisable before therapy is started.
The prevalence of MRSA is increasing. Both healthcare-associated and community-acquired MRSA need to be considered in the context of a surgical site infection. Those at increased risk for MRSA infection include athletes, military personnel, prison inmates, men who have sex with men, intravenous drug users, homeless persons, children in daycare, Native Americans, and Pacific Islanders. Antibiotic coverage should include activity against MRSA. First-line treatment should be trimethoprim-sulfamethoxazole or a tetracycline antibiotic. Inducible lincosamide resistance is becoming more common; therefore, clindamycin should be considered a second-line agent. Fluoroquinolones also have activity against MRSA, but again, resistance is becoming more common. Intravenous antibiotic therapy should be reserved for very ill patients and may include vancomycin or linezolid.[21, 34, 35]
Pseudomonas infection of the ear must be recognized early, and therapy should be initiated upon any suggestion of infection. Pseudomonas chondritis infection manifests as a swollen, painful ear and may progress to significant morbidity if treatment is delayed or is inadequate. Oral ciprofloxacin and norfloxacin are good antimicrobial choices for treating Pseudomonas infection. Obtaining a culture of the ear is important because Staphylococcus, Streptococcus, and Proteus species may be other causative organisms and may require different antibiotic therapy.
A study by Mailler-Savage et al investigated whether levofloxacin should be used postoperatively to prevent wound infections in auricular surgical wounds allowed to heal by secondary intention. They evaluated 82 patients who had a surgical defect from removal of auricular neoplasms. Patients were randomized after surgery to a group receiving local wound care or a group receiving local wound care and a daily dose of 500 mg of levofloxacin. Complications after surgery included an inflammatory chondritis, which occurred in 10 patients (12.2%, 5 from each group) and a methicillin-sensitive S aureus infection, which occurred in 2 patients (2.4%, 1 from each group). No complications were associated with pseudomonal species in either control group.[36] This highlights the importance of considering staphylococci coverage when treating infections of the ear.
The use of antibiotics in cutaneous surgery is a subject that remains controversial. While the treatment of surgical site infections is relatively straight forward, the use of prophylactic antibiotics in cutaneous surgery remains more nebulous. The most recent evidence suggests that antibiotic prophylaxis is likely not needed in most circumstances, given the low rate of bacteremia in sterile and clean dermatologic procedures. The risks of antibiotic exposure must be carefully evaluated against the likelihood of infection and the potential associated morbidity. The decision of whether or not to use antibiotics for prophylaxis should be carefully considered and individualized to each patient's particular situation.