Development of a postoperative infection can create significant patient morbidity, most seriously sepsis. Risks for postoperative infection are varied and include patient and surgical factors (Table 3-18). Of these, the degree of wound contamination at the time of surgery plays an important role. Because most gynecologic surgeries are elective, a gynecologist has time to decrease microbial inoculum. Thus, BV, trichomoniasis, cervicitis, and active urinary tract or respiratory infections ideally are treated and eradicated prior to surgery.
TABLE 3-18Risk Factors for Postoperative Surgical Site Infection ||Download (.pdf) TABLE 3-18 Risk Factors for Postoperative Surgical Site Infection
Excessive blood loss
Lower socioeconomic status
Recent operative site surgery
Obesity (abdominal hysterectomy)
Prolonged surgical procedure (>3.5 hr)
Foreign body placement (catheter, drain, etc.)
Perioperative HbA1c>7% or CBG >250 in diabetics
Since 1964, surgical wounds have been classified according to the degree of bacterial contamination of the operative site at the time of surgery. In general, as the number of operative site bacteria (inoculum) increases, so too does the postoperative infection rate.
Clean wounds are most commonly found in procedures performed for nontraumatic indications, that are without operative site inflammation, and that avoid the respiratory, alimentary, and genitourinary tracts. No breaks occur in surgical technique. Thus, most laparoscopic and adnexal surgeries are considered to be in this category. Without prophylaxis, infection rates range from 1 to 5 percent. Prophylactic antimicrobial administration does not decrease infection rates following these procedures and is not required.
Clean contaminated wounds are those in which the respiratory, gastrointestinal, genital, or urinary tract is entered under controlled conditions, without unusual bacterial contamination. Criteria further define that there is no break in surgical technique. Infection rates range from 5 to 15 percent. This group encompasses many gynecologic procedures including total hysterectomy, cervical conization, and dilatation and curettage (D & C). Of these, hysterectomy is the gynecologic procedure most frequently followed by surgical site infection. These procedures are usually elective, and only hysterectomy and obstetric D & C require antimicrobial prophylaxis to reduce postoperative infection rates (American College of Obstetricians and Gynecologists, 2014a).
Contaminated wounds reflect operations with major breaks in sterile technique or gross GI spillage or incisions in which acute, nonpurulent inflammation is encountered (Mangram, 1999). Infection rates approximate 10 to 25 percent. For this reason, a minimum of 24 hours of perioperative antimicrobial administration is required, and delayed wound closure may be selected. Laparoscopy or laparotomy for acute salpingitis is included in this category.
Dirty wounds are typically old traumatic wounds or those that involve existing clinical infection or perforated viscera. If an abscess is present, these are considered dirty wounds. These operative sites are clinically infected at the time of surgery, and infection rates range from 30 to 100 percent. Accordingly, therapeutic antimicrobial therapy is required, and these wounds typically are allowed to close by secondary intention.
Surgical Site Infection Classification
The CDC provides definitions of hospital-acquired surgical site infections (SSIs). The Joint Commission currently is emphasizing this morbidity during their hospital accreditation process. Thus, hospitals are more attentive to infection rates and to the rates of individual surgeons.
In classifying SSIs, there are two categories, incisional and organ space (Fig. 3-13). Criteria for each category are detailed in Table 3-19. The incisional group is further subdivided into superficial and deep classes. Organ/space infections develop in spaces or organs other than that opened by the original incision or manipulated during the surgical procedure. Specific sites include the vaginal cuff, urinary tract, and intraabdominal sites. Of note, vaginal cuff infections are generally considered in the organ/space class, presuming they meet at least one of these criteria: purulent drainage from the cuff, abscess at the cuff, or pathogens cultured from fluid or tissue obtained from the cuff. Pelvic infections such as adnexal infection, pelvic abscess, or infected pelvic hematoma also fall into the category of organ/space infection.
Anatomy and classification of surgical site infections (SSI). (Modified with permission from Mangram AJ, Horan TC, Pearson ML, et al: Guideline for prevention of surgical site infection, 1999. Hospital Infection Control Practices Advisory Committee, Infect Control Hosp Epidemiol 1999 Apr;20(4):250–278.)
TABLE 3-19Criteria for Defining Surgical Site Infections (SSIs) ||Download (.pdf) TABLE 3-19 Criteria for Defining Surgical Site Infections (SSIs)
| Superficial incisional |
Involves only skin and subcutaneous tissue of the incision
Develops within 30 days of surgical procedure
Features at least one of the following:
Purulent drainage from the superficial incision
Bacteria in culture obtained aseptically from fluid or tissue from the superficial incision
Incision deliberately opened by surgeon and is culture positive (or not cultured) and patient has at least one of the following incisional signs or symptoms:
Tenderness or pain
Heat or redness
SSI diagnosis made by surgeon or attending physician
Stitch abscesses are not included in this category
Diagnosis of “cellulitis,” by itself, does not meet criterion for SSI
| Deep incisional |
Involves the deep soft tissues (muscle and fascia) of the incision
Develops within 30 days of surgical procedure
Features at least one of the following:
Purulent drainage from deep incision of surgical site (but not organ or space component)
Deep incision that spontaneously dehisces or is deliberately opened by a surgeon and is culture-positive (or not cultured) and patient has at least one of the following signs or symptoms:
Abscess or other infection found by reoperation, histopathology, or radiology
| Organ/space |
Involves any body part that was opened or manipulated during the operative procedure, excluding the skin incision, fascia, or muscle layers
Develops within 30 days of the surgical procedure
Features at least one of the following:
Purulent drainage from a drain placed through a stab wound into the organ/space
Bacteria obtained aseptically from tissue or fluid in that organ/space
Abscess found by reoperation, histopathology, or radiology
Vaginal cuff infection with purulence, abscess, and/or positive tissue or fluid culture is included in this category
For febrile morbidity, the most frequently used definition is an oral temperature of ≥38°C (≥100.4°F) on two or more occasions, 4 or more hours apart, and 24 or more hours following surgery. This condition is seen most often after hysterectomy, particularly abdominal hysterectomy; usually is not associated with other symptoms or signs of infection; and does not require antimicrobial therapy! It has been reported in up to 40 percent of women following abdominal and almost 30 percent of women after vaginal hysterectomy with antimicrobial prophylaxis. It resolves without antibiotic treatment in the absence of other symptoms or signs of infection.
A remote nonsurgical site may also serve as an origin of fever. These may include pulmonary complications, IV site phlebitis, and UTI. Thus, women who develop recurrent temperature elevation require a thorough history and a careful physical examination by the surgeon, seeking not only surgical but also nonsurgical causes (Fig. 42-2).
Operative site pain (incisional, lower abdominal, pelvic, and/or lower back) following surgery is normal. However, those with an operative site infection report increasing pain at the surgery site, and increasing tenderness is present during physical examination. With superficial SSI, pain is superficial and localized to the incision. With pelvic infection, there is deep lower abdominal and/or pelvic pain, and the most common infection sites are the parametria and the vaginal surgical margin. Pelvic abscess or infected pelvic hematoma is least common, and pain is central.
Abdominal palpation is an integral part of SSI diagnosis. Avoiding an abdominal incision if present, a surgeon slowly, gently, and deeply palpates the lower abdomen over the surgical site following hysterectomy and normally elicits patient discomfort. Tenderness does not mean an acute surgical abdomen or infection. In the immediate postoperative period, this tenderness is expected and decreases quickly. Women who develop pelvic cellulitis or cuff cellulitis will have increasing tenderness at gentle depression of the lower abdominal wall over the infected area. Tenderness may be bilateral, but more commonly is more marked on one side. Peritoneal signs are not present. Cellulitis, whether it involves the parametria, adnexa, or vaginal cuff, is not associated with a mass.
In the absence of increasing lower abdominal pain and tenderness, a bimanual examination is not necessary for asymptomatic temperature elevation. However, with a combination of fever, increasing tenderness, and new-onset pain, gentle bimanual examination is required to accurately identify the infection site and to exclude or diagnose a mass. Speculum examination usually is not required, and findings are similar with or without an existing infection. As is true for routine pelvic examination, most information at bimanual examination is obtained from the vaginal fingers. If a patient is too tender to allow adequate examination, vaginal sonography is indicated. Bowel function is usually not altered by soft-tissue cellulitis but can be by pelvic abscess or infected pelvic hematoma.
Pelvic infections following hysterectomy are polymicrobial, and for that reason, it is difficult to identify true pathogens. Research has demonstrated that bacteria recovered transvaginally from the pelves of infected and clinically uninfected women are similar. Accordingly, routine transvaginal culturing of women with cuff or pelvic cellulitis does not add useful information. Moreover, a surgeon should not wait for culture results before starting empiric broad-spectrum antibiotic therapy. However, if initial therapy is partially effective or unsuccessful, then a culture will more predictably identify pathogen(s) since therapy will have eradicated other species. The antibiotic regimen should be changed, and culture results may direct this change. In contrast, abscess or infected hematoma fluid are cultured since those species are less likely to be vaginal contaminants. The same is true for any fluid or purulent material present in an abdominal incision.
For many postoperative SSIs, imaging is not mandatory. However, if additional anatomic information is needed, then transvaginal sonography or CT scanning are the most often used, and selection depends on clinical circumstances and suspected etiology.
Essentially all women develop this infection at the vaginal surgical margin after hysterectomy (Fig. 3-14). Normal response to healing is characterized by small-vessel engorgement, which results in erythema and heat. There is vascular stasis with endothelial leakage resulting in interstitial edema, which causes induration. This area is tender, microscopic evaluation of a wet prep reveals numerous WBCs, and purulent discharge is seen in the vagina. This process usually subsides, does not require treatment, and accordingly, does not require reporting as a SSI.
Organ/space infections. A. Vaginal cuff cellulitis. The vaginal surgical margin is edematous, hyperemic, and tender, and there are purulent secretions in the vagina. Parametria and adnexa are normal during gentle bimanual examination. B. Pelvic cellulitis in the right parametrium. It is indurated and tender to palpation; no mass is present. C. Adnexal infection after hysterectomy. The parametria are normal. Tenderness without a mass is appreciated in the adnexal area.
The few women who do require treatment are usually those who present after hospital discharge with mild, but increasing, new-onset lower abdominal pain and have a yellow vaginal discharge. Findings are as above, but the vaginal cuff is more tender than anticipated at this interval from the initial surgical procedure. Oral antimicrobial therapy with a single broad-spectrum agent is appropriate (Table 3-20). A patient is then reevaluated in several days to assess therapeutic efficacy. This may be completed by phone or with an examination if necessary.
TABLE 3-20Empiric Antimicrobial Regiments for Postgynecologic Surgery Infections ||Download (.pdf) TABLE 3-20 Empiric Antimicrobial Regiments for Postgynecologic Surgery Infections
This is a common infection following either vaginal or abdominal hysterectomy. It develops when host humoral and cellular defense mechanisms, combined with preoperative antibiotic prophylaxis, cannot overcome the bacterial inoculum and inflammatory process at the vaginal surgical margin. The inflammatory process spreads into the parametrial region(s) resulting in lower abdominal pain, regional tenderness, and fever, usually during the late second or third postoperative day. There are no peritoneal signs and bowel and urinary function are normal, but the patient may note anorexia.
Patients are discharged on perhaps their first or second postoperative day following vaginal hysterectomy, and affected women may be at home before symptom onset. Hospitalization and treatment with an IV broad-spectrum antibiotic regimen found in Table 3-20 is indicated until a patient has been afebrile for 24 to 48 hours. She then may be redischarged home. Most patients requiring hospitalization for IV antibiotic therapy are discharged with a 5- to 7-day oral antimicrobial prescription. Single-agent therapeutic regimens have been shown in prospective randomized trials to be as effective as combination-agent regimens. These infections are polymicrobial, and the regimen selected must have coverage for gram-positive and gram-negative aerobic and anaerobic bacteria.
This infection is uncommon and presents almost exactly like pelvic cellulitis. The difference is in the location of tenderness during bimanual pelvic examination. The cuff and parametrial areas are not usually tender, but the adnexa are. This infection also may develop after tubal ligation, surgical therapy for ectopic pregnancy, or other adnexal surgery. Empiric antibiotic regimens are identical to those for pelvic cellulitis (see Table 3-20).
A rare but life-threatening complication following primarily vaginal hysterectomy is ovarian abscess. Presumably with this infection, surgery is performed in the late proliferative phase of an ovulatory menstrual cycle, and ovaries are in close proximity to the vaginal surgical margin. As expected, physiologic cuff cellulitis develops normally, but when ovulation occurs, local bacteria gain access to the ovulation site and the corpus luteum. The corpus luteum often is hemorrhagic, and the blood in this functional cyst provides a perfect medium for bacterial growth.
Affected women have an essentially normal postoperative course until approximately 10 days following surgery. At this time, they experience acute unilateral lower abdominal pain, which then involves multiple quadrants. These symptoms reflect rupture of their abscess and development of generalized abdominal peritonitis. Sepsis commonly follows, and this is a true gynecologic emergency. Immediate exploratory laparotomy is necessary, with IV administration of perioperative broad-spectrum antimicrobials, abscess evacuation, and adnexectomy if easily accessible. At a minimum, necrotic tissues are debrided. After hospital discharge, oral antibiotics are typically continued for an additional 5 to 7 days, and this is variable depending on the clinical course.
Similarly, women rarely may develop a tuboovarian abscess (usually a pyosalpinx) identical to that seen as an end result of acute PID. This process can be managed medically with IV antimicrobials, and surgery is usually not required unless rupture follows. Combination antimicrobial therapy is continued until a woman has been afebrile for 48 to 72 hours. At this point, IV antibiotics may be replaced by oral agents, which are continued outpatient to complete a 2-week course of therapy. Patients diagnosed with TOA are reevaluated approximately 3 days following hospital discharge and then again 1 and 2 weeks later to document abscess resolution.
Pelvic Abscess/Infected Pelvic Hematoma
Pelvic abscess not involving an adnexal structure may also uncommonly complicate hysterectomy (Fig. 3-15). This develops from blood, serum, and/or lymph collections following hysterectomy that provide an excellent milieu for the overgrowth of bacteria inoculated into the adjacent tissues during the surgical procedure. An alternative infection can originate within a surgical pelvic hematoma. With hematoma, a postoperative-day-1 hemoglobin classically is significantly lower than that predicted by measured intraoperative blood loss. Reoperation is not required in most instances, and fluid or blood product resuscitation suffices. Unlike women who develop tissue cellulitis following surgery and whose early symptom of infection is pain and not fever, women with an infected hematoma will have low-grade temperature elevation (>37.8°C) as their early finding. Pain is a late symptom for these women. Accordingly, women with an unexplained postoperative hemoglobin decrease are discharged with instructions to monitor their temperature twice daily for approximately 1 week. Temperatures ≥37.8°C typically warrant evaluation.
Pelvic abscess or infected hematoma that is extraperitoneal and cephalad to the vaginal margins.
Signs and symptoms of pelvic abscess or infected hematoma are midline, and a mass is discernible centrally. Transvaginal sonography can accurately characterize the dimensions (Fig. 3-16). For both, hospital readmission for therapy is usually necessary. Combination-agent IV antimicrobial therapy is indicated, and selected regimens provide gram-positive and gram-negative aerobic and anaerobic coverage. Additionally, opening the vaginal surgical margin, if possible, to allow drainage will aid treatment and accelerate patient response. This can usually be done in a treatment room early, avoiding return to the operating room. If necessary, these can be drained with sonographic transvaginal guidance or in the operating room. These abscesses or infected hematomas usually remain confined to the extraperitoneal space, and a patient does not usually develop peritonitis. Some patients may develop diarrhea due to the proximity of the rectum, which is usually adjacent to the infected space.
Transvaginal sonogram of an infected pelvic hematoma following hysterectomy. This 11 × 12 cm collection of blood and clot was drained vaginally in the operative room. (Used with permission from Dr. Elysia Moschos.)
Combination IV antibiotics are administered until a woman has been afebrile 48 to 72 hours. IV antibiotics may then be replaced by oral agents, which are continued outpatient to complete a 2-week course of therapy, if the abscess or hematoma is not drained. If drained, then oral agents continued for 5 to 7 days following IV agents typically is sufficient. Commonly, patients are reevaluated 3 days following hospital discharge and then again 1 and 2 weeks later to document infection resolution.
Abdominal Incision Infection
The superficial and easily accessible location of this infection aids its diagnosis. Although abdominal incision infection may develop alone or with pelvic infection following abdominal hysterectomy, it develops uncommonly after other gynecologic procedures. Unlike pelvic infection, the incidence of this infection is not altered by antimicrobial prophylaxis. Risk factors include obesity, immunosuppression, diabetes, excessive electrosurgical coagulation use, passive drains, and coexistent skin inflammation at the time of surgical incision.
Abdominal incisions are usually the most uncomfortable following gynecologic surgery, but pain decreases daily. Erythema and heat are the first physical signs of this infection, which is usually diagnosed on the fourth or fifth postoperative day—again, after discharge from the hospital. A hematoma or seroma may develop in the abdominal wall incision without infection. If these collections are large, opening of the incision and evacuation to prevent infection in those fluids is warranted. Similarly, pus requires incision opening to ensure an intact fascia, as should be done with large seromas or hematomas.
Drainage and local care are usually the basis of successful therapy for abdominal incision infection or for large hematoma or seroma. Wet-to-dry dressings stimulate fibroblastic proliferation and development of healthy granulation tissue. Moistening the dry dressing prior to its removal will ease removal and decrease patient discomfort. At this stage, secondary closure can be considered. Importantly, wounds are irrigated with normal saline. Povidone-iodine, iodophor gauze, hydrogen peroxide, and Daiken solution are avoided as they are caustic to healing tissues. Some recommend their use early but follow with normal saline irrigation. Negative-pressure wound therapy provided by vacuum-assisted wound closure devices is available for more serious or larger wound areas that are slow to respond once the wound has a clean, granulating base (Chap. 42).
If there is soft-tissue cellulitis adjacent to the incision, antimicrobial therapy is required. If the initial surgery was a clean procedure, then Staphylococcus species predominate. Following clean-contaminated or dirty procedures, isolated organisms commonly include gram-negative bacteria such as E coli, Pseudomonas aeruginosa, and Enterobacter species and gram-positive bacteria, namely, Staphylococcus and Enterococcus species (Kirby, 2009). Anaerobes are typically not prominent pathogens in these infections but may be present, especially following hysterectomy. Thus, these infections are usually polymicrobial. Antibiotics found in Table 3-20 are suitable regimens.
This condition, caused by an exotoxin (TSS toxin-1) produced by Staphylococcus aureus, appears approximately 2 days following surgery or menstruation onset. Menstrual-associated toxic shock syndrome (TSS) rates have diminished following changes in tampon composition and use. For TSS, the vagina or wound must be colonized by a toxigenic staphylococcal strain, and the patient must lack the specific antibody that can block the superantigen.
The classic TSS symptoms include fever, malaise, and diarrhea. If postoperative, there are minimal signs of wound infection. A patient has conjunctival and pharyngeal hyperemia without purulence. The tongue is usually reddened, and the skin on the trunk is erythematous but not painful or pruritic. Temperatures are usually above 38.8°C, and orthostatic hypotension or shock may be present. This syndrome results from host cytokines released in response to superantigenic properties of the toxin. The criteria for this diagnosis are presented in Table 3-21.
TABLE 3-21Criteria for Diagnosis of Toxic Shock Syndrome ||Download (.pdf) TABLE 3-21 Criteria for Diagnosis of Toxic Shock Syndrome
| Major criteria |
Systolic BP <90 mm Hg for adults
Diffuse macular erythroderma
Late skin desquamation, particularly on hands, palms, and soles (1–2 weeks later)
| Minor criteria (organ system involvement) |
Gastrointestinal: diarrhea or vomiting
Mucous membranes: oral, pharyngeal, conjunctival, and/or vaginal erythema
Muscular: myalgia or creatinine level greater than twice normal
Renal: BUN and creatinine greater than twice normal or >5 WBCs/hpf in urine, without concurrent UTI
Hematologic: platelet count <100,000 per mm3
Hepatic: SGOT, SGPT, and/or bilirubin levels greater than twice normal
Central nervous system: altered consciousness without focal localizing signs
The wound, if present, is treated like any other wound. It is cultured to confirm presence of S aureus. However, results from other cultures (e.g., blood, throat, and cerebrospinal fluid) will be negative. To meet the strict criteria, a woman must have all major and at least three minor criteria. If this is suspected early and therapy is initiated, the complete syndrome may not develop. Serologies for Rocky Mountain spotted fever, measles, and leptospirosis must be negative. Viral infection and group A streptococci can cause a similar presentation.
While awaiting culture results for selection of specific antistaphylococcal antibiotics, empiric therapy covers both methicillin-susceptible and methicillin-resistant S aureus. Vancomycin (15 to 20 mg/kg/dose) can be given every 8 to 12 hours, not exceeding 2 g per dose. Some experts argue for the addition of clindamycin, but further evidence is needed. Regardless, the hallmark of therapy is entire system support with large volumes of IV fluids and electrolytes to replace massive body fluid losses from diarrhea, capillary leakage, and insensible loss. These patients may develop significant edema and are best managed in an intensive care unit. Even with appropriate management, the death rate has been reported to be as high as 5 percent because of subsequent acute respiratory distress syndrome (ARDS), disseminated intravascular coagulopathy (DIC), or hypotension unresponsive to therapy with resultant myocardial failure. This syndrome may also follow gynecologic surgical procedures such as D & C, hysterectomy, urethral suspension, and tubal ligation.
Although described in the 1870s, it was not named until 1952, by a Parkland Hospital surgeon (Wilson, 1952). Risk factors for this postoperative incision infection are age older than 50 years, arteriosclerotic heart disease, diabetes mellitus, obesity, debilitating disease, smoking, and previous radiation therapy, all of which are associated with decreased tissue perfusion. In our clinical service, vulvar infection in obese diabetic women is a prominent risk. Only approximately 20 percent of cases follow surgery, the majority developing after minor injuries or insect bites. Bacteria recovered from women with this infection are similar to those recovered from any postoperative gynecologic infection site, namely predominantly E coli, E faecalis, Bacteroides spp, Peptostreptococcus spp, S aureus, and groups A and B hemolytic streptococci.
Although this postoperative superficial incisional infection begins like any other postoperative infection with pain and erythema, its hallmark is subcutaneous and superficial fascial necrosis, manifested by excessive tissue edema in adjacent areas. There also may be associated myonecrosis. Blisters or bullae form in tissue that has become avascular and is discolored (Fig. 3-17). Crepitus or induration and edema beyond the region of visible erythema may be present. Tissue destruction is far more extensive than is evident by surface examination. The skin will slip over underlying tissue, and if incised, due to the lack of vascularity, there will be no bleeding but instead usually a thin gray transudate. Severe systemic toxicity and fever may develop. In obvious cases, no imaging is needed, and patients are prepared for surgical debridement. In less-clear cases, radiographs or CT scans, if these can be quickly obtained, may add information by revealing gas in affected tissues produced by clostridial species such as Clostridium perfringens.
Vulvar necrotizing fasciitis in an obese, diabetic patient. A. Preoperative image of the perineum with notable edema and skin bullae. B. The required intraoperative resection was extensive (Used with permission from Dr. Laura Kilmer.)
Although broad-spectrum antibiotic administration is required, the cornerstone of treatment is prompt recognition and immediate surgical removal of necrotic tissue to a level at which viable bleeding tissue is reached. To achieve this, excision of large tissue volumes are often needed. Although this is potentially disfiguring, postponing surgery while waiting for antimicrobial activity only increases the volume of tissue death. Gynecologists may enlist assistance from a general surgeon or gynecologic oncologist if extensive debridement into the posterior perineal triangle, buttock, or inner thigh is anticipated. Early fatality rates for patients with this infection approximated 20 percent in the systematic review of 1463 patients by Goh and associates (2014).
Wounds are left open and treated as wound infections as described earlier with local hydrotherapy or a wound vacuum device. Assistance from a general surgeon for potential grafting is often necessary.
Methicillin-resistant Staphylococcus aureus
Any of the polymicrobial infections discussed in this section may be complicated by MRSA. To cover MRSA, suitable outpatient oral antibiotics for uncomplicated infection include trimethoprim-sulfamethoxazole DS (160 mg/800 mg) twice daily, clindamycin 300 or 450 mg three times daily, doxycycline or minocycline 100 mg twice daily, or linezolid (Zyvox) 600 mg twice daily. For complicated infections, the Infectious Disease Society of America recommends MRSA coverage with IV vancomycin, IV or oral clindamycin, IV or oral linezolid 600 mg twice daily, IV daptomycin (Cubicin) 4 mg/kg once daily, or IV telavancin (Vibativ) 10 mg/kg once daily (Liu, 2011). Newer FDA-approved agents against complicated MRSA infections include ceftaroline (Teflaro), dalbavancin (Dalvance), oritavancin (Orbactive), and tedizolid (Sivextro) (Holmes, 2014). These newer drugs are expensive and may have restricted formulary use to only infectious disease specialists.