WHAT THIS EVIDENCE MEANS FOR PRACTICE
Until additional trials of the CMV vaccine are reported, we must focus on helping patients prevent acquisition of infection during pregnancy. Preventive measures include:
- safe sex practices
- use of CMV-negative blood for transfusion to pregnant women and their fetuses
- strict hand-washing procedures for mothers when changing diapers and caring for young children.
Extended-spectrum antibiotics reduce the rate of postcesarean wound infection
Tita ATN, Owen J, Stamm AM, Grimes A, Hauth JC, Andrews WW. Impact of extended-spectrum antibiotic prophylaxis on incidence of postcesarean surgical wound infection. Am J Obstet Gynecol. 2008;199:303e.1–303e.3 [Classification of evidence – Level II].
This prospective study describes surveillance for postcesarean wound infection during three different periods at the University of Alabama:
- 1992–1996, during which patients undergoing cesarean delivery routinely received prophylaxis with a first- or second-generation cephalosporin. Overall incidence of wound infection: 3.1%
- 1997–1999, during which patients were randomized to standard prophylaxis with cefazolin or to cefazolin plus either intravenous (IV) doxycycline or oral azithromycin. Overall incidence of wound infection: 2.4%
- 2001–2006, during which patients routinely received IV cefazolin plus IV azithromycin. Overall incidence of wound infection: 1.3%.
In each time period, the prophylactic antibiotics were administered after the infant’s umbilical cord was clamped. The p value for test of trend was highly significant (p<.002). The same significant trend was noted when superficial and deep wound infections were examined separately.
This evidence is a “practice changer”
For almost 20 years, the standard of practice has been to routinely administer prophylactic antibiotics to all women having cesarean delivery. Essentially, every published study has demonstrated a highly significant reduction in the frequency of postcesarean endometritis when patients received prophylaxis. Multiple studies also confirmed that a more limited-spectrum cephalosporin was as effective as an extended-spectrum agent in reducing the frequency of endometritis.5
Many of these earlier reports were unable to demonstrate a consistently beneficial effect of prophylaxis on the incidence of postoperative wound infection. That is why the present study is of such interest and importance. Tita and colleagues previously demonstrated an improved effect of extended-spectrum prophylaxis on the incidence of postcesarean endometritis.6 Now they have confirmed that this method of prophylaxis is also effective in lowering the rate of surgical wound infection.
Wound infections are more troublesome than endometritis
Wound infections—either incisional abscess or cellulitis—are even more likely than post-cesarean endometritis to prolong a patient’s postoperative stay and create the potential for severe morbidity, such as fascial dehiscence and necrotizing fasciitis. With the increasing prevalence of obesity in the US population, wound infections are likely to become even more frequent.
These infections typically are caused by aerobic streptococci and staphylococci from the skin, combined with coliform organisms and anaerobes from the pelvic flora. Incisional abscesses require surgical drainage; cellulitis usually will respond to a change in antibiotic therapy that specifically targets streptococci and staphylococci, along with the coliforms and anaerobes.
WHAT THIS EVIDENCE MEANS FOR PRACTICE
I strongly recommend routine prophylaxis with IV cefazolin (1 g) plus azithromycin (500 mg) in all women having cesarean delivery. Moreover, in view of several recent investigations that evaluated the timing of antibiotic administration (immediately preoperative versus after the umbilical cord is clamped), I recommend that extended-spectrum prophylaxis be given before the start of surgery.7
Duggal N, Mercado C, Daniels K, Bujor A, Caughey AB, El-Sayed YY. Antibiotic prophylaxis for prevention of postpartum perineal wound complications: a randomized control trial. Obstet Gynecol. 2008;111:1268–1273 [Classification of evidence – Level I].
Take note of this prospective, randomized, placebo-controlled trial of prophylactic antibiotics in women who sustained a third-or fourth-degree perineal laceration during vaginal delivery: It is the first, and only, well-designed trial of antibiotic prophylaxis for prevention of complications after repair of a major perineal laceration. Among patients in the study, 8% who received antibiotics developed a wound complication, compared with 24% of patients who received placebo, a statistically and clinically significant difference.
Details of the study
Eighty-three women received placebo, and 64 received a single IV dose of either cefotetan (1 g) or cefoxitin (1 g) before their perineal laceration was repaired. Patients who were allergic to penicillin received clindamycin (900 mg). The primary endpoints of the study were gross disruption of the wound or purulent drainage from the wound site 2 weeks after delivery.
Forty patients (27%) did not return for their post-partum appointment. Of the remaining patients, four of 49 (8%) who received antibiotics developed a wound complication, compared with 14 of 58 (24%) of those who received placebo (p=.037).