GBS may be the cause of significant morbidity and mortality among pregnant women. In addition to urinary tract infections (UTIs), women may have chorioamnionitis, postpartum wound infection, bacteremia, or puerperal sepsis. Any pregnant mother with symptoms of a UTI should have a urine culture done, and the culture should be labeled as that of a pregnant woman. Because GBS bacteriuria is considered evidence of heavy colonization in the pregnant woman, any quantity of GBS in the urine of a pregnant woman should be reported by the laboratory to the obstetrician (19). Women who are symptomatic should be treated with standard therapy for the UTI. Whether a woman is symptomatic or asymptomatic, intrapartum antibiotics are recommended during labor for women who have bacteriuria (19). If a wound infection is suspected, cultures of the wound and blood should be obtained, and blood cultures are indicated in women with signs of bacteremia or sepsis. The diagnosis of chorioamnionitis is usually made on the basis of clinical signs, including fever, uterine tenderness, and tachycardia in the mother and tachycardia in the fetus (20). For women with chorioamnionitis, UTI, and bacteremia, the risk of colonization and disease in their infants is significantly increased.
Guidelines for Screening and Intrapartum Antibiotics
Most infants with early-onset disease are born to mothers who are only colonized with GBS and are asymptomatic. Guidelines for screening and providing intrapartum prophylaxis to pregnant women at risk for GBS to prevent early-onset neonatal disease were published in 1996 and 1997 by the American Academy of Pediatrics, American College of Obstetrics and Gynecology, and the Centers for Disease Control and Prevention (CDC) (21-23). Population-based surveillance by the Active Bacterial Core Surveillance/Emerging Infections Program Network found that these prevention efforts were successful in preventing invasive GBS disease and death in many infants (24).
Despite this progress, GBS continues to be an important cause of morbidity and mortality in neonates. The initial prevention strategies have been revised by a working group convened by the CDC in an effort to further decrease GBS disease in neonates (19). A key change in the most recent guidelines, relative to earlier guidelines, is that it is now recommended that all pregnant women have vaginal and rectal GBS screening cultures at 35-37 weeks of gestation to determine the risk of GBS disease in their newborn (19). Previously, one approach had recommended that assessment of a pregnant woman's risk could be based on factors known to increase the risk of neonatal GBS disease, including preterm delivery, rupture of membranes longer than 18 hours, and intrapartum fever (21). However, a population-based multistate surveillance study found that screening women based on cultures was significantly more effective in identifying women with colonization and preventing GBS disease in their infants (25). Now, the risk-based approach is recommended only in specific situations, including women who did not receive prenatal care or for whom results of cultures are not available (19).
For any woman having cultures positive for GBS, unless a planned cesarean section for delivery is performed and there is no labor or rupture of membranes, intrapartum antibiotics are recommended (19). Other recommended indications for intrapartum antibiotics can be found in the revised recommendations published by the CDC (19). The guidelines also provided recommendations for antibiotics for women who are allergic to penicillin and specific recommendations for obtaining cultures to enhance their sensitivity for detecting colonization. Recommendations for obtaining cultures are discussed in the Diagnostic Assays section.
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The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.