Preventing Neonatal GBS Disease: Putting Guidelines to the Test
Preventing Neonatal GBS Disease: Putting Guidelines to the Test
During a recent concert at the Park City International Music Festival, held annually in the scenic mountains of Utah, Scott Ballantyne, a New York-based cellist, told the audience a gruesome story about none other than Johannes Brahms, the highly regarded creator of symphonies, concertos, and chamber works. It seems that the beloved composer had a darker side -- he was a cat murderer, who incorporated felines' dying cries into his music. As the story goes, the Czech composer Antonin Dvorak, in appreciation for Brahms' tutelage, gave his mentor a "Bohemian sparrow slaying bow." Brahms would take aim from his apartment window in Vienna, and according to Richard Wagner, "after spearing the poor brutes, he reeled them in to his room after the manner of a trout-fisher. Then he eagerly listened to the expiring groans of his victims and carefully jotted down in his notebook their ante mortem remarks."
Now, we know how odd composers can be. Mozart had his quirks, such as a love of scatological humor, and Beethoven was reportedly a world-class slob in his personal habits, leaving his messy trail in nearly a hundred apartments during his life.
But as macabre as this story about Brahms is, it turns out not to be true. Calum MacDonald recently cleared Brahms of all charges, finding that the rumor was probably spread by none other than Wagner, a musical rival who intensely hated Brahms' work. Unfortunately, even more than 100 years later, one can still read reports of Brahms' supposed sadism and cruelty, especially in books by and for cat lovers.
What this bizarre bit of historical trivia illustrates is how a story can take on a life of its own, even obvious fabrications such as this. Unfortunately, the practice of medicine is not immune to incorporating beliefs, half-truths, and suppositions, especially when long held or promulgated by experts. Which is why it is vital that we regularly re-examine what we accept as true, especially when issued as guidelines.
A recent report by Schrag and colleagues from The New England Journal of Medicine provides such a service by evaluating the alleged equivalence of the 2 strategies for determining whether a pregnant woman should receive chemoprophylaxis to prevent transmission of group B Streptococcus (GBS) with regard to reducing the incidence of early-onset disease in neonates. The 2 strategies are:
The importance of this disease, and the necessity of using the best strategy to detect and prevent it, is shown by recent figures: even with a 70% decrease in the incidence of early-onset GBS disease since the promulgation of guidelines for chemoprophylaxis, 1600 illnesses and 80 deaths still occur annually, making it one of the leading causes of infection-related death in newborns in the United States.
This study was very large, in order to address the limitations of previous studies, which were generally focused on single hospitals. This group evaluated a randomized, representative selection of 5144 births, taken from more than 600,000 live births from 8 regions of the United States during 1998 and 1999, as part of the CDC's Active Bacterial Core Surveillance program. This sample included all reported cases of early-onset invasive GBS disease in the survey.
From their analysis, the investigators found that culture screening is better than risk assessment for determining who should receive intrapartum antibiotics. The authors state, "Routine screening for Group B streptococcus during pregnancy prevents more cases of early-onset disease than the risk-based approach." In fact, it appears that culture screening prevents twice as many cases as assessing risk factors. For the 312 cases of early-onset GBS detected by active surveillance and included in this study, more than half (62%) of the women had no risk factors for carriage. And 416 women in the screened group were culture positive for GBS but did not have clinical risk factors for transmission, such as fever, delayed delivery after membrane rupture, or preterm delivery.
There were a few other interesting findings from this study. First, women who had risk factors for GBS carriage were more likely to receive intrapartum antibiotics if they underwent culture screening rather than risk assessment, even though all women in the latter category should have received prophylaxis. It is not clear why this difference was seen. And second, a comparable number of women who were screened received intrapartum antibiotics as those who underwent risk assessment. It had been thought that more women evaluated by the screening strategy would receive antibiotics and would thus have a higher number of cases of antibiotic-related complications.
Nevertheless, even though we appear to be winning the battle against GBS, we might not be winning the war on neonatal infectious diseases. In a companion article by Stoll and coworkers, it appears that, indeed, the incidence of GBS sepsis has diminished substantially in extremely premature infants, dropping from 5.9 to 1.7 cases per 1000 live births between the earlier period of 1991-1993 and the later period of 1998-2000. Surprisingly, though, the overall rate for early-onset sepsis in this group of very-low-birthweight infants remained about the same. This is primarily due to Escherichia coli, especially strains resistant to ampicillin, which appears to be taking the place of GBS in causing early-onset sepsis.
This result is, again, not surprising. A number of clinicians feared that the greater use of chemoprophylaxis for preventing GBS disease might change both the "spectrum of organisms" and the organisms' susceptibility to antibiotics, which is what was seen in this study.
The results of these studies are reminiscent of a quote variously attributed to Oscar Wilde, Winston Churchill, and others: "No good deed goes unpunished." In fact, the trade-off for successful GBS prophylaxis is the same as with any antibiotic use, an increase in resistant organisms. This is now being seen with the quinolones, which have been gaining increased use for pulmonary and other infections, and with the newer classes of antibiotics such as the oxazolidinones and streptogramins.
In an accompanying editorial in the same issue, David Eschenbach of the University of Washington Medical Center in Seattle, Washington, proposed that we rapidly develop and widely use a GBS vaccine, so that we can avoid most intrapartum use of antibiotics and the selection of more dangerous and resistant pathogens. In addition, such a vaccine can help prevent early-onset infections that become established before antibiotics are given, such as is thought to occur in women with premature delivery. We can only add our voice to this call for a GBS vaccine.
Will these findings change the way you screen pregnant women at your hospital or clinic? Should we move ahead with a GBS vaccine? Let me know at harry_goldhagen@webmd.net.
(If you have technical concerns, please contact our customer support staff at medscapecustomersupport@webmd.net.)
During a recent concert at the Park City International Music Festival, held annually in the scenic mountains of Utah, Scott Ballantyne, a New York-based cellist, told the audience a gruesome story about none other than Johannes Brahms, the highly regarded creator of symphonies, concertos, and chamber works. It seems that the beloved composer had a darker side -- he was a cat murderer, who incorporated felines' dying cries into his music. As the story goes, the Czech composer Antonin Dvorak, in appreciation for Brahms' tutelage, gave his mentor a "Bohemian sparrow slaying bow." Brahms would take aim from his apartment window in Vienna, and according to Richard Wagner, "after spearing the poor brutes, he reeled them in to his room after the manner of a trout-fisher. Then he eagerly listened to the expiring groans of his victims and carefully jotted down in his notebook their ante mortem remarks."
Now, we know how odd composers can be. Mozart had his quirks, such as a love of scatological humor, and Beethoven was reportedly a world-class slob in his personal habits, leaving his messy trail in nearly a hundred apartments during his life.
But as macabre as this story about Brahms is, it turns out not to be true. Calum MacDonald recently cleared Brahms of all charges, finding that the rumor was probably spread by none other than Wagner, a musical rival who intensely hated Brahms' work. Unfortunately, even more than 100 years later, one can still read reports of Brahms' supposed sadism and cruelty, especially in books by and for cat lovers.
What this bizarre bit of historical trivia illustrates is how a story can take on a life of its own, even obvious fabrications such as this. Unfortunately, the practice of medicine is not immune to incorporating beliefs, half-truths, and suppositions, especially when long held or promulgated by experts. Which is why it is vital that we regularly re-examine what we accept as true, especially when issued as guidelines.
A recent report by Schrag and colleagues from The New England Journal of Medicine provides such a service by evaluating the alleged equivalence of the 2 strategies for determining whether a pregnant woman should receive chemoprophylaxis to prevent transmission of group B Streptococcus (GBS) with regard to reducing the incidence of early-onset disease in neonates. The 2 strategies are:
Screening all women for carriage of GBS at 35-37 weeks and providing prophylaxis to carriers during delivery; or
Assessing clinical risk factors for GBS carriage (which include intrapartum fever, a prolonged period [> 18 hours] between membrane rupture and delivery, or preterm delivery), and providing intrapartum antibiotics to suspected carriers.
The importance of this disease, and the necessity of using the best strategy to detect and prevent it, is shown by recent figures: even with a 70% decrease in the incidence of early-onset GBS disease since the promulgation of guidelines for chemoprophylaxis, 1600 illnesses and 80 deaths still occur annually, making it one of the leading causes of infection-related death in newborns in the United States.
This study was very large, in order to address the limitations of previous studies, which were generally focused on single hospitals. This group evaluated a randomized, representative selection of 5144 births, taken from more than 600,000 live births from 8 regions of the United States during 1998 and 1999, as part of the CDC's Active Bacterial Core Surveillance program. This sample included all reported cases of early-onset invasive GBS disease in the survey.
From their analysis, the investigators found that culture screening is better than risk assessment for determining who should receive intrapartum antibiotics. The authors state, "Routine screening for Group B streptococcus during pregnancy prevents more cases of early-onset disease than the risk-based approach." In fact, it appears that culture screening prevents twice as many cases as assessing risk factors. For the 312 cases of early-onset GBS detected by active surveillance and included in this study, more than half (62%) of the women had no risk factors for carriage. And 416 women in the screened group were culture positive for GBS but did not have clinical risk factors for transmission, such as fever, delayed delivery after membrane rupture, or preterm delivery.
There were a few other interesting findings from this study. First, women who had risk factors for GBS carriage were more likely to receive intrapartum antibiotics if they underwent culture screening rather than risk assessment, even though all women in the latter category should have received prophylaxis. It is not clear why this difference was seen. And second, a comparable number of women who were screened received intrapartum antibiotics as those who underwent risk assessment. It had been thought that more women evaluated by the screening strategy would receive antibiotics and would thus have a higher number of cases of antibiotic-related complications.
Nevertheless, even though we appear to be winning the battle against GBS, we might not be winning the war on neonatal infectious diseases. In a companion article by Stoll and coworkers, it appears that, indeed, the incidence of GBS sepsis has diminished substantially in extremely premature infants, dropping from 5.9 to 1.7 cases per 1000 live births between the earlier period of 1991-1993 and the later period of 1998-2000. Surprisingly, though, the overall rate for early-onset sepsis in this group of very-low-birthweight infants remained about the same. This is primarily due to Escherichia coli, especially strains resistant to ampicillin, which appears to be taking the place of GBS in causing early-onset sepsis.
This result is, again, not surprising. A number of clinicians feared that the greater use of chemoprophylaxis for preventing GBS disease might change both the "spectrum of organisms" and the organisms' susceptibility to antibiotics, which is what was seen in this study.
The results of these studies are reminiscent of a quote variously attributed to Oscar Wilde, Winston Churchill, and others: "No good deed goes unpunished." In fact, the trade-off for successful GBS prophylaxis is the same as with any antibiotic use, an increase in resistant organisms. This is now being seen with the quinolones, which have been gaining increased use for pulmonary and other infections, and with the newer classes of antibiotics such as the oxazolidinones and streptogramins.
In an accompanying editorial in the same issue, David Eschenbach of the University of Washington Medical Center in Seattle, Washington, proposed that we rapidly develop and widely use a GBS vaccine, so that we can avoid most intrapartum use of antibiotics and the selection of more dangerous and resistant pathogens. In addition, such a vaccine can help prevent early-onset infections that become established before antibiotics are given, such as is thought to occur in women with premature delivery. We can only add our voice to this call for a GBS vaccine.
Will these findings change the way you screen pregnant women at your hospital or clinic? Should we move ahead with a GBS vaccine? Let me know at harry_goldhagen@webmd.net.
(If you have technical concerns, please contact our customer support staff at medscapecustomersupport@webmd.net.)
Source...