Selected Podcast
Group B Streptococcal Infection in Pregnancy
Patrick Duff M.D. highlights group B streptococcal infection in pregnancy. He describes the principal risk factors for early-onset group B streptococcal infection, the most useful methods for identifying maternal group B streptococcal colonization and the best strategies for reducing the frequency of early-onset neonatal group B streptococcal infection. Lastly, he shares the special considerations for antibiotic prophylaxis in patients who are allergic to penicillin.
Featuring:
He has worked at the University of Florida for 24 years and has formerly served as the Residency Program Director and Director of Fellowship Research until stepping down in July 2013. He continues to serve as Associate Dean for Student Affairs.
Patrick Duff, M.D.
Dr. Duff attended college at Harvard University and then pursued a Master’s Degree in Public Administration at the University of Virginia. He then changed career plans and entered medical school at Georgetown University, where he graduated from and then began a long service obligation with the U.S. Army. While in military service, he completed residency training in Obstetrics and Gynecology at Walter Reed Army Medical Center and fellowship training in Maternal Fetal Medicine at the University of Texas in San Antonio. He has served as a faculty member at three of the Army’s major teaching centers: Walter Reed, Letterman, and Madigan. He completed his military service as Director of Obstetrics at Madigan Army Medical Center in Tacoma, Washington and retired from active duty, accepting a faculty position in the Division of Maternal Fetal Medicine at the University of Florida.He has worked at the University of Florida for 24 years and has formerly served as the Residency Program Director and Director of Fellowship Research until stepping down in July 2013. He continues to serve as Associate Dean for Student Affairs.
Transcription:
preroll: The University of Florida College of Medicine is accredited by the Accreditation Council for continuing medical education, ACCME to provide continuing medical education for physicians. The University of Florida College of Medicine designates this enduring material for a maximum of 0.25 AMA PRA category one credit. Physicians should claim only the credit commensurate with the extent of their participation in this activity.
Melanie Cole (Host): Welcome to UF Health Med Ed Cast with UF Health Shands Hospital. I'm Melanie Cole joining me is Dr. Patrick Duff. He's a Professor of Maternal Fetal Medicine at the University of Florida College of Medicine, and he practices at UF Health Shands Hospital.
He's here to highlight Group B Strep infection in pregnancy. Dr. Duff, it's a pleasure to have you join us today. Can you start by distinguishing between early and late onset Group B Strep infection?
Patrick Duff, M.D. (Guest): Yes. Thank you for having me. Early onset neonatal Group B Streptococcal infection typically occurs within the first seven days following delivery. It's usually manifested as either pneumonia, septicemia or meningitis and early onset neonatal Group B Streptococcal infection, almost always results from direct transfer of the organism from the colonized mother to the baby.
In contrast, late onset neonatal Group B Streptococcal infection typically occurs beyond the seventh day of life. And it tends to be manifested more as meningitis and septicemia. The prognosis for early onset neonatal Group B Streptococcal infection is usually a little worse than for late onset infection because more preterm babies tend to have the early onset version of the infection.
Host: Do we have some risk factors Doctor, do we know for early onset Group B Streptococcal infection? Do we have some group or risk that is higher than another?
Dr. Duff: Absolutely. There's been a tremendous amount of research in this field in the past 30 years. And there are several very well-defined risk factors for early onset neonatal Group B Streptococcal infection. One is prematurity. Second is prolonged labor, particularly in the presence of ruptured membranes. Indigent patients and women of color are probably at greater risk for having early onset neonatal Group B Streptococcal infection. Maternal fever during labor is also an important risk factor.
Host: So what are some of the most useful methods for identifying maternal Group B Strep colonization in the mother?
Dr. Duff: So that's very pertinent and wonderful question. I think today, the gold standard for identifying mothers who are colonized with Group B Streptococcal infection is a culture. The sample for the culture is typically taken from the lower portion of the vagina, the perenium and the area right around and just inside the anus and with optimal culture technique about 20 to 25% of all pregnant women will in fact be positive for Group B Streptococcal infection. The culture is typically done in a selective broth. When laboratories try to save money by not using selective culture media, they may miss up to 50% of colonized women.
Host: So then let's talk about strategies for reducing the frequency of early onset neonatal Group B Strep infection. And as we're talking about mitigation strategies and prevention, Dr. Duff, can you tell us a little bit about the ACOG policy statement that's been endorsed by the American Academy of Pediatrics, the American College of Nurse Midwives, the Association of Women's Health, Obstetric, and Neonatal Nurses, the Society for Maternal Fetal Medicine? It seems like all the big ones are endorsing these policy statements. So speak about those mitigation strategies and those policies initiatives?
Dr. Duff: Well, you're absolutely right. Through the years, there have been various organizations that have weighed in and suggested different methods preventing or reducing the frequency of neonatal Group B Streptococcal infection. And finally, in the last few years, we've had very good consensus among all the organizations that you cited, plus the Centers for Disease Control.
And I think the very best mitigation strategy that we have today is to do the following: in patient who presents to the labor and delivery suite in preterm labor with or without ruptured membranes, those individuals should be cultured for Group B Streptococcal infection and treated if colonized.
For all other patients, which of course is the majority of patients, the strategy today, and the standard of care is to perform atgenital track culture at 36 to 37 weeks gestation. If the patient tests negative, then she does not need prophylactic antibiotics during labor. If she tests positive, however, she should be targeted for antibiotic prophylaxis during labor. The two drugs of choice today for prophylaxis are penicillin or ampicillin. In patients that are allergic to penicillin, there are three alternate drugs that can be used depending on the type of allergy that the patient has. For patients with mild allergy to penicillin, the drug of choice is typically cefazolin, a first-generation cephalosporin. For patients who have more severe allergies to penicillin, the drugs of choice are either clindamycin, if you can document that the organism is sensitive to that antibiotic or vancomycin. These antibiotics should be started right at the time the patient is admitted to the labor and delivery suite and continued through the point in time that the patient is delivered. And with implementation of this particular strategy, the medical community has been able to decrease the rate of early onset neonatal Group B Streptococcal infection dramatically.
Host: Such an interesting topic. And thank you for speaking to those points and getting to my question about the special considerations for antibiotic prophylaxis in patients that have allergies to penicillin. I'd like you to speak to other providers now, Dr. Duff, what are some of the key takeaways and components for primary care physicians, obstetrician gynecologists, obstetric nurses, advanced care nurse practitioners, all of those healthcare providers that are involved. Can you speak to prevention, screening, reducing the incidence, kind of wrap it all up for us on Group B Strep infection and early onset neonatal disease.
Dr. Duff: Absolutely. So again, we need to screen all patients who unexpectedly are admitted to the hospital with preterm labor, with or without ruptured membranes. Everyone else, which is the vast majority of patients, should be cultured at 36 to 37 weeks of gestation for Group B Streptococcal infection. And I should point out that there are some rapid tests that are based on polymerase chain reaction methodology for Group B Streptococcal infection, but they are probably not as sensitive as the culture methodology. So perform cultures routinely at 36 to 37 weeks. Women that test positive, their charts should be flagged so that they can be treated intrapartum with prophylactic antibiotics.
These drugs are given intravenously. Therapy is begun right at the start of labor and continued until the patient has delivered. And I think a very subtle, but very important point here is that if the patient has a severe allergy to penicillin, the choice of alternate agents is either clindamycin or vancomycin.
But about 10 to 15% of strains of Group B Streptococcal infection, are in fact resistant to clindamycin. So if the laboratory has not done sensitivity testing to demonstrate that the organism is sensitive, the patient should be treated with vancomycin. If the organism is sensitive to clindamycin, then clindamycin can be used.
But vancomycin is essentially 100% effective against all strains of Group B Streptococcal infection. And recently the CDC revised some of its recommendations for dosing of both penicillin, ampicillin, cefazolin and clindamycin and vancomycin, and those dosing regimens are referenced in the article that you cited originally.
Host: What an excellent informative podcast this was. You're a great educator, Dr. Duff. And if people have questions, if other providers have questions related to this podcast, can you please give your email for them to contact you?
Dr. Duff: Absolutely. I would be delighted to answer any question that may have been generated by this discussion. And my email is Duff, all lower case, DUFF, P for Patrick@ufl.edu. duffp@ufl.edu.
Host: That's duffp@ufl.edu and Dr. Duff, I thank you so much for joining us and sharing your expertise with other providers today. To refer your patient, or to listen to more podcasts from our experts, please visit UFhealth.org/medmatters. That concludes today's episode of UF Health Med Ed Cast with UF Health Shands Hospital.
For updates on the latest medical advancements, breakthroughs and research, don't forget to follow us on your social channels. I'm Melanie Cole.
preroll: The University of Florida College of Medicine is accredited by the Accreditation Council for continuing medical education, ACCME to provide continuing medical education for physicians. The University of Florida College of Medicine designates this enduring material for a maximum of 0.25 AMA PRA category one credit. Physicians should claim only the credit commensurate with the extent of their participation in this activity.
Melanie Cole (Host): Welcome to UF Health Med Ed Cast with UF Health Shands Hospital. I'm Melanie Cole joining me is Dr. Patrick Duff. He's a Professor of Maternal Fetal Medicine at the University of Florida College of Medicine, and he practices at UF Health Shands Hospital.
He's here to highlight Group B Strep infection in pregnancy. Dr. Duff, it's a pleasure to have you join us today. Can you start by distinguishing between early and late onset Group B Strep infection?
Patrick Duff, M.D. (Guest): Yes. Thank you for having me. Early onset neonatal Group B Streptococcal infection typically occurs within the first seven days following delivery. It's usually manifested as either pneumonia, septicemia or meningitis and early onset neonatal Group B Streptococcal infection, almost always results from direct transfer of the organism from the colonized mother to the baby.
In contrast, late onset neonatal Group B Streptococcal infection typically occurs beyond the seventh day of life. And it tends to be manifested more as meningitis and septicemia. The prognosis for early onset neonatal Group B Streptococcal infection is usually a little worse than for late onset infection because more preterm babies tend to have the early onset version of the infection.
Host: Do we have some risk factors Doctor, do we know for early onset Group B Streptococcal infection? Do we have some group or risk that is higher than another?
Dr. Duff: Absolutely. There's been a tremendous amount of research in this field in the past 30 years. And there are several very well-defined risk factors for early onset neonatal Group B Streptococcal infection. One is prematurity. Second is prolonged labor, particularly in the presence of ruptured membranes. Indigent patients and women of color are probably at greater risk for having early onset neonatal Group B Streptococcal infection. Maternal fever during labor is also an important risk factor.
Host: So what are some of the most useful methods for identifying maternal Group B Strep colonization in the mother?
Dr. Duff: So that's very pertinent and wonderful question. I think today, the gold standard for identifying mothers who are colonized with Group B Streptococcal infection is a culture. The sample for the culture is typically taken from the lower portion of the vagina, the perenium and the area right around and just inside the anus and with optimal culture technique about 20 to 25% of all pregnant women will in fact be positive for Group B Streptococcal infection. The culture is typically done in a selective broth. When laboratories try to save money by not using selective culture media, they may miss up to 50% of colonized women.
Host: So then let's talk about strategies for reducing the frequency of early onset neonatal Group B Strep infection. And as we're talking about mitigation strategies and prevention, Dr. Duff, can you tell us a little bit about the ACOG policy statement that's been endorsed by the American Academy of Pediatrics, the American College of Nurse Midwives, the Association of Women's Health, Obstetric, and Neonatal Nurses, the Society for Maternal Fetal Medicine? It seems like all the big ones are endorsing these policy statements. So speak about those mitigation strategies and those policies initiatives?
Dr. Duff: Well, you're absolutely right. Through the years, there have been various organizations that have weighed in and suggested different methods preventing or reducing the frequency of neonatal Group B Streptococcal infection. And finally, in the last few years, we've had very good consensus among all the organizations that you cited, plus the Centers for Disease Control.
And I think the very best mitigation strategy that we have today is to do the following: in patient who presents to the labor and delivery suite in preterm labor with or without ruptured membranes, those individuals should be cultured for Group B Streptococcal infection and treated if colonized.
For all other patients, which of course is the majority of patients, the strategy today, and the standard of care is to perform atgenital track culture at 36 to 37 weeks gestation. If the patient tests negative, then she does not need prophylactic antibiotics during labor. If she tests positive, however, she should be targeted for antibiotic prophylaxis during labor. The two drugs of choice today for prophylaxis are penicillin or ampicillin. In patients that are allergic to penicillin, there are three alternate drugs that can be used depending on the type of allergy that the patient has. For patients with mild allergy to penicillin, the drug of choice is typically cefazolin, a first-generation cephalosporin. For patients who have more severe allergies to penicillin, the drugs of choice are either clindamycin, if you can document that the organism is sensitive to that antibiotic or vancomycin. These antibiotics should be started right at the time the patient is admitted to the labor and delivery suite and continued through the point in time that the patient is delivered. And with implementation of this particular strategy, the medical community has been able to decrease the rate of early onset neonatal Group B Streptococcal infection dramatically.
Host: Such an interesting topic. And thank you for speaking to those points and getting to my question about the special considerations for antibiotic prophylaxis in patients that have allergies to penicillin. I'd like you to speak to other providers now, Dr. Duff, what are some of the key takeaways and components for primary care physicians, obstetrician gynecologists, obstetric nurses, advanced care nurse practitioners, all of those healthcare providers that are involved. Can you speak to prevention, screening, reducing the incidence, kind of wrap it all up for us on Group B Strep infection and early onset neonatal disease.
Dr. Duff: Absolutely. So again, we need to screen all patients who unexpectedly are admitted to the hospital with preterm labor, with or without ruptured membranes. Everyone else, which is the vast majority of patients, should be cultured at 36 to 37 weeks of gestation for Group B Streptococcal infection. And I should point out that there are some rapid tests that are based on polymerase chain reaction methodology for Group B Streptococcal infection, but they are probably not as sensitive as the culture methodology. So perform cultures routinely at 36 to 37 weeks. Women that test positive, their charts should be flagged so that they can be treated intrapartum with prophylactic antibiotics.
These drugs are given intravenously. Therapy is begun right at the start of labor and continued until the patient has delivered. And I think a very subtle, but very important point here is that if the patient has a severe allergy to penicillin, the choice of alternate agents is either clindamycin or vancomycin.
But about 10 to 15% of strains of Group B Streptococcal infection, are in fact resistant to clindamycin. So if the laboratory has not done sensitivity testing to demonstrate that the organism is sensitive, the patient should be treated with vancomycin. If the organism is sensitive to clindamycin, then clindamycin can be used.
But vancomycin is essentially 100% effective against all strains of Group B Streptococcal infection. And recently the CDC revised some of its recommendations for dosing of both penicillin, ampicillin, cefazolin and clindamycin and vancomycin, and those dosing regimens are referenced in the article that you cited originally.
Host: What an excellent informative podcast this was. You're a great educator, Dr. Duff. And if people have questions, if other providers have questions related to this podcast, can you please give your email for them to contact you?
Dr. Duff: Absolutely. I would be delighted to answer any question that may have been generated by this discussion. And my email is Duff, all lower case, DUFF, P for Patrick@ufl.edu. duffp@ufl.edu.
Host: That's duffp@ufl.edu and Dr. Duff, I thank you so much for joining us and sharing your expertise with other providers today. To refer your patient, or to listen to more podcasts from our experts, please visit UFhealth.org/medmatters. That concludes today's episode of UF Health Med Ed Cast with UF Health Shands Hospital.
For updates on the latest medical advancements, breakthroughs and research, don't forget to follow us on your social channels. I'm Melanie Cole.