Group B Strep2010 CDC GBS REVISION

of 2002 guidelines

What’s new 2010CDC COPY & PASTE

MMWR November 19, 2010 / 59(RR10);1-32

WHATS NEW FOR THE LAB

• There are expanded options for laboratory detection of GBS, including use of pigmented media and PCR assays.

• There is a revised colony count threshold for laboratories to report GBS in the urine of pregnant women. The lab is not required to report a colony count < 10,000 ; however our lab reports down to 1,000; which still meets criteria for IPA GBS prophylaxis @ delivery

• Specifically recommend for patients who are at high risk for anaphylaxis to PCN to have CLINDAMYCIN INDUCIBLE RESISTANCE TESTING. OUR LAB HAS BEEN DOING THIS FOR SOME TIME NOW. THEY HAVE BEEN QUESTIONED WHETHER A SPECIFIC CHANGE IN THE LAB REPORT IS NECESSARY.

GBS BACTERURIA LAB CRITERIAIdentification of group B Streptococcus (GBS)

Bacteriuria in pregnant women• Routine screening for asymptomatic

bacteriuria is recommended in pregnant women, and laboratories should screen urine culture specimens for the presence of GBS in concentrations of 10,000 colony-forming units (cfu)/ml or greater.

• Laboratories should identify GBS when present at ≥10,000 cfu/ml in pure culture or mixed with a second microorganism.

NO CHANGE IN OB MANAGEMENTFOR GBS BACTERIURIA

• With the new guidelines, should I consider a woman GBS positive if her urine culture reports that she has <10,000 cfu/mL?

• A: Yes. If a urine culture is reported as positive for GBS,

that woman should be considered GBS positive. While guidelines now require that labs only report relatively high (i.e., 10,000 colony forming units/mL) colony counts of GBS in urine cultures, CDC recommends that providers treat all GBS positive urine cultures equally, regardless of colony count, and consider any woman with a urine culture positive for GBS to be GBS-positive for that pregnancy.

GBS BACTERIURIATREATED EARLIER WITH NEGATIVE F/U CULTURE

• Q: I have a patient who had a urine culture that was positive for GBS early in pregnancy; she was treated, and repeat urine cultures were negative. Does she still require intrapartum antibiotic prophylaxis?

• A: Yes. Studies have shown that GBS bacteriuria is a sign of heavy GBS colonization, which may not be entirely eradicated with treatment. GBS bacteriuria is a risk factor for having an infant with early onset GBS disease. This patient should thus receive intrapartum antibiotic prophylaxis, and does not require screening for GBS at 35-37 weeks because regardless of that screening result she will require intrapartum antibiotic prophylaxis.

WHATS NEW FOR PEDIATRICS

• The neonatal management algorithm’s scope was expanded to apply to all newborns.

• Consultation with obstetric providers to determine whether chorioamnionitis is suspected is important for guiding neonatal management.

• Guidelines provide management recommendations that depend upon clinical appearance of the neonate and other risk factors such as: maternal chorioamnionitis, ADEQUACY OF INTRAPARTUM ANTIBIOTICS, gestational age (<37 0/7) and duration of membrane rupture ( 18 hrs).

• The definition of Adequate Intrapartum Antibiotic Prophylaxis is clarified as ≥4 hours of IV penicillin, ampicillin, or cefazolin before delivery. • All other agents or durations are considered inadequate for purposes of

neonatal management.

• Changes were made to the algorithm to reduce unnecessary evaluations in well appearing newborns at relatively low risk for early-onset GBS disease.

WHATS NEW FOR OB• Recommendations for IAP agents are presented in an algorithm format in an effort

to promote use of the most appropriate antibiotic for penicillin-allergic women who are at “ HIGH RISK FOR ANAPHYLAXIS”.

• The definition of “ HIGH RISK FOR ANAPHYLAXIS” regarding PCN allergy is clarified to identify women who are candidates for IPA GBS prophylaxis with IV Clindamycin or Vancomycin.

• ONLY USE VANCOMYCIN AS AN ALTERNATIVE TO CLINDAMYCIN. Erythromycin is no longer an acceptable alternative for intrapartum GBS prophylaxis for penicillin-allergic women.

• The definition of Adequate Intrapartum Antibiotic Prophylaxis is clarified as

≥4 hours of IV penicillin, ampicillin, or cefazolin

before delivery.

• All other agents or durations are considered inadequate for purposes of neonatal management. RESULTING IN A THE OBSTETRICIAN TO HAVE HIGHER THRESHOLD TO DX “HIGH RISK FOR ANAPHYLAXIS” WHICH HAS BEEN DEFINED BY THE CDC.

GBS IPA INDICATED

• Previous infant with invasive GBS disease

• GBS bacteriuria during any trimester of the current pregnancy regardless of colony count or proof of cure culture after treatment of GBS bacteriuria

• Positive GBS vaginal-rectal screening culture during current pregnancy and within 5 weeks of delivery

GBS IPA INDICATED Unknown GBS status at the onset of labor

(culture not done, incomplete, or unknown)

• -- Delivery at <37 weeks' gestation

• -- Amniotic membrane rupture ≥18 hours

• -- Intrapartum temperature ≥100.4

WHAT DOES THE CDC CONSIDERHIGH RISK FOR ANAPHYLACTIC ALLERGY

• Patient with a history of any of the following after receiving penicillin or a cephalosporin are at high risk for anaphylaxis

• Anaphylaxis • Angioedema• Respiratory distress • Urticaria

• THESE PATIENTS SHOULD RECEIVE IAP WITH CLINDAMYCIN ONLY IF “ACCEPTABLE” SUSCEPTIBILTY TESTING REVEALS SENSITIVITY TO CLINDAMYCIN. Residual Neonatal management dilemma due to Clinda = “Inadequate IPA GBS Prophylaxis”

• Erythromycin is no longer an acceptable alternative for intrapartum GBS prophylaxis for penicillin-allergic women.

• VANCOMYCIN IS RECOMMENDED IF ADEQUATE SUSCEPTIBILITY TESTING FOR CLINDAMYCIN IS NOT AVAILABLE. Residual Neonatal management dilemma due to Vanco = “Inadequate IPA GBS Prophylaxis”

ANAPHYLACTIC RISK

• Q: Why is it important to assess for risk for anaphylaxis in GBS positive women who are penicillin-allergic?

• A: Assessing this risk will help you choose the most effective drug for intrapartum prophylaxis in your penicillin allergic patients. Unless a woman is at high risk for anaphylaxis (i.e., had angioedema, a history of anaphylaxis, respiratory distress, or urticaria following penicillin administration), cefazolin can and should be used. Cefazolin has similar pharmacokinetics to penicillin and concentrates very well in amniotic tissues, so it is strongly preferred over clindamycin which has limited ability to concentrate in fetal tissues and amniotic fluid.

HOW IMPORTANT IS IT TO USE ANCEF vs CLINDA OR VANCO

• Q: If a GBS positive patient has a history of penicillin allergy but is not high risk for anaphylaxis (i.e., has no history of anaphylaxis, angioedema, respiratory distress or urticaria after receiving penicillin or a cephalosporin), what antibiotic should she receive?

• A: Cefazolin is the drug of choice in this circumstance (Figure 8). Unfortunately, many providers prefer to use clindamycin because they are concerned about anaphylaxis to cefazolin. These clinicians may not realize that cefazolin has similar pharmacokinetics to penicillin and concentrates very well in amniotic tissues, so it is strongly preferred over clindamycin which has limited ability to concentrate in fetal tissues and amniotic fluid. Additionally, only approximately 10% of patients with penicillin allergy have immediate hypersensitivity reactions to cephalosporins; only 4 reports of nonfatal cases of anaphylaxis associated with GBS chemoprophylaxis have been published since 1996 when GBS guidelines for chemoprophylaxis were first released. Thus, while it may seem safer to choose clindamycin, the use of clindamycin over cefazolin may actually elevate the risk that intrapartum prophylaxis fails.

WHAT IS APPROPRIATE SUSCEPITIBILITY TESTING

• Q: My penicillin-allergic patient is at high risk for anaphylaxis, and I requested resistance testing be done on her culture. Her GBS culture was reported as 'resistant to erythromycin, and D zone positive.' What does this mean?

• A: When bacteria are resistant to erythromycin they can have inducible resistance to clindamycin; ordinary susceptibility testing won’t detect this. A separate test must be done for CLINDAMYCIN INDUCIBLE RESISTANCE , in addition to susceptibility testing. D-zone testing is one way of testing for inducible resistance; a positive result means that inducible resistance is present. In this example, the result signifies that the bacteria is resistant to erythromycin and has inducible resistance to clindamycin. This means that clindamycin is not an appropriate choice for intrapartum antibiotic prophylaxis for this patient. This patient, because she is at high risk for anaphylaxis to penicillin, should receive vancomycin.

VANCOMYCIN

• Q: I have a GBS positive patient who is allergic to penicillin, and has a history of urticaria and angioedema after receiving penicillin. I requested susceptibility testing but do not have the results. What antibiotic should she receive?

• A: Given that susceptibility testing results are not available, this patient should receive vancomycin for intrapartum antibiotic prophylaxis (Figure 8). It is preferable, however, to have susceptibility testing results available if at all possible as vancomycin is thought to be less effective than clindamycin with respect to intrapartum antibiotic prophylaxis for GBS. Vancomycin is also an agent to use judiciously since it is a drug of last resort for many bacterial infections

PEDS DILEMMASGBS IPA PROPHYLAXIS IN UTERO DURATION OF < 4 HRS

& CLINDA / VANCO NOT CONSIDERED “ ADEQUATE “• The definition of adequate intrapartum antibiotic prophylaxis is clarified

as ≥4 hours of IV penicillin, ampicillin, or cefazolin before delivery. All other agents or durations are considered inadequate for purposes of neonatal management.

• Well-appearing infants whose mother had an indication for GBS prophylaxis but received no or inadequate intrapartum antibiotics can be managed with observation for ≥48 hours, UNLESS the infant is <37 weeks and 0 days' gestational age OR membranes were ruptured ≥18 hours before delivery, in which case a limited evaluation AND observation for ≥48 hours is recommended

• Based on Escobar et al; & Additional data; 24 hr neonatal observation may be an option for IPA with “adequate IPA prophylaxis” In a well appearing infant IF >36 6/7 and rom < 18 hrs. Close follow up as an outpatient for a 24 hr discharge as detailed by the CDC for those who meet all criteria for “adequate IPA prophylaxis” is already part of the KP process.

• Unanswered question is what will Peds observation period and work up consist of for Clinda or Vanco IPA prophylaxis AND duration of IPA < 4 hours. NICU regional 01/20.

Pediatrics 2000;106:256 Obstet Gynecol 2006;108:1254 Pediatrics 2000;106:244 Obstet Gynecol 2008;112:265Pediatr Infect Dis J 2003;22:430 Obstet Gynecol 1998;91:112

KP DATAEscobar & Bromberger

• It has been demonstrated that 99 % of babies who develop early onset GBS sepsis develop sx/sx within the first 24 hrs

• Based on this information the CDC & SCAL KP allows some discretion regarding subsequent work up and neonatal observation for GBS sepsis.

• SCAL KP pediatrics may not consider it mandatory for the mother to have received antibiotics >/= to 4 hours prior to delivery. NICU REGIONAL 01/20 may address this issue

Pediatrics 2000;106:256. EscobarPediatrics 1999;103:703. Mohle-Boetani….., Escobar et alPediatrics. 2000;106:244. Bromberger

HOW TO CULTURE

• Q: To screen for GBS, do I have to do a vaginal swab, a rectal swab, or both?

• A: Current guidelines require a vaginal & rectal swab, because the sensitivity of vaginal-rectal swab is higher than vaginal swabs alone for detection of GBS. To obtain an adequate sample, a provider should swab inside of the lower vagina (introitus) and then insert the swab through the anal sphincter. The same swab can be used, or 2 different swabs can be used, if desired.

? WHEN TO CULTURE ?@ 35-37 WEEKS

• Q: If a culture is done at 35 weeks gestation and it is negative, and the patient comes in at 41 weeks gestation (more than 5 weeks later), does another culture need to be done?

• A: No. All women should be screened between 35-37 weeks; if this result is negative, then no further testing needs to be done. However, if a woman is cultured before 35 weeks, she should be rescreened if presenting for labor 5 or more weeks later.

GBS culture 5 VS 6 WEEKS

• The CDC considers a culture > 5 weeks from delivery invalid.

• Positive predictive value of a GBS culture decreases significantly to 43% if done 6 weeks or more prior to delivery.

• Studies have shown that testing within 5 weeks of delivery is most accurate at predicting GBS status at delivery, with a negative predictive value of 95-98% and a positive predictive value of 87-100% if performed in that time period.

Dr Montgomery prefers GBS CULTURE @ 36 wks to ensure all deliveries occur within 5 weeks of the culture because ~ 10 %

may not be delivered until 42 0/7

• The negative predictive value of GBS cultures performed ≤5 weeks before delivery is 95%–98%; however, the clinical utility decreases when a prenatal culture is performed more than 5 weeks before delivery because the negative predictive value declines. THEREFORE THE CDC CONSIDERS A CULTURE > 5 WEEKS INVALID

• GBS IPA PROPHYLAXIS PTL OR pPROM FOR 36 6/7 WEEKS OR LESS IF CULTURE IS UNKOWN DUE TO HIGH RISK OF GBS SEPSIS PRIOR TO 37 WEEKS

EFFICAY FOR < 37 0/7 WEEKS

• When penicillin, ampicillin, or cefazolin prophylaxis was administered for ≥4 hours before delivery to women delivering at <37 weeks’ gestation, antibiotic prophylaxis was 78% (95% confidence interval: 44%–91%) effective in preventing early-onset GBS disease (CDC, unpublished data, 2009).

PTL INTACT MEMBRANES < 37 0/7 WEEKS

• Perform GBS culture on admission if no culture is available within the preceding 5 weeks to guide management.

• IF IN LABOR AND NO GBS CULTURE RESULTS START GBS IAP.

• If a GBS culture is NEGATIVE within 5 weeks of presentation NO GBS IAP indicated.

• Patient should be regularly assessed for progression to true labor; if the patient is considered not to be in true labor, discontinue GBS prophylaxis.

• If GBS culture results become available prior to delivery and are negative, then discontinue GBS prophylaxis.

PpROM / PROMGBS IPA PROPHYLAXIS ONLY IF NO culture within 5wk

MAGNESIUM SULFATE NEUROPROPHYLAXIS UNTIL 34 0/7 FOR IMMINENT DELIVERY

•LATENCY ANTIBIOTICS INCLUDING AMPICILLIN FOR 7 DAYS IF </= 33 0/7 WEEKS OR UNTIL DELIVERY

•IF > 33 0/7 & < 34 0/7 WEEKS LATENCY ANTIBIOTICS UNTIL DELIVERY @ 34 0/7 ( presuming indxn @ 34 wks)

• GBS IPA IF NO CULTURE @ 34 0/7 THROUGH 37 0/7

GBS CULTURES FORR C/S PATIENTS

• Q: Do I still need to screen a woman for whom I am planning a cesarean delivery?

• A: Yes, Since it is not possible to predict if a woman will labor or rupture membranes prior to cesarean delivery, women for whom a cesarean section is planned should still be screened for GBS because GBS positive women will still need prophylaxis if cesarean delivery is performed after onset of labor or after rupture of membranes IPA GBS PROPHYLAXIS IS INDICATED.

• GBS IPA IS NOT INDICATED IF Cesarean delivery is performed before onset of labor with intact amniotic membranes, regardless of GBS colonization status or gestational age

AMNIOTOMY

• Should I delay amniotomy in a GBS+ woman until she has received adequate prophylaxis?

• A: Although concern has been raised that artificial membrane rupture could facilitate transmission of GBS from mother to infant, available data are not sufficient to demonstrate risk or to guide the timing of amniotomy or other procedures intended to facilitate progression of labor in GBS-colonized women. Intrapartum antibiotic prophylaxis is optimal if ≥4 hours in duration, and if possible, amniotomy should be timed accordingly. However, no medically urgent procedure should be delayed in order to achieve a certain duration of intrapartum antibiotic prophylaxis.

Chorioamnionitis

• Maternal Temperature of 100.4 ALONE IS CONSIDERED DIAGNOSTIC FOR CHORIOAMNIONITIS BY THE CDC

Chorioamnionitis by maternal temperature alone ie (not necessarily accompanied by 2 or more)

• Tachycardia (fetal 160/maternal 100)• WBC ≥ 15k• Foul odor• Uterine tenderness

• Chorioamnionitis is associated with an increased RR for Cerebral Palsy ( 2-4 fold)

Obstet Gynecol 2010;116:387–92 Meta AnalysisJAMA 2000; 284:1417 JAMA 2003: 290:2677

CHORIOAMNIONITISCDC & EPIDEMIOLOGICAL DATA

• CDC quote…In an effort to avert neonatal infections, maternal fever alone (100.4) in labor may be used as a sign of chorioamnionitis and hence indication for antibiotic treatment, particularly among women with a significant risk factor for chorioamnionitis (e.g., prolonged labor or prolonged rupture of membranes ( > 18 HOURS).

• A LOWER MATERNAL TEMPERATURE MAY BE ASSOCIATED WITH AN INCREASED RISK FOR GBS SEPSIS especially IF associated with other findings ( fetal or maternal tachycardia, uterine tenderness, foul/purulent amniotic fluid) J Infect Dis. 1983 Nov;148(5):795-801

• TEMPERATURE SHOULD BE TAKEN WITH TYMPANIC MEMBRANE THERMOMETER

Chorioamnionitis Dx with 100.4“UpToDate”

• Other criteria are insensitive and not specific and may delay the initiation of antibiotics . For clinical research, the diagnosis of Chorioamnionitis has been based upon the presence of maternal fever of greater than 38 degrees C (100.4 F) and at least two of the following conditions:– Maternal leukocytosis (greater than 15,000 ) – Maternal tachycardia (greater than 100 beats/minute) ( may be late

finding delayed until SIRS occurs)– Fetal tachycardia (greater than 160 beats/minute) Low sensitivity

HOWEVER specific for neonatal sepsis)– Uterine tenderness ( difficult to assess due to epidural )

- Foul odor of the amniotic fluid ( Low sensitivity ; however specific when present)

• Effect of epidural on maternal temperature is very unlikely to raise the temperature 1.5 degrees F or higher.

Original GBS Risk Factor Identification Cohort with > 30,000 patients

• FEVER (defined as > 99.5 or 37.5) in this cohort was identified as a significant risk factor for GBS sepsis

• Attack rates were increased to 6.5 per 1,000 infants born to mothers with intrapartum fever (relative risk, 4.0; P < 0.(01).

• “This attack rate is likely to be an underestimation, since only a small proportion of parturient women with fever did not receive antimicrobial therapy during labor and delivery”

J Infect Dis. 1983 Nov;148(5):795-801

If a patient is going to manifest an elevated temperature from an epidural the literature has demonstrated it typically occurs within the first 4 hours after epiduralResults closely resemble the findings of Camann who demonstrated a maternal temperature increase of 1.3ºF versus 1.1ºF (0.33ºF/hr in the first 4 hours).

Br J Anaesth 1991;67:565–8. Obstet Gynecol 2007;109:687–90

PEDIATRIC IMPLICATIONS OF DIAGNOSING CHORIOAMNIONITIS

• Well-appearing newborns whose mothers had suspected chorioamnionitis should undergo a limited evaluation and receive antibiotic therapy pending culture results. The evaluation should include a blood culture and a CBC including white blood cell differential and platelet count; no chest radiograph or lumbar puncture is needed.

• Consultation with obstetric providers to assess whether chorioamnionitis was suspected is important to determine neonatal management

REGIONAL GUIDANCE

• Requested that all maternal temperatures in labor be performed with tympanic membrane thermometer.

• Question Re : Peds / KP guidelines addressing “adequate” DURATION ( ie < 4 hours) and “adequate” ANTIBIOTICS ( Clinda & Vanco) due to the potential impact on both OB management and Neonatal management.

• The lab is and has been testing for inducible clindamycin resistance for some time. Is a change in the report necessary?

• Given the potential impact of not receiving “adequate IPA GBS prophylaxis” according to CDC guidelines, is PCN allergy testing warranted in patients with a questionable history? Sensitivity testing is a 3 phase process; skin testing, followed by intradermal injection, followed by a PO dose of Amoxicillin, followed by 1 hr of observation. All performed @ one visit and requires ~ 3-4 hours.

WHAT DOES THE CDC CONSIDERHIGH RISK FOR ANAPHYLACTIC ALLERGY

• Patient with a history of any of the following after receiving penicillin or a cephalosporin are at high risk for anaphylaxis

Anaphylaxis

Angioedema Respiratory distress

Urticaria

History for an Allergic Reaction• What were the symptoms and signs? ( swollen lips tongue/difficulty

breathing)

• The timing of onset of the reaction (immediately after an IV dose, or after several days from the initiation of a PO course of therapy)

• Did the patient require medical treatment or hospitalization because of the reaction?

• If treatment was given what was the response to that treatment (including the duration of reaction)

• How long ago/or reliable is the history of the reaction?

• Has the patient received that medication or a related medication again since the reaction? If so, were there recurrent symptoms?

• Any prior or subsequent history of exposure to other agents in that class, and presence or absence of any associated reactions

ANGIODEMA

• Angioedema typically affects areas with loose connective tissue, such as the face, lips, mouth, and throat, larynx, uvula, extremities, and genitalia.

• Bowel wall angioedema presents as colicky abdominal pain.

• Angioedema can be distinguished clinically from other forms of edema by the following characteristics:

Onset in minutes to hours

Asymmetric distribution

Tendency not to involve gravitationally dependent areas

Involvement of face, lips, larynx, and bowels

WHAT IS URTICARIA

• The term "hives" is used nonspecifically by patients, and the clinician is often faced with the task of discerning whether a patient truly had urticaria after the lesions have resolved.

• A typical urticarial lesion is an intensely pruritic, erythematous plaque

Confirmation that the lesions are urticaria

• A typical urticarial lesion is an intensely pruritic, erythematous plaque

• Individual lesions usually appear over the course of minutes, enlarge, may coalesce with other lesions, and then disappear within a few hours.

Sx / Sx associated withANAPHYLAXIS

• Urticarial Skin lesions OR Mucosal Swelling (lips, tongue , uvula) AND• Chest tightness or difficulty breathing• Hoarse voice or throat tightness OR • Low BP systolic < 90 or significant orthostatic sx