NEW Product MAY 2006

STREPTO B ID

NEW chromogenic media available !

STREPTO B ID

NEW PRODUCT in the bMx offer

SECOND in the NEW PREVENTION range

dedicated to the

“Screening of Strepto B for pregnant women”

……COMPLETE RANGE COMPLETE RANGE promoted globallypromoted globally

ToToddd Hewitt Broth+Ad Hewitt Broth+ATBs TBs ++

STREPTO B IDSTREPTO B ID ++

Slidex STREPTO BSlidex STREPTO B

= =

Greater reliability Greater reliability Validated solutionValidated solution

38

Bouillon Todd Hewitt + Antibiotiques- Réf. 42 116

Photo 1/2- rev.0 – 2002/11/05

Bouillon Todd Hewitt + Antibiotiques- Réf. 42 116

Photo 1/2- rev.0 – 2002/11/05

PRESCRIBE CONFIDENCE…

Proof :

ECCMID poster

P 798

Objective: The aim of this prospective study was to compare a method using the new chromogenic agar Strepto B ID (bioMérieux SA, France), Granada agar (Biomedics) and Columbia blood agar with colistin-nalidixic acid (BA-CNA) (bioMérieux), to detect vaginal colonization by group B streptococci (GBS) in pregnant women.Method: Specimens for GBS screening received over a 3 month period from pregnant women (683 vaginal swabs and 41 urine), 13 newborn gastric fluids at two hospitals were included and tested during this study. These specimens were cultured in parallel onto the three media by direct inoculation and after enrichment in Todd-Hewitt + antibiotics broth. Each medium was observed after 24 and 48hrs of incubation.Results: Overall GBS was detected in 255 cases (35%) on at least one medium after enrichment. Before and after enrichment, the sensitivity was 45.8% and 93.3% for Strepto B ID, 39.6% and 82.9% for Granada, 45.4% and 92.5% for BA-CNA respectively at 24hrs. Prolonged incubation (48hrs) enabled to increase the sensitivity: before and after enrichment, the sensitivity was 55.8% and 99.2.% for Strepto B ID, 52.5% and 92.9% for Granada, 52.9% and 96.7% for BA-CNA. Regarding the specificity, the Granada medium method gave 99.8% versus 97.3% for the Strepto B ID after enrichment and 48 hrs of incubation.Conclusion: These findings show that the Strepto B ID medium, the first chromogenic medium to detect GBS, is more sensitive than the Granada medium. However, the Granada medium method is more specific after enrichment and 48 hrs of incubation.The enrichment phase increases significantly the GBS sensitivity of detection especially with Strepto B ID. This new medium is easy to use due to the incubation under aerobic conditions.

Prevention of perinatal Group B streptococcal infections:Evaluation of a new chromogenic medium Strepto B ID C. Roure, V. Fiaty, Y. Gilles, H. Salord, S. Tigaud,

Hôpital de la Croix-Rousse, Laboratoire de Microbiologie, Lyon, France

P798

ABSTRACT

OBJECTIVES

RESULTS

CONCLUSION

The systematic screening for Group B Streptococci carriage is recommended at the end of pregnancy, ideally between the 34th and the 38th week of amenorrhea, in order to prevent neonatal Group B streptococcal infections. Culture techniques from vaginal cavity swabbing are currently the best.

Strepto B ID appears to be a very effective medium for the screening of Group B Streptococci. As for every chromogenic medium, a trained eye is necessary to pinpoint characteristic colonies.

According to the results obtained during this study, Strepto B ID is more sensitive than Granada medium.

GBS remains a leading cause of serious neonatal infections despite great progress in perinatal GBS disease prevention. The CDC recommends the use of a screening method for GBS colonization in pregnant women to identify candidates for intra-partum prophylaxis. Strepto B ID is a new, ready-to-use, chromogenic medium, designed for rapid identification of GBS. The aim of the study was to evaluate the biological performance of Strepto B ID on clinical samples.

Strepto B ID medium performance was compared to Granada medium and to Columbia CNA + 5% sheep blood, with and without previous selective enrichment, using biological samples.

Group B streptococcus is detected in 35% of the samples, whatever the medium.

Sensitivity of detection at 48 hours without enrichment on Strepto B ID, Granada and Columbia CNA media are respectively 56.1%, 52.2% and 52.9%. This sensitivity reaches 98.8%, 92.2%, 96.7% after previous enrichment. Whatever the method and the incubation period, the sensitivity of Strepto B ID medium is significantly higher than for the other two media.

Negative predictive values (reading at 48 hours) are 80.8 % (Strepto B ID) and 79.8% (Granada) without enrichment, and 99.4 % (Strepto B ID) and 96% (Granada) with previous enrichment.

MATERIAL AND METHODS

A total of 737 samples (683 vaginal swabs, 41 urine collections and 13 gastric fluids) were cultured, both directly and after previous selective enrichment (Todd Hewitt broth + antibiotics, bioMérieux, France) onto:

• Strepto B ID agar (bioMérieux, France)

• Granada medium (BIOMEDICS, Spain)

• Columbia CNA + 5% sheep blood agar (bioMérieux, France)

Culture plates were incubated at 38°C in aerobic (Strepto B ID, Columbia CNA) or anaerobic conditions (Granada) and interpreted after a period of incubation of both 24 and 48 hours.

Suspected colonies (red or pink on Strepto B ID [Fig. 1], red or orange on Granada, beta-hemolytic on Columbia-CNA) were GBS confirmed using a Slidex agglutination test (bioMérieux, France).

Statistical tests: Mac Nemar or binomial.

Reading at 24 hrs

Figure 1: GBS vaginal specimens collectionGBS colonies are pale pink to red, round and pearly

Table 1: Sensitivity of detection for Strepto B ID and Granada media

Table 2: Positive predictive values of Strepto B ID and Granada media, with and without enrichment.

Incubationperiod

Truepositives

Falsenegative

s

PPV[CI at 95%]

24 hrs

48 hrs

116

143

1

12

99.1%[95.2% - 99.9%]

92.3%*[86.8% - 95.6%]

24 hrs

48 hrs

98

133

0

0

100%[96.1% - 100%]

100%[97.1% - 100%]

24 hrs

48 hrs

238

252

6

13

97.5%[94.7% - 98.9%]

95.1%[91.7% - 97.1%]

24 hrs

48 hrs

207

235

0

1

100%[98.1% - 100%]

99.6%[97.6% - 99.9%]

Strepto B ID

Granada

Strepto B ID

Granada

Wit

h e

nri

ch

me

nt

Wit

ho

ut

en

rich

men

t

* Example of interpretation: without previous enrichment of a Strepto B-positive sample, there are 92.3 possibilities out of 100 that the colonies showing a characteristic coloration (pale pink to red) on Strepto B ID medium, after a period of incubation of 48 hrs, are Group B Streptococcal strains .

Incubationperiod

Truepositives

Falsenegative

s

Sensitivity of detection

[CI at 95%]

24 hrs

48 hrs

116

143

139

112

45.5%[39.4% - 51.7%]

56.1%*[49.8% - 62.1%]

24 hrs

48 hrs

98

133

157

122

38.4%[32.6% - 44.7%]

52.2%[45.9% - 58.3%]

24 hrs

48 hrs

238

252

17

3

93.3%[89.4% - 95.8%]

98.8%[96.5% - 99.6%]

24 hrs

48 hrs

207

235

48

20

81.2%[75.8% - 85.6%]

92.2%[88.1% - 94.9%]

Strepto B ID

Granada

Strepto B ID

Granada

Wit

h e

nri

ch

me

nt

Wit

ho

ut

en

rich

men

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* Example of interpretation: without previous enrichment of a Strepto B-positive sample, there are 56.1 possibilities out of 100 to detect a strain from this micro-organism on Strepto B ID medium, after a 48-hr period of incubation .