Application of the appropriate molecular biology-based method significantly increases the sensitivity of group B streptococcus detection results

BACKGROUND

Streptococcus agalactiae (group B streptococcus: GBS) is a leading cause of early- and late-onset diseases in neonates. Reliable results of GBS carriage investigation among pregnant women may decrease the incidence of neonatal infection and mortality.

AIM

To compare the results of conventional culture investigation with those of the US Food and Drug Administration-approved nucleic acid amplification test (BD Max GBS (Becton Dickinson)), and to establish our own protocols of standard polymerase chain reaction (PCR).

METHODS

A total of 250 vaginal-rectal swabs from three different hospitals in Bydgoszcz, Poland, were used to evaluate GBS carriage. Standard laboratory technique (overnight culture in broth enrichment media) results were compared with those of BD Max GBS assay (Becton Dickinson) and two standard PCR protocols, established to detect the cfb and 16S rRNA S. agalactiae genes, from the overnight cultures of the samples in the liquid enrichment media.

FINDINGS

The overall GBS carriage was estimated as 16.4-23.2%, depending on the applied detection method. The highest percentage of positive results, from each lab-oratory was obtained with the application of BD Max GBS assay. The differences in the number of positive results obtained with this particular method were statistically significant. Overall, 27 discrepancies were noted for the results obtained with the application of the methods compared.

CONCLUSIONS

The methods applied for GBS detection differ in sensitivity. A culture technique, though very specific, appears to be less sensitive at detecting S. agalactiae compared with the commercially available BD Max GBS assay or in-house PCR protocols established for this purpose.

[Differences by geographical information system in prevalence of disease in a farm animal practise]

INTRODUCTION

In the present study, the incidence of diseases in cattle in the area of a veterinary practice was analyzed spatially. Furthermore, the relationship between the incidence of diseases and the distance to geographical elements was investigated. For this study, all cattle farms that were customers of the ambulatory clinic of the animal hospital in Zurich (Tierspital Zürich) were exactly localized on a map. From clinical and treatment data program (Oblon Data®) all services and drugs between January 1st 2013 and December 31st 2013 were evaluated and added as attributes to the according farm. Along with the data of the animals kept on the respective farm, the relationship between prevalences and geographical elements was analyzed. Using these data, it was possible to define fifteen diseases of which incidences were spatially analyzed using a geographic information system (GIS). The results indicate that also on the level of a veterinary practice there are spatial differences in the incidence of diseases to find. However, the majority of diseases occur mainly in regions where the density of animals is also very high. As in earlier findings, this suggests that the size, the management and the proximity of a farm to the next farm (density) have a strong impact. A connection could be found between the distance to the geographical elements street, water and forest and the incidences of gastrointestinal parasitosis, claw disorders, reproduction disorders and cryptosporidiosis.