Prevalence of bloodstream pathogens is higher in neonatal encephalopathy cases vs. controls using a novel panel of real-time PCR assays.
BACKGROUND
In neonatal encephalopathy (NE), infectious co-morbidity is difficult to diagnose accurately, but may increase the vulnerability of the developing brain to hypoxia-ischemia. We developed a novel panel of species-specific real-time PCR assays to identify bloodstream pathogens amongst newborns with and without NE in Uganda.


METHODS
Multiplex real-time PCR assays for important neonatal bloodstream pathogens (gram positive and gram negative bacteria, cytomegalovirus (CMV), herpes simplex virus(HSV) and P. falciparum) were performed on whole blood taken from 202 encephalopathic and 101 control infants. Automated blood culture (BACTEC) was performed for all cases and unwell controls.


RESULTS
Prevalence of pathogenic bacterial species amongst infants with NE was 3.6%, 6.9% and 8.9%, with culture, PCR and both tests in combination, respectively. More encephalopathic infants than controls had pathogenic bacterial species detected (8.9%vs2.0%, p = 0.028) using culture and PCR in combination. PCR detected bacteremia in 11 culture negative encephalopathic infants (3 Group B Streptococcus, 1 Group A Streptococcus, 1 Staphylococcus aureus and 6 Enterobacteriacae). Coagulase negative staphylococcus, frequently detected by PCR amongst case and control infants, was considered a contaminant. Prevalence of CMV, HSV and malaria amongst cases was low (1.5%, 0.5% and 0.5%, respectively).


CONCLUSIONS
This real-time PCR panel detected more bacteremia than culture alone and provides a novel tool for detection of neonatal bloodstream pathogens that may be applied across a range of clinical situations and settings. Significantly more encephalopathic infants than controls had pathogenic bacterial species detected suggesting that infection may be an important risk factor for NE in this setting.
Clinical Research Department, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom; Mulago University Hospital, Kampala, Uganda.
Cally J
CJ
Tann
MRC/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.
Peter
P
Nkurunziza
Mulago University Hospital, Kampala, Uganda.
Margaret
M
Nakakeeto
MRC/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.
James
J
Oweka
National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom.
Jennifer J
JJ
Kurinczuk
MRC/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.
Jackson
J
Were
Mulago University Hospital, Kampala, Uganda.
Natasha
N
Nyombi
Institute for Women's Health, University College London, Medical School Building, London, United Kingdom.
Peter
P
Hughes
Clinical Research Department, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
Barbara A
BA
Willey
Clinical Research Department, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom; MRC/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.
Alison M
AM
Elliott
Institute for Women's Health, University College London, Medical School Building, London, United Kingdom.
Nicola J
NJ
Robertson
Institute for Child Health, University College London, London, United Kingdom; Department of Microbiology, Virology and Infection Control, Great Ormond Street Hospital for Children, London, United Kingdom.
Nigel
N
Klein
Institute for Child Health, University College London, London, United Kingdom; Department of Microbiology, Virology and Infection Control, Great Ormond Street Hospital for Children, London, United Kingdom.
Kathryn A
KA
Harris
D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology; D001483:Base Sequence; D001927:Brain Diseases / Q000097:blood* / Q000453:epidemiology* / Q000382:microbiology*; D016022:Case-Control Studies; D015897:Comorbidity; D003587:Cytomegalovirus / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004755:Enterobacteriaceae / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D017422:Sequence Analysis, DNA; D018139:Simplexvirus / Q000235:genetics; D013045:Species Specificity; D014454:Uganda / Q000453:epidemiology
D017931:DNA Primers