PCR for the detection of pathogens in neonatal early onset sepsis.

BACKGROUND: A large proportion of neonates are treated for presumed bacterial sepsis with broad spectrum antibiotics even though their blood cultures subsequently show no growth. This study aimed to investigate PCR-based methods to identify pathogens not detected by conventional culture. METHODS: Whole blood samples of 208 neonates with suspected early onset sepsis were tested using a panel of multiplexed bacterial PCRs targeting Streptococcus pneumoniae, Streptococcus agalactiae (GBS), Staphylococcus aureus, Streptococcus pyogenes (GAS), Enterobacteriaceae, Enterococcus faecalis, Enterococcus faecium, Ureaplasma parvum, Ureaplasma urealyticum, Mycoplasma hominis and Mycoplasma genitalium, a 16S rRNA gene broad-range PCR and a multiplexed PCR for Candida spp. RESULTS: Two-hundred and eight samples were processed. In five of those samples, organisms were detected by conventional culture; all of those were also identified by PCR. PCR detected bacteria in 91 (45%) of the 203 samples that did not show bacterial growth in culture. S. aureus, Enterobacteriaceae and S. pneumoniae were the most frequently detected pathogens. A higher bacterial load detected by PCR was correlated positively with the number of clinical signs at presentation. CONCLUSION: Real-time PCR has the potential to be a valuable additional tool for the diagnosis of neonatal sepsis.

Pathophysiological Mechanism of Extravasation via Umbilical Venous Catheters.

A rare complication of umbilical venous catheter (UVC) insertion is the extravasation of the infusate into the peritoneal cavity. We report 3 cases of abdominal extravasation of parenteral nutrition (PN) fluid via UVCs. Two of these cases presented as "acute abdomen" which were assumed to be necrotizing enterocolitis clinically; however, during postmortem, PN ascites and liver necrosis were found. A further case is described in an infant with congenital diaphragmatic hernia. While we were unable to ascertain direct vessel perforation by the catheter in any of these cases, based on pathological and histological examination, the proposed mechanism of PN fluid extravasation is leakage through microinjuries of liver vessel walls and necrotic parenchyma. PN extravasation should be considered as a differential diagnosis of acute abdomen when PN is infused via an UVC presumably as PN may have a direct irritant effect on the peritoneum.

Epidemiology of UK neonatal infections: the neonIN infection surveillance network.

OBJECTIVE: To describe the epidemiology of neonatal infection over the past decade in UK neonatal units. DESIGN: Retrospective analysis of prospectively collected infection surveillance network data from 2005 to 2014. SETTING: 30 neonatal units in the UK. PATIENTS: Newborns on participating neonatal units who had a positive blood, cerebrospinal fluid or urine culture and were treated with at least 5 days of appropriate antibiotics. RESULTS: 2171 episodes of neonatal infection in 1922 infants were recorded. The incidence of infection was 6.1/1000 live births and 48.8/1000 neonatal admissions (2.9 and 23.5 respectively if coagulase-negative staphylococci (CoNS) cultures excluded). The incidence of infection showed a statistically significant reduction over time with reductions in the rates of both early-onset sepsis (EOS) and late-onset sepsis (LOS).The majority of episodes (76%) represented LOS (diagnosed > 48 hours after birth), and infection was more common in premature (<37 weeks gestation) and low birth weight (<2500 g) neonates (84% and 81%, respectively). Commonly identified pathogens included group B streptococci (43%) and Escherichia coli (18%) for EOS, while E. coli (15%), Staphylococcus aureus (14%) and CoNS were prominent causes of LOS. CONCLUSIONS: This paper describes the epidemiology of neonatal infection in the UK over the past decade. These data enable benchmarking of practice and inform areas of future research and guideline development. The results support the hypothesis that the introduction of infection prevention care bundles and antibiotic stewardship programmes in the UK has reduced the burden of LOS.

Antimicrobial resistance in UK neonatal units: neonIN infection surveillance network.

OBJECTIVE: To define the susceptibilities of the common causative pathogens of neonatal sepsis in the UK. DESIGN: Retrospective analysis of the prospectively collected neonIN infection surveillance network data between 2005 and 2014. SETTING: 30 neonatal units in the UK. PATIENTS: Newborns admitted to participating neonatal units who return a positive blood, cerebrospinal fluid or urine culture and are treated with at least 5 days of appropriate antibiotics. RESULTS: 1568 isolates with recorded antimicrobial data were collected including 328 early-onset sepsis (EOS) isolates and 1240 late-onset sepsis (LOS) isolates. The majority of EOS pathogens (>92%) were susceptible to the four empirical commonly used antimicrobial combinations (eg, 93% for benzylpenicillin/gentamicin), while LOS pathogens demonstrated higher levels of resistance (eg, 89% for flucloxacillin/gentamicin). Among infants<1500 g and <32 weeks gestation, an amoxicillin/gentamicin combination demonstrated a trend towards improved coverage of EOS isolates than benzylpenicillin/gentamicin (93% vs 86%, p=0.211). CONCLUSIONS: This analysis provides insights into the patterns of antimicrobial resistance among UK neonatal pathogens. These data will inform areas of future research and can be used to update national evidence-based guidelines on antimicrobial usage.

AN AUDIT OF VANCOMYCIN PLASMA CONCENTRATIONS WHEN VANCOMYCIN IS ADMINISTERED BY CONTINUOUS INTRAVENOUS INFUSION IN NEONATES.

AIM: To compare continuous intravenous infusions of vancomycin in achieving desired therapeutic plasma concentrations against an intermittent bolus regimen. METHOD: Data were collected for all babies who received a continuous infusion of vancomycin on our Neonatal Intensive Care Unit (NICU) between October 2014 and March 2015. The regimen is based on that of another hospital (Hospital A) and comprised of a loading dose of 15 mg/kg over 1 hour followed by a continuous infusion of 20-50 mg/kg/day according to creatinine and corrected gestational age (CGA). The desired therapeutic range is 15-25 mg/L. The data recorded were date and time vancomycin was commenced, corrected gestational age (CGA), day of life and creatinine level at commencement, and the dose administered in mg/kg/day. Plasma concentrations were recorded as first, second or subsequent. Babies who switched from intermittent regimen were excluded. Results were analysed according to plasma concentration i.e. first, second or subsequent and stratified by CGA, day of life and creatinine level.All concentrations were obtained retrospectively for the period January to July 2014 when vancomycin was administered by intermittent bolus regimen to allow comparison of effectiveness.The doses of vancomycin were prepared at ward level by trained neonatal nurses as there is no aseptic facility onsite.We also compared our findings with those of another hospital from 2012. RESULTS: 49 babies received continuous vancomycin infusions and 115 plasma concentrations were analysed.Overall 62% of concentrations were within desired therapeutic range. This comprised 60.8% of first concentration, 60% of second concentration and 65.6% of subsequent concentrations. In relation to gestational age, 55.9% of concentrations for those 23-28+6 weeks CGA, 59.4% of concentrations for those 29-34+6 weeks CGA and 70.2% of concentrations for those >35 weeks CGA were in the therapeutic range.84.6% of concentrations for those 0-6 days old, 58% of concentrations for those 7-28 days old and 60% of concentrations for those >29 days old were in therapeutic range. 62% of concentrations for those with a Cr<50 micromol/L, 69% of concentrations for those with a Cr50-70 micromol/L and 50% of concentrations for those with a Cr>70 micromol/L were in the desired therapeutic range.Adjusting the data to allow for 10% variability in the target range achieved 71.3% of all concentrations in desired therapeutic range (13.5-27.5 mg/L).Compared to the plasma concentrations obtained on intermittent bolus regimen the percentage of concentrations in the desired therapeutic range has increased from 28% to 62%.Compared to the other hospital's data, the percentage of concentrations in the desired therapeutic range is lower at 62% compared to their 77%. CONCLUSION: Continuous infusions of vancomycin are more effective than intermittent bolus dosing in achieving desired therapeutic concentrations. Stratification of results has not shown any appreciable difference between the groups receiving vancomycin. However, extrapolation of our findings to those from other work, where prefilled syringes prepared in pharmacy are used is limited. It is known that there is significant variability from the desired target concentration of syringes prepared at ward level. There is a need to look at procuring prefilled vancomycin syringes and undertaking a re-audit.

GATA1-mutant clones are frequent and often unsuspected in babies with Down syndrome: identification of a population at risk of leukemia.

Transient abnormal myelopoiesis (TAM), a preleukemic disorder unique to neonates with Down syndrome (DS), may transform to childhood acute myeloid leukemia (ML-DS). Acquired GATA1 mutations are present in both TAM and ML-DS. Current definitions of TAM specify neither the percentage of blasts nor the role of GATA1 mutation analysis. To define TAM, we prospectively analyzed clinical findings, blood counts and smears, and GATA1 mutation status in 200 DS neonates. All DS neonates had multiple blood count and smear abnormalities. Surprisingly, 195 of 200 (97.5%) had circulating blasts. GATA1 mutations were detected by Sanger sequencing/denaturing high performance liquid chromatography (Ss/DHPLC) in 17 of 200 (8.5%), all with blasts >10%. Furthermore low-abundance GATA1 mutant clones were detected by targeted next-generation resequencing (NGS) in 18 of 88 (20.4%; sensitivity ∼0.3%) DS neonates without Ss/DHPLC-detectable GATA1 mutations. No clinical or hematologic features distinguished these 18 neonates. We suggest the term "silent TAM" for neonates with DS with GATA1 mutations detectable only by NGS. To identify all babies at risk of ML-DS, we suggest GATA1 mutation and blood count and smear analyses should be performed in DS neonates. Ss/DPHLC can be used for initial screening, but where GATA1 mutations are undetectable by Ss/DHPLC, NGS-based methods can identify neonates with small GATA1 mutant clones.

Managing and preventing outbreaks of Gram-negative infections in UK neonatal units.

De novo guidance on the management of Gram-negative bacteria outbreaks in UK neonatal units was developed in 2012 by a Department of Health, England Antimicrobial Resistance and Healthcare Associated Infection working group. The recommendations included activation of an organisational response and establishing a control team when an outbreak is suspected; screening for the specific organism only during an outbreak; undertaking multidisciplinary reviews of cleaning routines, hand hygiene and Gram-negative bacteria transmission risks; considering deep-cleaning; cohorting colonised and infected babies preferably but not necessarily in isolation cubicles; and considering reducing beds or closing a unit to new admissions as a way of improving spacing and staff:patient ratios until the outbreak is under control. The group advised establishing mechanisms to communicate effectively across the network; informing parents of the outbreak as early as possible, and providing prewritten 'infection outbreak' information sheets. For prevention of outbreaks, the group advised meeting national staffing and cot-spacing requirements; following a Water Action Plan; using infection reduction care bundles and benchmarking; and introducing breast milk early and limiting antibiotic use.

Perinatal and neonatal mortality in the advent of the neonatal network.

Infant mortality is highest during the neonatal period. The provision of medical care for low birth weight and premature babies is challenging. Neonatal networks aim to improve outcome, optimize efficiency and increase the quality of care for these infants.

Response of steroid-treated former preterm infants to a single dose of meningococcal C conjugate vaccine.

Attenuated antibody responses have been reported in preterm infants who received neonatal dexamethasone treatment. The duration of immunosuppression may extend into later infancy. This study assessed the immune response of former preterm infants to a single meningococcal serogroup C conjugate (MCC) immunisation given after infancy. A cohort of 49 toddlers born at less than 33 weeks' gestation were given an initial dose of MCC vaccine at a median age of 13 months; 11 had received dexamethasone in the neonatal period. Sera obtained 4 weeks post immunisation were analysed for serum bactericidal antibody (SBA) and serogroup C-specific IgG antibody concentrations. Immune responses were compared with those of an historical cohort of 70 term toddlers given a single dose of the same vaccine at age 13 months. An SBA titre of > or =8 was taken to indicate a protective response. Following a single MCC dose, the SBA geometric mean titre (GMT) for former preterm infants was 249 (95% C.I. 111, 558), not significantly different from that of the historical term cohort whose SBA GMT was 141 (95% C.I. 89, 224) (p=0.06). A significantly lower proportion of former preterm infants achieved a protective SBA titre of > or =8 compared with term infants, 37/48 (77%) versus 64/70 (91%), (p=0.03). For steroid-treated and non steroid-treated subgroups, SBA GMTs were 1237 (95% C.I. 250, 6132) and 154 (62, 385), respectively, and numbers achieving an SBA titre of > or =8 were 10/11 (91%) and 27/37 (73%), (p=0.42). Most children born at <33 weeks' gestation mount a protective immune response to a single MCC vaccine dose given at age 13 months, but fewer former preterm infants attain a protective SBA titre of 8 compared with term infants. Previous neonatal dexamethasone treatment does not appear to attenuate immune response after infancy.