Aodhan Breathnach

Risk factors for late onset gram-negative infections: a case–control study

Objectives To determine the incidence, mortality and risk factors for neonatal late onset gram-negative sepsis and meningitis (LOGNS). Design Retrospective case–control study. Setting Tertiary neonatal unit in London. Patients Consecutive inborn infants with late onset (>48 h of life) invasive gram-negative infections diagnosed between 1999 and 2005. Controls were healthy infants matched for gestation and time of admission to the neonatal unit. Main outcome measures Clinical and risk factor data. Results 73 cases of LOGNS were identified of which 48 were inborn and included in the study (incidence 1.85/1000 live births). Enterobacter spp. (28%), Escherichia coli (27%) and Klebsiella spp. (21%) were the most common pathogens. The majority of infants were of very low birthweight (VLBW; 79%), and cases and controls were well matched (median gestation 26 weeks). Overall case death was 27% in cases versus 13.5% in controls (p=0.08). There was no significant difference between cases and controls regarding maternal risk factors. Mechanical ventilation, total parenteral nutrition (TPN) and its duration, presence of a central venous line and its duration, use of specific antibiotics and the occurrence of necrotising enterocolitis at or before the first positive culture were all significantly associated with case status in univariate analysis. In multivariate logistic regression analysis, only duration of TPN at or before first positive blood culture remained independently associated with LOGNS (p<0.001). Conclusions LOGNS occurs predominantly in VLBW infants. When the influence of gestational age is accounted for, the only independent risk factor found for late onset gram-negative neonatal infections is the duration of TPN.

Prevalence of nasopharyngeal carriage of pneumococcus in preschool children attending day care in London

Objective: To estimate the prevalence of nasopharyngeal (NP) carriage of pneumococcus (Streptococcus pneumoniae) and describe the antibiotic resistance patterns and serotypes in young children attending group day care in London. Design and subjects: Cross-sectional survey of attendees at a sample of registered child day care centres (CDCCs) in a London borough. Setting: Urban setting with a socially and culturally diverse population. Methods and outcomes: 19 CDCCs (13% of total) participated between March and November 2003. A single NP swab was required from each child, and parents completed a questionnaire about their child’s health and attendance at day care. WHO methodology for pneumococcal carriage studies was followed. Results: 30% of parents consented. 234 swabs were collected from children aged 6 months to 5 years. 53% were boys and 81% were white. 120 children (51%, 95% CI 45% to 58%) carried pneumococci in their nasopharynx. None of the isolates were resistant to penicillin (upper CL 3%). 21 isolates were resistant to erythromycin (17.5%, 95% CI 11% to 25.5%). 68 isolates (57%) were serotypes included in the 7-valent conjugate vaccine. Non-white children had a lower prevalence of carriage (27% vs 58%). Conclusion: The prevalence of pneumococcal NP carriage was high. The penicillin resistance rate is lower than in many other countries and may reflect a decrease in community antibiotic prescribing in the UK. Monitoring circulating serotypes is important in the context of recent changes to the vaccination policy. Further study is required to explore the association with ethnicity and risk factors for antibiotic resistance.

Trends in paediatric nosocomial bacteraemia in a London tertiary hospital

To describe the incidence and microbiological characteristics of nosocomial bloodstream infections in childhood over a 9‐year period at a South London tertiary hospital.

Hospital-acquired bacteraemia among children admitted to a london tertiary hospital as a measurement of neonatal and paediatric healthcare-associated infection

Background Hospital-acquired infections are associated with significant morbidity and mortality because they are often caused by multi-resistant pathogens and usually affect children with serious underlying medical conditions. Objectives To describe trends in hospital-acquired bacteraemia (HAB) among children aged <16 years admitted to a London tertiary hospital between 2001 and 2009 inclusive. Methods A standard proforma is used by clinical microbiologists for the management of significant bacteraemia in patients admitted to St. Georges Hospital, London. Bacteraemia was considered to be hospital-acquired if the blood culture was taken at least 72 h after hospital admission in a child with clinical symptoms, signs and/or laboratory markers consistent with infection. Results There were 478 episodes of HAB over the 9-year period, including 254 episodes (53.1%) in the Neonatal Intensive Care Unit (NICU). Gram-positive pathogens were responsible for 71 and 76% of episodes in NICU and the paediatric wards, respectively. HAB fell by 71% in NICU from 8.7 to 2.6 episodes/100 discharges (p<0.0001) and by 61% in the paediatric medical wards, from 0.70 to 0.27 episodes/100 discharges (p<0.0001) in 2001–2005 and 2006–2009, respectively. These reductions were mainly related to a decline in line-related staphylococcal bacteraemia following the introduction of guidance on safer insertion and handling of central and peripheral catheters aimed at reducing the burden of methicillin-resistant Staphylococcus aureus infections. Conclusions The vast majority of HAB in children are associated with line infections, which can be prevented through implementation of appropriate infection control strategies. Rates of HAB are relatively easy to obtain and, after adjustment for case-mix, could be used as part of a national neonatal and paediatric nosocomial infection surveillance programme.

Abnormal phagocytic function in children under one year of age

The action of white blood cells (WBC) against Proteus mirabilis was assayed in 22 children following meningitis or septicaemia and compared with that in control groups of: (1) adult volunteers, (2) children undergoing minor surgical procedures for non-infective conditions, and (3) children being investigated for suspected renal disease. WBC bacterial killing tests were normal in all 55 adult volunteers. Abnormal results were obtained in 11 of 22 (50%) children with meningitis or septicaemia, 10 of 21 (47.6%) children undergoing surgery and six of 13 (46%) children with suspected renal disease, thereby indicating that there were no significant differences in phagocytic function among these three groups. Of children aged 1 year or less, 75% had abnormal phagocytic function. The significance of this finding is discussed.