Jim Gray

A 7-year study of bloodstream infections in an English children’s hospital

Knowledge of the pattern of bloodstream infection (BSI) can help determine antibiotic prescribing policy and infection control procedures. Data on 2364 consecutive episodes of BSI at Birmingham Children’s Hospital over 7 years were collected prospectively. A total of 1224 (51.8%) episodes were community-acquired, but only 281 (11.9%) were in previously healthy children. Intravascular devices (IVDs) were the most common source of infection, accounting for 48.9% of episodes. Gram-positive, gram-negative and anaerobic bacteria accounted for 66.2%, 31.3% and 0.4% of isolates, and 2.2% were yeasts. Coagulase-negative staphylococci, Staphylococcus aureus and enterococci accounted for over 50% of all isolates. Of these, only enterococci were predominantly hospital-acquired. Neisseria meningitidis was the most common cause of community-acquired BSI in previously healthy children. Of cases of meningococcaemia, 55.6% were diagnosed by PCR alone. Antibiotic resistance, especially in Enterobacteriaceae, S. aureus and enterococci, was more common than in earlier studies of BSI in children, and varied between specialties. The overall mortality rate directly attributable to infection was 2.4%, but was higher in neonates (6.2%) and in previously healthy children with community-acquired infections (5.3%). Conclusion:intravascular devices have emerged as the commonest source of bloodstream infection in children, leading to marked similarities in the species distribution of blood culture isolates across specialties other than General Paediatrics, and explaining the low overall mortality rate. Antibiotic resistance was found frequently in most commonly isolated pathogens, but differences between specialties suggest the existence of local risk factors, some of which might be amenable to infection control interventions.

Successful control of nosocomial transmission of the USA300 clone of community-acquired meticillin-resistant Staphylococcus aureus in a UK paediatric burns centre.

An outbreak of the PVL-positive USA300 clone of community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) occurred in a UK paediatric burns centre from January to February 2010. Four patients, two staff members and one family member of a patient were affected. The outbreak strain had similar antibiotic susceptibilities to other MRSA seen in the hospital, and was only identified when a patient and a staff member presented simultaneously with skin infections. Infection control measures included screening and decolonization of staff and patients, environmental sampling and enhanced cleaning. Isolation of the outbreak strain from an asymptomatic staff member and the environment demonstrates the potential for CA-MRSA to survive and become endemic in UK hospitals.

HIV in the neonate

Mother-to-infant transmission of human immunodeficiency virus (HIV) is a worldwide problem. Between 7 and 40% of infants born to HIV-positive mothers become infected. The prognosis of these infants is poor, with most developing early and rapidly progressive disease. A number of advances in diagnosis and therapy offer opportunities to reduce the rate of vertical transmission and to improve the outlook of infected infants. Antiretroviral therapy during pregnancy and the neonatal period can markedly reduce the risk of mother-to-infant transmission. Recognition that 50% or more of infections are transmitted peripartum offers scope to further reduce the rate of transmission. However there is currently no consensus on the optimal management of pregnancy in HIV-infected women, and there is an urgent need for large randomized controlled trials. The development of polymerase chain reaction and p24 antigen assays has greatly facilitated the diagnosis of neonatal HIV infection, thereby enabling earlier supportive and anti-retroviral therapy. The place of zidovudine in paediatric HIV infection is now well-established, but the future will undoubtedly bring combination anti-retroviral therapy. Optimism about the prospects for developments in the prevention and treatment of paediatric acquired immunodeficiency syndrome must be tempered by the fact that the majority of cases occur in countries where patients have little or no access to medical care.

Antimicrobial Treatment of Serious Gram-Negative Infections in Newborns

The choice of antibiotics for serious Gram-negative bacterial infections in the newborn must balance delivery of effective antibiotics to the site(s) of infection with the need to minimize selection of antibiotic resistance. To reduce the risk of selective pressure from large-scale cephalosporin usage, a penicillin–aminoglycoside combination is recommended as empiric therapy for neonatal sepsis. Where Gram-negative sepsis is strongly suspected or proven, a third-generation cephalosporin should ordinarily replace penicillin. Piperacillin-tazobactam can provide better Gram-negative cover than penicillin–aminoglycoside combinations, without the risk of selecting antibiotic resistance seen with cephalosporins, but further clinical studies are required before this approach to empiric therapy can be recommended. For antibiotic-resistant infections, a carbapenem remains the mainstay of treatment. However, rapid emergence and spread of resistance to these antibiotics means that in the future, neonatologists may have to rely on antibiotics such as colistin, whose pharmacokinetics, safety, and clinical efficacy in neonates are not well-defined.

Infection control: beyond the horizon.

This article will consider possible future directions for innovation and research in infection prevention and control, and will make the case for the importance of including clinical and cost-effectiveness evaluation in such research. Opportunities for studies in a number of broad subject areas will be considered, including prevention and control of existing and emerging infection hazards, the challenges posed by changes in the way that medical care is being delivered, technological developments that could be harnessed for infection prevention and control, how new laboratory diagnostic technologies might benefit infection prevention and control, cleaning and decontamination, and the infection control aspects of hospital design. The need for robust economic data to support the wide and timely implementation of evidence-based practice is emphasized.

Fifteen-minute consultation: the agar plates your microbiology colleagues want you to be scared about

The WHO has recognised antibiotic resistance as one of the greatest threats to human health. As a microbiologist, antibiotic resistance is a problem that keeps me awake at night and inevitably the impact of antibiotic resistance on paediatricians is a matter of when, and not if. I fear for the future of paediatric services such as neonatology, oncology and elective surgery. A recent US study found that 26.8% of post chemotherapy infections and 38.7–50.9% of post-operative infections were caused by bacteria resistant to standard antibiotic prophylaxis. The authors predicted that this will lead to an additional 6300 infection-related deaths in the USA each year. Closer to home, David Cameron commissioned a review into antimicrobial resistance in 2014 and the findings were extremely worrying. The report predicted that by 2050, 10 million annual worldwide deaths will be attributable to antimicrobial resistance. More than annual predicted cancer-associated and diabetes-associated mortality combined. The golden antibiotic era is certainly over. Selecting the most appropriate antibiotic to treat an infection depends on many factors, including route of administration, penetration to site of infection and pathogen susceptibility. Most clinicians do not need an in-depth understanding of bacterial resistance mechanisms as local microbiologists can provide expertise and advice. However, in an era of increasing antibiotic resistance, an insight into the organism factors that affect antibiotic selection can prove useful.