Epidemiology and treatment of painful procedures in neonates in intensive care units.

CONTEXT: Effective strategies to improve pain management in neonates require a clear understanding of the epidemiology and management of procedural pain. OBJECTIVE: To report epidemiological data on neonatal pain collected from a geographically defined region, based on direct bedside observation of neonates. DESIGN, SETTING, AND PATIENTS: Between September 2005 and January 2006, data on all painful and stressful procedures and corresponding analgesic therapy from the first 14 days of admission were prospectively collected within a 6-week period from 430 neonates admitted to tertiary care centers in the Paris region of France (11.3 millions inhabitants) for the Epidemiology of Procedural Pain in Neonates (EPIPPAIN) study. MAIN OUTCOME MEASURE: Number of procedures considered painful or stressful by health personnel and corresponding analgesic therapy. RESULTS: The mean (SD) gestational age and intensive care unit stay were 33.0 (4.6) weeks and 8.4 (4.6) calendar days, respectively. Neonates experienced 60,969 first-attempt procedures, with 42,413 (69.6%) painful and 18,556 (30.4%) stressful procedures; 11,546 supplemental attempts were performed during procedures including 10,366 (89.8%) for painful and 1180 (10.2%) for stressful procedures. Each neonate experienced a median of 115 (range, 4-613) procedures during the study period and 16 (range, 0-62) procedures per day of hospitalization. Of these, each neonate experienced a median of 75 (range, 3-364) painful procedures during the study period and 10 (range, 0-51) painful procedures per day of hospitalization. Of the 42,413 painful procedures, 2.1% were performed with pharmacological-only therapy; 18.2% with nonpharmacological-only interventions, 20.8% with pharmacological, nonpharmacological, or both types of therapy; and 79.2% without specific analgesia, and 34.2% were performed while the neonate was receiving concurrent analgesic or anesthetic infusions for other reasons. Prematurity, category of procedure, parental presence, surgery, daytime, and day of procedure after the first day of admission were associated with greater use of specific preprocedural analgesia, whereas mechanical ventilation, noninvasive ventilation and administration of nonspecific concurrent analgesia were associated with lower use of specific preprocedural analgesia. CONCLUSION: During neonatal intensive care in the Paris region, large numbers of painful and stressful procedures were performed, the majority of which were not accompanied by analgesia.

Screening of glutamate decarboxylase activity and bile salt resistance of human asymptomatic carriage, clinical, food, and environmental isolates of Listeria monocytogenes.

Following consumption, stomach acidity is the first major barrier encountered by the food-borne pathogen Listeria monocytogenes. Analysis of low pH sensitivity and glutamate decarboxylase (GAD) acid resistance system of 14 isolates of L. monocytogenes carried asymptomatically by humans showed that levels of GAD activity were subjected to strain variation. Similar variations were observed for strains responsible for 18 cases of listeriosis, whereas in comparison, 13 strains isolated from food and food-processing plant environments showed lower GAD activity. Following survival of the stomach barrier, L. monocytogenes also has to resist bile salts encountered in the small intestines. Analysis revealed that all strains tested were able to grow in the presence of bile salts with concentrations as high as those encountered in the small intestines and had previously identified bile salt hydrolase (BSH) activity. Strain variation was observed but there was no relationship between the origin of the strains and the ability to degrade bile salts.

Expression of truncated Internalin A is involved in impaired internalization of some Listeria monocytogenes isolates carried asymptomatically by humans.

Fourteen human carriage Listeria monocytogenes isolates were compared to sporadic and epidemic-associated human strains in order to ascertain the pathogenic behavior of these unrecognized asymptomatic strains. Experimental infection of 14-day-old chick embryos revealed that the majority of the carriage strains were attenuated for virulence. Of the 10 attenuated carriage strains, 5 were affected in their invasion capacities in vitro. Western blot analysis with antibody directed against InlA, the surface protein implicated in the internalization in host cells, allowed correlation between the ability of the carriage strains to enter Caco-2 cells and InlA expression. Indeed, these five carriage strains produced truncated forms of InlA. Four of the five truncated forms of InlA had an apparent molecular mass of 47 kDa. In order to assess the existence of a genetic lineage, partial sequences of inlA gene of these four strains were compared and revealed that they had a high degree of sequence conservation at the gene (99.86%) and amino acid (100%) levels. Comparison of their nucleotide sequences with that of the corresponding segment of inlA from EGD-e and Scott A strains, taken as epidemic references, showed more divergence. Taken together, these observations suggest the presence of specific traits that characterize L. monocytogenes strains isolated during asymptomatic carriage. Some of these traits could provide some explanations about the determinants that make them unable to cause systemic human infection.

Assessment of the pathogenic potential of two Listeria monocytogenes human faecal carriage isolates.

Two human faeces carriage isolates of Listeria monocytogenes (H1 and H2) were compared to reference strains (ScottA and LO28) with regard to their lethality in 14-day-old chick embryos, their haemolytic and phospholipase (phosphatidylcholine-phospholipase C and phosphatidylinositol-phospholipase C) activities and their invasiveness towards Caco-2 cells. Experimental infection of chick embryos allowed discrimination of the strains into those exhibiting high virulence (ScottA and H2), those exhibiting slightly attenuated virulence (LO28) and those exhibiting low virulence (H1). A similar percentage mortality and time to death for embryos was observed when they were infected with H2 as was seen with infection by the reference strain ScottA. Therefore, human carriage strain H2 was considered potentially pathogenic. In contrast to H2 and ScottA, H1 exhibited low virulence. Using the tissue-culture cell-line model, it was found that carriage strain H1 was unable to enter Caco-2 cells efficiently, even though it was similar to the virulent strains in terms of the enzymic activities involved in pathogenicity. Detection of the internalins InlA and InlB, involved in the internalization of L. monocytogenes in the host cells, by immunoblot indicated that a truncated form of InlA was produced by H1. Taken together, these data provide a starting point for the study of the behaviour of two types of human faeces carriage strains and their characterization.