Ventilator-associated pneumonia and upper airway colonisation with Gram negative bacilli: the role of stress ulcer prophylaxis in children

OBJECTIVE: To assess the risk of ventilator-associated pneumonia (VAP) and the incidence of upper airway colonisation related to the use of stress ulcer prophylaxis in critically ill children. DESIGN: Retrospective study. SETTING: Paediatric intensive care unit (PICU) of a tertiary care centre. PATIENTS: All children who were mechanically ventilated for more than 48 h. INTERVENTIONS: None. RESULTS: A total of 54 patients were given ranitidine, 53 patients were given sucralfate and 48 patients were given no stress ulcer prophylaxis. Thirteen (8.4%) patients developed VAP: 6 (11.1%) patients in the ranitidine group, 4 (7.5%) in the sucralfate group and 3 (6.2%) in the group without prophylaxis. The rate of upper airway colonisation with Gram negative bacilli was 25.9% (14/54) in the ranitidine group, 22.6% (12/53) in the sucralfate group and 37.5% (18/48) in the group without prophylaxis. The differences among the groups were not significant. CONCLUSIONS: In contrast to findings in adults, we found that, in children, sucralfate does not decrease the incidence of VAP or the incidence of upper airway colonisation with Gram negative bacilli as compared to ranitidine or no stress ulcer prophylaxis. However, the small sample size and study design substantially limit our conclusions.     

Muscarinic receptors on airway mesenchymal cells: Novel findings for an ancient target

Since ancient times, anticholinergics have been used as a bronchodilator therapy for obstructive lung diseases. Targets of these drugs are G-protein-coupled muscarinic M₁, M₂ and M₃ receptors in the airways, which have long been recognized to regulate vagally-induced airway smooth muscle contraction and mucus secretion. However, recent studies have revealed that acetylcholine also exerts pro-inflammatory, pro-proliferative and pro-fibrotic actions in the airways, which may involve muscarinic receptor stimulation on mesenchymal, epithelial and inflammatory cells. Moreover, acetylcholine in the airways may not only be derived from vagal nerves, but also from non-neuronal cells, including epithelial and inflammatory cells. Airway smooth muscle cells seem to play a major role in the effects of acetylcholine on airway function. It has become apparent that these cells are multipotent cells that may reversibly adopt (hyper)contractile, proliferative and synthetic phenotypes, which are all under control of muscarinic receptors and differentially involved in bronchoconstriction, airway remodeling and inflammation. Cholinergic contractile tone is increased by airway inflammation associated with asthma and COPD, resulting from exaggerated acetylcholine release as well as increased expression of contraction related proteins in airway smooth muscle. Moreover, muscarinic receptor stimulation promotes proliferation of airway smooth muscle cells as well as fibroblasts, and regulates cytokine, chemokine and extracellular matrix production by these cells, which may contribute to airway smooth muscle growth, airway fibrosis and inflammation. In line, animal models of chronic allergic asthma and COPD have recently demonstrated that tiotropium may potently inhibit airway inflammation and remodeling. These observations indicate that muscarinic receptors have a much larger role in the pathophysiology of obstructive airway diseases than previously thought, which may have important therapeutic implications.     

Performance of a New Chromogenic Medium,BBL CHROMagar MRSA II (BD), for Detection of Methicillin-Resistant Staphylococcus aureus in Screening Samples

Two chromogenic media for the detection of MRSA were compared: BBL CHROMagar MRSA II (BD) and MRSA ID agar (bioMérieux). Following overnight nonselective enrichment, 1,919 screening samples were inoculated on both chromogenic agars. After 24 h, the sensitivities of both media were high and comparable. Both media showed an important decrease in specificity after 48 h of incubation (decreases of 8% for MRSA II and 10% for MRSA ID), but MRSA II was significantly more specific at both time points.Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial infections worldwide. Infection with MRSA is associated with important clinical and financial implications (7). Screening of high-risk populations and subsequent isolation of carriers are a cost-effective measure to prevent transmission in the hospital, at least if screening results are reliable and readily available (14). A wide range of culture methods and, more recently, molecular methods have been used for MRSA screening (1, 10, 13). Selective media such as mannitol salt agar supplemented with oxacillin have shown limited sensitivity (5) and specificity (4). Broth enrichment culture has been recommended, resulting in a significantly higher yield (15). The incorporation of cefoxitin in culture media has proven to be superior to the incorporation of oxacillin in culture media in the detection of MRSA (12). Recently, chromogenic media became available, permitting the direct detection and identification of MRSA through the presence of specific chromogenic substrates and incorporated antibiotics (6, 8, 9, 11, 12, 16).The purpose of this study was the evaluation of a new chromogenic medium, BBL CHROMagar MRSA II (Becton Dickinson) (hereafter, MRSA II), in comparison to a second, already established chromogenic agar, MRSA ID (bioMérieux), for the detection of MRSA in screening samples after nonselective enrichment. On this new medium, MRSA is visualized as mauve colonies by the presence of a specific chromogenic substate (proprietary formulation) and cefoxitin (5.2 mg/liter). Additional selective agents are added for the inhibition of Gram-negative organisms, yeasts, and other Gram-positive cocci. MRSA II is a modified version of the existing BBL CHROMagar MRSA (cefoxitin, 6 mg/liter). On MRSA ID, MRSA is detected as green colonies through the presence of a chromogenic substrate targeting the α-glucosidase enzyme of S. aureus and cefoxitin (4 mg/liter). Previous studies have shown that MRSA ID is a highly valuable medium for the detection of MRSA, with sensitivities up to 96.4% and specificities up to 99.5% after 24 h of incubation (5, 6, 11).A multicenter prospective evaluation was set up in 5 microbiology laboratories. A total of 1,919 samples submitted for MRSA screening were included, consisting of 588 nares swabs, 394 perianal swabs, 320 throat swabs, 430 pooled swabs (throat, nose, and perianal), and 187 wound swabs. All specimens were enriched overnight in 5 ml nonselective tryptic soy broth (TSB) at 35°C in ambient air. After plating 10 μl of the TSB broth on MRSA II and MRSA ID medium using a three-streak dilution method, all media were incubated at 35°C in ambient air. All plates were read at 24 h and 48 h of incubation, and colony color, size, and growth intensity were scored. Identification of suspicious colonies (characteristic color and morphology) was assessed with at least a coagulase tube test with rabbit plasma or slide agglutination in combination with the detection of DNase. Screening tests for MecA-mediated oxacillin resistance were used according to CLSI guidelines (3). When confirmation tests of suspicious colonies showed no growth of MRSA, the sample was considered false positive. No growth or the absence of suspicious colonies was considered negative. In case of MRSA detection on only one chromogenic medium, the sample was inoculated again on both media starting from TSB to check the reproducibility of the obtained data (n = 8). Quality control testing was successfully performed on each lot of chromogenic media before use in the study (plating a standardized inoculum of ATCC 43300 or ATCC 29213, an in-house methicillin-susceptible S. aureus [MSSA] strain with a cefoxitin MIC of 4 μg/ml).MRSA was detected in 274 samples (14.3%) on one or both chromogenic media (Table ​(Table1).1). There was no difference in sizes and growth intensities of positive colonies on both chromogenic media. After 24 h, MRSA was detected in 261 samples on MRSA II and in 257 samples on MRSA ID. After 48 h, 271 samples were positive on MRSA II and 269 on MRSA ID. This resulted in comparable sensitivities after 24 h of incubation for MRSA II and MRSA ID (95.3% and 93.8%, respectively; McNemar P = 0.42) as well as after 48 h (98.9% and 98.2%, respectively; McNemar P = 0.72). For both chromogenic media, the sensitivities were significantly higher after 48 h of incubation versus 24 h of incubation (MRSA II, P = 0.002; MRSA ID, P = 0.0005). However, when we excluded the results of one center, we observed nearly identical sensitivities after 24 and 48 h of incubation (98.3% and 99.1%, respectively, for MRSA II, P = 0.5; 97.8% and 99.1%, respectively, for MRSA ID, P = 0.25), with a positivity rate of 13.2% in 1,759 samples. This one center included 160 samples (positivity rate of 26.2%), with significantly higher sensitivities for both chromogenic media after 48 h compared to 24 h. Sensitivity for MRSA II increased from 78.5% to 95.2% (P = 0.0078), and that for MRSA ID increased from 71.4 to 92.8% (P = 0.0039). It was stressed that the same procedure was followed in the 5 centers, with extra care for a complete 24-h incubation before the first reading of the chromogenic agars. However, this center reported a possible too cautious early assignment of suspected colonies after 24 h, as they use selective instead of TSB enrichment in their daily routine.

TABLE 1.

Number of MRSA strains isolated from 1,919 screening samples

Monitoring and discussing health-related quality of life in adolescents with type 1 diabetes improve psychosocial well-being: a randomized controlled trial

OBJECTIVE—To test the effects of monitoring and discussing of health-related quality of life (HRQoL) in adolescents with type 1 diabetes in a multicenter randomized controlled trial.RESEARCH DESIGN AND METHODS—Four centers were randomly assigned to the HRQoL intervention (46 adolescents) or control (45 adolescents) group, with three regular visits scheduled within 12 months in both groups. In the HRQoL intervention group, HRQoL of adolescents was assessed using the Pediatric Quality of Life Inventory, and outcomes were discussed face-to-face during the consultation. The control group received care as usual. Mean differences between the groups at 12 months in physical and psychosocial well-being (Child Health Questionnaire [CHQ]-CF87/PF50, Diabetes-Specific Family Conflict Scale, and Center for Epidemiological Studies Scale for Depression), satisfaction with care (Patients’ Evaluation of the Quality of Diabetes Care), and A1C were determined, controlling for baseline scores.RESULTS—Mean scores on the CHQ subscales of psychosocial health (P < 0.001), behavior (P < 0.001), mental health (P < 0.001), and family activities (P < 0.001) improved in the HRQoL intervention group, except for adolescents with the highest A1C values. Adolescents in the HRQoL intervention group reported higher self-esteem (CHQ) at follow-up (P = 0.016), regardless of A1C, and were more satisfied with care (P = 0.009) than control subjects. No significant differences between the two groups over time were observed in A1C levels.CONCLUSIONS—Periodic monitoring and discussion of HRQoL in adolescents with diabetes is appreciated and has positive effects on their psychosocial well-being, except for those in poorest control.Hormonal and psychosocial changes related to puberty can seriously complicate diabetes regulation. Indeed, adolescents with type 1 diabetes as a group display the worst glycemic control compared with other age-groups (1,2). From a developmental perspective, the daily demands of self-regulation can interfere with adolescents’ normal routines and friendships, thereby compromising their emotional and social well-being (3). Moreover, teenagers tend to give high priority to fulfilling their psychosocial needs here and now rather than taking preventive action to avoid health risks long term (4). Attaining good health-related quality of life (HRQoL) as well as strict glycemic control is a challenge for adolescents with diabetes, their families, and health care providers.Periodic evaluation and discussion of the adolescents’ HRQoL as an integral part of diabetes care is recommended to ensure recognition of the teenagers’ perspective, identify psychosocial barriers, and promote healthy coping (5,6). The utility of such an approach has not been tested in pediatric diabetes, but was shown to be beneficial in pediatric rheumatic patients as well as adult diabetes and cancer patients (7–9). We set out to test the effects of systematic monitoring and discussion of HRQoL of adolescents with type 1 diabetes in a randomized controlled trial. We hypothesized this would have a positive effect on the well-being and satisfaction with care of the adolescents, subsequently improving self-care and glycemic control.     

Evaluation of 99mTc-dichloro bis (1,2-dimethylphosphino) ethane (99mTc-DMPE) for myocardial scintigraphy in man

^99mTc-DMPE was used for myocardial scintigraphy in ten patients with coronary artery disease. As in ²⁰¹Tl studies regional activity of ^99mTc-DMPE was reduced in infarcted myocardium. However, activity accumulation of ^99mTc-DMPE in the heart was faint, while that in the liver was prominent. The activity ratio of heart to liver improved with time, whereas that of heart to lung decreased. The scintigraphic quality was considerably worse in ^99mTc-DMPE studies than in those with ²⁰¹Tl, due to high background activity. Also the visualization of the ribs and sternum interfered with the interpretation of the scintigrams. From these results it appears that ²⁰¹Tl remains still the agent of choice for myocardial perfusion scintigraphy.