Clinical Practice Guidelines for Clostridium difficile Infection in Adults and Children: 2017 Update by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA)

A panel of experts was convened by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) to update the 2010 clinical practice guideline on Clostridium difficile infection (CDI) in adults. The update, which has incorporated recommendations for children (following the adult recommendations for epidemiology, diagnosis, and treatment), includes significant changes in the management of this infection and reflects the evolving controversy over best methods for diagnosis. Clostridium difficile remains the most important cause of healthcare-associated diarrhea and has become the most commonly identified cause of healthcare-associated infection in adults in the United States. Moreover, C. difficile has established itself as an important community pathogen. Although the prevalence of the epidemic and virulent ribotype 027 strain has declined markedly along with overall CDI rates in parts of Europe, it remains one of the most commonly identified strains in the United States where it causes a sizable minority of CDIs, especially healthcare-associated CDIs. This guideline updates recommendations regarding epidemiology, diagnosis, treatment, infection prevention, and environmental management.

Clinical Practice Guidelines for Clostridium difficile Infection in Adults and Children: 2017 Update by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA)

A panel of experts was convened by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) to update the 2010 clinical practice guideline on Clostridium difficile infection (CDI) in adults. The update, which has incorporated recommendations for children (following the adult recommendations for epidemiology, diagnosis, and treatment), includes significant changes in the management of this infection and reflects the evolving controversy over best methods for diagnosis. Clostridium difficile remains the most important cause of healthcare-associated diarrhea and has become the most commonly identified cause of healthcare-associated infection in adults in the United States. Moreover, C. difficile has established itself as an important community pathogen. Although the prevalence of the epidemic and virulent ribotype 027 strain has declined markedly along with overall CDI rates in parts of Europe, it remains one of the most commonly identified strains in the United States where it causes a sizable minority of CDIs, especially healthcare-associated CDIs. This guideline updates recommendations regarding epidemiology, diagnosis, treatment, infection prevention, and environmental management.

Clostridium difficile infection is associated with increased risk of death and prolonged hospitalization in children

BACKGROUND

Clostridium difficile infection (CDI) is associated with significant morbidity and mortality among adults. However, outcomes are poorly defined among children.

METHODS

A retrospective cohort study was performed among hospitalized children at 41 children's hospitals between January 2006 and August 2011. Patients with CDI (exposed) were matched 1:2 to patients without CDI (unexposed) based on the probability of developing CDI (propensity score derived from patient characteristics). Exposed subjects were stratified by C. difficile test date, suggestive of community-onset (CO) versus hospital-onset (HO) CDI. Outcomes were analyzed for matched subjects.

RESULTS

We identified 5107 exposed and 693 409 unexposed subjects. Median age was 6 years (interquartile range [IQR], 2-13 years) for exposed and 8 years (IQR, 3-14 years) for unexposed subjects. Of these, 4474 exposed were successfully matched to 8821 unexposed by propensity score. In-hospital mortality differed significantly (CDI, 1.43% vs matched unexposed, 0.66%; P < .001). Mortality rates were similar between CO-CDI and matched subjects. However, mortality rates were significantly greater among HO-CDI compared with matched unexposed (odds ratio, 6.73 [95% confidence interval {CI}, 3.77-12.02]). Mean differences in length of stay (LOS) and total cost were significant: 5.55 days (95% CI, 4.54-6.56 days) and $18 900 (95% CI, $15 100-$22 700) for CO-CDI, and 21.60 days (95% CI, 19.29-23.90 days) and $93 600 (95% CI, $80 000-$107 200) for HO-CDI.

CONCLUSIONS

Pediatric CDI is associated with increased mortality, longer LOS, and higher costs. These findings underscore the importance of antibiotic stewardship and infection control programs to prevent this disease in children.

Clostridium difficile Infection in children

Clostridium difficile is the most common cause of health care-associated diarrhea among adults in the United States and is associated with significant morbidity and mortality. During the past decade, the epidemiology of C difficile infection (CDI) has changed, including a rise in the rate and severity of infection related to the emergence of a hypervirulent strain as well as an increase in disease among outpatients in community settings. Although less is known about CDI among pediatric patients, C difficile is increasingly recognized as an important pathogen among children. In this review, we discuss recent updates in the incidence and epidemiology of CDI among children, including risk factors for infection, and highlight the importance of CDI in special populations of children, particularly those with inflammatory bowel disease or cancer. In addition, we review current knowledge in the areas of diagnosis and management of CDI among children and highlight future areas for research.

The role of BMP-6, IL-6, and BMP-4 in mesenchymal stem cell-dependent bone development: effects on osteoblastic differentiation induced by parathyroid hormone and vitamin D(3)

Human bone marrow-derived mesenchymal stem cells (MSCs) represent an ideal source for cell therapy for inherited and degenerative diseases, bone and cartilage repair, and as target for gene therapy. The role of the combination of human parathyroid hormone (PTH) and vitamin D(3) in bone formation and mineralization has been established in several osteoblast cell culture studies. The aim of the present study was to evaluate the role of this hormonal combination alone and in the presence of bone morphogenetic protein-4 (BMP-4) or-6 (BMP-6) in inducing osteogenic differentiation of human MSC. Human MSC derived from adult normal bone marrow that are positive for CD29, CD44, CD105, and CD166 and negative for CD14, CD34, and CD45, were treated with the PTH and 1,25-dihydroxyvitamin D(3) in the presence and absence of recombinant human BMP-4 or BMP6. PTH and vitamin D(3) induced high levels of expression of two key markers of bone formation: osteocalcin and alkaline phosphatase by MSCs. BMP-6 but not BMP-4 increased osteocalcin expression induced by PTH and vitamin D(3). Both BMPs enhanced calcium formation in MSC cultures and this response was potentiated by PTH and vitamin D(3). The present results revealed a novel potent effect of PTH and vitamin D(3) plus BMPs in inducing bone development by human MSCs. These results may facilitate therapeutic utility of MSCs for bone disease and help clarify mechanisms involved in stem cell-mediated bone development.

Ventilator-Associated Events in Neonates and Children--A New Paradigm

OBJECTIVES

To identify a pediatric ventilator-associated condition definition for use in neonates and children by exploring whether potential ventilator-associated condition definitions identify patients with worse outcomes.

DESIGN

Retrospective cohort study and a matched cohort analysis.

SETTING

Pediatric, cardiac, and neonatal ICUs in five U.S. hospitals.

PATIENTS

Children 18 years old or younger ventilated for at least 1 day.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We evaluated the evidence of worsening oxygenation via a range of thresholds for increases in daily minimum fraction of inspired oxygen (by 0.20, 0.25, and 0.30) and daily minimum mean airway pressure (by 4, 5, 6, and 7 cm H2O). We required worsening oxygenation be sustained for at least 2 days after at least 2 days of stability. We matched patients with a ventilator-associated condition to those without and used Cox proportional hazard models with frailties to examine associations with hospital mortality, hospital and ICU length of stay, and duration of ventilation. The cohort included 8,862 children with 10,209 hospitalizations and 77,751 ventilator days. For the fraction of inspired oxygen 0.25/mean airway pressure 4 definition (i.e., increase in minimum daily fraction of inspired oxygen by 0.25 or mean airway pressure by 4), rates ranged from 2.9 to 3.2 per 1,000 ventilator days depending on ICU type; the fraction of inspired oxygen 0.30/mean airway pressure 7 definition yielded ventilator-associated condition rates of 1.1-1.3 per 1,000 ventilator days. All definitions were significantly associated with greater risk of hospital death, with hazard ratios ranging from 1.6 (95% CI, 0.7-3.4) to 6.8 (2.9-16.0), depending on thresholds and ICU type. Each definition was associated with prolonged hospitalization, time in ICU, and duration of ventilation, among survivors. The advisory board of the study proposed using the fraction of inspired oxygen 0.25/mean airway pressure 4 thresholds to identify pediatric ventilator-associated conditions in ICUs.

CONCLUSIONS

Pediatric patients with ventilator-associated conditions are at substantially higher risk for mortality and morbidity across ICUs, regardless of thresholds used. Next steps include identification of risk factors, etiologies, and preventative measures for pediatric ventilator-associated conditions.

Reducing catheter-associated urinary tract infections: a quality-improvement initiative

BACKGROUND

Catheter-associated urinary tract infections (CAUTIs) are among the most common health care-associated infections in the United States, yet little is known about the prevention and epidemiology of pediatric CAUTIs.

METHODS

An observational study was conducted to assess the impact of a CAUTI quality improvement prevention bundle that included institution-wide standardization of and training on urinary catheter insertion and maintenance practices, daily review of catheter necessity, and rapid review of all CAUTIs. Poisson regression was used to determine the impact of the bundle on CAUTI rates. A retrospective cohort study was performed to describe the epidemiology of incident pediatric CAUTIs at a tertiary care children's hospital over a 3-year period (June 2009 to June 2012).

RESULTS

Implementation of the CAUTI prevention bundle was associated with a 50% reduction in the mean monthly CAUTI rate (95% confidence interval: -1.28 to -0.12; P = .02) from 5.41 to 2.49 per 1000 catheter-days. The median monthly catheter utilization ratio remained unchanged; ∼90% of patients had an indication for urinary catheterization. Forty-four patients experienced 57 CAUTIs over the study period. Most patients with CAUTIs were female (75%), received care in the pediatric or cardiac ICUs (70%), and had at least 1 complex chronic condition (98%). Nearly 90% of patients who developed a CAUTI had a recognized indication for initial catheter placement.

CONCLUSIONS

CAUTI is a common pediatric health care-associated infection. Implementation of a prevention bundle can significantly reduce CAUTI rates in children.

Diagnosis and Management of Clostridium difficile Infection by Pediatric Infectious Diseases Physicians

BACKGROUND

The incidence of C difficile infection (CDI) has risen among children; however, optimal management of CDI within a diverse pediatric population remains unclear. Although adult guidelines recommend oral vancomycin for treatment of second recurrence or severe CDI, dedicated pediatric data to support pediatric specific management guidelines are lacking. Our objective was to describe current CDI management practices by pediatric infectious diseases (ID) physicians.

METHODS

We surveyed pediatric members of the Emerging Infections Network, a network of infectious diseases (ID) physicians across North America, in October 2012. Clinical vignettes were used to determine how physicians modify CDI management based on clinical presentation or presence of comorbidities, including solid organ transplantation, inflammatory bowel disease, and neutropenia.

RESULTS

Of the 285 physicians surveyed, 167 (59%) responded. There were no significant differences in geography, level of experience, or hospital type between respondents and non-respondents. All respondents (100%) used oral metronidazole for the initial occurrence of mild CDI in a normal host. Management varied substantially for mild CDI in patients with a variety of comorbidities, in whom metronidazole therapy was less frequently preferred (41-79%). For management of severe CDI, 65% preferred oral vancomycin alone or in combination with at least one other agent. For a second recurrence, oral vancomycin alone or in combination was preferred by 92%. Among 125 respondents who reported using alternative therapies for recurrent or severe CDI, 23 (18%) recommend fecal microbiota transplantation, while 20 (16%) reported using fidaxomicin.

CONCLUSIONS

Pediatric ID physicians prefer metronidazole for treatment of mild CDI in healthy children, but management strategies vary for patients with comorbidities or recurrent or severe disease. These findings highlight the need for pediatric comparative effectiveness studies aimed at determining the optimal treatment for pediatric CDI.

Retinoic acid suppresses interleukin 6 production in normal human osteoblasts

Systemic long-term retinoid therapy for chronic skin diseases significantly reduced bone turnover markers within days and led to bone abnormalities. Retinoic acid (RA) plays a key role in the regulation of mouse bone cell proliferation, differentiation and functions. Meanwhile, there is little information of RA effect on human osteoblast and osteoclast cell development and function. Interleukin 6 (IL-6) is a pleiotropic cytokine with profound effects on bone metabolism. Thus, the present study examined the RA effect on cell differentiation, alkaline phosphatase and osteocalcin production as well as IL-6 production in normal human osteoblasts. The number of large differentiated osteoblast cells decreased in RA-treated cultures P<0.05. The production of bone specific markers, alkaline phosphatase and osteocalcin, was also reduced in RA-treated cultures. Normal human osteoblasts produced 31.0+/-4.8 pg IL-6 per ml in control cultures. Within 24 h, RA at all four concentrations reduced Il-6 production from normal human osteoblasts. The pharmacological concentration of 10(-5) M RA suppressed 90% of IL-6 production. The present study shows for the first time that RA profoundly inhibits IL-6 production in normal human osteoblasts within 24 h and in a dose-dependent manner. RA was shown previously to inhibit IL-6 production in several other normal and malignant human cell types. The associated decrease in osteoblast cell differentiation, alkaline phosphatase and osteocalcin production could result from the rapid RA-inhibition of IL-6 production. Thus, RA inhibition of IL-6 production in normal human osteoblasts may contribute to the bone abnormalities seen after systemic long-term retinoid therapy in some patients.

Effect of bone morphogenetic protein-6 on haemopoietic stem cells and cytokine production in normal human bone marrow stroma

Normal human bone marrow stroma cells include stem cells for both haemopoietic and osteochondrogenic lineages and express both bone morphogenetic protein (BMP) type I and type II receptors. As a member of the TGF-beta super-family, BMP-6 binds to both BMP type I and type II receptors and is involved in the developmental processes of renal and hepatic systems as well as of human foetal intestine. Also, BMP-6 induces osteoblastic differentiation of pluripotent mesenchymal cells and is an autocrine stimulator of chondrocyte differentiation. The present study was carried out to investigate the effect of BMP-6 on human cobblestone-area-forming cells (CAFC), that represent the functional primitive repopulating haemopoietic stem cell in long-term bone marrow culture. Also, the effect of BMP-6 on marrow stroma production of interleukin-6, -11 and their common receptor gp130 that is expressed in haemopoietic stem cells and is indispensable for their proliferation and tri-lineage differentiation was examined. Moreover, the effect of BMP-6 on marrow stroma release of soluble adhesion molecule VCAM-1 mediating the primitive haemopoietic stem cell adhesion to marrow stroma was examined. The number of CAFC was significantly reduced after BMP-6 treatment from 88+/-10 per 10(5)cells in control cultures in a dose dependent manner to only 48+/-3 per 10(5)cells in 50 ng/ml BMP-6-treated cultures, P< 0.01. Quantitative ELISA measurement revealed 50 ng/ml BMP-6 was able to significantly reduce IL-6 and IL-11 production from marrow stroma, P< 0.01. Also, BMP-6 significantly increased soluble gp130 release by 7.4-fold in 50 ng/ml BMP-6-treated marrow stroma cultures. The profound rapid increase in this natural antagonist of human IL-6 cytokine family may reduce the gp130 signaling. Also, the soluble VCAM-1 released increased by two-fold in 50 ng/ml BMP-6-treated marrow stroma cultures. The marked increase in the soluble form may exert an antagonist effect on the function of VCAM-1 (ligand for VLA4). Recently, blocking the VLA4/VCAM-1 adhesion pathway was shown to mobilise haemopoietic CD34 positive cells in normal individuals. Also, we previously observed a significantly lower expression of VLA4 (CD49d) on G-CSF-mobilised blood CD34 positive cells than on bone marrow CD34 positive cells before mobilisation in the same normal donors. Since BMP are currently being used in clinical trials for bone repair and fracture healing, the present results suggest a possible role for BMP-6 in mobilising CD34 positive cells for transplantation. Further in vitro tests are required to evaluate this potential mobilising role of BMP-6 in human long-term bone marrow culture.

Divergent effect of taxol on proliferation, apoptosis and nitric oxide production in MHH225 CD34 positive and U937 CD34 negative human leukaemia cells

Paclitaxel (Taxol) has been shown to be clinically effective in treatment of patients with breast and ovarian cancer. It has also shown promising results in various other solid tumours. Paclitaxel has induced apoptosis in the G2/M phase of the cell cycle in both HL-60 and U937 human leukaemia cells. A recent study has shown a dose-dependent cytotoxicity for both taxanes: paclitaxel (taxol) and docetaxel (Taxotere) on fresh leukaemia cells in primary culture from 16 ALL and four AML patients and proposed their use in treatment of acute leukaemia patients. AML is a heterogeneous disease in which malignant transformation and disease progression occur at the level of CD34 positive cells. Also, the multi-drug resistance gene product, P-glycoprotein is expressed only in CD34 positive AML cells. Therefore, an in vitro evaluation of the efficacy of paclitaxel, a P-glycoprotein substrate, in CD34 positive AML cells is warranted before considering its clinical use in acute leukaemia patients. Since all in vitro studies of paclitaxel reported so far have involved only CD34 negative (HL-60, U937, K562) human AML cells, the aim of the present study was to evaluate paclitaxel efficacy against CD34 positive AML cells. The IC50 of paclitaxel for apoptosis was significantly higher in MHH225 CD34 positive cells (12 +/- 2 microM) than in U937 CD34 negative cells (1.7 +/- 0.2 microM), P < 0.001. Paclitaxel has a significantly weaker cytotoxic effect on CD34 positive AML cells. One log higher concentration of paclitaxel was required in MHH225 CD34 positive AML cells to achieve the same apoptosis level achieved in U937 CD34 negative leukaemia cells. Also, at the high concentration achievable in vivo: 10 microM paclitaxel, only half the MHH225 CD34 positive AML cells were apoptotic versus 72% of U937 CD34 negative leukaemia cells. Clearly, paclitaxel has only weak or modest in vitro efficacy compared with several conventional anti-leukaemia drugs used in AML treatment. The present results support the poor level of in vivo induction of apoptosis achieved during a phase I clinical study with paclitaxel therapy in 26 leukaemia patients. Also, the present results have shown a significant increase in nitric oxide production during paclitaxel-induced apoptosis in U937 monocytic leukaemia cells, confirming the vital role of nitric oxide in mediating paclitaxel-induced apoptosis by monocytic cells. In conclusion, the present study has demonstrated a clear difference between the effect of paclitaxel on CD34 negative and CD34 positive AML cells. Given its poor performance in the phase I clinical study of 26 acute leukaemia patients and the present weak in vitro cytotoxic effect, it is unlikely that paclitaxel will have a role in the treatment of acute leukaemia. Also, the present study emphasises the need to use CD34 positive AML cells such as MHH225 rather than the unsuitable lineage-specific CD34 negative cells such as HL-60 or U937 for in vitro pre-clinical screening of potential novel effective anti-leukaemia agents.

Variation in Risk of Hospital-Onset Clostridium difficile Infection Across β-Lactam Antibiotics in Children With New-Onset Acute Lymphoblastic Leukemia

BACKGROUND

Antibiotic exposure is common among children with leukemia. However, limited data exist regarding the risk of Clostridium difficile infection (CDI) across anti-pseudomonal β-lactam antibiotics commonly used for fever and neutropenia.

METHODS

A multicenter cohort of children with newly diagnosed acute lymphoblastic leukemia (ALL) was established from 43 freestanding children's hospitals from 1999 to 2009. Patients were followed until their index CDI event, defined by the CDI ICD-9 code plus a C difficile test charge, or until 180 days from ALL diagnosis. Cox proportional hazards models were performed to identify the hazards of CDI after exposure to anti-pseudomonal β-lactams, adjusting for demographics, other antibiotic exposures, severity of illness, antacids, gastrointestinal manipulation, and confounding by hospital.

RESULTS

A cohort of 8268 ALL patients was assembled; median age was 5.5 years (interquartile range, 3.26-10.58). Two-hundred sixty-eight (3.2%) patients developed CDI within 180 days of ALL diagnosis. Each 1-day increase in exposure to an anti-pseudomonal β-lactam within the prior 30 days was associated with a significantly increased risk for CDI (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.01, 1.09). Ceftazidime (HR, 1.05; 95% CI, 1.02, 1.08) and cefepime (HR, 1.07; 95% CI, 1.02, 1.12) were each independently associated with CDI.

CONCLUSIONS

Efforts to reduce total exposure to anti-pseudomonal β-lactam agents may help to reduce the risk of CDI in children with newly diagnosed ALL. Cefepime and ceftazidime were independently associated with CDI, whereas anti-pseudomonal penicillins and carbapenems were not. These findings, if confirmed, have potential implications for antibiotic choice during periods of fever and neutropenia.

Mechanisms mediating the inhibitory effect of all-trans retinoic acid on primitive hematopoietic stem cells in human long-term bone marrow culture

All-trans retinoic acid (RA) has generally been found to stimulate late committed (colony-forming unit- granulocyte, macrophage [CFU-GM]) and inhibit early (CFU-Blast) normal human myeloid progenitor cells. The present study provides the first evidence that the pharmacological concentration of 1 microM RA, exerts an inhibitory effect on the proliferation of functional human primitive hemopoietic stem cells (cobblestone area-forming cell [CFAC]) in long-term bone marrow cultures. Treatment of four-week confluent bone marrow culture with 1 microM RA for five days significantly reduced week 4 CAFC from 88 +/- 10 in control cultures to only 52 +/- 12 per 10(5) cells, p < 0.01. Quantitative enzyme-linked immunosorbent assay measurement of interleukin 6 (IL-6) and IL-11 produced from the four-week bone marrow stroma culture revealed only a slight and moderate increase of IL-6 and IL-11 production after treatment with RA. On the other hand, treatment with RA profoundly increased the soluble receptor gp130 released from the four-week bone marrow stroma by 7.5-fold from only 145 +/- 2.1 pg per ml in control cultures to 1,069.9 +/- 3.8 pg per ml in RA-treated cultures. A similar marked increase in the soluble adhesion molecules ICAM-1, and to a lesser extent VCAM-1, released from the four-week bone marrow stroma was observed after RA treatment. IL-6 has been implicated in the inhibitory effect of RA in several human hemopoietic and nonhemopoietic cells. The common transducing signal chain gp130, for all receptors of the IL-6 cytokine family, is expressed in most primitive human hemopoietic CD34(+) cells and its signaling was shown to synergize with other hemopoietic cytokines to expand primitive human hemopoietic stem cells. Recently, soluble gp130 was shown to be a natural potent antagonist of the human IL-6 cytokine family by binding the ligand and thereby reducing its bioavailability. The profound and rapid 7.5-fold increase in the natural antagonist of human IL-6 cytokine family after RA treatment could abrogate the gp130 signaling required for proliferation and/or expansion of human primitive hemopoietic stem cells and lead to the observed inhibitory effect of RA on CAFC. Both adhesion molecules VCAM-1 and ICAM-1 mediate human hemopoietic stem cell adhesion to marrow stroma. The present significant increase in the soluble form of these adhesion molecules after RA treatment could exert a significant antagonist effect on their function and hence may impair CAFC adhesion to marrow stroma. In conclusion, the RA inhibitory effect on the proliferation of primitive human hemopoietic stem cells could be mediated through: A) an impaired hemopoietic stem cell adhesion due to the significant increase in soluble adhesion molecules released from the marrow stroma after RA treatment, and B) a significantly reduced gp130 signaling that is necessary for stem cell proliferation due to the natural antagonistic effect of the profoundly increased level of soluble gp130 released from the marrow stroma after treatment with RA.

Effect of all-trans retinoic acid on chemotherapy induced apoptosis and down-regulation of Bcl-2 in human myeloid leukaemia CD34 positive cells

Acute myeloid leukaemia (AML) is a heterogeneous malignant disease in which disease progression at the level of CD34 positive cells has a major impact in drug resistance and relapse. The multi-drug resistance (MDR1) gene product, P-glycoprotein is expressed mainly in CD34 positive AML cells and Bcl-2 is expressed simultaneously with several putative drug resistance parameters in these cells. Bcl-2 over-expression is associated with CD34 positivity, poor response to chemotherapy and reduced overall survival in AML patients. Recently, all-trans retinoic acid (RA) has been reported to enhance cytarabine-induced apoptosis and downregulate Bcl-2 in several human myeloid leukaemia CD34 negative cells. The two CD34 positive human myeloid leukaemia cell lines: KG1 and KGla have the unique feature of expressing significant functional P-glycoprotein. Thus, the efficacy of RA in enhancing cytrabine- and fludarabine-induced apoptosis and overcoming the resistance was examined in both KG1 (CD34+CD7-) and KGla (CD34+CD7+) human myeloid leukaemia cells in the present study. Both cytarabine and fludarabine induced a dose dependent increase in the number of apoptotic cells in both CD34 positive cell types. Interestingly, the cytarabine-induced apoptosis was significantly more than fludarabine-induced apoptosis in both cell types. All-trans RA alone failed to induce apoptosis or inhibit proliferation of either of the two human CD34 positive leukaemia cell types. However, RA enhanced cytarabine- or fludarabine-induced apoptosis and inhibition of proliferation in KG1 CD34+CD7- but not in KGla CD34+CD7+ myeloid leukaemia cells. As single agents, RA, cytarabine and fludarabine reduced Bcl-2 expression in a dose dependent manner in both cell types. Using a quantitative ELISA assay, the Bcl-2 protein concentration was reduced by 86 or 100%, after 72 h of treatment with 10 microM cytarabine or fludarabine, respectively, in both CD34 positive leukaemia cell types. The addition of RA to cytarabine enhanced its induced reduction of Bcl-2 in KG1 CD34+CD7- but not in KGla CD34+CD7+ human myeloid leukaemia cells. Meanwhile, RA failed to augment fludarabine-induced reduction of Bcl-2 in both cell types. In conclusion, the present results suggest a potential role for the combination of RA and cytarabine in the treatment of refractory and/or relapsed AML patients with CD34+CD7- but not CD34+CD7+ blast cells.

Administration of Palivizumab in the NICU

BACKGROUND

The American Academy of Pediatrics recommends palivizumab prophylaxis against respiratory syncytial virus (RSV) for infants at high risk for severe disease within 72 hours of hospital discharge to prevent community-associated RSV. The American Academy of Pediatrics does not recommend palivizumab to prevent health care-associated RSV (HA-RSV).

METHODS

A retrospective, multicenter cohort of hospitalized infants who received nondischarge palivizumab (NDP) between January 2009 and December 2013 was established from 14 hospitals. NDP was defined as a charge for palivizumab >7 days before hospital discharge and no previous documented RSV. Infants were considered high risk for severe disease if they had chronic lung disease, chronic heart disease, or prematurity. Nondischarge palivizumab use was examined for high- and low-risk infants. HA-RSV was defined as an RSV-positive test (polymerase chain reaction, enzyme immunoassays, or culture) >3 days after admission and the frequency was measured for infants who did and did not receive NDP.

RESULTS

We identified 1263 patients who received at least 1 dose of NDP, most of whom were classified as high risk (80%). Among high-risk patients, the predictors of receipt of NDP included longer length of stay, institution, and no comorbid conditions. Most of the low-risk patients (88%) who received NDP had no comorbid conditions. NDP use varied widely among institutions. Overall, 25 eligible patients developed HA-RSV; 17 of whom received NDP.

CONCLUSIONS

Despite current recommendations, palivizumab for prevention of HA-RSV was common, even among patients at low risk of severe RSV.

Present or absent on admission: results of changes in National Healthcare Safety Network surveillance definitions

In January 2013, the National Healthcare Safety Network definition of "present on admission" was created. Using existing surveillance data from 2013, we identified health care-associated infections (HAIs) that met prior present on admission criteria but not the new definition. We identified a number of infections classified as HAI despite evidence that infection was clinically present on admission. These findings have important implications for states with mandatory HAI reporting using National Healthcare Safety Network definitions.

Bcl-2 protein in human myeloid leukaemia cells and its down-regulation during chemotherapy-induced apoptosis

Acute myeloid leukaemia (AML) is a heterogeneous malignant disease in which Bcl-2 is expressed simultaneously with several putative drug resistance parameters in AML cells. Bcl-2 over-expression is associated with CD34 positivity, poor response to chemotherapy and reduced overall survival in AML patients. The role of Bcl-2 in determining the response of AML cells to two chemotherapy drugs used in treatment of AML: cytarabine and fludarabine was investigated using human leukaemia cell lines expressing different levels of Bcl-2: U937 CD34 negative expressing low levels of Bcl-2 and MHH225 CD34 positive expressing high levels of Bcl-2. Apoptosis was significantly more in CD34 negative cells with low Bcl-2 expression than in CD34 positive cells with high Bcl-2 expression. The IC50 of cytarabine and fludarabine were significantly higher in CD34 positive cells with high Bcl-2 than in CD34 negative cells with low Bcl-2. Using a quantitative ELISA assay, the results revealed a 2-log higher Bcl-2 concentrations in CD34 positive (144.7 13.3 Units per 105 cells) than in CD34 negative (6.3 0.01 Units per 104 cells) leukaemia cells. Both cytarabine and fludarabine have reduced Bcl-2 concentrations in both cell types. However, the significantly high basal level of Bcl-2 concentrations in CD34 positive leukaemia cells has resulted in a persistent high Bcl-2 concentration levels remaining after treatment with the anti-leukaemia drugs in these cells. Whereas in CD34 negative leukaemia cells the low basal level of Bcl-2 concentrations was significantly reduced by the anti-leukaemia drugs to extremely low levels. Therefore, the high Bcl-2 concentration levels remaining after treatment with anti-leukaemia drugs can be responsible for resistance to chemotherapy by protecting CD34 positive AML cells from induced apoptosis.

Ajoene, a garlic-derived natural compound, enhances chemotherapy-induced apoptosis in human myeloid leukaemia CD34-positive resistant cells

The reputation of garlic as an effective remedy for tumours extends back to the Egyptian Codex Ebers of 1550 BC. Several garlic compounds, including allicin and its corresponding sulfide, inhibit the proliferation of several human malignant cells. Ajoene is a garlic-derived compound produced most efficiently from pure allicin and has the advantage of a greater chemical stability than allicin. Recently, ajoene was shown to inhibit proliferation and induce apoptosis of human leukaemia CD34-negative cells including HL-60, U937, HEL and OCIM-I. More significantly, ajoene was shown to induce 30% apoptosis in myeloblasts from a chronic myeloid leukaemia patient in blastic crisis. Acute myeloid leukaemia (AML) is a heterogeneous malignant disease in which disease progression at the level of CD34-positive cells has a major impact on resistance to chemotherapy and relapse.

MATERIALS AND METHODS

The aim of the present study was to investigate the effect of ajoene on changes in the expression of apoptosis-related proteins: bcl-2 and caspase-3, induced by two principal drugs used in treatment of AML, cytarabine and fludarabine, in KGI human myeloid leukaemia CD34-positive-resistant cells. Both quantitative ELISA measurement of bcl-2 and colourimetric measurement of active caspase-3 were used.

RESULTS

Quantitative ELISA measurement of bcl-2 (units per million cells) showed treatment of KG1-resistant leukaemia cells with 40 microM ajoene alone to significantly reduce the bcl-2-expression from 239.5 +/- 1.5 in control cultures to only 22.0 +/- 4.0 in ajoene-treated cultures. Fludarabine had significantly more inhibitory effect on bcl-2-expression than cytarabine in KGI-resistant myeloid leukaemia cells. Ajoene significantly enhanced the inhibitory effect of the two chemotherapeutic drugs, cytarabine and fludarabine, on bcl-2-expression in KGI cells. Bcl-2-expression could not be detected in fludarabine + ajoene-treated cultures. The Western blot of bcl-2-expression in KGI control and treated cells confirmed the quantitative ELISA measurements. Quantitative measurement of activated caspase-3 (pg per million cells) showed the two drugs, cytarabine and fludarabine, significantly increased the activated caspase-3 level in KGI myeloid leukaemia cells.

CONCLUSION

The addition of ajoene enhanced the activation of caspase-3 in both cytarabine- and fludarabine-treated KGI cells. In conclusion, the present results suggest a potential role for the combination of ajoene with fludarabine-based chemotherapy in the treatment of refractory and/or relapsed AML patients. Further studies are warranted to evaluate a similar enhancing effect for ajoene in blast cells from AML patients in primary cultures.