Safety, efficacy, and pharmacokinetics of gremubamab (MEDI3902), an anti-Pseudomonas aeruginosa bispecific human monoclonal antibody, in P. aeruginosa-colonised, mechanically ventilated intensive care unit patients: a randomised controlled trial

BACKGROUND

Ventilator-associated pneumonia caused by Pseudomonas aeruginosa (PA) in hospitalised patients is associated with high mortality. The effectiveness of the bivalent, bispecific mAb MEDI3902 (gremubamab) in preventing PA nosocomial pneumonia was assessed in PA-colonised mechanically ventilated subjects.

METHODS

EVADE (NCT02696902) was a phase 2, randomised, parallel-group, double-blind, placebo-controlled study in Europe, Turkey, Israel, and the USA. Subjects ≥ 18 years old, mechanically ventilated, tracheally colonised with PA, and without new-onset pneumonia, were randomised (1:1:1) to MEDI3902 500, 1500 mg (single intravenous dose), or placebo. The primary efficacy endpoint was the incidence of nosocomial PA pneumonia through 21 days post-dose in MEDI3902 1500 mg versus placebo, determined by an independent adjudication committee.

RESULTS

Even if the initial sample size was not reached because of low recruitment, 188 subjects were randomised (MEDI3902 500/1500 mg: n = 16/87; placebo: n = 85) between 13 April 2016 and 17 October 2019. Out of these, 184 were dosed (MEDI3902 500/1500 mg: n = 16/85; placebo: n = 83), comprising the modified intent-to-treat set. Enrolment in the 500 mg arm was discontinued due to pharmacokinetic data demonstrating low MEDI3902 serum concentrations. Subsequently, enrolled subjects were randomised (1:1) to MEDI3902 1500 mg or placebo. PA pneumonia was confirmed in 22.4% (n = 19/85) of MEDI3902 1500 mg recipients and in 18.1% (n = 15/83) of placebo recipients (relative risk reduction [RRR]: - 23.7%; 80% confidence interval [CI] - 83.8%, 16.8%; p = 0.49). At 21 days post-1500 mg dose, the mean (standard deviation) serum MEDI3902 concentration was 9.46 (7.91) μg/mL, with 80.6% (n = 58/72) subjects achieving concentrations > 1.7 μg/mL, a level associated with improved outcome in animal models. Treatment-emergent adverse event incidence was similar between groups.

CONCLUSIONS

The bivalent, bispecific monoclonal antibody MEDI3902 (gremubamab) did not reduce PA nosocomial pneumonia incidence in PA-colonised mechanically ventilated subjects. Trial registration Registered on Clinicaltrials.gov ( NCT02696902 ) on 11th February 2016 and on EudraCT ( 2015-001706-34 ) on 7th March 2016.

Efficacy and safety of suvratoxumab for prevention of Staphylococcus aureus ventilator-associated pneumonia (SAATELLITE): a multicentre, randomised, double-blind, placebo-controlled, parallel-group, phase 2 pilot trial

BACKGROUND

Staphylococcus aureus remains a common cause of ventilator-associated pneumonia, with little change in incidence over the past 15 years. We aimed to evaluate the efficacy of suvratoxumab, a monoclonal antibody targeting the α toxin, in reducing the incidence of S aureus pneumonia in patients in the intensive care unit (ICU) who are on mechanical ventilation.

METHODS

We did a multicentre, randomised, double-blind, placebo-controlled, parallel-group, phase 2 pilot trial at 31 hospitals in Belgium, the Czech Republic, France, Germany, Greece, Hungary, Portugal, Spain, and Switzerland. Eligible patients were in the ICU, aged ≥18 years, were intubated and on mechanical ventilation, were positive for S aureus colonisation of the lower respiratory tract, as assessed by quantitative PCR (qPCR) analysis of endotracheal aspirate, and had not been diagnosed with new-onset pneumonia. Patients were excluded if they had confirmed or suspected acute ongoing staphylococcal disease; had received antibiotics for S aureus infection for more than 48 h within 72 h of randomisation; had a Clinical Pulmonary Infection Score of 6 or higher; had an acute physiology and chronic health evaluation II score of 25 or higher with a Glasgow coma scale (GCS) score of more than 5, or an acute physiology and chronic health evaluation II score of at least 30 with a GCS score of 5 or less; had a Sequential Organ Failure Assessment score of 9 or higher; or had active pulmonary disease that would impair the ability to diagnose pneumonia. Colonised patients were randomly assigned (1:1:1), by use of an interactive voice or web response system, to receive either a single intravenous infusion of suvratoxumab 2000 mg, suvratoxumab 5000 mg, or placebo. Randomisation was done in blocks of size four, stratified by country and by whether patients had received systemic antibiotics for S aureus infection. Patients, investigators, and study staff involved in the treatment or clinical evaluation of patients were masked to patient assignment. The primary efficacy endpoint was the incidence of S aureus pneumonia at 30 days, as determined by a masked independent endpoint adjudication committee, in all patients who received their assigned treatment (modified intention-to-treat [ITT] population). Primary safety endpoints were the incidence of treatment-emergent adverse events at 30 days, 90 days, and 190 days after treatment, and the incidence of treatment-emergent serious adverse events, adverse events of special interest, and new-onset chronic disease at 190 days after treatment. All primary safety endpoints were assessed in the modified ITT population. This trial is registered with ClinicalTrials.gov (NCT02296320) and the EudraCT database (2014-001097-34).

FINDINGS

Between Oct 10, 2014, and April 1, 2018, 767 patients were screened, of whom 213 patients with confirmed S aureus colonisation of the lower respiratory tract were randomly assigned to the suvratoxumab 2000 mg group (n=15), the suvratoxumab 5000 mg group (n=96), or the placebo group (n=102). Two patients in the placebo group did not receive treatment after randomisation because their clinical conditions changed and they no longer met the eligibility criteria for dosing. As adjudicated by the data monitoring committee at an interim analysis, the suvratoxumab 2000 mg group was discontinued on the basis of predefined pharmacokinetic criteria. At 30 days after treatment, 17 (18%) of 96 patients in the suvratoxumab 5000 mg group and 26 (26%) of 100 patients in the placebo group had developed S aureus pneumonia (relative risk reduction 31·9% [90% CI -7·5 to 56·8], p=0·17). The incidence of treatment-emergent adverse events at 30 days were similar between the suvratoxumab 5000 mg group (87 [91%]) and the placebo group (90 [90%]). The incidence of treatment-emergent serious adverse events at 30 days were also similar between the suvratoxumab 5000 mg group (36 [38%]) and the placebo group (32 [32%]). No significant difference in the incidence of treatment-emergent adverse events between the two groups at 90 days (89 [93%] in the suvratoxumab 5000 mg group vs 92 [92%] in the placebo group) and at 190 days (93 [94%] vs 93 [93%]) was observed. 40 (40%) patients in the placebo group and 50 (52%) in the suvratoxumab 5000 mg group had a serious adverse event at 190 days. In the suvratoxumab 5000 mg group, one (1%) patient reported at least one treatment-emergent serious adverse event related to treatment, two (2%) patients reported an adverse event of special interest, and two (2%) reported a new-onset chronic disease.

INTERPRETATION

In patients in the ICU receiving mechanical ventilation with qPCR-confirmed S aureus colonisation of the lower respiratory tract, the incidence of S aureus pneumonia at 30 days was not significantly lower following treatment with 5000 mg suvratoxumab than with placebo. Despite these negative results, monoclonal antibodies still represent one promising therapeutic option to reduce antibiotic consumption that require further exploration and studies.

FUNDING

AstraZeneca, with support from the Innovative Medicines Initiative Joint Undertaking.

1486. Phylogenetic and alpha toxin variant analyses of Staphylococcus aureus strains isolated from patients during the SAATELLITE study

Background

Suvratoxumab is a human monoclonal antibody that neutralizes S. aureus (SA) alpha toxin (AT). SAATELLITE, a phase 2 study of the safety and efficacy of suvratoxumab for reducing the incidence of SA pneumonia (NCT02296320), was conducted within the consortium for Combatting Bacterial Resistance in Europe.

Methods

A total of 304 SA isolates (baseline, onset and last available isolates from suspected serious bacterial infections, SSBIs) collected from the lower respiratory tract samples from 165 subjects during SAATELLITE were subjected to whole genome sequencing.

AT gene (hla) sequences were translated and amino acid variation was identified in comparison to the reference SA USA300 FPR3757. Phylogenetic analysis, genomic annotation and ST analysis were performed.

AT expression in SA culture supernatants was performed by ELISA. Representative isolates with novel AT subtypes that had not been identified in previous studies were tested for hemolytic activity and suvratoxumab neutralizing activity.

Wilcoxon rank sum test and Fisher’s exact test were performed, respectively: a) to compare difference in baseline AT expression in relation to SA pneumonia incidence; b) to evaluate the association between occurrence of AT stop codons and incidence of SA pneumonia at baseline, as well as the association between occurrence of AT stop codons and treatment arms at post baseline.

Results

We identified a total of 44 sequence types (STs) and 21 unique AT subtypes, 7 of which have not been described previously. No substitutions were located in the suvratoxumab binding region and all novel AT subtypes displaying lytic activity were neutralized by suvratoxumab.

We detected stop codons Q113B and W205B in AT sequences in 53 and 2 SA isolates, respectively. We uncovered no significant associations of: 1) baseline AT expression with SA pneumonia incidence [p=0.967]; 2) occurrence of AT gene stop codon with either SA pneumonia incidence [p >0.999] or suvratoxumab treatment [p=0.103; lower frequency of stop codons in suvratoxumab arm versus placebo].

Conclusion

Our data indicated that: 1) suvratoxumab target region in (AT) remains conserved; 2) suvratoxumab is active against all AT variants identified to date; 3) suvratoxumab did not exert pressure on SA clinical isolates for selection of escape mutants.

Disclosures

David E. Tabor, PhD, AstraZeneca (Employee, Shareholder) Andrey Tovchigrechko, PhD, AstraZeneca (Employee, Shareholder)KitePharma, a Gilead company (Employee, Shareholder) Bret R. Sellman, PhD, AstraZeneca (Employee, Shareholder) Michael McCarthy, n/a, AstraZeneca (Employee) Kathryn Shoemaker, MS, AstraZeneca (Employee) Hasan S. Jafri, MD, FAAP, AstraZeneca (Employee) Mark T. Esser, PhD, AstraZeneca (Employee) Alexey Ruzin, PhD, AstraZeneca (Employee, Shareholder)

635. Efficacy, Pharmacokinetics (PK), and Safety Profile of MEDI3902, an Anti-Pseudomonas aeruginosa Bispecific Human Monoclonal Antibody in Mechanically Ventilated Intensive Care Unit Patients; Results of the Phase 2 EVADE Study Conducted by the Public-Private COMBACTE-MAGNET Consortium in the Innovative Medicines Initiative (IMI) Program

Background

Pseudomonas aeruginosa (PA) pneumonia is associated with morbidity and mortality in mechanically ventilated, intensive care unit (MV ICU) patients despite best clinical care. We assessed efficacy, PK, and safety of MEDI3902 in MV ICU subjects in the placebo-controlled, randomized Phase 2 EVADE study (NCT02696902; EudraCT 2015-001706-34).

Methods

Subjects with PCR-confirmed PA colonization of the lower respiratory tract were randomized to either a single IV infusion of 1,500 mg MEDI3902 (n = 85) or placebo (n = 83). Primary Efficacy endpoint was Endpoint Adjudication Committee-determined relative risk reduction (RRR) of PA pneumonia incidence in MEDI3902 vs. placebo recipients within 21 days post dose (2-sided α = 0.2). Serum MEDI3902 PK levels were measured through 49 days post dose. Treatment-emergent adverse events (TEAEs) and serious AEs (SAEs) were assessed through 49 days post dose.

Results

Baseline characteristics were similar between groups. MEDI3902 did not meet the primary endpoint of PA pneumonia vs. placebo (22.4% vs. 18.1%; RRR -23.7%, P = 0.491). Mean serum MEDI3902 level was 9.46 µg/mL (target 1.7µg/mL) at 21 days post dose, with a t½ 5.6 days. Proportion of subjects with TEAEs was similar between groups: ≥1 TEAE (98.8% MEDI3902; 97.6% placebo); ≥1 serious; and/or ≥grade 3 severity SAE (70.6% MEDI3902; 66.3% placebo). Deaths were numerically higher, although not statistically significant (24 (28.2%) MEDI3902 vs 19 (22.9%) Placebo; RRR -23.3%, P 0.429). Post-hoc analyses suggested RRR 47% among ~70% of the study population who had baseline Procalcitonin levels < 0.55 µg/L (12.5% MEDI3902 vs 23.7% placebo; 80%CI 6.1%-69.9%; P 0.135). Similarly, RRR 83% was observed among 50% of study subjects with baseline absolute neutrophil count (ANC) of < 8170 /µL (2.8% MEDI3902 vs 17.0% placebo; 80%CI 39.5%-95.5%; P 0.038). Subjects with Procalcitonin < 0.55 µg/L and ANC < 8170/ µL also had higher serum PK exposure.

Conclusion

A single IV dose of MEDI3902 provided PK exposure above the target level but did not achieve primary efficacy endpoint of reduction in PA pneumonia. Efficacy trends were observed in subjects with lower levels of baseline inflammatory biomarkers. MEDI3902 may have a path forward in certain patient populations such as ICU patients with lower baseline inflammation.

Disclosures

Jean Chastre, MD, AstraZeneca (Scientific Research Study Investigator) Marc Bourgeois, MD, AstraZeneca (Scientific Research Study Investigator) Apostolos Komnos, MD, PhD, AstraZeneca (Scientific Research Study Investigator) Ricard Ferrer, MD, PhD, Shionogi B.V. (Advisor or Review Panel member) Galia Rahav, MD, AstraZeneca (Scientific Research Study Investigator) Nicolas De Schryver, MD, AstraZeneca (Scientific Research Study Investigator) Alain Lepape, MD, AstraZeneca (Scientific Research Study Investigator) Miguel Sanchez Garcia, MD, PhD, AstraZeneca (Scientific Research Study Investigator) Antoni Torres, MD, PhD, AstraZeneca (Scientific Research Study Investigator) Omar Ali, PhD, AstraZeneca (Employee) Kathryn Shoemaker, MS, AstraZeneca (Employee) Alexey Ruzin, PhD, AstraZeneca (Employee, Shareholder) Yu Jiang, PhD, AstraZeneca (Employee) Susan Colbert, BSN, AstraZeneca (Employee) Drieke Vandamme, PhD, AstraZeneca (Scientific Research Study Investigator) Terramika Bellamy, n/a, AstraZeneca (Employee) Colin Reisner, MD, AstraZeneca (Employee) Filip Dubovsky, MD, MPH, AstraZeneca (Employee) Hasan S. Jafri, MD, FAAP, AstraZeneca (Employee)

Association of Staphylococcus aureus Colonization and Pneumonia in the Intensive Care Unit

IMPORTANCE

Carriage of Staphylococcus aureus is associated with S aureus infection. However, associations between S aureus carriage and the development of S aureus intensive care unit (ICU) pneumonia (SAIP) have not been quantified accurately, and interpretation of available data is hampered because of variations in definitions.

OBJECTIVE

To quantify associations of patient-related and contextual factors, including S aureus colonization status, with the occurrence of SAIP.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted in ICUs of 30 hospitals in 11 European countries, geographically spread across 4 regions. Among patients with an anticipated length of stay 48 hours or longer who were undergoing mechanical ventilation at ICU admission, S aureus colonization was ascertained in the nose and lower respiratory tract. From this group, S aureus-colonized and noncolonized patients were enrolled into the study cohort in a 1:1 ratio. Data analysis was performed from May to November 2019.

MAIN OUTCOMES AND MEASURES

SAIP was defined as any pneumonia during the ICU stay developing 48 hours or more after ICU admission with S aureus isolated from lower respiratory tract specimens or blood samples. The incidence of SAIP was derived in the study cohort and estimated on the weighted incidence calculation for the originating overarching population, while taking competing events into account. Weighted risk factor analysis was performed using Cox multivariable regression.

RESULTS

The study cohort consisted of 1933 patients (mean [SD] age, 62.0 [16.0] years); 1252 patients (64.8%) were men, and 950 patients (49.1%) were S aureus carriers at ICU admission. In all, 304 patients (15.7%) developed ICU-acquired pneumonia, of whom 131 patients (6.8%) had SAIP. Weighted SAIP incidences were 11.7 events per 1000 patient-days in the ICU for S aureus-colonized patients and 2.9 events per 1000 patient-days in the ICU for noncolonized patients (overall incidence, 4.9 events per 1000 patient-days in the ICU). The only factor independently associated with SAIP was S aureus colonization status at ICU admission (cause-specific hazard ratio, 3.6; 95% CI, 2.2-6.0; P < .001). There were marked regional differences in SAIP incidence and cause-specific hazard ratios for colonization status.

CONCLUSIONS AND RELEVANCE

SAIP incidence was 4.9 events per 1000 ICU patient-days for patients undergoing mechanical ventilation at ICU admission (or shortly thereafter). The daily risk of SAIP was 3.6 times higher in patients colonized with S aureus at ICU admission compared with noncolonized patients.

2160. Performance of the Cepheid Rapid PCR Test for Patient Screening and Association with Efficacy of Suvratoxumab, A Novel Anti-Staphylococcus aureus Monoclonal Antibody, During the Phase 2 SAATELLITE study

Background

Patients with lower airway Staphylococcus aureus (SA) colonization are at great risk (> 20%) of early-onset ventilator-associated pneumonia (VAP). Thus, a rapid test is required to identify patients at risk. Suvratoxumab (formerly MEDI4893) is a human monoclonal antibody that neutralizes SA alpha toxin. SAATELLITE, a phase 2 study of safety and efficacy of suvratoxumab for reducing the incidence of SA pneumonia (NCT02296320) was conducted and recently completed within the consortium for Combatting Bacterial Resistance in Europe. We investigated the performance of a rapid PCR test (Xpert MRSA/SA SSTI™, Cepheid) as a screening tool during the study and the association between SA load and suvratoxumab efficacy.

Methods

The PCR assay was used to detect SA and methicillin-resistant SA (MRSA) in lower respiratory tract (LRT) samples. Culture was performed on PCR SA+ LRT samples according to local procedures. PCR SA+ subjects were randomized 1:1 to either a single intravenous infusion of 5000 mg suvratoxumab (n = 96) or placebo (n = 100) and followed for 190 days post dose. Efficacy of suvratoxumab was defined as relative risk reduction (RRR) in incidence of SA pneumonia within 30 days post-dose compared with placebo.

Results

299 (41.5%) out of 720 screened subjects were SA+ by PCR. Of 209 subjects with culture data, there were 162 (77.5%) SA+, 47 (22.5%) SA- and 9 (5.6%) MRSA by culture. Culture results could have been affected by antibiotic use and site variability in limits of detection ranging from 3.3 to 100,000 colony-forming units per mL (CFU/mL). No discordance was noted between PCR and culture for MRSA detection. An inverse linear correlation was observed between the PCR cycle threshold (Ct) values for SA protein A gene (spa) and SA CFU/mL counts from quantitative culture. In subjects with low SA load (Ct ≥ 29; n = 72), suvratoxumab provided 66.7% RRR [90% confidence interval (CI): 21.3%, 86.2%] compared with 31.9% RRR [90% CI: -7.5%, 56.8%] in total study population.

Conclusion

Cepheid Xpert PCR assay was easy to perform, sensitive and standardized, and provided better sensitivity than conventional culture for detection of SA. Additionally, quantitative PCR Ct output was associated with the efficacy of suvratoxumab in reducing SA pneumonia incidence.

Disclosures

All authors: No reported disclosures.

2839. Efficacy, Pharmacokinetics (PK), and Safety Profile of Suvratoxumab (MEDI4893), a Staphylococcus aureus Alpha Toxin (AT)-Neutralizing Human Monoclonal Antibody in Mechanically Ventilated Patients in Intensive Care Units; Results of the Phase 2 SAATELLITE Study Conducted by the Public-Private COMBACTE Consortium

Background

Staphylococcus aureus (SA) pneumonia imposes significant morbidity and mortality in mechanically ventilated, intensive care unit (MV ICU) patients despite best clinical care. We assessed efficacy, PK, AT-neutralizing antibodies (AT NAbs), and safety of suvratoxumab (suvra) in MV ICU subjects in the placebo-controlled, randomized Phase 2 SAATELLITE study (NCT02296320; EudraCT 2014-001097-34).

Methods

Subjects with PCR-confirmed SA colonization of the lower respiratory tract were randomized to either a single intravenous infusion of 5,000 mg suvra (n = 96) or placebo (n = 100) and followed for 190 days post dose. Efficacy endpoints were Endpoint Adjudication Committee-determined relative risk reduction (RRR) of SA pneumonia incidence in suvra vs. placebo recipients within 30 days post dose (primary endpoint, tested at 2-sided α = 0.1), incidence of all-cause pneumonia, and all-cause pneumonia or death. Serum suvra PK and levels of AT NAbs were measured through 90 days post dose and analyzed for statistical correlation. Treatment-emergent adverse events (TEAEs) and serious AEs (SAEs) were assessed through 190 days post dose.

Results

Baseline characteristics were similar between groups. Suvra provided 31.9% RRR in incidence of SA pneumonia vs. placebo (17.7% vs. 26%; P = 0.166), 30% RRR (P = 0.146) in incidence of all-cause pneumonia, and 23% RRR (P = 0.164) in incidence of all-cause pneumonia or death. Suvra reduced mean hospital stay and ICU duration by 3.0 and 2.4 days, resp. vs. placebo. Mean serum ± SD suvra level was 296 ± 131 µg/mL at 30 days post dose. Serum AT Nab ± SD levels reached 156.03 ± 72.48 IU/mL at 2 days post dose, declining slowly to 33.74 ± 16.04 IU/mL by 90 days post dose. AT NAbs correlated with PK (r2 = 0.7), thereby confirming functional activity of suvra over time. Proportion of subjects with TEAEs or SAEs was similar between groups: ≥1 TEAE (93.8% suvra; 93.0% placebo); ≥1 serious; and/or ≥grade 3 severity SAE (66.7% suvra; 58.0% placebo).

Conclusion

A single intravenous dose of suvra produced a trend toward reduced incidence of SA pneumonia, health resource savings, sustained functional exposure in serum, and an acceptable safety profile. These results support continued development of suvra in MV ICU patients.

Disclosures

All Authors: No reported Disclosures.

1557. Population Pharmacokinetics of Suvratoxumab (MEDI4893), an Extended Half-life Staphylococcus aureus Alpha Toxin-Neutralizing Human Monoclonal Antibody, in Healthy Adults and Patients on Mechanical Ventilation in Intensive Care Units

Background

Suvratoxumab (suvra), an extended half-life (~80 days), Staphylococcus aureus (SA) alpha toxin-neutralizing IgG monoclonal antibody, is under investigation for prevention of SA pneumonia in patients on mechanical ventilation (MV). We characterized the serum PK of suvra using population pharmacokinetics (popPK) in both healthy volunteers and MV patients and quantified the proportion of patients reaching the serum target of 211 μg/mL at 30 days post-dose.

Methods

The popPK analysis included 1,368 serum samples from two early phase studies (NCT02296320; EudraCT 2014-001097-34): (1) Phase 1 study in 26 healthy adults receiving single IV suvra doses ranging from 0.225g to 5g, with PK sampled up to 360 days; and (2) Phase 2 study in MV patients with PCR-confirmed SA colonization of lower respiratory tract receiving one suvra IV dose of 2g (n = 15) or 5g (n = 96), with PK sampled up to 100 days.

Results

A two-compartment linear model with weight-based scaling of the PK parameters adequately described the serum PK data (Figure 1). MV status, number of days on MV, and age impacted the PK of suvra. A moderate between-subject variability (<45% CV) was estimated for key PK parameters. An estimated two-fold increase in MV patients’ volume of distribution parameters compared with healthy volunteers explained the observed C_max differences between the two groups (1145±369 μg/mL vs. 1783±396 μg/mL) (Figures 2 and 3). Although age, MV status and days on MV post-dose appeared to be associated with higher systemic clearance (CL) in the model, this estimate could be biased due to limited PK data available for only one half-life (~90 days) of the drug in MV patients (Figure 2). More patients achieved suvra levels above the PK target following the 5 g (73.5%; 50/68) vs. 2 g dose (7.6%; 1/13) at 30 days post-dose.

Conclusion

MV status, post-dose duration on MV, body weight, and age were identified as statistically significant covariates influencing the PK of suvra. Serum PK and popPK analyses support the 5g dose for future studies with suvra in MV patients.

Disclosures

All authors: No reported disclosures.

Risk prediction for Staphylococcus aureus surgical site infection following cardiothoracic surgery; A secondary analysis of the V710-P003 trial

Background

Identifying patients undergoing cardiothoracic surgery at high risk of Staphylococcus aureus surgical site infection (SSI) is a prerequisite for implementing effective preventive interventions. The objective of this study was to develop a risk prediction model for S. aureus SSI or bacteremia after cardiothoracic surgery based on pre-operative variables.

Materials/Methods

Data from the Merck Phase IIb/III S. aureus vaccine (V710-P003) clinical trial were analyzed. In this randomized placebo-controlled trial, the effect of preoperative vaccination against S. aureus was investigated in patients undergoing cardiothoracic surgery. The primary outcome was deep/superficial S. aureus SSI or S. aureus bacteremia through day 90 after surgery. Performance, calibration, and discrimination of the final model were assessed.

Results

Overall 164 out of 7,647 included patients (2.1%) developed S. aureus infection (149 SSI, 15 bacteremia, 28 both). Independent risk factors for developing the primary outcome were pre-operative colonization with S. aureus (OR 3.08, 95% confidence interval [CI] 2.23–4.22), diabetes mellitus (OR 1.87, 95% CI 1.34–2.60), BMI (OR 1.02 per kg/m², 95% CI 0.99–1.05), and CABG (OR 2.67, 95% CI 1.91–3.78). Although vaccination had a significant (albeit modest) protective effect, it was omitted from the model because its addition did not significantly change the coefficients of the final model and V710-vaccine development has been discontinued due to insufficient efficacy. The final prediction model had moderate discriminative accuracy (AUC-value, 0.72).

Conclusion

Pre-operative S. aureus colonization status, diabetes mellitus, BMI, and type of surgical procedure moderately predicted the risk of S. aureus SSI and/or bacteremia among patients undergoing cardiothoracic surgery.

Characterisation of anti-alpha toxin antibody levels and colonisation status after administration of an investigational human monoclonal antibody, MEDI4893, against Staphylococcus aureus alpha toxin

Objectives

MEDI4893 is a novel, long‐acting human monoclonal antibody targeting Staphylococcus aureus (SA) alpha toxin (AT). This report presents the results of the exploratory analyses from a randomised phase 1 dose‐escalation study in healthy human subjects receiving single intravenous MEDI4893 doses or placebo.

Methods

Anti‐AT antibodies and AT expression were measured as described previously. Nasal swabs were analysed by culture and PCR. Data were summarised by treatment groups and visits by using SAS System Version 9.3.

Results

Subjects receiving 2250 or 5000 mg of MEDI4893 had the highest serum anti‐AT neutralising antibody (NAb) levels: approximately 180‐ to 240‐, 70‐ to 100‐ and sevenfold to 10‐fold higher than respective baseline levels at peak, 30 and 360 days, respectively. In these subjects, levels of serum anti‐AT NAbs were >3.2 International Units (IU) mL⁻¹ for at least 211 days. In the upper respiratory tract, anti‐AT NAb levels increased with MEDI4893 dose. No apparent effect of MEDI4893 on SA nasal colonisation, hla gene sequence or AT expression was observed. Five AT variants were detected, their lytic activity was fully neutralised by MEDI4893.

Discussion

Our results indicate that (1) MEDI4893 administration at 2250 and 5000 mg would provide effective immunoprophylaxis against systemic SA disease; (2) MEDI4983 distributes to the upper respiratory tract and retains neutralising activity against AT; and (3) potential for emergence of MEDI4893 resistance is low.

Conclusion

Intravenous administration of MEDI4893 maintained levels of anti‐AT NAbs in serum and nasal mucosa that may provide effective immunoprophylaxis against SA disease and support continued clinical development of MEDI4893.

Respiratory Syncytial Virus Genotypes, Host Immune Profiles, and Disease Severity in Young Children Hospitalized With Bronchiolitis

Background

Data on how respiratory syncytial virus (RSV) genotypes influence disease severity and host immune responses is limited. Here, we characterized the genetic variability of RSV during 5 seasons, and evaluated the role of RSV subtypes, genotypes, and viral loads in disease severity and host transcriptional profiles.

Methods

A prospective, observational study was carried out, including a convenience sample of healthy infants hospitalized with RSV bronchiolitis. Nasopharyngeal samples for viral load quantitation, typing, and genotyping, and blood samples for transcriptome analyses were obtained within 24 hours of hospitalization. Multivariate models were constructed to identify virologic and clinical variables predictive of clinical outcomes.

Results

We enrolled 253 infants (median age 2.1 [25%-75% interquartile range] months). RSV A infections predominated over RSV B and showed greater genotype variability. RSV A/GA2, A/GA5, and RSV B/BA were the most common genotypes identified. Compared to GA2 or BA, infants with GA5 infections had higher viral loads. GA5 infections were associated with longer hospital stay, and with less activation of interferon and increased overexpression of neutrophil genes.

Conclusions

RSV A infections were more frequent than RSV B, and displayed greater variability. GA5 infections were associated with enhanced disease severity and distinct host immune responses.

Perceived barriers to pediatrician and family practitioner participation in pediatric clinical trials: Findings from the Clinical Trials Transformation Initiative

Despite legislation to stimulate pediatric drug development through clinical trials, enrolling children in trials continues to be challenging. Non-investigator (those who have never served as a clinical trial investigator) providers are essential to recruitment of pediatric patients, but little is known regarding the specific barriers that limit pediatric providers from participating in and referring their patients to clinical trials. We conducted an online survey of pediatric providers from a wide variety of practice types across the United States to evaluate their attitudes and awareness of pediatric clinical trials. Using a 4-point Likert scale, providers described their perception of potential barriers to their practice serving as a site for pediatric clinical trials. Of the 136 providers surveyed, 52/136 (38%) had previously referred a pediatric patient to a trial, and only 17/136 (12%) had ever been an investigator for a pediatric trial. Lack of awareness of existing pediatric trials was a major barrier to patient referral by providers, in addition to consideration of trial risks, distance to the site, and time needed to discuss trial participation with parents. Overall, providers perceived greater challenges related to parental concerns and parent or child logistical barriers than study implementation and ethics or regulatory barriers as barriers to their practice serving as a trial site. Providers who had previously been an investigator for a pediatric trial were less likely to be concerned with potential barriers than non-investigators. Understanding the barriers that limit pediatric providers from collaboration or inhibit their participation is key to designing effective interventions to optimize pediatric trial participation.

New Strategies Targeting Virulence Factors of Staphylococcus aureus and Pseudomonas aeruginosa

Morbidity, mortality, and economic burden of nosocomial pneumonia caused by Staphylococcus aureus and Pseudomonas aeruginosa remain high in mechanically ventilated and hospitalized patients despite the use of empirical antibiotic therapy or antibiotics against specific classes of pathogens and procedures to reduce nosocomial infections in hospital settings. Newer agents that neutralize or inhibit specific S. aureus or P. aeruginosa virulence factors may eliminate or reduce the risk for developing pneumonia before or during mechanical ventilation and may improve patient outcomes through mechanisms that differ from those of antibiotics. In this article, we review the types, mechanisms of action, potential advantages, and stage of development of antivirulence agents (AVAs) that hold promise as alternative preventive or interventional therapies against S. aureus– and P. aeruginosa–associated nosocomial pneumonias. We also present and discuss challenges to the effective utilization of AVAs separately from or in addition to antibiotics and the design of clinical trials and meaningful study end points.

The Innovative Medicines Initiative's New Drugs for Bad Bugs programme: European public-private partnerships for the development of new strategies to tackle antibiotic resistance

Antibiotic resistance (ABR) is a global public health threat. Despite the emergence of highly resistant organisms and the huge medical need for new drugs, the development of antibacterials has slowed to an unacceptable level worldwide. Numerous government and non-government agencies have called for public-private partnerships and innovative funding mechanisms to address this problem. To respond to this public health crisis, the Innovative Medicines Initiative Joint Undertaking programme has invested more than €660 million, with a goal of matched contributions from the European Commission and the European Federation of Pharmaceutical Industries and Associations, in the development of new antibacterial strategies. The New Drugs for Bad Bugs (ND4BB) programme, an Innovative Medicines Initiative, has the ultimate goal to boost the fight against ABR at every level from basic science and drug discovery, through clinical development to new business models and responsible use of antibiotics. Seven projects have been launched within the ND4BB programme to achieve this goal. Four of them will include clinical trials of new anti-infective compounds, as well as epidemiological studies on an unprecedented scale, which will increase our knowledge of ABR and specific pathogens, and improve the designs of the clinical trials with new investigational drugs. The need for rapid concerted action has driven the funding of seven topics, each of which should add significantly to progress in the fight against ABR. ND4BB unites expertise and provides a platform where the commitment and resources required by all parties are streamlined into a joint public-private partnership initiative of unprecedented scale.

Efficacy of motavizumab for the prevention of respiratory syncytial virus disease in healthy Native American infants: a phase 3 randomised double-blind placebo-controlled trial

BACKGROUND

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infections in children. We aimed to assess the safety and efficacy of an anti-RSV monoclonal antibody (motavizumab) in healthy term (≥36 weeks' gestational age) infants for the prevention of medically attended RSV acute lower respiratory tract infections.

METHODS

This phase 3, double-blind, placebo-controlled, randomised trial enrolled healthy Native American infants aged 6 months or younger who were born at 36 weeks' gestational age in southwestern USA, on the Navajo Nation, the White Mountain Apache reservation, and the San Carlos Apache Indian reservation. Participants were randomly assigned (2:1) to receive either five monthly intramuscular doses of motavizumab (15 mg/kg) or placebo. They were followed up for 150 days after the first dose, and the primary endpoints were respiratory admission to hospital with a positive result for RSV by RT-PCR and death caused by RSV. Participants were followed up for medically attended wheezing until they reached age 3 years. Analysis was by intention to treat (ITT). This trial is registered with ClinicalTrials.gov, number NCT00121108.

FINDINGS

During the autumn seasons (October to December) between 2004 and 2007, 2127 infants of the 2596 infants enrolled were randomly assigned to receive either motavizumab (1417) or placebo (710). After ITT analysis, motavizumab resulted in an 87% relative reduction (relative risk [RR] 0·13, 95% CI 0·08-0·21) in the proportion of infants admitted to hospital with RSV (21 [2%] of 1417 participants who received motavizumab; 80 [11%] of 710 participants who received placebo, p<0·0001). Serious adverse events were less common in particpants taking motavizumab (212 [15%]) than particpants on placebo (148 [21%]). Six deaths occurred in study participants (motavizumab, n=4 [0·3%]; placebo, n=2 [0·3%]); none were deemed to be related to the study product. Hypersensitivity events were more common in patients given motavizumab (208 [14·7%]) than in placebo recipients (87 [12·3%]; p=0·14). There was no effect on rates of medically attended wheezing in children aged 1-3 years (190 [14·9%] of participants randomly assigned to receive motavizumab vs 90 [14·0%] participants randomly assigned to receive placebo).

INTERPRETATION

To our knowledge, this is the only trial of an anti-RSV antibody to prevent serious RSV disease in healthy term infants. Motavizumab significantly reduced the RSV-associated inpatient and outpatient burden and set a benchmark for the efficacy of RSV prevention strategies. The findings do not support a direct, generalisable, causal association between RSV lower respiratory tract infection and subsequent long-term wheezing in term infants.

FUNDING

MedImmune.

Randomized, Double-Blind Study of the Safety of the Liquid Versus Lyophilized Formulation of Palivizumab in Premature Infants and Children with Chronic Lung Disease of Prematurity

Introduction

To avoid the need for reconstitution required by lyophilized palivizumab, a liquid formulation was developed. This study assessed the safety and antidrug antibodies (ADA) of the liquid formulation of palivizumab compared with the lyophilized formulation.

Methods

This phase 4, randomized, double-blind, multicenter study included children with chronic lung disease of prematurity who were ≤24 months of age and children born prematurely with a gestational age of ≤35 weeks who were ≤6 months of age at randomization. Subjects were randomized 1:1 to 15 mg/kg of either liquid or lyophilized palivizumab administered via intramuscular injection every 30 days for a total of 5 injections. Safety was assessed based on serious adverse events (SAEs). ADA to palivizumab was assessed using blood collected at baseline and at a time point between study days 240 and 300.

Results

A total of 413 subjects were included in the analyses. The incidence of SAEs reported was 8.5% with liquid palivizumab and 5.9% with lyophilized palivizumab; none were deemed drug-related. The reported SAEs were consistent with expected conditions in this pediatric age group; there was no increase in respiratory syncytial virus (RSV) disease with liquid palivizumab. At study days 240–300, antipalivizumab antibodies were detected in none of the subjects in the liquid palivizumab group and in 1 subject in the lyophilized group. The true ADA percent positive, based on the upper limit of the 95% confidence interval (CI), was <1.5% for both treatments combined.

Conclusion

The frequency of detection of ADAs was low. The true ADA percent positive for both treatment groups combined based on the upper limit of the 95% CI was <1.5%. The type and frequency of SAEs reported were as expected, and there was no evidence of an increase in RSV disease with liquid palivizumab.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0033-y) contains supplementary material, which is available to authorized users.

A systematic review of risk factors associated with surgical site infections among surgical patients

IMPORTANCE

Surgical site infection (SSI) complicates 2-5% of surgeries in the United States. Severity of SSI ranges from superficial skin infection to life-threatening conditions such as severe sepsis, and SSIs are responsible for increased morbidity, mortality, and economic burden associated with surgery. Staphylococcus aureus (S. aureus) is a commonly-isolated organism for SSI, and methicillin-resistant S. aureus SSI incidence is increasing globally.

OBJECTIVE

The objective of this systematic review was to characterize risk factors for SSI within observational studies describing incidence of SSI in a real-world setting.

EVIDENCE REVIEW

An initial search identified 328 titles published in 2002-2012; 57 were identified as relevant for data extraction. Extracted information included study design and methodology, reported cumulative incidence and post-surgical time until onset of SSI, and odds ratios and associated variability for all factors considered in univariate and/or multivariable analyses.

FINDINGS

Median SSI incidence was 3.7%, ranging from 0.1% to 50.4%. Incidence of overall SSI and S. aureus SSI were both highest in tumor-related and transplant surgeries. Median time until SSI onset was 17.0 days, with longer time-to-onset for orthopedic and transplant surgeries. Risk factors consistently identified as associated with SSI included co-morbidities, advanced age, risk indices, patient frailty, and surgery complexity. Thirteen studies considered diabetes as a risk factor in multivariable analysis; 85% found a significant association with SSI, with odds ratios ranging from 1.5-24.3. Longer surgeries were associated with increased SSI risk, with a median odds ratio of 2.3 across 11 studies reporting significant results.

CONCLUSIONS AND RELEVANCE

In a broad review of published literature, risk factors for SSI were characterized as describing reduced fitness, patient frailty, surgery duration, and complexity. Recognition of risk factors frequently associated with SSI allows for identification of such patients with the greatest need for optimal preventive measures to be identified and pre-treatment prior to surgery.

Serious early childhood wheezing after respiratory syncytial virus lower respiratory tract illness in preterm infants

BACKGROUND

Respiratory syncytial virus (RSV) lower respiratory tract infection (LRI) in early life has been associated with sustained airway hyperreactivity during childhood; however, corresponding data in premature infants are sparse.

OBJECTIVE

The objective of this study was to determine whether RSV-LRI during early infancy of preterm infants was associated with an increased risk for serious early childhood wheezing (SECW) by age 3 years.

METHODS

A retrospective cohort study was conducted using data from a large (∼14 million members) US health plan database. The study population included infants ≤ 6 months of age born at ≤ 36 weeks' gestational age or weighing <2500 g, or both. Preterm infants with any medically attended RSV-LRI from May 2001 through April 2004 with 3 years of continuous eligibility were selected and propensity matched with ≤ 3 control infants. SECW was defined as >3 office, outpatient, or emergency department (ED) visits with asthma or wheezing; ≥ 1 office, outpatient, or ED visit with asthma or wheezing plus treatment with systemic corticosteroids within 7 days; ≥ 1 inpatient stay with asthma or wheezing; or ≥ 150 days' supply of asthma-control medications. The presence of SECW between ages 2 and 3 years was compared between infants with and without RSV-LRI using univariate and multivariate methods. Health care costs for patients with SECW were explored.

RESULTS

A total of 378 infants with RSV were matched to 606 controls. The prevalence of SECW between ages 2 and 3 years was 16.7% in the RSV-LRI group versus 8.6% in the control group (P < 0.001). Logistic regression showed that preterm infants with RSV in early life were 2.52-fold (95% CI,1.65-3.85) more likely to present with SECW between ages 2 and 3 years (P < 0.001). Patients with SECW had a mean SECW-related cost of US $1378 (95% CI, $939-$1816) and total health care cost of $7138 (95% CI, $5087-$9189) compared with $37 (95% CI, $24-$51) and $2521 (95% CI, $1789-$3253), respectively, for patients without SECW. After adjusting for possible confounders, patients with SECW had a significantly higher total health care cost than did patients without evidence of SECW (P < 0.001).

CONCLUSIONS

The development of RSV-LRI in infancy in preterm infants was associated with an increased prevalence of SECW between ages 2 and 3 years. Patients with SECW had higher total health care costs than those who did not have SECW.

Effect of dexamethasone on respiratory syncytial virus-induced lung inflammation in children: results of a randomized, placebo controlled clinical trial

Inflammatory mediators play a major role in the pathogenesis of respiratory syncytial virus (RSV) infection. The objective of this study was to evaluate the effect of i.v. dexamethasone on cytokine concentrations in tracheal aspirates (TA) of children with severe RSV disease and to correlate them with disease severity. Twenty-five cytokines were measured in TA obtained from children <2 yr old intubated for severe RSV disease, and enrolled in a double-blind study of i.v. dexamethasone (0.5 mg/kg; n = 22) vs. placebo (n = 19). Cytokine concentrations, measured at baseline and days 1 and 5 post-randomization using a multiplex assay, were compared within both treatment groups and correlated with: (i) tracheal white blood cell counts, (ii) tracheal RSV loads by culture and (iii) parameters of disease severity, including number of days of requirement for mechanical ventilation, intensive care unit (ICU), and hospitalization. At baseline interleukin (IL)-13 and IL-15 concentrations were significantly higher in the dexamethasone treatment group. On day 1 post-treatment, only MCP-1, eotaxin and IL-6 concentrations were significantly different but higher in the placebo group. On day 5: IL-13, IL-7, IL-8 and MIP-1alpha concentrations were higher in dexamethasone-treated patients. In both groups MIP-1beta inversely correlated with the days of ventilator support; MIP-1alpha, MIP-1beta and eotaxin inversely correlated with ICU days; and IL-6 inversely correlated with hospitalization regardless of the treatment assigned. Systemic administration of dexamethasone did not have a consistent effect on TA concentrations of pro-inflammatory cytokines. This may help explain, at least in part, the lack of clinical benefit of steroid treatment in children with severe RSV bronchiolitis.

A prospective, multicenter study of caspofungin for the treatment of documented Candida or Aspergillus infections in pediatric patients

OBJECTIVE

We evaluated the safety, tolerability, and efficacy of caspofungin in pediatric patients with invasive aspergillosis, invasive candidiasis, or esophageal candidiasis.

METHODS

This was a multicenter, prospective, open-label study in children 3 months to 17 years of age with proven or probable invasive aspergillosis, proven invasive candidiasis, or proven esophageal candidiasis. All of the patients received caspofungin 70 mg/m(2) on day 1, followed by 50 mg/m(2) per day (maximum: 70 mg/day), as primary or salvage monotherapy. Favorable response was defined as complete resolution of clinical findings and microbiologic (or radiographic/endoscopic) eradication (complete response) or significant improvement in these parameters (partial response). Efficacy was assessed at the end of caspofungin therapy in patients with a confirmed diagnosis who received >/=1 dose of caspofungin. The primary safety evaluation was the proportion of patients with clinical or laboratory drug-related adverse events.

RESULTS

Of the 49 patients enrolled, 3 were <2 years of age, 30 were 2 to 11 years of age, and 16 were 12 to 17 years of age. Forty-eight patients had confirmed disease: invasive aspergillosis (10), invasive candidiasis (37), and esophageal candidiasis (1). Eight of 10 patients with invasive aspergillosis had pulmonary involvement; 34 of 37 patients with invasive candidiasis had candidemia. Caspofungin was given for 2 to 87 days. Success at end of therapy was achieved in 5 of 10 patients with invasive aspergillosis, 30 of 37 with invasive candidiasis, and 1 of 1 with esophageal candidiasis. One patient (invasive candidiasis) relapsed during the 28-day follow-up period. Drug-related clinical or laboratory adverse events occurred in 27% and 35% of patients, respectively. There were no serious drug-related adverse events or discontinuations of caspofungin because of toxicity.

CONCLUSIONS

Caspofungin was generally well tolerated in pediatric patients aged 6 months through 17 years. Efficacy outcomes in patients with invasive aspergillosis or invasive candidiasis were consistent with previous adult studies in these indications.

Pharmacokinetics and pharmacodynamics of linezolid in children with cystic fibrosis

Alternative antimicrobial regimens are needed for treatment of methicillin-resistant Staphylococcus aureus (MRSA)-associated pulmonary exacerbations in children with cystic fibrosis (CF). There are no published pharmacokinetic (PK) and pharmacodynamic (PD) data for linezolid in children with CF.

OBJECTIVES

(1) To determine the PK and PD profile of linezolid among children with CF; (2) to characterize the effect of linezolid on MRSA infection; (3) to determine the effect of age and CF transmembrane regulator (CFTR) gene mutations on drug clearance.

HYPOTHESES

Linezolid clearance is enhanced in children with CF requiring a higher dosage regimen. Age and CFTR gene mutations affect drug clearance.

METHODS

This was a retrospective cohort study; medical records of children with MRSA-associated pulmonary exacerbations treated with linezolid (10 mg/kg/dose IV every 8h) were reviewed. Linezolid peak and trough concentrations in serum were determined by high performance liquid chromatography, PK profiles determined using standard noncompartmental method, and PD indices were evaluated.

RESULTS

10 children (mean +/- SD, 10.2 +/- 5.5 years) received 14 courses of linezolid at 10 +/- 0.4 mg/kg/dose every 8h for 15.4 +/- 3.2 days. Seven had homozygous DeltaF508 CFTR mutation. Peak and trough linezolid concentrations varied widely (range, 8.4-20.5 and 0.1-11.5 mcg/mL respectively). The PK profile of children <10 years differed significantly from older patients (>or=10 years). The PK indices of children with homozygous DeltaF508 differed marginally from those with heterozygous CFTR mutations, but there were too few subjects to allow separation of age and CFTR mutations effect. No patient achieved the target PD ratio of AUC/MIC >80. MRSA persisted in sputum or throat culture after treatment with linezolid.

CONCLUSIONS

Additional PK and PD data are needed to optimize linezolid therapy in children with cystic fibrosis; it is likely that higher doses will be needed.

Respiratory syncytial virus persistence in the lungs correlates with airway hyperreactivity in the mouse model

BACKGROUND

Previous studies in mice showed that respiratory syncytial virus (RSV) infection was associated with RSV RNA persistence. This study was designed to characterize the significance of RSV RNA persistence and its relation to RSV-induced chronic airway disease.

METHODS

Mice were inoculated with live RSV, UV light-treated RSV, heat-inactivated RSV, or medium. Bronchoalveolar lavage fluid samples were obtained and lung specimens were harvested on days 1, 5, and 42 after inoculation to assess lung inflammation, lung mRNA expression of interleukin (IL)-4, IL-5, IL-15, and interferon (IFN)-gamma; RSV loads were assessed by culture and real-time polymerase chain reaction (PCR) and correlated with pulmonary function.

RESULTS

During the acute phase of infection, RSV loads as indicated by culture and PCR were significantly higher in mice inoculated with live RSV. On day 42, RSV RNA remained detectable only in mice inoculated with live or UV light-treated RSV. Lung inflammation, IFN-gamma:IL-4 mRNA expression ratios, airway obstruction (AO), and airway hyperreactivity (AHR) were significantly increased in mice inoculated with live RSV. AO on day 5 and AHR on day 42 were significantly correlated with RSV RNA copy number in lung samples.

CONCLUSIONS

Infection with live RSV induced acute and chronic airway disease that was associated with a predominantly Th-1 immune response and RSV RNA persistence that significantly correlated with pulmonary function abnormalities.

Infliximab treatment of intravenous immunoglobulin-resistant Kawasaki disease

OBJECTIVE

To investigate the safety, tolerability, and pharmacokinetics of the anti-tumor necrosis factor-alpha monoclonal antibody infliximab in subjects with intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD).

STUDY DESIGN

We conducted a multicenter, randomized, prospective trial of second IVIG infusion (2 g/kg) versus infliximab (5 mg/kg) in 24 children with acute KD and fever after initial treatment with IVIG. Primary outcome measures were the safety, tolerability, and pharmacokinetics of infliximab. Secondary outcome measures were duration of fever and changes in markers of inflammation.

RESULTS

Study drug infusions were associated with cessation of fever within 24 hours in 11 of 12 subjects treated with infliximab and in 8 of 12 subjects retreated with IVIG. No infusion reactions or serious adverse events were attributed to either study drug. No significant differences were observed between treatment groups in the change from baseline for laboratory variables, fever, or echocardiographic assessment of coronary arteries.

CONCLUSIONS

Both infliximab and a second IVIG infusion were safe and well tolerated in the subjects with KD who were resistant to standard IVIG treatment. The optimal management of patients resistant to IVIG remains to be determined.

Diagnostic virology practices for respiratory syncytial virus and influenza virus among children in the hospital setting: a national survey

A survey was sent to the emergency room and laboratory directors of 400 randomly selected US hospitals to assess the diagnostic testing practices for respiratory syncytial virus and influenza virus in children. The results demonstrate that the majority of hospitals routinely perform viral testing for both viruses and use virology testing practices appropriate for the reasons reported for testing.

Successful medical treatment of cutaneous aspergillosis in a premature infant using liposomal amphotericin B, voriconazole and micafungin

Treatment options for primary cutaneous aspergillosis in neonates are limited by the lack of pharmacokinetic and safety data of newer antifungal agents that are effective against Aspergillus spp. We report the successful treatment of cutaneous aspergillosis in an extremely low-birth-weight preterm infant with liposomal amphotericin B, voriconazole and micafungin, and provide pharmacokinetic profiles for voriconazole and micafungin.

Effect of clarithromycin on cytokines and chemokines in children with an acute exacerbation of recurrent wheezing: a double-blind, randomized, placebo-controlled trial

BACKGROUND

Clarithromycin is postulated to possess immunomodulatory properties in addition to its antimicrobial activity.

OBJECTIVE

To evaluate the effect of clarithromycin on serum and nasopharyngeal cytokine and chemokine concentrations in children with an acute exacerbation of recurrent wheezing.

METHODS

Children with a history of recurrent wheezing or asthma and who presented with an acute exacerbation of wheezing were enrolled in a double-blind, randomized trial of clarithromycin vs placebo. Concentrations of tumor necrosis factor alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, RANTES, eotaxin, macrophage inflammatory protein 1alpha, macrophage inflammatory protein 1beta, and monocyte chemoattractant protein 1 were measured in serum and/or nasopharyngeal aspirates before, during, and after therapy. Mycoplasma pneumoniae and Chlamydophila pneumoniae infection were evaluated for by polymerase chain reaction and serologic testing.

RESULTS

Nasopharyngeal concentrations of TNF-alpha, IL-1beta, and IL-10 were significantly and persistently lower in children treated with clarithromycin compared with placebo. There tended to be a greater effect of clarithromycin on nasopharyngeal cytokine concentrations in patients with evidence of M. pneumoniae or C. pneumoniae infection. No significant differences were detected in serum cytokines for children treated with clarithromycin compared with placebo.

CONCLUSION

Clarithromycin therapy reduces mucosal TNF-alpha, IL-1beta, and IL-10 concentrations in children with an acute exacerbation of recurrent wheezing.

Temporal arteritis presenting with gastrointestinal symptoms in a middle aged man

Giant cell arteritis, also known as temporal arteritis, is a vasculitis of unknown etiology that classically involves the wall of the large to medium size. We are reporting a case of a young onset temporal arteritis presenting with gastrointestinal symptoms. The patient was a 48-year-old male who presented with a 2-week history of fever, diffuse abdominal pain, and malaise. He underwent a laparoscopic cholecystectomy after findings of elevated bilirubin and alkaline phosphatase as well as suspicion of porcelain gallbladder on ultrasound (or computed tomography scan). The patient subsequently developed painless, intermittent vision loss and unilateral headaches. A work-up included temporal artery biopsy, which showed marked lymphocytic infiltrate in the arterial wall consistent with temporal arteritis. The presentation of temporal arteritis may be atypical. We are reporting a case of temporal arteritis at a young age presenting mainly with gastrointestinal symptoms.

Antibiotic therapy for nontuberculous mycobacterial cervicofacial lymphadenitis

OBJECTIVES/HYPOTHESIS

To evaluate the efficacy of antibiotic treatment of nontuberculous mycobacterial (NTM) cervicofacial lymphadenitis, both as an alternative and as adjuvant to surgical excision.

STUDY DESIGN

Retrospective chart review of pediatric patients with NTM cervicofacial lymphadenitis treated from January 1993 to November 2003 at an academic tertiary care children's hospital.

METHODS

Fifty-five patients (age range, 15 mo-16 y) with the diagnosis of NTM cervicofacial lymphadenitis by fine-needle aspiration biopsy that had 1) lymph node culture positive for an atypical mycobacteria, 2) histological findings consistent with mycobacterial infection (granulomas) with negative bartonella serological titers, 3) histological stain positive for the presence of acid-fast bacillus in the absence of tuberculous infection, or 4) positive Mantoux tuberculin skin test result with a negative finding on polymerase chain reaction for tuberculous mycobacteria. Clinical response was defined as complete or partial resolution of skin changes and palpable lymphadenopathy in response to antibiotic therapy consisting of macrolide therapy alone or in combination with other anti-mycobacterial pharmaceuticals.

RESULTS

Of the 55 children studied, 45 of 55 (82%) with both single and multiple lesions underwent a trial of medical therapy, and 30 of 45 lesions (67%) ranging in size from 1 x 1 to 6 x 5 cm achieved resolution without surgical excision. Of the other 15 patients treated initially with medical therapy, 6 of 15 (40%) responded well to a course of antibiotic therapy before undergoing surgical excision, and 7 of 15 (47%) patients were nonresponsive to antibiotic therapy and required surgical excision to resolve the neck mass. The remaining 2 of 15 patients (13%) proceeded to surgery only after a course of antibiotics of 3 weeks or less. Ten of the 55 patients (18%) underwent surgical excision initially, with 5 of 10 patients (50%) receiving postoperative antibiotics for treatment of residual disease or prevention of recurrence.

CONCLUSION

Some NTM cervicofacial lymphadenitis infections appear to respond to medical therapy alone. A trial of antibiotic therapy might be considered in patients with NTM cervicofacial lymphadenitis before surgical excision or as an adjuvant to surgical excision.

Comparative effects of two neutralizing anti-respiratory syncytial virus (RSV) monoclonal antibodies in the RSV murine model: time versus potency

Respiratory syncytial virus (RSV) is the leading viral pathogen responsible for bronchiolitis and pneumonia in infants and young children worldwide. We have previously shown in the mouse model that treatment with an anti-RSV neutralizing monoclonal antibody (MAb) against the F glycoprotein of RSV, palivizumab, decreased lung inflammation, airway obstruction, and postmethacholine airway hyperresponsiveness. MEDI-524, or Numax, is a new MAb derived from palivizumab with enhanced neutralizing activity against RSV. We compared the effects of these two MAbs on different markers of disease severity using the murine model of RSV infection. BALB/c mice were intranasally inoculated with RSV A2. Palivizumab or MEDI-524 was administered once at either 24 h before or 48 h after RSV inoculation. Regardless of the time of administration, all treated mice showed significantly decreased RSV loads in bronchoalveolar lavage samples measured by plaque assay. Only MEDI-524 given at -24 h significantly decreased lung RSV RNA loads on days 5 and 28 after RSV inoculation. Pulmonary histopathologic scores, airway obstruction, and postmethacholine airway hyperresponsiveness were significantly reduced in mice treated with MEDI-524 at 24 h before inoculation, compared with untreated controls and the other regimens evaluated. MEDI-524 was superior to palivizumab on several outcome variables of RSV disease assessed in the mouse model: viral replication, inflammatory and clinical markers of acute disease severity, and long-term pulmonary abnormalities.

Respiratory syncytial virus infections: old challenges and new opportunities

BACKGROUND

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis and pneumonia among children aged < 1 year. The majority of children hospitalized for RSV infection are younger than 6 months of age. RSV also causes repeated infections including severe lower respiratory tract disease, which may occur at any age, especially among the elderly or those with compromised cardiac, pulmonary, or immune systems.

METHODS

Using the mouse model of RSV infection, this article examines the immunopathogenesis during acute and chronic phases of the disease. This model allows for measurement of basal enhanced pause, which reflects airway obstruction in the acute phase, and the response to methacholine challenge to assess airway hyperresponsiveness during the chronic phase. This article also summarizes some recent studies focusing on novel perspectives and strategies for treatment and prevention of RSV infections.

RESULTS

Compared with the lungs of sham-inoculated control mice, mice inoculated with live RSV showed a persistent progression of the severity of pneumonia as determined by an increasing histopathologic score. Mucus production of RSV-infected mice in the acute phase illustrated increased periodic acid-Schiff-positive hypertrophic cells in central and peripheral airways.

CONCLUSIONS

RSV-infected mice with persistent airway hyperresponsiveness exhibited the presence of abnormal chronic inflammatory changes and mucus overproduction, which likely contributed to long term airway disease induced by RSV infection. These findings provide a histologic correlation to the abnormal pulmonary responses documented by plethysmography. Current trials have demonstrated positive results in continuing to target different alternatives for a new RSV vaccine.

Respiratory syncytial virus-induced acute and chronic airway disease is independent of genetic background: an experimental murine model

Background

Respiratory syncytial virus (RSV) is the leading respiratory viral pathogen in young children worldwide. RSV disease is associated with acute airway obstruction (AO), long-term airway hyperresponsiveness (AHR), and chronic lung inflammation. Using two different mouse strains, this study was designed to determine whether RSV disease patterns are host-dependent. C57BL/6 and BALB/c mice were inoculated with RSV and followed for 77 days. RSV loads were measured by plaque assay and polymerase chain reaction (PCR) in bronchoalveolar lavage (BAL) and whole lung samples; cytokines were measured in BAL samples. Lung inflammation was evaluated with a histopathologic score (HPS), and AO and AHR were determined by plethysmography.

Results

Viral load dynamics, histopathologic score (HPS), cytokine concentrations, AO and long-term AHR were similar in both strains of RSV-infected mice, although RSV-infected C57BL/6 mice developed significantly greater AO compared with RSV-infected BALB/c mice on day 5. PCR detected RSV RNA in BAL samples of RSV infected mice until day 42, and in whole lung samples through day 77. BAL concentrations of cytokines TNF-α, IFN-γ, and chemokines MIG, RANTES and MIP-1α were significantly elevated in both strains of RSV-infected mice compared with their respective controls. Viral load measured by PCR significantly correlated with disease severity on days 14 and 21.

Conclusion

RSV-induced acute and chronic airway disease is independent of genetic background.

Herpes simplex virus encephalitis during suppressive therapy with acyclovir in a premature infant

Cutaneous herpes simplex virus type 2 (HSV-2) infection was recognized at 19 days of age in a 1415-g female infant born at 31 weeks of gestation. Cerebrospinal fluid (CSF) HSV polymerase chain reaction (PCR) was negative, and MRI of the brain was normal. After a 14-day course of high-dose intravenous acyclovir, the infant developed a cutaneous recurrence at 38 days of age. CSF HSV PCR again was negative. She was subsequently begun on oral acyclovir to prevent cutaneous reactivation of HSV. At 3 months of age, the infant developed HSV encephalitis as manifested by fever, seizures, abnormal CSF indices, abnormal brain MRI, and positive CSF HSV PCR. No cutaneous disease was present. It is not known whether the HSV encephalitis in our patient represented reactivation of previously unrecognized central nervous system infection or new onset of central nervous system disease as a result of spread from other tissue or site to the brain. The failure of oral acyclovir to prevent such an occurrence, however, highlights gaps in our understanding of the pathogenesis of neonatal HSV disease and questions the use of acyclovir suppression to prevent neurologic sequelae.

[Asthma and respiratory syncytial virus. New opportunities for therapeutic intervention]

Numerous studies have described an association between respiratory sincticial virus (RSV) infection in infancy and the subsequent development of airway hyperresponsiveness (AHR). Besides the exaggerated immune response and the abnormal neurogenic mechanisms induced by RSV, recent studies have correlated the "persistence" of RSV in the lower respiratory tract with the development of AHR. Several investigators have evaluated whether treatment with antiviral or immunosuppressive agents could decrease the long term respiratory abnormalities induced by RSV. The RSV murine model has allowed us to study the immunopathogenesis of RSV-induced AHR. Once the airway obstruction, typical of acute disease, is resolved and no virus is longer detected by cell cultures, mice progress into a chronic phase characterized by AHR and persistent airway inflammation. The use of polymerase chain reaction assay for RSV quantitation has demonstrated, quite unexpectedly, the presence of RSV RNA in the lower respiratory tract of mice during the chronic phase of the disease. As an example of intervention, the administration of an anti-RSV neutralizing antibody (palivizumab) was associated with a significant reduction in viral replication, pulmonary inflammation and inflammatory cytokines, as well as a significant improvement in the pulmonary function both in the acute and chronic phases of the disease. Future clinical studies to determine whether therapy with palivizumab can prevent the long-term morbidity associated with RSV in children are warranted.

Respiratory syncytial virus: old challenges and new approaches

Better therapies and prevention strategies are needed to decrease the burden of acute RSV disease in all age populations worldwide. Furthermore, we can hypothesize that those improved measures also would likely have an effect on the chronic consequences of RSV infection in children and will reduce the incidence of recurrent wheezing and persistent pulmonary function abnormalities caused by RSV LRIs.

Impact of cethromycin (ABT-773) therapy on microbiological, histologic, immunologic, and respiratory indices in a murine model of Mycoplasma pneumoniae lower respiratory infection

Mycoplasma pneumoniae is a major etiologic agent of acute lower respiratory infections. We evaluated the antimicrobial and immunologic effects of cethromycin (ABT-773), a ketolide antibiotic, for the treatment of M. pneumoniae pneumonia in a mouse model. Eight-week-old BALB/c mice were inoculated intranasally once with 10(6) CFU of M. pneumoniae on day 0. Treatment was started 24 h after inoculation. Groups of mice were treated subcutaneously with cethromycin at 25 mg/kg of body weight or with placebo daily until sacrifice. Five to ten mice per group were evaluated at days 1, 4, 7, and 10 after inoculation. Outcome variables included bronchoalveolar lavage (BAL) for M. pneumoniae quantitative culture and cytokine and chemokine concentration determinations by enzyme-linked immunosorbent assay (tumor necrosis factor alpha [TNF-alpha], gamma interferon [IFN-gamma], interleukin-1beta [IL-1beta], IL-2, IL-4, IL-12, granulocyte-macrophage colony-stimulating factor, IL-8, monocyte chemoattractant protein 1 [MCP-1], and macrophage inflammatory protein 1alpha [MIP-1alpha]), histopathologic score of the lungs (HPS), and pulmonary function tests (PFT) using whole-body, unrestrained plethysmography at the baseline and post-methacholine exposure as indicators of airway obstruction (AO) and airway hyperresponsiveness (AHR), respectively. The cethromycin-treated mice had a greater reduction in M. pneumoniae culture titers than placebo-treated mice, reaching statistical significance on days 7 and 10 (P < 0.05). HPS was significantly reduced in cethromycin-treated mice compared with placebo-treated mice on days 4, 7, and 10 (P < 0.05). Cytokine concentrations in BAL samples were reduced in mice that received cethromycin, and the differences were statistically significant for 7 of the 10 cytokines measured (TNF-alpha, IFN-gamma, IL-1beta, IL-8, IL-12, MCP-1, and MIP-1alpha) on day 4 (P < 0.05). PFT values were improved in the cethromycin-treated mice, with AO and AHR significantly reduced on day 4 (P < 0.05). In this mouse model, treatment with cethromycin significantly reduced M. pneumoniae culture titers in BAL samples, cytokine and chemokine concentrations in BAL samples, histologic inflammation in the lungs, and disease severity as defined by AO and AHR.

Anti-respiratory syncytial virus (RSV) neutralizing antibody decreases lung inflammation, airway obstruction, and airway hyperresponsiveness in a murine RSV model

Numerous studies have described a strong association between respiratory syncytial virus (RSV) infection in infancy and the development of recurrent wheezing and airway hyperresponsiveness. We evaluated the effect of an anti-RSV neutralizing monoclonal antibody (palivizumab) on different aspects of RSV disease by using a murine model. BALB/c mice were intranasally inoculated with RSV A2. Palivizumab or an isotype-matched control antibody was administered once at 24 h before inoculation, 1 h after inoculation, or 48 h after inoculation. Regardless of the timing of administration, all mice treated with the neutralizing antibody showed significantly decreased RSV loads in bronchoalveolar lavage (BAL) and lung specimens compared with those of infected controls. Pulmonary histopathologic scores, airway obstruction measured by plethysmography, and airway hyperresponsiveness after methacholine challenge were significantly reduced in mice treated with the anti-RSV antibody 24 h before inoculation compared with those for untreated controls. Concentrations of interferon-gamma, interleukin-10, macrophage inflammatory protein 1alpha, regulated on activation normal T-cell expressed and secreted (RANTES), and eotaxin in BAL fluids were also significantly reduced in mice treated with palivizumab 24 h before inoculation. This study demonstrates that reduced RSV replication was associated with significant modulation of inflammatory and clinical markers of acute disease severity and significant improvement of the long-term pulmonary abnormalities. Studies to determine whether strategies aimed at preventing or reducing RSV replication could decrease the long-term morbidity associated with RSV infection in children should be considered.

Respiratory syncytial virus induces pneumonia, cytokine response, airway obstruction, and chronic inflammatory infiltrates associated with long-term airway hyperresponsiveness in mice

BACKGROUND

Respiratory syncytial virus (RSV) infection is associated with acute morbidity (e.g., pneumonia and airway obstruction [AO]) and long-term complications (e.g., airway hyperresponsiveness [AHR]). We present a comprehensive evaluation of the acute and chronic phases of RSV respiratory tract infection, using a mouse model.

METHODS

BALB/c mice were inoculated with RSV and monitored for 154 days. RSV loads and cytokines were measured in bronchoalveolar lavage (BAL) samples. Pneumonia severity was assessed using a standard histopathologic score, and pulmonary function was determined by plethysmography.

RESULTS

RSV-infected mice exhibited viral replication that peaked on day 4-5 and became undetectable by day 7. These mice developed acute pneumonia (peak days, 4-5) and chronic pulmonary inflammatory infiltrates that lasted up to 154 days after inoculation. BAL concentrations of tumor necrosis factor- alpha, interleukin (IL)-6, interferon- gamma, IL-4, IL-10, KC (an IL-8 homologue), MIG (CXCL9), RANTES, macrophage inflammatory protein-1 alpha, and eotaxin were significantly higher in RSV-infected mice than in control mice. RSV-infected mice developed acute AO during the first week of infection that persisted for 42 days. RSV-infected mice also showed significant AHR in response to methacholine up to 154 days.

CONCLUSION

This model provides a means to investigate the immunopathogenesis of RSV infection and its association with reactive airway disease.

Factors influencing the anti-inflammatory effect of dexamethasone therapy in experimental pneumococcal meningitis

Dexamethasone (DXM) interferes with the production of tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) and can thereby diminish the secondary inflammatory response that follows initiation of antibacterial therapy. A beneficial effect on the outcome of Haemophilus meningitis in children has been proven, but until recently the effect of DXM therapy in pneumococcal meningitis was uncertain. The aim of the present study was to evaluate factors that might influence the modulatory effect of DXM on the antibiotic-induced inflammatory response in a rabbit model of pneumococcal meningitis. DXM (1 mg/kg) was given intravenously 30 min before or 1 h after administration of a pneumococcal cell wall extract, or the first dose of ampicillin. In meningitis induced by cell wall extract, DXM therapy prevented the increase in cerebrospinal fluid (CSF) leucocyte and lactate concentrations, but only if given 30 min before the cell wall extract. In meningitis caused by live organisms, initiation of ampicillin therapy resulted in an increase in CSF TNF-alpha and lactate concentrations only in animals with initial CSF bacterial concentrations > or =5.6 log10 cfu/mL. In those animals, DXM therapy prevented significant elevations in CSF TNF-alpha [median change -184 pg/mL, -114 pg/mL versus +683 pg/mL with DXM (30 min before or 1 h after ampicillin) versus controls (no DXM), respectively, P=0.02] and lactate concentrations [median change -10.6 mmol/L, -1.5 mmol/L versus +14.3 mmol/L with DXM (30 min before or 1 h after ampicillin) versus controls (no DXM), respectively, P=0.01]. These effects were independent of the timing of DXM administration. In this model of experimental pneumococcal meningitis, an antibiotic-induced secondary inflammatory response in the CSF was demonstrated only in animals with high initial CSF bacterial concentrations (> or =5.6 log10 cfu/mL). These effects were modulated by DXM therapy whether it was given 30 min before or 1 h after the first dose of ampicillin.

Antimicrobial and immunologic activities of clarithromycin in a murine model of Mycoplasma pneumoniae-induced pneumonia

Because macrolide antibiotics are hypothesized to possess immunomodulatory activity independent of their antimicrobial activity, we evaluated the immunomodulatory effect of clarithromycin in a murine model of lung inflammation induced by either live or UV-killed Mycoplasma pneumoniae. BALB/c mice were intranasally inoculated once with live or UV-killed M. pneumoniae. Clarithromycin (25 mg/kg of body weight) or placebo was subcutaneously administered once daily in both groups of mice. In mice infected with live M. pneumoniae, clarithromycin treatment significantly reduced quantitative M. pneumoniae bronchoalveolar lavage (BAL) culture, pulmonary histopathologic scores (HPS), and airway resistance-obstruction (as measured by plethysmography) compared with placebo. Concentrations of tumor necrosis factor alpha, gamma interferon, interleukin-6 (IL-6), mouse KC (functional IL-8), JE/MCP-1, and MIP-1alpha in BAL fluid were also significantly decreased in mice infected with live M. pneumoniae given clarithromycin. In contrast, mice inoculated with UV-killed M. pneumoniae had no significant reduction in HPS, airway resistance-obstruction, or BAL cytokine or chemokine concentrations in response to clarithromycin administration. Clarithromycin therapy demonstrated beneficial effects (microbiologic, histologic, respiratory, and immunologic) on pneumonia in the mice infected with live M. pneumoniae; this was not observed in the mice inoculated with UV-killed M. pneumoniae.

Treatment of respiratory syncytial virus: antiviral therapies

Treatment of respiratory syncytial virus (RSV) in infants with bronchiolitis is complicated because of the multifactorial nature of this infection. The signs and symptoms of RSV result from a combination of direct viral cytopathic effects, host inflammatory responses that lead to airway obstruction and bronchoconstriction. It is logical that therapies targeting just one of these processes might be minimally effective, at best. Thus an important goal is to identify patients at risk and intervene to prevent disease, whenever possible. Once disease has been identified, the clinician must decide whether antiviral therapy is appropriate. Familiarity with typical viral load dynamics during the course of a lower respiratory tract infection can assist in the therapeutic decision process. For example in a patient who has had airway obstruction and other respiratory symptoms for >3 days, viral load has already peaked. Clearly this pattern has important implications for antiviral therapies.Preventive strategies include educating parents and family about hand washing, cleaning environmental surfaces, isolating infants and children with infection and avoiding crowded places such as busy day-care centers. High risk patients, who meet the American Academy of Pediatrics criteria for RSV prophylaxis, may be candidates for passive prophylaxis.

Clinical chorioamnionitis, elevated cytokines, and brain injury in term infants

OBJECTIVES

To determine the initial inflammatory cytokine response in term infants born to mothers with clinical chorioamnionitis and to assess whether the cytokine response is associated with birth depression, abnormal neurologic examination, and hypoxic-ischemic encephalopathy (HIE).

METHODS

Infants who were exposed to chorioamnionitis and admitted to the neonatal intensive care unit (n = 61) were studied prospectively. Cytokine concentrations were measured from umbilical cord blood and at 6 and 30 hours after birth. Control values (n = 50) were determined from cord blood of healthy term infants. Enzyme-linked immunosorbent assays were performed for interleukin (IL)-1beta; IL-6; IL-8; regulated on activation, normal T-cell expressed and secreted (RANTES); macrophage inflammatory protein-1alpha; and tumor necrosis factor-alpha. Serial blinded neurologic examinations using a modified Dubowitz score were performed simultaneously at 6 and 30 hours.

RESULTS

Cord IL-6 (1071 +/- 1517 vs 65 +/- 46 pg/mL), IL-8 (2580 +/- 9834 vs 66 +/- 57 pg/mL), and RANTES (95 917 +/- 16 518 vs 54 000 +/- 14 306 pg/mL) concentrations only were higher in infants with chorioamnionitis versus control infants. IL-6 increased at 6 hours to 1451 +/- 214 pg/mL, followed by a 5-fold decline at 30 hours in contrast to progressive decreases over time in IL-8 and RANTES. There was no relationship between cytokines and birth depression. Modified Dubowitz score correlated with IL-6 at 6 hours (r = 0.5). Infants with HIE/seizures (n = 5) had significantly higher cytokine concentrations at 6 hours versus infants without either (n = 56): IL-6 (3130 vs 1219 pg/mL), IL-8 (5433 vs 780 pg/mL), and RANTES (97 396 vs 46 914 pg/mL).

CONCLUSIONS

There was a significant association between abnormalities in the neurologic examination and cytokine concentrations, with the highest cytokines concentrations observed in infants who developed HIE/seizures.

A randomized, double-blind, placebo-controlled trial of dexamethasone in severe respiratory syncytial virus (RSV) infection: effects on RSV quantity and clinical outcome

Forty-one previously healthy children <2 years of age who required mechanical ventilation for respiratory syncytial virus (RSV) infection were randomized to receive dexamethasone (0.5 mg/kg; n=22) or saline placebo (n=19) intravenously every 12 h for 4 days. RSV quantity was measured by quantitative plaque assay in fresh tracheal and nasal aspirates obtained at intervals of 24+/-3 h on days 0, 1, 2, 5, and 7 following entry. Analysis by linear mixed-effects modeling demonstrated a significantly greater decline in mean tracheal RSV quantity in the placebo group than in the dexamethasone group from day 0 to day 1 (0.82 vs. 0.21 log pfu/mL; P=.01) and from day 0 to day 2 (1.45 vs. 0.53 log pfu/mL; P=.03). No differences were found between groups in nasal RSV quantity, white blood cell counts in tracheal or nasal aspirates, serum neutralizing antibody titers during convalescence, or duration of mechanical ventilation, intensive care unit stay, or hospital stay.

Mycoplasma pneumoniae induces chronic respiratory infection, airway hyperreactivity, and pulmonary inflammation: a murine model of infection-associated chronic reactive airway disease

Because chronic Mycoplasma pneumoniae respiratory infection is hypothesized to play a role in asthma, the potential of M. pneumoniae to establish chronic respiratory infection with associated pulmonary disease was investigated in a murine model. BALB/c mice were intranasally inoculated once with M. pneumoniae and examined at 109, 150, 245, 368, and 530 days postinoculation. M. pneumoniae was detected in bronchoalveolar lavage fluid by culture or PCR in 70 and 22% of mice at 109 and 530 days postinoculation, respectively. Lung histopathology was normal up to 368 days postinoculation. At 530 days, however, 78% of the mice inoculated with M. pneumoniae demonstrated abnormal histopathology characterized by peribronchial and perivascular mononuclear infiltrates. A mean histopathologic score (HPS) at 530 days of 5.1 was significantly greater (P < 0.01) than that for controls (HPS score of 0). Serum anti-M. pneumoniae immunoglobulin G was detectable in all of the mice inoculated with M. pneumoniae and was inversely correlated with HPS (r = -0.95, P = 0.01) at 530 days postinoculation. Unrestrained whole-body plethysmography measurement of enhanced pause revealed significantly elevated airway methacholine reactivity in M. pneumoniae-inoculated mice compared with that in controls at 245 days (P = 0.03) and increased airway obstruction at 530 days (P = 0.01). Murine M. pneumoniae respiratory infection can lead to chronic pulmonary disease characterized by airway hyperreactivity, airway obstruction, and histologic inflammation.

Pharmacodynamics and bactericidal activity of moxifloxacin in experimental Escherichia coli meningitis

Moxifloxacin, an 8-methoxyquinolone with broad-spectrum activity in vitro, was studied in the rabbit model of Escherichia coli meningitis. The purposes of this study were to evaluate the bactericidal effectiveness and the pharmacodynamic profile of moxifloxacin in cerebrospinal fluid (CSF) and to compare the bactericidal activity with that of ceftriaxone and meropenem therapy. After induction of meningitis, animals were given single doses of 10, 20, and 40 mg/kg or divided-dose regimens of 5, 10, and 20 mg/kg twice, separated by 6 h. After single doses, the penetration of moxifloxacin into purulent CSF, measured as percentage of the area under the concentration-time curve (AUC) in CSF relative to the AUC in plasma, was approximately 50%. After single doses of 10, 20, and 40 mg/kg, the maximum CSF concentration (C(max)) values were 1.8, 4.2, and 4.9 microg/ml, respectively; the AUC values (total drug) were 13.4, 25.4, and 27.1 microg/ml x h, respectively, and the half-life values (t(1/2)) were 6.7, 6.6, and 4.7 h, respectively. The bacterial killing in CSF for moxifloxacin, calculated as the Deltalog(10) CFU per milliliter per hour, at 3, 6, and 12 h after single doses of 10, 20, and 40 mg/kg were -5.70, -6.62, and -7.02; -7.37, -7.37, and -6.87; and -6.62, -6.62, and -6.62, respectively, whereas those of ceftriaxone and meropenem were -4.18, -5.24, and -4.43, and -3.64, -3.59, and -4.12, respectively. The CSF pharmacodynamic indices of AUC/MBC and C(max)/MBC were interrelated (r = 0.81); there was less correlation with T > MBC (r = 0.74). In this model, therapy with moxifloxacin appears to be at least as effective as ceftriaxone and more effective than meropenem therapy in eradicating E. coli from CSF.

Elevated cytokine and chemokine levels and prolonged pulmonary airflow resistance in a murine Mycoplasma pneumoniae pneumonia model: a microbiologic, histologic, immunologic, and respiratory plethysmographic profile

Because Mycoplasma pneumoniae is hypothesized to play an important role in reactive airway disease/asthma, a comprehensive murine model of M. pneumoniae lower respiratory infection was established. BALB/c mice were intranasally inoculated once with M. pneumoniae and sacrificed at 0 to 42 days postinoculation. All mice became infected and developed histologic evidence of acute pulmonary inflammation, which cleared by 28 days postinoculation. By contrast, M. pneumoniae persisted in the respiratory tract for the entire 42 days studied. Tumor necrosis factor alpha, gamma interferon, interleukin-6 (IL-6), KC (functional IL-8), MIP-1alpha, and MCP-1/JE concentrations were significantly elevated in bronchoalveolar lavage samples, whereas IL-4 and IL-10 concentrations were not significantly elevated. Pulmonary airflow resistance, as measured by plethysmography, was detected 1 day postinoculation and persisted even after pulmonary inflammation had resolved at day 28. Serum anti-M. pneumoniae immunoglobulin G titers were positive in all mice by 35 days. This mouse model provides a means to investigate the immunopathogenesis of M. pneumoniae infection and its possible role in reactive airway disease/asthma.

Fluoroquinolones in paediatrics

Fluoroquinolones have a broad spectrum of activity against gram-positive, gram-negative, and mycobacterial organisms as well as anaerobes, Mycoplasma, Chlamydia, Ureaplasma, and Legionella spp. They have excellent oral bioavailability, with good tissue penetration, and long elimination half-lives. The experience with fluoroquinolones in paediatrics has been limited because of concerns about arthropathy, based on findings in animal models. However, there has not been a definitive fluoroquinolone-associated case of arthropathy described in the literature. We believe that there are a number of specific paediatric infections in which the clinical efficacy and tolerability of the fluoroquinolones should be further investigated. These include patients with cystic fibrosis who have repeated infections with Pseudomonas spp., patients with pseudomonal and other gram-negative infections such as urinary tract infections and osteomyelitis, and febrile neutropenic patients. Meningeal infections caused by multiple drug-resistant Streptococcus pneumoniae and gram-negative organisms, gastroenteritis due to enteric pathogens, and mycobacterial infections are other potential conditions where fluoroquinolones should be studied in paediatric patients.

Enzyme-linked immunosorbent assay to assess respiratory syncytial virus concentration and correlate results with inflammatory mediators in tracheal secretions

OBJECTIVE

We developed an enzyme-linked immunosorbent assay (ELISA) for the quantitation of respiratory syncytial virus (RSV) in respiratory secretions in intubated patients infected with RSV.

METHODS

We compared the quantitative ELISA and a standardized plaque assay in intubated children <2 years of age who were mechanically ventilated for severe RSV disease and enrolled in a randomized double blind placebo-controlled treatment trial of a monoclonal antibody to the F protein of RSV (palivizumab; Synagis). We also examined the relationship between the concentrations of virus as measured by ELISA and of three inflammatory indices in respiratory secretions (white blood cell count, myeloperoxidase and eosinophilic cationic protein).

RESULTS

Quantitative ELISA and plaque assay were highly correlated for both tracheal aspirates (r = 0.67, P = 0.001) and nasal wash specimens (r = 0.75, P = 0.001). Treatment with palivizumab significantly neutralized RSV in tracheal aspirates as measured by plaque assay. In contrast quantitation of RSV by ELISA was not affected by palivizumab treatment. This finding is consistent with results that were obtained in preliminary studies of RSV-containing media treated with monoclonal antibody, where we found that the ELISA measured virus whether antibody-bound or not. The inflammatory indices were not correlated with RSV concentration measured by ELISA or plaque assay.

CONCLUSIONS

We conclude that this quantitative ELISA is a potentially useful tool for measurement of RSV concentration in respiratory secretions that may help elucidate the pathophysiology of acute RSV infection. Specific antiviral strategies for the treatment of RSV disease could be evaluated by this method.