The use of extrapolation based on modeling and simulation to support high-dose regimens of ceftaroline fosamil in pediatric patients with complicated skin and soft-tissue infections

A model-informed drug development approach was used to select ceftaroline fosamil high-dose regimens for pediatric patients with complicated skin and soft-tissue infections caused by Staphylococcus aureus with a ceftaroline minimum inhibitory concentration (MIC) of 2 or 4 mg/L. Steady-state ceftaroline concentrations were simulated using a population pharmacokinetics (PK) model for ceftaroline fosamil and ceftaroline including data from 304 pediatric subjects and 944 adults. Probability of target attainment (PTA) for various simulated pediatric high-dose regimens and renal function categories were calculated based on patients achieving 35% fT>MIC (S. aureus PK/pharmacodynamic target for 2-log10 bacterial killing). For extrapolation of efficacy, simulated exposures and PTA were compared to adults with normal renal function receiving high-dose ceftaroline fosamil (600 mg 2-h infusions every 8 h). For safety, predicted ceftaroline exposures were compared with observed pediatric and adult data. Predicted ceftaroline exposures for the approved pediatric high-dose regimens (12, 10, or 8 mg/kg by 2-h infusions every 8 h for patients aged >2 to <18 years with normal/mild, moderate, or severe renal impairment, respectively; 10 mg/kg by 2-h infusions every 8 h for patients aged ≥2 months to <2 years with normal renal function/mild impairment) were well matched to adults with normal renal function. Median predicted maximum concentration at steady state (Cmax,ss ) and area under the plasma concentration-time curve over 24 h at steady state pediatric to adult ratios were 0.907-1.33 and 0.940-1.41, respectively. PTAs (>99% and ≥81% for MICs of 2 and 4 mg/L, respectively) matched or exceeded the adult predictions. Simulated Cmax,ss values were below the maximum observed data in other indications, including a high-dose pediatric pneumonia trial, which reported no adverse events related to high exposure.

Serum insulin-like growth factor-I (IGF-I), IGF-binding protein-3, and growth hormone levels in collodion babies: a case-control study

AIM

Because growth failure occurs in many collodion babies, we investigated serum growth hormone (GH), insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) levels in collodion babies admitted to Gevher Nesibe Hospital, Kayseri, Turkey between 1999 and 2006.

PATIENTS AND METHOD

The newborns diagnosed clinically as 'collodion baby' were included in the study group (group 1). Because collodion babies are usually born small for gestational age (SGA) and/or premature, a control group (group 2) was formed by selecting the first infant admitted immediately after each study infant who matched for gestational age (+/- 7 days) and birth weight (+/- 100 g). All infants' blood samples were collected within the first 2 h of life for measurements of serum GH, IGFBP-3 and IGF-I levels.

RESULTS

Group 1 consisted of 23 collodion babies (13 males and 10 females) with gestational ages ranging from 32 to 42 weeks, and birth weights ranging from 1,300 to 3,600 g. Ten were born premature and 16 were SGA. Serum IGF-I and IGFBP-3 levels were lower but serum GH levels were higher in collodion babies than in controls. Birth weight was positively correlated with serum IGF-I (r = 0.310, p = 0.046) and IGFBP-3 (r = 0.389, p = 0.011) levels. Serum GH level was negatively correlated with birth weight (r = -0.376, p = 0.014), serum IGF-I (r = -0.567, p <0.001) and IGFBP-3 (r = -0.444, p = 0.003).

CONCLUSION

Collodion babies had lower serum IGF-I and IGFBP-3 levels but higher serum GH levels than controls in the present case-control study. The underlying mechanism needs to be explored.

High serum hepatocyte growth factor levels in the acute stage of community-acquired infectious diseases

Acute serum levels of hepatocyte growth factor (HGF) were studied in 6 clinical groups with (i) gastroenteritis, (ii) skin and soft tissue infection, (iii) urinary tract infection, (iv) septicemia, (v) influenza, and (vi) chronic hepatitis C in comparison with a normal control group using an enzyme-linked immunosorbent assay method. We found that serum HGF levels were significantly higher in patients with acute infectious diseases (p < 0.0001) compared to patients with chronic viral hepatitis and healthy controls. Serum HGF and CRP levels were correlated significantly (r=0.65, p < 10(-7)). We conclude that serum HGF levels are elevated in patients with acute infectious diseases.

Abscess-forming neutrophilic dermatosis: report of three cases associated with hemopathies

BACKGROUND

The development of different types of neutrophilic dermatosis is reported to occur in the course of malignant hemopathies. These concern mainly Sweet's syndrome, pyoderma gangrenosum, erythema elevatum et diutinum and neutrophilic eccrine hidradenitis.

OBSERVATIONS

We have recently encountered the cases of 3 patients who presented all with multiple acneiform papules and dome-shaped aseptic abscesses leaving scars. Pus was sterile in all except case 3 in which slight Staphylococcus aureus growth was shown. However, in this patient, only steroids were effective demonstrating that this bacterium was not responsible for the disease. Histopathology disclosed a dense dermal polymorphonuclear neutrophil infiltrate and some mononuclear cells. Two of these patients had myelodysplastic syndromes while one had IgA myeloma.

CONCLUSION

Abscess-forming neutrophilic dermatosis seems to be another type of neutrophilic dermatosis associated with hematological malignancies.

[Immunological parallels in the use of ultraviolet irradiation of autoblood in patients with suppurative diseases of soft tissue]

Ultraviolet irradiation of autoblood in patients with suppurative diseases of soft tissues increased the titer of specific antibacterial antibodies and the number of antibody-producing cells (APC), which was the most expressed in cases when the erythrocytes and leukocytes were exposed separately. Study of the count of APC during UV exposure showed it to increase 6-8 h after the procedure.

[The clinical significance of membrane-destructive processes and their correction in children with suppurative surgical infection]

The results of examination of 101 patients with purulent surgical infection provide evidence of considerable disorders of cell membrane metabolism which correspond to the severity of the disease. Three states of the antioxidant defence system were distinguished: compensated, subcompensated, and decompensated. It is suggested that antioxidant and membrane-stimulating treatment should be applied with consideration for the types of the course followed by the metabolic processes (metabolically latent, lipoperoxidatative, and peroxidative). The clinical effect of the use of antioxidants in 38 patients is shown.

[Sulfhydryl groups and succinate dehydrogenase of blood lymphocytes in patients with inflammatory processes]

Patients with pyo-inflammatory processes were found to have a reduced SH-group content and SDH activity of peripheral blood lymphocytes. A clear dependence between the severity and extent of the pyo-inflammatory process and the SH-group and SDH values. Lymphocyte SDH is more sensitive than the SH-groups to the pyo-inflammatory process and responds by reduced activity. Study of SDH activity and SH-group content of lymphocytes in dynamics are sensitive tests for the severity of the pyo-inflammatory process, unspecific reactivity of the organism, and the efficacy of the applied treatment.

Characterization of a soft-tissue infection model in the horse and its response to intravenous cephapirin administration

A soft-tissue infection model was created in eight horses by infecting subcutaneous tissue chambers with Streptococcus zooepidemicus organisms. Responses of the horses to the infections were determined by monitoring changes in the complete blood count and body temperature and by following changes in the cytology and protein content of the tissue chambers. Systemic reactions to the infections included a mild neutrophilia, mild pyrexia and mild anemia. There was a marked influx of neutrophils and protein into the chambers after they were seeded with bacteria and chamber neutrophil viability decreased markedly at the height of the infection. Subsequent to establishing tissue chamber infections four of the horses were treated with intravenous cephapirin t.d. at a dosage of 20 mg/kg for 5 days. Quantitative culturing of tissue chamber fluid was performed to analyze the efficacy of cephapirin therapy. Cephapirin therapy was accompanied by decreases in the systemic neutrophilia, pyrexia, anemia, and chamber bacterial counts. However, cephapirin did not eliminate the infection in any of the chambers. Chamber neutrophil viability was markedly increased during the cephapirin therapy period.

[Myeloperoxidase deficiency as a cause of recurrent infections]

Myeloperoxidase (MPO) deficiency is a common hereditary leukocyte function defect. A two year old girl with MPO-deficiency suffered from recurrent skin infections. No MPO-activity was detectable in leukocytes of her peripheral blood smears, while NBT reduction and chemotactic activity was normal. The quantitative enzyme determination in leukocyte sonicates confirmed the total MPO-deficiency in the girl's leukocytes and a partial MPO-deficiency in the cells of her mother. The patient leukocytes demonstrated also an impaired chemiluminescence.

[Determination of pathogens in blood in disseminated gonococcal infection. Case report and overview of the literature]

Although Neisseria gonorrhoeae has been recognized as causative agent of infectious disease not only of the genital region but also of other organs already at the end of the 19th century, disseminated gonococcal infection as a clinical entity has been defined fairly recently, i.e., during the last decade. In particular, it has been very difficult for a long time to detect Neisseria gonorrhoeae in the blood of patients suffering from this form of gonorrhea. Therefore, the case of a 22-year-old woman is presented who developed fever, arthritis, and pustules and from whose cervix, rectum, and blood Neisseria gonorrhoeae could be grown. Based on the reports in the literature and our own experience indispensable and further desirable diagnostic measures to be adopted in such cases are discussed.

An immunoglobulin (IgG) inhibitor of polymorphonuclear leukocyte motility in a patient with recurrent infection

We isolated from the serum of a patient with recurrent skin infections an IgG immunoglobulin that irreversibly inhibits the random motility and chemotactic responsiveness of polymorphonuclear leukocytes. Although the patient's leukocytes behaved like normal cells with respect to adherence, phagocytosis, degranulation, and generation of the superoxide anion, they did not migrate normally toward standard chemotactic stimuli. Normal human polymorphonuclear leukocytes behaved similarly after incubation with the patient's serum. Inhibition of motility was not associated with cyutotoxicity. Inhibitory activity could be removed completely from the patient's serum by treatment with either agarose-bound anti-human IgG or Sepharose-bound staphylococcal protein A. Exposure of normal polymorphonuclear leukocytes to as little as 1.25 microgram per milliliter (0.00125 g per liter) of the patient's purified IgG caused significant inhibition of random motility and chemotactic responsiveness (P < 0.01). Thus, IgG immunoglobulins can inhibit leukocyte motility specifically and irreversibly, and thereby adversely affect host defenses against invading microorganisms.

A familial defect of neutrophil chemotaxis with asthma, eczema, and recurrent skin infections

A defect in chemotaxis of peripheral blood polymorphonuclear leukocytes (PMN's) was demonstrated in both parents and three of four children in a single family afflicted with varying degrees of respiratory allergy, unusual onset of severe eczema in the first month of life, and recurrent bacterial skin infections. Of great interest was the identification of HLA-B12 at the B locus in all affected members but not in the unaffected child. The two children known since infancy to be most severely affected with eczema and recurrent infections are HLA identical and homozygous for HLA-B12. The child without eczema and infections had an intermediate cellular chemotactic defect most apparent on kinetic studies.

Experimental infection of the skin in the hamster simulating human impetigo. IV. Cellular responses after streptococcal and staphylococcal infections

Various cellular responses to skin infections in an experimental animal model were explored. Total leukocyte counts varied after group A streptococcal infections, but a depression was commonly seen after M type 12 impetigo. Staphylococcus aureus infections resulted in moderate leukocytosis. A marked neutrophilia was universal with streptococcal or staphylococcal disease. A positive nitroblue tetrazolium (NBT) response appeared 24 hr after infection, reached a peak in 48 hr, and then declined. This occurred in the absence of extensive cellulitis or bacteremia. An increase in the percentage and absolute number of NBT-positive neutrophils occurred. M type 57 streptococcus produced a more strongly positive NBT test than did M type 12. Cell-free filtrates of a broth culture of M type 57 streptococcus produced NBT responses in hamsters comparable to the responses seen after injection of live organisms. These studies indicate the usefulness of this animal model to study various parameters of the NBT test.