Pharmacokinetics of Antimicrobials in Children with Emphasis on Challenges Faced by Low and Middle Income Countries, a Clinical Review

Infectious complications in the pediatric immunocompromised host: a narrative review

BACKGROUND

Infections are a major cause for morbidity in children with primary or secondary immunodeficiency, and have a negative impact on overall outcome.

OBJECTIVES

This narrative review presents select pediatric specific aspects regarding the clinical impact, diagnosis, management and follow-up of infectious complications in patients with primary and secondary immunodeficiencies.

SOURCES

PubMed until January 2024 and searched references in identified articles including the search terms: infection, immunodeficiency or cancer, diagnostics, antimicrobial agents, bacteria or fungus or virus, and follow-up.

CONTENT

Major advances have been made in the early detection and management of patients with primary immunodeficiency, and multiple analyses report in children with cancer on risk groups and periods of risk for infectious complications. Although many diagnostic tools are comparable between children and adults, specific considerations have to be applied, such as minimizing the use of radiation. Antimicrobial drug development remains a major challenge in the pediatric setting, which includes the establishment of appropriate dosing and pediatric approval. Last, long-term follow-up and the impact of late effects are extremely important to be considered in the management of immunocompromised pediatric patients.

IMPLICATIONS

Although infectious disease supportive care of immunocompromised children and adolescents has considerably improved over the last three decades, close international collaboration is needed to target the specific challenges in this special population.

Challenges of Antibiotic Formulations and Administration in the Treatment of Bloodstream Infections in Children Under Five Admitted to Kisantu Hospital, Democratic Republic of Congo

Severe bacterial infections in children need prompt, appropriate antibiotic treatment. We report challenges observed within a prospective, cohort study on antibiotic efficacy in non-typhi Salmonella bloodstream infection (NCT04850677) in Kisantu district hospital (Democratic Republic of Congo). Children (aged > 28 days to < 5 years) admitted with suspected bloodstream infection (August 1, 2021 through July 31, 2022) were enrolled and followed until day 3 or discharge for non-typhi Salmonella patients. Antibiotics were administered to 98.4% (1,838/1,867) of children, accounting for 2,296 antibiotic regimens (95.7% intravenous, 4.3% oral). Only 78.3% and 61.8% of children were, respectively, prescribed and administered antibiotics on the admission day. At least one dose was not administered in 3.6% of children, mostly because of mismatch of the four times daily cefotaxime schedule with the twice-daily administration rounds. Inappropriate intravenous administration practices included multidose use, air-venting, and direct injection instead of perfusion. There was inaccurate aliquoting in 18.0% (32/178) of intravenous ciprofloxacin regimens, and thus administered doses were > 16% below the intended dose. Dosing accuracy of oral suspensions was impaired by lack of instructions for reconstitution, volume indicators, and/or dosing devices. Adult-dose tablets were split without/beyond scoring lines in 84.4% (27/32) of tablets. Poor availability and affordability of age-appropriate oral formulations contributed to low proportions of intravenous-to-oral switch (33.3% (79/237) of non-typhi Salmonella patients). Other quality issues included poor packaging, nonhomogeneous suspensions, and unsafe water for reconstitution. In conclusion, poor antibiotic products (no age-appropriate formulations, poor quality and access), processes (delayed prescription/administration, missed doses), and practices (inaccurate doses, [bio]safety risks) must be urgently addressed to improve pediatric antibiotic treatment.

Activity of Cinnamic Acid Derivatives with 4-Chloro-2-mercaptobenzenesulfonamide Moiety against Clinical HLAR and VRE Enterococcus spp

The rapid increase in strains that are resistant to antibiotics requires new active compounds to be found whose mechanism of action on bacteria is different to those that are currently known. Of particular interest are compounds that occur in plants as secondary metabolites. The focus of this study concerns the examination of the effects of synthetic cinnamic acid derivatives, with 4-chloro-2-mercaptobenzenesulfonamide moiety on Enterococcus spp. with HLAR (high-level aminoglycoside resistance) and VRE (vancomycin-resistant Enterococcus) mechanisms. The minimum inhibitory concentration (MIC) values of the tested compounds were determined using the serial dilution method for Enterococcus spp. groups, and the most active compounds were as follows: 16d, 17c, 16a, 16c and 16f (2-4 µg/mL). These compounds, at a concentration of 4 × MIC, inhibited the biofilm formation of HLAR strains (70 to 94%). At concentrations of 2 × MIC and 4 × MIC, they also inhibited the growth of VRE strains (42 to 96%). The best effect produced on the formed biofilm was demonstrated by compound 16f (from 62% MIC concentration to 89% 4 × MIC concentration) on the tested HLAR strains. In vitro studies, using the peripheral blood of domestic sheep, demonstrated the stable bacteriostatic activity of the tested compounds against Enterococcus spp. The compounds 16a, 16c, 16d, 16f and 17c showed synergism and additivity with ampicillin, streptomycin, gentamicin and vancomycin against resistant strains of Enterococcus spp. The tested compounds, when combined, reduce the MIC for antibiotics by 800 to 10,000 times for HLAR strains and by 8 to 10,000 times for VRE strains. The MIC of the tested compounds, in combination with antibiotics, is reduced 2-16-fold for HLAR strains and 2-32-fold for VRE strains. These studies demonstrate the potential for the therapeutic use of synthetic, cinnamic acid derivatives, with 4-chloro-2-mercaptobenzenesulfonamide moiety, to work against clinical strains of Enterococcus spp.

Antimicrobial and Cytotoxic Activities of Water-Soluble Isoxazole-Linked 1,3,4-Oxadiazole with Delocalized Charge: In Vitro and In Vivo Results

The distinct structure of cationic organic compounds plays a pivotal role in enhancing their water solubility, which in turn influences their bioavailability. A representative of these compounds, which contains a delocalized charge, is 5-amino-2-(5-amino-3-methyl-1,2-oxazol-4-yl)-3-methyl-2,3-dihydro-1,3,4-oxadiazol-2-ylium bromide (ED). The high-water solubility of ED obviates the need for potentially harmful solvents during in vitro testing. The antibacterial and antifungal activities of the ED compound were assessed in vitro using the microtiter plate method and a biocellulose-based biofilm model. Additionally, its cytotoxic effects on wound bed fibroblasts and keratinocytes were examined. The antistaphylococcal activity of ED was also evaluated using an in vivo larvae model of Galleria mellonella. Results indicated that ED was more effective against Gram-positive bacteria than Gram-negative ones, exhibiting bactericidal properties. Furthermore, ED demonstrated greater efficacy against biofilms formed by Gram-positive bacteria. At bactericidal concentrations, ED was non-cytotoxic to fibroblasts and keratinocytes. In in vivo tests, ED was non-toxic to the larvae. When co-injected with a high load of S. aureus, it reduced the average larval mortality by approximately 40%. These findings suggest that ED holds promise for further evaluation as a potential treatment for biofilm-based wound infections, especially those caused by Gram-positive pathogens like S. aureus.

Developmental Pharmacokinetics of Antibiotics Used in Neonatal ICU: Focus on Preterm Infants

Neonatal Infections are among the most common reasons for admission to the intensive care unit. Neonatal sepsis (NS) significantly contributes to mortality rates. Empiric antibiotic therapy of NS recommended by current international guidelines includes benzylpenicillin, ampicillin/amoxicillin, and aminoglycosides (gentamicin). The rise of antibacterial resistance precipitates the growth of the use of antibiotics of the Watch (second, third, and fourth generations of cephalosporines, carbapenems, macrolides, glycopeptides, rifamycins, fluoroquinolones) and Reserve groups (fifth generation of cephalosporines, oxazolidinones, lipoglycopeptides, fosfomycin), which are associated with a less clinical experience and higher risks of toxic reactions. A proper dosing regimen is essential for effective and safe antibiotic therapy, but its choice in neonates is complicated with high variability in the maturation of organ systems affecting drug absorption, distribution, metabolism, and excretion. Changes in antibiotic pharmacokinetic parameters result in altered efficacy and safety. Population pharmacokinetics can help to prognosis outcomes of antibiotic therapy, but it should be considered that the neonatal population is heterogeneous, and this heterogeneity is mainly determined by gestational and postnatal age. Preterm neonates are common in clinical practice, and due to the different physiology compared to the full terms, constitute a specific neonatal subpopulation. The objective of this review is to summarize the evidence about the developmental changes (specific for preterm and full-term infants, separately) of pharmacokinetic parameters of antibiotics used in neonatal intensive care units.