Treatment option for sepsis in children in the era of antibiotic resistance

Antibiotic Resistance Mechanisms and Their Transmission in Acinetobacter baumannii

The discovery of penicillin over 90 years ago and its subsequent uptake by healthcare systems around the world revolutionised global health. It marked the beginning of a golden age in antibiotic discovery with new antibiotics readily discovered from natural sources and refined into therapies that saved millions of lives. Towards the end of the last century, the rate of discovery slowed to a near standstill. The lack of discovery is compounded by the rapid emergence and spread of bacterial pathogens that exhibit resistance to multiple antibiotic therapies and threaten the sustainability of global healthcare systems. Acinetobacter baumannii is an opportunistic pathogen whose prevalence and impact has grown significantly over the last 20 years. It is recognised as a barometer of the antibiotic resistance crisis due to the diverse array of mechanisms by which it can become resistant.

Intravenous colistin use for infections due to MDR Gram-negative bacilli in critically ill paediatric patients: a systematic review and meta-analysis

BACKGROUND

Data are limited regarding the clinical effectiveness and safety of intravenous colistin for treatment of infections due to MDR Gram-negative bacilli (GNB) in paediatric ICUs (PICUs).

METHODS

Systematic review of intravenous colistin use in critically ill paediatric patients with MDR-GNB infection in PubMed, Scopus and EMBASE (up to 31 January 2018).

RESULTS

Out of 1181 citations, 7 studies were included on the use of intravenous colistin for 405 patients in PICUs. The majority of patients were diagnosed with lower respiratory tract infections, Acinetobacter baumannii being the predominant pathogen. Colistin dosages ranged between 2.6 and 18 mg/kg/day, with only one case reporting a loading dose. Emergence of colistin resistance during treatment was reported in two cases. Nephrotoxicity and neurotoxicity were reported in 6.1% and 0.5%, respectively, but concomitant medications and severe underlying illness limited our ability to definitively associate use of colistin with nephrotoxicity. Crude mortality was 29.5% (95% CI = 21.7%-38.1%), whereas infection-related mortality was 16.6% (95% CI = 12.2%-21.5%).

CONCLUSIONS

While the reported incidence of adverse events related to colistin was low, reported mortality rates for infections due to MDR-GNB in PICUs were notable. In addition to severity of disease and comorbidities, inadequate daily dosage and the absence of a loading dose may have contributed to mortality. As the use of colistin for treatment of MDR-GNB infections increases, it is imperative to understand whether optimal dosing of colistin in paediatric patients differs across different age groups. Thus, future studies to establish the pharmacokinetic properties of colistin in different paediatric settings are warranted.

Tigecycline Therapy for Multi-drug-Resistant Pseudomonas aeruginosa Sepsis Associated with Multi-organ Failure in an Infant with Persistent Arterial Duct. Case Report

Sepsis is the leading cause of death in infants and children worldwide. The growing drug resistance in nosocomial gram-negative bacteria has resulted in treatment challenges. One of the most common multi-drug-resistant bacteria is Pseudomonas aeruginosa. Resistance to antibiotics used in Pseudomonas aeruginosa infections limits the therapeutic options. We present a tigecycline administration in a 5-month-old infant with patent arterial duct, heart failure, and respiratory failure due to respiratory syncytial virus bronchiolitis with subsequent respiratory distress syndrome and severe sepsis caused by multi-drug-resistant Pseudomonas aeruginosa. Despite combined antibiotic therapy with meropenem, amikacin, and colistin, inflammatory markers increased. Because of life-threatening condition, tigecycline was added to the therapy and was administered intravenously twice daily. Within 48 h, inflammatory markers started to decrease and tigecycline therapy continued for 13 days without adverse effects. Tigecycline used in combination with other antibiotics might be a valuable therapeutic approach in the management of multi-drug-resistant bacteria infections in pediatric patients when conventional antibiotics have failed. Further studies are needed to evaluate the efficacy and safety of tigecycline administration in critically ill pediatric patients.

Engineered Cationic Antimicrobial Peptides (eCAPs) to Combat Multidrug-Resistant Bacteria

The increasing rate of antibiotic resistance constitutes a global health crisis. Antimicrobial peptides (AMPs) have the property to selectively kill bacteria regardless of resistance to traditional antibiotics. However, several challenges (e.g., reduced activity in the presence of serum and lack of efficacy in vivo) to clinical development need to be overcome. In the last two decades, we have addressed many of those challenges by engineering cationic AMPs de novo for optimization under test conditions that typically inhibit the activities of natural AMPs, including systemic efficacy. We reviewed some of the most promising data of the last two decades in the context of the advancement of the field of helical AMPs toward clinical development.

Fosfomycin in the pediatric setting: Evidence and potential indications

To date, there has been little experience in using fosfomycin in children. However, its broad spectrum of action and excellent safety profile have renewed interest in this antibiotic, especially for treating infections by multidrug-resistant bacteria. The main indication for fosfomycin in pediatrics is currently community-acquired lower urinary tract infection. Given its good activity against bacteria, fosfomycin can also be useful in urinary infections caused by extended-spectrum beta-lactamase-producing enterobacteria. Fosfomycin presents very good dissemination to tissues including bone and is therefore an option in the combined therapy of osteomyelitis, especially in cases produced by methicillin-resistant Staphylococcus aureus (MRSA) or in cases with beta-lactam allergies. Fosfomycin can also be employed in combination for multidrug-resistant Gram-negative bacteremia (especially carbapenemase-producing enterobacteria), S. aureus (if there is a high suspicion of MRSA or complicated infections) and vancomycin-resistant Enterococcus spp. Other infections in which fosfomycin could be part of a combined therapy include staphylococcal endocarditis (in case of beta-lactam allergy or MRSA), central nervous system infections (mainly by MRSA, S. epidermidis, Listeria and resistant pneumococcus), nosocomial pneumonia and infections associated with mechanical ventilation.

Tigecycline salvage therapy for critically ill children with multidrug-resistant/extensively drug-resistant infections after surgery

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of salvage therapy of tigecycline in critically ill children with infections caused by multidrug-resistant (MDR)/extensively drug-resistant (XDR) bacteria after surgery.

METHODS

A retrospective chart review was performed of critically ill children after surgery who had received tigecycline for ≥3days between June 2012 and May 2016 in the surgical intensive care unit of a tertiary level children's hospital.

RESULTS

Of 6442 consecutive children admitted after surgery, a total of 22 were enrolled. They had a median age of 7.5 months (interquartile range (IQR), 6 months to 4 years) and a median weight of 7.3kg (IQR, 5.1-12.5kg). Patients received tigecycline for a median 17days (IQR, 12-20 days). The median intensive care unit stay was 56days (IQR, 38-61 days) and median hospital stay was 78days (IQR, 61-94 days). Tigecycline was prescribed as culture-directed therapy in 91% of patients and as empirical therapy in 9%. Clinical success was reported in 86% of the patients. The all-cause mortality in this cohort was 18%. No serious adverse effects of tigecycline were detected in these patients.

CONCLUSIONS

Tigecycline salvage therapy was successful in 86% of critically ill pediatric patients with MDR/XDR infections after surgery, with no severe adverse effects.

Optimal infusion rate in antimicrobial therapy explosion of evidence in the last five years

Background

Sporadic studies in antimicrobial therapy have evaluated the effects of infusion rates on therapeutic and economic outcomes, and new findings may challenge the regular infusion regimen.

Methods

Focusing on studies comparing the outcomes of different infusion regimens, the relevant literature was identified by searching PubMed, Web of Science, and Scopus from January 1, 2013 to March 1, 2018. Papers were finally chosen using a PRISMA flowchart.

Results

Antimicrobials with the superiority of prolonged infusion to standard infusion in terms of efficacy and safety include meropenem, doripenem, imipenem, cefepime, ceftazidime, piperacillin/tazobactam, linezolid, and vancomycin. The strategy of concomitantly reducing total daily dose and prolonging infusion time may cause treatment failure (eg, imipenem). Extended infusion of piperacillin/tazobactam has pharmacoeconomic advantage over standard infusion. Prolonged infusion of voriconazole is inferior to standard infusion because of lower efficacy caused by pharmacokinetic changes. Comparable outcomes following standard infusion and continuous infusion were observed with norvancomycin and nafcillin. Factors determining whether prolonged infusion has a benefit over standard infusion include MIC of bacterial pathogens, bacterial density, diagnosis, disease severity, total daily dose, and renal function.

Conclusion

To maximally preserve the effectiveness of current antimicrobials, effective interventions should be implemented to enhance the application of optimal infusion strategies. For reducing nephrotoxicity, prolonged infusion of meropenem is better than conventional infusion in neonates with Gram-negative late-onset sepsis, and continuous infusion of vancomycin is superior to intermittent infusion. For increasing efficacy, prolonged or continuous infusion of time-dependent antimicrobials (eg, meropenem, doripenem, imipenem, cefepime, ceftazidime, piperacillin/tazobactam, linezolid, and vancomycin) is an optimal choice. Nevertheless, such advantages may only be demonstrated in special clinical circumstances and special populations (eg, patients with a sequential organ failure assessment (SOFA) score≥9, respiratory tract infections, urinary or intra-abdominal infections, or infections caused by less susceptible pathogens would benefit from prolonged infusion of piperacillin/tazobactam).

Antibiotic resistance of pathogenic Acinetobacter species and emerging combination therapy

The increasing antibiotic resistance of Acinetobacter species in both natural and hospital environments has become a serious problem worldwide in recent decades. Because of both intrinsic and acquired antimicrobial resistance (AMR) against last-resort antibiotics such as carbapenems, novel therapeutics are urgently required to treat Acinetobacter-associated infectious diseases. Among the many pathogenic Acinetobacter species, A. baumannii has been reported to be resistant to all classes of antibiotics and contains many AMR genes, such as bla _ADC (Acinetobacter-derived cephalosporinase). The AMR of pathogenic Acinetobacter species is the result of several different mechanisms, including active efflux pumps, mutations in antibiotic targets, antibiotic modification, and low antibiotic membrane permeability. To overcome the limitations of existing drugs, combination theraphy that can increase the activity of antibiotics should be considered in the treatment of Acinetobacter infections. Understanding the molecular mechanisms behind Acinetobacter AMR resistance will provide vital information for drug development and therapeutic strategies using combination treatment. Here, we summarize the classic mechanisms of Acinetobacter AMR, along with newly-discovered genetic AMR factors and currently available antimicrobial adjuvants that can enhance drug efficacy in the treatment of A. baumannii infections.

Retrospective analysis of tigecycline shows that it may be an option for children with severe infections

AIM

This study assessed the efficacy and safety of tigecycline in children with life-threatening infections.

METHODS

We retrospectively reviewed the clinical records of patients treated with tigecycline from June 2012 to May 2014 in a Chinese tertiary centre.

RESULTS

The study comprised 24 patients (14 male) with a median age of four years (range, 50 days-12 years). The most frequently isolated microorganism, most common isolation site and type of infection were Acinetobacter baumannii, tracheal aspirate fluid and ventilator-associated pneumonia, respectively. Tigecycline was administered at a loading dose of 1.5 or 2.0 mg/kg and 1.0 mg/kg every 12 hours after that. The average duration of treatment was 11.6 ± 5.8 days. The clinical response and microbiological eradication rate were 37.5% and 29.2%, respectively. Six of the patients we studied (25.0%) died, and three of these deaths were considered to be infection related. Adverse drug reactions were identified in four patients (16.7%) during the treatment, including abnormal liver function, prolonged prothrombin time and diarrhoea.

CONCLUSION

Our findings suggest that tigecycline may be an option for children with severe infections. However, more prospective, controlled trials are required to objectively evaluate the efficacy and safety of tigecycline in children.

[Antibiotic consumption and bacterial sensitivity in a teaching hospital: A 5-year study]

INTRODUCTION

To reduce risks of antibiotic resistance, governmental and learned societies decreed the optimal use of antibiotics. The relation between antibiotic consumption and bacterial resistance increase has been clearly demonstrated over the last several years. Antibiotic consumption data and bacterial sensitivity data are regularly published, but very few publications have searched for a correlation between these two variables. This study focused on antibiotic use and consumption as well as bacterial sensitivity to these antibiotics.

OBJECTIVES

The main objective was to describe the changes in antibiotic consumption and bacterial sensitivity in a mother-child teaching hospital. The secondary objectives were to explore whether antibiotic use and bacterial sensitivity were correlated and to comment on the usefulness of these data for clinicians.

METHODS

This was a 5-year retrospective, descriptive, cross-sectional study. All samples from usually sterile biologic liquids of hospitalized pediatric patients were included in the study. The samples from outpatient clinics were excluded. All types of bacteria identified in more than 30 isolates were included in the study. The antibiotics usually used to treat these bacteria were included. To assess antibiotic consumption, we calculated the number of days of therapy per 1000 patient-days for hospitalized pediatric patients and we calculated the Pearson correlation coefficient between antibiotic consumption and sensitivity rates to these antibiotics. Two scenarios were explored: one with correlation by year and one with the next year for bacterial sensitivity.

RESULTS

During the study period (2010-2011 to 2014-2015), overall antibiotics consumption remained relatively stable. Concerning bacterial sensitivity, we noted important changes (sensitivity rates increased for 12 antibiotic-bacteria pairs, remained stable for five, and decreased for 15). We found three significant correlations for the first scenario: Pseudomonas aeruginos-ceftazidime (P=0.01), P. aeruginosa-ciprofloxacin and fluoroquinolone consumption (P=0.02), Enterococcus sp-ampicillin and penicillin consumption (P=0.04). For the second scenario, we found only two significant correlations: coagulase-negative Staphylococcus-oxacilline and penicillin consumption (P=0.02), P. aeruginosa/piperacillin (P=0.04).

CONCLUSION

This exploratory study allowed us to describe antibiotic consumption and bacterial sensitivity progression. To our knowledge, this is the first study exploring the correlation between antibiotic consumption and the bacterial sensitivity rate in pediatrics in Canada. It remains very difficult to show this correlation between these two variables because of the multiple sources of bacterial resistance. These data are particularly useful for the antimicrobial stewardship programs and for clinicians.