Is colistin effective in the treatment of infections caused by multidrug-resistant (MDR) or extremely drug-resistant (XDR) gram-negative microorganisms in children?

Is the high dose extended infusion of meropenem useful in the treatment of highly resistant gram-negative bacteria in children?

OBJECTIVES

Multidrug resistant infections present a treatment challenge for clinicians. These infections have been associated with increased morbidity and mortality. Recently, there has been increasing discussion in the literature that high dose extended infusion of meropenem may be helpful. We aimed to evaluate the clinical efficacy of high dose extended infusion of meropenem in the treatment of highly resistant Gram-negative infections.

METHODS

This retrospective observational study was conducted between December 2014 and December 2020 at Hacettepe University Ihsan Dogramaci Children's Hospital. Clinical and microbiological data of children diagnosed with invasive multidrug and extremely drug resistant Gram-negative infections were studied. The findings of patients given high dose extended infusion of meropenem were compared with patients who received colistin or tigecycline.

RESULTS

Overall, 158 pediatric patients infected with multidrug and extremely drug resistant gram-negatives were enrolled; 76 treated with high-dose prolonged infusion of meropenem; 60 treated with colistin and 22 with tigecycline. The overall clinical response at the end of the treatment was 81.6 % in meropenem group, 83.3 % in colistin group and 77.3 % in tigecycline group (P = 0.821). Microbiological response at the end of the treatment was 81.1 % in meropenem group, 76.4 % in colistin group and 72.2 % in tigecycline group (P = 0.694).

CONCLUSION

Meropenem, with an adjusted dose (high-dose and extended), seems a crucial and robust fighting agent in the treatment of pediatric patients infected with highly-resistant Gram-negative bacteria. It may also be useful in preventing the use of the latest fighting tools such as colistin and tigecycline during the antibacterial stewardship process.

Incidence of Antimicrobial-Associated Acute Kidney Injury in Children: A Structured Review

Acute kidney injury (AKI) is a commonly reported adverse effect of administration of antimicrobials. While AKI can be associated with poorer outcomes, there is little information available to understand rates of AKI in children exposed to various antimicrobials. We performed a structured review using the PubMed and Embase databases. Articles were included if they provided an AKI definition in patients who were < 19 years of age receiving an antimicrobial and reported the frequency of AKI. Author-defined AKI rates were calculated for each study and mean pooled estimates for each antimicrobial were derived from among all study participants. Pooled estimates were also derived for those studies that reported AKI according to pRIFLE (pediatric risk, injury, failure, loss, end stage criteria), AKIN (acute kidney injury network), or KDIGO (kidney disease improving global outcomes) creatinine criteria. A total of 122 studies evaluating 28 antimicrobials met the inclusion criteria. Vancomycin was the most commonly studied drug: 11,514 courses across 44 included studies. Among the 27,285 antimicrobial exposures, the overall AKI rate was 13.2% (range 0-42.1% by drug), but the rate of AKI varied widely across studies (range 0-68.8%). Cidofovir (42.1%) and conventional amphotericin B (37.0%) had the highest pooled rates of author-defined AKI. Eighty-one studies used pRIFLE, AKIN, or KDIGO AKI criteria and the pooled rates of AKI were similar to author-defined AKI rates. In conclusion, antimicrobial-associated AKI is reported to occur frequently in children, but the rates of AKI varies widely across studies and drugs. Most published studies examined hospitalized patients and heterogeneity in study populations and in author definitions of AKI are barriers to a comparison of nephrotoxicity risk among antimicrobials in children.

No increased acute kidney injury rate through giving an intravenous colistin loading dose in pediatric patients

OBJECTIVES

A colistin loading dose is required to achieve adequate drug exposure for the treatment of multidrug-resistant Gram-negative bacteria. However, data on acute kidney injury (AKI) rates associated with this approach in children have been unavailable. The aim of this study was to examine AKI rates in children who were prescribed a colistin loading dose.

METHODS

A retrospective study was conducted in patients aged 1 month to 18 years who had received intravenous colistin for ≥48 h. Loading dose (LD) was defined as colistin methanesulfonate at 4-5 mg of colistin base activity/kg/dose. AKI was defined according to KDIGO serum creatinine (SCr) criteria - SCr ≥ 1.5 times the baseline, measured 3-7 days after colistin initiation. Augmented renal clearance (ARC) was defined as an estimated glomerular filtration rate (eGFR) >150 mL/min/1.73 m². The rates of AKI were compared between children receiving or not receiving an LD, and between different eGFR groups.

RESULTS

In total, 181 children were enrolled. The mean age was 4.3 years (95% confidence interval [CI], 3.6-4.9 years). Ninety-five of the subjects (52.5%) were male. There were 157 children with a baseline eGFR of ≥ 80 mL/min/1.73 m². The overall AKI rate within the first week in this group was 20.4% (95% CI, 14.4-27.6%): LD, 16.1% vs no LD, 23.2% (p = 0.29). Subgroup analysis, excluding patients with ARC, showed a lower AKI rate of 12.8% (95% CI, 6.8-21.3%): LD, 9.7% vs no LD, 14.3% (p = 0.53).

CONCLUSIONS

AKI rate was not different among children who received an intravenous colistin loading dose. This approach should be implemented to ensure the necessary drug exposure required for good treatment outcomes.

Systematic review on estimated rates of nephrotoxicity and neurotoxicity in patients treated with polymyxins

BACKGROUND

Nephrotoxicity and neurotoxicity are commonly associated with polymyxin treatment; however, the emergence of multidrug-resistant Gram-negative bacteria with limited therapeutic options has resulted in increased use of polymyxins.

OBJECTIVES

To determine the rates of nephrotoxicity and neurotoxicity during polymyxin treatment and whether any factors influence these.

DATA SOURCES

Medline, Embase and Cochrane Library databases were searched on 2 January 2020.

STUDY ELIGIBILITY CRITERIA

Studies reporting nephrotoxicity and/or neurotoxicity rates in patients with infections treated with polymyxins were included. Reviews, meta-analyses and reports not in English were excluded.

PARTICIPANTS

Patients hospitalized with infections treated with systemic or inhaled polymyxins were included. For comparative analyses, patients treated with non-polymyxin-based regimens were also included.

METHODS

Meta-analyses were performed using a random-effects model; subgroup meta-analyses were conducted where data permitted using a mixed-effects model.

RESULTS

In total, 237 reports of randomized controlled trials, cohort and case-control studies were eligible for inclusion; most were single-arm observational studies. Nephrotoxic events in 35,569 patients receiving polymyxins were analysed. Overall nephrotoxicity rate was 0.282 (95% confidence interval (CI) 0.259-0.307). When excluding studies where >50% of patients received inhaled-only polymyxin treatment or nephrotoxicity assessment was by methods other than internationally recognized criteria (RIFLE, KDIGO or AKIN), the nephrotoxicity rate was 0.391 (95% CI 0.364-0.419). The odds of nephrotoxicity were greater with polymyxin therapies compared to non-polymyxin-based regimens (odds ratio 2.23 (95% CI 1.58-3.15); p < 0.001). Meta-analyses showed a significant effect of polymyxin type, dose, patient age, number of concomitant nephrotoxins and use of diuretics, glycopeptides or vasopressors on the rate of nephrotoxicity. Polymyxin therapies were not associated with a significantly different rate of neurotoxicity than non-polymyxin-based regimens (p 0.051). The overall rate of neurotoxicity during polymyxin therapy was 0.030 (95% CI 0.020-0.043).

CONCLUSIONS

Polymyxins are associated with a higher risk of nephrotoxicity than non-polymyxin-based regimens.

Propranolol, chlorpromazine and diclofenac restore susceptibility of extensively drug-resistant (XDR)-Acinetobacter baumannii to fluoroquinolones

Nosocomial infections caused by extensively drug-resistant (XDR) or Pan-Drug resistant (PDR) Acinetobacter (A.) baumannii have recently increased dramatically creating a medical challenge as therapeutic options became very limited. The aim of our study was to investigate the antibiotic-resistance profiles and evaluate the various combinations of ciprofloxacin (CIP) or levofloxacin (LEV) with antimicrobial agents and non-antimicrobial agents to combat antimicrobial resistance of XDR A. baumannii. A total of 100 (6.25%) A. baumannii clinical isolates were recovered from 1600 clinical specimens collected from hospitalized patients of two major university hospitals in Upper Egypt. Antimicrobial susceptibility tests were carried out according to CLSI guidelines. Antimicrobial susceptibility testing of the respective isolates showed a high percentage of bacterial resistance to 19 antimicrobial agents ranging from 76 to99%. However, a lower percentage of resistance was observed for only colistin (5%) and doxycycline (57%). The isolates were categorized as PDR (2; 2%), XDR (68; 68%), and multi-drug resistant (MDR) (30; 30%). Genotypic analysis using ERIC-PCR on 2 PDR and 32 selected XDR isolates showed that they were not clonal. Combinations of CIP or LEV with antibiotics (including, ampicillin, ceftriaxone, amikacin, or doxycycline) were tested on these A. baumannii non-clonal isolates using standard protocols where fractional inhibitory concentrations (-FICs) were calculated. Results of the respective combinations showed synergism in 23.5%, 17.65%, 32.35%, 17.65% and 26.47%, 8.28%, 14.71%, 26.47%, of the tested isolates, respectively. CIP or LEV combinations with either chlorpromazine (CPZ) 200 μg/ml, propranolol (PR) in two concentrations, 0.5 mg/ml and 1.0 mg/ml or diclofenac (DIC) 4 mg/ml were carried out and the MIC decrease factor (MDF) of each isolate was calculated and results showed synergism in 44%, 50%, 100%, 100% and 94%, 85%, 100%, 100%, of the tested isolates, respectively. In conclusion, combinations of CIP or LEV with CPZ, PR, or DIC showed synergism in most of the selected PDR and XDR A. baumannii clinical isolates. However, these combinations have to be re-evaluated in vivo using appropriate animal models infected by XDR- or PDR- A. baumannii.

Population Pharmacokinetics of Intravenous Colistin in Pediatric Patients: Implications for the Selection of Dosage Regimens

Background

Intravenous colistin is widely used to treat infections in pediatric patients. Unfortunately, there is a paucity of pharmacological information to guide the selection of dosage regimens. The daily dose recommended by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) is the same body weight–based dose traditionally used in adults. The aim was to increase our understanding of the patient factors that influence the plasma concentration of colistin, and assess the likely appropriateness of the FDA and EMA dosage recommendations.

Methods

There were 5 patients, with a median age of 1.75 (range 0.1–6.25) years, a median weight of 10.7 (2.9–21.5) kg, and a median creatinine clearance of 179 (44–384) mL/min/1.73m2, who received intravenous infusions of colistimethate each 8 hours. The median daily dose was 0.21 (0.20–0.21) million international units/kg, equivalent to 6.8 (6.5–6.9) mg of colistin base activity per kg/day. Plasma concentrations of colistimethate and formed colistin were subjected to population pharmacokinetic modeling to explore the patient factors influencing the concentration of colistin.

Results

The median, average, steady-state plasma concentration of colistin (Css,avg) was 0.88 mg/L; individual values ranged widely (0.41–3.50 mg/L), even though all patients received the same body weight–based daily dose. Although the daily doses were ~33% above the upper limit of the FDA- and EMA-recommended dose range, only 2 patients achieved Css,avg ≥2mg/L; the remaining 3 patients had Css,avg <1mg/L. The pharmacokinetic covariate analysis revealed that clearances of colistimethate and colistin were related to creatinine clearance.

Conclusions

The FDA and EMA dosage recommendations may be suboptimal for many pediatric patients. Renal functioning is an important determinant of dosing in these patients.

Respiratory viral infections in infants with possible sepsis

Background

Knowledge of infections leading to sepsis is needed to develop comprehensive infection prevention and sepsis, as well as early recognition and treatment strategies.The aim of this study was to investigate the etiology of sepsis and evaluate the proportion of respiratory viral pathogens in infants under two years of age with possible sepsis.

Methods

The prospective study was performed in two years. Multiplex reverse transcriptase polymerase chain reaction (RT‐PCR) was performed to detect viral pathogens. All patients who were included in this study had sepsis symptoms as defined by the Surviving Sepsis Campaign.

Results

We compared 90 patients with sepsis into three groups as patients (n = 33) who had only viral positivity in nasopharyngeal swab, patients (17) had proven bacterial infection with or without viral infection, and patients (40) without the pathogen detection. Human rhinovirus (16.7%) and influenza (7.8%) were the most commonly seen viruses. A cough was more common in the viral infection group than other groups ( P = 0.02) and median thrombocyte count was lower in the bacterial infection group than the others ( P = 0.01). Patients having bacterial sepsis had the longest duration of hospitalization than the other groups ( P = 0.04). During winter and spring seaons, patients with sepsis had more viral infection; however, in summer and autumn period, patients were mostly in a state that we could not prove infection agents ( P = 0.02).

Conclusions

Our results suggest that respiratory tract viruses may play an important role in patients with sepsis and they should be kept in mind, especially during winter and spring seasons. In overall infection, viral respiratory viruses as a single pathogen with a detection rate of 36.6% in sepsis etiology.

Epidemiology and Antibiotic Resistance Phenotypes of Diarrheagenic Escherichia Coli Responsible for Infantile Gastroenteritis in Ouagadougou, Burkina Faso

The emergence and persistence of multidrug-resistant (MDR) diarrheagenic Escherichia coli (DEC) causing acute diarrhea is a major public health challenge in developing countries. The aim of this study was to evaluate the resistance phenotypes of DEC isolated from stool samples collected from children less than 5 years of age with acute diarrhea living in Ouagadougou/Burkina Faso. From August 2013 to October 2015, this study was carried out on 31 DEC strains of our study conducted in "Centre Médical avec Antenne Chirurgicale (CMA)" Paul VI and CMA of Schiphra. DEC were isolated and identified by standard microbiological methods and polymerase chain reaction (PCR) method was used to further characterize them. Antimicrobial susceptibility testing was done based on the disk diffusion method. DEC isolates were high resistant to tetracycline (83.9%), amoxicillin (77.4%), amoxicillin clavulanic acid (77.4%), piperacillin (64.5%), and colistin sulfate (61.3%). The most resistant phenotype represented was the extended spectrum β-lactamase (ESBL) phenotype (67.7%). Aminoglycosides were 100% active on enteroinvasive E. coli (EIEC) and enterohemorrhagic E. coli (EHEC). All the DEC isolates exhibited absolute (100%) sensitivity to ciprofloxacin. Monitoring and studying the resistance profile of DEC to antibiotics are necessary to guide probabilistic antibiotic therapy, especially in pediatric patients.

Bloodstream infections in children caused by carbapenem-resistant versus carbapenem-susceptible gram-negative microorganisms: Risk factors and outcome

Carbapenems are often considered the last resort agents reserved for treatment of infections due to highly antimicrobial resistant organisms such as A. baumannii and P. aeruginosa. However, carbapenem-resistant Gram-negative (CRGN) pathogens have become much more prevalent in the last decade. The objective of this study was to determine risk factors for and outcome of bacteremia caused by Gram-negative microorganisms in a pediatric tertiary-care hospital. Among 97 patients with hospital-acquired Gram-negative bacteremia, 66 patients with carbapenem-susceptible Gram-negative pathogens (CSGN) were compared with the remaining 31 with CRGN isolates. The overall clinical response and microbiological response rates were 83.3% and 43.9% in CSGN group, and 54.8% and 32.3% in CRGN group, respectively (P=0.002 and P=0.004, respectively). The treatment failure and relapse rates were 18.2% and 6.1% in CSGN group, and 38.7% and 6.5% in CRGN group, respectively (P=0.03 in each). The infection-related mortality rates were 10.8% in the CSGN group and 32.3% in the CRGN group (P=0.01). The total length of stay in hospital before infection was longer in patients with CRGN bacteremia than that of the CSGN bacteremia (P=0.002). The extended spectrum antibiotic usage prior to infection was significantly different between the groups (P=0.008). Infections due to CRGN are generally associated with poorer patient outcomes. Longer hospital stay and extended spectrum antibiotic usage prior to infection are the most important risk factors for CRGN bacteremia in our cohort.