Carbapenem-resistant enterobacteriaceae: an emerging problem in children

Emergence of ceftazidime-avibactam resistance in blaKPC-33-harbouring ST11 Klebsiella pneumoniae in a paediatric patient

Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses immense threats to the health of infected patients worldwide, especially children. This study reports the infection caused by CRKP in a paediatric intensive care unit (PICU) child and its drug-resistant mutation during the treatment. Twelve Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae strains were isolated from the child. Broth microdilution method, plasmid transformation assay, and whole genome sequencing (WGS) were performed to investigate the antimicrobial susceptibility, resistance mechanisms, and genetic structural features of CRKPs. The results showed that 12 strains were highly resistant to most available antimicrobial agents. Among them, K. pneumoniae FD11 and K. pneumoniae FD12 were resistant to ceftazidime-avibactam (CZA, MIC >64 mg/L) and restored the carbapenem susceptibility (Imipenem, MIC =0.25 mg/L; Meropenem, MIC =2 mg/L). The patient improved after treatment with CZA in combination with aztreonam. Plasmid transformation assay demonstrated that the blaKPC-33-positive transformant increased MICs of CZA by at least 33-fold and 8-fold compared with the recipient Escherichia coli DH5α and blaKPC-2-positive transformants. WGS analysis revealed that all strains belonged to the ST11-KL64 type and showed highly homologous (3-26 single nucleotide polymorphisms [SNPs]). A single base mutation (G532T) of blaKPC-2 resulted in a tyrosine to aspartic acid substitution at Ambler amino acid position 179 (D179Y), which conferred CZA resistance in K. pneumoniae. This is the first report of a drug-resistant mutation evolving into blaKPC-33 during the treatment of blaKPC-2-positive CRKP in paediatric-infected patients. It advises clinicians that routine sequential antimicrobial susceptibility testing and KPC genotyping are critical during CZA therapy in children infected with CRKP.

Clone dissemination of IncX3 plasmid carrying blaNDM-1 in ST76 carbapenem resistance Klebsiella pneumoniae and bactericidal efficiency of aztreonam combined with avibactam in vitro and in vivo

OBJECTIVES

The rapid spread of the New Delhi Metal-β-lactamase-1 (NDM-1) gene in Klebsiella pneumoniae poses a substantial challenge to pediatric therapeutic care. Here, we aimed to characterise the IncX3-type plasmid carrying the blaNDM-1 gene in ST76 carbapenem resistance K. pneumoniae (CRKP) strains and assess the in vitro and in vivo bactericidal efficacy of Aztreonam (ATM) combined with Avibactam (AVI) (ATM+AVI) against CRKP.

METHODS

The broth microdilution method and PCR were used to detect antimicrobial susceptibility and antibiotic resistance genes. Genetic relatedness was determined using Pulsed-Field Gel Electrophoresis (PFGE) and Multilocus Sequence Typing (MLST). The plasmid conjugation assay was used to verify the transmissibility of drug-resistant plasmids. Whole-Genome Sequencing (WGS) was employed to elucidate the genomic attributes of the genes. The Fractional Inhibitory Concentration (FIC) was calculated based on the checkerboard titration assay to determine the antimicrobial effect of ATM+AVI. The time-kill curve assay and a mouse anti-infection model were used to investigate the in vitro and in vivo bactericidal efficiency of ATM+AVI.

RESULTS

Seven blaNDM-1-producing strains were found to be highly resistant to carbapenems, and they all belonged to the same sequence type (ST76) and were classified into the same PFGE clusters with an 89.1% similarity. The conjugation assay showed that the blaNDM-1-carrying plasmid was successfully transferred to Escherichia coli 600, resulting in transconjugants with carbapenem antibiotic resistance. A 54-kb IncX3 plasmid (pNDM-XZA88) carried the blaNDM-1 gene located on a Tn125 transposon-like element structure, demonstrating the transferability of resistance genes. Genome comparative analysis revealed that pNDM-XZA88 was highly similar to pCQ17 × 3 and pRor-30818cz and had relatively conserved backbones and variable accessory regions compared to the other four plasmids (pC39-334 kb, pNDM-1-DY1928, pNDM-K725, and pNDM-Z244). The checkerboard titration and time-kill curve assays revealed that the ATM+AVI combination therapy exerted significant bactericidal efficacy against the blaNDM-1-producing strains in vitro. The ATM+AVI combination also significantly reduced the bacterial burden in a mouse infection model constructed using the blaNDM-1-producing K. pneumoniae.

CONCLUSION

This study demonstrated the clone dissemination of blaNDM-1-harboring IncX3 plasmids among the ST76 K. pneumoniae isolated from pediatric patients. Therefore, more attention should be paid to preventing this high-risk clone from harming pediatric patients. Moreover, we deduced that the ATM+AVI combination therapy is an effective strategy for treating blaNDM-1-producing K. pneumoniae.

Carbapenem-resistant Enterobacterales in Children at 18 US Health Care System Study Sites: Clinical and Molecular Epidemiology From a Prospective Multicenter Cohort Study

Background

Carbapenem-resistant Enterobacterales (CRE) are an urgent public health threat in the United States.

Objective

Describe the clinical and molecular epidemiology of CRE in a multicenter pediatric cohort.

Methods

CRACKLE-1 and CRACKLE-2 are prospective cohort studies with consecutive enrollment of hospitalized patients with CRE infection or colonization between 24 December 2011 and 31 August 2017. Patients younger than age 18 years and enrolled in the CRACKLE studies were included in this analysis. Clinical data were obtained from the electronic health record. Carbapenemase genes were detected using polymerase chain reaction and whole-genome sequencing.

Results

Fifty-one children were identified at 18 healthcare system study sites representing all U.S. census regions. The median age was 8 months, with 67% younger than age 2 years. Median number of days from admission to culture collection was 11. Seventy-three percent of patients had required intensive care and 41% had a history of mechanical ventilation. More than half of children had no documented comorbidities (Q1, Q3 0, 2). Sixty-seven percent previously received antibiotics during their hospitalization. The most common species isolated were Enterobacter species (41%), Klebsiella pneumoniae (27%), and Escherichia coli (20%). Carbapenemase genes were detected in 29% of isolates tested, which was lower than previously described in adults from this cohort (61%). Thirty-four patients were empirically treated on the date of culture collection, but only 6 received an antibiotic to which the CRE isolate was confirmed susceptible in vitro. Thirty-day mortality was 13.7%.

Conclusions

CRE infection or colonization in U.S. children was geographically widespread, predominantly affected children younger than age 2 years, associated with significant mortality, and less commonly caused by carbapenemase-producing strains than in adults.

Incidence, pathogens and antimicrobial resistance of blood and cerebrospinal fluid isolates from a tertiary neonatal unit in South Africa: A 10 year retrospective review

OBJECTIVE

To determine trends in incidence, etiology and antimicrobial susceptibility of blood and cerebrospinal fluid (CSF) culture confirmed infections in hospitalized infants in a large tertiary neonatal unit in South Africa.

METHODS

Single-center, retrospective review of laboratory records of bacteria and fungi, and their susceptibility profiles, isolated from blood and CSF of infants hospitalized in the neonatal unit at Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa, from 1st January 2010 to 31st December 2019. Laboratory data on isolates and their antimicrobial susceptibilities were collected. Coagulase-negative Staphylococcus, Corynebacteria and Bacillus spp. were excluded. Patient-level clinical and laboratory data were not available.

RESULTS

There were 8,319 significant isolates, giving an infection rate of 14.3/1000 patient-days. Infection rates increased from 12.0 to 15.7/1000 patient-days (estimated average yearly change 0.6[95%CI, 0.5-0.7];p = <0.001). Gram-negative infection rates increased from 4.3 to 10.8/1000 patient-days (estimated average yearly change 0.7[95%CI,0.6-0.8];p = <0.001). The 2 most commonly isolated Gram-negative organisms were Acinetobacter baumannii (44%) and Klebsiella pneumoniae (39%). Carbapenem resistance was seen in 31% of all Gram-negatives and increased over time (estimated average yearly change 4.8%[95%CI,4.2%-5.3%];p<0.001). Gram-positive infection rates decreased (estimated average yearly change -0.1[95%CI,-0.2- -0.05];p = <0.001). Staphylococcus aureus was the most common Gram-positive isolated. Rates of methicillin-resistant Staphylococcus aureus decreased from 91% to 55%(estimated average yearly change -2.8%[95%CI,-3.5%-2%],p< 0.001). Rates of fungal isolates decreased (estimated average yearly change -0.06[95%CI,-0.1 --0.02]);p = 0.007). Candida parapsilosis (52%) and Candida albicans (35%) were the most common fungi isolated.

CONCLUSIONS

There has been a marked overall increase in rates of blood and/or CSF infections, with an absolute increase in Gram-negative infections observed, replacing Gram-positive and fungal pathogens. Extended spectrum beta-lactamase Gram-negative isolates are being replaced by carbapenem resistance, with around one third of all significant Gram-negative isolates now carbapenem resistant. Research into hospital based novel treatment and prevention interventions for neonatal sepsis should be urgently prioritized.

Prevalence and Outcomes of Carbapenem-resistant Bloodstream Infection in Children With Cancer

INTRODUCTION

Carbapenem-resistant (CR) infections cause major morbidity and mortality. Data on CR infections in children with cancer are scarce, especially from the developing world. The aim of this study was to evaluate the characteristics and outcomes of bacteremia with CR organisms (CRO) compared with bacteremia with Carbapenem-sensitive organisms in children with cancer.

METHODS

This retrospective observational study was conducted in a tertiary pediatric oncology center in South India. Data on all bloodstream infections with Gram-negative organisms (CRO and Carbapenem sensitive-organisms) in children with malignancy ≤14 years of age from August 2017 to July 2021 were retrieved. The outcome was determined as survival and all-cause death 28 days after the date of Bloodstream infection (BSI) onset.

RESULTS

Sixty-four Gram-negative BSI were identified, with 24% (n=15) in the Carbapenem-Resistant Bloodstream Infection (CR-BSI) group and 76% (n=49) in the Carbapenem-sensitive-Bloodstream Infection group. The patients included 35 males (64%) and 20 females (36%), with ages ranging from 1 year to 14 years (median age: 6.2 y). The most common underlying disease was hematologic malignancy (92.2%, n=59). Children with CR-BSI had a higher incidence of prolonged neutropenia, septic shock, pneumoniae, enterocolitis, altered consciousness, and acute renal failure and were associated with 28-day mortality in univariate analysis. The most common carbapenem-resistant Gram-negative bacilli isolates were Klebsiella species (47%) and Escherichia coli (33%). All carbapenem-resistant isolates were sensitive to colistin, and 33% were sensitive to Tigecycline. The case-fatality rate was 14% (9/64) in our cohort. The overall 28 days mortality was significantly higher in patients with CR-BSI than in those with Carbapenem-sensitive Bloodstream Infection (28-day mortality: 43.8% vs. 4.2%, P =0.001).

CONCLUSIONS

Bacteremia with CRO has higher mortality in children with cancer. Prolonged neutropenia, pneumoniae, septic shock, enterocolitis, acute renal failure, and altered consciousness were predictors of 28-day mortality in carbapenem-resistant septicemia.

Metagenomics analysis of the neonatal intestinal resistome

Introduction

The intestinal microbiome forms a major reservoir for antibiotic resistance genes (ARGs). Little is known about the neonatal intestinal resistome.

Objective

The objective of this study was to investigate the intestinal resistome and factors that influence the abundance of ARGs in a large cohort of neonates.

Methods

Shotgun metagenomics was used to analyse the resistome in stool samples collected at 1 week of age from 390 healthy, term-born neonates who did not receive antibiotics.

Results

Overall, 913 ARGs belonging to 27 classes were identified. The most abundant ARGs were those conferring resistance to tetracyclines, quaternary ammonium compounds, and macrolide-lincosamide-streptogramin-B. Phylogenetic composition was strongly associated with the resistome composition. Other factors that were associated with the abundance of ARGs were delivery mode, gestational age, birth weight, feeding method, and antibiotics in the last trimester of pregnancy. Sex, ethnicity, probiotic use during pregnancy, and intrapartum antibiotics had little effect on the abundance of ARGs.

Conclusion

Even in the absence of direct antibiotic exposure, the neonatal intestine harbours a high abundance and a variety of ARGs.

Molecular characteristics and virulence factors of carbapenem-resistant Klebsiella pneumoniae among pediatric patients in Shanghai, China

We retrospectively investigated CRKP isolates among 92 pediatric patients (32 neonates and 60 non‑neonates) in 2019 and 2020 (59 and 33 isolates, respectively) to investigate the molecular characteristics and virulence factors of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolated from pediatric patients,. All the CRKP isolates were subjected to antimicrobial susceptibility testing, string testing, molecular typing of virulence and carbapenemase genes, and multilocus sequence typing. Hypervirulent K. pneumoniae (Hvkp) was defined based on the detection of the regulator of mucoid phenotype A (rmpA).Sequence type 11 (ST11) accounted for the majority of infections in both neonates (37.5%) and non‑neonates (43.3%) (P > 0.05), whereas it increased from 30.5% (18/59) in 2019 to 60.6% (20/33) in 2020 (P < 0.05). Carbapenemase gene KPC-2 was predominant in both neonates and non‑neonates (46.9% vs. 51.7%, respectively), followed by New Delhi metallo-beta-lactamase 1 (NDM-1) (34.4% vs. 28.3%, respectively) (all P > 0.05). Compared to 2019, the proportion of bla_NDM-1 decreased (44.1% vs. 6.1%) (P < 0.001), while that of bla_KPC-2 increased (40.7% vs. 66.7%) (P = 0.017) in 2020. ybtS and iutA had a higher positivity rate in KPC-2 and ST11 producers (all P < 0.05); the KPC-2-, ybtS-, and iutA-positive isolates showed relatively higher resistance to fluoroquinolones and aminoglycosides, nitrofurantoin, and piperacillin/tazobactam, respectively. Furthermore, the combined expression (95.7%, 88/92) of carbapenemase and virulence-associated genes was detected, with the carbapenemase genes bla_KPC-2 and bla_TEM-1 combined with virulence-associated genes entB, mrkD, and ybtS accounting for the highest percentage (20.7%).Carbapenemase gene mutations in the CRKP strain from 2019 to 2020 highlight the importance of dynamic monitoring. The spread of hypervirulence-associated genes in CRKP strains and the high positivity rates of ybtS and iutA in KPC-2- and ST11-producing ones signify their high virulence potential in pediatric patients.

Capsular Polysaccharide Is Essential for the Virulence of the Antimicrobial-Resistant Pathogen Enterobacter hormaechei

Nosocomial infections caused by multidrug-resistant (MDR) Enterobacter cloacae complex (ECC) pathogens are on the rise. However, the virulence strategies employed by these pathogens remain elusive. Here, we study the interaction of ECC clinical isolates with human serum to define how this pathogen evades the antimicrobial action of complement, one of the first lines of host-mediated immune defense. We identified a small number of serum-sensitive strains, including Enterobacter hormaechei strain NR3055, which we exploited for the in vitro selection of serum-resistant clones. Comparative genomics between the serum-sensitive NR3055 strain and the isolated serum-resistant clones revealed a premature stop codon in the wzy gene of the capsular polysaccharide biosynthesis locus of NR3055. The complementation of wzy conferred serum resistance to NR3055, prevented the deposition of complement proteins on the bacterial surface, inhibited phagocytosis by human neutrophils, and rendered the bacteria virulent in a mouse model of peritonitis. Mice exposed to a nonlethal dose of encapsulated NR3055 were protected from subsequent lethal infections by encapsulated NR3055, whereas mice that were previously exposed to unencapsulated NR3055 succumbed to infection. Thus, capsule is a key immune evasion determinant for E. hormaechei, and it is a potential target for prophylactics and therapeutics to combat these increasingly MDR human pathogens. IMPORTANCE Infections caused by antimicrobial resistant bacteria are of increasing concern, especially those due to carbapenem-resistant Enterobacteriaceae pathogens. Included in this group are species of the Enterobacter cloacae complex, regarding which there is a paucity of knowledge on the infection biology of the pathogens, despite their clinical relevance. In this study, we combine techniques in comparative genomics, bacterial genetics, and diverse models of infection to establish capsule as an important mechanism of Enterobacter pathogens to resist the antibacterial activity of serum, a first line of host defense against bacterial infections. We also show that immune memory targeting the Enterobacter capsule protects against lethal infection. The further characterization of Enterobacter infection biology and the immune response to infection are needed for the development of therapies and preventative interventions targeting these highly antibiotic resistant pathogens.

The Prevalence of Carbapenemase-Producing Microorganisms and Use of Novel Cephalosporins for the Treatment of Severe Infections Caused by Carbapenem-Resistant Gram-Negative Bacteria in a Pediatric Cardiac Intensive Care Unit

BACKGROUND

The spread of carbapenem-resistant organisms (CROs) is an increasingly serious threat globally, especially in vulnerable populations, such as intensive care unit (ICU) patients. Currently, the antibiotic options for CROs are very limited, particularly in pediatric settings. We describe a cohort of pediatric patients affected by CRO infections, highlighting the important changes in carbapenemase production in recent years and comparing the treatment with novel cephalosporins (N-CEFs) to Colistin-based regimens (COLI).

METHODS

All patients admitted to the cardiac ICU of the Bambino Gesù Children's Hospital in Rome during the 2016-2022 period with an invasive infection caused by a CRO were enrolled.

RESULTS

The data were collected from 42 patients. The most frequently detected pathogens were Pseudomonas aeruginosa (64%), Klebsiella pneumoniae (14%) and Enterobacter spp. (14%). Thirty-three percent of the isolated microorganisms were carbapenemase producers, with a majority of VIM (71%), followed by KPC (22%) and OXA-48 (7%). A total of 67% of patients in the N-CEF group and 29% of patients in the comparative group achieved clinical remission (p = 0.04).

CONCLUSION

The increase over the years of MBL-producing pathogens in our hospital is challenging in terms of therapeutic options. According to the present study, N-CEFs are a safe and effective option in pediatric patients affected by CRO infections.

Resistance determinants of emerging pathogens isolated from an intensive care unit as a parameter of population health conditions of the Legal Amazon microregion

Abstract Bacteria responsible for causing infections are common in hospital environments, water, soil, and food products. The infection risk is intensified by the absence of public sanitation, poor quality of life, and food scarcity. These external factors promote the dissemination of pathogens by direct contamination or biofilm formation. In this work, we identified bacterial isolates obtained from intensive care units in the southern region of Tocantins, Brazil. We compared matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) techniques and 16S ribosomal ribonucleic acid (rRNA) molecular analysis; we also performed phenotypic characterization. Fifty-six isolates characterized using morphotinctorial tests were classified as gram-positive (80.4%; n = 45) and gram-negative (19.6%; n = 11) and were resistant to several antibiotic classes; notably, we identified the blaOXA-23 resistance gene in the ILH10 isolate. Microbial identification using MALDI-TOF MS resulted in the identification of Sphingomonas paucimobilis and Bacillus circulans. 16S rRNA sequencing revealed four isolates belonging to the genera Bacillus and Acinetobacter. The similarity was superior to 99% for Acinetobacter schindleri in the Basic Local Alignment Search Tool (BLAST), grouped in the clade superior to 90%. Several strains isolated from intensive care units (ICU) were resistant to various antibiotic classes. These techniques allowed for the identification of several microorganisms of importance in public health, enabling improvements in human infection control and proving the quality of inputs, food, and water.

Antimicrobial Stewardship Programs in PICU Settings: A Systematic Review

OBJECTIVES

Development of antimicrobial stewardship programs (ASPs) is strategy for prevention and management of emergence of antimicrobial-resistant organisms. In this study, we systematically reviewed the literature on antimicrobial stewardship interventions in PICUs and analyzed approaches, structure, implementation, and outcomes of the ASPs.

DATA SOURCES

PubMed and Scopus databases were systematically searched for studies published from January 1, 2007, to December 31, 2020, reporting interventions on judicious use of antimicrobials in PICUs (last search performed February 28, 2021).

DATA SELECTION

Studies that evaluated an intervention in a PICU setting or both in PICU and other settings and reported separate results for PICU were eligible for full-text review. Studies that had implemented stewardship in the entire hospital, including the PICU, but without presenting dedicated PICU data were excluded from the analysis.

DATA EXTRACTION

The strategy of intervention, structure of ASP team, implementation, and outcomes were assessed with a checklist tool for all studies included in the analysis. Risk of bias was assessed with the Cochrane Risk-of-Bias in Nonrandomized studies of Interventions tool.

DATA SYNTHESIS

Thirteen articles were found: 11 that applied ASP in PICUs, and two at hospital level. All PICU-dedicated ASPs applied a multimodal intervention combining strategies simultaneously; audit with feedback (6/11) and facility-specific clinical practice guidelines (7/11) were the most common strategies. A multidisciplinary team was formulated in all ASPs except for three biomarker-based interventions. Six of 11 studies included techniques to enhance behavior change and one implemented a behavior-based intervention. Antibiotic consumption was evaluated in all ASPs, cost in three of 11, antibiotic resistance in one of 11, length of hospitalization in six of 11, and mortality in eight of 11. All hospital-wide ASPs used audit with feedback in addition to facility-specific clinical practice guidelines and assessed antimicrobial consumption, expenditures, length of stay, and mortality.

CONCLUSIONS

The prevalence of ASPs in PICUs is limited, and few programs follow all of the currently available recommendations.

Clonal Spread of Carbapenem-Resistant Klebsiella pneumoniae Sequence Type 11 in Chinese Pediatric Patients

Klebsiella pneumoniae often causes life-threatening infections in patients globally. Despite its notability, little is known about potential nosocomial outbreak and spread of K. pneumoniae among pediatric patients in low- and middle-income countries. Ninety-eight K. pneumoniae strains isolated from pediatric patients in a large general hospital in China between February 2018 and May 2019 were subjected to nanopore and Illumina sequencing and genomic analysis to elucidate transmission and genetic diversity. The temporal distribution patterns of K. pneumoniae revealed a cluster of sequence type 11 (ST11) strains comprising two clades. Most inferred transmissions were of clade 1, which could be traced to a common ancestor dating to mid-2017. An infant in the coronary care unit played a central role, potentially seeding transmission clusters in other wards. Major genomic changes during the outbreak included chromosomal mutations associated with virulence and gains and losses of plasmids encoding resistance. In summary, we report a nosocomial outbreak among pediatric patients caused by clonal dissemination of KPC-2-producing ST11 K. pneumoniae. Our findings highlight the value of whole-genome sequencing during outbreak investigations and illustrate that transmission chains can be identified during hospital stays. IMPORTANCE We report a nosocomial outbreak among pediatric patients caused by clonal dissemination of blaKPC-2-carrying ST11 K. pneumoniae. Strains of various sequence types coexist in the complex hospital environment; the quick emergence and spread of ST11 strains were mainly due to the plasmid-mediated acquisition of resistance genes. The spread of hospital infection was highly associated with several specific wards, suggesting the importance of genomic surveillance on wards at high risk of infection.

Carbapenem-resistant Enterobacteriaceae bloodstream infections: A case-control study from a pediatric referral hospital in Argentina

Background

Antibiotic-resistant gram-negative bloodstream infections (BSI) remain a leading cause morbidity and mortality in pediatric patients with a high impact on the public health system. Data in resource-limited countries, including those in Latin America and the Caribbean region, are scarce. The aim of the study was to identify risk factors for acquiring carbapenem-resistant Enterobacteriaceae (CRE) bacteremia in children and to assess the use of resources.

Methods

A retrospective case-control study was conducted to analyze demographic, epidemiological, clinical, microbiological, and outcome data as well as the use of resources between 2014 and 2019. Univariate and logistic regression analysis was performed in order to identify risk factors associated with CRE-BSI. The R software version 4.1.2 was used.

Results

A total of 46 cases with CRE-BSI and 92 controls with gram-negative non-CRE-BSI were included. No statistical difference was observed regarding: median age (36 months; IQR, 11.2-117 vs. 48 months, IQR 13-119), male sex (50 vs. 60%), and underlying disease (98 vs. 91%) in cases vs. controls, respectively. The most frequent mechanism of CRE bacteremia were: KPC in 74%, OXA in 15%, and NDM in 6.5%. A total of 54.3% of cases vs. 32.6 % (p = 0.016) of controls were admitted to the pediatric intensive care unit (PICU), and 48 vs. 21% (p = 0.001) required mechanical ventilation. Bacteremia secondary to intra-abdominal infection was observed in 56.5% of cases vs. 35% of controls (p = 0.032). Previous colonization with CRE was detected in 76% of cases vs. 8% of controls. Combination antimicrobial treatment was most frequent in cases vs. control (100 vs. 56.5%). No difference was observed in median length of hospital stay (22 days; IQR, 19-31 in cases vs. 17.5 days; IQR, 10-31 in controls; p = 0.8). Overall case fatality ratio was 13 vs. 5.5%, respectively. The most statistically significant risk factors included previous PICU stay (OR, 4; 95%CI, 2-8), invasive procedures/surgery (OR, 3; 95%CI, 1-7), central venous catheter placement (OR, 6.5; 95%CI, 2-19), urinary catheter placement (OR, 9; 95%CI 4-20), mechanical ventilation (OR, 4; 95%CI, 2-10), liver transplantation (OR, 8; 95%CI, 2-26), meropenem treatment (OR, 8.4; 3.5-22.6) in univariate analysis. The logistic regression model used for multivariate analysis yielded significant differences for previous meropenem treatment (OR, 13; 95%CI, 3-77; p = 0.001), liver transplantation (OR, 13; 95%CI, 2.5-100; p = 0.006), and urinary catheter placement (OR, 9; 95%CI, 1.4-94; p = 0.03).

Conclusion

CRE-BSI affects hospitalized children with underlying disease, mainly after liver transplantation, with previous urinary catheter use and receiving broad-spectrum antibiotics, leading to high PICU requirement and mortality. These risk factors will have to be taken into account in our region in order to establish adequate health policies and programs to improve antimicrobial stewardship.

A Longitudinal Study of Spontaneous Gut Decolonization of Carbapenem-resistant Gram-negative Bacteria in Neonatal and Pediatric Patients

BACKGROUND

Antibiotic exposure may convert gut microbiome to reservoir of resistant organisms, including carbapenem-resistant Gram-negative bacteria (CRGNB). Little is known about natural history of spontaneous CRGNB decolonization of neonates/children and their risk to develop CRGNB infections.

METHODS

Patients hospitalized in a tertiary care hospital (1 days to 16 years) found to be CRGNB colonized in weekly surveillance cultures during hospitalization (January 2018 to December 2019) were prospectively followed after discharge with monthly rectal cultures for 12 months after colonization until decolonization (3 consecutive negative rectal cultures, ≥1 week apart). Patient demographics, clinical characteristics and CRGNB infections were recorded. Polymerase chain reaction for carbapenemases was performed in patients colonized, after 3 negative cultures, at the day of the last negative and the day of the first new positive culture.

RESULTS

One-hundred thirty patients (median age, 1.3 months; lower-upper quartile values, 0.8-6.9 months) were studied including 66 neonates (median age, 12.6 days; Q1-Q3, 5-18.5 days). Among patients >30 days old, 51.6% achieved decolonization within 6 months, and among neonates, 91% achieved decolonization within 6 months. By 12th month, 89% of >30 days and 100% of neonates were decolonized. Forty-four (33.9%) patients (59% >30 days and 9% neonates) developed CRGNB infection(s), mainly pneumonia (25%) and bloodstream infection (20.5%). Prolonged colonization (odds ratio [OR], 7.75; 95% confidence interval [CI], 2.10-28.58), duration of broad-spectrum antibiotic use (OR, 1.22; 95% CI, 1.11-1.34) and parenteral nutrition (OR, 4.53; 95% CI, 1.14-17.94) were associated with the development of CRGNB infection. Two patients (1.5%) were found by polymerase chain reaction colonized after 3 negative cultures.

CONCLUSIONS

Spontaneous decolonization occurs in most CRGNB colonized >30 days and all neonates within 12 months. One-third of colonized patients develop CRGNB infection(s). These findings may help optimize duration of contact precautions and empirical antimicrobial therapy for CRGNB colonized pediatric patients.

Epidemiology and clinical characteristics of infection/colonization due to carbapenemase-producing Enterobacterales in neonatal patients

Background

The aim of this study was to elucidate the epidemiological features of carbapenemase-producing Enterobacterales (CPE) in the pediatric and neonatal patients, to describe clinical characteristics of neonatal patients with CPE infections, and to assess risk factors for neonatal rectal colonization with CPE.

Results

A total of 439 carbapenem-resistant Enterobacterales (CRE) isolates recovered from 367 infant patients were characterised, including 397 isolates of Klebsiella pneumoniae (KP) and 42 isolates of Escherichia coli (EC). Carbapenemase gene blaNDM-1 was the most commonly detected, accounting for 86.56% (n = 380), followed by blaKPC-2 (9.11%, 40) and blaIMP-4 (4.33%, 19). MLST analysis showed 17 different STs detected within CPKP isolates, with ST20, ST2068, ST36 and ST17 being the most frequently isolated types. Eleven STs were identified within CPEC isolates, with ST325 being the dominant types. Eight isolates of NDM-1 producing KP, belonging to ST23, were identified as having hypervirulent traits. The main infections caused by CPE were pneumonia (n = 90) and sepsis (n = 16). All infected patients received monotherapy, with meropenem and ciprofloxacin being the most commonly used antibiotics. All pneumonia patients were cured or improved after treatment. Of the 16 patients with sepsis, 9 were cured or improved, 3 died, and 4 abandoned treatment without any clinical improvement. The rectal prevalences of CPE in the 0–3 days old (DO), the 4–28 DO, and the 29 DO-1 year old groups were decreased from 15.31%, 27.37% and 14.29% in the first stool screening period to 11.78%, 19.59% and 4.07% in the second stool screening period, respectively. Multivariate analysis showed that cesarean section, acidosis, respiration failure, gastric lavage and enema were independent risk factors for rectal colonization in the 0–3 DO group, whereas cesarean section, cephalosporins, gastric lavage and residence in rural area were independently associated with rectal colonization in the 4–28 DO group. The implementation of a series of evidence-based control measures eventually contained the CPE transmission.

Conclusions

Continued vigilance, epidemiological studies, and multimodal infection prevention strategies are urgently needed due to frequent importations.

Risk factors for antibiotic-resistant bacteria colonisation in children with chronic complex conditions

To assess drug-resistant bacterial colonisation rates and associated risk factors in children with complex chronic conditions admitted to a national reference unit in Spain. Cross-sectional study that included all children admitted to our unit from September 2018 to July 2019. Rectal swabs were obtained to determine multidrug-resistant Gram-negative bacilli (MR-GNB) colonisation, and nasal swab to determine S. aureus and methicillin-resistant S. aureus (MRSA) colonisation. Medical records were reviewed. 100 children were included, with a median of four complex chronic conditions. Sixteen percent had S. aureus colonisation, including two MRSA. S. aureus colonisation was associated with technology-dependent children, while being on antibiotic prophylaxis or having undergone antibiotic therapy in the previous month were protective factors. The prevalence of MR-GNB colonisation was 27%, which was associated with immunosuppressive therapy (aOR 31; 2.02–47]; p = 0.01), antibiotic prophylaxis (aOR 4.56; 1.4–14.86; p = 0.012), previously treated skin-infections (aOR 2.9; 1.07–8.14; p = 0.03), surgery in the previous year (aOR 1.4; 1.06–1.8; p = 0.014), and hospital admission in the previous year (aOR 1.79; [1.26–2.56]; p = 0.001). The rate of S. aureus nasal colonisation in this series was not high despite the presence of chronic conditions, and few cases corresponded to MRSA. Antibiotic prophylaxis, immunosuppressive therapies, history of infections, previous surgeries, and length of admission in the previous year were risk factors for MR-GNB colonisation.

Is Carbapenem-resistant Klebsiella pneumoniae Infection in Pediatric Bone Marrow Transplantation Recipients Inevitably Fatal?

Carbapenem resistance, most notably in Klebsiella pneumonia (KPC), results in infections associated with significant morbidity and mortality. Here we report 2 cases of adolescent patients with KPC infection after high-risk bone marrow transplantation, who eventually succumbed from other causes and review the epidemiology and treatment options for KPC infections in this vulnerable population.

Risk factors for the colonization or infection of carbapenem-resistant Enterobacteriaceae in children: a Meta analysis

OBJECTIVES

To systematically assess the risk factors for the colonization or infection of carbapenem-resistant Enterobacteriaceae in children.

METHODS

PubMed, Web of Science, China National Knowledge Infrastructure Database, Wanfang Data, China Biology Medicine disc were searched to obtain the articles on risk factors for the colonization or infection of carbapenem-resistant Enterobacteriaceae in children published up to May 31, 2021. RevMan 5.3 software was used to perform the Meta analysis.

RESULTS

A total of 13 articles were included, with 1 501 samples in total. The Meta analysis showed that indwelling gastric tube (OR=4.91), tracheal intubation (OR=5.03), central venous catheterization (OR=3.75), indwelling urinary catheterization (OR=4.11), mechanical ventilation (OR=3.09), history of hospitalization in the intensive care unit (OR=2.39), history of surgical operation (OR=3.22), previous use of third-generation cephalosporins (OR=2.62), previous use of carbapenem antibiotics (OR=3.82), previous use of glycopeptide antibiotics (OR=3.48), previous use of β-lactamase inhibitors (OR=2.87), previous use of antifungal drugs (OR=2.48), previous use of aminoglycoside antibiotics (OR=2.54), and Apgar score ≤7 at 1 minute after birth (OR=2.10) were risk factors for the colonization or infection of carbapenem-resistant Enterobacteriaceae in children (P<0.05).

CONCLUSIONS

Invasive operations, history of hospitalization in the intensive care unit, previous use of antibiotics such as carbapenem antibiotics, and Apgar score ≤7 at 1 minute after birth are risk factors for the colonization or infection of carbapenem-resistant Enterobacteriaceae in children.

Clinical outcome of neonates with Carbapenem-resistant Enterobacteriaceae infections at the King Edward VIII Hospital's neonatal unit, Durban, South Africa

Background

Carbapenem-resistant infections in neonates are increasing worldwide. These organisms are associated with poor outcomes because of the severity of the disease, lack of treatment options and impaired immune systems of premature neonates. These infections are associated with significantly higher morbidity, mortality and prolonged hospitalisations, especially in developing countries.

Methods

A retrospective study was conducted to evaluate the prevalence and clinical outcomes of neonates with Carbapenem-resistant Enterobacteriaceae (CRE) infection over 24 months, from January 2015 to December 2016. All charts for neonates with positive cultures were reviewed, including characteristics of neonates that acquired the infection, possible risk factors and outcomes.

Results

A total of 32 cases were included with a prevalence of 5/1000 admissions. The mortality rate was 0.6/1000, with case facility rate at 12.5%. Most neonates developed CRE infections within the first 7 days of admission. There was an equal distribution between early neonatal deaths (ENND) and late neonatal deaths (LNND). Neonates (34.4%) had prior exposure to Carbapenem, with a higher mortality rate of (75%). There was zero mortality in the HIV-exposed group.

Conclusion

Neonates developed CRE much earlier than previously reported. Invasive procedures on admission carry an associated higher risk for developing CRE, more than the length of stay as previously stipulated. Prevalence of CRE seems to be high in middle-income countries with higher mortality. Thus, strict infection prevention and control (IPC) measures during admission and during the first weeks of life can decrease the incidence and outcome of CRE-related mortality and morbidity.

Development and validation of a UHPLC-MS/MS method to measure cefotaxime and metabolite desacetylcefotaxime in blood plasma: a pilot study suitable for capillary microsampling in critically ill children

Critical illness has been shown to affect the pharmacokinetics of antibiotics, which can lead to ineffective antibiotic exposure and the potential emergence of resistant bacteria. The lack of studies describing antibiotic pharmacokinetics in critically ill children has led to significant off-label dosing. This is, in part, due to the ethical and physiological challenges of removing frequent, large-volume samples from children. Capillary microsampling facilitates the collection of small volumes of blood samples to conduct clinical pharmacokinetic studies. A sensitive, rapid, and accurate ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) bioanalytical method to measure cefotaxime and desacetylcefotaxime in 2.8 μL of plasma was developed and validated. Plasma samples were treated with acetonitrile and analytes were separated using a Kinetex C8 (100 × 2.1 mm) column. The chromatographic separation was established using a gradient method, with the mobile phases consisting of acetonitrile and ammonium acetate. An electrospray ionization source interface operated in a positive mode for the multiple reaction monitoring MS/MS analysis of cefotaxime, desacetylcefotaxime, and deuterated cefotaxime (internal standard). The bioanalytical method using microsample volumes met requirements for method validation for both analytes. Cefotaxime had precision within ± 7.3% and accuracy within ± 5% (concentration range of 0.5 to 500 mg/L). Desacetylcefotaxime had precision within ± 9.5% and accuracy within ± 3.5% (concentration range of 0.2 to 10 mg/L). The bioanalytical method was applied for the quantification of cefotaxime and its metabolite to 20 capillary microsamples collected at five time points in one dosing interval from five critically ill children.

Highlights Regarding the Use of Metallic Nanoparticles against Pathogens Considered a Priority by the World Health Organization

The indiscriminate use of antibiotics has facilitated the growing resistance of bacteria, and this has become a serious public health problem worldwide. Several microorganisms are still resistant to multiple antibiotics and are particularly dangerous in the hospital and nursing home environment, and to patients whose care requires devices, such as ventilators and intravenous catheters. A list of twelve pathogenic genera, which especially included bacteria that were not affected by different antibiotics, was released by the World Health Organization (WHO) in 2017, and the research and development of new antibiotics against these genera has been considered a priority. The nanotechnology is a tool that offers an effective platform for altering the physicalchemical properties of different materials, thereby enabling the development of several biomedical applications. Owing to their large surface area and high reactivity, metallic particles on the nanometric scale have remarkable physical, chemical, and biological properties. Nanoparticles with sizes between 1 and 100 nm have several applications, mainly as new antimicrobial agents for the control of microorganisms. In the present review, more than 200 reports of various metallic nanoparticles, especially those containing copper, gold, platinum, silver, titanium, and zinc were analyzed with regard to their anti-bacterial activity. However, of these 200 studies, only 42 reported about trials conducted against the resistant bacteria considered a priority by the WHO. All studies are in the initial stage, and none are in the clinical phase of research.

Potential Effectiveness of Piperacillin/Tazobactam in Treating Pediatric Patients Infected with IMP-Type Carbapenemase-Producing Enterobacteriaceae

Background: The resistance rate of carbapenem-resistant Enterobacteriaceae (CRE) is increasing yearly but rarely reported in children. Objectives: This retrospective study analyzed the characteristics of isolated CRE strains in pediatric patients, intending to explore reasonable antimicrobial treatment options. Methods: Some CRE isolates were collected from infected pediatric patients in Liaocheng People’s Hospital from January 2014 to December 2019. The strain identification and antimicrobial susceptibility testing were conducted using Vitek mass spectrometry and the Vitek 2 system, respectively. The carbapenemase genotypes of blaKPC, blaIMP, blaVIM, blaNDM-1, and blaOXA-48 were each detected by polymerase chain reaction and sequencing. The molecular homology analysis of strains was conducted via Pulse-field Gel Electrophoresis (PFGE). The clinical data of CRE-infected pediatric patients were collected from the hospital’s medical data information system. Results: Twenty CRE strains were isolated from 1945 infected pediatric patients with Enterobacteriaceae. All CRE strains showed multiple resistance to commonly used antimicrobials. Twelve strains of imipenemase (IMP)-4 and seven strains of IMP-8 carbapenemase were confirmed. Besides, PFGE revealed that two strains of Escherichia coli and three of Klebsiella pneumoniae had indistinguishable patterns. Sixteen patients were cured, including 10 patients using piperacillin/tazobactam. Conclusions: This study found the major sources of resistance were IMP carbapenemases. Piperacillin/tazobactam is potentially effective for the treatment of CRE infection, despite insensitivity in vitro.

Clinical Molecular Epidemiology of Carbapenem-Resistant Klebsiella pneumoniae Among Pediatric Patients in Jiangsu Province, China

PURPOSE

The continuous emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a serious public health problem globally, especially for children, but data on CRKP infection in pediatric patients are limited. This study aimed to identify epidemiological and molecular patterns of CRKP among pediatric patients in Jiangsu province, China.

PATIENTS AND METHODS

CRKP were consecutively collected from the Children's Hospital of Nanjing Medical University in China from July 2018 to May 2019. Then, CRKP strains were performed for further study: antimicrobial susceptibility testing, drug-resistance determinants screening and homology analysis.

RESULTS

We collected 94 CRKP from 94 children. Overall, bla KPC-2 (79.8%) was the predominant carbapenemase gene, followed by bla NDM-1(14.9%), bla IMP-4 (5.3%) and bla NDM-5(4.3%). Notably, two isolates coharbored bla KPC-2 and bla IMP-4, and two isolates coharbored bla KPC-2 and bla NDM-5. MLST analysis revealed that 14 distinct sequence types (STs) were identified, of which ST11 was the most common sequence type identified. Moreover, two novel STs, ST4854 and ST4855, were detected in this study. PFGE revealed that a predominant cluster consisting of KPC-2-producing CRKP ST11 clone isolates was identified and was distributed mainly in the pediatric intensive care unit (PICU) and cardiac intensive care unit (CCU). Moreover, this is the first report to identify the dissemination of ST716 CRKP coproducing KPC-2 and IMP-4 clones.

CONCLUSION

Clonal dissemination of KPC-2-producing CRKP ST11 was observed in multiple departments. Moreover, two novel STs (ST4854 and ST4855) were identified, which indicates an increased diversity of CRKP strains. To our knowledge, this is the first report that identified the dissemination of Klebsiella pneumoniae coproducing KPC-2 and IMP-4 clones among children, which represents a significant health risk to pediatric patients. Active surveillance and effective control measures are urgently needed to prevent further transmission of these strains among children.

Molecular characteristics of the new emerging global clone ST1193 among clinical isolates of Escherichia coli from neonatal invasive infections in China

Sequence type 1193 (ST1193) constitutes an emerging fluoroquinolone-resistant Escherichia coli clone in several countries. However, reports of such isolates in neonatal invasive diseases are limited. Here, we assessed the antimicrobial resistance and molecular characteristics of E. coli ST1193 isolates causing neonatal bloodstream infections and meningitis in China. A total of 56 E. coli isolates were collected from neonatal blood and cerebrospinal fluid between September 2009 and June 2015. Antimicrobial susceptibility was evaluated using E-test methods. Polymerase chain reaction amplification was used to detect antibiotic resistance genes including bla_TEM, bla_SHV, and bla_CTX-M groups. Molecular typing was performed via multi-locus sequence typing. Among 56 E. coli isolates, 17 (17/56, 30.4%) were extended-spectrum β-lactamase (ESBL) producers, and 37(37/56, 66.1%) were multidrug-resistant. The most frequent sequence types were ST1193 (12/56), followed by ST95 and ST62. ST1193 isolates exhibited a 91.7% resistance rate to ciprofloxacin, amoxicillin, and sulfonamides, and 83.3% resistance rate to tetracycline. A total of 4 (33.3%) among the 12 ST1193 isolates were ESBL producers, of which three carried both bla_CTX-M-15 and bla_TEM genes with the remaining isolate harboring bla_CTX-M-27 and bla_TEM genes. Additionally, 1 of the 3 ST1193 isolates obtained from cerebrospinal fluid was an ESBL producer that carried both bla_CTX-M-₁₅ and bla_TEM genes. This study revealed for the first time the molecular characteristics of E. coli ST1193 causing neonatal invasive diseases in China. Notably, we found that ST1193 isolates were multidrug-resistant. Further multicenter studies are needed to assess the molecular epidemiology of ST1193 in China to control its spread.

Optimal Management of Complicated Infections in the Pediatric Patient: The Role and Utility of Ceftazidime/Avibactam

Antimicrobial resistance poses a substantial threat to global public health. The pursuit of new antibiotics has decreased and very few options have been investigated for the treatment of complicated multidrug-resistant Gram-negative (MDR-GN) infections in adult population and even less in pediatric patients. Ceftazidime-avibactam (CAZ-AVI) is novel cephalosporin/β-lactamase inhibitor (BL-BLI) combination with broad antibacterial spectrum. The aim of this review is to describe the current and future role CAZ-AVI in the pediatric population with suspected or confirmed MDR-GN infections.

Actively surveillance and appropriate patients placements' contact isolation dramatically decreased Carbapenem-Resistant Enterobacteriaceae infection and colonization in pediatric patients in China

BACKGROUND

With the increasing use of carbapenems in clinic practice, carbapenem-resistant Enterobacteriaceae (CRE) has also increased, thus posing a significant threat to human health.

AIM

To assess the effects of CRE colonization active screening and various CRE patient placements implemented in decreasing CRE infection risk.

METHODS

CRE colonization screening and various CRE patient placements were performed across CRE high-risk departments (PICU, NICU, neonatal wards and hematology departments) between 2017 and 2018, respectively.

FINDING

In 2018, more than 80% neonatal CRE positive patients were isolated using single room or same room isolation, and more than 50% non-neonatal patients were, with no cohort placement. The CRE nosocomial infection incidences decreased from 1.96% to 0.63% in NICU, and from 0.57% to 0.30% in neonatal wards (all P<0.05) while no significant changes were found in the other departments. The CRE colonization incidence at different length hospital stay (LOS) decreased at 8-14days and >14days LOS in CRE high-risk departments (all P<0.05). In addition, 62.5% clinical strains, 66.7% screening strains, and 74.1% nosocomial infection strains were belonged to CC17 complex group in neonatal isolates; while, 56.6%, 47.5% and 100% strains mentioned above were belonged to CC11 complex group in non-neonatal isolates respectively. The predominant carbapenemase gene was blaNDM-1 (98%) in neonatal and blaKPC-2 (70%) in non-neonatal CR-KP stains.

CONCLUSIONS

Active CRE colonization surveillance and CRE positive patient propriety placement may decrease the CRE infection risk. Neonatal and non-neonatal CR-KP isolates showed different CRE molecular characteristics, which could further benefit CRE infection precaution and antibiotic therapy.

Meropenem vs standard of care for treatment of neonatal late onset sepsis (NeoMero1): A randomised controlled trial

Background

The early use of broad-spectrum antibiotics remains the cornerstone for the treatment of neonatal late onset sepsis (LOS). However, which antibiotics should be used is still debatable, as relevant studies were conducted more than 20 years ago, recruited in single centres or countries, evaluated antibiotics not in clinical use anymore and had variable inclusion/exclusion criteria and outcome measures. Moreover, antibiotic-resistant bacteria have become a major problem in many countries worldwide. We hypothesized that efficacy of meropenem as a broad-spectrum antibiotic is superior to standard of care regimens (SOC) in empiric treatment of LOS and aimed to compare meropenem to SOC in infants aged <90 days with LOS.

Methods and findings

NeoMero-1 was a randomized, open-label, phase III superiority trial conducted in 18 neonatal units in 6 countries. Infants with post-menstrual age (PMA) of ≤44 weeks with positive blood culture and one, or those with negative culture and at least with two predefined clinical and laboratory signs suggestive of LOS, or those with PMA >44 weeks meeting the Goldstein criteria of sepsis, were randomized in a 1:1 ratio to receive meropenem or one of the two SOC regimens (ampicillin+gentamicin or cefotaxime+gentamicin) chosen by each site prior to the start of the study for 8–14 days. The primary outcome was treatment success (survival, no modification of allocated therapy, resolution/improvement of clinical and laboratory markers, no need of additional antibiotics and presumed/confirmed eradication of pathogens) at test-of-cure visit (TOC) in full analysis set. Stool samples were tested at baseline and Day 28 for meropenem-resistant Gram-negative organisms (CRGNO). The primary analysis was performed in all randomised patients and in patients with culture confirmed LOS. Proportions of participants with successful outcome were compared by using a logistic regression model adjusted for the stratification factors. From September 3, 2012 to November 30th 2014, total of 136 patients (instead of planned 275) in each arm were randomized; 140 (52%) were culture positive. Successful outcome at TOC was achieved in 44/136 (32%) in the meropenem arm vs. 31/135 (23%) in the SOC arm (p = 0.087). The respective numbers in patients with positive cultures were 17/63 (27%) vs. 10/77 (13%) (p = 0.022). The main reason of failure was modification of allocated therapy. Treatment emergent adverse events occurred in 72% and serious adverse events in 17% of patients, the Day 28 mortality was 6%. Cumulative acquisition of CRGNO by Day 28 occurred in 4% of patients in the meropenem and 12% in the SOC arm (p = 0.052).

Conclusions

Within this study population, we found no evidence that meropenem was superior to SOC in terms of success at TOC, short term hearing disturbances, safety or mortality were similar in both treatment arms but the study was underpowered to detect the planned effect. Meropenem treatment did not select for colonization with CRGNOs. We suggest that meropenem as broad-spectrum antibiotic should be reserved for neonates who are more likely to have Gram-negative LOS, especially in NICUs where microorganisms producing extended spectrum- and AmpC type beta-lactamases are circulating.

Emergence of an NDM-5-Producing Escherichia coli Sequence Type 410 Clone in Infants in a Children's Hospital in China

Purpose

Outbreaks of infection due to carbapenem-resistant Enterobacterales (CRE), including New Delhi metallo-β-lactamase (NDM)-producing Escherichia coli, have been increasingly reported worldwide, primarily in adults and rarely in children. The goal of this study was to characterize an outbreak of infection caused by NDM-5-producing E. coli in a children’s hospital in China.

Methods

A total of 86 CRE isolates were collected from 85 hospitalized children between June 2017 and May 2018. These isolates were subjected to multiple phenotypic and molecular tests, including in vitro antimicrobial susceptibility testing, PCR, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and whole-genome sequencing (WGS).

Results

Among the 86 CRE isolates, we identified 9 NDM-5-producing E. coli isolates, with 5 of them sharing the same PFGE pattern, same MLST type (ST410), same plasmid replicon type (IncFII), and nearly the same set of additional resistance genes. All 9 isolates were resistant to most antimicrobial agents, including carbapenems, cephalosporins, and levofloxacin, while being sensitive to trimethoprim/sulfamethoxazole, amikacin, tigecycline, and colistin. According to the clinical background, all 9 isolates were collected in a period of < 3 months from infants among whom there was overlap in the time of hospitalization. None of them had a travel history.

Conclusion

Our analysis suggests an outbreak of clonal dissemination, presumably due to nosocomial transmission. This study represents the first documented outbreak of NDM-5-producing E. coli mediated by IncFII in infants. Close monitoring is urgently needed to prevent and control the spread of this difficult-to-treat superbug.

Carbapenem-Resistant Gram-Negative Bacterial Infections in Children

Carbapenem-resistant organisms (CRO) are a major global public health threat. Enterobacterales hydrolyze almost all β-lactams through carbapenemase production. Infections caused by CRO are challenging to treat due to the limited number of antimicrobial options. This leads to significant morbidity and mortality. Over the last few years, several new antibiotics effective against CRO have been approved. Some of them (e.g., plazomicin or imipenem-cilastatin-relebactam) are currently approved for use only by adults; others (e.g., ceftazidime-avibactam) have recently been approved for use by children. Recommendations for antibiotic therapy of CRO infections in pediatric patients are based on evidence mainly from adult studies. The availability of pediatric pharmacokinetic and safety data is the cornerstone to broaden the use of proposed agents in adults to the pediatric population. This article provides a comprehensive review of the current knowledge regarding infections caused by CRO with a focus on children, which includes epidemiology, risk factors, outcomes, and antimicrobial therapy management, with particular attention being given to new antibiotics.

Analysis of the Drug Resistance of Carbapenem-Resistant Klebsiella pneumoniae in the China Antimicrobial Resistance Surveillance Trial Program, 2007-2018

Objective: To analyze the drug resistance data of carbapenem-resistant Klebsiella pneumoniae (CRKP) collected in 19 tertiary hospitals in the China Antimicrobial Resistance Surveillance Trial Program from 2007 to 2018. Methods: According to the unified plan, clinical isolates of Klebsiella pneumoniae were collected from 19 tertiary hospitals in 19 cities in mainland China. The minimum inhibitory concentrations (MIC) were determined by a twofold agar dilution method, and antimicrobial susceptibility was established. The isolates were characterized by antimicrobial susceptibility testing, and their drug resistance data were analyzed. Results: In total, 302 strains of CRKP were screened from 3,671 strains of K. pneumoniae. The clinical isolation rate of CRKP increased from 0.9% to 19.9% in the past 12 years, and the isolation rate of CRKP in pediatric patients increased the fastest, to 24.7%. Along this period, the isolation rate in the intensive care unit was higher than that in other settings. The number of CRKP strains with imipenem and meropenem MIC ≤8 mg/L decreased from 63.6% to 11.7% and from 72.7% to 14.2%, respectively. Resistance to drugs that may be used to treat drug-resistant bacterial infections has increased to varying degrees, and CRKP has the lowest resistance rate to polymyxin B (<19.0%). Conclusion: Because the MIC of CRKP is increasing each year in China, carbapenems are less likely to be used as part of combined therapy to treat CRKP infections. It is difficult to obtain good therapeutic effects against CRKP infections with MICs that are too high. CRKP is still the most sensitive to polymyxin B in vitro, followed by tigecycline. Combination therapy may be the most effective current treatment for CRKP infection.

Extensively-drug resistant Acinetobacter baumannii bacteremia in neonates: effective treatment with the combination of colistin and ampicillin/sulbactam

Acinetobacter baumannii has evolved as a major pathogen of outbreaks in the healthcare setting with increased morbidity and mortality. In neonates, treatment can be quite challenging due to the resistance profile of A. baumannii as well as limited data on pharmakokinetics and pharmakodynamics of antibiotics in this age group. We present an outbreak of eight cases of extensively-drug resistant (XDR) A. baumannii bacteremias successfully managed with the combination of colistin with high dose ampicillin/sulbactam.

Exploration of the antibiotic resistome in a wastewater treatment plant by a nine-year longitudinal metagenomic study

The spread of antibiotic resistance genes (ARGs) is a growing global problem. Activated sludge (AS) in wastewater treatment plants (WWTPs) has been proposed as a hotspot for ARGs. However, few studies have been conducted to uncover the temporal dynamics of the resistome of AS in WWTPs by long-term longitudinal sampling. In this study, we quantified ARGs and identified their host microbiome in a Hong Kong WWTP in 97 monthly AS samples spanning 9 years. Throughout this analysis, we demonstrated that both the abundance and structures of the resistome changed significantly every two to three years, implying that there was a successive selection of resistomes in the AS system over the study period. The detection of genes of antibiotic-resistant pathogens that are emerging major threats to public health in the AS samples, including mcr, CRE (carbapenem-resistant Enterobacteriaceae) and MRSA (methicillin-resistant Staphylococcus aureus)-related genes, highlight the role of WWTPs as reservoirs of ARGs. In addition, the core resistome (abundant and persistent genes) in AS were found to overlap with those in other ecosystems such as urban sewage, livestock feces, and fishpond sediments, revealing the broad dissemination of ARGs in WWTPs and other environments. Annual variation of resistomes were explained via structural equation modeling (SEM), which deciphered the structural linkages of determining factors such as the operational parameters, microbial community composition and horizontal gene transfer (HGT). Specifically, potentially relevant antibiotic resistance bacteria (ARBs) were explored and discussed based on assembly-based analyses and network correlations. Moreover, consistent with the clear relationship between resistomes and mobile genetic elements (MGEs), it was found that there was a relatively high potential for gene exchange in AS in comparison with soil genomes, which could be explained by the engineering features of WWTPs. Based on these findings, longitudinal monitoring of WWTPs is warranted for risk assessment to reveal emerging ARGs, resistome evolution, correlations with ARBs, and the potential for spread in downstream environments and concomitant exposure risks for humans.

First Reported Nosocomial Outbreak Of NDM-5-Producing Klebsiella pneumoniae In A Neonatal Unit In China

Purpose

Carbapenem-resistant Klebsiella pneumoniae (CRKP) have emerged worldwide and also being a major threat to children and neonate. In this study, we describe a nosocomial outbreak of NDM-5-producing Klebsiella pneumoniae in neonatal unit of a teaching hospital in China from September 2015 to September 2016.

Patients and methods

We collected 12 carbapenem-resistant K. pneumoniae outbreak strains from 12 newborns and characterized these isolates for their antimicrobial susceptibility, clone relationships, and multi-locus sequence types using vitek-2 compact system, pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Resistant genes were detected by using PCR and sequencing. Plasmid conjugation experiment was carried out to determine the transferability of carbapenem resistance. PCR-based replicon typing (PBRT), S1 nuclease-PFGE, and southern blotting were conducted for plasmid profiling.

Results

All 12 K. pneumoniae isolates were resistant to carbapenems and carried bla_NDM-5, bla_TEM-1 and bla_SHV-11. Furthermore, PFGE analysis showed that NDM-5-producing K. pneumoniae were clonally related and MLST assigned them to sequence type 337. Conjugative assays showed that plasmids harboring bla_NDM-5 gene were self-transmissible. Plasmid analysis suggested that all bla_NDM-5 gene located on a ~45 kb IncX3 type plasmid.

Conclusion

To the best of our knowledge, this is the first report of a clone outbreak of bla_NDM-5-carrying K. pneumoniae isolates from neonates. There is an urgent need for effective infection control measures to prevent bla_NDM-5 variants from becoming epidemic in the neonates in the future.

Systematic review of carbapenem-resistant Enterobacteriaceae causing neonatal sepsis in China

BACKGROUND

Carbapenems are β-lactam antibiotics which are used to treat severe infections caused by multidrug resistant Enterobacteriacea. The recent emergence and rapid spread of Enterobacteriaceae resistant to carbapenems is a global concern. We undertook a systematic review of the antibiotic susceptibility and genotypic characteristics of carbapenem-resistant Enterobacteriaceae in Chinese neonates.

METHODS

Systematic literature reviews were conducted (PubMed/Medline, Embase, Wanfang medical online databases, China National Knowledge Infrastructure (CNKI) database) regarding sepsis caused by carbapenem-resistant Enterobacteriaceae in Chinese neonates aged 0-30 days.

RESULTS

17 studies were identified. Eleven patients in the six studies reported the source of infection. Ten patients (10/11, 90.9%) were hospital-acquired infections. Genotypic data were available for 21 isolates in 11 studies (20 K. pneumoniae, 1 E. coli). NDM-1 was the most frequently reported carbapenem-resistant genotype (81.0%, 17/21). Carbapenem-resistant Klebsiella pneumoniae and Escherichia coli were resistant to many antibiotic classes with the exception of colistin and fosfomycin. Sequence type 105 (ST105) was the most commonly reported K. pneumoniae ST type (30.8%; 4/13), which was from the same hospital in Western China. ST17 and ST20 were the second and third most common K. pneumoniae ST type, 23.1% (3/13) and 15.4% (2/13) respectively. The three strains of ST17 are all from the same hospital in central China. The two strains of ST20, although not from the same hospital, belong to the eastern part of China.

CONCLUSIONS

Klebsiella pneumoniae with the NDM-1 genotype was the leading cause of neonatal carbapenem resistant sepsis in China. Hospital acquired infection is the main source of carbapenem resistant sepsis. There is currently no licenced antibiotic regimen available to treat such an infection in China. Improved surveillance, controlling nosocomial infection and the rational use of antibiotics are the key factors to prevent and reduce its spread.

Exploring the phenotype and genotype of multi-drug resistant Klebsiella pneumoniae harbouring blaCTX-M group extended-spectrum β-lactamases recovered from paediatric clinical cases in Shenzhen, China

Background

Emergence and spread of β-lactamase resistant Klebsiella pneumoniae have posed a serious threat, especially in paediatric patients globally. The present study focuses on explore drug resistance profile and molecular characterization of carbapenemase and extended-spectrum β-lactamase producing K. pneumoniae isolated from paediatric patients in Shenzhen, China.

Methods

Present study, a total of 31 isolates of multi-drug resistant K. pneumoniae were collected from Shenzhen Children’s Hospital, China during Jan 2014 to December 2015. ESBLs production was confirmed by using the combination disc diffusion method followed by antimicrobial susceptibility. In addition, β-lactamase encoding genes were determined by PCR assay and sequencing. The genotypic diversity and phylogenetic relationship were determined by multi-locus sequence typing (MLST) method and pulsed-field gel electrophoresis (PFGE).

Results

We examined 31, unique K. pneumoniae isolates collected from 2014 and 2015 in Shenzhen Children’s Hospital, China. All the 31 isolates 100% were resistant to ceftazidime, ertapenem, ampicillin, cefazolin and ampicillin-sulbactam followed by ceftriaxone 94% (n = 29), aztreonam 89% (n = 26), cefepime 84% (n = 26), nitrofurantoin 75% (n = 24), piperacillin 52% (n = 16), and levofloxacin 49% (n = 15). Of the 31 β-lactamase gene coding isolates, bla_CTX-M was mainly detected in about 100% (n = 31), followed by bla_KPC 71% (n = 22), bla_SHV 61% (n = 19), bla_NDM 25% (n = 8), bla_CYM 13% (n = 4), bla_OXA-48 9% (n = 3), bla_GES 9% (n = 3) and bla_TEM 6% (n = 2). Seventeen distinct sequences type were observed with ST20 being mostly identified 16% (n = 5). Pulsed-field gel electrophoresis (PFGE) typing showed that identical profile for the isolates recovered from the Department of Intensive Care Unit and Department of Neurology of our hospital. Plasmid replicon typing result indicates the presence of IncFIS type as highest in all isolates as 61% (n = 19), followed by IncFIB 23% (n = 7), IncFIA and IncFIC 16% (n = 5) each.

Conclusion

Our study reports the occurrence and spread of extended β-lactamase K. pneumoniae ST20 and ST2407 for the first time, in Shenzhen, particularly in paediatric patients. To prevent and control the infection by limiting the spread of infection-causing organisms it is very crucial to detect the presence of resistant genes at an early stage.

In vitro activity of meropenem combined with vaborbactam against KPC-producing Enterobacteriaceae in China

Background

Vaborbactam is a novel inhibitor of serine β-lactamases, including KPCs, which predominate in China. It is being developed in combination with meropenem.

Methods

Using the broth microdilution method, the in vitro activity of meropenem/vaborbactam against 128 KPC-producing Enterobacteriaceae from China was investigated.

Results

Meropenem alone showed no activity (MIC50 and MIC90 >64 mg/L), but the addition of vaborbactam potentiated meropenem in a dose-dependent manner with MIC90 decreasing from >64 to 0.5 mg/L in the presence of increasing concentrations of vaborbactam. MIC50 and MIC90 of meropenem with 8 mg/L vaborbactam (MV8) were reduced to 0.5 and 8 mg/L, respectively. MV8 (4 mg/L meropenem) inhibited 76.6% of Klebsiella pneumoniae and 100% of Escherichia coli isolates. Seventy-three (77.7%) of the K. pneumoniae isolates belonged to ST11; the remaining 22.3% of isolates were represented by 12 different STs. Of the ST11 and non-ST11 isolates, 71.2% and 95.2%, respectively, were inhibited by MV8 (4 mg/L meropenem). In 14 strains characterized for intrinsic resistance mechanisms, MV8 MIC was increased in isolates with defects in both OmpK35 and OmpK36. The highest MV8 MIC was observed in the strain that had both non-functional porins and increased expression of blaKPC and acrB.

Conclusions

Our findings suggest that meropenem/vaborbactam has good activity against KPC-producing Enterobacteriaceae from China. However, a higher percentage of K. pneumoniae isolates for which MV8 MIC was elevated compared with other geographical areas is noteworthy. This might be due to clonal dissemination of ST11 KPC-producing isolates that are defective in both major porins, OmpK35 and OmpK36.

Use of Ceftazidime-avibactam for the Treatment of Extensively drug-resistant or Pan drug-resistant Klebsiella pneumoniae in Neonates and Children <5 Years of Age

BACKGROUND

Emergence of extensively drug-resistant (XDR) or pan drug-resistant (PDR) Enterobacteriaceae is a major public threat especially for young patients. Treatment options for these bacteria are extremely limited with no safety data existing for neonates and children. Ceftazidime-avibactam has activity against Gram-negative bacteria producing Klebsiella pneumoniae carbapenemase, but virtually no data exist on its use in neonatal and pediatric patients.

METHODS

We present a single-center case series of neonates and children <5 years treated with ceftazidime-avibactam for XDR or PDR K. pneumoniae infections until August 2018. Medical records of patients who received ceftazidime-avibactam for at least 2 days (6 doses) were reviewed. Clinical, laboratory and microbiologic data were collected using a prestructured form. Adverse events and clinical/microbiologic responses and 15- and 30-day outcome were assessed.

RESULTS

In our case series, 8 patients (median age 53 days, range from 13 days to 4.5 years) received 9 courses of ceftazidime-avibactam at a dose of 62.5 mg/kg q8h for suspected or proven XDR/PDR K. pneumoniae infections including bloodstream infections (8 courses), central nervous system infections (2 courses) and urinary tract infection (1 course). All patients were critically ill and received other antibiotics prior and concomitantly with the administration of ceftazidime-avibactam. There was no treatment discontinuation due to adverse events. Clinical and microbiologic responses occurred in all patients, and no patient died by day 30.

CONCLUSIONS

Administration of ceftazidime-avibactam appears to be well tolerated and efficacious against in vitro susceptible XDR or PDR Enterobacteriaceae without being associated with significant adverse events.

Antibiotics and Cure Rates in Childhood Febrile Urinary Tract Infections in Clinical Trials: A Systematic Review and Meta-analysis

PURPOSE

Urinary tract infections (UTIs) are common bacterial infections among children.

OBJECTIVE

To systematically review the antimicrobials used for febrile UTIs in paediatric clinical trials and meta-analyse the observed cure rates and reasons for treatment failure.

MATERIALS AND METHODS

We searched Medline, Embase and Cochrane central databases between January 1, 1990, and November 24, 2016, combining MeSH and free-text terms for: "urinary tract infections", AND "therapeutics", AND "clinical trials" in children (age range 0-18 years). Two independent reviewers assessed study quality and performed data extraction. The major outcome measures were clinical and microbiological cure rates according to different antibiotics.

RESULTS

We identified 2762 published studies and included 30 clinical trials investigating 3913 cases of paediatric febrile urinary tract infections. Children with no underlying condition were the main population included in the trials (n = 2602; 66.5%). Cephalosporins were the most frequent antibiotics studied in trials (22/30, 73.3%). Only a few antibiotics active against resistant UTIs have been tested in randomised clinical trials, mainly aminoglycosides. The average point cure rate of all investigational drugs was estimated to 95.3% (95% CI 93.5-96.9%). Among 3002 patients for whom cure and failure rates were reported, only 3.9% (3.9%; 118/3002) were considered clinically to have treatment failure, while 135 (4.5%; 135/3002) had microbiological failure.

CONCLUSIONS

We observed high treatment cure rates, regardless of the investigational drug chosen, the route of administration, duration and dosing. This suggests that future research should prioritise observational studies and clinical trials on children with multi-drug-resistant infections.

Multidrug-resistant Gram-negative Bacterial Bloodstream Infections in Children's Hospitals in Japan, 2010-2017

BACKGROUND

The risk factors of multidrug-resistant (MDR) Gram-negative bacilli (GNB) bloodstream infection (BSI) are not yet known in children. Our aim was to evaluate risk factors and outcomes associated with MDR GNB BSI in children.

METHODS

Patients with GNB BSI were enrolled between April 2010 and March 2017 at 8 children's hospitals in Japan. Clinical and microbiologic data were collected retrospectively. The risk factors and outcomes of MDR and non-MDR GNB BSI were compared.

RESULTS

In total, 629 GNB BSI episodes met the case definition. The median age and proportion of males were 2 years (interquartile range, 0.3-8.7) and 50.7%, respectively. An underlying disease was found in 94% of patients. The proportion of BSI cases that developed >48 hours after admission was 76.2%. MDR comprised 24.5% of BSI cases. The MDR rate did not change over time (P = 0.540). The effective coverage rate of the initial empiric therapy for the MDR and non-MDR BSI cases was 60.4% and 83.4%, respectively (P < 0.001). The all-cause mortality rate at 28 days for all BSI, MDR-BSI and non-MDR BSI cases was 10.7%, 13.6% and 9.7%, respectively (P = 0.167). MDR BSI was independently associated with cancer chemotherapy within 30 days (odds ratio [OR] 43.90), older age (OR 1.05) and admission to the neonatal ward (OR 0.019).

CONCLUSIONS

One-fourth of GNB BSI cases were MDR. Cancer chemotherapy and older age were risk factors for MDR GNB BSI in children's hospitals. MDR did not increase the all-cause mortality rate.

Antibiotic treatment and antimicrobial resistance in children with urinary tract infections

OBJECTIVES

The aim of this study was to describe antibiotic prescribing patterns and antimicrobial resistance rates in hospitalised children with febrile and afebrile urinary tract infections (UTIs).

METHODS

Antibiotic prescriptions and antibiograms for neonates, infants and older children with UTI admitted to a general district hospital in Central Greece were evaluated. Data covering a 5-year period were collected retrospectively from the Paediatric Department's Electronic Clinical Archive. Patients were included based on clinical and microbiological criteria. Antimicrobial susceptibility was determined by the Kirby-Bauer disk diffusion method.

RESULTS

A total of 230 patients were included in the study. Among 459 prescriptions identified, amikacin (31.2%) was the most common antibiotic prescribed in this population, followed by amoxicillin/clavulanic acid (17.4%) and ampicillin (13.5%). Children received prolonged intravenous (i.v.) treatments for febrile (mean ± S.D., 5.4 ± 1.45 days) and afebrile UTIs (mean ± S.D., 4.4 ± 1.64 days). A total of 236 pathogens were isolated. The main causative organism was Escherichia coli (79.2%) with high reported resistance rates to ampicillin (42.0%), trimethoprim/sulfamethoxazole (26.5%) and amoxicillin/clavulanic acid (12.2%); lower resistance rates were identified for third-generation cephalosporins (1.7%), nitrofurantoin (2.3%), ciprofloxacin (1.4%) and amikacin (0.9%). Klebsiella spp. isolates were highly resistant to cefaclor (27.3%).

CONCLUSION

High prescribing rates for amikacin and penicillins (± β-lactamase inhibitors) and prolonged i.v. treatments were observed. Escherichia coli was highly resistant to ampicillin, whilst third-generation cephalosporins exhibited greater in vitro efficacy. Establishment of antimicrobial stewardship programmes and regular monitoring of antimicrobial resistance could help to minimise inappropriate prescribing for UTIs.

Dissemination of genetically diverse NDM-1, -5, -7 producing-Gram-negative pathogens isolated from pediatric patients in Pakistan

Aim: To determine the prevalence of New Delhi metallo-β-lactamase (NDM)-producing Gram-negative pathogens isolated from children's samples. Materials & methods: Carbapenem-resistant clinical isolates (n = 117) were confirmed by VITEK^® 2 compact system, matrix-assisted laser desorption ionization-time of flight and multilocus sequence typing. MIC (μg/ml) of various antibiotics was determined by VITEK 2 compact system. Molecular characterization of the isolates was performed by PCR, DNA sequencing, PFGE and DNA hybridization. Results: Out of 117 carbapenemase producers, 37 (31.6%) and 29 (24.7%) were Klebsiella pneumoniae and Acinetobacter baumannii, respectively. 72 (61.5%) isolates were NDM positive and among these 60, 9 and 3 were NDM-1, -5 and -7, respectively. Majority of the NDM-producing K. pneumoniae belonged to ST11 and ST273 while most of the Escherichia coli belonged to ST405 and ST101. bla_NDM were mainly located on 150kb plasmids. MIC displayed high resistance against β-lactams drugs including carbapenems, and the most sensitive drugs were tigecycline and colistin. Conclusion: Dissemination of bla_NDM-producing pathogens, particularly in children clinical settings, is a matter of great public health concern.

A Multi-Centered Case-Case-Control Study of Factors Associated With Klebsiella pneumoniae Carbapenemase-Producing Enterobacteriaceae Infections in Children and Young Adults

BACKGROUND

Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae (KPC-CRE) are multidrug-resistant organisms causing morbidity and mortality worldwide. KPC-CRE prevalence is increasing in pediatric populations, though multi-centered data are lacking. Identifying risk factors for KPC-CRE infection in children and classifying genotypes is a priority in this vulnerable population.

METHODS

A case-case-control study of patients (0-22 years) at 3 tertiary-care Chicago-area medical centers, 2008-2015, was conducted. Case group 1 children possessed KPC-CRE infections; case group 2 harbored carbapenem-susceptible Enterobacteriaceae (CSE) infections; controls had negative cultures. Case-control matching was 1:1:3 by age, infection site and hospital. Statistical and molecular analyses were performed.

RESULTS

Eighteen KPC-CRE infections were identified; median patient age was 16.5 years. Of 4 available KPC-CRE, 2 were unrelated, non-ST258 KP strains harboring blaKPC-2, one was a ST258 KP harboring blaKPC-3, and the last was an E. coli containing blaKPC-2. KPC-CRE and CSE-infected patients had more multidrug-resistant organisms infections, long-term care facility admissions and lengths of stay (LOS) > 7 days before culture. KPC-CRE and CSE patients had more gastrointestinal comorbidities (odds ratios [Ors], 28.0 and 6.4) and ≥ 3 comorbidities (Or 15.4 and 3.5) compared with controls; KPC-CRE patients had significantly more pulmonary and neurologic comorbidities (both ORs 4.4) or GI and pulmonary devices (ORs, 11.4 and 6.1). Compared with controls, CSE patients had more prior fluoroquinolone use (OR, 7.4); KPC-CRE patients had more carbapenem or aminoglycoside use (ORs, 10.0 and 8.0). Race, gender, LOS and mortality differences were insignificant.

CONCLUSIONS

Pediatric patients with KPC-CRE infection suffer from high multi-system disease/device burdens and exposures to carbapenems and aminoglycosides. Different from adult reports, non-ST258 KP strains were more common, and LOS and mortality rates were similar in all groups. Pediatric CRE control in should focus on modifiable risk factors including antibiotic and device utilization.

Increased Mortality Among Carbapenemase-Producing Carbapenem-Resistant Enterobacteriaceae Carriers Who Developed Clinical Isolates of Another Genotype

Background

Carbapenemase production by carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) is encoded by a variety of genes on mobile genetic elements. Patients colonized by 1 genotype of CP-CRE may be subsequently infected by another genotype of CP-CRE. We sought to determine whether CP-CRE carriers who developed infection with another genotype had a higher mortality risk.

Methods

A retrospective cohort study was conducted using collected data from January 2012 to December 2016. Clinical isolates of CP-CRE were analyzed among the CP-CRE carriers who had developed an infection during their stay in the hospital. Comparison was made between CP-CRE carriers who developed clinical isolates of another genotype and those whose clinical isolates were of the same CP-CRE genotype that they were originally colonized with. The primary outcome analyzed was the 14-day mortality rate.

Results

A total of 73 CP-CRE carriers who had developed infection were analyzed. Ten (15.4%) of the carriers who developed an infection with clinical isolates of the same CP-CRE genotype died within 14 days, whereas 5 (62.5%) of those who developed an infection with clinical isolates of a different genotype died. This represented a 6-fold increase (adjusted relative risk, 6.36; 95% confidence interval, 1.75-23.06; P = .005) in the 14-day mortality rate.

Conclusions

CP-CRE carriers who developed clinical isolates of another genotype are at risk of increased mortality. This is a novel finding that is of interest to health care organizations worldwide, with profound implications for infection control measures, such as patient and staff cohorting.

Future Challenges in Pediatric and Neonatal Sepsis: Emerging Pathogens and Antimicrobial Resistance

The incidence of severe infections caused by multidrug-resistant (MDR) pathogens is currently rising worldwide, and increasing numbers of neonates and children with serious bloodstream infections due to resistant bacteria are being reported. Severe sepsis and septic shock due to gram-negative bacteria represent a significant cause of morbidity and mortality, and contribute to high health care costs. Antimicrobial resistance among Enterobacteriaceae represents a major problem in both health care-associated and community-acquired infections, with extended-spectrum β-lactamases (ESBLs) and carbapenem-resistant Enterobacteriaceae (CRE) now presenting the main threat. These infections in adult populations have been associated with poor clinical outcomes, but very limited data have been published so far about risk factors and clinical outcome of ESBL-associated and CRE sepsis in the pediatric population. The treatment of these infections in neonates and children is particularly challenging due to the limited number of available effective antimicrobials. Evidence-based use of new and older antibiotics based on both strategic and regulatory clinical trials is paramount to improve management of these severe infections in neonates and children.

Use of Colistin in Critically Ill Patients

Due to lack of better therapeutic options, colistin use for extensively drug-resistant Gram-negative organisms was revived in the past two decades, including in patients in intensive-care units (ICU). There are multiple knowledge gaps pertaining to the clinical use and utility of colistin in critically-ill patients, but due to lack of options, it is used in these high risk patients. In this chapter, we critically review the various topics pertaining to colistin use in critically-ill patients, while highlighting the (lack of) controlled evidence supporting common current practices pertaining to colistin use by clinicians.

The use of polymyxins to treat carbapenem resistant infections in neonates and children

INTRODUCTION

The incidence of healthcare-associated multidrug resistant bacterial infections, particularly due to carbapenem resistant organisms, has been on the rise globally. Among these are the carbapenem resistant Acinetobacter baumannii and Enterobacteriaceae, which have been responsible for numerous outbreaks in neonatal units. The polymyxins (colistin and polymyxin B) are considered to be the last resort antibiotics for treating such infections. However, pharmacokinetic and pharmacodynamic data on the use of polymyxins in neonates and children are very limited, and there are safety concerns.

AREAS COVERED

In this review, the authors summarize the global burden of multidrug resistance, particularly carbapenem resistance, in the neonatal and paediatric population, and the potential wider use of polymyxins in treating these infections.

EXPERT OPINION

Both colistin and polymyxin B have similar efficacy in treating multidrug resistant infections but have safety concerns. However, polymyxin B appears to be a better therapeutic option, with more rapid and higher steady state concentrations achieved compared to colistin and less reported nephrotoxicity. There is virtually no data in neonates and children currently; there is therefore an urgent need for pharmacokinetic and safety trials in these populations to determine the optimal drug and dosing regimens and provide recommendations for their use against carbapenem resistant infections.

Characteristics of NDM-1-producing Klebsiella pneumoniae ST234 and ST1412 isolates spread in a neonatal unit

BACKGROUND

The emergence of carbapenem-resistant Klebsiella pneumoniae (CR-KP) has become a significant problem worldwide and also being a major threat to children and newborns. Here we report an outbreak of NDM-1-producing K. pneumoniae in a neonatal unit.

RESULTS

Six CR-KP strains, isolated from neonates with symptoms of infection, were identified using a VITEK-2 compact system, and the clinical data were retrieved from the electronic case records. In vitro susceptibility testing with broth dilution method showed that all six K. pneumoniae isolates were resistant to carbapenems and susceptible to colistin, aminoglycosides, fluoroquinolones and tigecycline. Based on the polymerase chain reaction results, each isolate was found to be blaNDM-1 gene positive. Clonal relationships were analysed using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) and showed that two different PFGE patterns were formed, which belonged to sequence types ST234 and ST1412. Plasmids carrying blaNDM-1 were successfully transferred from four of the six isolates to an Escherichia coli recipient through conjugative assays. S1-PFGE and Southern blot hybridization showed that four NDM-1-producing K. pneumoniae were clonal and carried blaNDM-1 on the same plasmid. The outbreak was effectively controlled by reducing the potential infection sources. All the patients were successfully treated and recovered after receiving an increased dose of carbapenems. Although the source of this outbreak was not clear, comprehensive measures were carried out and the outbreak was effectively controlled.

CONCLUSIONS

ST234 and ST1412 of NDM-1-producing Klebsiella pneumoniae are the resistant clone spread in the neonatal unit, comprehensive infection control measures and optimized carbapenem therapy played an important role in controlling this NDM-1-producing K. pneumoniae outbreak.