Antibiotic Susceptibility of Escherichia coli Among Infants Admitted to Neonatal Intensive Care Units Across the US From 2009 to 2017

Antibiotic Stewardship in the Neonatal Intensive Care Unit

Antibiotic stewardship is a multidisciplinary, evidence-based approach to optimize antibiotic use and mitigate development of antibiotic resistance. Neonates have high rates of antibiotic exposure, particularly those born preterm and admitted to the NICU, and mounting evidence describes the adverse consequences of such exposures in the absence of infection. Here, we review the general principles of antibiotic stewardship and how they can be applied in NICUs. The unique characteristics of NICUs and patients cared for in this setting, which warrant unique implementation strategies and special considerations are discussed. We summarize current antibiotic use metrics for assessment of responses to stewardship interventions and changes over time, and review evidence-based infection prevention practices in the NICU. Current recommendations for empiric antibiotic use in the NICU and the utility of infection biomarkers are summarized. Lastly, given the growing global threat of increasing antibiotic resistance, specific threats in the NICU are highlighted.

[A cross-sectional study on the pathogen composition and antimicrobial resistance in neonates with sepsis in Hebei Province, China]

OBJECTIVES

To study the pathogen composition and antimicrobial resistance characteristics in neonates with sepsis in the Hebei area, providing a basis for optimizing the management strategies for neonatal sepsis in the region.

METHODS

The medical data of neonates with sepsis confirmed by blood culture from 23 hospitals in Hebei Province were collected prospectively from November 1, 2021 to December 31, 2022. The pathogen composition and antimicrobial resistance characteristics were analyzed in early-onset sepsis (EOS), community-acquired late-onset sepsis (CALOS), and hospital-acquired late-onset sepsis (HALOS) cases.

RESULTS

A total of 289 neonates were included, accounting for 292 infection episodes, with 117 (40.1%) EOS, 95 (32.5%) CALOS, and 80 (27.4%) HALOS cases. A total of 294 pathogens were isolated, with 118 (40.1%) from the EOS group, where Escherichia coli (39 strains, 33.0%) and coagulase-negative staphylococci (13 strains, 11.0%) were the most common. In the CALOS group, 95 pathogens were isolated (32.3%), with Escherichia coli (35 strains, 36.8%) and group B Streptococcus (14 strains, 14.7%) being predominant. The HALOS group yielded 81 isolates (27.6%), with Klebsiella pneumoniae (24 strains, 29.6%) and Escherichia coli (21 strains, 25.9%) as the most frequent. Coagulase-negative staphylococci showed over 80% resistance to penicillin antibiotics. Escherichia coli and Klebsiella pneumoniae showed a resistance rate of 2.2% to 75.0% to common β-lactam antibiotics. The resistance rates of predominant Gram-negative bacteria in the HALOS group to common β-lactam antibiotics were higher than those in the CALOS group.

CONCLUSIONS

In the Hebei region, Escherichia coli is the most common pathogen in both EOS and LOS. There are differences in the composition and antimicrobial resistance of pathogens among different types of neonatal sepsis. The choice of empirical antimicrobial drugs should be based on the latest surveillance data from the region.

Genomic surveillance for antimicrobial resistance - a One Health perspective

Antimicrobial resistance (AMR) - the ability of microorganisms to adapt and survive under diverse chemical selection pressures - is influenced by complex interactions between humans, companion and food-producing animals, wildlife, insects and the environment. To understand and manage the threat posed to health (human, animal, plant and environmental) and security (food and water security and biosecurity), a multifaceted 'One Health' approach to AMR surveillance is required. Genomic technologies have enabled monitoring of the mobilization, persistence and abundance of AMR genes and mutations within and between microbial populations. Their adoption has also allowed source-tracing of AMR pathogens and modelling of AMR evolution and transmission. Here, we highlight recent advances in genomic AMR surveillance and the relative strengths of different technologies for AMR surveillance and research. We showcase recent insights derived from One Health genomic surveillance and consider the challenges to broader adoption both in developed and in lower- and middle-income countries.

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.

Ampicillin and Gentamicin Treatment for Early Onset Neonatal Sepsis: When One Size Does Not Fit All

Based on in vitro susceptibilities and the concern for emergence of resistance and long-term safety, ampicillin plus gentamicin remains the recommended antibiotic regimen for early onset neonatal sepsis. Our objective was to identify potential limitations of this regimen based on clinical and pathogen characteristics while minimizing risks associated with prolonged antibiotic exposure. We identified 43 gram-negative pathogens in 42 patients. Escherichia coli (E coli) occurred in 50% and Streptococcus agalactiae in 23.8% of patient. Ampicillin resistance was common, particularly in E coli (85.7%). Mortality was 23.8%, all due to E coli. We found that E coli is the most frequent pathogen and has a high mortality particularly in neonates < 1500 g; mortality is high with the current dosing strategy when E coli is resistant to ampicillin even when sensitive to gentamicin; resistance to gentamicin remains low but seems to be increasing while resistance to third-generation cephalosporins remains very low.

Prevalence of gram-negative bacteria and their antibiotic resistance in neonatal sepsis in Iran: a systematic review and meta-analysis

BACKGROUND

Neonatal sepsis, particularly gram-negative (GN) bacteria-induced, is a significant cause of morbidity and mortality in newborns. Healthcare professionals find this issue challenging because of antibiotic resistance. This study aims to combine findings to identify the prevalence of GN bacteria and their antibiotic resistance in Iranian neonates with sepsis.

METHODS

This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The literature search was performed through international databases, including (PubMed/MEDLINE, EMBASE, Scopus, and Web of Science), Iranian local databases (Magiran, Iranmedex, Irandoc, Scimed, and SID), and the first 100 records of Google Scholar. Analytical cross-sectional study checklist from the Joanna Briggs Institute (JBI) was used for the quality assessment of included studies. Comprehensive Meta-Analysis Software Version 2 was used to conduct the meta-analysis. The between-study heterogeneity was investigated by I2 statistics.

RESULTS

The prevalence of GN bacteria was estimated to be 53.6% [95% CI: 45.9- 61.1: P = 0.362] in Iranian neonates with sepsis, based on 31 studies with a sample size of 104,566. klebsiella pneumoniae (K.pneumonia) (23.2% [95% CI: 17.5-30.0, P < 0.001]) followed by Escherichia coli (E.coli) (13.5% [95% CI: 9.4-18.9, P < 0.001]) were more prevalent among GN bacteria. The highest resistance in K.pneumoniae was observed in Cefixime (80.6%, [95% CI: 56.3-93.1, P = 0.018]). E.coli showed greater resistance to Ampicillin (61.8%, [95% CI: 44.2-76.5, P = 0.188]. The prevalence of GN bacteria in Iranian neonates with sepsis has a decreasing trend based on the year, as shown by a meta-regression model (P < 0.0004).

CONCLUSION

GN pathogens, particularly K.pneumoniae, and E.coli, are the leading cause of neonatal sepsis in Iran. GN bacteria showed the highest resistance to Third-generation cephalosporin and Aminoglycosides.

New Antimicrobials for the Treatment of Neonatal Sepsis Caused by Multi-Drug-Resistant Bacteria: A Systematic Review

BACKGROUND

Infections by multi-drug-resistant (MDR) organisms are sharply increasing in newborns worldwide. In low and middle-income countries, a disproportionate amount of neonatal sepsis caused by MDR Gram negatives was recently reported. Newborns with infections by MDR organisms with limited treatment options may benefit from novel antimicrobials.

METHODS

We performed a literature search investigating the use in newborns, infants and children of novel antimicrobials for the treatment of MDR Gram negatives, namely ceftazidime/avibactam, ceftolozane/tazobactam, cefiderocol, meropenem/vaborbactam, imipenem/relebactam, and Gram positives with resistance of concern, namely ceftaroline and dalbavancin. PubMed, EMBASE, and Web of Science were searched.

RESULTS

A total of 50 records fulfilled the inclusion criteria. Most articles were case reports or case series, and ceftazidime/avibactam was the most studied agent. All studies showed favorable efficacy and safety profile in newborns and across different age cohorts.

CONCLUSIONS

novel antibiotics may be considered in newborns for the treatment of MDR Gram negatives with limited treatment options and for Gram positives with resistance concerns. Further studies are needed to address their effectiveness and safety in newborns.

Antibiotic susceptibility of Escherichia coli isolated from neonates admitted to neonatal intensive care units across China from 2015 to 2020

Background

Escherichia coli is one of the most common pathogens causing neonatal infections. Recently, the incidence and drug resistance of E. coli have increased, posing a major threat to neonatal health. The aim of this study was to describe and analyze the antibiotic resistance and multilocus sequence typing (MLST) characteristics of E. coli derived from infants admitted to neonatal intensive care units (NICUs) across China.

Methods

In this study, 370 strains of E. coli from neonates were collected. E. coli isolated from these specimens were subjected to antimicrobial susceptibility testing (by broth microdilution method) and MLST.

Results

The overall resistance rate was 82.68%, with the highest rate of methicillin/sulfamethoxazole (55.68%) followed by cefotaxime (46.22%). Multiple resistance rate was 36.74%, 132 strains (35.68%) had extended-spectrum β-lactamase (ESBL) phenotype and 5 strains (1.35%) had insensitivity to the tested carbapenem antibiotics. The resistance of E. coli isolated from different pathogenicity and different sites of infections varied, strains derived from sputum were significantly more resistant to β-lactams and tetracyclines. Currently, the prevalence spectrum in NICUs was dominated by ST1193, ST95, ST73, ST69 and ST131 across China. And the multidrug resistance of ST410 was the most severe. ST410 had the highest resistance rate to cefotaxime (86.67%), and its most common multidrug resistance pattern was β-lactams + aminoglycosides + quinolones + tetracyclines + sulfonamides.

Conclusions

Substantial proportions of neonatal E. coli isolates were severely resistant to commonly administered antibiotics. MLST results can suggest the prevalent characteristics of antibiotic resistance in E. coli with different ST types.

Burnham CA, Warner BB, Tarr PI, Dantas G. Gut pathogen colonization precedes bloodstream infection in the neonatal intensive care unit

Bacterial bloodstream infections (BSIs) resulting in late-onset sepsis affect up to half of extremely preterm infants and have substantial morbidity and mortality. Bacterial species associated with BSIs in neonatal intensive care units (NICUs) commonly colonize the preterm infant gut microbiome. Accordingly, we hypothesized that the gut microbiome is a reservoir of BSI-causing pathogenic strains that increase in abundance before BSI onset. We analyzed 550 previously published fecal metagenomes from 115 hospitalized neonates and found that recent ampicillin, gentamicin, or vancomycin exposure was associated with increased abundance of Enterobacteriaceae and Enterococcaceae in infant guts. We then performed shotgun metagenomic sequencing on 462 longitudinal fecal samples from 19 preterm infants (cases) with BSI and 37 non-BSI controls, along with whole-genome sequencing of the BSI isolates. Infants with BSI caused by Enterobacteriaceae were more likely than infants with BSI caused by other organisms to have had ampicillin, gentamicin, or vancomycin exposure in the 10 days before BSI. Relative to controls, gut microbiomes of cases had increased relative abundance of the BSI-causing species and clustered by Bray-Curtis dissimilarity according to BSI pathogen. We demonstrated that 11 of 19 (58%) of gut microbiomes before BSI, and 15 of 19 (79%) of gut microbiomes at any time, harbored the BSI isolate with fewer than 20 genomic substitutions. Last, BSI strains from the Enterobacteriaceae and Enterococcaceae families were detected in multiple infants, indicating BSI-strain transmission. Our findings support future studies to evaluate BSI risk prediction strategies based on gut microbiome abundance in hospitalized preterm infants.

Group B Streptococcus in Pregnancy

To decrease risk of early-onset neonatal sepsis from group B streptococcus (GBS), pregnant patients should undergo screening between 36 0/7 and 37 6/7 weeks' gestation. Patients with a positive vaginal-rectal culture, GBS bacteriuria , or history of newborn with GBS disease should receive intrapartum antibiotic prophylaxis (IAP) with an agent targeting GBS. If GBS status is unknown at time of labor, IAP should be administered in cases of preterm birth, rupture of membranes for >18 hours, or intrapartum fever. The antibiotic of choice is intravenous penicillin; alternatives should be considered in cases of penicillin allergy depending on allergy severity.

Bloodstream Infection Due to a VIM-Metallo-β-Lactamase-Producing Klebsiella pneumoniae Treated with Cefiderocol in a Preterm Newborn

BACKGROUND

The prevalence of certain multidrug-resistant organisms (MDROs), especially Gram-negative bacteria, is dramatically increasing in patient care settings, including pediatric and neonatal units. However, most of the new drugs available for the treatment of MDROs have not yet been studied in children and newborns.

CASE REPORT

We report the clinical case of a preterm neonate, born at 31 weeks gestation + 1 day of age by emergency Cesarean Section (CS), with a bloodstream infection (BSI) due to a Verona integron-borne metallo-β-lactamase (VIM)-producing Klebsiella pneumoniae. We successfully treated the infection with cefiderocol in an off-label regimen at the following dose: loading dose 60 mg/kg and then 40 mg/kg every 8 h in extended infusion for 9 days. The baby showed a quick clinical and biochemical improvement and tolerated well the treatment. Follow-up blood cultures at 48 h after the start of cefiderocol were negative.

CONCLUSIONS

Antimicrobial-resistant pathogens are of increasing concern in neonatal settings. More studies in this unique population are necessary to better describe the pharmacokinetic and pharmacodynamic profile of the new drugs against MDROs, such as cefiderocol, and to define a proper effective dose.

Late-Onset Sepsis Among Very Preterm Infants

OBJECTIVES

To determine the epidemiology, microbiology, and associated outcomes of late-onset sepsis among very preterm infants using a large and nationally representative cohort of NICUs across the United States.

METHODS

Prospective observational study of very preterm infants born 401 to 1500 g and/or 22 to 29 weeks' gestational age (GA) from January 1, 2018, to December 31, 2020, who survived >3 days in 774 participating Vermont Oxford Network centers. Late-onset sepsis was defined as isolation of a pathogenic bacteria from blood and/or cerebrospinal fluid, or fungi from blood, obtained >3 days after birth. Demographics, clinical characteristics, and outcomes were compared between infants with and without late-onset sepsis.

RESULTS

Of 118 650 infants, 10 501 (8.9%) had late-onset sepsis for an incidence rate of 88.5 per 1000 (99% confidence interval [CI] [86.4-90.7]). Incidence was highest for infants born ≤23 weeks GA (322.0 per 1000, 99% CI [306.3-338.1]). The most common pathogens were coagulase negative staphylococci (29.3%) and Staphylococcus aureus (23.0%), but 34 different pathogens were identified. Infected infants had lower survival (adjusted risk ratio [aRR] 0.89, 95% CI [0.87-0.90]) and increased risks of home oxygen (aRR 1.32, 95% CI [1.26-1.38]), tracheostomy (aRR 2.88, 95% CI [2.47-3.37]), and gastrostomy (aRR 2.09, 95% CI [1.93-2.57]) among survivors.

CONCLUSIONS

A substantial proportion of very preterm infants continue to suffer late-onset sepsis, particularly those born at the lowest GAs. Infected infants had higher mortality, and survivors had increased risks of technology-dependent chronic morbidities. The persistent burden and diverse microbiology of late-onset sepsis among very preterm infants underscore the need for innovative and potentially organism-specific prevention strategies.

Neonatal Early-Onset Sepsis

Early-onset sepsis (EOS) is a significant cause of morbidity and mortality among newborn infants, particularly among those born premature. The epidemiology of EOS is changing over time. Here, we highlight the most contemporary data informing the epidemiology of neonatal EOS, including incidence, microbiology, risk factors, and associated outcomes, with a focus on infants born in high-income countries during their birth hospitalization. We discuss approaches to risk assessment for EOS, summarizing national guidelines and comparing key differences between approaches for term and preterm infants. Lastly, we analyze contemporary antibiotic resistance data for EOS pathogens to inform optimal empiric treatment for EOS.

Escherichia coli Is Overtaking Group B Streptococcus in Early-Onset Neonatal Sepsis

The widespread use of intrapartum antibiotic prophylaxis (IAP) to prevent group B streptococcus (GBS) early-onset sepsis (EOS) is changing the epidemiology of EOS. Italian prospective area-based surveillance data (from 1 January 2016 to 31 December 2020) were used, from which we identified 64 cases of culture-proven EOS (E. coli, n = 39; GBS, n = 25) among 159,898 live births (annual incidence rates of 0.24 and 0.16 per 1000, respectively). Approximately 10% of E. coli isolates were resistant to both gentamicin and ampicillin. Five neonates died; among them, four were born very pre-term (E. coli, n = 3; GBS, n = 1) and one was born full-term (E. coli, n = 1). After adjustment for gestational age, IAP-exposed neonates had ≥95% lower risk of death, as compared to IAP-unexposed neonates, both in the whole cohort (OR 0.04, 95% CI 0.00–0.70; p = 0.03) and in the E. coli EOS cohort (OR 0.05, 95% CI 0.00–0.88; p = 0.04). In multi-variable logistic regression analysis, IAP was inversely associated with severe disease (OR = 0.12, 95% CI 0.02–0.76; p = 0.03). E. coli is now the leading pathogen in neonatal EOS, and its incidence is close to that of GBS in full-term neonates. IAP reduces the risk of severe disease and death. Importantly, approximately 10% of E. coli isolates causing EOS were found to be resistant to typical first-line antibiotics.

Antimicrobial Susceptibility Profiles Among Neonatal Early-onset Sepsis Pathogens

BACKGROUND

Empiric administration of ampicillin and gentamicin is recommended for newborns at risk of early-onset sepsis (EOS). There are limited data on antimicrobial susceptibility of all EOS pathogens.

METHODS

Retrospective review of antimicrobial susceptibility data from a prospective EOS surveillance study of infants born ≥22 weeks' gestation and cared for in Neonatal Research Network centers April 2015-March 2017. Nonsusceptible was defined as intermediate or resistant on final result.

RESULTS

We identified 239 pathogens (235 bacteria, 4 fungi) in 235 EOS cases among 217,480 live-born infants. Antimicrobial susceptibility data were available for 189/239 (79.1%) isolates. Among 81 Gram-positive isolates with ampicillin and gentamicin susceptibility data, all were susceptible in vitro to either ampicillin or gentamicin. Among Gram-negative isolates with ampicillin and gentamicin susceptibility data, 72/94 (76.6%) isolates were nonsusceptible to ampicillin, 8/94 (8.5%) were nonsusceptible to gentamicin, and 7/96 (7.3%) isolates were nonsusceptible to both. Five percent or less of tested Gram-negative isolates were nonsusceptible to each of third or fourth generation cephalosporins, piperacillin-tazobactam, and carbapenems. Overall, we estimated that 8% of EOS cases were caused by isolates nonsusceptible to both ampicillin and gentamicin; these were most likely to occur among preterm, very-low birth weight infants.

CONCLUSIONS

The vast majority of contemporary EOS pathogens are susceptible to the combination of ampicillin and gentamicin. Clinicians may consider the addition of broader-spectrum therapy among newborns at highest risk of EOS, but we caution that neither the substitution nor the addition of 1 single antimicrobial agent is likely to provide adequate empiric therapy in all cases.

Neonatal multidrug-resistant gram-negative infection: epidemiology, mechanisms of resistance, and management

Infants admitted to the neonatal intensive care unit, particularly those born preterm, are at high risk for infection due to the combination of an immature immune system, prolonged hospitalization, and frequent use of invasive devices. Emerging evidence suggests that multidrug-resistant gram-negative (MDR-GN) infections are increasing in neonatal settings, which directly threatens recent and ongoing advances in contemporary neonatal care. A rising prevalence of antibiotic resistance among common neonatal pathogens compounds the challenge of optimal management of suspected and confirmed neonatal infection. We review the epidemiology of MDR-GN infections in neonates in the United States and internationally, with a focus on extended-spectrum β-lactamase (ESBL)-producing Enterobacterales and carbapenem-resistant Enterobacterales (CRE). We include published single-center studies, neonatal collaborative reports, and national surveillance data. Risk factors for and mechanisms of resistance are discussed. In addition, we discuss current recommendations for empiric antibiotic therapy for suspected infections, as well as definitive treatment options for key MDR organisms. Finally, we review best practices for prevention and identify current knowledge gaps and areas for future research. IMPACT: Surveillance and prevention of MDR-GN infections is a pediatric research priority. A rising prevalence of MDR-GN neonatal infections, specifically ESBL-producing Enterobacterales and CRE, compounds the challenge of optimal management of suspected and confirmed neonatal infection. Future studies are needed to understand the impacts of MDR-GN infection on neonatal morbidity and mortality, and studies of current and novel antibiotic therapies should include a focus on the pharmacokinetics of such agents among neonates.

Molecular epidemiology and antimicrobial resistance phenotype of paediatric bloodstream infections caused by Gram-negative bacteria

Background

Gram-negative organisms are common causes of bloodstream infection (BSI) during the neonatal period and early childhood. Whilst several large studies have characterised these isolates in adults, equivalent data (particularly incorporating whole genome sequencing) is lacking in the paediatric population.

Methods

We perform an epidemiological and sequencing based analysis of Gram-negative bloodstream infections (327 isolates (296 successfully sequenced) from 287 patients) in children <18 years old between 2008 and 2018 in Oxfordshire, UK.

Results

Here we show that the burden of infection lies predominantly in neonates and that most infections are caused by Escherichia coli, Klebsiella spp. and Enterobacter hormaechei. There is no evidence in our setting that the proportion of antimicrobial resistant isolates is increasing in the paediatric population although we identify some evidence of sub-breakpoint increases in gentamicin resistance. The population structure of E. coli BSI isolates in neonates and children mirrors that in adults with a predominance of STs 131/95/73/69 and the same proportions of O-antigen serotypes. In most cases in our setting there is no evidence of transmission/point-source acquisition and we demonstrate the utility of whole genome sequencing to refute a previously suspected outbreak.

Conclusions

Our findings support continued use of current empirical treatment guidelines and suggest that O-antigen targeted vaccines may have a role in reducing the incidence of neonatal sepsis.

Whole-genome sequencing-based phylogeny, antibiotic resistance, and invasive phenotype of Escherichia coli strains colonizing the cervix of women in preterm labor

Background

Escherichia coli is a major neonatal pathogen and the leading cause of early-onset sepsis in preterm newborns. Maternal E. coli strains are transmitted to the newborn causing invasive neonatal disease. However, there is a lack of data regarding the phenotypic and genotypic characterization of E. coli strains colonizing pregnant women during labor.

Methods

This prospective study performed at the University of Oklahoma Medical Center (OUHSC) from March 2014 to December 2015, aimed to investigate the colonization rate, and the phylogeny, antibiotic resistance traits, and invasive properties of E. coli strains colonizing the cervix of fifty pregnant women diagnosed with preterm labor (PTL). Molecular analyses including bacterial whole-genome sequencing (WGS), were performed to examine phylogenetic relationships among the colonizing strains and compare them with WGS data of representative invasive neonatal E. coli isolates. Phenotypic and genotypic antibiotic resistance traits were investigated. The bacteria’s ability to invade epithelial cells in vitro was determined.

Results

We recruited fifty women in PTL. Cervical samples yielded E. coli in 12 % (n=6). The mean gestational age was 32.5 (SD±3.19) weeks. None delivered an infant with E. coli disease. Phenotypic and genotypic antibiotic resistance testing did not overall demonstrate extensive drug resistance traits among the cervical E. coli isolates, however, one isolate was multi-drug resistant. The isolates belonged to five different phylogroups, and WGS analyses assigned each to individual multi-locus sequence types. Single nucleotide polymorphism-based comparisons of cervical E. coli strains with six representative neonatal E. coli bacteremia isolates demonstrated that only half of the cervical E. coli isolates were phylogenetically related to these neonatal invasive strains. Moreover, WGS comparisons showed that each cervical E. coli isolate had distinct genomic regions that were not shared with neonatal E. coli isolates. Cervical and neonatal E. coli isolates that were most closely related at the phylogenetic level had similar invasion capacity into intestinal epithelial cells. In contrast, phylogenetically dissimilar cervical E. coli strains were the least invasive among all isolates.

Conclusions

This pilot study showed that a minority of women in PTL were colonized in the cervix with E. coli, and colonizing strains were not phylogenetically uniformly representative of E. coli strains that commonly cause invasive disease in newborns. Larger studies are needed to determine the molecular characteristics of E. coli strains colonizing pregnant women associated with an increased risk of neonatal septicemia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02389-7.

Early-Onset Sepsis Among Very Preterm Infants

OBJECTIVES

To determine the epidemiology and microbiology of early-onset sepsis (EOS) among very preterm infants using a nationally representative cohort from academic and community hospitals to inform empirical antibiotic guidance, highlight risk factors for infection, and aid in prognostication for infected infants.

METHODS

Prospective observational study of very preterm infants born weighing 401 to 1500 g or at 22 to 29 weeks' gestational age from January 2018 to December 2019 in 753 Vermont Oxford Network centers. EOS was defined as a culture-confirmed bacterial infection of the blood or cerebrospinal fluid in the 3 days after birth. Demographics, clinical characteristics, and outcomes were compared between infants with and without EOS.

RESULTS

Of 84 333 included infants, 1139 had EOS for an incidence rate of 13.5 per 1000 very preterm births (99% confidence interval [CI] 12.5-14.6). Escherichia coli (538 of 1158; 46.5%) and group B Streptococcus (218 of 1158; 18.8%) were the most common pathogens. Infected infants had longer lengths of stay (median 92 vs 66 days) and lower rates of survival (67.5% vs 90.4%; adjusted risk ratio 0.82 [95% CI 0.79-0.85]) and of survival without morbidity (26.1% vs 59.4%; adjusted risk ratio 0.66 [95% CI 0.60-0.72]).

CONCLUSIONS

In a nationally representative sample of very preterm infants with EOS from 2018 to 2019, approximately one-third of isolates were neither group B Streptococcus nor E coli. Three-quarters of all infected infants either died or survived with a major medical morbidity. The profoundly negative impact of EOS on very preterm infants highlights the need for novel preventive strategies.

The Term Newborn: Early-Onset Sepsis

The changing epidemiology of early-onset neonatal sepsis among term infants has required reappraisal of approaches to management of newborn infants at potential risk. As this is now a rare disease, new strategies for reduction in diagnostic testing and empirical treatment have been developed. Adoption and refinement of these strategies should be a priority for all facilities where babies are born.

CTX-M-15 Positive Escherichia coli and Klebsiella pneumoniae Outbreak in the Neonatal Intensive Care Unit of a Maternity Hospital in Ha'il, Saudi Arabia

Objective

The aim of this study was to retrospectively characterize E. coli and K. pneumoniae isolates obtained from neonates during a suspected NICU outbreak of infection in Ha’il, Saudi Arabia during a period of one month (April 2014).

Methods

Antibiotic susceptibility patterns, molecular characterization for antibiotic-resistant genes (blaTEM, blaSHV, and blaCTX-M), and genotyping by PFGE and MLST were performed.

Results

A total of 24 E. coli and 48 K. pneumoniae isolates were cultured from neonates that had been admitted to the NICU. Among E. coli, the majority of isolates (19/24) were ESBL-positive and all of these nineteen (100%) harbored the CTX-M-15 gene. A total of 15% (3/19) were co-producers of CTX-M-15 and SHV-12, and 68.4% (13/19) were co-producers of CTX-M-15 and TEM-1. Among K. pneumoniae isolates, 87.5% (42/48) were ESBL positive with 92.85% (39/42) of these isolates containing the CTX-M-15 gene. A total of 97% (38/39) of K. pneumoniae were co-producers of CTX-M-15 and SHV-12, and 88% (37/42) were positive for TEM-1. Furthermore, 85.7% (36/42) K. pneumoniae were co-producers of CTX-M-15 and TEM-1. The majority of E. coli isolates (18/19 isolates) were grouped into two genetic clusters by pulsed field gel electrophoresis (PFGE) and all the isolates were found to be ST-131 type. In contrast, K. pneumoniae (31/42) isolates belonged to a single genotypic lineage, and all (100%) isolates belonged to the ST-14 type.

Conclusion

This is the first report of CTX-M-15-positive, ESBL E. coli, and K. pneumoniae isolates recovered from an outbreak in an NICU in Ha’il, Saudi Arabia. It is alarming to note the high rate of outbreak isolates with simultaneous production of CTX-M-15 and SHV-12 conferring high-level resistance to oxyimino-cephalosporins.

A decade of neonatal sepsis caused by gram-negative bacilli-a retrospective matched cohort study

This study is to determine the incidence and outcome of neonatal gram-negative bacilli (GNB) sepsis in Stockholm, Sweden, and describe bacterial characteristics. This is a retrospective cohort study. All infants with GNB-sepsis between 2006 and 2016 were included and matched with two control groups, with suspected sepsis and uninfected neonates, respectively. Outcome was death before discharge, risk of death within 5 days after sepsis onset, and morbidity. The resistance pattern from all GNB was collected, and all available isolates were subjected to genome typing. All neonates with GNB-sepsis (n = 107) were included, and the cumulative GNB-sepsis incidence was 0.35/1000 live born. The in-hospital mortality was 30/107 (28%). GNB late-onset sepsis (LOS) was associated with an increase in mortality before discharge compared to uninfected controls (OR = 3.9; CI 1.6–9.4) but not versus suspected sepsis. The suspected LOS cases did not statistically differ significantly from uninfected controls. The case fatality rate (CFR) at 5 days was 5/33 (15%) in GNB early-onset sepsis (EOS) and 25/74 (34%) in GNB-LOS. The adjusted hazard for 5 days CFR was higher in GNB-LOS versus uninfected controls (HR = 3.7; CI 1.2–11.2), but no significant difference was seen in GNB-LOS versus suspected sepsis or in suspected sepsis versus controls. ESBL production was seen in 7/107 (6.5%) of the GNB isolates. GNB-LOS was associated with a higher 5 days CFR and in-hospital mortality compared to uninfected controls but not versus suspect sepsis. The incidence of both GNB-EOS and GNB-LOS was lower than previously reported from comparable high-income settings. The occurrence of antibiotic resistance was low.

Early-Onset Sepsis in Neonates - A Population-Based Study in South-West Norway From 1996 to 2018

Background: The epidemiology of early-onset sepsis (EOS) may change over time. Longitudinal surveillance of causative pathogens, antibiotic susceptibility patterns and antibiotic therapy is important for optimal therapy strategies. Objectives: To describe the incidence of culture-confirmed EOS, causative pathogens, antibiotic susceptibility patterns and antibiotic therapy over a 23-year period. Methods: Retrospective population-based study from a single-center neonatal intensive care unit at Stavanger University Hospital, Norway, covering a population in South-West Norway, during the 23-year period 1996-2018. Results: Of 104,377 live born infants, 101 infants (0.97/1,000) had culture-confirmed EOS; 89 with Gram positive and 12 with Gram-negative bacteria. The EOS-attributable mortality was 6/101 (5.8%). For the three most prevalent pathogens the incidences were; Group B streptococcus (GBS) 0.57/1,000, Escherichia coli 0.11/1,000 and viridans group streptococci (VGS) 0.10/1,000. GBS was the most common pathogen (59/93; 63%) in infants with gestational age (GA) ≥ 28 weeks. In contrast, among extremely preterm infants (GA <28 weeks) the incidence of E. coli infection was higher than for GBS infection. The second most common bacterial pathogens causing EOS among term infants were VGS. There was no change in the incidence of EOS for the entire study period, but from 2000 to 2018 there was a mean decline in EOS by 6% per year (95% CI 1%-10%) (p = 0.019). The incidences of GBS and E. coli did not change during the study period. The initial empirical antibiotic regimen for EOS was in all cases a combination of benzylpenicillin or ampicillin and an aminoglycoside, but in 21/101 (21%) of cases a broad-spectrum antibiotic was either added or substituted this regimen. In 2/101 (2%) EOS cases, the pathogens were nonsusceptible to the empirical antibiotic regimen. All E. coli isolates were susceptible to aminoglycosides. Conclusion: GBS was the most common causative pathogens in EOS, but E. coli dominated in infants with GA <28 weeks. There was no change in the incidence of EOS during the entire study period. The current empiric regimen with benzylpenicillin and gentamicin provides a very high coverage for EOS in our setting.

Antibiotic stewardship for early-onset sepsis

Antibiotics are administered to the vast majority of preterm newborns and to a substantial proportion of term infants in the hours after birth due to risk for early-onset sepsis. The approaches taken to determine which newborns should be evaluated for early-onset sepsis, and what type and duration of antibiotics are administered, are important elements of neonatal antibiotic stewardship. The use of multivariate prediction models for sepsis risk assessment among infants born ≥35 weeks' gestation can safely reduce the use of empiric antibiotic therapy. Approaches incorporating serial physical examination may also contribute to decreasing empiric antibiotic exposure among such infants. Among infants born <35 weeks' gestation, delivery characteristics can be used to identify preterm infants at low enough risk of early infection that empiric therapies are not required. Data informing the epidemiology, microbiology and antibiotic susceptibility patterns of early-onset sepsis pathogens can be used to optimize antibiotic choice for empiric and targeted antibiotic therapy to ensure that effective therapies are administered, while decreasing the risks associated with broad-spectrum antibiotic exposure. Optimal use of blood culture and time to positivity data can also contribute to decreasing the risks associated with prolonged antibiotic administration in the face of sterile cultures.