Empiric Antibiotic Use and Susceptibility in Infants With Bacterial Infections: A Multicenter Retrospective Cohort Study

Nucleotide receptors mediate protection against neonatal sepsis and meningitis caused by alpha-hemolysin expressing Escherichia coli K1

Neonatal meningitis-associated Escherichia coli (NMEC) is among the leading causes of bacterial meningitis and sepsis in newborn infants. Several virulence factors have been identified as common among NMEC, and have been shown to play an important role in the development of bacteremia and/or meningitis. However, there is significant variability in virulence factor expression between NMEC isolates, and relatively little research has been done to assess the impact of variable virulence factor expression on immune cell activation and the outcome of infection. Here, we investigated the role of NMEC strain-dependent P2X receptor (P2XR) signaling on the outcome of infection in neonatal mice. We found that alpha-hemolysin (HlyA)-expressing NMEC (HlyA⁺ ) induced robust P2XR-dependent macrophage cell death in vitro, while HlyA^- NMEC did not. P2XR-dependent cell death was inflammasome independent, suggesting an uncoupling of P2XR and inflammasome activation in the context of NMEC infection. In vivo inhibition of P2XRs was associated with increased mortality in neonatal mice infected with HlyA⁺ NMEC, but had no effect on the survival of neonatal mice infected with HlyA^- NMEC. Furthermore, we found that P2XR-dependent protection against HlyA⁺ NMEC in vivo required macrophages, but not neutrophils or NLRP3. Taken together, these data suggest that HlyA⁺ NMEC activates P2XRs which in turn confers macrophage-dependent protection against infection in neonates. In addition, our findings indicate that strain-dependent virulence factor expression should be taken into account when studying the immune response to NMEC.

Analysis of Community-Acquired Urinary Tract Infection Treatment in Pediatric Patients Requiring Hospitalization: Opportunity for Use of Narrower Spectrum Antibiotics

Background: The most narrow-spectrum antibiotic possible should be used for empiric and definitive treatment of pediatric urinary tract infections (UTIs). Objectives: The objectives of this study were to determine an appropriate narrow-spectrum antibiotic for empiric UTI treatment, factors differentiating empiric first-generation cephalosporin (FGC) versus third-generation cephalosporin (TGC) coverage, and factors associated with unnecessarily broad-spectrum definitive antibiotic treatment. Methods: This was a retrospective chart review of children admitted from 2013 to 2015 who were diagnosed with a UTI and received treatment. Multivariable logistic regression assessed independent factors associated with our outcomes. Results: Of 568 diagnosed UTIs, 88.6% received empiric TGC treatment. Empiric coverage among cultured organisms was only 5.4% lower in FGC versus TGC. Adolescent age group (odds ratio [OR] = 8.83, 95% confidence interval [CI] = 1.47-53.11), uncircumcised males (OR = 4.52, 95% CI = 1.27-16.08), Hispanic ethnicity (OR = 4.37, 95% CI = 1.14-16.82), and hospitalization within the preceding 3 months (OR = 4.73, 95% CI = 1.38-16.23) were associated with FGC nonsusceptibility among TGC susceptible Enterobacteriaceae pathogens. De-escalation occurred in 55.8% of diagnosed UTIs eligible for de-escalation at discharge. Urine white blood cell (WBC) count >5 (OR = 2.89, 95% CI = 1.14-7.21), serum WBC count (OR = 1.04, 95% CI = 1.01-1.07), and having only one narrow-spectrum treatment option (OR = 5.1, 95% CI = 2.43-10.66) were associated with unnecessarily broad-spectrum definitive treatment. Conclusion and Relevance: FGC would be an appropriate narrow-spectrum empiric agent for UTIs at our institution. The factors associated with FGC nonsusceptibility can further stratify empiric treatment decisions. The factors associated with unnecessarily broad-spectrum definitive treatment illustrate areas for educational efforts and future research regarding UTI treatment.

Clinical Characteristics, Medication Prescription Pattern, and Treatment Outcomes at the Neonatal Intensive Care Unit of a Tertiary Health-Care Facility in Ghana

OBJECTIVE

Neonates are more susceptible to infections, as well as medication toxicities. This study, therefore, sought to describe the clinical characteristics, medication prescription pattern, and treatment outcomes for neonates admitted to the neonatal intensive care unit (NICU) of a tertiary health-care facility in Ghana.

METHODS

A retrospective cross-sectional study was conducted to ascertain clinical records, conditions for admission, spectrum of medications prescribed, and treatment outcomes from neonatal patient folders.

FINDINGS

Of 667 folders reviewed (51.4% males and 48.6% female), 61.8% were preterm (mean gestational age: 34.2 ± 3.6 weeks), 64.6% had low birth weight (LBW) (mean birth weight: 2.1 ± 0.9 kg), 90.6% were delivered through spontaneous vaginal delivery, and 57.4% delivered at the tertiary health-care facility. Of the 667 neonates, 70%, 27.1%, and 2.9% were queried with one, two, or three medical conditions, respectively. Respiratory distress, preterm, and pyrexia were common single queried conditions (88.5%). LBW, hypothermia, and single queried medical conditions were associated (P ≤ 0.0001) with preterm male neonates. The mean duration of stay of preterm neonates was 3.5 ± 3.2 days (term babies: 1-2 days [P = 0.0085]). Of 1,565 medications prescribed to the 667 neonates, 67.5% were antibacterial, with gentamicin (53.0%) being the most prescribed. 98.4% of neonates were prescribed at least one medication (i.e., 67.5% were prescribed antibacterial medications, 14.6% supplements, 11.0% bronchodilators, and 7.0% antiseizure); mean medication combination 2.6 ± 0.8 per neonate. Majority (75.4%) of the cases reviewed had treatment success.

CONCLUSION

Respiratory distress and preterm deliveries are predominant presenting conditions, with antibacterial medication, mainly gentamicin and ampicillin, on prescription. Treatment success is significantly high at the NICU.

Community-acquired serious bacterial infections in the first 90 days of life: a revisit in the era of multi-drug-resistant organisms

BACKGROUND

Infants in the first 90 days of life are more prone to develop serious bacterial infections (SBIs). Multi-drug-resistant organisms (MDROs) are emerging as important pathogens causing SBIs. We reviewed the epidemiology of SBIs in infants 0-90 days old and compared the clinical features, laboratory values and final outcome for SBIs due to MDROs vs. non-MDROs.

METHODS

Episodes of culture-proven SBIs (bacteremia, urinary tract infections, or meningitis) with age at onset of 0-90 days during a 7-year period were retrospectively reviewed. Health care-associated infections were excluded. We collected demographics, clinical features, and laboratory and microbiology data. We compared clinical characteristics, laboratory data, microbiologic results and final outcome for SBIs due to MDROs vs. non-MDROs.

RESULTS

Ninety-four episodes (88 patients) including bacteremia (42.6%), urinary tract infections (54.3%) and meningitis (3.1%) were caused by Gram-negative bacteria (67%), and Gram-positive bacteria (33%). Escherichia coli, Klebsiella pneumoniae and GBS were the most common causes. MDROs caused SBIs in 39 patients (44.3%). SBIs due to MDROs were associated with more delay in providing targeted antimicrobial therapy compared to non-MDROs (74.4% vs. 0%, P ≤ 0.001), but no difference in case-fatality rate (12.8% vs. 12.2%, P = 1.0). Clinical features or basic laboratory values were not statistically different between the two groups.

CONCLUSIONS

The bacteriology of SBIs in the first 90 days of life is changing to include more MDROs, which causes more delay in providing targeted antimicrobial therapy. Awareness of the local epidemiology is crucial to ensure appropriate antibiotics are provided in a timely manner.

Length of Stay and Complications Associated With Febrile Infants <90 Days of Age Hospitalized in the United States, 2000-2012

OBJECTIVES

It is not known how changes in the epidemiology of serious bacterial infection (SBI) and greater availability of rapid viral diagnostic tests have impacted the hospital length of stay (LOS) and associated complications among young infants with suspected SBI.

METHODS

We used national administrative data from the Healthcare Cost and Utilization Project Kids' Inpatient Database and other state-specific data to identify febrile infants <90 days of age hospitalized in 2000, 2003, 2006, 2009, and 2012. We used multivariate analysis to determine LOS, risk factors for prolonged LOS, and complications of care among infants with isolated fever or viral respiratory disease, without concomitant serious infection.

RESULTS

We identified 44 875 infants. LOS for each clinical group did not change over time in a clinically significant way. Mean LOS was ≤2 days for approximately two-thirds of all infants and ≥4 days for 11% in each clinical group. Factors associated with longer LOS included age <31 days, critical clinical status, concomitant chronic disease, and the presence of complications (P < .05). We identified 289 (0.8%) infants with 351 complications of care, 18 (6%) of whom had >1. These infants had longer LOS (P < .001), and those with chronic disease and older age were at increased risk (P < .01).

CONCLUSIONS

Despite the changing epidemiology of SBI and increased availability of viral diagnostic testing, we did not detect a clinically significant change in LOS for febrile infants with suspected SBI. Complications associated with hospitalization of these infants was associated with increased LOS.

Efficacy of Empiric Treatment of Urinary Tract Infections in Neonates and Young Infants

Background. The antibiotic resistance patterns of young infants with urinary tract infections (UTIs) have evolved over the past 2 decades. Whether current empiric antibiotic regimens are sufficient in this age group is unknown. Methods. A retrospective review of patients aged 0 to 60 days admitted with a UTI discharge diagnosis. Results. Overall susceptibility to empiric antibiotics was 87%. Antibiotic resistance and length of stay were highest among those who were afebrile, those admitted to the intensive care unit, and those with culture diagnosis of enterococcal infection. The sensitivity and specificity of ultrasound as a screening tool for genitourinary anomaly was 70% and 40%, respectively, with a positive predictive value of 31.8%. Conclusions. Empiric antibiotic regimens cover a high percentage of UTIs in infants. However, high rates of resistance and prolonged length of stay in patients with enterococcal infection highlight the need for continued surveillance of such patients in this age group.

Epidemiology and Etiology of Invasive Bacterial Infection in Infants ≤60 Days Old Treated in Emergency Departments

OBJECTIVES

To help guide empiric treatment of infants ≤60 days old with suspected invasive bacterial infection by describing pathogens and their antimicrobial susceptibilities.

STUDY DESIGN

Cross-sectional study of infants ≤60 days old with invasive bacterial infection (bacteremia and/or bacterial meningitis) evaluated in the emergency departments of 11 children's hospitals between July 1, 2011 and June 30, 2016. Each site's microbiology laboratory database or electronic medical record system was queried to identify infants from whom a bacterial pathogen was isolated from either blood or cerebrospinal fluid. Medical records of these infants were reviewed to confirm the presence of a pathogen and to obtain demographic, clinical, and laboratory data.

RESULTS

Of the 442 infants with invasive bacterial infection, 353 (79.9%) had bacteremia without meningitis, 64 (14.5%) had bacterial meningitis with bacteremia, and 25 (5.7%) had bacterial meningitis without bacteremia. The peak number of cases of invasive bacterial infection occurred in the second week of life; 364 (82.4%) infants were febrile. Group B streptococcus was the most common pathogen identified (36.7%), followed by Escherichia coli (30.8%), Staphylococcus aureus (9.7%), and Enterococcus spp (6.6%). Overall, 96.8% of pathogens were susceptible to ampicillin plus a third-generation cephalosporin, 96.0% to ampicillin plus gentamicin, and 89.2% to third-generation cephalosporins alone.

CONCLUSIONS

For most infants ≤60 days old evaluated in a pediatric emergency department for suspected invasive bacterial infection, the combination of ampicillin plus either gentamicin or a third-generation cephalosporin is an appropriate empiric antimicrobial treatment regimen. Of the pathogens isolated from infants with invasive bacterial infection, 11% were resistant to third-generation cephalosporins alone.