The changing spectrum of neonatal infectious disease

Neonatal Nasopharyngeal Bacterial Colonization: Prevalence, Antimicrobial Resistance, and Concomitant Early-onset Sepsis

Background: Early-onset neonatal sepsis (ENOS) is one of the most common causes of mortality in neonates. The bacteria causing ENOS are generally transferred from the mother to the infant before or during labor. Objectives: This study aimed to determine the prevalence rate of nasopharyngeal colonization with common bacterial agents causing ENOS and their relationship with blood culture outcomes in neonates. Methods: All neonates transferred to the neonatal intensive care unit were included in the study. Posterior pharynx secretions were swabbed and cultured in blood agar and MacConkey agar. Also, a blood specimen from each neonate was inoculated into a blood culture bottle. The grown bacteria were identified by biochemical standard tests. The antibiotic sensitivity test was performed by the disk diffusion method using Mueller-Hinton agar, and the results were evaluated according to the CLSI guidelines. Results: The pharyngeal specimens collected from 114 newborns were positive in 83 (72.8%) cases. Staphylococcus epidermidis was the most common bacterium in all weight groups. However, the isolates of Klebsiella, Escherichia coli, S. aureus, and Streptococcus agalactiae were also high. Thirteen newborns died. Neonates’ pharyngeal specimens were positive among 11 (84.6%) cases who died and 101 (71.2%) neonates who survived. Twelve neonates had positive blood cultures. Simultaneous positive blood and pharyngeal cultures were reported in eight (7%) cases, in which the bacterial isolates from blood and pharyngeal samples were similar in three cases (37.5%). Among pharyngeal isolates, E. coli was resistant to ampicillin in 100% and gentamicin, cefotaxime, and ceftazidime in 50% of the cases. Also, S. epidermidis and Acinetobacter isolates from blood samples were resistant to ampicillin in 100% of the cases. Conclusions: Staphylococcus epidermidis accounted for 38.6% of bacteria cultured from pharyngeal swabs and 66.7% of bacteria cultured from blood samples, 37.5% of which were resistant to ampicillin and 100% were sensitive to vancomycin. One-hundred percent of E. coli cultures from neonatal pharynges were resistant to ampicillin and about 50% of them were resistant to gentamicin, cefotaxime, and ceftriaxone.

Microbial Contamination in Hospital Environment Has the Potential to Colonize Preterm Newborns' Nasal Cavities

Infants born before 28 weeks are at risk of contracting healthcare-associated infections (HAIs), which could be caused by pathogens residing on contaminated hospital surfaces. In this longitudinal study, we characterized by NGS the bacterial composition of nasal swabs of preterm newborns, at the time of birth and after admission to the Neonatal Intensive Care Unit (NICU), comparing it with that of the environmental wards at the time of delivery and during the hospitalization. We characterized the resistome on the samples too. The results showed that environmental microorganisms responsible for HAIs, in particular Staphylococcus spp., Streptococcus spp., Escherichia-Shigella spp., and K. pneumoniae, were detected in higher percentages in the noses of the babies after 13 days of hospitalization, in terms of the number of colonized patients, microorganism amount, and relative abundance. The analysis of nasal bacteria resistome evidenced the absence of resistance genes at the time of birth, some of which appeared and increased after the admission in the NICU. These data suggest that hospital surface microbiota might be transported to respiratory mucosae or other profound tissues. Our study highlights the importance of a screening that allows characterizing the microbial profile of the environment to assess the risk of colonization of the newborn.

Vaccination in preterm and low birth weight infants in India

In India, the high neonatal and infant mortality rate is due in part to an increasing number of preterm and low birth weight (LBW) infants. Given the immaturity of immune system, these infants are at an increased risk of hospitalization and mortality from vaccine-preventable diseases (VPDs). In this narrative review, we screened the scientific literature for data on the risk of VPDs, vaccination delay and factors related to it in Indian preterm and LBW infants. Although routine childhood vaccinations are recommended regardless of gestational age or birth weight, vaccination is often delayed. It exposes these infants to a higher risk of infections, their associated complications, and death. After-birth complications, lack of awareness of recommendations, vaccine efficacy and effectiveness and concerns related to safety are some of the common barriers to vaccination. Awareness campaigns might help substantiate the need for (and value of) vaccination in preterm and LBW infants.

What is the context?

In India, the high neonatal mortality rate is due in part to an increasing number of pretern and low birth weight intants.

Affected infants have a poorly developed inmune system and are more susceptible to contracting vaccine-preventable diseases.

The Indian Academy of Pediatrics recommends vaccination according to the same schedule used for full term infants, following chronological (not gestational) age.

Delays in vaccinations increase the risk of preventable infections.

What is new?

Our review of the scientific literature shows that, in India:

infections have more serious conseuences in preterm and low birth weight infants

delays to vaccinate affected infants are common, mostly due to safety and effectiveness concerns from parents and healthcare pracitionrs.

What is the impact?

Improving mternal nutritional status and immunization, and perinatal care could help reduce the number of preterm and low birth weight infants.

Combining maternal immunization with vaccination of affected infants can confer safe and effective protection.

Awareness campaigns for parents and healthcare practitioners could address the issue of vaccination delay in pretern and low birth weight infants in India.

Association between Tumor Necrosis Factor-α Promoter -308 G/A Polymorphism and Early Onset Sepsis in Preterm Infants

Early-onset neonatal sepsis (EOS) is diagnosed during the first 7 days of neonatal life and is the major cause of morbidity and mortality among preterm infants. Genetic predisposition may have an impact on EOS susceptibility and outcome. The aim of our study was to explore the association between TNF-α -308 G/A or IL-6 -174 G/C gene polymorphism and the susceptibility and outcome of EOS in preterm infants. The study included 471 preterm infants: 282 with EOS (151 with culture proven sepsis and 131 with clinical sepsis) and 189 without infection (control group). TNF-α -308 G/A and IL-6 -174 G/C were genotyped using Real-time RCR method. We observed significantly higher frequency of A allele of TNF-α -308 G/A polymorphism in blood culture proven EOS (p = 0.017) or clinical EOS (p = 0.025) compared with the control group. Logistic regression confirmed significant association between TNF-α -308 GA+AA genotypes and development of culture proven EOS (B = -0.718, p = 0.013) or clinical EOS (B = -0.602, p = 0.027). No significant differences in IL6 -174G/C alleles or genotypes distribution have been observed between culture proven EOS group, clinical EOS group and the control group. An association between TNF-α -308 G/A or IL-6 -174 G/C genotypes and EOS lethal outcome was not observed (p = 0.652 and p = 0.384, respectively). According to our analysis of large cohort of preterm infants with clearly defined EOS groups, the TNF-α -308 A allele may be a risk factor for the EOS occurrence.

Development, evaluation and validation of a screening tool for late onset bacteremia in neonates - a pilot study

Background

Clinical and laboratory parameters can aid in the early identification of neonates at risk for bacteremia before clinical deterioration occurs. However, current prediction models have poor diagnostic capabilities. The objective of this study was to develop, evaluate and validate a screening tool for late onset (> 72 h post admission) neonatal bacteremia using common laboratory and clinical parameters; and determine its predictive value in the identification of bacteremia.

Methods

A retrospective chart review of neonates admitted to a neonatal intensive care unit (NICU) between March 1, 2012 and January 14, 2015 and a prospective evaluation of all neonates admitted between January 15, 2015 and March 30, 2015 were completed. Neonates with late-onset bacteremia (> 72 h after NICU admission) were eligible for inclusion in the bacteremic cohort. Bacteremic patients were matched to non-infected controls on several demographic parameters. A Pearson’s Correlation matrix was completed to identify independent variables significantly associated with infection (p < 0.05, univariate analysis). Significant parameters were analyzed using iterative binary logistic regression to identify the simplest significant model (p < 0.05). The predictive value of the model was assessed and the optimal probability cut-off for bacteremia was determined using a Receiver Operating Characteristic curve.

Results

Maximum blood glucose, heart rate, neutrophils and bands were identified as the best predictors of bacteremia in a significant binary logistic regression model. The model’s sensitivity, specificity and accuracy were 90, 80 and 85%, respectively, with a false positive rate of 20% and a false negative rate of 9.7%. At the study bacteremia prevalence rate of 51%, the positive predictive value, negative predictive value and negative post-test probability were 82, 89 and 11%, respectively.

Conclusion

The model developed in the current study is superior to currently published neonatal bacteremia screening tools. Validation of the tool in a historic data set of neonates from our institution will be completed.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1633-1) contains supplementary material, which is available to authorized users.

Multiple antibiotic resistance as a risk factor for mortality and prolonged hospital stay: A cohort study among neonatal intensive care patients with hospital-acquired infections caused by gram-negative bacteria in Vietnam

BACKGROUND

Antibiotic resistance (ABR) is an increasing burden for global health. The prevalence of ABR in Southeast Asia is among the highest worldwide, especially in relation to hospital-acquired infections (HAI) in intensive care units (ICU). However, little is known about morbidity and mortality attributable to ABR in neonates.

AIM

This study aimed to assess mortality and the length of hospitalization attributable to ABR in gram-negative bacteria (GNB) causing HAI in a Vietnamese neonatal ICU (NICU).

METHODS

We conducted a prospective cohort study (n = 296) in a NICU in Hanoi, Vietnam, from March 2016 to October 2017. Patients isolated with HAI caused by GNB were included. The exposure was resistance to multiple antibiotic classes, the two outcomes were mortality and length of hospital stay (LOS). Data were analysed using two regression models, controlling for confounders and effect modifiers such as co-morbidities, time at risk, severity of illness, sex, age, and birthweight.

RESULTS

The overall case fatality rate was 44.3% and the 30 days mortality rate after infection was 31.8%. For every additional resistance to an antibiotic class, the odds of a fatal outcome increased by 27% and LOS increased by 2.1 days. These results were statistically significant (p < 0.05).

CONCLUSION

ABR was identified as a significant risk factor for adverse outcomes in neonates with HAI. These findings are generally in line with previous research in children and adults. However, heterogeneous study designs, the neglect of important confounders and varying definitions of ABR impair the validity, reliability, and comparability of results.

The role of coagulase-negative staphylococci in early onset sepsis in a large European cohort of very low birth weight infants

BACKGROUND

Early Onset Sepsis (EOS) is associated with increased major morbidity and mortality rates among very low birth weight (VLBW) infants. The epidemiology is changing in response to evolving medical practice. The objective of the study was to evaluate EOS epidemiology, risk factors, mortality and major morbidity rates among VLBW infants within a European cohort.

METHODS

Data from VLBW infants born from 2006 through 2009 was collected by neonatal units participating in the EuroNeoNet initiative. Univariate and multivariate analyses were performed to assess the independent association of EOS with VLBW infant's perinatal characteristics, morbidity and mortality rates.

RESULTS

The cohort included 14,719 infants, 391 developed EOS (2.7%). The most common pathogen responsible for EOS was Gram-positive bacteria (53.9%). Coagulase-negative staphylococci (CoNS) were isolated in 22.5% of episodes. Antenatal steroids exposure, single gestation, very low gestational age and birth weight, low 5 minute Apgar score and delivery room resuscitation were independently associated with EOS. EOS was also associated with a longer hospital stay, increased risk of mortality [adjusted odd ratio (aOR): 2.4; 95% Confidence Interval (CI): 1.9-3.1], respiratory distress syndrome (OR: 1.4; 95% CI: 1.1-1.9), severe intraventricular haemorrhage (aOR: 2.1; 95%CI: 1.6-2.8) and severe retinopathy of prematurity (aOR: 5; 95% CI: 1.9-13.3). Morbidity and mortality rates of infants with EOS caused by CoNS were similar to those of infants with EOS caused by other pathogens.

CONCLUSIONS

VLBW infants with EOS are at an increased risk of mortality and major morbidities. CoNS was a significant cause of sepsis, infants with CoNS were at a similarly high risk of complication of prematurity and mortality as those with EOS caused by other organisms.

The impact of staffing on central venous catheter-associated bloodstream infections in preterm neonates - results of nation-wide cohort study in Germany

Background

Very low birthweight (VLBW) newborns on neonatal intensive care units (NICU) are at increased risk for developing central venous catheter-associated bloodstream infections (CVC BSI). In addition to the established intrinsic risk factors of VLBW newborns, it is still not clear which process and structure parameters within NICUs influence the prevalence of CVC BSI.

Methods

The study population consisted of VLBW newborns from NICUs that participated in the German nosocomial infection surveillance system for preterm infants (NEO-KISS) from January 2008 to June 2009. Structure and process parameters of NICUs were obtained by a questionnaire-based enquiry. Patient based date and the occurrence of BSI derived from the NEO-KISS database. The association between the requested parameters and the occurrance of CVC BSI and laboratory-confirmed BSI was analyzed by generalized estimating equations.

Results

We analyzed data on 5,586 VLBW infants from 108 NICUs and found 954 BSI cases in 847 infants. Of all BSI cases, 414 (43%) were CVC-associated. The pooled incidence density of CVC BSI was 8.3 per 1,000 CVC days. The pooled CVC utilization ratio was 24.3 CVC-days per 100 patient days. A low realized staffing rate lead to an increased risk of CVC BSI (OR 1.47; p=0.008) and also of laboratory-confirmed CVC BSI (OR 1.78; p=0.028).

Conclusions

Our findings show that low levels of realized staffing are associated with increased rates of CVC BSI on NICUs. Further studies are necessary to determine a threshold that should not be undercut.