The changing profile of infant mortality from bacterial, viral and fungal infection over two decades

In Utero Exposure to Antibiotics and Risk of Serious Infections in the First Year of Life

INTRODUCTION AND OBJECTIVE

Given the high prevalence of antibiotic prescription during pregnancy in France and previous studies suggesting an increased risk of infection in offspring with such exposures, our study aimed to investigate the association between prenatal exposure to systemic antibiotics and serious infections in full-term infants during their first year of life.

METHODS

We conducted a retrospective population-based cohort study on singleton, full-term liveborn non-immunocompromised infants, using the French National Health Data System (SNDS) between 2012 and 2021. Systemic antibiotic dispensing in ambulatory care settings during pregnancy defined the exposure. Outcomes concerned serious infections (i.e., infections requiring hospitalization) in offspring identified between 3 and 12 months of life, hence excluding infections of maternal origin. Adjusted odds ratios (aORs) were estimated using logistic regression with multivariate models to control for potential confounders.

RESULTS

Of 2,836,630 infants included, 39.6% were prenatally exposed to systemic antibiotics. Infants prenatally exposed to antibiotics had a higher incidence of serious infections compared with unexposed infants {aOR 1.12 [95% confidence interval (95% CI) 1.11-1.13]}. Similar associations were observed according to the timing of exposure during pregnancy, antibiotic class, and site of infections. The strongest association was observed when infants were prenatally exposed to three or more antibiotic courses during pregnancy [aOR 1.21 (95% CI 1.19-1.24)]. Limitations include residual confounders, such as genetic susceptibility to infections and the role of the underlying pathogen agent.

CONCLUSION

Prenatal exposure to systemic antibiotics is very common and is associated with a weak yet significant associations with subsequent serious infectious events during the first year of life. While our study revealed associations, it is important to note that causation cannot be established, given the acknowledged limitations, including potential confounding by indication.

Association of Positive Bacterial Cultures Obtained from the Throat, Anus, Ear, Bronchi and Blood in Very-Low-Birth-Weight Premature Infants with Severe Retinopathy of Prematurity-Own Observations

BACKGROUND

The causative factors responsible for the development of Retinopathy of Prematurity (ROP) are still unexplored. Therefore, one of the most important factors can be perinatal inflammation.

METHODS

This retrospective study included 114 premature infants (228 eyes) meeting a birth criteria of ≤ 32 weeks gestational age (GA) and a birth weight (BW) ≤ 1710. Examined Group (EG) n = 51 of BW 852.7 ± 255.7; GA 26.3 ± 2.0 with severe ROP treated by diode laser or anti-VEGF intravitreal injection. Control Group (CG) n = 63 of BW 1313.9 ± 284.5; GA 28.8 ± 1.6 without ROP. Microbiological bacterial and fungal cultures of the ear, anus, bronchial throat and blood were taken. Medical data and laboratory tests in correlation to 3 ROP and A-ROP were analysed.

RESULTS

Positive bacterial tests dominated in EG, 47% vs. CG, 23%. Significant correlations between positive cultures obtained from natural cavities: anus (p < 0.001), throat (p = 0.002), as well as from blood (p = 0.001) and severe ROP which requires diode laser and anti-VEGF treatment were noted. Significant inflammation markers which correlate with the development of severe ROP are Klebsiella pneumoniae (KP) (p = 0.002) and Coagulase-negative Staphylococci (CoNS) (p < 0.001). CoNS, p < 0.001; KP, p = 0.002; the remaining Maltophilia stenotrophomonas (MS); Staphylococcus aureus (SA), p = 0.005; and Enterobacter cloacae (EC), p = 0.02 were the most frequent bacteria in severe ROP. High levels of white blood cells (WBC), C-reactive protein (CRP), lymphocytes (LYM) and low thrombocytes (PLT) correlated sequentially with (Odds Ratio, OR) CoNS (2.3); MS (5.9); KP (3.1); and all positive cultures (APC) (9.5). An important correlation between the BPD-EC (4.3); intrauterine inflammation-KP (3.4); PDA-EC (3.9); and asphyxia-CoNS (3.0) was identified.

CONCLUSIONS

It cannot be ruled out that positive microbiological results of blood, anal and pharyngeal cultures may become prognostic markers for the early development of ROP, which would enable early initiation of ophthalmological treatment in premature infants from the VLBW group.

GWAS on birth year infant mortality rates provides evidence of recent natural selection

Following more than a century of phenotypic measurement of natural selection processes, much recent work explores relationships between molecular genetic measurements and realized fitness in the next generation. We take an innovative approach to the study of contemporary selective pressure by examining which genetic variants are “sustained” in populations as mortality exposure increases. Specifically, we deploy a so-called “regional GWAS” (genome-wide association study) that links the infant mortality rate (IMR) by place and year in the United Kingdom with common genetic variants among birth cohorts in the UK Biobank. These cohorts (born between 1936 and 1970) saw a decline in IMR from above 65 to under 20 deaths per 1,000 live births, with substantial subnational variations and spikes alongside wartime exposures. Our results show several genome-wide significant loci, including LCT and TLR10/1/6, related to area-level cohort IMR exposure during gestation and infancy. Genetic correlations are found across multiple domains, including fertility, cognition, health behaviors, and health outcomes, suggesting an important role for cohort selection in modern populations.

From causes of aging to death from COVID-19

COVID-19 is not deadly early in life, but mortality increases exponentially with age, which is the strongest predictor of mortality. Mortality is higher in men than in women, because men age faster, and it is especially high in patients with age-related diseases, such as diabetes and hypertension, because these diseases are manifestations of aging and a measure of biological age. At its deepest level, aging (a program-like continuation of developmental growth) is driven by inappropriately high cellular functioning. The hyperfunction theory of quasi-programmed aging explains why COVID-19 vulnerability (lethality) is an age-dependent syndrome, linking it to other age-related diseases. It also explains inflammaging and immunosenescence, hyperinflammation, hyperthrombosis, and cytokine storms, all of which are associated with COVID-19 vulnerability. Anti-aging interventions, such as rapamycin, may slow aging and age-related diseases, potentially decreasing COVID-19 vulnerability.

Criteria for assigning cause of death for stillbirths and neonatal deaths in research studies in low-middle income countries

Accurate knowledge regarding cause of death (COD) for stillbirths and neonatal deaths is crucial, especially in low-income countries, in order for public health and medical officials to choose appropriate interventions likely to reduce these deaths. To date, many of the COD studies in these areas have relied only on obstetric or neonatal clinical information and the determination of COD is likely to be inaccurate. Information related to infectious COD is especially lacking. Thus, without more sophisticated testing, data as currently collected only provide a very weak approximation of the COD and may well lead to adoption of interventions of limited usefulness. In this commentary, we propose recommendations regarding the type of data needed to determine with reasonable accuracy the COD for stillbirths and neonatal deaths in low-resource settings. Using these data, and a method to determine the degree of certainty, we then propose definitions for the most common COD. Our goal is to reduce subjectivity and provide more specificity for the tests used in existing classification systems so that the methodology of COD determination is transparent and able to be replicated over time and from location to location.

Neonatal gram-negative infections, antibiotic susceptibility and clinical outcome: an observational study

BACKGROUND

Neonatal gram-negative (GN) infections are associated with high mortality and morbidity. Early appropriate antibiotic treatment is vital and gentamicin is the most frequently used antibiotic on neonatal units (NNUs). Antimicrobial breakpoints are predominantly based on adult data and the relationship between minimum inhibitory concentrations (MICs) and outcome in neonates is unclear. We aimed to determine the MIC of GN pathogens causing neonatal infections and relate this to clinical outcomes.

METHODS

MICs for eight antibiotics plus extended spectrum β-lactamase (ESBL) production were determined for invasive GN bacterial isolates from eight UK NNUs. European Committee on Antimicrobial Susceptibility Testing breakpoints were applied. MIC was correlated with clinical outcome using multivariable regression analysis.

RESULTS

118 isolates from 116 patients were analysed. The median birth gestation and postnatal age was 27 weeks (IQR 24.6-32.3) and 20 days (IQR 5-44), respectively. Pathogens included Escherichia coli (51%), Klebsiella spp (23%) and Enterobacter spp (22%). 10-day attributable mortality was 18.1% (21 patients) with the highest mortality from Pseudomonas aeruginosa infections. ESBL producers accounted for 13.8% of the isolates. In regression analysis, increasing gentamicin MIC was associated with increased mortality in gentamicin treated patients across the full MIC range (OR per log_e increase in MIC: 2.29; 95% CI 1.23 to 4.26, p=0.009), including susceptible isolates only (MIC ≤4) (OR 3.05; 95% CI 1.10 to 8.46, p=0.032).

CONCLUSIONS

Neonatal mortality from GN infections remains high and is associated with increasing gentamicin MIC, even for isolates deemed susceptible. A better understanding of population-specific MICs and aminoglycoside dosing is required to guide empiric antibiotic treatment.

Reportable Bacterial Infections among New York City-Born Infants, 2001-2009

OBJECTIVE

To determine rates of reportable bacterial infections among infants in New York City and identify populations at risk and preventable causes of morbidity.

STUDY DESIGN

This retrospective cohort study matched live births in New York City from 2001-2009 to reported cases of bacterial infections among infants less than 1 year of age. Characteristics recorded on birth certificates were compared between infants with bacterial enteric infection, bacterial nonenteric infection, and no reportable bacterial infection. Multinomial logistic regression and multivariable logistic regression were used to identify risk factors for infection.

RESULTS

Bacterial infection was reported in 4.6 cases per 1000 live births. Of 4524 infants with a reportable infection, the majority (2880, 63%) had an enteric infection. Asian/Pacific Islanders in Brooklyn were the borough-level race/ethnic group with the highest enteric infection rate (8.5 per 1000 live births). Citywide, infants with enteric infections were disproportionately male, from higher poverty neighborhoods, born to foreign-born mothers, and enrolled in Special Supplemental Food Program for Women, Infants, and Children or Medicaid. In contrast, infants with nonenteric infections were more likely to have low birthweight and mothers characterized by US birth and black race or white Hispanic race/ethnicity.

CONCLUSIONS

Distinct patterns of risk factors for enteric and nonenteric bacterial infections among infants were identified. The results suggest that infants born to Asian/Pacific Islander mothers residing in Brooklyn should be a focus of enteric disease prevention. More research is necessary to better understand what behaviors increase the risk of enteric disease in this population.

Prevalence of oral Candida in the first year of life

Colonisation of the gastrointestinal tract is influenced by primary microbial exposure and bioactive factors in breastmilk. The aim was to explore the prevalence of oral Candida in the first year of life in relation to selected exposures. Oral Candida was studied in 100 healthy infants at 4 and 8 weeks, 3, 6 and 12 months of age and related to delivery mode, birth weight, infant health and feeding, antibiotics, antimycotics, steroids and probiotics in mother and infant, living conditions, maternal smoking and infections The association between lactoferrin and antisecretory factor in breastmilk and maternal serum haemoglobin, transferrin, and ferritin levels in relation to oral Candida was also explored. About 11% to 15% of the infants had oral Candida at the respective age. Colonisation was fairly stable until 6 months of age. There was no conclusive impact of the investigated exposures at entry. Infants with a furry pet at home had a lower frequency of Candida at 3 months, (P < 0.05) whereas all but one colonised infant had older siblings at 12 months (P < 0.01). Lactoferrin in breastmilk was negatively associated with colonisation at 6 months of age. It is concluded that 11 to 15% had oral Candida. Exposure to furry pets and siblings impacted oral Candida.

Molecular analysis of fungal populations in patients with oral candidiasis using internal transcribed spacer region

Oral candidiasis is closely associated with changes in the oral fungal flora and is caused primarily by Candida albicans. Conventional methods of fungal culture are time-consuming and not always conclusive. However, molecular genetic analysis of internal transcribed spacer (ITS) regions of fungal rRNA is rapid, reproducible and simple to perform. In this study we examined the fungal flora in patients with oral candidiasis and investigated changes in the flora after antifungal treatment using length heterogeneity-polymerization chain reaction (LH-PCR) analysis of ITS regions. Fifty-two patients with pseudomembranous oral candidiasis (POC) and 30 healthy controls were included in the study. Fungal DNA from oral rinse was examined for fungal species diversity by LH-PCR. Fungal populations were quantified by real-time PCR and previously-unidentified signals were confirmed by nucleotide sequencing. Relationships between the oral fungal flora and treatment-resistant factors were also examined. POC patients showed significantly more fungal species and a greater density of fungi than control individuals. Sixteen fungi were newly identified. The fungal populations from both groups were composed predominantly of C. albicans, though the ratio of C. dubliniensis was significantly higher in POC patients than in controls. The diversity and density of fungi were significantly reduced after treatment. Furthermore, fungal diversity and the proportion of C. dubliniensis were positively correlated with treatment duration. These results suggest that C. dubliniensis and high fungal flora diversity might be involved in the pathogenesis of oral candidiasis. We therefore conclude that LH-PCR is a useful technique for diagnosing and assessing the severity of oral candidal infection.

Transport proteins promoting Escherichia coli pathogenesis

Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies.