Probiotics and prebiotics: role in prevention of nosocomial sepsis in preterm infants

Probiotics for the postoperative management of term neonates after gastrointestinal surgery

BACKGROUND

The intestinal microflora has an essential role in providing a barrier against colonisation of pathogens, facilitating important metabolic functions, stimulating the development of the immune system, and maintaining intestinal motility. Probiotics are live microorganisms that can be administered to supplement the gut flora. Neonates who have undergone gastrointestinal surgery are particularly susceptible to infectious complications in the postoperative period. This may be partly due to a disruption of the integrity of the gut and its intestinal microflora. There may be a role for probiotics in reducing the incidence of sepsis and improving intestinal motility, thus reducing morbidity and mortality and improving enteral feeding in neonates in the postoperative period.

OBJECTIVES

To evaluate the efficacy and safety of administering probiotics after gastrointestinal surgery for the postoperative management of neonates born from 35 weeks of gestation.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and trial registries in August 2023. We checked reference lists of included studies and relevant systematic reviews for additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that investigated the postoperative administration of oral probiotics versus placebo or no treatment in neonates born from 35 weeks of gestation who had one or more gastrointestinal surgical procedures. We applied no restrictions regarding the type or dosage of probiotics or the duration of treatment.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods, and we used GRADE to assess the certainty of evidence.

MAIN RESULTS

We identified one RCT that recruited 61 neonates with a gestational age of 35 weeks or more. All infants were admitted to a neonatal intensive care unit and had surgery for gastrointestinal pathologies. There may be little or no difference in proven sepsis (positive bacterial culture, local or systemic) between infants who receive probiotics compared with those who receive placebo (odds ratio (OR) 0.64, 95% confidence interval (CI) 0.16 to 2.55; 61 infants; low-certainty evidence). Probiotics compared to placebo may have little or no effect on time to full enteral feeds (mean difference (MD) 0.63 days, 95% CI -4.02 to 5.28; 61 infants; low-certainty evidence). There were no reported deaths prior to discharge from hospital in either study arm. Two weeks after supplementation, the infants who received probiotics had a substantially higher relative abundance of non-pathogenic intestinal microflora (Bifidobacteriaceae) than those who received placebo (MD 38.22, 95% CI 28.40 to 48.04; 39 infants; low-certainty evidence).

AUTHORS' CONCLUSIONS

This review provides low-certainty evidence from one small RCT that probiotics compared to placebo have little or no effect on the risk of proven sepsis (positive bacterial culture, local or systemic) or time to full-enteral feeds in neonates who have undergone gastrointestinal surgery. Probiotics may substantially increase the abundance of beneficial bacterial in the intestine of these neonates, but the clinical implications of this finding are unknown. There is a need for adequately powered RCTs to assess the role of probiotics in this population. We identified two ongoing studies. As neither reported the gestational age of prospective study participants, we are unsure if they will be eligible for inclusion in this review.

Targeting Risk Factors for the Control of Central Line-Associated Bloodstream Infection in the Neonatal Intensive Care Unit: A Single Tertiary Center Experience

Purpose: The aim of this study was to estimate the effect of targeting risk factors for the control of central line-associated bloodstream infection (CLABSI) among high-risk infants in a tertiary neonatal intensive care unit (NICU).Methods: Infants admitted to the NICU and diagnosed with CLABSI from January to December 2013 were eligible for inclusion to the study. The CLABSI group (n=47) was matched in a 1:2 ratio to the control group (n=94) based on gestational age, birth weight, and Score for Neonatal Acute Physiology-II. Risk factors for CLABSI were identified using the Cox proportional hazard model, and analysis of the effect of these risk factors targeting infection control was performed.Results: The risk factors associated with CLABSI were prolonged central line dwell days (adjusted hazard ratio [HR], 1.028; 95% confidence interval [CI], 1.011 to 1.045; P=0.001), use of a silicone catheter (adjusted HR, 5.895; 95% CI, 1.893 to 18.355; P=0.002), surgical treatment (adjusted HR, 3.793; 95% CI, 1.467 to 9.805; P=0.006), and less probiotic supplementation (adjusted HR, 0.254; 95% CI, 0.068 to 0.949; P=0.042). By targeting these risk factors with a quality improvement initiative, the mean CLABSI incidence rate per 1,000 catheter-days decreased from 6.6 to 3.1 (P=0.004).Conclusion: Targeting risk factors for infection control significantly reduced the rate of CLABSI among high-risk infants in the NICU.

Role of probiotics in prevention and treatment of enteric infections: a comprehensive review

Microorganisms that inhabits human digestive tract affect global health and enteric disorders. Previous studies have documented the effectiveness and mode of action of probiotics and classified as human-friendly biota and a competitor to enteric pathogens. Statistical studies reported more than 1.5 billion cases of gastrointestinal infections caused by enteric pathogens and their long-term exposure can lead to mental retardation, temporary or permanent physical weakness, and leaving the patient susceptible for opportunistic pathogens, which can cause fatality. We reviewed previous literature providing evidence about therapeutic approaches regarding probiotics to cure enteric infections efficiently by producing inhibitory substances, immune system modulation, improved barrier function. The therapeutic effects of probiotics have shown success against many foodborne pathogens and their therapeutic effectiveness has been exponentially increased using genetically engineered probiotics. The bioengineered probiotic strains are expected to provide a better and alternative approach than traditional antibiotic therapy against enteric pathogens, but the novelty of these strains also raise doubts about the possible untapped side effects, for which there is a need for further studies to eliminate the concerns relating to the use and safety of probiotics. Many such developments and optimization of the classical techniques will revolutionize the treatments for enteric infections.

Current and emerging treatments for neonatal sepsis

Introduction: Mortality due to sepsis is still prevalent, peaking at extreme ages of life including infancy. Despite many efforts, the peculiarity of the infant immune system has limited further advances in its treatment. Indeed, neonates experience a dramatic physiological transition from immune tolerance to the maternal antigens to functional maturity. Such a transition is extremely dynamic, as is the pathophysiology of infant sepsis, which is dependent on many infant, maternal, and environmental factors.Areas covered: In this review, the authors critically update and summarize the current paradigm of immunomodulation in infant sepsis. They confirm how exogenous stimulation of the immune system through intravenous immunoglobulin, colony stimulating factors, and granulocyte transfusion have failed to impact on the prognosis of infant sepsis. They also strongly support the beneficial effects of supplementation/replacement therapies with products naturally contained within maternal milk as well as antioxidant compounds.Expert opinion: Breastfeeding is beneficial against sepsis. Knowledge of the neonatal immune system is indeed too limited to effectively strengthen immune response by exogenous interventions, especially in preterm and low-birth-weight infants. Awareness of this limitation should pave the way for future studies (e.g. gender- and omics-based) aimed at better characterizing the infant immune system and promoting a more tailored approach.

Probiotics and Their Potential Preventive and Therapeutic Role for Cancer, High Serum Cholesterol, and Allergic and HIV Diseases

The potential health benefits of probiotics have long been elucidated since Metchnikoff and his coworkers postulated the association of probiotic consumption on human's health and longevity. Since then, many scientific findings and research have further established the correlation of probiotic and gut-associated diseases such as irritable bowel disease and chronic and antibiotic-associated diarrhea. However, the beneficial impact of probiotic is not limited to the gut-associated diseases alone, but also in different acute and chronic infectious diseases. This is due to the fact that probiotics are able to modify the intestinal microbial ecosystem, enhance the gut barrier function, provide competitive adherence to the mucosa and epithelium, produce antimicrobial substances, and modulate the immune activity by enhancing the innate and adaptive immune response. Nevertheless, the current literature with respect to the association of probiotic and cancer, high serum cholesterol, and allergic and HIV diseases are still scarce and controversial. Therefore, in the present work, we reviewed the potential preventive and therapeutic role of probiotics for cancer, high serum cholesterol, and allergic and HIV diseases as well as providing its possible mechanism of actions.

Immunomodulation to Prevent or Treat Neonatal Sepsis: Past, Present, and Future

Despite continued advances in neonatal medicine, sepsis remains a leading cause of death worldwide in neonatal intensive care units. The clinical presentation of sepsis in neonates varies markedly from that in older children and adults, and distinct acute inflammatory responses results in age-specific inflammatory and protective immune response to infection. This review first provides an overview of the neonatal immune system, then covers current mainstream, and experimental preventive and adjuvant therapies in neonatal sepsis. We also discuss how the distinct physiology of the perinatal period shapes early life immune responses and review strategies to reduce neonatal sepsis-related morbidity and mortality. A summary of studies that characterize immune ontogeny and neonatal sepsis is presented, followed by discussion of clinical trials assessing interventions such as breast milk, lactoferrin, probiotics, and pentoxifylline. Finally, we critically appraise future treatment options such as stem cell therapy, other antimicrobial protein and peptides, and targeting of pattern recognition receptors in an effort to prevent and/or treat sepsis in this highly vulnerable neonatal population.

Role of selenium supplementation in prevention of late onset sepsis among very low birth weight neonates: a systematic review of randomized controlled trials

Background: Neonatal sepsis is one of the most common causes of neonatal morbidity and mortality. Selenium has antioxidant and immune-modulating properties.Aim: The aim of this systematic review is to evaluate role of selenium supplementation in the prevention of late onset sepsis (LOS) among very low birth weight (VLBW) neonates.Methods: We searched literature for this review by searching the Cochrane Central Register of Controlled Trials (CENTRAL) electronic PubMed, Embase, and Google Scholar. We also searched for ongoing clinical trials.Results: This review included two randomized controlled trials (RCTs) that fulfilled inclusion criteria. There was statistically significant reduction in the incidence of LOS in the intervention group [23.7 versus 35.6%; relative risk (RR) 0.67; 95% CI 0.52-0.86; p= .001; number needed to treat (NNT) 8.4; 95% CI 5.2-20.96]. However, mortality due to any cause prior to hospital discharge was not statistically significant in between the groups (6.1% intervention group versus 6.9% control group; RR 0.88; 95% CI 0.49-1.61; p= .68).Conclusions: Evidences from current systematic review revealed that selenium supplementation has some role in the prevention of LOS. However, due to limited evidences and heterogeneity between studies, large RCTs are recommended among VLBW neonates.

Probiotics supplementation and length of hospital stay in neonates with gastrointestinal surgery

Any manipulation on open bowel causes interventional impact on gut microbiome, and surgical stress triggers bacterial translocation; thus, it will be fundamental to determine gut microbiome after surgery. Monitoring dynamic changes in microbiome of post-surgical infants who received probiotics and placebo could provide with important information about gut colonization and potential bacterial overgrowth. The purpose of this study is to assess the effect of probiotics supplementation on length of hospital stay, duration of parenteral nutrition, and feed tolerance in neonates after gastrointestinal surgery.

Mosapride combined with probiotics on gastrointestinal function and growth in premature infants

The aim of this study was to investigate the effects of mosapride combined with probiotics on gastrointestinal function and growth and development in premature infants. A total of 240 premature infants treated at Weifang People's Hospital between June 2012 and May 2015 who matched our criteria were randomly divided into three groups of 80 cases each. Group A received routine treatment, group B received routine treatment combined with live B. subtilis and E. faecium granules with multivitamins (Medilac-Vita), and group C received routine treatment and Saccharomyces boulardii sachets (Bioflor). Mosapride was administered to patients in groups B and C to promote intestinal peristalsis. Gastrin and bilirubin levels, as well as jaundice fade time, were recorded. Growth and development condition (i.e., head circumference and weight), duration and incidence of feeding intolerance (FI), as well as other symptoms were also analyzed. By day 14, gastrin concentrations in groups B and C were significantly higher than those in group A (P<0.05). Serum bilirubin levels in groups B and C showed a progressive decline from day 7 to day 14, and jaundice duration in group A was significantly longer (P<0.05). Furthermore, at 2 weeks, the average weight growth rate and head circumference were significantly greater in groups B and C, weight loss recovery time was shorter, and EUGR incidence was lower (P<0.05). The incidence rate of gastric retention and FI were lower in groups B and C than group A (P<0.05), and neonatal hyperbilirubinemia, parenteral nutrition-associated cholestasis, necrotizing enterocolitis, and neonatal sepsis incidence was significantly lower in groups B and C (P<0.05). Mosapride combined with probiotics can effectively reduce FI incidence in premature infants, shorten enteral feeding time, promote the absorption of required nutrients, and promote the development and recovery of early physiological weight loss in preterm infants.

Bacillus clausii for Prevention of Late-onset Sepsis in Preterm Infants: A Randomized Controlled Trial

BACKGROUND OF THE STUDY

Preterm infants are managed with antibiotics for sepsis, including suspected or probable sepsis. This leads to a delayed and abnormal colonization of the gut with potentially pathogenic organisms and a microbiome, which lacks biodiversity and increases the risk for late-onset sepsis (LOS). Probiotics have been proven to reduce the risk for necrotizing enterocolitis, but evidence for prevention of LOS is inconclusive. Probiotic effect depends also on the strain used, dose and indication for use. This study evaluated Bacillus clausii probiotic administered prophylactically to preterm neonates for prevention of LOS.

OBJECTIVES

To study B.clausii given prophylactically to preterm neonates for prevention of LOS.

DESIGN

Double-blinded, placebo-controlled, randomized trial.

SETTINGS

Tertiary care neonatal unit in India.

PARTICIPANTS

Consecutive preterm neonates <34 weeks, admitted from 1 March 2012 to 28 February 2014 were stratified as extreme preterm and very preterm.

INTERVENTION

Randomized to receive either probiotic or placebo for 6 weeks, discharge from hospital, death or occurrence of sepsis, whichever was earlier.

PRIMARY OUTCOME

Incidence of definite and probable LOS in probiotic group compared with placebo.

RESULTS

Of 326 eligible preterm infants, 244 were enrolled and 82 were excluded. Of these, 120 were stratified as extreme preterm and randomized to receive placebo (n = 59) and probiotic (n = 61). Of 124 babies stratified as very preterm, an equal number was randomized to receive placebo (n = 62) and probiotic (n = 62). There was no significant difference in the incidence of LOS between the two arms in the extreme preterm group [29% vs. 23%; relative risk (RR) 1.27; 95% confidence interval (CI) 0.88-1.66; p = 0.36] and the very preterm group (13% vs. 10%; RR 1.33; 95% CI 0.96-1.70; p = 0.32). Full feeds were achieved significantly faster in the probiotic group in both the extreme preterm (RR 0.82; 95% CI 0.74-0.88) and the very preterm (RR 0.67; 95% 0.32-0.77).

CONCLUSIONS

Prophylactic administration of B.clausii to preterm neonates did not result in a significant difference in the incidence of LOS as compared with placebo.

Late-Onset Bloodstream Infection and Perturbed Maturation of the Gastrointestinal Microbiota in Premature Infants

Background

Late-onset bloodstream infection (LO-BSI) is a common complication of prematurity, and lack of timely diagnosis and treatment can have life-threatening consequences. We sought to identify clinical characteristics and microbial signatures in the gastrointestinal microbiota preceding diagnosis of LO-BSI in premature infants.

Method

Daily faecal samples and clinical data were collected over two years from 369 premature neonates (<32 weeks gestation). We analysed samples from 22 neonates who developed LO-BSI and 44 matched control infants. Next-generation sequencing of 16S rRNA gene regions amplified by PCR from total faecal DNA was used to characterise the microbiota of faecal samples preceding diagnosis from infants with LO-BSI and controls. Culture of selected samples was undertaken, and bacterial isolates identified using MALDI-TOF. Antibiograms from bloodstream and faecal isolates were compared to explore strain similarity.

Results

From the week prior to diagnosis, infants with LO-BSI had higher proportions of faecal aerobes/facultative anaerobes compared to controls. Risk factors for LO-BSI were identified by multivariate analysis. Enterobacteriaceal sepsis was associated with antecedent multiple lines, low birth weight and a faecal microbiota with prominent Enterobacteriaceae. Staphylococcal sepsis was associated with Staphylococcus OTU faecal over-abundance, and the number of days prior to diagnosis of mechanical ventilation and of the presence of centrally-placed lines. In 12 cases, the antibiogram of the bloodstream isolate matched that of a component of the faecal microbiota in the sample collected closest to diagnosis.

Conclusions

The gastrointestinal tract is an important reservoir for LO-BSI organisms, pathogens translocating across the epithelial barrier. LO-BSI is associated with an aberrant microbiota, with abundant staphylococci and Enterobacteriaceae and a failure to mature towards predominance of obligate anaerobes.

Role of probiotics VSL#3 in prevention of suspected sepsis in low birthweight infants in India: a randomised controlled trial

OBJECTIVES

To assess the effect of the probiotic VSL#3 in prevention of neonatal sepsis in low birthweight (LBW) infants.

DESIGN

Randomised, double-blind, placebo-controlled trial.

SETTING

Community setting in rural India.

PARTICIPANTS

LBW infants aged 3-7 days.

INTERVENTIONS

Infants were randomised to receive probiotic (VSL#3, 10 billion colony-forming units (cfu)) or placebo for 30 days, and were followed up for 2 months.

MAIN OUTCOME MEASURE

Possible serious bacterial infection (PSBI) as per the Integrated Management of Neonatal Childhood Illnesses algorithm, as diagnosed by fieldworkers/physicians.

RESULTS

668 infants were randomised to VSL#3 and 672 to placebo. By intention-to-treat analysis, the risk of PSBI among infants in the overall population of LBW infants was not statistically significant (RR 0.79 (95% CI 0.56 to 1.03)). Probiotics reduced median days of hospitalisation (6 days vs 3 days in probiotics) (p=0.018) but not the risk of hospitalisation (RR 0.66 (95% CI 0.42 to 1.04). The onset of PSBI in 10% of infants occurred on the 40th day in the probiotics arm versus the 25th day in the control arm (p=0.063).

CONCLUSIONS

Daily supplementation of LBW infants with probiotics VSL#3 (10 billion cfu) for 30 days led to a non-significant 21% reduction in risk of neonatal sepsis. A larger study with sufficient power and a more specific primary end point is warranted to confirm the preventive effect of VSL#3 on neonatal sepsis in LBW infants.

TRIAL REGISTRATION NUMBER

The study is registered at the Clinical Trial Registry of India (CTRI/2008/091/000049).

Late-onset neonatal sepsis: recent developments

The incidence of neonatal late-onset sepsis (LOS) is inversely related to the degree of maturity and varies geographically from 0.61% to 14.2% among hospitalised newborns. Epidemiological data on very low birth weight infants shows that the predominant pathogens of neonatal LOS are coagulase-negative staphylococci, followed by Gram-negative bacilli and fungi. Due to the difficulties in a prompt diagnosis of LOS and LOS-associated high risk of mortality and long-term neurodevelopmental sequelae, empirical antibiotic treatment is initiated on suspicion of LOS. However, empirical therapy is often inappropriately used with unnecessary broad-spectrum antibiotics and a prolonged duration of treatment. The increasing number of multidrug-resistant Gram-negative micro-organisms in neonatal intensive care units (NICU) worldwide is a serious concern, which requires thorough and efficient surveillance strategies and appropriate treatment regimens. Immunological strategies for preventing neonatal LOS are not supported by current evidence, and approaches, such as a strict hygiene protocol and the minimisation of invasive procedures in NICUs represent the cornerstone to reduce the burden of neonatal LOS.

[Bacterial translocation: gap in the shield]

The gastrointestinal tract is not only regarded as a system where nutrient absorption takes place, but also as a vital barrier against intraluminal pathogens entering the circulation and the maintenance of immune homeostasis. Bacterial translocation is defined as the penetration of viable bacteria or bacterial compounds from the gastrointestinal tract to extraintestinal sites. This disorder has been described in several clinical conditions. The main promoting factors for bacterial translocation have been proposed to be changes in the intestinal microflora, mucosal barrier failure and defects in host immunity. The presence of bacterial translocation has been associated with higher complications and mortality rates; therefore it should be taken into account in the therapeutic strategies of patients with predisposing factors.

Bacterial colonization and intestinal mucosal barrier development

The intestinal tract is colonized soon after birth with a variety of ingested environmental and maternal microflora. This process is influenced by many factors including mode of delivery, diet, environment, and the use of antibiotics. Normal intestinal microflora provides protection against infection, ensures tolerance to foods, and contributes to nutrient digestion and energy harvest. In addition, enteral feeding and colonization with the normal commensal flora are necessary for the maintenance of intestinal barrier function and play a vital role in the regulation of intestinal barrier function. Intestinal commensal microorganisms also provide signals that foster normal immune system development and influence the ensuing immune responses. There is increasingly recognition that alterations of the microbial gut flora and associated changes in intestinal barrier function may be related to certain diseases of the gastrointestinal tract. This review summarizes recent advances in understanding the complex ecosystem of intestinal microbiota and its role in regulating intestinal barrier function and a few common pediatric diseases. Disruption in the establishment of a stable normal gut microflora may contribute to the pathogenesis of diseases including inflammatory bowel disease, nosocomial infection, and neonatal necrotizing enterocolitis.

High proportion of intestinal colonization with successful epidemic clones of ESBL-producing Enterobacteriaceae in a neonatal intensive care unit in Ecuador

Background and Aims

Neonatal infections caused by Extended-spectrum beta-lactamase (ESBL)-producing bacteria are associated with increased morbidity and mortality. No data are available on neonatal colonization with ESBL-producing bacteria in Ecuador. The aim of this study was to determine the proportion of intestinal colonization with ESBL-producing Enterobacteriaceae, their resistance pattern and risk factors of colonization in a neonatal intensive care unit in Ecuador.

Methods

During a three month period, stool specimens were collected every two weeks from hospitalized neonates. Species identification and susceptibility testing were performed with Vitek2, epidemiologic typing with automated repetitive PCR. Associations between groups were analyzed using the Pearson _X² test and Fisher exact test. A forward step logistic regression model identified significant predictors for colonization.

Results

Fifty-six percent of the neonates were colonized with ESBL-producing Enterobacteriaceae. Length of stay longer than 20 days and enteral feeding with a combination of breastfeeding and formula feeding were significantly associated with ESBL-colonization. The strains found were E. coli (EC, 89%) and K. pneumoniae (KP, 11%) and epidemiological typing divided these isolates in two major clusters. All EC and KP had bla_CTX-M group 1 except for a unique EC isolate that had bla_CTX-M group 9. Multi-locus sequence typing performed on the K. pneumoniae strains showed that the strains belonged to ST855 and ST897. The two detected STs belong to two different epidemic clonal complexes (CC), CC11 and CC14, which previously have been associated with dissemination of carbapenemases. None of the E. coli strains belonged to the epidemic ST 131 clone.

Conclusions

More than half of the neonates were colonized with ESBL-producing Enterobacteriaceae where the main risk factor for colonization was length of hospital stay. Two of the isolated clones were epidemic and known to disseminate carbapenemases. The results underline the necessity for improved surveillance and infection control in this context.

Microbial modulators for treatment of liver failure with endotoxemia: Research progress

Intestinal endotoxemia is one of the important mechanisms behind the onset and development of liver failure. Intestinal flora or intestinal barrier dysfunction can cause intestinal endotoxemia. Various kinds of microbial products can decrease serum levels of endotoxin and reduce complications and mortality by improving intestinal microflora imbalance and inhibiting Gram-negative bacterial overgrowth. Microbial modulators show significant therapeutic effects in the treatment of liver failure, which has become a research focus in improving endotoxemia associated with liver failure. However, the compatibility of various microbial modulators and antibiotics when combined should arouse the attention of clinicians. This article reviews the types of microbial modulators, their mechanisms of action and combination use with probiotics, and the compatibility when combined with antibiotics.