Child deaths caused by Klebsiella pneumoniae in sub-Saharan Africa and south Asia: a secondary analysis of Child Health and Mortality Prevention Surveillance (CHAMPS) data

Evaluation of capsule polysaccharide (CPS)-specific antibodies for broad recognition of prominent multidrug-resistant Klebsiella pneumoniae

Klebsiella pneumoniae is primarily an opportunistic pathogen known for causing healthcare-associated infections in individuals with significant risk factors and comorbidities. These bacteria are typically multidrug-resistant (MDR), a phenotype conferred in part by the production of extended-spectrum beta-lactamases and/or carbapenemases. By comparison, so-called hypervirulent K. pneumoniae (hvKp) are defined by their ability to cause severe community-acquired infections in otherwise healthy individuals. Although hvKp lineages have historically not been MDR, there has been a recent emergence of strains with both hypervirulence and multidrug resistance phenotypes. Treatment of infections caused by MDR K. pneumoniae can be difficult, and new preventative measures are needed. As a step toward the development of a vaccine directed to prevent or moderate infections caused by these pathogens, we tested the ability of capsule polysaccharide (CPS) derived from eight selected K. pneumoniae capsule types (KLs) to elicit rabbit antibodies that recognize important KLs isolated from human infections. Seventy-one out of 84 (84.5%) contemporary K. pneumoniae clinical isolates tested were recognized by CPS-specific rabbit antisera. There was the unexpected binding of the antibodies to some isolates with KLs not included in the CPS-antigen cocktails. Notably, rabbit IgG purified from CPS-specific antisera promoted and/or enhanced human PMN bactericidal activity toward all but one of the selected clinical isolates that were not killed by PMNs outright (in the absence of specific antibody). These data provide support to the idea that a CPS-antigen cocktail could be developed to protect against the K. pneumoniae KLs that are the most frequent cause of human infections.IMPORTANCEKlebsiella pneumoniae is among the leading causes of death by infectious agents. Many of the prominent K. pneumoniae lineages are resistant to multiple classes of antibiotics, and options for treatment are limited. New countermeasures that prevent infections are needed. Here we tested the ability of capsule polysaccharide (CPS) antigen mixtures (or cocktails) to elicit rabbit antibodies that recognize K. pneumoniae from a large collection of extended-spectrum beta-lactamase-producing clinical isolates. Importantly, these antibodies had the ability to promote opsonophagocytic killing by human PMNs. Our results provide proof-of-concept for a CPS vaccine cocktail approach that could be developed to prevent infections caused by the most important K. pneumoniae lineages.

Adherence to Perinatal Asphyxia or Sepsis Management Guidelines in Low- and Middle-Income Countries

Importance

Most of the 2.3 million annual neonatal deaths occur in sub-Saharan Africa and South Asia, with perinatal asphyxia and neonatal sepsis being the leading causes of neonatal mortality. Most neonatal deaths are considered preventable through high-quality clinical care, which includes adherence to clinical care guidelines.

Objective

To assess adherence to World Health Organization clinical care guidelines for management of perinatal asphyxia and neonatal sepsis and to identify patient-level factors in adherence among neonates who died from these conditions.

Design, Setting, and Participants

This cross-sectional study obtained data from December 2015 through October 2023 from the Child Health and Mortality Prevention Surveillance (CHAMPS) catchment areas in 7 low- and middle-income countries in sub-Saharan Africa (Ethiopia, Kenya, Mali, Mozambique, Sierra Leone, and South Africa) and South Asia (Bangladesh). Participants were neonates who were born alive and were aged 0 to 28 days at the time of death and had either perinatal asphyxia or neonatal sepsis.

Exposure

Medical records of neonates who died from perinatal asphyxia or neonatal sepsis determined by postmortem diagnostics.

Main Outcomes and Measures

The main outcome was the proportion of deceased neonates who received guideline-adherent treatments before they died. Mixed-effect multivariable logistic regression analyses were performed to identify factors associated with administration of at least bag-valve-mask (BVM) ventilation for perinatal asphyxia.

Results

Of the 1194 neonates (median [IQR] age at the time of death, 2 [1-6] days; 692 males [58.0%]) who died and were enrolled in CHAMPS with available clinical data, 476 (39.9%) died from perinatal asphyxia, 562 (47.0%) died from neonatal sepsis, and 156 (13.1%) from both conditions. These neonates had a median (IQR) birth weight of 2130 (1266-2988) g. For cases with perinatal asphyxia, guideline adherence ranged from 12.2% (n = 77) for adrenaline administration to 85.4% (540) for supplemental oxygen administration. Only 4.4% of neonates (28) with perinatal asphyxia received all recommended treatments. Among cases with neonatal sepsis, antibiotics were administered to 86.8% (623), although the recommended treatment was administered to only 61.0% (438). In multivariable analyses, neonates in whom clinicians accurately identified perinatal asphyxia were more likely to receive BVM ventilation than those who had received discordant antemortem and postmortem diagnoses (adjusted odds ratio, 2.00; 95% CI, 1.29-3.12).

Conclusions and Relevance

In this cross-sectional study, clinical care guideline adherence was suboptimal among neonates who died from perinatal asphyxia or neonatal sepsis. This finding underscores the critical need to increase adherence in regions with high rates of neonatal mortality and may inform strategies for strengthening health systems to support compliance with clinical care guidelines.

Epidemiology of Community-acquired Bacteremia Among Children One to Fifty-nine Months of Age Admitted to a Tertiary Hospital in Harar, Eastern Ethiopia

BACKGROUND

Community-acquired bacteremia is a leading cause of mortality in children <5 years of age in Ethiopia, yet data on etiology are scarce. We described the etiology and risk factors for bacteremia and in-hospital mortality in a tertiary hospital in eastern Ethiopia.

METHODS

Clinical surveillance was conducted at Hiwot Fana Comprehensive Specialized Hospital from December 2021 to November 2023. All admitted children 29 days to 59 months old were eligible for blood culture collection, excluding elective surgery or poisoning.

RESULTS

Of 3384 admissions, 2366 were sampled; 2070 had uncontaminated blood cultures, and 236 (11.4%) had bacteremia. The incidence risk was 69.7 per 1000 admissions. Klebsiella oxytoca (n = 59, 25.0%) and Klebsiella pneumoniae (n = 30, 12.7%) were the most common pathogens. The leading gram-positive pathogen was Streptococcus pneumoniae (n = 16, 6.8%). Gram-negative bacteria showed high resistance to ampicillin and gentamicin. Out of 2070, 122 died, yielding a case fatality ratio of 13.1% in bacteremia cases compared to 5.0% in nonbacteremic cases. Severe wasting [adjusted odds ratio, 1.49, (95% confidence interval: 1.10-2.01)] was associated with bacteremia risk. Bacteremic cases had a high risk of death across all nutritional statuses, while nonbacteremic admissions exhibited increased mortality risk with the severity of the nutritional status.

CONCLUSION

A high proportion of children admitted to Hiwot Fana Comprehensive Specialized Hospital had bacteremia with attendant high mortality. K. oxytoca was the commonest cause, showing significant resistance to first-line antimicrobials.

Clinical characteristics, antimicrobial resistance, and mortality of neonatal bloodstream infections in Northern Tanzania, 2022-2023

Neonatal bloodstream infections (BSI) make a substantial contribution to morbidity and mortality in low- and middle-income countries (LMICs), but data on the epidemiology and antimicrobial resistance (AMR) in Tanzania are limited. We describe the prevalence, resistance patterns, and associated factors of neonatal BSI at the Kilimanjaro Christian Medical Centre (KCMC), a large referral hospital in northern Tanzania. We conducted a prospective, observational study involving infants aged 0-60 days with perinatal risk factors or clinical signs of sepsis. Aerobic blood cultures were obtained at enrollment and monitored using a continuously monitored blood culture instrument. Antimicrobial susceptibility testing was performed using standard phenotypic methods. Vital status was obtained on days 2, 7, and 28 post-enrollment. BSI was defined as the isolation of established neonatal pathogens, including yeast and coagulase-negative Staphylococcus spp. (CoNS). Early-onset BSI occurred on day of life (DOL) 0-2, while late-onset BSI occurred on DOL 3 or later. Among 236 enrolled infants, blood culture was obtained in 233. BSI occurred in 106 (45.5%) of 233 infants, 50 (47.2%) were early-onset, and 56 (52.8%) were late-onset BSI. The isolated pathogens included 58 (54.7%) Gram-positive bacteria, 40 (37.7%) Gram-negative bacteria, and 8 (7.5%) yeast. CoNS (n = 55, 51.9%) and Klebsiella pneumoniae (n = 35, 33.0%) were the most common pathogens. Notably, all K. pneumoniae isolates were extended-spectrum beta-lactamase producers, resistant to ampicillin and ceftriaxone. Among the 56 infants who died, 29 (51.8%) had BSI; 11 (19.6%) infants with EO-BSI, and 18 (32.1%) with LO-BSI. Infants requiring respiratory support at admission had a 1.89-fold increased adjusted odds of BSI (95% CI, 1.05-3.44). We found high prevalence of neonatal BSI due to bacteria with a high prevalence of AMR, and BSI was associated with high mortality. There is an urgent need for effective preventive, diagnostic, and therapeutic interventions to address BSI among hospitalized infants in northern Tanzania.

Genomic relatedness of colonizing and invasive disease Klebsiella pneumoniae isolates in South African infants

Klebsiella pneumoniae (KPn) colonizes multiple anatomical sites and is a leading cause of invasive disease and death in African children; however, there is no comparative genomic analysis between colonizing and invasive strains. This study investigated the genomic relatedness of KPn colonizing and invasive isolates in South African infants; and evaluated the relative invasiveness of KPn isolates based on sequence types (ST), capsular (KL), and lipopolysaccharide (O) loci by calculating case-carrier ratios (CCRs). There was less genomic diversity amongst invasive (22 ST, 17 K-loci) than colonizing isolates (31 ST, 29 K-loci), with invasive isolates being 8.59-fold and 3.49-fold more likely to harbour genes encoding for multi-drug resistance and yersiniabactin production compared with colonizing isolates. The CCRs for KL102 and O1/O2v2 were > 1, and < 1 for KL8, ST1414, and O1O2v1. Identifying high-risk strains, including KL102 and O1O2v2, that may have a higher potential to cause invasive disease, could enhance risk assessment and management strategies in vulnerable populations.

Clinical, antibiotic resistance features, and treatment outcomes of Vietnamese patients with community-acquired sepsis caused by Klebsiella pneumoniae

Objectives

This study describes the clinical and paraclinical features, antibiotic resistance levels, and treatment outcomes of Klebsiella pneumoniae septicemia acquired in the Vietnamese community.

Methods

A cross-sectional descriptive study was conducted on 102 patients with community-acquired sepsis caused by K. pneumoniae from July 2018 to July 2023.

Results

K. pneumoniae-induced community sepsis had a septic shock rate of 13.7% and a death rate of 10.8%. Organ dysfunction rate in the patients with septic shock were higher than the patients without septic shock. The procalcitonin, creatinine, and platelet indexes increased more than in the septic shock group. K. pneumoniae strains were resistant to cephalosporins and quinolones (8-10%) and ampicillin (87%). Late hospitalization raises the risk of mortality by ∼3.5 times, and combination therapy with more than two kinds of antibiotics increases the risk of death by ∼1.8 times. The mortality rates were 9.1% and 63.6% after 4-6 and 2-3 weeks of therapy, respectively. Of the 11 patients who died, 90.9% died of septic shock, whereas 9.1% died of sepsis.

Conclusions

K. pneumoniae-induced community sepsis resulted in 13.7% septic shock, and 10.8% of the patients died. There was 87% K. pneumoniae resistance to ampicillin. Organ dysfunction and late hospitalization were associated with septic shock and death.

Characterization of carbapenem-resistant Klebsiella pneumoniae from blood cultures in Gaza Strip hospitals, Palestine

BACKGROUND

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a difficult to treat organism owing to limited therapeutic options. So far, little is known about the molecular characteristics of CRKP in Palestine.

OBJECTIVES

The aim of this study was to investigate the antimicrobial resistance patterns, multilocus sequence types (ST) and resistance genes among clinical K. pneumoniae isolates from hospitalized patients in Gaza Strip, Palestine.

METHODS

K. pneumoniae from blood cultures (n = 55) were collected at two hospitals in Gaza Strip (2023) and identified by MALDI-TOF-MS. Antimicrobial susceptibility testing was done using VITEK-2 automated systems. Carbapenemases were phenotypically detected. Whole genome sequencing (WGS) of all CRKP isolates was performed to assess determinants for carbapenem resistance and genotypes.

RESULTS

Of all K. pneumoniae isolates, 40 % (n = 22/55) were CRKP. Among CRKP, cefiderocol showed the least resistance (46 %, n = 10/22) while ceftazidime/avibactam showed a synergistic effect with aztreonam (36 %, n = 8/22). The majority (86 %, n = 19/22) of CRKP carried metallo-β-lactamases, and only 9 % (n = 2/22) encoded OXA-48 carbapenemase. WGS of CRKP revealed that the predominant genotype is multilocus sequence type ST147 harboring blaNDM-5 and blaCTX-M-15.

CONCLUSION

The proportion of CRKP among all K. pneumoniae from bloodstream infection in Gaza Strip is high (40 %) and mainly associated with the blaNDM-5-positive high-risk clone ST147.

Clinical Characteristics and Treatment Outcomes of Pediatric Drug-Resistant Mycoplasma pneumoniae Pneumonia in the Post-COVID-19 Era

Background

Mycoplasma pneumoniae pneumonia (MPP) is a prevalent disease among children. Typically, macrolides are the first-line treatment for MPP in China. However, the number of cases resistant to macrolides has been rising, especially after the outbreak of the COVID-19 pandemic, which has further complicated the clinical management of macrolide-unresponsive Mycoplasma pneumoniae pneumonia (MUMPP) in children.

Objective

This study examined the clinical characteristics of MUMPP and the effects of various treatments on children with MUMPP during March 2023 to February 2024 in southern China.

Methods

We conducted a retrospective case-control study at a university-affiliated hospital in southern China. Patients were categorized based on their response to macrolide treatment into two groups: MUMPP and control group. The study included 549 pediatric patients. Of these, 297 were in the MUMPP group and 252 were in the control group. This categorization allowed us to compare clinical characteristics and laboratory indicators between the groups. The MUMPP group received one of the three treatments: combined antibiotics, additional steroids, or a switch to doxycycline. Subsequently, we analyzed differences in clinical outcomes, which included hospital stay, hospital cost, and recovery time.

Results

No significant differences were found in gender or pre-admission disease duration between the MUMPP and control group (P>0.05). However, subjects in MUMPP group was older, had longer fever durations, extended hospital stays, higher medical costs, and elevated levels of C-reactive protein, lactate dehydrogenase, IL-6, and γ-IFN. All of which showed statistically significant differences (P<0.05). Within the MUMPP group, patients switched to doxycycline had the shortest hospital stay and recovery time, significantly differing from those in other treatment groups (P<0.05).

Conclusion

Children in the MUMPP group exhibited higher inflammatory indicators than the control group. The early adaptation of treatment strategies, particularly the switch to doxycycline, is associated with improved clinical outcomes.

Synthesis, Antimicrobial Activities, and Model of Action of Indolyl Derivatives Containing Amino-Guanidinium Moieties

The objectives of the study were to design, synthesize, and evaluate the antibacterial activity of a series of novel aminoguanidine-indole derivatives. Thirty-seven new compounds were effectively synthesized through nucleophilic substitution reaction and guanidinylation reaction. Chemical structures of all the desired compounds were identified by NMR and HR-MS spectroscopy. Most of the synthesized compounds showed significant antibacterial activity against ESKAPE pathogens and clinical resistant Klebsiella pneumoniae (K. pneumoniae) isolates. K. pneumoniae is an important opportunistic pathogen that often threatens the health of immunocompromised people such as the elderly, children, and ICU patients. The most active compound 4P showed rapid bactericidal activity against resistant K. pneumoniae 2108 with MIC and MBC values that were 4 and 8 µg/mL, respectively. The hemolytic activity of 4P was low, with an HC50 value of 123.6 µg/mL. Compound 4P induced the depolarization of the bacterial membrane and disrupted bacterial membrane integrity and was not prone to antibiotic resistance. The dihydrofolate reductase (DHFR) activity was also notably inhibited by 4P in vitro. Molecular docking revealed that the aminoguanidine moiety and indole structure of 4P played an important role in binding to the target site of the K. pneumoniae dihydrofolate reductase (DHFR) receptor. In the mouse pneumonia model caused by K. pneumoniae, 4P improved the survival rate of mice, reduced bacterial loads, and alleviated tissues' pathological injuries at a dosage of 4 mg/kg. Therefore, compound 4P may be a promising lead compound or drug candidate for antibacterial purposes against K. pneumoniae.

Elucidating Infectious Causes of Fever of Unknown Origin: A Laboratory-Based Observational Study of Patients with Suspected Ebola Virus Disease, Guinea, 2014

BACKGROUND

The etiology of fever of unknown origin (FUO) in sub-Saharan Africa often remains unexplained.

METHODS

We performed a retrospective laboratory-based observational study of 550 Guinean patients with FUO testing negative for Ebola virus from March to December 2014. Blood-borne pathogens were diagnosed by polymerase chain reaction (PCR) or reverse transcription-PCR (RT-PCR), serologic tests, and targeted and unbiased high-throughput sequencing (HTS).

RESULTS

In 275 of 550 individuals, we found evidence of ≥1 pathogen by molecular methods. We identified Plasmodium in 35.6% of patients via PCR, with P falciparum constituting 96.4% of these cases. Pathogenic bacteria, including Salmonella and Klebsiella, were detected in 18.4% of patients through PCR and HTS. Resistance determinants against first-line antibiotics were found in 26.9% of pooled sera by HTS. Yellow fever, Lassa, and Ebola viruses were detected in 5.8% of patients by RT-PCR; HTS-guided RT-PCR confirmed Orungo virus infection in 1 patient. Phylogenetic analyses revealed that the viral genomes matched the available genomic data in terms of location and time. Indirect immunofluorescence assays revealed immunoglobulin M antibodies against yellow fever, Ebola, dengue, West Nile, and Crimean Congo hemorrhagic fever viruses in 11 of 100 patients who were PCR or RT-PCR negative. One in 5 patients who were infected presented coinfections, predominantly malaria associated with sepsis-causing bacteria, in adults (12.1%) and children (12.5%), whereas viral coinfections were rare. Patients presented fever (74.7%), asthenia (67.7%), emesis (38.2%), diarrhea (28.3%), and hemorrhage (11.8%), without clear etiology associations.

CONCLUSIONS

An exhaustive laboratory investigation elucidated infectious causes of FUO in 52.3% of patients. Quality control and strengthening laboratory capacities in sub-Saharan Africa are essential for patient care, outbreak response, and regionally appropriate diagnostics.

Klebsiella pneumoniae bioconjugate vaccine functional durability in mice

Klebsiella pneumoniae is a leading cause of hospital-acquired infections as well as the leading cause of neonatal sepsis worldwide. Further, increasing antibiotic resistance in this pathogen makes K. pneumoniae troublesome to treat. Despite its clinical importance, there is not yet an approved K. pneumoniae vaccine available. Here we tested antibody durability and long-term functionality of two previously reported bioconjugate vaccines targeting the K. pneumoniae capsular type K2 and O-antigen type O1v1. We demonstrate that both antibodies are durable in mice for up to six months with significant IgG titers. However, only the K2 antibodies exhibit functionality out to six months as evidenced by serum bactericidal activity and survival in a murine bacteremia challenge model. These results are another promising step towards demonstrating the clinical capacity of bioconjugate vaccines and their induction of durable antibody responses.

Contribution of malnutrition to infant and child deaths in Sub-Saharan Africa and South Asia

INTRODUCTION

Malnutrition contributes to 45% of all childhood deaths globally, but these modelled estimates lack direct measurements in countries with high malnutrition and under-5 mortality rates. We investigated malnutrition's role in infant and child deaths in the Child Health and Mortality Prevention Surveillance (CHAMPS) network.

METHODS

We analysed CHAMPS data from seven sites (Bangladesh, Ethiopia, Kenya, Mali, Mozambique, Sierra Leone and South Africa) collected between 2016 and 2023. An expert panel assessed each death to determine whether malnutrition was an underlying, antecedent or immediate cause or other significant condition. Malnutrition was further classified based on postmortem anthropometry using WHO growth standards for underweight (z-scores for weight-for-age <-2), stunting (length-for-age <-2), and wasting (weight-for-length or MUAC Z-scores <-2).

RESULTS

Of 1601 infant and child deaths, malnutrition was considered a causal or significant condition in 632 (39.5%) cases, including 85 (13.4%) with HIV infection. Postmortem measurements indicated 90.1%, 61.2% and 94.1% of these cases were underweight, stunted and wasted, respectively. Most malnutrition-related deaths (n=632) had an infectious cause (89.1%). The adjusted odds of having malnutrition as causal or significant condition were 2.4 (95% CI 1.7 to 3.2) times higher for deaths involving infectious diseases compared with other causes. Common pathogens in the causal pathway for malnutrition-related deaths included Klebsiella pneumoniae (30.4%), Streptococcus pneumoniae (21.5%), Plasmodium falciparum (18.7%) and Escherichia coli/Shigella (17.2%).

CONCLUSION

Malnutrition was identified as a causal or significant factor in 39.5% of under-5 deaths in the CHAMPS network, often in combination with infectious diseases. These findings highlight the need for integrated interventions addressing both malnutrition and infectious diseases to effectively reduce under-5 mortality.

Etiologies and comorbidities of meningitis deaths in children under 5 years in high-mortality settings: Insights from the CHAMPS Network in the post-pneumococcal vaccine era

BACKGROUND

The role of meningitis in causing deaths and in children under 5 is unclear, especially since widespread use of vaccines to prevent common causes of meningitis. Child Health and Mortality Prevention Surveillance (CHAMPS) uses post-mortem minimally invasive tissue sampling (MITS) and ante-mortem data to explore death causes. We aimed to assess meningitis's contribution to mortality and identify causative pathogens in children under 5 within CHAMPS Network sites.

METHOD

In this observational study, we analyzed deaths in live-born children <5 years of age that occurred between December 16, 2016, and December 31, 2023, in CHAMPS catchments in six sub-Saharan African countries (Ethiopia, Kenya, Mali, Mozambique, Sierra Leone, South Africa) and Bangladesh. MITS was conducted within 24-72 h of death, including blood and cerebrospinal fluid (CSF) culture, multi-organism targeted nucleic acid amplification tests on blood, CSF and lung tissue, and histopathology of lung, liver and brain. Expert panels at each site reviewed data to attribute causes of death following ICD-10 standards.

RESULT

Meningitis was in the causal pathway for 7.0% (270/3857) of deaths; in 4.8% (13/270) meningitis was considered the underlying condition. Neonates accounted for 65.9% (178/270) and infants or children 34.1% (92/270). Among neonatal meningitis deaths, 55.6% (99/178) occurred ≥72 h post-hospital admission; and common pathogens were Acinetobacter baumannii (49.5%, 49/99; mainly from South Africa) and Klebsiella pneumoniae (40.4%, 40/99). Forty-four percent (79/178) of neonatal meningitis deaths were community-associated, primarily due to K. pneumoniae (35.4%, 28/79) and Escherichia coli (13.9%, 11/79). Among infant and child meningitis deaths, 43.5% (40/92) occurred ≥72 h post-admission; and common pathogens were K. pneumoniae (42.5%,17/40) and A. baumannii (17.5%, 7/40). Among community-associated meningitis deaths in infants and children (56.5%, 52/92), Streptococcus pneumoniae (34.6%, 18/52) and K. pneumoniae (19.2%, 10/52) were common pathogens. Pathogen prevalence varied by region.

CONCLUSION

Our study highlights meningitis as a significant contributor to under-5 mortality in low-middle-income countries. The prominent role of K. pneumoniae and A. baumannii, particularly in healthcare settings and specific regions, highlights the need for better infection control, targeted interventions, and more effective treatment strategies.

Combating biofilm-associated Klebsiella pneumoniae infections using a bovine microbial enzyme

The emergence of multidrug-resistant Klebsiella pneumoniae poses significant clinical challenges with limited treatment options. Biofilm is an important virulence factor of K. pneumoniae, serving as a protective barrier against antibiotics and the immune system. Here, we present the remarkable ability of a bovine microbial enzyme to prevent biofilm formation (IC50 2.50 μM) and degrade pre-formed K. pneumoniae biofilms (EC50 1.94 μM) by degrading the matrix polysaccharides. The treatment was effective against four different clinical K. pneumoniae isolates tested. Moreover, the enzyme significantly improved the biofilm sensitivity of a poorly performing broad-spectrum antibiotic, meropenem, and immune cells, resulting in facile biofilm clearance from the mouse wound infection. Notably, well-known powerful enzymes of the same class, cellulase, and α-amylase, were nearly inactive against the K. pneumoniae biofilms. The enzyme exhibited antibiofilm activity without showing toxicity to the mammalian and microbial cells, highlighting the potential of the enzyme for in vivo applications.

Neonatal Colonization With Antibiotic-Resistant Pathogens in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis

Importance

In low- and middle-income countries (LMICs), neonatal bacterial infections are mainly caused by Enterobacterales species and Staphylococcus aureus, which are also the leading causes of mortality directly attributable to antimicrobial resistance. As bacterial colonization often precedes infection, better knowledge of colonization is crucial to prevent antibiotic-resistant neonatal sepsis.

Objective

To synthesize current evidence on the prevalence of and factors associated with colonization with third-generation cephalosporin-resistant Enterobacterales (3GCRE), carbapenem-resistant Enterobacterales (CRE), and methicillin-resistant S aureus (MRSA) during the first 3 months of life in LMICs.

Data Sources

PubMed, Scopus, Web of Science, and the World Health Organization Global Index Medicus were searched for articles published from January 1, 2000, through July 29, 2024.

Study Selection

Included studies were conducted in LMICs and reported prevalence rates or factors associated with colonization with 3GCRE, CRE, or MRSA in neonates and infants up to 3 months of age. Outbreak reports were excluded.

Data Extraction and Synthesis

Data extraction and risk-of-bias assessment using a Joanna Briggs Institute tool were performed by 2 independent reviewers. Pooled prevalence for each pathogen was computed using a random-effects model. Reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline.

Main Outcomes and Measures

Prevalence of and factors associated with 3GCRE, CRE, and MRSA colonization.

Results

Of the 3147 articles identified in the search, 67 studies (51 for 3GCRE and CRE and 16 for MRSA) including 17 152 individuals were eligible. The pooled prevalence of 3GCRE colonization was 30.2% (95% CI, 21.4%-40.7%; τ2 = 1.48; I2 = 95.1%), varying from 18.2% (95% CI, 10.8%-29.1%) in nonhospitalized individuals to 48.2% (95% CI, 36.4%-60.2%) in hospitalized individuals. The prevalence of CRE colonization was 2.6% (95% CI, 0.7%-8.8%; τ2 = 7.79; I2 = 95.6%), while it was 2.7% (95% CI, 1.0%-6.7%; τ2 = 2.58; I2 = 93.5%) for MRSA. Increased risk of colonization with 3GCRE was associated with hospital birth (odds ratio [OR], 1.87; 95% CI, 1.33-2.64), neonatal antibiotic use (OR, 2.96; 95% CI, 1.43-6.11), and prolonged rupture of membranes (OR, 3.86; 95% CI, 2.19-6.84).

Conclusions and Relevance

In this systematic review and meta-analysis of antibiotic-resistant pathogen carriage in individuals aged 0 to 3 months, the pooled prevalence was substantial despite a limited exposure period. Although high heterogeneity between studies limited extrapolation of results, the findings highlight the need for further investigation to identify transmission routes and to design targeted and effective preventive measures.

High Prevalence of Carbapenem-resistant Klebsiella Pneumoniae in Fecal and Water Samples in Dhaka, Bangladesh

We evaluated Klebsiella pneumoniae (Kp) gut carriage in healthy, unrelated adults and children living in separate households in Dhaka, Bangladesh. Average Kp prevalence in stool samples ranged from 61% in young children (15/25) to 81% in adults (21/26), with significantly higher abundance in adults (P = .03, t-test). Kp was also prevalent in household water (64%, 21/33) and standing water (85%, 23/27). The presence of Kp in household water was not strongly linked to stool Kp abundance among household members. Antimicrobial resistance was notable: 9% (6/69) of stool and 16% (7/44) of water isolates exhibited multidrug resistance. Carbapenem resistance was observed in 12% of stool isolates (8/69) and 14% of water isolates (6/44). These findings underscore the commonality of Kp in human and environmental reservoirs in Dhaka, Bangladesh, and highlight the emergence of drug-resistant Kp beyond healthcare settings.

Heptavalent O-Antigen Bioconjugate Vaccine Exhibiting Differential Functional Antibody Responses Against Diverse Klebsiella pneumoniae Isolates

Klebsiella pneumoniae is the leading cause of neonatal sepsis and is increasingly difficult to treat owing to antibiotic resistance. Vaccination represents a tractable approach to combat this resistant bacterium; however, there is currently not a licensed vaccine. Surface polysaccharides, including O-antigens of lipopolysaccharide, have long been attractive candidates for vaccine inclusion. Herein we describe the generation of a bioconjugate vaccine targeting 7 predominant O-antigen subtypes in K. pneumoniae. Each bioconjugate was immunogenic in isolation, with limited cross-reactivity among subtypes. Vaccine-induced antibodies demonstrated varying degrees of binding to a wide variety of K. pneumoniae strains. Furthermore, serum from vaccinated mice induced complement-mediated killing of many of these strains. Finally, increased capsule interfered with the ability of O-antigen antibodies to bind and mediate killing of some K. pneumoniae strains. Taken together, these data indicate that this novel heptavalent O-antigen bioconjugate vaccine formulation exhibits limited efficacy against some, but not all, K. pneumoniae isolates.

Yoyo Dieting, Post-Obesity Weight Loss, and Their Relationship with Gut Health

Excessive body weight is associated with many chronic metabolic diseases and weight loss, so far, remains the gold standard treatment. However, despite tremendous efforts exploring optimal treatments for obesity, many individuals find losing weight and maintaining a healthy body weight difficult. Weight loss is often not sustainable resulting in weight regain and subsequent efforts to lose weight. This cyclic pattern of weight loss and regain is termed "yoyo dieting" and predisposes individuals to obesity and metabolic comorbidities. How yoyo dieting might worsen obesity complications during the weight recurrence phase remains unclear. In particular, there is limited data on the role of the gut microbiome in yoyo dieting. Gut health distress, especially gut inflammation and microbiome perturbation, is strongly associated with metabolic dysfunction and disturbance of energy homeostasis in obesity. In this review, we summarise current evidence of the crosstalk between the gastrointestinal system and energy balance, and the effects of yoyo dieting on gut inflammation and gut microbiota reshaping. Finally, we focus on the potential effects of post-dieting weight loss in improving gut health and identify current knowledge gaps within the field, including gut-derived peptide hormones and their potential suitability as targets to combat weight regain, and how yoyo dieting and associated changes in the microbiome affect the gut barrier and the enteric nervous system, which largely remain to be determined.