Multidrug resistance pattern and molecular epidemiology of pathogens among children with diarrhea in Bangladesh, 2019-2021

Prevalence of Salmonella and Shigella species and their multidrug resistance patterns among pediatric populations in Ethiopia: a systematic review and meta-analysis

BACKGROUND

Salmonella and Shigella are major enteric pathogens that cause diarrhea in children worldwide. They are pathogenic microbes that cause significant diarrheal morbidity and mortality in under five children in resource limited countries. Thus, this systemic review and meta-analysis aimed to investigate the prevalence of Salmonella and Shigella species and their multidrug resistance patterns in pediatric populations in Ethiopia.

METHODS

The articles were searched extensively in the electronic databases and grey literature using entry terms or phrases. Studies meeting the eligibility criteria were extracted in MS Excel and exported for statistical analysis into STATA version 14 software. The overall pooled prevalence of Salmonella and Shigella species was computed using a random-effects model. Heterogeneity was assessed using the Cochrane Q test and I2 statistics with corresponding p-values. Publication bias was assessed using a funnel plot and Egger's test. In addition, sensitivity analysis was performed to determine the impact of individual studies on the pooled effect size.

RESULT

Of a total of 742 identified studies, 89 studies were eligible for full-text analysis. Of 89 studies, 21 were included for meta-analysis involving 5318 study participants. These eligible studies reported a total of 593 bacterial isolates. The overall pooled prevalence of Salmonella and Shigella among pediatrics in Ethiopia was 10.70% (95% CI: 8.96-12.45), with substantial heterogeneity (I2 = 82.1%, p < 0.001) across the studies. The pooled prevalence of Salmonella and Shigella individually among pediatrics in Ethiopia was 15.43% (95% CI: 10.42-20.72) and 15.83% (95% CI: 11.40-20.40), respectively. Moreover, the overall prevalence of multidrug resistance in Salmonella and Shigella isolates was 81.03% (95% CI: 77.39-84.67) with substantial heterogeneity of I2 of 95%, p < 0.0001 between the pooled prevalence of the two species.

CONCLUSION

The pooled prevalence of Salmonella and Shigella and their multidrug resistance were alarmingly high in pediatric. The initial empirical treatment of pediatrics patients remains challenging and results high prevalence of antimicrobial resistance. Thus, appropriate infection prevention and control strategies should be implemented and treatment should be directed based on antimicrobial stewardship protocols.

Multidrug-resistant ST11-KL64 hypervirulent Klebsiella pneumoniae with multiple bla- genes isolated from children's blood

Introduction

Hypervirulent carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) poses an increasing public health risk due to its high treatment difficulty and associated mortality, especially in bone marrow transplant (BMT) patients. The emergence of strains with multiple resistance mechanisms further complicates the management of these infections.

Methods

We isolated and characterized a novel ST11-KL64 hv-CRKP strain from a pediatric bone marrow transplantation patient. Antimicrobial susceptibility testing was performed to determine resistance patterns. Comprehensive genomic analysis was conducted to identify plasmid types, virulence factors, and antimicrobial resistance genes, as well as potential resistance mechanisms associated with mutations and plasmid-mediated variants.

Results

The isolated hv-CRKP strain exhibited multidrug resistance to carbapenem, tigecycline, and polymyxin. Genomic analysis revealed that the IncHI1B/repB plasmid carried virulence factors (rmpA, ΔrmpA2, iucABCD, iutA), while IncFII/IncR and IncFII plasmids harbored resistance genes [bla C T X - M - 6 5 , bla T E M - 1 B , rmtB, bla S H V - 1 2 , bla K P C - 2 , qnrS1, bla L A P - 2 , sul2, dfrA14, tet(A), tet(R)]. The coexistence of bla C T X - M - 6 5 , bla T E M - 1 B , bla S H V - 1 2 , bla L A P - 2 ,and bla K P C - 2 in one hv-CRKP strain is exceptionally rare. Additionally, the Tet(A)-S251A variant in the conjugative plasmid pTET-4 may confer tigecycline resistance. Mutations in MgrB, PhoPQ, and PmrABCDK were identified as potential contributors to increased polymyxin resistance. Interestingly, plasmid-encoded restriction-modification systems and Retron regions were identified, which could potentially confer phage resistance.

Discussion

The combination of virulence and antimicrobial resistance factors in the ST11-KL64 hv-CRKP strain represents a significant challenge for treating immunocompromised pediatric patients. Particularly concerning is the resistance to polymyxin and tigecycline, which are often last-resort treatments for multidrug-resistant infections. The findings highlight the urgent need for effective surveillance, infection control measures, and novel therapeutic strategies to manage such hypervirulent and multidrug-resistant pathogens.

Global prevalence patterns and distribution of Vibrio cholerae: A systematic review and meta-analysis of 176,740 samples

This global systematic review and meta-analysis of Vibrio cholerae prevalence, covering environmental, food, animal, and human samples, analysed 111 studies from five databases. The meta-analysis, adhering to standard reporting guidelines, revealed a pooled prevalence of 10.6 % (95 % CI; 8.2 - 13.5; I2 = 99.595 %, p < 0.001) from 176,740 samples, including 27,219 cholera cases. Despite significant publication bias (Egger's test, p = 0.00018), prevalence estimate remained stable in leave-one-out analysis. Subgroup analysis showed prevalence varied by region, with Indonesia highest (55.2 %) and Jordan lowest (0.2 %). Asia continent had the highest prevalence (13.9 %), followed by South America (12.1 %), and lowest in Europe (3.8 %). Environmental samples exhibited the highest prevalence (24.9 %), while human samples had the lowest (7.1 %). The pervasive presence of V. cholerae in environmental resources highlights the persistent risk of global cholera outbreaks, necessitating urgent proactive measures and ongoing surveillance for effective cholera control.

Safety and Immunogenicity of a 4-Component Generalized Modules for Membrane Antigens Shigella Vaccine in Healthy European Adults: Randomized, Phase 1/2 Study

BACKGROUND

We report data from stage 1 of an ongoing 2-staged, phase 1/2 randomized clinical trial with a 4-component generalized modules for membrane antigens-based vaccine against Shigella sonnei and Shigella flexneri 1b, 2a, and 3a (altSonflex1-2-3; GSK).

METHODS

Europeans aged 18-50 years (N = 102) were randomized (2:1) to receive 2 injections of altSonflex1-2-3 or placebo at 3- or 6-month interval. Safety and immunogenicity were assessed at prespecified time points.

RESULTS

The most common solicited administration-site event (until 7 days after each injection) and unsolicited adverse event (until 28 days after each injection) were pain (altSonflex1-2-3, 97.1%; placebo, 58.8%) and headache (32.4%; 23.5%), respectively. All serotype-specific functional IgG antibodies peaked 14-28 days after injection 1 and remained substantially higher than prevaccination at 3 or 6 months postvaccination; the second injection did not boost but restored the initial immune response. The highest seroresponse rates (≥4-fold increase in titers over baseline) were obtained against S. flexneri 2a (enzyme-linked immunosorbent assay [ELISA] after injection 1, 91.0%; after injection 2 [day 113; day 197], 100%; 97.0% and serum bactericidal activity [SBA] after injection 1, 94.4%; after injection 2, 85.7%; 88.9%) followed by S. sonnei (ELISA after injection 1, 77.6%; after injection 2, 84.6%; 78.8% and SBA after injection 1, 83.3%; after injection 2, 71.4%; 88.9%). Immune responses against S. flexneri 1b and S. flexneri 3a, as measured by both ELISA and SBA, were numerically lower compared to those against S. sonnei and S. flexneri 2a.

CONCLUSIONS

No safety signals or concerns were identified. altSonflex1-2-3 induced functional serotype-specific immune responses, allowing further clinical development in the target population. Clinical Trials Registration . NCT05073003.

Epidemiological pattern and genomic insights into multidrug-resistant ST491 Acinetobacter baumannii BD20 isolated from an infected wound in Bangladesh: Concerning co-occurrence of three classes of beta lactamase genes

OBJECTIVE

Multidrug-resistant (MDR) Acinetobacter baumannii is a major issue within healthcare facilities in Bangladesh due to its frequent association with hospital-acquired infections. In this study we report on a carbapenem-resistant draft genome sequence of an A. baumannii BD20 sample isolated from an infected wound in Bangladesh.

METHODS

A. baumannii BD20 was isolated from an infected burn wound. Whole-genome sequencing was carried out and annotated using PGAP and Prokka. Sequence type, antimicrobial resistance genes, virulence factor genes, and metal resistance genes were investigated. Core genome multilocus sequence typing-based phylogenomic analysis between A. baumannii BD20 and 213 A. baumannii strains retrieved from the NCBI GenBank database was performed using the BacWGSTdb 2.0 server.

RESULTS

A. baumannii BD20 (MLST 491) was resistant to all the antibiotics tested, except for colistin and polymyxin B. Along with many other antibiotic resistance genes, the isolate harbored three classes of beta lactamase-producing genes: blaGES-11 (class A), blaOXA-69 (class D), blaADC-10 (class C), and blaADC-11 (class C). Additionally, the strain carried several virulence genes and metal resistance determinants, which may contribute to its increased virulence. Core genome MLST-based phylogenomic analysis revealed that A. baumannii BD20 was closely related to another ST491 strain isolated from Singapore.

CONCLUSIONS

The findings of this study underscore the growing challenge of MDR A. baumannii, emphasizing the need for vigilant surveillance and infection-control measures in healthcare settings in order to address these emerging threats effectively.

Isolation, Genomic Characterization of Shigella prophage fPSFA that effectively infects multi-drug resistant Shigella isolates from the Indian Poultry Sector

Because of uncontrolled use of antibiotics, emergence of multidrug-resistant Shigella species poses a huge potential of zoonotic transfer from poultry sector. With increasing resistance to current antibiotics, there is a critical need to explore antibiotic alternatives. Using a Shigella flexneri reference strain, we isolated a novel fPSFA phage after inducing with mitomycin C. The phage was found to be stable for wide ranges of temperature -20 °C-65 °C and pH 3 to 11. fPSFA shows a latent period that ranges from 20 to 30 min and generation times of 50-60 min. The genome analysis of phage reveals two major contigs of 23788 bp and 23285 bp with 50.16 % and 39.33 % G + C content containing a total of 80 CDS and 2 tRNA genes. The phage belongs to Straboviridae family and lacks any virulence or antimicrobial resistance gene, thus making it a suitable candidate for treatment of drug-resistant infections. To confirm lytic ability of novel phage, we isolated 54 multidrug-resistant Shigella species from thirty-five poultry fecal samples that shows multiple antibiotic resistance index ranging from 0.15 to 0.75 (from 3 Indian states). The fPSFA showed lytic activity against multidrug-resistant Shigella isolates (73.08 %) (MARI≥0.50). The wide host ranges of fPSFA phage demonstrate its potential to be used as a biocontrol agent.

Molecular Signature of Monocytes Shaped by the Shigella sonnei 1790-Generalized Modules for Membrane Antigens Vaccine

Shigellosis, an acute gastroenteritis infection caused by Shigella species, remains a public health burden in developing countries. Recently, many outbreaks due to Shigella sonnei multidrug-resistant strains have been reported in high-income countries, and the lack of an effective vaccine represents a major hurdle to counteract this bacterial pathogen. Vaccine candidates against Shigella sonnei are under clinical development, including a Generalized Modules for Membrane Antigens (GMMA)-based vaccine. The mechanisms by which GMMA-based vaccines interact and activate human immune cells remain elusive. Our previous study provided the first evidence that both adaptive and innate immune cells are targeted and functionally shaped by the GMMA-based vaccine. Here, flow cytometry and confocal microscopy analysis allowed us to identify monocytes as the main target population interacting with the S. sonnei 1790-GMMA vaccine on human peripheral blood. In addition, transcriptomic analysis of this cell population revealed a molecular signature induced by 1790-GMMA mostly correlated with the inflammatory response and cytokine-induced processes. This also impacts the expression of genes associated with macrophages' differentiation and T cell regulation, suggesting a dual function for this vaccine platform both as an antigen carrier and as a regulator of immune cell activation and differentiation.