Search Results (114)

Antibiotic-resistant Pseudomonas aeruginosa presents a critical global health challenge, particularly in hospital-acquired infections. Bacteriophages offer a promising therapeutic avenue due to their ability to target and lyse resistant strains. This study characterizes Pseudomonas phage Banzai, a newly isolated Pbunavirus (family Lindbergviridae) with lytic activity against multiple P. aeruginosa isolates, including multidrug-resistant strains. Genomic analysis revealed a 66,189 bp genome, lacking antibiotic resistance or virulence factors, and suggested a headful packaging mechanism and the presence of a bidirectional component in the replication. In vivo experiments using Galleria mellonella showed therapeutic potential, significantly improving larval survival (87% at 24 h). Host range analysis revealed activity against 13 of 30 P. aeruginosa isolates, including members of O1, O3, O5 and O6 in silico predicted serogroups. Phylogenomic analyses place phage Banzai within the genus Pbunavirus, sharing 94.8% intergenomic similarity with its closest relatives, supporting its classification as a novel species. These findings highlight phage Banzai as a potential candidate for phage therapy, demonstrating genomic stability, a strictly lytic lifestyle, and in vivo efficacy. Full article

In the past two decades, Shiga toxin-producing Escherichia coli (STEC) has been responsible for multiple large-scale outbreaks worldwide, affecting thousands of individuals. While surveillance systems in developed countries such as the United States, the United Kingdom, Europe, Australia, Japan, and Canada are well-established, data on STEC prevalence in developing nations remain sparse, partly due to the absence of well-structured molecular diagnostic networks or surveillance systems. This review analyzed 250 studies published between 2014 and 2024 across 39 developing countries in Africa, Asia, Latin America, and the Caribbean, yielding 8986 STEC isolates. Detailed serogroup and serotype data were available for 55.9% of these, with O111, O157, and O26 being most common in humans. In animals, O157:H7 was most frequent, while food isolates mirrored global trends with O157 and O111 dominance. Notably, O145, a serogroup frequently reported in the U.S. and Europe, was absent from the ‘’Top Seven’’ serogroups. Shiga toxin subtypes stx1a and stx2a were most prevalent in human cases. In animal isolates, stx2e was the most prevalent subtype, while stx2c was most commonly found in food samples. We recommend establishing reference laboratories in these regions to improve data quality, strengthen monitoring efforts, and reduce the burden of STEC infections globally. Full article

Avian pathogenic Escherichia coli (APEC) causes avian colibacillosis, leading to significant economic losses and concerns for food safety in the poultry industry. This study focused on examining the virulence gene profile, antibiotic resistance prevalence, and resistance patterns of APEC isolates. A total of 250 bacterial strains were collected from birds affected by colibacillosis. Serogrouping revealed diverse serotypes, with O2 being the most common (16%), followed by O1, O8, and O76. All isolates tested positive for at minimum one virulence gene, with 7.2% carrying all five targeted genes, particularly in serogroups O1, O8, O45, and O88. The most detected gene was iss, present in 79.6% of isolates, followed by tsh, iucC, sitA, and papC. The antibiotic resistance analysis showed that all isolates exhibited multidrug resistance, although they remained susceptible to gentamicin, amikacin, ciprofloxacin, and chloramphenicol. Moreover, specific antibiotic resistance genes were known in the isolates, with tetA detected in 54.8%, tetB in 51.7%, sul1 in 50%, and aadA1 in 29.2%. These findings highlight the widespread antibiotic resistance in chicken carcasses, which poses a hazard to human health in terms of transfer of resistance to humans, reduced effectiveness of antibiotics and impaired ability to contain infectious diseases. Therefore, it is crucial to implement strict monitoring programs to regulate antibiotic usage in poultry production. Full article

An African Swine Fever (ASF) outbreak was first recorded in the Philippines in July 2019. Since then, the disease has spread across provinces in Luzon, Visayas, and Mindanao, causing severe economic consequences for the country’s swine industry. Here, we report the genome sequencing of ASF virus strains from outbreaks in several provinces of the Philippines between 2021 and 2023, using a long-read tiled amplicon sequencing approach. The coding-complete genomes generated ranged from 187,609 to 189,540 bp in length, with GC contents of 38.4% to 38.5%. Notably, a strain from the Bataan province had a 1.9 kb deletion at the 5′-end, affecting several coding regions. The strains were characterized using 13 genes and regions; namely the B646L gene, the CD2v serogroup, the central variable region (CVR) of the B602L gene, the intergenic region (IGR) between the I73R and I329L genes, the IGR between A179L and A137R, O174L, K145R, Bt/Sj, J268L, and ECO2, the multigene family (MGF) 505-5R, and the MGF 505-9R and 10R regions. The ASFV strains were mostly related to Asian and European p72 genotype II strains. Genetic profiling provides valuable information on the diversity of local strains of ASFV in the Philippines, which are useful for epidemiology, diagnostics, and vaccine development. Full article

Non-O1, non-O139 Vibrio cholerae (NOVC) extraintestinal infections are rare, but recently, several clinical incidents have been reported worldwide. Toxigenic V. cholerae is a well-known etiological agent of cholera, responsible for acute dehydrating watery diarrhea. Outbreaks occur in an epidemic seasonal pattern, particularly in countries with poverty and poor sanitation. Strains of NOVC are usually not involved in causing the epidemic or pandemic outbreaks seen with potential strains of V. cholerae serogroup O1 and O139. However, they can still cause severe sporadic cases of intestinal as well as extraintestinal infections. In this study, we investigated a case of extraintestinal infections associated with the NOVC serogroup isolated from a deep closed wound abscess. The isolate was screened for the presence of three major virulence genes, toxR, ctxA, and tcpA. The strain tested positive for the toxR gene encoding the regulatory protein and cholera toxin (ctx) gene and tested negative for the toxin-coregulated pilus (TCP) gene, which is essential for the colonization of the human intestine, causing the severe diarrheal disease cholera. To the best of our knowledge, this is the first case of extraintestinal infection caused by toxigenic Vibrio cholerae non-O1/non-O139 in a hospitalized patient in Saudi Arabia. Full article

Avian colibacillosis caused by avian pathogenic Escherichia coli (APEC) strains is a bacterial disease responsible for enormous economic losses in the poultry industry, due to high mortality rates in farms, antibiotic therapy costs, and seizures at slaughterhouses. The aim of this study was to characterize the serogroups and molecular features of extended spectrum β-lactamase (ESBL)-producing APEC isolates recovered from 248 liver samples of 215 broilers and 33 turkeys with colibacillosis lesions in northeast Algeria. For this, microbiological tests were carried out, according to the recommended standards: E. coli isolates were recovered using standard microbiological protocols, and identification was carried out by MALDI-TOF MS. Serogrouping was performed using a rapid agglutination slide and the antisera of three O somatic groups (O1, O2, O78). Antimicrobial susceptibility was determined by the disk diffusion method. PCR assays and sequencing were used to detect antimicrobial resistance genes, integrons, phylogrouping, and MLST. Conjugation experiments were also conducted to determine the transferability of the retrieved ESBL-encoding genes. Overall, 211 (85.1%) APEC isolates were collected (one per positive sample), and 164 (77.7%) of them were typable. The O2 and O1 serogroups were the most detected (46.1% in broiler typable isolates and 61.5% in turkey typable isolates). Seventeen APEC isolates were ESBL-producers and harbored the following genes (number of isolates): bla_CTX-M-1 (14), bla_CTX-M-15 (2), and bla_SHV-12 (1). They belonged to phylogroups D (10 isolates), B1 (6 isolates), and B2 (1 isolate). The MLST of 13 ESBL producers revealed seven STs: ST23, ST38, ST48, ST117, ST131, ST1146, and ST5087. The ESBL-encoding genes were transferred by conjugation among 15 ESBL-producing isolates, and transconjugants acquired either the IncK or IncI1 plasmids. Concerted efforts from all poultry actors are needed to establish surveillance monitoring strategies to mitigate the spread of ESBL-producing isolates implicated in avian colibacillosis. Full article

Background: Escherichia coli is one of the most studied bacteria worldwide due to its genetic plasticity. Recently, in addition to characterizing its pathogenic potential, research has focused on understanding its resistance profile to inhibitory agents, whether these be antibiotics or sanitizers. Objectives: The present study aimed to investigate six of the main serogroups of foodborne infection (O26, O45, O103, O111, O121, and O157) and to understand the dynamics of heterogeneity in resistance to sanitizers derived from quaternary ammonium compounds (QACs) and peracetic acid (PAA) using whole-genome sequencing (WGS). Methods: Twenty-four E. coli strains with varied resistance profiles to QACs and PAA were analyzed by WGS using NovaSeq6000 (150 bp Paired End reads). Bioinformatic analyses included genome assembly (Shovill), annotation via Prokka, antimicrobial resistance gene identification using Abricate, and core-genome analysis using Roary. A multifactorial multiple correspondence analysis (MCA) was conducted to explore gene–sanitizer relationships. In addition, a large-scale analysis utilizing the NCBI Pathogen Detection database involved a 2 × 2 chi-square test to examine associations between the presence of qac and stx genes. Results: The isolates exhibited varying antimicrobial resistance profiles, with O45 and O157 being the most resistant serogroups. In addition, the qac gene was identified in only one strain (S22), while four other strains carried the stx gene. Through multifactorial multiple correspondence analysis, the results obtained indicated that strains harboring genes encoding Shiga toxin (stx) presented profiles that were more likely to be sensitive to QACs. To further confirm these results, we analyzed 393,216 E. coli genomes from the NCBI Pathogen Detection database. Our results revealed a significant association (p < 0.001) between the presence of qac genes and the absence of stx1, stx2, or both toxin genes. Conclusion: Our findings highlight the complexity of bacterial resistance mechanisms and suggest that non-pathogenic strains may exhibit greater tolerance to QAC sanitizer than those carrying pathogenicity genes, particularly Shiga toxin genes. Full article

Food safety, particularly within the meat industry, is a significant concern addressed under the One Health concept, emphasizing the necessity of enhanced surveillance and hygiene protocols to mitigate contamination risks. This study assessed microbiological risks in Romanian bovine slaughterhouses by analyzing 150 samples from stool and carcasses at the post-evisceration and cooling stages over seven months in two abattoirs, using standardized microbiological methods and PCR to quantify aerobic colony counts (ACCs), Enterobacteriaceae, and pathogens (E. coli, Salmonella spp., and Listeria spp.). ACCs and Enterobacteriaceae levels decreased significantly [p < 0.05] during processing, highlighting effective hygiene measures. Pathogenic E. coli was identified in 14% of fecal samples and 5% of carcasses, indicating cross-contamination risks. Salmonella spp. were found in 28% of fecal samples but absent on carcasses, suggesting successful containment. Listeria spp. were rare and not detected on carcasses. PCR confirmed the presence of pathogenic strains in stool samples, emphasizing the need for strict hygiene practices and regular monitoring to improve meat safety and protect public health. In conclusion, the prevalence of E. coli, particularly serogroups like O101 and O26, and the absence of Salmonella and Listeria in carcass samples reflect both regional differences in pathogenic strains and the need for comprehensive, multi-stage control measures. Further studies should broaden pathogen surveillance to include more E. coli serogroups and implement stricter hygiene protocols to prevent cross-contamination during evisceration, skinning, and cooling. Regular monitoring of Salmonella and Listeria, especially in silage-fed cattle regions, along with improved coordination across the food production, health, and environmental sectors, is essential to mitigate contamination risks and safeguard public health. Full article

Contamination of beef by certain strains of Shiga toxin-producing Escherichia coli (STEC) called enterohemorrhagic E. coli (EHEC) can lead to outbreaks of severe disease. Therefore, accurate monitoring tests are needed to identify high risk beef products and divert them from consumers. Most EHEC testing focuses on the detection of their key virulence factors Shiga toxin (stx) and intimin (eae). However, these two factors can occur separately in lower risk nonpathogenic E. coli (STEC and enteropathogenic E. coli; EPEC) and confound testing if both are present. Accessory virulence factors like the Type III secreted effectors espK and espV may aid in increasing the specificity of EHEC testing. This work first evaluated collections of EHEC (n = 83), STEC (n = 100) and EPEC (n = 95), finding espK and/or espV in 100%, 0%, and 60% of each, respectively. Next, an inoculation study of beef trim samples (n = 118) examined the ability of including espK and espV in the monitoring test scheme to distinguish samples inoculated with EHEC from those inoculated with mixtures of STEC and EPEC (non-EHEC). Test accuracy was calculated as Area Under the Receiver Operating Characteristic curve (AUC) and found to be significantly (p < 0.05) different, increasing from 68.0% (stx/eae) to 76.8% by including espK and espV. Finally, 361 regulatory agency beef samples that had been identified as suspect for EHEC (stx+/eae+) were examined with the addition of espK and espV, and results compared to culture isolation. Culture isolation identified 42 EHEC, 82 STEC, and 67 EPEC isolates in 146 of the samples. In the case of these naturally contaminated samples, inclusion of espK and espV increased test accuracy compared to culture isolation from an AUC of 50.5% (random agreement) to 69.8% (good agreement). Results show that the inclusion of espK and espV can increase the specificity of identifying high risk EHEC contaminated beef and release beef contaminated with nonpathogenic or low risk E. coli. Further, use of espK and espV identified samples contaminated by common EHEC of serogroups O157, O26, and O103, as well as of less common serogroups O182, O177, and O5. Full article

Background/Objectives: Antimicrobial resistance of the E. coli O25 ST131 clonal lineage poses a significant therapeutic challenge worldwide, often involving resistance to fluoroquinolones and extended-spectrum beta-lactamase (ESBL) production. This retrospective study compared the dissemination of multidrug-resistant E. coli O25 ST131 isolated from the urine of outpatients at the largest Croatian clinical microbiology department across six years over two study periods. Methods: The E. coli O25 ST131 clonal lineage was detected via a rapid PCR method using pabB and trpA primers after positive agglutination with E. coli serogroup O25 antisera. ESBL phenotypes and antibiotic susceptibility were investigated according to EUCAST guidelines and breakpoint tables. Results: In the first period, there were a total of 45 isolates of E. coli O25 ST131, among which 30 were isolates with proven ESBL production. In the second period, a total of 114 isolates of E. coli O25 ST131 were detected, among which 75 (65.8%) were ESBL-positive (p > 0.05). In ESBL-negative strains, the multidrug-resistant (MDR) phenotype was characterized by simultaneous resistance to ampicillin, co-trimoxazole, and fluoroquinolones (with an equal proportion of 3/15 isolates in the first period and 7/39 isolates in the second period, p > 0.05). There was no statistically significant difference in the frequency of MDR detection across the two study periods (36/45 and 98/114, p > 0.05). This is the first detection of E. coli O25 ST131 in the outpatient population in Zagreb. Conclusions: There was no statistically significant difference in the frequency of detecting the E. coli O25 ST 131 clone across the two study periods. The high frequency of MDR phenotype among ESBL-negative isolates of E. coli O25 ST131 and an equally high proportion of MDR strains among ESBL producers in this clonal lineage, with the total detection of MDR isolates ≥ 80% in both study periods, are the reasons why this bacterial clone poses a public health threat and why further investigation into its metabolic and virulence characteristics is needed in order to estimate its spreading potential among the outpatient population in Zagreb. Full article

Background: Phage tail-like bacteriocins, or tailocins, provide a competitive advantage to producer cells by killing closely related bacteria. Morphologically similar to headless phages, their narrow target specificity is determined by receptor-binding proteins (RBPs). While RBP engineering has been used to alter the target range of a selected R2 tailocin from Pseudomonas aeruginosa, the process is labor-intensive, limiting broader application. Methods: We introduce a VersaTile-driven R2 tailocin engineering and screening platform to scale up RBP grafting. Results: This platform achieved three key milestones: (I) engineering R2 tailocins specific to Escherichia coli serogroups O26, O103, O104, O111, O145, O146, and O157; (II) reprogramming R2 tailocins to target, for the first time, the capsule and a new species, specifically the capsular serotype K1 of E. coli and K11 and K63 of Klebsiella pneumoniae; (III) creating the first bivalent tailocin with a branched RBP and cross-species activity, effective against both E. coli K1 and K. pneumoniae K11. Over 90% of engineered tailocins were effective, with clear pathways for further optimization identified. Conclusions: This work lays the groundwork for a scalable platform for the development of engineered tailocins, marking an important step towards making R2 tailocins a practical therapeutic tool for targeted bacterial infections. Full article

Bacteria from the genus Proteus are facultative human pathogens, primarily attacking the urinary tract and wounds. A total of 85 O serogroups have been identified so far among these bacilli. P. mirabilis Bprz 86 was isolated from the fistula of a patient in Łódź, Poland. Enzyme-Linked Immunosorbent Assay (ELISA) and Western blotting studies involving the P. mirabilis Bprz 86 lipopolysaccharide (LPS) and the strain-specific rabbit antiserum indicated that the strain, which does not belong to any of the O1–O85 serogroups, shares a common epitope with Proteus O17 antigens and is identical to another clinical P. mirabilis strain, Sm 120, isolated from the urine of a patient in the area. The O-specific polysaccharide (O antigen) was obtained from P. mirabilis Bprz 86 LPS through mild acid degradation, and the six-constituent structure of its repeating unit was determined using chemical analyses and 1D and 2D ¹H and ¹³C Nuclear Magnetic Resonance (NMR) spectroscopy. It includes (R)-3-hydroxybutanoyl, which, along with fucosamine and glucose residues, forms a fragment also present in the O17 antigens. Based on the obtained serological and chemical data, the two studied P. mirabilis isolates were proposed as candidates for a new successive O serogroup in the genus Proteus, O86. Full article

Cholera is linked to penury, making low- and middle-income countries (LMICs) particularly vulnerable to outbreaks. In this systematic review, we analyzed the drivers contributing to these outbreaks, focusing on the epidemiology of cholera in LMICs. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in PROSPERO (ID: CRD42024591613). We searched PubMed, Scopus, Web of Science, and Google Scholar to include studies on cholera outbreaks that occurred in LMICs from 1 January 2014 to 21 September 2024. Studies on outbreaks outside LMICs and focusing on sporadic cases were excluded. The risk of bias among included studies was assessed using a modified Downes et al. appraisal tool. Thematic analysis was used to synthesize the qualitative data, and meta-analyses to estimate the pooled prevalence. From 1662 records, 95 studies met inclusion criteria, primarily documenting outbreaks in Africa (74%) and Asia (26%). Contaminated water was the main route of disease transmission. The pooled fatality prevalence was 1.3% (95% CI: 1.1–1.6), and the detection rate among suspected cases was 57.8% (95% CI: 49.2–66.4). Vibrio cholerae O1 was the dominant serogroup while Ogawa was the dominant serotype. All studies reporting biotypes indicated El Tor. Although the isolates were 100% susceptible to ofloxacin, levofloxacin, norfloxacin, cefuroxime, and doxycycline, they were also fully resistant to amikacin, sulfamethoxazole, trimethoprim, and furazolidone. The persistence of cholera outbreaks in destitute areas with limited access to clean water and sanitation emphasizes the need for socioeconomic improvements, infrastructure development, and ongoing surveillance to support timely responses and achieve long-term prevention. Full article

Outer membrane vesicles (OMVs) are extracellular structures, ranging in size from 10 to 300 nm, produced by Gram-negative bacteria. They can be incorporated into the outer membrane of a recipient’s cells, which may enable the transfer of substances with lytic properties. Due to the scarce information regarding the OMVs produced by Proteus mirabilis, the aim of this study was to test the blebbing abilities of the clinical P. mirabilis O77 and O78 strains and to determine the blebs’ interactions with bacterial cells, including their possible bactericidal activities. The production of OMVs was visualised by Transmission electron microscopy (TEM). The presence of OMVs in the obtained samples as well as the phenomenon of OMV fusion to recipient cells were confirmed by Enzyme-Linked ImmunoSorbent Assay (ELISA) and Western blotting assays. The bacteriolytic activity of the OMVs was examined against P. mirabilis clinical strains and reference Staphylococcus aureus and Escherichia coli strains. It was shown that each of the two tested P. mirabilis strains could produce OMVs which were able to fuse into the cells of the other strain. The lytic properties of the O78 OMVs against another P. mirabilis O78 strain were also demonstrated. This promising result may help in the future to better understand the mechanisms of the pathogenesis and to treat the infections caused by P. mirabilis. Full article

Acute hepatopancreatic necrosis disease (AHPND) is one of the most important diseases in the global shrimp industry. The emergence of mutant AHPND-associated V. parahaemolyticus (Vp_AHPND) strains has raised concerns regarding potential misdiagnosis and unforeseen pathogenicity. In this study, we report the first emergence of a type II (pirA⁻, pirB⁺) natural mutant, Vp_AHPND (strain 20-082A3), isolated from cultured Penaeus vannamei in Korea. Phenotypic and genetic analyses revealed a close relationship between the mutant strain 20-082A3 and the virulent Korean Vp_AHPND strain 19-021-D1, which caused an outbreak in 2019. Detailed sequence analysis of AHPND-associated plasmids showed that plasmid pVp_20-082A3B in strain 20-082A3 was almost identical (>99.9%) to that of strain 19-021-D1. Moreover, strains 20-082A3 and 19-021-D1 exhibited the same multilocus sequence type (ST 413) and serotype (O1:Un-typeable K-serogroup), suggesting that the mutant strain is closely related to and may have originated from the virulent strain 19-021-D1. Similar to previous reports on the natural mutant Vp_AHPND, strain 20-082A3 did not induce AHPND-related symptoms or cause mortality in the shrimp bioassay. The emergence of a mutant strain which is almost identical to the virulent Vp_AHPND highlights the need for surveillance of the pathogen prevalent in Korea. Further investigations to elucidate the potential relationship between ST 413 and recent Korean Vp_AHPND isolates are needed. Full article