Galleria mellonella infection model demonstrates high lethality of ST69 and ST127 uropathogenic E. coli.

Galleria mellonella larvae are an alternative in vivo model for investigating bacterial pathogenicity. Here, we examined the pathogenicity of 71 isolates from five leading uropathogenic E. coli (UPEC) lineages using G. mellonella larvae. Larvae were challenged with a range of inoculum doses to determine the 50% lethal dose (LD50) and for analysis of survival outcome using Kaplan-Meier plots. Virulence was correlated with carriage of a panel of 29 virulence factors (VF). Larvae inoculated with ST69 and ST127 isolates (10(4) colony-forming units/larvae) showed significantly higher mortality rates than those infected with ST73, ST95 and ST131 isolates, killing 50% of the larvae within 24 hours. Interestingly, ST131 isolates were the least virulent. We observed that ST127 isolates are significantly associated with a higher VF-score than isolates of all other STs tested (P≤0.0001), including ST69 (P<0.02), but one ST127 isolate (strain EC18) was avirulent. Comparative genomic analyses with virulent ST127 strains revealed an IS1 mediated deletion in the O-antigen cluster in strain EC18, which is likely to explain the lack of virulence in the larvae infection model. Virulence in the larvae was not correlated with serotype or phylogenetic group. This study illustrates that G. mellonella are an excellent tool for investigation of the virulence of UPEC strains. The findings also support our suggestion that the incidence of ST127 strains should be monitored, as these isolates have not yet been widely reported, but they clearly have a pathogenic potential greater than that of more widely recognised clones, including ST73, ST95 or ST131

Trends in ExPEC serogroups in the UK and their significance

We thank the British Society for Antimicrobial Chemotherapy for kindly providing E. coli bloodstream isolates from the BSAC Bacteraemia Resistance Surveillance Programme (2011), and all the staff at PHE’s Gastrointestinal Bacteria Reference Unit for their guidance and patience during the serogrouping process. This work was performed as part of a PhD study funded by PHE

Antibiotic-resistant ST38, ST131 and ST405 strains are the leading uropathogenic Escherichia coli clones in Riyadh, Saudi Arabia.

OBJECTIVES: We investigated the molecular epidemiology of uropathogenic Escherichia coli (UPEC) from a tertiary care hospital in Riyadh, Saudi Arabia, revealing, for the first time, the population structure of UPEC in the region. METHODS: A total of 202 UPEC isolates were recovered from hospital and community patients with urinary tract infection in December 2012 and January 2013. Strains were characterized by MLST, antibiotic susceptibility determination and virulence gene detection. RESULTS: The most common lineages were ST131 (17.3%), ST73 (11.4%), ST38 (7.4%), ST69 (7.4%), ST10 (6.4%), ST127 (5.9%), ST95 (5.4%), ST12 (3.5%), ST998 (3.5%) and ST405 (3%). ST131 and ST405 isolates were significantly associated with high levels of antibiotic resistance (60% of ST131 carried CTX-M-14 or CTX-M-15 and 66.7% of ST405 isolates carried CTX-M-15). ST131, CTX-M-15-positive isolates were predominantly of the fimH30/clade C group, resistant to fluoroquinolones; members of this sub-group were more likely to carry a high number of genes encoding selected virulence determinants. The relatively high proportion of ST38 was notable and four of these isolates harboured aggR. CONCLUSIONS: Our findings highlight the presence of MDR, CTX-M-positive ST38, ST131 and ST405 UPEC in Saudi Arabia. The high proportion of isolates with CTX-M is a particular concern. We suggest that ST38 UPEC warrant further study

Systematic review of multidrug-resistant Klebsiella pneumoniae in the Arabian Peninsula: molecular epidemiology and resistance patterns

BackgroundThe rapid emergence of multidrug-resistant Klebsiella pneumoniae (MDR K. pneumoniae) is a major public health and economic burden worldwide. Various resistance mechanisms complicate treatment, leading to increased morbidity and mortality. Despite numerous studies conducted in Gulf Health Council (GHC) countries, the molecular epidemiology of MDR K. pneumoniae remains not clearly defined. This systematic review aims to analyze the emergence of antimicrobial resistance genes in MDR K. pneumoniae across GHC countries.MethodsA systematic search was conducted using PubMed, ScienceDirect, and OpenMD for articles published up to March 15, 2023. The search strategy focused on the bacterial name, drug-resistance genotypes, and GHC countries. The review followed PRISMA guidelines, with two independent reviewers assessing the risk of bias using NIH Study Quality Assessment tools.ResultsThe primary search yielded 1,663 studies, of which 67 met the inclusion criteria. Saudi Arabia contributed the most studies, with 41 (61.1%), followed by Kuwait with 7 (10.4%), and the UAE with 6 (9%) studies. Oman and Qatar each contributed 4 studies (6%), and Bahrain contributed three studies (4.5%). The remaining 4 studies (4.4%) were from multiple GHC countries. The studies exhibited considerable heterogeneity in detection methods, target genes, and resistance mechanisms. Notably, only one environmental study was conducted in the UAE, and one community-based study in Kuwait, while the remaining studies focused on clinical samples. Various resistance mechanisms and patterns were observed between countries and across different years within the same country. The review highlighted the widespread prevalence of ESBL genes, particularly blaTEM and blaCTX-M-15, and the emergence of carbapenemase genes such as blaOXA-48 and blaNDM-1 and blaKPC-2. Additionally, colistin resistance through the mcr-1 gene and mgrB mutations was reported in Saudi Arabia and the UAE, posing a significant public health challenge.ConclusionData from GHC countries shows significant gaps, particularly in community and environmental and molecular epidemiology studies. Limited molecular and genome-based investigations hinder comprehensive AMR surveillance. Implementing standardized methodologies and fostering molecular and genome-based AMR surveillance programs at both national and regional levels within the GHC are essential for effectively combating the spread of MDR K. pneumoniae and improving public health outcomes in the region

S. Enteritidis and S. Typhimurium Harboring SPI-1 and SPI-2 Are the Predominant Serotypes Associated With Human Salmonellosis in Saudi Arabia

Non-typhoidal Salmonella (NTS) strains are Gram negative bacterial pathogens that are associated with foodborne illness worldwide. During the process of infection, Salmonella uses two molecular injectisomes known as Type 3 Secretion Systems (T3SS) to secrete virulence factors that are encoded by Salmonella Pathogenicity Island-1 (SPI-1) and SPI-2 into host cells. These secretion systems play a major role in virulence, as shown in various animal models, but little is known about their role in human infections. In Saudi Arabia, NTS strains frequently cause human infections but data regarding these pathogenic strains is fairly limited. The aim of this study was to characterize Salmonella human clinical isolates in Riyadh, Saudi Arabia, by determining their serotype, testing for the presence of SPI-1 and SPI-2 genes and to determine the antibiotic resistance profiles of these strains. Using the rapid Check and Trace Salmonella™ (CTS) system our results demonstrate that S. Enteritidis and S. Typhimurium were the predominant serovars, followed by S. Livingstone, S. Kentucky and S. Poona among a list of 36 serovars reported for the first time in the country. In addition, SPI-1 genes were detected in 99% of the isolates, while the sifA gene (SPI-2) was not detected in 13.5% of the isolates. These results suggest that both the SPI-1 and SPI-2 virulence determinants are important for human infection. Moreover, we report the presence of a Multi-Drug (MDR) carbapenem resistant S. Kentucky isolate harboring the blaOXA−48 gene not reported previously in Saudi Arabia

The dissemination of multidrug-resistant and hypervirulent <em>Klebsiella pneumoniae</em> clones across the Kingdom of Saudi Arabia

\ua9 2024 The Author(s). Published by Informa UK Limited, trading as Taylor &amp; Francis Group, on behalf of Shanghai Shangyixun Cultural Communication Co., Ltd.Klebsiella pneumoniae is a Gram-negative bacterium associated with a wide range of community- and hospital-acquired infections. The emergence of clonal hypervirulent strains resistant to last-resort antimicrobial agents has become a global concern. The Kingdom of Saudi Arabia (KSA), with its diverse population and high tourism traffic, serves as a platform where the spread of multidrug-resistant (MDR) strains are facilitated. However, the knowledge of epidemiology and population diversity of MDR K. pneumoniae in KSA is scarce. We conducted a comprehensive genomic survey on 352 MDR K. pneumoniae isolates systematically collected from bloodstream and urinary tract infections in 34 hospitals across 15 major cities in KSA during 2022 and 2023. Whole-genome sequencing on the isolates was performed, followed by genomic epidemiology and phylodynamic analysis. Our study revealed a dynamic population characterized by the rapid expansion of several dominant clones, including, ST2096, ST147, and ST231, which were estimated to have emerged within the past decade. These clones exhibited widespread dissemination across hospitals and were genetically linked to global strains, particularly from the Middle East and South Asia. All major clones harboured plasmid-borne ESBLs and carbapenemase genes, with plasmidome analysis identifying multiple IncH, IncA/C and IncL plasmids underlying the MDR-hypervirulent phenotype. These plasmids were shared between major clones and became acquired on the same time scales as the expansion of the dominant clones. Our results report ST2096 as an emerging MDR-hypervirulent clone, emphasizing the need for monitoring of the circulating clones and their plasmid content in the KSA and broader West Asia

Methicillin-resistant <em>Staphylococcus aureus</em> in Saudi Arabia: genomic evidence of recent clonal expansion and plasmid-driven resistance dissemination

Copyright \ua9 2025 Alhejaili, Zhou, Halawa, Huang, Fallatah, Hirayban, Iftikhar, AlAsmari, Milner, Banzhaf, Alzaidi, Rajeh, Al-Otaiby, Alabbad, Bukhari, Aljurayyan, Aljasham, Alzeyadi, Alajel, Alanazi, Alghoribi, Almutairi, Pain, Senok, Moradigaravand and Al Salem.Objectives: Staphylococcus aureus is a leading cause of hospital-acquired infections worldwide. Over recent decades, methicillin-resistant Staphylococcus aureus (MRSA), which is resistant to multiple antimicrobials, has emerged as a significant pathogenic strain in both hospital and community settings. The rapid emergence and dissemination of MRSA clones are driven by a dynamic and evolving population, spreading swiftly across regions on epidemiological time scales. Despite the vast geographical expanse and diverse demographics of the Kingdom of Saudi Arabia and the broader West Asia region, the population diversity of MRSA in hospitals in these areas remains underexplored. Methods: We conducted a large-scale genomic analysis of a systematic Staphylococcus aureus collection obtained from 34 hospitals across all provinces of KSA, from diverse body sites between 2022 and 2024. The dataset comprised 581 MRSA and 31 methicillin-susceptible Staphylococcus aureus (MSSA) isolates, all subjected to whole-genome sequencing. A combination of phylogenetic and population genomics approaches was utilized to analyze the genomic data. Hybrid sequencing approach was employed to retrieve the complete plasmid content. Results: The population displayed remarkable diversity, comprising 48 distinct sequence types (STs), with the majority harboring community-associated SCCmec loci (types IVa, V/VII, and VI). Virulence factors associated with community-acquired MRSA (CA-MRSA), including Panton-Valentine Leukocidin (PVL) genes, were identified in 12 distinct STs. Dominant clones, including ST8-t008 (USA300), ST88-t690, ST672-t3841, ST6-t304, and ST5-t311, were associated with infections at various body sites and were widely disseminated across the country. Linezolid and vancomycin resistance were mediated by cfr-carrying plasmids and mutations in the vraR gene (involved in cell-wall stress response) and the murF gene (involved in peptidoglycan biosynthesis) in five isolates, respectively. Phylodynamic analysis revealed rapid expansion of the dominant clones, with their emergence estimated to have occurred 10–20 years ago. Plasmidome analysis uncovered a diverse repertoire of blaZ-containing plasmids and the sharing of erm(C)-encoding plasmids among major clades. The acquisition of plasmids coincided with clonal expansion. Conclusions: Our results highlight the recent concurrent expansion and geographical dissemination of CA-MRSA clones across hospitals. These findings also underscore the interplay between clonal spread and horizontal gene transfer in shaping the resistance landscape of MRSA

Establishing a marine monitoring programme to assess antibiotic resistance: a case study from the Gulf Cooperation Council (GCC) region

The World Health Organization considers antimicrobial resistance as one of the most pressing global issues which poses a fundamental threat to human health, development, and security. Due to demographic and environmental factors, the marine environment of the Gulf Cooperation Council (GCC) region may be particularly susceptible to the threat of antimicrobial resistance. However, there is currently little information on the presence of AMR in the GCC marine environment to inform the design of appropriate targeted surveillance activities. The objective of this study was to develop, implement and conduct a rapid regional baseline monitoring survey of the presence of AMR in the GCC marine environment, through the analysis of seawater collected from high-risk areas across four GCC states: (Bahrain, Oman, Kuwait, and the United Arab Emirates). 560 Escherichia coli strains were analysed as part of this monitoring programme between December 2018 and May 2019. Multi-drug resistance (resistance to three or more structural classes of antimicrobials) was observed in 32.5% of tested isolates. High levels of reduced susceptibility to ampicillin (29.6%), nalidixic acid (27.9%), tetracycline (27.5%), sulfamethoxazole (22.5%) and trimethoprim (22.5%) were observed. Reduced susceptibility to the high priority critically important antimicrobials: azithromycin (9.3%), ceftazidime (12.7%), cefotaxime (12.7%), ciprofloxacin (44.6%), gentamicin (2.7%) and tigecycline (0.5%), was also noted. A subset of 173 isolates was whole genome sequenced, and high carriage rates of qnrS1 (60/173) and bla CTX-M-15 (45/173) were observed, correlating with reduced susceptibility to the fluoroquinolones and third generation cephalosporins, respectively. This study is important because of the resistance patterns observed, the demonstrated utility in applying genomic-based approaches to routine microbiological monitoring, and the overall establishment of a transnational AMR surveillance framework focussed on coastal and marine environments

Methicillin-resistant Staphylococcus aureus in Saudi Arabia: genomic evidence of recent clonal expansion and plasmid-driven resistance dissemination

Objectives: Staphylococcus aureus is a leading cause of hospital-acquired infections worldwide. Over recent decades, methicillin-resistant Staphylococcus aureus (MRSA), which is resistant to multiple antimicrobials, has emerged as a significant pathogenic strain in both hospital and community settings. The rapid emergence and dissemination of MRSA clones are driven by a dynamic and evolving population, spreading swiftly across regions on epidemiological time scales. Despite the vast geographical expanse and diverse demographics of the Kingdom of Saudi Arabia and the broader West Asia region, the population diversity of MRSA in hospitals in these areas remains underexplored. Methods: We conducted a large-scale genomic analysis of a systematic Staphylococcus aureus collection obtained from 34 hospitals across all provinces of KSA, from diverse body sites between 2022 and 2024. The dataset comprised 581 MRSA and 31 methicillin-susceptible Staphylococcus aureus (MSSA) isolates, all subjected to whole-genome sequencing. A combination of phylogenetic and population genomics approaches was utilized to analyze the genomic data. Hybrid sequencing approach was employed to retrieve the complete plasmid content. Results: The population displayed remarkable diversity, comprising 48 distinct sequence types (STs), with the majority harboring community-associated SCCmec loci (types IVa, V/VII, and VI). Virulence factors associated with community-acquired MRSA (CA-MRSA), including Panton-Valentine Leukocidin (PVL) genes, were identified in 12 distinct STs. Dominant clones, including ST8-t008 (USA300), ST88-t690, ST672-t3841, ST6-t304, and ST5-t311, were associated with infections at various body sites and were widely disseminated across the country. Linezolid and vancomycin resistance were mediated by cfr-carrying plasmids and mutations in the vraR gene (involved in cell-wall stress response) and the murF gene (involved in peptidoglycan biosynthesis) in five isolates, respectively. Phylodynamic analysis revealed rapid expansion of the dominant clones, with their emergence estimated to have occurred 10–20 years ago. Plasmidome analysis uncovered a diverse repertoire of blaZ-containing plasmids and the sharing of erm(C)-encoding plasmids among major clades. The acquisition of plasmids coincided with clonal expansion. Conclusions: Our results highlight the recent concurrent expansion and geographical dissemination of CA-MRSA clones across hospitals. These findings also underscore the interplay between clonal spread and horizontal gene transfer in shaping the resistance landscape of MRSA