Multi-state study of Enterobacteriaceae harboring extended-spectrum beta-lactamase and carbapenemase genes in U.S. drinking water

Extended-spectrum beta-lactamase (ESBL)- and non-ESBL producing Escherichia coli surveillance in surface water sources in Edo State, Nigeria: a public health concern

This research explores the antimicrobial resistance (AMR) profiles and prevalence of extended-spectrum beta-lactamase (ESBL) and non-ESBL-producing Escherichia coli in Ojerame Dam and Ovokoto Spring, Edo State, Nigeria. Over 12 months, water was systematically sampled to accommodate seasonal variations and analyzed by employing an ESBL-selective medium for bacterial species. Additionally, bacterial isolates underwent identification and characterization using polymerase chain reaction (PCR) and disk diffusion methods to evaluate their susceptibility to antimicrobials. Results indicated significant prevalence of ESBL-producing E. coli, which exhibited complete resistance to common antimicrobials like ceftriaxone, ceftazidime, cefotaxime, and ampicillin while demonstrating 100% sensitivity to ertapenem, imipenem, meropenem, and nitrofurantoin. Non-ESBL-producing E. coli were resistant to ampicillin but sensitive to other antimicrobials mentioned earlier. Furthermore, both ESBL and non-ESBL-producing E. coli displayed multidrug resistance to varying degrees. Specific ESBL genes, including blaTEM, blaCTX-M-1, and blaCTX-M-15, were identified, alongside resistance genes like tetA, tetM, sul1, sul2, sul3, qnrA, qnrB, and qnrS in E. coli. This study pioneers the documentation of ESBL-producing E. coli in surface water in the region. This signals impending health risks associated with water being a reservoir of resistant genes while emphasizing the urgency for further research and public awareness concerning the quality of surface water.

Misidentification and misreporting of antibiotic resistance in Kluyvera bacteremia by blood culture molecular identification panels

The use of molecular identification panels has advanced the diagnosis for blood stream infections with fast turnaround time and high accuracy. Yet, this technology cannot completely replace conventional blood culture and standardized antibiotic susceptibility testing (AST) given its limitations and occasional false results. Here we present two cases of bacteremia caused by Kluyvera. Its identification and antibiotic resistance were at least partially mispresented by blood culture molecular identification panels on ePlex, Verigene, and Biofire. The detection of CTX-M resistance marker did not align with the susceptibility to the third generation cephalosporins among a wide range of antibiotics for this organism. Conventional extended-spectrum beta-lactamase (ESBL) testing was used to confirm the absence of ESBL. Caution should be taken when managing cases with CTX-M or ESBL detection in blood culture caused by uncommon pathogens. Conventional culture with microbial identification and standardized AST should continue to be the gold standard for routine patient care.

IMPORTANCE

This is the first report that highlights the limitations of blood culture molecular identification panels on identifying Kluyvera and its associated antibiotic resistance patterns. Both the false identification and overreporting of antibiotic resistance could mislead the treatment for bacteremia caused by this pathogen. Patient isolation could have been avoided due to the lack of extended-spectrum beta-lactamase (ESBL) activity of the organism. This report emphasizes the importance of confirming rapid identification and antibiotic resistance by molecular technologies with standardized methods. It also provides insight into the development of new diagnostic panels.

Phylogenetic group distribution and antibiotic resistance of Escherichia coli isolates in aquatic environments of a highly populated area

Background

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae including Escherichia coli (E. coli), are recognized as a global public health threat due to their multidrug-resistant (MDR) phenotypes and their rapid dissemination in aquatic environments. Nevertheless, studies investigating the prevalence and antimicrobial resistance (AMR) profile of ESBL-producing E. coli in Lebanese surface water are limited.

Objective

This study aimed to assess the physicochemical properties and microbial contamination load and to determine the distribution of AMR patterns of ESBL-producing E. coli in surface water samples from different sites in the North Governorate of Lebanon.

Methods

Water samples were collected from 25 major sites in North Lebanon. These samples were analyzed for the presence of total coliforms, E. coli, and fecal enterococci. Phenotypic and genetic characterizations were then performed for E. coli isolates to determine their resistance patterns and phylogenetic groups.

Results

Fifty-six samples out of 100 samples were positive for ESBL-producing E. coli, mostly harboring blaCTX-M (40/56, 71%) including blaCTX-M-15 (33/40, 82%), blaTEM gene (36/56, 64%), blaSHV (20/56, 36%), and blaOXA (16/56, 29%) including blaOXA-48 gene (11/16, 69%). Most ESBL-producing E. coli isolates belonged to the extra-intestinal pathogenic phylogroup B2 (40/56, 71.4%) while 10/56 (17.9%) belonged to the commensal phylogroup A.

Conclusion

Our results highlight the need to implement effective water monitoring strategies to control transmission of ESBL-producing E. coli in surface water and thus reduce the burden on human and animal health.

Network meta-analysis of antibiotic resistance patterns in gram-negative bacterial infections: a comparative study of carbapenems, fluoroquinolones, and aminoglycosides

Introduction

Antimicrobial resistance poses a grave global threat, particularly with the emergence of multidrug-resistant gram-negative bacterial infections, which severely limit treatment options. The increasing global threat of antimicrobial resistance demands rigorous investigation, particularly concerning multidrug-resistant gram-negative bacterial infections that present limited therapeutic options. This study employed a network meta-analysis, a powerful tool for comparative effectiveness assessment of diverse antibiotics. The primary aim of this study was to comprehensively evaluate and compare resistance patterns among widely used antibiotic classes, namely carbapenems, fluoroquinolones, and aminoglycosides, for combating gram-negative pathogens.

Methods

We searched PubMed, Web of Sciences, Scopus, Scholarly, Medline, Embase, and Cochrane databases up to August 27, 2023. Studies showing antibiotic resistance in clinical isolates of Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii exposed to carbapenems, fluoroquinolones, and aminoglycosides were included. This study determined treatment-specific resistance percentages and ranked these treatments based on resistance using a random-effects network meta-analysis technique. To investigate the impact of the study and pathogen features, subgroup and meta-regression analyses were performed. Risk ratios and 95% confidence intervals (CIs) were calculated using a network meta-analysis (NMA) incorporating both direct and indirect evidence. Clinical improvement, cure, microbiological eradication, and death from any cause were the primary outcomes. Nephrotoxicity was a secondary result.

Results

The analysis included 202 publications and 365,782 gram-negative isolates. The NMA included data from 20 studies and 4,835 patients. Carbapenems had the lowest resistance rates throughout the pathogen spectrum, with resistance percentages of 17.1, 22.4, and 33.5% for Enterobacteriaceae, P. aeruginosa, and A. baumannii, respectively. For the same infections, aminoglycosides showed resistance rates of 28.2, 39.1, and 50.2%, respectively. Fluoroquinolones had the highest resistance rates at 43.1, 57.3, and 65.7%, respectively. Unexpectedly, resistance to all three antibiotic classes has increased over time, with multidrug resistance being the most prevalent.

Conclusion

This extensive network meta-analysis provides an overview of the patterns of resistance throughout the world and how they are changing. The most effective choice is still carbapenems, but the increasing resistance highlights the critical need for multimodal therapies to protect antibiotic effectiveness against these powerful gram-negative infections.

Distribution of Antibiotic Resistance in a Mixed-Use Watershed and the Impact of Wastewater Treatment Plants on Antibiotic Resistance in Surface Water

The aquatic environment has been recognized as a source of antibiotic resistance (AR) that factors into the One Health approach to combat AR. To provide much needed data on AR in the environment, a comprehensive survey of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antibiotic residues was conducted in a mixed-use watershed and wastewater treatment plants (WWTPs) within the watershed to evaluate these contaminants in surface water. A culture-based approach was used to determine prevalence and diversity of ARB in surface water. Low levels of AR Salmonella (9.6%) and Escherichia coli (6.5%) were detected, while all Enterococcus were resistant to at least one tested antibiotic. Fewer than 20% of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (17.3%) and carbapenem-resistant Enterobacteriaceae (CRE) (7.7%) were recovered. Six ARGs were detected using qPCR, primarily the erythromycin-resistance gene, ermB. Of the 26 antibiotics measured, almost all water samples (98.7%) had detectable levels of antibiotics. Analysis of wastewater samples from three WWTPs showed that WWTPs did not completely remove AR contaminants. ARGs and antibiotics were detected in all the WWTP effluent discharges, indicating that WWTPs are the source of AR contaminants in receiving water. However, no significant difference in ARGs and antibiotics between the upstream and downstream water suggests that there are other sources of AR contamination. The widespread occurrence and abundance of medically important antibiotics, bacteria resistant to antibiotics used for human and veterinary purposes, and the genes associated with resistance to these antibiotics, may potentially pose risks to the local populations exposed to these water sources.

Detection and Characterization of Carbapenemase-Producing Escherichia coli and Klebsiella pneumoniae from Hospital Effluents of Ouagadougou, Burkina Faso

Hospital wastewater is a recognized reservoir for resistant Gram-negative bacteria. This study aimed to screen for carbapenemase-producing Escherichia coli and Klebsiella pneumoniae and their resistance determinants in two hospital effluents of Ouagadougou. Carbapenem-resistant E. coli and K. pneumoniae were selectively isolated from wastewater collected from two public hospitals in Ouagadougou, Burkina Faso. Bacterial species were identified via MALDI-TOF mass spectrometry. Carbapenemase production was studied phenotypically using antibiotic susceptibility testing via the disk diffusion method. The presence of carbapenemases was further characterized by PCR. A total of 14 E. coli (13.59%) and 19 K. pneumoniae (17.92%) carbapenemase-producing isolates were identified with different distributions. They were, respectively, blaNDM (71.43%), blaVIM (42.86%), blaIMP (28.57%), blaKPC (14.29%), blaOXA-48 (14.29%); and blaKPC (68.42%), blaNDM (68.42%), blaIMP (10.53%), blaVIM (10.53%), and blaOXA-48 (5.26%). In addition, eight (57.14%) E. coli and eleven (57.89%) K. pneumoniae isolates exhibited more than one carbapenemase, KPC and NDM being the most prevalent combination. Our results highlight the presence of clinically relevant carbapenemase-producing isolates in hospital effluents, suggesting their presence also in hospitals. Their spread into the environment via hospital effluents calls for intensive antimicrobial resistance (AMR) surveillance.

Rapid Isolation of Low-Level Carbapenem-Resistant E. coli from Water and Foods Using Glycan-Coated Magnetic Nanoparticles

Carbapenem-resistant Enterobacterales (CRE) are one of the major global issues needing attention. Among them, carbapenemase-producing (CP) E. coli strains are commonly found in clinical and biological samples. Rapid and cost-effective detection of such strains is critical in minimizing their deleterious impact. While promising progress is being made in rapid detection platforms, separation and enrichment of bacteria are required to ensure the detection of low bacterial counts. The current separation methods, such as centrifugation, filtration, electrophoresis, and immunomagnetic separation, are often tedious, expensive, or ineffective for clinical and biological samples. Further, the extraction and concentration of antimicrobial-resistant bacteria (ARB) are not well documented. Thus, this study assessed the applicability of cost-effective glycan-coated magnetic nanoparticles (gMNPs) for simple and rapid extraction of CP E. coli. The study included two resistant (R)strains: Klebsiella pneumoniae carbapenemase (KPC)-producing E. coli (R: KPC) and New Delhi metallo-β-lactamase (NDM)-producing E. coli (R: NDM). A susceptible E. coli (S) strain was used as a control, a reference bacterium. The gMNPs successfully extracted and concentrated E. coli (R) and E. coli (S) at low concentrations from large volumes of buffer solution, water, and food samples. The gMNPs concentrated up to two and five times their initial concentration for E. coli (R) and E. coli (S) in the buffer solution, respectively. In water and food samples, the concentration of E. coli (S) and E. coli (R) were similar and ranged 1-3 times their initial inoculation. A variation in the concentration from different food samples was seen, displaying the impact of food microstructure and natural microflora. The cost-effective and rapid bacterial cell capture by gMNPs was achieved in 15 min, and its successful binding to the bacterial cells in the buffer solution and food matrices was also confirmed using Transmission Electron Microscopy (TEM). These results show promising applications of gMNPs to extract pathogens and ARB from biological samples.

A Review of Carbapenem Resistance in Enterobacterales and Its Detection Techniques

Infectious disease outbreaks have caused thousands of deaths and hospitalizations, along with severe negative global economic impacts. Among these, infections caused by antimicrobial-resistant microorganisms are a major growing concern. The misuse and overuse of antimicrobials have resulted in the emergence of antimicrobial resistance (AMR) worldwide. Carbapenem-resistant Enterobacterales (CRE) are among the bacteria that need urgent attention globally. The emergence and spread of carbapenem-resistant bacteria are mainly due to the rapid dissemination of genes that encode carbapenemases through horizontal gene transfer (HGT). The rapid dissemination enables the development of host colonization and infection cases in humans who do not use the antibiotic (carbapenem) or those who are hospitalized but interacting with environments and hosts colonized with carbapenemase-producing (CP) bacteria. There are continuing efforts to characterize and differentiate carbapenem-resistant bacteria from susceptible bacteria to allow for the appropriate diagnosis, treatment, prevention, and control of infections. This review presents an overview of the factors that cause the emergence of AMR, particularly CRE, where they have been reported, and then, it outlines carbapenemases and how they are disseminated through humans, the environment, and food systems. Then, current and emerging techniques for the detection and surveillance of AMR, primarily CRE, and gaps in detection technologies are presented. This review can assist in developing prevention and control measures to minimize the spread of carbapenem resistance in the human ecosystem, including hospitals, food supply chains, and water treatment facilities. Furthermore, the development of rapid and affordable detection techniques is helpful in controlling the negative impact of infections caused by AMR/CRE. Since delays in diagnostics and appropriate antibiotic treatment for such infections lead to increased mortality rates and hospital costs, it is, therefore, imperative that rapid tests be a priority.

The role of plasmids in carbapenem resistant E. coli in Alameda County, California

BACKGROUND

Antimicrobial resistant infections continue to be a leading global public health crisis. Mobile genetic elements, such as plasmids, have been shown to play a major role in the dissemination of antimicrobial resistance (AMR) genes. Despite its ongoing threat to human health, surveillance of AMR in the United States is often limited to phenotypic resistance. Genomic analyses are important to better understand the underlying resistance mechanisms, assess risk, and implement appropriate prevention strategies. This study aimed to investigate the extent of plasmid mediated antimicrobial resistance that can be inferred from short read sequences of carbapenem resistant E. coli (CR-Ec) in Alameda County, California. E. coli isolates from healthcare locations in Alameda County were sequenced using an Illumina MiSeq and assembled with Unicycler. Genomes were categorized according to predefined multilocus sequence typing (MLST) and core genome multilocus sequence typing (cgMLST) schemes. Resistance genes were identified and corresponding contigs were predicted to be plasmid-borne or chromosome-borne using two bioinformatic tools (MOB-suite and mlplasmids).

RESULTS

Among 82 of CR-Ec identified between 2017 and 2019, twenty-five sequence types (STs) were detected. ST131 was the most prominent (n = 17) followed closely by ST405 (n = 12). bla_CTX-M were the most common ESBL genes and just over half (18/30) of these genes were predicted to be plasmid-borne by both MOB-suite and mlplasmids. Three genetically related groups of E. coli isolates were identified with cgMLST. One of the groups contained an isolate with a chromosome-borne bla_CTX-M-15 gene and an isolate with a plasmid-borne bla_CTX-M-15 gene.

CONCLUSIONS

This study provides insights into the dominant clonal groups driving carbapenem resistant E. coli infections in Alameda County, CA, USA clinical sites and highlights the relevance of whole-genome sequencing in routine local genomic surveillance. The finding of multi-drug resistant plasmids harboring high-risk resistance genes is of concern as it indicates a risk of dissemination to previously susceptible clonal groups, potentially complicating clinical and public health intervention.

Antimicrobial Resistance Is Prevalent in E. coli and Other Enterobacterales Isolated from Public and Private Drinking Water Supplies in the Republic of Ireland

High levels of bacterial antimicrobial resistance (AMR) have been reported in many environmental studies conducted in Ireland and elsewhere. The inappropriate use of antibiotics in both human and animal healthcare as well as concentrations of residual antibiotics being released into the environment from wastewaters are thought to be contributing factors. Few reports of AMR in drinking water-associated microbes are available for Ireland or internationally. We analysed 201 enterobacterales from group water schemes and public and private water supplies, only the latter having been surveyed in Ireland previously. The organisms were identified using conventional or molecular techniques. Antimicrobial susceptibility testing for a range of antibiotics was performed using the ARIS 2X interpreted in accordance with EUCAST guidelines. A total of 53 Escherichia coli isolates, 37 Serratia species, 32 Enterobacter species and enterobacterales from seven other genera were identified. A total of 55% of isolates were amoxicillin resistant, and 22% were amoxicillin-clavulanic acid resistant. A lower level of resistance (<10%) was observed to aztreonam, chloramphenicol, ciprofloxacin, gentamicin, ceftriaxone and trimethoprim-sulfamethoxazole. No resistance to amikacin, piperacillin/tazobactam, ertapenem or meropenem was detected. The level of AMR detected in this study was low but not insignificant and justifies ongoing surveillance of drinking water as a potential source of antimicrobial resistance.

Carbon/nitrogen ratios determine biofilm formation and characteristics in model microbial cultures

The influence of growth medium water chemistry, specifically carbon/nitrogen (C/N) molar ratios, on the characteristics and development of biofilms of the model microorganism Pseudomonas aeruginosa was investigated. C/N = 9 had a unique effect on biofilm composition as well as quorum sensing (QS) pathways, with higher concentrations of carbohydrates and proteins in the biofilm and a significant upregulation of the QS gene lasI in planktonic cells. The effect of C/N ratio on total attached biomass was negligible. Principal component analysis revealed a different behavior of most outputs such as carbohydrates and QS chemicals at C/N = 9, and pointed to correlations between parameters of biofilm formation and steady state distribution of cells and extracellular components. C/N ratio was also shown to influence organic compound utilization by both planktonic and sessile organisms, with a maximum chemical oxygen demand (COD) removal of 83% achieved by biofilms at C/N = 21. Planktonic cells achieved higher COD removal rates, but greater overall rates after six days occurred in biofilms. The development of a dual-species biofilm of P. aeruginosa and Nitrobacter winogradskyi was also influenced by C/N, with increase in the relative abundance of the slower-growing N. winogradskyi above C/N = 9. These results indicate that altering operational parameters related to C/N would be relevant for mitigating or promoting biofilm formation and function depending on the desired industrial application or treatment configuration.

Dialysis Water Supply Faucet as Reservoir for Carbapenemase-Producing Pseudomonas aeruginosa

During June 2017-November 2019, a total 36 patients with carbapenem-resistant Pseudomonas aeruginosa harboring Verona-integron-encoded metallo-β-lactamase were identified in a city in western Texas, USA. A faucet contaminated with the organism, identified through environmental sampling, in a specialty care room was the likely source for infection in a subset of patients.

Biofilm-responsive encapsulated-phage coating for autonomous biofouling mitigation in water storage systems

Biofilms in water storage systems may harbor pathogens that threaten public health. Chemical disinfectants are marginally effective in eradicating biofilms due to limited penetration, and often generate harmful disinfection byproducts. To enhance biofouling mitigation in household water storage tanks, we encapsulated bacteriophages (phages) in chitosan crosslinked with tri-polyphosphate and 3-glycidoxypropyltrimethoxysilane. Phages served as self-propagating green biocides that exclusively infect bacteria. This pH-responsive encapsulation (244 ± 11 nm) enabled autonomous release of phages in response to acidic pH associated with biofilms (corroborated by confocal microscopy with pH-indicator dye SNARF-4F), but otherwise remained stable in pH-neutral tap water for one month. Encapsulated phages instantly bind to plasma-treated plastic and fiberglass surfaces, providing a facile coating method that protects surfaces highly vulnerable to biofouling. Biofilm formation assays were conducted in tap water amended with 200 mg/L glucose to accelerate growth and attachment of Pseudomonas aeruginosa, an opportunistic pathogen commonly associated with biofilms in drinking water distribution and storage systems. Biofilms formation on plastic surfaces coated with encapsulated phages decreased to only 6.7 ± 0.2% (on a biomass basis) relative to the uncoated controls. Likewise, biofilm surface area coverage (4.8 ± 0.2 log CFU/mm²) and live/dead fluorescence ratio (1.80) were also lower than the controls (6.6 ± 0.2 log CFU/mm² and live/dead ratio of 11.05). Overall, this study offers proof-of-concept of a chemical-free, easily implementable approach to control problematic biofilm-dwelling bacteria and highlights benefits of this bottom-up biofouling control approach that obviates the challenge of poor biofilm penetration by biocides.

Carbapenemase producing Enterobacteriaceae: Environmental reservoirs as primary targets for control and prevention strategies

Carbapenemase-producing Enterobacteriaceae (CPE) have become one of the greatest public health challenges globally. In the past decade, antimicrobial resistance (AMR) was viewed as a clinical problem in many parts of the world; hence, the role and magnitude of the contribution of the environment were not well appreciated. This review article was done with online published articles extracted from different databases using search terms related to the work. Evidence has shown that there exists the presence of carbapenemase genes in the environment, consequently fuelling the dissemination with alarming consequences. CPE when acquired causes life-threatening infections in humans. The health and economic impact of these infections are numerous, including treatment failure due to limited therapeutic options which hamper the containment of infectious diseases, further contaminating the environment and worsening the public health challenge. It is a well-known fact that the rate of emergence of resistant genes has outpaced the production of new antimicrobial agents, so it is pertinent to institute effective environmental measures to combat the spread of AMR organisms before it will completely gain a foothold and take us back to 'the pre-antibiotic era'. Environmental sources and reservoirs of resistant genes should therefore be amongst the primary targets for the control and prevention of the spread of resistant genes in the environment. This calls for the effective implementation of the 'one health' strategy with stakeholders committed to the design and enforcement of environmental mitigation policies and guidelines.

Molecular Detection of blaSHV-la Gene in Klebsiella pneumonia Isolated from Urinary Tract Infections, Najaf, Iraq

Klebsiella pneumoniae is a gram-negative bacterium that causes serious illnesses, including pneumonia, liver abscess, meningitis, bloodstream infections, and urinary tract infections (UTIs). This study aimed to isolate and diagnose K. pneumoniae from clinical specimens of urine from patients with UTIs and perform molecular detection of the bla_SHV-la gene in K. pneumonia in the Najaf Province, Iraq. The study included 100 clinical specimens from October 2021 to March 2022. As an initial diagnosis, K. pneumoniae isolates were diagnosed based on culture and biochemical features. Apart from the usage of polymerase chain reaction (PCR) technology to identify the bla_SHV-la gene, the final diagnostic was achieved by the automated Vitek-2 compact system. The biochemical findings revealed that 40 out of every 100 isolates tested positive for K. pneumoniae. These results were validated by Vitek, which revealed that 40/100 of the samples tested positive for K. pneumoniae, and by PCR utilizing the bla_SHV-la gene, which showed that 13/40 of the samples tested positive for K. pneumoniae isolated from the urine of patients with UTIs. In conclusion, the results indicated that the use of the Vitek-2 technique was required to confirm the accurate identification of the pathogen. Klebsiella pneumoniae clinical isolates showed multidrug resistance to antibiotics commonly used to treat UTIs. The blaSHV gene encoded for Extended-spectrum beta-lactam antibiotic was found almost in K. pneumoniae isolates.

Raw Meat Contaminated with Cephalosporin-Resistant Enterobacterales as a Potential Source of Human Home Exposure to Multidrug-Resistant Bacteria

The prevalence of cephalosporine-resistant (3GC-R) strains among United States community-related research samples ranged from 5.6 to 10.8%, while, in the European countries, it was 1.2% to 10.1%. Several studies suggest that meat of animal origin could be one of the reservoirs of 3GC-R bacteria. Here, 86 raw meat samples (turkey, pork, chicken and beef) were collected randomly and verified for the presence of 3GC-R bacteria. The 3GC-R bacteria were isolated, identified and characterized phenotypically (antibiotic resistance, motility and biofilm) and genotypically (repetitive-sequence-based rep-PCR) to elucidate any correlations with principal component analysis (PCA). From 28 3GC-R positive samples, 41 strains were isolated, from which the majority belonged to Serratia fonticola (39%), followed by Escherichia coli (19.5%), Enterobacter cloacae (17.1%) and Klebsiella pneumoniae (14.6%). The isolates of E. coli and S. fonticola presented diverse profiles in rep-PCR. Generally, 3GC-R strains were more resistant to antibiotics used in veterinary medicine than in human medicine. PCA derived from antibiotic resistance, motility and biofilm formation of S. fonticola and E. coli strains showed that resistance to beta-lactams was separated from the resistance to other antibiotic classes. Moreover, for the S. fonticola, E. coli and En. cloacae, the type of meat can create a specific tendency towards antibiotic resistance and phenotypic characteristics for S. fonticola, while these relationships were not found for other tested species.

Naturalized Escherichia coli in Wastewater and the Co-evolution of Bacterial Resistance to Water Treatment and Antibiotics

Antibiotic resistance represents one of the most pressing concerns facing public health today. While the current antibiotic resistance crisis has been driven primarily by the anthropogenic overuse of antibiotics in human and animal health, recent efforts have revealed several important environmental dimensions underlying this public health issue. Antibiotic resistant (AR) microbes, AR genes, and antibiotics have all been found widespread in natural environments, reflecting the ancient origins of this phenomenon. In addition, modern societal advancements in sanitation engineering (i.e., sewage treatment) have also contributed to the dissemination of resistance, and concerningly, may also be promoting the evolution of resistance to water treatment. This is reflected in the recent characterization of naturalized wastewater strains of Escherichia coli-strains that appear to be adapted to live in wastewater (and meat packing plants). These strains carry a plethora of stress-resistance genes against common treatment processes, such as chlorination, heat, UV light, and advanced oxidation, mechanisms which potentially facilitate their survival during sewage treatment. These strains also carry an abundance of common antibiotic resistance genes, and evidence suggests that resistance to some antibiotics is linked to resistance to treatment (e.g., tetracycline resistance and chlorine resistance). As such, these naturalized E. coli populations may be co-evolving resistance against both antibiotics and water treatment. Recently, extraintestinal pathogenic strains of E. coli (ExPEC) have also been shown to exhibit phenotypic resistance to water treatment, seemingly associated with the presence of various shared genetic elements with naturalized wastewater E. coli. Consequently, some pathogenic microbes may also be evolving resistance to the two most important public health interventions for controlling infectious disease in modern society-antibiotic therapy and water treatment.

Clonal and plasmid-mediated dissemination of environmental carbapenem-resistant Enterobacteriaceae in large animal breeding areas in northern China

The emergence and dissemination of carbapenem-resistant Enterobacteriaceae (CRE) constitute a major global health problem. The environment plays an important role in the dissemination of CRE, but large-scale studies on CRE in groundwater environments in animal breeding areas are scarce. The aim of this study was to investigate CRE occurrence and environmental transmission of carbapenem resistance genes in large animal breeding areas in northern China. In total, 280 well water and 102 animal feces samples in large animal breeding areas in six counties from the two provinces Inner Mongolia and Shandong in China, were screened for CRE. A total of 39 CRE were isolated and characterized with next-generation sequencing. 5.3% of well water samples were contaminated with CRE. The well water in chicken farms had the highest number of detections of CRE (15.9%). More than half of the isolates carried closely related, conjugative IncX3 plasmids with bla_NDM-genes from multiple geographic areas, indicating that this kind of plasmid plays an important role in dissemination of carbapenem resistance determinants. The clonal expansion of various CRE isolates in well water and animal feces were demonstrated; clonally related CRE were isolated from different wells within the same county, from different counties in the same province, and even from different provinces. In addition to harboring various ARGs, two closely related K. pneumoniae belonging to ST11 isolated from well water carried genetic hypervirulence determinants on a virulence plasmid, highlighting the potential health risk posed by further dissemination of this strain. These findings suggest that groundwater may be an underappreciated reservoir and source of dissemination of CRE, from which resistance genes may disseminate among different bacterial strains and over large geographic distances. Further research and multi-sectorial monitoring, with a "One health" perspective, is urgently needed to investigate the need for interventions aimed at preventing CRE dissemination.

Carbapenem Resistance among Marine Bacteria-An Emerging Threat to the Global Health Sector

The emergence of antibiotic resistance among pathogenic microorganisms is a major issue for global public health, as it results in acute or chronic infections, debilitating diseases, and mortality. Of particular concern is the rapid and common spread of carbapenem resistance in healthcare settings. Carbapenems are a class of critical antibiotics reserved for treatment against multidrug-resistant microorganisms, and resistance to this antibiotic may result in limited treatment against infections. In addition to in clinical facilities, carbapenem resistance has also been identified in aquatic niches, including marine environments. Various carbapenem-resistant genes (CRGs) have been detected in different marine settings, with the majority of the genes incorporated in mobile genetic elements, i.e., transposons or plasmids, which may contribute to efficient genetic transfer. This review highlights the potential of the marine environment as a reservoir for carbapenem resistance and provides a general overview of CRG transmission among marine microbes.

Isolation of Ciprofloxacin and Ceftazidime-Resistant Enterobacterales From Vegetables and River Water Is Strongly Associated With the Season and the Sample Type

The dissemination of antibiotic-resistant bacteria (ARB) from water used for crop irrigation to vegetables is poorly studied. During a year, five farmer markets in a city in Central Chile were visited, and 478 vegetable samples (parsleys, corianders, celeries, lettuces, chards, and beets) were collected. Simultaneously, 32 water samples were collected from two rivers which are used to irrigate the vegetables produced in the area. Resistant Enterobacterales were isolated and identified. Colistin resistance gene mcr-1 and extended spectrum β-lactamases (ESBL) were molecularly detected. The association of environmental factors was evaluated, with the outcomes being the presence of Enterobacterales resistant to four antibiotic families and the presence of multidrug resistance (MDR) phenotypes. Parsley, coriander, and celery showed the highest prevalence of resistant Enterobacterales (41.9% for ciprofloxacin and 18.5% for ceftazidime). A total of 155 isolates were obtained, including Escherichia coli (n=109), Citrobacter sp. (n=20), Enterobacter cloacae complex (n=8), Klebsiella pneumoniae (n=8), and Klebsiella aerogenes (n=1). Resistance to ampicillin (63.2%) and ciprofloxacin (74.2%) was most frequently found; 34.5% of the isolates showed resistance to third-generation cephalosporins, and the MDR phenotype represented 51.6% of the isolates. In two E. coli isolates (1.29%), the gene mcr-1 was found and ESBL genes were found in 23/62 isolates (37%), with bla_CTX-M being the most frequently found in 20 isolates (32%). Resistant Enterobacterales isolated during the rainy season were less likely to be MDR as compared to the dry season. Understanding environmental associations represent the first step toward an improved understanding of the public health impact of ARB in vegetables and water.

Evaluation of private well contaminants in an underserved North Carolina community

On-site sewage treatment systems can be an important source of antibiotic resistant bacteria and organic micropollutants into adjacent groundwater. Due to the frequent proximity of private wells to septic systems, this contamination is a concern to communities that do not have access to public municipal services. In both rural and urban environments, low-income communities, indigenous communities and those of color are disproportionately affected by well contamination. The objective of this study was to assess well water quality in an underserved North Carolina community by performing a comprehensive evaluation of microbial and organic micropollutant occurrence and determining possible sources of contamination. Well water, septic tanks, and adjacent municipal water were sampled. Culture- and molecular biology-based microbial analysis and non-targeted, high resolution mass spectrometry chemical analysis were conducted to assess water quality in comparison to nearby municipal water. Three of thirteen homes had between 1 and 6.3 CFUs/100 mL of E. coli and two homes had fecal bacteria resistant to antibiotics in their well water. The water of four homes showed concentrations of the artificial sweetener sucralose, a wastewater tracer, higher than the municipal water (range ~ 60-1500 ng L^-1). The human-specific HF183 fecal marker was detected in 79% of the wells tested. The presence of pharmaceuticals and personal care products in four home wells, along with the presence of pesticides and insecticides in two homes, suggest possible contamination from septic tanks and lawn care runoff. The implications of this work highlight the necessity of wider scale contaminant evaluation of well water.

Genetic Determinants of Resistance among ESBL-Producing Enterobacteriaceae in Community and Hospital Settings in East, Central, and Southern Africa: A Systematic Review and Meta-Analysis of Prevalence

Background

The world prevalence of community and hospital-acquired extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is increasing tremendously. Bacteria harboring ESBLs are currently the number one critical pathogens posing a major threat to human health.

Objective

To provide a summary of molecular evidence on the prevalence of ESBL-producing Enterobacteriaceae (ESBL-E) and associated genes at community and hospital settings in East, Central, and Southern African countries.

Methods

We conducted a systematic literature search on PubMed and Google Scholar databases for the available molecular studies on ESBL-E in hospitals and community settings in East, Central, and Sothern Africa (ECSA). Published studies in English language involving gene characterization of ESBLs from human samples in hospital and community settings were included in the review, inception to November 2019. A random effect meta-analysis was performed to estimate the prevalence of ESBL-E.

Results

A total of 27 studies involving molecular characterization of resistance genes from 20,225 ESBL-E isolates were included in the analysis. Seventy-four percent of all studies were hospital based, 15% were based in community settings, and others were done in both hospital and community settings. Of all the studies, 63% reported E. coli as the dominant isolate among ESBL-E recovered from clinical samples and Klebsiella pneumoniae was reported dominant isolates in 33% of all studies. A random pooled prevalence of ESBL-E was 38% (95% CI = 24–53%), highest in Congo, 92% (95% CI = 90–94%), and lowest in Zimbabwe, 14% (95% CI = 9–20%). Prevalence was higher in hospital settings 41% (95% CI = 23–58%) compared to community settings 34% (95% CI = 8–60%). ESBL genes detected from clinical isolates with ESBL-E phenotypes in ECSA were those of Ambler molecular class A [1] that belongs to both functional groups 2be and 2d of Bush and Jacob classification of 2010 [2]. Majority of studies (n = 22, 81.5%) reported predominance of blaCTX-M gene among isolates, particularly CTX-M-15. Predictors of ESBL-E included increased age, hospital admissions, previous use of antibiotics, and paramedical use of herbs.

Conclusion

Few studies have been conducted at a molecular level to understand the genetic basis of increased resistance among members of ESBL-E in ECSA. Limited molecular studies in the ECSA region leave a gap in estimating the burden and risk posed by the carriage of ESBL genes in these countries. We found a high prevalence of ESBL-E most carrying CTX-M enzyme in ECSA with a greater variation between countries. This could be an important call for combined (regional or global) efforts to combat the problem of antimicrobial resistance (AMR) in the region. Antibiotic use and hospital admission increased the carriage of ESBL-E, while poor people contributed little to the increase of AMR due to lack of access and failure to meet the cost of healthcare compared to high income individuals.

Role played by the environment in the emergence and spread of antimicrobial resistance (AMR) through the food chain

The role of food-producing environments in the emergence and spread of antimicrobial resistance (AMR) in EU plant-based food production, terrestrial animals (poultry, cattle and pigs) and aquaculture was assessed. Among the various sources and transmission routes identified, fertilisers of faecal origin, irrigation and surface water for plant-based food and water for aquaculture were considered of major importance. For terrestrial animal production, potential sources consist of feed, humans, water, air/dust, soil, wildlife, rodents, arthropods and equipment. Among those, evidence was found for introduction with feed and humans, for the other sources, the importance could not be assessed. Several ARB of highest priority for public health, such as carbapenem or extended-spectrum cephalosporin and/or fluoroquinolone-resistant Enterobacterales (including Salmonella enterica), fluoroquinolone-resistant Campylobacter spp., methicillin-resistant Staphylococcus aureus and glycopeptide-resistant Enterococcus faecium and E. faecalis were identified. Among highest priority ARGs bla CTX -M, bla VIM, bla NDM, bla OXA -48-like, bla OXA -23, mcr, armA, vanA, cfr and optrA were reported. These highest priority bacteria and genes were identified in different sources, at primary and post-harvest level, particularly faeces/manure, soil and water. For all sectors, reducing the occurrence of faecal microbial contamination of fertilisers, water, feed and the production environment and minimising persistence/recycling of ARB within animal production facilities is a priority. Proper implementation of good hygiene practices, biosecurity and food safety management systems is very important. Potential AMR-specific interventions are in the early stages of development. Many data gaps relating to sources and relevance of transmission routes, diversity of ARB and ARGs, effectiveness of mitigation measures were identified. Representative epidemiological and attribution studies on AMR and its effective control in food production environments at EU level, linked to One Health and environmental initiatives, are urgently required.

Genome-Based Analysis of Klebsiella spp. Isolates from Animals and Food Products in Germany, 2013-2017

The increase in infections with multidrug-resistant and virulent Klebsiella pneumoniae (K. pneumoniae) strains poses a serious threat to public health. However, environmental reservoirs and routes of transmission for Klebsiella spp. that cause infections in humans and in livestock animals are not well understood. In this study, we aimed to analyze the distribution of antibiotic resistance genes and important virulence determinants (ybt, clb, iro, iuc, rmpA/A2) among 94 Klebsiella spp. isolates from different animal and food sources isolated between 2013 and 2017 in Germany. Antibiotic susceptibility testing was performed, and the genomes were sequenced by Illumina and Nanopore technology. Genetic relationships were assessed by conducting core genome multilocus sequence typing (cgMLST). Kleborate was used to predict resistance and virulence genes; Kaptive was used to derive the capsule types. The results revealed that 72 isolates (76.6%) belonged to the K. pneumoniae sensu lato complex. Within this complex, 44 known sequence types (STs), 18 new STs, and 38 capsule types were identified. Extended-spectrum beta-lactamase (ESBL) genes were detected in 16 isolates (17.0%) and colistin resistance in one (1.1%) K. pneumoniae isolate. Virulence genes were found in 22 K. pneumoniae isolates. Overall, nine (9.6%) and 18 (19.1%) isolates possessed the genes ybt and iuc, respectively. Notably, aerobactin (iuc lineage 3) was only detected in K. pneumoniae isolates from domestic pigs and wild boars. This study provides a snapshot of the genetic diversity of Klebsiella spp. in animals and food products in Germany. The siderophore aerobactin was found to be more prevalent in K. pneumoniae strains isolated from pigs than other sources. Further investigations are needed to evaluate if pigs constitute a reservoir for iuc lineage 3.

Waterborne Urinary Tract Infections: Have We Overlooked an Important Source of Exposure?

The presence of intestinal pathogenic Escherichia coli in drinking water is well recognized as a risk for diarrhea. The role of drinking water in extraintestinal infections caused by E. coli-such as urinary tract infections (UTIs)-remains poorly understood. Urinary tract infections are a leading cause of outpatient infections globally, with a lifetime incidence of 50-60% in adult women. We reviewed the scientific literature on the occurrence of uropathogenic E. coli (UPEC) in water supplies to determine whether the waterborne route may be an important, overlooked, source of UPEC. A limited number of studies have assessed whether UPEC isolates are present in drinking water supplies, but no studies have measured whether their presence in water may increase UPEC colonization or the risk of UTIs in humans. Given the prevalence of drinking water supplies contaminated with E. coli across the globe, efforts should be made to characterize UTI-related risks associated with drinking water, as well as other pathways of exposure.

Carbapenemase-producing Gram-negative bacteria in aquatic environments: a review

Antibiotic resistance is one of the greatest public-health challenges worldwide, especially with regard to Gram-negative bacteria (GNB). Carbapenems are the β-lactam antibiotics of choice with the broadest spectrum of activity and, in many cases, are the last-resort treatment for several bacterial infections. Carbapenemase-encoding genes, mainly carried by mobile genetic elements, are the main mechanism of resistance against carbapenems in GNB. These enzymes exhibit a versatile hydrolytic capacity and confer resistance to most β-lactam antibiotics. After being considered a clinical issue, increasing attention is being giving to the dissemination of such resistance mechanisms in the environment and especially through water. Aquatic environments are among the most significant microbial habitats on our planet, known as a favourable medium for antibiotic gene transfer, and they play a crucial role in the huge spread of drug resistance in the environment and the community. In this review, we present current knowledge regarding the spread of carbapenemase-producing isolates in different aquatic environments, which may help the implementation of control and prevention strategies against the spread of such dangerous resistant agents in the environment.

Hypervirulent Klebsiella pneumoniae of Lineage ST66-K2 Caused Tonsillopharyngitis in a German Patient

Hypervirulent Klebsiella pneumoniae (hvKp) is a novel pathotype that has been rarely described in Europe. This study characterizes a hvKp isolate that caused a community-acquired infection. The hypermucoviscous Klebsiella pneumoniae (K. pneumoniae) strain 18-0005 was obtained from a German patient with tonsillopharyngitis in 2017. Antibiotic susceptibility testing was performed and the genome was sequenced by Illumina and Nanopore technology. Whole genome data were analyzed by conducting core genome multilocus sequence typing (cgMLST) and single nucleotide polymorphism (SNP) analysis. Virulence genes were predicted by applying Kleborate. Phenotypic and whole genome analyses revealed a high similarity of the study isolate 18-0005 to the recently reported antibiotic-susceptible hvKp isolate SB5881 from France and the “ancestral” strain Kp52.145; both were assigned to the ST66-K2 lineage. Comparative genomic analysis of the three plasmids showed that the 18-0005 plasmid II differs from SB5881 plasmid II by an additional 3 kb integrated fragment of plasmid I. Our findings demonstrate the genetic flexibility of hvKp and the occurrence of a strain of the clonal group CG66-K2 in Germany. Hence, it emphasizes the need to improve clinical awareness and infection monitoring of hvKp.

Resistotyping and extended-spectrum beta-lactamase genes among Escherichia coli from wastewater treatment plants and recipient surface water for reuse in South Africa

The spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has increased in different environments. This study aimed to evaluate the patterns of antibiotic resistance and ESBL genes among E. coli isolates collected from wastewater and recipient surface water in South Africa. Fifteen samples containing nine wastewater and six river water samples were collected from a local wastewater treatment plant. The E. coli isolates were detected using standard microbiology methods. Antibiotic susceptibility testing was performed using disc diffusion agar. The occurrence of bla_CTX-M, bla_SHV and bla_TEM ESBL genes was investigated by PCR. Exactly 140 isolates were selected from the primary enumeration plates with a log₁₀ CFU/mL count that ranged from 4.1 to 4.2 (influent), 4.2 to 4.5 (biofilter) and 2.5 to 3.3 (effluent). The wastewater effluent showed an impact on the receiving water environment, as the treatment efficiency was 92% and the downstream log₁₀ CFU/mL count (range, 3.6–3.8 log₁₀ CFU/mL) was higher than the upstream count (range, 3.3–3.6 log₁₀ CFU/mL). Antibiotic testing results showed that 40% to 100% of E. coli isolates were resistant to ampicillin, penicillin, tetracycline and cefotaxime but susceptible to imipenem, meropenem and ciprofloxacin. A total of 40 studied isolates (28.6%) had both the bla_TEM and bla_CTX-M genes, while no bla_SHV was detected. The wastewater treatment plants contributed multidrug-resistant ESBL-producing E. coli isolates that can be potential environmental health risks. Regular monitoring policies are recommended to prevent the spread of antibiotic resistance in the region.

Multidrug-resistant enterobacteriaceae in coastal water: an emerging threat

Background

The environmental role of carbapenemase-producing Enterobacteriaceae (CPE) acquisition and infection in human disease has been described but not thoroughly investigated. We aimed to assess the occurrence of CPE in nearshore aquatic bodies.

Methods

Enterobacteriaceae were cultured from coastal and estuary water near Netanya, Israel in June and July of 2018. Bacteria were identified by VITEK2® and their antimicrobial susceptibility was tested according to the CLSI guidelines. Enterobacteriaceae genomes were sequenced to elucidate their resistome and carbapenemase types.

Results

Among other clinically relevant bacteria, four CPE (three Enterobacter spp and one Escherichia coli isolate) were isolated from two river estuaries (Poleg and Alexander Rivers) and coastal water at a popular recreational beach (Beit Yanai). Molecular analysis and genome sequencing revealed the persistent presence of rare beta-lactamase resistance genes, including bla_IMI-2 and a previously unknown bla_IMI-20 allele, which were not found among the local epidemiological strains. Genome comparisons revealed the high identity of riverine and marine CPE that were cultivated one month apart.

Conclusions

We show that CPE contamination was widespread in nearshore marine and riverine habitats. The high genome-level similarity of riverine and marine CPEs, isolated one month apart, hints at the common source of infection. We discuss the clinical implications of these findings and stress the urgent need to assess the role of the aquatic environment in CPE epidemiology.

The Hydric Environment: A Hub for Clinically Relevant Carbapenemase Encoding Genes

Carbapenems are β-lactams antimicrobials presenting a broad activity spectrum and are considered as last-resort antibiotic. Since the 2000s, carbapenemase producing Enterobacterales (CPE) have emerged and are been quickly globally spreading. The global dissemination of carbapenemase encoding genes (CEG) within clinical relevant bacteria is attributed in part to its location onto mobile genetic elements. During the last decade, carbapenemase producing bacteria have been isolated from non-human sources including the aquatic environment. Aquatic ecosystems are particularly impacted by anthropic activities, which conduce to a bidirectional exchange between aquatic environments and human beings and therefore the aquatic environment may constitute a hub for CPE and CEG. More recently, the isolation of autochtonous aquatic bacteria carrying acquired CEG have been reported and suggest that CEG exchange by horizontal gene transfer occurred between allochtonous and autochtonous bacteria. Hence, aquatic environment plays a central role in persistence, dissemination and emergence of CEG both within environmental ecosystem and human beings, and deserves to be studied with particular attention.

Molecular Epidemiology of Carbapenemases in Enterobacteriales from Humans, Animals, Food and the Environment

The Enterobacteriales order consists of seven families including Enterobacteriaceae, Erwiniaceae, Pectobacteriaceae, Yersiniaceae, Hafniaceae, Morganellaceae, and Budviciaceae and 60 genera encompassing over 250 species. The Enterobacteriaceae is currently considered as the most taxonomically diverse among all seven recognized families. The emergence of carbapenem resistance (CR) in Enterobacteriaceae caused by hydrolytic enzymes called carbapenemases has become a major concern worldwide. Carbapenem-resistant Enterobacteriaceae (CRE) isolates have been reported not only in nosocomial and community-acquired pathogens but also in food-producing animals, companion animals, and the environment. The reported carbapenemases in Enterobacteriaceae from different sources belong to the Ambler class A (bla_KPC), class B (bla_IMP, bla_VIM, bla_NDM), and class D (bla_OXA-48) β-lactamases. The carbapenem encoding genes are often located on plasmids or associated with various mobile genetic elements (MGEs) like transposons and integrons, which contribute significantly to their spread. These genes are most of the time associated with other antimicrobial resistance genes such as other β-lactamases, as well as aminoglycosides and fluoroquinolones resistance genes leading to multidrug resistance phenotypes. Control strategies to prevent infections due to CRE and their dissemination in human, animal and food have become necessary. Several factors involved in the emergence of CRE have been described. This review mainly focuses on the molecular epidemiology of carbapenemases in members of Enterobacteriaceae family from humans, animals, food and the environment.

Characterization of water treatment-resistant and multidrug-resistant urinary pathogenic Escherichia coli in treated wastewater

A growing body of evidence has demonstrated that extraintestinal pathogenic E. coli (ExPEC), such as the urinary pathogenic E. coli (UPEC), are common constituents of treated wastewater, and therefore represent a potential public health risk. However, no single virulence gene, or set of virulence genes, can be used to conclusively identify this genetically diverse pathotype. As such we sought to identify and characterize the public health relevance of potential UPEC found in treated sewage/wastewater using a comparative genomics approach. Presumptive wastewater UPEC (W-UPEC) were initially identified by virulence gene screening against 5 virulence genes, and for which isolates containing ≥3 virulence genes were whole genome sequenced (n = 24). Single nucleotide polymorphic (SNP) spanning tree analysis demonstrated that many of these wastewater UPEC (WUPEC) were virtually identical at the core genome (0.4 Mbp) when compared to clinical UPEC (C-UPEC) sequences obtained from NCBI, varying by as little as 1 SNP. Remarkably, at the whole genome level, W-UPEC isolates displayed >96% whole genome similarity to C-UPEC counterparts in NCBI, with one strain demonstrating 99.5% genome similarity to a particular C-UPEC strain. The W-UPEC populations were represented by sequence types (ST) known to be clinically important, including ST131, ST95, ST127 and ST640. Many of the W-UPEC carried the exact same complement of virulence genes as their most closely related C-UPEC strains. For example, O25b-ST131 W-UPEC strains possessed the same 80 virulence genes as their most closely related C-UPEC counterparts. Concerningly, W-UPEC strains also carried a plethora of antibiotic resistance genes, and O25b-ST131strains were designated as extended spectrum beta-lactamase (ESBL) producing E. coli by both genome profiling and phenotypic resistance testing. W-UPEC ST131 strains were found in the effluents of a single treatment plant at different times, as well as different wastewater treatment plants, suggesting a differentially ability to survive wastewater treatment. Indeed, in sewage samples treated with chlorine doses sufficient for inducing a ∼99.99% reduction in total E. coli levels, UPEC represented a significant proportion of the chlorine-resistant population. By contrast, no Shiga toxin-producing E. coli were observed in these chlorinated sewage libraries. Our results suggest that clinically-relevant UPEC exist in treated wastewater effluents and that they appear to be specifically adapted to survive wastewater treatment processes.

Detection of Carbapenem-Resistant Genes in Escherichia coli Isolated from Drinking Water in Khartoum, Sudan

Waterborne Escherichia coli are a major reservoir of antimicrobial resistance (AMR). Carbapenem-resistance, especially when mediated by transferable carbapenemase-encoding genes, is spreading worldwide and causing dramatically limiting treatment options. In our country, studies for the detection of carbapenem resistance in drinking water do not exist; therefore, this work was carried out to determine the prevalence of carbapenem-resistant genes “bla_KPC, bla_IMP, bla_NDM, bla_SPM, bla_VIM, and bla_OXA-48” among Escherichia coli isolated from drinking water in Khartoum, Sudan. A total of forty-five E. coli bacteria were isolated from different sources of drinking water. Antimicrobial susceptibility testing was performed using imipenem (10 mg/disc), gentamicin (10 mg/disc), ceftriaxone (30 mg/disc), ciprofloxacin (5 mg/disc), chloramphenicol (30 mg/disc), and tetracycline (30 mg/disc). “Sensitive” or “resistant” patterns of E. coli were judged using antibiotic minimum inhibitory concentration (MIC). Bacterial genomic DNA was extracted by the boiling method, and then multiplex polymerase chain reaction was performed to detect the carbapenemase genes (bla_KPC, bla_IMP, bla_NDM, bla_SPM, bla_VIM, and bla_OXA-48). Multiplex PCR assays confirmed the presence of carbapenemase genes in 28% of all water isolates. OXA-48 gene was the most predominant gene, detected in 15.5% of the isolates. The bla_KPC and bla_SPM genes were also detected in 4.4% and 8.8% of the isolates, respectively. However, the isolates were negative for bla_NDM, bla_VIM, and bla_IMP genes. The isolates showed a high rate of tetracycline resistance (97.7%), followed by gentamicin (57.7%), ciprofloxacin (46.6%), ceftriaxone (35.5%), and chloramphenicol (31.1%). In conclusion, this study confirmed for the first time the presence of E. coli carried carbapenem-resistant genes in the drinking water of Khartoum state, Sudan. These isolates commonly carried OXA-48 (7/45), followed by SPM (4/45) and KPC (2/45).