Extended-Spectrum β-Lactamases (ESBL): Challenges and Opportunities

Evolutionary relationships and genetic diversity in the BlaTEM gene among selected gram-negative bacteria

This study investigates the genetic diversity and evolutionary relationships of the blaTEM gene, a major determinant of beta-lactam antibiotic resistance. We analyzed nucleotide sequences of 32 β-lactamase-producing strains from Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, and Acinetobacter baumannii obtained from public databases. Sequence analysis revealed 32 distinct sequences with 298 segregating sites and 303 mutations, indicating substantial genetic variability. A high level of haplotype diversity was observed, with 24 distinct haplotypes, reflecting evolutionary pressures and horizontal gene transfer. Phylogenetic analysis showed clear clades, suggesting the evolutionary relationships among blaTEM variants and interspecies gene transfer. The resistance profiles correlated with the genetic findings, particularly mutations. This analysis draws attention to the ongoing adaptive evolution of antibiotic resistance mechanisms, as well as the need for continued monitoring and novel therapeutic strategies. Further research with larger sample sizes and functional validation is needed to fully understand the implications of these variants in antibiotic resistance.

Construction and validation of an interpretable XGBoost machine learning model to predict ESBL positivity rates based on urinalysis data

BACKGROUND

Microbiological culture and drug susceptibility testing of urine samples have lengthy turnaround times, increasing the risk of extended-spectrum β-lactamase (ESBL)-positive urinary tract infection (UTI) patients progressing to sepsis.

OBJECTIVE

To develop an efficient machine learning model for the identification of ESBL positivity in UTI patients.

METHODS

This retrospective study included 528 samples that had undergone drug susceptibility testing, based on inclusion and exclusion criteria. Variables were screened using Lasso regression, with 70% of the samples used to construct nine machine learning models (XGBClassifier, LogisticRegression, LGBMClassifier, AdaBoostClassifier, SVC, MLPClassifier, ComplementNB, GaussianNB, and GradientBoostingClassifier). Model selection was based on criteria including accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), F1 score, Kappa score, and Area Under the Curve (AUC). The best model type was identified through ten-fold cross-validation, which was then built using the remaining 30% of the data as a test set. Interpretations of predictive results were provided using the SHAP model, clarifying the impact of each feature on predictions and enhancing model transparency and interpretability.

RESULTS

The variables selected by the Lasso regression model are as follows: gender + urinary protein + urobilinogen + leukocytes + occult blood + age + pH + specific gravity + leukocyte count + erythrocyte count + epithelial cell count + cast count.The XGBoost model outperformed others in ten-fold cross-validation, with scores on the validation set as follows: AUC (95%CI): 0.924 (0.860-0.989); cutoff: 0.664(0.637-0.690); accuracy: 0.862(0.839-0.885); sensitivity: 0.9(0.879-0.920); specificity: 0.725(0.618-0.832); PPV: 0.923(0.896-0.950); NPV: 0.667(0.626-0.707); F1 score: 0.911(0.896-0.925); Kappa: 0.603(0.527-0.679). The final model achieved an AUC of 0.968 and accuracy of 0.943 on the test set.

CONCLUSION

This study developed a rapid and efficient machine learning model capable of identifying ESBL positivity based solely on routine urine test data.

Multinational comparison of the detection of extended-spectrum beta-lactamase genes in healthy resident feces

The spread of antimicrobial-resistant bacteria, especially in developing countries, is a critical healthcare issue. Among these, extended-spectrum beta-lactamase (ESBL)-producing bacteria are particularly concerning due to their resistance to third- and fourth-generation cephalosporins. Traditional methods for assessing bacterial resistance involve culturing bacteria on selective media from fecal samples, which may lead to selection bias. Alternatively, real-time PCR allows for detecting resistance genes directly from fecal DNA, providing a broader view of resistant bacteria. In this study, we evaluated the utility of a real-time PCR assay targeting ESBL-producing genes as a comprehensive detection method for ESBL-producing resistant bacteria in fecal samples. Additionally, we conducted a multinational comparative analysis of the colonization status of residents using this approach. The study analyzed ESBL genes in fecal samples from 161 residents in four countries: Ecuador, Ghana, Vietnam, and Japan. Samples from Ecuador, Ghana, and Vietnam, where ESBL carriage was notably high, revealed gene variations by country, with blaTEM genes being most common except in Ghana, where blaSHV genes predominated. These variations suggest that different bacterial hosts carry ESBL genes across countries. Quantitative PCR results further highlight that blaTEM is the most abundant ESBL gene. Although gene presence does not confirm antibiotic resistance, these findings underline significant ESBL carriage in low- and middle-income countries. The study emphasizes that gene detection in fecal samples is valuable for understanding resistant bacteria spread in communities.IMPORTANCEThe rise of antimicrobial-resistant bacteria, particularly extended-spectrum beta-lactamase (ESBL)-producing strains, poses a serious threat to healthcare in developing countries. This study utilized real-time PCR to detect ESBL genes directly from fecal DNA of 161 participants across four countries, offering a comprehensive analysis without the biases of traditional culture-based methods. High ESBL gene carriage rates were found in Ecuador, Ghana, and Vietnam, with regional differences in gene prevalence: blaTEM dominated in most countries, while blaSHV was most frequent in Ghana. These results highlight the widespread community-level dissemination of ESBL genes in low- and middle-income countries, underscoring the importance of using gene detection as a tool for assessing the spread of resistant bacteria.

Management practices and mortality predictors among Klebsiella pneumoniae infections across Lebanese hospitals: a multicenter retrospective study

BACKGROUND

Klebsiella pneumoniae is a significant cause of both community-acquired and nosocomial infections, leading to high morbidity and mortality rates. The increasing antimicrobial resistance among K. pneumoniae strains poses a critical challenge to effective treatment. This study aimed to assess the appropriateness of initial antimicrobial therapy, determine the 30-day all-cause mortality rate, and identify predictors of mortality among patients infected with K. pneumoniae in Lebanese hospitals.

METHODS

A multicenter retrospective observational study was conducted across three university hospitals in Beirut, Lebanon. The study included hospitalized adult patients with confirmed K. pneumoniae infections. Kaplan-Meier survival analysis and log-rank tests were used to analyze time-to-mortality. Binary logistic regression was performed to identify predictors of mortality.

RESULTS

Of 2,655 cases screened, 410 patients were enrolled, and 395 cases were included in the final analysis of the 30-day mortality after excluding those lost to follow-up. Nearly one-third of the isolates (36.8%) were extended-spectrum β-lactamase (ESBL)-producing, while 6.8% were carbapenem-resistant K. pneumoniae (CRKP). The most commonly prescribed empirical antibiotics were meropenem (31.7%), amikacin (28.5%), and ceftriaxone (22.2%). Around one-third of the patients (32.9%) received inappropriate initial antimicrobial therapy. The 30-day mortality rate was 14.4%. Main predictors significantly associated with mortality in patients with K. pneumoniae infection were solid cancer (adjusted odds ratio [AOR] = 7.82, P < 0.01), coronary artery disease (AOR = 4.81, P = 0.01), age ≥ 65 years (AOR = 4.22, P = 0.02), type II diabetes mellitus (AOR = 3.96, P = 0.01), receiving inappropriate initial antimicrobial therapy (AOR = 2.96, P = 0.02), infection with CRKP isolates (AOR = 2.53, P = 0.03), and having a higher Charlson comorbidity index (AOR = 1.61, P = 0.001).

CONCLUSIONS

The study highlights the critical need for effective antimicrobial stewardship and tailored infection control protocols to mitigate the high resistance rates and improve patient outcomes in Lebanon. Emphasis should be placed on enhancing the monitoring of local resistance patterns and using these data to guide the selection of appropriate empirical therapy to reduce mortality associated with K. pneumoniae infections.

Therapeutic Potential of Novel Phages with Antibiotic Combinations Against ESBL-Producing and Carbapenem-Resistant Escherichia coli

OBJECTIVES

The emergence of extended-spectrum β-lactamase (ESBL)-producing E. coli and carbapenem-resistant E. coli (CREC) is a significant global health challenge. This study focuses on isolating and characterizing two novel phages, EC.W1-9 and EC.W15-4, and investigating their efficacy with antibiotics against these resistant E. coli.

METHODS

In vivo experiments were conducted using BALB/c mice, and E.coli isolates were collected, cultured, and evaluated for antibiotic susceptibility. Phages were isolated from hospital sewage and prepared to infect the E. coli.

RESULTS

The isolated phages, EC.W1-9 and EC.W15-4, belonged to the Podoviridae and Straboviridae families, and lack integrase or toxin-coding genes, indicating safety for therapeutic use. The combination of these phages significently enhanced their lytic ability, lysing 61.7% of 60 E. coli isolates, compared to 41.6%-55% lysis by individual phages. Furthermore, the phage combination demonstrated 100% susceptibility against different E. coli sequence types, including ST73, ST648, ST2311, ST405, ST7962, ST131, ST13003, and ST167. Additionally, synergy between antibiotics and phage combinations improved susceptibility rates to 73.3% for ESBL producers and 54% for CREC. The combined treatment of isolated phages and antibiotics significantly increased survival rates in BALB/c mice exposed to resistant STs of E.coli, including ST131, ST648, and ST410. Survival rates against ST131 increased by approximately 75% and 50% compared to treatment individual phages. Combined treatment with two phages and antibiotics resulted in 75-100% survival against E. coli ST410 and 100% survival against ST648 CONCLUSIONS: This study highlights the therapeutic importance of phage and phage-antibiotic combinations in combating ESBL-producing E. coli and CREC isolates.

Piperacillin/tazobactam versus carbapenems for 30-day mortality in patients with ESBL-producing Enterobacterales bloodstream infections: a retrospective, multicenter, non-inferiority, cohort study

PURPOSE

Antimicrobial resistance increases with the use of broad-spectrum antibiotics. Studies evaluating antibiotic stewardship are in high demand. Is piperacillin/tazobactam non-inferior to carbapenems regarding 30-day mortality among patients with bloodstream infections caused by extended-spectrum beta-lactamase-producing Enterobacterales?

METHODS

This retrospective, multicenter, non-inferiority, cohort study assessed adult patients with bloodstream infections caused by extended-spectrum beta-lactamase-producing Enterobacterales in southern Sweden from 2013 to 2022. Patients were categorized according to the first therapy they received two consecutive doses of (piperacillin/tazobactam or a carbapenem). The primary outcome was 30-day all-cause mortality, measured from when the positive blood cultures were taken. The absolute risk difference for this outcome was calculated for all patients, and two propensity score matched cohorts (empirical and effective), with two different delta limits (5% and 2%). Secondary outcomes included intensive care unit admission, early clinical response, superinfections, relapsed infection and one-year mortality.

RESULTS

A total of 644 patients were included. In the piperacillin/tazobactam group, 26/309 patients met the primary outcome, compared to 27/335 patients in the carbapenem group. The absolute risk difference (-0.4%) was statistically significant in the propensity score matched empirical cohort [1-sided 97.5% confidence interval]: -∞ to 4.0, p = 0.008). Piperacillin/tazobactam was non-inferior to carbapenems for all the secondary outcomes in the same cohort, except for the early clinical response.

CONCLUSION

Our findings indicate that piperacillin/tazobactam is non-inferior to carbapenems for treating extended-spectrum beta-lactamase-producing Enterobacterales bloodstream infections, with an acceptable 5% increase in 30-day mortality. We suggest that piperacillin/tazobactam should be used more frequently to decrease antimicrobial resistance.

Potential Inhibitory Effect of the Peptide Melittin Purified from Apis mellifera Venom on CTX-M-Type Extended-Spectrum β-Lactamases of Escherichia coli

Background. Extended-spectrum β-lactamases (ESBLs) hydrolyze nearly all β-lactam antibiotics, affecting one of the most important groups of antimicrobials used in Gram-negative infections. Among them, CTX-M is the most widespread type of ESBL. This study aimed to evaluate the hydrolytic activity of CTX-M-type ESBLs following exposure to the antimicrobial peptide Melittin. Methods. Melittin was purified from Apis mellifera venom through ultrafiltration and characterized by SDS-PAGE. The minimum inhibitory concentration (MIC) of Melittin against ESBL-producing E. coli was determined by the broth microdilution method. The inhibition of ESBL's hydrolytic activity following exposure to sub-MIC doses of Melittin was quantified using a kinetic assay based on hydrolyzed nitrocefin. Additionally, the effect of Melittin on the expression of the blaCTX-M gene was evaluated via RT-PCR. Results. The peptide fraction of Apitoxin smaller than 10 kDa exhibited a protein band corresponding to Melittin, devoid of higher molecular weight proteins. The MIC of Melittin ranged from 50 to 80 µg/mL. Exposure to Melittin at sub-MIC doses significantly inhibited ESBL hydrolytic activity, reducing it by up to 67%. However, the transcription of the blaCTX-M gene in the presence of Melittin revealed no significant changes. Conclusions. Melittin is able to inhibit ESBL's hydrolytic activity but not blaCTX-M transcription possibly indicating an effect at the translational or post-translational level.

Public health threat of antimicrobial resistance and virulence genes in Escherichia coli from human-chicken transmission in Egypt

Escherichia coli (E. coli) infections cause significant losses in the poultry industry and pose zoonotic risks due to rising antimicrobial resistance (AMR) and virulence factors. This study investigates E. coli prevalence, AMR, and virulence genes (papC, vgrG1, iss) in Egyptian chickens and farm workers. A total of 35 dead chickens from 14 flocks and 17 farm workers urine samples were examined bacteriologically to investigate E. coli presence followed by biochemical identification. Antimicrobial susceptibility testing was performed on 14 antibiotics using the disk diffusion method on Mueller-Hinton agar, following 'Clinical and Laboratory Standards Institute (CLSI) (2020) guidelines with Extended-spectrum β-lactamase (ESBL) activity evaluated via the Double Disc Synergy Test (DDST) with ceftazidime, cefotaxime, and their clavulanate combinations following CLSI protocols. virulence genes were detected through polymerase chain reaction (PCR) and phylogenetic analysis of the vgrG1 gene evaluated genetic relatedness between the chicken and human isolates. The study analysed 52 samples, identifying E. coli in 18 chicken organs (51.4%) and 11 human urine samples (64.7%), with no significant difference. various antimicrobic sensitivity profiles were identified phenotypically among all isolates in which 29 isolates, 58.6% were ESBL-producing, and 96.5% exhibited multidrug resistance (MDR), with chicken isolates showing higher resistance overall. virulence genes were detected in similar proportions across the isolates highlighting significant public health risks due to resistant and virulent E. coli. This study emphasized the public health risks of multidrug-resistant E. coli with virulence genes, highlighting potential zoonotic transmission and antibiotic use and food safety.

Antimicrobial resistance: Linking molecular mechanisms to public health impact

BACKGROUND

Antimicrobial resistance (AMR) develops into a worldwide health emergency through genetic and biochemical adaptations which enable microorganisms to resist antimicrobial treatment. β-lactamases (blaNDM, blaKPC) and efflux pumps (MexAB-OprM) working with mobile genetic elements facilitate fast proliferation of multidrug-resistant (MDR) and exttreme drug-resistant (XDR) phenotypes thus creating major concerns for healthcare systems and community health as well as the agricultural sector.

OBJECTIVES

The review dissimilarly unifies molecular resistance pathways with public health implications through the study of epidemiological data and monitoring approaches and innovative therapeutic solutions. Previous studies separating their attention between molecular genetics and clinical outcomes have been combined into our approach which delivers an all-encompassing analysis of AMR.

KEY INSIGHTS

The report investigates the resistance mechanisms which feature enzymatic degradation and efflux pump overexpression together with target modification and horizontal gene transfer because these factors represent important contributors to present-day AMR developments. This review investigates AMR effects on hospital and community environments where it affects pathogens including MRSA, carbapenem-resistant Klebsiella pneumoniae, and drug-resistant Pseudomonas aeruginosa. This document explores modern AMR management methods that comprise WHO GLASS molecular surveillance systems and three innovative strategies such as CRISPR-modified genome editing and bacteriophage treatments along with antimicrobial peptides and artificial intelligence diagnostic tools.

CONCLUSION

The resolution of AMR needs complete scientific and global operational methods alongside state-of-the-art therapeutic approaches. Worldwide management of drug-resistant infection burden requires both enhanced infection prevention procedures with next-generation antimicrobial strategies to reduce cases effectively.

Antibiotic Considerations in the Treatment of Maternal Sepsis

Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response to infection, remains the third leading cause of maternal mortality globally. Pregnancy-associated physiological adaptations predispose pregnant individuals to infection, impair maternal response to infection, affect antibiotic pharmacokinetics and metabolism, and complicate diagnosing infections and sepsis. Therefore, it is tantamount that clinicians readily recognize maternal sepsis and understand antibiotic regimens and treatment principles to avoid adverse maternal outcomes. In this article, we present an overview of the diagnosis and management of maternal sepsis and the physiological changes in pregnancy that alter antibiotic pharmacokinetics. Common microorganisms implicated in maternal sepsis are discussed with an emphasis on E. coli and Group A Streptococcus due to their prevalence and morbidity in the pregnant population. Lastly, we provide an overview of commonly used antibiotics and dosage recommendations in the treatment of maternal infection and sepsis.

Characterizing the co-existence of metallo-β-lactamase-producing and extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates in community wastewater samples of Dhaka, Bangladesh

Escherichia coli and Klebsiella pneumoniae isolates with multiple antibiotic-resistance genes in wastewater pose serious public health risks, as they can potentially contaminate the food and water supply. The main aim of this study was to isolate and identify E. coli and K. pneumoniae from community wastewater samples, and determine their antibiotic-resistance profiles and their antibiotic-resistant genes. From the northern part of Dhaka, Bangladesh, 36 wastewater samples were collected across 11 different areas, which were then serially diluted, and cultured using selective media. Isolates were identified via polymerase chain reaction. Out of the 197 isolates identified, E. coli and K. pneumoniae accounted for 55.8% (n = 110) and 44.2% (n = 87), respectively. Antibiotic susceptibility tests revealed multidrug resistance (MDR) in 30% of E. coli and 35.56% of K. pneumoniae isolates. Among E. coli, the prevalence of antibiotic-resistance genes included blaNDM-1 (8.9%), blaSHV (13.9%), and blaCTX-M (7.6%). In K. pneumoniae, the percentages were blaNDM-1 (12.8%), blaSHV (4.3%), and blaCTX-M (5.0%). Co-existence of multiple antibiotic-resistance genes was observed in 4.54% of E. coli isolates (n = 5) and 5.74% of K. pneumoniae isolates (n = 5). This suggests the escalating issue of infectious species becoming increasingly resistant to antibiotics in wastewater systems.

Serogrouping and Molecular Characterization of ESBL-Producing Avian Pathogenic Escherichia coli from Broilers and Turkeys with Colibacillosis in Algeria

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): blaCTX-M-1 (14), blaCTX-M-15 (2), and blaSHV-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.

Resistance Genes and Virulence Factor Genes in Coagulase-Negative and Positive Staphylococci of the Staphylococcus intermedius Group (SIG) Isolated from the Dog Skin

Staphylococci are common pathogens in dogs, causing a variety of dermatological problems. This study aimed to characterize the prevalence, antibiotic resistance, and biofilm-forming potential of Staphylococcus species isolated from the skin of shelter dogs. Overall, 108 samples were collected from the hairless skin areas of dogs in a shelter over one year. Isolates were cultured using standard microbiological methods and identified through biochemical testing, MALDI-TOF MS, and multiplex PCR. A total of 67 Staphylococcus isolates were identified, with S. pseudintermedius being the most prevalent. Antibiotic susceptibility was assessed using disk diffusion and MIC methods, revealing high resistance to ampicillin, erythromycin, and tetracycline. Notably, 12 multidrug-resistant SIG (S. intermedius group; S. pseudintermedius) and 4 CoNS strains (coagulase-negative staphylococci; S. equorum) were identified. Biofilm production was evaluated using a crystal violet assay, showing variable biofilm-forming capabilities among isolates and PCR, to confirm genes associated with biofilm formation. These findings highlight the presence of multidrug-resistant Staphylococcus species in shelter dogs, emphasizing the need for careful monitoring and antibiotic stewardship to manage potential risks to both animal and human health.

Metagenomic Insights into the Diverse Antibiotic Resistome of Non-Migratory Corvidae Species on the Qinghai-Tibetan Plateau

Antibiotic resistance represents a global health crisis with far-reaching implications, impacting multiple domains concurrently, including human health, animal health, and the natural environment. Wild birds were identified as carriers and disseminators of antibiotic-resistant bacteria (ARB) and their associated antibiotic resistance genes (ARGs). A majority of studies in this area have concentrated on migratory birds as carriers for the spread of antibiotic resistance over long distances. However, there has been scant research on the resistome of non-migratory Corvidae species that heavily overlap with human activities, which limits our understanding of antibiotic resistance in these birds and hinders the development of effective management strategies. This study employed a metagenomics approach to examine the characteristics of ARGs and mobile genetic elements (MGEs) in five common Corvidae species inhabiting the Qinghai-Tibetan Plateau. The ARGs were classified into 20 major types and 567 subtypes. Notably, ARGs associated with multidrug resistance, including to macrolide-lincosamide-streptogramins, tetracyclines, beta-lactam, and bacitracin, were particularly abundant, with the subtypes acrB, bacA, macB, class C beta-lactamase, and tetA being especially prevalent. A total of 5 types of MGEs (166 subtypes) were identified across five groups of crows, and transposase genes, which indicated the presence of transposons, were identified as the most abundant type of MGEs. Moreover, some common opportunistic pathogens were identified as potential hosts for these ARGs and MGEs. Procrustes analysis and co-occurrence network analysis showed that the composition of the gut microbiota shaped the ARGs and MGEs, indicating a substantial association between these factors. The primary resistance mechanisms of ARGs in crows were identified as multidrug efflux pumps, alteration of antibiotic targets, and enzymatic inactivation. High-risk ARGs which were found to potentially pose significant risks to public health were also analyzed and resulted in the identification of 81 Rank I and 47 Rank II ARGs. Overall, our study offers a comprehensive characterization of the resistome in wild Corvidae species, enhancing our understanding of the potential public health risks associated with these birds.

Genomic Characterization of Extremely Antibiotic-Resistant Strains of Pseudomonas aeruginosa Isolated from Patients of a Clinic in Sincelejo, Colombia

Pseudomonas aeruginosa is an opportunistic pathogen classified as a priority and a great public health concern; therefore, this research focuses on the genomic characterization of extremely resistant strains of P. aeruginosa isolated from patients in a clinic in Sincelejo, Colombia. Seven strains were analyzed by whole genome sequencing using the Illumina NovaSeq platform, with a focus on the identification of resistance genes and virulence factors through the CARD and VFDB databases. An ANI (Average Nucleotide Identity) analysis was carried out to determine the genetic relationship between the strains, complemented by a phylogenomic analysis to place the strains in different evolutionary clades. The results revealed that six of the strains are of Colombian origin, while one strain (547256) belongs to the high-risk clone ST773, previously unidentified in Colombia. Genome size ranged from 6 to 7.4 Mbp, indicating differences in genetic content among strains. Phylogenomic analysis confirmed that five strains belong to a multidrug-resistant (MDR) group, while one strain (572897) showed high alignment with a laboratory strain, and strain 547256 was not associated with any specific clade. Clinically, 100% of strains showed carbapenem resistance, resistance genes, and virulence factors that make them difficult to treat. This study provides key insights into the genetic diversity and resistance patterns of P. aeruginosa in this region, underscoring the need to monitor high-risk clones and optimize therapeutic strategies.

Early-life antibiotic exposures: Paving the pathway for dysbiosis-induced disorders

Microbiota encompasses a diverse array of microorganisms inhabiting specific ecological niches. Gut microbiota significantly influences physiological processes, including gastrointestinal motor function, neuroendocrine signalling, and immune regulation. They play a crucial role in modulating the central nervous system and bolstering body defence mechanisms by influencing the proliferation and differentiation of innate and adaptive immune cells. Given the potential consequences of antibiotic therapy on gut microbiota equilibrium, there is a need for prudent antibiotic use to mitigate associated risks. Observational studies have linked increased antibiotic usage to various pathogenic conditions, including obesity, inflammatory bowel disease, anxiety-like effects, asthma, and pulmonary carcinogenesis. Addressing dysbiosis incidence requires proactive measures, including prophylactic use of β-lactamase drugs (SYN-004, SYN-006, and SYN-007), hydrolysing the β-lactam in the proximal GIT for maintaining intestinal flora homeostasis. Prebiotic and probiotic supplementations are crucial in restoring intestinal flora equilibrium by competing with pathogenic bacteria for nutritional resources and adhesion sites, reducing luminal pH, neutralising toxins, and producing antimicrobial agents. Faecal microbiota transplantation (FMT) shows promise in restoring gut microbiota composition. Rational antibiotic use is essential to preserve microflora and improve patient compliance with antibiotic regimens by mitigating associated side effects. Given the significant implications on gut microbiota composition, concerted intervention strategies must be pursued to rectify and reverse the occurrence of antibiotic-induced dysbiosis. Here, antibiotics-induced microbiota dysbiosis mechanisms and their systemic implications are reviewed. Moreover, proposed interventions to mitigate the impact on gut microflora are also discussed herein.

Exploring the intricacies of antimicrobial resistance: Understanding mechanisms, overcoming challenges, and pioneering innovative solutions

Antimicrobial resistance (AMR) poses a growing global threat. This review examines AMR from diverse angles, tracing the story of antibiotic resistance from its origins to today's crisis. It explores the rise of AMR, from its historical roots to the urgent need to counter this escalating menace. The review explores antibiotic classes, mechanisms, resistance profiles, and genetics. It details bacterial resistance mechanisms with illustrative examples. Multidrug-resistant bacteria spotlight AMR's resilience. Modern AMR control offers hope through precision medicine, stewardship, combination therapy, surveillance, and international cooperation. Converging traditional and innovative treatments presents an exciting frontier as novel compounds seek to enhance antibiotic efficacy. This review calls for global unity and proactive engagement to address AMR collectively, emphasizing the quest for innovative solutions and responsible antibiotic use. It underscores the interconnectedness of science, responsibility, and action in combatting AMR. Humanity faces a choice between antibiotic efficacy and obsolescence. The call is clear: unite, innovate, and prevail against AMR.

Mechanisms of Antimicrobial Resistance in Klebsiella: Advances in Detection Methods and Clinical Implications

Klebsiella spp. are ubiquitous gram-negative bacteria, commonly present in natural environments and as part of the human microbiota. Klebsiella is involved in the occurrence and development of many diseases, and effective antibiotics for it have attracted the attention of researchers. In recent years, its multi-drug resistance, particularly to carbapenems and β-lactam antibiotics, has posed significant challenges to clinical treatment. Therefore, a comprehensive understanding of the resistance mechanisms of Klebsiella, along with the enhancement of detection methods, is crucial for effectively controlling the spread of drug-resistant strains and guiding individualized clinical treatment. This paper systematically reviews the epidemiological characteristics, resistance mechanisms, detection methods, and treatment strategies of Klebsiella, aiming to provide new insights for the clinical management of this pathogen.

Extended-spectrum beta-lactamase-producing Escherichia coli through the poultry production chain in Argentina

The presence of extended-spectrum β-lactamases-producing Escherichia coli (ESBL-EC) in food production systems is a public health problem, since they can be transmitted to humans. The aims of this study were to isolate and characterize ESBL-EC from poultry farms located in Argentina. Resistances to β-lactams (first-, third-, and fourth-generation cephalosporins, penicillin), tetracyclines, quinolones, sulfonamides, phosphonates and aminoglycosides were found among the 40 ESBL-EC isolates. In addition, a wide range of antimicrobial resistance profiles were identified. The most frequent accompanying resistance to non-β-lactam antibiotics was tetracycline (97.5 %), followed by ciprofloxacin (82.5 %). All ESBL-EC isolates were multidrug resistant, and were grouped into four blaCTX-M groups: blaCTX-M-2 (75 %), followed by blaCTX-M-1, blaCTX-M-1/blaCTX-M-2, and blaCTX-M-2/blaCTX-M-8. Of the 40 ESBL-EC isolates, 31 carried genes encoding integrase, 28 were positive for intI1- qacEΔ1- sul1, three for intI1, three were identified as Verocytotoxin-producing E. coli (VTEC) and most of the studied isolates belonged to the phylogroup E. This study reports the presence of CTX-M in E. coli obtained from poultry production in Argentina and that CTX-M-2 was the main mechanism responsible for third generation cephalosporins resistance. Also, showed that apparently healthy chickens in Argentina harbor commensal multidrug-resistant (MDR) ESBL-EC, with resistances to antibiotics of critical importance for human and veterinary medicine.

Current innovations in mRNA vaccines for targeting multidrug-resistant ESKAPE pathogens

The prevalence of multidrug-resistant (MDR) ESKAPE pathogens, including Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, represents a critical global public health challenge. In response, mRNA vaccines offer an adaptable and scalable platform for immunotherapy against ESKAPE pathogens by encoding specific antigens that stimulate B-cell-driven antibody production and CD8+ T-cell-mediated cytotoxicity, effectively neutralizing these pathogens and combating resistance. This review examines recent advancements and ongoing challenges in the development of mRNA vaccines targeting MDR ESKAPE pathogens. We explore antigen selection, the nuances of mRNA vaccine technology, and the complex interactions between bacterial infections and antibiotic resistance. By assessing the potential efficacy of mRNA vaccines and addressing key barriers to their paraclinical implementation, this review highlights the promising function of mRNA-based immunization in combating MDR ESKAPE pathogens.

Proteomic Diversity in Bacteria: Insights and Implications for Bacterial Identification

Mass spectrometry-based proteomics has revolutionized bacterial identification and elucidated many molecular mechanisms underlying bacterial growth, community formation, and drug resistance. However, most research has been focused on a few model bacteria, overlooking bacterial diversity. In this study, we present the most extensive bacterial proteomic resource to date, covering 303 species, 119 genera, and five phyla with over 636,000 unique expressed proteins, confirming the existence of over 38,700 hypothetical proteins. Accessible via the public resource ProteomicsDB, this dataset enables quantitative exploration of proteins within and across species. Additionally, we developed MS2Bac, a bacterial identification algorithm that queries NCBI's bacterial proteome space in two iterations. MS2Bac achieved over 99% species-level and 89% strain-level accuracy, surpassing methods like MALDI-TOF and FTIR, as demonstrated with food-derived bacterial isolates. MS2Bac also effectively identified bacteria in clinical samples, highlighting the potential of MS-based proteomics as a routine diagnostic tool.

Emerging threats: Antimicrobial resistance in extended-spectrum beta-lactamase and carbapenem-resistant Escherichia coli

Antimicrobial resistance (AMR) in Escherichia coli strains, particularly those producing Extended-Spectrum Beta-Lactamase (ESBL) and Carbapenemase (CR-Ec), represents a serious global health threat. These resistant strains have been associated with increased morbidity, mortality, and healthcare costs, as they limit the effectiveness of standard antibiotic therapies. The prevalence of ESBL- and CR-Ec-producing strains continues to rise, driven by the overuse and misuse of antibiotics in healthcare and agricultural settings, and facilitated by global interconnectedness through international travel, trade, and food distribution. This review article examines the molecular mechanisms behind ESBL and CR resistance, focusing on the key genes involved in these processes, such as blaCTX-M, blaKPC, and blaNDM, and the clinical challenges posed by these strains. Additionally, the public health impact, including the spread of infections in hospital and community environments, is highlighted. The discussion emphasizes the urgent need for improved diagnostic tools, robust surveillance systems, and innovative therapeutic strategies. Emerging treatments, including phage therapy and novel antibiotic combinations, show promise in addressing these challenges and offer potential breakthroughs in combating resistant strains. Lastly, the review calls for stronger antimicrobial stewardship and policy reforms to mitigate the spread of resistant E. coli strains and protect global public health. Effective intervention at multiple levels, from diagnostics to policy, is critical to controlling the threat posed by AMR.

Monitoring Antibiotic Resistance in Wastewater: Findings from Three Treatment Plants in Sicily, Italy

Antimicrobial resistance (AMR) poses a global public health threat. Wastewater analysis provides valuable insights into antimicrobial resistance genes (ARGs), identifying sources and trends and evaluating AMR control measures. Between February 2022 and March 2023, pre-treatment urban wastewater samples were collected weekly from treatment plants in Pantano D'Arci, Siracusa, and Giarre (Sicily, Italy). Monthly composite DNA extracts were prepared by combining weekly subsamples from each site, yielding 42 composite samples-14 from each treatment plant. Real-time PCR analysis targeted specific ARGs, including blaSHV, erm(A), erm(B), blaOXA, blaNDM, blaVIM, blaTEM, and blaCTX-M. The preliminary findings revealed that blaERM-B, blaOXA, blaTEM, and blaCTX-M were present in all samples, with erm(B) (median value: 8.51; range: 1.67-30.93), blaSHV (0.78; 0.00-6.36), and blaTEM (0.72; 0.34-4.30) showing the highest relative abundance. These results underscore the importance of integrating ARG data with broader research to understand the persistence and proliferation mechanisms of ARGs in wastewater environments. Future studies should employ metagenomic analyses to profile resistomes in urban, hospital, agricultural, and farm wastewater. Comparing these profiles will help identify contamination pathways and inform the development of targeted ARG surveillance programs. Monitoring shifts in ARG abundance could signal cross-sectoral contamination, enabling more effective AMR control strategies.

Clinical presentation and antibiotic resistance trends of Escherichia coli isolated from clinical samples in South India: A two-year study (2022-2023)

BACKGROUND

Escherichia coli (E. coli) is a common pathogen responsible for various infections, particularly in healthcare settings. Its antibiotic resistance and susceptibility patterns are crucial for effective treatment. This study aims to assess the prevalence of E. coli in clinical samples and evaluate its antibiotic resistance patterns at SRM Medical Hospital and Research Center from 2022 to 2023.

METHODS

A retrospective study was conducted using microbiological records from 30,838 clinical samples collected over two years. Positive E. coli isolates were identified and subjected to antimicrobial susceptibility testing. Demographic data, including age and sex, were analysed. Resistance patterns were assessed using the Vitek 2 system and disc diffusion methods as per CLSI guidelines.

RESULTS

Out of 30,838 samples, 8694 yielded positive cultures, with 2597 E. coli isolates. Most isolates (69.6 %) were from urine, followed by exudate (20.4 %) and blood (6.8 %). E. coli infection was more prevalent in females (60.92 %) and individuals aged 41-70 years (48.97 %) (p < 0.001). High resistance was observed for amoxicillin-clavulanate (32 %) and ciprofloxacin (17.98 %), with high susceptibility to colistin (90.98 %) and piperacillin-tazobactam (90 %).

CONCLUSION

This study highlights the prevalence of E. coli, especially in urine samples and among females and older adults. High resistance to commonly used antibiotics emphasizes the need for regular susceptibility testing and antimicrobial stewardship.

CLINICAL IMPLICATION

This study emphasizes the need for ongoing antibiotic resistance monitoring and customized treatment strategies to combat E. coli infections. Future efforts should focus on enhancing antimicrobial stewardship programs to reduce the spread of resistant strains.

Investigation of methicillin, beta lactam, carbapenem, and multidrug resistant bacteria from blood cultures of septicemia suspected patients in Northwest Ethiopia

The presence of microorganisms in the bloodstream can result in severe, potentially life-threatening conditions, which are a significant cause of morbidity and mortality worldwide. The rise of antimicrobial-resistant strains further exacerbates these outcomes. However, the data concerning bacterial profiles and resistance to antimicrobials, particularly against extended-spectrum beta-lactams and carbapenems, are limited. Aimed to characterize pathogens isolated from positive blood cultures, including bacterial profiles and antibiotic susceptibility patterns, and to identify predictors of blood culture positivity in septicemia-suspected patients at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia. A hospital-based cross-sectional study was conducted from February 15 to May 30, 2023. The study involved 341 patients suspected of having septicaemia who were selected consecutively through a convenience sampling technique. Blood samples were collected aseptically from each patient (10 ml from adults, 5 ml from children, and 1 ml from neonates) and inoculated into bottles containing tryptic soy broth in volumes appropriate for the patient's age. The samples were incubated at 35-37 °C for up to 7 days to detect bacterial growth. Positive blood cultures were subcultured onto various media, including chocolate agar, blood agar, modified Thayer-Martin agar, MacConkey agar, and mannitol salt agar, and incubated again at 35-37 °C for 24 h. The suspected bacteria were identified on the basis of colony morphology, Gram staining, and biochemical tests. Antimicrobial susceptibility testing was conducted via both the Kirby-Bauer and modified Kirby-Bauer disk diffusion methods. Resistance to methicillin, extended-spectrum beta-lactams, and carbapenems was determined via the cefoxitin disc test, combined-disk diffusion method, and modified carbapenem inactivation method, respectively. The data were entered into Epi-Data version 4.6 and analysed via SPSS version 25. Binary logistic regression analyses were employed to identify factors associated with bloodstream infections (BSI), with a P value of less than 0.05 considered statistically significant. Out of 341 patients suspected of septicemia, 196 (57.5%) were male and 145 (42.5%) were female, with a mean (± SD) age of 16.5 (± 7.5) years. Bloodstream infection was identified in 87 (25.5%) patients (95% CI: 21.1-30.4). Among these positive cases, 67 (77%) were from ward patients, while 20 (23%) were from those visiting outpatient departments. The primary gram-positive bacteria identified included S. aureus 27 (31.0%), CoNS 14 (16.1%), S. viridans 8 (9.2%), and S. agalactiae 4 (4.6%). The gram-negative isolates were predominantly K. pneumoniae 11 (12.6%), followed by E. coli 9 (10.3%), E. cloacae 6 (6.9%), Acinetobacter spp. 3 (3.5%), N. meningitidis 3 (3.5%), and P. aeruginosa 2 (2.3%). Methicillin resistance was detected in 17/27 (63.0%) S. aureus strains and 2/14 (14.3%) CoNS strains. Multidrug resistance was detected in 63/87 (72.4%, 95% CI: 67.2-84.7%) of the isolates. Extended-spectrum beta-lactamase and carbapenemase production were observed in 12/31 (38.7%) and 5/31 (16.1%) of isolates, respectively. The factors associated with BSI were the presence of wounds and burns (AOR = 2.103, 95% CI: 1.365-3.241, P = 0.041), length of hospital stay (≥ 5) (AOR = 2.209, 95% CI: 1.122-4.347, P = 0.022), and prior medical procedures (AOR = 1.982, 95% CI: 1.125-3.492, P = 0.018). Bloodstream infection was identified in 25.5% of suspected septicemia cases, with multidrug-resistant bacteria present in 72.4% of isolates. Gram-positive bacteria, particularly S. aureus, and gram-negative bacteria like K. pneumoniae and E. coli were predominant. High rates of methicillin, beta-lactam, and carbapenem resistance were observed, emphasizing the magnitude of antimicrobial resistance. Risk factors such as wounds, extended hospital stays, and prior medical procedures significantly increased the likelihood of culture positivity. This suggests the need for regular antimicrobial susceptibility testing to guide antibiotic selection and track resistance trends, proper wound care and medical device usage to reduce the risk of BSI in healthcare settings.

Fe3O4@SiO2/Schiff-base/Zn (II) nanocomposite functioning as a versatile antimicrobial agent against bacterial and fungal pathogens

Antimicrobial resistance (AMR) presents a critical global health issue, necessitating novel therapeutic strategies to manage bacterial and fungal infections. This study explores the development and evaluation of multifunctional Fe3O₄@SiO₂/Schiff-base/Zn (II) magnetic nanocomposite (MNC) with enhanced antimicrobial properties. The synthesized MNC combines the magnetic characteristics of Fe₃O₄ magnetic nanoparticles (MNPs) with the antimicrobial properties of Schiff-base ligand functionalized with Zn (II) ions. The preparation involved the coprecipitation of Fe₃O₄, coating with SiO₂ via a modified Stöber method, and subsequent functionalization with Schiff-base/Zn (II) complex. Comprehensive characterization using FT-IR, XRD, SEM, TEM, DLS, EDX, VSM, and TGA confirmed successful synthesis, structural integrity, and superparamagnetic behavior of the MNPs and MNC. The antifungal and antibacterial activities were assessed against six Candida species and four bacterial strains using broth microdilution methods. The Fe₃O₄@SiO₂/Schiff-base/Zn (II) MNC exhibited significant inhibitory effects, with MIC values of 8-64 µg/mL for Candida species and 64-512 µg/mL for bacteria, demonstrating potent antimicrobial efficacy. The MTT assay indicated biocompatibility across various concentrations, except for slight cytotoxicity at 256 µg/mL after five days. To our knowledge, this is the first report integrating Zn (II) Schiff-base ligands into magnetic nanoparticles to achieve a versatile platform for both antimicrobial and biofilm inhibition applications.

Oral colonization of antimicrobial-resistant bacteria in home health care participants and their association with oral and systemic status

Antimicrobial-resistant bacteria (ARBs) are serious global threat because they make it difficult to treat infections with antibiotics. Recently, it has been demonstrated that ARBs are isolated from the oral cavities of elderly individuals in long-term care facilities. Because oral ARBs can cause systemic diseases such as bacteraemia and aspiration pneumonia, more attention must be given to protect the overall health of elderly people. To understand the prevalence of oral ARBs, more studies are needed in addition to previous studies. In this study, we investigated oral ARBs in elderly people receiving home health care (HHC) who had different lifestyles as residents in long-term care facilities. Among 98 HHC participants, Staphylococcus aureus, including 8 methicillin-resistant S. aureus (MRSA) strains, was isolated from 31 participants (31.7%), and 3rd-generation cephalosporin-resistant gram-negative bacteria (GNARB) were isolated from 18 participants (17.8%). An analysis of the relationship between oral ARBs and clinical status revealed that S. aureus/MRSA isolation was correlated with denture condition, while GNARB isolation was correlated with tube feeding. This study is the first comprehensive analysis of ARB carriage in the oral cavities of elderly people in HHCs. These results demonstrate the potential risk of oral ARB carriage and the importance of infection control in HHCs.

Phenotypic and Molecular Characterization of Extended-Spectrum β-Lactamase, Plasmid-Mediated- AmpC, and Carbapenemase-Producing Enterobacteriaceae Isolated from Companion and Production Animals in Brazil

The crisis of bacterial resistance is an emerging One Health challenge, driven by the overuse of antimicrobials in medical and agricultural settings. This study aimed to investigate extended-spectrum β-lactamase (ESBL), Ampicillinase (AmpC), and carbapenemase production, and the presence of genes encoding these enzymes in Escherichia coli, Klebsiella spp., and Proteus spp., major contributors to infections and resistance isolates from animals. From 2016 to 2021, 130 multidrug-resistant (MDR) or extensively drug-resistant (XDR) isolates were recovered from the secretions, excretions, and organs of companion and production animals with active infections. Antibacterial sensitivity tests, along with phenotypic and genotypic detection of resistance enzymes, were performed. To the best of our knowledge, this is the first study in Brazil to estimate the prevalence of XDR Enterobacteriales isolated from companion and production animals, which accounted for 13.8% of the strains. Statistically significant differences (P < 0.05) in resistant bacteria between different classes and within the same class of antibacterial bacteria were found. The statistical probability between genotypic detection of ESBL (OR = 3.1) and phenotypic tests for AmpC (OR = 2.3) was also established. Approximately 32.3%, 17.6%, and 16.8% of the strains had positive phenotypic tests for ESBL, AmpC, and carbapenemases, respectively. Genetic analysis revealed the presence of blaCTX-M (60.0%), blaAmpC (9.18%), blaKPC-2 (0.76%), and blaNDM (1.52%). AmpC genes were identified in 8.46% of the samples, with blaCMY being the most frequent (6.92%), followed by blaDHA (0.77%), and blaFOX (0.77%). The sequenced amplicons were deposited in NCBI. This study reveals critical data on Enterobacteriaceae with antibacterial resistance genes isolated from animals and may pose a significant threat to One health.

Anti-Inflammatory and Antimicrobial Effects of Herbal Formulation Called Apo-Taat Using Extended-Spectrum ß-Lactamase-Producing Escherichia coli Isolates

Pathogens contaminate drinking water in tropical countries causing diarrheal diseases. The conventional treatment for diarrhea is antibiotics. However, overuse and misuse of antibiotics has enabled pathogens to adapt, causing global antibiotic resistance and proliferation of extended-spectrum ß-lactamase-producing Escherichia coli (ESBL-E. coli), which causes diarrhea and high levels of inflammatory cytokines. Apo-taat, consisting of equal proportions of Phyllanthus emblica and Caesalpinia sappan, has been used to treat diarrhea and bloody diarrhea. Its antibacterial activity against E. coli ATCC 25922 has been reported, but its inhibitory effect against ESBL-E. coli has yet to be documented. This study investigated the antibacterial effect of Apo-taat extract against ESBL-E. coli and its anti-inflammatory activity. Antibacterial activity was determined by the microtiter plate-based method. HPLC was used to determine the brazilin and gallic acid contents in Apo-taat extract. Effects of herbal extracts on nitric oxide, IL-6, and TNF-α were investigated in RAW 264.7 cells. Results were that Apo-taat extract showed MIC values against ESBL-E. coli in the range of 0.625 to 2.5 mg/mL. Its 50% inhibitory concentration against nitric oxide and IL-6 production was 83.96 ± 10.60 and 83.06 ± 2.07 μg/mL, respectively, and it had slight inhibition against TNF-α. These findings suggest that Apo-taat may have an antibacterial impact on ESBL-E. coli and anti-inflammatory activity. Furthermore, safety and clinical trials should be conducted in the future.

Preserving the antimicrobial arsenal: exploring alternatives to carbapenems in ESBL battles within the southeast of Ireland

Introduction. Carbapenems are usually employed as first-line antimicrobials against bacteria harbouring extended-spectrum beta-lactamases (ESBLs). These enzymes confer resistance often to multiple classes of antimicrobials.Hypothesis/Gap Statement. This indiscriminate use of carbapenems and the inevitable development of carbapenem resistance have prompted the need for carbapenem-sparing strategies.Methodology. The non-carbapenem antimicrobial susceptibility patterns of 60 ESBL-producing Enterobacterales (ESBL-PE) isolates responsible for bloodstream infections, in 2022-2023 inclusive, processed at our institution were reviewed.Results. The non-carbapenem antimicrobial susceptibility patterns of 60 ESBL-PE isolates from bloodstream infections during the study period were determined. Escherichia coli was the most common species isolated (87%, n=52), with the majority of cases (73.3%, n=44) originating from a presumed urinary source. Temocillin (TMC), mecillinam (MEC), cefiderocol (FDC), amikacin and fosfomycin (FOS) displayed excellent activity against all ESBL-PE isolates tested, with susceptibility rates of≥85%. Ciprofloxacin and amoxicillin-clavulanic acid were the least efficacious agents, with susceptibility rates≤20%.Conclusions. TMC, MEC, FDC and FOS offer promising alternatives to carbapenems, demonstrating efficacy against ESBL-PE. The use of these agents not only broadens the therapeutic arsenal against ESBL-PE but also mitigates the potential for escalating carbapenem resistance, especially in regions where the incidence of carbapenem resistance is increasing.

The continued evolution of the L2 cephalosporinase in Stenotrophomonas maltophilia: a key driver of beta-lactam resistance

The Stenotrophomonas maltophilia L2 cephalosporinase is one of two beta-lactamases that afford S. maltophilia beta-lactam resistance. With the overuse of beta-lactams, selective pressures have contributed to the evolution of these proteins, generating proteins with an extended spectrum of activity. Variant L2 cephalosporinases have been detected, as has their distribution into two main clades (clades 1 and 2). Comprehensive analysis of six L2 variants, cloned into pET41a(+) and expressed in Escherichia coli BL21(DE3) cells, revealed that clade 1 variants exhibited higher ceftazidime resistance compared to clade 2. Notably, the Sm5341 L2 variant, carrying a Phe72Ile variation, displayed a significantly reduced resistance profile across all substrates tested, suggesting a key role of Phe72 in enzymatic activity. An Ile72Phe substitution in the pET41a(+) based Sm5341_L2 variant resulted in a gain-of-function for this protein, confirming the role of Phe72 in the activity of L2. Furthermore, residue interaction network analysis elucidated a pi-cation interaction between Tyr272 and Arg244, which may potentially be stabilizing the enzyme and its binding site. The presence of Tyr272 in clade 1 variants correlates with higher ceftazidime affinity, contrasting Asp272 in clade 2 variants. Displaying lower Km values and higher kcat/Km ratios, clade 1 L2 enzymes demonstrated a higher binding efficiency and greater catalytic efficiency for most of the substrates assessed. These results indicate that L2 enzymes are continuing to evolve and adapt to a selective environment fuelled by the overuse of beta-lactams. This adaptation may signal the beginning of an evolutionary process yielding variant L2 cephalosporinases with extended substrate profiles.

A randomised non-inferiority trial investigating antibiotic adjustments based on blood culture in acute cholangitis

OBJECTIVES

This study evaluated the adequacy of using blood cultures alone for antibiotic therapy in mild-to-moderate acute cholangitis after adequate biliary drainage.

METHODS

A prospective, multi-centre, non-inferiority, randomised trial was conducted from August 2015 to September 2023 across 12 tertiary hospitals in South Korea. Patients were randomly assigned 1:1 to groups. The control group was administered antibiotics based on blood and bile culture results, whereas the experimental group treated based on blood culture results alone. The primary outcome was the rate of organ failure, assessed by the presence of shock, acute kidney injury, altered mental status, and acute respiratory distress. The secondary outcomes were all-cause mortality, frequency of re-interventions, antibiotic usage duration and hospital stay. The non-inferiority margin was 10%.

RESULTS

Patients in the control group (n = 215) and experimental group (n = 213) were analyzed. Organ failure occurred in 28 (13.0%) in the control and 27 (12.7%) in the experimental group (Difference: -0.350% [95% confidence interval, -6.690 to 5.990], p > 0.999). Mortality rates were 3.3% in the control (7 patients) and 2.3% in the experimental group (5 patients) (-0.908% [-4.033 to 2.216], p = 0.782). The re-intervention rates were 31 (14.9%) in the control and 26 (12.2%) in the experimental groups (-2.677% [-9.155 to 3.801], p = 0.504). The antibiotic therapy duration was different (-1.500 days [-2.840 to -0.160], p = 0.037) between the control (12.8 ± 8.0 days) and the experimental groups (11.3 ± 6.5 days), and the hospital stay was different (-1.900 days [-0.380 to 0.000], p = 0.046) between the control (14.1 ± 11.0 days) and the experimental group (12.2 ± 9.0 days).

CONCLUSIONS

This study confirms that relying on blood culture results alone for managing mild-to-moderate cholangitis is reasonable and may help reduce the unnecessary use of medical resources.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT02601417).

Case Report: Management of a case of multidrug-resistant Klebsiella pneumoniae infection in a second-kidney transplant patient

This case report on recurrent urinary tract infections (UTIs) caused by multidrug-resistant (MDR) Klebsiella pneumoniae in a post-renal transplant patient underscores the significant clinical challenge of managing MDR infections in immunocompromised individuals, particularly in the context of renal transplantation. The patient was treated with an extended infusion of meropenem, which offers prolonged drug exposure and enhances bactericidal activity against MDR pathogens. This approach is critical in overcoming the resistance mechanisms inherent to Klebsiella pneumoniae, thereby improving the likelihood of therapeutic success. The findings presented here highlight the potential efficacy of extended meropenem infusion in treating MDR infections, providing a valuable therapeutic option for clinicians facing similar cases. This report contributes to the growing evidence supporting advanced antibiotic administration techniques in managing complicated urinary tract infections in transplant in resource limited countries.

Editorial for Special Issue "Antibiotic Combination Therapy: A Strategy to Overcome Bacterial Resistance"

Multidrug-resistant (MDR) bacterial infections have emerged as a critical global health threat, challenging the efficacy of existing antibiotics and undermining advances in modern medicine [...].

Extended-spectrum β-lactamase production and antimicrobial resistance among Enterobacteriaceae causing clinical infections in Africa: a systematic review and meta-analysis (2012-2020)

BACKGROUND

Worldwide, antimicrobial resistance (AMR) has grown to represent a serious threat to the diagnosis, management, and prevention of bacterial diseases. Due to their multidrug resistance attributes, the WHO has classified extended-spectrum-β-lactamase-producing Enterobacteriaceae (ESBL-PE)-associated infections as infections of critical significance, posing a serious risk to human health. Thus, the goal of this systematic review and meta-analysis was to assess the pooled prevalence of ESBL-PE and AMR among strains causing clinical infections in Africa.

METHODS

In this systematic review and meta-analysis, two investigators independently made an electronic search in Google Scholar and PubMed databases using related keywords and corresponding "MeSH." terms for the PubMed. The accessed studies were screened, assessed for eligibility, and critically evaluated as per the PRISMA guidelines. The prevalence and 95% confidence intervals (CI) for ESBL-PE in Africa were evaluated using a random-effects model of a meta-analysis. As a visual and statistical way assessment, the funnel plot and Egger's test were utilized to assess the risk of bias or publication bias, with a statistically significant level of bias being determined at p < 0.05.

RESULTS

Twenty-six studies were included in the meta-analysis. Among the included studies done in Africa, the overall pooled proportion of ESBL-PE was reported to be 28% (95% CI 25-31%). ESBL-PE prevalence differed by region, the pooled estimates for East and North Africa were 29% (95% CI 20-38%) and 19% (95% CI 6-33%), respectively. The greatest sub-group analysis of pooled estimates among bacterial isolates was found in Klebsiella. pneumoniae, at 73% (95% CI 62-85%), while Proteus mirabilis had the lowest, at 40% (95% CI 1-81%).

CONCLUSIONS

In Africa, ESBL-PE is noticeably prevalent. The included studies demonstrated a significant variation in ESBL-PE resistance among the countries. This illustrates the necessity of actively monitoring antimicrobial resistance in Africa to develop interventions aimed at halting the spread of ESBL-PE.

Aetiological, seasonal and antibiotic susceptibility patterns of diarrhoeal diseases in Bhutan (2016-2022): a retrospective study of surveillance data

OBJECTIVES

This study aimed to identify the aetiological spectrum, seasonal distribution and antimicrobial resistance patterns of diarrhoeal diseases in Bhutan.

STUDY DESIGN AND SETTING

The study used a cross-sectional, retrospective analysis of secondary data gathered through a passive, hospital-based sentinel surveillance for diarrhoeal disease across 12 hospitals, representing Bhutan's demographically diverse regions.

PARTICIPANTS

A total of 3429 participants' data of all age groups who presented with diarrhoea at sentinel hospitals between 1 January 1 2016 and 31 December 2022 were analysed.

RESULTS

Diarrhoeagenic Escherichia coli (DEC), Shigella, Salmonella and Aeromonas spp. were predominant bacterial pathogens, while Rotavirus, Astrovirus and Norovirus were the leading viral pathogens. Coinfections were observed in 195 cases. Children under nine were significantly affected than the other age groups. Seasonal trends revealed that bacterial pathogen incidence peaked during the summer/monsoon season, viral pathogens were more common in winter and spring, and parasites persisted year-round. Among the antibiotics tested, gentamicin, chloramphenicol, ceftriaxone and tetracycline exhibited high efficacy, with susceptibility rates of 93.4%, 87.2%, 81.5% and 69.5%, respectively. Conversely, high resistance rates were observed for amoxicillin (80.3%), ampicillin (77.4%) and nalidixic acid (69.5%). Multidrug resistance was prevalent, with β-lactamase production contributing to resistance rates of 80.7% to penicillin and 65.4% to fluoroquinolones groups. Cephalosporin resistance was also notable, with rates of 34.4% for cephalexin, 40.0% for cefazolin and 16.9% for ceftriaxone.

CONCLUSIONS

DEC and Rotavirus were identified as the leading causes of diarrhoea, with significant resistance patterns observed in common bacterial isolates. These findings underscore the need for DEC screening in paediatric cases and emphasise the need for sustained antimicrobial resistance surveillance.

Multidrug-Resistant Acinetobacter baumannii: Risk Factors for Mortality in a Tertiary Care Teaching Hospital

BACKGROUND AND OBJECTIVES

Due to resistance and the lack of treatment options, hospital-acquired Acinetobacter baumannii (A. baumannii) infections are associated with high mortality. This study aimed to analyze the characteristics of patients with infections caused by multidrug-resistant (MDR) A. baumannii and patients' clinical outcomes as well as determine the risk factors for mortality in a tertiary care teaching hospital.

MATERIALS AND METHODS

A retrospective cohort study including 196 adult patients with A. baumannii strains isolated from different clinical specimens in the Hospital of the Lithuanian University of Health Sciences in 2016, 2017, 2020, and 2021 was conducted. Data on patients' characteristics, comorbid diseases, treatment, length of hospital and ICU stay, and outcome were collected. Carbapenemase-producing isolates were detected phenotypically. To determine risk factors for in-hospital mortality, logistic regression analysis was performed.

RESULTS

There were 60 (30.6%) women and 136 (69.4%) men with a mean age of 61.7 ± 16.6 years (range, 52-74). More than three-fourths (76.5%, n = 150) of the patients had at least one comorbid disease. The highest number of A. baumannii strains were isolated from patients hospitalized in ICUs (43.4%, n = 85). A. baumannii strains producing three types of β-lactamases were more frequently isolated from women than men (77.8% vs. 22.2%, p = 0.006). Infections caused by A. baumannii strains producing two types of β-lactamases were significantly more often treated with combination therapy than infections caused by strains producing one type of β-lactamase (78.9% vs. 60.0%, p = 0.019). Patients with A. baumannii strains producing two different types of β-lactamases (AmpC plus KPC, AmpC plus ESBL, or ESBL plus KPC) stayed significantly shorter at the ICU compared to patients with A. baumannii strains with no detected β-lactamases (median of 9, IQR 2-18, vs. median of 26, IQR 7-38, p = 0.022). Death occurred in 58.7% (n = 115) of patients. Logistic regression analysis showed that a duration of the effective antibiotic treatment of ≤6 days, invasive mechanical ventilation, combination therapy, aged >58 years, and the absence of co-infection were independent predictors of in-hospital mortality.

CONCLUSIONS

MDR A. baumannii infections pose a significant threat to human health not only due to multidrug resistance but also due to high mortality. The mortality rate of patients with MDR A. baumannii infection was high and was associated with age, invasive mechanical ventilation, the duration of effective antibiotic treatment, no co-infection, and combination therapy. Therefore, it is of utmost importance to reduce the prevalence of MDR A. baumannii infections in healthcare facilities by applying preventive measures and to administer timely effective treatment once A. baumannii infection is detected.

Molecular detection of blaTEM-encoding genes in multidrug-resistant Escherichia coli from cloacal swabs of ducks in Indonesia farms

Background

Globally, there is an increasing frequency of community-acquired illnesses caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. The presence of ESBL-producing E. coli in livestock is a concern, considering its transmission potential to humans, effects on animal health, risks to food safety, and the widespread spread of antibiotic resistance in both human and animal populations.

Aim

This study investigated the prevalence and characterization of ESBL-producing E. coli in cloacal swab samples collected from duck farms in Jombang, Indonesia.

Methods

In total, 125 cloacal swab samples of ducks were collected from farms. Samples were processed and analyzed for E. coli isolation using standard microbiology techniques. Isolated E. coli strains were further subjected to antimicrobial susceptibility testing and ESBL phenotypic detection using disc diffusion and double-disk synergy test techniques, respectively. Identified multidrug-resistant (MDR) E. coli strains were thereafter screened for the detection of blaTEM ESBL gene by PCR.

Results

A total of 94 (52.2%) out of the collected 180 swab samples were positive for E. coli. Twenty-five (39.1%) out of the recovered E. coli isolates were generally noted to exhibit MDR traits. Exactly 24 (96%) out of the 25 MDR E. coli strains that were selected for molecular studies harbored the blaTEM gene.

Conclusion

The detection of MDR E. coli harboring blaTEM ESBL gene in ducks in our study area is a significant public health problem. Therefore, strong and impactful preventive measures, which would curtail the increasing dissemination of MDR bacterial pathogens in agricultural settings, are urgently needed.

Genetic diversity and antibiotic resistance patterns of Escherichia coli isolates causing septicemia: A phylogenetic typing and PFGE analysis

INTRODUCTION

This study aims to analyze clinical isolates of E. coli causing septicemia across various phylogroups utilizing the PFGE method.

MATERIALS AND METHODS

A total of 100 clinical isolates were collected. The presence of CTX-M, TEM, SHV, KPC, MBL and OXA-48 genes was detected by PCR. Additionally, phylotyping, serotyping, and virulence-typing assay were done by PCR and PFGE methods to investigate the genetic diversity of the isolates.

RESULTS

The O1 serotype and the HlyA gene were the most prevalent serotype and virulence gene, respectively. Notably, 34% of the isolates harbored SHV, TEM, and CTX-M-1 β-lactamase genes. All isolates showed resistance to amoxicillin and tetracycline, but no resistance to fosfomycin was seen. The most and least common phylotypes, according to PFGE analysis, belonged to phylogroups B2 and B1, respectively.

CONCLUSION

The data offers valuable insights into the genetic diversity and antibiotic resistance patterns of E. coli isolates responsible for septicemia.

Molecular detection of blaTEM-encoding genes in multidrug-resistant Escherichia coli from cloacal swabs of ducks in Indonesia farms

Background

Globally, there is an increasing frequency of community-acquired illnesses caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. The presence of ESBL-producing E. coli in livestock is a concern, considering its transmission potential to humans, effects on animal health, risks to food safety, and the widespread spread of antibiotic resistance in both human and animal populations.

Aim

This study investigated the prevalence and characterization of ESBL-producing E. coli in cloacal swab samples collected from duck farms in Jombang, Indonesia.

Methods

In total, 125 cloacal swab samples of ducks were collected from farms. Samples were processed and analyzed for E. coli isolation using standard microbiology techniques. Isolated E. coli strains were further subjected to antimicrobial susceptibility testing and ESBL phenotypic detection using disc diffusion and double-disk synergy test techniques, respectively. Identified multidrug-resistant (MDR) E. coli strains were thereafter screened for the detection of blaTEM ESBL gene by PCR.

Results

A total of 94 (52.2%) out of the collected 180 swab samples were positive for E. coli. Twenty-five (39.1%) out of the recovered E. coli isolates were generally noted to exhibit MDR traits. Exactly 24 (96%) out of the 25 MDR E. coli strains that were selected for molecular studies harbored the blaTEM gene.

Conclusion

The detection of MDR E. coli harboring blaTEM ESBL gene in ducks in our study area is a significant public health problem. Therefore, strong and impactful preventive measures, which would curtail the increasing dissemination of MDR bacterial pathogens in agricultural settings, are urgently needed.

Detection of blaTEM, blaOXA, blaCTX-M, and blaSHV genes of antibiotic resistance in diarrheagenic E. coli causing enteric infection in hypertensive patients at Laquintinie Hospital, Littoral Region of Cameroon

BACKGROUND

Pathogenic Escherichia coli is one of the most common causes of acute watery diarrhea among children and adults in the developing world. The severity of infection by this bacterium is a product of many factors, including virulence properties and antimicrobial resistance. This study aimed to determine the distribution of different virulence genes of E. coli isolates in hypertensive and non-hypertensive patients and their association with some selected beta-lactam resistance genes.

METHODS

At the Douala Laquintinie Hospital, 518 fecal samples were collected from both hypertensive and non-hypertensive patients with enteric infections. E. coli was isolated on eosin-methylene blue agar (EMB) and identified by the Api 20 E Galery. The virulence genes and extended-spectrum β-lactamase-producing (ESBL) E. coli genes were detected by simplex polymerase chain reaction (PCR), while antimicrobial susceptibility was tested by the Kirby-Bauer agar disc diffusion method.

RESULTS

The prevalence of enteric infection due to diarrheagenic E. coli (n = 204) was found to be 39.38 % in the general population (n = 518). There were 55 enterovirulent E. coli isolates identified. According to hypertension (HTN), enteropathogenic E. coli (EPEC) isolates were more isolated in hypertensive patients (77.78 %) than in non-hypertensive patients (22.22 %), while enteroaggregative E. coli (EAEC) were the most frequent in non-hypertensive patients (58.33 %). EPEC, EAEC, enterotoxigenic E. coli (ETEC), and Shiga toxin-producing E. coli (STEC) isolates showed higher rates of resistance to amoxicillin (AMO) (90.48 %; 100.00 %; 100.00 %; 100.00 % vs 83.33 %; 85.71 %; 75.00 %; 50.00 %) and SXT (71.43 %; 80.00 %; 75.00 %; 75.00 % vs 0.00 %; 28.57 %; 50.00 %; 25.00 %) in hypertensive patients compared to non-hypertensive patients. The prevalence of ESBL-producing (ESBL-P) E. coli was 87.27 %. The resistance genes blaTEM (64.71 % vs 52.38 %) and blaOXA (23.53 % vs 9.52 %) were more frequently detected in hypertensive patients than in non-hypertensive patients. The high resistance to AMO was correlated with the presence of the blaCTX-M gene (OR: 5.52; 95 % CI: 0.61-49.39; p = 0.093).

CONCLUSION

This study reveals the high burden of the typical EPEC, EAEC, and ESBL-P E. coli and confirmed the high occurrence of blaCTX-M and blaTEM among ESBL-producing E. coli in hypertensive patients. The study suggests that measures need to be taken to reduce the harmfulness of enterovirulent E. coli and the resistance of enterovirulent E. coli in hypertensive patients.

Molecular Analysis of Escherichia coli and Correlations Between Phylogroups and Sequence Types from Different Sources

Escherichia coli is a significant pathogen responsible for infections in both humans and livestock, possessing various virulence mechanisms and antimicrobial resistance that make it even more concerning. In this study, several internationally recognized clones of E. coli were identified, such as ST131, ST38, ST648, and ST354, from chicken meat, pork, and human infection samples. Notably, ST131, belonging to phylogroup B2, was the dominant sequence type (ST) in human samples, while ST38, belonging to phylogroup D, was the most prevalent in meat samples. Several antibiotic resistance genes were identified: the gyrA gene mutation was the most prevalent, and CTX-M-55 was the most common extended-spectrum beta-lactamases (ESBLs), with significant differences noted for CTX-M-2 and CTX-M-15. Virulence-associated genes (VAGs) such as gad and iss were frequently found, especially in human isolates. These findings highlight the complex epidemiology of antibiotic-resistant E. coli in community settings and the potential risks associated with commercial meat.

Differences in microorganism profile in periprosthetic joint infections of the hip in patients affected by chronic kidney disease

BACKGROUND

Patients affected by chronic kidney disease (CKD) are at increased risk of periprosthetic joint infection (PJI) after total hip arthroplasty (THA). This patient population has a higher risk of recurrent infections and hospitalization. The aim of this study is to compare the profile of microorganisms in patients with CKD and PJI of the hip versus controls and to individuate potentially unusual and drug-resistant microorganisms among the causative bacteria.

MATERIALS AND METHODS

A total of 4261 patients affected by PJI of the hip were retrospectively studied. Patients affected by CKD in this population were identified and compared with a control group of patients with PJI but without CKD. Data on patient characteristics and comorbidities were collected. The microorganisms responsible for PJI were identified and compared between both groups.

RESULTS

The CKD group included 409 patients, 54.3% male, mean age of 73.8 ± 8.9 years, a higher body mass index (BMI) than the general population (29.88 ± 5.90 kg/m2), and higher age-adjusted CCI of 6.15 ± 2.35. Overall, 70 different isolates of microorganisms were identified, including 52 Gram-positive spp., 28 Gram-negative spp., 3 fungi, and 1 mycobacterium. Polymicrobial infections were more common in CKD group than controls (47.9% versus 30.9%; p < 0.0001). Staphylococcus spp. were the most common bacteria in both groups, followed by Gram-negative Enterobacteriaceae and Streptococcus spp. CKD group showed a higher risk of developing infections caused by Staphylococcus aureus (p = 0.003), Gram-negative bacteria, and Candida (p = 0.035).

CONCLUSIONS

Renal failure exposes patients who undergo THA to PJI caused by microorganisms that are potentially more drug resistant, leading to a higher risk of treatment failure. Knowing in advance the different microorganism profiles could help to plan a different surgical strategy.

Insight into the Prevalence of Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Vegetables: A Systematic Review and Meta-Analysis

The occurrence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in vegetables is an escalating global problem. This study aimed to document the global prevalence of ESBL-producing Enterobacteriaceae in vegetables using a comprehensive meta-analysis. A web-based search of electronic databases such as ScienceDirect, Google Scholar, and PubMed was conducted using studies published between 2014 and 2024. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed for the systematic review and meta-analysis. The Comprehensive Meta-Analysis (CMA) Ver 4.0 software was used to analyse the data. The pooled prevalence estimate (PPE) with a 95% confidence interval (CI) was calculated using the random effects model. After reviewing 1802 articles, 63 studies were carefully analyzed and were part of the comprehensive meta-analysis. The overall PPE of ESBL-producing Enterobacteriaceae (ESBL-E) was 11.9% (95% CI: 0.091-0.155), with high heterogeneity (I2 = 96.8%, p < 0.001) from 2762 isolates. The blaSHV ESBL-encoding gene was the most prevalent, showing a PPE of 42.8% (95% CI: 0.269-0.603), while the PPE of blaampC-beta-lactamase-producing Enterobacteriaceae was 4.3% (95% CI: 0.025-0.71). Spain had a high ESBL-E PPE of 28.4% (0.284; 95% CI: 0.057-0.723, I2 = 98.2%), while China had the lowest PPE at 6.4% (0.064; 95% CI: 0.013-0.259, I2 = 95.6%). Continentally, the PPE of ESBL-E was significantly higher in reports from South America at 19.4% (95% CI: 0.043-0.560). This meta-analysis showed that ESBL-E in vegetables increased by 9.0%, 9.8%, and 15.9% in 2018-2019, 2020-2021, and 2022-2024, respectively. The findings emphasize the potential risks of consuming raw or inadequately cleaned produce and the importance of vegetables as ESBL-E reservoirs. Our work calls for immediate attention to food safety procedures and more thorough surveillance as antibiotic resistance rises to reduce antimicrobial resistance risks in food systems.

Prevalence and molecular characterization of ESBL-producing Enterobacteriaceae in Egypt: a systematic review and meta-analysis of hospital and community-acquired infections

BACKGROUND

ESBL-producing Enterobacteriaceae (ESBL-PE) represent a significant global health threat. In response to this growing concern and the lack of a surveillance system for ESBL-PE infections in Egypt, we conducted this meta-analysis. In this study, we aimed to quantify the prevalence of ESBL-PE based on the source of infection and characterize their molecular dissemination. Additionally, we sought to uncover temporal trends to assess the spread of ESBL-PE over time.

METHODS

A comprehensive literature search was conducted in PubMed, Scopus, Google Scholar, Web of Science, and the Egyptian Knowledge Bank to identify studies that: (1) report the prevalence of ESBL-PE in Egypt; (2) use valid detection methods; (3) involve clinical specimens; and (4) were published between 2010 and 2024. The quality of the included studies was evaluated using the "Joanna Briggs Institute Critical Appraisal Checklist". Meta-analysis was performed using the R meta package, reporting pooled prevalence with 95% confidence intervals (CI) via a random effects model.

RESULTS

This meta-analysis included 34 studies with 4,528 isolates, spanning 2007 to 2023. The overall prevalence of ESBL-PE in Egypt was 60% (95% CI: 54-65). The leave-one-out meta-analysis demonstrated the absence of influential outliers and Egger's test indicated no evidence of publication bias (P = 0.25). The prevalence of ESBL-PE was 62% (95% CI: 55-68) in nosocomial infections and 65% (95% CI: 52-75) in community-acquired infections, with no statistically significant difference (P = 0.68). The prevalence of ESBL producers in E. coli (64%) and K. pneumoniae (63%) is higher than in Proteus mirabilis (46%) (P = 0.06). Temporal analysis showed a stable ESBL prevalence over time. Moreover, in phenotypically confirmed ESBL-producing, E. coli harboring blaCTX-M was most prevalent (73%), followed by blaTEM (60%) and blaSHV (22%), with significant differences (P < 0.01). Subsequent analysis identified blaCTX-M-15 as the predominant variant of the blaCTX-M gene.

CONCLUSIONS

The prevalence of ESBL-PE in Egypt is alarmingly high at 60%. The observed high rates in both hospital and community-acquired infections underscore the need for public health strategies targeting both settings. One limitation of this study is the high heterogeneity, which partly attributed to regional and institutional variations in antibiotic use and stewardship practices.

Prevalence, Antimicrobial Susceptibility, and Resistance Genes of Extended-Spectrum β-Lactamase-Producing Escherichia coli from Broilers Sold in Open Markets of Dakar, Senegal

Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-Ec) poses a significant public health concern due to its widespread prevalence and resistance to multiple antibiotics. This study aimed to assess the prevalence, resistance profile, and carriage of ESBL-encoding genes in ESBL-Ec isolates from broilers in two markets of Dakar, Senegal. Sampling over a one-year period revealed that 61.7% of broilers carried ESBL-Ec in their cecum. Antibiotic susceptibility testing of 186 ESBL-Ec isolates showed high resistance to β-lactam antibiotics, including ampicillin, ticarcillin, and third-generation cephalosporins. Notably, all isolates were susceptible to imipenem. Multidrug resistance was frequent, with 91.4% of the isolates displaying this phenotype. Comparison between the two markets revealed variations in resistance to quinolones. PCR analysis detected blaCTX-M genes in all isolates, with blaCTX-M-1 being the most prevalent subgroup. Additionally, blaTEM and blaOXA genes were found in 26.3% and 2.7% of isolates, respectively, while no blaSHV genes were detected. Combinations of ESBL genes were common, with blaCTX-M15-blaTEM being the most frequent. These findings highlight the widespread prevalence of ESBL-Ec in broilers from Dakar markets, indicating a potential risk of transmission to humans through the food chain. Effective surveillance and intervention strategies are crucial to mitigate the spread of antimicrobial resistance in humans and animals.

Is It Time to Start Worrying? A Comprehensive Report on the Three-Year Prevalence of ESBL-Producing Bacteria and Their Trends in Antibiotic Resistance from the Largest University Hospital in Slovakia

BACKGROUND/OBJECTIVES

Over the past few decades, extended-spectrum β-lactamase (ESBL)-producing bacteria have become a great concern in healthcare systems worldwide, imposing large burdens by increasing antimicrobial resistance and patient morbidity. Given the high mortality rates and emergence of multidrug-resistant (MDR) strains, monitoring ESBL prevalence and resistance patterns is crucial. This study aimed to evaluate ESBL-producing Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae over three years, focusing on phenotypic distribution and resistance profiles.

METHODS

A total of 1599 ESBL-producing bacterial samples were collected and analysed. A panel of 20 antibiotics was tested to determine resistance traits. Data were recorded on phenotypical distribution, isolation types, changes in antibiotic resistance, and the relation of such changes to antibiotic consumption (defined daily dose) from clinical isolates.

RESULTS

Phenotypical analysis revealed the minimal presence of the Cefotaximase from Munich (CTX-M) phenotype in E. coli and K. pneumoniae, creating a distinct epidemiological profile compared to global patterns. Shifts in isolation trends, particularly in P. mirabilis, suggest an expected increase in associated-mortality-rate in the coming years. While resistance trends were not statistically significant, MDR and extensively drug-resistant (XDR) strains were identified across all three bacteria. Only meropenem showed consistent 100% efficacy against E. coli, with other antibiotics displaying only partial effectiveness.

CONCLUSIONS

These findings highlight the need for ongoing surveillance of ESBL-producing bacteria and underscore challenges in managing antibiotic resistance due to limited efficacy of last-resort treatments. The unique phenotypical distribution observed could impact local resistance management strategies in hospital settings in the coming years.

Faecal carriage of extended-spectrum beta-lactamase and carbapenemase-producing enterobacterales among HIV patients at Jimma Medical Center, Southwest Ethiopia

BACKGROUND

Enterobacterales infections in immunocompromised individuals are associated with considerable morbidity, mortality, and health care costs. This study aimed to assess the faecal carriage of extended-spectrum β-lactamase (ESBL) and carbapenemase-producing Enterobacterales (CPE) among HIV-infected patients at Jimma Medical Center. A total of 344 stool samples were collected and inoculated on Mac-Conkey and Eosin-Methylene Blue agar and incubated at 35-37 °C aerobically. ESBL and carbapenemase production were detected using D68C ESBL/AmpC and D73C CARBA plus (Mast Group, UK).

RESULTS

A total of 376 Enterobacterales were isolated. The prevalence of ESBL-PE and CPE carriage rate was 13.3% (50/376) and 4.3% (16/376) respectively. The highest proportion of ESBL producing isolates were found in K. pneumoniae 29.0% (9/31) followed by E. coli 13.4% (39/292). Similarly, K. pneumoniae 12.9% (4/31) was the most common carbapenem-resistant isolate followed by E. coli 3.8% (11/292). Multi-drug resistance was observed in 66.5% (250/376) of the isolates. Prior cephalosporin use (AOR = 7.9; 2.31-27.29), CD4 count (≤ 350 cells/µL) (AOR = 3.8; 1.12-12.9), and comorbidities (AOR = 2.3; 1.24-4.32) were significantly associated with ESBL production. Additionally, cephalosporin use (AOR = 6.34; 1.27-31.66) was significantly associated with the presence of CRE.

CONCLUSIONS

This study revealed a high prevalence of ESBL-PE and CPE among HIV patients, with K. pneumoniae and E. coli being the dominant isolates. MDR was common, with key risk factors being prior cephalosporin use, low CD4 counts, and comorbidities. These findings emphasize the need for enhanced infection prevention and control, regular screening, and improved antibiotic stewardship to curb the spread of resistant bacteria in immunocompromised individuals.

"Molecular Characterization of Extended Spectrum Beta-Lactamase Resistance in Pediatric Shigella Isolates in Egypt"

Shigellosis is a major cause of morbidity and mortality among children, especially in developing countries. The increased extended-spectrum beta-lactamase (ESBL) resistance in Shigella poses a challenge for effective treatment. To examine the antibiotic resistance and ESBL profile of Shigella isolates from children with acute diarrhea. Shigella was isolated from stool cultures from pediatric patients suffering from acute diarrhea. The isolates were identified by bacteriological tests, serotyping, and multiplex polymerase chain reaction (PCR). The antimicrobial resistance was examined by disc diffusion. Phenotypic tests and PCR examined the ESBLs and CTX-M, SHV, and TEM genes. A total of 100 Shigella (10% prevalence rate) were isolated. The S. sonnei and S. dysenteries were the most prevalent species (33% and 31%, respectively), followed by S. flexneri (27%), and only 9% were S. boydii. The isolates had complete resistance (100%) to ampicillin. There was lower resistance to ciprofloxacin (24%), and no resistance to imipenem. By phenotypic tests, 54% of isolates had ESBL. By PCR, bla-CTX-M gene was the most prevalent (50%), followed by bla-TEM (48.1%). Only one isolate (1.9%) had the bla-SHV gene. The alarmingly high rates of antibiotic resistance and ESBL resistance among Shigella spp highlight the urgent need to restrict the unguided use of these drugs. Continuous monitoring of local and global antibiotic resistance patterns is required to prevent the spread of resistance.

Genetic Insights on Meropenem Resistance Concerning Klebsiella pneumoniae Clinical Isolates

The transferable genetic elements are associated with the dissemination of virulence determinants amongst Klebsiella pneumoniae. Thus, we assessed the correlated antimicrobial resistance in carbapenem-resistant Klebsiella pneumoniae clinical isolates. Each isolate's ability to biosynthesize biofilm, carbapenemase, and extended-spectrum β-lactamase were examined. Genotypically, the biofilm-, outer membrane porin-, and some plasmid-correlated antimicrobial resistance genes were screened. About 50% of the isolates were multidrug-resistant while 98.4% were extended-spectrum β-lactamase producers and 89.3% were carbapenem-resistant. Unfortunately, 93.1% of the multidrug-resistant isolates produced different biofilm levels. Additionally, fimD and mrkD genes encoding adhesins were detected in 100% and 55.2% of the tested isolates, respectively. Also, the blaKPC, blaOXA-48-like, and blaNDM-encoding carbapenemases were observed in 16.1%, 53.6%, and 55.4% of the tested isolates, respectively. Moreover, the blaSHV and blaCTX-M extended-spectrum β-lactamase-associated genes were detected at 95.2% and 61.3%, respectively. Furthermore, aac(3)IIa, qnrB, and tetB resistance-correlated genes were observed in 38.1%, 46%, and 7.9% of the tested isolates, respectively. Certainly, the tested antimicrobial resistance-encoding genes were concurrently observed in 3.2% of the tested isolates. These findings confirmed the elevated prevalence of various antimicrobial resistance-associated genes in Klebsiella pneumoniae. The concurrent transferring of plasmid-encoding antimicrobial resistance-related genes could be associated with the possible acquisition of multidrug-resistant Klebsiella pneumoniae phenotypes.