Antibiotic coresistance in extended-spectrum-beta-lactamase-producing Enterobacteriaceae and in vitro activity of tigecycline

Epidemiology and clinical characteristics of patients with healthcare-acquired multidrug-resistant Gram-negative bacilli: a retrospective study from a tertiary care hospital

The numbers of infections caused by Gram-negative bacteria (GNB) that produce extended-spectrum beta-lactamases (ESBLs) and those that are carbapenem resistant, especially Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae), are increasing, and these infections are becoming a global public health problem. The aim of this study was to assess the prevalence of infections caused by ESBL-producing and carbapenem-resistant Gram-negative bacilli in patients hospitalized at An-Najah National University Hospital in Nablus, Palestine, and to provide healthcare workers with valuable information on the treatment of these infections. A retrospective cross-sectional investigation was conducted at a large tertiary care teaching hospital. The study included patients admitted to the hospital between January and December 2021, from whom ESBL-producing and carbapenem-resistant Gram-negative bacilli were isolated. The patients' clinical and demographic information was obtained from the hospital information system. In addition, information regarding the bacterial isolates and antibiotic resistance was obtained from the hospital's microbiology laboratory. This study included a total of 188 patients-91 males (48.4%) and 97 females (51.6%). The general surgical ward accounted for the highest proportion of infections (30.9%), followed by the surgical ICU (12.2%). The most common infections were caused by ESBL-producing E. coli, which accounted for 62.8% of the cases. Among them, urinary tract infections caused by this microorganism were the most prevalent (44.7% of patients). Over 50% of the patients (54.2%) had a history of antibiotic use, and 77.8% had been hospitalized within the past three months. ESBL-producing E. coli was significantly isolated from blood cultures (p-value = 0.000), and CR-K. pneumoniae was significantly isolated from endotracheal isolates (p-value = 0.001). This study emphasizes the concerning frequency of healthcare-acquired infections caused by ESBL-producing and carbapenem-resistant GNB in a tertiary care hospital. The substantial prevalence of antibiotic resistance presents considerable obstacles to the successful administration of routinely employed antibiotics. The results highlight the immediate need for improved antimicrobial stewardship and the implementation of infection control strategies to reduce the effects of multidrug-resistant GNB on patient well-being and public health.

Occurrence, Typing, and Resistance Genes of ESBL/AmpC-Producing Enterobacterales in Fresh Vegetables Purchased in Central Israel

Beta-lactam resistance can lead to increased mortality, higher healthcare expenses, and limited therapeutic options. The primary mechanism of beta-lactam resistance is the production of extended-spectrum beta-lactamases (ESBL) and AmpC beta-lactamases. The spread of beta-lactamase-producing Enterobacterales via the food chain may create a resistance reservoir. The aims of this study were to determine the prevalence of ESBL/AmpC-producing Enterobacterales in vegetables, to examine the association between EBSL/AmpC-producing bacteria and types of vegetables, packaging, and markets, and to investigate the genetic features of ESBL-producing isolates. The antibiotic susceptibilities were determined using VITEK. Phenotypic ESBL/AmpC production was confirmed using disk diffusion. ESBL-producing isolates were subjected to Fourier-transform infrared (FT-IR) spectroscopy and to whole genome sequencing using Oxford Nanopore sequencing technology. Of the 301 vegetable samples, 20 (6.6%) were positive for ESBL producers (16 Klebsiella pneumoniae and 4 Escherichia coli), and 63 (20.9%) were positive for AmpC producers (56 Enterobacter cloacae complex, 4 Enterobacter aerogenes/cancerogenus, and 3 Pantoea spp., Aeromonas hydrophila, and Citrobacter braakii). The blaCTX-M and blaSHV genes were most common among ESBL-producing isolates. The beta-lactamase genes of the ESBL producers were mainly carried on plasmids. Multilocus sequence typing and FT-IR typing revealed high diversity among the ESBL producers. AmpC producers were significantly more common in leafy greens and ESBL producers were significantly less common in climbing vegetables. The presence of ESBL/AmpC-producing Enterobacterales in raw vegetables may contribute to the dissemination of resistance genes in the community.

Drug resistance and extended-spectrum β-lactamase (ESBLs) - producing Enterobacteriaceae, Acinetobacter and Pseudomonas species from the views of one-health approach in Ethiopia: a systematic review and meta-analysis

BACKGROUND

Although antimicrobial resistance (AMR) bacteria present a significant and ongoing public health challenge, its magnitude remains poorly understood, especially in many parts of the developing countries. Hence, this review was conducted to describe the current pooled prevalence of drug resistance, multidrug- resistance (MDR), and Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, Acinetobacter, and Pseudomonas species in humans, the environment, and animals or food of animal origin in Ethiopia.

METHODS

PubMed, Google Scholar, and other sources were searched for relevant articles as per the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. A critical appraisal for screening, eligibility, and inclusion in the meta-analysis was made based on the Joanna Briggs Institute's (JBI) essential appraisal tools. The meta-analysis was done on Statistical Software Package (STATA) version 17.0.

RESULTS

A total of 33 research articles were included in this systematic review and meta-analysis. Escherichia coli, Klebsiella species, Acinetobacter, and Pseudomonas species were the most frequently reported bacteria from two or more sources. More than 50% of Klebsiella species and 25% to 89% of Escherichia coli from two or more sources were resistant to all analysed antibiotics, except carbapenems. Fifty-five percent (55%) to 84% of Acinetobacter species and 33% to 79% of Pseudomonas species from human and environmental sources were resistant to all analyzed antibiotics. Carbapenem resistance was common in Acinetobacter and Pseudomonas species (38% to 64%) but uncommon in Enterobacteriaceae (19% to 44%). Acinetobacter species (92%), Klebsiella species (86%), and Pseudomonas species (79%) from human sources, and Proteus species (92%), and Acinetobacter species (83%), from environmental sources, were the common multidrug-resistant isolates. About 45% to 67% of E. coli, Klebsiella, Acinetobacter, and Pseudomonas species from human and environmental sources were ESBL producers.

CONCLUSION

Our review report concluded that there was a significant pooled prevalence of drug resistance, MDR, and ESBL-producing Enterobacteriaceae, Acinetobacter, and Pseudomonas species from two or more sources. Hence, our finding underlines the need for the implementation of integrated intervention approaches to address the gaps in reducing the emergence and spread of antibiotic- resistant bacteria.

Bacterial Co-Infections and Antimicrobial Resistance in Patients Hospitalized with Suspected or Confirmed COVID-19 Pneumonia in Kazakhstan

Our study was carried out to characterize respiratory tract microbiota in patients with “COVID-like pneumonia” in Kazakhstan and analyze differences between COVID-19 positive and negative groups. Sputum samples were collected from hospitalized patients, ≥18 years old, in the three cities in Kazakhstan with the highest COVID-19 burden in July 2020. Isolates were identified by MALDI-TOF MS. Susceptibility testing was performed by disk diffusion. We used SPSS 26 and MedCalc 19 for statistical analysis. Among 209 patients with pneumonia, the median age was 62 years and 55% were male. RT-PCR-confirmed SARS-CoV-2 cases were found in 40% of patients, and 46% had a bacterial co-infection. Co-infection was not associated with SARS-CoV-2 RT-PCR test results, but antibiotic use was. The most frequent bacteria were Klebsiella pneumoniae (23%), Escherichia coli (12%), and Acinetobacter baumannii (11%). Notably, 68% of Klebsiella pneumoniae had phenotypic evidence of extended-spectrum beta-lactamases in disk diffusion assays, 87% of Acinetobacter baumannii exhibited resistance to beta-lactams, and >50% of E. coli strains had evidence of ESBL production and 64% were resistant to fluoroquinolones. Patients with a bacterial co-infection had a higher proportion of severe disease than those without a co-infection. The results reinforce the importance of using appropriate targeted antibiotics and effective infection control practices to prevent the spread of resistant nosocomial infections.

Development and Validation of a Nomogram for Predicting Tigecycline-Related Coagulopathy: A Retrospective Cohort Study

Background

Although tigecycline is an effective drug against drug-resistant bacteria, it demonstrated a higher all-cause mortality than comparator antibiotics and a high incidence of coagulation disorders which can be accompanied by severe bleeding. At present, a predictive model for tigecycline-related coagulopathy is not readily available, and the prognostic value of coagulopathy in tigecycline-administered patients has not been elucidated. In this paper, we investigate the association between tigecycline-related coagulopathy and in-hospital mortality to develop a nomogram for the prediction of tigecycline-related coagulopathy.

Methods

This retrospective cohort study includes 311 adults prescribed with tigecycline from 2018 to 2020. The primary cohort and validation cohort were constructed by dividing the participants in a ratio of 7:3. The endpoint is tigecycline-related coagulopathy, defined as a condition with no abnormality in coagulation prior to tigecycline application but developed the following symptoms upon prescription: activated partial thromboplastin time (APTT) extended by >10 s than the upper limit of normal (ULN), prothrombin time (PT) prolonged for >3 s than the ULN or reduced serum level of fibrinogen to <2.0 g/L. A predictive nomogram based on logistic regression was subsequently constructed.

Results

Tigecycline intake for over 7 days, combined other antibiotics, initial PT, initial fibrinogen and estimated glomerular filtration rate (eGFR), are independent prognostic factors of tigecycline-related coagulopathy. The primary and validation cohort each has an area under the receiver operating characteristic curve (AUC) of 0.792 (0.732-0.851) and 0.730 (0.629-0.832) for nomogram, respectively. Furthermore, the fitted calibration curve illustrated adequate fit of the model, while the decision curve analysis demonstrated good clinical value. Survival curves showed a high mortality rate among patients with tigecycline-related coagulopathy.

Conclusion

This nomogram exhibited helpful clinical value in predicting tigecycline-related coagulopathy that could reduce the high mortality rate of patients prescribed with tigecycline.

Evaluation of Tebipenem Hydrolysis by β-Lactamases Prevalent in Complicated Urinary Tract Infections

Tebipenem pivoxil is the first orally available carbapenem antibiotic and has been approved in Japan for treating ear, nose, and throat and respiratory infections in pediatric patients. Its active moiety, tebipenem, has shown potent antimicrobial activity in vitro against clinical isolates of Enterobacterales species from patients with urinary tract infections (UTIs), including those producing extended-spectrum β-lactamases (ESBLs) and/or AmpC β-lactamase. In the present study, tebipenem was tested for stability to hydrolysis by a set of clinically relevant β-lactamases, including TEM-1, AmpC, CTX-M, OXA-48, KPC, and NDM-1 enzymes. In addition, hydrolysis rates of other carbapenems, including imipenem, meropenem, and ertapenem, were determined for comparison. It was found that, similar to other carbapenems, tebipenem was resistant to hydrolysis by TEM-1, CTX-M, and AmpC β-lactamases but was susceptible to hydrolysis by KPC, OXA-48, and NDM-1 enzymes with catalytic efficiency values (k_cat/K_m) ranging from 0.1 to 2 × 10⁶ M^-1s^-1. This supports the reported results of antimicrobial activity of tebipenem against ESBL- and AmpC-producing but not carbapenemase-producing Enterobacterales isolates. Considering that CTX-M and AmpC β-lactamases represent the primary determinants of multidrug-resistant complicated UTIs (cUTIs), the stability of tebipenem to hydrolysis by these enzymes supports the utility of its prodrug tebipenem, tebipenem pivoxil hydrobromide (TBP-PI-HBr), as an oral therapy for adult cUTIs.

GENOMIC CHARACTERIZATION OF MULTIDRUG-RESISTANT EXTENDED-SPECTRUM β-LACTAMASE-PRODUCING ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE FROM CHIMPANZEES (PAN TROGLODYTES) FROM WILD AND SANCTUARY LOCATIONS IN UGANDA

Farm and wild animals may serve as reservoirs of antimicrobial-resistant bacteria of human health relevance. We investigated the occurrence and genomic characteristics of extended spectrum β-lactamase (ESBL)-producing bacteria in Ugandan chimpanzees (Pan troglodytes) residing in two environments with or without close contact to humans. The ESBL-producing Escherichia coli and Klebsiella pneumoniae were isolated from fecal material of chimpanzees from Budongo Forest and Ngamba Island Chimpanzee Sanctuary in Uganda and were more commonly isolated from chimpanzees in Ngamba Island Chimpanzee Sanctuary, where animals have close contact with humans. Selected ESBL isolates (E. coli n=9, K. pneumoniae n=7) were analyzed by whole-genome sequencing to determine the presence of resistance genes, as well as sequence type and virulence potential; the blaCTX-M-15 gene was present in all strains. Additionally, the ESBL genes blaSHV-11 and blaSHV-12 were found in strains in the study. All strains were found to be multidrug resistant. The E. coli strains belonged to four sequence types (ST2852, ST215, ST405, and ST315) and the K. pneumoniae strains to two sequence types (ST1540 and ST597). Virulence genes did not indicate that strains were of common E. coli pathotype, but strains with the same sequence types as isolated in the current study have previously been reported from clinical cases in Africa. The findings indicate that chimpanzees in close contact with humans may carry ESBL bacteria at higher frequency than those in the wild, indicating a potential anthropogenic transmission.

Characterization of cefotaxime-resistant urinary Escherichia coli from primary care in South-West England 2017-18

OBJECTIVES

Third-generation cephalosporin-resistant Escherichia coli from community-acquired urinary tract infections are increasingly reported worldwide. We sought to determine and characterize the mechanisms of cefotaxime resistance employed by urinary E. coli obtained from primary care, over 12 months, in Bristol and surrounding counties in South-West England.

METHODS

Cefalexin-resistant E. coli isolates were identified from GP-referred urine samples using disc susceptibility testing. Cefotaxime resistance was determined by subsequent plating onto MIC breakpoint plates. β-Lactamase genes were detected by PCR. WGS was performed on 225 isolates and analyses were performed using the Center for Genomic Epidemiology platform. Patient information provided by the referring general practices was reviewed.

RESULTS

Cefalexin-resistant E. coli (n=900) isolates were obtained from urines from 146 general practices. Following deduplication by patient approximately 69% (576/836) of isolates were cefotaxime resistant. WGS of 225 isolates identified that the most common cefotaxime-resistance mechanism was blaCTX-M carriage (185/225), followed by plasmid-mediated AmpCs (pAmpCs) (17/225), AmpC hyperproduction (13/225), ESBL blaSHV variants (6/225) or a combination of both blaCTX-M and pAmpC (4/225). Forty-four STs were identified, with ST131 representing 101/225 isolates, within which clade C2 was dominant (54/101). Ciprofloxacin resistance was observed in 128/225 (56.9%) of sequenced isolates, predominantly associated with fluoroquinolone-resistant clones ST131 and ST1193.

CONCLUSIONS

Most cefalexin-resistant E. coli isolates were cefotaxime resistant, predominantly caused by blaCTX-M carriage. The correlation between cefotaxime resistance and ciprofloxacin resistance was largely attributable to the high-risk pandemic clones ST131 and ST1193. Localized epidemiological data provide greater resolution than regional data and can be valuable for informing treatment choices in the primary care setting.

Resistance determinants and their genetic context in enterobacteria from a longitudinal study of pigs reared under various husbandry conditions

Pigs are major reservoirs of resistant Enterobacteriaceae that can reach humans through consumption of contaminated meat or vegetables grown in manure-fertilized soil. Samples were collected from sows during lactation and their piglets at five time points spanning the production cycle. Cefotaxime-resistant bacteria were quantified and isolated from feed, feces, manures and carcasses of pigs reared with penicillin-using or antibiotic-free husbandries. The isolates were characterized by antibiotic susceptibility testing, whole genome sequencing and conjugation assays. The extended spectrum β-lactamase (ESBL) phenotype was more frequent in isolates originating from antibiotic-free animals, while the bacteria isolated from penicillin-using animals were on average resistant to a greater number of antibiotics. The ESBL-encoding genes identified were bla _CTX-M-1, bla _CTX-M-15 and bla _CMY-2 and they co-localised on plasmids with various genes encoding resistance to ß-lactams, co-trimoxazole, phenicols and tetracycline, all antibiotics used in pig production. Groups of genes conferring the observed resistance and the mobile elements disseminating multidrug resistance were determined. The observed resistance to ß-lactams was mainly due to the complementary actions of penicillin-binding proteins, an efflux pump and ß-lactamases. Most resistance determinants were shared by animals raised with or without antimicrobials. This suggests a key contribution of indigenous enterobacteria maternally transmitted along the sow lineage, regardless of antimicrobial use. It is unclear if the antimicrobial resistance observed in the enterobacteria populations of the commercial pig herds studied were present before the use of antibiotics, or the extent to which historical antimicrobial use exerted a selective pressure defining the resistant bacterial populations in farms using penicillin prophylaxis.Importance: Antimicrobial resistance is a global threat that needs to be fought on numerous fronts along the One Health continuum. Vast quantities of antimicrobials are used in agriculture to ensure animal welfare and productivity, and are arguably a driving force for the persistence of environmental and food-borne resistant bacteria. This study evaluated the impact of conventional, organic and other antibiotic-free husbandry practices on the frequency and nature of antimicrobial resistance genes and multidrug resistant enterobacteria. It provides knowledge about the relative contribution of specific resistance determinants to observed antibiotic resistance. It also showed the clear co-selection of genes coding for extended-spectrum beta-lactamases and genes coding for the resistance to antibiotics commonly used for prophylaxis or in curative treatments in pig operations.

Measures used to assess the burden of ESBL-producing Escherichia coli infections in humans: a scoping review

Background

ESBL-producing bacteria pose a serious challenge to both clinical care and public health. There is no standard measure of the burden of illness (BOI) of ESBL-producing Escherichia coli (ESBL-EC) in the published literature, indicating a need to synthesize available BOI data to provide an overall understanding of the impact of ESBL-EC infections on human health.

Objectives

To summarize the characteristics of BOI reporting in the ESBL-EC literature to (i) describe how BOI associated with antimicrobial resistance (AMR) is measured and reported; (ii) summarize differences in other aspects of reporting between studies; and (iii) highlight the common themes in research objectives and their relation to ESBL-EC BOI.

Methods and results

Two literature searches, run in 2013 and 2018, were conducted to capture published studies evaluating the BOI associated with ESBL-EC infections in humans. These searches identified 1723 potentially relevant titles and abstracts. After relevance screening of titles and abstracts and review of full texts, 27 studies were included for qualitative data synthesis. This review identified variability in the reporting and use of BOI measures, study characteristics, definitions and laboratory methods for identifying ESBL-EC infections.

Conclusions

Decision makers often require BOI data to make science-based decisions for the implementation of surveillance activities or risk reduction policies. Similarly, AMR BOI measures are important components of risk analyses and economic evaluations of AMR. This review highlights many limitations to current ESBL-EC BOI reporting, which, if improved upon, will ensure data accessibility and usefulness for ESBL-EC BOI researchers, decision makers and clinicians.

Knowledge and use of antibiotics among low-income small-scale farmers of Peru

The extensive use and misuse of antibiotics in the livestock sector is one of the main drivers of the emergence and spread of antimicrobial resistance. Although small-scale farms constitute most of the livestock production in low and middle-income countries, knowledge and use of antibiotics among these populations is sparse. We conducted 201 questionnaires to estimate the use and knowledge of antibiotics by small-scale farmers located in the coastal area of the Lima region of Peru. Our results show that farmers had a small number of livestock (e.g. average of 11 cows, 7 pigs and 19 chickens per farm) and 80 % earned less than minimum wage. More than half of farmers reported at least one episode of respiratory disease, diarrhea, mastitis, skin lesion or post-parturition infection in their animals during the previous year, and 40 % of these episodes were treated with antibiotics. Farmers reported using 14 different antibiotics, most commonly oxytetracycline (31 % of episodes treated with antibiotics), penicillin (21 %), gentamicin (19 %) and trimethoprim-sulfamethazine (18 %). The third-generation cephalosporin ceftiofur was occasionally used to treat mastitis. Most farmers relied on veterinarians to prescribe (95 % of respondents) and administer (59 %) antibiotics. Only half of farmers knew what micro-organisms can be treated with antibiotics and the degree of knowledge of antibiotics (based on a 5-question metric) was positively correlated with respondents’ educational level, monthly income, knowledge of the animal health authority, farm area, number of cows and knowledge of an antiparasitic drug. In contrast, knowledge of antibiotics was not correlated with respondents’ age, gender, main occupation, knowledge of a veterinarian or household size. Potential misuse of antibiotics was reported, including 21 % of framers reporting stopping the treatment when clinical signs disappear and infrequent use of antibiotics to treat parasites or animals not eating. Our study highlights poor knowledge and potential misuse of antibiotics among small-scale farmers in coastal Peru, but high reliance on veterinarians for prescription and administration. Strengthening farmers' relationships with veterinarians and improving the diagnostic capacity of the veterinary sector could result in more judicious antibiotic use on these farms.

A Retrospective Analysis of Risk Factors and Patient Outcomes of Bloodstream Infection with Extended-Spectrum β-Lactamase-Producing Escherichia coli in a Chinese Tertiary Hospital

Objective

The present study assessed risk factors and patient outcomes of bloodstream infection (BSI) caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli).

Methods

A retrospective study was performed to analyze risk factors and patient outcomes of BSI caused by extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) in one Chinese tertiary hospital over a 7.5-year period. The clinical characteristics of patients infected with ESBL-producing and non-ESBL-producing E. coli were compared. Predictors of 30-day mortality in patients with E. coli BSI were also identified in our study.

Results

The results of drug sensitivity showed that quinolones, aminoglycosides, β-lactam/β-lactamase inhibitor combinations (BLICs) and trimethoprim/sulfamethoxazole exhibited significant differences between the ESBL and non-ESBL groups. Of the 963 patients with E. coli BSI, 57.6% developed ESBL-EC. Multivariate analysis showed that biliary tract infection (BTI) [P<0.001,OR (95% CI):1.798 (1.334–2.425)], urinary tract obstructive disease [P=0.001,OR (95% CI):2.106 (1.366–3.248)], surgery within 3 months [P=0.002,OR (95% CI):1.591 (1.178–2.147)], hospitalization within 3 months [P<0.001,OR (95% CI):2.075 (1.579–2.725)], ICU admission [P=0.011,OR (95% CI):1.684 (1.124–2.522)] and history of cephalosporin use [P=0.006,OR (95% CI):3.097 (1.392–6.891)] were statistically significant. In mortality analysis, aCCI>2 [P=0.016,OR (95% CI): 2.453 (1.179–5.103)], gastrointestinal catheterization [P=0.004, OR (95% CI): 2.525 (1.333–4.782)] were significantly associated with 30-day mortality. According to Kaplan-Meier survival analysis, we found that in SOFA<2 group and SOFA≥2 group, the mortality rate of patients treated with BLICs were lower than that of carbapenems(P<0.05).

Conclusion

This study showed that BTI, urinary tract obstructive disease, surgery within 3 months, hospitalization within 3 months, ICU admission and cephalosporin exposure were independent risk factors for the emergence of ESBL-EC BSI. Analysis of risk factors for 30-day mortality revealed that the factors independently associated with a higher risk of mortality were aCCI>2, gastrointestinal catheterization. Compared to carbapenems, the BLICs had preferable effect to treat patients with ESBL-EC BSI. Notably, patients with severe illness were inlcined to use carbapenems, which affected the analysis results. Therefore, we suggest that BLICs could be recommended to treat mild patients with ESBL-EC bacteremia.

Extended-spectrum β-lactamase-producing Escherichia coli isolated from raw vegetables in South Korea

The increasing prevalence of oxyimino-cephalosporin-resistant Enterobacteriaceae has become a global concern because of their clinical impact on both human and veterinary medicine. The present study determined the prevalence, antimicrobial susceptibility, and molecular genetic features of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) isolates from raw vegetables. A total of 1324 samples were collected from two agricultural wholesale markets in Incheon, South Korea in 2018. The ESBL-EC strains were isolated from 0.83% (11/1324) samples, and all of them were resistant to ampicillin, piperacillin, cefazoline, cefotaxime, and nalidixic acid and yielded CTX-M-type ESBL, including CTX-M-14, CTX-M-15, CTX-M-55, CTX-M-27, and CTX-M-65. The isolates belonged to phylogenetic subgroups D (n = 5), A (n = 4), and B1 (n = 2). Multilocus sequence typing revealed nine known E. coli sequence types (STs), including ST10, ST38, ST69, ST101, ST224, ST349, ST354, ST2509, ST2847, and two new STs. Notably, ST69, ST10, ST38, and ST354 belong to the major human-associated extraintestinal pathogenic E. coli lineages. Our results demonstrate that ESBL-producing multidrug-resistant pathogens may be transmitted to humans through the vegetable intake, highlighting the importance of resistance monitoring and intervention in the One Health perspective.

The Transcriptomic Signature of Tigecycline in Acinetobacter baumannii

Tigecycline, a protein translation inhibitor, is a treatment of last resort for infections caused by the opportunistic multidrug resistance human pathogen Acinetobacter baumannii. However, strains resistant to tigecycline were reported not long after its clinical introduction. Translation inhibitor antibiotics perturb ribosome function and induce the reduction of (p)ppGpp, an alarmone involved in the stringent response that negatively modulates ribosome production. Through RNA sequencing, this study revealed a significant reduction in the transcription of genes in citric acid cycle and cell respiration, suggesting tigecycline inhibits or slows down bacterial growth. Our results indicated that the drug-induced reduction of (p)ppGpp level promoted the production but diminished the degradation of ribosomes, which mitigates the translational inhibition effect by tigecycline. The reduction of (p)ppGpp also led to a decrease of transcription coupled nucleotide excision repair which likely increases the chances of development of tigecycline resistant mutants. Increased expression of genes linked to horizontal gene transfer were also observed. The most upregulated gene, rtcB, involving in RNA repair, is either a direct tigecycline stress response or is in response to the transcription de-repression of a toxin-antitoxin system. The most down-regulated genes encode two β-lactamases, which is a possible by-product of tigecycline-induced reduction in transcription of genes associated with peptidoglycan biogenesis. This transcriptomics study provides a global genetic view of why A. baumannii is able to rapidly develop tigecycline resistance.

Prevalence of multidrug-resistant and extended-spectrum beta-lactamase (ESBL)-producing gram-negative bacilli: A meta-analysis report in Ethiopia

Multidrug-resistant (MDR) extended-spectrum beta-lactamase (ESBL)-producing bacterial isolates have emerged as a global threat to human health. Little is known about the overall prevalence of multidrug resistance profile and ESBL-producing gram-negative bacilli (GNB) in Ethiopia. Therefore, this meta-analysis was performed to produce proportional estimates of multidrug resistance and ESBL-producing GNB in Ethiopia. A web-based search was conducted in PubMed, Google Scholar, Research Gate, Scopus and other databases. Articles published till 2019 on the prevalence and antimicrobial resistance profiles of ESBL-producing GNB in Ethiopia were included in the study. Relevant data were extracted and statistical analysis was performed using comprehensive meta-analysis version 3.3.0 software. Publication bias was analyzed and presented with funnel plots. In this meta-analysis, the overall proportional estimate of ESBL-producing GNB was 48.9% (95% confidence interval [CI]: 0.402, 0.577). The pooled proportional estimates of ESBL-producing Klebsiella pneumoniae, Escherichia coli and other GNB were 61.8%, 41.2% and 42.9%, respectively. Regarding antimicrobial resistance profiles against selected drugs, the pooled proportional estimates of resistance against amoxicillin-clavulanic acid, trimethoprim-sulfamethoxazole, cefotaxime, ceftazidime, tetracycline, gentamicin and ciprofloxacin was 79.0%, 78.4%, 78.0%, 72.4%, 72.7%, 58.9% and 43.8%, respectively. The pooled proportional estimates of MDR isolates were found to be 82.7% (95% CI: 0.726, 0.896), which are relatively high as compared to other countries. This highlights a need for active surveillance systems which can help understand the actual epidemiology of ESBL, aid in formulating national guidelines for proper screening of ESBL and support developing standardized approaches for managing patients colonized with ESBL.

Sitafloxacin has a potent activity for eradication of extended spectrum β-lactamase-producing fluoroquinolone-resistant Escherichia coli forming intracellular bacterial communities in uroepithelial cells

INTRODUCTION

Eradication of asymptomatic bacteriuria (ASB) before urological procedures is important to reduce the risk for infectious complications after surgery. However, the appropriate regimen for antimicrobial treatment has not been fully determined. We experienced continuous (over 10 months) isolation of extended spectrum β-lactamase (ESBL)-producing fluoroquinolone-resistant Escherichia coli from urine of an asymptomatic patient. The four isolates obtained (SMESC1 to 4) were international high-risk clones of O25b:H4-ST131-H30R, and originated from one strain, as revealed by the whole genome sequences. Although the patient received meropenem (MEPM) and fosfomycin (FOM), to which the strains were susceptible before the urological procedures, they could not be eradicated.

METHODS

To explore the reason for the continuous isolation even after MEPM and FOM administration, antimicrobial killing of adherent and/or intracellular bacterial communities (IBC) formed by coculture of the E. coli cells and T24 bladder epithelial cells were examined.

RESULTS

FOM and levofloxacin did not decrease viable E. coli cells compared with gentamicin. MEPM partly decreased them, and sitafloxacin (STFX) decreased them most potently. These observations indicate that E. coli can survive in the urinary tract under antimicrobial administration, and some antimicrobials such as FOM and MEPM cannot eradicate E. coli in uroepithelial cells. Adhesion on urinary epithelial cells and/or IBC formation might result in continuous isolation from the urinary tract and recurrence of ASB and urinary tract infections.

CONCLUSIONS

The present study suggests that STFX is a promising optional agent for the eradication of ESBL-producing fluoroquinolone-resistant E. coli in the urinary tract before urological procedures.

The complex genetic region conferring transferable antibiotic resistance in multidrug-resistant and extremely drug-resistant Klebsiella pneumoniae clinical isolates

Antibiotic resistance due to transferable resistance genes is one of the most important concerns in Klebsiella pneumoniae isolated from nosocomial infections. Eighty-eight K. pneumoniae isolates were confirmed through biochemical methods. In addition, antimicrobial susceptibility testing was performed using a disc-diffusion method. Extended-spectrum β-lactamase production among the isolates was screened using a double-disc synergism test, and the resistance genes were identified using PCR. The eight loci for multiple-locus variable number tandem repeat analysis (MLVA) genotyping were selected along with the primers. According to our findings, neomycin (5; 5.6%) and carbapenems (10; 11.3%) showed the most remarkable inhibitory effect but co-trimoxazole (46; 52.2%) was the least effective antibiotic against K. pneumoniae isolates. bla _CTX-M-1 , qnrA, qnrB, qnrS, intI, intII, aac3 and aac6 were detected in 30 (34%), 5 (5.6%), 29 (32.9%), 23 (26.1%), 88 (100%), 72 (81.8%), 26 (29.5%) and 28 (31.8%) of the 88 isolates, respectively. But none of the K. pneumoniae isolates expressed the intIII gene. Using MLVA, 23 MLVA types and eight clusters were identified. Extended-spectrum β-lactamase-producing K. pneumoniae isolates were classified into two clonal complexes. Effective strategies for infection control should be applied to monitor and control the spread of multidrug-resistant isolates by the resistance genes located on the mobile genetic elements.

Clinically Relevant Extended-Spectrum β-Lactamase-Producing Escherichia coli Isolates From Food Animals in South Korea

Extended-spectrum β-lactam antimicrobials have been broadly used in food animals and humans to control infectious diseases. However, the emergence and rapid spread of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, mainly Escherichia coli, have seriously threatened global health in recent decades. In this study, we determined the prevalence, antimicrobial susceptibility, and genetic properties of ESBL-producing E. coli (ESBL-EC) strains isolated from food animals in South Korea. A total of 150 fecal samples from healthy chickens (n = 34), pigs (n = 59), and cattle (n = 57) were screened from January to July 2018. Among these, 77 non-duplicate cefotaxime-resistant ESBL-EC strains were isolated from 32 chicken, 41 pig, and 4 cattle samples, with the corresponding occurrence rates of 94.1, 69.5, and 7.0%, respectively. All the isolates showed multidrug resistance (MDR) and produced at least one type of β-lactamase, including CTX-M (98.7%) and TEM (40.3%). CTX-M-14 (53.1%), CTX-M-55 (53.7%), and CTX-M-65 (50.0%) were the predominant genotypes in the chicken, pig, and cattle samples, respectively. Multilocus sequence typing revealed 46 different sequence types (STs), including the human-associated extraintestinal pathogenic E. coli ST131 (n = 2), ST10 (n = 5), ST38 (n = 1), ST410 (n = 4), ST354 (n = 2), ST58 (n = 3), ST117 (n = 1), and ST457 (n = 1). To the best of our knowledge, this is the first report of pandemic E. coli ST131 in non-human isolates in South Korea. Our results demonstrate the high prevalence and diversity of MDR-ESBL-EC in food animals and highlight them as potential pathogenic ESBL-EC reservoirs that may pose a high risk to human health.

Resistance Patterns and Phenotypic Detection of β-lactamase Enzymes among Enterobacteriaceae Isolates from Referral Hospitals in Khartoum State, Sudan

Background Beta-lactamase enzymes-producing Enterobacteriaceae have emerged in many hospital settings resulting in poor treatment outcomes. We aimed to determine resistant patterns of Beta-lactamase enzymes among Enterobacteriaceae collected from referral hospitals in Khartoum state, Sudan. Methods A total of 168 Enterobacteriaceae recovered from clinical samples of patients during May 2014 to February 2015. Identification and susceptibility testing of the isolates were performed as per standard methods. Double-disk synergy test was applied to determine the presence of extended-spectrum β-lactamase (ESBL) production. AmpC beta-lactamases and carbapenemase were screened using AmpC disk test and the modified Hodge test, respectively. Results ESBL-producing Enterobacteriaceae represented 45.2%, with a higher rate among K. pneumoniae. AmpC beta-lactamase detected as 49.3%, with peak levels among Acinetobacter baumannii (A. baumannii) (83.3%) and Enterobacter cloacae (75%). Carbapenemase production was found among 74.5% of isolates, with high rates among A. baumannii (89%) and K. pneumoniae (78%). Overall Enterobacteriaceae, highest resistance rates were found in penicillins and cephalosporins agents. Amikacin and imipenem revealed good activities against most of the isolates, except for A. baumannii (66.7% and 75%, respectively). E. coli yielded high resistance rates for amoxicillin (98.8%), amoxicillin-clavulanic acid (93.8%), cefotaxime (93.8%), and ciprofloxacin (76.5%). Moderate resistance rates were observed among K. pneumoniae for ciprofloxacin (61.5%), nitrofurantoin (57.7%) and cefoxitin (40.4%). Conclusions ESBL, AmpC beta-lactamase and carbapenemase-producing Enterobacteriaceae are emerging and may contribute to increasing antimicrobial resistance in Sudan. Phenotypic screening of such enzymes is rapid and straightforward and should be simultaneously done and carried out routinely in our hospitals.

Molecular Characterization of Extended-Spectrum β-Lactamase Enterobacteriaceae Isolated from Egyptian Patients with Community- and Hospital-Acquired Urinary Tract Infection

Extended-spectrum β-lactamases (ESβLs) pose a serious problem in the treatment of urinary tract infections (UTIs). The ESβL-producing organism is an expanding global health problem. Therefore, screening for ESβL, detection of their drug-resistance pattern, and molecular characterization should be a continuous process. The present study was performed to determine the antibiotic resistance profile and the genetic characterization of ESβL isolates from hospital- and community-acquired UTIs. Two hundred fifty Enterobacteriaceae isolates were obtained from urine samples of outpatient clinic attendants and hospitalized patients at Kasr Al-Aini Hospital. By phenotypic screening tests, 100 ESβL isolates were detected among the studied groups. Furthermore, detection of beta-lactamase (bla) cefotaxime (CTX)-M, sulfhydryl variable, and temoneira ESβL genes was investigated by polymerase chain reaction. A subset of 25 CTX-M-positive isolates was further identified by gene sequencing technology. Among the 100 ESβL isolates, 66% were Escherichia coli and 34% were Klebsiella spp. There was no statistical difference in the prevalence of ESβL Enterobacteriaceae in community-acquired versus hospital-acquired UTIs. The susceptibility of all ESβL isolates to carbapenems was the most prevalent finding. In addition, all ESβL E. coli isolates were susceptible to fosfomycin, whereas all community-acquired ESβL isolates were susceptible to nitrofurantoin. A total of 98% of the ESβL isolates harbored bla-CTX-M genes, with CTX-M-15 being the most prevalent. It could be concluded that ESβL production is present at a high rate among Egyptian patients with hospital- and community-acquired UTI. The high prevalence of bla-CTX-M may suggest it as a candidate for molecular screening of ESβL.

The burden of antimicrobial resistance among urinary tract isolates of Escherichia coli in the United States in 2017

Urinary tract infections (UTIs) caused by Escherichia coli have been historically managed with oral antibiotics including the cephalosporins, fluoroquinolones and trimethoprim-sulfamethoxazole. The use of these agents is being compromised by the increase in extended spectrum β-lactamase (ESBL)-producing organisms, mostly caused by the emergence and clonal expansion of E. coli multilocus sequence typing (ST) 131. In addition, ESBL isolates show co-resistance to many of oral agents. Management of UTIs caused by ESBL and fluoroquinolone-resistant organisms is becoming increasingly challenging to treat outside of the hospital setting with clinicians having to resort to intravenous agents. The aim of this study was to assess the prevalence of ESBL phenotypes and genotypes among UTI isolates of E. coli collected in the US during 2017 as well as the impact of co-resistance to oral agents such as the fluoroquinolones and trimethoprim-sulfamethoxazole. The national prevalence of ESBL phenotypes of E. coli was 15.7% and was geographically distributed across all nine Census regions. Levofloxacin and trimethoprim-sulfamethoxazole-resistance rates were ≥ 24% among all isolates and this co-resistance phenotype was considerably higher among isolates showing an ESBL phenotype (≥ 59.2%) and carrying bla_CTX-M-15 (≥ 69.5%). The agents with the highest potency against UTI isolates of E. coli, including ESBL isolates showing cross-resistance across oral agents, were the intravenous carbapenems. The results of this study indicate that new oral options with the spectrum and potency similar to the intravenous carbapenems would address a significant unmet need for the treatment of UTIs in an era of emergence and clonal expansion of ESBL isolates resistant to several classes of antimicrobial agents, including oral options.

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae and urinary tract infections in pregnant/postpartum women: A systematic review and meta-analysis

BACKGROUND

Urinary tract infections (UTI) and asymptomatic bacteriuria (AB) during pregnancy can result in considerable maternal and foetal adverse outcomes. Production of extended-spectrum beta-lactamase (ESBL) is a major antibiotic resistance mechanism by Enterobacteriaceae.

OBJECTIVES

To determine the global prevalence of ESBL-producing (ESBL-P) Enterobacteriaceae in symptomatic UTI/AB among pregnant/postpartum females.

DATA SOURCES

A systematic review of the PubMed, Embase, Scopus, WOS (Web of Science), ProQuest and the grey literature was conducted.

STUDY SELECTION AND DATA EXTRACTION

Studies that reported the frequency of ESBL-P Enterobacteriaceae in pregnant/postpartum women with UTI and/or AB were eligible. First, the titles and abstracts of the retrieved articles were reviewed. Then, the full texts of the remained articles were reviewed.

SYNTHESIS

In order to estimate the pooled prevalence and the 95% confidence interval (95% CI), meta-analysis was performed using the random-effects model.

RESULTS

Twenty-three studies (six from Africa, two from North America, one from South America, 12 from Asia and two European studies) that reported data on 20 033 Enterobacteriaceae strains were included. The pooled prevalence of ESBL-P Enterobacteriaceae was 25% (95% CI 18%, 32%); I2  = 98.8%. The estimated prevalence (95% CI) rates were 45% (22, 67%) in Africa, 33% (22, 44%) in India, 15% (6, 24%) in other Asian countries, 5% (2, 8%) in Europe, 4% (1, 11%) in South America and 3% (1, 5%) in North America (P < .001). This estimate was 21% (95% CI 11, 31%) in patients with symptomatic UTI and it was 28% (95% CI 15, 41%) in patients with AB (P = .40).

CONCLUSIONS

The prevalence of ESBL-P Enterobacteriaceae among pregnant women with UTI/AB was significant and geographic region was a major source for heterogeneity. The findings could be taken into account by healthcare providers and programmers in the management and antibiotic selection of UTI/AB during pregnancy, especially in high prevalence areas.

Pharmacodynamics of Tebipenem: New Options for Oral Treatment of Multidrug-Resistant Gram-Negative Infections

Tebipenem pivoxil HBr (TBPM-PI-HBr) is a novel orally bioavailable carbapenem. The active moiety is tebipenem. Tebipenem pivoxil is licensed for use in Japan in children with ear, nose, and throat infections and respiratory infections. The HBr salt was designed to improve drug substance and drug product properties, including stability. TBPM-PI-HBr is now being developed as an agent for the treatment of complicated urinary tract infections (cUTI) in adults. The pharmacokinetics-pharmacodynamics of tebipenem were studied in a well-characterized neutropenic murine thigh infection model. Plasma drug concentrations were measured using liquid chromatography-tandem mass spectrometry. Dose fractionation experiments were performed after establishing dose-response relationships. The magnitude of drug exposure required for stasis was established using 11 strains of Enterobacteriaceae (Escherichia coli, n = 6; Klebsiella pneumoniae, n = 5) with a variety of resistance mechanisms. The relationship between drug exposure and the emergence of resistance was established in a hollow-fiber infection model (HFIM). Tebipenem exhibited time-dependent pharmacodynamics that were best described by the free drug area under the concentration-time curve (fAUC_0-24)/MIC corrected for the length of the dosing interval (fAUC_0-24/MIC · 1/tau). The pharmacodynamics of tebipenem versus E. coli and K. pneumoniae were comparable, as was the response of strains possessing extended-spectrum β-lactamases versus the wild type. The median fAUC_0-24/MIC · 1/tau value for the achievement of stasis in the 11 strains was 23. Progressively more fractionated regimens in the HFIM resulted in the suppression of resistance. An fAUC_0-24/MIC · 1/tau value of 34.58 to 51.87 resulted in logarithmic killing and the suppression of resistance. These data and analyses will be used to define the regimen for a phase III study of adult patients with cUTI.

Cefmetazole for extended-spectrum β-lactamase-producing Enterobacteriaceae in pediatric pyelonephritis

BACKGROUND

Pyelonephritis caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is an urgent problem in pediatrics. Although carbapenem is the standard therapy for infections caused by ESBL-producing Enterobacteriaceae, some cephamycins, including cefmetazole, are stable against hydrolysis by ESBL. There are few reports, however, on the use of cefmetazole in children. The aim of this study was to evaluate the therapeutic effect of cefmetazole in pediatric pyelonephritis caused by ESBL-producing Enterobacteriaceae.

METHODS

Children with pyelonephritis caused by ESBL-producing Enterobacteriaceae were enrolled between April 2010 and November 2016 at Tokyo Metropolitan Children's Medical Center. Presence of ESBL was tested for using the disk diffusion method. Medical records were reviewed for a past history of bacterial infection. The outcomes were clinical cure rate at 4 weeks and the duration of therapy in the cefmetazole and non-cefmetazole groups.

RESULTS

Fifty-five patients met the criteria for pyelonephritis caused by ESBL-producing Enterobacteriaceae. The most common causative organisms were Escherichia coli (n = 51; 92.7%), Klebsiella pneumoniae (n = 3; 5.5%), and K. oxytoca (n = 1; 1.8%). Thirty-six and 19 patients were treated with cefmetazole and with other antibiotics as definitive therapy, respectively. There was no difference in the clinical cure rate (86.1% vs 89.5%; P = 0.72) or duration of therapy (median, 7.0 vs 7.0 days; P = 0.73) between the cefmetazole and non-cefmetazole groups.

CONCLUSIONS

Cefmetazole was not inferior to the other antibiotics in the treatment of pyelonephritis caused by ESBL-producing Enterobacteriaceae in children. Cefmetazole is a valuable therapeutic alternative to carbapenems for treating pyelonephritis caused by ESBL-producing Enterobacteriaceae.

Genetic Study of Extended Spectrum Beta-Lactamase and Carbapenemase Producing Escherichia Coli Causing Sepsis among Egyptian Children

Background:

Treatment failure of sepsis caused by Escherichia coli (E. Coli) is a leading cause of death of infants and children in intensive care units.

Objective:

To detect the prevalence of Extended-Spectrum Beta-Lactamase (ESBL) and carbapenemase-genes between E. coli isolates from infants and children with septicemia and to identify their antibiotic sensitivity pattern.

Methods:

This is a cross-sectional study performed on 88 patients with sepsis. The isolated E. coli were identified by Gram stain and biochemically by the Microscan automated system. ESBL and carbapenemase producing E. coli were isolated on double disk diffusion and EDTA double disk, respectively. Polymerase chain reaction for ESBL and carbapenemase producing E. coli genes were performed. Bacterial susceptibility to antibiotics was tested. The initial results were measured through the 30-days of hospital admission. IRB approved the study.

Results:

Of 88 patients with sepsis, 49 and 30 strains were ESBL producing and carbapenemase producing E. coli; respectively. Neither risk factors for infection nor clinical picture can differentiate between ESBL and carbapenemase producing E. coli. The most frequently detected gene of ESBL producing E. coli was SHV, it was more sensitive to Piperacillin/Tazobactam (90%) and cefepime (86.7%) while for carbapenemase-producing E. coli; IMP was the most frequent, its sensitivity was high to Piperacillin/Tazobactam and Ciprofloxacin (52.6% each).

Conclusion:

The commonest gene of ESBL producing E. coli is SHV whereas for carbapenemase-producing E. coli is IMP. Piperacillin/Tazobactam is the candidate drug to start in children with septicemia and suspected ESBL or carbapenemase-producing E. coli infection.

High Prevalence of CTX-M-15-Type Extended-Spectrum β-Lactamase Among AmpC β-Lactamase-Producing Klebsiella pneumoniae Isolates Causing Bacteremia in Korea

We investigated the antimicrobial susceptibility, the genotypic distributions of extended-spectrum β-lactamase (ESBL) and AmpC genes, and the molecular epidemiology of AmpC-producing Klebsiella pneumoniae (AmpC-KP) isolates causing bacteremia. Among 260 K. pneumoniae clinical isolates included in this study, plasmid-mediated AmpC β-lactamases were found in 20.7% (54/260), which included DHA-1 (96.3%, 52/54), CMY-2 (3.7%, 2/54), and CMY-10 (1.9%, 1/54). One isolate also produced DHA-1 along with CMY-2. Of the 54 AmpC-KP isolates, 31 isolates (57.4%) showed ESBL positivity. Of these 31 isolates with coproduction of ESBL and AmpC β-lactamases, 25 isolates (80.6%) produced CTX-M-15 in addition to DHA-1. Nine isolates (29.0%) were nonsusceptible to imipenem. The most prevalent sequence type (ST) was ST11 (n = 31, 57.4%), followed by ST2361 (n = 5, 9.3%), which was newly identified in this study, and ST48 (n = 4, 7.4%). K. pneumoniae isolates coproducing DHA-1 and CTX-M-15 have emerged and disseminated in Korean hospitals, even in blood isolates causing bacteremia. Such infections may become a challenge for clinicians because there is a severely restricted range of available therapeutic options for these pathogens.

The evolution of antimicrobial resistance in Salmonella Typhi

PURPOSE OF REVIEW

Increasing antimicrobial resistance in Salmonella Typhi is a serious public health concern, especially in industrializing countries. Here we review recent clinical and laboratory data concerning the evolution of antimicrobial resistance, with particular reference to the emergence resistance against fluoroquinolones, third generation cephalosporins, and azithromycin.

RECENT FINDINGS

The last 40 years have witnessed the sequential emergence of resistance to all first-line antimicrobials used in the treatment of S. Typhi infections. Multidrug resistance (MDR), defined by resistance to chloramphenicol, amoxicillin, and co-trimoxazole, emerged in the 1990s, followed rapidly by reduced susceptibility to fluoroquinolones. In the current decade, high-level fluoroquinolone resistance has emerged in south Asia and threatens to spread worldwide. Increasing reliance is now being placed on the activity of third generation cephalosporins and azithromycin, but resistance against these agents is developing. Carbapenems and tigecycline may be alternatives, although clinical data are sparse, and in some settings reversion to chloramphenicol and co-trimoxazole susceptibility is occurring. Therefore, older drugs may yet have a role in the treatment of S. Typhi infections.

SUMMARY

Good surveillance, improved diagnostics, more prudent use of antimicrobials, and effective vaccines will all be critical to reducing the burden of disease caused by S. Typhi.

Polymerase chain reaction detection of genes responsible for multiple antibiotic resistance Staphylococcus aureus isolated from food of animal origin in Egypt

Aim:

The aim of our study was polymerase chain reaction (PCR) detection of the genes responsible for the multiple antibiotic resistance S. aureus isolated from food of animal origin in Egypt.

Materials and Methods:

A total of 125 samples were randomly collected from milk, meat, and their products from Giza and Beni-Suef Governorates markets. The S. aureus isolates were subjected to antimicrobial sensitivity tests using four antibacterial disks (Oxoid), and then the polymerase chain reaction (PCR) was performed for detection of antibiotic resistance genes.

Results:

Out of 125 samples, 19 S. aureus isolates were detected. All detected isolates were multiple drug resistance (MDR). The penicillin-, erythromycin-, kanamycin-, and tetracycline-resistant isolates were examined by PCR for resistance genes blaZ, (msrA, ermB, and ermC), aac(6’)aph (2”), and tetK. The isolates harbored these resistance genes with percentage of 100% (100%, 0%, and 100%), 62.5%, and 100%, respectively.

Conclusion:

Contaminated foods of animal origin may represent a source of MDR S. aureus that can be a major threat to public health.

Randomized controlled trial of piperacillin-tazobactam, cefepime and ertapenem for the treatment of urinary tract infection caused by extended-spectrum beta-lactamase-producing Escherichia coli

BACKGROUND

Due to limited therapeutic options, the spread of extended-spectrum beta-lactamases (ESBLs) have become a major public health concern. We conducted a prospective, randomized, open-label comparison of the therapeutic efficacy of piperacillin-tazobactam (PTZ), cefepime, and ertapenem in febrile nosocomial urinary tract infection with ESBL-producing Escherichia coli (ESBL-EC).

METHODS

This study was conducted at three university hospitals between January 2013 and August 2015. Hospitalized adult patients presenting with fever were screened for healthcare-associated urinary tract infection (HA-UTI). When ESBL-EC was solely detected and susceptible to a randomized antibiotic in vitro, the case was included in the final analysis. Participants were treated for 10-14 days with PTZ, cefepime, or ertapenem.

RESULTS

A total of 66 participants were evenly assigned to the PTZ and ertapenem treatment groups. After the recruitment of six participants, assignment to the cefepime treatment group was stopped because of an unexpectedly high treatment failure rate. The baseline characteristics of these participants did not differ from participants in other treatment groups. The clinical and microbiological response to PTZ treatment was estimated to be 94% and was similar to the response to ertapenem treatment. The efficacy of cefepime was 33.3%. In the cefepime group, age, Charlson comorbidity index, genotype, and minimal inhibitory concentration (MIC) did not significantly affect the success of treatment. Similarly, genotype seemed to be irrelevant with respect to clinical outcome in the PTZ group. Expired cases tended to involve septic shock with a high Charlson comorbidity index and high MIC.

CONCLUSION

Results from this study suggest that PTZ is effective in the treatment of urinary tract infection caused by ESBL-EC when the in vitro test indicates susceptibility. In addition, cefepime should not be used as an alternative treatment for urinary tract infection caused by ESBL-EC.

TRIAL REGISTRATION

The trial was registered with the Clinical Research Information Service of Korea Centers for Disease Control and Prevention. (KCT0001895).

The Impact of Antibiotic Stewardship Programs in Combating Quinolone Resistance: A Systematic Review and Recommendations for More Efficient Interventions

Quinolones are among the most commonly prescribed antibiotics worldwide. A clear relationship has been demonstrated between excessive quinolone use and the steady increase in the incidence of quinolone-resistant bacterial pathogens, both in hospital and community sites. In addition, exposure to quinolones has been associated with colonization and infection with healthcare-associated pathogens such as methicillin-resistant Staphylococcus aureus and Clostridium difficile in hospitalized patients. Therefore, the management of quinolone prescribing in hospitals through antibiotic stewardship programs is considered crucial. Although suggestions have been made by previous studies on the positive impact of stewardship programs concerning the emergence and spread of multidrug-resistant bacteria at hospital level, the association of quinolone-targeted interventions with reduction of quinolone resistance is vague. The purpose of this article was to evaluate the impact of stewardship interventions on quinolone resistance rates and healthcare-associated infections, through a literature review using systematic methods to identify and select the appropriate studies. Recommendations for improvements in quinolone-targeted stewardship programs are also proposed. Efforts in battling quinolone resistance should combine various interventions such as restriction formulary policies, prospective audits with feedback to prescribers, infection prevention and control measures, prompt detection of low-level resistance, educational programs, and guidelines for optimal quinolone usage. However, the effectiveness of such strategies should be assessed by properly designed and conducted clinical trials. Finally, novel approaches in diagnostic stewardship for rapidly detecting bacterial resistance, including PCR-based techniques, mass spectrometry, microarrays, and whole-genome sequencing as well as the prompt investigation on the clonality of quinolone-resistant strains, will strengthen our ability to personalize quinolone prescribing to individual patients.

Fitness costs associated with the acquisition of antibiotic resistance

Acquisition of antibiotic resistance is a relevant problem for human health. The selection and spread of antibiotic-resistant organisms not only compromise the treatment of infectious diseases, but also the implementation of different therapeutic procedures as organ transplantation, advanced surgery or chemotherapy, all of which require proficient methods for avoiding infections. It has been generally accepted that the acquisition of antibiotic resistance will produce a general metabolic burden: in the absence of selection, the resistant organisms would be outcompeted by the susceptible ones. If that was always true, discontinuation of antibiotic use would render the disappearance of resistant microorganisms. However, several studies have shown that, once resistance emerges, the recovery of a fully susceptible population even in the absence of antibiotics is not easy. In the present study, we review updated information on the effect of the acquisition of antibiotic resistance in bacterial physiology as well as on the mechanisms that allow the compensation of the fitness costs associated with the acquisition of resistance.

Extended-Spectrum Beta-Lactamase Infections in Orthopedic-Related Devices and Prosthetic Joints

Extended-spectrum beta-lactamase-producing Enterobacteriaceae have increasingly become a public health issue in a variety of infections, including urinary tract infections and postoperative infections. The complications that occur due to these organisms in bone, joint, and prosthetic joints have not been well defined. This study reviewed the clinical characteristics, risk factors, and outcomes of patients with extended-spectrum beta-lactamase-producing Enterobacteriaceae infections of prosthetic joints or orthopedic-related hardware. Six infections met the inclusion criteria that resulted in a 100% failure rate when the hardware or prosthetic joint was not replaced initially. However, when the hardware or prosthetic joint was replaced, all of the patients did well. The use of carbapenems remains effective in these cases. [Orthopedics. 2016; 39(4):e668-e673.].

Characterization of ESBL- and AmpC-Producing and Fluoroquinolone-Resistant Enterobacteriaceae Isolated from Mouflons (Ovis orientalis musimon) in Austria and Germany

The aim of this study was to investigate the presence of β-lactamase producing or fluoroquinolone-resistant members of the family Enterobacteriaceae in European mouflons (Ovis orientalis musimon). The mouflon samples originated from nasal and perineal swabs and/or organ samples in cases of a suspected infection. Only one of the 32 mouflons was tested positive for the presence of Enterobacteriaceae that displayed either an ESBL/AmpC phenotype or were resistant to ciprofloxacin. The positively tested swab originated from a sample of the jejunal mucosa of a four-year old female mouflon. Two different colony morphotypes were identified as Escherichia coli and Klebsiella pneumoniae. These isolates were phenotypically and genotypically characterized in detail by a polyphasic approach. Both isolates were multi-drug resistant. The E. coli isolate belonged to the phylogenetic group B1 and sequence type (ST) 744 and harboured the β-lactamase genes bla_CTX-M-15 and bla_OXA-1. The K. pneumoniae, identified as ST11, harboured the β-lactamase genes bla_SHV-11, bla_OXA-1, and bla_DHA-1 as well as the plasmid-mediated quinolone resistance (PMQR) gene qnrB55. The present study demonstrates that wild animals can acquire human-derived resistance determinants and such findings may indicate environmental pollution with resistance determinants from other sources.

Pediatric extended spectrum β-lactamase infection: Community-acquired infection and treatment options

BACKGROUND

Infection caused by extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in pediatric patients has been increasing and spreading to the community, compromising the options for effective antibiotics. This retrospective study was conducted to identify which antibiotics ESBL-producing Enterobacteriaceae remain susceptible to. In addition, the prevalence of community-acquired infection caused by these organisms, and the possibility of association between these organisms and septic shock, were explored.

METHODS

Antibiotic susceptibility of ESBL-producing and non-ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from pediatric patients were reviewed to determine the rates of susceptibility to various antibiotics. A chart review was performed to clarify the prevalence of community-acquired infection and the severity.

RESULTS

Of 849 strains analyzed, 40% were ESBL positive. Apart from cephalosporins, ESBL-producing strains were also less likely to be susceptible to other antibiotics, such as quinolones, gentamicin, netilmicin, and cotrimoxazole, more than 90% of which were still susceptible to amikacin, carbapenems, colistin, and tigecycline. Around 20% of community-acquired infections in the present study were caused by ESBL-producing strains. ESBL-producing strains found in the community were more likely to be susceptible to gentamicin, netilmicin, and cefepime than those found in hospital. Infection caused by ESBL-producing strains was not significantly associated with septic shock.

CONCLUSION

The increase in infection caused by ESBL-producing Enterobacteriaceae limits the availability of effective antibiotics. Given that carbapenems are necessary for treating serious infections, amikacin, cefepime, and piperacillin/tazobactam are possible options for consolidative therapy or for non-serious infection.

Extended-Spectrum β-Lactamase- and Carbapenemase-Producing Enterobacteriaceae Isolated from Egyptian Patients with Suspected Blood Stream Infection

Objectives

The aim of the study was to investigate the prevalence of extended-spectrum β-lactamase and carbapenemase production among Enterobacteriaceae isolated from Egyptian patients with suspected blood stream infection.

Methods

Ninety-four Enterobacteriaceae blood culture isolates from Egyptian patients with suspected blood stream infection were collected, one isolate per patient. Identification of bacterial isolates was performed with MALDI-TOF (MS-based Vitek MS system, bioMerieux). Screening for ESBLs and carbapenemases production was done with the Vitek 2 system (bioMérieux). ESBL production was confirmed using the combined disk diffusion method for cefotaxime, ceftazidime, and cefepime, all with and without clavulanic acid (Rosco). Real-time PCR and sequencing were used to characterize the resistance genes. The phylogenetic groups of E. coli were identified by a PCR-based method.

Results

Of the 94 Enterobacteriaceae isolates 46 (48.93%) showed an ESBL phenotype. One Enterobacter spp isolate was ESBL-producer and meropenem-resistant. The genetic analysis showed that CTX-M was present in 89.13% (41/46) of the ESBL-producing Enterobacteriaceae, whereas TEM and SHV were detected in 56.52% (26/46) and 21.74% (10/46) respectively (47.83%) of the ESBL-producing isolates were multidrug resistant (MDR). Eleven out of 30 ESBL-producing E-coli isolates were assigned to phylogroup B2, followed by groups B1 (8 isolates), A (6 isolates) and D (5 isolates).

Conclusions

The high ESBL-E rates (48.93%) found in this study together with the identification of one carbapenem-resistant Enterobacter spp isolate is worrisome. Our results indicate that systems for monitoring and detection of ESBL-producing bacteria in Egyptian hospitals have to be established. Also strict hospital infection control policies with the restriction of the consumption of extended-spectrum cephalosporins are necessary.

Mini-review: Epidemiology and zoonotic potential of multiresistant bacteria and Clostridium difficile in livestock and food

AIM

Information on the epidemiology of multiresistant bacteria (MRB) with zoonotic potential is growing but still remains quite incomplete. This narrative mini-review provides a general overview of the epidemiology of the most important zoonotic MRB in cattle, swine and poultry in Europe.

METHODS

A literature search was conducted mainly on the PubMed website including articles published until April 2012.

RESULTS

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) especially poses a zoonotic risk to people working in close contact with livestock. These people may become carriers themselves and the hazard of transmission into health-care facilities needs surveillance. Extended-spectrum beta-lactamases (ESBL) producing bacteria are widely spread in both humans and livestock, sharing similar genotypes, especially of the CTX-M-group, which makes a zoonotic transfer very likely. Identical strains of vancomycin-resistant enterococci (VRE) were found both in humans and animals, after ingestion of animal strains transient colonization of the human gut may be possible. Only a few data are available on the transmission of methicillin-resistant coagulase-negative staphylococci (MR-CoNS) between humans and animals. Direct contact to colonized animals may be a risk factor as well as the exchange of resistance genes between human and animal staphylococci. Clostridium difficile (C. difficile) ribotype 078 emerges in livestock and humans and a zoonotic transmission seems probable as genotypes and diseases resemble each other.

CONCLUSION

All discussed MRB and C. difficile are important nosocomial agents which also occur in livestock and were found in foods of animal origin. Further analysis is needed to reveal the exact transmission routes and to perform a reliable risk assessment.

Sensitization of intracellular Salmonella enterica serovar Typhimurium to aminoglycosides in vitro and in vivo by a host-targeted antimicrobial agent

Aminoglycosides exhibit relatively poor activity against intracellular Salmonella enterica serovar Typhimurium due to their low permeativity across eukaryotic cell membranes. Previously, we identified the unique ability of AR-12, a celecoxib-derived small-molecule agent, to eradicate intracellular Salmonella Typhimurium in macrophages by facilitating autophagosome formation and suppressing Akt kinase signaling. In light of this unique mode of antibacterial action, we investigated the ability of AR-12 to sensitize intracellular Salmonella to aminoglycosides in macrophages and in an animal model. The antibacterial activities of AR-12 combined with various aminoglycosides, including streptomycin, kanamycin, gentamicin, and amikacin, against intracellular S. Typhimurium in murine RAW264.7 macrophages were assessed. Cells were infected with S. Typhimurium followed by treatment with AR-12 or individual aminoglycosides or with combinations for 24 h. The in vivo efficacies of AR-12, alone or in combination with gentamicin or amikacin, were also assessed by treating S. Typhimurium-infected BALB/c mice daily for 14 consecutive days. Exposure of S. Typhimurium-infected RAW264.7 cells to a combination of AR-12 with individual aminoglycosides led to a reduction in bacterial survival (P < 0.05), both intracellular and extracellular, that was greater than that seen with the aminoglycosides alone. This sensitizing effect, however, was not associated with increased aminoglycoside penetration into bacteria or macrophages. Moreover, daily intraperitoneal injection of AR-12 at 0.1 mg/kg of body weight significantly increased the in vivo efficacy of gentamicin and amikacin in prolonging the survival of S. Typhimurium-infected mice. These findings indicate that the unique ability of AR-12 to enhance the in vivo efficacy of aminoglycosides might have translational potential for efforts to develop novel strategies for the treatment of salmonellosis.

Fecal carriage of extended-spectrum β-lactamases and AmpC-producing Escherichia coli in a Libyan community

Background

Extended-spectrum β-lactamases (ESBLs), including the AmpC type, are important mechanisms of resistance among Enterobacteriaeceae. CTX-M type extended-spectrum β- lactamases, of which there are now over 90 variants, are distributed globally, yet appear to vary in regional distribution. AmpC β-lactamases hydrolyze third generation cephalosporins, but are resistant to inhibition by clavulanate or other β-lactamase inhibitors in vitro. Fecal carriage and rates of colonization by bacteria harboring these resistance mechanisms have been reported in patients with community-acquired infections and in healthy members of their households. Expression of these ESBLs compromises the efficacy of current antibacterial therapies, potentially increasing the seriousness of hospital- and community-acquired Escherichia coli (E. coli) infections.

To investigate the occurrence of ESBL-producing E. coli in human fecal flora isolated from two pediatric populations residing in the Libyan cities Zleiten and Abou El Khoms. Isolates were further studied to characterize genes encoding β-lactam resistance, and establish genetic relationships.

Methods

Antibiotic resistance profiles of phenotypically characterized E. coli isolates recovered from the stools of 243 Libyan children during two surveillance periods in 2001 and 2007 were determined by the disk diffusion method. ESBL-screening was performed using the cephalosporin/clavulanate double synergy disc method, and the AmpC-phenotype was confirmed by the aminophenyl-boronic acid test. ESBL genes were molecularly characterized. Phylogenetic group and multilocus sequence typing (MLST) were determined for ESBL-producing isolates and PFGE was performed to compare banding profiles of some dominant strains.

Results

ESBLs were identified in 13.4% (18/134) of E. coli isolates, and nine isolates (6.7%) demonstrated AmpC activity; all 18 isolates contained a CTX-M gene. Three CTX-M gene families (CTX-M-1, n = 9; CTX-M-15, n = 8 and CTX-M-3, n = 1) were distributed in diverse E. coli backgrounds (phylogenetic group D, 39%; B2, 28%; B1, 22% and A, 11%). MLST analysis revealed 14 sequence type (ST) with six new sequence types. The gene encoding the CMY-2 enzyme was detected in five AmpC-positive E. coli.

Conclusions

These results identified heterogeneous clones of CTX-M-producing E. coli in the fecal isolates, indicating that the intestinal tract acts as a reservoir for ESBL-producing organisms, and a trafficker of antibiotic resistance genes.

Isolation and characterization of multidrug-resistant bacteria from minced meat in Austria

INTRODUCTION

Resistant bacteria are a well-known public health problem. This study was conducted to investigate the prevalence and genetic characteristics of extended spectrum β-lactamase (ESBL) producing enterobacteria, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) in mixed minced meat from pork and beef.

METHODS

One hundred samples of mixed minced meat were collected from supermarkets (n = 70) and local butcher shops (n = 30) in the city of Graz (Austria). After enrichment and inoculation on selective media, bacteria were identified with MALDI-TOF MS or Vitek2 systems, tested for antibiotic resistance and further characterized with PCR and sequencing.

RESULTS

In 20 of the 100 meat samples 24 ESBL positive Escherichia coli isolates were found. The most common ESBL among the isolates was CTX-M-1. Other detected bla genes contained CTX-M-14, CTX-M-32, SHV-12 and TEM-52 types. Nine samples were tested positive for MRSA and spa-typed. Detected spa-types were hospital-acquired t3928, as well as livestock-associated t011, t034 and t2241. No VRE were found.

CONCLUSION

A contamination of meat with ESBL-producing E. coli and MRSA was confirmed in this study. The large diversity of ESBL producing E. coli could indicate a growing dissemination of ESBL genes in E. coli found in meat products from porcine and bovine origin.

Phenotypic and genotypic evaluation of beta-lactamases (ESBL and KPC) among enterobacteria isolated from community-acquired monomicrobial urinary tract infections

Beta-lactamases enzymes such as extended-spectrum beta-lactamases (ESBL) and carbapenemase type beta-lactamases (KPC) confer resistance to beta-lactam drugs among Gram-negative rods, mainly Enterobacteriaceae, as those frequently related to urinary tract infections (UTI). The aim of this study was to evaluate ESBL and KPC among enterobacteria isolated from monomicrobial UTI and to establish correlations between the presence of genetic markers and the phenotypic resistance to beta-lactam antibiotics. Out of 12 304 urine samples collected during 2009, 93 enterobacteria showing an ESBL phenotype were recovered. Imipenem was used for KPC screening and modified disk approximation assay was used for detection of ESBL phenotype. Polymerase chain reaction was used for screening of bla(SHV), bla(TEM), bla(CTX-M), and bla(KPC). Considering the isolated bacteria showing ESBL phenotype 56% of the isolates were positive for two genes. The bla(TEM) was the most frequent (87·1%). Neither KPC phenotype nor bla(KPC)-harboring bacteria were observed. Monitoring the antimicrobial resistance is extremely important to sustain empirical therapy of community-acquired urinary tract infections (Co-UTI).

Rapid detection of β-lactamase-hydrolyzing extended-spectrum cephalosporins in Enterobacteriaceae by use of the new chromogenic βLacta test

The chromogenic βLacta test developed for the rapid detection of β-lactamase-hydrolyzing extended-spectrum cephalosporins in Enterobacteriaceae revealed good performance with extended-spectrum β-lactamase (ESBL) producers (97.5% true-positive results). However, false-negative results occurred with chromosomal AmpC hyperproducers and plasmid AmpC producers, whereas uninterpretable results were mostly due to VIM-1 carbapenemase producers and possibly low levels of expressed ESBLs.

Determination of susceptibility to fosfomycin and tigecycline of Enterobacteriaceae, particularly Escherichia coli isolates, producing extended-spectrum β-lactamases from multiple regional Canadian hospitals

BACKGROUND

The worldwide spread of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, particularly Escherichia coli, has significantly limited therapeutic options, especially for urinary tract infections. Although limited in their indications, fosfomycin and tigecycline are potential agents to treat infections due to ESBL-producing organisms. Although not routinely performed, susceptibility testing to both is necessary to ensure there is not an increase in resistance.

METHODS

A total of 160 isolates of ESBL-producing E coli were isolated from patients at multiple regional hospitals in the Interior Health Region of British Columbia from June 2009 to January 2012. Isolates were obtained from various body fluids and sites including urine (78.2%), wounds, blood, gall bladder drain and respiratory specimens. All isolates were tested using the E-test method (Etest, bioMérieux, France) for tigecycline and Kirby Bauer disk diffusion method for fosfomycin using European Committee of Antimicrobial Susceptibility Testing breakpoints for tigecycline and Clinical and Laboratory Standards Institute zone sizes for fosfomycin.

RESULTS

All 160 isolates were found to be susceptible to tigecycline, while five isolates (3.1%) were resistant to fosfomycin (four resistant, one intermediate).

CONCLUSION

Although resistance to these antibiotics has previously been reported, the present study confirmed that isolates of ESBL-producing E coli from the Interior Health Region of British Columbia remain highly susceptible to both tigecycline and fosfomycin.

Prevalence and Genotypic Characterization of Extended-Spectrum Beta-Lactamases Produced by Gram Negative Bacilli at a Tertiary Care Hospital in Rural South Western Uganda

AIM

To determine the prevalence and genotypic characterisation of extended spectrum beta-lactamases produced by gram negative bacilli isolated at Mbarara Regional Referral Hospital (MRRH).

SAMPLES

Gram negative clinical isolates.

STUDY DESIGN

Laboratory-based descriptive cross-sectional study.

PLACE AND DURATION OF THE STUDY

MRRH, June and August 2012.

METHODS

Gram negative clinical isolates were sub cultured, and identified using biochemical tests. They were screened for ESBL by using oxyimino-cephalosporins and confirmed by double disc synergy Genotyping was performed using the PCR for TEM, SHV and CTX-M. Susceptibility pattern for the extended spectrum beta-lactamases, (ESBL) - positive isolates to other antibiotic classes was performed by the Kirby Bauer Technique.

RESULTS

A total of 484 isolates were included in the study. The commonest ESBL producers were Escherichia coli (34%), followed by unidentified coliforms (19.3%) and Klebsiella spp. (12.7%). Phenotypically, 88/484 were ESBL producers while genotypically 213/ 484 possessed ESBL genes. The ESBL genes were bla_CTX-M (146; 70%), bla_SHV (72; 34%) and bla_TEM (100; 47%). 87of 213 isolates expressed more than one ESBL gene. Of these 36 (7.4%) produced bla_CTX-M/bla_SHV, 28 (5.8%) blaCTX-M /blaTEM, 4 (0.8%) blaSHV/ blaTEM and 19 (3.9%) blaCTX-M/blaSHV/blaTEM. Sixty two (16%) were phenotypically and genotypically positive, 12 (3%) of the isolates were phenotypically positive but genotypically negative and 140 (37%) isolates were phenotypically negative but genotypically positive. The ESBL producers were highly susceptible to imipenem (95%), nitrofurantoin (66%) but less susceptible to ampicillin (4%) and ticarcillin (7%).

CONCLUSION

ESBL production among the Gram-negative clinical isolates at MRRH is very high with several isolates possessing multiple genes. The ESBL producers are highly susceptible to imipenem, but very resistant to ciprofloxacin.

Co-resistance to different classes of antibiotics among ESBL-producers from aquatic systems

In this study we investigated the co-occurrence of resistance to non-beta-lactams among cefotaxime-resistant extended-spectrum beta-lactamase (ESBL) producers (ESBL(+)) versus non-ESBL producers (ESBL(-)), from aquatic environments. Higher prevalence of resistance to tetracycline, fluoroquinolones and aminoglycosides were observed in ESBL(+). Among ESBL(+) resistant to tetracycline (n = 18), tet(A) was detected in 88.9% and tet(B) in 16.7%. Among fluoroquinolone-resistant-ESBL(+) (n = 15), aacA4-cr and qnrVC4 were identified in 26.6% and 40% strains, respectively. The qnrVC4 gene was detected for the first time in Pseudomonas sp. and Escherichia coli. Class 1 integrase genes were detected in 56.41% of ESBL(+) and in 27.67% ESBL(-). Gene cassette arrays identified conferred resistance to aminoglycosides (aadA-type genes and aacA4), trimethoprim (dfrA17), chloramphenicol (catB8), fluoroquinolones (qnrVC4) and beta-lactams (blaOXA-10). Conjugation experiments were performed with CTX-M-producers. Transconjugants showed multiresistance to 3 or more classes of antibiotics, and conjugative plasmids were assigned to IncF, IncK and IncI1 replicons. Results obtained showed that co-selection of resistance to aminoglycosides, quinolones and tetracyclines is prevalent among ESBL-producers and that these features are successfully mobilized by IncF, IncK and IncI1 conjugative plasmids. This study reinforces the importance of natural aquatic systems as reservoir of mobile genetic platforms carrying multiple resistance determinants. Moreover, to the best of our knowledge, this constitutes the first observation of IncK::CTX-M-3 in Aeromonas hydrophila and the first report of IncK plasmids in Portugal.