Cefotaxime-resistant Isolates Research Articles

Comparison of methods proposed for monitoring cefotaxime-resistant Escherichia coli in the water environment.

Escherichia coli is a promising subject for globally coordinated surveillance of antimicrobial resistance (AMR) in water environments due to its clinical relevance and widespread use as an indicator of fecal contamination. Cefotaxime-resistant E. coli was recently evaluated favorably for this purpose by the World Health Organization TriCycle Protocol, which specifies tryptone bile x-glucuronide (TBX) medium and incubation at 35°C. We assessed comparability with the U.S. Environmental Protection Agency-approved method for E. coli quantification, which uses membrane-thermotolerant E. coli (mTEC) agar and incubation at 44.5°C, in terms of recovery of E. coli and cefotaxime-resistant E. coli from wastewater influent and surface waters. Total E. coli concentrations in wastewater influent were 106-108 CFU/100 mL, while cefotaxime-resistant E. coli were ~100-fold lower. Total E. coli in surface waters were ~102 CFU/100 mL, and cefotaxime-resistant isolates were near the limit of detection (0.4 CFU/100 mL). Total and putative cefotaxime-resistant E. coli concentrations did not differ significantly between media or by incubation method; however, colonies isolated on mTEC were more frequently confirmed to species (97.1%) compared to those from TBX (92.5%). Incubation in a water bath at 44.5°C significantly decreased non-specific background growth and improved confirmation frequency on both media (97.4%) compared to incubation at 35°C (92.3%). This study helps to advance globally coordinated AMR in water environments and suggests that the TriCycle Protocol is adaptable to other standard methods that may be required in different locales, while also offering a means to improve specificity by decreasing the frequency of false-positive identification of cefotaxime-resistant E. coli by modifying incubation conditions.IMPORTANCEAs antibiotic-resistant bacteria in water environments are increasingly recognized as contributors to the global antibiotic resistance crisis, the need for a monitoring subject that captures antibiotic resistance trends on a global scale increases. The World Health Organization TriCycle Protocol proposes the use of cefotaxime-resistant Escherichia coli isolated on tryptone bile x-glucuronide agar. The U.S. Environmental Protection Agency (USEPA) criteria for safe recreational waters also use E. coli as an indicator but specify the use of mTEC agar at a higher incubation temperature (44.5°C vs 35°C). We assessed the comparability of these methods for isolating total and cefotaxime-resistant E. coli, finding overall good agreement and performance, but significantly higher specificity toward E. coli selection with the use of the USEPA incubation protocol and mTEC agar. This study is the first to directly compare these methods and provides evidence that the methods may be used interchangeably for global surveillance of antibiotic resistance in the environment.

Prevalence and molecular characterization of cefotaxime-resistant Salmonella strains recovered from retail meat samples in Shenzhen, China, during 2014-2017.

In this work, we collected foodborne Salmonella strains in Shenzhen, China, during 2014-2017 and investigated the genetic profile of all cefotaxime-resistant isolates in the collection. The strains were subjected to antimicrobial susceptibility tests, whole-genome sequencing, bioinformatics analysis, and conjugation studies. A total of 79 cefotaxime-resistant Salmonella were identified and found to exhibit multidrug resistance. Resistance rate recorded during the study period increased from 1.9% to 9.1%. Salmonella Typhimurium was the predominant serovar, and CTX-M family genes were dominant among the ESBLs genes detected. Notably, CTX-M-bearing plasmids or transposons often contain other drug resistance genes. Furthermore, a combination of CTX-M-55 and CTX-M-65 genes was detected for the first time in foodborne Salmonella strains. Our findings reveal the prevalence and molecular characteristics of cefotaxime-resistant foodborne Salmonella strains in southern China. IMPORTANCE Cefotaxime-resistant Salmonella strains pose an increasing threat to human health by causing infections with limited treatment options. It is therefore necessary to undertake a surveillance on the prevalence of such strains and investigate the resistance and transmission mechanisms. In this work, various ESBL genes flanked by different IS located in different mobile genetic elements were detectable among cefotaxime-resistant Salmonella strains. These data show that the high prevalence and genotypic diversity of cefotaxime-resistant foodborne Salmonella strains in China are possibly attributed to the evolution and transmission of a wide range of multidrug resistance-encoding mobile genetic elements.

Penicillin and Cefotaxime Resistance of Quinolone-Resistant Neisseria meningitidis Clonal Complex 4821, Shanghai, China, 1965-2020.

Clonal complex 4821 (CC4821) Neisseria meningitidis, usually resistant to quinolones but susceptible to penicillin and third-generation cephalosporins, is increasing worldwide. To characterize the penicillin-nonsusceptible (PenNS) meningococci, we analyzed 491 meningococci and 724 commensal Neisseria isolates in Shanghai, China, during 1965-2020. The PenNS proportion increased from 0.3% in 1965-1985 to 7.0% in 2005-2014 and to 33.3% in 2015-2020. Of the 26 PenNS meningococci, 11 (42.3%) belonged to the CC4821 cluster; all possessed mutations in penicillin-binding protein 2, mostly from commensal Neisseria. Genetic analyses and transformation identified potential donors of 6 penA alleles. Three PenNS meningococci were resistant to cefotaxime, 2 within the CC4821 cluster. With 96% of the PenNS meningococci beyond the coverage of scheduled vaccination and the cefotaxime-resistant isolates all from toddlers, quinolone-resistant CC4821 has acquired penicillin and cefotaxime resistance closely related to the internationally disseminated ceftriaxone-resistant gonococcal FC428 clone, posing a greater threat especially to young children.

Interrelationship of Extended Spectrum Beta-Lactamase Producers and Biofilm Formation among the Gram-Negative Bacteria from Tabuk, KSA

AIM: The present study investigates the production of extended-spectrum beta-lactamases (ESBL) and the formation of biofilm among different bacterial pathogens. METHODS: The study conducted prospective analysis on bacteria isolates (Gram-negative) from patients who have diagnosed with infections with bacteria between October 2020 and January 2022. RESULTS: The results showed that there were 53 biofilm producers in Escherichia coli. In contrast, Pseudomonas aeruginosa was observed to have the highest percentage, with 32/40 (80%) isolates being biofilm producers. The least number of isolates were Morganella morganii (n = 2) with two (100%) biofilm producers. The resistance in the biofilm positive isolates was high compared with biofilm negative. About 88% of phenotypic ESBL-positive isolates were biofilm producers, and 97% of cefotaxime-resistant biofilm-positive isolates were genotypic positive for CTX-M, TEM, and SHV genes. CONCLUSION: The present study has shown that protection against antibiotics through mucus production is possible due to bacteria’s reduced metabolic activity and diffusion of antibiotics across the biofilm matrix. In this study, all the bacterial strains of E. coli and Klebsiella pneumoniae were reported to be MDR and competent for establishing biofilm.

Antimicrobial resistance profiles of Campylobacter jejuni and Salmonella spp. isolated from enteritis patients in Japan.

Understanding the antimicrobial resistance of Campylobacter jejuni and Salmonella spp. isolated from patients with enteritis will aid in therapeutic decision-making. This study aimed to characterize C. jejuni and Salmonella spp. isolates from patients with enteritis. For C. jejuni, the resistance rates against ampicillin, tetracycline, and ciprofloxacin were 17.2%, 23.8%, and 46.4%, respectively. All the C. jejuni isolates were susceptible to erythromycin, which is recommended as a first-choice antimicrobial if Campylobacter enteritis is strongly suspected. C. jejuni was classified into 64 sequence types (STs), and the five major STs were ST22, ST354, ST21, ST918, and ST50. The ciprofloxacin-resistance rate of ST22 was 85.7%. For Salmonella, the resistance rates against ampicillin, cefotaxime, streptomycin, kanamycin, tetracycline, and nalidixic acid were 14.7%, 2.0%, 57.8%, 10.8%, 16.7%, and 11.8%, respectively. All the Salmonella spp. isolates were susceptible to ciprofloxacin. Therefore, fluoroquinolones are the recommended antimicrobials against Salmonella enteritis. S. Thompson, S. Enteritidis, and S. Schwarzengrund were the three most prevalent serotypes. The two cefotaxime-resistant isolates were serotyped as S. Typhimurium and were found to harbor blaCMY-2. The results of this study would help select antimicrobials for treating patients with Campylobacter and Salmonella enteritis.

RESISTANCE OF KLEBSIELLA PNEUMONIAE TO ANTIBIOTICS OF CAT TREATED AT ANIMAL CLINIC

The antibiotic resistance of Klebsiella pneumoniae has become a global health concern, leading in a reduction in the efficacy of various medications. This study seeks to determine the antibiotic resistance of K. pneumoniae isolated from cats hospitalized in Depok veterinary clinics. Surveys, sample collection, isolation, identification, and antibiotic susceptibility testing comprised the research technique. Seven K. pneumoniae isolates were discovered. There were seven cefotaxime resistant isolates, three amoxicillin resistant isolates, one gentamicin resistant isolate, and one enrofloxacin resistant strain. At the same concentration, one isolate shown intermediate susceptibility to amoxicillin, enrofloxacin, and doxycycline. Sensitivity was demonstrated by six gentamicin isolates, six doxycycline isolates, five enrofloxacin isolates, and three amoxicillin isolates. This information should help veterinarians choose the best efficient antibiotic to treat infections caused by these bacteria.

Genetic heterogeneity and predominance of blaCTX-M -15 in cefotaxime-resistant Enterobacteriaceae isolates colonizing hospitalized children in Tunisia.

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae have emerged as important nosocomial pathogens. Community infections by these organisms have been also reported and were associated with previous intestinal colonization. We aimed to characterize cefotaxime-resistant Enterobacteriaceae (CTX-R-En) isolated from hospitalized children in a Tunisian paediatric ward. Seventy CTX-R-En isolates were collected from 227 rectal swabs from hospitalized children in a paediatric ward. Antimicrobial susceptibility testing was determined according to the EUCAST guidelines. Isolates were characterized by polymerase chain reaction (PCR, genes encoding: ESBLs, pAmpC, carbapenemases, plasmid-mediated quinolone resistance, virulence factors in Escherichia coli and Klebsiella pneumoniae isolates, occurrence of classes 1 and 2 integrons, phylogenetic groups of E.coli isolates, ERIC-PCR and PCR-based replicon typing) and conjugal transfer experiments. In total, 65 out of 227 (28·6%) hospitalized children were colonized with CTX-M-R-En, and 70 isolates were identified. Isolates were 59 ESBL-, 7 plasmidic-AmpC (pAmpC)-, 3 ESBL+pAmpC-, and one ESBL+carbapenemase producers. The following bla genes were identified: blaCTX-M-15 (n = 54), blaCTX-M-1 (n = 5), blaCTX-M-9 (n = 2), blaCTX-M-13 (n = 1) and blaCTX-M-14 (n = 1), blaCMY-2 (n = 5), blaCMY-4 (n = 4), blaACC-1 (n = 1) and blaOXA-48 (n = 1). Our results showed that hospitalized children were colonized with various CTX-R-En-producing several beta-lactamase enzymes.

Molecular characterization of extended-spectrum cephalosporin and fluoroquinolone resistance genes in Salmonella and Shigella isolated from clinical specimens in Thailand

Antimicrobial resistance of Salmonella and Shigella has become a major clinical and public health problem. The incident of co-resistance to third generation cephalosporins and fluoroquinolone is a serious therapeutic issue in Thailand. The present study aimed to investigate the antimicrobial resistance and molecular character of clinical Shigella and Salmonella isolates. A total of 33 Salmonella and 53 Shigella cefotaxime-resistant isolates were collected from human clinical cases in Thailand during the period from 2011–2018. The antimicrobial susceptibility of Salmonella and Shigella was determined by the disk diffusion method, and extended-spectrum beta-lactamase (ESBL) production was characterized by the double-disk synergy test. Genotype characterization was performed by PCR and DNA sequencing. Thirty-two (97.0%) and fifty-two (98.1%) isolates of cefotaxime-resistant Salmonella and Shigella, respectively, were identified as ESBL producers. Shigella sonnei (4 isolates), Salmonella serovar 4,5,12:i:- (6 isolates), Salmonella serovar Agona (2 isolates) and Salmonella serovar Rissen (2 isolates) showed co-resistance to ciprofloxacin and cefotaxime or ceftriaxone. The combination of blaCTX-M-15 plus other ESBL and/or AmpC β-lactamase genes was the most dominant of the genotype patterns in ESBL-producing isolates. The plasmid harbouring the aac(6′)-Ib-cr gene and mutations of gyrA (S83F, D87Y or D87G) and parC (T57S) genes was found in 2 ESBL-producing Salmonella isolates. Three Shigella sonnei isolates harboured mutations in gyrA (S83L, D87Y or D87G), and only one Shigella sonnei phase I isolate showed mutations in both gyrA (S83L and D87G) and parC (S80I) genes. Among these clinical Shigella sonnei isolates, qnrS determinants were identified. Production of ESBLs is an important mechanism for resistance to extended-spectrum cephalosporins in Salmonella and Shigella. The emergence of a decreased susceptibility to extended-spectrum cephalosporins and fluoroquinolone in ESBL-producing isolates has important clinical and therapeutic implications.

Dissemination of High-Risk Clones Enterobacterales among Bulgarian Fecal Carriage Isolates

The gastrointestinal tract is an important reservoir of high-risk Enterobacteria clones and a driver of antimicrobial resistance in hospitals. In this study, patients from six hospitals in four major Bulgarian towns were included in this study. Overall, 205 cefotaxime-resistant isolates (35.3%) of Enterobacterales order were detected in fecal samples among 580 patients during the period of 2017-2019. ESBL/carbapenemase/plasmidic AmpC producer rates were 28.8%, 2.4%, and 1.2%, respectively. A wide variety of ESBLs: CTX-M-15 (41%), CTX-M-3 (24%), CTX-M-27 (11%), and CTX-M-14 (4%) was found. The carbapenemases identified in this study were New Delhi metalo-β-lactamase (NDM)-1 (5.4%) and Klebsiella carbapenemase (KPC)-2 (1.5%). Most NDM-1 isolates also produced CTX-M-15/-3 and CMY-4 β-lactamases. They belonged to ST11 Klebsiella pneumoniae clone. The epidemiology typing revealed three main high-risk K. pneumoniae clones (26%)-ST11, ST258, and ST15 and five main Escherichia coli clones-ST131 (41.7%), ST38, ST95, ST405, and ST69. Sixty-one percent of ST131 isolates were from the highly virulent epidemic clone O25b:H4-ST131. Phylotyping revealed that 69% of E. coli isolates belonged to the virulent B2 and D groups. Almost all (15/16) Enterobacter isolates were identified as E. hormaechei and the most common ST type was ST90. Among all of the isolates, a high ESBL/carbapenemases/plasmid AmpC (32.4%) prevalence was observed. A significant proportion of the isolates (37%) were members of high-risk clones including two pan-drug-resistant K. pneumoniae ST11 NDM-1 producing isolates. Due to extensive antibiotic usage during COVID-19, the situation may worsen, so routine screenings and strict infection control measures should be widely implemented.

CTX-M-Producing Bacteria Isolated from a Highly Polluted River System in Portugal.

Enterobacteriaceae resistant to third-generation cephalosporins are a great concern for public health, as these are first-line drugs to treat infections. The production of carbapenemases and extended spectrum beta-lactamases (ESBLs) and/or the overexpression of AmpC β-lactamases are the main mechanisms of resistance to these antibiotics. Among the ESBLs, CTX-M β-lactamases are the most prevalent worldwide. Our aims were to determine the prevalence of cefotaxime-resistant Enterobacteriaceae along a heavily polluted river and characterize blaCTX-M carriers. River water was collected in 11 sites along the main course and tributaries, in two sampling moments. Water quality was evaluated and a collection of cefotaxime-resistant isolates was obtained. blaCTX-M carriers were characterized regarding phylogenetic affiliation, clonality, antibiotic susceptibility, gene diversity, and context. Water presented very low quality in all sites. From 147 cefotaxime-resistant isolates, 46% carried blaCTX-M and were affiliated with Escherichia, Klebsiella, Enterobacter, and Citrobacter. Molecular typing revealed clonal isolates in different sites and over the two years, suggesting survival of the strains in the river or continuous pollution inputs from the same sources. Eight variants of blaCTX-M were found, with blaCTX-M-15 being the most prevalent (52.5%). Sites with a lower water quality showed the highest resistance rates and prevalence of blaCTX-M, suggesting that river water may embody human health risks.

Lineages, Virulence Gene Associated and Integrons among Extended Spectrum β-Lactamase (ESBL) and CMY-2 Producing Enterobacteriaceae from Bovine Mastitis, in Tunisia.

Extended Spectrum Beta-Lactamase (ESBL) Enterobacteriaceae are becoming widespread enzymes in food-producing animals worldwide. Escherichia coli and Klebseilla pneumoniae are two of the most significant pathogens causing mastitis. Our study focused on the characterization of the genetic support of ESBL/pAmpC and antibiotic resistance mechanisms in cefotaxime-resistant (CTXR) and susceptible (CTXS) Enterobacteriaceae isolates, recovered from bovine mastitis in Tunisia, as well as the analyses of their clonal lineage and virulence-associated genes. The study was carried out on 17 ESBL/pAmpC E. coli and K. pneumoniae and 50 CTXS E. coli. Detection of resistance genes and clonal diversity was performed by PCR amplification and sequencing. The following β-lactamase genes were detected: blaCTX-M-15 (n = 6), blaCTX-M-15 + blaOXA-1 (2), bla CTX-M-15 + blaOXA-1 + blaTEM-1b (2), blaCTX-M-15 + blaTEM-1b (4), blaCMY-2 (3). The MLST showed the following STs: ST405 (n = 4 strains); ST58 (n = 3); ST155 (n = 3); ST471 (n = 2); and ST101 (n = 2). ST399 (n = 1) and ST617 (n = 1) were identified in p(AmpC) E. coli producer strains. The phylogroups A and B1 were the most detected ones, followed by the pathogenic phylogroup B2 that harbored the shigatoxin genes stx1/stx2, associated with the cnf, fimA, and aer virulence factors. The qnrA/qnrB, aac(6′)-Ib-cr genes and integrons class 1 with different gene cassettes were detected amongst these CTXR/S isolated strains. The presence of different genetic lineages, associated with resistance and virulence genes in pathogenic bacteria in dairy farms, may complicate antibiotic therapies and pose a potential risk to public health.

Insights and genetic features of extended-spectrum beta-lactamase producing Escherichia coli isolates from two hospitals in Ghana

Recently, the emergence and rapid dissemination of extended-spectrum beta-lactamase (ESBL)-producing bacteria, particularly of the family Enterobacteriaceae, has posed serious healthcare challenges. Here, we determined the antimicrobial susceptibility and genetic characteristics of 164 Escherichia coli strains isolated from infected patients in two hospitals in Ghana. In total, 102 cefotaxime-resistant isolates (62.2%) were identified as ESBL-producers. Multilocus sequence typing of the ESBL-producers identified 20 different sequence types (STs) with ST131 (n = 25, 24.5%) as the dominant group. Other detected STs included ST410 (n = 21, 20.6%) and ST617 (n = 19, 18.6%). All identified ESBL-producers harbored blaCTX-M-14, blaCTX-M-15, or blaCTX-M-27, with blaCTX-M-15 (n = 96, 94.1%) being the most predominant ESBL allele. Further analysis showed that the immediate genetic environment around blaCTX-M-15 is conserved within blaCTX-M-15 containing strains. Five of the 25 ST131 isolates were clustered with clade A, one with sub-clade C1, and 19 with the dominant sub-clade C2. The results show that fluoroquinolone-resistant, blaCTX-M-14- and blaCTX- M-15-producing ESBL E. coli ST131 strains belonging to clade A and sub-clades C1 and C2 are disseminating in Ghanaian hospitals. To the best of our knowledge, this is the first report of the ST131 phylogeny in Ghana.

Detection and characterisation of extended-spectrum and plasmid-mediated AmpC β-lactamase produced by Escherichia coli isolates found at poultry farms in Bosnia and Herzegovina.

Extended-spectrum β-lactamases (ESBLs) hydrolyse extended-spectrum cephalosporins (ESC) and aztreonam. As ESBL-producing organisms have been identified in food producing animals, the aim of our study was to detect and analyse such Escherichia coli isolates from poultry. Antibiotic susceptibility of the isolates was determined with disk-diffusion and broth microdilution methods. ESBLs were detected with the double-disk synergy and inhibitor-based test with clavulanic acid. The transferability of cefotaxime resistance was determined with conjugation experiments, and genes encoding ESBLs, plasmid-mediated AmpC β-lactamases, and quinolone resistance determinants identified by polymerase chain reaction. The study included 108 faecal samples (cloacal swabs) from 25 different poultry farms in the Zenica-Doboj Canton, Bosnia and Herzegovina. Of these, 75 (69.4 %) were positive for E. coli, of which 27 were resistant to cefotaxime, amoxicillin, cefazoline, and cefriaxone, and susceptible to imipenem, meropenem, ertapenem, and amikacin. All 27 cefotaxime-resistant isolates were positive in double-disk synergy and combined disk tests. Eighteen isolates transferred cefotaxime resistance to E. coli recipient. Twenty-one isolates were positive for the blaCTX-M-1 cluster genes and seven for blaCTX-M-15. Fourteen were positive for the blaTEM genes. The most frequent plasmid incompatibility group was IncFIB, whereas IncFIA and Inc HI1 were present in only a few isolates. Two different sequence types (STs) were identified: ST117 and ST155. The emergence of ESBL-producing E. coli in farm animals presents a public health threat, as they can colonise the intestine and cause infections in humans.

Isolation of Human Lineage, Fluoroquinolone-Resistant and Extended-β-Lactamase-Producing Escherichia coli Isolates from Companion Animals in Japan.

An increase in human and veterinary fluoroquinolone-resistant Escherichia coli is a global concern. In this study, we isolated fluoroquinolone-resistant E. coli isolates from companion animals and characterized them using molecular epidemiological analysis, multiplex polymerase chain reaction to detect E. coli ST131 and CTX-M type extended-spectrum β-lactamases (ESBL), and multi-locus sequence typing analysis. Using plain-CHROMagar ECC, 101 E. coli isolates were isolated from 34 rectal swabs of dogs and cats. The prevalence of resistance to fluoroquinolone and cefotaxime was 27.7% and 24.8%, respectively. The prevalence of fluoroquinolone-resistant isolates (89.3%) was higher when CHROMagar ECC with CHROMagar ESBL supplement was used for E. coli isolation. The prevalence of cefotaxime resistance was also higher (76.1%) when 1 mg/L of ciprofloxacin-containing CHROMagar ECC was used for isolation. The cefotaxime-resistant isolates possessed CTX-M type β-lactamase genes (CTX-M-14, CTX-M-15, or CTX-M-27). Seventy-five percent of fluoroquinolone-resistant isolates were sequence types ST131, ST10, ST1193, ST38, or ST648, which are associated with extensive spread in human clinical settings. In addition, we isolated three common fluoroquinolone-resistant E. coli lineages (ST131 clade C1-M-27, C1-nM27 and ST2380) from dogs and their respective owners. These observations suggest that companion animals can harbor fluoroquinolone-resistant and/or ESBL-producing E. coli, in their rectums, and that transmission of these isolates to their owners can occur.

Resistance profiles and diversity of β-lactamases in Escherichia coli strains isolated from city-scale sewage surveillance in Bergen, Norway mimic clinical prevalence

The aim of this study was to examine antibiotic resistance profiles and diversity of β-lactamases in Escherichia coli present within the population and the potential spread of resistant E. coli into the receiving environment using city-scale sewage surveillance. In E. coli isolates from ECC plates without antibiotics from ten influent samples (n = 300), highest resistance was observed against ampicillin (16.6%), sulfamethoxazole (9.7%) and trimethoprim (9.0%), while in effluent samples (n = 262) it was against sulfamethoxazole (11.8%), ampicillin (11.5%) and tetracycline (8.8%). All isolates (n = 123) obtained on cefotaxime-containing plates were multidrug-resistant. Several clinically important antibiotic resistance genes (ARGs) were detected in 46 E. coli isolates subjected to whole-genome sequencing, including carbapenemases like NDM-6, VIM-1 and OXA-48-variant, as well as tigecycline resistance gene tet(X4). CTX-M-15 was the most prevalent (42.9%) extended-spectrum β-lactamase among cefotaxime-resistant isolates, followed by CTX-M-27 (31.4%) and CTX-M-14 (17.1%), resembling clinical prevalence in Norway. Most of the sequenced isolates carried other clinically relevant ARGs, such as dfrA17, sul1, sul2, tet(A), aph(6)-Id, aph(3’’)-Ib and aadA5. Sixteen different sequence types (STs) were identified, including ST131 (39.1%), ST38 (10.9%) and ST69 (8.7%). One E. coli isolate belonging to novel ST (ST11874) carried multiple virulence factors including genotoxin, salmochelin, aerobactin and yersiniabactin, suggesting that this isolate has potential to cause health concerns in future. Our study reveals presence of clinically relevant ARGs like blaNDM-6 and tet(X4) in pathogenic strains, which have so far not been reported from the clinics in Norway. Our study may thus, provide a framework for population-based surveillance of antibiotic resistance.

Multidrug-Resistant Extended-Spectrum β-Lactamase-Producing Escherichia coli Isolated from Vegetable Farm Soil in South Korea.

The populations of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) have increasingly disseminated in humans, animals, and the environment. This study aimed to determine the prevalence, antimicrobial susceptibilities, and molecular characteristics of ESBL-EC isolates obtained from vegetable farm soil. In total, 200 soil samples were collected from vegetable farms in Incheon, South Korea, between 2018 and 2019 and cultured on MacConkey screening plates supplemented with 2 μg/mL cefotaxime. Cefotaxime-resistant ESBL-EC isolates were recovered from 4.0% (8/200) of the soil samples. All eight isolates were nonsusceptible to ampicillin, piperacillin, cefazolin, cefotaxime, and cefepime and harbored blaCTX-M-type ESBL genes, including blaCTX-M-15 (50.0%), blaCTX-M-55 (25.0%), and blaCTX-M-14 (25.0%). Phylogenetic analysis showed that the B1 lineage was predominant (75.0%), followed by A (12.5%) and B2 (12.5%) lineages. Multilocus sequence typing revealed eight different E. coli sequence types (STs), including ST10, ST73, ST155, ST847, ST2521, ST3285, ST5173, and ST9479. Notably, ST10 and ST73 belong to the global extraintestinal pathogenic E. coli lineages. Our findings demonstrated that the farm soil environment may serve as a reservoir of human-associated multidrug-resistant ESBL-producing pathogens.

Antimicrobial Resistance Genes and Diversity of Clones among ESBL- and Acquired AmpC-Producing Escherichia coli Isolated from Fecal Samples of Healthy and Sick Cats in Portugal.

The aim of the study was to analyze the mechanisms of resistance in extended-spectrum beta-lactamase (ESBL)- and acquired AmpC (qAmpC)-producing Escherichia coli isolates from healthy and sick cats in Portugal. A total of 141 rectal swabs recovered from 98 sick and 43 healthy cats were processed for cefotaxime-resistant (CTXR) E. coli recovery (in MacConkey agar supplemented with 2 µg/mL cefotaxime). The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) method was used for E. coli identification and antimicrobial susceptibility was performed by a disk diffusion test. The presence of resistance/virulence genes was tested by PCR sequencing. The phylogenetic typing and multilocus sequence typing (MLST) were determined by specific PCR sequencing. CTXR E. coli isolates were detected in seven sick and six healthy cats (7.1% and 13.9%, respectively). Based on the synergy tests, 11 of 13 CTXR E. coli isolates (one/sample) were ESBL-producers (ESBL total rate: 7.8%) carrying the following ESBL genes: blaCTX-M-1 (n = 3), blaCTX-M-15 (n = 3), blaCTX-M-55 (n = 2), blaCTX-M-27 (n = 2) and blaCTX-M-9 (n = 1). Six different sequence types were identified among ESBL-producers (sequence type/associated ESBLs): ST847/CTX-M-9, CTX-M-27, CTX-M-1; ST10/CTX-M-15, CTX-M-27; ST6448/CTX-M-15, CTX-M-55; ST429/CTX-M-15; ST101/CTX-M-1 and ST40/CTX-M-1. Three of the CTXR isolates were CMY-2-producers (qAmpC rate: 2.1%); two of them were ESBL-positive and one ESBL-negative. These isolates were typed as ST429 and ST6448 and were obtained in healthy or sick cats. The phylogenetic groups A/B1/D/clade 1 were detected among ESBL- and qAmpC-producing isolates. Cats are carriers of qAmpC (CMY-2)- and ESBL-producing E. coli isolates (mostly of variants of CTX-M group 1) of diverse clonal lineages, which might represent a public health problem due to the proximity of cats with humans regarding a One Health perspective.

Seven-year surveillance of the prevalence of antimicrobial-resistant Escherichia coli isolates, with a focus on ST131 clones, among healthy people in Osaka, Japan

ObjectivesEscherichia coli (E. coli) is an indicator of antimicrobial resistance, and some strains of E. coli cause infectious diseases. E. coli sequence type 131 (ST131) – a global antimicrobial-resistant pandemic E. coli clone – is frequently detected in clinical specimens. Antimicrobial-resistant bacteria are monitored via national surveillance in clinical settings; however, monitoring information in non-clinical settings is limited. This study elucidated antimicrobial resistance trends of E. coli and dissemination of ST131 among healthy people in non-clinical settings. MethodsThis study collected 517 E. coli isolates from healthy people in Osaka, Japan, between 2013 and 2019. It analysed antimicrobial susceptibility of the isolates and detected the bla and mcr genes in ampicillin-resistant and colistin-resistant isolates, respectively, and the ST131 clone. ResultsAntimicrobial resistance rates of the bacteria isolated from healthy people in non-clinical settings were lower than for those in clinical settings. The resistance of the isolates to cefotaxime (4.4%) and ciprofloxacin (13.5%) gradually increased during the study period. In 23 cefotaxime-resistant isolates, the most frequent bla genes belonged to the blaCTX-M-9 group, followed by blaCTX-M-1 goup, blaTEM and blaCMY-2. One mcr-1-harbouring colistin-resistant isolate was detected in 2016. The incidence of the E. coli O25b-ST131 clone was approximately 5% until 2015 and 10% after 2016. ConclusionBoth ciprofloxacin resistance and O25b-ST131 clone frequency increased during the study period. Antimicrobial-resistant bacteria gradually spread in healthy people in non-clinical settings; one reason behind this spread was dissemination of global antimicrobial-resistant pandemic clones.

Cefotaxime resistance in invasive Haemophilus influenzae isolates in Germany 2016-19: prevalence, epidemiology and relevance of PBP3 substitutions.

Haemophilus influenzae can cause invasive infections, in which cefotaxime is among the first-line antibiotics for treatment. The prevalence of cefotaxime-resistant H. influenzae in Europe is reported to be on a low level. Nevertheless, systematic studies with a large set of invasive isolates are scarce. To provide prevalence data for cefotaxime resistance in invasive H. influenzae isolates in Germany 2016-19 and investigate the epidemiological relevance of PBP3 mutations known to elevate the cefotaxime MIC. Cefotaxime susceptibility of invasive H. influenzae isolates, collected in the national laboratory surveillance programme, was examined by gradient agar diffusion (GAD) testing. Cefotaxime resistance was determined according to EUCAST guidelines (resistance breakpoint MIC >0.125 mg/L). Therefore, the MIC for all resistant isolates was verified by broth microdilution method (BMD). WGS was performed to investigate the genetic relationship of cefotaxime-resistant isolates and to analyse alterations in the PBP3. An analysis of the geographic distribution of the resistant isolates was performed. From 2016 to 2019, the German National Reference Laboratory for Meningococci and H. influenzae received 2432 invasive H. influenzae isolates from blood and CSF. According to GAD results, 27 strains were resistant to cefotaxime. BMD confirmed the resistance in 22 of these isolates, which equals a prevalence of cefotaxime resistance of 0.90% in invasive H. influenzae in Germany. Among cefotaxime-resistant isolates cgMLST revealed three clusters. PBP3 analysis showed previously described mutations in our strains. In comparison with cefotaxime-susceptible strains, the alterations L389F and Y557H were significantly associated with cefotaxime resistance, but were not present in all resistant strains. Geographic analysis showed that the disease cases with cefotaxime-resistant H. influenzae were evenly spread throughout the population in Germany. Cefotaxime is still well suited for the treatment of invasive H. influenzae infections. Rarely occurring cefotaxime resistance is caused by sporadic mutations. The role of PBP3 mutations needs further investigation.

Epidemiology and Characterization of CTX-M-55-Type Extended-Spectrum β-Lactamase-Producing Salmonella enterica Serovar Enteritidis Isolated from Patients in Shanghai, China.

The emergence of extended-spectrum β-lactamase-producing Salmonella enterica serovar Enteritidis (ESBL-SE) in humans and foods has gained global attention. In particular, CTX-M-type ESBL-SE are increasingly being detected from various sample types. The aim of this study was to comprehensively analyze the epidemiology and characteristics of blaCTX-M-55-carrying ESBL-SE isolates of clinical origin in Shanghai, China. A total of 292 S. Enteritidis isolates were recovered from the feces and blood of outpatients and inpatients between 2006 and 2014. Overall, there was a high frequency of cefotaxime-resistant isolates (97.3%), which was significantly higher (p < 0.01) than that of isolates resistant to the other tested antibiotics. All S. Enteritidis isolates exhibited resistance to ≥1 antibiotic, and 98.0% were multidrug resistant. A total of 233 isolates were identified as ESBL-SE, 166 of which were CTX-M type. Six subtypes of CTX-M-encoding genes were detected, among which blaCTX-M-55 (91.6%, 152/166) was the most prevalent genotype. There was high genetic similarity among blaCTX-M-55-positive ESBL-SE. The blaCTX-M-55 gene in the ESBL-SE donor strains could be easily transferred into Enterobacteriaceae recipient strains. This study highlights that CTX-M-55 should be considered an important surveillance target in Shanghai, China. Cephalosporins, especially cefotaxime, must be used with caution in empirical treatment for Salmonella infections.