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Twenty bacteria were isolated from four ant lion larvae. The isolates were classified into three groups by biological characteristics. Since Group I, Group II and Group III were isolated from individual larvae Kuo1, Kuo3, 4 and Ku...
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Twenty bacteria were isolated from four ant lion larvae. The isolates were classified into three groups by biological characteristics. Since Group I, Group II and Group III were isolated from individual larvae Kuo1, Kuo3, 4 and Kuo2, respectively, with exception of one isolate Kuo2-1, each ant lion tested had its own dominant bacterial flora. Groups I and II were closer to Serratia liquefaciens and Enterobacter cloacae, respectively, whereas Group III could not be identified by the test used. The phylogenetic analysis of GroEL amino acid sequences revealed that Group I, II and III were related to those of Serratia spp., E. cloacae and Salmonella spp. -Escherichia/Shigella spp., respectively. Among these groups, Group I was highly virulent against Bombyx mori and Periplaneta americana, and caused 100% mortality within 24 h. The other two groups (Group II and III) were avirulent to these insect species. The culture filtrate of Group I caused killing activity to B. mori larvae and the insecticidal substance was purified from culture filtrate of Group I bacterium. Since the insecticidal activity highly correlated with proteolytic activity in the chromatographies, Group I bacterium may secret insecticidal proteinase in vitro.
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Исследованы сульфамидустойчивые (Sul~R) природные штаммы энтеробактерий (11.9% отобщего числа 797 культур, выделенных в составе мик...
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Исследованы сульфамидустойчивые (Sul~R) природные штаммы энтеробактерий (11.9% отобщего числа 797 культур, выделенных в составе микрофлоры кишечника медоносной пчелы, пчелиной обножки-пыльцы и растительного материала) на присутствие интегронов антибиотикорезистентности 1-го класса (MRI). Только 5.3% от числа Sul~R-изолятов оказались MRI-позитивными. Показана мутационная изменчивость последовательности слабого ("дикий тип") промотора MRI. У изолятов Klebsiella oxytoca амплифицирован более активный гибридный тип промотора. Регуляторные генетические модификации в MRI могут представлять опасность, приводя к развитию множественной лекарственной устойчивости условнопатогенных штаммов.
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Objectives: The aim of this study was to compare clearance rates and related characteristics of patients carrying KPC-producing carbapenemase-producing Enterobacteriaceae (CPE) with those of patients carrying NDM-1-producing CPE.
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The Enterobacteriaceae are among the most important causes of serious nosocomial and community-onset bacterial infections in humans, and resistance to antimicrobial agents in these species has become an increasingly relevant probl...
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The Enterobacteriaceae are among the most important causes of serious nosocomial and community-onset bacterial infections in humans, and resistance to antimicrobial agents in these species has become an increasingly relevant problem for healthcare providers. β-lactam and fluoroquinolone antibiotics are important drug classes used to treat infections caused by Enterobacteriaceae. Emerging resistance mechanisms against these agents have recently been described in Enterobacteriaceae and include the production of newer β-lactamases and plasmid-mediated quinolone resistance. The newer β-lactamases consist of the following: plasmid-mediated AmpC β-lactamases (e.g., ephamycin [CMY], CMY types), extended-spectrum β-lactamases (e.g., cefotaxime [CTX], CTX-M first isolated at Munich) and carbapenem-hydrolyzing enzymes (e.g., Klebsiella pneumoniae carbapenemase [KPC], KPC types and the metallo-β-lactamases). Recent developments in the epidemiology, clinical relevance and laboratory detection of infections caused by multiresistant Enterobacteriaceae with these new types of resistance mechanisms will be addressed in this review.
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Цель исследования — определить основные механизмы инфицирования энтеробактериями с продукцией бета-лактамаз расширенного с...
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Цель исследования — определить основные механизмы инфицирования энтеробактериями с продукцией бета-лактамаз расширенного спектра (БЛРС) у гематологических больных. Материал и методы. В проспективное исследование (2013—2015 гг.) были включены случаи бактериемии, вызванные энтеробактериями. Мазки со слизистой оболочки прямой кишки брали в течение первых трёх суток после получения гемокультуры. Для детекции БЛРС были использованы фенотипические методы. Гены резистентности групп определяли методом ПЦР. Генотипирование проводили методом ERIC-ПЦР. Результаты. В 89 случаях бактериемии был выделен 91 изолят энтеробактерий (56% — E.coli, 26% — K.pneumoniae, 18% — другие) у 82 больных (медиана возраста 50 лет). Продукция БЛРС была у 19 (21%) изоля-тов (E.coli — л=11, K.pneumoniae — и=8). Бета-лактамазы СТХ-М типа были определены у 95% изолятов. Колонизация слизистой оболочки прямой кишки, идентичными по виду энтеробактериями с продукцией БЛРС, была во всех 19 случаях бактериемии, вызванной БЛРС положительными энтеробактериями, и только в 8 (11%) из 72 при выделении из гемокультуры энтеробактерий без продукции БЛРС (р<0,0001). Генотипирование 19 продуцентов БЛРС из гемокультуры выявило генетическую идентичность только у двух изолятов E.coli, выделенных от одного пациента с интервалом в два месяца. При попарном генотипировании продуцентов БЛРС, выделенных из гемокультуры и со слизистой прямой кишки, генетически родственными были 26% пар изолятов. Заключение. У больных с опухолями системы крови и бактериемией, вызванной энтеробактериями с продукцией БЛРС, преобладает эндогенный путь инфицирования.
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Aims: Enumeration of coliform bacteria and Escherichia coli is the most widely used method in the estimation of hygienic quality of drinking water. The yield of target bacteria and the species composition of different populations ...
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Aims: Enumeration of coliform bacteria and Escherichia coli is the most widely used method in the estimation of hygienic quality of drinking water. The yield of target bacteria and the species composition of different populations of coliform bacteria may depend on the method. Three methods were compared.
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Objectives The novel carbapenem/beta-lactamase inhibitor combination imipenem/cilastatin/relebactam has been developed for the treatment of infections due to carbapenemase-producing Enterobacteriaceae (CPE). Herein, we describe th...
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Objectives The novel carbapenem/beta-lactamase inhibitor combination imipenem/cilastatin/relebactam has been developed for the treatment of infections due to carbapenemase-producing Enterobacteriaceae (CPE). Herein, we describe the in vivo evolution of imipenem/cilastatin/relebactam resistance in longitudinal intra-patient Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (KPC-Kp) strains isolated from a patient following ceftazidime/avibactam-based treatments. Methods WGS analysis was performed on KPC-Kp strains isolated at different times and during antimicrobial treatments from the same patient. Genome assemblies were performed using a hybrid approach using Illumina iSeq 100 and Minion Oxford Nanopore platforms. Subpopulation analysis and allele frequency determination was performed by mapping Illumina reads to bla(KPC). Results During antimicrobial treatment, resistance to ceftazidime/avibactam was observed following 16 days of antimicrobial therapy. WGS results showed that all KPC-Kp exhibited a low SNP rate of divergence, belonged to ST512 and shared similar antimicrobial resistance and porin gene patterns. Genetic analysis demonstrated that the first ceftazidime/avibactam-resistant KPC-Kp strain harboured a bla(KPC-53) gene in a Tn4401 transposon moved from IncFII(K) to a 43 kb IncX3 plasmid, while a imipenem/cilastatin/relebactam-resistant strain exhibited two copies of the Tn4401 transposon in IncFII(K) and IncX3 plasmids, resulting in an increased bla(KPC) copy number. Of note, frequency analysis demonstrated that imipenem/cilastatin/relebactam-resistant KPC-Kp consisted of mixed subpopulations harbouring bla(KPC-40) and bla(KPC-53) alleles. Conclusions Our results show the in vivo evolution of genetic rearrangement conferring resistance to imipenem/relebactam in a patient with KPC-Kp infection and treated with different ceftazidime/avibactam-based treatments. The rapid development of mutations and the high adaptability of its genome highlight the potential threat of KPC-Kp.
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Background: Our study was to investigate the prevalence of carbapenemase genes in strains of Enterobacteriaceae species exhibiting decreased susceptibility to carbapenems in our hospital. Methods: The carbapenemase producing Enter...
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Background: Our study was to investigate the prevalence of carbapenemase genes in strains of Enterobacteriaceae species exhibiting decreased susceptibility to carbapenems in our hospital. Methods: The carbapenemase producing Enterobacteriaceae species were confirmed by modified Hodge test (MHT) and EDTA-disc synergy test which indicating the production of class B carbapenemases. PCR and sequencing analysis were used to identify the drugresistant genes. DNA fingerprinting based on enterobacterial repetitive intergenic consensus (ERIC)-PCR was applied to investigate the homology of Enterobacteriaceae species. Results: From a collection of 1,472 Enterobacteriaceae species, 18 isolates with decreased susceptibility to carbapenem treatment were identified and 9 of which were positive by MHT, and 6 of which produced class B carbapenemases. PCR and sequencing analysis of the 18 isolates revealed 4 different carbapenemase genes (blaIMP-8, blaoxa-1, blaIMP-26, and blaoxa-47) in 10 isolates, with the blaIMP-8 and blaoxa-1 genes being the most common (60-70% prevalence). ERIC-PCR showed 5, 2, and 2 unique genotypes for Enterobacter cloacae, Escherichia coli, and Klebsiella pneumoniae, respectively. Three E. coli strains isolated from different patients from the urologic surgery department exhibited the same DNA banding pattern, suggesting a possible clonal dissemination. Majority (17/18) of the carbapenem- unsusceptible Enterobacteriaceae species isolates was obtained from the surgery department of our hospital. Conclusions: The main carbapenemase genes of Enterobacteriaceae species in our hospital were blaIMP-8 and blaoxa-1. Prevalence of carbapenem resistance may be existed in surgery department and infection control should be taken for preventing further dissemination of drug-resistant strains.
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Objectives To determine the transmission and molecular characteristics of bla(NDM)-producing Escherichia coli between companion animals and their healthcare providers at veterinary clinics in Guangzhou, China. Methods A total of 3...
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Objectives To determine the transmission and molecular characteristics of bla(NDM)-producing Escherichia coli between companion animals and their healthcare providers at veterinary clinics in Guangzhou, China. Methods A total of 359 samples from companion animals and their healthcare providers were collected at 14 veterinary clinics in Guangzhou, China. Genomic characteristics and clonal relationships for bla(NDM)-positive E. coli and complete plasmid sequences were characterized based on WGS data from combined Illumina and MinION platform reads. Results Forty-five bla(NDM)-positive bacteria were recovered from companion animals (n = 43) and their healthcare providers (n = 2) at 10 veterinary clinics. Overall, E. coli (73.3%, 33/45) and Klebsiella pneumoniae (13.3%, 6/45) were the most prevalent species among the seven species of bla(NDM)-positive bacteria. Four bla(NDM) variants (bla(NDM-1), bla(NDM-4), bla(NDM-5) and bla(NDM-7)) were identified in 45 bla(NDM)-positive bacteria and bla(NDM-5) was the most prevalent (77.8%, 35/45). WGS indicated that the most prevalent STs were ST405 (8/33), ST453 (6/33), ST457 (6/33) and ST410 (5/33) among the 33 bla(NDM)-positive E. coli isolates. Phylogenomics and PFGE analysis revealed that clonal spread of bla(NDM)-positive ST453 E. coli isolates between companion animals and their healthcare providers was evident. In addition, two novel IncFIB plasmids carrying bla(NDM-4) (pF765_FIB and pG908_FIB) were found in this study and indicated that IS26 may promote the horizontal transmission of bla(NDM) between different plasmid types. Conclusions In this study we conducted a large-scale investigation on the prevalence of bla(NDM)-positive E. coli isolates from companion animals and their healthcare providers and revealed the clonal spread of bla(NDM)-positive E. coli isolates between these two groups.
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AIMS: This study was performed to identify bacterial strains isolated simultaneously with Pantoea species from Eucalyptus trees showing symptoms of bacterial blight and dieback in Uruguay. METHODS AND RESULTS: Several molecular te...
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AIMS: This study was performed to identify bacterial strains isolated simultaneously with Pantoea species from Eucalyptus trees showing symptoms of bacterial blight and dieback in Uruguay. METHODS AND RESULTS: Several molecular techniques including 16S rRNA and rpoB gene sequencing and DNA-DNA hybridization were used to characterize the gram-negative, facultatively anaerobic, slime-producing bacterial strains isolated along with Pantoea species from Eucalyptus. Hypersensitivity reactions (HR) and pathogenicity tests were performed on tobacco and Eucalyptus seedlings, respectively. The isolates clustered closely with the type strain of Enterobacter cowanii in both phylogenetic trees constructed. The DNA-DNA similarity between the isolates and the type strain of Ent. cowanii ranged from 88% to 92%. A positive HR was observed on the tobacco seedlings, but no disease symptoms were visible on the inoculated Eucalyptus seedlings. CONCLUSIONS: Enterobacter cowanii was isolated from trees with symptoms of bacterial blight although strains of this bacterial species do not appear to be the causal agent of the disease. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides the first report of Ent. cowanii isolated from Eucalyptus. Its presence in Eucalyptus tissue suggests that it is an endophyte in trees showing symptoms of blight.
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