Urinary isolates of apramycin-resistantEscherichia coliandKlebsiella pneumoniaefrom Dublin

SUMMARYTwenty-two gentamicin-resistant urinary isolates ofEscherichia coliand five gentamicin-resistant urinary isolates ofKlebsiella pneumoniaefrom a Dublin hospital were examined for resistance to the veterinary aminoglycoside antibiotic apramycin. Five isolates ofE. coliand one isolate ofK. pneumoniaewere found to be resistant. The apramycin-resistant isolates, which were also resistant to the veterinary anthelmintic agent hygromycin B, hybridized with a DNA probe for the gene encoding the enzyme 3-N-aminoglycoside acetyltransferase type IV (AAC(3)IV). Resistance to apramycin and hygromycin B was co-transferable in four of the five isolates ofE. coliand the isolate ofK. pneumoniae.In one isolate ofE. coliapramycin resistance was not transferable. On the basis of their restriction enzyme digestion profiles and the antimicrobial resistance traits encoded, the transferable plasmids encoding resistance to apramycin and hygromycin B comprised three distinct types. Genetic linkage between the gene encoding AAC(3)IV and genes encoding resistance to ampicillin and either tetracycline or trimethoprim, means that the relatively widespread use of these antimicrobial agents provides a selective pressure for the persistence of resistance to apramycin and gentamicin even in the absence of bacterial exposure to aminoglycosides.

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RegR Virulence Regulon of Rabbit-Specific Enteropathogenic Escherichia coli Strain E22

Infection and Immunity ◽

10.1128/iai.01325-12 ◽

2013 ◽

Vol 81 (4) ◽

pp. 1078-1089 ◽

Cited By ~ 7

Author(s):

Yogitha N. Srikhanta ◽

Dianna M. Hocking ◽

Judyta Praszkier ◽

Matthew J. Wakefield ◽

Roy M. Robins-Browne ◽

...

Keyword(s):

Escherichia Coli ◽

Regulatory Protein ◽

Bioinformatic Analysis ◽

Coli Strain ◽

Mobility Shift ◽

Gene Encoding ◽

Gene Target ◽

Content Type ◽

E Coli ◽

Genes Encoding

ABSTRACTAraC-like regulators play a key role in the expression of virulence factors in enteric pathogens, such as enteropathogenicEscherichia coli(EPEC), enterotoxigenicE. coli, enteroaggregativeE. coli, andCitrobacter rodentium. Bioinformatic analysis of the genome of rabbit-specific EPEC (REPEC) strain E22 (O103:H2) revealed the presence of a gene encoding an AraC-like regulatory protein, RegR, which shares 71% identity to the global virulence regulator, RegA, ofC. rodentium. Microarray analysis demonstrated that RegR exerts 25- to 400-fold activation on transcription of several genes encoding putative virulence-associated factors, including a fimbrial operon (SEF14), a serine protease, and an autotransporter adhesin. These observations were confirmed by proteomic analysis of secreted and heat-extracted surface-associated proteins. The mechanism of RegR-mediated activation was investigated by using its most highly upregulated gene target,sefA. Transcriptional analyses and electrophoretic mobility shift assays showed that RegR activates the expression ofsefAby binding to a region upstream of thesefApromoter, thereby relieving gene silencing by the global regulatory protein H-NS. Moreover, RegR was found to contribute significantly to virulence in a rabbit infection experiment. Taken together, our findings indicate that RegR controls the expression of a series of accessory adhesins that significantly enhance the virulence of REPEC strain E22.

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Diversity of Extended-Spectrum β-Lactamases and Class C β-Lactamases among Cloacal Escherichia coli Isolates in Belgian Broiler Farms

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01285-07 ◽

2008 ◽

Vol 52 (4) ◽

pp. 1238-1243 ◽

Cited By ~ 139

Author(s):

Annemieke Smet ◽

An Martel ◽

Davy Persoons ◽

Jeroen Dewulf ◽

Marc Heyndrickx ◽

...

Keyword(s):

Escherichia Coli ◽

Broad Spectrum ◽

Antimicrobial Agents ◽

Acquired Resistance ◽

Farm Level ◽

E Coli ◽

Extended Spectrum ◽

Genes Encoding ◽

Class C ◽

Repetitive Extragenic Palindromic Pcr

ABSTRACT A total of 295 ceftiofur-resistant Escherichia coli isolates were obtained from 489 cloacal samples collected at five different Belgian broiler farms with the aim to evaluate the diversity of this resistance at the farm level. Strains were examined for resistance against β-lactam antibiotics and other antimicrobial agents by using disk diffusion tests. Three different β-lactam resistance phenotypes suggested the presence of an extended-spectrum β-lactamase (ESBL), a class C β-lactamase, or the combination of an ESBL with a class C β-lactamase. Seventy-six percent of these isolates also showed acquired resistance to other antimicrobial agents. After genotyping by repetitive extragenic palindromic-PCR, 51 unrelated E. coli strains were selected for further analyses. Isoelectric focusing and sequencing of the amplicons obtained in PCRs for the detection of genes encoding broad-spectrum β-lactamase enzymes revealed the following ESBLs: TEM-52 (13.2%), TEM-106 (2%), CTX-M-1 (27.4%), CTX-M-2 (7.8%), CTX-M-14 (5.9%), and CTX-M-15 (2%). The only plasmidic AmpC β-lactamase found in this study was the CMY-2 enzyme (49%). Mutations in the promoter and attenuator regions of the chromosomal ampC gene were found only in association with bla CMY-2 genes and ESBL genes. The combination of an ESBL (CTX-M-1) with a plasmidic AmpC β-lactamase (CMY-2) was found in 7.8% of the isolates. These data show that ceftiofur-resistant E. coli strains are often present in cloacal samples of broilers at the farm level in Belgium. The diversity of broad-spectrum β-lactamases among these isolates is high, and they may act as a reservoir of ESBL and ampC genes.

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Co-Occurrence of Plasmid-Mediated AmpC β-Lactamase Activity Among Klebsiella pneumoniae and Escherichia Coli

The Open Microbiology Journal ◽

10.2174/1874285801711010195 ◽

2017 ◽

Vol 11 (1) ◽

pp. 195-202 ◽

Cited By ~ 6

Author(s):

Abdulaziz Zorgani ◽

Hiyam Daw ◽

Najib Sufya ◽

Abdullah Bashein ◽

Omar Elahmer ◽

...

Keyword(s):

Escherichia Coli ◽

Klebsiella Pneumoniae ◽

Multidrug Resistant ◽

Control Measures ◽

Gene Encoding ◽

E Coli ◽

Infection Control Measures ◽

Genes Encoding ◽

Polymerase Chain ◽

Variant Enzyme

Introduction: Extended-spectrum β-lactamases (ESBLs), including the AmpC type, are important mechanisms of resistance among Klebsiella pneumoniae and Escherichia coli isolates. Objective: The aim of the study was to investigate the occurrence of AmpC-type β-lactamase producers isolated from two hospitals in Tripoli, Libya. Methods: All clinical isolates (76 K. pneumoniae and 75 E. coli) collected over two years (2013-2014) were evaluated for susceptibility to a panel of antimicrobials and were analyzed phenotypically for the ESBL and AmpC phenotype using E-test and ESBL and AmpC screen disc test. Both ESBL and AmpC-positive isolates were then screened for the presence of genes encoding plasmid-mediated AmpC β-lactamases by polymerase chain reaction (PCR). Results: Of the K. pneumoniae and E. coli tested, 75% and 16% were resistant to gentamicin, 74% and 1.3% to imipenem, 71% and 12% to cefoxitin, 80% and 12% to cefepime, 69% and 22.6% to ciprofloxacin, respectively. None of the E. coli isolates were multidrug resistant compared with K. pneumoniae (65.8%). K. pneumoniae ESBL producers were significantly higher (85.5%) compared with (17.3%) E. coli isolates (P <0.0001, OR=4.93). Plasmid-mediated AmpC genes were detected in 7.9% of K. pneumoniae, and 4% E. coli isolates. There was low agreement between phenotypic and genotypic methods, phenotypic testing underestimated detection of AmpC enzyme and did not correlate well with molecular results. The gene encoding CMY enzyme was the most prevalent (66.6%) of AmpC positive isolates followed by MOX, DHA and EBC. Only one AmpC gene was detected in 5/9 isolates, i.e, blaCMY (n=3), bla MOX (n=1), blaDHA (n=1). However, co-occurrence of AmpC genes were evident in 3/9 isolates with the following distribution: bla CMY and blaEBC (n=1), and blaCMY and blaMOX (n=2). Neither blaFOX nor blaACC was detected in all tested isolates. All AmpC positive strains were resistant to cefoxitin and isolated from patients admitted to intensive care units. Conclusion: Further studies are needed for detection of other AmpC variant enzyme production among such isolates. Continued surveillance and judicious antibiotic usage together with the implementation of efficient infection control measures are absolutely required.

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Chlamydia trachomatis Serovar L2 Can Utilize Exogenous Lipoic Acid through the Action of the Lipoic Acid Ligase LplA1

Journal of Bacteriology ◽

10.1128/jb.00717-10 ◽

2010 ◽

Vol 192 (23) ◽

pp. 6172-6181 ◽

Cited By ~ 8

Author(s):

Aishwarya V. Ramaswamy ◽

Anthony T. Maurelli

Keyword(s):

Chlamydia Trachomatis ◽

Lipoic Acid ◽

Open Reading Frames ◽

Sequence Motifs ◽

Gene Encoding ◽

E Coli ◽

Genes Encoding ◽

Surrogate Host ◽

Lipoate Synthase

ABSTRACT Lipoic acid is an essential protein bound cofactor that is vital for the functioning of several important enzymes involved in central metabolism. Genomes of all sequenced chlamydiae show the presence of two genes encoding lipoic acid ligases and one gene encoding a lipoate synthase. However, the roles of these proteins in lipoic acid utilization or biosynthesis have not yet been characterized. The two distinct lipoic acid ligases in Chlamydia trachomatis serovar L2, LplA1Ct and LplA2Ct (encoded by the open reading frames ctl0537 and ctl0761) display moderate identity with Escherichia coli LplA (30 and 27%, respectively) but possess amino acid sequence motifs that are well conserved among all lipoyl protein ligases. The putative lipoic acid synthase LipACt, encoded by ctl0815, is ca. 43% identical to the E. coli LipA homolog. We demonstrate here the presence of lipoylated proteins in C. trachomatis serovar L2 and show that the lipoic acid ligase LplA1Ct is capable of utilizing exogenous lipoic acid for the lipoylation Therefore, host-derived lipoic acid may be important for intracellular growth and development. Based on genetic complementation in a surrogate host, our study also suggests that the C. trachomatis serovar L2 LipA homolog may not be functional in vivo.

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Construction of a complete set of Neisseria meningitidis mutants and its use for the phenotypic profiling of this human pathogen

Nature Communications ◽

10.1038/s41467-020-19347-y ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Alastair Muir ◽

Ishwori Gurung ◽

Ana Cehovin ◽

Adelme Bazin ◽

David Vallenet ◽

...

Keyword(s):

Neisseria Meningitidis ◽

Bacterial Pathogen ◽

Essential Genes ◽

Gene Encoding ◽

Complete Collection ◽

Protein Coding ◽

Type Iv ◽

Membrane Structure And Function ◽

Genes Encoding ◽

Information Cell

Abstract The bacterium Neisseria meningitidis causes life-threatening meningitis and sepsis. Here, we construct a complete collection of defined mutants in protein-coding genes of this organism, identifying all genes that are essential under laboratory conditions. The collection, named NeMeSys 2.0, consists of individual mutants in 1584 non-essential genes. We identify 391 essential genes, which are associated with basic functions such as expression and preservation of genome information, cell membrane structure and function, and metabolism. We use this collection to shed light on the functions of diverse genes, including a gene encoding a member of a previously unrecognised class of histidinol-phosphatases; a set of 20 genes required for type IV pili function; and several conditionally essential genes encoding antitoxins and/or immunity proteins. We expect that NeMeSys 2.0 will facilitate the phenotypic profiling of a major human bacterial pathogen.

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Identification of an Operon Required for Ferrichrome Iron Utilization in Vibrio cholerae

Journal of Bacteriology ◽

10.1128/jb.182.8.2350-2353.2000 ◽

2000 ◽

Vol 182 (8) ◽

pp. 2350-2353 ◽

Cited By ~ 49

Author(s):

Marc B. Rogers ◽

Jessica A. Sexton ◽

G. Joel DeCastro ◽

Stephen B. Calderwood

Keyword(s):

Escherichia Coli ◽

Vibrio Cholerae ◽

Predicted Amino Acid Sequence ◽

Gene Fusions ◽

Gene Encoding ◽

E Coli ◽

Atp Binding Cassette Transporter ◽

Genes Encoding ◽

Iron Utilization

ABSTRACT Mutagenesis of Vibrio cholerae with TnphoA, followed by screening for fusions that were activated under low-iron conditions, led to the identification of seven independent fusion strains, each of which was deficient in the ability to utilize ferrichrome as a sole iron source for growth in a plate bioassay and had an insertion in genes encoding products homologous toEscherichia coli FhuA or FhuD. Expression of the gene fusions was independent of IrgB but regulated by Fur. We report here a map of the operon and the predicted amino acid sequence of FhuA, based on the nucleotide sequence. Unlike those of the E. coli fhuoperon, the V. cholerae ferrichrome utilization genes are located adjacent and opposite in orientation to a gene encoding an ATP-binding cassette transporter homolog, but this gene, if disrupted, does not affect the utilization of ferrichrome in vitro.

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Understanding the Role of Prevotella Genus in the Digestion of Lignocellulose and Other Substrates in Vietnamese Native Goats’ Rumen by Metagenomic Deep Sequencing

Animals ◽

10.3390/ani11113257 ◽

2021 ◽

Vol 11 (11) ◽

pp. 3257

Author(s):

Trong-Khoa Dao ◽

Thi-Huyen Do ◽

Ngoc-Giang Le ◽

Hong-Duong Nguyen ◽

Thi-Quy Nguyen ◽

...

Keyword(s):

Deep Sequencing ◽

Gene Encoding ◽

Amylolytic Enzymes ◽

E Coli ◽

Lignocellulose Conversion ◽

Genes Encoding ◽

Abundant Genus ◽

First Time ◽

Goat Rumen

Bacteria in rumen play pivotal roles in the digestion of nutrients to support energy for the host. In this study, metagenomic deep sequencing of bacterial metagenome extracted from the goats’ rumen generated 48.66 GB of data with 3,411,867 contigs and 5,367,270 genes. The genes were mainly functionally annotated by Kyoto Encyclopedia of Genes and Genomes (KEGG) Carbohydrate-Active enZYmes (CAZy), and HMMER database, and taxonomically classified by MEGAN. As a result, 65,554 genes encoding for 30 enzymes/proteins related to lignocellulose conversion were exploited, in which nine enzymes were seen for the first time in goat rumen. Prevotella was the most abundant genus, contributing 30% hemicellulases and 36% enzymes/proteins for lignocellulose pretreatment, and supporting 98.8% of feruloyl esterases and 71.7% acetylxylan esterases. In addition, 18 of the 22 most lignocellulose digesting- potential contigs belonged to Prevotella. Besides, Prevotella possessed many genes coding for amylolytic enzymes. One gene encoding for endoxylanase was successfully expressed in E. coli. The recombinant enzyme had high Vmax, was tolerant to some salts and detergents, worked better at pH 5.5–6.5, temperature 40–50 °C, and was capable to be used in practices. Based on these findings, we confirm that Prevotella plays a pivotal role for hemicellulose digestion and significantly participates in starch, cellulose, hemicellulose, and pectin digestion in the goat rumen.

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Prevalence of Escherichia colicarrying a gene encoding ESBLs in patients with common infectious diseases visiting primary health care centres in some provinces and cities of Vietnam

Ministry of Science and Technology, Vietnam ◽

10.31276/vjst.63(12).19-24 ◽

2021 ◽

Vol 63 (12) ◽

pp. 19-24

Author(s):

Thi Mai Hung Tran ◽

◽

Thi Hong Duong ◽

Minh Tan Luong ◽

Thi Trang Le ◽

...

Keyword(s):

Health Care ◽

Primary Health Care ◽

Urinary Tract ◽

Urinary Tract Infections ◽

Skin Infections ◽

Gene Encoding ◽

E Coli ◽

Primary Health ◽

Genes Encoding ◽

Tract Infections

The objective of the study was to determine the prevalence of E. coli carrying the gene encoding ESBLs in patients with common diseases visiting primary health care centres in 8 provinces of the Northern region (Ha Noi, Ha Nam, Hai Duong, Bac Ninh), the Central region (Thua Thien - Hue, Khanh Hoa), and the Southern region (Can Tho, Ben Tre) of Vietnam. A cross-sectional study was implemented on patients with symptoms of diarrhea, urinary tract infections, skin infections, and respiratory infections. The study used questionnaires to collect epidemiological information and samples to culture, isolate and test E. coli carrying genes encoding ESBLs by PCR technique. The results showed that the percentage of E. coli bacteria carrying genes encoding ESBLs was relatively high (57.4%), the highest rate was in E. coli bacteria on patients with diarrhea (65.4%), followed by urinary tract infections (22.1%), pneumonia (8.82%) and skin infections (3.68%). The rate of co-infection with two genes accounted for 40.9%. The TEM gene was dominant (88.2%), followed by the CTX-M gene (51%). Different types of specimens were also found to have a different rate of carrying this gene. E. coli isolated in the Southern region has a lower risk of carrying genes encoding antibiotic-resistant ESBL, only 42% of the Nothern region’s rates (RR=0.42, p<0.001). Families that used antibiotics also had a higher rate of being infected with bacteria carrying genes encoding ESBLs than families that did not use antibiotics.

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Profiles of virulence genes in enterotoxigenic Escherichia coli isolates from suckling piglets in Serbia

Medycyna Weterynaryjna ◽

10.21521/mw.6326 ◽

2020 ◽

Vol 76 (01) ◽

pp. 6326-2020

Author(s):

JADRANKA ŽUTIĆ ◽

OLIVERA VALČIĆ ◽

VESNA MILIĆEVIĆ ◽

LJUBIŠA VELJOVIĆ ◽

JASNA KURELJUŠIĆ ◽

...

Keyword(s):

Escherichia Coli ◽

Virulence Factors ◽

Virulence Genes ◽

Enterotoxigenic Escherichia Coli ◽

Gene Encoding ◽

E Coli ◽

Genes Encoding ◽

Virulence Pattern ◽

Suckling Piglets ◽

Asta Gene

A total of 120 Escherichia coli (E. coli) strains from suckling piglets with diarrhoea and 30 E. coli strains from healthy piglets were tested for the presence of fimbrial and enterotoxin virulence genes. Out of the 120 isolates sampled from diarrheic piglets, 81 (67.5%) expressed one or more genes encoding virulence factors. Adhesin genes were detected in 52 (43.33%) out of 120 E. coli isolates, and the most common among them was F4 adhesin (33.33%). Genes encoding E. coli toxins were detected in 81 (67.5%) isolates. E. coli included in the study carried genes for one or more of the following toxins: STa, STb, LT and EAST1. The astA gene encoding EAST1 was the most prevalent and was identified in 72 (60%) E. coli isolates. EAST1 toxin was detected in 5 out of 30 isolates (16.7%) from healthy piglets. Among the 81 isolates expressing virulence genes, a total of 15 different combinations for fimbrial and toxin genes were found. The most common virulence pattern was F4/STb/LT/EAST1 detected in 23.45% of E. coli strains isolated from suckling piglets with diarrhoea. The results indicate that F4 adhesin and EAST1 toxin are the most common in E. coli isolates sampled from diarrhoeic suckling piglets in Serbia.

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Molecular Characterization and Epidemiology of Extended-Spectrum- β-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Isolates Causing Health Care-Associated Infection in Thailand, Where the CTX-M Family Is Endemic

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00171-08 ◽

2008 ◽

Vol 52 (8) ◽

pp. 2818-2824 ◽

Cited By ~ 123

Author(s):

Pattarachai Kiratisin ◽

Anucha Apisarnthanarak ◽

Chaitat Laesripa ◽

Piyawan Saifon

Keyword(s):

Escherichia Coli ◽

Health Care ◽

Klebsiella Pneumoniae ◽

Antimicrobial Agents ◽

Upstream Region ◽

University Hospitals ◽

E Coli ◽

Extended Spectrum ◽

Genes Encoding ◽

Health Care Associated Infection

ABSTRACT Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae have rapidly spread worldwide and pose a serious threat for health care-associated (HA) infection. We conducted molecular detection and characterization of ESBL-related bla genes, including bla TEM, bla SHV, bla CTX-M, bla VEB, bla OXA, bla PER, and bla GES, among 362 isolates of ESBL-producing E. coli (n = 235) and ESBL-producing K. pneumoniae (n = 127) collected from patients who met the definition of HA infection at two major university hospitals in Thailand from December 2004 to May 2005. The prevalence of ESBL-producing E. coli and ESBL-producing K. pneumoniae, patient demographics and the susceptibilities of these bacteria to various antimicrobial agents were described. A total of 87.3% of isolates carried several bla genes. The prevalence of bla CTX-M was strikingly high: 99.6% for ESBL-producing E. coli (CTX-M-14, -15, -27, -40, and -55) and 99.2% for ESBL-producing K. pneumoniae (CTX-M-3, -14, -15, -27, and -55). ISEcp1 was found in the upstream region of bla CTX-M in most isolates. Up to 77.0% and 71.7% of ESBL-producing E. coli and ESBL-producing K. pneumoniae, respectively, carried bla TEM; all of them encoded TEM-1. ESBL-producing K. pneumoniae carried bla SHV at 87.4% (SHV-1, -2a, -11, -12, -27, -71, and -75) but only at 3.8% for ESBL-producing E. coli (SHV-11 and -12). bla genes encoding VEB-1 and OXA-10 were found in both ESBL-producing E. coli (8.5% and 8.1%, respectively) and ESBL-producing K. pneumoniae (10.2% and 11.8%, respectively). None of the isolates were positive for bla PER and bla GES. Pulsed-field gel electrophoresis analysis demonstrated that there was no major clonal relationship among these ESBL producers. This is the first study to report CTX-M-3, CTX-M-27, CTX-M-40, SHV-27, SHV-71, and SHV-75 in Thailand and to show that CTX-M ESBL is highly endemic in the country.

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