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1.
J Microbiol ; 59(9): 854-860, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34382147

RESUMO

Extraintestinal pathogenic Escherichia coli (ExPEC) is an important zoonotic pathogen that places severe burdens on public health and animal husbandry. There are many pathogenic factors in E. coli. The type VI secretion system (T6SS) is a nano-microbial weapon that can assemble quickly and inject toxic effectors into recipient cells when danger is encountered. T6SSs are encoded in the genomes of approximately 25% of sequenced Gram-negative bacteria. When these bacteria come into contact with eukaryotic cells or prokaryotic microbes, the T6SS assembles and secretes associated effectors. In the porcine ExPEC strain PCN033, we identified four classic rearrangement hotspot (Rhs) genes. We determined the functions of the four Rhs proteins through mutant construction and protein expression. Animal infection experiments showed that the Δrhs-1CT, Δrhs-2CT, Δrhs-3CT, and Δrhs-4CT caused a significant decrease in the multiplication ability of PCN033 in vivo. Cell infection experiments showed that the Rhs protein is involved in anti-phagocytosis activities and bacterial adhesion and invasion abilities. The results of this study demonstrated that rhs1, rhs3, and rh4 plays an important role in the interaction between PCN033 and host cell. Rhs2 has contribution to cell and mice infection. This study helps to elucidate the pathogenic mechanism governing PCN033 and may help to establish a foundation for further research seeking to identify potential T6SS effectors.


Assuntos
Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/metabolismo , Doenças dos Suínos/microbiologia , Animais , Aderência Bacteriana , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Escherichia coli Extraintestinal Patogênica/genética , Escherichia coli Extraintestinal Patogênica/metabolismo , Feminino , Intestinos/microbiologia , Camundongos , Família Multigênica , Suínos
2.
Malawi Med J ; 33(1): 59-64, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-34422235

RESUMO

Background: Non-susceptibility of bacteria to antiseptic agents used for preoperative skin preparations threaten the effectiveness of prevention of surgical site infections. Data concerning susceptibility of multidrug resistant bacteria strains to antiseptic agents was limited at our setting. This study presents the susceptibility of extended spectrum ß-lactamases producing Klebsiella pneumoniae and Escherichia coli (with and without biofilm formation) to antiseptic agents used for preoperative skin preparations at zonal referral hospital in Mwanza, Tanzania. Methods: This cross-sectional descriptive study was conducted through July 2020. Presumptive extended spectrum beta-lactamase producing Klebsiella pneumoniae and Escherichia coli were recovered for this study. Disc combination method was used to confirm production of ESBL while tube method was used to detect biofilms formation. Then, isolates were tested for susceptibility towards 10% povidone iodine, 70% methylated spirit, 50% hydrogen peroxide (6% of industrial H2O2 diluted in equal volume with sterile distilled water) and 2% chlorhexidine. STATA software version 13.0 was used for data analysis. Results: A total of 31 presumptive ESBL producers were recovered and phenotypically confirmed, whereas 54.8% (n=17) were K. pneumoniae and 45.2% (n=14) were E. coli. Five (35.7%) E. coli and seven (41.2%) K. pneumoniae had positive biofilms test results. Four (12.9%) bacteria were non-susceptible to antiseptic agents used for preoperative skin preparations. However, none exhibited resistance towards 10% PVP-I. Conclusion: In this study we highlight the existence of multidrug resistant Gram-negative bacteria with resistance to antiseptic agents used for preoperative skin preparation at a zonal referral hospital in Mwanza, Tanzania.


Assuntos
Anti-Infecciosos Locais/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Anti-Infecciosos Locais/uso terapêutico , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Biofilmes , Estudos Transversais , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/isolamento & purificação , Humanos , Infecções por Klebsiella/tratamento farmacológico , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Tanzânia
3.
Viruses ; 13(7)2021 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-34372554

RESUMO

Urinary tract infections (UTIs) are among the events that most frequently need medical intervention. Uropathogenic Escherichia coli are frequently their causative agents and the infections are sometimes complicated by the presence of polyresistant nosocomial strains. Phage therapy is a tool that has good prospects for the treatment of these infections. In the present study, we isolated and characterized two bacteriophages with broad host specificity against a panel of local uropathogenic E. coli strains and combined them into a phage cocktail. According to genome sequencing, these phages were closely related and belonged to the Tequatrovirus genus. The newly isolated phages showed very good activity on a panel of local clinical E. coli strains from urinary tract infections. In the form of a two-phage cocktail, they were active on E. coli strains belonging to phylogroups B2 and D, with relatively lower activity in B1 and no response in phylogroup A. Our study is a preliminary step toward the establishment of a national phage bank containing local, well-characterized phages with therapeutic potential for patients in Slovakia.


Assuntos
Myoviridae/genética , Terapia por Fagos/métodos , Escherichia coli Uropatogênica/genética , Antibacterianos/farmacologia , Bacteriófagos/genética , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/terapia , Especificidade de Hospedeiro/genética , Humanos , Eslováquia , Infecções Urinárias/microbiologia , Infecções Urinárias/terapia , Escherichia coli Uropatogênica/efeitos dos fármacos , Escherichia coli Uropatogênica/isolamento & purificação , Fatores de Virulência/genética
4.
J Med Microbiol ; 70(8)2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34402781

RESUMO

A previous study conducted in Gabon, Central Africa, in 2010/11 found a high colonization rate with extended-spectrum ß-lactamase-producing enterobacterales (ESBL-E) among children of ~34 %. Eight years later, we aimed to reassess the ESBL-E rate and previously identified risk factors for colonization in children from Gabon. We conducted a cross-sectional cohort study in 2018 on 92 outpatients under 5 years of age with diarrhoea in Lambaréné, Gabon, in whom a rectal swab was obtained at the initial medical encounter (baseline). Fifty-eight of these provided a further rectal swab 1 week afterwards. ESBL-E colonization was assessed [following the European Committee on Antimicrobial Susceptibility Testing (EUCAST)], and in confirmed ESBL-E isolates the susceptibility to meropenem and the prevalence of the most abundant ESBL genes, bla CTX-M, bla SHV, and bla TEM, were investigated. At baseline, the ESBL-E colonization rate was 57 % (52/92; 95 % CI: 46-67). Hospitalization during the previous year, chicken consumption in the past week and young age were identified as independent risk factors for ESBL-E colonization at baseline. On day 7, the ESBL-E carriage rate was 72 % (42/58; 95 % CI: 59-83). All ESBL-E isolates (n=293) were susceptible to meropenem and bla CTX-M was the most frequently detected ß-lactamase gene. The ESBL-E colonization rate among children from Gabon is alarmingly high, with indications of further increase over recent years. While all ESBL-E strains remain currently susceptible to meropenem, in practice no adequate treatment is available locally for severe infections with such isolates. It is thus of the utmost importance to invest in improved hospital infection prevention and control measures to combat ESBL-E effectively.


Assuntos
Enterobacteriáceas Resistentes a Carbapenêmicos/fisiologia , Portador Sadio/microbiologia , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Criança , Estudos Transversais , Gabão/epidemiologia , Humanos , Vigilância em Saúde Pública
5.
J Med Microbiol ; 70(7)2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34309502

RESUMO

Introduction. Shiga toxin-producing Escherichia coli (STEC) can cause severe disease and large outbreaks. In England, the incidence and clinical significance of STEC serogroups other than O157 (non-O157) is unknown due to a testing bias for detection of STEC O157. Since 2013, the implementation of PCR to detect all STEC serogroups by an increasing number of diagnostic laboratories has led to an increase in the detection of non-O157 STEC.Hypothesis/Gap statement. Due to a bias in testing methodologies to select for STEC serogroup O157 in frontline diagnostic laboratories in most countries, very little surveillance data have been previously generated on non-O157 STEC.Aim. Five years (2014-2018) of STEC national surveillance data were extracted and descriptive analysis undertaken to assess disease severity of non-O157 STEC strains.Methods. Data from 1 January 2014 to 31 December 2018 were extracted from the National Enhanced Surveillance System for STEC and analysed.Results. The implementation of Gastrointestinal Polymerase Chain Reaction (GI-PCR) has resulted in a four-fold increase in the detection of non-O157 STEC cases between 2014 and 2018. There were 2579 cases infected with 97 different non-O157 serogroups. The gender distribution was similar amongst STEC O157 and non-O157 STEC cases with 57 and 56 % of cases being female respectively, but a significantly higher proportion of cases (P <0.001) under 5 years of age was observed among STEC O157 (22 %) cases compared to non-O157 STEC (14 %). The most common non-O157 serogroups were O26 (16 %), O146 (11 %), O91 (10 %), O128 (7 %), O103 (5 %) and O117 (3 %). Overall, rates of bloody diarrhoea were highest in O26 (44 %) and O103 (48 %) cases and lowest in STEC O117 cases (17 %). Strains harbouring Shiga toxin stx1a caused the highest proportion of diarrhoea (93 %) and caused the same level of bloody diarrhoea as stx2a (39 %). However, stx2a caused the highest proportion of vomiting (46 %), hospitalisation (49 %) and considerably more HUS (29 %) than other stx profiles.Conclusion. The implementation of PCR targeting stx at diagnostic laboratories has shown that non-O157 STEC, most notably STEC O26, are an emerging risk to public health.


Assuntos
Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli Shiga Toxigênica/isolamento & purificação , Adolescente , Adulto , Distribuição por Idade , Criança , Pré-Escolar , Inglaterra/epidemiologia , Feminino , Humanos , Masculino , Técnicas de Diagnóstico Molecular , Reação em Cadeia da Polimerase , Sorogrupo , Distribuição por Sexo , Toxina Shiga I/genética , Toxina Shiga II/genética , Escherichia coli Shiga Toxigênica/classificação , Escherichia coli Shiga Toxigênica/genética , Escherichia coli Shiga Toxigênica/patogenicidade , Virulência/genética , Adulto Jovem
6.
Transfusion ; 61 Suppl 1: S80-S89, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34269444

RESUMO

BACKGROUND: Collection of non-leukoreduced citrate-phosphate-dextrose-adenine (CPDA-1) whole blood is performed in walking blood banks. Blood collected under field conditions may have increased risk of bacterial contamination. This study was conducted to examine the effects of WBC reduction and storage temperature on growth of Escherichia coli (ATCC® 25922™) in CPDA-1 whole blood. METHODS: CPDA-1 whole blood of 450 ml from 10 group O donors was inoculated with E. coli. Two hours after inoculation, the test bags were leukoreduced with a platelet-sparing filter. The control bags remained unfiltered. Each whole blood bag was then split into three smaller bags for further storage at 2-6°C, 20-24°C, or 33-37°C. Bacterial growth was quantified immediately, 2 and 3 h after inoculation, on days 1, 3, 7, and 14 for all storage temperatures, and on days 21 and 35 for storage at 2-6°C. RESULTS: Whole blood was inoculated with a median of 19.5 (range 12.0-32.0) colony-forming units per ml (CFU/ml) E. coli. After leukoreduction, a median of 3.3 CFU/ml (range 0.0-33.3) E. coli remained. In the control arm, the WBCs phagocytized E. coli within 24 h at 20-24°C and 33-37°C in 9 of 10 bags. During storage at 2-6°C, a slow self-sterilization occurred over time with and without leukoreduction. CONCLUSIONS: Storage at 20-24°C and 33-37°C for up to 24 h before leukoreduction reduces the risk of E. coli-contamination in CPDA-1 whole blood. Subsequent storage at 2-6°C will further reduce the growth of E. coli.


Assuntos
Preservação de Sangue , Segurança do Sangue , Infecções por Escherichia coli/microbiologia , Escherichia coli/crescimento & desenvolvimento , Procedimentos de Redução de Leucócitos , Adenina/química , Preservação de Sangue/métodos , Citratos/química , Escherichia coli/isolamento & purificação , Glucose/química , Humanos , Temperatura
7.
Zool Res ; 42(4): 461-468, 2021 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-34156173

RESUMO

During a 2018 antimicrobial resistance surveillance of Escherichia coli isolates from diarrheal calves in Xinjiang Province, China, an unexpectedly high prevalence (48.5%) of fosfomycin resistance was observed. This study aimed to reveal the determinants of fosfomycin resistance and the underlying transmission mechanism. Polymerase chain reaction (PCR) screening showed that all fosfomycin-resistant E. coli carried the fosA3 gene. Pulsed-field gel electrophoresis (PFGE) and southern blot hybridization revealed that the 16 fosA3-positive isolates belonged to four different PFGE patterns (i.e., A, B, C, D). The fosA3 genes of 11 clonally related strains (pattern D) were located on the chromosome, while others were carried by plasmids. Whole-genome and long-read sequencing indicated that the pattern D strains were E. coli O101: H9-ST10, and the pattern C, B, and A strains were O101: H9-ST167, O8: H30-ST1431, and O101: H9 with unknown ST, respectively. Among the pattern C strains, the bla CTX-M-14 gene was co-localized with the fosA3 gene on the F18: A-: B1 plasmids. Interestingly, phylogenetic analysis based on core genome single nucleotide polymorphisms (cgSNPs) showed that the O101: H9-ST10 strains were closely related to a Australian-isolated Chroicocephalus-origin E. coli O101: H9-ST10 strain producing CTX-M-14 and FosA3, with a difference of only 11 SNPs. These results indicate possible international dissemination of the high-risk E. coli clone O101: H9-ST10 by migratory birds.


Assuntos
Doenças dos Bovinos/microbiologia , Charadriiformes/microbiologia , Diarreia/veterinária , Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/metabolismo , Escherichia coli/classificação , Migração Animal , Animais , Antibacterianos/farmacologia , Austrália , Bovinos , Doenças dos Bovinos/epidemiologia , China/epidemiologia , Diarreia/epidemiologia , Diarreia/microbiologia , Farmacorresistência Bacteriana , Escherichia coli/genética , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , beta-Lactamases/genética
8.
Epidemiol Infect ; 149: e147, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34096488

RESUMO

In August 2019, public health surveillance systems in Scotland and England identified seven, geographically dispersed cases infected with the same strain (defined as isolates that fell within the same five single nucleotide polymorphism single linage cluster) of Shiga toxin-producing Escherichia coli O157:H7. Epidemiological analysis of enhanced surveillance questionnaire data identified handling raw beef and shopping from the same national retailer (retailer A) as the common exposure. Concurrently, a microbiological survey of minced beef at retail identified the same strain in a sample of minced beef sold by retailer A, providing microbiological evidence of the link. Between September and November 2019, a further four primary and two secondary cases infected with the same strain were identified; two cases developed haemolytic uraemic syndrome. None of the four primary cases reported consumption of beef from retailer A and the transmission route of these subsequent cases was not identified, although all four primary cases visited the same petting farm. Generally, outbreaks of STEC O157:H7 in the UK appear to be distinct, short-lived events; however, on-going transmission linked to contaminated food, animals or environmental exposures and person-to-person contact do occur. Although outbreaks of STEC caused by contaminated fresh produce are increasingly common, undercooked meat products remain a risk of infection.


Assuntos
Surtos de Doenças , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/transmissão , Escherichia coli O157/isolamento & purificação , Doenças Transmitidas por Alimentos/microbiologia , Adolescente , Adulto , Animais , Bovinos , Criança , Pré-Escolar , DNA Bacteriano/genética , Inglaterra/epidemiologia , Monitoramento Epidemiológico , Infecções por Escherichia coli/epidemiologia , Escherichia coli O157/classificação , Escherichia coli O157/genética , Feminino , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/epidemiologia , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Filogenia , Carne Vermelha/microbiologia , Escócia/epidemiologia , Adulto Jovem
9.
Nucleic Acids Res ; 49(13): 7375-7388, 2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-34181709

RESUMO

DNA methylation is a common epigenetic mark that influences transcriptional regulation, and therefore cellular phenotype, across all domains of life. In particular, both orphan methyltransferases and those from phasevariable restriction modification systems (RMSs) have been co-opted to regulate virulence epigenetically in many bacteria. We now show that three distinct non-phasevariable Type I RMSs in Escherichia coli have no measurable impact on gene expression, in vivo virulence, or any of 1190 in vitro growth phenotypes. We demonstrated this using both Type I RMS knockout mutants as well as heterologous installation of Type I RMSs into two E. coli strains. These data provide three clear and currently rare examples of restriction modification systems that have no impact on their host organism's gene regulation. This leads to the possibility that other such nonregulatory methylation systems may exist, broadening our view of the potential role that RMSs may play in bacterial evolution.


Assuntos
Metilação de DNA , Enzimas de Restrição-Modificação do DNA , Escherichia coli/genética , Animais , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Regulação Bacteriana da Expressão Gênica , Camundongos , Infecções Urinárias/microbiologia , Escherichia coli Uropatogênica/genética , Escherichia coli Uropatogênica/crescimento & desenvolvimento , Escherichia coli Uropatogênica/metabolismo , Escherichia coli Uropatogênica/patogenicidade
10.
ACS Appl Mater Interfaces ; 13(23): 26800-26807, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34096255

RESUMO

Catalytic conversion of hydrogen peroxide (H2O2) to more toxic hydroxyl radicals (•OH) is a good choice for sterilization and anti-infection, but endogenous H2O2 is insufficient to achieve satisfactory sterilization efficacy. Despite great efforts, designing and developing antimicrobial materials that specifically and effectively self-supply H2O2 at the wound site remain as tremendous challenges. Here, we report a pH-responsive copper peroxide-loaded wound dressing made from copper hydroxide and gelatin sponge and then reacted with H2O2. In vitro experiments show that the prepared wound dressing has good bactericidal properties against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa). Moreover, the as-prepared wound dressing can release •OH specifically in the bacterial-infected skin wound, rather than in normal tissues, and in vivo skin wound-healing experiments proved that the synthesized copper peroxide-loaded gelatin sponge could combat E. coli effectively; in addition, Cu2+ released from the gelatin sponge could stimulate angiogenesis and collagen deposition simultaneously. The study provides a strategy to improve antibacterial efficacy and reduce the toxic side effects through the release of •OH by bacterial self-activation.


Assuntos
Antibacterianos/farmacologia , Cobre/farmacologia , Infecções por Escherichia coli/tratamento farmacológico , Gelatina/química , Peróxidos/farmacologia , Pele/efeitos dos fármacos , Cicatrização/efeitos dos fármacos , Infecção dos Ferimentos/tratamento farmacológico , Animais , Antibacterianos/química , Bandagens , Cobre/química , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Peróxidos/química , Infecção dos Ferimentos/microbiologia
11.
Ann Agric Environ Med ; 28(2): 271-276, 2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34184510

RESUMO

INTRODUCTION: The article discusses the antimicrobial resistance of poultry-isolated bacteria in the Wielkopolska region of Poland. MATERIAL AND METHODS: From August 2014 - June 2016, antibiotic resistance screening tests were performed involving 4,496 samples of Escherichia coli and 84 samples of Klebsiella spp., and the following antibiotics: amoxicillin, amoxicillin with clavulanic acid, colistin, doxycycline, enrofloxacin, florfenicol, neomycin, norfloxacin, spectinomycin, and trimethoprim with sulfamethoxazole. The research used broth the microdilution method and CLSI standards. RESULTS: During the investigation period of 22 months a growing percentage of E. coli isolates showed antibiotic resistance to amoxicillin, amoxicillin with clavulanic acid, colistin, enrofloxacin, neomycin, norfloxacin, spectinomycin, and trimethoprim with sulfamethoxazole. Resistance to doxycycline and florfenicol decreased. The most efficient antibiotics against E. coli were colistin (84.64 %), neomycin (80.62 %), and amoxicillin with clavulanic acid (73.05 %). Klebsiella samples were the most susceptible to neomycin (85.71 %), colistin (84.52 %), and trimethoprim with sulfamethoxazole (73.81 %). CONCLUSIONS: Antibiotic resistance of pathogenic micro-organisms, such as Escherichia coli and Klebsiella spp., is a serious problem both for poultry producers and for public health protection. Low efficiency of numerous antibiotic groups forces reflection on limiting the use of medicines in food-producing animals.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Infecções por Enterobacteriaceae/veterinária , Infecções por Escherichia coli/veterinária , Escherichia coli/efeitos dos fármacos , Klebsiella/efeitos dos fármacos , Doenças das Aves Domésticas/microbiologia , Animais , Galinhas/microbiologia , Infecções por Enterobacteriaceae/microbiologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Klebsiella/genética , Klebsiella/isolamento & purificação , Testes de Sensibilidade Microbiana , Polônia
12.
Int J Mol Sci ; 22(9)2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066555

RESUMO

Traditional antimicrobial treatments consist of drugs which target different essential functions in pathogens. Nevertheless, bacteria continue to evolve new mechanisms to evade this drug-mediated killing with surprising speed on the deployment of each new drug and antibiotic worldwide, a phenomenon called antimicrobial resistance (AMR). Nowadays, AMR represents a critical health threat, for which new medical interventions are urgently needed. By 2050, it is estimated that the leading cause of death will be through untreatable AMR pathogens. Although antibiotics remain a first-line treatment, non-antibiotic therapies such as prophylactic vaccines and therapeutic monoclonal antibodies (mAbs) are increasingly interesting alternatives to limit the spread of such antibiotic resistant microorganisms. For the discovery of new vaccines and mAbs, the search for effective antigens that are able to raise protective immune responses is a challenging undertaking. In this context, outer membrane vesicles (OMV) represent a promising approach, as they recapitulate the complete antigen repertoire that occurs on the surface of Gram-negative bacteria. In this review, we present Escherichia coli and Pseudomonas aeruginosa as specific examples of key AMR threats caused by Gram-negative bacteria and we discuss the current status of mAbs and vaccine approaches under development as well as how knowledge on OMV could benefit antigen discovery strategies.


Assuntos
Farmacorresistência Bacteriana , Escherichia coli/fisiologia , Pseudomonas aeruginosa/fisiologia , Animais , Vacinas Bacterianas/imunologia , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/microbiologia , Humanos , Infecções por Pseudomonas/epidemiologia , Infecções por Pseudomonas/imunologia , Infecções por Pseudomonas/microbiologia
13.
BMC Infect Dis ; 21(1): 578, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34130629

RESUMO

BACKGROUND: Antibiotic Resistance is an imminent global public health threat. Antibiotic resistance emerged in healthcare settings and has now moved on to the community settings. This study was conducted to identify the rates of asymptomatic colonization with selected antibiotic resistant organisms, (Methicillin Resistant Staphylococcus aureus (MRSA), Extended Spectrum Beta Lactamase (ESBL) producing Escherichia coli and Klebsiella spp and carbapenem resistant E.coli and Klebsiella spp) - among a group of university students in Sri Lanka. Identification of genetic determinants of MRSA and ESBL was an additional objective of the study. METHODS: A self - collected nasal swab and a peri-rectal swab collected after passing stools were obtained. Routine microbiological methods were used for the isolation S.aureus from the nasal swab and E.coli and Klebsiella species from the peri-rectal swab. Antibiotic sensitivity testing was performed as recommended by clinical and laboratory standard institute (CLSI). Three (3) genes that are responsible for ESBL production; blaCTX-M, blaSHV, and blaTEM were tested using previously described primers and PCR procedures. Identification of MecA and PVL genes attributed to MRSA was also done with PCR. RESULTS: A total of 322 participants between 21 and 28 years were recruited representing 5 different faculties of study. Seventy one (22.0%) were colonized with S.aureus and 14 among them with MRSA, making the MRSA colonization rate of 4.3%. Forty five (15%) of the participants were colonized with an ESBL producing E.coli or Klebsiella spp. No one was colonized with carbapenem resistant E.coli or Klebsiella species. Of the 45 ESBL producers the commonest genetic determinant identified was blaCTX-M (n = 36), while 16 isolates had blaTEM and 7 had blaSHV. Similarly, of the 14 isolates identified as MRSA, 3 (21.4%) were found to be PVL positive while 11 (78.6%) were MecA positive. CONCLUSIONS: A high rate of colonization with ESBL producing E.coli and Klebsiella species was noted in our study group.


Assuntos
Antibacterianos/uso terapêutico , Infecções Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , Farmacorresistência Bacteriana , Universidades , Adulto , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Carbapenêmicos/uso terapêutico , Estudos de Coortes , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Feminino , Humanos , Klebsiella/isolamento & purificação , Infecções por Klebsiella/microbiologia , Masculino , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Sri Lanka , Infecções Estafilocócicas/microbiologia , Estudantes , Adulto Jovem , beta-Lactamases/genética
14.
J Biol Chem ; 296: 100795, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34019876

RESUMO

Pyridoxal 5'-phosphate (PLP), the catalytically active form of vitamin B6, plays a pivotal role in metabolism as an enzyme cofactor. PLP is a very reactive molecule and can be very toxic unless its intracellular concentration is finely regulated. In Escherichia coli, PLP formation is catalyzed by pyridoxine 5'-phosphate oxidase (PNPO), a homodimeric FMN-dependent enzyme that is responsible for the last step of PLP biosynthesis and is also involved in the PLP salvage pathway. We have recently observed that E. coli PNPO undergoes an allosteric feedback inhibition by PLP, caused by a strong allosteric coupling between PLP binding at the allosteric site and substrate binding at the active site. Here we report the crystallographic identification of the PLP allosteric site, located at the interface between the enzyme subunits and mainly circumscribed by three arginine residues (Arg23, Arg24, and Arg215) that form an "arginine cage" and efficiently trap PLP. The crystal structure of the PNPO-PLP complex, characterized by a marked structural asymmetry, presents only one PLP molecule bound at the allosteric site of one monomer and sheds light on the allosteric inhibition mechanism that makes the enzyme-substrate-PLP ternary complex catalytically incompetent. Site-directed mutagenesis studies focused on the arginine cage validate the identity of the allosteric site and provide an effective means to modulate the allosteric properties of the enzyme, from the loosening of the allosteric coupling (in the R23L/R24L and R23L/R215L variants) to the complete loss of allosteric properties (in the R23L/R24L/R21L variant).


Assuntos
Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Fosfato de Piridoxal/metabolismo , Piridoxaminafosfato Oxidase/metabolismo , Sítio Alostérico , Cristalografia por Raios X , Escherichia coli/química , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/química , Humanos , Modelos Moleculares , Conformação Proteica , Piridoxaminafosfato Oxidase/química
15.
Infect Immun ; 89(8): e0011521, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-33941580

RESUMO

Comparative genomics of bacterial pathogens has been useful for revealing potential virulence factors. Escherichia coli is a significant cause of human morbidity and mortality worldwide but can also exist as a commensal in the human gastrointestinal tract. With many sequenced genomes, it has served as a model organism for comparative genomic studies to understand the link between genetic content and potential for virulence. To date, however, no comprehensive analysis of its complete "virulome" has been performed for the purpose of identifying universal or pathotype-specific targets for vaccine development. Here, we describe the construction of a pathotype database of 107 well-characterized completely sequenced pathogenic and nonpathogenic E. coli strains, which we annotated for major virulence factors (VFs). The data are cross referenced for patterns against pathotype, phylogroup, and sequence type, and the results were verified against all 1,348 complete E. coli chromosomes in the NCBI RefSeq database. Our results demonstrate that phylogroup drives many of the "pathotype-associated" VFs, and ExPEC-associated VFs are found predominantly within the B2/D/F/G phylogenetic clade, suggesting that these phylogroups are better adapted to infect human hosts. Finally, we used this information to propose polyvalent vaccine targets with specificity toward extraintestinal strains, targeting key invasive strategies, including immune evasion (group 2 capsule), iron acquisition (FyuA, IutA, and Sit), adherence (SinH, Afa, Pap, Sfa, and Iha), and toxins (Usp, Sat, Vat, Cdt, Cnf1, and HlyA). While many of these targets have been proposed before, this work is the first to examine their pathotype and phylogroup distribution and how they may be targeted together to prevent disease.


Assuntos
Infecções por Escherichia coli/microbiologia , Escherichia coli/genética , Genoma Bacteriano , Genômica , Animais , Vacinas Bacterianas/imunologia , Escherichia coli/patogenicidade , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/prevenção & controle , Proteínas de Escherichia coli/genética , Escherichia coli Extraintestinal Patogênica/genética , Genes Bacterianos , Humanos , Vacinas Combinadas/imunologia , Virulência/genética , Fatores de Virulência/genética
16.
Appl Environ Microbiol ; 87(14): e0312120, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-33962981

RESUMO

Enterotoxigenic Escherichia coli (ETEC) and Shiga toxin-producing E. coli (STEC) strains are the causative agents of severe foodborne diseases in both humans and animals. In this study, porcine pathogenic E. coli strains (n = 277) as well as porcine commensal strains (n = 188) were tested for their susceptibilities to 34 bacteriocin monoproducers to identify the most suitable bacteriocin types inhibiting porcine pathogens. Under in vitro conditions, the set of pathogenic E. coli strains was found to be significantly more susceptible to the majority of tested bacteriocins than commensal E. coli. Based on the production of bacteriocins with specific activity against pathogens, three potentially probiotic commensal E. coli strains of human origin were selected. These strains were found to be able to outcompete ETEC strains expressing F4 or F18 fimbriae in liquid culture and also decreased the severity and duration of diarrhea in piglets during experimental ETEC infection as well as pathogen numbers on the last day of in vivo experimentation. While the extents of the probiotic effect were different for each strain, the cocktail of all three strains showed the most pronounced beneficial effects, suggesting synergy between the tested E. coli strains. IMPORTANCE Increasing levels of antibiotic resistance among bacteria also increase the need for alternatives to conventional antibiotic treatment. Pathogenic Escherichia coli represents a major diarrheic infectious agent of piglets in their postweaning period; however, available measures to control these infections are limited. This study describes three novel E. coli strains producing antimicrobial compounds (bacteriocins) that actively inhibit a majority of toxigenic E. coli strains. The beneficial effect of three potentially probiotic E. coli strains was demonstrated under both in vitro and in vivo conditions. The novel probiotic candidates may be used as prophylaxis during piglets' postweaning period to overcome common infections caused by E. coli.


Assuntos
Toxinas Bacterianas , Bacteriocinas/uso terapêutico , Infecções por Escherichia coli/prevenção & controle , Escherichia coli , Probióticos/uso terapêutico , Doenças dos Suínos/prevenção & controle , Animais , Toxinas Bacterianas/metabolismo , Bacteriocinas/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/veterinária , Fezes/microbiologia , Suínos , Doenças dos Suínos/microbiologia , Fatores de Virulência/genética
17.
Anal Bioanal Chem ; 413(17): 4417-4426, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34013400

RESUMO

Simple and visual quantitative detection of foodborne pathogens can effectively reduce the outbreaks of foodborne diseases. Herein, we developed a simple and sensitive quantum dot (QD)-based paper device for visual and quantitative detection of Escherichia coli (E. coli) O157:H7 based on immunomagnetic separation and nanoparticle dissolution-triggered signal amplification. In this study, E. coli O157:H7 was magnetically separated and labeled with silver nanoparticles (AgNPs), and the AgNP labels can be converted into millions of Ag ions, which subsequently quench the fluorescence of QDs in the paper strip, which along with the readout can be visualized and quantified by the change in length of fluorescent quenched band. Owing to the high capture efficiency and effective signal amplification, as low as 500 cfu mL-1 of E. coli O157:H7 could be easily detected by naked eyes. Furthermore, this novel platform was successfully applied to detect E. coli O157:H7 in spiked milk samples with good accuracy, indicating its potential in the detection of foodborne pathogens in real samples.


Assuntos
Escherichia coli O157/isolamento & purificação , Corantes Fluorescentes/análise , Separação Imunomagnética/instrumentação , Pontos Quânticos/análise , Fitas Reagentes/análise , Animais , Infecções por Escherichia coli/microbiologia , Contaminação de Alimentos/análise , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Nanopartículas Metálicas/química , Leite/microbiologia , Papel , Prata/química
18.
Am J Physiol Cell Physiol ; 321(1): C134-C146, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33979212

RESUMO

The local environment forces a selection of bacteria that might invade the urinary tract, allowing only the most virulent to access the kidney. Quite similar to the diet in setting the stage for the gut microbiome, renal function determines the conditions for bacteria-host interaction in the urinary tract. In the kidney, the term local environment or microenvironment is completely justified because the environment literally changes within a few micrometers. The precise composition of the urine is a function of the epithelium lining the microdomain, and the microenvironment in the kidney shows more variation in the content of nutrients, ion composition, osmolality, and pH than any other site of bacteria-host interaction. This review will cover some of the aspects of bacterial-host interaction in this unique setting and how uropathogenic bacteria can alter the condition for bacteria-host interaction. There will be a particular focus on the recent findings regarding how bacteria specifically trigger host paracrine signaling, via release of extracellular ATP and activation of P2 purinergic receptors. These finding will be discussed from the perspective of severe urinary tract infections, including pyelonephritis and urosepsis.


Assuntos
Infecções por Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas Hemolisinas/genética , Pielonefrite/genética , Receptores Purinérgicos P2/genética , Sepse/genética , Infecções Urinárias/genética , Escherichia coli Uropatogênica/genética , Trifosfato de Adenosina/metabolismo , Anoctamina-1/genética , Anoctamina-1/metabolismo , Infecções por Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/patologia , Proteínas de Escherichia coli/metabolismo , Regulação da Expressão Gênica , Proteínas Hemolisinas/metabolismo , Interações Hospedeiro-Patógeno/genética , Humanos , Concentração de Íons de Hidrogênio , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Comunicação Parácrina , Pielonefrite/metabolismo , Pielonefrite/microbiologia , Pielonefrite/patologia , Receptores Purinérgicos P2/metabolismo , Sepse/metabolismo , Sepse/microbiologia , Sepse/patologia , Transdução de Sinais , Infecções Urinárias/metabolismo , Infecções Urinárias/microbiologia , Infecções Urinárias/patologia , Escherichia coli Uropatogênica/crescimento & desenvolvimento , Escherichia coli Uropatogênica/metabolismo , Escherichia coli Uropatogênica/patogenicidade
19.
Commun Biol ; 4(1): 521, 2021 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-33953333

RESUMO

Many bacterial species and antibiotic classes exhibit heteroresistance, a phenomenon in which a susceptible bacterial isolate harbors a resistant subpopulation that can grow in the presence of an antibiotic and cause treatment failure. The resistant phenotype is often unstable and without antibiotic selection it reverts back to susceptibility. Here we studied the dynamics by which these resistant subpopulations are enriched in the presence of antibiotic and recede back to their baseline frequency in the absence of selection. An increasing understanding of this instability will allow more effective diagnostics and treatment of infections caused by heteroresistant bacteria. We show for clinical isolates of Escherichia coli and Salmonella enterica that different antibiotics at levels below the MIC of the susceptible main population can cause rapid enrichment of resistant subpopulations with increased copy number of genes that cause resistance. Modelling and growth rate measurements of bacteria with increased gene copy number in cultures and by microscopy of single-cells in a microfluidic chip show that the fitness cost of gene amplifications and their intrinsic instability drives their rapid loss in the absence of selection. Using a common antibiotic susceptibility test, we demonstrate that this test strongly underestimates the occurrence of heteroresistance in clinical isolates.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Escherichia coli/diagnóstico , Escherichia coli/crescimento & desenvolvimento , Infecções por Salmonella/diagnóstico , Salmonella enterica/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/genética , Infecções por Escherichia coli/microbiologia , Regulação Bacteriana da Expressão Gênica , Humanos , Testes de Sensibilidade Microbiana , Infecções por Salmonella/genética , Infecções por Salmonella/microbiologia , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/isolamento & purificação
20.
Epidemiol Infect ; 149: e124, 2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-33955833

RESUMO

In August 2017, a cluster of four persons infected with genetically related strains of Shiga toxin-producing Escherichia coli (STEC) O157:H7 was identified. These strains possessed the Shiga toxin (stx) subtype stx2a, a toxin type known to be associated with severe clinical outcome. One person died after developing haemolytic uraemic syndrome. Interviews with cases revealed that three of the cases had been exposed to dogs fed on a raw meat-based diet (RMBD), specifically tripe. In two cases, the tripe had been purchased from the same supplier. Sampling and microbiological screening of raw pet food was undertaken and indicated the presence of STEC in the products. STEC was isolated from one sample of raw tripe but was different from the strain causing illness in humans. Nevertheless, the detection of STEC in the tripe provided evidence that raw pet food was a potential source of human STEC infection during this outbreak. This adds to the evidence of raw pet food as a risk factor for zoonotic transmission of gastrointestinal pathogens, which is widely accepted for Salmonella, Listeria and Campylobacter spp. Feeding RMBD to companion animals has recently increased in popularity due to the belief that they provide health benefits to animals. Although still rare, an increase in STEC cases reporting exposure to RMBDs was detected in 2017. There has also been an increased frequency of raw pet food incidents in 2017, suggesting an increasing trend in potential risk to humans from raw pet food. Recommendations to reduce the risk of infection included improved awareness of risk and promotion of good hygiene practices among the public when handling raw pet food.


Assuntos
Infecções por Escherichia coli/microbiologia , Escherichia coli O157/isolamento & purificação , Animais de Estimação , Alimentos Crus/microbiologia , Animais , Dieta/veterinária , Surtos de Doenças , Cães , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/transmissão , Escherichia coli O157/genética , Manipulação de Alimentos , Microbiologia de Alimentos , Síndrome Hemolítico-Urêmica/epidemiologia , Síndrome Hemolítico-Urêmica/microbiologia , Humanos , Carne/microbiologia , Toxina Shiga/genética , Zoonoses/epidemiologia , Zoonoses/microbiologia , Zoonoses/transmissão
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