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Rebelo A, Mourão J, Freitas AR, Duarte B, Silveira E, Sanchez-Valenzuela A, Almeida A, Baquero F, Coque TM, Peixe L, Antunes P, Novais C. Diversity of metal and antibiotic resistance genes in Enterococcus spp. from the last century reflects multiple pollution and genetic exchange among phyla from overlapping ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 787:147548. [PMID: 34000557 DOI: 10.1016/j.scitotenv.2021.147548] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 04/26/2021] [Accepted: 04/30/2021] [Indexed: 06/12/2023]
Abstract
Arsenic (As), mercury (Hg), and copper (Cu) are among the major historical and contemporary metal pollutants linked to global anthropogenic activities. Enterococcus have been considered indicators of fecal pollution and antibiotic resistance for years, but its largely underexplored metallome precludes understanding their role as metal pollution bioindicators as well. Our goal was to determine the occurrence, diversity, and phenotypes associated with known acquired genes/operons conferring tolerance to As, Hg or Cu among Enterococcus and to identify their genetic context (381 field isolates from diverse epidemiological and genetic backgrounds; 3547 enterococcal genomes available in databases representing a time span during 1900-2019). Genes conferring tolerance to As (arsA), Hg (merA) or Cu (tcrB) were used as biomarkers of widespread metal tolerance operons. Different variants of metal tolerance (MeT) genes (13 arsA, 6 merA, 1 tcrB) were more commonly recovered from the food-chain (arsA, tcrB) or humans (merA), and were shared with 49 other bacterial taxa. Comparative genomics analysis revealed that MeT genes occurred in heterogeneous operons, at least since the 1900s, with an increasing accretion of antibiotic resistance genes since the 1960's, reflecting diverse antimicrobial pollution. Multiple MeT genes were co-located on the chromosome or conjugative plasmids flanked by elements with high potential for recombination, often along with antibiotic resistance genes. Phenotypic analysis of some isolates carrying MeT genes revealed up to 128× fold increase in the minimum inhibitory concentrations to metals. The main distribution of functional MeT genes among Enterococcus faecium and Enterococcus faecalis from different sources, time spans, and clonal lineages, and their ability to acquire diverse genes from multiple taxa bacterial communities places these species as good candidates to be used as model organisms in future projects aiming at the identification and quantification of bioindicators of metal polluted environments by anthropogenic activities.
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Affiliation(s)
- Andreia Rebelo
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Portugal; Área Técnico-científica de Saúde Ambiental, Escola Superior de Saúde, Instituto Politécnico do Porto, Portugal
| | - Joana Mourão
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Centro de Neurociências e Biologia Celular, Universidade de Coimbra, Portugal; Centro de Inovação em Biomedicina e Biotecnologia, Universidade de Coimbra, Portugal; Instituto de Investigação Interdisciplinar, Universidade de Coimbra, Portugal
| | - Ana R Freitas
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal
| | - Bárbara Duarte
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal
| | - Eduarda Silveira
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Centro de Investigação Vasco da Gama (CIVG), Departamento de Ciências Veterinárias, Escola Universitária Vasco da Gama, Coimbra, Portugal; Faculdade de Farmácia, Universidade de Coimbra, Portugal
| | - Antonio Sanchez-Valenzuela
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Servicio de Microbiologia, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Agostinho Almeida
- LAQV/REQUIMTE, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto, Portugal
| | - Fernando Baquero
- Servicio de Microbiologia, Hospital Universitario Ramón y Cajal, Madrid, Spain; Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Madrid, Spain; Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Teresa M Coque
- Servicio de Microbiologia, Hospital Universitario Ramón y Cajal, Madrid, Spain; Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Madrid, Spain; Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Luísa Peixe
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal
| | - Patrícia Antunes
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Portugal
| | - Carla Novais
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal.
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Niemi M, Falkenberg T, Petzold M, Chuc NTK, Patel V. Symptoms of antenatal common mental disorders, preterm birth and low birthweight: a prospective cohort study in a semi-rural district of Vietnam. Trop Med Int Health 2013; 18:687-95. [PMID: 23590183 DOI: 10.1111/tmi.12101] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To examine the association of low birthweight (LBW) and prematurity with clinically significant symptoms of antenatal common mental disorders (ACMDs) during the third trimester of pregnancy in a semi-rural area in Vietnam. METHODS Prospective community-based cohort study. Severity of ACMD symptoms was assessed with the Edinburgh Depression Scale, low birthweight was defined as below 2500 g, and gestational age was estimated according to last menstrual period. Reproductive and socio-demographic risk factors were measured as potential confounders of the association between ACMD and the outcomes. We conducted bivariate analyses of association between ACMD and the perinatal outcomes, employing chi-square tests, crude odds ratios and 95% confidence intervals. Multiple logistic regression analysis was used to adjust for confounding. FINDINGS We found a prevalence of clinically significant symptoms of ACMDs of 37.4%, which were significantly associated with preterm birth (adjusted OR 1.98, CI95% = 1.14-3.43) and low birthweight (adjusted OR 2.24, CI95% = 1.02-4.95). Among the examined risk factors for the outcome measures, only maternal age was found to be statistically significant for low birthweight and preterm birth. CONCLUSIONS This study confirms that clinically significant symptom levels of ACMD in Vietnam are associated with preterm birth and low birthweight. These findings highlight the importance of cost-effective public health interventions for ACMD in Vietnam and further exploration of its physiological link with preterm birth and low birthweight.
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Affiliation(s)
- Maria Niemi
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
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da Silva VL, Caçador NC, da Silva CDSF, Fontes CO, Garcia GD, Nicoli JR, Diniz CG. Occurrence of multidrug-resistant and toxic-metal tolerant enterococci in fresh feces from urban pigeons in Brazil. Microbes Environ 2012; 27:179-85. [PMID: 22791051 PMCID: PMC4036010 DOI: 10.1264/jsme2.me11296] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Enterococcus are emerging as important putative pathogens resistant to chemicals that are widely released into the environment, and urban pigeons might act as a natural reservoir contributing to the spread of resistant strains. This study aimed to evaluate the occurrence of Enterococcus in pigeon feces and their antimicrobial and toxic metal susceptibility. Bacteria were isolated and identified from 150 fresh feces by phenotypic and genetic techniques. Antimicrobial and toxic metal susceptibility was determined by the agar dilution method, and the multiple antibiotic resistance index (MAR) was calculated. Out of 120 isolates, no resistance was observed against penicillin and vancomycin, but was observed against gentamicin (55.8%), chloramphenicol (21.7%), tetracycline (13.3%), ciprofloxacin (8.4%) and rifampin (2.5%). 18.3% presented a MAR index ≥0.2, ranging between 0.14 to 0.57, indicating resistance to more than one antimicrobial. All samples were tolerant to >1024 μg mL−1 zinc and chromium. Minimal inhibitory concentration (MIC) of 1,024 μg mL−1 was observed for copper (100%) and nickel (71.4%). Mercury inhibited 88.4% at 32 μg mL−1 and the MIC for cadmium ranged from 0.125–128 μg mL−1. Since pigeons were found to harbor drug-resistant Enterococcus, our data support that their presence in the urban environment may contribute to the spread of resistance, with an impact on public health.
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Affiliation(s)
- Vânia Lúcia da Silva
- Department of Parasitology, Microbiology and Immunology, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, Brazil.
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Roberts MC. Antibiotic resistance mechanisms in bacteria of oral and upper respiratory origin. Int J Antimicrob Agents 1998; 9:255-67. [PMID: 9573495 DOI: 10.1016/s0924-8579(98)00005-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Over the past 20 years, antibiotic resistance has increased in virtually every species of bacteria examined. In this paper, the main mechanisms of antibiotic resistance currently known for antibiotics used for treatment of disease caused by oral and upper respiratory bacteria will be reviewed, with an emphasis on the most commonly used antibiotics. The possible role that mercury, which is released from silver amalgams, plays in the oral/respiratory bacterial ecology is also discussed, as it relates to possible selection of antibiotic resistant bacteria.
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Affiliation(s)
- M C Roberts
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle 98195-7238, USA.
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Wireman J, Liebert CA, Smith T, Summers AO. Association of mercury resistance with antibiotic resistance in the gram-negative fecal bacteria of primates. Appl Environ Microbiol 1997; 63:4494-503. [PMID: 9361435 PMCID: PMC168768 DOI: 10.1128/aem.63.11.4494-4503.1997] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Gram-negative fecal bacterial from three longitudinal Hg exposure experiments and from two independent survey collections were examined for their carriage of the mercury resistance (mer) locus. The occurrence of antibiotic resistance was also assessed in both mercury-resistant (Hgr) and mercury-susceptible (Hgs) isolates from the same collections. The longitudinal studies involved exposure of the intestinal flora to Hg released from amalgam "silver" dental restorations in six monkeys. Hgr strains were recovered before the installation of amalgams, and frequently these became the dominant strains while amalgams were installed. Such persistent Hgr strains always carried the same mer locus throughout the experiments. In both the longitudinal and survey collections, certain mer loci were preferentially associated with one genus, whereas other mer loci were recovered from many genera. In general, strains with any mer locus were more likely to be multiresistant than were strains without mer loci; this clustering tendency was also seen for antibiotic resistance genes. However, the association of antibiotic multiresistance with mer loci was not random; regardless of source, certain mer loci occurred in highly multiresistant strains (with as many as seven antibiotic resistances), whereas other mer loci were found in strains without any antibiotic resistance. The majority of highly multiresistant Hgr strains also carried genes characteristic of an integron, a novel genetic element which enables the formation of tandem arrays of antibiotic resistance genes. Hgr strains lacking antibiotic resistance showed no evidence of integron components.
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Affiliation(s)
- J Wireman
- Department of Microbiology, University of Georgia, Athens 30602-2605, USA
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Osborn AM, Bruce KD, Strike P, Ritchie DA. Distribution, diversity and evolution of the bacterial mercury resistance (mer) operon. FEMS Microbiol Rev 1997; 19:239-62. [PMID: 9167257 DOI: 10.1111/j.1574-6976.1997.tb00300.x] [Citation(s) in RCA: 174] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Mercury and its compounds are distributed widely across the earth. Many of the chemical forms of mercury are toxic to all living organisms. However, bacteria have evolved mechanisms of resistance to several of these different chemical forms, and play a major role in the global cycling of mercury in the natural environment. Five mechanisms of resistance to mercury compounds have been identified, of which resistance to inorganic mercury (HgR) is the best understood, both in terms of the mechanisms of resistance to mercury and of resistance to heavy metals in general. Resistance to inorganic mercury is encoded by the genes of the mer operon, and can be located on transposons, plasmids and the bacterial chromosome. Such systems have a worldwide geographical distribution, and furthermore, are found across a wide range of both Gram-negative and Gram-positive bacteria from both natural and clinical environments. The presence of mer genes in bacteria from sediment cores suggest that mer is an ancient system. Analysis of DNA sequences from mer operons and genes has revealed genetic variation both in operon structure and between individual genes from different mer operons, whilst analysis of bacteria which are sensitive to inorganic mercury has identified a number of vestigial non-functional operons. It is hypothesised that mer, due to its ubiquity with respect to geographical location, environment and species range, is an ancient system, and that ancient bacteria carried genes conferring resistance to mercury in response to increased levels of mercury in natural environments, perhaps resulting from volcanic activity. Models for the evolution of both a basic mer operon and for the Tn21-related family of mer operons and transposons are suggested. The study of evolution in bacteria has recently become dominated by the generation of phylogenies based on 16S rRNA genes. However, it is important not to underestimate the roles of horizontal gene transfer and recombinational events in evolution. In this respect mer is a suitable system for evaluating phylogenetic methods which incorporate the effects of horizontal gene transfer. In addition, the mer operon provides a model system in the study of environmental microbiology which is useful both as an example of a genotype which is responsive to environmental pressures and as a generic tool for the development of new methodology for the analysis of bacterial communities in natural environments.
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Affiliation(s)
- A M Osborn
- School of Biological Sciences, Donnan Laboratories, University of Liverpool, UK
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Boutibonnes P, Giard JC, Hartke A, Thammavongs B, Auffray Y. Characterization of the heat shock response in Enterococcus faecalis. Antonie Van Leeuwenhoek 1993; 64:47-55. [PMID: 8274003 DOI: 10.1007/bf00870921] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have characterized the general properties of the heat shock response of the Gram-positive hardy bacterium Enterococcus faecalis. The heat resistance (60 degrees C or 62.5 degrees C, 30 min) of log phase cells of E. faecalis grown at 37 degrees C was enhanced by exposing cells to a prior heat shock at 45 degrees C or 50 degrees C for 30 min. These conditioning temperatures also induced ethanol (22%, v/v) tolerance. The onset of thermotolerance was accompanied by the synthesis of a number of heat shock proteins. The most prominent bands had molecular weights in the range of 48 to 94kDa. By Western blot analysis two of them were found to be immunologically related to the well known DnaK (72kDa) and GroEL (63kDa) heat shock proteins of Escherichia coli. Four other proteins showing little or no variations after exposure to heat are related to DnaJ, GrpE and Lon (La) E. coli proteins and to the Bacillus subtilis sigma 43 factor. Ethanol (2% or 4%, v/v) treatments elicited a similar response although there was a weaker induction of heat shock proteins than with heat shock.
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Affiliation(s)
- P Boutibonnes
- Laboratory of Microbial Genetics, University of Caen, France
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