-
Frontiers in Microbiology 2017South American Camelids have an increasing relevance in local economies, worldwide. These animals are bred for their meat, fur and as companion and therapy animals....
South American Camelids have an increasing relevance in local economies, worldwide. These animals are bred for their meat, fur and as companion and therapy animals. Thus, their sanitary status should be well-established. According to the OIE (World Organization for Animal Health), respiratory infections mainly produced by spp. have been reported for camelids. It has been stated that this microorganism causes a mild disease, although many authors report it is an important cause of mortality among alpacas. Nevertheless, the incidence of infection by spp. in camelids still needs to be investigated. The aim of the present study was to analyze the occurrence of nasopharyngeal colonization of by respiratory bacteria, and to assess the usefulness of serological tests for clinical diagnosis. The colonization was studied by culture techniques carried out with material taken by nasopharyngeal swabs. Bacterial isolates were first phenotypically characterized and then identified by MALDI/TOF-MS. The presence of specific serum antibodies was studied by ELISA and Western blot. In the present work spp. was not found. Nevertheless, we report for the first time, the colonization of by bacteria of the , at a reliable level in 19.4% of the animals. species are found in different environmental sources, as well as vegetables, animals, and humans, and their role in infections has recently gained relevance. The results presented herein contribute to a better understanding of the respiratory microbiota in camelids, and increase the knowledge about environmental distribution of non- species. Given that these respiratory bacteria might be the cause of infection among cattle, and even humans, this report highlights the need for further research.
PubMed: 28303121
DOI: 10.3389/fmicb.2017.00278 -
Antimicrobial Agents and Chemotherapy Apr 2020Tigecycline serves as one of the antibiotics of last resort to treat multidrug-resistant (including carbapenem-resistant) pathogens. However, the recently emerged...
Tigecycline serves as one of the antibiotics of last resort to treat multidrug-resistant (including carbapenem-resistant) pathogens. However, the recently emerged plasmid-mediated tigecycline resistance mechanism, Tet(X), challenges the clinical efficacy of this class of antibiotics. In this study, we detected 180 (X)-harboring isolates (8.9%, = 180) from 2,018 samples collected from avian farms and adjacent environments in China. Eighteen (X)-harboring isolates (10.0%) were found to cocarry the carbapenemase gene , mostly from waterfowl samples (94.4%, 17/18). Interestingly, among six strains, (X) and were found to colocalize on the same plasmids. Moreover, whole-genome sequencing (WGS) revealed a novel orthologue of (X) in the six isolates coharboring (X) and Inverse PCR suggested that the two (X) genes form a single transposable unit and may be cotransferred. Sequence comparison between six (X)- and -coharboring plasmids showed that they shared a highly homologous plasmid backbone even though they were isolated from different species (three from , two from , and one from ) from various sources and from different geological regions, suggesting the horizontal genetic transfer of a common (X)- and -coharboring plasmid among species in China. Emergence and spread of such plasmids and strains are of great clinical concern, and measures must be implemented to avoid their dissemination.
Topics: Acinetobacter; Acinetobacter Infections; Animals; Anti-Bacterial Agents; Bird Diseases; Birds; Carbapenems; China; Drug Resistance, Bacterial; Gene Transfer, Horizontal; Microbial Sensitivity Tests; Molecular Epidemiology; Plasmids; Tetracycline Resistance; Tigecycline; Whole Genome Sequencing
PubMed: 32122894
DOI: 10.1128/AAC.02502-19 -
IDCases 2015Bacteremia is currently one of the infections with the highest mortality in hospitals [1]. Acinetobacter lwoffii and Acinetobacter baumannii are gram-negative bacteria...
Bacteremia is currently one of the infections with the highest mortality in hospitals [1]. Acinetobacter lwoffii and Acinetobacter baumannii are gram-negative bacteria and both represent opportunistic pathogens. In certain cases, the management can be challenging since these organisms can be highly resistant to antimicrobial agents. Clinical illnesses associated with Acinetobacter include pneumonia, meningitis, peritonitis, endocarditis and infections of the urinary tract and skin [1]. Acinetobacter bacteremia represents a serious and ever increasing problem because of the high associated morbidity and mortality.
PubMed: 26793461
DOI: 10.1016/j.idcr.2015.05.002 -
MSphere May 2024The two species that account for most cases of -associated bacteremia in the United Kingdom are , often a commensal but also an emerging pathogen, and , a well-known...
UNLABELLED
The two species that account for most cases of -associated bacteremia in the United Kingdom are , often a commensal but also an emerging pathogen, and , a well-known antibiotic-resistant species. While these species both cause similar types of human infection and occupy the same niche, (unlike ) has thus far remained susceptible to antibiotics. Comparatively little is known about the biology of , and this is the largest study on it conducted to date, providing valuable insights into its behaviour and potential threat to human health. This study aimed to explain the antibiotic susceptibility, virulence, and fundamental biological differences between these two species. The relative susceptibility of was explained as it encoded fewer antibiotic resistance and efflux pump genes than (9 and 30, respectively). While both species had markers of horizontal gene transfer, encoded more DNA defense systems and harbored a far more restricted range of plasmids. Furthermore, displayed a reduced ability to select for antibiotic resistance mutations, form biofilm, and infect both and in models of infection. This study suggests that the emerging pathogen has remained susceptible to antibiotics because mechanisms exist to make it highly selective about the DNA it acquires, and we hypothesize that the fact that it only harbors a single RND system restricts the ability to select for resistance mutations. This provides valuable insights into how development of resistance can be constrained in Gram-negative bacteria.
IMPORTANCE
is often a harmless commensal but is also an emerging pathogen and is the most common cause of -derived bloodstream infections in England and Wales. In contrast to the well-studied and often highly drug-resistant , has remained susceptible to antibiotics. This study explains why this organism has not evolved resistance to antibiotics. These new insights are important to understand why and how some species develop antibiotic resistance, while others do not, and could inform future novel treatment strategies.
Topics: Acinetobacter; Virulence; Acinetobacter Infections; Anti-Bacterial Agents; Biofilms; Microbial Sensitivity Tests; Animals; Humans; Drug Resistance, Bacterial; Acinetobacter baumannii; Mice; Gene Transfer, Horizontal; United Kingdom; Female; Plasmids
PubMed: 38578105
DOI: 10.1128/msphere.00109-24 -
Frontiers in Microbiology 2021Oil tea ( spp.) is endemic to the hilly regions in the subtropics. is resistant to diseases such as anthracnose and root rot, while is a high-yield species but...
Oil tea ( spp.) is endemic to the hilly regions in the subtropics. is resistant to diseases such as anthracnose and root rot, while is a high-yield species but susceptible to these diseases. We hypothesize that differences in the rhizosphere microbial communities and functions will elucidate the resistance mechanisms of these species. We used high-throughput sequencing over four seasons to characterize the rhizosphere microbiome of (Rhizo-Sus) and (Rhizo-Res) and of the bulk soil control (BulkS). In Rhizo-Res, bacterial richness and diversity (Shannon index) in autumn and winter were both higher than that in Rhizo-Sus. In Rhizo-Res, fungal richness in autumn and winter and diversity in summer, autumn, and winter were higher than that in Rhizo-Sus. The seasonal variations in bacterial community structure were different, while that of fungal community structure were similar between Rhizo-Res and Rhizo-Sus. Gram-positive, facultatively anaerobic, and stress-tolerant bacteria were the dominant groups in Rhizo-Sus, while Gram-negative bacteria were the dominant group in Rhizo-Res. The significant differences in bacterial and fungal functions between Rhizo-Sus and Rhizo-Res were as follows: (1) in Rhizo-Sus, there were three bacterial and four fungal groups with plant growth promoting potentials, such as and , and one bacterium and three fungi with pathogenic potentials, such as sp. and ; (2) in Rhizo-Res, there were also three bacteria and four fungal groups with plant-growth-promoting potentials (e.g., and ) but only one phytopathogen (). In summary, the rhizosphere microbiome of disease-resistant is characterized by a higher richness and diversity of microbial communities, more symbiotic fungal communities, and fewer pathogens compared to the rhizosphere of high-yield but disease-susceptible
PubMed: 34733251
DOI: 10.3389/fmicb.2021.732905 -
Frontiers in Microbiology 2020Antimicrobial resistance is an ancient bacterial defense mechanism that has rapidly spread due to the frequent use of antibiotics for disease treatment and livestock...
Antimicrobial resistance is an ancient bacterial defense mechanism that has rapidly spread due to the frequent use of antibiotics for disease treatment and livestock growth promotion. We are becoming increasingly aware that pathogens, such as members of the genus , are precipitously evolving drug resistances through multiple mechanisms, including the acquisition of antibiotic resistance genes. In this study, we isolated three multidrug resistant species from birds on a free-range farm. , , and were isolated from hens, turkeys and ducks and were resistant to 14 clinically relevant antibiotics, including several listed by the World Health Organization as essential medicines. Co-culturing any of the three species with resulted in contact-dependent release of intact resistance determinants. We also isolated several lytic bacteriophages and selected two of these phages to be included in this study based on differences in plaquing characteristics, nucleic acid content and viral morphology. Both phages released host DNA, including antibiotic resistance genes during cell lysis and we demonstrated that these resistance determinants were transferable to a naïve strain of . This study demonstrates that contact-dependent competition between bacterial species can readily contribute to DNA release into the environment, including antibiotic resistance determinants. We also highlight that the constant lysis and turnover of bacterial populations during the natural lifecycle of a lytic bacteriophage is an underappreciated mechanism for the liberation of DNA and subsequent genetic exchange.
PubMed: 32922376
DOI: 10.3389/fmicb.2020.01918 -
Brazilian Journal of Biology = Revista... 2023Pyrethroid pesticides are commonly used for pest control in agriculture setup, veterinary and home garden. They are now posing increased risks to non-targeted organisms...
Pyrethroid pesticides are commonly used for pest control in agriculture setup, veterinary and home garden. They are now posing increased risks to non-targeted organisms associated to human beings due to their considerable use. The present work deals with the isolation of bacteria with tolerance to high concentrations of bifenthrin and cypermethrin from contaminated soil. Enrichment culture technique (bifenthrin concentration = 50-800 mg/L) was used for bacterial isolation. Bacteria that showed growth on minimal media with bifenthrin were also sub-cultured on minimal media with cypermethrin. Bacteria showing luxurious growth on both the pyrethroid, were screened out based on their morphological, biochemical parameters and by API 20NE Kit. Phylogenetic studies revealed that, one bacterial isolate (MG04) belonging to Acinetobacter lwoffii and other five bacterial isolates (MG06, MG05, MG01, MG03 and MG02) cluster with Pseudomonas aeruginosa, Pseudomonas putida respectively. Isolated members of genera Pseudomonas and Acinetobacter could be used for further detailed degradation studies by using FTIR, HPLC-MS or GC-MS analysis.
Topics: Humans; Soil; Phylogeny; Pyrethrins; Agriculture; Bacteria; Soil Microbiology; Biodegradation, Environmental; Soil Pollutants
PubMed: 37132742
DOI: 10.1590/1519-6984.271790 -
Journal of Global Antimicrobial... Dec 2020The aim of this study was to identify Acinetobacter spp. strains from paediatric patients, to determine their genetic relationship, to detect antibiotic resistance genes...
OBJECTIVES
The aim of this study was to identify Acinetobacter spp. strains from paediatric patients, to determine their genetic relationship, to detect antibiotic resistance genes and to evaluate the role of efflux pumps in antibiotic resistance.
METHODS
A total of 54 non-duplicate, non-consecutive Acinetobacter spp. isolates were collected from paediatric patients. Their genetic relationship, antibiotic resistance profile, efflux pump activity, antibiotic resistance genes and plasmid profile were determined.
RESULTS
The isolates were identified as 24 Acinetobacter haemolyticus, 24 Acinetobacter calcoaceticus-baumannii (Acb) complex and 1 strain each of Acinetobacter junii, Acinetobacter radioresistens, Acinetobacter indicus, Acinetobacter lwoffii, Acinetobacter ursingii and Acinetobacter venetianus. The 24 A. haemolyticus were considered genetically unrelated. One strain was resistant to carbapenems, two to cephalosporins, two to ciprofloxacin and sixteen to aminoglycosides. The antibiotic resistance genes bla (29%), bla (4%), bla (8%), bla (29%), bla (4%), aac(6')-Ig (38%) and the novel variants bla (13%), bla (75%), aac(6')-Iga (4%), aac(6')-Igb (13%) and aac(6')-Igc (42%) were detected. Among 24 Acb complex, 5 were multidrug-resistant, carbapenem-resistant strains carrying bla and bla; they were genetically related and had the same plasmid profile. Other species were susceptible. In some strains of A. haemolyticus and Acb complex, the role of RND efflux pumps was evidenced by a decrease in the MICs for cefotaxime, amikacin and ciprofloxacin in the presence of an efflux pump inhibitor.
CONCLUSIONS
This study identified isolates of A. haemolyticus carrying new β-lactamase variants and shows for the first time the contribution of efflux pumps to antibiotic resistance in this species.
Topics: Acinetobacter; Acinetobacter Infections; Acinetobacter baumannii; Child; Hospitals, Pediatric; Humans; Mexico
PubMed: 32916332
DOI: 10.1016/j.jgar.2020.08.014 -
Pharmaceuticals (Basel, Switzerland) Jul 2020Curcumin, a principal bioactive substance of turmeric ( L.), is reported as a strong antioxidant, anti-inflammatory, antibacterial, antifungal, and antiviral agent....
Curcumin, a principal bioactive substance of turmeric ( L.), is reported as a strong antioxidant, anti-inflammatory, antibacterial, antifungal, and antiviral agent. However, its antimicrobial properties require further detailed investigations into clinical and multidrug-resistant (MDR) isolates. In this work, we tested curcumin's efficacy against over 100 strains of pathogens belonging to 19 species. This activity was determined by the broth microdilution method and by calculating the minimum inhibitory concentration (MIC). Our findings confirmed a much greater sensitivity of Gram-positive than Gram-negative bacteria. This study exhibited a significantly larger variation in the curcumin activity than previous works and suggested that numerous clinical strains of widespread pathogens have a poor sensitivity to curcumin. Similarly, the MICs of the MDR types of , , , and were high (≥2000 µg/mL). However, curcumin was effective against some species and strains: (median MIC = 31.25 µg/mL), methicillin-sensitive (250 µg/mL), (250 µg/mL), and individual strains of and (62.5 µg/mL). The sensitivity of species was not associated with its affiliation to the genus, and it could differ a lot (e.g., , and , ). Hence, curcumin can be considered as a promising antibacterial agent, but with a very selective activity.
PubMed: 32708619
DOI: 10.3390/ph13070153 -
MSystems 2018Microbiome analyses of low-biomass samples are challenging because of contamination and inefficiencies, leading many investigators to employ low-throughput methods with...
Microbiome analyses of low-biomass samples are challenging because of contamination and inefficiencies, leading many investigators to employ low-throughput methods with minimal controls. We developed a new automated protocol, KatharoSeq (from the Greek katharos [clean]), that outperforms single-tube extractions while processing at least five times as fast. KatharoSeq incorporates positive and negative controls to reveal the whole bacterial community from inputs of as few as 50 cells and correctly identifies 90.6% (standard error, 0.013%) of the reads from 500 cells. To demonstrate the broad utility of KatharoSeq, we performed 16S rRNA amplicon and shotgun metagenome analyses of the Jet Propulsion Laboratory spacecraft assembly facility (SAF; = 192, 96), 52 rooms of a neonatal intensive care unit (NICU; = 388, 337), and an endangered-abalone-rearing facility ( = 192, 123), obtaining spatially resolved, unique microbiomes reproducible across hundreds of samples. The SAF, our primary focus, contains 32 sOTUs (sub-OTUs, defined as exact sequence matches) and their inferred variants identified by the deblur algorithm, with four (, , sp., and ) being present in >75% of the samples. According to microbial spatial topography, the most abundant cleanroom contaminant, , is related to human foot traffic exposure. In the NICU, we have been able to discriminate environmental exposure related to patient infectious disease, and in the abalone facility, we show that microbial communities reflect the marine environment rather than human input. Consequently, we demonstrate the feasibility and utility of large-scale, low-biomass metagenomic analyses using the KatharoSeq protocol. Various indoor, outdoor, and host-associated environments contain small quantities of microbial biomass and represent a niche that is often understudied because of technical constraints. Many studies that attempt to evaluate these low-biomass microbiome samples are riddled with erroneous results that are typically false positive signals obtained during the sampling process. We have investigated various low-biomass kits and methods to determine the limit of detection of these pipelines. Here we present KatharoSeq, a high-throughput protocol combining laboratory and bioinformatic methods that can differentiate a true positive signal in samples with as few as 50 to 500 cells. We demonstrate the application of this method in three unique low-biomass environments, including a SAF, a hospital NICU, and an abalone-rearing facility.
PubMed: 29577086
DOI: 10.1128/mSystems.00218-17