-
Clinical Microbiology Reviews Oct 2016Bacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual... (Review)
Review
Bacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual infection cycle. For enteric pathogens, the ability to adapt to numerous host factors under the harsh conditions of the gastrointestinal tract is critical for establishing infection. One such host factor readily encountered by enteric bacteria is bile, an innately antimicrobial detergent-like compound essential for digestion and nutrient absorption. Not only have enteric pathogens evolved to resist the bactericidal conditions of bile, but these bacteria also utilize bile as a signal to enhance virulence regulation for efficient infection. This review provides a comprehensive and up-to-date analysis of bile-related research with enteric pathogens. From common responses to the unique expression of specific virulence factors, each pathogen has overcome significant challenges to establish infection in the gastrointestinal tract. Utilization of bile as a signal to modulate virulence factor expression has led to important insights for our understanding of virulence mechanisms for many pathogens. Further research on enteric pathogens exposed to this in vivo signal will benefit therapeutic and vaccine development and ultimately enhance our success at combating such elite pathogens.
Topics: Animals; Bile; Disease Models, Animal; Enterobacteriaceae; Gene Expression Regulation, Bacterial; Host-Pathogen Interactions; Humans; Microbial Viability; Virulence; Virulence Factors
PubMed: 27464994
DOI: 10.1128/CMR.00031-16 -
Microbiology Spectrum Feb 2022Mobile genetic elements (MGEs) are often associated with antimicrobial resistance genes (ARGs). They are responsible for intracellular transposition between different...
Intracellular Transposition and Capture of Mobile Genetic Elements following Intercellular Conjugation of Multidrug Resistance Conjugative Plasmids from Clinical Isolates.
Mobile genetic elements (MGEs) are often associated with antimicrobial resistance genes (ARGs). They are responsible for intracellular transposition between different replicons and intercellular conjugation and are therefore important agents of ARG dissemination. Detection and characterization of functional MGEs, especially in clinical isolates, would increase our understanding of the underlying pathways of transposition and recombination and allow us to determine interventional strategies to interrupt this process. Entrapment vectors can be used to capture active MGEs, as they contain a positive selection genetic system conferring a selectable phenotype upon the insertion of an MGE within certain regions of that system. Previously, we developed the pBACpAK entrapment vector that results in a tetracycline-resistant phenotype when MGEs translocate and disrupt the repressor gene. We have previously used pBACpAK to capture MGEs in clinical Escherichia coli isolates following transformation with pBACpAK. In this study, we aimed to extend the utilization of pBACpAK to other bacterial taxa. We utilized an MGE-free recipient E. coli strain containing pBACpAK to capture MGEs on conjugative, ARG-containing plasmids following conjugation from clinical donors. Following the conjugative transfer of multiple conjugative plasmids and screening for tetracycline resistance in these transconjugants, we captured several insertion sequence (IS) elements and novel transposons (Tn and Tn) and detected the formation of novel putative composite transposons where the pBACpAK-located (A) is flanked by IS from the transferred conjugative plasmid, as well as the IS-mediated integration of an entire 119-kb, -containing conjugative plasmid from Klebsiella pneumoniae. By analyzing transposition activity within our MGE-free recipient, we can gain insights into the interaction and evolution of multidrug resistance-conferring MGEs following conjugation, including the movement of multiple ISs, the formation of composite transposons, and cointegration and/or recombination between different replicons in the same cell. This combination of recipient and entrapment vector will allow fine-scale experimental studies of factors affecting intracellular transposition and MGE formation in and from ARG-encoding MGEs from multiple species of clinically relevant .
Topics: Anti-Bacterial Agents; Conjugation, Genetic; DNA Transposable Elements; Drug Resistance, Multiple, Bacterial; Enterobacteriaceae; Enterobacteriaceae Infections; Escherichia coli; Gene Transfer, Horizontal; Humans; Klebsiella pneumoniae; Plasmids
PubMed: 35044219
DOI: 10.1128/spectrum.02140-21 -
Antimicrobial Resistance and Infection... May 2020Epidemiological studies suggested that determinants for antibiotic resistance have originated in aquaculture. Recently, the integrated agriculture-aquaculture system has...
BACKGROUND
Epidemiological studies suggested that determinants for antibiotic resistance have originated in aquaculture. Recently, the integrated agriculture-aquaculture system has been implemented, where fish are raised in ponds that receive agriculture drainage water. The present study aims to investigate the occurrence of β-lactamase and carbapenemase-producing Enterobacteriaceae in the integrated agriculture-aquaculture and the consequent public health implication.
METHODS
Samples were collected from fish, fishpond water inlets, tap water, outlet water, and workers at sites of integrated agriculture-aquacultures. Samples were also taken from inhabitants of the aquaculture surrounding areas. All samples were cultured on MacConkey agar, the Enterobacteriaceae isolates were tested for susceptibility to cephalosporins and carbapenems, and screened for bla, bla, bla, bla, bla, bla, bla, and bla. Strains having similar resistance phenotype and genotype were examined for the presence of Incompatible (Inc) plasmids.
RESULTS
A major proportion of the Enterobacteriaceae isolates were resistant to cephalosporins and carbapenems. Among the 66 isolates from fish, 34 were resistant to both cephalosporin and carbapenem groups, 26 to carbapenems alone, and 4 to cephalosporins alone. Of the 15 isolates from fishpond water inlets, 8 showed resistance to both groups, 1 to carbapenems alone, and 5 to cephalosporins alone. Out of the 33 isolates from tap water, 17 were resistant to both groups, and 16 to cephalosporins alone. Similarly, of the 16 outlet water isolates, 10 were resistant to both groups, and 6 to cephalosporins alone. Furthermore, of the 30 examined workers, 15 carried Enterobacteriaceae resistant strains, 10 to both groups, and 5 to cephalosporins alone. Similar strains were isolated from the inhabitants of the aquaculture surrounding areas. Irrespective of source of samples, strains resistant to all examined antibiotics, carried predominantly the carbapenemase gene bla either alone or with the β-lactamase genes (bla, bla, bla, and bla). The isolates from fish, water, and workers harboured a wide-range of multi-drug-resistance Inc. plasmids, which were similar among all isolates.
CONCLUSION
The present findings suggest transmission of the resistance genes among Enterobacteriaceae strains from different sources. This reiterates the need for control strategies that focus on humans, animals, water, and sewage systems to solve the antibiotic resistance problem.
Topics: Animals; Bacterial Proteins; Carbapenem-Resistant Enterobacteriaceae; Egypt; Enterobacteriaceae; Fisheries; Hand; Humans; Plasmids; Tilapia; beta-Lactamases
PubMed: 32430083
DOI: 10.1186/s13756-020-00736-3 -
FEMS Immunology and Medical Microbiology Mar 2008CTX-M- and AmpC-type beta-lactamases comprise the two most rapidly growing populations among the extended-spectrum cephalosporinases. The evolution and dissemination of... (Review)
Review
CTX-M- and AmpC-type beta-lactamases comprise the two most rapidly growing populations among the extended-spectrum cephalosporinases. The evolution and dissemination of resistance genes encoding these enzymes occur mostly through the transmission of plasmids. The high prevalence of clinical isolates of Enterobacteriaceae producing the plasmid-mediated extended-spectrum cephalosporinases resembles an epidemic of plasmids, and has generated serious therapeutic problems. This review describes the emergence and worldwide spread of various classes of plasmid-mediated extended-spectrum cephalosporinases in Salmonella and other Enterobacteriaceae, the transfer mechanism of the plasmids, detection methods, and therapeutic choices.
Topics: Bacterial Proteins; Cephalosporinase; Enterobacteriaceae; Plasmids; beta-Lactam Resistance
PubMed: 18093140
DOI: 10.1111/j.1574-695X.2007.00360.x -
Journal of Clinical Microbiology Jan 1985In 1972 there were only 11 genera and 26 species in the family Enterobacteriaceae. Today there are 22 genera, 69 species, and 29 biogroups or Enteric Groups. This paper... (Review)
Review
In 1972 there were only 11 genera and 26 species in the family Enterobacteriaceae. Today there are 22 genera, 69 species, and 29 biogroups or Enteric Groups. This paper is a review of all of the new organisms. It has a series of differential charts to assist in identification and a large chart with the reactions of 98 different organisms for 47 tests often used in identification. A simplified version of this chart gives the most common species and tests most often used for identification. The sources of the new organisms are listed, and their role in human disease is discussed. Fourteen new groups of Enterobacteriaceae are described for the first time. These new groups are biochemically distinct from previously described species, biogroups, and Enteric Groups of Enterobacteriaceae. The new groups are Citrobacter amalonaticus biogroup 1, Klebsiella group 47 (indole positive, ornithine positive), Serratia marcescens biogroup 1, and unclassified Enteric Groups 17, 45, 57, 58, 59, 60, 63, 64, 68, and 69.
Topics: Adult; Aged; Citrobacter; DNA, Bacterial; Enterobacter; Enterobacteriaceae; Enterobacteriaceae Infections; Escherichia; Fermentation; Humans; Infant, Newborn; Klebsiella; Middle Aged; Nucleic Acid Hybridization; Proteus; Salmonella; Serratia; Terminology as Topic; Yersinia
PubMed: 3881471
DOI: 10.1128/jcm.21.1.46-76.1985 -
Biomedical and Environmental Sciences :... Sep 2023is a Gram-negative bacterium belonging to the Enterobacteriaceae family. To our knowledge, this is the first report of a carbapenem-resistant strain isolated from a...
is a Gram-negative bacterium belonging to the Enterobacteriaceae family. To our knowledge, this is the first report of a carbapenem-resistant strain isolated from a healthy newborn. The strain isolated in this study carried four plasmids that may serve as reservoirs for antibiotic resistance genes. Plasmids 2 and 4 did not harbor any antimicrobial resistance genes. Plasmid 3 is a novel plasmid containing three resistance genes. The gene harbored in the strain was most similar to at the nucleotide level, with a similarity of 99.4% (737/741). This case highlights the importance of considering as a potential cause of infections in children.
Topics: Infant, Newborn; Child; Humans; Female; Enterobacteriaceae Infections; Enterobacteriaceae; Anti-Bacterial Agents; Plasmids
PubMed: 37803900
DOI: 10.3967/bes2023.104 -
Journal of Infection in Developing... Sep 2020The clinical role of Leclercia adecarboxylata as an opportunistic pathogen in the context of human infections have been highlighted by multiple published case reports,...
INTRODUCTION
The clinical role of Leclercia adecarboxylata as an opportunistic pathogen in the context of human infections have been highlighted by multiple published case reports, describing these bacteria as novel or emerging pathogens.
METHODOLOGY
The study included L. adecarboxylata isolates and laboratory data collected, corresponding to a 13-year time period (between 1 January 2005 and 31 December 2017). Presumptively identified L. adecarboxylata isolates were re-identified using VITEK 2 Compact ID/AST and MALDI-TOF MS analysis.
RESULTS
n = 34 isolates were verified by VITEK 2 system and MALDI-TOF. The fosfomycin-agar and CPS Elite agar were effective in the phenotypic differentiation of the isolates. N = 18 (52.9%) of L. adecarboxylata was considered as clinically significant pathogens (based on the clinical signs and symptoms), while n = 16 (47.1%) were considered as contaminants. These pathogens were isolated from wound/abscess samples (n = 9), urine samples (n = 6) and blood cultures (n = 3). 31 out of 34 isolates (91.2%) were pan-sensitive (i.e. wild type) to the tested antibiotics. The median age of affected patients was 57 years (range: 12-80 years), 11 out of 18 patients (61.1%) presented with underlying immunosuppression at the time of isolation.
CONCLUSIONS
Based on the finding of this study, the actual (published) frequency of L. adecarboxylata infections needs to be re-evaluated as the risk of misidentification (and reporting the isolate as a pan-sensitive Escherichia coli) is high. Additional reporting of cases, both from a microbiological and clinical standpoint, could help clinicians develop a better understanding of the potential of this organism as a pathogen.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Child; Enterobacteriaceae; Enterobacteriaceae Infections; Female; Humans; Hungary; Immunocompromised Host; Male; Mass Spectrometry; Microbial Sensitivity Tests; Middle Aged; Molecular Diagnostic Techniques; Reagent Kits, Diagnostic; Retrospective Studies; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Young Adult
PubMed: 33031089
DOI: 10.3855/jidc.12598 -
BMJ Case Reports Mar 2022A 34-year-old man on active chemotherapy was hospitalised with fever, chills and rigours after power-washing a pig pen on a farm. His blood cultures grew , a...
A 34-year-old man on active chemotherapy was hospitalised with fever, chills and rigours after power-washing a pig pen on a farm. His blood cultures grew , a gram-negative rod in the family, which has been isolated from a variety of environments including soil, surface water, as well as in the gastrointestinal flora of farm animals. The likely source of infection was his tunnelled central venous catheter exposed to water contaminated by faeces when he was washing the pig pen. While there have been several cases reported of catheter-related bacteraemia, to our knowledge there are very few reports of infection spread in this manner.
Topics: Animals; Bacteremia; Catheters; Enterobacteriaceae; Enterobacteriaceae Infections; Humans; Immunocompromised Host; Male; Swine
PubMed: 35332006
DOI: 10.1136/bcr-2021-247496 -
Japanese Journal of Infectious Diseases Nov 2016Among 144 carbapenem-resistant Enterobacteriaceae strains isolated from 4 hospitals in Yunnan province, 113 were identified as carbapenemase-producing Enterobacteriaceae...
Among 144 carbapenem-resistant Enterobacteriaceae strains isolated from 4 hospitals in Yunnan province, 113 were identified as carbapenemase-producing Enterobacteriaceae (CPE). Bla (99/113, 87.6%) was the most common carbapenemase gene and Klebsiella pneumoniae (100/113, 88.5%) was the most common species. Bla (11/113, 9.7%), bla (10/113, 8.8%), and bla (1/113, 0.9%) genes were also detected. Extended-spectrum β-lactamase genes were common in CPE, and the SHV- and CTX-M-types were predominant.
Topics: Bacterial Proteins; China; Enterobacteriaceae; Enterobacteriaceae Infections; Hospitals; Humans; Prevalence; beta-Lactamases
PubMed: 26902217
DOI: 10.7883/yoken.JJID.2015.471 -
BMJ Case Reports Sep 2020A 72-year-old woman presented with concern for a necrotising soft tissue infection (NSTI) 6 days after a tree branch impaled her left lower extremity while hiking in...
A 72-year-old woman presented with concern for a necrotising soft tissue infection (NSTI) 6 days after a tree branch impaled her left lower extremity while hiking in Hawaii. The wound was irrigated and closed at a local clinic in Hawaii. She completed a 5-day course of clindamycin. She presented to our emergency department 1 day after completion of antibiotics due to worsening erythema and malodorous drainage. Local wound exploration revealed bullae and easy dissection of fascial planes. CT scan revealed complex heterogeneous fluid and inflammatory stranding in the posterior calf. Clinical and radiographic findings raised concern for NSTI prompting initiation of broad spectrum antibiotics and urgent operative debridement. Wound cultures and deep tissues cultures returned positive for pansusceptible She underwent two additional operative debridements and transitioned to negative pressure wound therapy during her hospitalisation. She was discharged home on oral amoxicillin/clavulanate on hospital day 6.
Topics: Aged; Anti-Bacterial Agents; Clindamycin; Debridement; Drainage; Enterobacteriaceae; Enterobacteriaceae Infections; Fasciitis, Necrotizing; Female; Humans; Negative-Pressure Wound Therapy; Soft Tissue Infections
PubMed: 32994267
DOI: 10.1136/bcr-2020-235633