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International Microbiology : the... Feb 2024Polymyxin B is considered a last-line therapeutic option against multidrug-resistant gram-negative bacteria, especially in COVID-19 coinfections or other serious...
BACKGROUND
Polymyxin B is considered a last-line therapeutic option against multidrug-resistant gram-negative bacteria, especially in COVID-19 coinfections or other serious infections. However, the risk of antimicrobial resistance and its spread to the environment should be brought to the forefront.
METHODS
Pandoraea pnomenusa M202 was isolated under selection with 8 mg/L polymyxin B from hospital sewage and then was sequenced by the PacBio RS II and Illumina HiSeq 4000 platforms. Mating experiments were performed to evaluate the transfer of the major facilitator superfamily (MFS) transporter in genomic islands (GIs) to Escherichia coli 25DN. The recombinant E. coli strain Mrc-3 harboring MFS transporter encoding gene FKQ53_RS21695 was also constructed. The influence of efflux pump inhibitors (EPIs) on MICs was determined. The mechanism of polymyxin B excretion mediated by FKQ53_RS21695 was investigated by Discovery Studio 2.0 based on homology modeling.
RESULTS
The MIC of polymyxin B for the multidrug-resistant bacterial strain P. pnomenusa M202, isolated from hospital sewage, was 96 mg/L. GI-M202a, harboring an MFS transporter-encoding gene and conjugative transfer protein-encoding genes of the type IV secretion system, was identified in P. pnomenusa M202. The mating experiment between M202 and E. coli 25DN reflected the transferability of polymyxin B resistance via GI-M202a. EPI and heterogeneous expression assays also suggested that the MFS transporter gene FKQ53_RS21695 in GI-M202a was responsible for polymyxin B resistance. Molecular docking revealed that the polymyxin B fatty acyl group inserts into the hydrophobic region of the transmembrane core with Pi-alkyl and unfavorable bump interactions, and then polymyxin B rotates around Tyr43 to externally display the peptide group during the efflux process, accompanied by an inward-to-outward conformational change in the MFS transporter. Additionally, verapamil and CCCP exhibited significant inhibition via competition for binding sites.
CONCLUSIONS
These findings demonstrated that GI-M202a along with the MFS transporter FKQ53_RS21695 in P. pnomenusa M202 could mediate the transmission of polymyxin B resistance.
Topics: Polymyxin B; Escherichia coli; Genomic Islands; Molecular Docking Simulation; Sewage; Membrane Transport Proteins; Anti-Bacterial Agents; Microbial Sensitivity Tests; Burkholderiaceae
PubMed: 37316617
DOI: 10.1007/s10123-023-00384-8 -
Journal of Applied Microbiology Apr 2023Pandoraea pnomenusa MCB032 completely degrades chlorobenzene, whose metabolic pathway is encoded by cbs and clc gene clusters. The putative regulatory factors ClcR and...
AIMS
Pandoraea pnomenusa MCB032 completely degrades chlorobenzene, whose metabolic pathway is encoded by cbs and clc gene clusters. The putative regulatory factors ClcR and CbsR are predicted to regulate the cbs and clc gene clusters. This research aims to understand the function of ClcR and CbsR.
METHODS AND RESULTS
RT-PCR analyses demonstrated that the cbsFAaAbAcAdB operon that encodes catabolic pathways for the degradation of chlorobenzene to chlorocatechol is located on an operon. Moreover, the clcABCDE operon is involved in the 3-chlorocatechol pathway. Gene knockout and transcriptional analysis showed that the transcription of the cbsFAaAbAcAdB operon is positively regulated by CbsR, whereas the clcABCDE operon is activated by ClcR. Primer extension analysis was used to locate the transcription start sites of the cbsFAaAbAcAdB and cbsR operons. Electrophoretic mobility shift assay analyses showed that CbsR is bound to the sites in the promoter regions of cbsFAaAbAcAdB and cbsR operons.
CONCLUSION
The XylR/NtrC-type regulator CbsR positively regulates the transcription of the cbsFAaAbAcAdB operon encoding the upstream pathway of chlorobenzene catabolism, while the LysR-type regulator ClcR activates the clcABCDE operon encoding the downstream pathway.
Topics: Transcription Factors; Promoter Regions, Genetic; Base Sequence; Chlorobenzenes; Operon; Gene Expression Regulation, Bacterial; Bacterial Proteins
PubMed: 36965871
DOI: 10.1093/jambio/lxad064 -
Acta Medica Portuguesa Feb 2023Pandoraea species are a newly described genus of multidrug-resistant, non-fermentative Gram-negative bacilli, mainly isolated from sputum samples of cystic fibrosis...
Pandoraea species are a newly described genus of multidrug-resistant, non-fermentative Gram-negative bacilli, mainly isolated from sputum samples of cystic fibrosis patients. In immunocompromised patients or with high antibiotic selective pressure, these pathogens are generally opportunistic and invasive. Although Pandoraea spp. are rare, the true incidence of these infections may be underestimated due to difficulties in microbial identification by phenotypic methods. We present the case of a 51-year-old woman, with new-onset fever after a prolonged hospitalization and multiple courses of antibiotics. Mass spectrometry assays identified Pandoraea pnomenusa in the blood cultures taken from the central venous catheter and in the catheter tip. Fever cessation after catheter removal suggests a catheter-related bloodstream infection. To the best of our knowledge, this is the first isolation of a Pandoraea spp. in Portugal, which should raise awareness to the emergence of these opportunistic and multidrug-resistant microorganisms, and the importance of its prompt identification.
Topics: Female; Humans; Middle Aged; Central Venous Catheters; Burkholderiaceae; Anti-Bacterial Agents; Cystic Fibrosis; Catheter-Related Infections
PubMed: 35604812
DOI: 10.20344/amp.16176 -
Infectious Disease Reports Mar 2022is a Gram-negative bacterium of the genus and is mainly associated with the colonization of structurally abnormal airways. During the COVID-19 pandemic, many...
is a Gram-negative bacterium of the genus and is mainly associated with the colonization of structurally abnormal airways. During the COVID-19 pandemic, many microorganisms have been associated with coinfection and superinfection in SARS-CoV-2 pneumonia, but so far, no coinfection or superinfection by has been reported. We present the first case describing this association in a previously healthy patient. Clinical manifestations, treatment, and outcomes are shown.
PubMed: 35314655
DOI: 10.3390/idr14020025 -
Journal of Cardiology Cases Jul 2021Late prosthetic valve endocarditis (PVE) is a life-threatening condition, commonly caused by bacterial organisms such as staphylococci, streptococci, or enterococci....
Late prosthetic valve endocarditis (PVE) is a life-threatening condition, commonly caused by bacterial organisms such as staphylococci, streptococci, or enterococci. Infrequently, it can be caused by rare organisms. We hereby report a case of late PVE of the aortic valve, due to a rare gram-negative bacterium It is the first reported case of PVE caused by this particular organism. The patient had infective endocarditis-induced prosthetic valve dehiscence, severe aortic regurgitation, and shock, which was managed with appropriate antibiotics and supportive medical treatment. < Late prosthetic valve infective endocarditis should always be an important differential diagnosis in patients with artificial valve presenting with congestive cardiac failure. This case report is about aortic valve dehiscence and acute aortic regurgitation because of prosthetic valve infective endocarditis due to a rare bacterium .
PubMed: 34257757
DOI: 10.1016/j.jccase.2020.12.003 -
Journal of Hazardous Materials Sep 2021Azoles are an emerging class of contaminants with a growing ubiquitous presence in the environment. This study investigates the aerobic microbial degradation of four...
Azoles are an emerging class of contaminants with a growing ubiquitous presence in the environment. This study investigates the aerobic microbial degradation of four azoles, pyrazole (PA), 1,2,4-triazole (TA), benzotriazole (BTA) and 5-methylbenzotriazole (5-MBTA), with return activated sludge and microbial enrichment cultures. Slow degradation of PA was observed in the presence of glucose and NH with a peak degradation rate of 0.5 mg d gVSS. TA was found to be highly persistent, with no significant degradation observed in 6-8 months under any incubation condition. In contrast, the benzotriazoles were readily degraded at faster rates in all incubation conditions. The degradation rates observed for BTA and 5-MBTA, when provided as the sole substrates, were 8.1 and 16.5 mg d gVSS, respectively. Two enrichment cultures, one degrading BTA and the other degrading 5-MBTA, were developed from the activated sludge. Mass balance studies revealed complete mineralization of 5-MBTA and partial breakdown of BTA by the enrichment cultures. Nocardioides sp. and Pandoraea pnomenusa were the most abundant bacteria in the BTA and 5-MBTA degrading enrichment cultures, respectively. The research shows large differences in the biodegradability of various azoles, ranging from complete mineralization of 5-MBTA to complete persistence for TA.
Topics: Azoles; Biodegradation, Environmental; Burkholderiaceae; Sewage
PubMed: 34229401
DOI: 10.1016/j.jhazmat.2021.126151 -
Infection and Drug Resistance 2021Bacteremia by spp. has rarely been described before. We report the first case of a possible prosthetic valve endocarditis, according to the modified Duke criteria, in...
Bacteremia by spp. has rarely been described before. We report the first case of a possible prosthetic valve endocarditis, according to the modified Duke criteria, in a 37-year old male injecting drug user suffering from recurrent endocarditis. Furthermore, we demonstrate biofilm formation by the isolates of this patient and investigate antibiotic resistance.
PubMed: 33854344
DOI: 10.2147/IDR.S301138 -
Transplantation Dec 2021Uncontrolled donation after circulatory death (DCD) donors are an extraordinary resource to increase the number of lungs available for transplantation. However, the risk...
BACKGROUND
Uncontrolled donation after circulatory death (DCD) donors are an extraordinary resource to increase the number of lungs available for transplantation. However, the risk of the warm ischemia resulting from cardiac arrest to irreversibly damage the organs is considerable. Moreover, graft preservation issues and organizational problems often worsen the dangerous effects of warm ischemia. Ex vivo lung perfusion (EVLP) enables us to evaluate and recondition lungs whose functionality is doubtful, as well as to overcome the difficulties related to time and logistics.
METHODS
We report the case of uncontrolled DCD lungs successfully treated with an exceptionally prolonged EVLP. Because the donor's blood count and liver biopsy showed signs of possible leukemia, EVLP was protracted up to 17 h while waiting for immunohistochemical analyses to rule out this diagnosis; eventually, the results came back negative, and the lungs were judged suitable for transplantation.
RESULTS
The recipient was a 32-y-old male individual with cystic fibrosis, colonized by Pandoraea pnomenusa. Bilateral transplantation required central extracorporeal membrane oxygenation. The patient was extubated after 36 h and was discharged 21 d after the operation. Despite early recolonization by Pandoraea pnomenusa and airway complications requiring pneumatic dilatation, he is alive and has a satisfactory respiratory function 15 mo after transplantation.
CONCLUSIONS
Uncontrolled DCD represents a challenge due to both logistical issues and the complexity of graft evaluation before procurement. EVLP with cellular perfusate could be a valuable tool to overcome these limits. Nonetheless, caution should be exercised when interpreting the effects of this technique on airway healing.
Topics: Extracorporeal Circulation; Humans; Lung; Lung Transplantation; Male; Organ Preservation; Perfusion; Tissue Donors; Warm Ischemia
PubMed: 33496562
DOI: 10.1097/TP.0000000000003646 -
Microbiology Resource Announcements Jan 2020strain TF-18 was isolated from the roots of rice seedlings on selective medium containing four classes of antibiotics for isolation of Using Pacific Biosciences...
strain TF-18 was isolated from the roots of rice seedlings on selective medium containing four classes of antibiotics for isolation of Using Pacific Biosciences (PacBio) single-molecule real-time (SMRT) sequencing technology, we report here a complete genome of 5,499,432 bases, a GC content of 64.8%, and 4,849 coding sequences.
PubMed: 31896624
DOI: 10.1128/MRA.01008-19 -
Future Microbiology Nov 2019Genetic characterization of strains recovered from cystic fibrosis patients. The whole-genome sequence of 12 strains was determined using Illumina technology. The...
Genetic characterization of strains recovered from cystic fibrosis patients. The whole-genome sequence of 12 strains was determined using Illumina technology. The position of the strains within the genus was analyzed using selected partial gene sequences, core genome multi-locus sequence typing and average nucleotide identity analysis. Furthermore, the sequences were annotated. The results show that some strains previously identified as , , and belong to novel species. The strains did not harbor acquired antibiotic resistance genes but encoded an OXA-type ß-lactamase. The taxonomy of the genus needs to be revised.
Topics: Bacterial Typing Techniques; Burkholderiaceae; Cystic Fibrosis; DNA, Ribosomal; Genome, Bacterial; Gram-Negative Bacterial Infections; Humans; Multilocus Sequence Typing; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Whole Genome Sequencing; beta-Lactamases
PubMed: 31762328
DOI: 10.2217/fmb-2019-0038