-
Microbiology Spectrum May 2024The complex (Bcc) is a group of Gram-negative opportunistic bacteria often associated with fatal pulmonary infections in patients with impaired immunity, particularly...
Mutation of , encoding homogentisate 1,2-dioxygenase, is responsible for pyomelanin production but does not impact the virulence of in a chronic granulomatous disease mouse lung infection.
The complex (Bcc) is a group of Gram-negative opportunistic bacteria often associated with fatal pulmonary infections in patients with impaired immunity, particularly those with cystic fibrosis (CF) and chronic granulomatous disease (CGD). Some Bcc strains are known to naturally produce pyomelanin, a brown melanin-like pigment known for scavenging free radicals; pigment production has been reported to enable Bcc strains to overcome the host cell oxidative burst. In this work, we investigated the role of pyomelanin in resistance to oxidative stress and virulence in strains J2315 and K56-2, two epidemic CF isolates belonging to the ET-12 lineage. We previously reported that a single amino acid change from glycine to arginine at residue 378 in homogentisate 1,2-dioxygenase (HmgA) affects the pigment production phenotype: pigmented J2315 has an arginine at position 378, while non-pigmented K56-2 has a glycine at this position. Herein, we performed allelic exchange to generate isogenic non-pigmented and pigmented strains of J2315 and K56-2, respectively, and tested these to determine whether pyomelanin contributes to the protection against oxidative stress as well as in a respiratory infection in CGD mice . Our results indicate that the altered pigment phenotype does not significantly impact these strains' ability to resist oxidative stress with HO and NO and did not change the virulence and infection outcome in CGD mice suggesting that other factors besides pyomelanin are contributing to the pathophysiology of these strains.IMPORTANCEThe complex (Bcc) is a group of Gram-negative opportunistic bacteria that are often associated with fatal pulmonary infections in patients with impaired immunity, particularly those with cystic fibrosis and chronic granulomatous disease (CGD). Some Bcc strains are known to naturally produce pyomelanin, a brown melanin-like pigment known for scavenging free radicals and overcoming the host cell oxidative burst. We investigated the role of pyomelanin in strains J2315 (pigmented) and K56-2 (non-pigmented) and performed allelic exchange to generate isogenic non-pigmented and pigmented strains, respectively. Our results indicate that the altered pigment phenotype does not significantly impact these strains' ability to resist HO or NO and did not alter the outcome of a respiratory infection in CGD mice . These results suggest that pyomelanin may not always constitute a virulence factor and suggest that other features are contributing to the pathophysiology of these strains.
PubMed: 38809005
DOI: 10.1128/spectrum.00410-24 -
Emerging Infectious Diseases Jun 2024Burkholderia semiarida was previously identified solely as a plant pathogen within the Burkholderia cepacia complex. We present a case in China involving recurrent...
Burkholderia semiarida was previously identified solely as a plant pathogen within the Burkholderia cepacia complex. We present a case in China involving recurrent pneumonia attributed to B. semiarida infection. Of note, the infection manifested in an immunocompetent patient with no associated primary diseases and endured for >3 years.
Topics: Humans; Burkholderia Infections; China; Burkholderia; Recurrence; Male; Immunocompetence; Anti-Bacterial Agents; Middle Aged; Pneumonia, Bacterial
PubMed: 38782141
DOI: 10.3201/eid3006.231676 -
International Journal of... Jan 2024In patients with cystic fibrosis (CF), representatives of the fast-growing Mycobacterium abscessus complex (MABSc) are often distinguished, but the culture of the...
BACKGROUND
In patients with cystic fibrosis (CF), representatives of the fast-growing Mycobacterium abscessus complex (MABSc) are often distinguished, but the culture of the material taken from such patients increases the growth time. We analyzed the terms of cultivation of MABSc representatives on dense nutrient media and also evaluated the productivity of a modified nutrient medium based on agar for the isolation of Burkholderia cepacia complex (BCC).
METHODS
Sixty-four strains of MABSc isolated from patients with CF and suspected tuberculosis were analyzed. The material from the patients was cultured on a universal chromogenic medium, 5% blood agar, yolk-salt agar, selective medium for isolation of BCC, and Löwenstein-Jensen medium. The cultures were incubated for 5 days (37°C, aerobic conditions), after for 23 days (28°C, aerobic conditions). The productivity of the developed nutrient medium was evaluated by the number of cells that gave visible growth after culturing 0.1 mL of a bacterial suspension of 103 CFU/mL.
RESULTS
76.8% of the strains grew in a 2-week period, and 23.2% of the strains were obtained at a later date from 18 to 28 days (average: 21.23 days). The modified medium with a concentration of 240 mg of iron (III) polymaltose hydroxide proved to be the most optimal for the isolation of MABSc.
CONCLUSION
When using a chromogenic medium for culture material from patients with CF, it is necessary to extend incubation up to 28 days to increase the probability of MABSc isolation. The modified BCC medium showed a good selectivity result but required further investigation.
Topics: Humans; Cystic Fibrosis; Culture Media; Mycobacterium abscessus; Mycobacterium Infections, Nontuberculous; Time Factors; Bacteriological Techniques; Burkholderia cepacia complex
PubMed: 38771277
DOI: 10.4103/ijmy.ijmy_205_23 -
Heliyon May 2024The complex (Bcc) is a gram-negative bacillus, which is intrinsically resistant to several used antibiotics, and is now recognized as a group of opportunistic pathogens...
The complex (Bcc) is a gram-negative bacillus, which is intrinsically resistant to several used antibiotics, and is now recognized as a group of opportunistic pathogens in Cystic Fibrosis patients. Here, for the first time, we report the case of a patient with New Delhi metallo β-lactamase (NDM)-positive Bcc lower respiratory tract infection in Iran. The patient was a 57-year-old male admitted to our hospital due to breathlessness, with a history of pulmonary thromboembolism and hypertension. On day 14, the patient underwent bronchoscopy and a bronchoalveolar lavage (BAL) specimen was taken. BAL culture grew Bcc. The drug resistance analysis showed positive NDM resistance, with susceptibility to only quinolones, therefore, levofloxacin was prescribed to the patient. He was discharged from the hospital on the 20th day, 4 days after the initiation of levofloxacin therapy, and died at home on the fifth day after discharge. This is the first report of a lung infection caused by an extensively drug-resistant NDM-positive Bcc strain in Iran.
PubMed: 38770338
DOI: 10.1016/j.heliyon.2024.e30895 -
PloS One 2024The Burkholderia cepacia complex (Bcc) is the number one bacterial complex associated with contaminated Finished Pharmaceutical Products (FPPs). This has resulted in...
A culture-independent nucleic acid diagnostics method for use in the detection and quantification of Burkholderia cepacia complex contamination in aqueous finished pharmaceutical products.
The Burkholderia cepacia complex (Bcc) is the number one bacterial complex associated with contaminated Finished Pharmaceutical Products (FPPs). This has resulted in multiple healthcare related infection morbidity and mortality events in conjunction with significant FPP recalls globally. Current microbiological quality control of FPPs before release for distribution depends on lengthy, laborious, non-specific, traditional culture-dependent methods which lack sensitivity. Here, we present the development of a culture-independent Bcc Nucleic Acid Diagnostic (NAD) method for detecting Bcc contaminants associated with Over-The-Counter aqueous FPPs. The culture-independent Bcc NAD method was validated to be specific for detecting Bcc at different contamination levels from spiked aqueous FPPs. The accuracy in Bcc quantitative measurements was achieved by the high degree of Bcc recovery from aqueous FPPs. The low variation observed between several repeated Bcc quantitative measurements further demonstrated the precision of Bcc quantification in FPPs. The robustness of the culture-independent Bcc NAD method was determined when its accuracy and precision were not significantly affected during testing of numerous aqueous FPP types with different ingredient matrices, antimicrobial preservative components and routes of administration. The culture-independent Bcc NAD method showed an ability to detect Bcc in spiked aqueous FPPs at a concentration of 20 Bcc CFU/mL. The rapid (≤ 4 hours from sample in to result out), robust, culture-independent Bcc NAD method presented provides rigorous test specificity, accuracy, precision, and sensitivity. This method, validated with equivalence to ISO standard ISO/TS 12869:2019, can be a valuable diagnostic tool in supporting microbiological quality control procedures to aid the pharmaceutical industry in preventing Bcc contamination of aqueous FPPs for consumer safety.
Topics: Burkholderia cepacia complex; Drug Contamination; Pharmaceutical Preparations
PubMed: 38753829
DOI: 10.1371/journal.pone.0303773 -
Pathogens and Disease Feb 2024The development of sustainable alternatives to conventional antimicrobials is needed to address bacterial virulence while avoiding selecting resistant strains in a...
The development of sustainable alternatives to conventional antimicrobials is needed to address bacterial virulence while avoiding selecting resistant strains in a variety of fields, including human, animal, and plant health. Quorum sensing (QS), a bacterial communication system involved in noxious bacterial phenotypes such as virulence, motility, and biofilm formation, is of utmost interest. In this study, we harnessed the potential of the lactonase SsoPox to disrupt QS of human, fish, and plant pathogens. Lactonase treatment significantly alters phenotypes including biofilm formation, motility, and infection capacity. In plant pathogens, SsoPox decreased the production of plant cell wall degrading enzymes in Pectobacterium carotovorum and reduced the maceration of onions infected by Burkholderia glumae. In human pathogens, lactonase treatment significantly reduced biofilm formation in Acinetobacter baumannii, Burkholderia cepacia, and Pseudomonas aeruginosa, with the cytotoxicity of the latter being reduced by SsoPox treatment. In fish pathogens, lactonase treatment inhibited biofilm formation and bioluminescence in Vibrio harveyi and affected QS regulation in Aeromonas salmonicida. QS inhibition can thus be used to largely impact the virulence of bacterial pathogens and would constitute a global and sustainable approach for public, crop, and livestock health in line with the expectations of the One Health initiative.
Topics: Quorum Sensing; Animals; Humans; Virulence; Biofilms; Bacteria; Plant Diseases; Anti-Bacterial Agents
PubMed: 38724459
DOI: 10.1093/femspd/ftae009 -
Infection and Drug Resistance 2024To compare the epidemiological characteristics and drug resistance of isolated from blood cultures, and to provide data support and a scientific basis for the clinical...
OBJECTIVE
To compare the epidemiological characteristics and drug resistance of isolated from blood cultures, and to provide data support and a scientific basis for the clinical treatment and detection of hospital infections.
METHODS
The Hebei Province Antimicrobial Surveillance Network received 349 strains isolated from blood cultures reported by 83 hospitals, from 2016 to 2021. These strains were identified by MALDI-TOF MS and, the antibiotic sensitivity tests were carried out using the VITEK 2 COMPACT system. The 2023 Institute of Clinical and Laboratory Standardization drug-susceptibility breakpoints were used for drug susceptibility testing and the data were analyzed using WHONET5.6 software.
RESULTS
A total of 349 strains were isolated from 2016 to 2021, including 68 strains from secondary hospitals and 281 strains from tertiary hospitals. The ratios of male: female patients with bloodstream infections in all hospitals, secondary hospitals, and tertiary hospitals were 1.49:1 (209/140), 2.09:1 (46/22), and 1.38:1 (163/118), respectively. Most strains were isolated in intensive care units (ICUs), followed by internal medicine departments, accounting for 49.57% (173/349) and 22.92% (80/349), respectively. Regarding the age distribution, most patients were elderly (>65 years, 57.59%, 201/349), with numbers of patients gradually declining with decreasing of age. The resistance rates for levofloxacin, ceftazidime, and sulfamethoxazole decreased over the 6-year period (P<0.05), while there were no significant changes in the resistance rates for meropenem, chloramphenicol, and minocycline (P>0.05). There was no significant difference in drug-resistance rates between secondary and tertiary hospitals (P>0.05).
CONCLUSION
Attention should be paid to bloodstream infections caused by , especially elderly patients and patients admitted to the ICU. The difficult treatment characteristics of bloodstream infections mean that laboratories and clinicians should pay careful attention to drug resistance to provide a basis for their prevention and empirical treatment.
PubMed: 38715964
DOI: 10.2147/IDR.S457314 -
Microbiology Spectrum May 2024Across the Burkholderia genus -linked protein glycosylation is highly conserved. While the inhibition of glycosylation has been shown to be detrimental for virulence in...
UNLABELLED
Across the Burkholderia genus -linked protein glycosylation is highly conserved. While the inhibition of glycosylation has been shown to be detrimental for virulence in complex species, such as , little is known about how specific glycosylation sites impact protein functionality. Within this study, we sought to improve our understanding of the breadth, dynamics, and requirement for glycosylation across the glycoproteome. Assessing the glycoproteome across different culture media using complementary glycoproteomic approaches, we increase the known glycoproteome to 141 glycoproteins. Leveraging this repertoire of glycoproteins, we quantitively assessed the glycoproteome of using Data-Independent Acquisition (DIA) revealing the glycoproteome is largely stable across conditions with most glycoproteins constitutively expressed. Examination of how the absence of glycosylation impacts the glycoproteome reveals that the protein abundance of only five glycoproteins (BCAL1086, BCAL2974, BCAL0525, BCAM0505, and BCAL0127) are altered by the loss of glycosylation. Assessing Δ (ΔBCAL0525), Δ (ΔBCAL0127), and ΔBCAM0505 strains, we demonstrate the loss of FliF, and to a lesser extent MotB, mirror the proteomic effects observed in the absence of glycosylation in Δ. While both MotB and FliF are essential for motility, we find loss of glycosylation sites in MotB or FliF does not impact motility supporting these sites are dispensable for function. Combined this work broadens our understanding of the glycoproteome supporting that the loss of glycoproteins in the absence of glycosylation is not an indicator of the requirement for glycosylation for protein function.
IMPORTANCE
is an opportunistic pathogen of concern within the Cystic Fibrosis community. Despite a greater appreciation of the unique physiology of gained over the last 20 years a complete understanding of the proteome and especially the O-glycoproteome, is lacking. In this study, we utilize systems biology approaches to expand the known glycoproteome as well as track the dynamics of glycoproteins across growth phases, culturing media and in response to the loss of glycosylation. We show that the glycoproteome of is largely stable across conditions and that the loss of glycosylation only impacts five glycoproteins including the motility associated proteins FliF and MotB. Examination of MotB and FliF shows, while these proteins are essential for motility, glycosylation is dispensable. Combined this work supports that glycosylation can be dispensable for protein function and may influence protein properties beyond stability.
PubMed: 38709084
DOI: 10.1128/spectrum.00346-24 -
Qatar Medical Journal 2024
PubMed: 38680415
DOI: 10.5339/qmj.2024.qitc.7 -
Vaccines Apr 2024complex infections remain life-threatening to cystic fibrosis patients, and due to the limited eradication efficiency of current treatments, novel antimicrobial...
complex infections remain life-threatening to cystic fibrosis patients, and due to the limited eradication efficiency of current treatments, novel antimicrobial therapies are urgently needed. Surface proteins are among the best targets to develop new therapeutic strategies since they are exposed to the host's immune system. A surface-shaving approach was performed using J2315 to quantitatively compare the relative abundance of surface-exposed proteins (SEPs) expressed by the bacterium when grown under aerobic and microaerophilic conditions. After trypsin incubation of live bacteria and identification of resulting peptides by liquid chromatography coupled with mass spectrometry, a total of 461 proteins with ≥2 unique peptides were identified. Bioinformatics analyses revealed a total of 53 proteins predicted as localized at the outer membrane (OM) or extracellularly (E). Additionally, 37 proteins were predicted as moonlight proteins with OM or E secondary localization. B-cell linear epitope bioinformatics analysis of the proteins predicted to be OM and E-localized revealed 71 SEP moieties with predicted immunogenic epitopes. The protegenicity higher scores of proteins BCAM2761, BCAS0104, BCAL0151, and BCAL0849 point out these proteins as the best antigens for vaccine development. Additionally, 10 of the OM proteins also presented a high probability of playing important roles in adhesion to host cells, making them potential targets for passive immunotherapeutic approaches. The immunoreactivity of three of the OM proteins identified was experimentally demonstrated using serum samples from cystic fibrosis patients, validating our strategy for identifying immunoreactive moieties from surface-exposed proteins of potential interest for future immunotherapies development.
PubMed: 38675780
DOI: 10.3390/vaccines12040398