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Frontiers in Microbiology 2020Pathogenic non-spore forming bacteria enter a dormant state under stressful conditions, which likely allows them to acquire resistance to various antibiotics. This work...
Pathogenic non-spore forming bacteria enter a dormant state under stressful conditions, which likely allows them to acquire resistance to various antibiotics. This work revealed the efficient formation of dormant "non-culturable" (NC) cells in stationary phase upon gradual acidification of the growth medium. Such cells were unable to form colonies and existed in a prolonged stationary phase. At an early stage of dormancy (approximately 14 days post-inoculation), dormant cells are able for resuscitation in liquid medium. However, those stored for long time in dormant state needed addition of supernatant taking from active cultures for successful resuscitation. NC cells possessed low RNA synthesis and significant tolerance to antibiotics (rifampicin and vancomycin). They also accumulated free porphyrins, and 5-aminolevulinic acid addition enhanced free porphyrin accumulation which makes them potentially sensitive to photodynamic inactivation (PDI). PDI of dormant bacteria was accomplished by exposing cells to a 565 nm wavelength of light using a SOLIS-4C light-emitting diode for 60 min. This revealed that increased porphyrin concentrations were correlated with elevated PDI sensitivity. Results shown here demonstrate the potential utility of employing PDI to minimize levels of dormant, persistent corynebacteria and the dormancy model developed here may be useful for finding new drugs and techniques for combatting persistent corynebacteria.
PubMed: 33391228
DOI: 10.3389/fmicb.2020.605899 -
Antibiotics (Basel, Switzerland) Jul 2020is a commensal bacterium that colonizes human skin, and it is part of the normal bacterial flora. In non-risk subjects, it can be the cause of bad body smell due to the...
is a commensal bacterium that colonizes human skin, and it is part of the normal bacterial flora. In non-risk subjects, it can be the cause of bad body smell due to the generation of volatile odorous metabolites, especially in the wet parts of the body that this bacterium often colonizes (i.e., groin and axillary regions). Importantly, in the last few decades, there have been increasing cases of serious infections provoked by this bacterium, especially in immunocompromised or hospitalized patients who have undergone installation of prostheses or catheters. The ease in developing resistance to commonly-used antibiotics (i.e., glycopeptides) has made the search for new antimicrobial compounds of clinical importance. Here, for the first time, we characterize the antimicrobial activity of some selected frog skin-derived antimicrobial peptides (AMPs) against by determining their minimum inhibitory and bactericidal concentrations (MIC and MBC) by a microdilution method. The results highlight esculentin-1b(1-18) [Esc(1-18)] and esculentin-1a(1-21) [Esc(1-21)] as the most active AMPs with MIC and MBC of 4-8 and 0.125-0.25 µM, respectively, along with a non-toxic profile after a short- and long-term (40 min and 24 h) treatment of mammalian cells. Overall, these findings indicate the high potentiality of Esc(1-18) and Esc(1-21) as (i) alternative antimicrobials against infections and/or as (ii) additives in cosmetic products (creams, deodorants) to reduce the production of bad body odor.
PubMed: 32722535
DOI: 10.3390/antibiotics9080448 -
Emerging Infectious Diseases Dec 2021To determine differences in clinical characteristics of patients with bacteremia caused by , , and other species of , we retrospectively reviewed medical records of... (Review)
Review
To determine differences in clinical characteristics of patients with bacteremia caused by , , and other species of , we retrospectively reviewed medical records of patients in Japan who had bacteremia during January 2014–May 2020. Of the 115 records evaluated, 60 (52%) were cases of true bacteremia and 55 (48%) were cases of contamination. Proportions of true bacteremia cases caused by (70%) and by (71%) were significantly higher than those caused by other species of (9%). These 2 organisms were commonly detected in blood cultures of patients with hematologic malignancies and neutropenia. The mortality rates at 90 days were 34% (), 30% (), and 0 (other species). Given the high mortality rates, assessing true bacteremia when or is detected in blood cultures, especially in patients with hematologic malignancy, is warranted.
Topics: Anti-Bacterial Agents; Bacteremia; Corynebacterium; Corynebacterium Infections; Humans; Japan
PubMed: 34812137
DOI: 10.3201/eid2712.210473 -
Cureus Sep 2021is a rare cause of prosthetic joint infections (PJIs) and infection after fracture fixation (IAFF). We present a case of a patient who developed associated IAFF three...
is a rare cause of prosthetic joint infections (PJIs) and infection after fracture fixation (IAFF). We present a case of a patient who developed associated IAFF three weeks after his fracture fixation. Due to its slow-growing nature, surgical cultures remained negative after 72 hours and grew only on day 5. We highlight that physicians should have -associated infection in their differential in such cases, especially when the cultures remain negative after 72 hours. We also review the literature of PJI and implant-associated infection with and discuss the antibiotic resistance patterns and some microbiological considerations associated with
PubMed: 34650854
DOI: 10.7759/cureus.17676 -
Open Forum Infectious Diseases Jul 2022periprosthetic joint infection (PJI) is a poorly described infectious syndrome. Prior studies included cases of polymicrobial infections. This series describes the...
BACKGROUND
periprosthetic joint infection (PJI) is a poorly described infectious syndrome. Prior studies included cases of polymicrobial infections. This series describes the clinical characteristics, management, and outcomes of monomicrobial PJI.
METHODS
We queried the Mayo Clinic Total Joint Registry for cases of monomicrobial knee and hip PJI in adults (age ≥18 years) between 2010 and 2019.
RESULTS
A total of 20 (1%) out of 2067 PJI cases met our inclusion criteria. Most were males (55%), and the median age was 64 years. Seventy percent had chronic symptoms (>4 weeks). PJI was delayed to late (>3 months postimplantation) in 90%. Three species were identified: (70%), (20%), and (10%). All tested isolates were susceptible to vancomycin (100%) and linezolid (100%), and most had a minimum inhibitory concentration ≤0.06 mcg/mL to daptomycin (75%). Other agents were less reliable, with high resistance to oral agents commonly used for suppression. Nineteen patients were treated: 37% debridement and implant retention (DAIR), 47% 2-stage exchange, and 16% resection without reimplantation. Of these, failure occurred in 29%, 11%, and 0%, respectively.
CONCLUSIONS
PJIs pose a therapeutic challenge due to limited antimicrobial armamentarium and undefined optimal surgical intervention. Vancomycin and linezolid remain the most reliable agents for treatment. DAIR may be attempted for acute PJI, but verification of durable chronic suppression options will be critical for this approach.
PubMed: 35873283
DOI: 10.1093/ofid/ofac193 -
European Heart Journal. Case Reports Dec 2020The Modified Duke criteria is an important structured schematic for the diagnosis of infective endocarditis (IE). is a rare cause of IE that is often resistant to...
BACKGROUND
The Modified Duke criteria is an important structured schematic for the diagnosis of infective endocarditis (IE). is a rare cause of IE that is often resistant to standard IE anti-microbials. We present a case of IE, fulfilling the Modified Duke pathological criteria.
CASE SUMMARY
A 50-year-old male presented with left leg peripheral vascular disease with septic changes requiring amputation. Routine echocardiography post-amputation demonstrated severe aortic valve regurgitation with vegetations that required valve replacement. Two initial blood cultures from a single venepuncture showed which was treated with penicillin G prior to surgery. Subsequent aortic valve tissue cultured with suggestive IE histological valvular changes and was successfully treated on a prolonged course of vancomycin.
DISCUSSION
This is the first IE case diagnosed on heart valvular tissue culture and highlights the importance for the fulfilment of the Modified Duke criteria in diagnosing left-sided IE. Mixed infection IE is rare, and this case possibly represents an unmasking of resistant IE following initial treatment of penicillin G.
PubMed: 33447720
DOI: 10.1093/ehjcr/ytaa365 -
Cureus Jun 2020is a multidrug-resistant gram-positive bacterium of the human skin flora and one of the most clinically important nondiphtherial corynebacteria in the acute care...
is a multidrug-resistant gram-positive bacterium of the human skin flora and one of the most clinically important nondiphtherial corynebacteria in the acute care setting. can cause different forms of infections, especially in immunocompromised patients with underlying risk factors and comorbidities. was initially described in 1976 as a highly resistant coryneform bacteria causing severe sepsis in patients with hematologic malignancies and profound neutropenia. infection has also been reported in the setting of endocarditis, septicemia, meningitis, pneumonia, and soft tissue infections. Management of disseminated infection in immunocompromised cancer patients can be challenging due to its high virulence and rapid skin colonization. We present two cases of disseminated infection in patients with acute myelogenous leukemia (AML) and underlying comorbidities. Both patients presented with neutropenic fever resistant to initial standard empiric antibiotic therapy.
PubMed: 32714702
DOI: 10.7759/cureus.8764 -
IDCases 2018Diphtheroids are gram-positive pleomorphic bacilli in the family of Coryneform bacteria. These organisms are present as part of the human flora. Past practice habits had...
Diphtheroids are gram-positive pleomorphic bacilli in the family of Coryneform bacteria. These organisms are present as part of the human flora. Past practice habits had been to consider them as contaminants when isolated from clinical samples. is one of the most clinically important nondiphtherial Corynebacteria that can cause different forms of infections specifically in patients with underlying risk factors and co-morbidities including immunocompromised subjects. Through this article, we present a 67-year-old gentleman with extensive co-morbidities including heart failure with reduced ejection fraction and ESRD on hemodialysis through a femoral catheter who presented with chest pain and fatigue. Further investigation confirmed diagnosis of . endocarditis. We go on to review previously reported cases of endocarditis and we will discuss different aspects of infection with a focus on microbiology, pathophysiology, and treatment.
PubMed: 29619320
DOI: 10.1016/j.idcr.2017.11.004 -
PloS One 2013Corynebacterium jeikeium, a resident of human skin, is often associated with multidrug resistant nosocomial infections in immunodepressed patients. C. jeikeium K411...
Corynebacterium jeikeium, a resident of human skin, is often associated with multidrug resistant nosocomial infections in immunodepressed patients. C. jeikeium K411 belongs to mycolic acid-containing actinomycetes, the mycolata and contains a channel-forming protein as judged from reconstitution experiments with artificial lipid bilayer experiments. The channel-forming protein was present in detergent treated cell walls and in extracts of whole cells using organic solvents. A gene coding for a 40 amino acid long polypeptide possibly responsible for the pore-forming activity was identified in the known genome of C. jeikeium by its similar chromosomal localization to known porH and porA genes of other Corynebacterium strains. The gene jk0268 was expressed in a porin deficient Corynebacterium glutamicum strain. For purification temporarily histidine-tailed or with a GST-tag at the N-terminus, the homogeneous protein caused channel-forming activity with an average conductance of 1.25 nS in 1M KCl identical to the channels formed by the detergent extracts. Zero-current membrane potential measurements of the voltage dependent channel implied selectivity for anions. This preference is according to single-channel analysis caused by some excess of cationic charges located in the channel lumen formed by oligomeric alpha-helical wheels. The channel has a suggested diameter of 1.4 nm as judged from the permeability of different sized hydrated anions using the Renkin correction factor. Surprisingly, the genome of C. jeikeium contained only one gene coding for a cell wall channel of the PorA/PorH type found in other Corynebacterium species. The possible evolutionary relationship between the heterooligomeric channels formed by certain Corynebacterium strains and the homooligomeric pore of C. jeikeium is discussed.
Topics: Bacterial Proteins; Cell Wall; Corynebacterium; Humans; Porins; Skin
PubMed: 24116064
DOI: 10.1371/journal.pone.0075651 -
Journal of Clinical Microbiology Aug 1994Levels of DNA relatedness were determined by performing DNA-DNA hybridization experiments (S1 nuclease procedure) with 13 human isolates exhibiting various antimicrobial...
Levels of DNA relatedness were determined by performing DNA-DNA hybridization experiments (S1 nuclease procedure) with 13 human isolates exhibiting various antimicrobial susceptibility patterns which had been identified as Corynebacterium jeikeium by classical tests and the API Coryne system and with reference strains of C. jeikeium and related taxa. Twelve of 13 isolates which formed three genomic groups showed between 22 and 75% relatedness with the type strain of C. jeikeium. One of these genomic groups included all the strains resistant to penicillin and gentamicin and is genomically related to the C. jeikeium type strain at the species level. In addition, the reference strain of "Corynebacterium genitalium" biotype II was found to belong to this genospecies and therefore can be considered as a synonym of C. jeikeium. In contrast, one isolate and the reference strains of "Corynebacterium pseudogenitalium" biotypes C-3 and C-4 which were assigned to C. jeikeium by the API Coryne system were less than 10% related to the C. jeikeium type strain. These nongenomically related strains can be differentiated from the jeikeium-related strains on the basis of positive acidification from fructose and growth under anaerobic conditions. Furthermore, these strains exhibited full susceptibility to penicillin whereas the strains related to the C. jeikeium type strain are resistant to or only moderately susceptible to penicillin. No genomic relationship was found between C. jeikeium-related strains and other lipophilic coryneforms, identified as Corynebacterium accolens or Corynebacterium group G or F. Our study demonstrates the necessity to perform the fructose fermentation test or respiratory-type test for the correct identification of lipophilic coryneforms as C. jeikeium. Although these strains show genomic diversity at the species level, in a practical aspect, biochemical properties as well as antimicrobial susceptibility may allow the classification of such isolates in this single taxon.
Topics: Bacterial Typing Techniques; Corynebacterium; Corynebacterium Infections; DNA, Bacterial; Drug Resistance, Microbial; Genetic Variation; Genome, Bacterial; Humans; Microbial Sensitivity Tests; Nucleic Acid Hybridization; Phenotype
PubMed: 7989533
DOI: 10.1128/jcm.32.8.1860-1865.1994