Corynebacteria are rare causative agents of infective endocarditis. This is a reported case of a destructive aorto-mitral infective endocarditis caused by
Arthrobacter woluwensis
. Microbial ...identification was achieved by 16S rRNA polymerase chain reaction on valve tissue samples. Outcome was favorable after surgical valve replacement and 4-week antibiotic treatment.
The identification of nonfermenting gram-negative bacilli isolated from cystic fibrosis (CF) patients is usually achieved by using phenotype-based techniques and eventually molecular tools. These ...techniques remain time-consuming, expensive, and technically demanding. We used a method based on matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) for the identification of these bacteria. A set of reference strains belonging to 58 species of clinically relevant nonfermenting gram-negative bacilli was used. To identify peaks discriminating between these various species, the profile of 10 isolated colonies obtained from 10 different passages was analyzed for each referenced strain. Conserved peaks with a relative intensity greater than 0.1 were retained. The spectra of 559 clinical isolates were then compared to that of each of the 58 reference strains as follows: 400 Pseudomonas aeruginosa, 54 Achromobacter xylosoxidans, 32 Stenotrophomonas maltophilia, 52 Burkholderia cepacia complex (BCC), 1 Burkholderia gladioli, 14 Ralstonia mannitolilytica, 2 Ralstonia pickettii, 1 Bordetella hinzii, 1 Inquilinus limosus, 1 Cupriavidus respiraculi, and 1 Burkholderia thailandensis. Using this database, 549 strains were correctly identified. Nine BCC strains and one R. mannnitolilytica strain were identified as belonging to the appropriate genus but not the correct species. We subsequently engineered BCC- and Ralstonia-specific databases using additional reference strains. Using these databases, correct identification for these species increased from 83 to 98% and from 94 to 100% of cases, respectively. Altogether, these data demonstrate that, in CF patients, MALDI-TOF-MS is a powerful tool for rapid identification of nonfermenting gram-negative bacilli.
Melioidosis is an endemic disease in southeast Asia and northern Australia caused by the saprophytic bacteria Burkholderia pseudomallei, with a high mortality rate. The clinical presentation is ...multifaceted, with symptoms ranging from acute septicemia to multiple chronic abscesses. Here, we report a chronic case of melioidosis in a patient who lived in Malaysia in the 70s and was suspected of contracting tuberculosis. Approximately 40 years later, in 2014, he was diagnosed with pauci-symptomatic melioidosis during a routine examination. Four strains were isolated from a single sample. They showed divergent morphotypes and divergent antibiotic susceptibility, with some strains showing resistance to trimethoprim-sulfamethoxazole and fluoroquinolones. In 2016, clinical samples were still positive for B. pseudomallei, and only one type of strain, showing atypical resistance to meropenem, was isolated.
We performed whole genome sequencing and RT-qPCR analysis on the strains isolated during this study to gain further insights into their differences. We thus identified two types of resistance mechanisms in these clinical strains. The first one was an adaptive and transient mechanism that disappeared during the course of laboratory sub-cultures; the second was a mutation in the efflux pump regulator amrR, associated with the overexpression of the related transporter.
The development of such mechanisms may have a clinical impact on antibiotic treatment. Indeed, their transient nature could lead to an undiagnosed resistance. Efflux overexpression due to mutation leads to an important multiple resistance, reducing the effectiveness of antibiotics during treatment.
Zoonotic species of
Capnocytophaga
genus belong to the oral microbiota of dogs and cats. They may be responsible for serious human infections, mainly after animal bites, with a high mortality rate. ...In France, only few cases have been reported and no multicenter study has been conducted. Our aim was to describe the French epidemiology of
Capnocytophaga
zoonosis. We conducted a multicenter (21 centers) retrospective non-interventional, observational study in France describing the epidemiology of
Capnocytophaga
zoonosis (
C. canimorsus
,
C. cynodegmi
,
C. canis
) over 10 years with regard to clinical and bacteriological data. From 2009 to 2018, 44 cases of
Capnocytophaga
zoonotic infections were described (
C. canimorsus
,
n
= 41;
C. cynodegmi
,
n
= 3). We observed an increase (2.5 times) in the number of cases over the study period (from the first to the last 5 years of the study). The most frequent clinical presentations were sepsis (
n
= 37), skin and soft tissue infections (
n
= 12), meningitis (
n
= 8), osteoarticular infections (
n
= 6), and endocarditis (
n
= 2). About one-third of patients with sepsis went into septic shock. Mortality rate was 11%. Mortality and meningitis rates were significantly higher for alcoholic patients (
p
= 0.044 and
p
= 0.006, respectively). Other comorbidities included smoking, splenectomy, diabetes mellitus, and immunosuppressive therapy are associated to zoonotic
Capnocytophaga
infection. Eighty-two percent of cases involved contact with dogs, mostly included bites (63%). Despite all isolates were susceptible to the amoxicillin-clavulanic acid combination, three of them were resistant to amoxicillin.
Abstract Alpha-enolase, also called non-neuronal enolase, belongs to a family of cytoplasmic and glycolytic enzymes. In addition to its glycolytic function, alpha-enolase exerts many other functions ...in eukaryotes and prokaryotes. Antibodies (Abs) against alpha-enolase have been detected in a large variety of infectious and autoimmune diseases. These Abs might arise as a consequence of a microbial infection or uncontrolled growth or proliferation of cells in specific organs in pathophysiological conditions. In infections, anti-alpha-enolase Abs could play a role in limiting microbial tissue invasion. In autoimmune and inflammatory diseases, anti-alpha-enolase Abs could induce endothelial injury through the generation of immune complexes and activation of the complement classical pathway, inhibit the binding of plasminogen to alpha-enolase with perturbations of the intravascular and pericellular fibrinolytic system, and induce cell death through an apoptotic process. However, further studies are needed to improve our knowledge on the pathogenic role of these Abs.
Bacteremia of unknown origin (BUO) are associated with increased mortality compared to those with identified sources. Microbiological data of those patients could help to characterize an appropriate ...empirical antibiotic treatment before bloodcultures results are available during sepsis of unknown origin. Based on the dashboard of our ward that prospectively records several parameters from each hospitalization, we report 101 community-acquired BUO selected among 1989 bacteremic patients from July 2005 to April 2016, BUO being defined by the absence of clinical and paraclinical infectious focus and no other microbiological samples retrieving the bacteria isolated from blood cultures. The in-hospital mortality rate was 9%. We retrospectively tested two antibiotic associations: amoxicillin-clavulanic acid + gentamicin (AMC/GM) and 3rd generation cephalosporin + gentamicin (3GC/GM) considered as active if the causative bacteria was susceptible to at least one of the two drugs. The mean age was 71 years with 67% of male, 31 (31%) were immunocompromised and 52 (51%) had severe sepsis. Eleven patients had polymicrobial infections. The leading bacterial species involved were Escherichia coli 25/115 (22%), group D Streptococci 12/115 (10%), viridans Streptococci 12/115 (10%) and Staphylococcus aureus 11/115 (9%). AMC/GM displayed a higher rate of effectiveness compared to 3GC/GM: 100/101 (99%) vs 94/101 (93%) (p = 0.04): one Enterococcus faecium strain impaired the first association, Bacteroides spp. and Enterococcus spp. the second. In case of community-acquired sepsis of unknown origin, AMC + GM should be considered.
We report eight cases of airway colonization by Geosmithia argillacea in patients with cystic fibrosis. This filamentous fungus, resembling members of the genera Penicillium and Paecilomyces, was ...identified by molecular analysis. All patients carried a mutation on each CFTR (cystic fibrosis transmembrane conductance regulator) allele, with at least one copy of the F508del mutation. The first isolation of this fungus occurred from F508del-homozygous patients at a younger age than in F508del-heterozygous patients. Before recovery of G. argillacea, all patients were treated with itraconazole; two of them had also received voriconazole for an Aspergillus fumigatus infection. However, antifungal susceptibility patterns showed high MICs of voriconazole for all isolates, and high MICs of amphotericin B and itraconazole for the majority of them, but mostly low minimum effective concentrations (MECs) of caspofungin. The appearance and persistence of G. argillacea in the airways were not associated with exacerbation of the disease. However, the clinical implications of G. argillacea, particularly in immunocompromised patients, remain a concern, particularly given recent observations suggesting that this fungus may also cause disseminated infections.
The aim of this multicentre study was to determine the in vitro susceptibility to anti-anaerobic antibiotics of Gram-positive anaerobic cocci (GPAC) isolates responsible for invasive infections in ...humans. A total of 133 GPAC isolates were collected in nine French hospitals from 2016 to 2020. All strains were identified to the species level (MALDI-TOF mass spectrometry, 16S rRNA sequencing). Minimum inhibitory concentrations (MICs) of amoxicillin, piperacillin, cefotaxime, imipenem, clindamycin, vancomycin, linezolid, moxifloxacin, rifampicin, and metronidazole were determined by the reference agar dilution method. Main erm-like genes were detected by PCR. The 133 GPAC isolates were identified as follows: 10 Anaerococcus spp., 49 Finegoldia magna, 33 Parvimonas micra, 30 Peptoniphilus spp., and 11 Peptostreptococcus anaerobius. All isolates were susceptible to imipenem, vancomycin (except 3 P. micra), linezolid and metronidazole. All isolates were susceptible to amoxicillin and piperacillin, except for P. anaerobius (54% and 45% susceptibility only, respectively). MICs of cefotaxime widely varied while activity of rifampicin, and moxifloxacin was also variable. Concerning clindamycin, 31 were categorized as resistant (22 erm(A) subclass erm(TR), 7 erm(B), 1 both genes and 1 negative for tested erm genes) with MICs from 8 to >32 mg/L. Although GPACs are usually susceptible to drugs commonly used for the treatment of anaerobic infections, antimicrobial susceptibility should be evaluated in vitro.
Nocardia takedensis was first isolated in 2005, from soil in Japan. We report here two cases of lymphangitis in France (2012-2017) caused by N. takedensis both occurring after skin injury while ...gardening, which enabled its inoculation. The two patients were immunocompromised and successfully treated by an antimicrobial agent active on the isolated strain, trimethoprim-sulfamethoxazole and amoxicillin-clavulanic acid for patient one and patient two, respectively. Our study along with previous ones supports the idea of a newly recognized cutaneous opportunistic pathogen and reinforces the recommendation of using gloves during soil exposure for immunocompromised patients. Lastly, according to data found in the literature, we would recommend trimethoprim-sulfamethoxazole as an efficient empirical antibiotic therapy in case of cutaneous infection caused by N. takedensis.
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