Dolosigranulum pigrum en absceso corneal / Dolosigranulum pigrum in corneal abscess

Resumen Dolosigranulum pigrum es un coco gram positivo, anaerobio facultativo, que forma parte de la microbiota oral y del tracto respiratorio superior. Aunque los reportes de infecciones por este microorganismo son escasos, se lo ha asociado a un amplio espectro de enfermedades infecciosas. Se describe el caso de un hombre adulto con un absceso corneal del que se aisló D. pigrum. El microorganismo fue identificado por espectrometría de masas (MALDI-TOF MS) y secuenciación del gen 16S ARNr. A su vez, se logró la identificación presuntiva mediante pruebas fenotípicas claves, como la disposición en racimos en la coloración de Gram, la prueba negativa de la catalasa, la producción de pirrolidonil arilamidasa y leucina aminopeptidasa, el crecimiento en NaCl al 6,5% y la hidrólisis de esculina. Los datos de la literatura y el presente caso respaldan la asociación del microorganismo con infecciones oculares, a menudo de curso destructivo, principalmente en pacientes de edad avanzada.

Abstract Dolosigranulum pigrum is a gram-positive, facultatively anaerobic coccus, which is part of the oral and upper respiratory tract microbiota. Although reports of infections by this microorganism are scarce, it has been associated with a wide spectrum of infectious diseases. The case of an elderly man with a lower corneal abscess, in which Dolosigranulum pigrum was isolated, is described. The microorganism was identified by mass spectrometry (MALDI-TOF MS) and by the sequencingof the 16S rRNAgene. Furthermore, the presumptive identification of the causative agent was achieved by using key phenotypic tests such as the cluster arrangement in Gram stain, the negative catalase test, the production of pyrrolidonyl arylamidase and leucine aminopeptidase activity, the growth in 6.5% NaCl and esculin hydrolysis. The data from the literature (and the present case) support the association of the microorganism with ocular infections, which often take a destructive course, mainly in elderly patients.

[Dolosigranulum pigrum in corneal abscess]. / Dolosigranulum pigrum en absceso corneal.

Dolosigranulum pigrum is a gram-positive, facultatively anaerobic coccus, which is part of the oral and upper respiratory tract microbiota. Although reports of infections by this microorganism are scarce, it has been associated with a wide spectrum of infectious diseases. The case of an elderly man with a lower corneal abscess, in which Dolosigranulum pigrum was isolated, is described. The microorganism was identified by mass spectrometry (MALDI-TOF MS) and by the sequencing of the 16S rRNA gene. Furthermore, the presumptive identification of the causative agent was achieved by using key phenotypic tests such as the cluster arrangement in Gram stain, the negative catalase test, the production of pyrrolidonyl arylamidase and leucine aminopeptidase activity, the growth in 6.5% NaCl and esculin hydrolysis. The data from the literature (and the present case) support the association of the microorganism with ocular infections, which often take a destructive course, mainly in elderly patients.

Corynebacterium phoceense - a rare Corynebacterium species isolated from a urine sample.

Corynebacterium spp. are Gram-positive rods that are recognized to cause opportunistic diseases under certain predisposing clinical conditions. Some species have been described in urinary tract infections. In this report we document a new episode of urinary tract infection caused by Corynebacterium phoceense and describe the whole-genome sequencing, phenotypic characteristics and mass spectra obtained by matrix-assisted desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Based on genome identification and DNA-to-DNA hybridization, we can assume that our strain is the second isolate of C. phoceense to be described in a urine sample. No other infectious diseases have been reported to be associated with this species.

Role of Tonsillar Chronic Inflammation and Commensal Bacteria in the Pathogenesis of Pediatric OSA.

Immune responses at the boundary between the host and the world beyond are complex and mucosal tissue homeostasis relies on them. Obstructive sleep apnea (OSA) is a syndrome suffered by children with hypertrophied tonsils. We have previously demonstrated that these tonsils present a defective regulatory B cell (Breg) compartment. Here, we extend those findings by uncovering the crucial role of resident pro-inflammatory B and T cells in sustaining tonsillar hypertrophy and hyperplasia by producing TNFα and IL17, respectively, in ex vivo cultures. Additionally, we detected prominent levels of expression of CD1d by tonsillar stratified as well as reticular epithelium, which have not previously been reported. Furthermore, we evidenced the hypertrophy of germinal centers (GC) and the general hyperplasia of B lymphocytes within the tissue and the lumen of the crypts. Of note, such B cells resulted mainly (IgG/IgM)+ cells, with some IgA+ cells located marginally in the follicles. Finally, by combining bacterial culture from the tonsillar core and subsequent identification of the respective isolates, we determined the most prevalent species within the cohort of OSA patients. Although the isolated species are considered normal oropharyngeal commensals in children, we confirmed their capacity to breach the epithelial barrier. Our work sheds light on the pathological mechanism underlying OSA, highlighting the relevance taken by the host immune system when defining infection versus colonization, and opening alternatives of treatment.

Total nephrectomy following Corynebacterium coyleae urinary tract infection.

INTRODUCTION: Corynebacterium coyleae is a Gram-stain-positive non-lipophilic coryneform rod first described in blood samples and pleural fluid. There is scarce information about the clinical relevance of C. coyleae and none on complicated urinary tract infections has been described so far. CASE PRESENTATION: A 36-year-old woman with a history of chronic kidney failure, under thrice-weekly haemodialysis since 2014 due to polycystic kidney disease, presented with hypogastric pain, lower left quadrant pain and nausea. Since 1997, the patient had developed several episodes of urinary tract infection. On admission, the patient presented tenderness in the lower abdomen and fist positive lumbar percussion. Urine culture showed significant bacterial growth (>105 c.f.u. ml-1). Slightly glistening colonies of 1 mm in diameter were observed after a 24 h incubation. Gram staining showed coryneform Gram-stain-positive rods. The patient was diagnosed as having a complicated urinary tract infection. A bilateral nephrectomy was performed on the fourth day of hospitalization. Two samples of kidney tissue were sent for culture. Direct examination of the material revealed the presence of abundant inflammatory reaction and Gram-positive diphtheroid rods. The organism was identified using MALDI-TOF and conventional biochemical tests; in both isolates further identification was performed by PCR amplification and sequence analysis of the rpoB gene as Corynebacterium coyleae. CONCLUSIONS: C. coyleae is an infrequent species among the genus Corynebacterium that should be considered as an emerging pathogen that can be involved in nosocomial infections and complicated urinary tract infections.

Comparison between disk diffusion and agar dilution methods to determine in vitro susceptibility of Corynebacterium spp. clinical isolates and update of their susceptibility.

OBJECTIVES: Although Corynebacterium spp. are part of the microbiota of the skin and mucous membranes, human infections caused by Corynebacterium spp. have been reported and the multidrug resistance pattern of the recovered isolates was emphasised. Due to the usefulness of disk diffusion in daily practice, the purpose of this study was to compare disk diffusion with agar dilution to determine disk diffusion breakpoints and to review the antimicrobial susceptibility of the most frequent Corynebacterium spp. isolated in clinical samples. METHODS: Susceptibility to 20 antimicrobial agents of 143 Corynebacterium spp. isolates recovered from relevant clinical samples was determined. Comparison between the disk diffusion and agar dilution methods for eight antimicrobial agents was performed to establish new breakpoints using simple linear regression analysis. RESULTS: All of the isolates tested were susceptible to vancomycin, minocycline and linezolid. A typical susceptibility profile to ß-lactam antibiotics among the different species included was not observed. Almost all isolates showed resistance to macrolides and lincosamides. Using a simple linear regression method, it was possible to establish breakpoints for penicillin, erythromycin, clindamycin, gentamicin and ciprofloxacin. However, the low correlation coefficient obtained for vancomycin, minocycline and trimethoprim/sulfamethoxazole did not allow establishment of breakpoints for the disk diffusion method. CONCLUSION: The disk diffusion method could only be used to evaluate susceptibility to penicillin, erythromycin, clindamycin, gentamicin and ciprofloxacin. These data show that the presence of a Corynebacterium spp. isolate in a clinical sample demands the performance of antimicrobial susceptibility testing since the susceptibility profile is not predictable.

Isolation of Kerstersia gyiorum from a patient with cholesteatomatous chronic otitis media.

We describe the first case of a Kerstersia gyiorum strain isolated from a patient with cholesteatomatous chronic otitis media. We emphasize the isolation of members of the family Alcaligenaceae in serious infections and unusual sites and the importance of polyphasic identification addressing the definitive identification.

First report of an extensively drug-resistant VIM-2 metallo-ß-lactamase-producing Brevundimonas diminuta clinical isolate.

In the literature, only three Brevundimonas diminuta environmental isolates carrying metallo-ß-lactamase genes were recently published. However, so far, no B. diminuta clinical isolates carrying these carbapenem resistance genes have been described. Here we report the first VIM-2 metallo-ß-lactamase-producing B. diminuta clinical isolate obtained from an immunocompromised patient.

Recurrent urinary infection with Bifidobacterium scardovii.

Bifidobacterium species are difficult to identify and may be underreported or not recovered by many laboratories because of their slow growth. We emphasize the importance of the Gram stain in urine samples and the addition of enriched media and enhanced atmosphere over time for urine cultures with pyuria. This is the first report of a Bifidobacterium scardovii recurrent urinary infection in an elderly woman.