Bacterial resistance to minocycline after adjunctive minocycline microspheres during periodontal maintenance: A randomized clinical trial.

BACKGROUND: Despite widespread use, the impact of minocycline hydrochloride microspheres on the shifts of oral bacterial species resistant to minocycline remains unknown. This study aimed at examining the percentage and taxonomy of minocycline-resistant isolates in saliva and subgingival plaque samples before and after minocycline microspheres application in periodontitis patients during maintenance. METHODS: Patients received supra- and sub-gingival debridement with (test) or without (control) minocycline microspheres application to sites with probing depth >4 mm and were clinically monitored at baseline, 1, 3, and 6 months. Samples were collected at baseline, 1 and 6 months and analyzed via cultivation with or without 4 µg/mL minocycline. Percentage of resistant strains was determined by colony counting and taxonomy by checkerboard DNA-DNA hybridization. Significant clinical changes were sought with the Mann-Whitney test and differences in percentage of resistant isolates with the Friedman and Mann-Whitney tests. RESULTS: Groups showed similar clinical improvements. Mean percentage of resistant isolates rose at 1 month and decreased at 6 months in saliva and plaque samples in test group (P <0.05) but remained unchanged in control group. Percentage of resistant isolates of Gemella morbillorum and Eubacterium saburreum increased significantly at 6 months in both groups. Antibiotic resistance by Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Porphyromonas gingivalis was either absent or infrequent. CONCLUSION: Minocycline microspheres result in transient selection of minocycline resistant species in saliva and subgingival plaque samples.

Tuberculosis y una Gemella spp: Una combinación indeseable / Tuberculosis and a Gemella spp: An undesirable combination

El género Gemella spp corresponde a cocos gram positivos, anaerobios facultativos, catalasa negativos, no móviles y no formadores de esporas, usualmente comensales de la cavidad oral, que no suelen ser patógenos en pacientes inmunocompetentes. Sin embargo, puede comportarse como germen oportunista en pacientes inmunosuprimidos o con otros factores de riesgo como mala higiene dental, cirugía gastrointestinal, enfermedades metabólicas entre otras, y se asocia con endocarditis, meningitis y en menor medida compromiso pulmonar. La información respecto a la susceptibilidad antimicrobiana es limitada y se asemeja a la de S viridans, por lo que la penicilina y ampicilina son los medicamentos de elección, sin tener claridad en cuanto a duración del tratamiento, usualmente considerando llevar a 4 semanas o hasta el drenaje de la colección. Éste reporte de caso describe una paciente con tuberculosis en tratamiento, que desarrolla una infección invasiva con documentación de empiema y bacteriemia secundaria por Gemella morbillorum, representando la asociación poco común de ésta infección bacteriana con tuberculosis.

Gemella spp. corresponds to gram positive cocci, facultative anaerobes, negative catalase, non mobile and non spore producers, part of colonizing flora of the oral cavity that are not common pathogens in immunocompetent patients. Nevertheless it may behave as an opportunistic germ in immunosuppressed patients or with other risk factors that include bad dental hygiene, bowel surgery, and metabolic diseases among others. It's associated with infections such as endocarditis, meningitis and less frecuently can implicate the lung. The information regarding antimicrobial susceptibility is limited and resembles S viridans, so penicillin and ampicillin are the medications of choice, without being clear about the duration of treatment, usually giving 4 weeks or until collection drain. This case report describes a patient with known tuberculosis diagnosis and under treatment, that develops an invasive infection with empyema and secondary bloodstream infection by Gemella morbillorum, depicting a previously uncommon but described association of this bacterial infection with tuberculosis.

Pyogenic liver abscess caused by Gemella morbillorum.

Even though Gemella morbillorum infection (GMI) is rare in humans, it may nevertheless, cause endocarditis, meningitis, brain abscess, pleural empyema, nephritis, mediastinitis, and--occasionally--liver abscess. We are describing the case of a 64-years-old Caucasian male admitted with fever and abdominal pain. Laboratory parameters revealed inflammation signs, and instrumental examinations showed the presence of diverticula in the ascending colon. Abdominal ultrasound (US) and computer tomography (CT) showed two focal lesions in the right liver lobe. One had the characteristics of a simple cyst; the second was hypoechoic with a low density area, possibly containing necrotic material. US-guided needle biopsy was found negative for neoplastic cells, showing purulent infiltrate. Pus culture was found positive for GMI. Systemic antibiotic therapy coupled with repeated US-guided needle aspiration, induced the resolution of the hepatic abscess. Few cases have been reported of hepatic abscess caused by GMI in immunocompetent non-cirrhotic subjects.

A pesar de que la infección por Gemella morbillorum (GMI por el término en inglés) es poco común en seres humanos, puede causar endocarditis, meningitis, absceso cerebral, empiema pleural, nefritis, mediastinitis y en ocasiones, absceso hepático. Describimos el caso de un hombre caucásico de 64 años que ingresó con fiebre y dolor abdominal. Los parámetros de laboratorio revelaron signos de inflamación y los exámenes mostraron la presencia de divertículos en el colon ascendente. La ecografía abdominal (US) y la tomografía computarizada (CT) mostró dos lesiones focales en el lóbulo hepático derecho. Una presentó las características de un quiste simple; la segunda fue hipoecóica con una zona de baja densidad, que posiblemente contenía material necrótico. Biopsia con aguja guiada por US dio un resultado negativo para células neoplásicas, mostrando infiltrado purulento. Cultivo de pus fue encontrado positivo para GMI. Una terapia con antibióticos sistémicos, junto con aspiración repetida con aguja guiada por US indujo a la resolución del absceso hepático. Pocos casos se han reportado de absceso hepático causado por GMI en sujetos inmunocompetentes no cirróticos.

Pyogenic liver abscess caused by Gemella morbillorum / Absceso hepático piógeno causado por Gemella morbillorum

Even though Gemella morbillorum infection (GMI) is rare in humans, it may, nevertheless, cause endocarditis, meningitis, brain abscess, pleural empyema, nephritis, mediastinitis, and - occasionally - liver abscess. We are describing the case of a 64-year-old Caucasian male admitted with fever and abdominal pain. Laboratory parameters revealed inflammation signs, and instrumental examinations showed the presence of diverticula in the ascending colon. Abdominal ultrasound (US) and computer tomography (CT) showed two focal lesions in the right liver lobe. One had the characteristics of a simple cyst; the second was hypoechoic with a low density area, possibly containing necrotic material. US-guided needle biopsy was found negative for neoplastic cells, showing purulent infiltrate. Pus culture was found positive for GMI. Systemic antibiotic therapy, coupled with repeated US-guided needle aspiration, induced the resolution of the hepatic abscess. Few cases have been reported of hepatic abscess caused by GMI in immunocompetent non-cirrhotic subjects.

A pesar de que la infección por Gemella morbillorum (GMI, por el término en inglés) es poco común en seres humanos, puede causar endocarditis, meningitis, absceso cerebral, empiema pleural, nefritis, mediastinitis y en ocasiones, absceso hepático. Describimos el caso de un hombre caucásico de 64 años que ingresó con fiebre y dolor abdominal. Los parámetros de laboratorio revelaron signos de inflamación y los exámenes mostraron la presencia de divertículos en el colon ascendente. La ecografía abdominal (US) y la tomografía computarizada (CT) mostró dos lesiones focales en el lóbulo hepático derecho. Una presentó las características de un quiste simple; la segunda fue hipoecóica con una zona de baja densidad, que posiblemente contenía material necrótico. Biopsia con aguja guiada por US dio un resultado negativo para células neoplásicas, mostrando infiltrado purulento. Cultivo de pus fue encontrado positivo para GMI. Una terapia con antibióticos sistémicos, junto con aspiración repetida con aguja guiada por US indujo a la resolución del absceso hepático. Pocos casos se han reportado de absceso hepático causado por GMI en sujetos inmunocompetentes no cirróticos.

Investigation of cultivable bacteria isolated from longstanding retreatment-resistant lesions of teeth with apical periodontitis.

INTRODUCTION: The objective of this research was to investigate the presence of viable bacteria in tissue samples from persistent apical lesions and to correlate the microbiological findings with the histopathological diagnosis of the lesion. METHODS: Twenty persistent apical lesions associated with well-performed endodontic retreatment were collected. Tissue samples were processed through culture techniques including serial dilution, plating, aerobic and anaerobic incubation, and biochemical tests for microbial identification followed by histopathological diagnosis. RESULTS: Cysts were more frequently diagnosed (13/20). Strict anaerobic species predominated in both cysts (80.4% of the species detected) and granulomas (65% of the species detected). Viable gram-positive bacteria were frequently recovered from apical lesions (cysts = 70.6%, granulomas = 84.4%). Gemella morbillorum and Propionibacterium acnes were the most frequently recovered species from cysts and granulomas, respectively. At least 1 gram-positive bacterial species was present in almost every sample (cysts = 12/13, granulomas = 7/7). No significant correlation was found between histologic findings and bacterial species. CONCLUSIONS: In conclusion, although cysts were more frequent than granulomas in cases of failure of endodontic retreatment, bacteria were isolated from both types of lesions, with a predominance of gram-positive species, suggesting that these species can survive outside the root canal and might be related to the persistence of the pathological process even after accurate endodontic retreatment.

Subgingival biodiversity in subjects with uncontrolled type-2 diabetes and chronic periodontitis.

BACKGROUND AND OBJECTIVE: There is a bidirectional relationship between periodontal disease and type-2 diabetes mellitus (DM). Inflammatory mediators may negatively affect glycemic control, and increased glucose levels and resultant glycation end-products may alter the host response against bacterial infection. However, no agreement has been reached regarding the effect of DM on periodontal subgingival microbiota. Therefore, the purpose of the present study was to compare the subgingival biodiversity in deep periodontal pockets of subjects with chronic periodontitis and either uncontrolled type-2 diabetes or no diabetes using 16S rRNA gene cloning and sequencing. MATERIAL AND METHODS: Twelve subjects with uncontrolled type-2 diabetes (glycated hemoglobin > 8%) and eleven nondiabetic subjects presenting severe and generalized chronic periodontitis were selected. Subgingival biofilm from periodontal pockets > 5 mm were assessed using the 16S rRNA gene cloning and sequencing technique. RESULTS: Significant differences were observed in subgingival microbiota between diabetic and nondiabetic subjects. Diabetic subjects presented higher percentages of total clones of TM7, Aggregatibacter, Neisseria, Gemella, Eikenella, Selenomonas, Actinomyces, Capnocytophaga, Fusobacterium, Veillonella and Streptococcus genera, and lower percentages of Porphyromonas, Filifactor, Eubacterium, Synergistetes, Tannerella and Treponema genera than nondiabetic individuals (p < 0.05). Moreover, some phylotypes, such as Fusobacterium nucleatum, Veillonella parvula, V. dispar and Eikenella corrodens were detected significantly more often in diabetic subjects than in nondiabetic subjects (p < 0.05). CONCLUSION: Subjects with uncontrolled type-2 diabetes and chronic periodontitis presented significant dissimilarities in subgingival biodiversity compared with nondiabetic subjects.

Bacterial diversity in the saliva of patients with different oral hygiene indexes.

The objective of the present study was to evaluate the bacterial diversity in the saliva of patients with different oral hygiene indexes using of two 16S rRNA gene libraries. Each library was composed of samples from patients with different averages of the differentiated Silness-Löe biofilm index: the first library (A) with an index between 1.0 and 3.0 (considered a high index) and the second library (B) between 0 and 0.5 (considered a low index). Saliva DNA was extracted and the 16S rRNA gene was amplified and cloned. The obtained sequences were compared with those stored at NCBI and RDP GenBank. The saliva of patients with high index presented five known genera - Streptococcus, Granulicatella, Gemella, Veillonella and Peptostreptococcus - and 33.3% of nonculturable bacteria grouped into 23 operational taxonomic units (OTUs). The saliva of patients with low index differed significantly from the first library (p=0.000) and was composed of 42 OTUs distributed into 11 known genera - Streptococcus, Granulicatella, Gemella, Veillonella, Oribacterium, Haemophilus, Escherichia, Neisseria, Prevotella, Capnocytophaga, Actinomyces - including 24.87% of nonculturable bacteria. It was possible to conclude that there is greater bacterial diversity in the saliva of patients with low dental plaque in relation to patients with high dental plaque.

Empiemas pleurales por Gemella spp: una etiología no tan infrecuente / Pleural empyema due to Gemella spp: Report of 12 cases

Background: Gemella genus bacteria can produce localized or generalized severe infections, but very rarely they have been described as causingpulmonary infections or pleural empyemas. Aim: To characterize patients with empyema caused by Gemella genus bacteria. Material and Methods: The database of a Microbiology laboratory of a Spanish hospital was reviewed, searchingfor Gemella positive cultures ofpleural effusions in a period offive years. Results: We identified 12 patients (11 males) with Gemella spp pleural empyema. Eight were infected with G. haemolysans and four with G. morbillorum. All patients had predisposingfactors such as poor oral hygiene, smoking, chronic cardiovascular or respiratory disease, alcoholism or malignancies. In ten cases, a thoracic drainage tube was placed with fibrinolysis in seven. One patient needed surgery because of a relapse of the empyema. Two patients died because of an advanced neoplasm, and the empyema was resolved in the rest. Conclusions: Gemella pleural empyema can occur and its isolation must not be seen as a contamination.

[Pleural empyema due to Gemella spp: report of 12 cases]. / Empiemas pleurales por Gemella spp: una etiología no tan infrecuente.

BACKGROUND: Gemella genus bacteria can produce localized or generalized severe infections, but very rarely they have been described as causing pulmonary infections or pleural empyemas. AIM: To characterize patients with empyema caused by Gemella genus bacteria. MATERIAL AND METHODS: The database of a Microbiology laboratory of a Spanish hospital was reviewed, searching for Gemella positive cultures of pleural effusions in a period of five years. RESULTS: We identified 12 patients (11 males) with Gemella spp pleural empyema. Eight were infected with G. haemolysans and four with G. morbillorum. All patients had predisposing factors such as poor oral hygiene, smoking, chronic cardiovascular or respiratory disease, alcoholism or malignancies. In ten cases, a thoracic drainage tube was placed with fibrinolysis in seven. One patient needed surgery because of a relapse of the empyema. Two patients died because of an advanced neoplasm, and the empyema was resolved in the rest. CONCLUSIONS: Gemella pleural empyema can occur and its isolation must not be seen as a contamination.

Bacterial diversity in the saliva of patients with different oral hygiene indexes

The objective of the present study was to evaluate the bacterial diversity in the saliva of patients with different oral hygiene indexes using of two 16S rRNA gene libraries. Each library was composed of samples from patients with different averages of the differentiated Silness-Löe biofilm index: the first library (A) with an index between 1.0 and 3.0 (considered a high index) and the second library (B) between 0 and 0.5 (considered a low index). Saliva DNA was extracted and the 16S rRNA gene was amplified and cloned. The obtained sequences were compared with those stored at NCBI and RDP GenBank. The saliva of patients with high index presented five known genera - Streptococcus, Granulicatella, Gemella, Veillonella and Peptostreptococcus - and 33.3% of nonculturable bacteria grouped into 23 operational taxonomic units (OTUs). The saliva of patients with low index differed significantly from the first library (p=0.000) and was composed of 42 OTUs distributed into 11 known genera - Streptococcus, Granulicatella, Gemella, Veillonella, Oribacterium, Haemophilus, Escherichia, Neisseria, Prevotella, Capnocytophaga, Actinomyces - including 24.87% of nonculturable bacteria. It was possible to conclude that there is greater bacterial diversity in the saliva of patients with low dental plaque in relation to patients with high dental plaque.

O objetivo do presente estudo foi avaliar a diversidade bacteriana da saliva de pacientes com diferentes índices de higiene bucal através da construção de duas bibliotecas do gene 16S rRNA. Cada biblioteca foi composta por amostras de saliva de pacientes com índice de biofilme dental de Silness-Löe diferenciado, sendo a primeira (A) com índice de 1,0 a 3,0 (denominada de alto índice) e a segunda (B), entre 0 a 0,5 (denominada de baixo índice). O DNA da saliva foi extraído e o gene 16S rRNA foi amplificado, clonado e sequenciado. As sequências obtidas foram comparadas com aquelas armazenadas no GenBank do NCBI e RDP. A saliva de pacientes com alto índice de biofilme dental apresentou cinco gêneros conhecidos: Streptococcus, Granulicatella, Gemella, Veillonella e Peptostreptococcus e 33,3% de bactérias não-cultivadas, agrupados em 23 unidades taxonômicas operacionais (UTOs). A saliva de pacientes com baixo índice de biofilme dental, foi diferente significativamente da primeira (p=0,000) e foi composta de 42 UTOs, distribuídas em 11 gêneros conhecidos: Streptococcus, Granulicatella, Gemella, Veillonella, Oribacterium, Haemophilus, Escherichia, Neisseria, Prevotella, Capnocytophaga, Actinomyces, além de 24,87% de bactérias não-cultivadas. Pode-se concluir que existe maior diversidade bacteriana na saliva de pacientes com baixo índice de biofilme dental em relação a pacientes com alto índice de biofilme dental.