Streptococcus Constellatus Research Articles

Streptococcus constellatus Lymphadenitis in Chronic Granulomatous Disease

We read with interest the article titled “Streptococcal infections in Patients with Chronic Granulomatous Disease” by Falcone et al in August issue of the journal. We would like to report a case of lymphadenitis and pneumonia in a 14 year-old boy with chronic granulomatous disease due to Streptococcus constellatus a member of the Streptococcus anginosus group. This 14 year-old patient presented to our clinic with history of an enlarging neck mass for one week and two days of mild nonproductive cough. He did not have any constitutional symptoms. His physical examination demonstrated a 2×4 cm non-fluctuant and non-tender mass in the left anterior cervical area. The ultrasound of neck revealed conglomerated nodes without any suppuration. His chest xray demonstrated a left upper lobe consolidation. He underwent biopsy of the lymph node and bronchial alveolar lavage washings. Tissue cultures revealed alpha hemolytic colonies after 72 h on sheep blood agar, with a distinctive butterscotch smell. The API 20 Strep system (bioMerieux, Inc. Hazelwood, MO) did not yield an acceptable identification score. Matrix-assisted laser desorption/ionization time-offlight mass spectrometry (MALDI-TOF MS) using a MALDI-TOF MicroFlex LT mass spectrometer (Bruker Daltonics, Billerica, MA) identified Streptococcus constellatus with high score (∼2.0). We did not test our isolate for production of hydrogen peroxide. Histology of the node revealed acute and chronic inflammation and bronchial alveolar lavage washings yielded no growth. The patient is being treated with high dose amoxicillin and his clinical symptoms have improved. Our case not only extends the observations of Falcone et al but also records lymphadenitis due to Streptococcus anginosus group which is uncommon and has not been previously reported to our knowledge in CGD patients. It is however unclear in the few published cases of S.viridans infections in CGD , if further speciation was attempted or not. Our case not only illustrates the rarity of lymphadenitis due to S.anginosus group but also underscores the importance of observing the cultures for longer than 72 h.

Impact of Periodontal Therapy on the Subgingival Microbiota of Severe Periodontitis: Comparison Between Good Responders and Individuals With Refractory Periodontitis Using the Human Oral Microbe Identification Microarray

This study compares the changes to the subgingival microbiota of individuals with "refractory" periodontitis (RP) or treatable periodontitis (good responders [GR]) before and after periodontal therapy by using the Human Oral Microbe Identification Microarray (HOMIM) analysis. Individuals with chronic periodontitis were classified as RP (n = 17) based on mean attachment loss (AL) and/or >3 sites with AL ≥2.5 mm after scaling and root planing, surgery, and systemically administered amoxicillin and metronidazole or as GR (n = 30) based on mean attachment gain and no sites with AL ≥2.5 mm after treatment. Subgingival plaque samples were taken at baseline and 15 months after treatment and analyzed for the presence of 300 species by HOMIM analysis. Significant differences in taxa before and post-therapy were sought using the Wilcoxon test. The majority of species evaluated decreased in prevalence in both groups after treatment; however, only a small subset of organisms was significantly affected. Species that increased or persisted in high frequency in RP but were significantly reduced in GR included Bacteroidetes sp., Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella spp., Tannerella forsythia, Dialister spp., Selenomonas spp., Catonella morbi, Eubacterium spp., Filifactor alocis, Parvimonas micra, Peptostreptococcus sp. OT113, Fusobacterium sp. OT203, Pseudoramibacter alactolyticus, Streptococcus intermedius or Streptococcus constellatus, and Shuttlesworthia satelles. In contrast, Capnocytophaga sputigena, Cardiobacterium hominis, Gemella haemolysans, Haemophilus parainfluenzae, Kingella oralis, Lautropia mirabilis, Neisseria elongata, Rothia dentocariosa, Streptococcus australis, and Veillonella spp. were more associated with therapeutic success. Persistence of putative and novel periodontal pathogens, as well as low prevalence of beneficial species was associated with chronic refractory periodontitis.

Polymikrobieller Hirnabszess bei hereditärer hämorrhagischer Teleangiektasie (Morbus Osler)

A 38-year-old woman who suffered from migraine was admitted because of severe, worsening headache for 24 hours (dissimilar to the previous migraine attacks), with impaired vision and weakness of the right arm. Mild hemiparesis and expressive aphasia indicated an intracranial tumor. Cranial computed tomography revealed a focal lesion with a diameter of 2.5 cm in the left frontoparietal lobe, with signs of intracranial hypertension, indicating cerebral metastasis or an abscess. Magnetic resonance imaging confirmed the diagnosis of a brain abscess. An urgent craniotomy was performed and the abscess was evacuated. An empirical antibiotic combination with chloramphenicole and metronidazole (switched to cefotaxime because of thrombocytopenia) was initiated. Cultivation of pus revealed Streptococcus constellatus, Aggregatibacter aphrophilus and Fusobacterium spp. Within the first two weeks of treatment progession of the abscess was noted, therefore a second craniotomy with debridement was performed. An elective CT-angio scan revealed several arteriovenous malformations in the caudal segments of both lungs which were embolized without complications. Only retrospectively, cutaneous teleangiectasias were recognized. At present, the patient and her direct relatives are submitted to genetical screening for Osler's disease. In patients with brain abscesses of unknown origin and with a history of repeated epistaxis and/or gastrointestinal bleeding, Osler's disease (hereditary hemorrhagic telangiectasia) should be considered and pulmonary arteriovenous malformations excluded. Physicians should search for cutaneous or mucous teleangiectasias. Family screening and long-term follow-up according to international guidelines is recommended.

Real-time monitoring of the adherence of Streptococcus anginosus group bacteria to extracellular matrix decorin and biglycan proteoglycans in biofilm formation

Members of the Streptococcus anginosus group (SAGs) are significant pathogens. However, their pathogenic mechanisms are incompletely understood. This study investigates the adherence of SAGs to the matrix proteoglycans decorin and biglycan of soft gingival and alveolar bone. Recombinant chondroitin 4-sulphate(C4S)-conjugated decorin and biglycan were synthesised using mammalian expression systems. C4S-conjugated decorin/biglycan and dermatan sulphate (DS) decorin/biglycan were isolated from ovine alveolar bone and gingival connective tissue, respectively. Using surface plasmon resonance, adherence of the SAGs S. anginosus, Streptococcus constellatus and Streptococcus intermedius to immobilised proteoglycan was assessed as a function of real-time biofilm formation. All isolates adhered to gingival proteoglycan, 59% percent of isolates adhered to alveolar proteoglycans, 70% to recombinant decorin and 76% to recombinant biglycan. Higher adherence was generally noted for S. constellatus and S. intermedius isolates. No differences in adherence were noted between commensal and pathogenic strains to decorin or biglycan. DS demonstrated greater adherence compared to C4S. Removal of the glycosaminoglycan chains with chondroitinase ABC resulted in no or minimal adherence for all isolates. These results suggest that SAGs bind to the extracellular matrix proteoglycans decorin and biglycan, with interaction mediated by the conjugated glycosaminoglycan chain.

EComment. Mitral and aortic valve endocarditis caused by Streptococcus constellatus

Concistre and colleagues reported their experience with the treatment of mitral and aortic valve infective endocarditis (IE) caused by Streptococcus constellatus [1]. I think there are some points that should be discussed. Nowadays, Staphylococci and Streptococci are the most common causative microorganisms for native valve IE. In contrast to Staphylococci, Streptococci are rarely resistant to penicillin G, which is recommended by modern guidelines for treatment of streptococcal IE in combination with gentamicin [2]. Other approved options for such cases are third generation cephalosporins – ceftriaxone, again with gentamicin. This regimen may be preferable due to a larger spectrum of activity, covering penicillin-resistant cocci. Furthermore, it is much more convenient for patients and personnel (injection of ceftriaxone once daily compared to six doses of penicillin G per day). The described patient stayed for a long time in the department of infective disease. Unfortunately, all periods of disease before admission to the cardiac surgery unit is like a “black box”: there is no information concerning predisposing factors, concomitant pathology, diagnostics and treatment provided etc. These data are essential in understanding the logic behind the initial antibiotic choice. Nevertheless with regards to the above-mentioned guidelines, in cases of native valve IE with unknown flora, initial antibiotics must cover most common pathogens, such as Staphylococci, Streptococci and Enterococci [2]. In light of this, the penicillin G-gentamicin combination seemed to be insufficient, especially in a patient who had been transferred from another ward and had previously received antibiotics. In our practice, we tend to start with a more reliable ceftriaxon + vancomycin regimen for empirical perioperative treatment of IE with unidentified etiology for such cases. After receiving microbiological data, including blood and tissue cultures, initial antibiotics regimen can be adjusted, if necessary. There is no doubt that the published case report is interesting owing to the rarity of S. constellatus as an etiological factor of IE. During our more than 10 years of surveillance at the Bakoulev Scientific Center for Cardiovascular Surgery (Moscow, Russia), where more than 4000 operations with cardiopulmonary bypass are performed annually, we have had only 5 consecutive blood cultures with S. constellatus (all in paediatric patients with non-IE pathology; all strains were susceptible to penicillin). There were no cases of S. constellatus isolation from intraoperatively resected valvular tissues in patients with IE. Returning back the present case, I suppose that if adequate anti-bacterial therapy had been started at an early stage, complications and subsequent requirement of surgery might have been avoided in this elderly patient.

Anaerobic oral flora in the North American Black bear (Ursus americanus) in eastern North Carolina

Microbial flora can provide insight into the ecology and natural history of wildlife in addition to improving understanding of health risks. This study examines the anaerobic oral flora of hunter killed black bears (Ursus americanus) in eastern North Carolina. Oral swabs from the buccal and lingual supragingival tooth surfaces of the first and second mandibular and maxillary molars of 22 black bears were inoculated onto Brucella Blood Agar plates supplemented with hemin and vitamin K after transport from the field using reduced oxoid nutrient broth. Sixteen anaerobic bacterial species, representing nine genera were identified using the RapID ANA II Micromethod Kit system and a number of organisms grown that could not be identified with the system. The most frequently identified anaerobes were Peptostreptococcus prevotii, Streptococcus constellatus, and Porphyromonas gingivalis. The diversity in the anaerobic oral flora of black bear in eastern North Carolina suggests the importance of including these organisms in basic health risk assessment protocols and suggests a potential tool for assessment of bear/habitat interactions.

Milleri group streptococcus—a stepchild in the viridans family

The purpose of this investigation was to provide a comprehensive review of the pathogenic role and spectrum of disease of milleri group streptococci, with special attention to bloodstream invasion and to possible differential roles among the three species. All consecutive isolates of milleri group streptococci from any anatomic source, during a 37-month period, in a tertiary care teaching hospital in Tel-Aviv, Israel, were thoroughly investigated. Identification to the species level was performed by an automated system.Streptococcus anginosus constituted 82% of the 245 patient-unique isolates from hospitalized patients. All nonurinary isolates were involved in pyogenic infections mostly originating from the gastrointestinal tract, with bacteremia in 28 cases. The 71 urinary isolates represented either urinary tract infection or nonsignificant bacteriuria. No specific association could be detected between species and the infection site, except for a higher relative representation of Streptococcus constellatus in bacteremia. Milleri group streptococci are common in clinical practice and play a different pathogenic role to other viridans streptococci. Due to their invariable association with pyogenic processes, their presence in blood warrants immediate focus identification. In addition, they have a previously unappreciated clinical niche concerning urinary tract infection. The identification of viridans streptococci to the species level is of paramount clinical significance.

Mitral and aortic valve endocarditis caused by a rare pathogen: Streptococcus constellatus

Streptococcus constellatus endocarditis is associated with systemic embolism and frequently with a poor prognosis. We describe the first case reported in the literature of infective endocarditis by penicillin-resistant S. constellatus causing both mitral and aortic valve regurgitation, treated successfully with double-valve replacement.

Subgingival microbiota in adult Down syndrome periodontitis

The subgingival microbiota in Down syndrome and non-Down syndrome adults receiving periodic dental care was examined for 40 bacterial species using checkerboard DNA-DNA hybridization and the results were related to clinical periodontal attachment loss. A total of 44 Down syndrome, 66 non-Down syndrome mentally retarded and 83 mentally normal adults were clinically evaluated. This involved, for each subject, the removal of subgingival specimens from three interproximal sites on different teeth; all subgingival samples per subject were then pooled and assessed for the presence and levels of 40 bacterial species using species-specific whole-genomic DNA probes and checkerboard DNA-DNA hybridization. Significant group differences in species proportions averaged across subjects were evaluated using the Kruskal-Wallis test, and associations between subgingival species and mean subject attachment loss within Down syndrome and non-Down syndrome subject groups were quantified using Pearson correlation and multiple linear regression analysis. Down syndrome subjects exhibited greater attachment loss than non-Down syndrome subjects (p=0.05). Most microbial species were present in Down syndrome subjects at levels similar to non-Down syndrome subjects, except for higher proportions of Selenomonas noxia, Propionibacterium acnes, Streptococcus gordonii, Streptococcus mitis and Streptococcus oralis in Down syndrome subjects compared with non-Down syndrome study subjects, higher proportions of Treponema socranskii in Down syndrome subjects compared with non-Down syndrome mentally retarded subjects, and higher proportions of Streptococcus constellatus in Down syndrome subjects compared with mentally normal subjects. Down syndrome adults classified with periodontitis revealed higher subgingival levels of T. socranskii than Down syndrome subjects with no periodontitis (p=0.02). Higher subgingival proportions of S. constellatus, Fusobacterium nucleatum ssp. nucleatum, S. noxia and Prevotella nigrescens showed significant positive correlations (r=0.35-0.42) and higher proportions of Actinomyces naeslundii II and Actinomyces odontolyticus showed negative correlations (r=-0.36 to -0.40), with increasing mean subject attachment loss in Down syndrome adults. Individuals with Down syndrome show higher levels of some subgingival bacterial species and specific associations between certain subgingival bacterial species and loss of periodontal attachment. These findings are consistent with the notion that certain subgingival bacteria may contribute to the increased level of periodontal disease seen in Down syndrome individuals and raise the question as to the reason for increased colonization in Down syndrome.

Empiema causado por Streptococcus constellatus

We presented a case of patient with bipolar disorder that he was admitted in the respiratory unit of our hospital by empyema produced by Streptococcus constellatus (S. constellatus).S. constellatus can produce lung infections, specially patients with airway manipulation. The response to treatment with penicillin usually are good.

Biofilm-Forming Capacity on Clinically Isolated Streptococcus constellatus from an Odontogenic Subperiosteal Abscess Lesion

S. Treptococcus constellatus, a member of the S. Treptococcus anginosus Group (SAG), and known as part of indigenous oral microbiota, has been described to cause abscesses in various regions of the body, despite this organism appears to be innocuous, in general at its habitat. In this communication, we report a biofilm-forming capacity of a facultative anaerobic gram-positive coccus isolated as a dominant bacterium in an odontogenic subperiosteal abscess lesiony. The clinical isolate designated as strain H39 formed dense meshwork structures around the cells that are typical for biofilm forming bacteria, and produced viscous materials in its spent culture media. The 16S rRNA gene sequence of strain H39 was 99% homologous to that of S. Treptococcus constellatus ATCC 27823, a type strain for S. Treptococcus constellatus. Phylogenetic analysis using data sets of recN, groEL, tuf and 16S rRNA genes showed a sister relationship between strain H39 and S. Treptococcus constellatus ATCC 27823. Dense meshwork-like structures found on strain H39 were observed on S. Treptococcus constellatus ATCC 27823, but not on S. intermedius ATCC 27335 and S. anginosus ATCC 33397. Biofilm assay using 96-wells polystyrene microtiter plates revealed that S. Treptococcus constellatus strains H39 and ATCC 27823 can form dense biofilm on abiotic materials consistently. S. intermedius ATCC 27335 was able to form biofilm on microtiter plates at a lesser extent to those of S. Treptococcus constellatus strains. S. anginosus ATCC 33397 did not form biofilm on an abitotic material. As conclusions, dense meshwork structures around the cells of S. Treptococcus constellatus, and the capacity of S. Treptococcus constellatus and S. intermedius to form biofilm on abiotic materials as observed in this study might be related to the pathogenicity of these two organism and the tropism of organisms in SAG. As recently suggested, phylogenetic analysis could be a powerful tool for differentiating and identifying clinical isolates belong to SAG.

Molecular detection of in-vivo microbial contamination of metallic orthodontic brackets by checkerboard DNA-DNA hybridization

Knowing the microbiota that colonizes orthodontic appliances is important for planning strategies and implementing specific preventive measures during treatment. The purpose of this clinical trial was to evaluate invivo the contamination of metallic orthodontic brackets with 40 DNA probes for different bacterial species by using the checkerboard DNA-DNA hybridization (CDDH) technique. Eighteen patients, 11 to 29 years of age having fixed orthodontic treatment, were enrolled in the study. Each subject had 2 new metallic brackets bonded to different premolars in a randomized manner. After 30 days, the brackets were removed and processed for analysis by CDDH. Data on bacterial contamination were analyzed descriptively and with the Kruskal-Wallis and Dunn post tests (α= 0.05). Forty microbial species (cariogenic microorganisms, bacteria of the purple, yellow, green, orange complexes, "red complex+Treponema socranskii," and the cluster of Actinomyces) were assessed. Most bacterial species were present in all subjects, except for Streptococcus constellatus, Campylobacter rectus, Tannerella forsythia, T socranskii, and Lactobacillus acidophillus (94.4%), Propionibacterium acnes I and Eubacterium nodatum (88.9%), and Treponema denticola (77.8%). Among the cariogenic microorganisms, Streptococcus mutans and Streptococcus sobrinus were found in larger numbers than L acidophillus and Lactobacillus casei (P<0.001). The periodontal pathogens of the orange complex were detected in larger numbers than those of the "red complex+T socranskii" (P<0.0001). Among the bacteria not associated with specific pathologies, Veillonella parvula (purple complex) was the most frequently detected strain (P<0.0001). The numbers of yellow and green complex bacteria and the cluster of Actinomyces were similar (P>0.05). Metallic brackets in use for 1 month were multi-colonized by several bacterial species, including cariogenic microorganisms and periodontal pathogens, reinforcing the need for meticulous oral hygiene and additional preventive measures to maintain oral health in orthodontic patients.

Extracellular deoxyribonuclease production by periodontal bacteria

Whilst certain bacteria have long been known to secrete extracellular deoxyribonuclease (DNase), the purpose in microbial physiology was unclear. Recently, however, this enzyme has been demonstrated to confer enhanced virulence, enabling bacteria to evade the host's immune defence of extruded DNA/chromatin filaments, termed neutrophil extracellular traps (NETs). As NETs have recently been identified in infected periodontal tissue, the aim of this study was to screen periodontal bacteria for extracellular DNase activity. To determine whether DNase activity was membrane bound or secreted, 34 periodontal bacteria were cultured in broth and on agar plates. Pelleted bacteria and supernatants from broth cultures were analysed for their ability to degrade DNA, with relative activity levels determined using an agarose gel electrophoresis assay. Following culture on DNA-supplemented agar, expression was determined by the presence of a zone of hydrolysis and DNase activity related to colony size. Twenty-seven bacteria, including red and orange complex members Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Parvimonas micra, Prevotella intermedia, Streptococcus constellatus, Campylobacter rectus and Prevotella nigrescens, were observed to express extracellular DNase activity. Differences in DNase activity were noted, however, when bacteria were assayed in different culture states. Analysis of the activity of secreted DNase from bacterial broth cultures confirmed their ability to degrade NETs. The present study demonstrates, for the first time, that DNase activity is a relatively common property of bacteria associated with advanced periodontal disease. Further work is required to determine the importance of this bacterial DNase activity in the pathogenesis of periodontitis.

Biliary Actinomycosis Mimicking a Klatskin Tumor

A 59-year-old White woman presented with painless jaundice, pruritus, and 10-lb weight loss over a month to an outside facility. She did not have any fever. There was no past history of pancreatitis, abdominal surgery, or trauma. She had no history of smoking. Her labs were: total bilirubin 11.0 mg/dL, direct bilirubin 10.2 mg/dL, alkaline phosphatase (ALP) 655 U/L, aspartate aminotransferase (AST) 92 U/L, and alanine aminotransferase (ALT) 96 U/L. Magnetic resonance imaging showed a 4.5-cm mass at the porta hepatis with compression of the common bile duct and portal lymphadenopathy. CA 19-9 was elevated at 96 U/ml. She underwent a placement of two external biliary drains and had resolution of the jaundice. She was presumed to have Klatskin tumor, based on her clinical and radiological presentation, and the mass was unresectable given its proximity to the portal vein and hepatic artery. She was referred to our center for medical management of cholangiocarcinoma. Patients initially choose to be palliative and refused biopsy considering the high mortality of the tumor. She presented a few days later with abdominal pain and agreed for a biopsy. A few days after a computed tomography (CT)-guided biopsy of the mass, she developed fever, chills, hematemesis, and abdominal pain. On examination, she had a temperature of 99.6°F, blood pressure of 105/60 mmHg, pulse of 105/min, and respiration of 20/min. Her lungs were clear to auscultation. She had tenderness in the right upper quadrant of the abdomen. A repeat CT scan showed a 4.7-cm porta hepatis mass with encasement of the hepatic artery and with loss of fat planes between the mass and the gall bladder and duodenum (Fig. 1). A 1.7-cm gall stone was visualized. A 1-cm gastrohepatic lymph node was seen along with scattered lymph nodes measuring up to 1 cm in the retrocaval, aortocaval, and periaortic regions. Two biliary stents were in place. Upper gastrointestinal endoscopy showed fresh blood oozing from the ampulla of Vater, which was felt to be due to her mass. Digital subtraction angiography of the celiac trunk and superior mesenteric artery showed an 8-mm pseudoaneurysm of the third segmental branch of the left hepatic artery (Fig. 2). The bleeding was successfully stopped with coil and gel foam embolization. The pathology of the bile duct mass was negative for malignancy but showed acute and chronic inflammation and granulomas with gram-positive filamentous bacteria consistent with actinomycetes species (Fig. 3). Cultures grew Streptococcus constellatus, Prevotella intermedia, and Prevotella oris. The patient was started on IV penicillin, oral metronidazole and levaquin while in the hospital and made a slow recovery. M. Bansal (*) :A. Agarwal Department of Internal Medicine, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA e-mail: mbansal@uams.edu

Chemical composition, antimicrobial potential against cariogenic bacteria and cytotoxic activity of Tunisian Nigella sativa essential oil and thymoquinone

We investigate in this work the chemical composition by GC–EIMS, the antibacterial and the cytotoxic activities of Tunisian Nigella sativa essential oil and its bioactive compound, thymoquinone, were tested against various clinical cariogenic bacteria (n=30). Eighty-four compounds were identified in the essential oil. The major one was p-cymene (49.48%) whereas thymoquinone represented only 0.79%. The essential oil (2.43mg/disc) containing only 3.35μg of thymoquinone showed pronounced dose dependant antibacterial activity against Streptococcus mitis, Streptococcus mutans, Streptococcus constellatus and Gemella haemolysans (15.5±0.707mm). However, pure thymoquinone compound (150μg/disk) was active against all the studied strains especially S. mutans and S. mitis (24.5±0.71 and 22±1.41mm inhibition zones, respectively).Their MIC values are representatives of a good effect. So, the essential oil strongest activity was seen against S. mitis, S. mutans, S. constellatus and G. haemolysans (MIC 2.13mg/ml). However, thymoquinone was active against all the studied strains. The most important antibacterial activity was seen against S. constellatus (MIC 4μg/ml). The growth inhibition effects of thymoquinone on human epithelial cell lines (Hep-2) were significantly stronger than the essential oil. The IC50 of thymoquinone and essential oil were 19.25±1.6 and 55.2±2.1μg/ml, respectively.Our results demonstrate an important anticariogenic activity of the Tunisian N. sativa essential oil and thymoquinone. These effects further validate the traditional use of N. sativa in the folk medicine against various bacterial infections.

Absceso pélvico y tubo-ovárico en mujer portadora de DIU hace 16 años

We present a case of acute abdomen caused by rupture of a tubo-ovarian abscess in a 38-year-old woman who had been using an intrauterine device for 16 years. The diagnosis was made during surgery, since the intervention was performed for suspected acute appendicitis. The intervention revealed a right tubo-ovarian abscess with pelvic abscess. Culture of pelvic pus was positive for Streptococcus constellatus. The patient was treated by surgery and combined antibiotic therapy. Diagnosis was confirmed by histopathological examination.

Spiramycin resistance in human periodontitis microbiota

Purpose The occurrence of in vitro resistance to therapeutic concentrations of spiramycin, amoxicillin, and metronidazole was determined for putative periodontal pathogens isolated in the United States. Materials and methods Subgingival plaque specimens from 37 consecutive adults with untreated severe periodontitis were anaerobically cultured, and isolated putative periodontal pathogens were identified to a species level. In vitro resistance to spiramycin at 4 μg/ml, amoxicillin at 8 μg/ml, and/or metronidazole at 16 μg/ml was noted when putative periodontal pathogen growth was noted on the respective antibiotic-supplemented primary culture plates. Results A total of 18 (48.7%) subjects yielded antibiotic-resistant putative periodontal pathogens with spiramycin at 4 μg/ml in drug-supplemented primary isolation plates, as compared to 23 (62.2%) subjects with amoxicillin at 8 μg/ml, and 10 (27.0%) subjects with metronidazole at 16 μg/ml. Spiramycin in vitro resistance occurred among species of Fusobacterium nucleatum (44.4% of organism-positive subjects), Prevotella intermedia/nigrescens (11.1%), Parvimonas micra (10.8%), Streptococcus constellatus (10%), Streptococcus intermedius (10%), Porphyromonas gingivalis (6.7%), and Tannerella forsythia (5.3%). Amoxicillin in vitro resistance was found in P. intermedia/nigrescens (55.5%), T. forsythia (15.8%), S. constellatus (10%), F. nucleatum (5.6%), and P. micra (2.7%). Only S. constellatus (70%) and S. intermedius (40%) exhibited in vitro resistance to metronidazole. When subject-based resistance data for spiramycin and metronidazole were jointly considered, all isolated putative periodontal pathogens were inhibited in vitro by one or the other of the antibiotic concentrations, except for one strain each of S. constellatus and S. intermedius from one study subject. Similarly, either amoxicillin or metronidazole at the drug concentrations tested inhibited in vitro all recovered putative periodontal pathogens, except S. constellatus in one subject. Conclusions In vitro spiramycin resistance among putative periodontal pathogens of United States origin occurred in approximately one-half of severe periodontitis patients evaluated, particularly among subgingival F. nucleatum species. In vitro resistance patterns also suggest that therapeutic concentrations of spiramycin plus metronidazole may have potential antimicrobial efficacy in non- Aggregatibacter actinomycetemcomitans-associated periodontitis similar to amoxicillin plus metronidazole, which may be beneficial, where spiramycin is clinically available, for patients hypersensitive to amoxicillin or other beta-lactam antibiotics.

Antibacterial effects of Oradex, Gengigel and Salviathymol-n mouthwash on dental biofilm bacteria

Three mouthwashes Gengigel, Oradex and Salviathymol N, were tested using experimental microorganisms included Fusobacterium nucleatum, Streptococcus mitis, Streptococcus constellatus, Eikenella corrodens and dental plaque. Staphylococcus aureus and Escherichia coli were used as internal controls. Antibacterial activity was done by diffusion test. Minimum inhibitory concentration test and assessment of bacterial morphology was carried out using scanning electron microscopy (SEM). Results showed that Oradex had a higher antibacterial effect, followed by Salviathymol N; Gengigel mouthwash have weak antibacterial effects against tested microorganisms and dental plaque. SEM observations demonstrated that chlorhexidine exhibited obvious changes in that most of the bacteria loss their original shape and became irregular. The cell also shrunk, became reduced in size. Salviathymol N showed some significant changes while Gengigel failed to exhibited changes on the bacterial morphology of the tested microorganisms. In conclusion Oradex and Salviathymol N can be used as antibacterial mouthwash for chemical plaque control. Gengigel demonstrated weak antibacterial effects which could not be recommended as anti-dental plaque agent.

Linezolid Therapy of Brain Abscess

To the Editors: Brain abscess is a serious and uncommon intracerebral infection with limited therapeutic options in children.1,2 When no positive cultures are obtained, empiric treatment should be initiated with a broad-spectrum antimicrobial therapy.1,2 We studied the medical records of 7 children (4 males and 3 females) who had been diagnosed with brain abscess at the Bambino Gesù Children Hospital, Rome from 2004 to 2009. Microbiologic findings were positive in only 2 cases (Streptococcus constellatus in one patient and Streptococcus intermedia in another). On admission all patients promptly received intravenous antibiotic therapy. In all but 1 patient, there was no improvement. For this reason, the initial therapy was discontinued after an average of 11 days. We administered linezolid, either alone or associated with other antimicrobial agents. In one case, we decided to stop first line therapy and to start linezolid because of the availability of oral formulation. The dosage of linezolid was 30 mg/kg/daily given intravenously for median of 6 weeks (range, 27–70 days). The other patient received oral linezolid in a dosage of 1200 mg/daily. Linezolid therapy was associated with a progressive improvement in both the clinical condition and radiologic imaging. Conservative medical treatment of the abscess was sufficient for 3 patients. In Table, Supplemental Digital Content 1, https://links.lww.com/INF/A571, therapy schedule is summarized for each patient. Some patients were discharged with oral antibiotic therapy after a main period of 50 days hospitalization. After an average period of 18 months (range, 6–51 months), all patients were in good clinical condition, except 1 who experienced seizures at home. We chose linezolid therapy because of its favorable pharmacodynamic properties, such as the possibility of both intravenous and oral administration.3–5 This is particularly important for prolonged antibiotic treatment, to reduce the number of complications due to venous catheterization and the period of hospitalization. We had just 1 case of neutropenia, which disappeared 1 week after therapy discontinuation. Andrzej Krzysztofiak, MD Elena Bozzola, MD Laura Lancella, MD Anna Quondamcarlo, MD Francesco Gesualdo, MD Alberto G. Ugazio, MD Infectious Disease Unit Pediatric Department Bambino Gesù Children Hospital Rome, Italy

The viridans group streptococci

The viridans group streptococci (VGS) are an extremely diverse range of organisms within the genus Streptococcus, which are characterized by a greening of the blood in blood agar, on which they are normally grown. Oral streptococci largely comprise members of the VGS, which currently include 20 species, which are commensal inhabitants of the oropharyngeal cavity, and the gastrointestinal and genital tracts of mammals. On the basis of 16S rRNA sequence homology, these bacteria are categorised into four groups: the salivarius rRNA homology group, including Streptococcus thermophilus, Streptococcus vestibularis and Streptococcus salivarius; the mitis group, including Streptococcus cristatus, Streptococcus gordonii, Streptococcus oralis, Streptococcus mitis, Streptococcus pneumoniae, Streptococcus sanguinis and Streptococcus parasanguinis; the anginosus group, including Streptococcus anginosus, Streptococcus constellatus and Streptococcus intermedius; and the mutans group, including Streptococcus mutans, Streptococcus criceti, Streptococcus downei, Streptococcus ferus, Streptococcus macacae, Streptococcus ratti and Streptococcus sobrinus. This review aims at comparing conventional and molecular detection methods and the emergence of antibiotic resistance within the VGS.