Fusobacterium/Peptostreptococcus - A Case Report of Community- Acquired Empyema Resulting in Surgical Decortication with Prolonged Antibiotic Therapy: A Case Series and Review of the Literature.

Background: Infections caused by anaerobic bacteria occur frequently and can be serious and life-threatening. Anaerobes are a rare cause of community-acquired pneumonia with Streptococcus pneumonia and respiratory viruses being the most frequently detected pathogens. We, herein, report a case of Fusobacterium/Peptostreptococcus parapneumonic effusion with empyema in a patient without risk factors for aspiration pneumonia. This case presents an opportunity to discuss an unusual case of community-acquired empyema secondary to anaerobic infection in a patient without the common risk factors for aspiration.

Case Presentation: A 59-year-old male patient without significant past medical history apart from a twenty-five-year history of smoking presented due to left flank pain and shortness of breath. Findings of a complicated parapneumonic effusion were found on imaging, resulting in surgical decortication and prolonged antibiotic therapy.

Discussion: Parapneumonic effusions and empyema are relatively common complications of pneumonia. It is important to note that the incidence of anaerobic empyema has been on the rise due to more modern culturing techniques.

Conclusion: This case highlights an unusual presentation of community-acquired empyema secondary to anaerobes without any risk factors for aspiration pneumonia. Therefore, clinicians should consider the possibility of anaerobic coverage in the treatment of community-acquired empyema in the appropriate setting.

Parvimonas micra, Peptostreptococcus stomatis, Fusobacterium nucleatum and Akkermansia muciniphila as a four-bacteria biomarker panel of colorectal cancer.

Dysbiosis of the gut microbiome has been associated with the pathogenesis of colorectal cancer (CRC). We profiled the microbiome of gut mucosal tissues from 18 CRC patients and 18 non-CRC controls of the UKM Medical Centre (UKMMC), Kuala Lumpur, Malaysia. The results were then validated using a species-specific quantitative PCR in 40 CRC and 20 non-CRC tissues samples from the UMBI-UKMMC Biobank. Parvimonas micra, Fusobacterium nucleatum, Peptostreptococcus stomatis and Akkermansia muciniphila were found to be over-represented in our CRC patients compared to non-CRC controls. These four bacteria markers distinguished CRC from controls (AUROC = 0.925) in our validation cohort. We identified bacteria species significantly associated (cut-off value of > 5 fold abundance) with various CRC demographics such as ethnicity, gender and CRC staging; however, due to small sample size of the discovery cohort, these results could not be further verified in our validation cohort. In summary, Parvimonas micra, Fusobacterium nucleatum, Peptostreptococcus stomatis and Akkermansia muciniphila were enriched in our local CRC patients. Nevertheless, the roles of these bacteria in CRC initiation and progression remains to be investigated.

A Retrospective Chart Review of Inflamed Epidermal Inclusion Cysts.

BACKGROUND: Epidermal inclusion cysts (EIC) are one of the most common forms of cysts found on and/or underneath the skin. Inflamed EICs typically show signs and symptoms such as pain and erythema, mimicking cutaneous abscess. However, prior studies have demonstrated at least 20% of lesions are culture negative. OBJECTIVE: To determine the rate of culture positivity in mild inflamed epidermal inclusion cysts, in particular to identify whether empiric antibiotics are warranted. METHODS: In a retrospective chart review 76 cases of inflamed EIC that were mild (lacking systemic symptoms) were analyzed who presented to the department of dermatology at Mount Sinai between 2016–2019. RESULTS: Of cultures taken from inflamed cysts, 47% resulted in no bacterial growth or growth of normal flora, 38.4% resulted in growth of aerobic bacteria with methicillin-resistant Staphylococcus aureus (8%), Staphylococcus lugdunensis (5%), and methicillin-sensitive Staphylococcus aureus (13%) predominating, and 9.3% resulting in growth of anaerobic bacteria with Finegoldia magna, Peptostreptococcus, and Cutibacterium acnes presenting. Review of prescribed treatment regimens often involved antibiotic medication, despite a high prevalence of negative culture. CONCLUSIONS: Almost half of cases of mild inflamed EIC (lacking systemic symptoms) cultured will not grow pathogenic bacteria, therefore incision and drainage with culture and appropriate therapy is a viable therapeutic option in uncomplicated inflamed EIC lesions. In this way, over prescription of antibiotics can be minimized. J Drugs Dermatol. 2021;20(2):199-202. doi:10.36849/JDD.5014.

Network Analysis of Gut Microbiome and Metabolome to Discover Microbiota-Linked Biomarkers in Patients Affected by Non-Small Cell Lung Cancer.

Several studies in recent times have linked gut microbiome (GM) diversity to the pathogenesis of cancer and its role in disease progression through immune response, inflammation and metabolism modulation. This study focused on the use of network analysis and weighted gene co-expression network analysis (WGCNA) to identify the biological interaction between the gut ecosystem and its metabolites that could impact the immunotherapy response in non-small cell lung cancer (NSCLC) patients undergoing second-line treatment with anti-PD1. Metabolomic data were merged with operational taxonomic units (OTUs) from 16S RNA-targeted metagenomics and classified by chemometric models. The traits considered for the analyses were: (i) condition: disease or control (CTRLs), and (ii) treatment: responder (R) or non-responder (NR). Network analysis indicated that indole and its derivatives, aldehydes and alcohols could play a signaling role in GM functionality. WGCNA generated, instead, strong correlations between short-chain fatty acids (SCFAs) and a healthy GM. Furthermore, commensal bacteria such as Akkermansia muciniphila, Rikenellaceae, Bacteroides, Peptostreptococcaceae, Mogibacteriaceae and Clostridiaceae were found to be more abundant in CTRLs than in NSCLC patients. Our preliminary study demonstrates that the discovery of microbiota-linked biomarkers could provide an indication on the road towards personalized management of NSCLC patients.

Enterobacter cloacae Periprosthetic Joint Infection After Bariatric Surgical Anastomotic Leak.

Four weeks after a bilateral total knee arthroplasty (TKA), an immunocompetent, 61-year-old, Caucasian man presented with a periprosthetic joint infection (PJI) of the left knee by Enterobacter cloacae (an enteric bacteria). The most likely source of his infection was due to an anastomotic leak after a bariatric surgery done 6 months before TKA. There is a growing focus on stratifying the risk of PJI after TKA. Hematogenous seeding of enteric bacteria leading to PJI is an unexplored risk that will become more prevalent as bariatric procedures before TKA continue to increase in frequency. We present a patient who demonstrates this PJI risk with a rare microbe (E cloacae).

Septic arthritis of knee joint due to Parvimonas micra.

Parvimonas species are anaerobic, Gram-positive cocci that are a constituent of normal oral and gastrointestinal flora. We present a case of right knee joint septic arthritis due to Parvimonas micra in an immunocompromised patient. A 61-year-old male renal and pancreatic transplant recipient on immunosuppressive therapy was admitted to our hospital due to intense pain, joint swelling and inability to move his right knee over the past 9 months. After synovial fluid was drawn, cultures were positive for P. micra, an anaerobic pathogen that is part of the flora of the oral cavity. We report a rare causative pathogen for septic arthritis in an immunocompromised patient.

Spondylodiscitis due to Parvimonas micra diagnosed by the melting temperature mapping method: a case report.

BACKGROUND: It has been suggested that more than 100 bacterial species can be identified using only seven universal bacterial primer sets in the melting temperature (Tm) mapping method and that these findings can be obtained within 3 h of sterile site collection. CASE PRESENTATION: A 67-year-old Japanese man with type 2 diabetes visited our hospital complaining of progressive lower back pain for 2 months. The patient was suspected to have spondylodiscitis on magnetic resonance imaging of the spine. Blood culture and transcutaneous vertebral biopsy were subsequently performed. Using the Tm mapping method, Parvimonas micra was detected from a transcutaneous vertebral biopsy specimen in 3 h. Gram-positive cocci were also detected by Gram staining and P. micra was identified directly from the anaerobic blood culture by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Four days after admission, the biopsy specimen culture isolate was identified as P. micra. CONCLUSIONS: The Tm mapping method may be useful for the diagnosis of bacterial infections where diagnosis is challenging because of the difficulty of culturing.

Osteomyelitis of the jaw (with pathological fracture) following extraction of an impacted wisdom tooth. A case report.

Osteomyelitis is an infection and inflammation associated with the bone structures: bone marrow, cortical bone, periosteum, blood vessels and nerves. Although it does not have a frequent presentation, it can sometimes lead to complications such as pathological fractures or even septicemia. We present a clinical case study, to assess the relationship between osteomyelitis of the jaw and pathological fractures, after the extraction of an impacted wisdom tooth. This case highlights a rare complication following the surgical removal of mandibular third molar; a slow evolution of the pathology following an extraction should lead to close monitoring of the patient both clinically and radiographically, albeit osteomyelitis is a rare complication, it should be included as one of the differential diagnosis of persistent post-extraction pain.

Peptostreptococcus anaerobius Induces Intracellular Cholesterol Biosynthesis in Colon Cells to Induce Proliferation and Causes Dysplasia in Mice.

BACKGROUND & AIMS: Stool samples from patients with colorectal cancer (CRC) have a higher abundance of Peptostreptococcus anaerobius than stool from individuals without CRC, based on metagenome sequencing. We investigated whether P anaerobius contributes to colon tumor formation in mice and its possible mechanisms of carcinogenesis. METHODS: We performed quantitative polymerase chain reaction analyses to measure P anaerobius in 112 stool samples and 255 colon biopsies from patients with CRC or advanced adenoma and from healthy individuals (controls) undergoing colonoscopy examination at hospitals in Hong Kong and Beijing. C57BL/6 mice were given broad-spectrum antibiotics, followed by a single dose of azoxymethane, to induce colon tumor formation. Three days later, mice were given P anaerobius or Esherichia coli MG1655 (control bacteria), via gavage, for 6 weeks. Some mice were also given the nicotinamide adenine dinucleotide phosphate oxidase inhibitor apocynin. Intestine tissues were collected and analyzed histologically. The colon epithelial cell line NCM460 and colon cancer cell lines HT-29 and Caco-2 were exposed to P anaerobius or control bacteria; cells were analyzed by immunoblot, proliferation, and bacterial attachment analyses and compared in gene expression profiling studies. Gene expression was knocked down in these cell lines with small interfering RNAs. RESULTS: P anaerobius was significantly enriched in stool samples from patients with CRC and in biopsies from patients with colorectal adenoma or CRC compared with controls. Mice depleted of bacteria and exposed to azoxymethane and P anaerobius had a higher incidence of intestinal dysplasia (63%) compared with mice not given the bacteria (8.3%; P < .01). P anaerobius mainly colonized the colon compared with the rest of the intestine. Colon cells exposed to P anaerobius had significantly higher levels of proliferation than control cells. We found genes that regulate cholesterol biosynthesis, Toll-like receptor (TLR) signaling, and AMP-activated protein kinase signaling to be significantly up-regulated in cells exposed to P anaerobius. Total cholesterol levels were significantly increased in colon cell lines exposed to P anaerobius via activation of sterol regulatory element-binding protein 2. P anaerobius interacted with TLR2 and TLR4 to increase intracellular levels of reactive oxidative species, which promoted cholesterol synthesis and cell proliferation. Depletion of reactive oxidative species by knockdown of TLR2 or TLR4, or incubation of cells with an antioxidant, prevented P anaerobius from inducing cholesterol biosynthesis and proliferation. CONCLUSIONS: Levels of P anaerobius are increased in human colon tumor tissues and adenomas compared with non-tumor tissues; this bacteria increases colon dysplasia in a mouse model of CRC. P anaerobius interacts with TLR2 and TLR4 on colon cells to increase levels of reactive oxidative species, which promotes cholesterol synthesis and cell proliferation.

Metagenomic analysis of faecal microbiome as a tool towards targeted non-invasive biomarkers for colorectal cancer.

OBJECTIVE: To evaluate the potential for diagnosing colorectal cancer (CRC) from faecal metagenomes. DESIGN: We performed metagenome-wide association studies on faecal samples from 74 patients with CRC and 54 controls from China, and validated the results in 16 patients and 24 controls from Denmark. We further validated the biomarkers in two published cohorts from France and Austria. Finally, we employed targeted quantitative PCR (qPCR) assays to evaluate diagnostic potential of selected biomarkers in an independent Chinese cohort of 47 patients and 109 controls. RESULTS: Besides confirming known associations of Fusobacterium nucleatum and Peptostreptococcus stomatis with CRC, we found significant associations with several species, including Parvimonas micra and Solobacterium moorei. We identified 20 microbial gene markers that differentiated CRC and control microbiomes, and validated 4 markers in the Danish cohort. In the French and Austrian cohorts, these four genes distinguished CRC metagenomes from controls with areas under the receiver-operating curve (AUC) of 0.72 and 0.77, respectively. qPCR measurements of two of these genes accurately classified patients with CRC in the independent Chinese cohort with AUC=0.84 and OR of 23. These genes were enriched in early-stage (I-II) patient microbiomes, highlighting the potential for using faecal metagenomic biomarkers for early diagnosis of CRC. CONCLUSIONS: We present the first metagenomic profiling study of CRC faecal microbiomes to discover and validate microbial biomarkers in ethnically different cohorts, and to independently validate selected biomarkers using an affordable clinically relevant technology. Our study thus takes a step further towards affordable non-invasive early diagnostic biomarkers for CRC from faecal samples.

Effect of smokeless tobacco products on human oral bacteria growth and viability.

To evaluate the toxicity of smokeless tobacco products (STPs) on oral bacteria, seven smokeless tobacco aqueous extracts (STAEs) from major brands of STPs and three tobacco-specific N-nitrosamines (TSNAs) were used in a growth and viability test against 38 oral bacterial species or subspecies. All seven STAEs showed concentration-dependent effects on the growth and viability of tested oral bacteria under anaerobic culture conditions, although there were strain-to-strain variations. In the presence of 1 mg/ml STAEs, the growth of 4 strains decreased over 0.32-2.14 log10 fold, while 14 strains demonstrated enhanced growth of 0.3-1.76 log10 fold, and the growth of 21 strains was not significantly affected. In the presence of 10 mg/ml STAEs, the growth of 17 strains was inhibited 0.3-2.11 log10 fold, 18 strains showed enhanced growth of 0.3-0.97 log10 fold, and 4 strains were not significantly affected. In the presence of 50 mg/ml STAEs, the growth of 32 strains was inhibited 0.3-2.96 log10 fold, 8 strains showed enhanced growth of 0.3-1.0 log10 fold, and 2 strains were not significantly affected. All seven STAEs could promote the growth of 4 bacterial strains, including Eubacterium nodatum, Peptostreptococcus micros, Streptococcus anginosus, and Streptococcus constellatus. Exposure to STAEs modulated the viability of some bacterial strains, with 21.1-66.5% decrease for 4 strains at 1 mg/ml, 20.3-85.7% decrease for 10 strains at 10 mg/ml, 20.0-93.3% decrease for 27 strains at 50 mg/ml, and no significant effect for 11 strains at up to 50 mg/ml. STAEs from snuffs inhibited more tested bacterial strains than those from snus indicating that the snuffs may be more toxic to the oral bacteria than snus. For TSNAs, cell growth and viability of 34 tested strains were not significantly affected at up to 100 µg/ml; while the growth of P. micros was enhanced 0.31-0.54 log10 fold; the growth of Veillonella parvula was repressed 0.33-0.36 log10 fold; and the cell viabilities of 2 strains decreased 56.6-69.9%. The results demonstrate that STAEs affected the growth of some types of oral bacteria, which may affect the healthy ecological balance of oral bacteria in humans. On the other hand, TSNAs did not significantly affect the growth of the oral bacteria.

Association of three putative periodontal pathogens with chronic periodontitis in Brazilian subjects

ABSTRACT Objective The aim of this study was to evaluate the association of Porphyromonas endodontalis, Filifactor alocis and Dialister pneumosintes with the occurrence of periodontitis. Material and Methods Thirty subjects with chronic periodontitis (ChP) and 10 with periodontal health (PH) were included in the study. Nine subgingival biofilm samples were collected as follows: i) PH group - from the mesial/buccal aspect of each tooth in two randomly chosen contralateral quadrants; ii) ChP group - from three sites in each of the following probing depth (PD) categories: shallow (≤3 mm), moderate (4-6 mm) and deep (≥7 mm). Checkerboard DNA-DNA hybridization was used to analyze the samples. Results We found the three species evaluated in a higher percentage of sites and at higher levels in the group with ChP than in the PH group (p<0.05, Mann-Whitney test). We also observed these differences when the samples from sites with PD≤4 mm or ≥5 mm of subjects with ChP were compared with those from subjects with PH (p<0.05, Mann-Whitney test). In addition, the prevalence and levels of D. pneumosintes, and especially of F. alocis were very low in healthy subjects (0.12x105 and 0.01x105, respectively). Conclusion F. alocis and D. pneumosintes might be associated with the etiology of ChP, and their role in the onset and progression of this infection should be further investigated. The role of P. endodontalis was less evident, since this species was found in relatively high levels and prevalence in the PH group.

Cervical intraepithelial neoplasia disease progression is associated with increased vaginal microbiome diversity.

Persistent infection with oncogenic Human Papillomavirus (HPV) is necessary for cervical carcinogenesis. Although evidence suggests that the vaginal microbiome plays a functional role in the persistence or regression of HPV infections, this has yet to be described in women with cervical intra-epithelial neoplasia (CIN). We hypothesised that increasing microbiome diversity is associated with increasing CIN severity. llumina MiSeq sequencing of 16S rRNA gene amplicons was used to characterise the vaginal microbiota of women with low-grade squamous intra-epithelial lesions (LSIL; n = 52), high-grade (HSIL; n = 92), invasive cervical cancer (ICC; n = 5) and healthy controls (n = 20). Hierarchical clustering analysis revealed an increased prevalence of microbiomes characterised by high-diversity and low levels of Lactobacillus spp. (community state type-CST IV) with increasing disease severity, irrespective of HPV status (Normal = 2/20,10%; LSIL = 11/52,21%; HSIL = 25/92,27%; ICC = 2/5,40%). Increasing disease severity was associated with decreasing relative abundance of Lactobacillus spp. The vaginal microbiome in HSIL was characterised by higher levels of Sneathia sanguinegens (P < 0.01), Anaerococcus tetradius (P < 0.05) and Peptostreptococcus anaerobius (P < 0.05) and lower levels of Lactobacillus jensenii (P < 0.01) compared to LSIL. Our results suggest advancing CIN disease severity is associated with increasing vaginal microbiota diversity and may be involved in regulating viral persistence and disease progression.

Use of metronidazole as part of an empirical antibiotic regimen after incision and drainage of infections of the odontogenic spaces.

The combination of amoxicillin/clavulanate and metronidazole is a widely-accepted empirical regimen for infections of the odontogenic spaces. Once adequate drainage has been established micro-organisms are less likely to grow and multiply, particularly anaerobes. This may obviate the need for anaerobic coverage after drainage in healthy hosts. We studied 60 patients in this randomised prospective study, the objective of which was to evaluate metronidazole as part of an empirical antibiotic regimen after drainage of infections of the odontogenic spaces. Samples of pus were sent for culture and testing for sensitivity. Amoxicillin/clavulanate and metronidazole were given to all patients. After incision and drainage the patients were randomly allocated to two groups. In the first group both antibiotics were continued, and in the second metronidazole was withdrawn. The groups were compared both clinically and microbiologically. There were no significant differences between the groups in the resolution of infection. Thirteen patients (n=6 in the 2-antimicrobial group, and n=7 in the amoxicillin/clavulanate group) showed no improvement during the 48 h postoperatively. Overall there was need to substitute another antibiotic for amoxicillin/clavulanate in only 6 cases. Six patients in the amoxicillin/clavulanate group required the addition of metronidazole after drainage. We conclude that in healthy subjects metronidazole is not necessary in the period after drainage, but its prescription should be based on assessment of clinical and laboratory markers of infection.

Macrophage cell activation with acute apical abscess contents determined by interleukin-1 Beta and tumor necrosis factor alpha production.

INTRODUCTION: This clinical study has investigated the antigenic activity of bacterial contents from exudates of acute apical abscesses (AAAs) and their paired root canal contents regarding the stimulation capacity by levels of interleukin (IL)-1 beta and tumor necrosis factor alpha (TNF-α) throughout the root canal treatment against macrophage cells. METHODS: Paired samples of infected root canals and exudates of AAAs were collected from 10 subjects. Endodontic contents were sampled before (root canal sample [RCS] 1) and after chemomechanical preparation (RCS2) and after 30 days of intracanal medication with calcium hydroxide + chlorhexidine gel (Ca[OH]2 + CHX gel) (RCS3). Polymerase chain reaction (16S rDNA) was used for detection of the target bacteria, whereas limulus amebocyte lysate was used to measure endotoxin levels. Raw 264.7 macrophages were stimulated with AAA exudates from endodontic contents sampled in different moments of root canal treatment. Enzyme-linked immunosorbent assays were used to measure the levels of TNF-α and IL-1 beta. RESULTS: Parvimonas micra, Porphyromonas endodontalis, Dialister pneumosintes, and Prevotella nigrescens were the most frequently detected species. Higher levels of endotoxins were found in samples from periapical exudates at RCS1 (P < .005). In fact, samples collected from periapical exudates showed a higher stimulation capacity at RCS1 (P < .05). A positive correlation was found between endotoxins from exudates with IL-1 beta (r = 0.97) and TNF-α (r = 0.88) production (P < .01). The significant reduction of endotoxins and bacterial species achieved by chemomechanical procedures (RCS2) resulted in a lower capacity of root canal contents to stimulate the cells compared with that at RCS1 (P < .05). The use of Ca(OH)2 + CHX gel as an intracanal medication (RCS3) improved the removal of endotoxins and bacteria from infected root canals (P < .05) whose contents induced a lower stimulation capacity against macrophages cells at RCS1, RCS2, and RCS3 (P < .05). CONCLUSIONS: AAA exudates showed higher levels of endotoxins and showed a greater capacity of macrophage stimulation than the paired root canal samples. Moreover, the use of intracanal medication improved the removal of bacteria and endotoxins from infected root canals, which may have resulted in the reduction of the inflammatory potential of the root canal content.

Signaling pathways activation by primary endodontic infectious contents and production of inflammatory mediators.

INTRODUCTION: This study investigated the bacterial community involved in primary endodontic diseases, evaluated its ability to activate the macrophage Toll-like receptor 4 receptor through p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling pathways, and determined the levels of endotoxins and interleukins (interleukin [IL]-6 and -10) produced by endodontic content-stimulated macrophages. METHODS: Samples were taken from 21 root canals by using sterile/apyrogenic paper points. Raw 264.7 macrophages were stimulated with root canal contents. Checkerboard DNA-DNA hybridization was used for bacterial analysis and the limulus amebocyte lysate assay for endotoxin measurement; p38 MAPK and NF-κB activation was determined by Western blot analysis. IL-6 and IL-10 were measured using the enzyme-linked immunosorbent assay. RESULTS: Bacteria and endotoxins were detected in 100% of the samples (21/21). The most frequently observed species were Parvimonas micra (16/21, 76%), Fusobacterium nucleatum ssp. nucleatum (15/21, 71%), and Porphyromonas endodontalis (14/21, 66%). Correlations were found between endotoxins and IL-6 and IL-10 (P < .05); p38 phosphorylation had a peak at 60 minutes, and NF-κB was quickly activated after 10 minutes of stimulation. CONCLUSIONS: It was concluded that the complex bacterial community was shown to be a potent activator of TLR-4 determined by the p38 MAPK and NF-κB signaling pathways, culminating in a high antigenicity against macrophages through the levels of IL-6 and IL-10, all significantly affected by endotoxin levels.

Subgingival periodontal pathogens associated with chronic periodontitis in Yemenis.

BACKGROUND: Subgingival microbial profile associated with periodontitis has been reported to significantly differ by geographical location. The purpose of this study was to assess the association between a panel of putative periodontal bacterial pathogens and chronic periodontitis among Yemenis. METHODS: Subgingival DNA samples were obtained from diseased and healthy sites of 20 non-smoking, moderate to severe chronic periodontitis subjects. Absolute counts (bacterial DNA copies per sample) and relative counts (% total bacteria) of seven periopathogenic species/genera representative of the red and orange complexes were determined using Taqman q-PCR assays. RESULTS: The q-PCR assays showed excellent linearity (R2 > 0.99) and a sensitivity of 100 copies/sample. The detection rate was 100% for all tested species/genera except for P. gingivalis and A. actinomycetemcomitans that were detected at 97.5% and 67.5%, respectively. The median log absolute counts were in the range of 2.41-6.53 copies per sample while median relative counts were in the range of 0.001-0.77%, both being highest for fusobacteria and lowest for A. actinomycetemcomitans. Significant interspecies correlations were observed. Adjusting for multiple comparisons (P≤0.0063), only T. forsythia, T. denticola and P. micra maintained significant association with periodontal destruction. The latter species, however, showed the strongest association and was found in higher proportions at the periodontitis sites across all subjects (3.39 median fold increase). No significant differences were observed for P. gingivalis. CONCLUSIONS: P. micra rather than P. gingivalis appears as a keystone pathogen in this Yemeni Sample. However, these findings need to be validated in a larger-scale study before they can be claimed to represent ethnic variations in pathogens' association with periodontitis.

Bacteriological evaluation of tonsillar microbial flora according to age and tonsillar size in recurrent tonsillitis.

Although numerous studies based on the bacteriology of the tonsil have been carried out, none of them analyzed the variation of tonsillar flora with respect to both age and tonsillar size. The purpose of this study was to isolate the facultative and obligate anaerobes both from the surface and the core of tonsils in recurrent tonsillitis as well as to analyze the variation of isolated bacterial strains according to age and tonsillar size. A prospective study was performed on 111 patients who underwent tonsillectomy. We analyzed the differences between the bacterial pathogens in recurrent tonsillitis and semi-growth estimates with regard to age and tonsillar grade. Among 111 cases, 604 bacterial strains of 21 different from the tonsil superficial and core were isolated. The most common facultative anaerobic species isolated from the surface and core were Coagulase-negative staphylococci, Alpha-hemolytic streptococci and Diphtheroid bacilli in all subgroups except patients below 8 years old. The most commonly obligate anaerobic species isolated from the core were Propionibacterium acnes, Prevotella melaninogenica and Peptostreptococcus anaerobius. We found no significant difference in the cultured bacteria with respect to age and tonsillar size. The study subgroups did not differ in the occurrence of semiquantitative growth estimates of 3-4+. Our study demonstrates that there is polymicrobial aerobic and anaerobic flora in tonsils with regardless of patient's age and tonsillar size. This polymicrobial spectrum of bacteria may contribute to recurrence and to the failure of conservative treatment of these cases and therefore leads to surgical therapy.