Specific infections as the etiology of destructive periodontal disease: a systematic review.

Destructive periodontal disease has been primarily defined and investigated as an infectious disease. The aim of this study was to systematically search for cohort studies where microbiological diagnoses were performed before the onset of destructive periodontal disease and where statistically significant associations were identified. A search was executed in PubMed. The results showed that three studies published after 2005 supported the infection hypothesis for one putative periodontal pathogen: Aggregatibacter actinomycetemcomitans. These three studies were conducted in predominantly non-Caucasian pediatric populations living in geographic areas with an elevated child-mortality rate. These studies did not obtain physical or laboratory markers of health, making it possible that A. actinomycetemcomitans was not a cause but a marker for poor environmental or systemic health. No cohort studies were identified supporting the infection hypothesis in adults, Caucasians or in a population residing in areas with child-mortality rates reflective of healthy population goals. While the possibility cannot be excluded that A. actinomycetemcomitans has an etiological role in certain specific pediatric populations, there are no cohort studies supporting an infectious etiology of destructive periodontal disease in adults.

Bacterial colonization patterns of periodontal pockets in different ages.

The aim of this study was to investigate subgingival bacterial composition of untreated Italian subjects with aggressive and chronic periodontitis. The total bacterial load, pathogenic bacteria belonging to "red" and "orange" complexes and Aggregatibacter actinomycetemcomitans were determined by Real-Time PCR in 1216 patients. Data were analysed by looking for relationships between bacteriological parameters, age and periodontal probing depth. The obtained results showed a significant higher number of red complex bacteria in older rather than in younger patients. The total number of bacteria and the presence of A. actinomycetemcomitans did not clearly associate with an age group.

Functional interferences in host inflammatory immune response by airway allergic inflammation restrain experimental periodontitis development in mice.

AIMS: periodontal disease (PD) and airway allergic inflammation (AL) present opposing inflammatory immunological features and clinically present an inverse correlation. However, the putative mechanisms underlying such opposite association are unknown. MATERIAL AND METHODS: Balb/C mice were submitted to the co-induction of experimental PD (induced by Actinobacillus actinomycetemcomitans oral inoculation) and AL [induced by sensitization with ovalbumin (OVA) and the subsequent OVA challenges], and evaluated regarding PD and AL severity, immune response [cytokine production at periodontal tissues, and T-helper transcription factors in submandibular lymph nodes (LNs)] and infection parameters. RESULTS: PD/AL co-induction decreased PD alveolar bone loss and periodontal inflammation while experimental AL parameters were unaltered. An active functional interference was verified, because independent OVA sensitization and challenge not modulate PD outcome. PD+AL group presented decreased tumour necrosis factor-α (TNF-α), interleukin (IL)-1ß, interferon-γ, IL-17A, receptor activator of nuclear factor κ-light-chain-enhancer of activated B cells ligand and matrix metalloproteinase (MMP)-13 levels in periodontal tissues, while IL-4 and IL-10 levels were unaltered by AL co-induction. AL co-induction also resulted in upregulated T-bet and related orphan receptor γ and downregulated GATA3 levels expression in submandibular LNs when compared with PD group. CONCLUSION: our results demonstrate that the interaction between experimental periodontitis and allergy involves functional immunological interferences, which restrains experimental periodontitis development by means of a skewed immune response.

Detection of the highly leucotoxic JP2 clone of Aggregatibacter actinomycetemcomitans in members of a Caucasian family living in Sweden.

BACKGROUND: carriers of the JP2 clone of Aggregatibacter actinomycetemcomitans exhibit an enhanced risk for developing aggressive periodontitis compared with individuals carrying non-JP2 clones. While the JP2 clone is almost exclusively detected among adolescents of African descent, reports on Caucasians colonized with the JP2 clone are remarkably few. OBJECTIVE: the aim of this paper is to report on the history of periodontal disease and microbiological findings in a Caucasian family. MATERIAL AND METHODS: a. actinomycetemcomitans and other periodontitis-associated bacterial species in subgingival plaque samples were quantified by conventional culture technique. Leucotoxin promoter typing, serotyping and further characterizations of A. actinomycetemcomitans isolates were performed by PCR. DNA sequencing of the pseudogene, hbpA was performed to determine the origin of the detected JP2 clones. Further, genetically ancestry testing of family members was carried out. RESULTS: the JP2 clone was detected in samples from two of the family members, a 33-year-old daughter and her 62-year-old mother. Relationship of their JP2 clones with JP2 clone strains from the Mediterranean area of Africa was indicated. Genotyping confirmed the Caucasian origin of all family members. CONCLUSIONS: Caucasian JP2 carriers exist and older subjects can carry the JP2 clone of A. actinomycetemcomitans.

Prevalence and distribution of Aggregatibacter actinomycetemcomitans serotypes and the JP2 clone in a Greek population.

AIM: to investigate the distribution of Aggregatibacter actinomycetemcomitans serotypes and the prevalence of the JP2 clone in subgingival samples of Greek subjects. MATERIALS AND METHODS: two hundred and twenty eight subjects participated in the present study. Each contributed with one pooled subgingival sample from the mesiobuccal surface of the four first molars. Samples were analysed using polymerase chain reaction for five serotypes of A. actinomycetemcomitans and the JP2 clone, using primers and conditions described previously. Subjects were stratified according to periodontal status (untreated periodontitis, non-periodontitis and periodontitis patients receiving supportive treatment). Comparisons between and within groups were performed by applying non-parametric tests (Kruskall-Wallis, Pearson χ(2) , z-test with Bonferroni's corrections and Kramer's V-test) at p=0.05 level. RESULTS: a. actinomycetemcomitans was detected statistically more frequently in untreated patients (27.5%) compared with the other two groups (11.7% for non-periodontitis and 10% for periodontitis patients receiving supportive treatment). No statistical differences were observed concerning the distribution of serotypes among groups (z-test with Bonferroni's corrections p>0.05). Serotype c was more predominant within the periodontally diseased groups (Kramer's V-test p<0.05). The JP2 clone was not detected. CONCLUSIONS: a. actinomycetemcomitans serotype b was not statistically correlated with periodontal disease in the investigated sample and the utility of microbiological testing before antimicrobial administration is emphasized.

The essential role of toll like receptor-4 in the control of Aggregatibacter actinomycetemcomitans infection in mice.

OBJECTIVE: Aggregatibacter actinomycetemcomitans is an oral Gram-negative bacterium that contributes to periodontitis progression. Isolated antigens from A. actinomycetemcomitans could be activating innate immune cells through Toll-like receptors (TLRs). In this study, we evaluated the role of TLR4 in the control of A. actinomycetemcomitans infection. MATERIAL AND METHODS: We examined the mechanisms that modulate the outcome of A. actinomycetemcomitans-induced periodontal disease in TLR4(-/-) mice. The production of cytokines was evaluated by ELISA. The bacterial load was determined by counting the number of colony-forming units per gram of tissue. RESULTS: The results showed that TLR4-deficient mice developed less severe periodontitis after A. actinomycetemcomitans infection, characterized by significantly lower bone loss and inflammatory cell migration to periodontal tissues. However, the absence of TLR4 facilitated the A. actinomycetemcomitans dissemination. Myeloperoxidase activity was diminished in the periodontal tissue of TLR4(-/-) mice. We observed a significant reduction in the production of tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta in the periodontal tissue of TLR4(-/-) mice. CONCLUSION: The results of this study highlighted the role of TLR4 in controlling A. actinomycetemcomitans infection.

Experimental infection of SPF pigs with Actinobacillus pleuropneumoniae serotype 9 alone or in association with Mycoplasma hyopneumoniae.

The purpose of this study was to compare in SPF pigs, the pathogenicity of an Actinobacillus pleuropneumoniae serotype 9 strain 21 (isolated from the palatine tonsils of a healthy gilt on a French nucleus pig farm, with no clinical signs or lung lesions but a highly positive reaction to A. pleuropneumoniae serotype 9 antibodies) with a pathogenic A. pleuropneumoniae strain 4915 serotype 9 (isolated in France from an outbreak of porcine pleuropneumonia). The pathogenicity of one Mycoplasma hyopneumoniae strain alone or associated with A. pleuropneumoniae strain 21 was also compared. Eight groups of 7 pigs were infected (at 6 or 10 weeks of age) and a control group was kept non-infected. Results showed that sensitivity to A. pleuropneumoniae was related to the age of the pig (6 weeks vs 10 weeks) whatever the strain. Surviving pigs infected at 6 weeks of age developed severe clinical signs, lung lesions typical of A. pleuropneumoniae and they seroconverted. In contrast, symptoms and lung lesions were almost non-existent in pigs infected with strain 21 at 10 weeks of age, but a seroconversion was observed with very high ELISA titres. These results were in accordance with those observed in the nucleus pig farm. Infection with M. hyopneumoniae alone induced typical mycoplasmal symptoms, pneumonia and seroconversion. Symptoms and lung lesions were the most noticeable in pigs infected with M. hyopneumoniae at 6 weeks of age and with A. pleuropneumoniae 4 weeks later. Our results show that the presence of A. pleuropneumoniae serotype 9 in a pig herd may be clinically unnoticed and that M. hyopneumoniae may potentiate A. pleuropneumoniae infection.

[Endocarditis due to Aggregatibacter (formerly: Actinobacillus) actinomycetemcomitans, a bacterium that grows in characteristic star-shaped colonies]. / Endocarditis door Aggregatibacter (voorheen: Actinobacillus) actinomycetemcomitans, een bacterie met karakteristieke stervormige kolonies.

A 72-year-old man, having had an artificial valve for almost 20 years now, presented with tiredness that had persisted for several weeks and reported weight loss of 5 kg. In more recent days he experienced fever and cold shivers, and an associated dry cough. Bearing in mind the potential for endocarditis, blood cultures were grown. In this, we identified a small, Gram-negative rod with a small, smooth, raised colony that grew slowly. We considered a micro-organism from the 'HACEK group', which is a group of micro-organisms including Haemophilus aphrophilus, Haemophilus paraphrophilus, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae and Aggregatibacter (formerly: Actinobacillus) actinomycetemcomitans. More careful observation revealed that the bacteria formed star-shaped colonies, proving that A. actinomycetemcomitans was the cause of this non-acute endocarditis. The patient received antibiotic treatment. Because non-acute endocarditis is often caused by hidden abnormalities in the mouth or teeth and A. actinomycetemcomitans plays an important role in severe cases of peridontitis, a dental surgeon was consulted. The dental surgeon diagnosed multifocal peridontitis and treated the patient, who was able to leave the hospital after 6 weeks of antibiotic treatment.

An unusual Actinobacillus equuli strain isolated from a rabbit with Tyzzer's disease.

Actinobacillus equuli was isolated in pure culture from the liver and lungs of an adult rabbit with Tyzzer's disease (Clostridium piliforme). Based on the haemolytic features on blood agar plates, a positive reaction in the CAMP-test, hydrolysis of esculin, the inability to ferment l-arabinose, tDNA-PCR and sequencing of the 16S rRNA gene, the isolate was classified as A. equuli subsp. haemolyticus biovar 1. However, the aqxA gene, characteristic for haemolytic A. equuli strains, was not detected by PCR.

Cerebral hemorrhage in infective endocarditis caused by Actinobacillus actinomycetemcomitans.

Cerebral hemorrhage occurs rarely in endocarditis caused by Actinobacillus actinomycetemcomitans. A 51-year-old man with a prosthetic mitral valve, who had been prophylactically treated (7 years) with warfarin, presented with intermittent fever. On admission, a Levine grade II/VI systolic cardiac murmur was detected. A transthoracic echocardiogram was negative for valve vegetation. Cefepime (1 g every 8 hours) was administered intravenously. On day 4, culturing of Gram-negative bacilli from blood and a transesophageal echocardiogram revealed a small oscillating filament attached to lateral mitral prosthetic ring on the atrial side. Ceftriaxone (2 g once daily) was started. Gait instability and left-side weakness developed abruptly 2 weeks later; brain magnetic resonance imaging revealed a hematoma over the right parietal-occipital lobe. Ceftriaxone was adjusted to 2 g every 12 hours. Actinobacillus actinomycetemcomitans was identified 3 weeks later. Recovery was achieved, with significant interval improvement and resolution of the cerebral lesions evident on CT.

Granulomatous lymphadenitis and pneumonia associated with Actinobacillus porcitonsillarum in a slaughter pig.

Multiple coalescing granulomatous foci were detected in the pulmonary hilar and mediastinal lymph nodes and lung of a slaughtered pig aged 6 months. Haemolytic, Gram-negative bacilli were isolated from the lymph nodes. The isolate (strain TO17214) strongly cross-reacted with sera against Actinobacillus pleuropneumoniae serotype 12 in slide agglutination tests. Comparative 16S rDNA gene sequencing analysis identified strain TO17214 as Actinobacillus porcitonsillarum. Histologically, extensive inflammation took the form of large granulomas consisting of epithelioid cells and multinucleated giant cells in the lymph nodes and lung, and Gram-negative bacilli were discernible in the centres of the lesions. Immunohistochemically, the organisms cross-reacted with polyclonal antibodies against A. pleuropneumoniae serotypes 12 and 2. The results indicated that A. porcitonsillarum, previously considered non-pathogenic, can induce multifocal granulomatous lymphadenitis accompanied by pneumonia in the growing-finishing pig.

Actinobacillus actinomycetemcomitans isolated from a case of cutaneous botryomycosis.

Cutaneous botryomycosis is an uncommon chronic suppurative bacterial skin infection that can mimic a fungal infection both clinically and histopathologically. Causative bacteria, most commonly Staphylococcus aureus, aggregate to form characteristic granules. We report the case of a 52-year-old black man who developed cutaneous botryomycosis of the hand following trauma. Routine bacterial cultures grew S aureus and Actinobacillus actinomycetemcomitans, a fastidious gram-negative bacillus known to cause periodontal disease, endocarditis, and actinomycosislike soft tissue infections. Despite culture-proven eradication of S aureus with long-term appropriate antibiotic therapy, the lesion, resolved only after fluoroquinolone treatment directed against A. actinomycetemcomitans, suggesting that A. actinomycetemcomitans was of etiologic significance.

Isolation of [Actinobacillus] rossii from an aborted piglet.

CASE REPORT: This report describes an investigation into the cause of abortions on a commercial pig farm in Victoria in October 2015 in which six sows aborted over a 2-month period. Four of the abortions occurred in the 3 weeks prior to the sows' anticipated farrowing dates and the other two occurred in the second trimester of pregnancy. An analysis of farm data showed that the abortion rate in the previous 12 months (2014-15) was more than twice that of the previous 2 years (1.2% vs 0.5%). Parity appeared not to be a risk factor for abortions. There were no other indicators of reproductive failure on the farm and there were no obvious clinical signs of disease in affected sows. Placenta and aborted fetuses for postmortem analysis were collected while one of the sows was aborting. The only gross abnormality detected in piglets was reddening over the skin. On gross examination the surfaces of the placentas appeared diffusely thickened and 'furry'. Histological examination of fixed placenta from one of two piglets showed a severe, acute, multifocal, necrosuppurative placentitis. Gram staining of a histological section of the placenta revealed abundant Gram-negative short bacilli, consistent with Pasteurella-Actinobacillus spp. A sample of stomach contents from one piglet yielded a profuse predominant growth of bacteria described as Pseudomonas-like. This organism was subsequently identified using 16sRNA sequencing to have 98% homology with [Actinobacillus] rossii. CONCLUSION: This is the first reported case of [A.] rossii isolated from an aborted pig's stomach in Australia.

Enriched Housing Reduces Disease Susceptibility to Co-Infection with Porcine Reproductive and Respiratory Virus (PRRSV) and Actinobacillus pleuropneumoniae (A. pleuropneumoniae) in Young Pigs.

Until today, anti-microbial drugs have been the therapy of choice to combat bacterial diseases. Resistance against antibiotics is of growing concern in man and animals. Stress, caused by demanding environmental conditions, can reduce immune protection in the host, influencing the onset and outcome of infectious diseases. Therefore psychoneuro-immunological intervention may prove to be a successful approach to diminish the impact of diseases and antibiotics use. This study was designed to investigate the effect of social and environmental enrichment on the impact of disease, referred to as "disease susceptibility", in pigs using a co-infection model of PRRSV and A. pleuropneumoniae. Twenty-eight pigs were raised in four pens under barren conditions and twenty-eight other pigs were raised in four pens under enriched conditions. In the enriched pens a combination of established social and environmental enrichment factors were introduced. Two pens of the barren (BH) and two pens of the enriched housed (EH) pigs were infected with PRRSV followed by A. pleuropneumoniae, the other two pens in each housing treatment served as control groups. We tested if differences in disease susceptibility in terms of pathological and clinical outcome were related to the different housing regimes and if this was reflected in differences in behavioural and immunological states of the animals. Enriched housed pigs showed a faster clearance of viral PRRSV RNA in blood serum (p = 0.014) and histologically 2.8 fold less interstitial pneumonia signs in the lungs (p = 0.014). More barren housed than enriched housed pigs developed lesions in the lungs (OR = 19.2, p = 0.048) and the lesions in the barren housed pigs showed a higher total pathologic tissue damage score (p<0.001) than those in enriched housed pigs. EH pigs showed less stress-related behaviour and differed immunologically and clinically from BH pigs. We conclude that enriched housing management reduces disease susceptibility to co-infection of PRRSV and A. pleuropneumoniae in pigs. Enrichment positively influences behavioural state, immunological response and clinical outcome in pigs.

Actinobacillus (Pasteurella) ureae meningitis in a HIV-positive patient.

Actinobacillus (Pasteurella) ureae is a commensal of the human nasopharynx that is a rare cause of meningitis. We present an HIV-infected patient with this condition. His case, and those previously reported in the literature, implicate head trauma or a neurosurgical procedure in the pathogenesis of this condition. The patient responded to initial empiric therapy with ceftriaxone, followed by intravenous penicillin.

Endarteritis and false aneurysm complicating aortic coarctation.

We report a tricky case of endocarditis because of the localization, aortic coarctation, and the pathogenic bacteria Actinobacillus actinomycetemcomitans. Furthermore, we underline the leading role of transesophageal echocardiography in the diagnosis of aortic endarteritis. First, aortitis was treated with antibiotics and, second, successfully operated on.

Rare Actinobacillus infection of the cavernous sinus causing painful ophthalmoplegia: case report.

OBJECTIVE AND IMPORTANCE: Actinobacillus actinomycetemcomitans is a gram-negative coccobacillus that is known to cause a wide array of clinical infections in debilitated patients, including periodontal disease, soft tissue abscess, pleural empyema, endocarditis, cerebral abscess, and meningitis. We report a rare A. actinomycetemcomitans cavernous sinus abscess that caused painful ophthalmoplegia in a healthy man. CLINICAL PRESENTATION: A 34-year-old man presented with a 3-month history of acute onset of left-sided retro-orbital pain that progressed to a complete left Cranial Nerve VI palsy and Cranial Nerve V1 and V2 hypesthesia. Magnetic resonance imaging revealed the presence of an enhancing lesion in the left cavernous sinus, which encased and narrowed the ipsilateral intracavernous segment of the internal carotid artery. Routine blood and cerebrospinal fluid analyses were normal. Tolosa-Hunt syndrome was suspected, and the patient was treated with high-dose corticosteroids. An open biopsy was performed after failed prolonged corticosteroid therapy. INTERVENTION: A left frontotemporal craniotomy and cavernous sinus exploration through an interdural approach were performed. A soft reddish mass was found in the cavernous sinus around Cranial Nerve V1 and V2. Multiple biopsies were obtained. Pathological analysis revealed a purulent infection containing multiple gram-negative coccobacilli. The patient's pain improved immediately, and cranial neuropathy resolved during the next several weeks. After cultures demonstrated growth of A. actinomycetemcomitans, a regimen of orally administered amoxicillin and metronidazole was initiated. Eight months after surgery, the patient was free of symptoms and a repeat magnetic resonance imaging scan was normal. CONCLUSION: We present a rare bacterial abscess of the cavernous sinus causing painful ophthalmoplegia. In patients who present with presumed Tolosa-Hunt syndrome and do not improve with prolonged high-dose corticosteroid therapy, an open biopsy is recommended to exclude a bacterial infection.

Actinobacillus actinomycetemcomitans endocarditis in hypertrophic obstructive cardiomyopathy.

We report a case of bacterial endocarditis due to Actinobacillus actinomycetemcomitans in a man with hypertrophic obstructive cardiomyopathy complicated by a mycotic aneurysm and thrombosis of the right common iliac artery. The patient was successfully treated with a combination of ampicillin and gentamicin, but was left with residual mitral incompetence.

Comparison of virulence of different Actinobacillus pleuropneumoniae serotypes and biotypes using an aerosol infection model.

An aerosol infection model for inoculation of pigs with Actinobacillus pleuropneumoniae is described. With this model the virulence of three A. pleuropneumoniae biotype 1 strains representing serotypes 2, 5b and 6, and one Danish biotype 2 were compared using 13-week-old pigs for inoculation. The pigs were sacrificed 24 h after aerosol exposure and lung lesions were evaluated. In pigs exposed to aerosols of suspensions containing 10(4) CFU/ml of serotypes 2, 5b and 6, a number of 5-10 lesions of haemorrhagic necrotizing pneumonia were induced. For the biotype 2 strain the dose creating similar lesions was 10(9) CFU/ml. Repeated experiments confirmed these results showing similar virulence of serotypes 2, 5b and 6 whereas the biotype 2 strain proved less virulent. The aerosol infection model allowed a comparison of the number of A. pleuropneumoniae CFU/liter air which were necessary to induce lung lesions in susceptible pigs. This indicates that the model will be well suited for virulence studies of A. pleuropneumoniae serotypes in pigs.