Gatifloxacin
M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson in Kucers’ The Use of Antibiotics, 2017
Activity against Gram-negative anaerobes, Bacteroides fragilis, other Bacteroides spp., Prevetella spp., Porphyromonas spp., and Fusobacterium spp. have been studied in vitro by a number of authors (Ackermann et al., 2000; Peric et al., 2004; Ednie et al., 1998; Schaumann et al., 1999; Kato et al., 1997; Dubreuil et al., 2003; Sheikh et al., 2015). As there are no CLSI breakpoints for these organisms, determining percentage susceptibility is difficult. For Bacteroides fragilis, MIC90 data are unhelpful, with values in different studies ranging from 1 to 16 μg/ml. If the only established CLSI breakpoints (trovafloxacin susceptible ≤ 2.0 μg/ml, intermediate 4.0 μg/ml, and resistant ≥ 8 μg/ml) are applied, percentage susceptibility ranges from 83% at 1.56 μg/ml (Kato et al., 1997), 90% at breakpoint ≤ 1 μg/ml (Schaumann et al., 1999), and 94% at 4 μg/ml (Dubreuil et al., 2003). Most strains of Porphyromonas spp., Fusobacterium spp., and Prevotella spp. were susceptible (Kato et al., 1997). In general, activity is similar to or slightly less than that of moxifloxacin or garenoxacin (Appelbaum, 1999; Schaumann et al., 2013).
Lipopolysaccharide from Oral Bacteria: Role in Innate Host Defense and Chronic Inflammatory Disease
Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison in Endotoxin in Health and Disease, 2020
In contrast, there is a clear association between an increase in the number of gram-negative bacteria that can be isolated from dental plaque samples and disease. The total number of bacteria that can be isolated from clinically healthy sites is usually between 102–103 bacteria, of which approximately 15% are gram-negative. Gingivitis, a disease characterized by an increase in the redness and swelling of the gingiva surrounding the tooth root surface (and an analogous increase in the number and types of inflammatory cells), is associated with an increased microbial load (104–105 organisms), of which 15–50% are gram-negative bacteria. Periodontitis, a chronic inflammatory disease, which results in the loss of connective tissue and the alveolar bone that surrounds and supports the tooth root, has a further increase in microbial load (105–108 organisms) and a clear association with specific gram-negative bacteria (3). A recent World Workshop on Periodontal Disease (9) has identified Porphyromonas gingivalis, Bacteroides forsythus, and Actinobacillus actinomycetemcomitans, three gram-negative bacteria, as agents of disease, as opposed to merely being associated with disease, in recognition of the important role of these bacteria in the induction of periodontitis.
Infection-driven periodontal disease
Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald in Principles of Mucosal Immunology, 2020
The relationship of specific periodontal bacteria and the host response is complex, and how these bacteria evade clearance by the inflammatory/immune response is an area of significant interest. Much of the focus has been given to the putative pathogen Porphyromonas gingivalis because of its frequent association with periodontal disease lesions and its capacity as a keystone pathogen, as described earlier. Evasion of the host response takes many forms and, from a natural selection standpoint, benefits the oral organisms by promoting chronic inflammation that produces abundant sources of collagen peptides and heme-containing compounds. Proposed mechanisms that have been demonstrated in vitro or in animal models include inhibition of leukocyte recruitment by Porphyromonas gingivalis lipopolysaccharide (LPS) binding to host adhesion molecules (ICAM-1, E-selectin), inhibition of IL-8 production by intracellular dephosphorylation of serine 536 on the p65 subunit of nuclear factor (NF)-κB, degradation of FMLP and C5a peptides by gingipains that directly disrupt a chemotactic gradient, and PI3K activation and inhibition of RhoA GTPase. LPS and lipid A have been shown to delay neutrophil apoptosis through toll-like receptor (TLR)2 signaling. LPS of Porphyromonas gingivalis displays significant structural heterogeneity that is mediated by lipid A phosphatases produced by the organism. It is postulated that the lipid A remodeling by the organism is necessary for colonization and contributes to the initiation of commensal organism dysbiosis.
Phylogenetic diversity in fim and mfa gene clusters between Porphyromonas gingivalis and Porphyromonas gulae, as a potential cause of host specificity
Published in Journal of Oral Microbiology, 2020
Kaori Fujiwara-Takahashi, Takayasu Watanabe, Masahiro Shimogishi, Masaki Shibasaki, Makoto Umeda, Yuichi Izumi, Ichiro Nakagawa
The genus Porphyromonas contains Gram-negative anaerobic bacilli, and was formerly classified in the genus Bacteroides [1]. Species in the genus Porphyromonas are prevalent in the oral cavity of mammals [2–5]. Among them, Porphyromonas gingivalis is most widely known as a periodontopathic bacterium in humans [6]. Compared to other human oral bacteria, P. gingivalis has been extensively studied and characterized because it is one of the few oral bacteria that can be isolated and cultured, and produces various virulent factors such as proteases [6]. P. gingivalis is classified as a member of the red complex species, which are highly detectable in deep periodontal pockets [7]. In recent, P. gingivalis was called a keystone species, which has substantial effects on a bacterial community despite its low abundance [8], and is therefore still influential in the etiology of periodontitis.
Relationship between nasopharyngeal microbiota and patient’s susceptibility to viral infection
Published in Expert Review of Anti-infective Therapy, 2019
Grégory Dubourg, Sophie Edouard, Didier Raoult
During the infection, an increased diversity has been however noticed among children infected by influenza A virus along with a decrease of usual commensals (i.e. Moraxella, Staphylococcus, Corynebacterium and Dolosigranulum) and an increase of the genus Streptooccus [59]. This latter increase was also associated with severe acute respiratory infection in another study [63]. The increase in diversity was also associated with the severity of symptoms compared to mild influenza in children. At the taxa level., Porphyromonas spp.,., Fusobacterium spp., Lachnospiracea spp., Veillonella spp., Prevotella spp. (that are all strict anaerobes), Granulicatella spp Streptobaccillus spp and Haemophilus spp. were found to be predictive of severe forms of influenza in children, while S. aureus is associated with the benign form [16]. Association between differential composition of nasopharyngeal microbiota at the taxa level is however inconsistent [59], and it is important to note that the subjects with mild and severe forms are not age-matched. These differences could be due to a differential maturation of the nasopharyngeal microbiota between children. Interestingly, the carriage of influenza without symptoms did not lead to substantial changes of the nasopharyngeal microbiota composition, while only one healthy subject was included among the influenza-positive subjects (1.9%) in the study of Edouard et al. [17]. This finding has indeed to be confirmed in a larger study including healthy influenza carriers.
Brazilian red propolis reduces orange-complex periodontopathogens growing in multispecies biofilms
Published in Biofouling, 2019
Stela Lima Farias Miranda, Jennifer Toledo Damasceno, Marcelo Faveri, Luciene Figueiredo, Helio Doyle da Silva, Severino Matias de Alencar Alencar, Pedro Luiz Rosalen, Magda Feres, Bruno Bueno-Silva
Multispecies biofilms are considered the primary etiological factor triggering the onset and development of periodontal diseases. Different bacterial species can thrive in subgingival sites and produce destructive factors and enzymes that degrade the extracellular matrix and human cell membranes to obtain nutrients for microbial cell growth and tissue invasion. Porphyromonas gingivalis has been considered the keystone pathogen in periodontal disease. This bacterial species produces virulence factors named gingipains, which can subvert the human immune complement system and thereby enable the establishment of dysbiotic subgingival microbiota. Another virulence factor produced by P. gingivalis is FimA, a fimbrial protein that inhibits the complement system receptor in macrophages. The presence of a pathogenic microbiota leads to an exacerbated inflammatory response, which ultimately results in destruction of periodontal support tissues, with progressive clinical attachment loss and eventual tooth loss (Papapanou et al. 2018).
Related Knowledge Centers
- Anaerobic Organism
- Spore
- Gram-Negative Bacteria
- Porphyromonadaceae
- Salivary Microbiome
- Microbiome Project
- Porphyromonas Gingivalis
- Porphyromonas Catoniae
- Porphyromonas Pasteri
- Porphyromonas Somerae