Pionefrosis por Lelliottia amnigena / Pyonephrosis by Lelliottia amnigena

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The in vivo extracellular life of facultative intracellular bacterial parasites: role in pathogenesis.

Classically labeled facultative intracellular pathogens are characterized by the ability to have an intracellular phase in the host, which is required for pathogenicity, while capable of extracellular growth in vitro. The ability of these bacteria to replicate in cell-free conditions is usually assessed by culture in artificial bacteriological media. However, the extracellular growth ability of these pathogens may also be expressed by a phase of extracellular infection in the natural setting of the host with pathologic consequences, an ability that adds to the pathogenic potential of the infectious agent. This infective capability to grow in the extracellular sites of the host represents an additional virulence attribute of those pathogens which may lead to severe outcomes. Here we discuss examples of infectious diseases where the in vivo infective extracellular life is well documented, including infections by Francisella tularensis, Yersinia pestis, Burkholderia pseudomallei, Burkholderia cenocepacia, Salmonella enterica serovar Typhimurium and Edwardsiella tarda. The occurrence of a phase of systemic dissemination with extracellular multiplication during progressive infections by facultative intracellular bacterial pathogens has been underappreciated, with most studies exclusively centered on the intracellular phase of the infections. The investigation of the occurrence of a dual lifestyle in the host among bacterial pathogens in general should be extended and likely will reveal more cases of infectious diseases with a dual infective intracellular/extracellular pattern.

Increased levels of Porphyromonas gingivalis are associated with ischemic and hemorrhagic cerebrovascular disease in humans: an in vivo study.

OBJECTIVE: This study investigated the role of periodontal disease in the development of stroke or cerebral infarction in patients by evaluating the clinical periodontal conditions and the subgingival levels of periodontopathogens. MATERIAL AND METHODS: Twenty patients with ischemic (I-CVA) or hemorrhagic (H-CVA) cerebrovascular episodes (test group) and 60 systemically healthy patients (control group) were evaluated for: probing depth, clinical attachment level, bleeding on probing and plaque index. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were both identified and quantified in subgingival plaque samples by conventional and real-time PCR, respectively. RESULTS: The test group showed a significant increase in each of the following parameters: pocket depth, clinical attachment loss, bleeding on probing, plaque index and number of missing teeth when compared to control values (p<0.05, unpaired t-test). Likewise, the test group had increased numbers of sites that were contaminated with P. gingivalis (60%x10%; p<0.001; chi-squared test) and displayed greater prevalence of periodontal disease, with an odds ratio of 48.06 (95% CI: 5.96-387.72; p<0.001). Notably, a positive correlation between probing depth and the levels of P. gingivalis in ischemic stroke was found (r=0.60; p=0.03; Spearman's rank correlation coefficient test). A. actinomycetemcomitans DNA was not detected in any of the groups by conventional or real-time PCR. CONCLUSIONS: Stroke patients had deeper pockets, more severe attachment loss, increased bleeding on probing, increased plaque indexes, and in their pockets harbored increased levels of P. gingivalis. These findings suggest that periodontal disease is a risk factor for the development of cerebral hemorrhage or infarction. Early treatment of periodontitis may counteract the development of cerebrovascular episodes.

Increased levels of Porphyromonas gingivalis are associated with ischemic and hemorrhagic cerebrovascular disease in humans: an in vivo study

OBJECTIVE: This study investigated the role of periodontal disease in the development of stroke or cerebral infarction in patients by evaluating the clinical periodontal conditions and the subgingival levels of periodontopathogens. MATERIAL AND METHODS: Twenty patients with ischemic (I-CVA) or hemorrhagic (H-CVA) cerebrovascular episodes (test group) and 60 systemically healthy patients (control group) were evaluated for: probing depth, clinical attachment level, bleeding on probing and plaque index. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were both identified and quantified in subgingival plaque samples by conventional and real-time PCR, respectively. RESULTS: The test group showed a significant increase in each of the following parameters: pocket depth, clinical attachment loss, bleeding on probing, plaque index and number of missing teeth when compared to control values (p<0.05, unpaired t-test). Likewise, the test group had increased numbers of sites that were contaminated with P. gingivalis (60 percentx10 percent; p<0.001; chi-squared test) and displayed greater prevalence of periodontal disease, with an odds ratio of 48.06 (95 percent CI: 5.96-387.72; p<0.001). Notably, a positive correlation between probing depth and the levels of P. gingivalis in ischemic stroke was found (r=0.60; p=0.03; Spearman's rank correlation coefficient test). A. actinomycetemcomitans DNA was not detected in any of the groups by conventional or real-time PCR. CONCLUSIONS: Stroke patients had deeper pockets, more severe attachment loss, increased bleeding on probing, increased plaque indexes, and in their pockets harbored increased levels of P. gingivalis. These findings suggest that periodontal disease is a risk factor for the development of cerebral hemorrhage or infarction. Early treatment of periodontitis may counteract the development of cerebrovascular episodes.

Infección por bacilos gram-negativos no fermentadores: Problemática en las unidades de cuidados intensivos / Infection caused by the nonfermentative gram-negative bacilli. Problematic in the intensive cares units

Las infecciones por bacilos gram-negativos no fermentadores han cobrado notoria importancia por su incidencia en las infecciones hospitalarias. Actualmente, se destaca el hallazgo de especies como la Pseudomonas aeruginosa y el Acinetobacter spp.; de este último, el Acinetobacter baumannii es la especie que con mayor frecuencia se asocia a infecciones graves y a la muerte. El aislamiento de estos patógenos se asocia a un incremento de la mortalidad y están entre los agentes que más frecuentemente causan infecciones en las Unidades de Terapia Intensiva, de ahí que constituyan desafíos terapéuticos. En el presente artículo, se realiza una revisión actualizada de la literatura y se hace énfasis en la problemática de la resistencia bacteriana y la terapéutica antibiótica(AU)

Infections caused by the nonfermentative gram-negative bacilli have charged notorious importance for their incidence in the hospital infections. At the moment it stands out the discovery of species like the Pseudomonas aeruginosa and the Acinetobacter spp.; Acinetobacter baumannii is the species that associates to severe infections and the death with more frequency. The isolation of these pathogens associates to an increment of the mortality. These pathogens are among the agents that more frequently cause infections in the Intensive Cares Units, they constitute therapeutic challenges. Presently article is made a modernized revision of the literature and emphasis is made in the problem of the bacterial resistance and the antibiotic therapy(AU)

A review of necrotising fasciitis in the extremities.

OBJECTIVE: To review currently available evidence on the epidemiology and methods of management for necrotising fasciitis, with particular reference to Hong Kong. DATA SOURCES AND STUDY SELECTION: Medline, PubMed, and Cochrane Library searches of local and internationally published English language journals, from 1990 to July 2008 using the terms 'necrotising fasciitis', 'Hong Kong', 'diagnosis', 'epidemiology', 'vibrio', 'streptococci', 'clostridia', and 'management'. DATA EXTRACTION: All articles involving necrotising fasciitis in Hong Kong were included in the review. DATA SYNTHESIS: The incidence of necrotising fasciitis in Hong Kong and around the world has been increasing. This rapidly progressive infection is a major cause of concern, due to its high morbidity and mortality. Up to 93% of affected patients at our hospital were admitted to the Intensive Care Unit and many still died from septic complications, such as pneumonia and multi-organ failure. Radical debridements in the form of amputations and disarticulations were considered vital in 46% of the patients. Early recognition and treatment remain the most important factors influencing survival. Yet, early diagnosis of the condition is difficult due to its similarities with many other soft tissue disorders such as cellulitis. Repeated surgical debridement or incisional drainage continues to be essential for the survival of sufferers from necrotising fasciitis. Many authorities have reported that carrying out the first fasciotomy and radical debridement within 24 hours of symptom onset was associated with significantly improved survival, which also emphasises the importance of early diagnosis. CONCLUSION: Clinicians must adopt a high index of suspicion for necrotising fasciitis. Empirical antibiotics must be started early and repeated physical examinations should be performed, while maintaining a low threshold for tissue biopsy and surgery. The timing of the first fasciotomy and radical debridement within a window of 24 hours from symptom onset is associated with significantly improved survival.

[Hydrophobic properties of gram-negative rods colonizing upper respiratory tract of healthy people]. / Hydrofobowe wlasciwosci paleczek gram-uje- mnych kolonizujacych górne drogi oddechowe zdrowych osób.

The cell surface hydrophobicity is one of the non specific factors of adhesion influencing the ability of microorganisms to colonize nasopharynx. The aim of this paper was to evaluate via salt aggregation test (SAT) the cell surface hydrophobicity of 150 strains of gram-negative rods isolated from the throat or/and nasal specimens of healthy people. It has been found that among the nonfermenting rods hydrophobic strains were predominant. In contrast, the isolates of Enterobacteriaceae family were characterized by the distinctive features of the cell surface within particular genera or even species. The obtained results show that, despite differences in cell surface hydrophobicity, numerous species of gram-negative rods have the ability to colonize the mucous membrane of upper respiratory tract. This suggests that the cell surface hydrophobicity is rather a feature of species or genus, but it is not related to the ecological niche of microorganisms in human body.

Studying M cells and their role in infection.

In addition to sampling antigens, M cells are a common route for pathogen invasion. Recent studies have partly defined the mechanisms by which pathogens interact with and exploit M cells as a gateway into the host. New research tools are facilitating studies on M cell infection, differentiation and function.

Biochemical and pathogenic properties of Shewanella alga and Shewanella putrefaciens.

We characterized 49 strains of Shewanella spp. from clinical (n = 31) and nonhuman (n = 18) sources. Most Shewanella alga organisms (Gilardi biovar 2; Centers for Disease Control and Prevention [CDC] biotype 2) originated from clinical material (92%), failed to produce acid from carbohydrates other than D-ribose, and were biochemically and enzymatically fairly homogeneous. In contrast, Shewanella putrefaciens organisms (Gilardi biovars 1 and 3; CDC biotype 1) were more often associated with nonhuman sources (70%), were able to utilize a number of sugars (sucrose, L-arabinose, and maltose), and were found to exhibit wider variations in biochemical characteristics; three biotypes within S. putrefaciens were detected. Notable differences between the two species in enzymatic activity, determined with the API-ZYM system (bioMérieux, Hazelwood, Mo.), and cellular fatty acid profiles, determined by the MIDI system (Microbial ID Inc., Newark, Del.), were also detected. Pathogenicity studies of mice indicate that S. alga appears to be the more virulent species, possibly due to the production of a hemolytic substance.

Vaccination against enteric pathogens: from science to vaccine trials.

Recent advances in scientific research and clinical trials have shown promise for vaccine development against enteric pathogens. Identification of new virulence factors, such as the two distinct shigella enterotoxins, has allowed the development of new immunogen or new attenuated strains. Improved knowledge facilitated the development of safer attenuated live microorganism and construction of multivalent vaccines. Finally, an important advantage is the use of nonreplicating plasmid DNA vectors to express protective antigens in the host.

Root colonization and systemic spreading of Azoarcus sp. strain BH72 in grasses.

The invasive properties of Azoarcus sp. strain BH72, an endorhizospheric isolate of Kallar grass, on gnotobiotically grown seedlings of Oryza sativa IR36 and Leptochloa fusca (L.) Kunth were studied. Additionally, Azoarcus spp. were localized in roots of field-grown Kallar grass. To facilitate localization and to assure identity of bacteria, genetically engineered microorganisms expressing beta-glucuronidase were also used as inocula. beta-Glucuronidase staining indicated that the apical region of the root behind the meristem was the most intensively colonized. Light and electron microscopy showed that strain BH72 penetrated the rhizoplane preferentially in the zones of elongation and differentiation and colonized the root interior inter- and intracellularly. In addition to the root cortex, stelar tissue was also colonized; bacteria were found in the xylem. No evidence was obtained that Azoarcus spp. could reside in living plant cells; rather, plant cells were apparently destroyed after bacteria had penetrated the cell wall. A common pathogenicity test on tobacco leaves provided no evidence that representative strains of Azoarcus spp. are phytopathogenic. Compared with the control, inoculation with strain BH72 significantly promoted growth of rice seedlings. This effect was reversed when the plant medium was supplemented with malate (0.2 g/liter). N2 fixation was apparently not involved, because the same response was obtained with a nifK mutant of strain BH72, which has a Nif- phenotype. Also, Western blot (immunoblot) analysis of protein extracts from rice seedlings gave no indication that nitrogenase was present. PCR and Western immunoblotting, using primers specific for eubacteria and antibodies recognizing type-specific antigens, respectively, indicated that strain BH72 could colonize rice plants systemically, probably mediated by longitudinal spreading through vessels.