Infections of the Blood
Keith Struthers in Clinical Microbiology, 2017
The presence of bacteria in the blood requires identification of the likely source. There is the obvious association of Escherichia coli in blood and an ascending urinary tract infection (UTI). When native valve endocarditis is identified it can be straightforward to determine the likely source of the organism. The patient with endocarditis caused by a streptococcus of the mouth flora, such as Streptococcus sanguinis, can have poor dentition, and this needs to be addressed as part of the patient's management, usually involving the maxilla-facial surgical team. More unusual situations occur, and one is the identification of Streptococcus gallolyticus in blood culture. This organism is a minor member of the normal flora of the colon. However, it is recognized that there is an association that can develop between it and a large bowel malignancy, likely due to a specific interaction between the organism and these malignant cells. The streptococcus gains a selective growth advantage, from where it accesses the blood. Once in the blood it has the potential to initiate infective endocarditis. The finding of Streptococcus gallolyticus in blood culture, often in the setting of endocarditis, is an alert to investigate this malignancy; if found this is removed before any valve surgery.
ENT Emergencies
Anthony FT Brown, Michael D Cadogan in Emergency Medicine, 2020
This is more frequently viral than bacterial, but differentiating the two clinically is difficult. Fever above 38°C (100°F), tender cervical adenopathy, tonsillar exudate and absence of cough favour β-haemolytic Streptococcus, particularly in children aged 3–14 years.Glandular fever (EBV) presents with a grey, exudative tonsillitis typically in late adolescence.Other less common causes include CMV, herpes simplex, Mycoplasma pneumoniae, gonococcus and Chlamydia.
Streptococcus and Streptococcal Toxins
Dongyou Liu in Handbook of Foodborne Diseases, 2018
From a clinical point of view, infections associated with the streptococcal group of bacteria play a crucial role in determining the host status. As the pathogenicity of Streptococcus can be related with both classical and opportunistic pathogens, they contribute to infections starting from mild to severe symptoms. Identifying the molecular markers during the development of the disease process has improved the diagnosis of streptococcal diseases. Even though there are many technological interventions like contemporary genome sequencing, microarray technology, and proteome analysis to find the cues of host-pathogen interaction, collective use of these technologies could pave the way for understanding the global examination of molecular events. With the introduction of new, novel species, the pathogenicity associated with the Streptococcus genus is yet to be unveiled or understood completely. Identification of risk factors and underlying disease is indispensable and should be the subject of further studies.
Epidemiology of lower respiratory tract infections in adults
Published in Expert Review of Respiratory Medicine, 2019
Charles Feldman, Erica Shaddock
Research into the COPD microbiome, the community of commensal, symbiotic and pathogenic microorganisms, has demonstrated a significantly different organism community in the COPD subject to that found in healthy smokers and non-smokers [149]. Recent work by Wang and colleagues, with a larger sample size than previous studies, monitored the sputum of 87 COPD subjects during stable disease, during acute exacerbations and post recovery, demonstrated a dynamic microbiota [150]. They found an overall reduced microbial diversity within the sputum samples during acute exacerbations. There also appeared to be a small but nonsignificant shift toward an increase in the relative abundance of Proteobacteria (p = 0.42) and a decrease in Firmicutes (p = 0.73) during exacerbations. Moraxella demonstrated the greatest change during acute exacerbations, with an average increase of abundance of 5% (p = 0.22). Streptococcus spp., decreased by 3.8% (p = 0.58) and Haemophilus spp., increased by 3% (p = 0.57). Whilst none of these changes showed statistical significance, the findings are in agreement with previous studies, especially the decrease in microbial diversity and increased proportion of Proteobacteria. In most microbiome studies it appears that a decrease in microbial diversity results in disease which adds an interesting dynamic to the universal use of antibiotics in many of these conditions.
A nanocarrier system that potentiates the effect of miconazole within different interkingdom biofilms
Published in Journal of Oral Microbiology, 2020
Laís Salomão Arias, Jason L Brown, Mark C Butcher, Christopher Delaney, Douglas Roberto Monteiro, Gordon Ramage
Finally, analyzing the caries model biofilm, CFU data showed that yeast cells were reduced in number when exposed to MCZ only and the nanocarrier in comparison to the control group (Figure 6A). However, the same pattern was not observed for the CFE counting, as C. albicans cells reductions were comparable (Figure 6D). However, for all the bacterial species included in this model, there were reductions in the CFU and total CFE counts (Figure 6B, 6C and 6E and Supplementary Figure 3), with the exception for the CFE of streptococci following treatment with MCZ only (Supplementary 3A), and for the CFE of L. casei for both treatments (Supplementary Figure 3E). These results are also reflected in the percentages of the biofilm composition. C. albicans and L. casei increased their prevalence in the total number of cells for MCZ- and nanocarrier-treated biofilms (Figure 6G, Table 4 and Supplementary Table 1). Furthermore, the proportion of Streptococcus spp. in the biofilm treated with IONPs-CS-MCZ was reduced considerably when compared to the control (~1% for treated compared to ~17% for untreated).
Bacterial external ventricular catheter-associated infection
Published in Expert Review of Anti-infective Therapy, 2020
Kirsten R. I. S. Dorresteijn, Matthijs C. Brouwer, Korné Jellema, Diederik van de Beek
Cephalosporins are indicated for the treatment of Gram-negative Pseudomonas aeruginosa, Enterobacteriaceae spp. and as an alternative treatment in infections with Streptococcus spp. or Cutibacterium acnes. The penetration of cephalosporins in CSF is low secondary to the lipophilic aspect (high lipophilicity leads to protein binding and binding to the lipid membranes) [78]. Since high dosages of systemic therapy are, in general, well tolerated, adequate CSF concentrations can be achieved. The penetration of cefepime in CSF was analyzed in seven patients with EVDs and normal renal function who received cefepime for the treatment of nosocomial pneumonia [85]. Penetration into the CNS was 4–34% based on CSF minimum to serum minimum area under the curve ratio (median 0.08) and 5–58% based on minimum concentration ratio (median ratio 0.23, CSF min concentration median 1.8 µg/mL [range 0.1–2.5]), which were sufficient for many common nosocomial organisms. Cephalosporins (and penicillins and carbapenems) should not be given intraventricularly as they have been associated with an increased risk of seizures [15,86,87].
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