Study of antimicrobial effects of functionalized silver nanoparticles

In recent decades, the study of nanoparticles (NPs) has gained a great scientific interest, due to a wide range of potential applications, in different fields: electronic, optical and biomedical. Some of the most studied effects of NPs are antibacterial ones, because the large, sometimes unjustified and uncontrolled administration of antibiotics has led to the emergence of multidrug-resistant (MDR) bacterial strains. In our study, starting from silver nitrate (AgNO3), we made approximately 30 nm spherical AgNPs that were coated with a thin layer of ethylene glycol (EG) or EG and polyvinylpyrrolidone (PVP). The microbial culture study showed that AgNPs have antibacterial effects, depending on the dose of the NPs and the type of bacteria.

Immunohistochemistry predictive markers for primary colorectal cancer tumors: where are we and where are we going?

The aim of our study is to highlight and organize the recently published immunohistochemistry (IHC) predictive biomarkers of primary colorectal cancers (CRCs) that could lead to practical implementation. We reviewed articles that examined CRC samples with significant statistic correlation between the IHC marker expression and disease progression over time, relationships with the available clinical features and those who detect the prognosis of drug effects. Our analysis showed that nine markers could correlate with medical treatment response of CRCs in different stages. When using better overall survival (OS) and better disease-free survival (DFS) as a grouping factor, there were 14 markers that could be used in assessing CRC prognosis. By using poor prognostic for the OS and the DFS as a grouping factor, we found 43 markers. Subgroup analysis was also performed based on the 32 markers recently confirmed to predict metastasis evolution or the recurrence risks. Venous invasion could be predictable for tumors, statistically significant metastasis susceptibility was observed for markers and also the capacity to evaluate recurrence. CRCs integrate a variety of localizations and there are proofs that distinguish the sites of tumors. The studies reporting data specifically for rectal cancer separating it from colon cancer contained seven IHC markers. In order to be able to implement a predictive biomarker in clinical practice, it must comply with certain criteria as clinical value and analytical proof. Unique biological signature of CRC can be distinguished by identifying biomarkers expression. Several markers have shown potential, but the majority still need to render clinical utility.

Susceptibility testing of Streptococcus pneumoniae and Viridans streptococcal isolates against: quinolones, oxazolidinones and glycopeptides

The aim of this study was to test the susceptibility of 100 strains (pneumococci and viridans streptococci) isolated from oral and respiratory tract infections and their complications, against one antibiotic of each of the following classes: quinolones, oxazolidinones and glycopeptides.

MATERIAL AND METHODS

The Etest has been used in order to investigate the susceptibility of the isolates against levofloxacin, linezolid and vancomycin.

RESULTS AND CONCLUSIONS

As expected, the results of the study indicated that all isolates were susceptible to linezolid and vancomycin. In contrast to the pneumococcal isolates, which were all susceptible to levofloxacin, 10% of the viridans strains showed resistance to this quinolone. When fluoroquinolones are needed as an alternative to the beta-lactam antibiotics in infections in which oral streptococci are involved, the in vitro susceptibility testing is required.

Contribution towards developing a new semi-selective medium for Streptococcus anginosus group

The aim of this study was to develop a new selective medium for isolation of Streptococcus anginosus group (SAG) strains, by adding sulphamethazine and aztreonam as selective agents at Mitis-Salivarius agar (MSA), the medium commonly used for recovery of oral streptococci from oral samples.

MATERIAL AND METHOD

The evaluation of Mitis-Salivarius--sulphamethazine--aztreonam agar (MSSAA) for SAG selectivity was performed by testing the growth of type strains and laboratory-stored clinical isolates of different oral streptococcal species on this medium and also by investigating the SAG recovery on MSSAA in comparison with MSA and the growth inhibition of non-SAG strains from 100 saliva and 11 pus samples (collected from healthy young subjects and from paediatric patients with upper respiratory tract infections, respectively) on MSSAA.

RESULTS

The same SAG recovery rate was obtained on both MSSAA and MSA, while non-SAG strains failed to grow on the novel medium, except for enterococci. The results of the present study have indicated that MSSAA is a suitable medium for selecting SAG isolates from clinical specimens.

[Anaerobic Gram-negative bacilli involved in the etiopathogeny of the abscesses of superficial fascial spaces of the face and neck]

The aim of this study was to isolate and identify at species level the strains of anaerobic Gram-negative bacilli (GNB) from pus samples collected in patients with abscesses of fascial spaces of the face and neck. Microscopy of Gram-stained smears and cultures were performed in each specimen. The strictly anaerobic GNB strains were identified using the conventional methods of diagnosis and the Rapid ID 32 A system. In addition, the other strains isolated in association with these bacteria were identified at least to genus level. The 28 anaerobic GNB isolates belonged to: Fusobacterium nucleatum and different species of Prevotella (4 species) and Bacteroides (3 species).

CONCLUSIONS

The anaerobic GBN strains were recovered--either alone or in association with other migroorganisms--in more than half of all investigated samples and represented about 40% of all isolates. The most frequently isolated species were P> melaninogenica and B. ureolyticus.

[Epidemiologic aspects of the edentulous mouth (II). General and local features of the totally edentulous mouth]

PREMISES AND AIM: The study wants to reveal the general and local clinical aspects, which may accompany the completely edentulous mouth and create difficulties in treatment.

MATERIAL AND METHOD

The clinical and statistical study was carried out on 40 edentulous patients; we analyzed general aspects (the present medical status, the patient's medication and its effects) and local aspects (the etiology, the type of previous denture treatment, the type and number of denture's repairs, the extent of the residual ridge resorption, the relationship between residual ridges), the total difficulty of the treatment.

RESULTS AND DISCUSSIONS

80% of the edentulous patients suffered from general diseases, more frequent from cardiovascular, digestive, metabolic, renal, rheumatic diseases. 73% of the edentulous patients received daily medication, which generated in 30% of cases a decrease of the saliva volume. The demand for prosthetic treatment was greater for the recent edentulous patients (less then 1-2 years of edentulousness) or for those who lost their teeth more then 6 years ago. The majority of patients over 70 years are completely bimaxillary edentulous patients, 68% of them had previous bimaxillary dentures. We found the bone resorption moderate (50% of cases) and severe (33% of patients), the relationship of the residual ridges inverse in the anterior and posterior zones (60% of patients) and normal in the anterior zone and inverse in the posterior zone (28%). The difficulty of the treatment was frequently 3Pd degree for the maxilla and 4t' degree for the mandible (the maximum degree of difficulty).

CONCLUSIONS

The completely edentulous patient presents a number of general and local modifications, which increase the difficulty of the treatment, demand supplementary therapeutic procedures, and increase the total cost. The modifications of the oral structures demand specific therapeutic procedures, and in some cases the frequent renewal or adaptation of dentures (every 3-5 years); all those costs must be took over by the insurance company, because of their social status (pensioners).

[Phenotypical characterization of some strains of anginosus streptococci isolated from superficial face and neck abscesses]

The aim of the present study was to identify at species level and to characterize the strains of streptococci belonging to anginosus group isolated from 30 pus samples collected from patients with abscesses of fascial spaces of the face or neck. The identification of facultatively anaerobic Gram-positive cocci in chains at genus level was made by conventional diagnosis methods and at species level by the help of Rapid ID 32 STREP system. The cultural, biochemical and antigenic (limited at Lancefield Group identification by Slidex Strepto-Kit) characterization was performed in the mean time with the species identification. The anginosus streptococcal strains were isolated either in association with other bacteria or in pure culture and S. anginosus isolates clearly predominated. As expected, the anginosus streptococcal strains were found to be heterogeneous regarding the cultural, biochemical and antigenic features.

[Epidemiologic aspects of the totally edentulous mouth. (1) General aspects]

PREMISES AND AIM: This study analyses the evolution of the populational segment represented by edentulous patients, specific to our country, regarding the number of edentulous patients, related to age, sex.

MATERIAL AND METHOD

We performed two statistical studies on edentulous patients in 1994 and in 2004 and we compared their results. In order to evaluate the present clinical aspects of the edentulous patients, we performed this year a clinical study on 40 patients, which were classified according to their age and sex. We compared the data from this study to those obtained ten years ago from another study performed on 360 edentulous patients.

RESULTS

Comparing those two studies we could appreciate the evolution of the edentulous related to age, number of patients on age groups, patient's age when he (she) became edentulous, the age/sex ratio. The age of edentulousness's installation increased, but there still exist numerous edentulous patients on the age groups 60-70, 70-80 years. In this year study, the number of edentulous patients over 80 years is twice the number that we found ten years ago. The ratio age/sex is maintained the same in both studies. So, there are more women than man in the age groups 50-60, and 60-70 (multiplied by 2, respectively 2,5), and an almost equal number of man and women in the age groups of 70-80 years and over 80 years.

CONCLUSIONS

The clinical evaluation of the edentulous patients in this study, related to age and to the age/sex ratio revealed modifications in other populational groups, i.e., the increasing age of the installation of edentulousness and the increasing number of elderly people result in a greater number of edentulous female patients after menopause. So we can find out practical conclusions for the realization of total dentures, regarding treatment attitudes and costs.

[Prevotella species involved in the onset of superficial face and neck abscesses]

The aim of the study was to identify at species level the Prevotella strains from 30 pus samples collected by needle aspiration in patients with abscesses of fascial spaces of the face and neck. Microscopy of Gram-stained direct smear and cultures on selective and nonselective media incubated aerobically and anaerobically were performed in each pus specimen. All strains of Gram-negative strictly anaerobic bacilli were identified to genus and species level using conventional methods of diagnosis and the Rapid ID 32 A system (BioMérieux, Marcy-l'Etoile, France). The Prevotella isolates were recovered (alone or in association with other bacteria) in 46.6% of the investigated specimens and were represented in reverse order of frequency by the following species: P. melaninogenica, P. denticola, P. oralis and P. loescheii. In conclusion, the rate of Prevotella isolation was relatively high and the most frequently isolated species was P. melaninogenica (followed by P. denticola), while no P. intermedia was found.

Antimicrobial susceptibility of some streptococci strains of anginosus group isolated from oral and maxillofacial infections

Streptococci strains of the anginosus group isolated from various oral and maxillofacial infections (OMF) were screened for their susceptibility to the following antimicrobial agents: benzylpenicillin, ampicillin, oxacillin, cephalothin, ceftazidime, cefotaxime, cefuroxime, erythromycin, clindamycin, tetracycline, chloramphenicol, vancomycin and trimethoprime-sulphamethoxazole. The isolates were susceptable to: clindamycin, chloramphenicol, vancomycin and all beta-lactam antibiotics, except ceftazidime to which 54.5% of the strains showed intermediate susceptibility. Intermediate susceptibility to tetracycline was found in 11.3% of the strains, whereas resistance to the same antibiotic was demonstrated in 61.4%. Resistance to erythromycin and trimethoprime-sulphamethoxazole was of 2.3% for both. In conclusion, penicillin is the drug of choice in infections caused by streptococci of the anginosus group.

Streptococci species of anginosus group isolated from oral and maxillofacial infections

The aim of the study was to isolate and identify at species level streptococci strains of anginosus group in pus samples collected from 110 patients with oral and maxillofacial (OMF) infections. Gram-stained smears and cultures on selective and nonselective media were done from each of the 111 pus samples (2 samples were collected from one of the patients, who presented 2 oral abscesses at the same time). The isolates were identified on the basis of cultural and biochemical characteristics. Speciation of the anginosus group isolates was performed using the Rapid ID 32 Strep system (Bio Mérieux, France). Fourty-four anginosus group strains were isolated from 42 patients. Fourty of these isolates were identified as Streptococcus anginosus (2 nonidentical isolates were found in 2 patients), 3 isolates as Streptococcus constellatus and only one as Streptococcus intermedius. The study confirmed that the anginosus group is often involved in OMF infections alone or in association with other aerobic and/or anaerobic bacteria. In the investigated cases, Streptococcus anginosus was by far the most frequently isolated species within the anginosus group.

Phenotypic characterization of some anginosus group isolates from oral and maxillofacial infections

The aim of this study was to briefly characterize serologically, biochemically and from the cultural point of view some anginosus group isolates found in pus samples collected from patients with oral and maxillofacial infections. Cultural characterization was done by studying the culture odor, the colony size and aspect, and hemolysis type on Columbia bood agar (BA). Lancefield grouping was made on cards using the rapid latex-agglutination test (Slidex Strepto-Kit, Bio Mérieux, France). The biochemical characterization was performed at the same time with the speciation by the Rapid ID 32 Strep system (Bio Mérieux, Marcy-l'Etoile, France). The anginosus group isolates were phenotypically heterogenic. Based on phenotypic description, nonidentical anginosus group isolates were found in the same patient sample.

Isolation and speciation of Prevotella strains from periodontal abscesses

The aims of the study were to isolate and to identify at species level the Prevotella strains in pus samples collected by needle aspiration from 25 Romanian patients with periodontal abscesses. Gram-stained smears and cultures on selective and nonselective media were performed from each of the 25 pus samples. The isolates were identified on the basis of Gram staining, cultural characteristics and standard biochemical reactions. The Gram-negative anaerobic bacilli isolates were biochemically characterized and identified at species level using the Rapid ID 32 A system (Bio Mérieux, France). Fifteen Prevotella isolates belonging to one of the following species: P. melaninogenica, P. denticola, P. oralis, P. loescheii and P. bivia were recovered. All Prevotella isolates reacted similarly in 20 tests in the Rapid ID 32 A system. The P. melaninogenica strain showed approximately the same biochemical profile and only two sugar fermentation tests were not constantly positive. The study confirmed that Prevotella is often involved in periodontal abscesses (> 50% of the cases) in association with other anaerobic or/and aerobic bacteria. P. melaninogenica was the most frequently isolated Prevotella species from the investigated cases.

Significance of the positivity of some ELISA tests different as concerning the antigenic source in interpreting the western blot indeterminate sera in monitoring the epidemiology of high risk populations

The paper analyses 50 pairs of sera pre-elevated within the "sentinel" epidemiological surveillance in a population exposed to a high risk at a 2 months interval. At the first determination all these sera showed an indeterminate Western Blot pattern; after 2 months, 93.7% revealed the occurrence of a certainly positive pattern. The paper is an analysis of the way in which different ELISA kits diagnosed at the first determination the Western Blot indeterminate sera. The purpose of the paper is to adopt a methodology of accurately diagnosing HIV infections in a population exposed to a high risk within an epidemiological surveillance of the "sentinel" type where the receiving of a second serum sample is quite difficult.