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Antimicrobial resistance has been one of the biggest global current issues in medicine and public health. Overuse and imprudent use of antimicrobial agents are recognized as one of the leading causes of antibiotic resistance. The aim of this study was to analyze the attitudesof Polish physicians practicing at the community level towards antibiotics and antimicrobial resistance. The majority of physicians taking part in the survey believed that Polish people overuse antibiotics (98%). Most physicians (91%) considered that antimicrobial resistance is a major problem at present. The majority of physicians indicated the reasons for prescribing the antibiotic are related to health factors, such as optimal recovery (best effectiveness, least side effects) (80%), latest therapeutic guidelines (70%) and microbiological/epidemiological factors (63%). Knowledge of the National Recommendations for the management of Community-Acquired Respiratory Tract Infections 2010(NR-CA-RTI) developed within National Programme for Protection of Antibiotics was declared by 84% of respondents. Among those who are aware of the NR-CA-RTI, the majority follow them in their daily practice (91%). Among physicians, 62% are not familiar with the Centor/McIsaac scores used to differentiate bacterial and viral infections in patients presenting with a sore throat. Among physicians familiar with the scores, 90% use them in their daily practice. Rapid microbiological detection methods for Group A beta-hemolytic streptococcal pharyngitis are used only by 20% of respondents. Almost all of physicians declared readiness to use these tests. Main sources of information on antibiotics prescribing originate from Polish medical journals, scientific conferences organized by medical societies, pharmaceutical companies.
ß-hemolytic, pyogenic Streptococci are classified according to type of major surface antigen into A (Streptococcus pyogenes), B (Streptococcus agalactiae), C (multiple species including Streptococcus dysgalactiae) and G (multiple species including Streptococcus canis) Lancefield groups. Group A Streptococcus causes each year hundreds of thousands deaths globally as a result of infections and post-infectional sequelae. An increasing number of severe, invasive infections is caused by selected, specialized pathogenic clones. Within the last 50 years, an increasing number of human infections caused by groups B, C and G Streptococcus (GBS, GCS, GGS) has been observed worldwide. GBS was first identified as animal pathogen but the spectrum of diseases caused by GBS quickly shifted to human infections. Groups C and G Streptococcus are still regarded mostly as animal pathogens, however, an increased number of severe infections caused by these groups is observed. The increasing number of human infections caused worldwide by GCS/GGS can be a sign of similar development from animal to human pathogen as observed in case of GBS and this group will gain much more clinical interest in the future.The situation in Poland regarding invasive infections caused by pyogenic streptococci is underestimated.
Enterococcus faecalis plays a significant role in hospital-acquired infections (HAIs), and combination of penicillin with aminoglycoside is important in therapy of invasive HAIs. Penicillin resistance in this organism is due to modification of the drug target, penicillin-binding protein (PBP5), its overproduction and expression of β-lactamase. Although rare, this phenotype is often associated with multi-resistant high-risk enterococcal clonal complexes (HiRECCs), such as CC2 and CC9 which may promote its spread in the near future.
Pheromone-responsive plasmids constitute a unique group of ~ 20 plasmids identified, as yet, only among enterococcal species. Several of their representatives, e.g. pAD1, pCF10, pPD1 and pAM373 have been extensively studied. These plasmids posses a sophisticated conjugation mechanism based on response to sex pheromones - small peptides produced by plasmid-free recipient cells. Detailed analysis of regulation and function of the pheromone response process revealed its great complexity and dual role - in plasmid conjugation and modulation of enterococcal virulence. Among other functional modules identified in pheromone plasmids, the stabilization/partition systems play a crucial role in stable maintenance of the plasmid molecule in host bacteria. Among them, the par locus of pAD1 is one of the exceptional RNA addiction systems. Pheromone-responsive plasmids contribute also to enterococcal phenotype being an important vehicle of antibiotic resistance in this genus. Both types of acquired vancomycin resistance determinants, vanA and vanB, as well many other resistant phenotypes, were found to be located on these plasmids. They also encode two basic agents of enterococcal virulence, i.e. aggregation substance (AS) and cytolysin. AS participates in mating-pair formation during conjugation but can also facilitate the adherence of enterococci to human tissues during infection. The second protein, cytolysin, displays hemolytic activity and helps to invade eukaryotic cells. There are still many aspects of the nature of pheromone plasmids that remain unclear and more detailed studies are needed to understand their uniqueness and complexity.
Enterococcus faecalis is an important nosocomial pathogen causing serious invasive infections. One of the virulence factors of this pathogen, gelatinase GelE, is a protease whose gene expression is regulated by the Fsr quorum sensing system. In this study, we used a wellcharacterized collection of 153 clinical E. faecalis isolates to investigate the distribution of genes involved in gelatinase expression. Although 140 isolates (91% of the group) harbored the gelE gene, only 81 isolates (53%) produced active gelatinase. The gelatinase-negative phenotype was found in several unrelated clones, and appeared to be caused by various genetic events. Isolates of the hospital-adapted clonal complex 2 (CC2) and of CC40 were uniformly gelatinase-positive, while all the CC87 isolates contained the 23.9 kb deletion encompassing most of the fsr locus and were gelatinase-negative. No significant differences among isolates of different clinical origin and gelatinase activity or presence of the fsr genes were found with the exception of isolates from cerebrospinal fluid, which were more often gelatinase-positive than colonizing isolates.
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