Eradikacija Helicobacter pylori kod bolesnika bez gastričkih simptoma koji imaju rekurentni aftozni stomatitis - pilot studija

Background/Aim. Helicobacter (H.) pylori is a widespread bacterium and its involvement in pathogenesis of gastric diseases is well-known. However, H. pylori role in etiology of other histologically similar conditions, especially recurrent aphthous stomatitis (RAS) is still controversial. Research regarding H. pylori and its association with RAS, as well as the treatment options were always conducted on patients with diagnosed gastric problems. The aim of this study was to determine whether H. pylori is present in the oral cavity of patients suffering from RAS but without any symptoms or medical history of gastric disease. Methods. A total of 15 patients with RAS participated in the study. None of the participants suffered from any gastrointestinal disorders. Two dental plaque samples from each participant were collected. The first was analyzed using rapid urease test and the second one was put in transport medium and sent for cultivation. The sensitivity of H. pylori to antibiotics was established using disk diffusion method of sensitivity testing for every patient individually and adequate therapy was prescribed. Results. Before the treatment the mean annual recurrence rate of RAS was 8.1 ± 2.1, with the average number of lesions being 3.9 ± 1.9. During the 12-month observation period after the eradication therapy, none of the patients reported recurrence of aphthous lesions. The treatment was successful in all cases. Conclusion. This study shows that RAS can be effectively treated by successful eradication of oral H. pylori, and that RAS could be possibly considered as an early warning sign of potential gastric infection by H. pilory.Uvod/Cilj. Helicobacter (H.) pylori je široko rasprostanjena bakterija i njen uticaj na nastanak gastričkih oboljenja vrlo dobro je dokumentovan. Međutim, uloga H. pylori u patogenezi histološki sličnih oboljenja, posebno rekurentnog aftoznog stomatitisa (RAS), nije dovoljno istražena. Dosadašnje studije, u kojima je ispitivana veza između H. pylori i RAS, kao i moguće terapijske opcije, bile su usmerene ka bolesnicima sa prethodno dijagnostikovanim gastričkim smetnjama. Cilj ovog istraživanja bio je da se utvrdi da li je H. pylori prisutan u usnoj duplji i kod bolesnika bez simptoma i istorije gastričkih oboljenja koji pate od RAS. Metode. U studiji je učestvovalo 15 bolesnika koji pate od RAS. Bolesnici nisu imali smetnje vezane za gornji deo digestivnog trakta. Po dva uzorka dentalnog plaka prikupljena su od svakog bolesnika. Jedan plak je ispitivan uz pomoć brzog ureaza testa, dok je drugi stavljen u transportni medijum i poslat na kultivaciju. Osetljivost H. pylori na antibiotike određivana je uz pomoć antibiograma za svakog bolesnika posebno i, u skladu sa rezultatima, prepisivana je odgovarajuća terapija. Rezultati. Pre lečenja prosečan broj epizoda RAS tokom godine iznosio je 8,1 ± 2,1, sa prosečno 3,9 ± 1,9 aftoznih lezija. Tokom 12-mesečnog perioda nakon eradikacione terapije, ni kod jednog bolesnika nije došlo do ponovne pojave afti. Terapija je bila uspešna kod svih bolesnika. Zaključak. Rezultati ovog istraživanja pokazuju da se RAS može uspešno lečiti eradikacijom H. pylori i da se sama pojava RAS može posmatrati kao rano upozorenje na moguću gastričku infekciju

Adherence and Biofilm Production of Streptococcus pyogenes

Streptococcus pyogenes (group A streptococcus – GAS) can cause numerous human infections, varying from mild skin infections to life‐threatening, e.g. necrotizing fasciitis. Adherence and biofilm production are important in streptoccocal pathogenesis. GAS adhesins are numerous and diverse, with the ability to bind to several different receptors at the same time, which leads to difficulties in their precise identification and classification. Biofilm production is one of the most probable explanation for therapeutic failure in the treatment of GAS infections. Most researchers agreed that biofilm formation is a trait of individual strains rather than a general serotype attribute. The aim of our study is to investigate differences in adherence to laminin and biofilm production between invasive and non‐invasive isolates (NI) of GAS. In this study the correlation between adherence to laminin and invasiveness in GAS isolates is noticed. The strains isolated from GAS carriers and highly invasive (HI) GAS strains have excellent capacity for binding to laminin. When testing biofilm production, there was noticeable positive correlation between adherence and biofilm production among non‐invasive isolates. Non‐invasive isolates were stable biofilm productors. There was no correlation between adherence and biofilm production among invasive isolates. Invasive isolates were also unstable biofilm productors

Antimicrobial Susceptibility Testing: A Comprehensive Review of Currently Used Methods

Antimicrobial resistance (AMR) has emerged as a major threat to public health globally. Accurate and rapid detection of resistance to antimicrobial drugs, and subsequent appropriate antimicrobial treatment, combined with antimicrobial stewardship, are essential for controlling the emergence and spread of AMR. This article reviews common antimicrobial susceptibility testing (AST) methods and relevant issues concerning the advantages and disadvantages of each method. Although accurate, classic technologies used in clinical microbiology to profile antimicrobial susceptibility are time-consuming and relatively expensive. As a result, physicians often prescribe empirical antimicrobial therapies and broad-spectrum antibiotics. Although recently developed AST systems have shown advantages over traditional methods in terms of testing speed and the potential for providing a deeper insight into resistance mechanisms, extensive validation is required to translate these methodologies to clinical practice. With a continuous increase in antimicrobial resistance, additional efforts are needed to develop innovative, rapid, accurate, and portable diagnostic tools for AST. The wide implementation of novel devices would enable the identification of the optimal treatment approaches and the surveillance of antibiotic resistance in health, agriculture, and the environment, allowing monitoring and better tackling the emergence of AMR

The first nationwide multicenter study ofAcinetobacter baumanniirecovered in Serbia: emergence of OXA-72, OXA-23 and NDM-1-producing isolates

Background The worldwide emergence and clonal spread of carbapenem-resistantAcinetobacter baumannii(CRAB) is of great concern. The aim of this nationwide study was to investigate the prevalence of CRAB isolates in Serbia and to characterize underlying resistance mechanisms and their genetic relatedness. Methods Non-redundant clinical samples obtained from hospitalized patients throughout Serbia were included in the prospective, observational, multicenter study conducted from January to June 2018. Samples were initially screened for the presence ofAcinetobacter baumannii-calcoaceticus(Acb) complex using conventional bacteriological techniques. Acb complexes recovered from clinical samples obtained from inpatients with confirmed bacterial infections were further evaluated for the presence ofA. baumannii. Identification to the species level was done by the detection of thebla(OXA-51)gene andrpoBgene sequence analysis. Susceptibility testing was done by disk diffusion and broth microdilution method. CRAB isolates were tested for the presence of acquired carbapenemases(bla(OXA-24-like),bla(OXA-23-like,)bla(OXA-58-like),bla(OXA-143-like),bla(IMP),bla(VIM),bla(GIM),bla(SPM),bla(SIM),bla(NDM)) by PCR. Clonal relatedness was assessed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Results Acb complex was isolated in 280 out of 2401 clinical samples (11.6%). Overall,A. baumanniiwas identified in 237 out of 280 Acb complex (84.6%). CRAB prevalence was found to be 93.7% (237/222). The MIC50/MIC(90)for imipenem and meropenem were 8/ gt 32 mu g/mL and 16/ gt 32 mu g/mL, respectively. Although susceptibility was high for colistin (95.7%;n = 227) and tigecycline (75.1%;n = 178), ten isolates (4.3%) were classified as pandrug-resistant. The following carbapenemases-encoding genes were found: 98 (44.2%)bla(OXA-24-like), 76 (34.5%)bla(OXA-23-like), and 7 (3.2%)bla(NDM-1). PFGE analysis revealed six different clusters. MLST analysis identified three STs: ST2 (n = 13), ST492 (n = 14), and ST636 (n = 10). Obtained results evaluated that circulating CRAB clones in Serbia were as follows:bla(OXA66)/bla(OXA23)/ST2 (32.4%),bla(OXA66)/bla(OXA23)/bla(OXA72)/ST2 (2.7%),bla(OXA66)/bla(OXA72)/ST492 (37.8%), andbla(OXA66)/bla(OXA72)/ST636 (27.1%). Conclusion This study revealed extremely high proportions of carbapenem resistance amongA. baumanniiclinical isolates due to the emergence ofbla(OXA-72),bla(OXA-23), andbla(NDM-1)genes among CRAB isolates in Serbia and their clonal propagation

Yersinia enterocolitica in the pig meat: A risk for food safety

Evropska agencija za bezbednost hrane (EFSA - European Food Safety Authority) objavila je u 2011. godini preporuke za inspekciju trupova svinja. Preporuke se odnose na najznačajnije biološke opasnosti po zdravlje ljudi koje se mogu naći u mesu. Pored Salmonella spp., Toxoplasma gondii i Trichinella spp., kao biološka opasnost navodi se i Yersinia enterocolitica. Yersinia enterocolitica, kao i druge bakterije iz familije Enterobacteriaceae, ima sposobnost opstanka u spoljašnjoj sredini, u koju dospeva preko inficiranih životinja. U Evropi, svinje su najčešći asimptomatski nosioci patogenih sojeva Y. enterocolitica za ljude, posebno soja biotipa 4 (serotipa O:3) i ne tako učestalog biotipa 2 (serotip O:9 i O:27). Uzročnici su najčešće lokalizovani u oralnoj duplji, posebno u tonzilama, submaksilarnim limfnim čvorovima, crevima i fecesu svinja. Pravilan postupak sa trupovima svinja, nakon klanja, može znatno da smanji nivo kontaminacije mesa svinja. Učestalost Y. enterocolitica kod svinja, kao rezervoara ovog patogena, veoma varira. Slučajevi jersinioze kod ljudi zabeleženi su, kako u Evropi, tako i u Japanu, SAD, Nigeriji i Brazilu.The European Food Safety Authority (EFSA - European Food Safety Authority) published in 2011. the recommendations of the inspection of carcasses of pigs. Recommendations are related to the most significant biological hazards to human health that can be found in meat. In addition to Salmonella spp., Toxoplasma gondii and Trichinella spp., as a biological hazard states and Yersinia enterocolitica. Yersinia enterocolitica, and other bacteria of the Enterobacteriaceae family having ability to survive in the environment, in which accrues through the infected animals. In Europe, pigs are the most common asymptomatic carriers of pathogenic strains of Y. enterocolitica to humans, especially biotype 4 (serotype O: 3) and not so frequent biotype 2 (serotype O: 9 and O: 27). The causes are usually localized in the oral cavity, especially in the tonsils, submaxillary lymph nodes, intestines and feces of pigs. The proper treatment of pig carcasses after slaughter, can significantly reduce the level of contamination of pig meat. The incidence of Y. enterocolitica in pigs, as reservoirs of this pathogen varies. Yersiniosis cases in humans have been reported, both in Europe and in Japan, the United States, Nigeria and Brazil

Characterization of macrolide-resistant non-invasive pneumococci in the pre-vaccine era in Serbia

Numerous reports have confirmed that increased macrolide use in the treatment of respiratory tract infection has contributed to the emergence of antibiotic resistance worldwide. Studies have also shown that pneumococcal vaccine can reduce pneumococcal resistance. The aim of this study was to determine the prevalence of co-resistance to penicillin and other antibiotics in macrolide-resistant (MR) non-invasive pneumococcal isolates and to evaluate serotype distribution in resistant strains in the pre-vaccine era in Serbia. About 80% of MR isolates expressed the MLS phenotype with very high resistance to both erythromycin and clindamycin. A total of 132 (84.1%) MR isolates were multiresistant, i.e., they were resistant to erythromycin, penicillin, tetracycline, and trimethoprim–sulfamethoxazole. Among 157 MR pneumococci, 11 different serotypes were found. Four serotypes, 19F, 14, 6B, and 23F, accounted for 77.7% of all MR pneumococcal isolates. Among isolates with the cMLS phenotype, serotypes 19F and 14 were predominant, whereas serotype 6A was the most common among those with the M phenotype, followed by 14. In conclusion, co-resistance to macrolides and penicillin in our non-invasive pneumococcal isolates is high. The majority of tested strains (∼80%) belonged to the four serotypes (19F, 14, 6B, and 23F) that are included in all conjugate vaccine formulations

Influence of subinhibitory antibiotic concentration on Streptococcus pyogenes adherence and biofilm production

In this study, the focus was on the effects of sub-MICs of the antibiotics on adherence, hydrophobicity, and biofilm formation by two groups of Streptococcus pyogenes strains, which were responsible for different clinical cases. The aim of this study was to explore the effects of sub-MICs of penicillin, ceftriaxone, erythromycin, and clindamycin on adherence, surface hydrophobicity, and biofilm biomass in two selected collections of group A streptococcus (GAS): strains isolated from carriers (CA) and strains isolated from patients with tonsillopharyngitis (TPh). Isolates were tested for hydrophobicity to xylene, adherence, and biofilm production in uncoated microtiter plates before and after treatment with 1/2 and 1/4 MICs of antibiotics. Penicillin reduced adherence and biofilm production in TPh strains, whereas ceftriaxone diminished adherence and biofilm formation in CA group. On the contrary, clindamycin enhanced adherence and biofilm production in both groups of strains. Erythromycin did not significantly alter adherence, but triggered biofilm production in both groups of isolates. Hydrophobicity of both groups of strains was significantly reduced after exposure to all antibiotics. Beta-lactams displayed anti-biofilm activity; penicillin diminished both adherence and biofilm production in TPh strains, whereas ceftriaxone reduced it in strains isolated from CA

Serotype distribution, antimicrobial susceptibility and molecular epidemiology of invasive Streptococcus pneumoniae in the nine-year period in Serbia

Streptococcus pneumoniae is one of the leading bacterial pathogens that can cause severe invasive diseases. The aim of the study was to characterize invasive isolates of S. pneumoniae obtained during the nine-year period in Serbia before the introduction of the pneumococcal conjugate vaccines (PCVs) into routine vaccination programs by determining: serotype distribution, the prevalence and genetic basis of antimicrobial resistance, and genetic relatedness of the circulating pneumococcal clones. A total of 490 invasive S. pneumoniae isolates were included in this study. The serotype, antimicrobial susceptibility, and ST of the strains were determined by the Quellung reaction, disk- and gradient-diffusion methods, and multilocus sequence typing (MLST), respectively. The most common serotypes in this study were 3, 19F, 14, 6B, 6A, 19A, and 23F. The serotype coverages of PCV10 and PCV13 in children less than 2 years were 71.3 and 86.1%, respectively, while PPV23 coverage in adults was in the range of 85-96%, depending on the age group. Penicillin and ceftriaxone-non-susceptible isolates account for 47.6 and 16.5% of all isolates, respectively. Macrolide non-susceptibility was detected in 40.4% of isolates, while the rate of multidrug- and extensive-drug resistance was 20.0 and 16.9%, respectively. The MLST analysis of 158 pneumococci identified 60 different STs belonging to the 16 Clonal Complexes (CCs) (consisting of 42 STs) and 18 singletons. The most common CC/ST were ST1377, CC320, CC15, CC273, CC156, CC473, CC81, and CC180. Results obtained in this study indicate that the pre-vaccine pneumococcal population in Serbia is characterized by high penicillin and macrolides non-susceptibility, worrisome rates of MDR and XDR, as well as a high degree of genetic diversity. These findings provide a basis for further investigation of the changes in serotypes and genotypes that can be expected after the routine introduction of PCVs