Marina Dinić

Helicobacter pylori: An Underestimated Factor in Acute Anterior Uveitis and Spondyloarthropathies?

Acute anterior uveitis (AAU) is the most common form of intraocular inflammation, but its aetiology is still unclear. Fifty percent of AAU patients are HLA-B27-positive, and half of these also have spondyloarthropathies (SpA). Numerous serological studies have shown elevated levels of serum antibodies to various Gram-negative bacteria in HLA-B27-positive AAU and SpA patients. Antigenic similarities between these bacteria and host components (HLA-B27) have already been shown. Still, the mechanism underlying these diseases has not been clarified. Among the Gram-negative bacteria, Helicobacter pylori has not been screened in AAU patients. The purpose of our study was to see if this common human pathogen somehow interferes with AAU. In addition Chlamydia trachomatis, Yersinia enterocolitica 03 and 09, Salmonella sp. and Proteus OX19 were also examined. A total of 60 patients consisting of 4 groups (15 patients with AAU, 15 with SpA, 15 with AAU+SpA and 15 healthy control persons) were examined. A high percentage of the serological results of all investigated bacteria was positive: 80% in the AAU, 93.3% in the SpA and 100% in the AAU+SpA group, while it amounted to 66.7% in the control group (p < 0.05). H. pylori showed the highest percentage of positivity in all 3 patient groups (66.7% in the AAU, 73.3% in the SpA and 80% in the AAU+SpA group). In contrast, 26.7% of the controls were anti-H.-pylori-positive, thus showing a statistically significant difference between the patients and the control group (p < 0.05). HLA-B27/B7-CREG positivity was detected in 53.3% of the AAU, 66.7% of the SpA and 93.3% of the AAU+SpA patients and in none of the controls. Our results suggest that H. pylori might be a candidate participating in the development of AAU and SpA. They also support the theory of genetic (HLA-B27) and exogenous factors (Gram-negative bacteria) as probable background of these diseases.

Hepatitis C virus genotypes and the development of hepatocellular carcinoma.

OBJECTIVE:  The aim of this study was to investigate the prevalence of hepatitis C virus (HCV) infection in patients with hepatocellular carcinoma (HCC) in our geographic area, and to determine if there is a correlation between HCV genotypes and the development of HCC.

Correlation between antimicrobial consumption and antimicrobial resistance of Pseudomonas aeruginosa in a hospital setting: a 10-year study.

Antimicrobial resistance is one of the greatest threats to human health. One of the most important factors leading to the emergence of resistant bacteria is overuse of antibiotics. The purpose of this study was to investigate the correlation between antimicrobial usage and bacterial resistance of Pseudomonas aeruginosa (P. aeruginosa) over a 10‐year period in the Clinical Center Niš, one of the biggest tertiary care hospitals in Serbia. We focused on possible relationships between the consumption of carbapenems and beta‐lactam antibiotics and the rates of resistance of P. aeruginosa to carbapenems.

Serum anti-Helicobacter pylori IgA and IgG antibodies in asymptomatic children in Serbia

The aim of this study was to determine the seroprevalence of Helicobacter pylori and the distribution of anti-H.pylori IgA and IgG antibodies in asymptomatic children aged between 7 and 18 y. We studied the serum samples of 283 children using the commercial ELISA test for the detection of anti-H. pylori IgA and IgG antibodies. The overall prevalence of anti-H. pylori antibodies was 36.4%. The seroprevalence was 35%, 28.3%, 37.5%, and 42.2% for the ages of 7, 10, 14 and 18 y, respectively. Serum IgG antibodies alone were detected in 88.3%, IgA alone in 4.9%, and both IgA and IgG antibodies were detected in 6.8% of samples. The mean levels of IgG antibodies to H. pylori increased with age. We concluded that the prevalence of H. pylori antibodies in Serbian children was high (36.4%), ranging from 35% to 42.2%. The detection of IgG antibodies is useful for the determination of seroprevalence in asymptomatic children.

Staphylococcus aureus: Immunopathogenesis and Human Immunity

Summary Considering a large number of pathogen factors that enable high virulence of a microorganism such as Staphylococcus aureus (S. aureus), it is essential to see them through the continuous adaptation to the newly acquired mechanisms of the host immune response and efforts to overcome these, allowing the bacteria a perfect ecological niche for growth, reproduction, and location of new hosts. Past efforts to create a vaccine that would provide effective protection against infections caused by S. aureus remained without success. The reasons for this stem from the outstanding adaptability skills of this microorganism to almost all environmental conditions, the existence of a numerous virulence factors whose mechanisms of action are not well known, as well as insufficient knowledge of the immune response to S. aureus infections. This review article deals with this issue from another perspective and emphasizes actual knowledge on virulence factors and immune response to S. aureus. Sažetak Brojni su faktori patogenosti koji omogućavaju visok stepen virulencije mikroorganizmu poput Staphylococcus aureus (S. aureus). Posebno je važno sagledati faktore sposobnosti stalne adaptacije na mehanizme imunskog odgovora domaćina, što bakteriji omogućava idealnu ekološku nišu za rast, razmnožavanje i širenje. Dosadašnji napori da se dođe do vakcine koja bi omogućila efikasnu zaštitu od infekcija izazvanih S. aureusom ostali su bez uspeha. Razlozi za ovakvu situaciju se nalaze u izraženoj adaptaciji ovog mikroorganizma na gotovo sve uslove spoljašnje sredine, u postojanju velikog broja faktora virulencije čiji mehanizmi delovanja nisu dovoljno poznati, kao i nedovoljnog poznavanja imunskog odgovora na infekciju S. aureus. Svrha ovog rada je da se sa novijih aspekata sagleda navedena problematika i istaknu savremena saznanja o faktorima virulencije i imunskom odgovoru na S. aureusu.

Nasal Carriage of Staphylococcus aureus in Healthy Adults and in School Children

Summary Staphylococcus aureus (S. aureus) is a microorganism that colonizes the skin and mucosal surfaces of healthy individuals, but it is also one of the most common causes of community-acquired and hospital infections. Nasal carriage of S. aureus represents a major risk factor for the development of infection with this bacterium. A special therapeutic problem are methicillin-resistant isolates of S. aureus (MRSA). The aim of this study was to assess the nasal carriage of S. aureus in healthy individuals in the local community, and the sensitivity of the microorganism to antibiotics. The study enrolled 56.868 healthy individuals aged 19 to 65 years, and 2.040 healthy school children aged 15 to 19 years. Specimens to be studied were obtained from anterior nares. We used the disk diffusion method (Kirby-Bauer) on Mueller- Hinton agar to assess the sensitivity of isolated S. aureus. S. aureus was isolated in 1.381 (2.34%) respondents. Positive findings were obtained in 2.33% of adult examinees, and in 2.59% of studied school children. We found a low level of susceptibility only to penicillin (5.36%). The susceptibility of S. aureus isolates to all other tested antibiotics was present in a high percentage, with the lowest percentage of susceptibility to doxycycline (71.54%) and erythromycin (86.09%). The highest percentage of susceptibility of tested isolates was reported for fusidic acid (99.27%). In relation to the total number of S. aureus isolates from nasal swabs in adults, MRSA was present in 8.96% (119 isolates), while there were 4 MRSA isolates from nasal swabs in school children. In this study, we established a low percentage of nasal carriage of S. aureus in the population of healthy individuals, but a high percentage of MRSA. Sažetak Staphylococcus aureus (S. aureus) je mikroorganizam koji kolonizuje kožu i sluzokože zdravih osoba ali i jedan od najčešćih uzročnika vanbolničkih i bolničkih infekcija. Kolonizacija sluzokože nosa S.aureusom predstavlja glavni faktor rizika za razvoj infekcija ovom bakterijom. Poseban terapijski problem predstavljaju meticilin-rezistentni sojevi S. aureus (MRSA). Cilj ovog istraživanja bio je utvrđivanje kolonizacije sluzokože nosa S. aureus-om u zdravoj populaciji u lokalnoj sredini i njihove osetljivosti prema antibioticima. Istraživanjem je obuhvaćeno 56 868 zdravih odraslih osoba starosti od 19 do 65 godina i 2 040 zdrave školske dece uzrasta od 15 do 19 godina kod kojih su uzorkovani brisevi sluzokože nosa. Ispitivanje osetljivosti izolovanih sojeva S. aureus izvršeno je disk difuzionom metodom (Kirby-Bauer) na Mueller- Hintonovom agaru. S. aureus je izolovan kod 1381 ispitanika ili 2,34%. Pozitivan nalaz dobijen je kod 2,33% odraslih ispitanika i kod 2,59% ispitivane školske dece. Nizak nivo osetljivosti detektovan samo prema penicilinu (5,36%). Osetljivost S. aureus izolata prisutna je u visokom procentu prema ostalim testiranim antibioticima, sa najmanjim procentom osetljivih izolata prema doksiciklinu (71,54%) i eritromicinu (86,09%). Najveći procenat osetljivosti ispitivanih izolata je prema fusidinskoj kiselini (99,27%). U odnosu na ukupan broj izolata S. aureus izolovanih iz briseva odraslih osoba MRSA je zastupljen sa 8,96% (119 izolata), dok je iz briseva školske dece izolovano samo 4 MRSA izolata. Ovim istraživanjem utvrdili smo da je kliconoštvo S. aureus u populaciji zdravih osoba zastupljeno u malom procentu, ali je visok procenat zastupljenosti MRSA.

Helicobacter Pylori Infection and Upper Gastrointestinal Disease

Helicobacter Pylori Infection and Upper Gastrointestinal Disease Helicobacter pylori infection is one of the most common bacterial infections in humans, being present in over a half of the world population. Helicobacter pylori infection, by itself, does not necessarily produce the symptoms of gastrointestinal tract diseases, but certainly presents a risk for their development. The clinical outcome of Helicobacter pylori infection depends on the interaction of numerous factors: the virulence of a bacterial strain, genetic predisposition and premorbid host conditions, as well as the environmental factors. Accordingly, a diagnosis of Helicobacter pylori infection will be of clinical relevance only if it is necessary to establish the cause of a disease associated with this infection. Thus, a thorough knowledge of the diseases associated with Helicobacter pylori infection is a key factor in any relevant assessment of the need for eradication therapy. Helicobacter pylori infekcija i oboljenja gornjeg gastrointestinalnog trakta Helicobacter pylori infekcija je jedna od najčešćih bakterijskih infekcija kod ljudi i prisutna je kod preko polovine svetske populacije. Helicobacter pylori infekcija sama po sebi ne dovodi uvek do pojave simptoma oboljenja gastrointestinalnog trakta ali predstavlja rizik za njihov razvoj. Klinički ishod Helicobacter pylori infekcije zavisi od interakcije brojnih faktora: virulencije bakterijskog soja, genetske predispozicije i premorbidnog stanja domaćina, faktora životne sredine. Dijagnoza Helicobacter pylori infekcije imaće klinički značaj samo ukoliko je potrebno naći uzrok nekog od oboljenja povezanih sa ovom infekcijom. Poznavanje oboljenja povezanih sa Helicobacter infekcijom predstavlja ključni faktor pri adekvatnoj proceni potrebe za primenom eradikacione terapije.

Resistance in Staphylococcus Aureus: The Never-Ending Story

Summary Combating Staphylococcus aureus (S. aureus) infections using antibacterial drugs is actually an ongoing effort to overcome resistance mechanism of this microorganism. In this paper, we discussed (1) the mechanisms of resistance to some of the most commonly used antimicrobial agents in the treatment of S. aureus: methicillin, vancomicyn and quinolones. In addition, (2) efflux pump mechanisms involved in maintaining homeostasis in the presence of compounds that inhibit S. aureus growth and reproduction, as well as mechanisms of resistance to a number of antibiotics, have been reviewed.