Aleksandra Petrović

Antimicrobial activity of Eucalyptus camaldulensis essential oils and their interactions with conventional antimicrobial agents against multi-drug resistant Acinetobacter baumannii.

ETHNOPHARMACOLOGICAL RELEVANCE Traditional herbal medicine has become an important issue on the global scale during the past decade. Among drugs of natural origin, special place belongs to essential oils, known as strong antimicrobial agents that can be used to combat antibiotic-resistant bacteria. Eucalyptus camaldulensis leaves are traditional herbal remedy used for various purposes, including treatment of infections. The aim of this study was to determine antimicrobial potential of two E. camaldulensis essential oils against multi-drug resistant (MDR) Acinetobacter baumannii wound isolates and to examine possible interactions of essential oils with conventional antimicrobial agents. MATERIALS AND METHODS Chemical composition of essential oils was determined by gas chromatography-mass spectrometry analysis (GC-MS). MIC values of essential oils against A. baumannii strains were estimated by modified broth microdilution method. The components responsible for antimicrobial activity were detected by bioautographic analysis. The potential synergy between the essential oils and antibiotics (ciprofloxacin, gentamicin and polymyxin B) was examined by checkerboard method and time kill curve. RESULTS The dominant components of both essential oils were spatulenol, cryptone, p-cimene, 1,8-cineole, terpinen-4-ol and β-pinene. The detected MICs for the E. camaldulensis essential oils were in range from 0.5 to 2 μl mL(-1). The bioautographic assay confirmed antibacterial activity of polar terpene compounds. In combination with conventional antibiotics (ciprofloxacin, gentamicin and polymyxin B), the examined essential oils showed synergistic antibacterial effect in most of the cases, while in some even re-sensitized MDR A. baumannii strains. The synergistic interaction was confirmed by time-kill curves for E. camaldulensis essential oil and polymyxin B combination which reduced bacterial count under detection limit very fast, i.e. after 6h of incubation. CONCLUSIONS The detected anti-A. baumannii activity of E. camaldulensis essential oils justifies traditional use of this plant. The proven E. camaldulensis essential oil synergistic interactions with conventional antibiotics could lead to the development of new treatment strategies of infections caused by MDR A. baumannii strains in the term of antibiotic dose reduction.

Molecular detection of emerging tick-borne pathogens in Vojvodina, Serbia

Ticks play an important role in disease transmission globally due to their capability to serve as vectors for human and animal pathogens. The Republic of Serbia is an endemic area for a large number of tick-borne diseases. However, current knowledge on these diseases in Serbia is limited. The aim of this study was to investigate the presence of new emerging tick-borne pathogens in ticks collected from dogs and the vegetation from different parts of Vojvodina, Serbia. A total of 187 ticks, including 124 Rhipicephalus sanguineus, 45 Ixodes ricinus and 18 Dermacentor reticulatus were collected from dogs. In addition, 26 questing I. ricinus ticks were collected from the vegetation, using the flagging method, from 4 different localities in Vojvodina, Serbia. DNA was extracted from each tick individually and samples were tested by either conventional or real-time PCR assays for the presence of Rickettsia spp.-DNA (gltA and ompA gene fragments), Ehrlichia/Anaplasma spp.-DNA (16S rRNA gene fragment) and Hepatozoon spp./Babesia spp.-DNA (18S rRNA gene fragment). In addition, all I. ricinus DNA samples were tested for Bartonella spp.-DNA (ITS locus) by real-time PCR. In this study, the presence of novel emerging tick-borne pathogens including Rickettsia raoultii, Rickettsia massiliae, Babesia venatorum, Babesia microti, Hepatozoon canis and Candidatus Neoehrlichia mikurensis was identified for the first time in Serbia. Our findings also confirmed the presence of Rickettsia monacensis, Babesia canis and Anaplasma phagocytophilum in ticks from Serbia. The findings of the current study highlight the great diversity of tick-borne pathogens of human and animal importance in Serbia. Physicians, public health workers and veterinarians should increase alertness to the presence of these tick-borne pathogens in this country.

The application of lambda-cyhalothrin in tick control

In recent years, in urban areas of Novi Sad, unique ecological conditions, specific floristic and faunistic composition and poor habits of citizens in sense of public health, facilitate the development and maintenance of ticks. Regarding the importance of ticks as vectors of severe human and animal diseases, complex and detailed studies are conducted with an aim to find the most efficient methods for tick control. Two tick species, Ixodes ricinus and Dermacentor marginatus, were identified during a 3-year period on the territory of Municipality of Novi Sad. During 2006, the efficacy of the pyrethroid lambda-cyhalothrin in tick control varied from 60.7 to 100%. The highest efficacy recorded in 2007 was 92.3%. The efficacy of lambda-cyhalothrin in 2008 varied from 39.1 to 100%. Lambda-cyhalothrin showed high efficacy in tick control at localities which were improved before the application (mowed, litter removed, abundance control and euthanasia of abandoned cats and dogs). The results of this research indicate that lambda-cyhalothrin has a toxic effect on ticks and could be used as efficient acaricide for tick control, although its efficacy depends on formulation, terrain features and methods of application.

Contact Sensitivity in Patients with Psoriasis in Vojvodina

Background: Immunologic studies indicate that psoriasis may represent an organ-integrated response. Objective: We assessed contact hypersensitivity in plaque-type psoriasis, its frequency, etiology and association with severity of psoriasis. Methods: Contact hypersensitivity was defined as a positive patch test (PT) to at least one of 44 ubiquitous contact allergens. Patients with exclusively plaque psoriasis and control groups (patients with allergic contact or extrinsic atopic dermatitis and healthy persons) were tested with the European standard series; plant-related standard allergens; Compositae allergens, and our own extracts from Compositae plants ubiquitous in Vojvodina. Sensitization rates to allergens were standardized for age and sex, and rates in women and in men were both standardized for age. Disease severity was evaluated using the Psoriasis Area Severity Index score. Results: 15,123 PTs were performed. Among psoriatic patients in Vojvodina, the overall rate of sensitivity, standardized for age and sex, was 18.9%. Rates in women (27.7%) and men (5.8%), both standardized for age, were significantly different. Male psoriatic patients reacted less than healthy males, the difference being on the margin of significance. There was no relationship between severity of disease and PT reactivity. Yarrow extract, nickel and a Compositae mix were the most common allergens that produced positive reactions. Conclusion: Although patch testing in psoriatic patients can be quite challenging, time-consuming and difficult, it will provide further insight into the pathophysiology of psoriasis. Factors other than different exposure to allergens may also be responsible for a sex-related difference in contact sensitivity. Future studies should focus on this field.

Molecular characterization of Borrelia strains isolated from ticks in Vojvodina

Borrelia burgdorferi sensu lato (s.l.) complex represents a group of different types of spirochete that are present globally, which causes Lyme borreliosis. The total number of types is still not final because new genetic and antigenic isolates are still being described. The clinical picture of Lyme borreliosis in people is polymorphic and is characterized with symptoms similar to flu syndromes together with erythema migrans, rheumatologic, cardiologic and neurological complications. Apart from people, dogs, horses, bovines and sheep can suffer from Lyme borreliosis. In Europe, the most important vector transmitting Lyme disease is the tick Ixodes ricinus. A description of different species of Borrelia in ticks has opened a completely new field of investigating the ecology of Lyme borreliosis. It is especially important to investigate a connection between different types of Borrelia, ticks as vectors and vertebrates as the reservoirs on various geographical localities. The aim of the work is to isolate Borrelia species from the collected ticks I. ricinus from the geographical territory of Vojvodina, and to do a molecular characterization of the isolated strains of Borrelia. A total of 12 tick pools of the type I. ricinus were cultivated in Barbour-Stoenner-Kelly-H medium with additional antibiotics and subcultivated into a modified Kelly-Pettenkofer/Preac-Mursic medium, until a clear culture is reached. For the molecular characterization of isolated strains of Borrelia, molecular methods MluI-LRFP and real-time PCR for hbb gene were used. In this research, out of 12 pools of ticks species I. ricinus 3 strains of Borrelia from the B. burgdorferi s.l. complex were isolated. All three isolates of Borrelia from ticks of the tick species I. ricinus from the territory of Vojvodina were identified as Borrelia afzelii by applying molecular methods (MluI-LRFP and real-time PCR for hbb gene). By applying MluI-LRFP all three isolated strains of B. afzelii were characterized as a subtype Mlal. In this research, like in the previous researches, we have not proved the presence of a pathogenic species Borrelia spielmanii in ticks of the species I. ricinus.

Seasonal distribution and species association among spider mites (Acari: Tetranychidae) and predatory mites (Acari: Phytoseiidae and Acari: Stigmaeidae) in Serbian apple orchards

ABSTRACT Species composition and population dynamics of spider mites (Panonychus ulmi (Acari: Tetranychidae) (Koch) and Tetranychus urticae Koch (Acari: Tetranychidae)) and predaceous mites (Amblyseius andersoni (Chant) (Acari: Phytoseiidae) and Zetzellia mali (Ewing) (Acari: Stigmaeidae)) were studied for eight months each year (March–October) during 2005–2007 at two localities with different intensities of pesticide use. Using Berger–Parkers dominance index and Sorensons coefficient, the index of dominance and predator–predator, predator–prey, and prey–prey associations were defined among each of these species to determine changes in species compositions and population densities and comprehend the influence of pesticide use in pest management on populations of spider and predatory mites in apple orchards. Sorensons coefficient helped to measure the intensity of positive, neutral, or negative interspecific associations for each species and Berger–Parkers dominance index clarified the dominance of specific species. During 2005 the dominant species in both localities was P. ulmi, but during 2006–2007 at one locality both species of spider mites showed almost equal dominance. The results of Sorensons coefficient confirmed that there was significant predator–prey association among P. ulmi and A. andersoni and P. ulmi and Z. mali, and prey–prey association between P. ulmi and T. urticae in both localities. The analysis of the population dynamics showed delayed occurrence of predatory mites compared with the spider mites, from 48 to 106 days for A. andersoni and 91 to 137 days for Z. mali depending on the research period and locality.

Indolent Systemic Mastocytosis – a Case Report

Abstract Indolent systemic mastocytosis is a benign form of systemic mastocytosis characterized by an abnormal proliferation of mast cells either in the bone marrow or in numerous tissues. Case Report: A 27-year-old female patient was admitted to our department due to urticaria which started a month ago. Before the skin changes appeared, our patient suffered from a toothache, so she took various painkillers (nimesulide, ibuprofen, acetylsalicylic acid, paracetamol). During skin examination, individual hyperpigmented macules on the trunk and lower limbs were observed as incidental findings. The patient reported having them for the last two years. Dariers sign was positive. Following the examination, she was admitted due to suspected urticaria pigmentosa. Laboratory Findings: erythrocyte sedimentation rate: 9 mm/h; complete blood count, urine, blood glucose, total and direct bilirubin, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, urea, creatinine, and uric acid were within normal ranges. Electrolytes: sodium, potassium, chlorine clearance, total calcium and calcium ionized, osteocalcin, and crosslaps were within normal ranges as well. Fibrinogen: 5.57 g/l; 5-Hydroxyindoleacetic acid: 49.8 umol/dU (10.4 - 31.2). Bone densitometry, chest x-ray and upper abdomen ultrasound findings were normal. The suspected clinical diagnosis of urticaria pigmentosa was confirmed by skin biopsy. Histopathological examination of the bone marrow showed moderately increased cellularity (60 - 70%). All three types of blood cells were slightly multiplied. Focal infiltrations were found in the perivascular area, consisting of elongated, oval cells with abundant eosinophilic granular cytoplasm. The nuclei were regular, oval shaped with finely granular chromatin and inconspicuous nucleoli. No nuclear atypia was found. These cells are highly CD117-positive. This finding strongly indicated bone marrow infiltration in systemic mastocytosis. The diagnosis was based on ‘major’ and ‘minor’ diagnostic criteria. The recommended therapy included H1 and H2 antagonists and topical corticosteroids. Conclusion: Regular follow-up was recommended in order to prevent complications and malignant alterations.