Natasa Opavski
University of Belgrade
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Featured researches published by Natasa Opavski.
Infection, Genetics and Evolution | 2015
Natasa Opavski; Ina Gajic; Anna L. Borek; Katarzyna Obszańska; Maja Stanojevic; Ivana Lazarevic; Lazar Ranin; Izabela Sitkiewicz; Vera Mijac
A steady increase in macrolide resistance in Streptococcus pyogenes, group A streptococci (GAS) was reported in Serbia during 2004-2009 (9.9%). However, there are no data on the molecular epidemiology of pharyngeal macrolide resistance GAS (MRGAS) isolates. Therefore, the aims of this first nationwide study were to examine the prevalence of macrolide resistance in Serbian GAS and to determine their resistance phenotypes, genotypes and clonal relationships. Overall 3893 non-duplicate pharyngeal S. pyogenes isolates from outpatients with GAS infection were collected throughout country during 2008 and 2009. Among 486 macrolide resistant pharyngeal isolates collected, 103 were further characterized. Macrolide resistance phenotypes and genotypes were determined by double-disk diffusion test and PCR, respectively. Strain relatedness was determined by emm typing, multilocus sequence typing (MLST), multilocus variable tandem repeat analysis (MLVA), phage profiling (PP) and virulence factor profiling (VFP). Overall, macrolide resistance among GAS isolates in Serbia was 12.5%. M phenotype was the most common (71.8%), followed by iMLS (18.4%) and cMLS (9.7%). Three clonal complexes--emm75/mefA/ST49, emm12/mefA/ST36 and emm77/ermA/tetO/ST63 comprised over 90% of the tested strains. Although MLVA, PP and VFP distinguished 10, 20 and 12 different patterns, respectively, cluster analysis disclosed only small differences between strains which belonged to the same emm/ST type. Our data indicate dominance of three major internationally widely disseminated macrolide resistant clones and a high genetic homogeneity among the Serbian MRGAS population. Continued surveillance of macrolide resistance and clonal composition in MRGAS in Serbia in future is necessary to determine stability of MRGAS clones and to guide therapy strategies.
Clinical Microbiology and Infection | 2010
Vera Mijac; Lazar Ranin; M. Marković; C. Heeg; Ralf René Reinert; Natasa Opavski
This is the first study concerning the molecular epidemiology of group A streptococcus in Serbia and includes 145 isolates from patients with various infections during the period 2001-2007. The emm types, superantigen profile and susceptibility pattern were determined. Among 31 emm types identified, the most prevalent were emm 6, emm 12, emm 1, and emm 58. All isolates showed uniform antimicrobial susceptibility to all tested antibiotics, with the exception of tetracycline and erythromycin (41% and 0.7% resistant strains, respectively). Significant heterogeneity of emm types was found, with a high frequency of emm 6 and emm 58, as well as a considerable prevalence of tetracycline resistance, and a low level of macrolide resistance.
International Journal of Medical Microbiology | 2018
Ina Gajic; Céline Plainvert; Dusan Kekic; Nicolas Dmytruk; Vera Mijac; Asmaa Tazi; Philippe Glaser; Lazar Ranin; Claire Poyart; Natasa Opavski
Streptococcus agalactiae (group B Streptococcus, GBS) remains the leading cause of invasive diseases in neonates and an important cause of infections in the elderly. The aim of this study was to access the prevalence of GBS genito-rectal colonisation of pregnant women and to evaluate the genetic characteristics of invasive and non-invasive GBS isolates recovered throughout Serbia. A total of 432 GBS isolates were tested for antimicrobial susceptibility, capsular polysaccharide (CPS) types and the presence of the hvgA gene. One hundred one randomly selected isolates were further characterized by clustered regularly interspaced short palindromic repeats (CRISPRs) analysis and/or multilocus sequence typing (MLST). The prevalence of GBS colonization in pregnant women was 15%. Overall, six capsular types (Ia, Ib, II to V) were identified, the most common being III (32.2%) and V (25.2%). The hiper-virulent clone type III/ST17 was present in 43.1% and 6.3% (p < 0.05) of paediatric and adults isolates, respectively. Comparative sequence analysis of the CRISPR1 spacers content indicated that a few clones comprised the vast majority of the tested GBS isolates. Thus, it was estimated that dominant clones recovered from infants were CPS III/ST17 in late-onset infections (19/23; 82.6%), and Ia/ST23 in early-onset disease (44.4%). Conversely, genotype CPS V/ST1 was the most prevalent in adults (4/9; 25.4%). All isolates were susceptible to penicillin. Macrolide resistance (23.1%) was strongly associated with the ermB gene and constitutive resistance to clindamycin (63.9%). The majority of strains was resistant to tetracycline (86.6%), mostly mediated by the tetM gene (87.7%). GBS isolates of CPS V/ST1 and CPS III/ST23 were significantly associated with macrolide and tetracycline resistance, respectively. In conclusion, hyper-virulent CPS III/ST17 and V/ST1 were recognized as dominant GBS clones in this study.
European Journal of Obstetrics & Gynecology and Reproductive Biology | 2006
Vera Mijac; Slobodanka Đukić; Natasa Opavski; Milan K. Đukić; Lazar Ranin
Archives of Biological Sciences | 2014
Ina Gajic; Vera Mijac; Natasa Opavski; Maja Stanojevic; Ivana Lazarevic; Aleksandra Šmitran; Mirjana Hadnadjev; Lazar Ranin
Srpski Arhiv Za Celokupno Lekarstvo | 2013
Ina Gajic; Vera Mijac; Lazar Ranin; Dragana Andjelkovic; Miroslava Radicevic; Natasa Opavski
Archives of Biological Sciences | 2014
Mirjana Hadnadjev; Ina Gajic; Vera Mijac; Tatjana Kurucin; Anika Povazan; Aleksandra Vulin; Natasa Opavski
Archives of Biological Sciences | 2012
Ina Gajic; Natasa Opavski; Vera Mijac; Lazar Ranin
Srpski Arhiv Za Celokupno Lekarstvo | 2007
Natasa Opavski; Milan Spuran; Slobodanka Djukic; Vera Mijac; Lazar Ranin
Acta Microbiologica Et Immunologica Hungarica | 2018
Suncica Popovic; Mirjana Hadnadjev; Ina Gajic; Vera Mijac; Dusan Kekic; Aleksandra Šmitran; Lazar Ranin; Natasa Opavski