Browsing by Author "Tošić, Tanja (8326509800)"

Actinobacillus actinomycetemcomitans, a constituent of the oral flora, is a rare cause of brain abscesses. We report the case of a 47-year-old male who presented with multiple brain abscesses due to this organism, presumably originating from his poor dentition. Problems met in isolating and identifying A. actinomycetemcomitans suggest that its true rate of isolation from non-oral samples may have been underestimated. Copyright © APMIS 2005.

Background: The global epidemic of nosocomial diarrhea caused by Clostridioides (Clostridium) difficile started in 2000, with high mortality rates and emergence of a new hypervirulent strain NAP1/BI/027. The aim of this study was to assess the presence of ribotype 027 and other C. difficile ribotypes in a Serbian University Hospital, compare the temporal variability of ribotypes 3 years apart, as well as to compare clinical, demographic and laboratory characteristics and disease outcome among patients infected with 027 and non-027 ribotype. This was a prospective observational cohort study addressing 4-month intervals during 2014/2015 and 2017/2018. Results: Ribotyping was performed in 64 non-duplicate C. difficile strains. Ribotype 027 was the most prevalent, and was detected in 53 (82.8%) patients (43/45 and 10/19 patients in 2014-2015 and 2017/2018, respectively). Other detected ribotypes were 001/072 in 4 (6.3%), 002 in 4 (6.3%), 014/020 in 2 (3.1%) and 176 in 1 (1.5%) patient. The percentage of the patients infected with ribotype 027 significantly decreased during the 3-year period, from 95.6 to 52.6% (p < 0.001). Ribotype 027 infection was associated with fluoroquinolone treatment more frequently than infection with other ribotypes [33 (62.3%) vs. 2 (18.2%), p = 0.010)]. A severe C. difficile infection was diagnosed more often in patients with the detected ribotype 027 compared to those infected with non-027 ribotypes (p = 0.006). No significant difference in the mortality and recurrence rates was found between the patients infected with ribotype 027 and those infected with other ribotypes [10/53 (18.8%) vs. 2/11 (18.2%), p = 0.708, and 10/35 (28.6%) vs. 0/2 (0%), p = 1.000, respectively]. Conclusion: Clostridium difficile ribotype 027 was the most prevalent ribotype among patients in a large Serbian hospital, but there is a clear decreasing trend. © 2020 The Author(s).

Background: The global epidemic of nosocomial diarrhea caused by Clostridioides (Clostridium) difficile started in 2000, with high mortality rates and emergence of a new hypervirulent strain NAP1/BI/027. The aim of this study was to assess the presence of ribotype 027 and other C. difficile ribotypes in a Serbian University Hospital, compare the temporal variability of ribotypes 3 years apart, as well as to compare clinical, demographic and laboratory characteristics and disease outcome among patients infected with 027 and non-027 ribotype. This was a prospective observational cohort study addressing 4-month intervals during 2014/2015 and 2017/2018. Results: Ribotyping was performed in 64 non-duplicate C. difficile strains. Ribotype 027 was the most prevalent, and was detected in 53 (82.8%) patients (43/45 and 10/19 patients in 2014-2015 and 2017/2018, respectively). Other detected ribotypes were 001/072 in 4 (6.3%), 002 in 4 (6.3%), 014/020 in 2 (3.1%) and 176 in 1 (1.5%) patient. The percentage of the patients infected with ribotype 027 significantly decreased during the 3-year period, from 95.6 to 52.6% (p < 0.001). Ribotype 027 infection was associated with fluoroquinolone treatment more frequently than infection with other ribotypes [33 (62.3%) vs. 2 (18.2%), p = 0.010)]. A severe C. difficile infection was diagnosed more often in patients with the detected ribotype 027 compared to those infected with non-027 ribotypes (p = 0.006). No significant difference in the mortality and recurrence rates was found between the patients infected with ribotype 027 and those infected with other ribotypes [10/53 (18.8%) vs. 2/11 (18.2%), p = 0.708, and 10/35 (28.6%) vs. 0/2 (0%), p = 1.000, respectively]. Conclusion: Clostridium difficile ribotype 027 was the most prevalent ribotype among patients in a large Serbian hospital, but there is a clear decreasing trend. © 2020 The Author(s).

Objectives: In humans, enterococci are among the most important opportunistic pathogens. This study aims to compare invasive isolates obtained from blood cultures of patients with sepsis and endocarditis with colonizing isolates obtained from healthy donors’ stool samples. Methods: A case-by-case assessment was conducted on invasive infection cases to determine whether enterococci were involved in their pathogenesis. They were tested for the presence of virulence factor genes, β-hemolysis on agars supplemented with human and sheep blood, and biofilm forming capacity. Results: Three species of enterococci were identified among invasive isolates: Enterococcus faecalis, Enterococcus faecium, and Enterococcus durans. All endocarditis isolates were biofilm producers. Genes esp, gelE, asa1, ace, hyl, cylB, and cylA were present in 7 (41.2%), 11 (64.7%), 11 (64.7%), 13 (76.5%), 0, 3 (17.6%), and 1 (5.9%) invasive isolate, but none of them could be linked to a particular infection (sepsis or endocarditis). Colonizing isolates proved to have had more virulence factor genes, but the differences were not statistically significant. Members of that group produced a greater amount of biofilm when the ace gene was absent (p = 0.047). The production of β-hemolysis by noninvasive strains was detected more frequently when agar was supplemented with human blood (p = 0.021). In general, the presence of either cyl gene on that specific agar was in direct connection with the production of β-hemolysis: cylA (p = 0.047) or cylB (p = 0.020). Conclusion: We have been unable to establish any correlation between invasive isolates and any virulence gene carriage and biofilm formation. β-hemolysis was produced significantly more often by colonizing strains when agar had been supplemented with human blood. © The Author(s) 2023.

Objectives: In humans, enterococci are among the most important opportunistic pathogens. This study aims to compare invasive isolates obtained from blood cultures of patients with sepsis and endocarditis with colonizing isolates obtained from healthy donors’ stool samples. Methods: A case-by-case assessment was conducted on invasive infection cases to determine whether enterococci were involved in their pathogenesis. They were tested for the presence of virulence factor genes, β-hemolysis on agars supplemented with human and sheep blood, and biofilm forming capacity. Results: Three species of enterococci were identified among invasive isolates: Enterococcus faecalis, Enterococcus faecium, and Enterococcus durans. All endocarditis isolates were biofilm producers. Genes esp, gelE, asa1, ace, hyl, cylB, and cylA were present in 7 (41.2%), 11 (64.7%), 11 (64.7%), 13 (76.5%), 0, 3 (17.6%), and 1 (5.9%) invasive isolate, but none of them could be linked to a particular infection (sepsis or endocarditis). Colonizing isolates proved to have had more virulence factor genes, but the differences were not statistically significant. Members of that group produced a greater amount of biofilm when the ace gene was absent (p = 0.047). The production of β-hemolysis by noninvasive strains was detected more frequently when agar was supplemented with human blood (p = 0.021). In general, the presence of either cyl gene on that specific agar was in direct connection with the production of β-hemolysis: cylA (p = 0.047) or cylB (p = 0.020). Conclusion: We have been unable to establish any correlation between invasive isolates and any virulence gene carriage and biofilm formation. β-hemolysis was produced significantly more often by colonizing strains when agar had been supplemented with human blood. © The Author(s) 2023.

Introduction. Multifocal cerebritis is a rare and severe disease and just a several cases caused by Listeria monocytogenes were described in the literature. Case report. A 64 year old man was admitted to the hospital with disturbed consciounsness (Glasgow Coma Scale score: 9) after being febrile for 16 days with history of fever, headache and middle ear pain. He did not have any other comorbidities neither he was immunocompromised. Penicillin allergy was noted for him. On neurologic exam, meningeal or focal neurologic signs were not evident, but computed tomography (CT) brain scan with contrast injection showed 3 hypodense zones in the occipital and 1 in the right temporal lobe. Laboratory findings in blood and cerebrospinal fluid (CSF) were indicative for the infectious nature of changes in the endocranium (multifocal cerebritis). Initial therapy was the combination of cefotaxime, amikacin and metronidazole, but after the isolation of L. monocytogenes from CSF and blood culture, therapy was switched to co-trimoxazole. Recovery of consciouscness with establisment of alert state occurred after 6 days of co-trimoxazole administration. Total therapy took 36 days. During that period all clinical and laboratory parameters normalized. The patient was discharged as recovered, with sequelas of amnesia and slurring of speech. Conclusion. In the treatment of multifocal cerebritis caused by L. monocytogenes, adequate choice and long-term therapy with antibiotics are necessary. The drug of choice is ampicillin but in the case of allergy to it, co-trimoxazole is a good replacement. © 2020 Inst. Sci. inf., Univ. Defence in Belgrade. All rights reserved.

Introduction: In an intensive care unit (ICU) of the Emergency Center in the Clinical Center of Serbia, four species of vancomycin resistant enterococci (VRE) were isolated in a 17-month period mostly from blood cultures, including E. faecalis, E. faecium, E. raffinosus and E.gallinarum. Methodology: The relationship between isolates from each species was investigated by PFGE, and PCR experiments for detection of pathogenicity factor genes and van genes to determine the nature of each clone. A PCR-based method, using 10 primer pairs (p1/2-p19/20), was used to investigate the presence of the Tn1546-like structure. Results: PFGE indicated the presence of two different E. faecium clones, while the three other enterococcal species belonged to one clone each. Transposon typing revealed that isolates of E. raffinosus (4), E. gallinarum (4) and E. faecalis (3) yielded gene sequences identical to 10 primer pairs (p1/2-p19/20), suggesting the possibility of identical transposon-like structure in these species. Conclusions: The results of the study indicate probable horizontal spread of Tn1546-like structure in three species of VRE obtained from the same ICU. © 2017 Jovanović et al.

Introduction: In an intensive care unit (ICU) of the Emergency Center in the Clinical Center of Serbia, four species of vancomycin resistant enterococci (VRE) were isolated in a 17-month period mostly from blood cultures, including E. faecalis, E. faecium, E. raffinosus and E.gallinarum. Methodology: The relationship between isolates from each species was investigated by PFGE, and PCR experiments for detection of pathogenicity factor genes and van genes to determine the nature of each clone. A PCR-based method, using 10 primer pairs (p1/2-p19/20), was used to investigate the presence of the Tn1546-like structure. Results: PFGE indicated the presence of two different E. faecium clones, while the three other enterococcal species belonged to one clone each. Transposon typing revealed that isolates of E. raffinosus (4), E. gallinarum (4) and E. faecalis (3) yielded gene sequences identical to 10 primer pairs (p1/2-p19/20), suggesting the possibility of identical transposon-like structure in these species. Conclusions: The results of the study indicate probable horizontal spread of Tn1546-like structure in three species of VRE obtained from the same ICU. © 2017 Jovanović et al.

In this study the distribution of species and antimicrobial resistance among vancomycin resistant enterococci (VRE) recovered from clinical specimens obtained from five hospitals in Belgrade was analyzed. Strains were further characterized by pulsed-field gel electrophoresis (PFGE). Polymerase chain reaction (PCR) was used to investigate the presence of vanA and vanB genes and pathogenicity factor genes. Identification of 194 VRE isolates revealed 154 Enterococcus faecium, 21 Enterococcus faecalis, 10 Enterococcus raffinosus and 9 Enterococcus gallinarum. This study revealed existence of 8 major clones of VRE. PCR determined vanA gene to be present in all of the VRE studied. Esp and hyl genes were present in 29.22% and 27.92% of E. faecium, respectively, and in 76.19% and 0 of E. faecalis, respectively. Esp and hyl genes were not found more frequently in members of predominant clones of E. faecium than in single isolates; nor was their presence connected to invasiveness. © 2015 Akadémiai Kiadó, Budapest.

In this study the distribution of species and antimicrobial resistance among vancomycin resistant enterococci (VRE) recovered from clinical specimens obtained from five hospitals in Belgrade was analyzed. Strains were further characterized by pulsed-field gel electrophoresis (PFGE). Polymerase chain reaction (PCR) was used to investigate the presence of vanA and vanB genes and pathogenicity factor genes. Identification of 194 VRE isolates revealed 154 Enterococcus faecium, 21 Enterococcus faecalis, 10 Enterococcus raffinosus and 9 Enterococcus gallinarum. This study revealed existence of 8 major clones of VRE. PCR determined vanA gene to be present in all of the VRE studied. Esp and hyl genes were present in 29.22% and 27.92% of E. faecium, respectively, and in 76.19% and 0 of E. faecalis, respectively. Esp and hyl genes were not found more frequently in members of predominant clones of E. faecium than in single isolates; nor was their presence connected to invasiveness. © 2015 Akadémiai Kiadó, Budapest.

Background: The incidence of Clostridium difficile infections (CDI) in the Clinical Center of Serbia (CCS) and the entire Serbia has been constantly rising in the previous 5 years. We aimed to study C. difficile PCR-ribotypes isolated from patients hospitalized at two healthcare institutions: CCS and Specialized Hospital for Cerebrovascular Diseases “Sveti Sava” (SS), both of them from Belgrade, and to investigate the incidence rates of CDI in hospital settings in Serbia, from 2009 to 2013. Methods: The Bacteriology laboratory database at Clinic for Infectious and Tropical Diseases of CCS was queried from January 1, 2009 to December 31, 2013 for all patients who underwent immunochromatographic toxin A and/or toxin B stool testing and C. difficile stool culture for suspected infection caused by this bacterium. Toxigenic culture was not performed. Ninety- six C. difficile isolates were then selected and characterized by PCR-ribotyping. These were obtained from 94 patients hospitalized in different clinics of CCS and SS from November 2011 to December 2013. Results: Among 6164 stool samples sent to Bacteriology laboratory for culture of C. difficile and toxin detection during the study period, 1775 (28.8%) were positive, displaying linear trend of growth. From 96 isolates, typed by PCR-ribotyping, majority (85; 88.54%) belonged to PCR-ribotype 027. The remaining 11 isolates belonged to PCR-ribotypes 014/020 (3 isolates), 015, SLO 191 (two isolates each), 017, 018, 070 and 001/072 (one isolate each). Conclusion: Our results demonstrated that C. difficile PCR-ribotype 027 is by far predominant in two hospital settings in Belgrade, at least since 2011. © 2018 Elsevier Ltd

Background: The incidence of Clostridium difficile infections (CDI) in the Clinical Center of Serbia (CCS) and the entire Serbia has been constantly rising in the previous 5 years. We aimed to study C. difficile PCR-ribotypes isolated from patients hospitalized at two healthcare institutions: CCS and Specialized Hospital for Cerebrovascular Diseases “Sveti Sava” (SS), both of them from Belgrade, and to investigate the incidence rates of CDI in hospital settings in Serbia, from 2009 to 2013. Methods: The Bacteriology laboratory database at Clinic for Infectious and Tropical Diseases of CCS was queried from January 1, 2009 to December 31, 2013 for all patients who underwent immunochromatographic toxin A and/or toxin B stool testing and C. difficile stool culture for suspected infection caused by this bacterium. Toxigenic culture was not performed. Ninety- six C. difficile isolates were then selected and characterized by PCR-ribotyping. These were obtained from 94 patients hospitalized in different clinics of CCS and SS from November 2011 to December 2013. Results: Among 6164 stool samples sent to Bacteriology laboratory for culture of C. difficile and toxin detection during the study period, 1775 (28.8%) were positive, displaying linear trend of growth. From 96 isolates, typed by PCR-ribotyping, majority (85; 88.54%) belonged to PCR-ribotype 027. The remaining 11 isolates belonged to PCR-ribotypes 014/020 (3 isolates), 015, SLO 191 (two isolates each), 017, 018, 070 and 001/072 (one isolate each). Conclusion: Our results demonstrated that C. difficile PCR-ribotype 027 is by far predominant in two hospital settings in Belgrade, at least since 2011. © 2018 Elsevier Ltd

Objectives: Antibiotic use and immunocompromised status in haematology patients have been shown to determine the constituents of commensal microbiota with highly increased resistance, including vancomycin resistant enterococci. We compared the carriage of virulence factor genes and the capacity for biofilm formation in vancomycin resistant enterococci (VRE) originating from the oropharyngeal and stool cultures of haematology patients. Design: PCR tests were used to investigate the presence of genes encoding pathogenicity factors (esp and hyl) in VRE isolates. The genotype of vancomycin resistance was investigated by multiplex PCR tests for vanA and vanB genes. PFGE typing was conducted to exclude the duplicate isolates. Results: Of 3310 pharyngeal swabs taken from inpatients at a clinic for haematology, Enterococcus species were recovered in 6.46%. All VRE investigated were identified as Enterococcus faecium and were highly vancomycin resistant. VanA genotype was confirmed in all. In the group of oropharyngeal carriers (n = 8 patients), 15 strains were recovered from oropharyngeal specimens and PFGE typing revealed 5 types and 3 subtypes. Identical types of VRE in the oropharynx and stool cultures were found in three patients from this group. In the group of stool carriers (n = 24 patients) VRE were obtained from stools only and placed in 21 macro-restriction patterns. The esp gene was more common in VRE isolated from the oropharynx than in isolates from stools (p = 0.014). Results were not significant when we compared the presence of hyl genes in oropharyngeal isolates with those from stool cultures (p = 0.66) or when we investigated the association between esp and hyl gene carriage and capability of biofilm formation in non-repeated VRE. Conclusions: In the present study, isolation of VRE from the oropharynx in haematology patients was associated with esp gene carriage. Further research is needed to investigate the clinical and long-term effects of this finding. © 2018 Elsevier Ltd

Objectives: Antibiotic use and immunocompromised status in haematology patients have been shown to determine the constituents of commensal microbiota with highly increased resistance, including vancomycin resistant enterococci. We compared the carriage of virulence factor genes and the capacity for biofilm formation in vancomycin resistant enterococci (VRE) originating from the oropharyngeal and stool cultures of haematology patients. Design: PCR tests were used to investigate the presence of genes encoding pathogenicity factors (esp and hyl) in VRE isolates. The genotype of vancomycin resistance was investigated by multiplex PCR tests for vanA and vanB genes. PFGE typing was conducted to exclude the duplicate isolates. Results: Of 3310 pharyngeal swabs taken from inpatients at a clinic for haematology, Enterococcus species were recovered in 6.46%. All VRE investigated were identified as Enterococcus faecium and were highly vancomycin resistant. VanA genotype was confirmed in all. In the group of oropharyngeal carriers (n = 8 patients), 15 strains were recovered from oropharyngeal specimens and PFGE typing revealed 5 types and 3 subtypes. Identical types of VRE in the oropharynx and stool cultures were found in three patients from this group. In the group of stool carriers (n = 24 patients) VRE were obtained from stools only and placed in 21 macro-restriction patterns. The esp gene was more common in VRE isolated from the oropharynx than in isolates from stools (p = 0.014). Results were not significant when we compared the presence of hyl genes in oropharyngeal isolates with those from stool cultures (p = 0.66) or when we investigated the association between esp and hyl gene carriage and capability of biofilm formation in non-repeated VRE. Conclusions: In the present study, isolation of VRE from the oropharynx in haematology patients was associated with esp gene carriage. Further research is needed to investigate the clinical and long-term effects of this finding. © 2018 Elsevier Ltd