Phenotypes and genotypes of macrolide-resistant Streptococcus pneumoniae in Serbia

Although macrolides are widely used for treating pneumococcal infections, an increase in macrolide resistance might compromise their use. The objective of this study was to determine the prevalence of macrolide-resistant phenotypes and genotypes in macrolide-resistant S. pneumoniae isolates in Serbia. A total of 228 macrolide-resistant strains isolated during the period of 2009-2012, were analyzed. Macrolide resistance phenotypes were determined by a double disk diffusion test. The presence of macrolide resistance genes was detected by PCR. Antibiotics susceptibilities were tested using the VITEK2 system and E test. Among the examined isolates, the MLSB phenotype which is linked to the presence of the erm(B) gene dominated (83.3%), while the mef(A) gene which is associated with the M phenotype, was identified in 16.7% isolates. Over 40% of isolates expressed co-resistance to penicillin. A multiple-resistant pattern was found in 36.4% strains, more frequently in children. However, all strains were susceptible to telithromycin, vancomycin, linezolid, fluoroquinolones and rifampicin. [Projekat Ministarstva nauke Republike Srbije, br. 175039

The most common isolates from pleural infections

Isolation and identification of the pathogens are important for appropriate treatment of pleural infections. Distribution of the most frequent causative agents varies throughout the world and may change in time.The objective of the study is to analyze the bacteriological isolates of pleural fluids in order to identify the most frequent infectious agents and assess their variability in time.The retrospective study included 272 patients with positive pleural fluid samples analyzed in 5-year period. The samples were examined using the conventional microbiological technique.Of 315 bacterial isolates the most common were streptococcal species, 105 (33%), of which 55 (17.3%) represented the Streptococcus milleri group. Gram-positive anaerobic cocci were detected in 56 (17.6%) isolates. Enterobacteriaceae family included 27 (8.5%) isolates and Pseudomonas aeruginosa was registered in 13 (4.1%). No statistically significant difference was registered in pathogen distribution in the examined period (p = 0.288).The most common agents of community-acquired pleural infections are the Streptococcus milleri group and anaerobic Gram-positive cocci. They differ from the most common pathogens of pneumonia. Among the hospital-acquired pleural infections, Pseudomonas species, Staphylococcus aureus and enterobacteria prevail. The distribution of bacterial agents isolated in the 5-year period exhibits no significant differences

Use of immunochromatographic assay for rapid identification of Mycobacterium tuberculosis complex from liquid culture

A new, simple immunochromatographic assay for rapid identification of Mycobacterium tuberculosis complex in liquid cultures has been developed. The principle of the assay is binding of the Mycobacterium tuberculosis complex specific antigen to the monoclonal antibody conjugated on the test strip. The aim of this study is evaluation of the performance of immunochromatographic assay in identification of Mycobacterium tuberculosis complex in primary positive liquid cultures of BacT/Alert automated system. A total of 159 primary positive liquid cultures were tested using the immunochromatographic assay (BD MGIT TBc ID) and the conventional subculture, followed by identification using biochemical tests. Of 159 positive liquid cultures, using the conventional method, Mycobacterium tuberculos is was identified in 119 (74.8%), nontuberculous mycobacteria were found in 4 (2.5%), 14 (8.8%) cultures were contaminated and 22 (13.8%) cultures were found to be negative. Using the immunochromatographic assay, Mycobacterium tuberculosis complex was detected in 118 (74.2%) liquid cultures, and 41 (25.8%) tests were negative. Sensitivity, specificity, positive and negative predictive values of the test were 98.3%; 97.5%; 99.15%; 95.12%, respectively. The value of kappa test was 0.950, and McNemar test was 1.00. The immunochromatographic assay is a simple and rapid test which represents a suitable alternative to the conventional subculture method for the primary identification of Mycobacterium tuberculosis complex in liquid cultures of BacT/Alert automated system

Actinomyces Odontolyticus -Associated Bacteremia

Abstract Many Actinomyces species are part of the oral microflora of humans. Actinomyces odontolyticusassociated infections are exceptionally rare, presenting an endogenous infection originating from mucous membranes. Immunodeficiency is often complicated by severe opportunistic bacterial infections leading to critical condition of the patient. We report a case of an immunosuppressed patient with fever and Actinomyces odontolyticus bacteremia. The patient poorly responded to the applied antimicrobial therapy and did not recover

Diagnostic approach to localised organising pneumonia: A case report

Introduction. Localised organising pneumonia, radiologically presented with oval or round shadows mimicing lung cancer or metastases, is a major issue in differential diagnosis. Case report. A female patient was hospitalized to clarified the etiology of multiple nodular lung lesions. The chest X-ray and the chest computed tomography (CT) revealed bilateral patchy and nodular shadows, and round lung lesions, respectively. Neither sputum analyses, nor histology of bronchoscopy samples clarified the etiology of these lung lesions. As secondary deposits in the lungs were suspected, video-assisted thoracoscopy and anterolateral right minithoracotomy with atypical upper and lower lobe resection were performed. The frozen-section analysis suggested the benign nature of the lesion, and the definite histopathological finding of localised organising pneumonia was established. Due to bilateral lung lesions, corticosteroids were applied. Seven weeks later, the chest CT finding revealed a total regression of the lesions. Conclusion. A surgical resection was necessary to diagnose the localised organising pneumonia which mimiced secondary malignant lesions, thus establishing the definite etiology of lung lesions. Bronchoscopic cryobiopsy, recently introduced in order to obtain peripheral lung biopsy samples, has provided new possibilities in the diagnosis and treatment of neoplastic and non-neoplastic lung diseases

Non-susceptibility trends among methicillin-resistant coagulase-negative staphylococci isolated from blood cultures

Coagulase-negative staphylococci are a significant cause of hospital-acquired bacteremias. There is an increase of infections induced by methicillin-resistant strains, with growing resistance to other antibiotics. The aim of the study was to analyze the resistance of methicillin-resistant coagulase-negative staphylococci isolated from hemocultures in a five-year period. The study was carried out in the microbiology laboratory of the Institute for Pulmonary Diseases of Vojvodina, from 2008 to 2013. Coagulase-negative staphylococci were isolated from 196 hemocultures. Susceptibility tests were performed using the disc diffusion method. Of 196 coagulase-negative staphylococci, 122 (62.2%) were resistant to methicillin, of which 112 (91.8%), 105 (86.1%), 103 (84.4%), 88 (72.1%) were resistant to erythromycin, gentamicin, ciprofloxacin and clindamycin, respectively. All strains were susceptible to vancomycin and linezolid. Multiple resistance was registered in 100 (82%) strains. The most common resistance pattern was gentamicin-erythromycin-clindamycinciprofloxacin. Multiple resistance was established in a significant percentage of methicillin-resistant strains

Listeria monocytogenes isolated in ready-to-eat food in South Bačka region of Vojvodina province, Serbia

Listeria monocytogenes is pathogenic bacterium that can contaminate food products during and after processing. As ready-to-eat food does not undergo any treatment to ensure its safety before consumption, the risk of foodborne disease must be considered if this pathogen is present in the food. As diseases caused by contaminated food are an important public health problem today, the aim of this study was to determine the prevalence of Listeria monocytogenes in different ready-to-eat food products. In the seven-month period from June 1 to December 31, 2011, a total of 1 380 food samples were examined in the Division of Sanitary Bacteriology, Center for Microbiology, Institute of Public Health of Vojvodina in Novi Sad. A total of 912 samples were analyzed for the presence of Listeria monocytogenes according to ISO 11290-2. The identity of suspected Listeria monocytogenes was confirmed using the VITEK 2 Compact system (BioMerieux, France). Out of 912 samples, Listeria monocytogenes was detected in 18 (1.97%). Listeria monocytogenes was mostly found in cooked meals (in 6 samples out of 18), sandwiches (4 samples) and frozen food, such as ice-cream and frozen vegetables (4 samples). It was also found in tofu bread spreads (2 samples), cream cheese (1 sample) and cakes (1 sample). The presence of Listeria monocytogenes in some ready-to-eat food could present a public health hazard, particularly to the high-risk population group, because of the high mortality rate associated with listeriosis and the widespread nature of the organism. Monitoring of listeriosis is essential to prevent foodborne outbreaks, and in assessing human health risk in ready-to-eat foods