[Multilocus sequence analysis, biofilm production, antibiotic susceptibility and synergy tests of Burkholderia species in patients with and without cystic fibrosis]. / Kistik fibrozisli ve kistik fibrozisi olmayan hasta grubunda Burkholderia türlerinin multilokus sekans analizi, biyofilm olusturma, antibiyotik duyarlilik ve sinerji testleri.

Burkholderia spp. emerged as important pathogens in the airways of immunocompromised humans, especially those with cystic fibrosis (CF). Failure of identification with conventional techniques, high intrinsic resistance to most antibiotics and biofilm formation can cause difficulties in the treatment of these infections. The aim of this study was to identify Burkholderia spp. strains isolated from CF and non-CF patients with with routine microbiological methods, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and multilocus sequence analysis (MLSA), to determine of the antibiotic susceptibility and synergies, and to evaluate biofilm formation of these isolates. A total of 38 Burkholderia spp. (25 CF, 13 non-CF) from 26 patients were identified by biochemical, phenotypical and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and sequence types were revealed by multilocus sequence analysis (MLSA). Sequence types of isolates were identified using the PubMLST database. Characteristics of biofilm formation of clinical isolates were evaluated by microplate method. Antibiotic susceptibilities of ceftazidime, meropenem, trimethoprim-sulfamethoxazole (TMP-SXT) and levofloxacin were determined by broth microdilution method according to CLSI (2017) guidelines. Synergy tests were performed by checkerboard method. Clinical isolates were identified as Burkholderia cenocepacia (n= 16), Burkholderia contaminans (n= 11), Burkholderia gladioli (n= 4), Burkholderia dolosa (n= 4), Burkholderia multivorans (n= 2) and Burkholderia seminalis (n= 1). Sequence types of these isolates were determined as ST19, ST72, ST102, ST180, ST482, ST602, ST629, ST740, ST839 and ST1392. The correct identification at the species-level with MALDI-TOF MS was 94-100% for all isolates except B.contaminans. Biofilm formation among the identified species in the study was determined as 53% (n= 20). There was no statistical difference when the biofilm production was evaluated separately among Burkholderia species and biofilm production rates between CF (56%, 14/25) and non-CF (46%, 6/13) Burkholderia isolates (p> 0.05). Overall rates of resistance to ceftazidime, meropenem, TMP-SXT, and levofloxacin of the isolates were 35%, 66%, 50% and 40%, respectively. The antibiotic resistance against Burkholderia spp., isolates obtained from CF patients were more susceptible to ceftazidime, but no significant difference was found for other antibiotics. Synergy was determined between meropenem and TMP-SXT in two isolates. Antagonism was detected in 15 isolates, 12 of them were between meropenem and ceftazidime, three of them were between ceftazidime and TMP-SXT. Numerous resistance mechanisms may lead to higher resistance in this bacteria, whereas the antagonism between meropenem and ceftazidime in this study might be attributed to the expression of beta-lactamases. In this study, the distinctness of sequence types between Burkholderia spp. isolated from CF and non-CF patient, provided a better understanding about the importance of biofilm formation for the infections with these bacteria and emphasized that the management of therapy should be driven by the antibiotic test results.

Serotype distribution of Streptococcus pneumonia in children with invasive disease in Turkey: 2015-2018.

Objectives: To determine the serotype distribution of pneumococcus causing invasive pneumococcal disease (meningitidis, bacteremia and empyema) in children in Turkey, and to observe potential changes in this distribution in time to guide effective vaccine strategies. Methods: We surveyed S. pneumoniae with conventional bacteriological techniques and with real-time polymerase chain reaction (RT-PCR) in samples of cerebrospinal fluid (CSF), blood and pleural fluid. S. pneumoniae strains were isolated from 33 different hospitals in Turkey, which are giving health services to approximately 60% of the Turkish population. Results: A total of 167 cases were diagnosed with invasive pneumococcal disease between 2015 and 2018. We diagnosed 52 (31.1%) patients with meningitis, 104 (62.2%) patients with bacteremia, and 11 (6.6%) patients with empyema. Thirty-three percent of them were less than 2 years old and 56% less than 5 years old. Overall PCV13 serotypes accounted for 56.2% (94/167). The most common serotypes were 19 F (11.9%), 1 (10.7%) and 3 (10.1%). Conclusions: Besides the increasing frequency of non-vaccine serotypes, vaccine serotypes continue to be a problem for Turkey despite routine and high-rate vaccination with PCV13 and significant reduction reported for the incidence of IPD in young children. Since new candidate pneumococcal conjugate vaccines with more serotype antigens are being developed, continuing IPD surveillance is a significant source of information for decision-making processes on pneumococcal vaccination.

Neisseria meningitidis Serogroup X ST-5799 (ST-22 complex) in Turkey: A unique pediatric case.

Although outbreaks of Neisseria meningitidis serogroup X occured in a couple of African countries, a limited number of serogroup X meningococcal cases were reported in America and Europe as well as Turkey. Additionally, serogroup X is still not represented in current conjugated meningococcal vaccines. Here, we describe the first pediatric case with meningitis caused by Neisseria meningitidis serogroup X ST-5799 (ST-22 complex) that formed a distinct lineage.