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Purpuse The carbapenem-resistant Bacteroides fragilis group (CR-BFG) bacteria have been reported in several countries recently with increasing global attention. The high incidence of CR-BFG isolated from our hospitalized patients has become an important problem. Therefore, we aimed to determine the frequency and associated factors for intestinal colonization by carbapenem-non-susceptible BFG (CNS-BFG) among adult patients hospitalized at intensive care units, neurosurgery and internal medicine wards in our hospital. Methods Rectal swabs (n = 1200), collected from 766 patients between February 2014 and March 2015, were inoculated onto kanamycin-vancomycin-leaked blood agar containing 0.125 mg/L meropenem. The isolates were identified by MALDI-TOF MS. Susceptibility testing was performed by agar dilution method. The carbapenemase gene (cfiA) was detected by PCR. Logistic regression analysis was used to evaluate the associated factors for intestinal colonization by CNS-BFG. Results A total 180 non-duplicate BFG isolates were obtained from 164 patients. Ten different species, including Parabacteroides distasonis (n = 46, 25.6%), and Bacteroides fragilis (n = 30; 16.6%), were identified. Twenty-five percent of the isolates were non-susceptible to meropenem (MIC >2 mg/L). The highest prevalence of meropenem resistant strains (MIC >8 mg/L) was detected among B. fragilis (n = 12), followed by Parabacteroides spp. (n = 4). All but one B. fragilis strains were cfiA gene positive. Hospital admission, increasing Charlson score, use of antibiotics; including carbapenems in past three months, colonization with other accompanying carbapenem-resistant Gram negative bacteria (Enterobacteriaceae, Acinetobacter baumannii and Pseudomonas aeruginosa), and having undergone surgical operations were significantly associated with RCS- BFG colonization. Conclusions The high carriage rate of CNS-BFG in hospitalized patients may lead to worse clinical outcomes, such as serious infections and mortality, and deserves attention.

Gram-positive anaerobic cocci (GPAC), a large group of anaerobic bacteria, are the members of the normal microbiota that colonizes the skin and mucosal surfaces of the human body. However, in case of a wound or when the host becomes immunocompromised, GPAC can cause invasive and most frequently mixed infections. GPAC are the second most frequently isolated bacteria in anaerobic infections. Although the studies are limited, GPAC have been reported to develop resistance to antimicrobial drugs. The resistance of the pathogens to the antimicrobials and improper therapy can cause poor clinical outcomes. Therefore, monitoring of the resistance trends of regional clinically important anaerobic bacteria periodically is recommended. In our study, we aimed to determine the antimicrobial susceptibility profiles of clinically important GPAC. A total of 100 non-duplicated pathogenic GPAC isolates were collected from Marmara University Hospital between 2013 and 2015. The isolates were identified by using conventional methods, "matrix-assisted laser desorption ionization-time of flight mass spectrometry system (MALDI-TOF MS)" (VITEK MS; v3.0, bioMerieux, France) and 16S rRNA gene sequencing. Antimicrobial susceptibility test was carried out by the agar dilution method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The following antimicrobials were tested: penicillin, amoxicillin/ clavulanic acid (AMC), cefoxitin, meropenem, clindamycin, erythromycin, tetracycline, tigecycline, chloramphenicol, moxifloxacin and metronidazole. The minimum inhibitory concentration (MIC) results were interpreted according to the breakpoints described by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Breakpoints recommended by CLSI for cefoxitin, tetracycline and moxifloxacin, and breakpoint recommended by Food and Drug Administration (FDA) for tigecycline were used since there were no EUCAST breakpoints for these antimicrobials. MIC50 and MIC90 values were determined for erythromycin since the breakpoint was not described by EUCAST, CLSI or FDA guidelines. The identification results showed that the strains (n= 100) consisted of five different GPAC genus; Parvomonas (40%), Finegoldia (34%), Peptoniphilus (14%), Peptostreptococcus (10%) and Anaerococcus (1%). All of the organisms were susceptible to meropenem, tigecycline and metronidazole. The isolates were highly susceptible to penicillin, AMC, cefoxitin, and chloramphenicol, since the resistance rates against these antimicrobials were 5% or less. The resistance rates against clindamycin, tetracycline and moxifloxacin were 14%, 31% and 24%, respectively. In total, 11% of the isolates were multidrug resistant. Metronidazole and tigecycline displayed high in vitro activity against GPAC and both are appropriate antimicrobials for the selection of empiric therapy. The effectiveness of meropenem was also found high, but it was observed that this antimicrobial would be more appropriate to use in the treatment of severe mixed infections accompanied by other microorganisms with the resistance potential. Detection of penicillin and AMC resistant isolates, which are frequently used in the treatment of GPAC infection, requires periodic monitoring of the antimicrobial susceptibility patterns of GPAC. The high rates of resistance against clindamycin, tetracycline and moksifloxacin indicated that these antimicrobials should not be used for empirical treatment of infections without prior antimicrobial susceptibility testing. This study is one of the largest susceptibility studies specifically carried out on GPAC to date in Turkey. We believe that our results will provide good surveillance data both for our hospital and our country.

Prevotella species, being members of the human microbiota, are obligate anaerobic gram-negative bacteria. These organisms may cause opportunistic infections, including specific oral infections, local or systemic infections. A significant increase of resistance to some antimicrobials has been detected among Prevotella species. The frequency of resistance vary among isolates from different infection sources and between geographic locations. The knowledge about the antimicrobial susceptibility patterns of different Prevotella species is limited in Turkey. Providing the antimicrobial susceptibility data of these bacteria is very important for effective empirical treatment. In this study, we aimed to determine susceptibility data for 12 antimicrobial agents against Prevotella strains originating from human infections, collected in two centers in Turkey. A total of 118 Prevotella strains, isolated from different clinical samples in Marmara University Faculty of Medicine Medical Microbiology and Istanbul University Faculty of Dentistry Oral Microbiology Laboratories between January 2014-December 2017, were tested. Organisms were identified by using MALDI-TOF MS and by 16S rRNA gene sequencing. Minimal inhibitor concentrations of ampicillin, ampicillin-sulbactam, piperacillin-tazobactam, cefoxitin, meropenem, imipenem, clindamycin, tetracycline, tigecycline, moxifloxacin and metronidazole were determined using gradiyent test methodology (E-test; bioMerieux, France) and the European Committee on Antimicrobial Susceptibility Testing, Clinical and Laboratory Standards Institute and Food and Drug Administration guidelines were used for interpretation. Thirteen different Prevotella species were identified, Prevotella bivia and Prevotella nigrescens were the most prevalent species (n= 21) followed by Prevotella buccae (n= 19). All Prevotella strains were susceptible to piperacillin-tazobactam, cefoxitin, meropenem, imipenem and tigecycline. A total of 2 (1.7%) isolates were resistant to metronidazole and 1 (0.8%) isolate was intermediately resistant to ampicillin/sulbactam. The frequency of resistant isolates against ampicillin, clindamycin, tetracycline and moxifloxacin were 57.6%, 36.4%, 18% and 16.3%, respectively. In conclusion, piperacillin/tazobactam, cefoxitin, and tigecycline displayed high in vitro activity against Prevotella spp. and they all remained good candidates for empiric therapy. Imipenem and meropenem were also found to be very active, but the usage of carbapenems should be reserved for serious mixed infections, potentially accompanied by other resistant organisms. Intermediate resistance to ampicillinsulbactam and the resistance against metronidazole emphasized the need of periodic monitoring of their susceptibility patterns. The high rates of non-susceptibility to ampicillin, clindamycin, tetracycline and moxifloxacin indicated that these antimicrobials should not be used for treatment of infections without prior antimicrobial susceptibility testing.

Gram-positive anaerobic cocci (GPAC), a large group of anaerobic bacteria, are the members of the normal microbiota that colonizes the skin and mucosal surfaces of the human body. However, in case of a wound or when the host becomes immunocompromised, GPAC can cause invasive and most frequently mixed infections. GPAC are the second most frequently isolated bacteria in anaerobic infections. Although the studies are limited, GPAC have been reported to develop resistance to antimicrobial drugs. The resistance of the pathogens to the antimicrobials and improper therapy can cause poor clinical outcomes. Therefore, monitoring of the resistance trends of regional clinically important anaerobic bacteria periodically is recommended. In our study, we aimed to determine the antimicrobial susceptibility profiles of clinically important GPAC. A total of 100 non-duplicated pathogenic GPAC isolates were collected from Marmara University Hospital between 2013 and 2015. The isolates were identified by using conventional methods, "matrix-assisted laser desorption ionization-time of flight mass spectrometry system (MALDI-TOF MS)" (VITEK MS; v3.0, bioMerieux, France) and 16S rRNA gene sequencing. Antimicrobial susceptibility test was carried out by the agar dilution method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The following antimicrobials were tested: penicillin, amoxicillin/ clavulanic acid (AMC), cefoxitin, meropenem, clindamycin, erythromycin, tetracycline, tigecycline, chloramphenicol, moxifloxacin and metronidazole. The minimum inhibitory concentration (MIC) results were interpreted according to the breakpoints described by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Breakpoints recommended by CLSI for cefoxitin, tetracycline and moxifloxacin, and breakpoint recommended by Food and Drug Administration (FDA) for tigecycline were used since there were no EUCAST breakpoints for these antimicrobials. MIC50 and MIC90 values were determined for erythromycin since the breakpoint was not described by EUCAST, CLSI or FDA guidelines. The identification results showed that the strains (n= 100) consisted of five different GPAC genus; Parvomonas (40%), Finegoldia (34%), Peptoniphilus (14%), Peptostreptococcus (10%) and Anaerococcus (1%). All of the organisms were susceptible to meropenem, tigecycline and metronidazole. The isolates were highly susceptible to penicillin, AMC, cefoxitin, and chloramphenicol, since the resistance rates against these antimicrobials were 5% or less. The resistance rates against clindamycin, tetracycline and moxifloxacin were 14%, 31% and 24%, respectively. In total, 11% of the isolates were multidrug resistant. Metronidazole and tigecycline displayed high in vitro activity against GPAC and both are appropriate antimicrobials for the selection of empiric therapy. The effectiveness of meropenem was also found high, but it was observed that this antimicrobial would be more appropriate to use in the treatment of severe mixed infections accompanied by other microorganisms with the resistance potential. Detection of penicillin and AMC resistant isolates, which are frequently used in the treatment of GPAC infection, requires periodic monitoring of the antimicrobial susceptibility patterns of GPAC. The high rates of resistance against clindamycin, tetracycline and moksifloxacin indicated that these antimicrobials should not be used for empirical treatment of infections without prior antimicrobial susceptibility testing. This study is one of the largest susceptibility studies specifically carried out on GPAC to date in Turkey. We believe that our results will provide good surveillance data both for our hospital and our country.

Prevotella species, being members of the human microbiota, are obligate anaerobic gram-negative bacteria. These organisms may cause opportunistic infections, including specific oral infections, local or systemic infections. A significant increase of resistance to some antimicrobials has been detected among Prevotella species. The frequency of resistance vary among isolates from different infection sources and between geographic locations. The knowledge about the antimicrobial susceptibility patterns of different Prevotella species is limited in Turkey. Providing the antimicrobial susceptibility data of these bacteria is very important for effective empirical treatment. In this study, we aimed to determine susceptibility data for 12 antimicrobial agents against Prevotella strains originating from human infections, collected in two centers in Turkey. A total of 118 Prevotella strains, isolated from different clinical samples in Marmara University Faculty of Medicine Medical Microbiology and Istanbul University Faculty of Dentistry Oral Microbiology Laboratories between January 2014-December 2017, were tested. Organisms were identified by using MALDI-TOF MS and by 16S rRNA gene sequencing. Minimal inhibitor concentrations of ampicillin, ampicillin-sulbactam, piperacillin-tazobactam, cefoxitin, meropenem, imipenem, clindamycin, tetracycline, tigecycline, moxifloxacin and metronidazole were determined using gradiyent test methodology (E-test; bioMerieux, France) and the European Committee on Antimicrobial Susceptibility Testing, Clinical and Laboratory Standards Institute and Food and Drug Administration guidelines were used for interpretation. Thirteen different Prevotella species were identified, Prevotella bivia and Prevotella nigrescens were the most prevalent species (n= 21) followed by Prevotella buccae (n= 19). All Prevotella strains were susceptible to piperacillin-tazobactam, cefoxitin, meropenem, imipenem and tigecycline. A total of 2 (1.7%) isolates were resistant to metronidazole and 1 (0.8%) isolate was intermediately resistant to ampicillin/sulbactam. The frequency of resistant isolates against ampicillin, clindamycin, tetracycline and moxifloxacin were 57.6%, 36.4%, 18% and 16.3%, respectively. In conclusion, piperacillin/tazobactam, cefoxitin, and tigecycline displayed high in vitro activity against Prevotella spp. and they all remained good candidates for empiric therapy. Imipenem and meropenem were also found to be very active, but the usage of carbapenems should be reserved for serious mixed infections, potentially accompanied by other resistant organisms. Intermediate resistance to ampicillinsulbactam and the resistance against metronidazole emphasized the need of periodic monitoring of their susceptibility patterns. The high rates of non-susceptibility to ampicillin, clindamycin, tetracycline and moxifloxacin indicated that these antimicrobials should not be used for treatment of infections without prior antimicrobial susceptibility testing.

WOS: 000373741100002 PubMed ID: 27058704 Background: The purpose of this study was to compare the effects of selected cements, or their combination with titanium, on the growth of two periodontopathic bacteria: Prevotella intermedia (Pi) and Fusobacterium nucleatum (Fn). Material/Methods: This study was comprised of several experimental groups: 1) Dental luting cements (glass ionomer cement, methacrylate-based resin cement, zinc-oxide eugenol cement, eugenol-free zinc oxide cement; 2) titanium discs; and 3) titanium combination cement discs. The disks were submerged in bacterial suspensions of either Fn or Pi. Planktonic bacterial growth within the test media was measured by determining the optical density of the cultures (OD600). Mean and standard deviations were calculated for planktonic growth from three separate experiments. Results: Intergroup comparison of all experimental groups revealed increased growth of Pi associated with cement-titanium specimens in comparison with cement specimens. Regarding the comparison of all groups for Fn, there was an increased amount of bacterial growth in cement-titanium specimens although the increase was not statistically significant. Conclusions: The combination of cement with titanium may exacerbate the bacterial growth capacity of Pi and Fn in contrast to their sole effect.

In this study, we aimed to detect the proportion of Candida dubliniensis among yeast strains previously identified as C. albicans by using several phenotypic methods and PCR.For this purpose, we screened 300 strains by using phenotypic tests suggested for the identification of C. dubliniensis in the literature, but we detected high proportion of false-positive reactions. Only two strains (0.6%) were detected as true C. dubliniensis by PCR and API ID 32C methods. Moreover, these two strains gave the expected results with all the phenotypic tests, including modified salt tolerance test for C. dubliniensis.In conclusion, none of the phenotypic methods, except for the modified salt tolerance test, revealed 100% successful results in discrimination of C. albicans and C. dubliniensis species. However, in the tobacco agar test, the rate of false positivity was as low as 0.6%. We suggest that in the case of absence of PCR and other automatized identification systems, these two phenotypic tests can be used in routine laboratories to obtain a presumptive result.

Objective: The aim of this study was to investigate the carbapenem resistance profiles and risk factors for colonization with carbapenem-resistant Bacteroides group CR-B in pediatric patients hospitalized in a tertiary university hospital in Turkey.Material and Methods: A prospective case-control study was performed. Rectal swab specimens n=1361 were collected from 680 hospitalized pediatric patients. All anaerobic colonies isolated from selective medium were identified using MALDI-TOF Vitek MS, bioMérieux automated system and antibiotic susceptibility testing for meropenem by e-test. The presence of the cfiA gene was investigated by PCR method.Results: A total of 1361 rectal swab specimens were collected from all 680 hospitalized children. During the screening period 80 Bacteroides fragilis group BFG microorganisms with a MIC>0.125 mg/L 12% were isolated from rectal swab specimens of 680 patients. Seven different BFG species were recovered, the main species were B.fragilis n=29; 36% , B.ovatus n=16; 20% , B.vulgatus n=13; 16% , P.distasonis n=12; 15% , B.theoiotomicron n=5; 6% , B.uniformis n=4; 5% and B.caccae n=1; 1% . The presence of cfiA gene was detected in 25 31% isolates, while 29 36% isolates were not susceptible to meropenem MIC>2 mg/L . Conclusion: The high carriage rate in our hospitalized children for carbapenem-non-susceptible Bacteroides fragilis group creates a great risk for serious infections and mortality and deserves significant attention, Amaç: Bu çalışmanın amacı, Türkiye’de üçüncü düzey bir üniversite hastanesinde yatmakta olan çocuk hastalarda karbapenem dirençli Bacteroides grup KD-B bakteriler ile kolonizasyon için risk faktörlerini ve karbapenem direnç profilini araştırmaktı.Gereç ve Yöntem: Prospektif vaka-kontrol çalışması uygulandı. Hastanede yatmakta olan 680 çocuk hastadan 1361 rektal swab toplandı. Selektif mediumdan izole edilen tüm anaerobik kolonilere identifikasyon için MALDI-TOF Vitek MS, bioMérieux otomatize sistem ve meropenem duyarlılığı için e-test uygulandı. cfiA geni PCR yöntemiyle araştırıldı.Bulgular: Hastanede yatmakta olan 680 çocuk hastadan 1361 rektal swab toplandı. Tarama süresince MIC>0.125 mg/L olan 80 Bacteroides fragilis group BFG bakteri izole edildi. Yedi farklı tür BFG saptandı, sıklık sırasına göre şöyleydi: B.fragilis n=29; %36 , B.ovatus n=16; %20 , B.vulgatus n=13; %16 , P.distasonis n=12; %15 , B.theoiotomicron n=5; %6 , B.uniformis n=4; %5 ve B.caccae n=1; %1 . 25 izolatda %31 cfiA geni saptanırken, meropeneme hassas olmama MIC>2 mg/L 29 izolatda %36 belirlendi.Sonuç: Çalışmamızda, hastanede yatan çocuklarda karbapenem hassas olmayan Bacteroides fragilis grup bakteriler ile kolonizasyon oranları yüksek bulunmuştur ki, bu durum ciddi enfeksiyonların oluşması, artmış mortalite açısından önemlidir ve dikkate alınmalıdır