[Phylotyping and Determining the Antimicrobial Susceptibility of Cutibacterium acnes Isolated from Patients with Acne Vulgaris]. / Akne Vulgarisli Hastalardan Üretilen Cutibacterium acnes Izolatlarinin Filotiplendirilmesi ve Antimikrobiyallere Duyarlilik Durumlarinin Belirlenmesi.

Cutibacterium acnes (formerly known as Propionibacterium acnes), obligate anaerobic gram-positive diphtheroid, is a member of normal skin microbiota and frequently isolated from acne lesions and also in various infections as an opportunist pathogen. Within the last decade, distinct phylogroups of C.acnes have been discovered, and specific strains associated with human disease were defined. Increasing resistance to antimicrobials used in the treatment of C.acnes infections has been reported. Resistance rates vary among isolates from different geographic locations. However, knowledge about the antimicrobial susceptibility patterns of C.acnes is limited in Turkey. Determining the phylotypes of C.acnes isolates and providing antimicrobial susceptibility data will be very useful in understanding the pathogenesis of the disease, preventing the development of resistance, and applying rational and effective empirical treatment. The aim of this study was to determine the phylotypes and antimicrobial susceptibility patterns of C.acnes and to investigate the relationship among C.acnes phylotypes, the severity of acne and the antimicrobial resistance. C.acnes isolates cultivated from the acne lesions of 57 patients who admitted to the dermatology outpatient clinic of our university hospital and from the skin of 62 healthy control group in a six-month period were included in the study. The acne lesions on the face and chest/upper back were given a score according to the Global acne grading system (GAGS) for describing the severity of acne. The severity was graded as mild if the score was 1-18, moderate with scores from 19 to 30, severe with scores from 31 to 38, and as very severe if the score is more than 39. The isolates were identified by using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) . Phylotype analysis was performed by polymerase chain reaction (PCR) using specific primers. The minimum inhibitory concentrations (MICs) of clindamycin, erythromycin, azithromycin, tetracycline and doxycycline were determined by agar dilution technique recommended by Clinical and Laboratory Standards Institute (CLSI) for anaerobic bacteria. The majority of the isolates (patient; n= 47, control; n= 47) in both of the patient and control groups were phylotype IA, followed by type IB and type II, respectively and no type III C.acnes was detected. There was no correlation between acne severity and bacterial phylotypes. The resistance rates of clindamycin, erythromycin, azithromycin, tetracycline and doxycycline were found to be 22.8%, 29.8%, 35.2%, 3.5% and 5.3% in the acne patients group, respectively, whereas in the control group the incidence of resistance to these antimicrobials was 11.3%, 21%, 38.7%, 1.6% and 1.6%, respectively. There was no significant difference in antimicrobial resistance between the patient and control groups, except erythromycin (p= 0.043, Fisher's exact) as well as no relationship was found between antimicrobial resistance and phylotypes in both of the groups. The number of isolates, resistant to two or more antimicrobials, was higher in the patients with acne. C.acnes isolates were highly resistant to clindamycin, erythromycin and azithromycin. Type IA constituted the majority of the phylotypes. There was no significant relationship between C.acnes phylotype, antimicrobial resistance and acne severity.

[Antimicrobial Susceptibility of Pathogenic Gram-positive Anaerobic Cocci: Data of a University Hospital in Turkey]. / Patojen Gram-Pozitif Anaerop Koklarin Antimikrobiyal Ilaçlara Duyarliliklari: Türkiye'den Bir Üniversite Hastanesi Verileri.

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.

[Antimicrobial Susceptibility Profiles of Prevotella Species Determined by Gradient Test Method in Two Centers in Istanbul]. / Istanbul'da Iki Merkeze ait Prevotella Türlerinin Gradiyent Test Yöntemiyle Belirlenen Antimikrobiyal Ilaç Duyarliligi.

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.

[In Vitro Activities of Antimicrobials Against Toxigenic Clostridioides difficile Isolates Obtained in a University Training and Research Hospital in Turkey]. / Türkiye'deki Bir Üniversite Egitim ve Arastirma Hastanesinde Elde Edilen Toksijenik Clostridioides difficile Izolatlarina Antimikrobiyallerin In Vitro Etkisi.

Clostridioides difficile, a gram-positive, anaerobic, spore forming bacillus known as Clostridium difficile according to the previous taxonomy, is the most important agent of antibiotic-associated diarrhea. C.difficile infections have become a major health problem for many countries. The rate of antimicrobial resistant C.difficile isolates is rapidly increasing all around the world. Yet there is limited data on this subject in our country. The aim of this study was to determine the antimicrobial susceptibility profiles of C.difficile strains isolated from stool samples in Marmara University Pendik Training and Research Hospital Microbiology Laboratory. A total of 93 toxigenic C.difficile, defined by serological and molecular techniques, were included in this study. Antimicrobial susceptibility profiles of isolates were determined by using agar dilution method according to the Clinical and Laboratory Standards Institute (CLSI; M11-A7). The following antimicrobials commonly used for the treatment of C.difficile infections or applied previously in C.difficile epidemiological studies were tested: metronidazole, vancomycin, meropenem, ceftriaxone, ampicillin-sulbactam, clindamycin, erythromycin, moxifloxacin, tetracycline, doxycycline, tigecycline and linezolid. 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 were applied for ceftriaxone, clindamycin, tetracycline and moxifloxacin since there were no EUCAST breakpoints for these antimicrobials. MIC50 and MIC90 values were determined for three antimicrobials (linezolid, erythromycin, doxycycline) whose breakpoints were not described by EUCAST or CLSI guidelines. All isolates were susceptible to metronidazole, vancomycin, ampicillin-sulbactam, meropenem and tetracycline. Susceptibility to ceftriaxone, clindamycin and moxifloxacin was found in 58.1%, 35.5% and 20.4% of the isolates, respectively. MIC50 and MIC90 values of tigecycline, erythromycin linezolid, doxycycline were 0.125-0.25 mg/L, 1-2 mg/L, 2-2 mg/L, 0.062- 0.125 mg/L, respectively. This study shows the current antimicrobial susceptibility patterns of C.difficile isolates in our hospital and will also be the reference data for clinical laboratories in our country where anaerobic culture and susceptibility tests are not performed in routine practice. In conclusion, two main antimicrobial agents commonly used in the treatment of C.difficile infections, metronidazole and vancomycin, seem to be effective. However, high resistance rates against to the certain tested antimicrobials highlight the need for further surveillance to monitor the emergence of resistance.

Performance of mass spectrometric identification of clinical Prevotella species using the VITEK MS system: A prospective multi-center study.

Prevotella species, members of the human microbiota, can cause opportunistic infections. Rapid and accurate identification of Prevotella isolates plays a critical role in successful treatment, especially since the antibiotic susceptibility profile differs between species. Studies, mostly carried out using the Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) Biotyper system, showed that MALDI-TOF MS is an accurate, rapid and satisfactory method for the identification of clinically important anaerobes. In this multi-center study, we assessed the performance of the MALDI-TOF MS VITEK MS system for the identification of clinical Prevotella isolates. A total of 508 Prevotella isolates, representing 19 different species, collected from 11 European countries, Kuwait and Turkey between January 2014 and April 2016, were identified using VITEK MS (v3.0). The reliability of the identification was assessed by 16S rRNA gene sequencing. Using VITEK MS, 422 (83.1%) of the 508 isolates were identified on the species level, 459 (90.4%) on the genus level. A total of 49 (9.6%) isolates were not identified correctly. 16S rRNA gene sequencing results showed that this was partly due to the fact that several species were not represented in the database. However, some species that were represented in the database were also not identified. Five Prevotella strains were misidentified at the genus level, 2 of these strains belonged to a species not represented in the database. In general, the VITEK MS offers a reliable and rapid identification of Prevotella species, however the databases needs to be expanded.

A multicenter survey of antimicrobial susceptibility of Prevotella species as determined by Etest methodology.

Knowledge about the antimicrobial susceptibility patterns of different Prevotella species is limited. The aim of this study was to determine the current antimicrobial susceptibility of clinical isolates of Prevotella species from different parts of Europe, Kuwait and Turkey. Activity of 12 antimicrobials against 508 Prevotella isolates, representing 19 species, were tested according to Etest methodology. EUCAST, CLSI and FDA guidelines were used for susceptibility interpretations. All Prevotella species were susceptible to piperacillin/tazobactam, imipenem, meropenem, tigecycline and metronidazole. Ampicillin/sulbactam and cefoxitin also showed good activity. Ampicillin, clindamycin, tetracycline and moxifloxacin were less active; 51.2%, 33.7%, 36.8% and 18.3% of isolates were non-susceptible, respectively. A total of 49 (9.6%) isolates were resistant to three or more antimicrobials. Prevotella bivia was the most prevalent species (n = 118) and accounted for most of the multidrug-resistant isolates. In conclusion, the level of non-susceptibility to antimicrobials, which may be used for treatment of infections involving Prevotella species, are a cause of concern. This data emphasizes the need for species level identification of clinical Prevotella isolates and periodic monitoring of their susceptibility to guide empirical treatment.

Clostridium difficile: A rare cause of pyogenic liver abscess.

Extra-intestinal infections due to Clostridium difficile have been reported rarely. Herein we report a case of pyogenic liver abscess from toxigenic C. difficile in an 80-year-old non-hospitalized woman with diabetes mellitus, cerebrovascular and cardiovascular diseases. The patient was admitted to the emergency department with fever and abdominal pain. There was no history of diarrhea or use of antibiotics. Laboratory parameters revealed signs of inflammation and elevated AST and ALT levels. Abdominal ultrasound and computer tomography showed multiple focal lesions in the bilateral liver lobes and hydropic gallbladder with stones. The patient underwent cholecystectomy and the liver abscesses were drained. Toxigenic C. difficile strains were isolated from the drained pus and also from the stool sample. According to repetitive-element PCR (rep-PCR) analyses both organisms were the same. The organisms were susceptible to antibiotics. Despite proper antibiotic therapy and surgical drainage, the patient succumbed to her illness.

Peptoniphilus duerdenii sp. nov. and Peptoniphilus koenoeneniae sp. nov., isolated from human clinical specimens.

Two previously uncharacterized strains of Gram-reaction-positive, anaerobic, coccus-shaped bacteria, designated strains WAL 18896(T) and WAL 18898(T), were recovered from human wound specimens and characterized using phenotypic, chemotaxonomic and molecular taxonomic methods. Comparative 16S rRNA gene sequence analysis and chemotaxonomic and biochemical characteristics demonstrated that these organisms are genotypically and phenotypically distinct and represent previously unidentified sublines within the order Clostridiales in the phylum Firmicutes. Pairwise sequence analysis demonstrated that the novel organisms had 91.9% sequence similarity to each other and were most closely related to members of the genus Peptoniphilus. The major long-chain fatty acids of both strains were C(16:0,) C(18:0), C(18:1)ω9c and C(18:2)ω6,9c. Based on the phenotypic and phylogenetic findings, strains WAL 18896(T) ( = CCUG 56065(T)  = ATCC BAA-1640(T)) and WAL 18898(T) ( = CCUG 56067(T)  = ATCC BAA-1638(T)  = DSM 22616(T)) represent two novel species, for which the names Peptoniphilus duerdenii sp. nov. and Peptoniphilus koenoeneniae sp. nov. are proposed, respectively.

Frequency and associated factors for carbapenem-non-susceptible Bacteroides fragilis group bacteria colonization in hospitalized patients: Case control study in a university hospital in Turkey.

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.

Hospital acquired Clostridioides difficile infection and risk factors for severity in a university hospital: A prospective study.

BACKGROUND: Clostridioides difficile infection (CDI) is a well-known cause of health care-associated diarrhea. Data about CDI epidemiology of Turkey is limited. This study investigates CDI incidence, clinical characteristics, and factors associated with severe CDI in a tertiary care center university hospital. METHODS: This is a case control study was conducted between 2012 and 2016. We included all patients, 18 years of age or more, with CDI diagnosis. For each patient diagnosed with CDI, information was collected concerning the severity of disease, treatment regimen, treatment response, disease recurrence, 30-day case fatality. Cases defined as severe hospital acquired CDI (HA-CDI) and controls defined as non-severe CDI patients. RESULTS: We identified 100 cases of HA-CDI out of 111 patients. Total CDI incidence was 1.19/10,000 patient-days. The incidence decreased 32.5% during the study period. We identified severe CDI in 24% of patients. Age and admission to intensive care unit were independent risk factors for severe CDI. CONCLUSION: This study reports a 5-year prospective epidemiology of CDI in a tertiary care center in Istanbul, Turkey. The findings of this study suggest that HA-CDI incidence and proportion of severe CDI is low compared to European and US literature. We believe that CDI is underreported, neglected but still an important health care associated infection in Turkey.

Evaluation of direct 16S rRNA PCR from clinical samples for bacterial detection in normally sterile body sites.

INTRODUCTION: In addition to antibiotic treatment, slow-growing and non-cultivable bacteria can lead to false-negative results for sterile body site infections. In this study, we investigated the efficacy of 16S rRNA polymerase chain reaction (PCR) for such infections. METHODOLOGY: Following routine culture procedures, 16S ribosomal RNA (16S rRNA) PCR was performed for samples collected from sterile body sites between July 2017and September 2018. The samples were separated into two groups for likely (group 1) and unlikely infections (group 2) based on clinical and laboratory findings, as well as clinician opinion. Sequence analysis was performed for PCR-positive samples using 16S rRNA primers. Mixed chromatograms were analyzed with the RipSeq Mixed program, and Stata 15.1 was used for statistical analysis. RESULTS: Eighty-seven of 139 samples collected from 116 patients were placed in group 1, and 52 were placed in group 2. Compared with culture as the reference method, the sensitivity, specificity, positive predictive value, and negative predictive value for 16S rRNA PCR were 89.8%, 85.6%, 77.2%, and 93.9%, respectively. 16S rRNA PCR identified infections in 13 culture-negative samples. Among these, three had Bartonella quintana, Mycoplasma salivarium, and Mycobacterium avium complex infections, which cannot be detected with commercial multiplex PCR kits. CONCLUSIONS: Our study demonstrates that 16S rRNA PCR is effective for the diagnosis of sterile body site infections, especially for cases of meningitis and infective endocarditis where routine cultures fail.

Lactococcus lactis spp lactis infection in infants with chronic diarrhea: two cases report and literature review in children.

Lactococcus lactis is a gram-positive, facultative anaerobic coccus that is occasionally isolated from human mucocutaneous surfaces such as the intestines. It is used in the dairy industry for milk acidification and is mostly nonpathogenic in immunocompetent humans, however a number of cases of infection with L. lactis have been reported in recent years. In this article, we describe two cases of infection due to L. lactis in patients with chronic diarrhea. The first case is a five-month-old boy who was operated on for volvulus on his first day of life and had ileostomy with subsequent diagnosis of chronic diarrhea and bacteremia due to L. Lactis. The second case is a six-month-old girl with the diagnosis of chronic diarrhea that developed after a catheter-related bloodstream infection. Both of the infections due to L. Lactis spp lactis were successfully treated with intravenous vancomycin therapy. Although Lactococcus species is mostly known as nonpathogenic, it should be kept in mind as a potential pathogen, especially in patients with gastrointestinal disorders.

Murdochiella asaccharolytica gen. nov., sp. nov., a Gram-stain-positive, anaerobic coccus isolated from human wound specimens.

Two strains of previously unknown Gram-stain-positive, anaerobic, coccus-shaped bacteria from human wound specimens were characterized using phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequencing studies and distinguishable biochemical characteristics demonstrated that these two unknown strains, WAL 1855C(T) and WAL 2038E, are genotypically homogeneous and constitute a novel lineage within Clostridium cluster XIII. There was 13-14 % 16S rRNA gene sequence divergence between the novel strains and the most closely related species, Parvimonas micra, Finegoldia magna and species of Helcococcus. Based on the phenotypic and phylogenetic findings, a novel genus and species, Murdochiella asaccharolytica gen. nov., sp. nov., are proposed. Strain WAL 1855C(T) (=ATCC BAA-1631(T) =CCUG 55976(T)) is the type strain of Murdochiella asaccharolytica.

Gemella asaccharolytica sp. nov., isolated from human clinical specimens.

Three strains of an unidentified Gram-stain-variable, fastidious, catalase-negative, capnophilic, non-spore-forming, coccus-shaped bacterium from human wound specimens were characterized by phenotypic and molecular taxonomic methods. Initially, these strains were anaerobic; with repeated culture, they became aerotolerant. Comparative 16S rRNA gene sequencing studies demonstrated that the unknown strains were genealogically homogeneous and constituted a novel subline within the genus Gemella. The unknown bacterium was readily distinguished from other Gemella species by biochemical tests. On the basis of both phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium from clinical specimens be classified as Gemella asaccharolytica sp. nov. The type strain is WAL 1945J(T) (=ATCC BAA-1630(T) =CCUG 57045(T)).

The distribution of the bft alleles among enterotoxigenic Bacteroides fragilis strains from stool specimens and extraintestinal sites.

Enterotoxigenic Bacteroides fragilis (ETBF) has been implicated in diarrhoeal illness in animals and humans. Recent data suggest that ETBF is associated with flares of inflammatory bowel disease. Toxigenicity is attributed to expression of a toxin referred to as fragilysin, which stimulates fluid accumulation in ligated intestinal segments and alter the morphology of human intestinal cells. Three different isoforms or variants of the enterotoxin gene, designated bft-1, bft-2, and bft-3, have been identified. In this study we investigated the distribution of bft alleles among ETBF strains in stool specimens from patients with colon cancer (n: 31), the control patients (n: 8) and extraintestinal sources (n: 15). We used restriction fragment length polymorphism analysis of the PCR-amplified enterotoxin gene and sequencing the PCR-product to detect the isoforms of bft gene. Among the stool strains, bft-1 was found to be more common than bft-2; as it was detected 27 of 31 strains from colon cancer patients and 7 of 8 control strains. The bft-1 isoform was also found in almost all isolates from extraintestinal sites. No bft-3 subtype was detected among all tested strains.

Antimicrobial susceptibilities of Bacteroides fragilis and Bacteroides thetaiotaomicron strains isolated from clinical specimens and human intestinal microbiota.

Species of Bacteroides fragilis group bacteria are the most prevalent pathogens and have the highest resistance rates to antimicrobial agents among anaerobic bacteria. Infections due to these micro-organisms often originate from patient's own intestinal microbiota. The objective of the study was to determine and compare the susceptibility profiles of clinical and intestinal B. fragilis and B. thetaiotaomicron strains against certain antimicrobials. Isolates were identified by conventional methods and API-20 A. Susceptibility tests were performed according to recommendations of NCCLS (M 11-A4) agar dilution methods. Beta-lactamase production was determined with nitrocefin discs. Forty-five clinical isolates (33 B. fragilis and 12 B. thetaiotaomicron) were from following sites: blood (n:8), intra-abdominal abscess (n:7), soft tissue (n:26), and miscellaneous foci of infection (n:4). Fifty B. fragilis and 60 B. thetaiotaomicron isolates from intestinal microbiota of individuals with no history of antimicrobial treatment within last 30 days were also examined. Beta-lactamase production was detected in 93% of clinical and 99% of intestinal isolates. The organisms including intestinal isolates were uniformly susceptible to metronidazole. The MIC90s of other antibiotics and resistance rates of all clinical isolates to those antibiotics were as follows: 256 microg/mL (93%) for ampicillin, 128 microg/mL (13%) for piperacillin, 64 microg/mL (11%) for cefoxitin, 1 microg/mL (2%) for amoxicillin-clavulanate, 0.5 microg/mL (2%) for imipenem, >256 microg/mL (36%) for clindamycin, 8 microg/mL (2%) for chloramphenicol. Intestinal isolates demonstrated similar resistance rates and MIC90s. Metronidazole, imipenem, amoxicillin-clavulanate seem to be effective drugs against these bacteria in Turkey.