Fusobacteria behaving badly: Masquerading strains of strictly anaerobic Escherichiacoli misidentified due to the deletion of the hemB gene.

Three strictly anaerobic strains of Escherichia coli were misidentified as Fusobacterium mortiferum, due to a deletion of the hemB gene which is involved in anaerobic respiration. An unusual antimicrobial susceptibility pattern sparked the further diagnostic strategies that eventually identified these strains as true anaerobic E. coli This phenomenon is more common than appreciated and can have an impact on clinical practice including persistent and relapsing infections.

In vitro activity of eravacycline and comparator antimicrobials against 143 recent strains of Bacteroides and Parabacteroides species.

Eravacycline, a novel fluorocycline antibiotic, has been evaluated against complicated mixed aerobic/anaerobic intra-abdominal infections but scant supporting in vitro data against anaerobes has been published. We found that eravacycline had good anaerobic in vitro activity with MICs of 4 μg/ml or less against all Bacteroides and Parabacteroides strains tested, except for two B. ovatus strains that had MICs of 8 μg/ml and one strain that had an MIC of 16 μg/ml.

In vitro stability of three oral vancomycin preparations stored at 2- 5 °C and ambient room temperature for up to 60 days against 100 Clostridioides (Clostridium) difficile and 51Staphylococcus aureus strains.

Oral vancomycin is used to treat Clostridioides (Clostridium) difficile infection. Several different preparations are available including reconstituted IV solutions, vancomycin capsules, and grape flavored vancomycin oral solution kit (CutisPharma). The shelf life for IV after reconstitution varies between 7 and 14 days under refrigeration, and a standard 30 days for vancomycin oral solution kit (CutisPharma).

Comparative Activity of Omadacycline against Dog and Cat Bite Wound Isolates.

Omadacycline was tested against 125 isolates recovered from infected cat and dog bites in humans. Its activity was similar to that of other compounds in the tetracycline class, and it was active against strains exhibiting tetracycline resistance. Against anaerobic isolates, resistance to tetracyclines was more prominent and omadacycline was the most active of the group.

Comparative Activities of Relebactam, Imipenem, the Combination of the Two, and Six Comparator Antimicrobial Agents against 432 Strains of Anaerobic Organisms, Including Imipenem-Resistant Strains.

Relebactam is an important beta-lactamase inhibitor for certain aerobic organisms, but alone it has no antianaerobic activity, with most anaerobes having MICs of ≥32 μg/ml with the exception of a very few strains. There was no enhancement or antagonism of imipenem activity with the addition of relebactam, including activity against imipenem-resistant strains. The relebactam-imipenem combination had excellent overall activity against the anaerobes tested.

Activities of Pexiganan and 10 Comparator Antimicrobials against 502 Anaerobic Isolates Recovered from Skin and Skin Structure Infections.

Pexiganan, a cationic peptide, exhibited a broad range of anti-anaerobic antimicrobial activity. The MICs of studied isolates were as follows: , 16 μg/ml; other group spp., 4 μg/ml; and spp.

Activity of Pexiganan and 10 Comparator Antimicrobials against 234 Isolates, Including 93 Pasteurella Species and 50 Anaerobic Bacterial Isolates Recovered from Animal Bite Wounds.

Animal bite wounds affect more than 5 million Americans annually, resulting in 300,000 emergency department visits, 10,000 hospitalizations, and an untold number of physician office visits. Various forms of topical therapy are empirically self-employed by many patients prior to seeking medical attention. Pexiganan, a 22-amino-acid synthetic cationic analogue of the peptide magainin II, acts by selectively damaging bacterial cell membranes.

Description of two novel members of the family Erysipelotrichaceae: Ileibacterium valens gen. nov., sp. nov. and Dubosiella newyorkensis, gen. nov., sp. nov., from the murine intestine, and emendation to the description of Faecalibaculum rodentium.

To better characterize murine intestinal microbiota, a large number (187) of Gram-positive-staining, rod- and coccoid-shaped, and facultatively or strictly anaerobic bacteria were isolated from small and large intestinal contents from mice. Based on 16S rRNA gene sequencing, a total 115 isolates formed three phylogenetically distinct clusters located within the family Erysipelotrichaceae. Group 1, as represented by strain NYU-BL-A3T, was most closely related to Allobaculum stercoricanis, with 16S rRNA gene sequence similarity values of 87.

The underappreciated in vitro activity of tedizolid against Bacteroides fragilis species, including strains resistant to metronidazole and carbapenems.

Because Bacteroides fragilis has the ability to develop mechanisms of resistance to almost all antibiotics, we studied the comparative in vitro activity of tedizolid against 124 Bacteroides group species clinical isolates, including carbapenem, metronidazole and piperacillin-tazobactam resistant strains. Tedizolid had an MIC of 2 μg/ml (range, 0.5-4 μg/ml) and was 1-4 times more active than linezolid that had an MIC of 8 μg/ml (range, 2-16 μg/ml).

Reclassification of Clostridium difficile as Clostridioides difficile (Hall and O'Toole 1935) Prévot 1938.

The recent proposal by Lawson and Rainey (2015) to restrict the genus Clostridium to Clostridium butyricum and related species has ramifications for the members of the genera that fall outside this clade that should not be considered as Clostridium sensu stricto. One such organism of profound medical importance is Clostridioides difficile that is a major cause of hospital-acquired diarrhea and mortality in individuals. Based on 16S rRNA gene sequence analysis, the closest relative of Clostridium difficile is Clostridium mangenotii with a 94.

Comparison of the Copan eSwab System with an Agar Swab Transport System for Maintenance of Fastidious Anaerobic Bacterium Viability.

We compared the eSwab system to a swab with an anaerobic transport semisolid agar system for their capacities to maintain the viability of 20 species of fastidious anaerobes inoculated on the bench and held at ambient or refrigerator temperature for 24 or 48 h. On average, both systems maintained similar viabilities among analogous groups of organisms at both temperatures, although there were quantitative differences among some species.

Impact of Surotomycin on the Gut Microbiota of Healthy Volunteers in a Phase 1 Clinical Trial.

Clostridium difficile-associated diarrhea has been associated with disruption of the normal intestinal microbiota, particularly theBacteroides fragilisgroup andPrevotellaspecies. Surotomycin is a bactericidal cyclic lipopeptide in development for treatment ofClostridium difficile-associated diarrhea that has selective and potent activity againstC. difficileand other Gram-positive bacteria and a minimal impact on intestinal Gram-negative organisms.

Lactobacillus species: taxonomic complexity and controversial susceptibilities.

The genus Lactobacillus is a taxonomically complex and is composed of over 170 species that cannot be easily differentiated phenotypically and often require molecular identification. Although they are part of the normal human gastrointestinal and vaginal flora, they can also be occasional human pathogens. They are extensively used in a variety of commercial products including probiotics.

Comparative in vitro activities of dalbavancin and seven comparator agents against 41 Staphylococcus species cultured from osteomyelitis infections and 18 VISA and hVISA strains.

Due to a high rate of relapse, osteomyelitis remains difficult to treat, requiring prolonged parenteral therapy. MICs for 41 consecutive Staphylococcus species recovered from patients with osteomyelitis were determined for dalbavancin, daptomycin, doxycycline, levofloxacin, linezolid, vancomycin, trimethoprim-sulfamethoxazole, rifampin, and vancomycin. Strains of vancomycin-intermediate Staphylococcus aureus (VISA) and heteroresistant VISA were included for additional comparison.

Comparative in vitro activities of SMT19969, a new antimicrobial agent, against 162 strains from 35 less frequently recovered intestinal Clostridium species: implications for Clostridium difficile recurrence.

We determined the comparative activity of SMT19969 (SMT) against 162 strains representing 35 well-characterized Clostridium species in clusters I to XIX and 13 Clostridium species that had no 16S rRNA match. SMT MICs ranged from 0.06 to >512 μg/ml and were not species related.

Bacterial counts from five over-the-counter probiotics: are you getting what you paid for?

There is concern that the bacterial colony counts present at the time of manufacture and listed on the probiotic package may not be reflective of the numbers viable colonies at the time of purchase and patient consumption thereby diminishing efficacy. We performed a colony count study of three separate samples of five different probiotics purchased from three different stores: Bifidobacterium infantis (Align(®)); Lactobacillus acidophilus CL1285(®) and Lactobacillus casei LBC80R(®) (Bio-K+(®)); Lactobacillus rhamnosus GG (Culturelle(®)); Saccharomyces boulardii (Florastor(®)) and "L. acidophilus" and "Lactobacillus helveticus" (Lactinex(®)).

Comparative in vitro activities of SMT19969, a new antimicrobial agent, against Clostridium difficile and 350 gram-positive and gram-negative aerobic and anaerobic intestinal flora isolates.

The comparative in vitro activity of SMT19969, a novel, narrow-spectrum, nonabsorbable agent, was studied against 50 ribotype-defined Clostridium difficile strains, 174 Gram-positive and 136 Gram-negative intestinal anaerobes, and 40 Gram-positive aerobes. SMT19969 was one dilution more active against C. difficile isolates (MIC range, 0.

Anaerobic and aerobic bacteriology of the saliva and gingiva from 16 captive Komodo dragons (Varanus komodoensis): new implications for the "bacteria as venom" model.

It has been speculated that the oral flora of the Komodo dragon (Varanus komodoensis) exerts a lethal effect on its prey; yet, scant information about their specific oral flora bacteriology, especially anaerobes, exists. Consequently, the aerobic and anaerobic oral bacteriology of 16 captive Komodo dragons (10 adults and six neonates), aged 2-17 yr for adults and 7-10 days for neonates, from three U.S.

Evaluation of cycloserine-cefoxitin fructose agar (CCFA), CCFA with horse blood and taurocholate, and cycloserine-cefoxitin mannitol broth with taurocholate and lysozyme for recovery of Clostridium difficile isolates from fecal samples.

Cycloserine-cefoxitin fructose agar (CCFA), CCFA with horse blood and taurocholate (CCFA-HT), and cycloserine-cefoxitin mannitol broth with taurocholate and lysozyme (CCMB-TAL) were compared for recovery of Clostridium difficile from 120 stool specimens. Compared to CCFA, CCFA-HT enhanced C. difficile growth and improved recovery by 4%.

Differences in distribution and antimicrobial susceptibility of anaerobes isolated from complicated intra-abdominal infections versus diabetic foot infections.

Few labs isolate and perform susceptibility tests on anaerobes; therefore, we studied the differences between 1185 anaerobes isolated from complicated intra-abdominal infections and 470 isolated from moderate to severe diabetic foot infections. They differed markedly in the distribution of species, including Bacteroides fragilis and anaerobic Gram-positive cocci, as well as in resistance patterns, especially to fluoroquinolones.

Comparative in vitro activity of ceftaroline, ceftaroline-avibactam, and other antimicrobial agents against aerobic and anaerobic bacteria cultured from infected diabetic foot wounds.

Foot infections are the most common infectious complication of diabetes. Moderate to severe diabetic foot infections (DFI) are typically polymicrobial with both aerobic and anaerobic organisms. The role of MRSA in these wounds has become an increasing concern.

In vitro activity of Biapenem plus RPX7009, a carbapenem combined with a serine β-lactamase inhibitor, against anaerobic bacteria.

Biapenem is a carbapenem being developed in combination with RPX7009, a new inhibitor of serine β-lactamases. Biapenem was tested alone and in combination with fixed concentrations of RPX7009 by agar dilution against 377 recent isolates of anaerobes. A separate panel of 27 isolates of Bacteroides spp.

Comparative in vitro activities of GSK2251052, a novel boron-containing leucyl-tRNA synthetase inhibitor, against 916 anaerobic organisms.

We studied the comparative in vitro activity of GSK2251052, a novel boron leucyl-tRNA synthetase inhibitor, against 916 clinical anaerobic isolates using CLSI methods. The GSK MIC50/MIC90 for all isolates tested were 2 and 4 μg/ml, and the MIC90s against 302 Bacteroides fragilis and Bacteroides thetaiotaomicron strains were 4 and 8 μg/ml, respectively. All Clostridium perfringens strains had GSK2251052 MICs of >32 μg/ml.

Ceftaroline versus isolates from animal bite wounds: comparative in vitro activities against 243 isolates, including 156 Pasteurella species isolates.

More than 5 million Americans are bitten by animals, usually dogs, annually. Bite patients comprise ∼1% of all patients who visit emergency departments (300,000/year), and approximately 10,000 require hospitalization and intravenous antibiotics. Ceftaroline is the bioactive component of the prodrug ceftaroline fosamil, which is FDA approved for the treatment of acute bacterial skin and skin structure infections (ABSSSIs), including those containing methicillin-resistant Staphylococcus aureus (MRSA).