In-vitro activity of sparfloxacin, pefloxacin, ciprofloxacin and temafloxacin against clinical isolates of Acinetobacter spp

Correlation of Gut Microbiome Between ASD Children and Mothers and Potential Biomarkers for Risk Assessment

Variation of maternal gut microbiota may increase the risk of autism spectrum disorders (ASDs) in offspring. Animal studies have indicated that maternal gut microbiota is related to neurodevelopmental abnormalities in mouse offspring, while it is unclear whether there is a correlation between gut microbiota of ASD children and their mothers. We examined the relationships between gut microbiome profiles of ASD children and those of their mothers, and evaluated the clinical discriminatory power of discovered bacterial biomarkers. Gut microbiome was profiled and evaluated by 16S ribosomal RNA gene sequencing in stool samples of 59 mother–child pairs of ASD children and 30 matched mother–child pairs of healthy children. Significant differences were observed in the gut microbiome composition between ASD and healthy children in our Chinese cohort. Several unique bacterial biomarkers, such as Alcaligenaceae and Acinetobacter, were identified. Mothers of ASD children had more Proteobacteria, Alphaproteobacteria, Moraxellaceae, and Acinetobacter than mothers of healthy children. There was a clear correlation between gut microbiome profiles of children and their mothers; however, children with ASD still had unique bacterial biomarkers, such as Alcaligenaceae, Enterobacteriaceae, and Clostridium. Candidate biomarkers discovered in this study had remarkable discriminatory power. The identified patterns of mother–child gut microbiome profiles may be important for assessing risks during the early stage and planning of personalized treatment and prevention of ASD via microbiota modulation.

Treatment of Acinetobacter infections

Gram-negative non-fermentative aerobic bacilli are becoming increasingly more involved in nosocomial infections. It has generally been recognised that the members of the Acinetobacter genus are among the most common agents responsible for severe hospital infections; their clinical importance has increased due to the development of antibacterial resistance mechanisms by these organisms. Over the last two decades the antibacterial armamentarium has progressed significantly and newer broad spectrum antibiotics have been used during therapy of hospital infections due to drug-resistant Acinetobacter spp. Despite various mechanisms of resistance to beta-lactams, aminoglycosides, fluoroquinolones developed by these organisms, the control of Acinetobacter infections can be effected by the use of several antibiotic combinations in 'conventional' antibiotic therapy. Recent surveys have pointed out the importance of using combinations of 2-amino-5-thiazolyl cephalosporins, or imipenem with aminoglycosides, or alpha-carboxy- penicillins (ticarcillin) combined with beta-lactamase inhibitors. Amongst the latter drugs, the place of sulbactam should be redefined thanks to its intrinsic activity against the Acinetobacter species, associated with its inhibitory power against beta-lactamases. The fluoroquinolones were initially very active against Acinetobacter infections, but resistance to this major class of drugs has occurred very rapidly. However, newer compounds of this class with increased anti-Acinetobacter activities can be used in combinations with beta-lactams or aminoglycosides. The potential role of rifampicin is still underestimated for the treatment of Acinetobacter infections despite promising in vitro activity. Novel derivatives of cephalosporins, carbapenems, fluoroquinolones, or completely new antibiotic classes, of which several investigational drugs seem promising, may constitute the future of antibiotic therapy and hence the treatment of Acinetobacter infections.

Epidemiological typing and prevalence of integrons in multiresistant Acinetobacter strains

Seventy-seven Acinetobacter isolates were recovered from patients in a Korean hospital during the period from November to December 1998. The isolates were genotyped using randomly amplified polymorphic DNA (RAPD) analysis for epidemiological relationship, and investigated for antibiotic susceptibility and presence of integrons. Sixty-nine Acinetobacter baumannii isolates were distributed into five groups by RAPD profiles, with 5, 1, 60, 2 and 1 in each group. The major RAPD group of 60 isolates was further divided into six subgroups by antibiograms. Eight isolates belonging to Acinetobacter DNA group 13TU were distributed among six RAPD groups. Seventy-three of the Acinetobacter isolates were resistant to eight or more of the antibiotics tested. Integrase genes were detected in 66 of the 69 A. baumannii (96%) and in 5 of the 8 Acinetobacter DNA group 13TU isolates (63%). The intI1 and intI2 genes were found in 63 and 8 isolates, respectively. The intI3 gene was not detected. All integron-carrying isolates were resistant to multiple antibiotics. All strains isolated from more than one patient carried integrons. According to the results, the presence of integrons was significantly (p<0.01) associated with multiple antibiotic resistance and nosocomial spread in Acinetobacter strains.

Comparative activity of trovafloxacin, alone and in combination with other agents, against gram-negative nonfermentative rods

In the first part of this study, agar dilution MICs were used to test the activities of trovafloxacin, ciprofloxacin, ofloxacin, levofloxacin, sparfloxacin, clinafloxacin, ceftazidime, and imipenem against 458 gram-negative nonfermenters. The overall respective MICs at which 50% of isolates are inhibited (MIC50s) and MIC90s were as follows: trovafloxacin, 1.0 and 16.0 microg/ml; ciprofloxacin, 2.0 and 16.0 microg/ml; ofloxacin, 2.0 and 32.0 microg/ml; levofloxacin, 1.0 and 16.0 microg/ml; sparfloxacin, 1.0 and 16.0 microg/ml; clinafloxacin, 0.5 and 4.0 microg/ml; ceftazidime, 8.0 and 128.0 microg/ml; imipenem, 2.0 and 256.0 microg/ml. Clinafloxacin was the most active of all the quinolones tested. The MIC90s of trovafloxacin were < or = 4.0 microg/ml for Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Flavobacterium odoratum, and Chryseobacterium meningosepticum; trovafloxacin MIC90s were < or = 2.0 microg/ml for Moraxella spp., Pseudomonas stutzeri, and Chryseobacterium indologenes-C. gleum. Of the other quinolones tested, the MICs of sparfloxacin and levofloxacin were lower than those of ciprofloxacin and ofloxacin. High ceftazidime MICs (> or = 32.0 microg/ml) were observed for all nonfermentative species tested. Although for the majority of strains tested imipenem MICs were < or = 8.0 microg/ml, high imipenem MICs were observed for many species, especially S. maltophilia, Burkholderia cepacia, F. odoratum, and Chryseobacterium meningosepticum. For Alcaligenes xylosoxidans strains, the MICs of all compounds were generally a few dilutions lower than those for Alcaligenes faecalis-A. odorans. Time-kill studies with five strains revealed that trovafloxacin and all quinolones yielded more rapid time-kill kinetics than ceftazidime and imipenem. Synergy testing by checkerboard titrations of 286 strains with trovafloxacin combined with ceftazidime, amikacin, and imipenem revealed fractional inhibitory concentration (FIC) indices in the range indicating synergism (< or = 0.5) for 81, 41, and 40 strains, respectively, and FIC indices indicating additivity or indifference (> 0.5 to 4.0) for 205, 245, and 246 strains, respectively. No FIC indices indicating antagonism (> 4.0) were observed. Synergy between trovafloxacin and ceftazidime was found for 32 of 36 S. maltophilia strains. Time-kill studies with 20 strains showed that for most strains for which FIC indices were in the range indicating additivity or indifference, FIC indices indicated synergy by the time-kill method. Synergy was particularly noticeable for S. maltophilia strains with combinations of ceftazidime and trovafloxacin.

Activities of levofloxacin, ofloxacin, and ciprofloxacin, alone and in combination with amikacin, against acinetobacters as determined by checkerboard and time-kill studies

A total of 101 Acinetobacter genospecies (77 Acinetobacter baumannii strains and 24 non-A. baumannii strains) were tested for their susceptibilities to levofloxacin, ofloxacin, and ciprofloxacin and for synergy between the quinolones and amikacin by checkerboard titration and time-kill analyses. The MICs at which 50% of the isolates are inhibited (MIC50)/MIC90s for the 101 strains were as follows (in micrograms per milliliter): levofloxacin, 0.25/16.0; ofloxacin, 0.5/32.0; ciprofloxacin, 0.25/> 64.0; and amikacin, 1.0/> 32.0. At empiric breakpoints of < or = 2.0 microg/ml, 61% of the strains were susceptible to all three quinolones. At a breakpoint of < or = 16.0 microg/ml, 84% of the strains were susceptible to amikacin. Checkerboard titrations yielded synergistic fractional inhibitory concentration (FIC) indices (< or = 0.5) for one strain with levofloxacin and amikacin and for two strains with ofloxacin and amikacin. Indices of > 0.5 to 1.0 were seen for 57, 54, and 55 strains with levofloxacin plus amikacin, ofloxacin plus amikacin, and ciprofloxacin plus amikacin, respectively, and indices of > 1.0 in 43, 45, and 46 strains, respectively, were found with the above three combinations. No strains yielded antagonistic FIC indices (> 4.0). Most FIC results of > 1.0 occurred in strains for which the quinolone MICs were > 2.0 microg/ml and for which the amikacin MICs were > or = 32.0 microg/ml. By contrast, synergy (defined as > or = 2 log10 decrease compared to the more active compound alone by time-kill analysis) was found in all seven strains tested for which the quinolone MICs were < or = 2.0 microg/ml. For eight other strains for which the quinolone MICs were > 2.0 microg/ml as determined by time-kill analysis, quinolone and amikacin concentrations in combination were usually too high to permit clinical use. Time-kill analysis was found to be more sensitive in detecting synergy than was the checkerboard method.

Sparfloxacin worldwide in vitro literature: isolate data available through 1994

Sparfloxacin is a piperazinyl, cyclopropyl-fluoroquinolone with broad-spectrum antibacterial activity. Compared to other quinolones, sparfloxacin displays improved activity against a variety of pathogens including Staphylococcus, Streptococcus, Enterococcus, Chlamydia, Mycoplasma, Ureaplasma, and Mycobacteria species. Other susceptible organism group include Haemophilus, Legionella, Moraxella, Neisseria, Aeromonas, Acinetobacter, Bordetella, Brucella, Campylobacter, Gardnerella, and Helicobacter species. Most Enterobacteriaceae are also susceptible, whereas most isolates of Pseudomonas aeruginosa are not. Sparfloxacin is bactericidal. Activity is generally stable to variations of inoculum, pH, and cation concentration, and it is unchanged in the presence of 5% sodium cholate or 70% human serum. Susceptibility to the drug is diminished in urine. Cross-resistance, although incomplete, has been documented with other quinolones, but not with other antimicrobic classes.

Susceptibilities of non-Pseudomonas aeruginosa gram-negative nonfermentative rods to ciprofloxacin, ofloxacin, levofloxacin, D-ofloxacin, sparfloxacin, ceftazidime, piperacillin, piperacillin-tazobactam, trimethoprim-sulfamethoxazole, and imipenem

Agar dilution MICs of 10 agents against 410 non-Pseudomonas aeruginosa gram-negative nonfermentative rods were determined. MICs at which 50 and 90% of the isolates were inhibited, respectively, were as follows (in micrograms per milliliter): sparfloxacin, 0.5 and 8.0; levofloxacin, 1.0 and 8.0; ciprofloxacin, 2.0 and 32.0; ofloxacin, 2.0 and 32.0; D-ofloxacin, 32.0 and > 64.0; ceftazidime, 8.0 and 64.0; piperacillin with or without tazobactam, 16.0 and > 64.0; trimethoprim-sulfamethoxazole, 0.5 and > 64.0; imipenem, 2.0 and > 64.0. With the exception of those for Stenotrophomonas maltophilia, Burkholderia cepacia, and Alcaligenes faecalis-A. odorans, agar dilution MICs for all strains tested were within 1 dilution of inhibitory (bacteriostatic) levels as determined by time-kill methodology.