Intra-abdominal Infections

Synthesis and mechanistic studies of 4-aminoquinoline-Isatin molecular hybrids and Schiff's bases as promising antimicrobial agents

In this investigation, to determine their potential as specific antibacterial agents, Schiff's bases (LT-SB1-23 and SB1-SB12) and novel quinoline-isatin hybrids were subjected to microbiological testing. The in-vitro screening against bacterial strains (Escherichia coli, Enterococcus faecalis, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhi) exhibited their antibacterial potential with many of the compounds showing inhibition range of 90-100 % at 200 μg/mL, against most of the tested strains. The MIC values of some of the compounds showed good antibacterial efficacy with values ranging from 32 to 128 μg/mL. Their bacterial growth inhibitory potential was further supported by disk diffusion and growth curve assays. Interestingly, one of the Schiff's bases (LT-SB7) displayed strong synergistic activity against E. coli and S. typhi with 16-64 folds reduction in MIC values. Additionally, it exhibited up to 85 % suppression of biofilm at ½MIC against AA209 environmental bacterial isolate and reduced the development of multidrug-resistant bacterial isolates. Promising compound LT-SB7 underwent 100 ns molecular dynamics simulations with biofilm-causing protein (PDB ID: 7C7U) to assess conformational changes and complex stability. Overall, this study identified compounds as effective antibacterial alternatives for the future.

Antimicrobial Susceptibility Patterns and Clinical Parameters in 208 Dogs with Positive Urine Cultures (2012-2014)

Urinary tract infections (UTI) occur commonly in dogs, and gram-negative enteric bacteria are the most prevalent pathogens. Clinical parameters, urinalysis, and urine culture and sensitivity results were retrieved from the medical records of 208 dogs with positive urine cultures over a 3 yr period at the Louisiana State University Veterinary Teaching Hospital. Several groups were defined including dogs presented for primary care versus referred cases; simple UTI, complicated UTI, and pyelonephritis; dogs pretreated with antimicrobials; and dogs having an indwelling catheter in place prior to sampling. Nearly 80% of dogs had complicated UTI. Of all dogs, 70% had no documented clinical signs of lower urinary tract disease (LUTD), with 68% of them showing hematuria and/or pyuria. Based on clinical signs or urinalysis, 19% of all dogs had no evidence of lower UTI. In dogs without LUTD signs the most common comorbidities were immunosuppressive treatment and severely restricted mobility (23%). Chronic recurring UTI were present in 19% of dogs with LUTD signs. Distribution of bacterial species was comparable with the existing literature and not significantly different between clinical subgroups. Isolates from dogs pretreated with antimicrobials showed decreased susceptibility to enrofloxacin. The prevalence of multidrug-resistant Escherichia coli and Staphylococcus spp. was moderate (29%).