Effectiveness of cephalosporins in hydrolysis and inhibition of Staphylococcus aureus and Escherichia coli biofilms.

IMPORTANCE: Staphylococcus aureus and Escherichia coli contribute to global health challenges by forming biofilms, a key virulence element implicated in the pathogenesis of several infections. OBJECTIVE: The study examined the efficacy of various generations of cephalosporins against biofilms developed by pathogenic S. aureus and E. coli. METHODS: The development of biofilms by both bacteria was assessed using petri-plate and microplate methods. Biofilm hydrolysis and inhibition were tested using first to fourth generations of cephalosporins, and the effects were analyzed by crystal violet staining and phase contrast microscopy. RESULTS: Both bacterial strains exhibited well-developed biofilms in petri-plate and microplate assays. Cefradine (first generation) showed 76.78% hydrolysis of S. aureus biofilm, while significant hydrolysis (59.86%) of E. coli biofilm was observed by cefipime (fourth generation). Similarly, cefuroxime, cefadroxil, cefepime, and cefradine caused 78.8%, 71.63%, 70.63%, and 70.51% inhibition of the S. aureus biofilms, respectively. In the case of E. coli, maximum biofilm inhibition (66.47%) was again shown by cefepime. All generations of cephalosporins were more effective against S. aureus than E. coli, which was confirmed by phase contrast microscopy. CONCLUSIONS AND RELEVANCE: Cephalosporins exhibit dual capabilities of hydrolyzing and inhibiting S. aureus and E. coli biofilms. First-generation cephalosporins exhibited the highest inhibitory activity against S. aureus, while the third and fourth generations significantly inhibited E. coli biofilms. This study highlights the importance of tailored antibiotic strategies based on the biofilm characteristics of specific bacterial strains.

Effects of sub-lethal concentrations of lindane on histo-morphometric and physio-biochemical parameters of Labeo rohita.

Lindane is a broad-spectrum insecticide widely used on fruits, vegetables, crops, livestock and on animal premises to control the insects and pests. The extensive use of pesticides and their residues in the soil and water typically join the food chain and thus accumulate in the body tissues of human and animals causing severe health effects. The study was designed to determine the toxicity effects of sub-lethal concentrations of lindane on hemato-biochemical profile and histo-pathological changes in Rohu (Labeo rohita). A significant increase in the absolute (p<0.05) and relative (p<0.05) weights was observed along with severe histo-pathological alterations in liver, kidneys, gills, heart and brain at 30µg/L and 45µg/L concentration of lindane. A significant (p<0.05) decrease in RBCs count, PCV and Hb concentration while a significant (p<0.05) increased leukocytes were observed by 30µg/L and 45µg/L concentrations of lindane at 45 and 60 days of the experiment. Serum total protein and albumin were significantly (p<0.05) decreased while hepatic and renal enzymes were significantly (p<0.05) increased due to 30µg/L and 45µg/L concentrations of lindane at days-45 and 60 of experiment compared to control group. The observations of thin blood smear indicated significantly increased number of erythrocytes having nuclear abnormalities in the fish exposed at 30µg/L and 45µg/L concentrations of lindane. ROS and TBARS were found to be significantly increased while CAT, SOD, POD and GSH were significantly decreased with an increase in the concentration and exposure time of lindane. The results showed that lindane causes oxidative stress and severe hematological, serum biochemical and histo-pathological alterations in the fish even at sub-lethal concentrations.