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Background: A major worldwide health issue is the rising frequency of resistance of bacteria.Drug combinations are a winning strategy in fighting resistant bacteria and might help in protecting the existing drugs.Monolaurin is natural compound extracted from coconut oil and has a promising antimicrobial activity against Staphylococcus.aureus. This study aims to examine the efficacy of monolaurin both individually and in combination with β-lactam antibiotics against Staphylococcus aureus isolates. Methods: Agar dilution method was used for determination of minimum inhibitory concentration (MIC) of monolaurin against S.aureus isolates. Scanning electron microscope (SEM) was used to detect morphological changes in S.aureus after treatment with monolaurin. Conventional and Real-time Polymerase chain reaction (RT-PCR) were performed to detect of beta-lactamase (blaZ) gene and its expressional levels after monolaurin treatment. Combination therapy of monolaurin and antibiotics was assessed through fractional inhibitory concentration and time-kill method. Results: The antibacterial activity of monolaurin was assessed on 115 S.aureus isolates, the MIC of monolaurin were 250 to 2000 µg/ml. SEM showed cell elongation and swelling in the outer membrane of S.aureus in the prescence of 1xMIC of monolaurin. blaZ gene was found in 73.9% of S.aureus isolates. RT-PCR shows a significant decrease in of blaZ gene expression at 250 and 500 µg/ml of monolaurin. Synergistic effects were detected through FIC method and time killing curve. Combination therapy established a significant reduction on the MIC value. The collective findings from the antibiotic combinations with monolaurin indicated synergism rates ranging from 83.3% to 100%.In time-kill studies, combination of monolaurin and β-lactam antibiotics produced a synergistic effect. Conclusion: This study showed that monolaurin may be a natural antibacterial agent against S. aureus, and may be an outstanding modulator of β-lactam drugs. The concurrent application of monolaurin and β-lactam antibiotics, exhibiting synergistic effects against S. aureus in vitro, holds promise as potential candidates for the development of combination therapies that target particularly, patients with bacterial infections that are nearly incurable. [ABSTRACT FROM AUTHOR]

Background and Aim: Gram-negative pathogens are considered the common cause of wound infections associated with increased mortality and morbidity rates. Antibiotics combination has been used to overcome this problem. In this study, we identify Gram-negative pathogens found in wound infections and assess the in-vitro efficacy of a combination of amikacin and imipenem against the resistant isolated pathogens. Materials and Methods: One hundered fifty gram-negative bacteria were collected from two hundered patients suffering from different wound infections. Patients attended Minia University Hospitals,Egypt at period from January 2019- January 2020 and they were followed up periodically as a routine work in the hospitals. Swabs streaked on various media as Nutrient agar, MacConkey agar, Eosin methylene blue agar and cetrimide agar. The antimicrobial susceptibility of the identified pathogens was tested using the Kirby-Bauer method. Conventional PCR was used to detect the prevalence of bla-IMP and AAC (6’)-Ib genes. The effect of the tested combination was assessed by checkerboard technique and time-killing assay. Results: Escherichia coli 38.6% was the most common isolated pathogen, followed by Proteus spp 30%, P. aeruginosa 21.4%, Klebsiella spp. 5.7%, and Acinetobacter baumannii 4.3%. The isolates were completely resistant to Ampicillin/sulbactam, Amoxicillin/clavulanic, Cephalothin, Cefadroxil, Ciprofloxacin, Ceftazidime and Ofloxacin. Bla-IMP was detected in all Klebsiella spp., E. coli (85.2%), A. baumannii (66.7%), Proteus spp. (38.1%) and P. aeruginosa (33.35%). aac(6’)-Ib was detected among E. coli, P. aeruginosa and Proteus spp. The Checkerboard test showed a significant decrease in bacterial count in the presence of combination indicating a synergistic effect with FICIs ≤0.5. Time-kill assay showed a significant decrease in the bacterial count after 12h. Conclusion: The studied combinations of antibiotics showed synergistic effects against the tested Gram-negative bacteria which can help in the control and treatment of serious wound infections. [ABSTRACT FROM AUTHOR]