Susceptibility and Synergistic Effects of Guava Plant Extract and Antimicrobial Drugs on Escherichia coli

Introduction Psidium guajava (guava) is a fruit plant of the Myrtaceae family. Guava roots, leaves, and fruits have traditionally been used to prevent and treat various infections. In the last few decades, there has been exponential growth in herbal medicine. Therefore, the present study was conducted to determine the susceptibility and synergistic properties of the antimicrobial activity of the aqueous leaf extract of guava and other antimicrobial drugs against Escherichia coli (E. coli). Methodology A prospective observational study was conducted at the Department of Microbiology, MGM Medical College and Hospital, Navi Mumbai, India, involving 180 urine samples collected from patients who exhibited symptoms of urinary tract infection (UTI). The aim was to evaluate in vitro synergism between leaf extracts of guava and antimicrobial drugs on uropathogenic E. coli, using minimal inhibitory concentration (MIC) and the Kirby-Bauer method. The Kirby-Bauer disc diffusion method was employed to determine the synergistic activity using Muller-Hinton agar (MHA), and the zone of inhibition was measured in millimeters. Results The study found that, of the 180 urine samples collected from patients with UTI, significant growth was observed in 93 samples, with the most notable increase seen in E. coli. The antibiotics tobramycin, ofloxacin, and amikacin, each showing a sensitivity of 76% and 70% respectively, were found to be the most sensitive. Conversely, cefuroxime and cephalothin, both at 76%, were the most resistant. Furthermore, the antibiotic sensitivity pattern of E. coli without guava extract demonstrated tobramycin (TOB) at 76.66%, followed by ofloxacin (OF) and amikacin (AK) at 70% each, levofloxacin (LE) at 63.33%, nitrofurantoin (NIT) at 53.33%, trimethoprim (TR) at 43.33%, cefotaxime (CTX) at 36.66%, ceftizoxime (CZX) at 30%, norfloxacin (NR) at 26.66%, cephalothin (CEP) at 23.33%, amoxicillin-clavulanate (AMC) at 20%, and cefuroxime (CXM) at 10%. In contrast, when the antibiotic sensitivity pattern of E. coli with guava extract was examined, the highest sensitivity was noted for OF (100%), followed by LE (96.66%), TOB (93.33%), AK (90%), NIT (76.66%), AMC and TR (66.66% each), CTX (60%), CZX (53.33%), CEP (50%), NX (43.33%), and CXM (26.66%). Therefore, Psidium guajava (guava) extract exhibited a synergistic effect when combined with antibiotics, most notably with ofloxacin. Conclusion The study revealed that the highest synergistic activity of guava plant leaf extract was with the antibiotic ofloxacin. This finding indicates that guava extract enhances the effectiveness of commonly used antibiotics for treating UTI, an effect mainly attributed to the flavonoid compounds and their derivatives in the guava leaf extract, which inhibit bacterial growth. This study demonstrated the antibacterial properties of guava, suggesting that combining antibiotics with guava extract can help delay the emergence of bacterial resistance.

Synthesis of a statistically exhaustive fluorescent peptide substrate library for profiling protease specificity

A statistically exhaustive, 8800 compound tripeptidal amidomethylcoumarin library was synthesized as discreet compounds using solid-phase combinatorial chemistry. A subset of the compounds was purified by HPLC and tested in a high-throughput fluorometric assay against several known serine and cysteine proteases to demonstrate the utility of this library for profiling protease substrate specificity.

The effect of skin transplantation on tumor growth in mice

BACKGROUND

Skin allograft is an immunostimulant. Skin allograft activates effector arms of the immune system including the cytotoxic T lymphocytes, activated macrophages, and natural killer cells. These cells may be involved in the destruction of tumor cells.

METHODS

Balb/c mice were divided into the study (n = 10) and control (n = 10) groups. Alloskin grafts 1 cm in diameter from the backs of Swiss albino mice were placed on the backs of balb/c mice (study group). The same size autoskin grafts from the backs of other balb/c mice were used for the control group. Fourteen days after grafting, we inoculated 1,000 Ehrlich ascites tumor cells intraperitoneally into both groups. Two days after tumor inoculation, we used secondary allografts and autografts (which were about 2 to 3 mm in diameter) for the same groups. We followed up graft survival and animal survival in both groups.

RESULTS

All 10 of the autografted mice died between the 18th and 25th days owing to malignancy. In the allografted group, 2 mice died (1 on day 17 and the other on day 23). Allograft rejection had not occurred in these 2 mice at the time of their death. The other 8 mice in the same group rejected allograft, on average within 9 days (9+/-3, median 8). These 8 mice were alive and without apparent health problems during the 4 months of follow-up.

CONCLUSION

Allo-skin graft rejection may help rejection of tumor cells and may be of use in immunotherapy of cancer.

[Removal of bone cement with laser]

In operations requiring replacement of cemented endoprothesis, the removal of both the prosthesis and the cement is often difficult as the cement adheres strongly to the bone. Mechanical removal frequently results in fenestration or traumatisation of the bone. The aim of non-contact removal of polymethylmethacrylate (PMMA) with the laser, is to access normally inaccessible regions while inflicting a minimum amount of damage to the bone substance. The much cited cw or superpulsed CO2-laser cannot be used clinically, due to the thermal stressing of the bone. The paper shows spectra of PMMA with and without dopants, e.g. Tinuvin as UV absorber, optical staining with a high-pressure mercury lamp at lambda = 275 +/- 25 nm, lambda = 350 +/- 25 nm and various radiation times, as well as with an excimer laser lambda = 248 nm, FWHM 20 ns, and ablation measurements were made with the following lasers: excimer laser, Lambda Physics, EMG 102, FWHM 25 ns, lambda = 351 nm, excimer laser, Technolas, MAX 10, FWHM 60 ns, lambda = 308 nm, and a pulsed CO2 laser from PSI, lambda = 9.2 and 10.6 microns, FWHM 130 and 65 microseconds, pulse peak power 3.8 and 7.7 kW. The excimer laser, pulse length less than 100 ns, is unsuitable for clinical use because the required removal rate cannot be achieved either with doped PMMA or with pure PMMA. More promising results have been obtained with the pulsed (microseconds range) CO2 laser which has a removal rate of up to 30 times that of the above-mentioned excimer laser, with significantly lower thermal stressing of the bone than with the cw or super pulsed CO2 laser.

Blue sclerae and keratoglobus. Ocular signs of a systemic connective tissue disorder

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