Acanthamoeba keratitis is a serious ocular problem and can cause blindness if not treated. This study was therefore performed to evaluate the effectiveness of eyedrop antibiotics on eight Acanthamoeba spp. isolates, of which four
were clinical isolates and the remaining four from the environment. Three different eyedrop antibiotics (neomycin, ciprofloxacin and gentamicin) currently available in the market and ready for use were tested. Cyst suspension from all strains were tested against eyedrop antibiotics, respectively. After 48 hours of incubation period, the solutions were filtered and the filtered membranes were put onto non-nutrient agar lawn with E. coli. The plates were examined daily for Acanthamoeba trophozoites under inverted microscope until day 14. Neomycin, ciprofloxacin and gentamicin were found
to be effective against Acanthamoeba spp. cysts for all test strains.
Key words: Acanthamoeba Keratitis, Eyedrop Antibiotics, Effectiveness
Some of Vibrio species is well known as pathogenic bacteria in aquaculture and the marine industry. Its infection is able to generate a massive outbreak and affect the fish population, especially for net caged fish such as seabass. This study was conducted to investigate the prevalence of Vibrio spp. isolated from seabass (Lates calcarifer) in Sri Tujuh Lagoon, Tumpat, Kelantan. Then, to determine the antibiotic resistance in Vibrio isolates. Polymerase chain reaction (PCR) was used to detect Vibrio species using specific primer VR169 and VR744 with estimation base pair size band, 597 bp and further identified by sequencing. On the other hand, antibiotic susceptibility tests were continued by using 13 types of antibiotics; kanamycin (K30), chloramphenicol (C30), neomycin (N10), ampicillin (AMP10), nitrofurantoin (F300), tetracycline (TE30), streptomycin (S10), norfloxacin (NOR10), ciprofloxacin (CIP5), nalidixic acid (NA30), gentamicin (CN10), doxycycline (DO30) and sulfamethoxazole (SXT100). As a result, 14 Vibrio isolates were identified, including Vibrio fluvialis (n=6), Vibrio parahaemolyticus (n=3), Vibrio harveyi (n=2) and each isolate for Vibrio vulnificus, Vibrio alginolyticus and Vibrio spp. The results showed that all isolates were sensitive to most antibiotics except ampicillin, neomycin and streptomycin. The MAR index value was ranging from 0 to 0.31. This study demonstrates the prevalence of Vibrio spp. in seabass and the report on multidrug resistance strains that could be of concern to the fish farmers. In addition, data from this study can be further used in fish disease management plans.
Diabetes mellitus is one of the most concerning conditions, and its chronic consequences are almost always accompanied by infection, oxidative stress, and inflammation. Reducing excessive reactive oxygen species and the wound's inflammatory response is a necessary treatment during the acute inflammatory phase of diabetic wound healing. Malva sylvestris extract (MS) containing nanofibers containing neomycin sulfate (NS) were synthesized for this investigation, and their impact on the healing process of diabetic wounds was assessed. Using Design Expert, the electrospinning process for the fabrication of NS nanofibers (NS-NF) was adjusted for applied voltage (X1), the distance between the needle's tip and the collector (X2), and the feed rate (X3) for attaining desired entrapment efficacy [EE] and average nanofiber diameter (ND). The optimal formulation can be prepared with 19.11 kV of voltage, 20 cm of distance, and a flow rate of 0.502 mL/h utilizing the desirability approach. All the selected parameters and responses have their impact on drug delivery from nanofibers. In addition, M. sylvestris extracts have been added into the optimal formulation [MS-NS-NF] and assessed for their surface morphology, tensile strength, water absorption potential, and in vitro drug release studies. The NS and MS delivery from MS-NS-NF has been extended for more than 60 h. M. sylvestris-loaded nanofibers demonstrated superior antibacterial activity compared to plain NS nanofibers. The scaffolds featured a broad aspect and a highly linked porous fibrous network structure. Histomorphometry study and the in vitro scratch assay demonstrate the formulation's efficacy in treating diabetic wound healing. The cells treated with MS-NS-NF in vivo demonstrated that wound dressings successfully reduced both acute and chronic inflammations. To improve the healing of diabetic wounds, MS-NS-NF may be regarded as an appropriate candidate for wound dressing.
Six Campylobacter jejuni clinical isolates were examined for the occurrence of plasmids in association with antibiotic resistances as well as conjugal transfer. All the isolates were found to carry three similar plasmids of 78 kb, 12.6 kb and 3.3 kb in size. Multiple resistance to at least three of the antibiotics tested was observed with resistance to tetracycline most common. En bloc transfer of donor resistances at frequencies ranging from 10(-8) to 10(-4) were seen in all but one of the isolates during conjugation. The conjugal transfer of erythromycin, neomycin and streptomycin were observed to occur at frequencies similar to that of chloramphenicol, kanamycin and tetracycline. In isolate ABA94, three different antibiotic resistance phenotypes of the transconjugants were seen. In addition to en bloc transfer of the donor resistances, in approximately 10% of the transconjugants the streptomycin resistance was lost although these transconjugants carried the donor complement of three plasmids. In a further 1% of the transconjugants, resistance to kanamycin only was detected and these transconjugants did not carry any plasmids.
Antimicrobial resistance (AMR) has become a major problem worldwide with significance public health impact in both animal and human populations. Staphylococcus aureus (S. aureus) is a common pathogen in domestic livestock and Escherichia coli (E. coli) is a normal flora in the gut and these organisms are considered as effective indicators for AMR surveillance. Increased in antimicrobial resistance of these bacteria in veterinary medicine leads to difficulties in choosing effective antibiotics to treat diseases they caused. This study aimed to evaluate the susceptibility of S. aureus and E. coli isolated from dairy goats in selected farms located in Selangor, Malaysia against different antibiotics. Milk and faecal samples were collected from 36 dairy goats and samples were prepared for the isolation of S. aureus and E. coli isolates respectively. The isolates were subjected to antibiotic susceptibility test. All 11 (100%) E. coli isolates showed resistance to amoxicillin and penicillin while 3 (27%) of the 11 S. aureus isolates, showed resistance towards the same class of antibiotic. Both S. aureus and E. coli isolates showed high susceptibility to four antibiotics, namely trimethoprim-sulfamethazole, neomycin, tetracycline and enrofloxacin. This study provided information regarding the antibiotic resistance of S. aureus and E. coli in relation to the antimicrobial usage practice in selected dairy goat farms located in Selangor, Malaysia.
Acanthamoeba keratitis is a serious infection with blinding consequences and often associated with contact lens wear. Early diagnosis, followed by aggressive topical application of drugs, is a prerequisite in successful treatment, but even then prognosis remains poor. Several drugs have shown promise, including chlorhexidine gluconate; however, host cell toxicity at physiologically relevant concentrations remains a challenge. Nanoparticles, subcolloidal structures ranging in size from 10 to 100 nm, are effective drug carriers for enhancing drug potency. The overall aim of the present study was to determine whether conjugation with gold nanoparticles enhances the antiacanthamoebic potential of chlorhexidine. Gold-conjugated chlorhexidine nanoparticles were synthesized. Briefly, gold solution was mixed with chlorhexidine and reduced by adding sodium borohydride, resulting in an intense deep red color, indicative of colloidal gold-conjugated chlorhexidine nanoparticles. The synthesis was confirmed using UV-visible spectrophotometry that shows a plasmon resonance peak of 500 to 550 nm, indicative of gold nanoparticles. Further characterization using matrix-assisted laser desorption ionization-mass spectrometry showed a gold-conjugated chlorhexidine complex at m/z 699 ranging in size from 20 to 100 nm, as determined using atomic force microscopy. To determine the amoebicidal and amoebistatic effects, amoebae were incubated with gold-conjugated chlorhexidine nanoparticles. For controls, amoebae also were incubated with gold and silver nanoparticles alone, chlorhexidine alone, neomycin-conjugated nanoparticles, and neomycin alone. The findings showed that gold-conjugated chlorhexidine nanoparticles exhibited significant amoebicidal and amoebistatic effects at 5 μM. Amoebicidal effects were observed by parasite viability testing using a Trypan blue exclusion assay and flow-cytometric analysis using propidium iodide, while amoebistatic effects were observed using growth assays. In contrast, chlorhexidine alone, at a similar concentration, showed limited effects. Notably, neomycin alone or conjugated with nanoparticles did not show amoebicidal or amoebistatic effects. Pretreatment of A. castellanii with gold-conjugated chlorhexidine nanoparticles reduced amoeba-mediated host cell cytotoxicity from 90% to 40% at 5 μM. In contrast, chlorhexidine alone, at similar concentrations, had no protective effects for the host cells. Similarly, amoebae treated with neomycin alone or neomycin-conjugated nanoparticles showed no protective effects. Overall, these findings suggest that gold-conjugated chlorhexidine nanoparticles hold promise in the improved treatment of A. castellanii keratitis.
Overuse of antimicrobials in livestock health and production beyond therapeutic needs has been highlighted in recent years as one of the major risk factors for the acceleration of antimicrobial resistance (AMR) of bacteria in both humans and animals. While there is an abundance of reports on AMR in clinical isolates from humans, information regarding the patterns of resistance in clinical isolates from animals is scarce. Hence, a situational analysis of AMR based on clinical isolates from a veterinary diagnostic laboratory was performed to examine the extent and patterns of resistance demonstrated by isolates from diseased food animals. Between 2015 and 2017, 241 cases of diseased livestock were received. Clinical specimens from ruminants (cattle, goats and sheep), and non-ruminants (pigs and chicken) were received for culture and sensitivity testing. A total of 701 isolates were recovered from these specimens. From ruminants, Escherichia coli (n = 77, 19.3%) predominated, followed by Staphylococcus aureus (n = 73, 18.3%). Antibiotic sensitivity testing (AST) revealed that E. coli resistance was highest for penicillin, streptomycin, and neomycin (77-93%). In addition, S. aureus was highly resistant to neomycin, followed by streptomycin and ampicillin (68-82%). More than 67% of E. coli isolates were multi-drug resistant (MDR) and only 2.6% were susceptible to all the tested antibiotics. Similarly, 65.6% of S. aureus isolates were MDR and only 5.5% were susceptible to all tested antibiotics. From non-ruminants, a total of 301 isolates were recovered. Escherichia coli (n = 108, 35.9%) and Staphylococcus spp. (n = 27, 9%) were the most frequent isolates obtained. For E. coli, the highest resistance was against amoxicillin, erythromycin, tetracycline, and neomycin (95-100%). Staphylococcus spp. had a high level of resistance to streptomycin, trimethoprim/sulfamethoxazole, tetracycline and gentamicin (80-100%). The MDR levels of E. coli and Staphylococcus spp. isolates from non-ruminants were 72.2 and 74.1%, respectively. Significantly higher resistance level were observed among isolates from non-ruminants compared to ruminants for tetracycline, amoxicillin, enrofloxacin, and trimethoprim/sulfamethoxazole.