Antibacterial Activity Against Multidrug-Resistant Clinical Isolates of Nine Plants from Chencha, Southern Ethiopia.

Background: The diminishing efficacy of antibiotics currently in use and the emergence of multidrug-resistant bacteria pose a grave threat to public health worldwide. Hence, new classes of antimicrobials are urgently required, and the search is continuing. Methods: Nine plants were chosen for the current work, which are collected from the highlands of Chencha, Ethiopia. Plant extracts containing secondary metabolites in various organic solvents were checked for antibacterial activity against type culture bacterial pathogens and MDR clinical isolates. The broth dilution technique was used to evaluate the minimum inhibitory and minimum bactericidal concentrations of highly active plant extracts, and time-kill kinetic and cytotoxic assays were performed using the most active plant extract. Results: Two plants (C. asiatica and S. marianum) were highly active against ATCC isolates. The EtOAc extract of C. asiatica produced the highest zone of inhibition ranging between 18.2±0.8-20.7±0.7 and 16.1±0.4-19.2±1.4 mm against Gram-positive and Gram-negative bacteria, respectively. The EtOH extract of S. marianum displayed zones of inhibition in the range of 19.9±1.4-20.5±0.7 mm against the type culture bacteria. The EtOAc extract of C. asiatica effectively curbed the growth of six MDR clinical isolates. The MIC values of C. asiatica against the Gram-negative bacteria tested were 2.5 mg/mL, whereas the corresponding MBC values were 5 mg/mL in each case. The MIC and MBC values were the lowest in the case of Gram-positive bacteria, ie, 0.65 and 1.25 mg/mL, respectively. A time-kill assay showed the inhibition of MRSA at 4 × MIC and 8 × MIC within 2 hours of incubation. The 24 h LD50 values of C. asiatica and S. marianum corresponding to Artemia salina were 3.05 and 2.75 mg/mL, respectively. Conclusion: Overall results substantiate the inclusion of C. asiatica and S. marianum as antibacterial agents in traditional medicines.

Evaluation of the performance of clinical predictors in estimating the probability of pulmonary tuberculosis among smear-negative cases in Northern Ethiopia: a cross-sectional study.

OBJECTIVES: To evaluate the performance of the predictors in estimating the probability of pulmonary tuberculosis (PTB) when all versus only significant variables are combined into a decision model (1) among all clinical suspects and (2) among smear-negative cases based on the results of culture tests. DESIGN: A cross-sectional study. SETTING: Two public referral hospitals in Tigray, Ethiopia. PARTICIPANTS: A total of 426 consecutive adult patients admitted to the hospitals with clinical suspicion of PTB were screened by sputum smear microscopy and chest radiograph (chest X-ray (CXR)) in accordance with the Ethiopian guidelines of the National Tuberculosis and Leprosy Program. Discontinuation of antituberculosis therapy in the past 3 months, unproductive cough, HIV positivity and unwillingness to give written informed consent were the basis of exclusion from the study. PRIMARY AND SECONDARY OUTCOME MEASURES: A total of 354 patients were included in the final analysis, while 72 patients were excluded because culture tests were not done. RESULTS: The strongest predictive variables of culture-positive PTB among patients with clinical suspicion were a positive smear test (OR 172; 95% CI 23.23 to 1273.54) and having CXR lesions compatible with PTB (OR 10.401; 95% CI 5.862 to 18.454). The regression model had a good predictive performance for identifying culture-positive PTB among patients with clinical suspicion (area under the curve (AUC) 0.84), but it was rather poor in patients with a negative smear result (AUC 0.64). Combining all the predictors in the model compared with only the independent significant variables did not really improve its performance to identify culture-positive (AUC 0.84-0.87) and culture-negative (AUC 0.64-0.69) PTB. CONCLUSIONS: Our finding suggests that predictive models based on clinical variables will not be useful to discriminate patients with culture-negative PTB from patients with culture-positive PTB among patients with smear-negative cases.

Antibacterial Activity of Honey against Methicillin-Resistant Staphylococcus aureus: A Laboratory-Based Experimental Study.

BACKGROUND: Antimicrobial drug resistance is one of the serious issues this world is facing nowadays, and increased cost of searching for effective antimicrobial agents and the decreased rate of new drug discovery have made the situation increasingly worrisome. OBJECTIVE: The aim of this study is to determine in vitro antibacterial activity of honey against methicillin-resistant Staphylococcus aureus isolates from wound infection. METHODS: An experimental study was conducted from May to November 2017. Methicillin resistance was detected using cefoxitin (30 µg) and oxacillin (1 µg) antibiotic discs. Different concentrations of honey (25-100% v/v) were tested against each type of clinical isolates obtained from wound infection. A preliminary sensitivity test was done to all types of honey by using disk diffusion while minimum inhibitory concentration and minimum bactericidal concentration were determined for the most potent honey by the broth dilution technique. All statistical analysis was performed by using Statistical Package for the Social Sciences version 20. RESULTS: In this study, 36 bacterial isolates were recovered from 50 specimens, showing an isolation rate of 72%. The predominant bacteria isolated from the infected wounds were Staphylococcus aureus (15, 41.7%). Among identified Staphylococcus aureus, methicillin resistance accounts for 10 isolates (27.8%). All isolates showed a high frequency of resistance to tetracycline. Four collected honey varieties exhibited antibacterial activity, while the strongest inhibitory activity was demonstrated by honey-2 at 75% v/v. The mean MIC and MBC of honey-2 ranged from 9.38 to 37.5% v/v. CONCLUSIONS: Tested honey has both a bacteriostatic and bactericidal activity. Among the tested honey, "honey-2" had high antibacterial potency than others.