In-vitro antibacterial activity of selected medicinal plants from Longisa region of Bomet district, Kenya.

BACKGROUND: Current strategies to overcome the global problem of antimicrobial resistance include research in finding new and innovative antimicrobials from plants. This study was carried out to determine the antibacterial activity of plant extracts of Olea africana stem-bark, Psidium guajava leaves, Vernonia amygdalina leaves, Lantana camara leaves and Mangifera indica leaves which are used in folklore medicine to treat infections of microbial origin in Longisa region of Bomet District, Kenya. METHODS: Methanol extracts were derived and screened. Standard cultures of Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Staphylococcus aureus ATCC 25923 were used in the study. The antibacterial tests used were the agar well diffusion assays at concentration 1 gm/ml. Minimum Inhibition Concentration (MIC) was determined in the plant extract that showed some efficacy against the tested microorganisms. Gentamicin (10 microg) was used as a positive control. RESULTS: The methanol extracts showed weak antibacterial activity against the study organisms compared to Gentamicin. All extracts exhibited a significant bactericidal activity against S. aureus while L. camara and V. amygdalina lacked efficacy against P.aeruginosa and E. coli. O. africana and P. guajava presented the lowest MIC against S.aureus (62.5 mg/ml and 250 mg/ml respectively P. guajava and M. indica showed analogous MICs against P.aeruginosa (250 mg/ml). P. guajava exhibited a better MIC against E.coli (500 mg/ml). CONCLUSIONS: This in-vitro study corroborated the antimicrobial activity of the selected plants used in folklore medicine. The plants could be potential sources of new antimicrobial agent.

Drug sensitivity patterns of bacterial isolates from septic post-operative wounds in a regional referral hospital in Uganda.

BACKGROUND: Wound infections have been a problem in the field of surgery for a long time. Advances in control of infections have not completely eradicated this problem because of development of drug resistance. Antimicrobial resistance can increase complications and costs associated with procedures and treatment. OBJECTIVE: A study was carried out on drug sensitivity patterns of bacterial isolates from septic postoperative wounds in Jinja hospital, Uganda. This study was designed to determine the distribution of bacterial pathogens isolated from septic post-operative wounds and their antimicrobial susceptibility patterns. METHOD: Specimens of pus swabs were collected aseptically and analysed in the laboratory. Colony characteristics and Grams technique were used to differentiate the organisms. Biochemical tests were done to confirm the species of the organisms. Sensitivity testing was done on the isolates using the disk diffusion method. RESULTS: Pathogenic bacteria were recovered from 58.5% of the specimens. The isolates were: S.aureus (45.1%), Coliforms (16.9%), Proteus mirabilis (11.3%), P.aeruginosa (9.9%), Klebsiella pneumoniae (7.0%) and Enterobacter spp (2.82%). Most of the organisms were sensitive to gentamicin, ciprofloxacin and ceftazidime. There was resistance to ampicillin, amoxycillin and chloramphenicol. Staphylococcus aureus was generally sensitive to gentamicin (87.5%), ciprofloxacin (68.7%) and methicillin (75%), but resistant to erythromycin (56.2%) and ampicillin (97%). Most of the gram-negative bacteria isolated (Coliforms, P.aeruginosa, E.coli, Proteus mirabilis, and Klebsiella pneumoniae) were sensitive to Ciprofloxacin, Gentamicin and Ceftazidime but resistant to Ampicillin, Amoxycillin and Chloramphenicol. Methicillin-resistant Staphylococcus aureus (MRSA) strains formed 25% of this species. Pseudomonas aeruginosa was sensitive to gentamicin (87.5%) and ceftazidime (85.7%) but showed resistance to ciprofloxacin (57.2%). Some organisms e.g. S.aureus, Pseudomonas aeruginosa and Proteus mirabilis exhibited multi-drug resistance to the antibiotics tested. CONCLUSION: Since a high proportion of samples had positive cultures, infection control is recommended as a strategy to minimise spread of resistant organisms. It is recommended that gentamicin, ciprofloxacin and ceftazidime be used in preference to ampicillin and amoxycillin for treatment of septic wounds. There is need to develop national surveillance of antibiotic- resistant organisms.

The sensitivities to first-line antibiotic therapy of the common urinary tract bacterial infections detected in urine samples at a hospital in metropolitan Kampala (Uganda).

BACKGROUND: Urinary tract infections (UTIs) are among the most common human infections. Many urinary tract bacteria are capable of expressing drug resistance. Resistant bacteria may be present from the commencement of the infection or may develop during treatment. This study focused on the problem of antibiotic resistance to the first-line drugs that were used to treat patients presenting with urinary tract infections at Rubaga hospital in Kampala, Uganda. OBJECTIVES: The objective of this study was to isolate and identify the major bacterial pathogens of symptomatic and asymptomatic UTIs among patients at Rubaga hospital. Furthermore, the study sought to determine the antimicrobial susceptibility patterns of the major bacterial isolates to the first-line drugs used to treat UTIs at Rubaga hospital. METHODS: Urine samples were aseptically collected and examined microscopically and were microbiologically cultured on blood agar, nutrient agar and on MacConkey agar. The isolates obtained were then identified using standard tests and tested for antimicrobial sensitivity by the Kirby-Bauer technique. RESULTS: The isolated pathogens included Escherichia coli (10.9%), Staphylococcus (31.9%), Streptococcus (9.2%), Klebsiella species (21.0%) and Proteus species (10.1%). 20 (16.8%) of the isolates were lactose fermenting gram-negative rods that were also indole-negative. These isolates were termed 'unclassified coliforms' in this study but were probably Enterobacter species. On antimicrobial susceptibility testing, all the gram-negative isolates were significantly resistant to amoxycillin, cotrimoxazole, erythromycin, and to nalidixic acid; but were susceptible to nitrofurantoin. Among the gram-negative isolates, only Klebsiella species were significantly resistant (p<0.05) to ciprofloxacin. The gram-positive cocci were susceptible to amoxycillin, ciprofloxacin, and to erythromycin but resistant to cotrimoxazole and nalidixic acid. Unlike the Staphylococcus species that were significantly resistant to nitrofurantoin, Streptococcus species were moderately susceptible to the drug. CONCLUSION: The common urinary tract bacteria detected in Rubaga hospital in Uganda were most sensitive to Ciprofloxacin and Nitrofurantoin.

Drug Sensitivity Patterns of Bacterial Isolates from Septic Post-Operative Wounds in a Regional Referral Hospital in Uganda

Background: Wound infections have been a problem in the field of surgery for a long time. Advances in control of infections have not completely eradicated this problem because of development of drug resistance.Antimicrobial resistance can increase complications and costs associated with procedures and treatment. Objective: A study was carried out on drug sensitivity patterns of bacterial isolates from septic postoperative wounds in Jinja hospital; Uganda.This study was designed to determine the distribution of bacterial pathogens isolated from septic post-operative wounds and their antimicrobial susceptibility patterns. Method: Specimens of pus swabs were collected aseptically and analysed in the laboratory. Colony characteristics and Grams technique were used to differentiate the organisms. Biochemical tests were done to confirm the species of the organisms. Sensitivity testing was done on the isolates using the disk diffusion method. Results: Pathogenic bacteria were recovered from 58.5of the specimens.The isolates were: S.aureus (45.1); Coliforms (16.9); Proteus mirabilis (11.3); P.aeruginosa (9.9); Klebsiella pneumoniae (7.0) and Enterobacter spp (2.82). Most of the orga- nisms were sensitive to gentamicin; ciprofloxacin and ceftazidime.There was resistance to ampicillin; amoxycillin and chloramphenicol. Staphylococcus aureus was generally sensitive to gentamicin (87.5); ciprofloxacin (68.7) and methicillin (75); but resistant to erythromycin (56.2) and ampicillin (97). Most of the gram-negative bacteria isolated (Coliforms; P.aeruginosa ; E.coli ; Proteus mirabilis ; and Klebsiella pneumoniae ) were sensitive to Ciprofloxacin; Gentamicin and Ceftazidime but resistant to Ampicillin;Amoxycillin and Chloramphenicol. Methicillin-resistant Staphylococcus aureus (MRSA) strains formed 25of this species. Pseudomonas aeruginosa was sensitive to gentamicin (87.5) and ceftazidime (85.7) but showed resistance to ciprofloxacin (57.2). Some organisms e.g. S.aureus; Pseudomonas aeruginosa and Proteus mirabilis exhibited multi-drug resistance to the antibiotics tested. Conclusion: Since a high proportion of samples had positive cultures; infection control is recommended as a strategy to minimise spread of resistant organisms. It is recommended that gentamicin; ciprofloxacin and ceftazidime be used in preference to ampicillin and amoxycillin for treatment of septic wounds.There is need to develop national surveillance of antibiotic- resistant organisms

The Sensitivities to First-Line Antibiotic Therapy of the Common Urinary Tract Bacterial Infections Detected in Urine Samples at a Hospital in Metropolitan Kampala (Uganda)

Background: Urinary tract infections (UTIs) are among the most common human infections. Many urinary tract bacteria are capable of expressing drug resistance. Resistant bacteria may be present from the commencement of the infection or may develop during treatment. This study focused on the problem of antibiotic resistance to the first-line drugs that were used to treat patients presenting with urinary tract infections at Rubaga hospital in Kampala; Uganda. Objectives: The objective of this study was to isolate and identify the major bacterial pathogens of symptomatic and asymptomatic UTIs among patients at Rubaga hospital. Furthermore; the study sought to determine the antimicrobial susceptibility patterns of the major bacterial isolates to the first-line drugs used to treat UTIs at Rubaga hospital. Methods: Urine samples were aseptically collected and exami- ned microscopically and were microbiologically cultured on blood agar; nutrient agar and on MacConkey agar. The isolates obtained were then identified using standard tests and tested for antimicrobial sensitivity by the Kirby-Bauer technique. Results: The isolated pathogens included Escherichia coli (10.9); Staphylococcus (31.9); Streptococcus (9.2); Klebsiella species (21.0) and Proteus species (10.1). 20 (16.8) of the isolates were lactose fermenting gram-negative rods that were also indole-negative. These isolates were termed 'unclassified coliforms' in this study but were probably Enterobacter species. On antimicrobial susceptibility testing; all the gram-negative isolates were significantly resistant to amoxycillin; cotrimoxazole; erythromycin; and to nalidixic acid; but were susceptible to nitrofurantoin. Among the gram-negative isolates; only Klebsiella species were significantly resistant (p0.05) to ciprofloxacin. The gram-positive cocci were susceptible to amoxycillin; ciprofloxacin; and to erythromycin but resistant to cotrimoxazole and nalidixic acid. Unlike the Staphylococcus species that were significantly resistant to nitrofurantoin; Streptococcus species were moderately susceptible to the drug. Conclusion: The common urinary tract bacteria detected in Rubaga hospital in Uganda were most sensitive to Ciprofloxacin and Nitrofurantoin

Drug sensitivity of trypanosome populations from cattle in a peri-urban dairy production system in Uganda.

Cattle from 50 farms in Mukono County, Uganda, were monitored for trypanosomes every second month over an 18-month period (1995-1996) by mini-anion exchange chromatography and haematocrit centrifugation techniques. Eighteen trypanosome isolates collected from cattle during this period were characterised in cattle, goats and mice for their sensitivity to homidium, isometamidium and diminazene; 10 of the isolates were selected randomly, 8 were from animals that had the highest serum isometamidium concentrations at the time the isolates were collected. All the isolates contained only Trypanosoma brucei and/or T. vivax. In nai;ve Boran (Bos indicus) cattle the isolates exhibited low pathogenicity and were sensitive to diminazene aceturate at 3.5 mg/kg body weight (bw) and isometamidium chloride at 0.5 mg/kg bw. In goats, 5 of 8 isolates were highly pathogenic, producing clinical signs indicative of central nervous system involvement within 60 days of infection; all such isolates contained T. brucei. However, all 8 populations were sensitive in goats to diminazene aceturate at 3.5 mg/kg bw. In contrast, 4 populations were refractory to treatment with isometamidium chloride at 0.5 mg/kg bw in at least 1 out of 3 goats each. Furthermore, 5 populations were refractory to treatment with homidium chloride at 1.0 mg/kg bw in a minimum of 2 out of 3 goats each. In mice, the 50% curative dose values for 11 Mukono isolates that contained T. brucei ranged from 0.30 to 1.89 mg/kg bw for diminazene aceturate, from 0.02 to 0.17 mg/kg bw for isometamidium chloride and from 0.90 to 4.57 mg/kg bw for homidium chloride. Thus, by comparison to reference drug-sensitive populations, all the stabilates were highly sensitive to diminazene and isometamidium, while some expressed low levels of resistance to homidium.

Screening extracts of Zanthoxylum chalybeum and Warburgia ugandensis for activity against measles virus (Swartz and Edmonston strains) in vitro.

A large proportion of the population in Uganda still relies on the use of plant extracts for treatment of various ailments. This study tested the claimed efficacy of some plants in the treatment of measles. In vitro antiviral assays were performed on extracts of two medicinal plants (Warburgia ugandensis and Zanthoxylum chalybeum) using measles virus (Edmonston and Swartz strains) as the test organisms. The assays performed were the neutralisation tests and the plaque reduction assays. Of the two plants Z. chalybeum had demonstrable in vitro antiviral activity in the seed extracts (titer reduction factor [TRF]: 100, for the ethanolic extract). The in vitro antiviral activity of the seed extracts was demonstrated to be due to compound 27-135D (TRF=1000), which was characterized by (1)H-NMR spectroscopy as the alkaloid skimmianine. Skimmianine had minimal toxicity to VERO cell lines. The petroleum ether extracts and the ethanolic extracts of Warburgia ugandensis had no inhibitory effect on cytopathic effect (CPE) formation, especially at the maximal non-toxic dose (MNTD). The extracts of W. ugandensis were highly toxic to VERO cell lines. The TRF values for the stem bark extracts of W. ugandensis were: water extract, 10; ethanolic extract, 1; fraction 27-163D, 100., which were regarded to be too low. Seed extracts of Z.chalybeum therefore probably cure measles due to the antiviral effect of skimmianine. It is not clear how extracts of W. ugandensis produce a beneficial response in measles disease, if at all.

Cytotoxic and in vitro trypanocidal activities of a sesquiterpene derived from a Ugandan Medicinal plant

Trypanosomiasis is arguably the most important disease of man and his domesticated animals in the tropics. There are few compounds available for its treatment. This has exacerbated the development of drug resistance. There is therefore urgent need to search for newer compounds to treat this important disease. Medicinal plants represent a potential source of the drugs. This paper reports a bioassay-guided study to search for possible biological activity (cytotoxic and trypanocidal) in two Ugandan medicinal plants. The methodology adopted was the so-called 'ping-pong' approach; involving phytochemical purification (column chromatography and preparative thin layer chromatography); alongside biological studies (cytotoxicity; antibacterial; trypanocidal and antifungal studies). Phytochemical investigations of Zanthoxylum chalybeum (seed) yielded a pure crystalline compound; 27-135D; which was characterised by HNMR as the alkaloid skimmianine. Studies on stem bark yielded three alkaloids 27-165A; 27-173A and 27-173B. All the above pure isolates; and the crude extracts of Z. chalybeum had neither biological activity nor cytotoxicity in the brine shrimp assay. A cytotoxic sesquiterpine; characterised as muzigadial; was isolated from W. ugandensis. It was highly toxic in the brine shrimp assay and also had in vitro trypanocidal activity against IL 3338 as well as Il1180; reference drug-resistant and drug-sensitive trypanosome strains respectively; comparable to diminazene aceturate and Geneticin (G418). Muzigadial also had antifungal activity against Candida albicans. It was concluded that the brine shrimp treatment of drug-resistant trypanosomosis

Antibacterial and antifungal activities of extracts of Zanthoxylum chalybeum and Warburgia ugandensis, Ugandan medicinal plants.

Measles is a killer disease of children in Uganda. The treatment of the disease is mainly directed at the secondary microbial infections. A large proportion of the population in Uganda still relies on the use of herbal remedies, which have been claimed to produce beneficial responses. In this study, the efficacy of Warburgia ugandensis and Zanthoxylum chalybeum against common bacteria and fungi was investigated. Bactericidal and antifungal assays were done using extracts derived from Z. chalybeum and W. ugandensis (agar well diffusion, disc diffusion and colony count assays). All extracts (ethanolic, petroleum ether and aqueous) of Z. chalybeum did not show antimicrobial activity. Phytochemical investigations of Zanthoxylum chalybeum (seed) yielded a pure crystalline alkaloid (27-135 D) which was characterized as skimianine based on (1)H-NMR spectroscopy and comparison with spectra of authentic samples. Skimmianine did not have antimicrobial activity in this test system. W. ugandensis water extracts elicited antibacterial activity against both Escherischia coli and Staphylococcus aureus in the agar well assay but not in the disc diffusion assay. Warburgia ugandensis water extracts and fraction 27-163 D also showed antifungal activity against Candida albicans. Chromatography of extracts of Warburgia ugandensis stem bark afforded compound 49-169 K, which was characterized as the sesquiterpine muzigadial (by (1)H-NMR spectroscopy), which did not show antibacterial activity but had antifungal activity against C. albicans. Therefore, the claimed efficacy of W. ugandensis could be attributable to antibacterial and antifungal activity of its components. Since Z. chalybeum extracts had neither antifungal nor antibacterial activities, its mode of action is unclear from these results.

Bioassay-guided studies on the cytotoxic and in vitro trypanocidal activities of a sesquiterpene (Muzigadial) derived from a Ugandan medicinal plant (Warburgia ugandensis).

Trypanosomosis is arguably the most important disease of man and his domesticated animals in the tropics. There are few compounds available for its treatment. This has exacerbated the development of drug resistance. There is therefore urgent need to search for newer compounds to treat this important disease. Medicinal plants represent a potential source of the drugs. This paper reports a bioassay-guided study to search for possible biological activity (cytotoxic and trypanocidal) in two Ugandan medicinal plants. The methodology adopted was the so-called 'ping-pong' approach, involving phytochemical purification (column chromatography and preparative thin layer chromatography), alongside biological studies (cytotoxicity, antibacterial, trypanocidal and antifungal studies). Phytochemical investigations of Zanthoxylum chalybeum (seed) yielded a pure crystalline compound, 27-135D, which was characterized by 'HNMR as the alkaloid skimmianine. Studies on stem bark yielded three alkaloids 27-165A, 27-173A and 27-173B. All the above pure isolates, and the crude extracts of Z. chalybeum had neither biological activity nor cytotoxicity in the brine shrimp assay. A cytotoxic sesquiterpine, characterized as muzigadial, was isolated from W. ugandensis. It was highly toxic in the brine shrimp assay and also had in vitro trypanocidal activity against IL 3338 as well as IL1180; reference drug-resistant and drug-sensitive trypanosome strains respectively, comparable to diminazene aceturate and Geneticin (G418). Muzigadial also had antifungal activity against Candida albicans. It was concluded that the brine shrimp assay might be a useful predictor of trypanocidal activity of plant extracts and that muzigadial may be potentially valuable in the treatment of drug-resistant trypanosomosis.