Anti-enteric bacterial activity and phytochemical analysis of the seed kernel extract of Mangifera indica Linnaeus against Shigella dysenteriae (Shiga, corrig.) Castellani and Chalmers.

OBJECTIVE: To evaluate the phytochemical and anti-bacterial efficacy of the seed kernel extract of Mangifera indica (M. indica) against the enteropathogen, Shigella dysenteriae (S. dysenteriae), isolated from the diarrhoeal stool specimens. METHODS: The preliminary phytochemical screening was performed by the standard methods as described by Harborne. Cold extraction method was employed to extract the bioactive compounds from mango seed kernel. Disc diffusion method was adopted to screen antibacterial activity. Minimum inhibitory concentration (MIC) was evaluated by agar dilution method. The crude extracts were partially purified by thin layer chromatography (TLC) and the fractions were analyzed by high performance thin layer chromatography (HPTLC) to identify the bioactive compounds. RESULTS: Phytochemical scrutiny of M. indica indicated the presence of phytochemical constituents such as alkaloids, gums, flavanoids, phenols, saponins, steroids, tannins and xanthoproteins. Antibacterial activity was observed in two crude extracts and various fractions viz. hexane, benzene, chloroform, methanol and water. MIC of methanol fraction was found to be (95±11.8) µg/mL. MIC of other fractions ranged from 130-380 µg/mL. CONCLUSIONS: The present study confirmed that each crude extracts and fractions of M. indica have significant antimicrobial activity against the isolated pathogen S. dysenteriae. The antibacterial activity may be due to the phytochemical constituents of the mango seed kernel. The phytochemical tannin could be the reason for its antibacterial activity.

Antimicrobial susceptibility of Shigella flexneri and S. dysenteriae isolated from stool specimens of patients with bloody diarrhoea in Mwanza, Tanzania.

This study was conducted to determine frequency and pattern of antimicrobial susceptibility of Shigella species isolated from stool specimens collected from patients presenting with bloody diarrhoea in Mwanza City, Tanzania. The study was carried out from October 2004 to October 2005 and involved patients attending Sekou Toure Regional Hospital and Butimba Health Centre. Bacteriological cultures were done at the National Institute for Medical Research laboratory. A total of 489 patients (median age = 20 years) participated in the study and were able to provide stool specimens. Shigella species were isolated from 14% (69/489) of the stool specimens collected. Of the sixty nine strains of Shigella spp isolated, 62 (90%) were S. flexneri and 7 (10%) were S. dysenteriae. All Shigella strains isolated showed high resistance to ampicillin, tetracycline, trimethoprim-sulphamethoxazole and chloramphenicol, drugs commonly used for management of shigellosis in Tanzania. However all isolates were fully susceptible to ciprofloxacin, nalidixic acid, erythromycin, cefuroxime and gentamycin. S. flexneri showed resistance to amoxy-clavulanic_acid and azithromycin in 5% and 2% of isolates, respectively. None of the S. dysenteriae isolates were resistant to these two drugs. Entamoeba histolytica, Giardia lamblia and Schistosoma mansoni were microscopically detected in 16.5%, 4.4% and 5.3% of patients, respectively. These findings suggest that there is a need to carry out extensive susceptibility studies in different parts of the country with view of re-appraising the current guidelines for management of bloody diarrhoea in Tanzania.

Case management of a multidrug-resistant Shigella dysenteriae serotype 1 outbreak in a crisis context in Sierra Leone, 1999-2000.

From December 1999 to the end of February 2000, 4218 cases of dysentery were reported in Kenema district, southeastern Sierra Leone, by a Médecins Sans Frontières team operating in this region. Shigella dysenteriae serotype 1 was isolated from the early cases. The overall attack rate was 7.5% but higher among children under 5 years (11.2%) compared to the rest of the population (6.8%) (RR = 1.6; 95% CI 1.5-1.8). The case fatality ratio was 3.1%, and higher for children under 5 years (6.1% vs. 2.1%) (RR = 2.9; 95% CI 2.1-4.1). A case management strategy based on stratification of affected cases was chosen in this resource-poor setting. Patients considered at higher risk of death were treated with a 5 day ciprofloxacin regimen in isolation centres. Five hundred and eighty-three cases were treated with a case fatality ratio of 0.9%. Patients who did not have signs of severity when seen by health workers were given hygiene advice and oral rehydration salts. This strategy was effective in this complex emergency.

Predictors of serum retinol in children with shigellosis.

BACKGROUND: Low serum retinol can be useful as an indicator of depleted liver vitamin A stores, particularly in population-based studies. However, serum retinol concentrations decrease transiently during infection, independent of any changes in liver stores. The magnitude of the decrease in serum retinol is often proportional to indicators of disease severity. OBJECTIVE: We examined the relation of serum retinol in children with culture-positive shigellosis with severity of illness, anthropometric indicators of nutritional status, urinary retinol excretion, and serum concentrations of C-reactive protein, alpha1-acid glycoprotein, retinol binding protein, and transthyretin. DESIGN: This was a prospective study assessing the clinical and laboratory measurements at admission and recovery of 90 children with dysentery (66 with shigellosis) hospitalized in Bangladesh. RESULTS: Serum retinol concentrations were low at admission but were significantly greater at discharge even though no vitamin A supplements were given during the illness (0.36 +/- 0.22 compared with 1.15 +/- 0.50 micromol/L, P < 0.001). Serum retinol concentrations were lower in children with Shigella dysenteriae type 1 infection than in children with shigellosis due to less virulent strains of Shigella. Low serum retinol was independently associated with S. dysenteriae type 1, high serum C-reactive protein concentrations, and low weight-forage in multiple regression analysis. CONCLUSIONS: This study showed that shigellosis was associated with a significant, transient decrease in serum retinol concentrations of approximately 0.8 micromol/L, and that this change was significantly associated with severity of disease and poor underlying nutritional status, particularly low weight-for-age.

[Short-term ciprofloxacin treatment of bacillary dysentery due to Shigella dysenteriae type 1 in Rwandan refugees]. / Traitement court par la ciprofloxacine de la dysenterie bacillaire à Shigella dysenteriae type 1 chez des réfugiés Ruandais.

In 1994, an outbreak of dysentery caused by Shigella dysenteriae type I resistant to all public health antibiotics in vitro occurred among rwandan refugees in Zaïre. The only active antimicrobial agent available was ciprofloxacin. It was administered to hospitalized patients in a conventional 5-day schedule. To ration the supply for the benefit of the greatest number, a randomized blinded study was performed to compare the effectiveness of short-term treatment (1 g of ciprofloxacin in a single daily doses for 2 days) with that of the standard treatment (1 g of ciprofloxacin in two daily doses for 5 days). The study included 57 refugees over the age of 15 years with dysentery. Shigella dysenteriae type I was identified in 26 patients. Except for sex distribution, there was no significant difference in clinical and bacteriologic features of the two populations. Treatment failed in 12 cases, i.e., 7 of 29 patients who received the short-term treatment and 5 of 28 patients who received the standard treatment. Efficacy of ciprofloxacin was not dependent on the mode of treatment, taking into account clinical or bacteriologic criteria. These results indicated that the duration of ciprofloxacin treatment for dysentery caused by Shigella dysenteriae type 1 could be shortened to two days. Short-term treatment has several advantages. One is cost-effectiveness since fluoroquinolones are costly and scarce. Another is to allow treatment of a greater number of patients by improving compliance.