A cross sectional study on antibiotic resistance pattern of Salmonella typhi clinical isolates from Bangladesh

Objective:To investigate and compare the resistance and sensitivity of Salmonella typhi samples to commonly used antibiotics in three major divisions of Bangladesh and to evaluate the gradually developing resistance pattern.Methods:The antibiotic susceptibility of 70 clinical isolates collected from blood,sputum,urine and pus samples were identified by specific antisera and with standard biochemical tests.The patients were divided into 5 age groups.Susceptibility and resistance was also tested by KirbyBauer disc-diffusion method using 12 regularly used antibiotics.Results:Antibiotic susceptibility test demonstrated that 64.28%isolates of Salmonella typhi were multidrug resistant.Present study suggests that the clinical samples were mostly resistant against nalidixic acid with all age groups and in all three divisions with similar resistance pattern.Resistance is more common among adult people(30-40 years)and children(0-10 years).Salmonella typhi was mostly sensitive against gentamycin,chloramphenicol and ciprofloxacin.Conclusions:Although the population density of Dhaka region is markedly higher than Rajshahi and Chittagong regions,no significant difference in resistance pattern was found.The rate of multidrug resistance is a matter of concern.Physicians should reconsider before prescribing nalidixic acid and cefixime.Further molecular study is needed to reveal the genomic and proteomic basis of resistance.

Chemical Composition and Source Characterization of Hailstones in Dhaka, Bangladesh

A comprehensive analysis on the chemical composition and source apportionment of hailstone samples were conducted in Dhaka, Bangladesh. pH, electrical conductivity (EC), total dissolved solids (TDS), water soluble ions (Na+, K+, Ca2+, Mg2+, Cl-, SO42-, NO3-, HCO3-) and trace metals (Zn, Fe, Cu, Mn) of hailstone were determined. The result revealed that the average pH, EC, TDS were 6.95 ± 0.54, 356.3 ± 150.6 μS·cm-1 and 17.5 ± 2.89 mg·L-1, respectively. The water soluble ions followed the order: Ca2+ > Cl-1 > SO42- > HCO3- > Na+ > Mg2+ > K+ > NO3-. The concentrations of trace metals ranged in order with Zn > Fe > Cu, while the concentration of Mn was below detection limit. Sodium adsorption ratio (SAR) was 0.20 ± 0.09 meqL-1 which indicates it is benign to plants and safe for irrigation. The order of neutralization factor (calculated with average concentrations) found in hailstone was NFCa(1.16) > NFMg (0.36) > NFK(0.32) which were originated from earth crust. Notable correlation was found in between soil tracers Ca2+ and Mg2+ (r = 0.87), indicating their common source dust. Enrichment factor analysis revealed that Ca2+, Mg2+ and K+ are mainly from crust, whereas NO3- and SO42- are mainly attributable to anthropogenic origins. Further source contribution analysis revealed that anthropogenic actions accounted for 99.2% of total NO3- and 89.6% of total SO42-, while 99.2% of total Ca2+ and 95% Mg2+ were from crustal source.