Water,
sanitation, and hygiene interventions have varying effectiveness
in reducing fecal contamination in the domestic environment; delivering
them in combination could yield synergies. We conducted environmental
assessments within a randomized controlled trial in Bangladesh that
implemented single and combined water treatment, sanitation, handwashing
(WSH) and nutrition interventions (WASH Benefits, NCT01590095). After
one and two years of intervention, we quantified fecal indicator bacteria
in samples of drinking water (from source or storage), child hands,
children’s food and sentinel objects. In households receiving
single water treatment interventions, Escherichia coli prevalence in stored drinking water was reduced by 50% and concentration
by 1-log. E. coli prevalence in food was reduced
by 30% and concentration by 0.5-log in households receiving single
water treatment and handwashing interventions. Combined WSH did not
reduce fecal contamination more effectively than its components. Interventions
did not reduce E. coli in groundwater, on child hands
and on objects. These findings suggest that WSH improvements reduced
contamination along the direct transmission pathways of stored water
and food but not along indirect upstream pathways. Our findings support
implementing water treatment and handwashing to reduce fecal exposure
through water and food but provide no evidence that combining interventions
further reduces exposure.
The discovery of novel biocontrol agents requires the continuous scrutiny of native microorganisms to ensure that they will be useful on a regional scale. The goal of the present work was to discover novel antagonistic bacteria against
Fusarium oxysporum
ff. spp.
lycopersici
race 3 (
Fol
R3) and
radicis-lycopersici
(
Forl
) causing
Fusarium
wilt disease and
Fusarium
crown and root rot of tomatoes, respectively. High-throughput liquid antagonism screening of 1,875 rhizospheric bacterial strains followed by dual confrontation assays in 96-well plates was used to select bacteria exhibiting > 50% fungal growth inhibition. In a second dual confrontation assay in 10-cm Petri dishes, bacteria showing > 20%
Fol
R3 or
Forl
growth inhibition were further screened using a blood hemolysis test. After discarding β-hemolytic bacteria, a seedling antagonistic assay was performed to select five potential antagonists. A phylogenetic analysis of 16S rRNA identified one strain as
Acinetobacter calcoaceticus
(
Ac
DB3) and four strains as members of the genus
Bacillus
(
B. amyloliquefaciens Ba
MA26,
Bacillus siamensis Bsi
DA2,
B. subtilis Bs
TA16 and
B. thuringiensis Bt
MB9). Greenhouse assays demonstrated that
Bs
TA16 and
Ac
DB3 were the most promising antagonists against
Fol
R3 and
Forl
, respectively. Pathogen biocontrol and growth promotion mechanisms used by these bacteria include the production of siderophores, biofilm, proteases, endoglucanases and indole acetic acid, and phosphate solubilization. These five bacteria exerted differential responses on pathogen control depending on the tomato hybrid, and on the growth stage of tomatoes. We report for the first time the use of an
Acinetobacter calcoaceticus
isolate (
Ac
DB3) to control
Forl
in tomato under greenhouse conditions.
Present study was carried out for the microbiological evaluation of allogeneic bone processed from femoral heads. A total 60 bacterial isolates comprising five different species including Streptococcus spp., Staphylococcus spp., Klebsiella spp., Bacillus spp., and Pseudomonas spp. were characterized based on their cultural and biochemical characteristics. Average bioburden was ranged from 5.7 × 101 to 3.9 × 104 cfu/gm. The majority (81.7%) of the microbial contaminants were detected as Gram positive with the predominant organism being skin commensal coagulase negative Staphylococci (43.3%). Antimicrobial resistance was evaluated by the activities of 14 broad and narrow spectrum antibiotic discs. Comparing the overall pattern, marked resistance was noted against Penicillin and Amoxicillin 100% (60/60). The most effective single antibiotics were Gentamicin, Tobramycin, and Ofloxacin which were bactericidal against 100% (60/60) isolates. Multidrug resistance (MDR) was confirmed in 70% (42/60) of the samples. Among them, the most prevalent antibiotypes were Penicillin, Amoxicillin, Oxacillin, Polymyxin, and Cefpodoxime (80% of total MDR). The study results revealed higher contamination rate on bone allografts and recommend the implementation of good tissue banking practices during tissue procurement, processing, and storage in order to minimize the chances of contamination.
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