Microbiological and kinetic detection of gram negative bacilli producing extended-spectrum- β-lactamases (esbl) in emergencies and reanimation units of university hospital center, Yalgadoouedraogo, Burkina Faso

Background: Epidemiology of extended-Spectrum- β-lactamases has become worldwide, and our aim was to establish the prevalence of isolates producer in university hospital center Yalgado OUEDRAOGO particularly in reanimation and emergencies units.Material and methods: Prospective study was drive during July 2009 to march 2012 in order to collect strains resisting to third generation of cephalosporin during diagnosis analysis of biological specimens. Susceptibility of bacteria to antimicrobial agents was evaluated by disc diffusion method. Production of extended-spectrum β-lactamases has been investigated by double disc diffusion and kinetic methods.Results: 259 isolates which resisted at least to one of third generation of cephalosporins were collected. Among them 188 (72, 58 %) were positive to synergy test by a double disc diffusion method. The MICs of ceftriaxone determined by E-test were under than 50kg/ml, 100kg/ml et 256kg/ml for respect 81,57°/° ; 55,26°/° et 39,74°/° of isolates. Hydrolyze of β-lactam ring by bacterial extract followed at spectrophotometer showed speeds running at 0 to 0,090UAb.mn-1 for both isolates. Extract of 171 bacterial strains positives to synergy test had hydrolyzed at least one of oxy-iminocephalosporins and were identified as producing extended- spectrum β-lactamases. Spices reported by this study were 99 Escherichia coli (57,89%) ; 28 Klebsisella pneumonia (16,37%) ; 15 Enterobactersp (8,77%) ; 19 Pseudomonas aeruginosa (11,11%) ; 4 Citrobactersp (2,33%) 2 Acinetobactersp (1,16%), 3 Proteus mirabilis (1,75%) and 1 Salmonella typhi (0,05%).Conclusion: This study showed that bacterial resistances by extended- spectrum β-lactamases are a reality in University Hospital center YalgadoOuedraogo. It calls about antibiotics prescription and hospital hygiene in order to reduce emergence and propagation of new resisting bacterial.Keywords: microbial and kinetic analysis, Gram negative bacilli, extended-Spectrum- β-lactamase, emergencies, reanimatio

First detection of bla TEM, SHV and CTX-M among Gram negative bacilli exhibiting extended spectrum β- lactamase phenotype isolated at University Hospital Center, Yalgado Ouedraogo, Ouagadougou, Burkina Faso

Resistance to a wide variety of common antimicrobials is observed among clinical strains designed as extended spectrum β-lactmase (ESBL)  producers. They produce enzymatic protein which inactivates efficiently oxyimino cephalosporin and constitutes a serious global health concern that has complicated treatment strategies. Many studies report high prevalence of ESBL producers among Gram negative bacilli. The aim of this work was to identify the presence of TEM, SHV and CTX-M families in thesestrains which were initially screened by phenotypic method. Gram negative bacilli resisting third or four generation cephalosporin were isolated during anti-biogram study. The presence of ESBL positivity was detected using the double disk synergy test. Minimal inhibitory concentrations (MICs) of ceftriazon for any strain were determined using E-test manufacturing protocol. Polymerase chain reaction (PCR) analysis for β-lactamase (bla) genes of TEM, SHV and CTX-M family was carried out using designed primers in 171 ESBL isolates producers. Among 259 Gram negative bacilli collected, 171 (66, 02%) exhibited ESBL producers’ profile. Urine samples constitute major source of ESBL producers. The highest prevalence of ESBL was observed in Escherichia coli (75, 50%). Among ESBL isolates producers, gene prevalence of bla-CTX-M (65, 49%) was highest, followed by bla-TEM (25, 73%) and bla-SHV (18, 71%) in the present study. The frequency of ESBL producing strains among clinical isolates has been steadily increased. Continual drug resistance surveillance and molecular characteristics of ESBL isolates are necessary to guide the appropriate and judicious antibiotic use.Key words: Extended spectrum β-lactamase (ESBL), double disk synergy test, blaTEM, blaSHV, blaCTX-M, PCR

Diapause disruption in Cirina butyrospermi Vuillet (Lepidoptera, Attacidae), the shea caterpillar, in Burkina Faso

The shea caterpillar Cirina butyrospermi is an important insect, highly valued as a human food item in Burkina Faso. However, its appearance is seasonal due to its univoltine cycle. This study therefore investigated the possibilities of breaking the nymphal diapause by changing the environmental factors and through the hormonal treatment of prepupae and pupae using bovine insulin and 20-hydroxyecdysone. Changes in humidity and temperature did not result in emergence, suggesting a mandatory nature of the diapause in C. butyrospermi. Injection of 20-hydroxyecdysone between 20 and 40 ng on 20 C. butyrospermi pupae resulted in 15.24 and 47.5% emergence, respectively. The incubation time varied between 40 and 38 days, respectively. No emergence was observed with the injection of bovine insulin. Dipping of C. butyrospermi larvae and pupae in solutions of 20-hydroxyecdysone resulted in similar rates of emergence between the two stages, with slight variations between individual doses: (1) for larvae, emergence was recorded at 10, 8, 5 and 15 mg/l with 98.5, 62.14, 25.73 and 24.16%, respectively; the incubation times varied from 39 days at 5 mg/l to 26 days at 20 mg/l; and (2) for pupae, emergence occurred between 5 and 20 mg/l, with the highest emergence rate recorded at 10, 8 and 15 mg/l with 94.58, 65.83 and 29.58%, respectively; the incubation times varied from 53 days for the lowest dose (5 mg/l) to 37 days (20 mg/l); the best emergence rate of 94.58% coincided with an incubation time of 43 days at 10 mg/l. No emergence was observed beyond 20 mg/l in both stages. Hormonal treatment with 20-hydroxyecdysone did not affect the fecundity of C. butyrospermi, with the fecundity of artificially emerging adults overlapping with that of naturally emerging adults. The emergence rate for both was similar. These results contribute to a better understanding of the physiology of this insect, constituting a breakthrough in its sustainable use as human food

Field dispersal of the parasitoid wasp Habrobracon hebetor (Hymenoptera: Braconidae) following augmentative release against the millet head miner Heliocheilus albipunctella (Lepidoptera: Noctuidae) in the Sahel

Pearl millet is one of the major staple food crops in Sub-Sahelian Africa, and the millet head miner (MHM) [Heliocheilus albipunctella] is its major pest, causing serious economic damage in the maturity period. We studied the dispersion patterns of the endogenous ectoparasitoid, Habrobracon hebetor (Hymenoptera: Braconidae), after augmentative releases in pearl millet fields for biological control of the MHM, in 2010 and 2011 in Burkina Faso and Niger. The parasitoids were released using 15 jute bags per release site. Parasitoid dispersion was indirectly monitored through weekly assessments of MHM parasitism by H. hebetor at different distances from release points (0, 3 and 5 km) and in control villages (15 km). Our findings indicate that the jute bags released approximately 900–1000 parasitoids per site over a period of three weeks. This initial parasitoid population led to higher parasitism of MHM larvae at the site of dissemination compared to farms at distances of 3 and 5 km. However, usually after five weeks, successive generations of H. hebetor dispersed up to 3 km, causing high levels of MHM larval mortality, which sometimes is similar to those of the release points. Based on these results, we recommend the release of parasitoids at sites spaced 3 km for timely and more efficient control of MHM populations

Modeling Evolution of Resistance by Maruca vitrata (Lepidoptera: Crambidae) to Transgenic Insecticidal Cowpea in Africa

We created a detailed model of the Maruca vitrata (F.) and cowpea [Vigna unguiculata (L.) Walp] system to study the possible evolution of resistance by the insect to transgenic insecticidal cowpea, which is under development. We focused on population dynamics and genetics in a region of west Africa. We simulated single-toxin and pyramided (two-toxin) cowpea and emphasized conservative, worst-case scenarios in our analysis. The results indicate that as long as a pyramided, transgenic cowpea can be developed, seed saving by farmers and reliance on natural refuge are not major problems for resistance management. Furthermore, it is possible that one or both toxins in the pyramid may not need to be high dose for evolution to be delayed significantly (>20 yr or 80 generations for resistance to become a concern if transgenic cowpea is deployed in areas where M. vitrata is endemic). If efforts are made to deploy transgenic cowpea only into the regions where M. vitrata is not endemic, then there is little to no concern with resistance emerging in the M. vitrata populatio

Feeding preferences of the legume pod borer Maruca vitrata (Lepidoptera: Crambidae) larvae and suitability of different flower parts for larval development

With the advent of transgenic Bacillus thuringiensis (Bt)-cowpea, there is a need to identify the feeding preferences of Maruca vitrata Fab. to determine in which component of the plant the expression of the toxin needs to be the highest to ensure the greatest efficacy of insecticidal Bt proteins. In the current study, we examined the feeding preferences of M. vitrata larvae in a naturally infested cowpea field. We also tested, in the laboratory, the suitability of different flower components for the larval development of M. vitrata. Our results indicate that in the field, all types of flowers, regardless of their age, were infested with M. vitrata larvae. The reproductive organs, in the flowers, were the preferred feeding diet for the larvae. Laboratory bioassays confirmed that the reproductive organs were the optimal tissues for M. vitrata larval development. The implications of these findings for transgenic Bt-cowpea are discussed

Augmentative on-farm delivery methods for the parasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae) to control the millet head miner Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) in Burkina Faso and Niger

Augmentative on-farm delivery methods for the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) to control the millet head miner (MHM) Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) were investigated in Burkina Faso from 2011 to 2012 and in Niger in 2012. Our findings indicate that 7 cm 9 10 cm jute bags containing 50 g of millet grains, 30 g of millet flour, 25 Corcyra cephalonica larvae and two mated H. hebetor females are the most effective option for on-farm delivery of the parasitoid. The parasitoid progeny started emerging from the bags eight days after confinement and 57–71 parasitoid adults emerged from each bag. Using the methods we developed, over 90 %parasitism of MHM larvae was achieved in millet farms. The implications of these findings for a large extension of MHM biocontrol program are discussed

How do Service Providers and Clients Perceive Interorganizational Networks?

Interorganizational networks are important structures for both service providers, who must navigate them as part of their organizational roles, and clients, who use them for the purposes of receiving benefits. This research develops and tests a conceptual model that explains some of the differences in the ways that these two groups perceive these networks. Drawing on surveys/interviews with 200 clients and 63 service providers of agricultural development training in Burkina Faso, this research demonstrates that clients perceive interorganizational networks differently than service providers. In particular, these results demonstrate that service providers perceive more organizations in the network, more competitive and collaborative ties among those organizations, and more competitive ties per organization than clients. From these results, we draw implications for social network, development communication, and organizational fields’ research

Aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of Anopheles gambiae s.l. from Burkina Faso

<br>Background: The operational impact of insecticide resistance on the effectiveness of long-lasting insecticide nets (LLINs) and indoor residual spraying (IRS) is poorly understood. One factor which may prolong the effectiveness of these tools in the field is the increase in insecticide susceptibility with mosquito age. In this study, LLINs and IRS were tested against young (three to five days) and old (17-19 days) pyrethroid resistant Anopheles gambiae s.l. from Burkina Faso.</br> <br>Methods: Blood-fed adult Anopheles gambiae s.l. were collected from south-west Burkina Faso and identified to species/form level. Cohorts of the F1 progeny of An. gambiae s.s. S-forms were exposed to deltamethrin (0.05%) at three to five or 17-19 days post-emergence and tested for the frequency of the resistance allele 1014F. Isofemale lines of the M, S- form of An. gambiae s.s. and Anopheles arabiensis were exposed in WHO cone tests to either a) LLINs deployed in households for two years or (b) bendiocarb sprayed walls.</br> <br>Results: Mortality rates in response to deltamethrin (0.05%) increased from levels indicative of strong resistance in three to five day old F1 mosquitoes, to near full susceptibility in the 17-19 day old cohort. On exposure to LLINs sampled from the field, the mortality rate in isofemale lines was higher in older mosquitoes than young (OR = 5.28, CI 95% = 2.81-9.92), although the mortality estimates were affected by the LLIN tested. In general, the LLINs sampled from the field performed poorly in WHO cone bioassays using either laboratory susceptible or field caught mosquito populations. Finally, there was a clear relationship between mortality and age on exposure to bendiocarb-sprayed walls, with older mosquitoes again proving more susceptible (OR = 3.39, CI 95% = 2.35-4.90).</br> <br>Conclusions: Age is a key factor determining the susceptibility of mosquitoes to insecticides, not only in laboratory studies, but in response to field-based vector control interventions. This has important implications for understanding the epidemiological impact of resistance. If mosquitoes old enough to transmit malaria are still being suppressed with available insecticides, is resistance potentially having less of an impact than often assumed? However, the poor performance of LLINs used in this study in Burkina Faso, is a cause for concern and requires urgent investigation.</br&gt

Field efficacy of a new mosaic long-lasting mosquito net (PermaNet® 3.0) against pyrethroid-resistant malaria vectors: a multi centre study in Western and Central Africa

<p>Abstract</p> <p>Background</p> <p>Due to the spread of pyrethroid-resistance in malaria vectors in Africa, new strategies and tools are urgently needed to better control malaria transmission. The aim of this study was to evaluate the performances of a new mosaic long-lasting insecticidal net (LLIN), i.e. PermaNet^®3.0, against wild pyrethroid-resistant <it>Anopheles gambiae s.l</it>. in West and Central Africa.</p> <p>Methods</p> <p>A multi centre experimental hut trial was conducted in Malanville (Benin), Vallée du Kou (Burkina Faso) and Pitoa (Cameroon) to investigate the exophily, blood feeding inhibition and mortality induced by PermaNet^®3.0 (i.e. a mosaic net containing piperonyl butoxide and deltamethrin on the roof) comparatively to the WHO recommended PermaNet^®2.0 (unwashed and washed 20-times) and a conventionally deltamethrin-treated net (CTN).</p> <p>Results</p> <p>The personal protection and insecticidal activity of PermaNet 3.0 and PermaNet^®2.0 were excellent (>80%) in the "pyrethroid-tolerant" area of Malanville. In the pyrethroid-resistance areas of Pitoa (metabolic resistance) and Vallée du Kou (presence of the L1014F <it>kdr </it>mutation), PermaNet^®3.0 showed equal or better performances than PermaNet^®2.0. It should be noted however that the deltamethrin content on PermaNet^®3.0 was up to twice higher than that of PermaNet^®2.0. Significant reduction of efficacy of both LLIN was noted after 20 washes although PermaNet^®3.0 still fulfilled the WHO requirement for LLIN.</p> <p>Conclusion</p> <p>The use of combination nets for malaria control offers promising prospects. However, further investigations are needed to demonstrate the benefits of using PermaNet^®3.0 for the control of pyrethroid resistant mosquito populations in Africa.</p