Microbiological assessment of indoor air of a teaching hospital in Nigeria.

OBJECTIVE: To investigate the quality of indoor air of different wards and units of Olabisi Onabanjo University Teaching Hospital, Sagamu, to ascertain their contribution to infection rate in the hospital. METHODS: The microbial quality of indoor air of nine wards/units of Olabisi Onabanjo University Teaching Hospital, Sagamu, Nigeria was conducted. Sedimentation technique using open Petri-dishes containing different culture media was employed and samplings were done twice daily, one in the morning shortly after cleaning and before influx of people/patients into the wards/units and the other in the evening when a lot of activities would have taken place in these wards. Isolates were identified according to standard methods. RESULTS: Results showed that there was a statistically significant difference (χ(2) = 6.016 7) in the bacteria population of the different sampling time whereas it was not so for fungi population (χ(2) = 0.285 7). Male medical ward (MMW) and male surgical general (MSG) recorded the highest bacterial and fungal growth while the operating theatre (OT) was almost free of microbial burden. The bacteria isolates were Staphylococcus aureus, Klebsiella sp., Bacillus cereus, Bacillus subtilis, Streptococcus pyogenes and Serratia marscences while the fungi isolates included Aspergillus flavus, Penicillium sp., Fusarium sp., Candida albicans and Alternaria sp. Staphylococcus aureus was the predominantly isolated bacterium while Penicillium sp. was the most isolated fungus. CONCLUSIONS: Though most of the microbial isolates were potential and or opportunistic pathogens, there was no correlation between the isolates in this study and the surveillance report of nosocomial infection during the period of study, hence the contribution of the indoor air cannot be established. From the reduction noticed in the morning samples, stringent measures such as proper disinfection and regular cleaning, restriction of patient relatives' movement in and out of the wards/units need to be enforced so as to improve the quality of indoor air of our hospital wards/units.

Foliar blight of Roselle and its effect on yield in tropical forest region of southwestern Nigeria.

The etiology of foliar blight of roselle and its effect on yield in the tropical forest of southwestern Nigeria was investigated. More than 40% of leaves of roselle plants in fields under continuous cultivation (endemic plots) were blighted by Phyllosticta hibiscini. However, no infection was found on roselle plants in fields never previously planted with roselle. Over 20% leaf yield loss and over 34% edible leaf loss were due to leaf blight. The mean marketable and biological yield loss of calyces in 1999 and 2000 were 35% and 38% respectively, while seed yield loss was 30% and 32%.

Screening of cassava and yam cultivars for resistance to anthracnose using toxic metabolites of colletotrichum species.

Collectotrichum gloeosporioides f. sp. manihotis and C. gloeosporioides, causal agents of cassava (Manihot spp.) and yam (Dioscorea spp.) anthracnose diseases, respectively, produce toxic metabolites in culture that fluoresce at 254 nm and 366 nm, producing bands with Rf of 0.65 and 7.0, respectively. Symptoms induced on yam and cassava by the extracted metabolites were similar to those induced by the pathogens. Twenty-four clones of tropical D. rotundata (TDr), D. alata (TDa), D. esculenta (TDe), and D. cavenensis (TDc) were screened by applying toxic metabolites of C. gloeosporioides to their leaves and stems. Only TDr131, TDe179 and TDc750 were resistant. Other clones were susceptible to varying degrees. Nineteen of the 45 clones of M. esculenta were resistant to varying degrees of toxic metabolites of C. gloeosporioides f. sp. manihotis. Results from in vitro screening of' cassava and yam clones using toxic metabolites compared favourably with field screening based on natural epidemics. Using toxic metabolites appears to be a more effective technique for screening for disease resistance than conventional inoculation with plant pathogens.

Foliar blight in Centrosema pubescens (Benth.) in southwestern Nigeria.

The etiology and epidemiology of leaf blight of centro (Centrosema pubescens Benth.) was investigated at Ibadan, southwestern Nigeria, in the lowland humid tropics. Rhizoctonia solani was associated with the leaf blight of centro. The pathogen was harboured by Rottboellia cochinchiensis, a weed growing within and outside the centro plot. A high inoculum population of 4.0 +/- 0.3 x 106 colony forming units/g soil was estimated in the soil. The seed of centro were free of R. solani. Field infection of the disease occurs during the peak of the rainy season beginning in patches which later spread, causing extensive defoliation of the sward.