Comparative biochemical and molecular evaluation of swarming of Proteus and effects of anti-swarm agents

In addition to inadequate understanding of swarming motility and virulence of Proteus, there is paucity of information on the relative effectiveness of the various anti-swarm agents. The anti-swarming effects of urea, sodium dodecylsulphate (SDS) and trihydroxymethylglycine (Tris) on 40 clinical isolates of Proteus Spp. were comparatively investigated and plasmids associated with swarming were characterized. The three substances elicited a comparable concentration-dependent anti-swarming property at 0.25 – 1.25% on nutrient agar. Anti-swarm agents displayed heterogeneity in their ability to cause significant decreases in the expression of virulence factors. Swarm motility was further found to be strongly associated with the expression of virulence factors in these strains. Of the Proteus strains tested, 32 were found to harbour 1 – 4 plasmids of size ranging from 6.0 – 33.5 kb. Plasmid curing resulted in loss of swarming in 65.6% of these strains. In order to reduce the risk of infection with virulent Proteus strains, the laboratory use of urea and SDS is suggested. Key Words: Proteus, swarming, urea, SDS, Tris. African Journal of Biotechnology Vol.3(1) 2004: 99-10

Incidence and evaluation of risk factors of microalbuminuria among diabetics and non-diabetics in Lagos, Nigeria

Contrary to African diabetic situation, clinical studies in developed countries have recognized microalbuminuria as a risk factor of renal dysfunction and pathogenic agent for deterioration of diabetes mellitus in diabetic and non-diabetic populations. This clinical understanding has enabled optimization of clinical practices that improve prognosis of diabetic management and reduce susceptibility to renal disease. This present study has investigated the incidence and risks of microalbuminuria in 115 diabetic patients aged 5 – 65 years with illness duration of 5 yr and 50 age and sex-matched non-diabetic subjects attending General Hospitals, Lagos, Nigeria. Blood pressures (SBP & DBP) and plasma levels of total cholesterol (TC), triglycerides (TAG), low-density lipoprotein (LDL-C) and high-density lipoprotein (HDL-C) as well as body mass index (BMI) were determined to establish associations with microalbuminuria. The incidence of microalbuminuria was found to be 22.2%, 31.6% and 59.1% (P 0.05) when compared to diabetics of 5 yr. While all the atherogenic parameters except LDL-C associate strongly (P < 0.05) with microalbuminuria in diabetics of 1 – 5 yr. The lipid atherogenic components minus TAG were found to relate strongly with microalbuminuria in diabetics of < 1yr duration. Elevated BMI strongly predicts the risk of microalbuminuria in the non-diabetics examined. Keywords: microalbuminuria, diabetics, non-diabetics, atherogenic parameters, Lagos Nigerian Journal of Health and Biomedical Sciences Vol. 5(1) 2006: 81-8

A rodent malarial model of Plasmodium berghei for the development of pyrimethamine and sulphadoxine-pyrimethamine resistant malaria in mice

This study investigated the development of pyrimethamine (pyr) and sulphadoxine-pyrimethamine (S/P) resistance in Plasmodium berghei, a rodent parasite in mice using a serial technique (3.50 – 10mg/kg pyrimethamine) and a single treatment course approach with 125/6.25mg/kg S/P. The stability of resistance phenotypes, parasite pathogenic disposition and host leukocyte response were also investigated. The sequential and continuous increased-dose exposure of drug naïve parasites to pyrimethamine resulted in the development of two distinct resistant clone generations: PB10-1 and PB10-2 (3.5mg/kg pyr bypass clone) in 66.7% and 41.7% (P 0.05) on days 13 – 18 post inoculation that was significantly (P 10 and 3 – 5 weekly passages respectively in undrugged mice. The two clones further exhibited virulence disparity in their ability to cause significant (P < 0.05) increases in ALT (70.4 – 80.2 ± 3.4 – 3.8 vs. 31.8 ± 1.1 U/L) and AST (78.7 – 84.1 ± 3.1 – 3.7 vs. 38.6 ± 2.4 U/L) and reduction in total peripheral leukocyte count (3.2 – 4. 6 x 103 vs. 1.8 x 104 /mm3) when compared to the control. Resistance to S/P by 10%, 50% and 70% in sensitive, PB10-2 and PB10-1 clones was also observed, suggesting a non-requirement of pyr resistance for the development but necessity for the intensification of S/P resistance. Keywords: Plasmodium berghei, Malaria, Sulphadoxine-pyrimethamine resistance Nigerian Journal of Health and Biomedical Sciences Vol. 5 (2) 2006: 30-3

Preliminary investigation of the antibacterial activity of Acalypha hispida leaf extracts against local bacterial isolates from skin infections

Acalypha hispida leaf extracts are used locally for the treatment of skin infections. We sought to obtain laboratory-based evidence for this practice by evaluating the antibacterial activity of this extract against local isolates of bacteria obtained from skin lesions and wounds. Aqueous and ethanolic extracts were evaluated using the agar well diffusion method against Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes, Escherichia coli, Klebsiella species, and Salmonella typhimurium. S. aureus (ATCC standard and local) and Ps. Aeruginosa isolates were sensitive to all the extracts but one. E. coli (ATCC standard and local), S. enterica serovar typhimurium and Klebsiella species were only sensitive to the soxhlet leaf extracts while S. pyogenes was sensitive to only the ethanolic soxhlet extract. Though there was no statistically significant difference in the antibacterial activity of the 5-days and 14-days neat extracts obtained by soaking in water (p = 0.13) and ethanol (p = 0.08), their antibacterial activity decreased with longer soaking periods. Likewise, there was no significant difference in the antibacterial activity of the neat water and ethanolic soxhlet extracts (p = 0.48). The results show that A. hispida leaf extracts showed some in vitro antibacterial activity and that aqueous extraction using heat would be the preferred option. Keywords: Acalypha hispida, antibacterial, skin infections, aqueous extract, ethanolic extract Nigerian Journal of Health and Biomedical Sciences Vol. 5 (2) 2006: 12-1

Persistence of chloroquine-resistant haplotypes of Plasmodium falciparum in children with uncomplicated Malaria in Lagos, Nigeria, four years after change of chloroquine as first-line antimalarial medicine.

BACKGROUND: In Nigeria, despite the change in National malaria drug policy to artemisinin combination therapy (ACT) in 2005 due to widespread chloroquine resistance, chloroquine (CQ) is still widely used in the treatment of malaria because it is cheap, affordable and accessible. The use of ACT for the management of uncomplicated malaria is currently being promoted. The employment of genetic markers to track circulating chloroquine-resistant parasites are useful in elucidating likely poor efficacy of chloroquine, especially in settings where it is not recommended for the treatment of uncomplicated falciparum malaria. This study determined the prevalence of pfcrt haplotypes and point mutations in pfmdr1 genes four years after the change in antimalarial treatment policy from CQ to the ACTs in Lagos, a commercial city in South-West, Nigeria. METHODS: This was a cross sectional study on uncomplicated malaria in children less than 12 years that presented with fever and other symptoms suggestive of malaria. Parasite DNA was extracted from 119 patients out of 251 children who were positive for Plasmodium falciparum by microscopy and amplified. The occurrence of haplotypes was investigated in pfcrt gene using probe-based qPCR and single nucleotide polymorphisms in pfmdr1 gene using nested PCR. RESULTS: One hundred and nine (109) of the 119 children with P falciparum infection (91.6%) harbourd parasites with the mutant pfcrt haplotype (CVIET). Out of this, 4.2% comprised a mixture of genotypes encoding CVMNK and CVIET, while 4.2% had the wild type (CVMNK). Furthermore, the frequency of point mutations in pfmdr1 was 62.2% and 69.0% for codons Y86 and F184 respectively. There were no mutations at codons 1034, 1042 and 1246 of the Pfmdr1 genes. CONCLUSION: The high frequency of the CQ-resistant haplotypes (CVIET) and mutations in Pfmdr1 associated with CQ resistance in P. falciparum among these children suggest that CQ-resistant parasites are still in circulation. Continuous use of chloroquine may continue to increase the level of mutations in pfcrt and pfmdr1genes. There is need to strengthen current case management efforts at promoting ACT use as well as urgently restricting access to chloroquine by the National drug regulatory agency, National Agency for Food Drug Administration and Control (NAFDAC). VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2069472010142303