Emergence of Third Generation Cephalosporin Resistance and Typing by Randomly Amplified Polymorphic DNA (RAPD) among Clinical Salmonella Isolates from Lagos, Nigeria.

Aims: To investigate emergence of cephalosporin resistance and clonal relatedness among clinical Salmonella isolates recovered from patients in Lagos, Nigeria. Study Design: It is an investigative study. A total of 300 patients who presented with various types of medical conditions at prominent referral public hospitals were recruited. Place and Duration of Study: Department of Microbiology, Lagos State University, Ojo, Lagos and Nigerian Institute of Medical Research, Yaba, Lagos, Nigeria from July 2011 to May 2012. Methodology: Salmonella identification was done using standard methods. The isolates were subjected to antimicrobial susceptibility by disk diffusion method. The isolates were further screened for plasmid DNA and blaCTX-M carriage on plasmid using alkaline lysis and PCR methods. Clonal relatedness of the isolates was assessed by RAPD PCR using genomic DNA as template for three RAPD primers (784, 1254 and OPA4). The resulting RAPD types were determined by visualization and discrimination index was measured using a discriminating index calculator. Results: Sixty three Salmonella isolates were recovered made up of five serovars. In all 49% of the isolates were resistant to cefuroxime, 46% to cefoxitin, 37% to cefriazone and 35% to ceftazidine. Interestingly 28(87.5%) of the 32 ESBL producing Salmonella isolates possessed at least one or more plasmids from five distinct sizes recorded 2.5; 4; 9; 15;23.5kb. Four distinct RAPD profiles were exhibited by the test strains. The total discriminatory power among the isolates was 0.77 (77%). Conclusion: Third generation cephalosporin resistance involving blaCTX-M has emerged among clinical Salmonella isolates in Lagos. RAPD elicits potential as a cost-effective and time saving tool for local discrimination of clinical Salmonella isolates for epidemiological purposes.

Enhanced Antimalarial Effects of Chloroquine by Aqueous Vernonia Amygdalina Leaf Extract in Mice Infected with Chloroquine Resistant and Sensitive Plasmodium berghei strains

Background: The emergence and spread of Plasmodium falciparum with resistance to chloroquine (CQ); the safest and cheapest antimalarial drug coupled with the increasing cost of alternative drugs especially in developing countries have necessitated the need to optimize antimalarial actions of plant extracts and restore chloroquine efficacy. Objective: The present study determines the ability of Vernonia amygdalina leaf extract to enhance the prophylactic and therapeutic efficacy of chloroquine against Plasmo- dium berghei malaria in mice. Methods: Chloroquine sensitive (P. bergheiS) and resistant (P.bergheiR) ANKA clones of Plasmodium berghei maintained by serial passage in mice were used to develop respective experimental rodent malaria models based on intraperitoneal injection of 106 parasitize erythrocyte suspension in PBS (pH 7.2) and subsequent development of parasitaemia. These models were then used to investigate the prophylactic enhancement of chloroquine (CQ) at 5 mg/kg via combination with selected doses (31.25; 62.5; 125mg/kbw) of Vernonia amygdalina leaf extracts using a 4-day suppression test. Effect of these combinations on the therapeutic efficacy of CQ at 30mg/kg over 3 days were evaluated. Treatment outcomes including parasite clearance (PCT) and rescrudescent time (RT) were compared with CQchlorpheniramine com-bination. The acute toxicity of the extract-CQ combinations was also determined enzymatically. Results: Prophylatically; chloroquine (5mg/kg) in combination with vernonia extracts achieved a dose-dependent (57.2 - 72.7) suppression of parasitaemia due to CQ sensitive and resistant P berghei strains in the experimental animals. Therapeutically; chloroquine (30mg/kg for 3 days) combined with vernonia to dose-dependently shorten the parasite clearance times (2.6 - 4.4 vs. 4.8 days; P 0.05 for CQ-V62.5/125 combination); prolong the recrudescent times (8.9 - 18.9 vs. 7.2 days; P 0.05) and improve day 14 cure rate (66.7 - 100 vs. 58.3) in the treated P. bergheiS infected mice compared to CQ monotherapy. Whereas CQ monotherapy failed; resolution of parasitaemia due to the CQ resistant parasite with day 14 cure rates of 25 - 100were also observed with these combinations. In therapeutic terms; the potencies of CQ-V125 combination were comparable to those of CQ-chlorpheniramine (0.25mg/kg; 12hourly; 7 days) in the infected animals. Toxicity testing indicates that these combinations elicited mild to - moderate increases in the liver enzymes measured when adminis- tered orally to mice for 7 days. Conclusion: This study indicates that Vernonia amygdalina leaf extract dose - dependently restore the efficacy of CQ against CQ resistance P. berghei malaria in mice

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 1 yr; 1 - 5 yr and 5 yr and 50 age and sex-matched non-diabetic subjects attending General Hospitals; Lagos; Nigeria. Blood pressures (SBP et 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) among the diabetic groups; suggesting a linear relationship with the duration of diabetes in these patients. 26 of non-diabetics had microalbuminuria of no significant disparity (P 0.05) when compared to diabetics of 1 yr-old duration. Multiple regression analyses indicate significant association (P 0.05) between SBP; DBP; TC; LDL-C and microalbuminuria in diabetic 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

Patterns and properties of haemagglutinins expressed by Shigella serogroups in Lagos, Nigeria.

Forty-five strains of Shigella were screened for haemagglutinin production and broad-spectrum haemagglutination reaction. Mannose-sensitive haemagglutinin (MSHA) was found in 22 strains [Shigella flexneri (7), S. dysenteriae (7), S. sonnei (3), and S. boydii (5)]. Eighteen strains harboured mannose-resistant haemagglutinin (MRHA), and 8 strains were observed to be non-haemagglutinating to guinea pig erythrocyte. With the exception of human erythrocytes (O, A, B, and AB), the observed MSHA and MRHA also agglutinated the erythrocytes of rabbit, sheep, rat, chicken, and horse, suggesting a broad-spectrum haemagglutinating property. Haemagglutinins of S. flexneri and S. dysenteriae elicited a relatively stronger haemagglutinating activity with agglutinability to chicken and rabbit erythrocytes enhanced by trypsinization. Haemagglutination reaction with guinea pig erythrocyte was generally inhibited by sialic acid, while simple sugars, such as D-glucose, D-galactose, N-acetylgalactosamine, N-acetylglucosamine, and D-rhamnose, elicited no inhibitory effect. The results of the study revealed broad-spectrum haemagglutinin expression by circulating Shigella strains in Nigeria.

Shigellocidal properties of three Nigerian medicinal plants: Ocimum gratissimum, Terminalia avicennoides, and Momordica balsamina.

The prevalence of multidrug-resistant shigellae is an important concern in the treatment of shigellosis in many developing countries, and other therapies, including herbal agents, may provide an important alternative to antimicrobial agents. In this study, three Nigerian medicinal plants: Ocimum gratissimum, Terminalia avicennoides, and Momordica balsamina were investigated for their activities against multidrug-resistant Shigella species isolated from patients with bacilliary dysentery in Lagos. Decoctions of O. gratissimum and concoctions of O. gratissimum and T. avicennoides at crude concentration of 3,000 micrograms/mL markedly inhibited the growth of all isolates tested. Zones of inhibition indicating susceptibilities of the organisms varied from 18.3 to 21.5 mm for Shigella dysenteriae, 15.3 to 16.3 mm for S. flexneri, 18.8 to 19.3 mm for S. sonnei, and 16.5 mm for S. boydii. Except S. flexneri, minimum inhibitory concentration and minimum bactericidal concentration revealed a higher shigellocidal property of O. gratissimum/T. avicennoides concoction than other extracts in S. dysenteriae (300-515.6 vs 337.5-1,312.5 micrograms/mL), S. sonnei (309.4-543.8 vs 403.1-1,312.5 micrograms/mL), and S. boydii (243.8-337.5 vs 253-1,312.5 micrograms/mL). O. gratissimum showed a greater shigellocidal effect against the S. flexneri isolates, while extracts of M. balsamina possessed low shigellocidal potential. The results suggest that aqueous extracts of O. gratissimum and T. avicennoides as decoctions and concoctions could be useful in the treatment of shigellosis and should be clinically evaluated specially in Nigerian region.

Epidemiology of shigellosis in Lagos, Nigeria: trends in antimicrobial resistance.

Antimicrobial susceptibility of Shigella spp. and Escherichia coli, isolated from diarrhoeal patients in Lagos, was studied from March 1999 to February 2000. Four hundred fifty-nine isolates were identified as shigellae (62) and E. coli (397). Shigella flexneri, S. dysenteriae, S. boydii, and S. sonnei accounted, respectively, for 51.6%, 17.7%, 17.7%, and 13% of the total number of shigellae isolated. Eleven cases of shigellosis occurred in the age group of 0-9 years, 22 cases in the age group of 10-19 years, and 29 cases in the age group of > or = 20 years. Of the 397 E. coli isolates, 11 were enteropathogenic E. coli (EPEC), and 7 of these strains were isolated with shigellae from stools of patients aged 0-9 year(s) (71.4%) and 10-19 years (28.6%). Over 70% of the Shigella isolates were resistant to two or more drugs, including ampicillin and tetracycline. Twenty-one distinct multidrug resistance patterns were observed in these isolates. During 1990-2000, resistance to ampicillin increased from 70% to 90%, co-trimoxazole from 77% to 85%, chloramphenicol from 71% to 77%, streptomycin from 71% to 79%, and nalidixic acid from 0% to 11.3%. Resistance to tetracycline decreased from 89% to 79% but with MIC50 and MIC90 values outside the susceptible range. While resistance to ciprofloxacin and ofloxacin remained nil with MIC50 and MIC90 values of 0.008 and 0.0016 microgram/mL respectively. The results of this study revealed the endemicity of shigellosis with S. flexneri as the predominant serogroup in Lagos. Children and young adults were at a higher risk of severe shigellosis. The results also suggest that ampicillin, tetracycline, co-trimoxazole, and streptomycin should not be used as the first-line drugs in the treatment of shigellosis. Nalidixic acid should still be selectively used for treatment, while ciprofloxacin and ofloxacin can be ideal alternatives.