A survey of the antimicrobial resistance pattern of Escherichia coli O157:H7 strains obtained from stool samples collected from children with diarrhea attending General hospital Warri, General Hospital Agbor, Eku General Hospital and University of Benin teaching Hospital was carried out. All isolates were obtained using standard microbiological and biochemical procedures. Serological analysis to detect E. coli O157 strains was carried out using the dry spot E. coli O157 test kit. Antimicrobial susceptibility testing was carried out using disc diffusion method. A total of 46 Escherichia coli isolates were obtained from the 60 stool samples. All Escherichia coli isolated were 100% resistant to cefixime. The lowest level of resistance was observed in nitrofuratoin (15%). Serotypes O157 exhibited 100% resistance to ceftazidime, cefuroxime and cefixime. The ability of E. coli O157 strains to transfer antimicrobial resistance traits by conjugation was detected using Pseudomonas aeruginosa as recipient. High level of resistance transferred was observed. The ease of transfer exhibited by E. coli O157 strains amongst children in this study is an issue of concern. As such, an early identification and understanding of the epidemiology of this resistance will enable the development of preventive strategies which can curtail this emerging resistance, thereby facilitating a timely and appropriate public health response.

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The failure of antimicrobial agents in the treatment of some ailments has become a great concern to health care practitioners. This could be as a result of low quality drugs, sneaked into the market by those who fake them, thus, this study was carried out to evaluate the sensitivity of various brands of Amoxicillin and Ampicillin on clinical isolates of Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi. The test organisms were clinical bacterial isolates obtained from clinical samples from four hospitals/laboratories in Delta State, Nigeria. The antibiotics were subjected to two fold serial dilution method to determine the Minimum Inhibitory Concentration (MIC) from which the sensitivity of the isolates to the various brands of the antibiotics was determined. The result showed that the sensitivity of Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi to the various brands of Amoxicillin are 54, 62 and 68% respectively. The result also revealed that the sensitivity of Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi to Ampicillin are 64, 64 and 70% respectively. The result further indicates that a mean sensitivity of the isolates to Amoxicillin was 61%, while the mean sensitivity to Ampicillin was obtained as 66%. The study has therefore established the need for a routine evaluation of antibiotics and other pharmaceuticals in the Nigerian markets.

The antibacterial activity of the fresh and concentrated extracts of Alchornea cordifolia and Costus afer against five bacterial species was demonstrated in vitro. The diameter of the zones of inhibition ranged from 6.7±1.5mm to 39.±2.5mm for the fresh juices. The concentrated leaf and stem pith extracts had an inhibition range of 6.3±0.7mm to 22.0±2.5mm. The fresh stem pith juice of Alchornea cordifolia was the most potent plant part and K. varians (39.3±2.5mm) was the most susceptible isolate with a zone of inhibition, which compared well with the gentamycin control (39.3±0.6mm). Extracts from the concentrated leaves were more potent than the juice from the fresh leaves. A combination of the fresh juices did not result in higher zones of inhibition. The extracts obtained from the concentrated leaves and stem of C. afer did not inhibit any of the bacteria tested. The pattern of response exhibited by the bacteria to the extracts was shown by ANOVA to be significantly different. However, ANOVA showed no significant difference in the activity of the concentrated extracts from the leaves of lchornea cordifolia on K. varians (P>0.05). The stem pith and leaves of A. cordifolia can be exploited for use as antibacterial drugs against the bacteria tested since susceptibility to some of them compared well as to gentamycin. The traditional use of these plants for the treatment of diseases caused by the tested isolates was scientifically verified.

It is a common practice for clinicians to administer antimicrobial agents to patients suffering from bacterial infections without recourse to laboratory diagnosis which provides information on the antibiogram of the etiologic agents. This may result to the use of less efficacious drugs that might lead to long time hospitalization, death of patients and/or opportunity for bacterial species to develop resistant to some of these antimicrobial agents. This is the reason why, this study was carried out to determine the efficacy of five (5) brands of Ofloxacin; a typical floroquinolone antibiotic available in most pharmaceutical shops in Nigeria. Clinical isolates of Streptococcus pneumoniae and Staphylococcus aureus were exposed to twofold serial dilution of the antibiotic to determine the minimum inhibitory concentration (MIC). Result shows that the percentage strains of Streptococcus pneumoniae inhibited by the five brands of Ofloxacin investigated were 72, 74, 41, 68 and 76% respectively. Result also shows that the percentage strains of Staphylococcus aureus inhibited by the antimicrobial agent were 81, 85, 52, 79 and 85% respectively. Analysis of the result shows that the efficacy rate of Ofloxacin against Streptococcus pneumoniae and Staphylococcus aureus were 72 and 81% respectively. The result has shown that patients and health care providers can rely on this antimicrobial agent in the treatment of ailments associated with Streptococcus pneumoniae and Staphylococcus aureus in this locality provided the efficacy of the brand to be used is tested.

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