A STUDY OF THE SUSCEPTIBILITY OF METHICILLIN RESISTANT COAGULASE-NEGATIVE STAPHYLOCOCCI ISOLATED FROM FAECAL SAMPLES OF CHILDREN TO COMMONLY USED ANTISEPTIC AGENTS

Background: This study was carried out to provide information on the susceptibility of methicillin resistant coagulase-negative staphylococci (MRCoNS) faecal isolates to some commonly used antiseptic agents. Materials and Methods: For this purpose, 149 coagulase-negative staphylococci (CoNS) strains recovered from the faecal samples of children in Ile- Ife, a semi-urban settlement in Nigeria were screened against oxacillin by disc diffusion and agar screening methods. They were further screened against five antiseptic agents namely; benzalkonium chloride, cetrimide, chlorhexidine gluconate, gentian violet and acriflavine by the agar dilution method. Oxacillin resistant isolates were confirmed by screening for the mecA gene by the standard PCR method. Results: Oxacillin resistant isolates were 30.2%. While equal susceptibility was obtained for both MRCoNS and methicillin susceptible CoNS (MSCoNS) against gentian violet, reduced susceptibility to the order of one double dilution was obtained for MRCoNS against the remaining agents although the observed differences were not statistically significant (p > 0.05). Isolates generally showed highest susceptibility to chlorhexidine gluconate (MIC50=4mg/L; MIC90=32mg/L) while they were found to be least susceptible to gentian violet (MIC50=32mg/L; MIC90>32mg/L). S. hominis strains were the most susceptible to chlorhexidine gluconate (MIC5

ANTIBIOTIC RESISTANCE AND VIRULENCE PROPERTIES IN ESCHERICHIA COLI STRAINS FROM CASES OF URINARY TRACT INFECTIONS

This study determined E. coli resistance to commonly used antibiotics together with their virulence properties in Ile-Ife, Nigeria. A total of 137 E. coli isolates from cases of urinary tract infection were tested for their sensitivity to commonly used antibiotics and possession of virulence factors using standard methods. Their ability to transfer resistance was also determined. The isolates demonstrated a high and widespread resistance (51.1 % to 94.3 %) to all the antibiotics used except Nitrofurantoin (7.3 %). A total of 50 (36.5 %) of the isolates were resistant to 10 of the eleven antibiotics employed. Sixty three per cent (63 %) of the 107 trimethoprim resistant E. coli transferred their resistances while amoxicillin, gentamycin, augmentin, tetracycline and erythromycin were co-transferred with trimethoprim. Fifty one (37.2 %) of these multi-resistant isolates possessed one or more virulent factors. The study concluded that urinary tract infection due to E. coli in Ile-Ife may be difficult to treat empirically except with nitrofurantoin, due to high resistance to commonly used antibiotics. It is imperative that culture and susceptibility tests be carried out on infecting pathogen prior to treatment, in order to avoid treatment failure and reduce selective pressure that could result in the spread of uropathogenic E. coli in the environment

Rapid evolution of fluoroquinolone-resistant Escherichia coli in Nigeria is temporally associated with fluoroquinolone use

The genetic basis for antimicrobial resistance was studied in fecal Escherichia coli isolates in a Nigerian community in parallel with antimicrobial use. The results showed that fluoroquinolones, and not chloroquine as has been hypothesized elsewhere, appear to be the selective force for fluoroquinolone-resistant fecal E. coli in this setting. Jennie Crowe and Rebeccah Lijek are student co-authors. --author-supplied descriptio

Dissemination of the Transmissible Quinolone-Resistance Gene qnrS1 by IncX Plasmids in Nigeria

The plasmid-encoded quinolone resistance gene qnrS1 was recently found to be commonly associated with ciprofloxacin resistance in Nigeria. We mapped the qnrS1 gene from an Escherichia coli isolate obtained in Nigeria to a 43.5 Kb IncX2 plasmid. The plasmid, pEBG1, was sufficient to confer ciprofloxacin non-susceptibility, as well as tetracycline and trimethoprim resistance, on E. coli K-12. Deletion analysis confirmed that qnrS1 accounted for all the ciprofloxacin non-suceptibility conferred by pEBG1 and tetracycline and trimethoprim resistance could be attributed to tetAR and dfrA14 genes respectively. While it contained a complete IncX conjugation system, pEBG1 was not self-transmissible likely due to an IS3 element inserted between the pilX5 and pilX6 genes. The plasmid was however efficiently mobilizable. pEBG1 was most similar to another qnrS1-bearing IncX2 plasmid from Nigeria, but both plasmids acquired qnrS1 independently and differ in their content of other resistance genes. Screening qnrS1-positive isolates from other individuals in Nigeria revealed that they carried neither pEBG1 nor pNGX2-QnrS1 but that IncX plasmids were prevalent. This study demonstrates that the IncX backbone is a flexible platform that has contributed to qnrS1 dissemination in Nigeria

Regional Dissemination of a Trimethoprim-Resistance Gene Cassette via a Successful Transposable Element

Antimicrobial resistance is a growing international problem. We observed a 50% increase in the prevalence of trimethoprim resistance among fecal Escherichia coli from healthy Nigerian students between 1998 and 2005, a trend to increase that continued in 2009.A PCR-based screen revealed that 131 (43.1%) of isolates obtained in Nigeria in 2005 and 2009 carried integron-borne dfrA cassettes. In the case of 67 (51.1%) of these isolates, the cassette was a class 1-integron-borne dfrA7 gene, which has been reported at high prevalence from E. coli isolates from other parts of Africa. Complete sequencing of a 27 Kb dfrA7-bearing plasmid from one isolate located the dfrA7 gene within a Tn21-type transposon. The transposon also contained an IS26-derived bla/sul/str element, encoding resistance to β-lactams, sulphonamides and streptomycin, and mercury resistance genes. Although the plasmid backbone was only found in 12 (5.8%) of trimethoprim-resistant isolates, dfrA7 and other transposon-borne genes were detected in 14 (16.3%) and 32 (26.3%) of trimethoprim resistant isolates collected in Nigeria in 2005 and 2009, respectively. Additionally, 37 (19.3%) of trimethoprim-resistant E. coli isolates collected between 2006 and 2008 from Ghana were positive for the dfrA7 and a transposon marker, but only 4 (2.1%) harbored the plasmid backbone.Our data point to transposition as a principal mechanism for disseminating dfrA7 among E. coli from Nigeria and Ghana. On-going intensive use of the affordable broad-spectrum antibacterials is likely to promote selective success of a highly prevalent transposable element in West Africa

Socioeconomic and behavioral factors leading to acquired bacterial resistance to antibiotics in developing countries.

In developing countries, acquired bacterial resistance to antimicrobial agents is common in isolates from healthy persons and from persons with community-acquired infections. Complex socioeconomic and behavioral factors associated with antibiotic resistance, particularly regarding diarrheal and respiratory pathogens, in developing tropical countries, include misuse of antibiotics by health professionals, unskilled practitioners, and laypersons; poor drug quality; unhygienic conditions accounting for spread of resistant bacteria; and inadequate surveillance

The use of plants in the traditional management of diabetes in Nigeria: Pharmacological and toxicological considerations

Ethnopharmacological relevance: The prevalence of diabetes is on a steady increase worldwide and it is now identified as one of the main threats to human health in the 21st century. In Nigeria, the use of herbal medicine alone or alongside prescription drugs for its management is quite common. We hereby carry out a review of medicinal plants traditionally used for diabetes management in Nigeria. Based on the available evidence on the species׳ pharmacology and safety, we highlight ways in which their therapeutic potential can be properly harnessed for possible integration into the country׳s healthcare system. Materials and methods: Ethnobotanical information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed and Scopus up to 2013 for publications on medicinal plants used in diabetes management, in which the place of use and/or sample collection was identified as Nigeria. ‘Diabetes’ and ‘Nigeria’ were used as keywords for the primary searches; and then ‘Plant name – accepted or synonyms’, ‘Constituents’, ‘Drug interaction’ and/or ‘Toxicity’ for the secondary searches. Results: The hypoglycemic effect of over a hundred out of the 115 plants reviewed in this paper is backed by preclinical experimental evidence, either in vivo or in vitro. One-third of the plants have been studied for their mechanism of action, while isolation of the bioactive constituent(s) has been accomplished for twenty three plants. Some plants showed specific organ toxicity, mostly nephrotoxic or hepatotoxic, with direct effects on the levels of some liver function enzymes. Twenty eight plants have been identified as in vitro modulators of P-glycoprotein and/or one or more of the cytochrome P450 enzymes, while eleven plants altered the levels of phase 2 metabolic enzymes, chiefly glutathione, with the potential to alter the pharmacokinetics of co-administered drugs. Conclusion: This review, therefore, provides a useful resource to enable a thorough assessment of the profile of plants used in diabetes management so as to ensure a more rational use. By anticipating potential toxicities or possible herb–drug interactions, significant risks which would otherwise represent a burden on the country׳s healthcare system can be avoided

Species Distribution and Antibiotic Resistance in Coagulase-negative Staphylococci Colonizing the Gastrointestinal Tract of Children in Ile-Ife, Nigeria

Purpose: The antimicrobial susceptibility of 149 coagulase-negative staphylococci (CoNS) isolates from faecal samples of children in Ile-Ife, Nigeria, was evaluated in order to determine their contribution to antimicrobial resistance in the community. Methods: The isolates were identified to the species level by conventional methods, and their susceptibility to 20 antibiotics was tested by disk diffusion and to vancomycin by agar dilution. Results: The species distribution was as follows: Staphylococcus epidermidis 45 (30.2 %), S. haemolyticus, 26 (17.5 %); S. capitis, 24 (16.1 %); S. xylosus, 11 (7.4 %); S. saprophyticus, 8 (5.4 %); S. warneri, 8 (5.4 %); S. hominis, 6 (4.0 %); S. schleiferi, 5 (3.3 %); S. lugdunensis, 3 (2.0 %) and S. capitis sub ureolyticus, 3 (2.0 %) and isolates from other CoNS species 10 (6.7 %). Resistance to the β-lactam antibiotics was in excess of 50 % of the isolates tested whilst there was significant incidence of resistance to cotrimoxazole, chloramphenicol, tetracycline, erythromycin, fusidic acid and norfloxacin. The highest percentage of oxacillin resistance was found among S. haemolyticus (46.2%) while the lowest was in S. capitis (8.3%). Reduced susceptibility (MIC ≥ 4mg/L) to vancomycin was shown by both oxacillin-resistant and susceptible CoNS species. Conclusion: The gastrointestinal tracts of children could serve as a reservoir for antibiotic-resistant CoNS, some of which had reduced susceptibility to vancomycin