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http://hdl.handle.net/1956/2585
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| Tittel: | Antibiotic resistance in oral microbiota : a study on prevalence, molecular analysis, and possible contributing factors in Yemen and Norway |
| Forfattere: | Al-Haroni, Mohammed |
| Dato: | 2-Nov-2007 |
| Forlag: | The University of Bergen |
| Sammendrag: | Worldwide antibiotic resistance among oral microbiota is an increasing problem and
information regarding such resistance is completely lacking for Yemen and very limited
data is available for Norway. The aims of the current thesis were to (1) disclose
the prevalence of ampicillin and metronidazole resistance among selected subgingival
microbial species obtained from individuals in Yemen and Norway (paper 1), (2)
determine the susceptibility pattern of Fusobacterium nucleatum isolated from
Yemen and characterize the aminopenicillins-resistance determinant of F. nucleatum
(paper 2), and (3) assess if antimicrobial prescription practices by dentists in Yemen
and Norway could possibly contribute to the current prevalence and the emergence of
bacterial resistance in these geographically separate locations (papers 3 and 4).
Materials: Thirty-four and 21 subgingival plaque samples from Yemen and Norway,
respectively, were cultivated on fastidious anaerobic blood agar containing 2 μg/mL
of either ampicillin or metronidazole. The bacterial growth from each plate was then
screened using DNA-DNA checkerboard hybridization technique for the presence of
ampicillin and metronidazole resistance among 18 selected subgingival species
(paper 1). Ampicillin-resistant F. nucleatum strains were isolated from Yemen by
cultivating subgingival plaque samples on crystal violet erythromycin (CVE) plates
supplemented with or without 2 μg/mL ampicillin. The molecular basis of ampicillin
resistance among F. nucleatum strains was studied using two-dimensional gel electrophoresis
and mass spectrometry (paper 2).The antimicrobials prescription knowledge
of Yemeni dentists was investigated by distributing a structured questionnaire to all
working dentists in the three major governorates in Yemen. The questionnaire aimed
at investigating the therapeutic and prophylactic use of antimicrobials with relevant
clinical and non-clinical parameters (paper 3). The Norwegian dentists’ antimicrobial
prescription practices were revealed by analyzing aggregated data obtained from the
Norwegian Prescription Database (NorPD) on the basis of their total prescriptions of
11 antibiotics issued in 2004 and 2005. Consumptions of these antibiotics in dental
practice were measured using the WHO measurement unit, the Defined Daily Dose (DDD) (paper 4). Results: A statistically significant higher resistance to metronidazole
and ampicillin among nine and seven species (P <0.05), respectively, was found
in Yemeni isolates compared with Norwegian ones. The molecular characterization
of ampicillin-resistant F. nucleatum isolates showed that ampicillin-resistant F.
nucleatum isolates harboured a class D β-lactamase enzyme. In addition, increased
synthesis of two proteins, enolase and ABC transporter ATP-binding proteins, was
associated with β-lactamase enzyme production. A sound knowledge of antimicrobials
prescription among Yemeni dentists was lacking with a trend of overuse. NorPD
data showed antimicrobial prescribing trend in favour of narrow-spectrum penicillins
among Norwegian dentists. Conclusions: The findings indicate that high prevalence
of resistance among oral bacteria in Yemen maybe a potential threat in the management
of dental infections in the region. Antimicrobial overuse by dentists in Yemen
could exacerbate the existing dilemma of antimicrobial resistance of oral bacteria. In
contrast, the low prevalence of resistance among subgingival species in Norway is
most probably a result of the judicious use of antimicrobials, that is, more restrictive
prescribing practices in the country. The presence of class D β-lactamase among ampicillin-
resistant F. nucleatum strains increases their virulence and cost of treatments
as these enzymes might present resistance to several classes of β-lactam antibiotics.
Recommendations: Halting resistance development and saving effectiveness of antimicrobials
need strict, practical, and feasible approaches. There is an urgent need to
formulate an action plan to counter the revealed situation of antimicrobial resistance
in Yemen. A proposed strategy to be adopted in the country for the control of antimicrobial
resistance should be based on the prevention of communicable diseases and
infection control to reduce the need for antimicrobial agents. An antimicrobial resistance
surveillance system and a multidisciplinary committee that monitors antimicrobial
use in the country should form integral parts of a structured approach to reduce
antimicrobial resistance by improving antimicrobial prescribing. Finally, such an effective
strategy requires close cooperation and consultation between Yemen and
other involved parties, both at national and international levels. |
| URI: | http://hdl.handle.net/1956/2585 |
| ISBN: | 978-82-308-0432-2 (print version) |
| Vises i samlingene: | Department of Oral Sciences
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