Antibiotic use or misuse?

Isolation and Typing of Streptococcus mutans and Streptococcus sobrinus from Caries-active Subjects

Background

Streptococcus mutans and Streptococcus sobrinus are main etiological agents of dental caries.

Aim

The aim of the study was to isolate, identify, characterize, and determine the minimum inhibitory concentration (MIC) of S. mutans and S. sobrinus from caries-active subjects.

Materials and Methods

Sixty-five plaque samples were collected from caries-active subjects aged between 35 and 44 years, processed and cultured on mitis salivarius bacitracin agar. All the bacterial isolates were subjected to morphotyping and the suspected colonies were identified by 16S rDNA sequencing. The S. mutans and S. sobrinus strains were characterized by biotyping and phylogenetic analysis. The MIC of ampicillin and erythromycin was determined by microtiter plate method.

Results

Of the study population, 41 isolates displayed typical colony morphologies of S. mutans and S. sobrinus. The 16S rDNA sequencing results revealed that 36 isolates were S. mutans and 5 isolates were S. sobrinus. The biotyping of these isolates demonstrated three biotypes, namely, biotype I (n = 35), biotype III (n = 1), and biotype IV (n = 2). However, 3 isolates exhibited variant biotypes. The phylogenetic analysis revealed that the clinical strains of S. mutans and S. sobrinus clustered independently along with respective reference strains. The average MIC of ampicillin and erythromycin against S. mutans and S. sobrinus was 0.047 μg/ml and 0.39 μg/ml, respectively.

Conclusion

The 16S rDNA sequencing was an impeccable method for S. mutans and S. sobrinus identification when compared with morphotyping and biotyping methods. The study also suggested that nonspecific bacteria might be involved in caries formation.

Control of fluoroquinolone resistance through successful regulation, Australia

Fluoroquinolone antimicrobial drugs are highly bioavailable, broad-spectrum agents with activity against gram-negative pathogens, especially those resistant to other classes of antimicrobial drugs. Australia has restricted the use of quinolones in humans through its national pharmaceutical subsidy scheme; and, through regulation, has not permitted the use of quinolones in food-producing animals. As a consequence, resistance to fluoroquinolones in the community has been slow to emerge and has remained at low levels in key pathogens, such as Escherichia coli. In contrast to policies in most other countries, this policy has successfully preserved the utility of this class of antimicrobial drugs for treatment of most infections.

Antibiotic prophylaxis in oral health care: administration strategies of general dental practitioners

OBJECTIVE

To examine the strategies that general dental practitioners (GDPs) use to administer antibiotic prophylaxis and to study the agreement between the administration strategies of GDPs and local recommendations.

METHODS

Postal questionnaires in combination with telephone interviews were used. Two hundred GDPs in two Swedish counties, Skåne and Orebro, were asked to participate. The response rate was 51% (n = 101). The GDPs were presented with eight simulated cases of patients with different medical conditions for which antibiotic prophylaxis might be considered necessary when performing dental procedures (scaling, tooth removal, root canal treatment). The administration strategies of the GDPs were compared with local recommendations.

RESULTS

In general, the variation in the administration strategies of the GDPs was large. For two medical conditions, type 1 diabetes that was not well controlled and hip prosthesis, significantly more GDPs in Skåne than in Orebro administered antibiotic prophylaxis for tooth removal. Agreement between the administration strategies of the GDPs and local recommendations was low. Differences between the two counties were non-significant. Furthermore, within Orebro, GDPs who did not have formal access to local recommendations did not differ in their administration strategies from those who did. The choice of substance was seldom in agreement with the substance recommended, while the majority followed the recommended duration of treatment.

CONCLUSION

Although recommendations existed, their impact appeared to be limited. This is significant, since the implementation of recommendations is crucial in making clinical practice more effective and in promoting the health of patients.

What do physicians think about evidence-based antibiotic use in critical care? A survey of Australian intensivists and infectious disease practitioners

BACKGROUND

The analysis of factors that influence prescribing decisions is increasingly important. Antibiotic use is often based on limited evidence and lack of information about clinical decision-making processes is an important obstacle to improving antibiotic utilization.

AIMS

To compare the attitudes of intensive care unit practitioners (ICUP) and infectious disease practitioners (IDP) to antibiotic use and to the evidence-based information support.

METHOD

A postal survey conducted between March and July 2000 of ICUP and IDP representing all States and Territories in Australia.

RESULTS

One hundred and fifty-three of 224 clinicians returned the questionnaire (68.3% response rate). In choosing an antibiotic, IDP placed significantly more weight than ICUP on the in vitro susceptibility of the pathogen (P = 0.001), antibiotic cost (P = 0.05) and possible development of antibiotic resistance (P = 0.007). More than 95% of both groups believed that unit-specific antibiotic susceptibility of endemic pathogens was an essential factor in rational prescribing, but only 68.5% of IDP and 38.7% of ICUP use microbiology laboratory databases. When in doubt about appropriate antibiotic use, 63.8% of ICUP seek and 76.3% usually follow the advice of IDP. Both groups agree that published antibiotic guidelines are useful, but IDP were more likely to consult them. ICUP were more likely to believe that guidelines are used to control clinicians rather than to improve quality of care (P = 0.001). A greater proportion of IDP (71.2%) than ICUP (52.5%) believed that antibiotic prescribing in their intensive care unit (ICU) was evidence based but most (91.8% and 86.9%, respectively) agreed that it should be.

CONCLUSIONS

Australian clinicians have positive views about evidence-based prescribing and antibiotic guidelines. However, there are clinically significant differences in prescribing behaviour between ICUP and IDP. These may be explained by different disease spectra managed by each group or different cultures, training and/or cognitive styles. Improvements in the understanding of physicians' information and decision support needs are required to strengthen evidence-based prescribing.

Antibiotic prescribing practices by South Australian general dental practitioners

The prescribing habits of a randomly selected approximately 10 per cent sample of South Australian general dental practitioners were obtained by postal questionnaire. Sixty-eight (61 per cent) usable replies were received and analysed. Generally, there was an appropriate level of knowledge of antibiotic prescription. However, there was a tendency toward over-prescription and a demonstrated lack of knowledge of the incidence of adverse reactions, development of multiresistant strains and prophylaxis against bacterial endocarditis. All of these areas are real challenges to the profession, whether in an overall global community health sense or in a highly individualized clinical or medico-legal sense. These issues are discussed and the profession is urged to reconsider and re-educate itself on these challenges.