Cotrimoxazole Prophylaxis Specifically Selects for Cotrimoxazole Resistance in Streptococcus mutans and Streptococcus sobrinus with Varied Polymorphisms in the Target Genes folA and folP

The selection of antibiotic resistance by cotrimoxazole prophylaxis was evaluated, and we characterized the mechanism of cotrimoxazole resistance in Streptococcus mutans and Streptococcus sobrinus. In vitro susceptibility to six antibiotics was evaluated on 64 mutans streptococci group (MSG) isolates from a cotrimoxazole prophylaxis group and compared to 84 MSG isolates from a nonprophylaxis group. The folA and folP genes were sequenced and compared with reference sequences at NCBI. Only resistance to cotrimoxazole was significantly higher in the prophylaxis group (54.7% versus 15.5%, OR = 6.59, 95% CI: 2.89–15.3, P < 0.05). Resistance to amoxicillin, ceftriaxone, chloramphenicol, erythromycin, and tetracycline was 1.4%, 25.5%, 6.2%, 6.5%, and 29.6% of the isolates, respectively. Considerable polymorphisms were found in the folP gene in S. mutans, but this could not be linked to sulfonamide drug resistance. No variation was seen in folP or folA genes of S. sobrinus. Genetic transfer of folate pathway genes seems unlikely in these isolates

Prevalence and factors associated with dental caries among children and adults in selected districts in Uganda

Objective: The aim was to determine the prevalence and factors associated with dental caries among adults and children in seven districts of Uganda.Methods: Participants aged 11-13 (n=1230) and 35-44 years (n=648) were randomly selected from urban and rural areas of Gulu, Soroti, Jinja, Masaka, Kabale, Kabarole and Hoima districts. They were examined by 4 trained and calibrated dentists for dental caries using Decayed, Missing and Filled teeth index as described by World Health Organisation.Results: Overall mean DMFT score was 0.73 for children and 4.71 for adults. Generally, there was a higher mean DMFT score in the rural (2.19) compared to urban areas (1.97). In all the districts, except Hoima, there was a higher mean DMFT score of children in rural compared to urban. In adults, similar trend was mainly registered in Masaka, Hoima and Gulu districts. Most participants (79.9%, n=1309) occasionally ate sugared snacks. Overall, 95% (n=1795) of the participants cleaned their teeth with plastic tooth brushes (71.7%) and chewing sticks (8.3%).Conclusion: Although the severity of dental caries was low, the disease was widespread in the study population. A high proportion of participants reported consumption of sugared snacks and drinks, which calls for oral health education.Keywords: Dental caries prevalence, severity, sugared snacks, tooth brushing, Ugand

The Relationships Between Fluoride Intake Levels and Fluorosis of Late‐Erupting Permanent Teeth

Objectives To examine the relationships between fluoride intake levels and fluorosis of late‐erupting permanent teeth. Methods The current study used information collected from 437 children in the longitudinal Iowa Fluoride Study. Participants\u27 fluoride intake information was collected using questionnaires from birth to age 10 years. Estimated mean daily fluoride intake was categorized into low, moderate, and high intake tertiles for each age interval (2‐5, 5‐8, and 2‐8 years). Bivariate analyses were performed to study the relationships between self‐reported fluoride intake levels during three age intervals and dental fluorosis. Results For canines and second molars, the prevalence of mostly mild fluorosis was less than 10% in the lowest fluoride intake tertile and more than 25% in the highest intake tertile. For both first and second premolars, the prevalence in the low and high intake tertiles was approximately 10‐15% and 25‐40%, respectively. When estimated total daily fluoride intake was 0.04 mg/kg BW during ages 2‐8 years, the predicted probability of fluorosis was 16.0%, 20.5%, 21.8%, and 15.4% for canines, 1st and 2nd and premolars and 2nd molars, respectively. We found that an incremental increase in fluoride intake during the age 5‐ to 8‐year interval led to greater odds for development of mostly mild dental fluorosis in late‐erupting teeth compared to increases in fluoride intake during other age intervals. Conclusions Our results clearly show that dental fluorosis prevalence is closely related to fluoride intake levels and that teeth have greater susceptibility to fluoride intake during certain age intervals

Prevalence and factors associated with dental caries among children and adults in selected districts in Uganda

Objective: The aim was to determine the prevalence and factors associated with dental caries among adults and children in seven districts of Uganda. Methods: Participants aged 11-13 (n=1230) and 35-44 years (n=648) were randomly selected from urban and rural areas of Gulu, Soroti, Jinja, Masaka, Kabale, Kabarole and Hoima districts. They were examined by 4 trained and calibrated dentists for dental caries using Decayed, Missing and Filled teeth index as described by World Health Organisation. Results: Overall mean DMFT score was 0.73 for children and 4.71 for adults. Generally, there was a higher mean DMFT score in the rural (2.19) compared to urban areas (1.97). In all the districts, except Hoima, there was a higher mean DMFT score of children in rural compared to urban. In adults, similar trend was mainly registered in Masaka, Hoima and Gulu districts. Most participants (79.9%, n=1309) occasionally ate sugared snacks. Overall, 95% (n=1795) of the participants cleaned their teeth with plastic tooth brushes (71.7%) and chewing sticks (8.3%). Conclusion: Although the severity of dental caries was low, the disease was widespread in the study population. A high proportion of participants reported consumption of sugared snacks and drinks, which calls for oral health education

Prediction of width of un-erupted incisors, canines and premolars in a Ugandan population: A cross sectional study

Abstract Background Accurate prediction of the space forms an important part of an orthodontic assessment in the mixed dentition. However the most commonly used methods of space analysis are based on data developed on Caucasian populations. In order to provide more accurate local data we set out to develop a formula for predicting the widths of un-erupted canines and premolars for a Ugandan population and to compare the predicted widths of the teeth from this formula with those obtained from Moyers’ tables, and Tanaka and Johnston’s equations. Methods Dental casts were prepared using mandibular and maxillary arch impressions of 220 children (85 boys/135 girls) aged 12–17 years recruited from schools in Kampala, Uganda. The mesio-distal width of the mandibular incisors, mandibular and maxillary canines and premolars were measured with a pair of digital calipers. Based on regression analysis, predictive equations were derived and the findings were compared with those presented in Moyers’ probability tables, and Tanaka and Johnston’s equations. Results There were no statistically significant differences between the tooth widths predicted by our equations and those from Moyers’ probability tables at the 65th and 75th percentile probabilities for the girls and at 75th level in boys in the mandibular arch. While in the maxillary arch no statistically significant differences at the 75th and 95th levels were noted in girls. There were statistically significant differences between predicted tooth sizes using equations from the present study and those predicted from the Tanaka and Johnston regression equations. Conclusions In this Ugandan population, Moyers’ probability tables could be used to predict tooth widths at specific percentile probabilities, but generally, Tanaka and Johnston technique tends to overestimate the tooth widths.</p

Knowledge and Antibiotics Prescription Pattern among Ugandan Oral Health Care Providers: A Cross-sectional Survey

Background and aims. Irrational prescription of antibiotics by clinicians might lead to drug resistance. Clinicians do prescribe antibiotics for either prophylactic or therapeutic reasons. The decision of when and what to prescribe leaves room for misuse and therefore it is imperative to continuously monitor knowledge and pattern of prescription. The aim of the present study was to determine the knowledge of antibiotic use and the prescription pattern among dental health care practitioners in Uganda. Materials and methods. A structured and pretested questionnaire was sent to 350 dental health care practitioners by post or physical delivery. All the questionnaires were sent with self-addressed and prepaid postage envelopes to enable respondents to mail back the filled questionnaires. Chi-squared test was used to test for any significant differences between groups of respondents based on qualitative variables. Results. The response rate was 40.3% (n=140). Of these 52.9 % were public health dental officers (PHDOs) and 47.1% were dental surgeons. The males constituted 74.3% of the respondents. There were statistically significant differences between dental surgeons and (PHDOs) in knowledge on prophylactic antibiotic use (P = 0.001) and patient influence on prescription (P = 0.001). Amoxicillin, in combination with metronidazole, was the most common combination of antibiotics used followed by co-trimoxazole with metronidazole. Conclusion. The knowledge of dental health care practitioners in antibiotic use in this study was generally low. A combination of amoxicillin with metronidazole was the most commonly prescribed antibiotics subsequent to different dental procedures

Point Mutations in the folP Gene Partly Explain Sulfonamide Resistance of Streptococcus mutans

Cotrimoxazole inhibits dhfr and dhps and reportedly selects for drug resistance in pathogens. Here, Streptococcus mutans isolates were obtained from saliva of HIV/AIDS patients taking cotrimoxazole prophylaxis in Uganda. The isolates were tested for resistance to cotrimoxazole and their folP DNA (which encodes sulfonamide-targeted enzyme dhps) cloned in pUC19. A set of recombinant plasmids carrying different point mutations in cloned folP were separately transformed into folP-deficient Escherichia coli. Using sulfonamide-containing media, we assessed the growth of folP-deficient bacteria harbouring plasmids with differing folP point mutations. Interestingly, cloned folP with three mutations (A37V, N172D, R193Q) derived from Streptococcus mutans 8 conferred substantial resistance against sulfonamide to folP-deficient bacteria. Indeed, change of any of the three residues (A37V, N172D, and R193Q) in plasmid-encoded folP diminished the bacterial resistance to sulfonamide while removal of all three mutations abolished the resistance. In contrast, plasmids carrying four other mutations (A46V, E80K, Q122H, and S146G) in folP did not similarly confer any sulfonamide resistance to folP-knockout bacteria. Nevertheless, sulfonamide resistance (MIC = 50 μM) of folP-knockout bacteria transformed with plasmid-encoded folP was much less than the resistance (MIC = 4 mM) expressed by chromosomally-encoded folP. Therefore, folP point mutations only partially explain bacterial resistance to sulfonamide