Antimicrobial resistance and genetic diversity of Escherichia coli isolated from humans and foods

Antibiotic resistance has increased in recent years, raising the concern of public health authorities. We conducted a study of Escherichia coli isolates obtained from human and food samples to assess the prevalence of antimicrobial resistance and to determine the genotype and clonal relationship of 84 E. coli isolates (48 from humans and 36 from foods). An antimicrobial susceptibility test was performed using the disk diffusion method. Virulence factors were evaluated by multiplex PCR, and the clonal relationship among the resistant isolates was studied by Pulsed Field Gel Electrophoresis (PFGE). All isolates were susceptible to ceftriaxone. Overall, 26%, 20.2%, 15.4% and 6% of the isolates were resistant to tetracycline, ampicillin, sulfamethoxazole/trimethoprim and cephalotin, respectively. Twenty two percent of the isolates exhibited resistance to more than one antimicrobial agent. Multiple-drug resistance was mostly observed in the human isolates and involved the antibiotics ampicillin and tetracycline. None of the six virulence genes were identified among the isolates. Analysis of genetic diversity by PFGE of 31 resistant isolates, revealed 29 distinct restriction patterns. In conclusion, E. coli from humans and foods are resistant to commonly used antibiotics and are highly genetically diverse. In this setting, inappropriate use of antibiotics may be a cause of high resistance rate instead of clonal spread.

Colonização Nasofaringeana por streptococcus pneumoniae: estudo lngitudinal em crianças menores de cinco anos de idade / Colonization nasopharyngeal by Streptococcus pneumoniae: longitudinal study in children under Five years old

Streptococcus pneumoniae é um dos agentes etiológicos mais importantes em infecções adquiridas na comunidade. Este patógeno coloniza o trato respiratório de indivíduos saudáveis, apresentando maior prevalência entre 1 e 2 anos de idade (aproximadamente 50%) e depois diminui com a idade adulta (aproximadamente 10%). A alta incidência das doenças pneumocócicas e a crescente resistência aos antimicrobianos, favoreceu a introdução das vacinas conjugadas (ano de 2000). Após a introdução das vacinas conjugadas foi observado à queda na incidência da doença pneumocócica e diminuição da prevalência de colonização por sorotipos vacinais. Em contrapartida vem sendo notado o aumento de casos de doença sorotipos não vacinais. Por isso a importância de verificar a dinâmica da colonização nasofaringeana por pneumococos em crianças < 5 anos de idade antes da introdução da vacina. Foram selecionadas radomicamente 203 crianças residentes da comunidade de Pau da Lima, Salvador, Bahia, das quais foi colhido a amostra nasofaringeana em quatro períodos durante um ano com intervalo de três a quatro meses entre cada coleta. No período de janeiro de 2008 a janeiro de 2009 foram colhidos um total de 721 swabs, sendo 398 positivos para pneumococos (56%)...

Streptococcus pneumoniae is one of the most important etiologic agents in community-acquired infections. This pathogen colonizes the respiratory tract of healthy individuals shortly after birth, with higher prevalence of between 1 and 2 years of age (approximately 50%) and then decreases with age reaching adult rates below 10%. The high incidence and increasing antimicrobial resistance, favored the introduction of conjugate vaccines in 2000. After the introduction of conjugate vaccines a decreasing incidence of pneumococcal disease and carriage rates by vaccine serotypes was observed. In contrast we observe an increase in number of cases of disease and carriage by non-vaccine serotypes. Thus, this study aims to determine the dynamics of nasopharyngeal colonization by pneumococci in children <5 years of age after introduced the conjugate vaccine. A total of 203 children were random selected at the community of Pau da Lima in Salvador, Bahia, of whom the nasopharyngeal swab was collected in four periods with interval of 3 to 4 months between each collection. A total of 721 swabs were collected from January 2008 to January 2009, with 398 positive for pneumococci (56%)...

Avaliação qualitativa e quantitativa de streptococcus mutans na saliva de pacientes em tratamento ortodôntico com aparelhos removíveis / Qualitative and quantitative evaluation of streptococcus mutans in saliva of patients undergoing orthodontic treatment with removable appliances

O objetivo do trabalho é avaliar os níveis salivares de streptococcus mutans, antes e durante o tratamento ortodôntico com aparelhos removíveis. A amostra foi constituída de 19 pacientes em terapia Ortodontia preventiva e interceptativa. Para tanto, foram realizadas coletas de saliva 15 dias antes e 45 dias após a instalação do aparelho. A saliva coletada passou por análise microbiológica, através do meio MSB, para identificação e contagem bacteriana; para confirmação da espécie foram realizadas provas bioquímicas com a fermentação de manitol, sorbitol e rafinose. Foi observado que dos 19 pacientes, 73,68% apresentaram aumento estatisticamente significativo (p < 0,05) na contagem de streptococcus mutans, e 26,31% apresentaram redução. Em relação ao risco de cárie dental, 68% dos pacientes foram classificados em alto risco devido às contagens superiores a 250.000 (105) UFC/ml de saliva. A elevada taxa de colonização por streptococcus mutans associada ao uso de aparelhos ortodônticos removíveis pode não ser necessariamente preditiva de cáries em desenvolvimento, mas sublima a necessidade de medidas preventivas durante todo o período de tratamento ortodôntico.

The aim of the study was to evaluate salivary levels of streptococcus mutans, before and during orthodontic treatment with removable appliances. The sample consisted of 19 patients undergoing Preventive and Interceptive Orthodontic therapy. For this purpose, saliva was collected 15 days before and 45 days after placement of the appliance. The saliva collected was submitted to microbiological analysis by means of MSB, for identification and quantification of bacterial count; and for confirmation of species, biochemical assays were performed with mannitol, sorbitol and raffinose fermentation. It was observed that of the 19 patients, 73.68% presented statistically significant increase (p < 0.05) in streptococcus mutans count, and 26.31% presented reduction. As regards risk for dental caries, 68% of the patients were classified as high risk due to counts exceeding 250,000 (105) CFU/ml of saliva. The high rate of colonization by streptococcus mutans associated with the use of removable orthodontic appliances may not necessarily be predictive of caries in development, but increases the need for preventive measures during the entire period of orthodontic treatment.