Epidemiologia molecular de Staphylococcus aureus em pacientes acamados em domicílio ou vivendo em instituições de longa permanência para idosos no município de Botucatu, SP.
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Data
2019-02-27
Autores
Silva, Lucas Porangaba
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Universidade Estadual Paulista (Unesp)
Resumo
A epidemiologia das infecções estafilocócicas tem sofrido importante modificação nas últimas décadas. A emergência de linhagens de Staphylococcus aureus resistentes à meticilina associados à comunidade (CA-MRSA) representa risco especial para populações reconhecidamente vulneráveis como os idosos. Neste âmbito, duas situações distintas são de especial interesse: os indivíduos institucionalizados, vivendo em casas de repouso, que representam um espaço intermediário entre a comunidade e o hospital; e os dependentes (acamados) cuidados em domicílio, expostos de forma intermitente aos serviços de saúde. Nosso objetivo foi identificar a prevalência e fatores associados ao carreamento nasal, oral e retal de S. aureus e MRSA em indivíduos acamados ou residindo em instituições de longa permanência para idosos (ILPIs) no município de Botucatu, SP, bem como a identificação de clones importantes de S. aureus e MRSA nessa população. Estudo com delineamento transversal, em que swabs da nasofaringe, orofaringe e reto de 226 indivíduos (150 residentes em nove ILPIs e 76 acamados em domicílio) foram coletados juntamente com um questionário que, através de entrevista com o próprio indivíduo ou responsável legal, levantou informações como dados demográficos (gênero e idade), tempo de institucionalização ou restrição ao leito, dados clínicos (comorbidades), dispositivos invasivos, internações recentes, doenças infeccionas e uso de antimicrobianos, para identificação dos fatores de risco. O isolamento de S. aureus foi realizado em Ágar Baird Parker e a identificação foi realizada por provas bioquímicas e confirmação genotípica. Para detecção do gene mecA utilizou-se PCR, caracterização do SCCmec por PCR Multiplex e tipagem molecular dos MRSA pela técnica de PFGE (Pulsed Field Gel Electrophoresis). A prevalência global de S. aureus identificada foi de 76 (33,6%) e 18 (8%) de MRSA. Quanto aos idosos das nove ILPIs, a prevalência de S. aureus variou de 16,6% a 85,7% e a de MRSA de 13,3% a 25%. Dos 76 indivíduos acamados 20 (26,3%) estavam colonizados com S. aureus e desses, quatro (5,2%) eram portadores de MRSA. Dos 20 MRSA, seis carreavam o SCCmec do tipo IV, nove com SCCmec do tipo II e um com SCCmec tipo I. A análise estatística multivariada dos fatores de risco para carreamento de S. aureus nos indivíduos incluídos no estudo (acamados e idosos residentes em ILPIs) revelou associação positiva com residentes em ILPIs (OR=2,05, IC95%=1,07-3,91, p=0,03), com o sexo masculino (OR=2,15, IC95%=1,22-3,79, p=0,008), com histórico de cirurgias (OR=5,99, IC95%=1,26-28,92, p=0,02), com a presença de comorbidades pelo Charlson score (OR=1,35, IC95%=1,01-1,92, p=0,047) e associação negativa com doenças cardíacas (OR=0,18, IC95%=0,05-0,70, p=0,01). Para o carreamento de MRSA a análise multivariada revelou associação positiva com sexo masculino (OR=3,29, IC95%=1,18-9,17, p=0,02). A tipagem por PFGE dos MRSA revelou a presença de cinco clusters, sendo que a maioria agrupou isolados da ILPI de maior porte, e com similaridade com MRSA de diferente ILPI. Os resultados do PFGE também mostraram similaridade entre MRSA isolado de indivíduo acamado e de ILPI. Com os dados obtidos é possível compreender melhor a epidemiologia de S. aureus e MRSA na população estudada. Os resultados descritos ressaltam o papel que as instituições de pequeno e médio porte desempenham pela alta prevalência de MRSA que possuem. Além disso, o alto número de MRSA de origem oral mostra a importância de estudar esse sítio geralmente negligenciado.
The epidemiology of staphylococcal infections has undergone important changes in recent decades. The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains represents a special risk to populations recognized as vulnerable, such as the elderly. Within this context, two different situations are of special interest: institutionalized individuals living in nursing homes, which represent an intermediary space between the community and the hospital, and dependent (bedridden) patients cared for at home, who are intermittently exposed to health services. Our objective was to determine the prevalence and factors associated with nasal, oral and rectal carriage of S. aureus and MRSA in bedridden patients and residents of long-term care facilities (LTCF) for the elderly in the city of Botucatu, SP, and to identify important S. aureus and MRSA clones in this population. In a cross-sectional study, nasopharyngeal, oropharyngeal and rectal swab samples were collected from 226 individuals (150 individuals from nine LTCF and 76 bedridden patients living at home). In addition, a questionnaire was applied by interview with the subject himself or the legal representative for the collection of demographic data (gender and age), length of institutionalization or bedridden period, clinical data (comorbidities), invasive devices, recent hospitalizations, infectious diseases, and antimicrobial use in order to identify risk factors. Staphylococcus aureus was isolated on Baird Parker agar and identified by biochemical tests and genotypic confirmation. PCR was used for detection of the mecA gene and multiplex PCR for characterization of SCCmec. Molecular typing of MRSA was performed by pulsed field gel electrophoresis (PFGE). The overall prevalence of S. aureus was 33.6% (n = 76) and that of MRSA was 8% (n = 18). Among the elderly individuals from the nine LTCF, the prevalence of S. aureus ranged from 16.6 % to 85.7% and that of MRSA from 13.3% to 25.0%. Twenty (26.3%) of the 76 bedridden individuals were colonized with S. aureus and four of them (5.2%) were carriers of MRSA. Among the 20 MRSA isolates, six harbored SCCmec Type IV, nine SCCmec Type II, and one SCCmec Type I. Multivariate analysis of risk factors for S. aureus carriage in the individuals included in the study (bedridden patients and elderly residents of LTCF) revealed a positive association with residency in LTCF (OR=2.05, 95%CI=1.07-3.91, p=0.03), male gender (OR=2.15, 95%CI=1.22-3.79, p=0.008), history of surgeries (OR=5.99, 95%CI=1.26-28.92, p=0.02) and presence of comorbidities according to the Charlson score (OR=1.35, 95%CI=1.01-1.92, p=0.047), and a negative association with heart diseases (OR=0.18, 95%CI=0.05-0.70, p=0.01). For MRSA carriage, multivariate analysis showed a positive association with male gender (OR=3.29, 95%CI=1.18-9.17, p=0.02). Typing of MRSA by PFGE revealed the presence of five clusters. Most clusters contained isolates from larger LTCF and similarity was observed between MRSA from different LTCF. The PFGE results also showed similarity between MRSA isolated from bedridden patients and LTCF residents. The results contribute to a better understanding of the epidemiology of S. aureus and MRSA in the population studied. The findings emphasize the role of small and medium-sized institutions due to the high prevalence of MRSA found. In addition, the large number of MRSA of oral origin highlights the importance of studying this generally neglected site.
The epidemiology of staphylococcal infections has undergone important changes in recent decades. The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains represents a special risk to populations recognized as vulnerable, such as the elderly. Within this context, two different situations are of special interest: institutionalized individuals living in nursing homes, which represent an intermediary space between the community and the hospital, and dependent (bedridden) patients cared for at home, who are intermittently exposed to health services. Our objective was to determine the prevalence and factors associated with nasal, oral and rectal carriage of S. aureus and MRSA in bedridden patients and residents of long-term care facilities (LTCF) for the elderly in the city of Botucatu, SP, and to identify important S. aureus and MRSA clones in this population. In a cross-sectional study, nasopharyngeal, oropharyngeal and rectal swab samples were collected from 226 individuals (150 individuals from nine LTCF and 76 bedridden patients living at home). In addition, a questionnaire was applied by interview with the subject himself or the legal representative for the collection of demographic data (gender and age), length of institutionalization or bedridden period, clinical data (comorbidities), invasive devices, recent hospitalizations, infectious diseases, and antimicrobial use in order to identify risk factors. Staphylococcus aureus was isolated on Baird Parker agar and identified by biochemical tests and genotypic confirmation. PCR was used for detection of the mecA gene and multiplex PCR for characterization of SCCmec. Molecular typing of MRSA was performed by pulsed field gel electrophoresis (PFGE). The overall prevalence of S. aureus was 33.6% (n = 76) and that of MRSA was 8% (n = 18). Among the elderly individuals from the nine LTCF, the prevalence of S. aureus ranged from 16.6 % to 85.7% and that of MRSA from 13.3% to 25.0%. Twenty (26.3%) of the 76 bedridden individuals were colonized with S. aureus and four of them (5.2%) were carriers of MRSA. Among the 20 MRSA isolates, six harbored SCCmec Type IV, nine SCCmec Type II, and one SCCmec Type I. Multivariate analysis of risk factors for S. aureus carriage in the individuals included in the study (bedridden patients and elderly residents of LTCF) revealed a positive association with residency in LTCF (OR=2.05, 95%CI=1.07-3.91, p=0.03), male gender (OR=2.15, 95%CI=1.22-3.79, p=0.008), history of surgeries (OR=5.99, 95%CI=1.26-28.92, p=0.02) and presence of comorbidities according to the Charlson score (OR=1.35, 95%CI=1.01-1.92, p=0.047), and a negative association with heart diseases (OR=0.18, 95%CI=0.05-0.70, p=0.01). For MRSA carriage, multivariate analysis showed a positive association with male gender (OR=3.29, 95%CI=1.18-9.17, p=0.02). Typing of MRSA by PFGE revealed the presence of five clusters. Most clusters contained isolates from larger LTCF and similarity was observed between MRSA from different LTCF. The PFGE results also showed similarity between MRSA isolated from bedridden patients and LTCF residents. The results contribute to a better understanding of the epidemiology of S. aureus and MRSA in the population studied. The findings emphasize the role of small and medium-sized institutions due to the high prevalence of MRSA found. In addition, the large number of MRSA of oral origin highlights the importance of studying this generally neglected site.
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Palavras-chave
População idosa, Pacientes acamados, Staphylococcus aureus, MRSA, Epidemiologia molecular, Elderly population, Bedridden patients, Staphylococcus aureus, , Molecular epidemiology