Diagnostic value of pediatric blood culture bottles for acute postoperative endophthalmitis

OBJECTIVE: To report our experience using conventional culture methods (CM) and pediatric blood culture bottles (PBCBs) for vitreous sample culture of acute postoperative endophthalmitis. METHODS: A retrospective study was conducted at the Department of Ophthalmology, Hospital das Clinicas, HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, BR, from January 2010 to December 2015, and it included 54 patients with clinically suspected acute postoperative endophthalmitis. Vitreous samples were obtained by vitreous tap or vitrectomy. Samples from January 2010 to December 2011 were cultivated in CM, whereas samples from January 2012 to December 2015 were inoculated in PBCBs. The measured outcome was the yield of positive cultures. RESULTS: Twenty cases were included in the CM group, and 34 cases were included in the PBCB group. The yield of positive cultures in PBCBs (64.7%) was significantly higher than that in conventional CM (35%, p=0.034). Staphylococcus epidermidis and Streptococcus viridans were the two most commonly found agents. CONCLUSION: PBCBs can be used successfully in clinically suspected endophthalmitis. The method showed a higher yield of positive cultures than the conventional method. This technique appears to have several advantages over the traditional method: it saves time, as only one medium needs to be inoculated; transportation to a laboratory is easier than in the traditional method, and there is no need to maintain a supply of fresh agar media. The use of PBCBs may be recommended as the primary method for microbiological diagnosis and is especially suitable for office settings and remote clinics.

Stenotrophomonas maltophilia: resistência emergente ao SMX-TMP em isolados brasileiros: uma realidade / Stenotrophomonas maltophilia: emerging resistance to TMP-SMX in Brazilian isolate: a reality

INTRODUÇÃO: Stenotrophomonas maltophilia é um importante patógeno hospitalar emergente, naturalmente resistente aos carbapenêmicos, que possui sulfametoxazol/trimetoprima (SMX-TMP) como opção terapêutica. Porém, relatos de resistência a essa droga começaram a aparecer. OBJETIVO: Avaliar o perfil de sensibilidade das cepas de S. maltophilia e comparar os resultados obtidos por diferentes metodologias. MÉTODOS: As cepas isoladas na rotina microbiológica do Hospital das Clínicas de São Paulo em 2007 foram avaliadas quanto ao perfil de suscetibilidade por disco-difusão e microdiluição. Respeitando a padronização do Clinical and Laboratory Standard Institute (CLSI), SMX-TMP e levofloxacino foram testados pelas duas técnicas, bem como a tigeciclina, interpretada segundo a agência norte-americana Food and Drug Administration (FDA). Ticarcilina/clavulanato, ceftazidima, imipenem, meropenem e moxifloxacino foram avaliados apenas por microdiluição. O percentual de correlação entre as metodologias foi analisado pelo programa WHONET®. RESULTADOS: Das 126 cepas, 1,6 por cento apresentaram resistência a SMX-TMP; 2,4 por cento, a levofloxacino; 23 por cento, a ticarcilina/clavulanato; 54 por cento, a ceftazidima. Todas apresentaram concentração inibitória mínima (CIM) < 2 µg/mL para tigeciclina e 96,8 por cento, CIM < 2 µg/mL para moxifloxacino. O índice de concordância categórica entre as metodologias foi de 100 por cento para SMX-TMP e de 89,6 por cento para levofloxacino. DISCUSSÃO E CONCLUSÃO: Embora SMX-TMP seja a droga de escolha para o tratamento de infecções por S. maltophilia, há possibilidade de resistência a esse antibiótico, dificultando a decisão terapêutica empírica, sendo fundamental a realização do teste de sensibilidade. A técnica de disco-difusão demonstrou boa correlação com a microdiluição. Entre as novas opções terapêuticas, tigeciclina e moxifloxacino apresentaram boa atividade in vitro.

INTRODUCTION: Stenotrophomonas maltophilia is an important emerging nosocomial pathogen naturally resistant to carbapenems. Although trimethoprim/sulfamethoxazole (TMP-SMX) is commonly used as a treatment option, resistance to this drug has been recently reported. OBJECTIVE: To evaluate the susceptibility profile of S. maltophilia strains and compare the results obtained by different methods. METHODS: As to susceptibility profile, all strains, which had been routinely isolated at Hospital das Clínicas, São Paulo, in 2007, were evaluated through disk diffusion and microdilution. In accordance with the Clinical and Laboratory Standard Institute (CLSI), TMP-SMX and levofloxacin were tested through both techniques, as well as tigecycline, which was interpreted in conformity with Food and Drug Administration (FDA) regulations. Ticarcillin/clavulanate, ceftazidime, imipenem, meropenem and moxifloxacin were evaluated only through microdilution. The correlation between these methods was assessed by WHONET®. RESULTS: 1.6 percent of 126 strains were resistant to TMP-SMX, 2.4 percent to levofloxacin, 23 percent to ticarcillin/clavulanate, and 54 percent to ceftazidime. All strains showed minimum inhibitory concentration (MIC) < 2 µg/mL for tigecycline and 96.8 percent MIC < 2 µg/mL for moxifloxacin. The correlation index between both methods was 100 percent for TMP-SMX and 89.6 percent for levofloxacin, respectively. DISCUSSION AND CONCLUSION: Although TMP-SMX is the standard treatment for S. maltophilia infections, there may be resistance to this antibiotic, which hinders the therapeutic approach, hence the significance of susceptibility tests. The disk diffusion technique showed a good correlation with microdilution. Among the new therapeutic options, both tigecycline and moxifloxacin presented significant activity in vitro.