[In vitro antimicrobial susceptibility of anaerobic bacteria isolated from pleuropulmonary infections]. / Susceptibilidad in vitro de bacterias anaeróbicas en infecciones pleuropulmonares.

BACKGROUND: Aspirative pleuropulmonary infections are usually caused by anaerobic flora of the mouth, mainly Prevotella, Fusobacterium and Peptostreptococcus spp. Penicillin in high doses is the traditional treatment for this type of infections but the rising resistance developed in recent years has induced the empiric use of clindamycin, increasing treatment costs. AIM: To study antimicrobial susceptibility of anaerobic bacteria isolated from pleuropulmonary infections. MATERIAL AND METHODS: Thirty two strains obtained from bronchoalveolar lavage and 15 strains isolated from pleural effusions between 2000 and 2002, were studied. The phenotype of strains was identified using the semiautomated API 20 A method and their susceptibility to penicillin (PNC), clindamycin (CM) and chloramphenicol (CAF) was tested using the E test methods. RESULTS: All the strains were susceptible to CAF, 95% to CM and 74.4% to PNC. The predominant genus was Prevotella, which also exhibited the higher resistance. CONCLUSIONS: As CM and CAF are active "in vitro", high rates of clinical response should be expected. In contrast, PNC is less effective, especially against pigmented Prevotella.

Susceptibilidad in vitro de bacterias anaeróbicas en infecciones pleuropulmonares / In vitro antimicrobial susceptibility of anaerobic bacteria isolated from pleuropulmonary infections

Background: Aspirative pleuropulmonary infections are usually caused by anaerobic flora of the mouth, mainly Prevotella, Fusobacterium and Peptostreptococcus spp. Penicillin in high doses is the traditional treatment for this type of infections but the rising resistance developed in recent years has induced the empiric use of clindamycin, increasing treatment costs. Aim: To study antimicrobial susceptibility of anaerobic bacteria isolated from pleuropulmonary infections. Material and methods: Thirty two strains obtained from bronchoalveolar lavage and 15 strains isolated from pleural effusions between 2000 and 2002, were studied. The phenotype of strains was identified using the semiautomated API 20 A method and their susceptibility to penicillin (PNC), clindamycin (CM) and chloramphenicol (CAF) was tested using the E test methods. Results: All the strains were susceptible to CAF, 95% to CM and 74.4% to PNC. The predominant genus was Prevotella, which also exhibited the higher resistance. Conclusions: As CM and CAF are active "in vitro", high rates of clinical response should be expected. In contrast, PNC is less effective, especially against pigmented Prevotella.

[In vitro susceptibility of streptococcus pneumoniae strains isolated from lower respiratory infections in Instituto Nacional del Tórax (INT)]. / Estudio de sensibilidad in vitro de cepas de Streptococcus pneumoniae de infecciones respiratorias bajas en el Instituto Nacional del Tórax (INT).

BACKGROUND: The rising antimicrobial resistance of streptococcus pneumoniae, requires permanent surveillance. Antimicrobial treatments of invasive infections must be modified accordingly. AIM: To assess the in vitro antimicrobial susceptibility of streptococcus pneumoniae strains isolated from lower respiratory infections. MATERIAL AND METHODS: Seventy five strains isolated during three periods in consecutive years were studied. In vitro susceptibility towards penicillin, erythromycin and ceftriaxone was studied using E-test technique minimal inhibitory concentrations. RESULTS: Five percent of strains were penicillin resistant and 11% had an intermediate sensitivity. Erythromycin resistance was observed in 1.3% of strains. Eight percent of strains had an intermediate sensitivity towards ceftriaxone and no resistance was observed. Comparing susceptibility in the three studied periods, it remained low and stable. CONCLUSIONS: High and intermediate resistance of Streptococcus pneumoniae towards penicillin is less prevalent than in other countries. A close surveillance must be maintained (Rev Méd Chile 2002; 130: 304-8).