Biofilm formation and effect of caspofungin on biofilm structure of Candida species bloodstream isolates.

Candida biofilms are microbial communities, embedded in a polymeric matrix, growing attached to a surface, and are highly recalcitrant to antimicrobial therapy. These biofilms exhibit enhanced resistance against most antifungal agents except echinocandins and lipid formulations of amphotericin B. In this study, biofilm formation by different Candida species, particularly Candida albicans, C. tropicalis, and C. parapsilosis, was evaluated, and the effect of caspofungin (CAS) was assessed using a clinically relevant in vitro model system. CAS displayed in vitro activity against C. albicans and C. tropicalis cells within biofilms. Biofilm formation was evaluated after 48 h of antifungal drug exposure, and the effects of CAS on preformed Candida species biofilms were visualized using scanning electron microscopy (SEM). Several species-specific differences in the cellular morphologies associated with biofilms were observed. Our results confirmed the presence of paradoxical growth (PG) in C. albicans and C. tropicalis biofilms in the presence of high CAS concentrations. These findings were also confirmed by SEM analysis and were associated with the metabolic activity obtained by biofilm susceptibility testing. Importantly, these results suggest that the presence of atypical, enlarged, conical cells could be associated with PG and with tolerant cells in Candida species biofilm populations. The clinical implications of these findings are still unknown.

Evaluation of N95 respirator use as a tuberculosis control measure in a resource-limited setting.

SETTING: A 150-bed public Brazilian hospital that serves as reference hospital for tuberculosis (TB) patients. OBJECTIVE: To evaluate the use of personal respiratory protection by health care workers (HCWs) as a measure to reduce TB occupational risk. DESIGN: One hundred and forty-five HCWs were randomly observed for the use of a N95 respirator when entering high-risk areas or performing high-risk procedures. RESULTS: N95 respirators were infrequently used, even for high-risk procedures such as endotracheal intubation (25%) and respiratory aspiration (12%), and in high-risk areas such as the respirology ward (69.2%), emergency department (29.5%), intensive care unit (8.8%), and TB room isolation (39.5%). Facial-seal leakage was observed in 39% of HCWs due to failure to wear the mask with a tight facial fit as directed. CONCLUSION: Respirator use as a sole control measure is inadequate in any setting and is not cost-effective in resource-limited settings. Alternative or additional measures are clearly needed in hospitals with a high incidence of active TB admissions, specially following recent recommendations from the WHO, which consider personal respiratory protection as the third line of defense for TB control, indicated when TB risk cannot be adequately reduced by administrative and engineering controls.

Prospective surveillance applying the national nosocomial infection surveillance methods in a Brazilian pediatric public hospital.

BACKGROUND: A hospital-wide, traditional prospective surveillance for nosocomial infections was commenced in 1992 in Centro Geral de Pediatria in Minas Gerais, Brazil, to describe the epidemiology of nosocomial infection in this pediatric hospital and to implement cross-infection prevention and control policies. METHODS: We performed a prospective cohort nosocomial infection surveillance of all patients receiving acute care according to the hospital-wide and intensive care unit components of the National Nosocomial Infections Surveillance System from January 1993 to December 1997 (14,892 discharges; 131,764 patient-days). The Centers for Disease Control and Prevention (Atlanta) 1988-definitions and the Brazilian Ministry of Health-Legislation 930 (1992) were used. RESULTS: The average overall nosocomial infection rate per 1000 patient-days was 8.9 in units 2 and 3 and 16.4 in the pediatric intensive care unit. Over time, the overall hospital infection rate decreased from 16.6 nosocomial infections per 1000 patient-days in 1993 to 7.0 in 1997 (P <.05). We believe this can be attributed to interventions and data reporting during the period. The five most frequent sites of infections were eye-ear-nose-throat (38%), skin (22%), pneumonia (12%), soft tissue (5%) and laboratory-confirmed bloodstream infection (4%). In the pediatric intensive care unit, the most frequent nosocomial infection sites were pneumonia related to mechanical ventilators (22%), with rates ranging from 0 to 42 per 1000 ventilator-days; and sepsis related to central lines (11%), with rates ranging from 0 to 32 per 1000 central line-days. CONCLUSIONS: Describing the epidemiology of nosocomial infections in this hospital enabled us to establish infection occurrence, distribution, and expected incidence, as well as to recognize trends and keep track of possible outbreaks. The knowledge acquired through this surveillance allowed us to target more specific and continuous quality improvement projects, to upgrade health care quality in pediatric public hospitals in Brazil, and to implement preventive strategies. Methods from the National Nosocomial Infections Surveillance System can be successfully applied in pediatric public hospitals in Brazil.