Polymyxin use as a risk factor for colonization or infection with polymyxin-resistant Acinetobacter baumannii after liver transplantation.

INTRODUCTION: Acinetobacter baumannii is a leading agent of healthcare-associated infection. The objective of this study was to evaluate cases of colonization or infection with polymyxin-resistant A. baumannii (PRAB) in liver transplant recipients and to identify the risk factors for the acquisition of PRAB. METHODS: We evaluated all patients undergoing liver transplantation (LT) between January and November of 2011. The exclusion criterion was death within the first 72 h after transplant. Patients were screened for PRAB through weekly rectal and inguinal swabs during their stay in the intensive care unit (ICU) and at ICU discharge. Patients who came from other hospitals or had been treated in the emergency room for >72 h were screened at ICU admission. The minimum inhibitory concentrations (MICs) for polymyxins were determined by broth microdilution, and clonality was determined by pulsed-field gel electrophoresis. The stepwise logistic regression was used to identify risk factors related to acquisition of PRAB, and Cox forward regression used to identify risk factors for 60-day mortality. RESULTS: We evaluated 65 patients submitted to LT, among whom PRAB was isolated in 7, 4 of whom developed infection. The MICs for polymyxin E ranged from 16 to 128 mg/mL. All patients with PRAB required dialysis. The median time of polymyxin use before PRAB isolation was 21 days. These 4 included 1 case of primary bloodstream infection (BSI), which was treated with the carbapenem-polymyxin combination; 1 case of surgical site infection, which was treated with gentamicin, polymyxin, ampicillin-sulbactam, and tigecycline; and 2 cases of pneumonia, treated with the combination of carbapenem-polymyxin. In the case of BSI and in 1 of the cases of pneumonia, the treatment was considered successful. Mortality was 71% among the cases, compared with 33% among the non-cases. CONCLUSION: In the final model of the survival analysis, PRAB colonization or infection after LT was independently associated with mortality. One predominant clone was identified. The only risk factor identified in the multivariate analysis was polymyxin use. PRAB was an agent with high mortality, and the most important risk factor associated with colonization or infection for such bacterium was polymyxin use.

Candida colonisation as a source for candidaemia.

Candida spp. are important healthcare-associated pathogens. Identifying the source of infection is important for prevention and control strategies. The objective of this study was to evaluate candida colonisation sites as potential sources for candidaemia. Sixty-three consecutive patients with a positive blood culture for candida were included. Surveillance cultures were collected from urine, rectum, oropharynx, skin, intravascular catheter tip and skin around catheter. Molecular typing was performed when the same species of candida was isolated from blood and surveillance sites of a patient. C. albicans was associated with 42% of candidaemias, C. parapsilosis 33%, C. tropicalis 16% and C. guilliermondii, C. krusei, C. glabrata, C. holmii and C. metapsilosis were all 2% each. Six of 10 C. parapsilosis catheter tip isolates were indistinguishable from corresponding blood isolates (all in neonates). C. albicans isolates from blood were indistinguishable from corresponding gastrointestinal tract isolates in 13 of 26 patients and from catheter tip isolates in two patients. In conclusion, the results suggest that gastrointestinal colonisation is the probable source of C. albicans candidaemia and C. parapsilosis is exogenous.

A nosocomial outbreak of Salmonella enteritidis associated with lyophilized enteral nutrition.

Outbreaks of Salmonella spp. gastro-enteritis in hospitals are of concern because of the increased susceptibility of patients and associated high morbidity. This study is a report of a nosocomial outbreak of Salmonella enteritidis associated with enteral nutrition. In December 1999, one sample of enteral feed tested positive for S. enteritidis. During the subsequent 6 weeks, eight cases of nosocomial salmonellosis occurred. Patients involved in the outbreak were aged 19-79 years (median = 36.5), and salmonella was isolated from the blood of two patients. All patients were receiving enteral nutrition at the time and all had diarrhoea. Three patients died. All 13 employees of the Nutrition Department were asymptomatic and their stool samples were negative. Environmental and water samples were also negative. The diet, however, contained lyophilized egg albumin. Molecular typing showed that the isolates of seven patients were indistinguishable from the one obtained from the enteral diet. It was thought that the nosocomial salmonellosis probably occurred due to the use of a commercial lyophilized diet. Another method of processing diets may be necessary to ensure patient safety.