Acinetobacter baumannii ventilator-associated pneumonia: epidemiology, clinical characteristics, and prognosis factors.

OBJECTIVE: The aim of this study was to describe the epidemiological characteristics of Acinetobacter baumannii ventilator-associated pneumonia (VAP) and to identify factors predictive of a poor outcome. METHODS: A retrospective study was conducted over 16 months in a Tunisian intensive care unit (ICU). All adult patients with A. baumannii VAP were included. RESULTS: Ninety-two patients were included in they study; 41 (44.6%) were admitted because of multiple trauma. The mean age of the patients was 44.5±19.5 years. All patients needed mechanical ventilation on admission. The mean SAPS II score was 39±15. The mean delay before VAP onset was 8.1±4.7 days. On VAP onset, 57 patients (62%) developed septic shock. Only 14.2% of isolated strains were susceptible to imipenem; none were resistant to colistin. The mean duration of mechanical ventilation was 20±11 days. The mean duration of ICU stay was 24.3±18.7 days. ICU mortality was 60.9%. In the multivariate analysis, factors predictive of a poor outcome were previously known hypertension (odds ratio 5.8, 95% confidence interval 1.4-24.9; p=0.018) and VAP-related septic shock (odds ratio 8.5, 95% confidence interval 3-23.7; p<0.001). CONCLUSION: A. baumannii VAP is associated with a high mortality. Hemodynamic impairment is predictive of a poor outcome.

Microbiological characteristics of catheter-related bacteremia in a Tunisian intensive care unit.

BACKGROUND: Prevalence of catheter-related bacteremia in intensive care units is increasing as central venous catheters (CVC) are used more frequently. In the most of the published literature, Gram positive cocci are the leading cause of catheter-related bacteremia and the systemic empiric treatment recommended include the administration of glycopeptides. AIM: To search for the microbiological characteristics of catheter-related bacteremia in a Tunisian ICU. METHODS: Prospective observational cohort survey conducted in the ICU of the Habib Bourguiba university hospital, Tunisia (a 22 bed medical-surgical intensive care unit). We had included all patients admitted to the unit over the study period (from August 1st, 2001 to March 31st, 2002), and who submitted to a central venous catheter for more than 24 hours. Catheter-tip specimens were cultured using a semiquantitative method. RESULTS: During the study period 218 central venous catheters (CVC) were assessed. The mean length of time the catheter was kept in place was 8±6.7 days (range; 2 and 46 days). The CVC insertion site was the subclavian vein in 156 cases (71.6%), the jugular vein in 35 cases (16%), and the femoral vein in 27 cases (12.4%). Seventy four catheters (33.9%) were removed because of suspicion of catheter-related sepsis. The catheter-related bacteremia rate was 6.1 infections/1000 days-CVC. Unlike Gram-positive cocci which caused only one case of catheter-related bacteremia, Gram-negative rods, namely Klebsiella pneumoniae and Serratia marcescens were responsible for 91.7% of cases of catheter-related bacteremia. CONCLUSION: Our findings translate a specific microbiological flora in our Tunisian intensive care unit and highlight the importance of a treatment strategy based on local epidemiology in patients with catheter related bacteremia.

Correlation between antibiotic use and changes in susceptibility patterns of Pseudomonas aeruginosa in a medical-surgical intensive care unit.

CONTEXT: Multiple surveillance programmes have reported a decline in antibiotic susceptibility of P. aeruginosa. AIM: Our study aimed to study the relationship between the use of antipseudomonal drugs and the development of resistance of P. aerogenosa to these drugs. SETTING AND DESIGN: Our study is retrospective. It was conducted in a medical surgical intensive care unit during a five-year period (January 1(st), 1999 to December 31, 2003), which was divided into 20 quarters. We had monitored the use of antipseudomonal agents and the resistance rates of P. aeruginosa to these drugs. STATISTICAL METHODS: The associations between use and resistance were quantified using non-partial and partial correlation coefficients according to Pearson and Spearman. RESULTS: Over the study period, the most frequently used antipseudomonal agent was Imipenem (152 +/- 46 DDD/1000 patients-day) and the resistance rate of P. aeruginosa to Imipenem was 44.3 +/- 9.5% (range, 30 and 60%). In addition, Imipenem use correlated significantly with development of resistance to Imipenem in the same (P < 0.05) and in the following quarter (P < 0.05); and Ciprofloxacin use correlated significantly with resistance to Ciprofloxacin in the following quarter (P < 0.05). However, use of Ceftazidime or Amikacine had no apparent association with development of resistance. CONCLUSION: We conclude that the extensive use of imipenem or ciprofloxacin in intensive care units may lead to the emergence of imipenem- and ciprofloxacin-resistant strains of P. aeruginosa and that antibiotic prescription policy has a significant impact on P. aeruginosa resistance rates in an intensive care unit.

Emergence of multidrug-resistant Klebsiella pneumoniae isolates producing VIM-4 metallo-beta-lactamase, CTX-M-15 extended-spectrum beta-lactamase, and CMY-4 AmpC beta-lactamase in a Tunisian university hospital.

Klebsiella pneumoniae clinical isolates resistant to carbapenems were recovered from 11 patients in the hospital of Sfax, Tunisia. The isolates were closely related as shown by pulsed-field gel electrophoresis, and they produced VIM-4 metallo-enzyme, CTX-M-15 extended-spectrum beta-lactamase, and CMY-4 AmpC enzyme. The bla(VIM-4) gene is part of a class 1 integron.

Endocarditis due to Kytococcus schroeteri: case report and review of the literature.

We report the third case of endocarditis caused by the newly described micrococcal species Kytococcus schroeteri. A 49-year-old woman was admitted to the hospital with suspected prosthetic valve endocarditis. Five blood cultures and prosthetic valve cultures grew the same type of organism, initially identified as Micrococcus sp. Assignment to the genus Kytococcus was suggested by the arginine dihydrolase activity and resistance to oxacillin. After sequencing of the 16S rRNA genes, the isolate was recognized as K. schroeteri. The patient was treated first with vancomycin combined with gentamicin and later with pristinamycin and rifampin. Three cases of K. schroeteri endocarditis described within a short period of time might indicate a specific pathogenicity of this new species. The isolation of kytococci from normally sterile sites should not be overlooked.