Organisms cultured and resistance patterns seen in a secondary referral centre ICU and burns unit

摘要

BACKGROUND: Infections are common in intensive care units (ICUs) and burns units. Empiric antibiotic therapy is often required, and as such it is important to have a good knowledge of the resident organisms in these departments. Antibiotic resistance is becoming an increasing problem both internationally and in South Africa (SA) and it is important to monitor organism sensitivity. OBJECTIVES: To establish the spectrum and sensitivity of nosocomial pathogens in an SA government referral hospital ICU and burns unit. METHODS: We report the findings from a retrospective audit of all cultures sent from the ICU and burns unit of an SA urban hospital for a 6-month period between January and June 2008. RESULTS: The results showed a prevalence of Gram-negative organisms in the ICU department, in particular Klebsiella pneumoniae and Escherichia coli. There was a prevalence of Gram-positive organisms in the burns unit. Overall resistance to co-amoxiclav and erythromycin was found to be high (49% and 53%, respectively), resistance to ciprofloxacin and gentamicin was moderate (30% and 35%, respectively) and resistance to piperacillin-tazobactam and the carbapenems remained low (21% for piperacillin-tazobactam, 2% for ertapenem and 19% for meropenem). When looking at individual species, it was noted that K. pneumoniae had high resistance to ampicillin (97%), moderate resistance to co-amoxiclav and ciprofloxacin (35% and 43%, respectively) and low resistance to piperacillin-tazobactam, ertapenem, meropenem and colistin (12%, 0%, 5% and 0%, respectively). E. coli was seen to have high resistance to ampicillin (79%), but low resistance to co-amoxiclav (4%), ciprofloxacin (9%), piperacillin-tazobactam (0%), ertapenem (0%), meropenem (4%) and colistin (0%). CONCLUSION: This study demonstrates the prevalence of Gram-negative organisms in an SA government hospital ICU. It also demonstrates the presence of resistance mechanisms in the organisms cultured for almost all available classes of antibiotics, albeit some at low levels. The development of multi- and pan-resistant pathogenic organisms is both an SA and worldwide problem. In particular, the threat posed by resistant Gram-negative bacteria is likely to manifest itself in ICUs where septic patients unresponsive to standard antimicrobial regimens will inevitably end up. Frequent assessment of resistance patterns and appropriately designed empirical treatment protocols must remain a priority for all critical care departments.