Ertapenem for treatment of extended-spectrum beta-lactamase-producing and multidrug-resistant gram-negative bacteraemia

<p><b>INTRODUCTION</b>Imipenem and meropenem are treatment of choice for extended-spectrum betalactamase (ESBL)-positive gram-negative bacteraemia. They may select for carbapenemresistant Acinetobacter baumannii and Pseudomonas aeruginosa; ertapenem may not do so as it is inactive against these bacteria. Clinical efficacy of ertapenem in ESBL-producing gramnegative bacteraemia is limited.</p><p><b>MATERIALS AND METHODS</b>Retrospective study of patients with ESBL-positive gram-negative bacteraemia treated with ertapenem was undertaken.</p><p><b>RESULTS</b>Forty-seven patients with multidrug-resistant gram-negative bacteraemia (79% produced ESBL) were treated with ertapenem for a median duration of 11 days. The median age was 70 years. Septic shock occurred in 19% and mechanical ventilation was needed in 17%. Klebsiella pneumoniae comprised 53% and Escherichia coli 26%. Urinary infection accounted for 61% and hepatobiliary 15%. Favourable clinical response occurred in 96%. Attributable mortality was 4%.</p><p><b>CONCLUSION</b>Ertapenem is promising in culture-guided step-down therapy of ESBL-positive gram-negative bacteraemia.</p>

Community-associated methicillin-resistant Staphylococcus aureus: overview and local situation

<p><b>INTRODUCTION</b>Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged worldwide. In contrast to healthcare-associated MRSA (HA-MRSA), CA-MRSA isolates are usually susceptible to multiple non-beta-lactam antibiotics and cause a distinct spectrum of infections in epidemiologically disparate populations - in particular, cutaneous abscesses, necrotising fasciitis and necrotising pneumonia. They arise from a broader genetic background, and possess differing virulence genes. We aim to describe the distribution of different molecular subtypes of CA-MRSA among various regions and discuss briefly the implications of CA-MRSA from a local perspective.</p><p><b>METHODS</b>Literature review of articles on CA-MRSA, focusing mainly on reports where the genetic background of isolates had been analysed using multi-locus sequence typing (MLST). Singapore data were obtained from the local CA-MRSA database.</p><p><b>RESULTS</b>MLST analysis demonstrated the presence of epidemic subtypes of CA-MRSA within most geographic areas. In parts of the United States, community MRSA infections currently exceed those caused by their methicillin-susceptible counterparts. In Singapore, CA-MRSA infections are increasing, predominantly as a result of the spread of ST30 clones.</p><p><b>CONCLUSION</b>Available evidence suggests that the emergence of MRSA from the community is not going to be a transient phenomenon. Local guidelines for dealing with this phenomenon at both therapeutic and preventive levels are needed prior to the potential development of a situation mirroring that of meso-endemic HA-MRSA in local hospitals or CA-MRSA epidemics in parts of USA.</p>