Results of two worldwide surveys into physician awareness and perceptions of extended-spectrum β-lactamases

The anti-Pseudomonas aeruginosa antibody Panobacumab is efficacious on acute pneumonia in neutropenic mice and has additive effects with meropenem

Pseudomonas aeruginosa (P. aeruginosa) infections are associated with considerable morbidity and mortality in immunocompromised patients due to antibiotic resistance. Therefore, we investigated the efficacy of the anti-P. aeruginosa serotype O11 lipopolysaccharide monoclonal antibody Panobacumab in a clinically relevant murine model of neutropenia induced by cyclophosphamide and in combination with meropenem in susceptible and meropenem resistant P. aeruginosa induced pneumonia. We observed that P. aeruginosa induced pneumonia was dramatically increased in neutropenic mice compared to immunocompetent mice. First, Panobacumab significantly reduced lung inflammation and enhanced bacterial clearance from the lung of neutropenic host. Secondly, combination of Panobacumab and meropenem had an additive effect. Third, Panobacumab retained activity on a meropenem resistant P. aeruginosa strain. In conclusion, the present data established that Panobacumab contributes to the clearance of P. aeruginosa in neutropenic hosts as well as in combination with antibiotics in immunocompetent hosts. This suggests beneficial effects of co-treatment even in immunocompromised individuals, suffering most of the morbidity and mortality of P. aeruginosa infections.

Extended-spectrum beta-lactamases

The first beta-lactamase was identified in an isolate of Escherichia coli in 1940. To date, there are >130 TEM-type and >50 sulfhydryl variable (SHV)-type beta-lactamases, mainly in E. coli, Klebsiella pneumoniae, and Proteus mirabilis but also in other members of the Enterobacteriaceae family and in some nonenteric organisms, such as Acinetobacter species. The incidence of expanded-spectrum beta-lactamases (ESBLs) varies, depending on which area of the globe the isolates originate from. ESBLs render the oxyimino-cephalosporins ineffective, and ESBL-producing organisms frequently also possess resistance factors to other classes of antibiotics, such as aminoglycosides and fluoroquinolones, and possibly also piperacillin-tazobactam and cefepime. These results suggest that microbiology laboratories should routinely test for the presence of these strains among their isolates and that the antibiotics of choice for infections believed to be caused by these types of organisms are the carbapenems.

Prevalence and antimicrobial susceptibility data for extended-spectrum β-lactamase– and AmpC-producing Enterobacteriaceae from the MYSTIC Program in Europe and the United States (1997–2004)

This article presents prevalence and susceptibility data from the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program in Europe (1997-2004) and the United States (1999-2004) for Enterobacteriaceae producing extended-spectrum beta-lactamase (ESBL) and/or AmpC beta-lactamases. For ESBL-producing isolates, the prevalence of Escherichia coli and Klebsiella spp. in Europe and Enterobacter spp. in the United States increased over time. For AmpC-producing isolates, the prevalence of Enterobacter spp. and Citrobacter spp. decreased over time in Europe and the United States, respectively. Compared with other antimicrobial agents, meropenem and imipenem had greatest activity against ESBL-producing E. coli and Klebsiella spp. in both Europe (96.9-100.0%) and the United States (100.0%). Such activity was also found for AmpC-producing Enterobacteriaceae in Europe (50.0-100.0%), and Enterobacter spp. and Citrobacter spp. from the United States (100.0% for both). The continued efficacy of carbapenems such as meropenem confirms that these remain first-line agents for treatment of nosocomial infections caused by Enterobacteriaceae-producing ESBL or AmpC beta-lactamases.