Second, we found that patients having a SAPS II at admission >43 and colonization with ESBL-producing Enterobacter or K. pneumoniae species were at higher risk of developing ESBL-PE pneumonia, while having received a combination of aminopenicillin and beta-lactamase inhibitor favoured another aetiology, mostly non-fermenting gram-negative bacilli infection. This evidence concerns the gene LACTB and pneumonia.