Retrospective Study of an Outbreak in a Kuwaiti Hospital of Multidrug-Resistant Klebsiella pneumoniae Possessing the New SHV-112 Extended-Spectrum Beta-Lactamase

Patients infected with bacteria producing extended-spectrum beta-lactamases (ESBL) are at higher risk of mortality and morbidity. Several mutations in genes encoding SHV, TEM and CTX-M beta-lactamases have been associated with ESBL activity. This paper describes a new SHV mutation in ESBL-producing strains of Klebsiella pneumoniae isolated in Kuwait. The study included 13 K. penumoniae strains isolated from patients admitted to the Amiri hospital of Kuwait. The production of ESBL in all strains was confirmed by Vitek system and E-test. All the ESBL genes were amplified by PCR and examined by DNA sequencing. All these ESBL-positive isolates were resistant to ceftazidime and cefotaxime. DNA sequencing revealed an A815G point mutation in the bla(SHV) gene causing an asparagine (AAT) to aspartic add (GAT) mutation at position 253 of the enzyme. This new mutation was assigned the unique number SHV-112, and the GeneBank accession number EU477409. This study reports a new mutation in the SHV gene in K. pneumoniae with ESBL capability. There could be other mutations still to be found in ESBL genes of K. pneumoniae in Kuwait and probably in other Middle Eastern countries, and researchers in the region should make use of molecular techniques to look for more novel mutations in ESBL-producing strains of K. pneumoniae.