Frequency and Antimicrobial Susceptibility of Multidrug-resistant Klebsiella pneumoniae Isolated From Wound Samples in Isfahan, Iran

Klebsiella pneumoniae is a gram-negative, aerobic, nonmotile bacilli and is a common cause of a wide range of infections in humans and animals. In addition, it is one of the most prevalent enteric bacteria responsible for up to 10% of all nosocomial infections and is also involved in pneumonia and urinary tract infections causing severe morbidity and mortality (1). A recent report is also available regarding the highly invasive K. pneumoniae that causes primary liver abscesses in humans (2). These invasive, abscess forming strains of K. pneumoniae are associated with the so-called hypermucoviscosity (HMV) phenotype, which is a bacterial colony trait identified by a positive string test. The HMV phenotype is found in K. pneumoniae expressing either the capsular serotypes K1 or K2. The K1 serotypes of K. pneumoniae have 2 potentially important genes of rmpA and magA. The first one is a transcriptional activator of colanic acid biosynthesis and the second one encodes a 43-kD outer membrane protein (3,). Further, the serotype capsules of K1 and K2 can cause intense diseases and based on the studies on these serotypes, magA and rmpA genes, related to HMV “in charge of the positive synthesis of outsidecapsule polysaccharide” are both useful tools in knowing such serotypes (4,5). Most K. pneumoniae isolates have a chromosomally encoded SHV-1 β-lactamase (6). Since 1983, plasmid-encoded extended-spectrum β-lactamases (ESBLs) derived from the TEM and SHV families have been extensively reported in some Gram-positive bacilli such as Staphylococcus aureus and Enterobacteriaceae, especially in Klebsiella spp. (7). Furthermore, the emergence and spread of multidrug-resistant K. Avicenna Journal of Clinical Microbiology and Infection