MINIREVIEW Detection of bla SHV , bla TEM and bla CTX-M antibiotic resistance genes in randomly selected bacterial pathogens from the Steve Biko Academic Hospital Marthie M. Ehlers, Chrisna Veldsman, Eddy P. Makgotlho, Michael G. Dove, Anwar A. Hoosen & Marleen M. Kock Department of Medical Microbiology, Faculty of Health Sciences, University of Pretoria/NHLS, Pretoria, South Africa Correspondence: Marthie M. Ehlers, Department of Medical Microbiology, Faculty of Health Sciences, University of Pretoria/NHLS, Prinshof Campus, PO Box 2034, Pathology Building, Pretoria 0001, South Africa. Tel.: 127 12 319 2170; fax: 127 12 321 9456; e-mail: marthie.ehlers@up.ac.za Received 12 December 2008; revised 10 March 2009; accepted 24 March 2009. Final version published online 8 May 2009. DOI:10.1111/j.1574-695X.2009.00564.x Editor: Willem van Leeuwen Keywords extended-spectrum b-lactamases; cefotaximase; temoniera; sulfhydryl variable. Abstract Extended-spectrum b-lactamases (ESBLs) are considered to be one of the most important antibiotic resistance mechanisms. This study reported the ESBL- producing genes in 53 randomly selected clinical bacterial isolates from the Steve Biko Academic Hospital. The presence of the bla SHV , bla TEM and bla CTX-M genes was determined, and the overall prevalence of these genes detected in this study was 87% (46/53) in comparison with the literature; these results were higher when compared with 33% for Escherichia coli in Europe and 0.8% in Denmark for similar pathogens. These research findings indicated that it is crucial to routinely monitor the prevalence of these resistance genes. Introduction Extended-spectrum b-lactamases (ESBLs) were first identi- fied in the early 1980s in Germany and have since been identified worldwide (Winkokur et al., 2001; Meyer et al., 2004). The ESBL genes have been found in a number of different bacteria, including Klebsiella pneumoniae, Escher- ichia coli, Proteus mirabilis and Salmonella species (Paterson, 2000; Winkokur et al., 2001). b-Lactamase-producing bac- teria are increasingly been reported as the cause of severe infections in intensive care and surgical units (Samaha- Kfoury & Araj, 2003; Sorl ´ ozano et al., 2004). Infections associated with ESBL-producing bacteria include central venous line-related bacteraemia, cholangitis, intra-abdom- inal abscesses, peritonitis and urinary tract infections (Paterson, 2000). In hospitalized patients, ESBL producers may cause nosocomial pneumonia and meningitis (Pater- son, 2000). Mortality rates varying from 42% to 100% have been reported in patients infected with ESBL-producing bacteria (Colodner, 2005). ESBL-producing bacteria often show cross-resistance with other groups of antibiotics, such as fluoroquinolones (Co- lodner, 2005). It was indicated that 18% of ESBL-producing isolates in the United States were also ciprofloxacin resistant (Colodner, 2005). The early detection of ESBLs is therefore extremely important, because the prevalence of ESBLs is severely underestimated (Colodner, 2005). Most ESBL-producing bacteria can be divided into three groups: TEM, SHV and CTX-M types (Pitout & Laupland, 2008). Gram-negative b-lactamases are often mediated by bla SHV , bla TEM and bla CTX-M genes (Tzouvelekis et al., 2000; Monstein et al., 2007). The SHV enzymes are named after the sulfhydryl variable active site and are commonly asso- ciated with K. pneumoniae (Samaha-Kfoury & Araj, 2003). Initially, these bacteria contained a single ESBL gene, but now multiple ESBL genes are commonly present in a single strain, further complicating the process of detection (Sama- ha-Kfoury & Araj, 2003). The TEM-type ESBL are deriva- tives of TEM-1 and TEM-2, and currently, TEM-3 has been discovered, differing from TEM-2 by two amino acid FEMS Immunol Med Microbiol 56 (2009) 191–196 c  2009 Federation of European Microbiological Societies Published by Blackwell Publishing Ltd. All rights reserved IMMUNOLOGY & MEDICAL MICROBIOLOGY