Nosocomial infection caused by class 1 integron-carrying Staphylococcus aureus in a hospital in South China

Abstract

Staphylococcus aureus isolates (n = 30) from the environment or from surgical patients in a hospital in Guangzhou, China were investigated for the presence of class 1 integrons. The class 1 integrase (intI1) gene and its 3' conserved segment were detected by PCR. IntI1-positive isolates were further analysed for the presence of resistance gene cassettes using specific primers, intI1-K and In-B. All isolates were also subjected to multilocus sequence typing (MLST) and random amplified polymorphic DNA (RAPD)-PCR analysis. Sixteen (53%) clinical and environmental isolates were positive for the class 1 integrase gene and were also found to possess the aadA2 gene. The 30 isolates were classified into six distinct genotypes by RAPD-PCR analysis: type A (n = 2); type B (n = 2); type C (n = 3); type D (n = 7); type E (n = 8); and type F (n = 8). All isolates belonged to the same sequence type (ST239) by MLST. These results indicated transmission of S. aureus between the environment and patients, as well as the probability of nosocomial infection.

A Study on Class I Integrons and Antimicrobial Resistance among Clinical Staphylococci Isolates from a Turkish Hospital

“…They showed the presence of class 1 integrons in 30 MRCoNS strains. Gene cassettes such as dfrA12-orfF-aadA2 and dfrA17-aadA5, which had been already shown in gram-negative strains, were detected in the class 1 integron positive strains [10][11][12]. In our study, we could not detect the existence of class 1 integron in clinical MRS isolates.…”

“…The class 1 integron positive strains included MRSA, MRCoNS and E. faecalis. In another study from China, Xu et al investigated the presence of class 1 integrons in nosocomial MRSA strains [11]. They detected class 1 integrons in 53% of the clinical strains.…”

“…They showed class 1 integron positive MRSA had only additional resistance to spectinomycin and streptomycin which are not commonly used for antibacterial treatment today [13]. In a previous study, Xu et al stated that indiscriminate use of existing antibiotics resulted in antibiotic selective pressure and was reflected by the prevalence of integrons [11]. Clinical use of spectinomycin and streptomycin which causes so much selective pressure is questionable.…”

“…While the role of class 1 integrons is well documented in the spread of antibiotic resistance genes in gramnegative bacteria, there is less information about the prevalence of class 1 integrons in gram-positive bacteria [5,10]. The presence of class 1 integrons in clinical staphylococcal isolates has been only shown in the studies from China [10][11][12][13][14]. In the literature, there is no other study investigating the presence of integrons in clinical staphylococcal isolates.…”

Role of integrons in antimicrobial resistance: A review

“…In the series studies of systematic integrons investigation conducted during 2001 to 2006 (Xu et al, 2007(Xu et al, , 2008a(Xu et al, , b, 2011b, 122 out of 262 Staphylococcus strains were positive for class 1 integrase (intI1), with none of class 2 and 3 integrase gene obtained. Of these IntI1-positive strains, 115 (94.3%, 115/122) strains contained the typical 3'CS of qacEΔ1-sul1, and 4 different (Xu et al, 2011c).…”