Genetic Polymorphism of agr Locus and Antibiotic Resistance of Staphylococcus aureus at two hospitals in Pakistan

Pakistan Journal of Medical Sciences Online (Impact Factor: 0.23). 03/2014; 30(1):172-6. DOI: 10.12669/pjms.301.4124
Source: PubMed


Objective: The accessory gene regulator (agr) locus in Staphylococcus aureus (S. aureus) is a global regulator of quorum sensing and controls the production of virulence factors. This study was carried out to investigate the agr specific groups both in methicillin resistant and sensitive Staphylococcus aureus (MRSA and MSSA) and their relation with antibiotic resistance.
Methods: A total of 90 clinical S. aureus isolates were studied from two tertiary care hospitals. The isolates were identified by standard biochemical tests. Methicillin resistance was confirmed by oxacillin and cefoxitin resistance. Multiplex PCR was used to determine the agr groups.
Results: MRSA prevalence was found to be 53.3%.The agr groups’ distribution in MRSA was as follows: 22 (45.8%) belonged to group I, 14 (29.1%) belonged to group III and 2 (4.1%) belonged to group II. agrIV was not detected in MRSA. For 17 isolates, the agr group was not detected.agr III isolates showed higher antibiotic resistance than agrI isolates except in case of oxacillin and linezolid.
Conclusions: Strict infection control policy and antibiotic guidelines should be adopted to control the problem of MRSA. Higher prevalence of agr I and agr III shows that they are dominant agr groups of our area.

Download full-text


Available from: Rabaab Zahra, Dec 30, 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), is a major bacterial pathogen associated with nosocomial and community-acquired S. aureus infections all over the world. A rapid detection assay for staphylococcal gene of nuc and mecA is needed. In this study, a rapid identification assay based on the loop-mediated isothermal amplification (LAMP) method was established. PCR and LAMP assays were used to detect Staphylococcus aureus and other related species for nuc and mecA. With optimization of the primers and reaction temperature, the LAMP successfully amplified the genes under isothermal conditions at 62 °C within 60 min, of which the results were identical with those of the conventional PCR methods. The detection limits of the LAMP for nuc and mecA were 1.47 and 14.7 pg/μl DNA per tube, respectively, by naked eye inspections, while the detection limits of the PCR for nuc and mecA were 14.7 pg/μl and 147 pg/μl DNA, respectively. Finally, The LAMP method was then applied to clinical blood plaque samples. The LAMP and PCR demonstrated identical results for the plaque samples with the culture assay. Together, the LAMP offers an alternative detection assay for nuc and mecA with a great advantage of the sensitivity and rapidity.
    No preview · Article · Oct 2014 · Applied Biochemistry and Biotechnology
  • [Show abstract] [Hide abstract]
    ABSTRACT: The genetic relationships in Staphylococcus aureus isolated from raw poultry obtained from various Brazilian broiler chicken processors were analyzed using repetitive extragenic palindromic-polymerase chain reaction (rep-PCR). The distribution of accessory gene regulator (agr) groups was determined, and the presence of biofilm-associated genes and phenotypic features, including biofilm formation and proteolytic, lipolytic, and β-hemolytic activities, was assessed. Isolates were grouped into three major clusters based on rep-PCR fingerprints typed with RW3A primer. The agr group I was the most common genotype identified (86.21 %), followed by groups II (10.34 %) and III (3.45 %). All strains were positive for the sasG gene; the next most frequent genes were icaA (93.1 %) and atlA (51.72 %). Twenty-six of the 29 isolates were biofilm producers. In this study, 96.55 %, 72.41 %, and 62.06 % of the isolates displayed lipolytic, β-hemolytic, and proteolytic activity, respectively. In conclusion, the rep-PCR results suggested a clonal relationship among the S. aureus isolated from raw poultry produced by different broiler chicken processors. Our results also showed that most isolates belonged to agr group I. The presence of biofilm-forming S. aureus strains in raw poultry, their ability to harbor biofilm-associated genes, and the spoilage features that they exhibit are indicative of their pathogenic potential, and may represent a serious problem in the food processing industry.
    No preview · Article · Jan 2015 · Annals of Microbiology
  • Source

    Full-text · Article · Jan 2016