Slime layer formation and the prevalence of mecA and aap genes in Staphylococcus epidermidis isolates

Abstract

Introduction: Staphylococcus epidermidis strains are frequently associated with catheter-related infection, acute bacteremia, and hospitalacquired infection. Some isolates produce an extracellular matrix called slime that may make them more resistant to antibiotics. The aim of this study was to determine antimicrobial resistance patterns, the prevalence of slime production, and the distribution of genes (mecA and aap, respectively) associated with these phenotypes in S. epidermidis nasal isolates from health-care personnel. Methodology: A descriptive cross-sectional study was performed on 163 nasal swabs from health-care staff (one swab per subject). S. epidermidis isolates were tested for slime production on congo red agar and antibiotic resistance. PCR-based screening for mecA and aap genes was performed upon the extracted DNA of S. epidermidis isolates. Results: A total of 99 S. epidermidis strains were cultured from 58.9% of the study participants (n = 96). Of these strains, 34 (34.3%) isolates produced slime. A significant relation between slime production and resistance to penicillin 32(94%) , oxacillin 30(88%),, tetracycline 20(59%), erythromycin 27(79%), and clindamycin 26(77%) was found. Respectively, 95.8% and 94.8% of all isolates were PCR-positive for mecA and aap, but only 59.8% of mecA+ strains were oxacillin-resistant and 37.3% of aap+ strains were slime producers. Conclusions: The surveillance of nasal colonization with slime-forming oxacillin-resistant S. epidermidis in health-care workers might be helpful in breaking the epidemiological chain of hospital-acquired infections.

Biofilm formation and antimicrobial resistance in methicillin-resistant Staphylococcus aureus isolated from burn patients, Iran

“…MRSA isolates that were resistant to multiple antibiotics were mostly biofilm producers, so it can be concluded that the majority of MDR pathogens are likely biofilm producers or vice versa. This result is in accordance with other studies [31,32]. Most hospital-acquired MRSA are also resistant to numerous other antibiotics.…”

Comparison of Hypervariable Region (HVR) of mecA Gene in Staphylococcus aureus Isolated From Nasal Carriers and Clinical Samples

“…This is while some sensitive isolates also have mecA gene. The underlying cause of this discrepancy between phenotype and genotype can be pointed the mutations, which leads to palindrome defect in -10 region of mecA promoter (13). Moreover, it was mentioned that the clinical isolates from the ICU wards had shown the highest number of HVR types.…”

An overview of Staphylococcus epidermidis and Staphylococcus aureus with a focus on developing countries

“…Specifically, catheter-related infections are associated with increased mortality and contribute to an increased length of hospital stay and higher healthcare costs, which are problematic in limited-resource settings such as South Africa [12,13]. In three different hospitals Iran, nasal swabs were collected from 163 healthcare workers; 96 were cultured and resulted positive for S. epidermidis [14]. Similar results were reported in a study performed between 2000 and 2009 in a hospital in Kenya, where in blood samples collected from neonates, S. epidermidis accounted for 33% of the isolated strains [15].…”