<p>Antibiotic Resistance and <em>mecA</em> Gene Characterization of Coagulase-negative <em>Staphylococci</em> Isolated from Clinical Samples in Nepal</p>

Abstract

Background Coagulase-negative Staphylococci (CoNS) are a significant cause of hospital-acquired and foreign-body-related infections. We conducted this research to assess methicillin susceptibility of CoNS by disc diffusion, agar dilution, and polymerase chain reaction (PCR) methods and to assess the antimicrobial susceptibility pattern. Methods We received 123 CoNS isolates from different specimens including blood, endotracheal tube, and central venous catheter. We performed sample processing, identification, and characterization following standard guidelines. Antimicrobial susceptibility was tested based on clinical and laboratory standards institute guidelines. We detected methicillin-resistant coagulase-negative staphylococci (MRCoNS) through mecA gene, disc diffusion method, and agar dilution method and compared the accuracy with PCR as reference. Results We detected eight species of CoNS with Staphylococcus epidermidis as the most common. Most of the samples were received from the intensive care unit and blood was the dominant specimen followed by endotracheal-tube aspirate. Seventy-one percentage of isolates were methicillin-resistant by PCR method; disc diffusion and agar dilution method detected methicillin resistance with an accuracy of 96.7% and 98.3%, respectively. Antimicrobial susceptibility revealed an association between the different origins of samples, and also among the types of sample. Similarly, a comparison of the degree of resistance of antimicrobial agents between mecA gene positive and negative isolates showed significant differences. Vancomycin, linezolid, and teicoplanin are still effective for treating MRCoNS. Conclusion CoNS are a crucial cause of human infections especially in an intensive care unit setup where the use of devices is common. Disc diffusion and agar dilution are reliable for the detection of MRCoNS. The degree of antimicrobial resistance is much higher in organisms obtained from intensive care unit and foreign-body-related infections.

Phenotypic and genotypic characterization of biofilm producing clinical coagulase negative staphylococci from Nepal and their antibiotic susceptibility pattern

“…However, the study also demonstrated majority of isolates being susceptible to chloramphenicol (91.1%) and tetracycline (87.4%). Such high frequency of susceptibility pattern of chloramphenicol is consistent with the previous study by [ 24 , 33 , 36 , 37 ], but their study showed lower susceptibility in case of erythromycin and penicillin. Indeed, similar susceptibility profile for all CNS strains was found as that of S. epidermidis strains.…”

“…S. saprophyticus along with blood and wound/pus was also isolated from urine. The high number of S. saprophyticus in urine is consistent with the previous studies [ 24 , 35 ] may be due to its adhering capacity to wall of urinary tract. Importantly, all CNS species were isolated from different medical devices indicating their ability to cause device associated infections.…”

“…Among 214 CNS, S. epidermidis was the most common isolate accounting for more than half (57.4%) of total numbers (n = 123 ) followed by S. saprophyticus (n = 40, 18.6%), S. haemolyticus (n = 24, 11.2%), S. hominis (n = 15, 7%) and S. capitis (n = 12, 5.6%) (Table 1 ). Previous studies have also reported S. epidermidis as the most common isolates among CNS [ 24 , 32 – 34 ]. While S. epidermidis was isolated form all clinical samples, it was more commonly isolated from blood, wound/pus.…”

Methicillin-resistant Staphylococcus aureus in Nepal

“… 1 , 2 Methicillin resistance in S. aureus is mediated through an altered protein called low-affinity penicillin-binding protein (PBP2a) which is encoded by the mecA gene which is present in a chromosomal mobile genetic element called Staphylococcal cassette chromosome. 3 - 5 The most recent data regarding MRSA incidence obtained from WHO reported values exceeding 20% in all WHO regions, and even 80% in some countries. 6 MRSA is frequently resistant to most of the commonly used antimicrobial agents including aminoglycosides, macrolides, chloramphenicol, tetracycline, and fluoroquinolones.…”

Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in Hospitalized Patients in Eastern Heilongjiang Province, China

“…The principle drug resistance gene in MRSA strains is mecA, which is also known to exist in coagulase-negative Staphylococci (CoNS). 8 In addition, MRSA carrying the mecC gene has also been reported. 9 The common colonization sites of MRSA are the nasal vestibule, pharynx, gastrointestinal tract, and axilla.…”