Nasopharyngeal Carriage of Methicillin-Resistant Staphylococcus aureus (MRSA) among Sickle Cell Disease (SCD) Children in the Pneumococcal Conjugate Vaccine Era

Abstract

The aim of this cross-sectional study was to investigate Staphylococcus aureus nasopharyngeal carriage epidemiology in relation to other nasopharyngeal bacterial colonizers among sickle cell disease (SCD) children about five years into pneumococcal conjugate vaccine 13 (PCV-13) introduction in Ghana. The study involved bacteriological culture of nasopharyngeal swabs obtained from 202 SCD children recruited from the Princess Marie Louise Children’s Hospital. S. aureus isolates were identified using standard methods and subjected to antimicrobial susceptibility testing using the Kirby-Bauer disc diffusion method. Cefoxitin-resistant S. aureus isolates were screened for carriage of the mecA, pvl, and tsst-1 genes using multiplex polymerase chain reaction. The carriage prevalence of S. aureus was 57.9% (n = 117), and that of methicillin-resistant S. aureus (MRSA) was 3.5% (n = 7). Carriage of the mecA, pvl, and tsst-1 genes were respectively demonstrated in 20.0% (n = 7), 85.7% (n = 30), and 11.4% (n = 4) of the cefoxitin-resistant S. aureus isolates. PCV-13 vaccination (OR = 0.356, p = 0.004) and colonization with coagulase-negative staphylococci (CoNS) (OR = 0.044, p < 0.0001) each protected against S. aureus carriage. However, none of these and other features of the participants emerged as a determinant of MRSA carriage. The following antimicrobial resistance rates were observed in MRSA compared to methicillin-sensitive S. aureus: clindamycin (28.6% vs. 4.3%), erythromycin (42.9% vs. 19.1%), tetracycline (100% vs. 42.6%), teicoplanin (14.3% vs. 2.6%), penicillin (100% vs. 99.1%), amoxiclav (28.6% vs. 3.5%), linezolid (14.3% vs. 0.0%), ciprofloxacin (42.9% vs. 13.9%), and gentamicin (42.9% vs. 13.0%). The proportion of S. aureus isolates that were multidrug resistant was 37.7% (n = 46). It is concluded that S. aureus was the predominant colonizer of the nasopharynx of the SCD children, warranting the continuous monitoring of this risk group for invasive S. aureus infections.

Methicillin-Resistant Staphylococcus aureus (MRSA) Infection of Diabetic Foot Ulcers at a Tertiary Care Hospital in Accra, Ghana

“…The highest proportion of S. aureus resistance was recorded against penicillin (100%). Previous studies in the country have also reported similar rates for the organism [ 30 , 53 , 54 , 56 , 57 , 58 ], and this may be due to the wide usage of the antibiotic. These studies additionally recorded similar antimicrobial resistance rates for the other antimicrobials investigated [ 30 , 53 , 54 , 56 , 57 , 58 ].…”

“…Previous studies in the country have also reported similar rates for the organism [ 30 , 53 , 54 , 56 , 57 , 58 ], and this may be due to the wide usage of the antibiotic. These studies additionally recorded similar antimicrobial resistance rates for the other antimicrobials investigated [ 30 , 53 , 54 , 56 , 57 , 58 ]. Of particular interest is the high resistance displayed against cotrimoxazole in the current study, given its usage in prophylaxis.…”

“…Moreover, that MRSA prevalence was 6% and accounted for 31.6% of these S. aureus isolates is a cause for concern, given the high clinical significance of the pathogen. It is noted, though, that this prevalence is below the 15% to 30% prevalence usually attributed to MRSA in DFUs [ 52 ] and may be a reflection of the low MRSA prevalence in the country [ 30 , 53 , 54 , 55 , 56 , 57 , 58 ].…”

Nasopharyngeal Carriage and Antibiogram of Pneumococcal and Other Bacterial Pathogens from Children with Sickle Cell Disease in Tanzania

“…Several studies conducted post PCV-13 vaccine rollout have also reported a higher prevalence of S. aureus nasopharyngeal colonization in relation to S. pneumoniae among children with SCD. 27,28 Therefore, the significantly higher carriage of S. aureus relative to S. pneumoniae among the participants of our study, as well as the presence of the other nasopharyngeal colonizers in low numbers, suggest the possible modification of the nasopharyngeal microbiota which can be a result of the use of pneumococcal prophylaxis in children with SCD. 29 This raises legitimate concerns, as S. aureus, although a commensal,…”

“…32,33 The prevalence of S. aureus within this study population was lower than reported in similar studies conducted in Ghana and Brazil where higher nasopharyngeal prevalence of 57.9% and 44.8%, respectively, have been documented. 27,28 The differences could be due to the nature of the study population, pneumococcal prophylaxis uses between the two populations, and the antimicrobial resistance pattern differences.…”