Review of Clinically and Epidemiologically Relevant Coagulase-Negative Staphylococci in Africa

Abstract

Coagulase-negative staphylococci (CoNS) have engendered substantial interest in recent years as pathogenic causes of infections in both human and veterinary medicine, especially in the immunocompromised, critically ill, long-term hospitalized and in those harboring invasive medical devices such as catheters. They have been implicated in infections such as urinary tract infections, bloodstream infections, and invasive device-related infections, and are responsible for substantial economic losses in livestock production. The advancement of diagnostic techniques has increased our understanding of their molecular mechanisms of pathogenicity, even though distinguishing between innocuousness and pathogenicity is still challenging. The incidence of CoNS varied across the continent in humans and animals (mainly cattle), ranging from 6% to 68% in suspected human infections and from 3% to 61.7% in suspected animal infections, distributed across different geographic locations. Furthermore, there were varying antibiotic resistance patterns observed in CoNS isolates, with high methicillin resistance in some cases, leading to crossresistance against many antibiotics. Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus xylosus were most commonly reported in studies herein reviewed, while the enterotoxin C gene, atl E gene, ica gene, and hemolysin virulence factors were linked with enhanced pathogenicity. Advancement in identification and typing methods, including whole genome sequencing, virulence screening, and the assessment of the immune status of subjects in studies will help to thoroughly assess the true pathogenic potential of isolated CoNS species in developing countries. Careful antibiotic stewardship guidelines should be followed due to the ability of CoNS to develop multidrug resistance.

Prevalence and antimicrobial resistance of Staphylococcus species isolated from cats and dogs

“…Staphylococcus aureus is the main pathogenic species; however, other staphylococci emerged, particularly the coagulasenegative staphylococci (CoNS), causing serious opportunistic infections in human and animals (Rich, 2005). In Africa, the incidence of CoNS varied across the continent and reported approximately from 68% and 62% of suspected human and animal infections, respectively, particularly from clinical cattle and hospitalized humans (Asante et al, 2020). In Libya, methicillin-resistant S. aureus (MRSA) is the most reported and investigated nosocomial pathogens exclusively isolated from healthcare settings and human clinical sources (Ahmed et al, 2017).…”

“…Methicillin-resistant staphylococci (MRS) were isolated from household pets associated significantly with antibiotic intake and veterinary hospitalization, expressing genetic determinants and clonal lineages similar to those typically identified in humans and other animals (i.e., staphylococcal cassette chromosome and Panton-Valentine Leucocidin (pvl) gene) (van Duijkeren et al, 2005;Han et al, 2016;Rossi et al, 2017;Loncaric et al, 2019). Nevertheless, epidemiological and clinical information from Africa on healthcare-associated pathogens isolated from pet animals are very rare compared to the extensive knowledge on human and food-producing animals (Ahmed and Baptiste, 2018;Asante et al, 2020). The aim of the current study was to investigate the prevalence and antimicrobial susceptibility of Staphylococcus species isolated from healthy and clinical cats and dogs in Tripoli, Libya.…”

Multidrug-Resistant Coagulase-Negative Staphylococci Isolated from Bloodstream in the uMgungundlovu District of KwaZulu-Natal Province in South Africa: Emerging Pathogens

“…Staphylococci are classified as either coagulase-positive or coagulase-negative, depending on their ability to clot plasma that is facilitated by the enzyme coagulase [1]. Coagulase-negative staphylococci (CoNS) are the most frequent colonizers of the skin and mucous membranes and the most frequently isolated organisms in microbiology laboratories [2]. Although CoNS are mostly considered contaminants in clinical specimens, they have been implicated in clinically relevant infections, including urinary tract infections, endocarditis, bloodstream infections (including neonatal sepsis), and foreign body-related infections [2].…”

“…Coagulase-negative staphylococci (CoNS) are the most frequent colonizers of the skin and mucous membranes and the most frequently isolated organisms in microbiology laboratories [2]. Although CoNS are mostly considered contaminants in clinical specimens, they have been implicated in clinically relevant infections, including urinary tract infections, endocarditis, bloodstream infections (including neonatal sepsis), and foreign body-related infections [2]. The skin and mucous membranes of the host, which are home to an abundance of CoNS species, are significant sources of endogenous CoNS infections, facilitated by transmission through medical procedures [3].…”

“…CoNS are the most common pathogens implicated in nosocomial bloodstream infections, responsible for 30-40% of these infections [4]. A study found a CoNS prevalence of 6-68% in suspected human infections in Africa within the last decade [2]. Of the CoNS, Staphylococcus epidermidis is the most common cause of human infection, culpable for about 24-80% of these infections [3].…”