Antimicrobial resistance and virulence determinants in coagulase-negative staphylococci isolated mainly from preterm neonates

Abstract

Coagulase-negative staphylococci (CoNS) are the most common isolates from blood culture in neonates resulting in high mortality and morbidity. This study investigated CoNS obtained from blood cultures of neonates for antibiotic resistance and virulence factors, and possible association with inflammatory response (C-reactive protein). A total of 93 CoNS isolates were collected from 76 blood cultures of neonates at the Maternity hospital in Kuwait in a six-month period and investigated for susceptibility to antibiotics, carriage of staphylococcal cassette chromosome mec (SCC mec ), and virulence-associated genes. The 93 CoNS isolates consisted of S . epidermidis (76; 81.7%), S . capitis (12; 12.9%), S . hominis (2; 2.1%), S . warneri (2; 2.1%) and S . haemolyticus (1; 1.0%). Eighty-six (92.4%) of the isolates were resistant to cefoxitin (MR-CoNS) while 49 (52.7%) expressed multi-antibiotic resistance. The methicillin-resistant isolates (MR-CoNS) carried SCC mec III, SCC mec IVa and four combinations of SCC mec types including SCC mec types I+IVa (one S . warneri and 25 S . epidermidis isolates), types I+III (one S . epidermidis isolate), types III+IVa (six S . epidermidis isolates) and types I+III+IVa (one S . epidermidis isolate). The most common virulence-related genes were icaC , seb , arc detected in 69.7%, 60.5%, 40.8% of the isolates respectively. Two isolates were positive for tst1 . No association between C-reactive protein and antibiotic resistance or virulence factors was established. This study revealed that S . epidermidis carrying different SCC mec genetic elements, was the dominant CoNS species isolated from neonatal blood cultures with 90.3% and 36.6% of the isolates positive for genes for biofilm and ACME production respectively.

Coagulase-Negative Staphylococci Clones Are Widely Distributed in the Hospital and Community

“…A single clone that has been circulating from 2009 to 2012 might be associated with an outbreak of S. capitis involving patients with a positive blood culture and a wound infection. Staphylococcus capitis is not a common nosocomial pathogen and is rarely found in the microbiota of tested patients [ 43 ]. Nevertheless, this species is endemic in some neonatal units and has been associated with bloodstream infections [ 44 ].…”

Inanimate Surfaces and Air Contamination with Multidrug Resistant Species of Staphylococcus in the Neonatal Intensive Care Unit Environment

“…In our study, more than half of the isolates were MDR, as has been observed in other studies carried out in Brazil, Colombia, and Kuwait. Those studies reported MDR S. epidermidis on “high-touch” surfaces, in NICU environmental air, and in clinical samples (52.7%, 33.9%, and 61.8%, respectively) [ 28 , 29 , 30 ]. Our study revealed the presence of S. epidermidis MDR in much higher percentages (81%), 72.7% of inanimate surfaces, 68.8% of air, and 100% of clinical isolates, which alerts us to the need for urgent measures to minimize the risk of proliferation of these microorganisms in the NICU.…”

Look Who’s Talking: Host and Pathogen Drivers of Staphylococcus epidermidis Virulence in Neonatal Sepsis

“…Among S. epidermidis isolates from neonatal blood, the vast majority (85–90%) are capable of producing biofilm [ 161 , 162 ]. However, the rate of biofilm production and the presence of icaADB and altE in S. epidermidis isolates from neonatal bloodstream infection (BSI) was comparable to commensal S. epidermidis isolates from neonatal nares [ 149 ].…”