Potential spread of multidrug-resistant coagulase-negative staphylococci through healthcare waste

Abstract

Introduction: Healthcare waste (HCW) might potentially harbor infective viable microorganisms in sanitary landfills. We investigated the antimicrobial susceptibility patterns and the occurrence of the mecA gene in coagulase-negative Staphylococcus strains (CoNS) recovered from the leachate of the HCW in an untreated sanitary landfill. Methodology: Bacterial identification was performed by physiological and molecular approaches, and minimum inhibitory concentrations (MICs) of antimicrobial drugs were determined by the agar dilution method according to CLSI guidelines. All oxacillin-resistant bacteria were screened for the mecA gene. Results: Out of 73 CoNS, seven different species were identified by 16S rDNA sequencing: Staphylococcus felis (64.4%; n = 47), Staphylococcus sciuri (26.0%; n = 19), Staphylococcus epidermidis (2.7%; n = 2), Staphylococcus warneri (2.7%; n = 2), Staphylococcus lentus (1.4%; n = 1), Staphylococcus saprophyticus (1.4%; n = 1), and Staphylococcus haemolyticus (1.4%; n = 1). Penicillin was the least effective antimicrobial (60.3% of resistance; n = 44) followed by erythromycin (39.8%; n = 29), azithromycin (28.8%; n = 21), and oxacillin (16.5%; n = 12). The most effective drug was vancomycin, for which no resistance was observed, followed by gentamicin and levofloxacin, for which only intermediate resistance was observed (22%, n = 16 and 1.4%, n = 1, respectively). Among the oxacillin-resistant strains, the mecA gene was detected in two isolates. Conclusions: Considering the high antimicrobial resistance observed, our results raise concerns about the survival of putative bacterial pathogens carrying important resistance markers in HCW and their environmental spread through untreated residues discharged in sanitary landfills.

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

“…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]. Furthermore, a study carried out in Brazil showed that 2.7% of S. epidermidis strains were isolated from hospital healthcare wastes, indicating a potential risk of spread outside the hospital setting [16].…”

Sphygmomanometers and thermometers as potential fomites of Staphylococcus haemolyticus: biofilm formation in the presence of antibiotics

“…The extent to which fomites contribute to overall rates of nosocomial infection remains unknown. However, fomites play a notable role in the transmission of Gram-positive and Gram-negative bacterial pathogens, including staphylococcal species ( Nascimento et al 2015 ).…”

“…Fomite surfaces that are transported between hospital rooms are of particular concern and have been implicated in nosocomial outbreaks caused by different genera and species, including methicillin-resistant Staphylococcus aureus (MRSA) ( Cohen et al 1997 , Nascimento et al 2015 , Zargaran et al 2015 ). Since the 1970s, only a few studies have investigated the contamination of fomites by coagulase-negative staphylococci (CoNS), predominantly Staphylococcus epidermidis ( Lowbury et al 1971 , Saito et al 2014 , Zargaran et al 2015 ).…”

Prevalencia de estafilococos resistentes a meticilina en el personal trabajador del Hospital Clínico Veterinario de la UEX

“…Por otro lado, el gen mecA se ha encontrado en especies coagulasa negativo no responsable de procesos patógenos en los que presumiblemente no debería haberse utilizado una terapia antibiótica, y pueden actuar como reservorio de la resistencia a largo plazo (Nascimento et al, 2015;Zong et al, 2011).…”