An interesting paper this month, from Brazil, examines the recovery of coagulase negative staphylococci (CNS) from clinical wastes, and the antibiotic susceptibility patterns of the isolates found there.

The authors found antibiotic resistant CNS in those wastes, and assume that this provides evidence for spread  of antibiotic resistant bacteria throughout the hospital environment and beyond, including sanitary landfill.

Nascimento TC, Da Silva VL, Ferreira-Machado AB, Diniz CG. Potential spread of multidrug-resistant coagulase-negative staphylococci through healthcare waste. J Infect Dev Ctries. 2015 Jan 15;9(1):29-34

The proposal is well put, but surely misguided. The recovery of antibiotic resistant bacteria from clinical wastes may represent those arising from patients or staff. These strains are now ubiquitous in the built environment and human microbiome so their isolation from these wastes would not be surprising. But identical strains might be found anywhere in the hospital environment, in locations unconnected with healthcare wastes. And strains found outside the hospital too, perhaps among hospital staff and ex-patients who take these strains to their home environment.

One might consider, as these authors have done, that the deposition of these wastes into sanitary landfill is a further risk. But we know that bacteria decline in numbers rapidly after deposit. Had the authors examined also more general wastes of trade or domestic origin they might have found similar stains. Would that also be a risk?

Proposing that the strains originate in waste is implausible. Proposing also that there may be some risk associated with these organisms is similarly implausible, as was the allusion to the role of healthcare waste recovered pathogens from waste in the small UK study

Tudor TL., Woolridge AC, Phillips CA, Holliday M, Laird K, Bannister S, Edgar J, Rushbrook P. Evaluating the link between the management of clinical waste in the National Health Service (NHS) and the risk of the spread of infections: A case study of three hospitals in England.  Int J Hyg Environ Health. 2010 Nov;213(6):432-6

To isolate potential pathogens or antibiotic resistant bacterial strains in healthcare waste and propose some means of spread or contribution to infection transmission is hugely flawed and little more that a scare story. Until some reliable mechanism for spread is identified no deductions of this kind can be accepted and really should have been moderated by competent refereeing prior to publication.

Both papers should be read with considerable care.