Biocidal agents used for disinfection are usually not suspected to enhance cross-resistance to antibiotics. The aim of this review was therefore to evaluate the effect of 13 biocidal agents at sublethal concentrations on antibiotic resistance in Gram-negative species. A medline search was performed for each biocidal agent on antibiotic tolerance, antibiotic resistance, horizontal gene transfer, and efflux pump. In cells adapted to benzalkonium chloride a new resistance was most frequently found to ampicillin (eight species), cefotaxime (six species), and sulfamethoxazole (three species), some of them with relevance for healthcare-associated infections such as Enterobacter cloacae or Escherichia coli. With chlorhexidine a new resistance was often found to ceftazidime, sulfamethoxazole and imipenem (eight species each) as well as cefotaxime and tetracycline (seven species each). Cross-resistance to antibiotics was also found with triclosan, octenidine, sodium hypochlorite, and didecyldimethylammonium chloride. No cross-resistance to antibiotics has been described after low level exposure to ethanol, propanol, peracetic acid, polyhexanide, povidone iodine, glutaraldehyde, and hydrogen peroxide. Taking into account that some biocidal agents used in disinfectants have no health benefit (e.g., in alcohol-based hand rubs) but may cause antibiotic resistance it is obvious to prefer products without them.

The novel human coronavirus SARS-CoV-2 has become a global health concern causing severe respiratory tract infections in humans. Human-to-human transmissions have been described, probably via droplets but possibly also via contaminated hands or surfaces. In a recent review on the persistence of human and veterinary coronaviruses on inanimate surfaces it was shown that human coronaviruses such as Severe Acute Respiratory Syndrome (SARS) coronavirus, Middle East Respiratory Syndrome (MERS) coronavirus or endemic human coronaviruses (HCoV) can persist on inanimate surfaces like metal, glass or plastic for up to 9 days. Some disinfectant agents effectively reduce coronavirus infectivity within 1 minute such 62%–71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite. Other compounds such as 0.05%–0.2% benzalkonium chloride or 0.02% chlorhexidine digluconate are less effective. An effective surface disinfection may help to ensure an early containment and prevention of further viral spread.