Drug resistance in airborne bacteria isolated from waste management and wastewater treatment plants in Olsztyn

Abstract

Wastewater treatment plants (WWTPs) and municipal waste management plants (MWMPs) emit bioaerosols containing potentially pathogenic biological components which post a threat for human health. Microbiological monitoring supports evaluations of the antibiotic resistance (AR) of airborne microorganisms and the relevant health risks. The aim of this study was to analyze the microbiological quality of air sampled in a WWTP and MWMP in Olsztyn based on total bacterial counts, the presence of bacteria resistant to three antibiotic classes (beta-lactams, tetracyclines and chloramphenicol) and genes encoding resistance to these antibiotics (blaTEM, blaSHV, blaCMY-2, blaAmpC, tet(M), tet(A), tet(X), tet(B), cmlA, floR, fexA, fexB and catA1 ). Bacterial counts were higher in air samples collected from the MWMP (~104 CFU/m3) than from the WWTP (101–103 CFU/m3). A similar trend was noted in the counts of antibiotic resistant bacteria (ARB). The abundance of ARB did not exceed 1.7 x 102 CFU/m3 in WWTP samples, but was higher at up to 4.2 x 103 CFU/m3 in MWMP samples. Bacteria resistant to doxycycline were least prevalent in the analyzed ARB. In the group of 49 tested bacterial strains, 44 harbored at least one of the analyzed antibiotic resistance genes (ARGs). A comparison of ARGs in all bacterial strains isolated from WWTP and MWMP air samples revealed the highest diversity and prevalence of ARGs in the samples collected in the mechanical segment of the waste processing line in MWMP and the biological segment of the wastewater processing line in WWTP. The results of this study point to high microbiological contamination of air in MWMPs and WWTPs which are reservoirs of ARB and ARGs and potential sources of AR.

The effects of season and processing technology on the abundance of antibiotic resistance genes in air samples from municipal wastewater treatment and waste management plants

“…The copy numbers of ARGs and the 16S rRNA gene were considerably higher than those reported by Gao et al [23] in a composting plant even though both the analyzed WMP and the cited composting plant processed waste in biological reactors where significant amounts of heat are generated. In a previous study conducted in the same WMP, a similar group of predominant ARGs was identified in the air in MP and BP units [14]. The observed increase in the copy numbers of tet(A), tet(B), tet(M), bla AMP-C , bla TEM , floR genes, and the 16S rRNA gene in spring could be attributed to a higher volume of managed waste.…”

“…In a preliminary analysis, the presence of four tetracycline resistance genes (tet(A), tet(B), tet(M), tet(X)), 10 beta--lactam resistance genes (bla TEM , bla SHV , bla OXA , bla CTX-M , bla CTX-M-1 , bla CTX-2 , bla CTX-M-9 , bla VEB , bla CMY , bla AMP-C ), four chloramphenicol resistance genes (floR, cmlA, fexA, fexB) and the 16S rRNA gene was determined by PCR. All primers had been previously validated for primer sequences, amplicon sizes, and annealing temperatures (the references for each sequence and detailed information on PCR conditions are presented in previous studies by Osińska et al [13] and Potorski et al [14]).…”

Gaseous emissions from wastewater facilities

“…The microbiological quality of air from a WRRF and municipal waste management (MWMP) based on total bacterial counts, presence of antibiotic-resistant bacteria, and genes-encoding resistance was assessed (Potorski, Koniuszewska, Czatzkowska, & Harnisz, 2019). In general, bacterial counts were higher in air samples from the MWMP (~10 4 CFU/m 3 ) compared to the WRRF (10-10 3 CFU/m 3 ) and the antibiotic resistance genes were most diverse in the biological area of the WRRF and in the mechanical segment of the MWMP.…”