Proti protimikrobnim učinkovinam odporna Escherichia coli v kraških vodah, na površinah in v gvanu netopirjev v slovenskih jamah

Escherichia coli, one of the primary intestinal commensal bacteria in humans and endothermic animals, is commonly considered an indicator of faecal pollution. E. coli strains were isolated from karst rivers under different hydrological conditions, from footpaths in tourist caves and from bat guano. Isolates were tested for phenotypic resistance to ampicillin, chloramphenicol, ciprofloxacin, nalidixic acid, tetracycline and trimethoprim. The highest percentage of antimicrobial resistant E. coli was found in karst waters, followed by those from surface swabs and from bat guano. Several isolates from rivers and swabs exhibited multidrug-resistant phenotype. Environmental conditions impact the populations of E. coli; a positive correlation between dissolved oxygen and E. coli counts, and a negative correlation between conductivity and E. coli concentrations have been observed for karst rivers. Malenščica (Slovenia), a drinking water resource with an extensive catchment area, contained a relative high percentage of antimicrobial-resistant E. coli strains. None of the isolates from bat guano was resistant to ampicillin, chloramphenicol, and tetracycline. Future monitoring of bats should consider a regular follow-up of indicative microbial disease indicators in fresh guano. Regular cleansing of tourist footpaths in caves and disinfection barriers at the cave entrances reduce the concentration and transmission of E. coli significantly. A future, more detailed, study on characterization of additional E. coli isolates is needed to reveal their pathogeneicity, mechanisms of antibiotic resistance, mobile genetic elements, and gene transfer frequencies to other members of the karst microbiome.Bakterija Escherichia coli, eden najpomembnejših črevesnih komenzalnih mikroorganizmov pri ljudeh in drugih endotermnih živalih, velja za zanesljivega pokazatelja fekalnega onesnaženja. Sevi bakterije E. coli so bili izolirani ob različnih hidroloških razmerah iz kraških rek, s turističnih pešpoti v jamah in iz gvana netopirjev. Izolati so bili testirani na izražanje fenotipske odpornosti proti ampicilinu, kloramfenikolu, ciprofloksacinu, nalidiksični kislini, tetraciklinu in trimetoprimu. Največji odstotek E. coli, odpornih proti protimikrobnim učinkovinam, je bil v kraških vodah, sledili so brisi jamskih površin in gvano netopirjev. Pri večjem številu izolatov iz rek in brisov površin je bil izražen fenotip večkratne odpornosti proti testiranim učinkovinam. Okoljske razmere pomembno vplivajo na populacije E. coli; v kraških rekah sta bili opaženi pozitivna korelacija med raztopljenim kisikom in številom E. coli ter negativna korelacija med prevodnostjo in koncentracijo E. coli. Malenščica, vir pitne vode z velikim prispevnim območjem, je imela razmeroma velik delež sevov E. coli, odpornih proti protimikrobnim učinkovinam. Nobeden izmed izolatov iz gvana netopirjev ni bil odporen proti ampicilinu, kloramfenikolu ali tetraciklinu. Za prihodnji monitoring netopirjev bi bilo smiselno razmisliti o rednem spremljanju prisotnosti mikrobnih bolezenskih indikatorjev v svežem gvanu. Redno čiščenje turističnih pešpoti v jamah in dezinfekcijska bariera ob vhodu pomembno zmanjšata številčnost in prenos E. coli. V prihodnosti bodo potrebne še nadaljnje in podrobnejše karakterizacije večjega števila izolatov E. coli za razumevanje njihove patogenosti, mehanizmov odpornosti proti antibiotikom, mobilnih genetskih elementov in frekvenc genskega prenosa na druge organizme v kraškem mikrobiomu

Two Tales of Prokaryotic Genomic Diversity: Escherichia coli and Halophiles

Jedna je od općenitih značajki prokariota velika raznolikost genoma, na što utječu mutacije, horizontalni prijenos gena, prisutnost bakteriocina i bakterijskih virusa. Iznimna se genomska raznolikost razvila kao posljedica izlaganja mikroorganizama stresu i njihove prilagodbe različitim uvjetima okoliša. U radu su predstavljena dva primjera raznolikosti prokariota: genetska varijabilnost jedinki vrste Escherichia coli i raznolikost mikroorganizama prisutnih u slanim staništima, praćena raspravom o zdravstvenim problemima uzrokovanim unosom kontaminirane hrane i mogućnosti primjene mikroorganizama u biotehnologiji.Prokaryotes are generally characterized by vast genomic diversity that has been shaped by mutations, horizontal gene transfer, bacteriocins and phage predation. Enormous genetic diversity has developed as a result of stresses imposed in harsh environments and the ability of microorganisms to adapt. Two examples of prokaryotic diversity are presented: on intraspecies level, exemplified by Escherichia coli, and the diversity of the hypersaline environment, with the discussion of food-related health issues and biotechnological potential

QAC resistance genes in ESBL-producing E. coli isolated from patients with lower respiratory tract infections in the Central Slovenia region—a 21-year survey

Biocidal products prevent the spread of pathogenic microorganisms, including extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC), which is one of the most alarming health problems worldwide. Quaternary ammonium compounds (QACs) are surface-active agents that interact with the cytoplasmic membrane and are widely used in hospitals and food processing environments. A collection of 577 ESBL-EC, isolated from lower respiratory tract (LRT) samples, was screened for QAC resistance genes oqxAoqxBqacE∆1qacEqacF/H/IqacGsugE (p)emrEmdfAsugE (c)ydgEydgFand for class 1, 2, and 3 integrons. The prevalence of chromosome-encoded genes ranged from 77 to 100%, while the prevalence of QAC resistance genes encoded on mobile genetic elements (MGEs) was relatively low (0–0.9%), with the exception of qacE∆1 (54.6%). PCR screening detected the presence of class 1 integrons in 36.3% (n = 210) of isolates, which were positively correlated with qacE∆1. More correlations between QAC resistance genes, integrons, sequence type group ST131, and β-lactamase genes were presented. The results of our study confirm the presence of QAC resistance genes and also class 1 integrons commonly found in multidrug-resistant clinical isolates and highlight the potential role of QAC resistance genes in the selection of ESBL-producing E. coli in hospitals

Screening the cultivable cave microbial mats for the production of antimicrobial compounds and antibiotic resistance

The current work extends the phenotypic characterization of a bacterial culture collection obtained from white, yellow, grey or pink microbial cave wall colonies that are common in the caves of Slovenian Karst. We have determined antibiotic resistance to 22 natural and synthetic antibiotics in 69 isolates from the microbial mats. Thirty-eight isolates (52%) were resistant to 1-5 antibiotics; another 27 isolates (37%) were resistant to 6-10 antibiotics; and 7 isolates (0.1%) were resistant to 11-17 antibiotics. We screened for production of antimicrobial compounds by growing cave isolates on five different media and overlaying individual cultures with ten Gram-positive and Gram negative multidrug resistant isolates. Out of 78 isolates tested, 15.3% showed antimicrobial activity against Escherichia coli DH5, 15.3% against extended-spectrum β-lactamase producing Escherichia coli, 3.8% against Salmonella enterica serovar Typhimurium TL747, 9% against Klebsiella pneumoniae ATCC BAA-1706, 9% against carbapenem-resistant Klebsiella pneumoniae ATCC BAA-1705, 7.7% against Bacillus cereus, 20.5% against Bacillus subtilis, 9% against Listeria monocytogenes, 19.2% against methicillin-resistant Staphylococcus aureus, and 20.5% against methicillin-resistant Staphylococcus pseudointermedius. Results showed the potential of cave microbes to suppress the growth of multi-resistant pathogens, and, a relatively high resistance to antibiotics

Emergence of the Quinolone Resistance-Mediating Gene aac(6′)-Ib-cr in Extended-Spectrum-β-Lactamase-Producing Klebsiella Isolates Collected in Slovenia between 2000 and 2005▿

Seventy-four nonrepetitive uropathogenic fluoroquinolone-resistant or -intermediate extended-spectrum-β-lactamase-producing Klebsiella isolates from Slovenia were screened for the presence of plasmid-mediated quinolone resistance genes. None of the known qnr genes were detected. The aac(6′)-Ib-cr allele was detected on plasmids from 25 transconjugants for which the ciprofloxacin MIC was higher than for the recipient Escherichia coli strain

Two Tales of Prokaryotic Genomic Diversity: Escherichia coli and Halophiles

Prokaryotes are generally characterized by vast genomic diversity that has been shaped by mutations, horizontal gene transfer, bacteriocins and phage predation. Enormous genetic diversity has developed as a result of stresses imposed in harsh environments and the ability of microorganisms to adapt. Two examples of prokaryotic diversity are presented: on intraspecies level, exemplified by Escherichia coli, and the diversity of the hypersaline environment, with the discussion of food-related health issues and biotechnological potential