The occurrence of antibiotic-resistant bacteria on the clothes of nursery teachers in daycare centres.

AIMS: Childcare facilities act as microenvironments that facilitate and promote the selection, spread and transmission of antibiotic-resistant micro-organisms in the community. We focused on the study of antimicrobial resistance and genetic predispositions for ß-lactamase production in bacterial isolates from nursery teachers' clothing. METHODS AND RESULTS: Antimicrobial resistance of bacterial strains belonging to Enterobacteriaceae, Enterococcus, Staphylococcus spp., Pseudomonas spp. and Bacillus spp. isolated from 80 samples of nursery teachers' clothing was determined. The selected ESßL genes were found in 30 (44.1%) of 68 strains examined. The CTX-M type ESßL determinants were detected in 15.4%, 71.5% and 42.5% of the Enterobacteriaceae, Pseudomonas and Bacillus isolates, respectively. The OXA-type coding genes were detected only in strains of the genera Pseudomonas (57.1%) and Bacillus (48.6%). Thus, most B. cereus strains were sensitive to the recommended antibiotics used to treat infections caused by these bacteria. Methicillin resistance was phenotypically confirmed in 27 (14.6%) of 185 staphylococcal isolates. Four isolates (2.2%) were identified as MRSA. Vancomycin resistance was not observed in any of the staphylococcal and enterococci strains. CONCLUSIONS: This study has shown that potential pathogens have been isolated from the clothing of nursery teachers, posing a risk of transmission to children. These clothes should be maintained and properly laundered to avoid cross-contamination and the spread of multidrug-resistant (MDR) bacteria in childcare centres. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides insight into the route of transmission of MDR micro-organisms through the clothing of nursery teachers, to which greater importance should be given in the future. Proper procedures for the cleaning and use of clothing in daycare centres should be clarified and standardized.

Genetic diversity and the presence of circular plasmids in Bacillus cereus isolates of clinical and environmental origin.

The diversity of 61 Bacillus cereus strains isolated from different clinical specimens, food including raw milk and milk products, and water was evaluated. PFGE analysis could discriminate 61 distinct pulsotypes with similarity levels from 25 to 82%, which were divided into 13 clonal complexes. The similarity between clonal complexes was at least 40%. Clinical strains were divided into 10 clonal complexes, while the strains, isolated from milk, food and water were included in 9, 6 and 6 clonal complexes, respectively. Three clonal complexes were dominated by clinical isolates, while they were absent in two complexes. Bacterial isolates from food, being a probable source of alimentary toxoinfection, showed low similarity to isolates from stool specimens. The isolates from both sources were classified together in only 4 out of 13 clonal complexes. The large circular and linear plasmids with the sizes between 50 and 200 kb were detected in 24 (39.3%) and 14 (23%) B. cereus strains, respectively. Thirteen (21.3%) strains contained only one plasmid, two plasmids were found in 6 (9.8%) of strains, and three or more plasmids were obtained in 5 (8.2%) of tested strains. The plasmids were confirmed in 30.8% and 40% of isolates from clinical specimens and food and milk samples, respectively. No clear correlation between the PFGE profiles, the source as well as plasmid content among all tested strains was observed.

The microbial contamination and the presence of ß-lactamase producing Gram-negative bacteria in the water and on the surfaces of public recreation water facilities.

The microbiological quality of bathing water and the surfaces of the surrounding pool platforms of two pools was estimated. ESBL- and MBL-producing Gram-negative bacteria isolated from water and surface samples were also studied. The water samples were satisfactory in 31 (86.1 %) out of 36 cases. Pseudomonas aeruginosa as well as Escherichia coli were identified in only 2 (5.5 %) cases. There were no correlations between the HPC and number of enterobacteria in the pool water and those found in the surface samples. Isolated strains were resistant to ticarcillin with clavulanic acid in 52.3 % of cases; all of them were susceptible to ciprofloxacin. The sequences for blaCTX-M were found in 21.6 % of strains, mostly from the groups blaCTX-M9 and blaCTX-M25, whilst the genes for chosen carbapenemases were noted in 15 (17.0 %) of strains. It is necessary to implement new approaches to monitoring resistant bacteria, not only clinical ones but also those found in other public environments.

[First report of carbapenemases in Osijek-Baranja County in imported Enterobacter cloacae isolate in vitro susceptible to carbapenems]. / Prvi opis karbapenemaze u osjecko-baranjskoj zupaniji u unesenom izolatu Enterobactera cloacae in vitro osjetljivom na karbapeneme.

Carbapenems are often the only therapeutic option to treat infections caused by multidrug-resistant Gram-negative bacteria. Emergence of carbapenemases in the isolates of Enterobacteriaceae limits therapeutic options. Carbapenem-resistant Enterobacteriaceae have emerged since 2008 throughout Croatia. In Osijek-Baranja County carbapenem-resistant strains of Enterobacteriaceae were not reported until 2013. The first carbapenem-resistant strain (Enterobacter cloacae) was identified in August 2013 in a patient previously hospitalized at University Hospital Center Zagreb for the treatment of acute lymphoblastic leukemia. Molecular analysis revealed the production of VIM-1 metallo-beta-lactamase (MBL). In spite of the metallo-beta-lactamase production the strain was not resistant to imipenem and meropenem in disk-diffusion and microdilution test. This report shows that routine susceptibility testing carried out in most laboratories does not necessarily detect carbapenemase production in Enterobacteriaceae. Since these enzymes are encoded on mobile genetic elements there is a risk of horizontal spread to other enterobacterial isolates and the development of hospital outbreaks.

Antimicrobial susceptibility and the in vitro postantibiotic effects of vancomycin and ciprofloxacin against Bacillus cereus isolates.

BACKGROUND: Vancomycin and ciprofloxacin were often used in the therapy of infections associated with Bacillus cereus. METHODS: Four B. cereus food and clinical isolates were chosen for determination of time-kill curves and postantibiotic effects (PAE) of ciprofloxacin and vancomycin. RESULTS: According to the minimum inhibition concentration (MIC), breakpoints defined by CLSI for Staphylococcus spp. were all four strains intermediate for vancomycin (MIC = 4 µg/ml) and sensitive to ciprofloxacin (MIC = 0.2 µg/ml) except the strain Bc63 resistant to the last antimicrobial (MIC = 1.6 µg/ml). The lowest CFU values of tested strains were reached after 3-5 hours of exposure to 4 × MIC of vancomycin, and after 6-7 hours exposure to 10 × MIC of ciprofloxacin. The maximum reduction of the CFU in the presence of vancomycin and ciprofloxacin was about 2.46 log10 and 2.48 log10, respectively. The average duration of the PAE of vancomycin and ciprofloxacin was 0.94 and 1.60 hours, respectively. The statistically significant differences between PAEs induced with 3 × MIC, 4 × MIC and 8 × MIC of vancomycin were observed (P < 0.05). Both antibiotics did not affect the sporulation of tested bacterial strains. CONCLUSIONS: The differences in PAE duration were strain and antimicrobial dependent.

Influence of Polyelectrolyte Multilayer Properties on Bacterial Adhesion Capacity.

Bacterial adhesion can be controlled by different material surface properties, such as surface charge, on which we concentrate in our study. We use a silica surface on which poly(allylamine hydrochloride)/sodium poly(4-styrenesulfonate) (PAH/PSS) polyelectrolyte multilayers were formed. The corresponding surface roughness and hydrophobicity were determined by atomic force microscopy and tensiometry. The surface charge was examined by the zeta potential measurements of silica particles covered with polyelectrolyte multilayers, whereby ionic strength and polyelectrolyte concentrations significantly influenced the build-up process. For adhesion experiments, we used the bacterium Pseudomonas aeruginosa. The extent of adhered bacteria on the surface was determined by scanning electron microscopy. The results showed that the extent of adhered bacteria mostly depends on the type of terminating polyelectrolyte layer, since relatively low differences in surface roughness and hydrophobicity were obtained. In the case of polyelectrolyte multilayers terminating with a positively charged layer, bacterial adhesion was more pronounced than in the case when the polyelectrolyte layer was negatively charged.

Postantibiotic effect of colistin alone and combined with vancomycin or meropenem against Acinetobacter spp. with well defined resistance mechanisms.

Previous studies found short postantibiotic effect of colistin on Acinetobacter baumannii. Many studies have evaluated the potential for synergy between colistin and other antibiotics against A. baumannii. The aim of this study was to determine in vitro synergy and postantibiotic effect (PAE) of colistin alone and combined with other antibiotics (vancomycin or meropenem) against eight carbapenem-non-susceptible Acinetobacter spp. strains with defined resistance mechanisms. It was hypothesised that vancomycin or meropenem would prologue the PAE of colistin since it was previously found that they exert synergism with colistin in time-kill kinetics and chequerboard analysis. After exposure of 1 hour colistin alone exhibited the negative ( - 0.07 hour) (OXA-143), short (0.2-1.82 hours) (OXA-24, OXA-58, OXA-72, VIM-1+OXA-23, OXA-58+NDM-1, ISAba1/OXA-69) or moderate PAE (3.2 hours) for OXA-23 positive strain. When combined with vancomycin, the PAE was moderate (1.7-4 hours) with OXA-23, OXA-23+VIM-1, OXA-72 and OXA-24 positive strains while with OXA-58, OXA-143, OXA-58/NDM-1 and ISAba1/OXA-69 positive strains, it was not possible to calculate mean duration of PAE because there was no regrowth after exposure to antibiotics or it was longer than 5 hours. The combination with meropenem resulted in short (0.2 hours) (OXA-143), moderate (2.4-3.73 hours) (OXA-24, OXA-58, OXA-23, OXA-23+VIM-1), long PAE of 5 hours (OXA-23) or longer than 5 hours (OXA-58+VIM-1, ISAba1/OXA-69). From the clinical point of view, the prolongation of colistin PAE when combined with other antibiotics could provide a rationale for the modification of the dosing interval and could be important for the optimization of the treatment regimen and the minimization of drug-induced side effects.

Nursing Home as a Reservoir of Carbapenem-Resistant Acinetobacter baumannii.

Acinetobacter baumannii is an increasingly common pathogen in healthcare settings globally. It is frequently resistant to multiple antimicrobial agents and there are recent reports on strains that are pandrug resistant. The aim of the study was to characterize the mechanisms of carbapenem resistance of A. baumannii strains from a nursing home in Zagreb and to genotype the strains. Antimicrobial susceptibility testing was performed by the broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI). PCR was used to detect genes encoding carbapenemases of groups A, B, and D and extended-spectrum ß-lactamases. Genotyping of the strains was performed by rep-PCR. All strains were found to be resistant to ceftazidime, cefotaxime, ceftriaxone, cefepime, piperacillin/tazobactam, imipenem, meropenem, and ciprofloxacin. All, but one strain, were resistant to gentamicin. PCR revealed blaOXA-23 genes in 14, blaOXA-24 in 5, and blaVIM in 11 strains. All strains positive for blaVIM genes coharbored blaOXA-23 genes. The 14 strains with OXA-23 belonged to ICL II, whereas the 5 strains positive for blaOXA-24 belonged to ICL I. In contrast to hospitals where OXA-24/40-like ß-lactamases and OXA-58 were the most prevalent, OXA-23-like ß-lactamases are the dominant group in the nursing home. OXA-58-like ß-lactamase, which is the most widespread group, was not found. Acquisition of blaMBL genes in A. baumannii strains was observed. Rep-PCR identified two clones. Two strains A10 and A13 were alocated to a novel sequence type ST 637. Nursing homes can act as a source of dissemination of blaOXA and blaMBL genes in the environment and the possible influx to the hospital environment.