Occurrence of multidrug-resistant Enterococcus faecium isolated from environmental samples.

Enterococcus species are present in the microbiota of humans and animals and have also been described in the environment. Among the species, Enterococcus faecium is one of the main pathogens associated with nosocomial infections worldwide. Enterococcus faecium isolates resistant to different classes of antimicrobials have been increasingly reported, including multidrug-resistant (MDR) isolates in environmental sources, which is worrying. Therefore, this study aimed to characterize E. faecium isolates obtained from soil and water samples regarding antimicrobial resistance and virulence determinants. A total 40 E. faecium isolates were recovered from 171 environmental samples. All isolates were classified as MDR, highlighting the resistance to the fluoroquinolones class, linezolid and vancomycin. Furthermore, high-level aminoglycoside resistance and high-level ciprofloxacin resistance were detected in some isolates. Several clinically relevant antimicrobial resistance genes were found, including vanC1, ermB, ermC, mefAE, tetM, tetL, ant(6')-Ia, ant(4')-Ia, aph(3')-IIIa and aac(6')-Ie-aph(2″)-Ia. Three virulence genes were detected among the MDR E. faecium isolates, such as esp, gelE and ace. The results of this study contribute to a better understanding of MDR E. faecium isolates carrying antimicrobial resistance and virulence genes in environmental sources and report for the first time in the world the presence of vanC1-producing E. faecium isolated from soil.

New STs in multidrug-resistant Acinetobacter baumannii harbouring ß-lactamases encoding genes isolated from Brazilian soils.

AIMS: We investigated the resistance profile, presence of ß-lactamases encoding genes and the clonal relationships in Acinetobacter baumannii isolated from Brazilian soils. METHODS AND RESULTS: Soil isolates of A. baumannii were subjected to antimicrobial susceptibility testing by disk diffusion and minimum inhibitory concentration methods. Different ß-lactamases encoding genes were screened by PCR and the molecular typing of these isolates was performed through the multilocus sequence typing. Non-susceptibility to different antibiotics was found, since environmental isolates were classified as multidrug-resistant. The blaSHV gene was the most prevalent, followed by blaGES. All sequence types (STs) found (ST1584, ST1607, ST1608, ST1609, ST1610, ST1611 and ST1612) were described for the first time in this study. CONCLUSION: The wide variety of new alleles and new STs detected in the present study indicates a divergent population compared to studies that are carried out in the clinical environment and points to an even larger genetic diversity within the species than was anticipated. SIGNIFICANCE AND IMPACT OF THE STUDY: A number of the environmental isolates represented multidrug-resistant strains, a phenotype that has been more commonly reported for clinical isolates of A. baumannii; the detection of several ß-lactamase encoding genes in the investigated isolates is of great concern suggesting that there is a large reservoir of these resistance genes in the environment.

Molecular genotyping and epidemiology of Mycobacterium tuberculosis isolates obtained from inmates of correctional institutions of Campinas, Southeast Brazil

The objective of this study was to investigate the possible transmission of tuberculosis among 39 inmates with positive Mycobacterium tuberculosis smears in four correctional institutions located in Campinas City, SP, Brazil over a 19-month period. Fifty-one M. tuberculosis isolates from these inmates were characterized according to the number of IS6110 insertion elements present in their genomic DNA. The number of insertion elements in M. tuberculosis isolates varied from two to twelve. The dendrogram of similarity resulted in the grouping the isolates in six main clusters. These results, associated to epidemiological data, suggested the transmission of tuberculosis among inmates of the same and different institutions inmates. Univariate analysis of epidemiological data (total delay for beginning of treatment, previous treatment, and HIV status) and clustering occurrence showed that only "previous treatment" (OR = 7.65, p = 0.032) was associated with the possible transmission of tuberculosis in the studied prisons.

Molecular genotyping and epidemiology of Mycobacterium tuberculosis isolates obtained from inmates of correctional institutions of Campinas, Southeast Brazil.

The objective of this study was to investigate the possible transmission of tuberculosis among 39 inmates with positive Mycobacterium tuberculosis smears in four correctional institutions located in Campinas City, SP, Brazil over a 19-month period. Fifty-one M. tuberculosis isolates from these inmates were characterized according to the number of IS6110 insertion elements present in their genomic DNA. The number of insertion elements in M. tuberculosis isolates varied from two to twelve. The dendrogram of similarity resulted in the grouping the isolates in six main clusters. These results, associated to epidemiological data, suggested the transmission of tuberculosis among inmates of the same and different institutions inmates. Univariate analysis of epidemiological data (total delay for beginning of treatment, previous treatment, and HIV status) and clustering occurrence showed that only 'previous treatment' (OR = 7.65, p = 0.032) was associated with the possible transmission of tuberculosis in the studied prisons.

DNA sequencing of a pathogenicity-related plasmid of an avian septicemic Escherichia coli strain.

A 43-MDa conjugative plasmid isolated from an avian septicemic Escherichia coli (APEC) strain possessing genes related to the adhesion and invasion capacities of in vitro-cultured cells was sequenced. The results demonstrated that the 43-MDa plasmid harbors bacterial pathogenicity-related sequences which probably allow the wild-type pathogenic strain to adhere to and invade tissues and to cause septicemia in poultry. The existence of homology sequences to sequences belonging to other human pathogenic Enterobacteriaceae like Escherichia coli O157:H7, Shigella and Salmonella was also observed. The presence of these sequences in this plasmid could indicate that there is horizontal genetic transfer between bacterial strains isolated from different host species. In conclusion, the present study suggests that APEC strains harbor high-molecular weight plasmids that present pathogenicity-related sequences and that these are probably responsible for the pathogenicity exhibited by these strains. The presence of human pathogenicity-associated sequences in APEC conjugative plasmids suggests that these strains could represent a zoonotic risk.

DNA sequencing of a pathogenicity-related plasmid of an avian septicemic Escherichia coli strain

A 43-MDa conjugative plasmid isolated from an avian septicemic Escherichia coli (APEC) strain possessing genes related to the adhesion and invasion capacities of in vitro-cultured cells was sequenced. The results demonstrated that the 43-MDa plasmid harbors bacterial pathogenicity-related sequences which probably allow the wild-type pathogenic strain to adhere to and invade tissues and to cause septicemia in poultry. The existence of homology sequences to sequences belonging to other human pathogenic Enterobacteriaceae like Escherichia coli O157:H7, Shigella and Salmonella was also observed. The presence of these sequences in this plasmid could indicate that there is horizontal genetic transfer between bacterial strains isolated from different host species. In conclusion, the present study suggests that APEC strains harbor high-molecular weight plasmids that present pathogenicity-related sequences and that these are probably responsible for the pathogenicity exhibited by these strains. The presence of human pathogenicity-associated sequences in APEC conjugative plasmids suggests that these strains could represent a zoonotic risk.

Determination of the clonal structure of avian Escherichia coli strains by isoenzyme and ribotyping analysis.

Forty-nine avian Escherichia coli strains isolated from different outbreak cases of septicemia (24), swollen head syndrome (14) and omphalitis (11), and 20 strains isolated from poultry with no signs of the mentioned illnesses, for a total of 69 strains, were typed by isoenzyme profile and ribotyping analysis by restriction fragment length polymorphism (RFLP). Isoenzyme analysis discriminated better among strains (0-0.07 degree of genetic dissimilarity) than ribotyping analysis (0- 0.02 degree of genetic dissimilarity). The enzyme profiles of the E. coli isolates allowed the identification of 33 clones that were organized into six main clusters (A-F). Cluster A comprised 87% of the pathogenic strains and had no commensal strains, while commensal strains were assigned to clusters B-F. The ribotyping analysis resulted in a more heterogenous distribution of strains but most of those that cause the same type of infection were kept close together. Taken as a whole, these results demonstrate that pathogenic clones are more similar to one another when compared with commensal strains and suggest a correlation between the genetic background and the pathogenic characteristics of avian pathogenic E. coli strains.