Antimicrobial resistance in Aeromonas species isolated from aquatic environments in Brazil.

AIM: The current study was conducted to determine the antimicrobial resistance profile and genetic relatedness of Aeromonas sp. isolated from healthcare and urban effluents, wastewater treatment plant (WWTP) and river water. METHODS AND RESULTS: We detected the presence of genes conferring resistance to ß-lactam, quinolone and aminoglycoside. Multilocus sequence typing was carried out to differentiate the strains, and multilocus phylogenetic analysis was used to identify the species. A total of 28 cefotaxime-resistant Aeromonas sp. strains were identified, harbouring uncommon Guiana-extended-spectrum (GES)-type ß-lactamases (GES-1, GES-5, GES-7 and GES-16). Multidrug-resistant Aeromonas sp. were found in hospital wastewater, WWTP and sanitary effluent, and A. caviae was identified as the most prevalent species (85·7%). CONCLUSION: The release of untreated healthcare effluents, presence of antimicrobials in the environment, in addition to multidrug-resistant Aeromonas sp., are all potential factors for the spread of resistance. SIGNIFICANCE AND IMPACT OF THE STUDY: We identified a vast repertoire of antimicrobial resistance genes (ARG) in Aeromonas sp. from diverse aquatic ecosystems, including those that encode enzymes degrading broad-spectrum antimicrobials widely used to treat healthcare-associated infections. Hospital and sanitary effluents serve as potential sources of bacteria harbouring ARG and are a threat to public health.

Nosocomial infections with metallo-beta-lactamase-producing Pseudomonas aeruginosa: molecular epidemiology, risk factors, clinical features and outcomes.

BACKGROUND: Metallo-ß-lactamases (MBLs) have emerged as one of the most important bacterial resistance mechanisms because of their ability to hydrolyse virtually all ß-lactam agents. MBL-producing Pseudomonas aeruginosa (MBL-PA) are an important cause of nosocomial infections, particularly in intensive care units (ICUs), where they are associated with serious infections and present a significant clinical risk. AIM: To assess the molecular epidemiology, risk factors and outcomes of nosocomial infections caused by MBL-PA in a teaching hospital in Southern Brazil. METHODS: From January 2001 to December 2008, 142 carbapenem-resistant P. aeruginosa strains were isolated from distinct clinical samples from hospitalized patients. These isolates were screened for MBLs, and underwent polymerase chain reaction, sequencing and pulsed-field gel electrophoresis (PFGE). Patients infected with carbapenem-resistant MBL-PA were considered as cases, and patients infected with non-MBL-PA were considered as controls. FINDINGS: Eighty-four of 142 patients with positive carbapenem-resistant P. aeruginosa cultures met the criteria of the Centers for Disease Control and Prevention for infection. Fifty-eight patients were infected with MBL-PA (69%) and 26 patients were infected with non-MBL-PA (31%). Multi-variate analysis revealed that ICU stay [P = 0.003, odds ratio (OR) 4.01, 95% confidence interval (CI) 1.15-14.01] and urinary tract infection (P = 0.001, OR 9.67, 95% CI 1.72-54.48) were important risk factors for MBL-PA infection. Patients infected with MBL-PA showed faster onset of infection (P = 0.002) and faster progression to death (P = 0.04). CONCLUSIONS: These results showed the severity of MBL-PA infections, and demonstrated the urgent need for strategies to improve infection control measures to prevent an increase in these nosocomial infections.

Evaluation of the Alere Pima™ for CD4+ T lymphocytes counts in HIV-positive outpatients in Southern Brazil.

CD4 + lymphocyte counts are routinely ordered during the early phases of antiretroviral therapy and for prophylaxis of opportunistic infections in HIV-positive patients. Flow cytometry is the standard methodology for CD4 counts in Brazilian reference laboratories. However, these laboratories are located in large cities, frequently distant from patients, thus limiting patient access and delaying results. We compared a point-of-care test with flow cytometry determination of CD4(+) T lymphocyte counts in HIV patients. We analysed 107 consecutive samples by both methods. Overall, the point-of-care test performed well, with excellent agreement between it and the standard method. Test results were concordant for patients with CD4(+) T lymphocyte values above and below 200 cells/mm (3). The performance characteristics obtained were sensitivity 94% (95% CI 89.5-98.5%), specificity 93% (95% CI 88.2-97.8%), positive predictive value 86% (95% CI 79.4-92.6%), and negative predictive value 97% (95% CI 94-100%). The high sensitivity and specificity of the point-of-care test methodology suggest its utility as an alternative method for rapid measurement of CD4(+) T lymphocytes in patients with limited access to reference laboratories, enabling prompt therapeutic intervention for patients at risk of progression to AIDS.

Characterization of a divergent vanD-type resistance element from the first glycopeptide-resistant strain of Enterococcus faecium isolated in Brazil.

Enterococcus faecium 10/96A from Brazil was resistant to vancomycin (MIC, 256 microg/ml) but gave no amplification products with primers specific for known van genotypes. A 2,368-bp fragment of a van cluster contained one open reading frame encoding a peptide with 83% amino acid identity to VanH(D), and a second encoding a D-alanine-D-lactate ligase with 83 to 85% identity to VanD. The divergent glycopeptide resistance phenotype was designated VanD4.

Characterisation of diarrhoeagenic Escherichia coli clones by ribotyping and ERIC-PCR.

The ability of ribotyping and enterobacterial repetitive intergenic concensus-polymerase chain reaction (ERIC-PCR) to discriminate diarrhoeagenic Escherichia coli clones of 122 strains belonging to 26 distinct serotypes was evaluated. The 26 serotypes corresponded to 24 ribotypes and 25 ERIC-types. Correlation between multilocus enzyme electrophoresis, ERIC-PCR and ribotyping was c. 90% for the dominant ribotypes. Related clones such as O55:H7 and O157:H7 presented similar ribotypes and clustered together in a dendrogram, and the two divergent clonal groups of enteropathogenic E. coli (EPEC) and enterohaemorrhagic E. coli (EHEC) were included in distinct branches. The results suggest the possibility of applying these two simpler techniques as tools to identify clones of diarrhoeagenic E. coli.

Epidemiology of Pseudomonas aeruginosa infection in cystic fibrosis and the use of strain genotyping.

We describe a study of the epidemiology of Pseudomonas aeruginosa (PA) infection in a group of adults with cystic fibrosis who attended a week-long summer camp in the U.K. Sputum samples were collected from 17 patients at the beginning and at the end of the holiday period. Examination of previous sputum samples had identified 11 patients who were chronically colonised with PA. They shared accommodation during the holiday. The sputum samples from these 11 patients were analysed so as to identify the strains of PA by their genotypic characters. All patients were colonised by unique strains before the beginning of the holiday, with the exception of two pairs of patients whose isolates were indistinguishable. After the holiday, eight of the 11 patients harboured strains of the same genotype as was found in their pre-holiday specimens. In three patients, a strain present post-holiday was different from that found in the pre-holiday specimen. In addition, in the case of one patient, two different genotypes were found in the pre-holiday specimen, only one of which was present after the holiday. Evidence of cross-infection of PA during the holiday was not found. Even so, evidence of person-to-person transmission of PA both within the hospital environment and through social contact is presented and discussed.