Identification through MALDI-TOF mass spectrometry and antimicrobial susceptibility profiling of bacterial pathogens isolated from sow urinary tract infection.

BACKGROUND: Urinary tract infection (UTI) is a common disease in sows due to intensification of pig production. Despite direct economic losses, UTI prevalence and respective microbial identification are still poorly studied. OBJECTIVE: The aims of this study were to identify the causative agents of UTI in sows through MALDI-TOF MS and to characterize their antimicrobial resistance profiles. MATERIALS AND METHODS: Urine samples from 300 sows of three herds from São Paulo State (Brazil) were screened for UTI; suggestive samples were submitted to bacterial isolation. Species identification was performed by MALDI-TOF MS and susceptibility profiles were determined using disc diffusion method. RESULTS: 128 samples suggestive of UTI were analyzed; 48% of the animals presented UTI caused by a single pathogen, while the remaining 52% presented mixed infection. Escherichia coli stood out with the highest frequency among both single and mixed infections. The Gram-positive were exclusively associated with 27% of single infections. The mixed infections were further classified into 49 profiles. The high frequency of multiresistant profiles stood out for most of the studied isolates. CONCLUSIONS: MALDI-TOF MS enabled the identification of rare pathogens related to UTI which may represent higher risk for porcine health, especially considering high frequency of multiresistant profiles.

Molecular and antimicrobial susceptibility characterization of Globicatella sulfidifaciens isolated from sow's urinary tract infection.

BACKGROUND: The Globicatella genus comprises Gram-positive, facultative anaerobic, α-hemolytic and catalase negative cocci morphologically and phenotypically very similar to Streptococcus and Aerococcus genus which can lead to misidentification and underestimation of this pathogen. Globicatella species have already been isolated from human and animals with heart and brain disorders. Their clinical relevance in animals, and its zoonotic potential, remains unknown due to the difficulty in their identification. OBJECTIVE: To present the isolation, phenotypic and molecular characterization of G. sulfidifaciens from urinary tract infection in sows. MATERIALS AND METHODS: Urine samples from 140 sows of two swine herds located in São Paulo State (Brazil) yielded the isolation of three presumptive G. sulfidifaciens strains. Identification and species confirmation were done by MALDI-TOF MS and 16S rRNA sequencing. Strains were further characterized by single enzyme amplified fragments length polymorphism (SE-AFLP) and broth microdilution techniques. RESULTS: All three isolates were confirmed as G. sulfidifaciens. The SE-AFLP genotyping resulted in distinct fingerprint patterns for each strain. All isolates presented high MIC values to tetracycline, sulphonamides, aminoglycosides and tylosin tartrate, which present high usage in human and animal medicine. CONCLUSIONS: Globicatella sulfidifaciens could be related to sporadic urinary tract infections in swine and appear to present alarming antimicrobial susceptibility profile. It is necessary to differentiate Streptococcus-like microorganisms in routine laboratory diagnostics for the correct identification of underestimated species potentially pathogenic to animals.

Evaluation of protein spectra cluster analysis for Streptococcus spp. identification from various swine clinical samples.

Traditional microbiological methods enable genus-level identification of Streptococcus spp. isolates. However, as the species of this genus show broad phenotypic variation, species-level identification or even differentiation within the genus is difficult. Herein we report the evaluation of protein spectra cluster analysis for the identification of Streptococcus species associated with disease in swine by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A total of 250 S. suis-like isolates obtained from pigs with clinical signs of encephalitis, arthritis, pneumonia, metritis, and urinary or septicemic infection were studied. The isolates came from pigs in different Brazilian states from 2001 to 2014. The MALDI-TOF MS analysis identified 86% (215 of 250) as S. suis and 14% (35 of 250) as S. alactolyticus, S. dysgalactiae, S. gallinaceus, S. gallolyticus, S. gordonii, S. henryi, S. hyointestinalis, S. hyovaginalis, S. mitis, S. oralis, S. pluranimalium, and S. sanguinis. The MALDI-TOF MS identification was confirmed in 99.2% of the isolates by 16S rDNA sequencing, with MALDI-TOF MS misidentifying 2 S. pluranimalium as S. hyovaginalis. Isolates were also tested by a biochemical automated system that correctly identified all isolates of 8 of the 10 species in the database. Neither the isolates of the 3 species not in the database ( S. gallinaceus, S. henryi, and S. hyovaginalis) nor the isolates of 2 species that were in the database ( S. oralis and S. pluranimalium) could be identified. The topology of the protein spectra cluster analysis appears to sustain the species phylogenetic similarities, further supporting identification by MALDI-TOF MS examination as a rapid and accurate alternative to 16S rDNA sequencing.

Molecular and antimicrobial susceptibility profiling of atypical Streptococcus species from porcine clinical specimens.

The Streptococcus species present broad phenotypic variation, making identification difficult using only traditional microbiological methods. Even though Streptococcus suis is the most important species for the worldwide swine industry, other Streptococcus species appear to be able to cause disease in swine and could represent a higher underestimated risk for porcine health. The aim of this study was to identify Streptococcus-like isolates by MALDI-TOF MS and 16S rRNA sequencing and further molecular and antibiotic susceptibility characterization of the atypical Streptococcus species capable of causing disease in swine. Fifty presumptive Streptococcus isolates from diseased pigs isolated from different Brazilian States between 2002 and 2014 were evaluated. Among the studied isolates, 26% were identified as Streptococcus hyovaginalis, 24% as Streptococcus plurianimalium, 12% as Streptococcus alactolyticus, 10% as Streptococcus hyointestinalis, and the remaining isolates belonged to Streptococcus henryi (6%), Streptococcus thoraltensis (6%), Streptococcus gallolyticus (6%), Streptococcus gallinaceus (4%), Streptococcus sanguinis (4%), and Streptococcus mitis (2%). The Streptococcus isolates were successfully identified by spectral cluster analysis and 16S rRNA sequencing with 96% of concordance between the techniques. The SE-AFLP analysis also supported Streptococcus species distinction and enabled further observation of higher genetic heterogeneity intra-species. The identified Streptococcus species presented variable MIC values to ß-lactams, enrofloxacin and florfenicol, and high resistance rates to tetracyclines and macrolides, which appear to be directly related to the industry's antimicrobial usage and resistance selection.

Molecular and antimicrobial susceptibility profiling of Streptococcus dysgalactiae isolated from swine.

Streptococcus dysgalactiae subspecies equisimilis and dysgalactiae were isolated from swine clinical specimens. The subspecies equisimilis presented 2 clonal patterns with 85% genetic similarity, whereas subspecies dysgalactiae presented distinct band pattern with less than 80% similarity with equisimilis genotypes. Isolates presented high MIC values to tetracyclines, danofloxacin, spectinomycin, tiamulin, and clindamycin.

Characterization of Streptococcus suis through serotyping, SE-AFLP and virulence profile / Caracterização de Streptococcus suis por sorotipagem, SE-AFLP e perfil de virulência

Streptococcus suis is one of most important pathogens in the swine industry worldwide. Despite its importance, studies of S. suis characterization in South America are still rare. This study evaluates S. suis isolates from distinct Brazilian states, from 1999 to 2004, and its molecular and serological characterization. A total of 174 isolates were studied. S. suis identification was confirmed by PCR and isolates were further serotyped and genotyped by SE-AFLP and amplification of virulence markers. Serotype 1, 2, 3, 4, 7, 18, 22 and 32 were identified among the studied isolates, and only 4% were characterized as non-typeable. The mrp+/epf+/sly+ genotype was the most frequent. The SE-AFLP analysis resulted in 29 patterns distributed in three main clusters with over 65% of genetic similarity. Isolates presented a slight tendency to cluster according to serotype and origin; however, no further correlation with virulence genotypes was observed.(AU)

Streptococcus suis é um dos patógenos de maior importância para indústria suinícola mundial. Apesar de sua importância, a caracterização de isolados de S. suis na América do Sul ainda é pouco descrita. O presente estudo descreve a avaliação de isolados de S. suis provenientes de diferentes Estados brasileiros, e sua caracterização sorológica e molecular. Foram avaliados 174 isolados de S. suis e os mesmos foram submetidos a SE-AFLP e pesquisa de marcadores de virulência. Os sorotipos 1, 2, 3, 4, 7, 18, 22 e 32 foram identificados dentre os isolados estudados e apenas 4% foram caracterizados como não tipáveis. O perfil de virulência mrp+/epf+/sly+ foi o mais frequente. A análise do SE-AFLP resultou em 29 perfis distribuídos em três grupos principais com mais de 65% de similaridade genética. Os isolados apresentaram tendência de se agrupar segundo origem e sorotipo; no entanto, não foi observada correlação entre os grupamentos e os perfis de virulência.(AU)

Molecular and antibiotic susceptibility characterization of Aerococcus viridans isolated from porcine urinary infection.

Aerococcus viridans has been reported as a human and animal pathogen causing urinary tract infection, arthritis, pneumonia, meningitis and endocarditis. Routinely, A. viridans is not surveyed in clinical diagnosis laboratories and commonly is misidentified as other bacteria. There is no concrete data on the prevalence and impact of the pathogen to both human and animal health. In the present study, we report the isolation and molecular and antibiotic susceptibility characterization of A. viridans strains from porcine urinary infections. A total of 22 isolates were identified as A. viridans by MALDI-TOF MS and confirmed by 16S rRNA gene sequencing. Isolates were genotyped by single enzyme amplified fragments length polymorphism (SE-AFLP) that resulted in 19 clusters of which 81.2% were composed by single isolates. The high genetic heterogeneity corroborates previous studies and appears to be a particularity of A. viridans. The minimal inhibitory concentration (MIC) values also presented variability especially for ceftiofur, fluoroquinolones and aminoglycosides. The high MICs of aminoglycosides, tetracyclines and macrolides seen among the A. viridans corroborate previous reports and the widespread veterinary usage of these antibiotics demand attention for the implication of A. viridans infection to both human and animal health.