Phenotype characterization of Staphylococcus species strains isolated from buffalo (Bubalus bubalis) milk.

The objective of the current study was to isolate and identify phenotypes of Staphylococcus spp. strains derived from buffalo (Bubalus bubalis) milk. A total of 548 milk samples from 137 buffalo were cultured in Columbia agar enriched with 5% defibrinated sheep blood. Determination of the capacity of Staphylococcus aureus to produce enterotoxins A-D and toxic shock syndrome toxin-1 (TSST-1) was achieved by reverse passive latex agglutination (RPLA). Antimicrobial sensitivity of S. aureus strains was evaluated using the disk diffusion technique, and ß-lactamase detection was achieved using the chromogenic test with paper discs impregnated with nitrocefin. From all the mammary quarters examined, 36 (10.8%) were positive for Staphylococcus spp., 83.3% were coagulase-negative staphylococcus (CNS), 11.1% were coagulase-positive staphylococcus (CPS), and 5.6% were of CPS+CNS positive. All isolates of S. aureus produced at least 1 toxin and 5 out of 6 isolates (83.0%) produced ß-lactamase. One hundred percent of S. aureus isolates were sensitive to methicillin and amoxicillin + clavulanic acid, and resistant to ampicillin, penicillin, and oxacillin. Analysis of the results obtained in the current study highlight the epidemiologic importance of buffalo milk regarding the production of enterotoxins and TSST-1 and the potential risk to public health.

Significância clínica de estafilococos coagulase-negativa isolados de recém-nascidos / Clinical significance of coagulase-negative staphylococci isolated from neonates

Objetivo: avaliar a significância clínica de estafilococos coagulase-negativa (ECN) isolados de processos infecciosos em recém-nascidos da unidade neonatal do Hospital das Clínicas da Faculdade de Medicina de Botucatu.Método: as linhagens de ECN isoladas foram identificadas eclassificadas em significativas e contaminantes, com base em uma série de dados clínicos e laboratoriais obtidos dos prontuários dos pacientes internados na unidade neonatal. Foram pesquisados os dados referentes a fatores perinatais de risco para infecção, evolução clínica, alterações do hemograma e/ou positividade de proteína C-reativa e antibioticoterapia.Resultados: das 117 linhagens de ECN isoladas, 60 (51,3por cento)foram classificadas como significativas, e 57 (48,7por cento) como contaminantes. Das 54 crianças com infecção por ECN, 43 (79,6por cento) eram prematuras, e 27 (50,0por cento) tiveram peso ao nascimento < 1.500g. A maioria das crianças com infecção por ECN estava submetida a dois ou mais procedimentos invasivos (77,8por cento), incluindo o uso de cateter(88,9por cento), nutrição parenteral (64,8por cento) e ventilação mecânica (61,1por cento).O S.epidermidis foi a espécie mais freqUentemente isolada (77,8por cento), e mais associada com infecção (86,7por cento) do que com contaminação (68,4por centi). Outras espécies de ECN, incluindo duas linhagens de s.haemolyticus, três linhagens de s. lugdunensis, uma linhagem de S. simulans, uma de S. warneri e uma linhagem de S. xylosus também foram isoladas de crianças com evidência clínica de pneumonia, nterocolite necrosante e sepse.Conclusão: a maioria dos recém-nascidos com infecção por ECN apresentou...

[Clinical significance of coagulase-negative staphylococci isolated from neonates]. / Significância clínica de estafilococos coagulase-negativa isolados de recém-nascidos.

OBJECTIVE: To evaluate the clinical significance of coagulase-negative staphylococci (CNS) isolated from newborns' infections at Neonatal Unit of Hospital das Clínicas da Faculdade de Medicina de Botucatu. METHODS: The CNS strains isolated were identified and classified as clinically significant and contaminant, based on a series of clinical and laboratory data obtained from patients who stayed in the Neonatal Unit. The following data were analyzed: risk factors for infections, clinical evolution, abnormal blood cell counts and/or C-reactive protein and antibiotic therapy. RESULTS: Among the 117 CNS strains isolated, 60 (51.3%) were classified as significant and 57 (48.7%) as contaminant. Among the 54 infants infected by CNS, 43 (79.6%) presented very low birthweight (<1,500 g). Most of the infants infected by CNS were submitted to two or more invasive procedures (77.8%), including use of catheter (88.9%), parenteral nutrition (64.8%) and mechanical ventilation (61.1%). Staphylococcus epidermidis was the most frequently isolated species (77.8%) and more often associated with infection (86.7%) than with contamination (68.4%). Other species of CNS, including two strains of S. haemolyticus, three strains of S. lugdunensis, one strain of S. simulans, one strain of S. warneri and one strain of S. xylosus were also isolated from infants with clinical evidence of pneumonia, necrotizing enterocolitis and sepsis. CONCLUSIONS: Most newborns infected by CNS presented important risk factors for infection onset, including birthweight <1,500 g, foreign body presence and previous use of antibiotics. The identification of CNS species constitutes a useful marker of infection, since S. epidermidis was the species more frequently associated with infection.