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PubMed1985

Rapid species identification of group C streptococci isolated from horses.

Two commercial systems, the API 20S (Analytab Products, Plainview, N.Y.) and the Rapid Strep (API System S.A., Montalieu-Vercieu, France), were evaluated for ease of use and accuracy in the rapid identification of group C streptococci isolated from horses. A total of 85 Streptococcus isolates were tested, including S. equi (67 isolates), S. zooepidemicus (13 isolates), and S. equisimilis (5 isolates). All S. equi and S. zooepidemicus isolates were correctly identified within 24 h by the Rapid Strep system. Specific grouping sera was necessary to distinguish between S. equisimilis and group G or L strains. The API 20S system did not provide species identification of any of these isolates. An identification of randomly selected isolates to species level was performed by conventional methods and confirmed the identification derived through the Rapid Strep system. Our results indicate that the Rapid Strep system is a valuable aid for species identification of equine isolates of group C streptococci.

Animals↗

PubMed1991

Inhibitory effects of fibrinogen on phagocytic killing of streptococcal isolates from humans, cattle and horses.

The effects of fibrinogen on phagocytic killing of Streptococcus dysgalactiae from cattle and S. equi from horses were studied in comparison to that of S. pyogenes from humans. Phagocytic killing was determined by a fluorometric microassay using glass adherent polymorphonuclear neutrophils (PMN) from the respective host species, preopsonization with homologous sera led to a dose-dependent increase in phagocytic killing of all streptococcal cultures, preincubation of streptococci with fibrinogen significantly inhibited their phagocytic killing. Fibrinogen had no effect on phagocytic killing of non-fibrinogen binding S. agalactiae cultures. Further characterization studies with S. dysgalactiae and S. pyogenes revealed that a partial inhibition of phagocytic killing could also be achieved by preincubation with monomeric beta-chains of fibrinogen. Digestion of the fibrinogen binding sites on streptococci with proteases resulted in an almost complete loss of the inhibitory effects of fibrinogen on phagocytic killing. It could thus be concluded that by binding fibrinogen animal pathogenic streptococci could evade phagocytic killing in a similar manner as M protein carrying S. pyogenes isolates from human infections.

Animals↗

PubMedDate not supplied

[Utility of prolonged incubation and terminal subcultures of blood cultures from immunocompromised patients].

The value of blind terminal subcultures (7 and 30 days) and prolonged incubation (30 days) of blood cultures from immunosuppressed patients was analyzed in the Fundación Favaloro, the Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia and the Hospital de Niños Ricardo Gutiérrez. A total of 2707 blood cultures and 369 patients were included (transplantation of solid organs 154, oncohematologic disorders 106 and solid tumors 109). Bact-Alert bottles were incubated at 35 degrees C for 30 days in the Bact-Alert System. Bottles with positive signals were routinely removed, and aliquots of the broth were Gram stained and subcultured aerobically in chocolate agar and Sabouraud agar. A total of 136 bacteremic episodes were obtained. The positivization time of blood cultures was 81.6% at 24 h, 93.3% at 48 h, 94.5% at 72 h and 97.7% within 7 days. Only 3 (2.2%) episodes were positive by blind terminal subcultures and 1 (0.75%) by prolonged incubation (14 days). The median time and range of positivization in hours were 13.8 and 2.2-168, respectively. The microorganisms isolated were coagulase negative staphylococci (n = 24), Klebsiella pneumoniae (n = 22), Staphylococcus aureus (n = 21), Escherichia coli (n = 18), Acinetobacter spp (n = 9), Candida spp (n = 8), Pseudomonas aeruginosa (n = 6), Enterobacter cloacae (n = 5), Stenotrophomonas maltophilia (n = 5), Enterococcus faecalis, Salmonella spp and Capnocytophaga sputigena (n = 2), Enterobacter aerogenes, Enterococcus faecium, Citrobacter diversus, Candida albicans, Klebsiella oxytoca, Chryseomonas luteola, Serratia marcescens, Abiotrophia spp, Campylobacter jejuni, Moraxella catarrhalis, Moraxella urethralis, Neisseria sicca, beta hemolytic group G streptococci, Rhodococcus equi, Micrococcus spp, Cryptococcus neoformans and Streptococcus mitis (n = 1). In our experience, blind terminal subcultures and prolonged incubation of blood cultures from immunosuppressed patients are unnecessary and cost expensive.

Bacteremia↗

PubMed1982

Influence of bacterial products on the motility of stallion spermatozoa.

Sterile filtrates were prepared from equine isolates of Klebsiella pneumoniae (genitalium), Proteus mirabilis, Pseudomonas aeruginosa, Escherichia coli, Streptococcus zooepidemicus, Streptococcus equisimilis, Actinobacillus equuli, and Corynebacterium equi and mixed individually with extended stallion semen. When diluted in the extended semen the filtrates represented bacterial populations of 0.5 x 10(6), 1 x 10(6), 2 x 10(6) and 4 x 10(6) cells/ml. pH values were recorded for each filtrate. Specimens were monitored for percentage motile spermatozoa at 30-min intervals until they reached 10% or less for 2 consecutive observations. All specimens were maintained at 25 degrees C in a water bath. Ten specimens were examined from each of 5 clinically normal stallions. The major reduction in percentage motile spermatozoa as compared to the control sample occurred before the first observation. From this point the rate of deterioration in motility in the filtrates approximated that of the control. The differences detected between the filtrates and control in percentage motile sperm cells were all statistically significant at P less than 0.01.

Animals↗

PubMed1988

Adherence of streptococcal isolates from cattle and horses to their respective host epithelial cells.

Adherence of Streptococcus dysgalactiae isolates from cattle and S equi isolates from horses to their respective host epithelial cells was compared with the adherence of S pyogenes to human epithelial cells. The adherence was quantitatively determined by use of fluorescein-labeled streptococci. All 3 streptococcal species adhered selectively to their respective host cells. The mechanism of adherence was evaluated by binding studies with adhesive plasma protein, fibronectin. Although all 3 streptococcal species bound fibronectin, S dysgalactiae and S equi interacted preferentially with a 210-kilodalton (kD) C-terminal fragment of fibronectin, whereas S pyogenes bound only a 29-kD N-terminal fragment. A synthetic peptide Gly-Arg-Gly-Asp-Ser, representing the host cell attachment site of fibronectin, partially inhibited the binding of fibronectin and of its 210 kD fragment to S dysgalactiae, but not to S equi. The binding of fibronectin and its 29-kD fragment to S pyogenes was not inhibited by Gly-Arg-Gly-Asp-Ser. These differences in binding activities corresponded to the ability of fibronectin to mediate the adherence of the streptococci to the epithelial cells: fibronectin strongly inhibited the adherence of S pyogenes and S equi to the epithelial cells, but only weakly inhibited that of S dysgalactiae.

Animals↗

PubMed1997

[Meropenem: microbiologic perspective].

Meropenem is a beta-lactamic carbapenem derived from thienamycin and is structurally characterized by the presence of a beta-methyl group in position C1 which confers stability to the molecule versus renal dehydropeptidase 1 (DHP-1), thereby making the coadministration of an enzyme inhibitor unnecessary. Its esterochemical configuration of the lateral chain in C2 (dimethyl carbomoilpyrrolidenethium) increases the activity versus gram negative bacteria (enterobacteria and pseudomonas) and moreover, may explain the reduction in the proconvulsive effect observed in imipenem/cilastatin. Meropenem has great bactericide power and has a very wide spectrum of activity depending on it low molecular weight and zwiterionic structure, stability versus almost all the clinically important beta-lactamases and high affinity for the PBPs. It covers gram positive aerobes (Staphylococcus aureus, coagulase negative staphylococci, streptococci including Streptococcus pneumoniae resistant to penicillin, Enterococcus faecalis, Rhodococcus equi, Listeria monocytogenes) and gram negative bacteria (enterobacteria, P. aeruginosa, Acinetobacter, Aeromonas, Plesiomonas, Vibrio, Haemophilus influenzae, Neisseria, Moraxella) and anaerobes (Bacteroides, Prevotella, Porphyromonas, Fusobacterium, Clostridium, Peptostreptococcus, and Propionibacterium acnes), being more active than imipenem versus gram negatives: P. aeruginosa (2-4-fold), enterobacteria (2-32-fold) and H. influenzae (4-8-fold) and less active versus the gram positives (enterococci, streptococci and staphylococci). Meropenem has no activity on Enterococcus faecium, S. aureus resistant to methycillin, Stenotrophomonas maltophilia and other genera producers of chromosomic methalo-beta-lactamases (carbapenemases). Resistance may be due to impermeability given the loss of the OprD porin (OprD2 in enterobacteria and P. aeruginosa) loss of different membrane proteins (Proteus mirabilis, Proteus rettgeri, Enterobacter cloacae, Enterobacter aerogenes), modifications of the PBPs (gram positive) and the production of carbapenemases (chromosomic methalo-beta-lactamases).

Bacteria, Aerobic↗

PubMed2004

Simple and rapid PCR method for identification of streptococcal species relevant to animal infections based on 23S rDNA sequence.

A PCR identification system targeting 23S rDNA sequences for the identification of eight streptococcal species relevant to animal infections (Streptococcus agalactiae, S. bovis, S. canis, S. dysgalactiae, S. equi, S. porcinus, S. suis and S. uberis) was developed. This system consists of two PCR reactions, A and B, in which seven and eight primers, respectively, are used simultaneously, and was designed so that each amplification product indicates a species by its size. A total of 111 cultures, including the type strain of eight species, could be successfully identified and differentiated as individual species, except for the cross reactivity between S. bovis and S. equinus. The developed PCR system can complete the identification procedure for eight streptococcal species through two tube reactions per isolate, and, therefore, might provide a rapid, simple and accurate diagnostic tool for veterinary laboratories.

Animals↗

PubMed1996

Analysis of genetic relationships among strains of groups A, C and G streptococci by random amplified polymorphic DNA analysis.

Random amplified polymorphic DNA (RAPD) analysis was evaluated for its capacity to distinguish species and strains within species of groups A, C and G streptococci. The 99 strains tested, previously typed by multilocus enzyme electrophoresis (MLEE), included 41 group A streptococci (Streptococcus pyogenes), 25 group G Streptococcus spp. (GGS), seven S. dysgalactiae, 11 S. equisimilis, four S. canis, three S. equi and eight S. zooepidemicus. The combined data obtained with three single primers distinguished 82 types. RAPD analysis provided taxonomic results that were in general agreement with previous species classification based on DNA-DNA homology and MLEE. The intraspecies typing efficiency of the technique was significantly improved by the parallel use of several primers. RAPD analysis had greater discriminatory power than MLEE for GAS and GGS. There was not total agreement between the two techniques as RAPD distinguished strains with identical electrophoretic types, whereas MLEE differentiated strains with identical PCR types. RAPD analysis did not distinguish all GAS strains with different biotypes and its already high discriminatory power was further enhanced by concomitant biotyping.

Animals↗

PubMed1990

Role of alpha 2-macroglobulin in phagocytosis of group A and C streptococci.

Binding of alpha 2-macroglobulin (alpha 2M) to streptococci and its effects on phagocytosis were investigated. Two types of streptococcal binding sites for alpha 2M were observed: Streptococcus pyogenes from human infections interacted only with native alpha 2M whereas S. dysgalactiae from bovine and S. equi from equine infections bound only a complex of alpha 2M with trypsin (alpha 2M-T). Preincubation of S. pyogenes with native alpha 2M substantially enhanced their phagocytosis by human polymorphonuclear neutrophils (PMN) whereas preincubation with alpha 2M-T was without any effect. On the other hand, incubation of S. dysgalactiae and S. equi with alpha 2M-T markedly reduced their phagocytosis by PMN from the respective host species. Native alpha 2M did not affect the phagocytosis of these streptococci. Digestion of the streptococcal binding sites for alpha 2M and alpha 2M-T pronase abolished the enhancement of phagocytosis of S. pyogenes by native alpha 2M as well as the inhibition of phagocytosis of S. dysgalactiae and S. equi by alpha 2M-T. Thus, binding of alpha 2M or its complexes appeared to play a role in streptococcal pathogenicity.

Animals↗

PubMed2003

In vitro antimicrobial activity of moxifloxacin compared to other quinolones against recent clinical bacterial isolates from hospitalized and community-based cancer patients.

The in vitro spectrum of moxifloxacin (a C-8-methoxyquinolone) was compared to that of ciprofloxacin and levofloxacin against 924 recent clinical isolates from cancer patients. Moxifloxacin was more active than the comparator agents against Gram-positive pathogens, with potent activity against Aerococcus spp., Listeria monocytogenes, Micrococcus spp., Rhodococcus equi, and Stomatococcus mucilaginous, methicillin-susceptible Staphylococcus spp., all beta hemolytic streptococci, viridans streptococci and Streptococcus pneumoniae. It also had good to moderate activity against Bacillus spp., Corynebacterium spp., Enterococcus faecalis, and methicillin-resistant staphylococci. Although ciprofloxacin was the most active agent tested against the Enterobacteriaceae, moxifloxacin inhibited the majority of these isolates at < or =2.0 microg/ml. Moxifloxacin was the least active of the three agents tested against Pseudomonas aeruginosa, but had significant activity against other non-fermentative Gram-negative bacilli including Acinetobacter spp., Flavobacterium spp., Pseudomonas spp. other than P. aeruginosa, and Stenotrophomonas maltophilia. The overall broad spectrum of moxifloxacin, and its availability for both oral and parenteral administration, warrants its evaluation for the prevention and treatment of infections in cancer patients.

Anti-Infective Agents↗

PubMed1997

Intracranial bacterial infections in patients with AIDS.

Nontuberculous, nonsyphilitic intracranial bacterial infections in HIV-positive individuals may be nonspecific presentations of unusual organisms, such as R. equi, B. henselae, Nocardia sp. or L. monocytogenes. In addition, more common organisms, such as Staphylococcus, Streptococcus, or Salmonella sp. may cause an unusually severe infection. In general, the imaging appearance of these bacterial infections is similar to that in immunocompetent individuals.

AIDS-Related Opportunistic Infections↗

PubMed1985

[Hyalurodinase activity of beta-hemolytic streptococci of the Lancefield group C].

A total of 110 strains of beta-hemolytic streptococci, belonging to serogroup C (Lancefield), isolated from horses (71 S. zooepidemicus, 27 S. equisimilis and 12 S. equi) as well as 5 reference strains were tested for their ability to produce hyaluronidase. The determinations were carried out in a culture test on agarose gel and in a liquid test system (turbidity test according to DiFerrante). The results of both methods used showed that the three Streptococcus species could be differentiated by the relative quantitative determination of hyaluronidase activity. S. equisimilis strains produce 5 to 10 times more hyaluronidase than those of S. zooepidemicus. The strains of S. equi did not show enzyme production. In addition parallel tests by determination of final N-acetyl-D-glucosamine groups and by turbidity test were done to confirm the hyaluronidase activity of S. equisimilis strains. The comparison of results (Fig. 3) obtained from these tests, showed a good correspondence as demonstrated by a correlation index of 0,93.

Animals↗

PubMed1995

Identification and typing of pyogenic streptococci by enzyme electrophoretic polymorphism.

Polyacrylamide-agarose gel electrophoresis was used to study polymorphism of lactate dehydrogenase (LDH), nucleoside phosphorylase (NSP), phosphoglucose isomerase (PGI), hydroxybutyrate dehydrogenase (HBD), adenylate kinase (ADK) and esterases of 44 strains of Streptococcus pyogenes, 25 group G streptococcal strains, 11 "S. equisimilis" strains, seven S. dysgalactiae strains, four S. canis strains, three S. equi strains and seven S. zooepidemicus strains. Analysis of LDH, NSP, PGI, HBD and ADK provided valuable interspecies differentiation, by showing that four groups of strains corresponded to the four known DNA homology groups. Esterases showed greater intraspecies variation than the other enzymes. The combined analysis of the six enzymes indicated 31 zymotypes among S. pyogenes, 14 in group G streptococci and 11 in "S. equisimilis" strains. This was shown to be an effective technique for typing pyogenic streptococci.

Adenylate Kinase↗

PubMed1991

Oral associated bacterial infection in horses: studies on the normal anaerobic flora from the pharyngeal tonsillar surface and its association with lower respiratory tract and paraoral infections.

Two hundred and seventy bacterial isolates were obtained from the pharyngeal tonsillar surface of 12 normal horses and 98 obligatory anaerobic bacteria were characterised. Of these, 57 isolates belonging to 7 genera (Peptostreptococcus (1); Eubacterium (9); Clostridium (6); Veillonella (6); Megasphera (1); Bacteroides (28); Fusobacterium (6)) were identified, and 16 of these were identified to species level (P. anaerobius (1); E. fossor (9); C. villosum (1); B. fragilis (1); B. tectum (2); B. heparinolyticus (2)). Three hundred and twenty isolates were obtained from 23 samples from horses with lower respiratory tract (LRT) or paraoral (PO) bacterial infections. Of the 143 bacteria selected for detailed characterisation, obligate anaerobes accounted for 100 isolates, facultative anaerobes for 42 isolates and obligate aerobes for one isolate. Phenotypic characterisation separated 99 of the isolates into 14 genera. Among the obligately anaerobic species, Gram-positive cocci including P. anaerobius comprised 25% of isolates, E. fossor 11% and other Gram-positive rods (excluding Clostridium sp.) 18% of isolates. The Gram-negative rods comprised B. fragilis 5%, B. heparinolyticus 5%, asaccharolytic pigmented Bacteroides 3% and other Bacteroides 13%, while a so-far unnamed species of Fusobacterium (7%), and Gram-negative corroding rods (3%) were isolated. Among the facultatively anaerobic isolates, S. equi subsp. zooepidemicus accounted for 31% of isolates, followed by Pasteurella spp. 19%, Escherichia coli 17%, Actinomyces spp. 9%, Streptococcus spp. 9%. Incidental facultative isolates were Enterococcus spp. 2%, Enterobacter cloaceae 2%, Actinobacillus spp. 2% and Gram-negative corroding rods 5%. On the basis of the similarities (as determined by DNA hybridization data and/or phenotypic characteristics) of some of the bacterial species (e.g. E. fossor and B. heparinolyticus) isolated from both the normal pharyngeal tonsillar surfaces and LRT and PO diseases of horses, it is considered that the most likely source of bacteria involved in these disease processes is flora from the oral cavity.

Animals↗

PubMed2006

Binding of porcine ficolin-alpha to lipopolysaccharides from Gram-negative bacteria and lipoteichoic acids from Gram-positive bacteria.

Protein(s) reactive with N-acetyl-D-glucosamine (GlcNAc) was isolated from porcine nonimmune serum. The molecular weight of the purified protein was found to be mainly 40 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. The N-terminal 10 amino acid sequence of the purified protein were found to be identical to that of porcine ficolin-alpha reported previously. In enzyme-linked immunosorbent assay, the purified protein was found to react with lipopolysaccharides (LPS) from different Gram-negative bacteria such as Esherichia coli, Salmonella typhimurium, Salmonella enteritidis, Salmonella abortus equi, Pseudomonas aeruginosa, Shigella flexeneri, and Serratia marcescens and with lipoteichoic acid (LTA) from Gram-positive bacteria such as Streptococcus sanguis, Bacillus subtilis, Streptococcus pyogenes, and Staphylococcus aureus. The purified protein also reacted with E. coli O26 isolated from food poisoning and bovine feces and heat-treated Gram-positive bacteria such as S. aureus, B. cereus, B. subtilis, Enterococcus faecium, and Corynebacterum bovis. On the other hand, porcine IgG isolated from nonimmune serum showed different reactivity with these LPS, LTA, and heat-treated bacterial cells. From the present findings, purified porcine serum protein reactive with GlcNAc is concluded to be ficolin-alpha playing an important role(s) in innate immunity against microbial infection with Gram-positive and -negative bacteria.

Amino Acid Sequence↗

PubMed2004

In vitro antimicrobial activity of gatifloxacin compared with other quinolones against clinical isolates from cancer patients.

Owing to the predominance of gram-positive pathogens in neutropenic cancer patients, newer generation quinolones with an expanded gram-positive spectrum and enhanced potency, may have a role to play for prophylaxis and/or empiric therapy in such patients. The in vitro activity of gatifloxacin was compared with that of ciprofloxacin, levofloxacin and trovafloxacin against 848 recent clinical isolates from cancer patients. Against gram-positive organisms, gatifloxacin was the most active agent tested inhibiting all Aerococcus, Listeria monocytogens, Micrococcus, Stomatococcus mucilaginous, Bacillus, and Rhodococcus equi strains at < or =2 mg/l, its designated susceptibility breakpoint. It was also very active against methicillin-susceptible staphylococci and Streptococcus spp. (including penicillin nonsusceptible Streptococcus pneumoniae and viridans streptococci). It had moderate activity against methicillin-resistant staphylococci and Enterococcus faecalis, inhibiting 68-80% of these strains at < or =2 mg/l. Gatifloxacin also had good activity against the Enterobacteriaceae (although ciprofloxacin was more potent) inhibiting >95% of isolates at < or =1 mg/l. Nonfermentative gram-negative organisms were less susceptible to all 4 agents. Gatifloxacin was very active against Acinetobacter lwoffi (MIC100 0.12 mg/l) and had moderate activity against Acinetobacter baumanii, Chryseobacterium spp., Stenotrophomonas maltophilia, Pseudomonas aeruginosa and other Pseudomonas species. Alcaligenes xylosoxidans strains were relatively resistant to all 4 agents.

Anti-Bacterial Agents↗

PubMed1993

Association of microbiologic flora with clinical, endoscopic, and pulmonary cytologic findings in foals with distal respiratory tract infection.

Undifferentiated distal respiratory tract disease (nasal discharge, cough, pneumonia) in foals (1 to 8 months old) is a burdensome economic problem on breeding farms; yet, the infective agents associated with these episodes have not been well described. Possible causes of these episodes of illness were investigated by culturing specimens of proximal and distal airways of clinically diseased foals (n = 101), prior to any treatment, for aerobic and anaerobic bacteria and viruses (rhinoviruses, equine arteritis virus, equine herpesvirus subtype 1 [EHV-1], influenza virus, and adenovirus). Pairs of sera (n = 47) were examined for antibodies to influenza A virus, equine subtypes 1 and 2, EHV-1, and adenovirus antigens, and sera obtained from foals during acute infection were examined for antibodies (by agar gel immunodiffusion [AGID]) to equi factor antigens of Rhodococcus equi. Viruses were not isolated from the proximal (swab) or distal (bronchial lavage) airway specimens in foals, and only 2 of 47 randomly selected foals seroconverted to EHV-1. Serotiters to the other viruses were low and frequently decreasing between samples, which was compatible with maternally derived antibody. Streptococcus zooepidemicus was the predominant isolate from bronchial lavage specimens (88/101 cases), accompanied by alpha-hemolytic streptococci (8 cases), Bordetella bronchiseptica (13 cases), Staphylococcus epidermidis (9 cases), and other organisms in lesser frequency. Only Str zooepidemicus was recovered significantly (P < 0.05) more often in cases than in controls. The AGID test was found useful to detect foals with presumed exposure to R equi, but positive tests results did not correspond well with bacterial culture results; positive AGID results were recorded in 34% of culture-negative foals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Biochemical differences among human and animal streptococci of Lancefield group C or group G.

Pyogenic streptococci of Lancefield group C or group G from human or animal sources were examined with a view to increasing the number of diagnostic tests useful for their differentiation. Human strains of group G produced L-prolyl-L-arginine aminopeptidase but isolates of Streptococcus equisimilis (group C) did not. Tests for alpha-L-glutamate aminopeptidase together with fermentation of glycogen or sorbitol distinguished S. dysgalactiae from strains of S. equisimilis isolated from animals. It was confirmed that fermentation tests were helpful in the study of S. equi and S. zooepidemicus and that enzyme reactions helped distinguish between S. canis and the human strains of group G.

Aminopeptidases↗