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PubMed2000

The virulence of mixed infection with Streptococcus constellatus and Fusobacterium nucleatum in a murine orofacial infection model.

Orofacial infections are usually polymicrobial, and it is the microbial interactions of pathogenic species that cause tissue destruction. In this study, the microbial interaction between Streptococcus constellatus and Fusobacterium nucleatum was characterized using a murine orofacial infection model. A mixture of viable S. constellatus and F. nucleatum cells (both 2 x 10(8) CFU/mouse) was injected into the submandible; as a result, all of the test mice died. In contrast, none of the experimental animals monoinjected with either S. constellatus or F. nucleatum died (P<0.001), indicating that the synergism between the two resulted in the virulence. When a mixture of viable S. constellatus cells and a culture filtrate of F. nucleatum was tested, lethality and the bacterial cell count per lesion were significantly enhanced as compared with monoinjections (P<0.02). However, the virulence of F. nucleatum was not enhanced by infection of a culture filtrate of S. constellatus. The enhancement of virulence was observed even when viable S. constellatus cells and the culture filtrate of F. nucleatum were injected at separate sites. Heat treatment of the culture filtrate of F. nucleatum did not affect the enhancement. These results indicate that a heat-stable substance(s) produced by F. nucleatum contributes to the microbial synergy of S. constellatus and F. nucleatum in orofacial infections.

Abscess↗
PubMed1977

[Risk of neonatal Streptococcus B infection].

23 cases of contamination with streptococcus group B have been seen after premature rupture of the membranes. Mothers and fetuses have been affected. The systematic study of swabs or liquor or cervical discharge carried out on the mother since the time her membranes had ruptured show that in 74 per cent of cases studied contamination existed within the first 24 hours. Giving antibiotics to the mother before delivery gave very variable results. These multiple tests, before and around the time of birth, made it possible to detect the children at risk of infection and to start antibiotic therapy with a narrow spectrum antibiotic of the type Penicillin G. The clinical progress of these children, which is usually favourable, gives no reason for postponing prophylactic cover antibiotic treatment when the membranes have ruptured prematurely.

Agglutination Tests↗
PubMed2006

Evaluation of a nested PCR test and bacterial culture of swabs from the nasal passages and from abscesses in relation to diagnosis of Streptococcus equi infection (strangles).

REASONS FOR PERFORMING STUDY: Streptococcus equi is the cause of strangles in horses. To improve diagnostic sensitivity, development and evaluation of DNA-based methods are necessary. OBJECTIVES: To evaluate diagnostic methods and observe the pattern of bacterial shedding during natural outbreaks. METHODS: Two herds with natural outbreaks of strangles were visited over a period of 15 weeks and 323 samples originating from 35 horses investigated. The diagnostic use of a nested PCR test was evaluated using a collection of 165 isolates of Lancefield group C streptococci (species specificity) and swabs from nasal passages or from abscesses from horses infected with S. equi (diagnostic sensitivity). RESULTS: All 45 S. equi isolates tested positive in the nested PCR, whereas no amplicon was formed when testing the other 120 Lancefield group C isolates. A total of 43 samples were collected from 11 horses showing clinical signs of strangles during the study period. The diagnostic sensitivity for PCR test was 45% and 80% for samples from the nasal passages and abscesses, respectively; the corresponding diagnostic sensitivity for cultivation was 18% and 20%. The diagnostic sensitivity was significantly higher for PCR than for bacterial cultivation. Furthermore, the shedding of S. equi in 2 infected horse populations was evaluated. An intermittent shedding period of S. equi of up to 15 weeks was recorded in this part of the study. It was also shown that shedding of S. equi occurred both from horses with and without clinical signs. CONCLUSIONS AND POTENTIAL RELEVANCE: The nested PCR test represents a species-specific and -sensitive method for diagnosis of S. equi from clinical samples. It may, however, be desirable in future to develop detection methods with high diagnostic sensitivity and specificity without the potential problems inherent in nested PCR.

Abscess↗
PubMed2007

Human C-reactive protein protects mice from Streptococcus pneumoniae infection without binding to pneumococcal C-polysaccharide.

Human C-reactive protein (CRP) protects mice from lethality after infection with virulent Streptococcus pneumoniae type 3. For CRP-mediated protection, the complement system is required; however, the role of complement activation by CRP in the protection is not defined. Based on the in vitro properties of CRP, it has been assumed that protection of mice begins with the binding of CRP to pneumococcal C-polysaccharide on S. pneumoniae and subsequent activation of the mouse complement system. In this study, we explored the mechanism of CRP-mediated protection by utilizing two CRP mutants, F66A and F66A/E81A. Both mutants, unlike wild-type CRP, do not bind live virulent S. pneumoniae. We found that passively administered mutant CRP protected mice from infection as effectively as the wild-type CRP did. Infected mice injected with wild-type CRP or with mutant CRP lived longer and had lower mortality than mice that did not receive CRP. Extended survival was caused by the persistence of reduced bacteremia in mice treated with any CRP. We conclude that the CRP-mediated decrease in bacteremia and the resulting protection of mice are independent of an interaction between CRP and the pathogen and therefore are independent of the ability of CRP to activate mouse complement. It has been shown previously that the Fcgamma receptors also do not contribute to such CRP-mediated protection. Combined data lead to the speculation that CRP acts on the effector cells of the immune system to enhance cell-mediated cytotoxicity and suggest investigation into the possibility of using CRP-loaded APC-based strategy to treat microbial infections.

Animals↗
PubMed1981

Outbreak of Streptococcus pyogenes infections in a geriatric hospital and control by mass treatment.

Two outbreaks of Streptococcus pyogenes infection occurred in a geriatric hospital, the first involving one ward only, the second a few weeks later, affecting two. Altogether 17 patients and 6 members of staff were carriers or were infected. All strains were indistinguishable.Extensive investigation of the environment and screening of 120 staff and patients did not reveal a common source. The usual methods of isolation and treatment of cases or carriers and swabbing of contacts failed to stop the outbreak, but 'mass treatment' of all 32 patients in those wards was successful.

Aged↗
PubMed1983

Correlation of level and duration of Streptococcus mutans infection with incidence of dental caries.

The caries incidence at various levels of Streptococcus mutans infection was analyzed in a control group and a test group. In the control group, the incidence of caries and the duration of S. mutans infection were significantly correlated. In the test group, the S. mutans infection was suppressed by antimicrobial measures when the number of S. mutans exceeded 250 X 10(3) CFU per ml of saliva. The results illustrate that the level and duration of the S. mutans infection are strongly correlated to the incidence of caries. The findings support the concept of S. mutans as a key cariogenic microorganism and illustrate the value of antimicrobial treatment in the prevention of caries.

Adolescent↗
PubMed2005

[Anlysis on features of dead cases with human Streptococcus suis infections].

OBJECTIVE: To describe the clinical and epidemiological features of dead cases with human Streptococcus suis infections, and to find the target population for preventing death and the related indicators. METHODS: Epidemiological investigation on human Streptococcus suis infections was implemented used unified questionnaires. Analysis on dead cases and survival cases (as contrast) was done. RESULTS: The population with highest fatality rate was in 40-49 age group. 97.37% of dead cases had toxic shock syndrome. The mean interval from onset to admission was 0.76 days, and the mean course was 2.11 days. The progression among dead cases was faster than that among survival cases. Chief clinical manifestations of dead cases that are more frequent than survival cases are purpura (73.68%), diarrhea (50.0%), dyspnea (21.05%), conjunctival congestion (34.21%), etc. Renal impairment and liver involvement in dead cases were more significant than that in survival cases. No significant difference between mean incubation period, exposure rates of main risk factors in dead cases and in survival cases was found. CONCLUSION: Preventing toxic shock syndrome might reduce the fatality rate. The target population for preventing death is aged > or = 40. Liver function and renal function testing might be indicators for monitoring the progression of human Streptococcus suis infections.

Adult↗
PubMed1997

Development and efficacy of a vaccine against Streptococcus iniae infection in farmed rainbow trout.

Formalin killed bacteria were used as a vaccine against Streptococcus iniae infections in farmed rainbow trout. A single intraperitoneal injection of this vaccine in trout resulted in specific antibody production detectable for 6 months. Trout vaccinated at 50 g were protected under laboratory (experimental disease) and field conditions (natural disease) for at least 4 months against S. iniae infection. Passive transfer of S. iniae specific antibodies conferred protection. Under field conditions, mortality of non vaccinated trout exceeded 50%, whereas mortality of vaccinated trout did not reach 5%. In addition, vaccinated trout under field conditions gained 20% weight when compared with non vaccinated fish.

Agglutination Tests↗
PubMed1994

Epidemiologic and immunologic characteristics of Streptococcus equi infection in foals.

A 2-phase study was performed to characterize the effects of Streptococcus equi infection in unexposed and previously exposed foals. In phase I, 22 weanling foals involved in a naturally occurring S equi epizootic were studied, along with a comparison group of 11 unexposed foals, matched for age, sex, and breed. Six months later (phase II), an epizootic was experimentally induced in previously exposed and unexposed foals from phase I. The prevalence and duration of clinical signs, the relative risk of developing disease, bacteriologic culture results, hematologic responses, and mucosal and serum immunologic responses were determined. Disease protection in phase-I and -II foals was associated with high values for serum S equi M protein-specific IgG at the onset of the epizootic (P < 0.02 for phase 1 and P < 0.01 for phase II), and with a rapid (within 2 weeks of exposure) mucosal S equi M protein-specific IgG response (P < 0.05 for phase I and P = 0.01 for phase II).

Analysis of Variance↗
PubMed1993

An outbreak of serotype 1 Streptococcus pneumoniae infection in central Australia.

An outbreak of serotype 1 Streptococcus pneumoniae infection involving both adults and children occurred in central Australia during the winter months of 1991. Eighteen patients, mainly Aboriginal men, presented with culture-positive serotype 1 bacteraemic pneumonia. In this group, 11 of 12 adults for whom medical records were available were alcohol dependent. Thirteen children who were separately studied were hospitalised with acute lower respiratory tract infection: none had bacteraemia but all had upper airway colonisation by type 1 pneumococci. Antibiotics taken by 8 of the 13 children before admission to hospital may have compromised the isolation of type 1 pneumococci from blood cultures. Since the availability of antibiotics, epidemic pneumococcal infection is infrequent and has not been reported in Australia. In three outbreaks of type 1 disease recorded elsewhere crowding and alcoholism were identified as contributory factors. In the 16 month period before this outbreak none of 162 strains of pneumococci isolated from blood (32 strains) and nasopharyngeal secretions (130 strains) from Aborigines with acute lower respiratory tract infection and meningitis in the Alice Springs region were serotype 1 organisms.

Adult↗
PubMedDate not supplied

Streptococcus mitis infection in newborns.

Although neonatal infections caused by Streptococcus viridans have been suggested to be less severe than those caused by classic neonatal pathogens, little is known about neonatal infections caused by specific species within this group of bacteria. We report six infants who had S. mitis isolated from blood culture. All were infected at < or = 3 days of age; five of the mothers had perinatal risk factors for neonatal sepsis. Five infants were preterm and three had birth weights < or = 2500 gm. Hematologic abnormalities were common. Two died as a result of the infection. Antibiotic susceptibility testing of four isolates revealed resistance to penicillin and ampicillin in three and resistance to gentamicin in two. In vivo resistance was not observed. S. mitis is not part of normal skin flora, should not be assumed to be a contaminant, and can cause severe neonatal disease. If S. mitis or S. viridans are recovered from a normally sterile body site and the patient fails to improve with penicillin therapy, it seems prudent to switch to vancomycin until susceptibility results are available.

Anti-Bacterial Agents↗
PubMed1991

Hyperendemic Streptococcus pyogenes infection despite prophylaxis with penicillin G benzathine.

BACKGROUND: In closely confined populations, in which epidemics of Streptococcus pyogenes infection are common, penicillin G benzathine has long been used prophylactically to reduce morbidity from this pathogen. We report on our investigations of the effectiveness of penicillin G benzathine prophylaxis at a military recruit camp. METHODS: We prospectively studied the rates of pharyngeal colonization and infection by S. pyogenes among 736 male U.S. Marine Corps recruits from January through March 1989. Throat swabs for culture, clinical data, and questionnaire data were obtained during six examinations at intervals of two weeks. Serum samples obtained before training, after training, and from acutely ill recruits were analyzed with use of an antistreptolysin O microtitration technique. RESULTS: Although 93 percent of the recruits received prophylaxis with two intramuscular injections of 1.2 million units of penicillin G benzathine each (administered 30 to 39 days apart), 33 percent of the recruits were colonized by S. pyogenes, and 42 percent had infection (as defined by a two-dilution increase in the antistreptolysin O titer). Thirty-seven percent of 265 recruits who reported a sore throat and were infected with S. pyogenes did not seek medical attention. The recruits who were allergic to penicillin (7 percent of the total), who received no prophylaxis, were more likely to be colonized; an increased risk of colonization and infection among the nonallergic recruits was associated with the presence of a higher percentage of allergic recruits in the platoon. After the study was completed, all recruits who were allergic to penicillin were prescribed 250 mg of oral erythromycin twice daily (a total daily dose of 500 mg) for 60 days. Subsequently, the average weekly rate of clinically evident S. pyogenes pharyngitis fell by more than 75 percent. CONCLUSIONS: If the prevention of S. pyogenes infection is to be effective in closely confined populations such as military recruits, prophylactic antibiotics must be administered to all members of the population. Exempting those who are allergic to penicillin may create a bacterial reservoir from which infection can be transmitted to nonallergic members of the population.

Drug Hypersensitivity↗
PubMed1999

Red drum Sciaenops ocellatus mortalities associated with Streptococcus iniae infection.

We isolated for the first time Streptococcus iniae strains associated with diseased marine fish. Diseased red drum Sciaenops ocellatus were lethargic, and presented external signs (exophthalmia and loss of orientation) resembling those of freshwater fish infected by S. iniae. Skin lesions, extending to a necrotizing myositis, were typical of S. iniae infection of red drum. Histopathological findings indicate that S. iniae infection in red drum produces a chronic disease with systemic involvement characterized by multiple necrotic foci. Molecular epidemiology (RFLP [restriction fragment length polymorphism] ribotyping) revealed that 2 different ribotypes were involved in a single outbreak. The first is the EcoRI 'Israeli' trout and tilapine ribotype (Hind III type a strains), while the second is the EcoRI 'American' ribotype (Hind III type b strains), typical of tilapines farmed in Texas and Idaho.

Animals↗
PubMed1989

Effect of a bacteriocin-producing strain of Streptococcus sobrinus on infection and establishment of Streptococcus mutans on tooth surfaces in rats.

The effect of bacteriocin produced by Streptococcus sobrinus MT6223 on infection and establishment of Streptococcus mutans MT6222 was studied in specific pathogen-free rats. These strains were isolated from a carious lesion of a single subject. S. mutans MT6222 was found to be susceptible to the growth inhibitory action of S. sobrinus MT6223. When simultaneously inoculated into the oral cavity of rats, even a small inoculum (10(5) CFU) of S. sobrinus MT6223 completely inhibited colonization of S. mutans MT6222 on the tooth surface. Also, S. sobrinus MT6223 eliminated S. mutans MT6222 when MT6223 (10(8) CFU) was inoculated 2 days after the inoculation of 10(8) CFU cells of MT6222. Similar results were obtained in dental plaque samples from the tooth surface and the fissures of the upper molars at the end of the experiment. However, when S. sobrinus MT6223 (10(8) CFU) was inoculated 2 weeks after the inoculation of S. mutans MT6222 (10(8) CFU), MT6223 coexisted with MT6222. However, the plaque samples showed that MT6223 inhibited the establishment of MT6222 on smooth surfaces, but not in fissures. In addition, MT6223 protected against subsequent infection with MT6222. However, a nonbacteriocinogenic mutant of S. sobrinus MT6223 did not inhibit the infection and establishment of S. mutans MT6222.

Animals↗
PubMed2001

Streptococcus milleri infection.

We report three cases of flexor sheath infection due to Streptococcus milleri in two patients. Soft tissue damage was extensive despite surgical debridement and appropriate antibiotic therapy. One patient had two digits amputated and the other had the affected digit amputated at the level of the proximal interphalangeal joint. These cases illustrate the potential pathogenicity of a bacterium which is often regarded as a commensal.

Amputation, Surgical↗
PubMed1990

Phenytoin-induced gingival overgrowth in rats infected with Streptococcus sobrinus 6715.

Inbred Fischer rats were fed a high sucrose diet (No. 2000) containing phenytoin (5,5-diphenyl-hydantoin) for 52 days, which produced serum and salivary PHT levels of 13-14 and 2.6-2.7 micrograms/ml, respectively. Gingival overgrowth was induced in the molar region of all PHT-treated rats but was more severe in Streptococcus sobrinus 6715-infected rats than in non-infected rats, which had lower plaque scores. No significant overgrowth was found in rats infected with Strep. sobrinus and fed the same diet without PHT. Thus dental plaque accumulation enhanced, but was not essential for the development of the PHT-induced gingival overgrowth. Histological examination showed that the density of fibroblasts and connective tissue fibres was similar in all groups. This experimental model could serve as a useful means of understanding the pathogenesis of PHT-induced gingival overgrowth.

Animals↗
PubMed1995

Streptococcus suis infection in Hong Kong.

Twenty-five patients were admitted to two hospitals in Hong Kong for Streptococcus suis infection between 1984 and 1993. Among them, 15 (60%) had an occupational exposure to pigs or pork, and four had a clear history of skin injury up to 16 days before admission. Examination of the cerebrospinal fluid of 21 patients confirmed the presence of meningitis in every case; the remaining four patients who did not have lumbar punctures had each presented with arthritis, bronchopneumonia, endocarditis and pyrexia without neck stiffness. The only fatality was a patient admitted in septicaemic shock with evidence of meningitis and disseminated intravascular coagulation. Of the 24 survivors, 16 (67%) acquired varying degrees of hearing loss as a result of meningitic involvement. All the isolates of S. suis were sensitive to penicillin or ampicillin, which was used alone or in combination with other antibiotics for every patient. Two patients had a relapse of symptoms when penicillin was stopped, but were successfully treated after the antibiotic was resumed for a total of 6 weeks. Over 100 cases of S. suis infection have been described previously, with a geographic distribution heavily biased towards Northern Europe and Southeast Asia. Lack of awareness of this unique zoonosis may be a reason why it is not diagnosed more readily elsewhere.

Adult↗