Distribution and incidence of viridans streptococcal species in routine clinical specimens

Sexual behavior shapes male genitourinary microbiome composition

The origin, composition, and significance of the distal male urethral microbiome are unclear, but vaginal microbiome dysbiosis is linked to new sex partners and several urogynecological syndromes. We characterized 110 urethral specimens from men without urethral symptoms, infections, or inflammation using shotgun metagenomics. Most urethral specimens contain characteristic lactic acid bacteria and Corynebacterium spp. In contrast, several bacteria associated with vaginal dysbiosis were present only in specimens from men who reported vaginal intercourse. Sexual behavior, but not other evaluated behavioral, demographic, or clinical variables, strongly associated with inter-specimen variance in urethral microbiome composition. Thus, the male urethra supports a simple core microbiome that is established independent of sexual exposures but can be re-shaped by vaginal sex. Overall, the results suggest that urogenital microbiology and sexual behavior are inexorably intertwined, and show that the male urethra harbors female urogenital pathobionts.

A Case of Urinary Sepsis Secondary to Streptococcus sanguinis

We report a case of a 71-year-old male with a history of BPH who presented with flank pain, fever, chills, abdominal pain, and nausea. He had a dental cleaning 1 month prior to admission and flosses daily. Laboratory data revealed both urine and blood cultures to be positive for streptococcus sanguinis. Computed tomography revealed a 10 mm right ureteral stone, and an ultrasound demonstrated moderate right hydronephrosis. He underwent an ureteroscopy with stent placement. A transesophageal echocardiogram was negative for endocarditis. He completed 2 weeks of IV ceftriaxone and made a complete recovery.

Septic arthritis of the pubic symphysis caused by Streptococcus mitis

Septic arthritis of the pubic symphisis is distinguished from osteitis pubis by positive cultures. The symptoms, physical examination and laboratory findings of these two conditions are comparable. We present a case of 57-year-old woman with septic arthritis of pubic symphisis caused by Streptococcus mitis, a commensal oral flora that belongs to viridans group streptococci, which normally reside in the oral cavity, the gastrointestinal and the urogenital tract.

Use of rapid carbohydrate utilisation test for identifying "Streptococcus milleri group"

A short series of biochemical and serological tests were developed for the rapid presumptive identification of "Streptococcus milleri group" isolates. One hundred and seventy seven streptococcal isolates were recovered from the mouths of 10 out of 12 healthy adult volunteers by use of a simple sampling procedure and a single selective medium. In all, 127 oral "S milleri group" isolates were identified by biochemical and serological tests, confirming the indigenous nature of these streptococci in the mouth. Most (70.1%) of "S milleri group" isolates were non-haemolytic, 26% were alpha-haemolytic, and 3.9% beta-haemolytic. Fifty four (42.5%) were serologically typable, of which 46 were Lancefield group F, suggesting that the mouth is an important source of Lancefield group F streptococci. A collection of group F streptococci from a range of sources was indistinguishable from a collection of oral "S milleri group" isolates on the basis of the tests used, supporting the general synonymity of group F streptococcus with the broader "S milleri group". The battery of tests was cheap and simple to perform, and was capable of identifying "S milleri group" isolates from a range of sources, including variants with wide sugar fermentation patterns.

Clinical and bacterial features of infections caused by Streptococcus milleri

The clinical and bacteriological features of 51 infections due to Streptococcus milleri observed in 43 patients over a 2-year period were reviewed. Clinical syndromes included bacteremia in 6 cases, endocarditis in 4 cases, cellulitis and subcutaneous abscesses in 8 cases, pleural empyema in 8 cases, brain abscesses in 5 cases, abdominal infections in 5 cases, and other miscellaneous infections in 15 cases. An underlying condition was associated with infection in 33/43 patients (77%). S. milleri was the only pathogen isolated in 19 patients (44%). All strains of S. milleri were susceptible to penicillin. Surgery was combined with antimicrobial therapy in 27 (63%) patients. Nine patients died during hospitalization, and death was directly related to S. milleri infection in 4 patients (9%). These results confirm that S. milleri frequently causes serious suppurative infections and that species identification is a clinically useful procedure.

Vancomycin-resistant gram-positive bacteria isolated from human sources

Recent reports of infections with vancomycin-resistant gram-positive bacteria prompted us to study vancomycin-resistant isolates from human sources to characterize the types of bacteria displaying this phenotype. Thirty-six vancomycin-resistant gram-positive isolates, 14 from clinical specimens and 22 from stool samples, were identified. These isolates were tentatively identified as Lactobacillus spp. (25 strains), Leuconostoc spp. (6 strains), and Pediococcus spp. (3 strains) on the basis of morphology and physiological tests. Two isolates of indeterminate morphology could not be unambiguously assigned to a genus. Four isolates of vancomycin-resistant lactobacilli from normally sterile body sites were considered to be clinically significant. Vancomycin-resistant gram-positive bacteria may represent an emerging class of nosocomial pathogens. Better methods for distinguishing the various genera in the clinical microbiology laboratory are needed.

Association of viridans group streptococci from pregnant women with bacterial vaginosis and upper genital tract infection

The prevalence and role of viridans group streptococci in the female genital tract have not been well described. In this study of 482 pregnant women, 147 (30%) were culture positive for viridans group streptococci. Of 392 women with predominant Lactobacillus morphotypes by Gram stain (normal), 110 (28%) were colonized with viridans group streptococci, compared with 37 (41%) of 90 women with bacterial vaginosis (BV) (P = 0.02). To determine whether any species were associated with BV, 177 consecutively isolated viridans group streptococci from the vagina were identified to the species level by using the Facklam scheme. The most frequently isolated species from the vagina was Streptococcus intermedius (13%), followed by Streptococcus acidominimus (6%), Streptococcus constellatus (5%), Streptococcus sanguis II (4%), Streptococcus mitis (2%), Streptococcus salivarius (2%), Streptococcus morbillorum (2%), Streptococcus sanguis I (1%), Streptococcus mutans (0.2%), and Streptococcus uberis (0.2%) with an average of 1.2 species per woman. The distribution of the species among women with BV compared with normal women was not significantly different, with the exception of two species which were associated with BV: S. acidominimus (18% versus 3%, P less than 0.001) and S. morbillorum (6% versus 0.7%, P = 0.005). Amniotic fluid and placenta cultures yielded 54 isolates: S. sanguis II (13 isolates), S. acidominimus (9 isolates), S. intermedius (10 isolates), S. constellatus (3 isolates), S. mitis (4 isolates), S. sanguis I (4 isolates), S. morbillorum (5 isolates), S. mutans (2 isolates), S. uberis (1 isolate), mannitol-positive S. intermedius (1 isolate), and 2 isolates which were not classified. The distribution of species isolated from the upper genital tract was not a reflection of the distribution in the lower genital tract. Dextran-producing species of viridans group streptococci may have a greater pathogenic potential in the placenta than the non-dextran-producing species.

Streptococcus anginosus ("Streptococcus milleri"): the unrecognized pathogen

"Streptococcus milleri" is an unofficial name that has been applied to a group of streptococci which, although basically similar, show various hemolytic, serological, and physiological characteristics. The species name Streptococcus anginosus has recently been recognized as the approved name for these organisms. Streptococci known as "S. milleri" have been implicated as etiologic agents in a variety of serious purulent infections, but because of their heterogeneous characteristics, these organisms may be unrecognized or misidentified by clinical laboratorians. This review describes the bacteriological aspects of organisms known as "S. milleri," their clinical significance, and the problems encountered with their identification in the clinical laboratory.

Hydrolytic enzymes of "Streptococcus milleri"

Seventy-two isolates classified as "Streptococcus milleri" were examined for the presence of various hydrolytic enzymes. While no protein or lipid-degrading activities were demonstrated, some isolates showed DNase and mucopolysaccharide-degrading activities. Beta-hemolytic isolates were more likely to produce these enzymes than were nonhemolytic strains. Isolates of one "S. milleri" biotype (mannitol fermentation positive) were uniformly devoid of all enzyme activities tested.

Isolation of Streptococcus milleri from clinical specimens

During a period of 26 months, 80 strains of Streptococcus milleri were isolated from 80 patients with clinical evidence of infection. More than a third of the isolates were from lesions related to the gastro-intestinal tract and a quarter from abscesses of various other sites. The haemolytic activity and group antigenic profile of these isolates are discussed. In addition, the clinical significance of S. milleri isolated from various sites is evaluated.

Clinical significance of Streptococcus milleri

The clinical features of infection in patients from whom Streptococcus milleri was isolated were analysed in an attempt to determine the clinical significance of this organism. During a four-year period Streptococcus milleri was isolated from 232 hospitalized patients. In 44 patients Streptococcus milleri was isolated in pure culture, in 45 patients together with obligate anaerobes, and in 143 patients together with aerobes with or without anaerobes. The 82 patients in whom isolation of Streptococcus milleri was considered significant had the following infections: bacteremia (8 patients), brain abscess (2), pleural empyema (9), lung abscess (1), maxillary sinusitis (7), intra-abdominal abscess (53), infection of pacemaker (1) and infection of vascular graft (1). The 150 patients in whom isolation of Streptococcus milleri was considered of questionable significance had the following: upper respiratory tract infection (12 patients), lower respiratory tract infection (6), acute cholecystitis (8), soft tissue abscess, cellulitis and surgical wound infections (83), bone and joint infections (14), genital infection (25) and miscellaneous infections (2). The overall incidence of infection with Streptococcus milleri was five cases per 1000 admissions. The study showed that Streptococcus milleri is of clinical significance not only in suppurative infections, as previously reported, but also in acute maxillary sinusitis and infection of implant material.

Evaluation of rapid identification of gram-positive cocci in positive blood cultures by use of the AutoMicrobic system Gram-Positive Identification Card

Because rapid identification of gram-positive organisms from blood cultures may provide valuable information for patient care and because the AutoMicrobic system Gram-Positive Identification (AMS-GPI) Card (Vitek Systems, Inc., Hazelwood, Mo.) is designed for the identification of these organisms in 4 to 13 h, we designed this study to evaluate the performance of the AMS-GPI Card in the direct identification of gram-positive organisms upon detection of growth in blood culture bottles. We compared direct identification by the AMS-GPI Card with the final AMS-GPI Card identification and with our standard identification methods. We evaluated 51 gram-positive organisms from clinical blood cultures as well as 49 simulated blood cultures. The isolates included Streptococcus pneumoniae (17), Streptococcus pyogenes (13), group D enterococci (12), Streptococcus agalactiae (11), viridans streptococci (10), coagulase-negative staphylococci (21), Staphylococcus aureus (15), and Listeria monocytogenes (1). The AMS-GPI Card identified all of the group D enterococci, viridans streptococci, and coagulase-negative staphylococci and all but one each of the Streptococcus pyogenes and Streptococcus agalactiae isolates. L. monocytogenes was also correctly identified. However, the AMS-GPI Card identified only 12 of 17 Streptococcus pneumoniae and 9 of 15 Staphylococcus aureus isolates by direct inoculation. We therefore conclude that the results of direct identification of gram-positive organisms by the AMS-GPI Card may be used cautiously for rapid direct identification of gram-positive organisms from positive blood cultures.