Once a day IV/IM cephalosporin with activity against almost all strains of streptococci.
Active against most streptococci, though lower bioavailability and frequent dosing make it a choice for less serious infections.
Resistance not uncommon for many species.
Available in both PO and IV forms. Well tolerated, but high incidence of C. difficile associated colitis. Not reliably active against viridans Streptococci and GBS.
Resistance not uncommon for many species.
May add for synergy in setting of endocarditis, serious bacteremia or if PCN MIC > 0.1.
Preferred therapy for susceptible strains of streptococci.
Active against nearly all strains of streptococci. Must be given IV. Usually only used in settings of PCN allergy.
Emergence of resistance on therapy has been described for viridans Streptococci.
Comment: Endocarditis treatment recommendations are based upon this document.
Comment: Far-reaching, comprenhensive review of skin and soft tissue infections, including those caused by beta-hemolytic Streptococci (with treatment recommendations as noted herein) as well as more common pathogens such as S. pyogenes and S. aureus
Comment: Osteomyelitis treatment recommendations are based upon this document.
Comment: Letter describing two seemingly unrelated clinical cases of vancomycin resistance to GBS. Both isolates were identified as vancomycin-nonsusceptible by local and state health authorities.
Comment: This work describes experimental models demonstrating the emergence of high-level daptomycin resistance upon exposure to daptomycin among viridans Streptococci isolates initially found to be susceptible to daptomycin. The addition of low-dose gentamicin prevented the emergence of daptomycin resistance in 91% of rabbits in their model.
Comment: Use of at least four hours of antimicrobial prophylaxis with either penicillin or ampicillin was 86-91% effective in preventing early-onset neonatal GBS disease. Use of clindamycin was significantly less effective, highlighting the need to use cefazolin, not clindamycin, for pregnant women without a history of anaphylaxis or urticaria upon exposure to penicillins.
Comment: Molecular testing to detect genital tract GBS colonization has been extensively studied, with excellent sensitivity and specificity. This analysis found such testing to be associated with lower rates of antibiotic administration when compared with convential culture-based diagnostics at 34-38 weeks gestation. Use of molecular diagnostics may lower rates of needless antibiotic administration (and its associated sequelae) at the cost of the greater expense of real-time PCR testing.
Nice epidemiologic summary of incidence rates of meningitis due to Pneumococcus, Meningococcus, L. monocytogenes, H. influenza, and S. agalactiae based upon laboratory- and population-based surveillance data. Rates of meningitis due to all pathogens save S. agalactiae decreased significantly over the interval.
Interesting discussion of the pathogenic mechanisms by which (a) GI tract colonization with S. gallolyticus subsp. gallolyticus might increase among persons with colorectal cancer, and (b) increased incidence rates of endocarditis caused by this pathogen among these patients might be explained.
Excellent CDC guideline statement regarding the role of screening expectant mothers and administering prophylactic antibiotic therapy to reduce rates of invasive GBS disease among newborns. The universal screening strategy initially recommended in 1996 and revised twice since then has been associated with substantial rates in reduction of early-onset invasive GBS disease.
Comment: A relatively easy to understand review of green strep, though this remains fluid with to be sure future changes.
Comment: Interesting review article highlighting the emergence of S. suis as a zoonotic pathogen among pig farmers, particularly in southeast Asia, where it is a not uncommon cause of meningitis and hearing loss.
Comment: Comprehensive review of invasive S. agalactiae infections in non-pregnant adults. Authors note that diabetes and immunocompromise increase risk of infection. Bacteremia and skin/soft tissue infections are the most common kinds of infections, although toxic shock syndrome and necrotizing fasciitis are more recently recognized conditions related to this bacterium.
Comment: Although controversial, dexamethasone is now used as part of the treatment of adults with confirmed or suspected bacterial meningitis in southern Vietnam, in large part because of the positive impact on morbidity and mortality seen in cases of S. suis meningitis in this study.
Comment: Levels of resistance seen with overall frequencies of erythromycin and clindamycin resistance were 11% and 4.7%, respectively. Inducible resistance was documented in some.
Comment: Largest outbreak of severe Group A strep pneumonia in > 30 years occurred in a military setting. This speaks to the potential for this organism to cause epidemic disease in close settings.
Comment: Raising rates of GBS infection in the elderly may be explained by the finding that colonization rates are similar, but elderly are more likely to be colonized by the V type that causes invasive disease.
Comment: Among 15 Abiotrophia and Granulicatella isolates, ten demonstrated intermediate resistance to penicillin, and 3 were resistant.
Comment: Retrospective study highlights long known association with colon cancer (17/45 pts 41%), but also notes that 5/45 were found to have an extra-gastrointestinal malignancy.
Comment: The authors report data on 122 cases of Streptococcus milleri (now called either Streptococcus intermedius or S. anginosus Group) infection over a 1 year period. They found that 41/56 isolates of S. constellatus, 10/14 S. intermedius and 10/52 S. S. constellatus infections were associated with abscess formation. In addition, they note that S. intermedius was usually found as a monomicrobial pathogen, while S. constellatus and S. anginosus tended to cause polymicrobial infections.
Comment: Penicillin resistance among viridans group streptococci shown to have reached 48.5% in U.S among isolates tested.
Comment: Group A, B and G account for most cases, with only Group A associated with toxic-shock like features.
Comment: This report is similar to five earlier studies showing that GBS in adult patients, most (66%) were more than 50 years old. Primary bacteremia was the most frequent clinical diagnosis, occurring in 7 (22%) of 32 patients. Nonhematologic cancer was the most frequently associated condition (25%). Nineteen percent of the patients had diabetes mellitis. The overall mortality rate was 31% and was significantly associated with increasing age.
Comment: A study utilizing percutaneous microbiologic specimens of pulmonary infiltrates and pleural collections. A high proportion were found to involve organisms of the Streptococcus milleri group and synergy provided by oral anaerobic bacteria was demonstrated too.
Comment: Report highlights the growing emergence of severe bacteremia (often continuous) in patients undergoing chemotherapy. Between 1972 and 1989, the incidence of viridans streptococcal bacteremia at the University of Texas M. D. Anderson Cancer Center in Houston increased from one case per 10,000 admissions to 47 cases per 10,000 admissions (P less than .0001). Risk factors also included TMP-SMX or FQ use, use of antacids leading others to suspect gastric source from chemotherapy-induced irritation. A shock syndrome w/hypotension, rash, palmar desquamation, ARDS developed in 26% of patients.
Comment: Frequently cited paper indicating a high rate of rejection of blood cultures growing viridans streptococci as being contaminants (approximately 4 of 5 were felt to be such). This paper again highlights the "art" of medicine in the need to carefully weigh each situation rather than to have "knee jerk" responses to clinical microbiological data.
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