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Group B Streptococcal Infections [keywords]
- Expression, purification and crystallization of the C-terminal LRR domain of Streptococcus pyogenes protein 0843. [Journal Article]
- Acta Crystallogr Sect F Struct Biol Cryst Commun 2013 May; 69(Pt 5):559-61.
Streptococcus pyogenes protein 0843 (Spy0843) is a recently identified protein with a potential adhesin function. Sequence analysis has shown that Spy0843 contains two leucine-rich repeat (LRR) domains that mediate interactions with the gp340 receptor. Here, the C-terminal LRR domain was overexpressed in Escherichia coli, purified and crystallized in the presence of 1.7-1.8 M ammonium sulfate pH 7.4 as precipitant. Data were collected from a single crystal to 1.59 Å resolution at 100 K at a synchrotron-radiation source. The crystal was found to belong to space group I41, with unit-cell parameters a = b = 121.4, c = 51.5 Å and one molecule in the asymmetric unit. Elucidation of the crystal structure will provide insights into the interactions of Spy0843 with the gp340 receptor and a better understanding of the role of Spy0843 in streptococcal infections.
- Invasive group B streptococcal disease in two pediatric patients with systemic lupus erythematosus. [Journal Article]
- Case Rep Pediatr 2013.:896014.
Systemic lupus erythematosus (SLE) is an autoimmune disease associated with high morbidity and mortality, often caused by infection. We report two patients with SLE who were treated with steroids and immunosuppressive medication and then developed invasive Group B Streptococcus (GBS) infections. While GBS infection is rare in the nonneonatal pediatric age group, GBS should be considered when treating SLE patients presenting with signs of infection.
- High rates of inducible clindamycin resistance among prenatal group B streptococcal isolates in one northwest Louisiana academic medical center. [JOURNAL ARTICLE]
- J Clin Microbiol 2013 Apr 17.
CDC guidelines for prevention of perinatal group B Streptococcus (GBS) infections (1), which recommended universal screening and intrapartum antibiotic prophylaxis (IAP) for pregnant women colonized with GBS or with risk factors that increased intrapartum transmission of GBS, decreased the rate of early-onset (EO) GBS disease to approximately 0.4 per 1000 live births (2).…
- Arcanobacterium haemolyticum Osteomyelitis and Sepsis: A Diagnostic Conundrum. [JOURNAL ARTICLE]
- Surg Infect (Larchmt) 2013 Apr 12.
Background:Arcanobacterium haemolyticum can cause severe systemic infections and sepsis. Thus, accurate and timely identification of the organism is essential.
Methods:Case report and review of the pertinent English-language literature. Case Report: A 74-year-old male underwent repetitive surgical debridement and grafting for a full-thickness ulcer on the plantar surface of the left foot. One week after the last debridement, the patient presented to the emergency department with fever, hypotension, and severe left foot pain. A radiograph showed a soft-tissue defect of the plantar aspect of the left midfoot with gas along the lateral aspect of the fifth metatarsal. A below-knee amputation was performed. Blood culture and intraoperative tissue specimens grew colonies that exhibited β-hemolysis on sheep blood agar and agglutinated with streptococcal B group antiserum. However, gram staining revealed that the organism was a gram-positive bacillus, and a reverse Christie, Atkins, Munch-Peterson (CAMP) test showed that the organism inhibited the β-hemolysis of Staphylococcus aureus on sheep blood agar. Biochemical testing identified the organism as A. haemolyticum.
Conclusions:It is important to investigate for A. haemolyticum when organisms with β-hemolytic activity react with group B streptococcal antiserum. Otherwise, A. haemolyticum can be mis-identified as group B Streptococcus or Listeria monocytogenes. This distinction is important clinically, because despite good in vitro activity of penicillin (a first-line antibiotic for group B Streptococcus infections), treatment failures have been reported when penicillin has been used for A. haemolyticum infections.
- Inducible clindamycin resistance in beta-hemolytic Streptococci and Streptococcus pneumoniae. [Comparative Study, Journal Article]
- Isr Med Assoc J 2013 Jan; 15(1):27-30.
Resistance to macrolides in beta-hemolytic streptococci and Streptococcus pneumoniae arises primarily due to Erm(B) or Mef(A). Erm(B) typically confers high level resistance to macrolides, lincosamides and streptogramin B (MLSB phenotype), whereas Mef(A) confers low level resistance to macrolides only (M phenotype).To investigate the incidence of macrolide resistance mechanisms in isolates of beta-hemolytic streptococci and pneumococci in Israel, with particular emphasis on inducible MLSB phenotype.We collected 316 clinical isolates of streptococci during May-August 2010. Erythromycin resistance mechanism was determined by the erythromycin-clindamycin double disk diffusion method.Erythromycin and clindamycin resistance rates were 19.4% and 13.4% for S. pneumoniae, 4.7% and 1.6% for group A Streptococcus (GAS), 17% and 17% for group B Streptococcus (GBS), and 38.8% and 27.8% for group G Streptococcus (GGS) respectively. The most common resistance mechanism for all streptococci was constitutive MLSB (cMLSB). Inducible MLSs (iMLSB) mechanism was found in 3% of all strains and represented 25% of resistance mechanisms. CONCLUSIONS : The prevalence of macrolide resistance and the distribution of resistance mechanisms differ among beta-hemolytic streptococci and S. pneumoniae, with GBS, GGS and S. pneumoniae showing the highest resistance rate. Macrolide or lincosamide cannot be empirically used for severe streptococcal infections before strains are proved to be susceptible. Continuous surveillance of erythromycin and clindamycin resistance patterns among streptococci is needed.
- Group B streptococcal bacteremia in a major teaching hospital in Malaysia: a case series of eighteen patients. [JOURNAL ARTICLE]
- Int J Infect Dis 2013 Feb 27.
BACKGROUND:Group B Streptococcus (GBS) is a leading cause of infections such as meningitis and septicemia in neonates and pregnant women; however the significance of invasive GBS disease has not been clearly defined in non-pregnant adults.
METHODS:We reviewed the hospital records of 18 cases with GBS bacteremia who attended the Universiti Kebangsaan Malaysia Medical Centre from June 2010 to October 2011. We analyzed the clinical findings of both bacteremic adults and neonates and compared them to previous studies of GBS bacteremia. Serotyping was done by latex agglutination test using 10 distinct antisera (Ia, Ib, and II-IX).
RESULTS:During the period of 1 year and 4 months, there were 18 patients with GBS bacteremia. Five cases occurred in neonates, one in a parturient woman, and 12 in other adults. All neonates with bacteremia were males and two of them were premature. Septicemia was the most common clinical presentation in neonates. They were treated with intravenous (IV) penicillin G and gentamicin. The adults included nine men (69%) and four women (31%). Their mean age was 60 years and all patients had more than two underlying conditions. The most common clinical syndrome was pneumonia (n=6, 46.5%). The others were peritonitis (n=3, 23.1%), primary bacteremia (n=2, 15.5%), septic arthritis (n=2, 15.5%), skin and soft tissue infection (n=1, 7.7%), meningitis (n=1, 8%), urinary tract infection (n=1, 8%), and intravascular device infection (n=1, 7.7%). Cardiovascular diseases (n=7, 53.8%) were the most common underlying conditions, and diabetes mellitus (n=5, 38.5%) was second. The other co-morbid conditions were hyperlipidemia (n=3, 23.1%), renal disease (n=3, 23.1%), liver disease and/or alcohol abuse (n=3, 23.1%), autoimmune disease or immunosuppressive condition (n=2, 15.5%), malignancy (n=2, 15.5%), respiratory disease (n=1, 8%), and postpartum condition (n=1, 8%), as well as miscellaneous conditions including intravenous drug abuse, HIV infection, and trauma (n=2, 15.5%). Polymicrobial bacteremia was found in five (45.4%) cases and Staphylococcus aureus was the most common concurrent bacterial isolate. Of the 18 GBS isolates in both adults and neonates, serotype Ia was predominant (38.9%), followed by VI (27.8%), V (11.1%), and III (5.5%); the remaining 16.7% were non-typeable.
CONCLUSIONS:GBS bacteremia is a significant problem and is associated with serious underlying disease, which may result in a high rate of mortality, not only in neonates and pregnant women, but also in non-pregnant adults.
- Intrapartum antibiotics for known maternal Group B streptococcal colonization. [Journal Article, Meta-Analysis, Research Support, Non-U.S. Gov't, Review]
- Cochrane Database Syst Rev 2013.:CD007467.
Maternal colonization with group B streptococcus (GBS) during pregnancy increases the risk of neonatal infection by vertical transmission. Administration of intrapartum antibiotic prophylaxis (IAP) during labor has been associated with a reduction in early onset GBS disease (EOGBSD). However, treating all colonized women during labor exposes a large number of women and infants to possible adverse effects without benefit.To assess the effect of IAP for maternal GBS colonization on neonatal: 1) all cause mortality and 2) morbidity from proven and probable EOGBSD, late onset GBS disease (LOD), maternal infectious outcomes and allergic reactions to antibiotics.We updated the search of the Cochrane Pregnancy and Childbirth Group's Trials Register on 10 November 2012.Randomized trials assessing the impact of maternal IAP on neonatal GBS infections were included.We independently assessed eligibility and quality of the studies.We did not identify any new trials from the updated search so the results remain unchanged as follows.Three trials (involving 852 women) evaluating the effects of IAP versus no treatment were included. The risk of bias was high. The use of IAP did not significantly reduce the incidence of all cause mortality, mortality from GBS infection or from infections caused by bacteria other than GBS. The incidence of early GBS infection was reduced with IAP compared to no treatment (risk ratio 0.17, 95% confidence interval (CI) 0.04 to 0.74, three trials, 488 infants; risk difference -0.04, 95% CI -0.07 to -0.01; number needed to treat to benefit 25, 95% CI 14 to 100, I(2) 0%). The incidence of LOD or sepsis from organisms other than GBS and puerperal infection was not significantly different between groups.One trial (involving 352 women) compared intrapartum ampicillin versus penicillin and reported no significant difference in neonatal or maternal outcomes.Intrapartum antibiotic prophylaxis appeared to reduce EOGBSD, but this result may well be a result of bias as we found a high risk of bias for one or more key domains in the study methodology and execution. There is lack of evidence from well designed and conducted trials to recommend IAP to reduce neonatal EOGBSD.Ideally the effectiveness of IAP to reduce neonatal GBS infections should be studied in adequately sized double-blind controlled trials. The opportunity to conduct such trials has likely been lost, as practice guidelines (albeit without good evidence) have been introduced in many jurisdictions.
- Intrapartum antibiotic prophylaxis for prevention of group B streptococcal disease in preterm infants. [Comment, Letter]
- Arch Dis Child Fetal Neonatal Ed 2013 Mar; 98(2):F188.
- Late onset group b beta-hemolytic streptococcus infection in a neonate manifesting as a urinary tract infection: a rare clinical presentation. [Case Reports, Journal Article]
- Southeast Asian J Trop Med Public Health 2012 Nov; 43(6):1470-3.
Group B beta-hemolytic streptococcus (GBS) sepsis is a serious bacterial infection in neonates, with significant morbidity and mortality. We report here a neonate with late onset GBS infection manifesting as a urinary tract infection (UTI) in an infant presenting with prolonged neonatal jaundice. The pathogenesis of this late onset is postulated.
- Long-term antibody memory induced by synthetic peptide vaccination is protective against Streptococcus pyogenes infection and is independent of memory T cell help. [Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't]
- J Immunol 2013 Mar 15; 190(6):2692-701.
Streptococcus pyogenes (group A Streptococcus [GAS]) is a leading human pathogen associated with a diverse array of mucosal and systemic infections. Vaccination with J8, a conserved region synthetic peptide derived from the M-protein of GAS and containing only 12 aa from GAS, when conjugated to diphtheria toxoid, has been shown to protect mice against a lethal GAS challenge. Protection has been previously shown to be Ab-mediated. J8 does not contain a dominant GAS-specific T cell epitope. The current study examined long-term Ab memory and dissected the role of B and T cells. Our results demonstrated that vaccination generates specific memory B cells (MBC) and long-lasting Ab responses. The MBC response can be activated following boost with Ag or limiting numbers of whole bacteria. We further show that these memory responses protect against systemic infection with GAS. T cell help is required for activation of MBC but can be provided by naive T cells responding directly to GAS at the time of infection. Thus, individuals whose T cells do not recognize the short synthetic peptide in the vaccine will be able to generate a protective and rapid memory Ab response at the time of infection. These studies significantly strengthen previous findings, which showed that protection by the J8-diphtheria toxoid vaccine is Ab-mediated and suggest that in vaccine design for other organisms the source of T cell help for Ab responses need not be limited to sequences from the organism itself.