CAMP test v1

2021 ◽  
Author(s):  
lydiariver not provided
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Agalactiae ◽  
Group B Streptococcus ◽  
Blood Agar ◽  
Camp Factor ◽  
Camp Test ◽  
Group B

Group B Streptococcus agalactiae has CAMP factor which allow it to hemolized zones when it is grown on blood agar plates near to Staphylococcus aureus ATCC 25293 colonies, this effect is brought about by Staphylococcus aureus sphingomyelinase.

scholarly journals Synergistic hemolysis phenomenon shown by an alpha-toxin-producing Clostridium perfingens and streptococcal CAMP factor in presumptive streptococcal grouping

1978 ◽  
Vol 8 (5) ◽  
pp. 480-488
Author(s):  
S M Gubash
Keyword(s):  
Human Blood ◽  
Test Group ◽  
Blood Agar ◽  
Group A Streptococci ◽  
Alpha Toxin ◽  
Group B Streptococci ◽  
Camp Factor ◽  
Group A ◽  
Camp Test ◽  
Group B

A new phenomenon of synergistic hemolysis by Clostridium perfringens alpha-toxin and the streptococcal CAMP factor on human and guinea pig erythrocytes is described. A possible mode of action of the CAMP factors is suggested. On human blood agar all of the tested isolates of group B streptococci gave an arrowhead-shaped zone of hemolysis; 74% of group A gave a crescent-shaped lytic zone, whereas all isolates of groups C and G and the remaining 26% of group A streptococci gave a bullet-shaped lytic zone. By comparison, in the CAMP test incubated aerobically and anaerobically, 70 and 91%, respectively, of streptococci other than group B gave positive, arrowhead-shaped lytic zones. If all intermediate positive reactions in the CAMP tests were read as negative after aerobic incubation, only 89% of group B streptococci would be properly identified. The synergistic hemolysis phenomenon, using an alpha-toxin-producing C. perfringens and human blood agar, provided a reliable test for presumptive identification of group B streptococci, with promising potential to differentiate in the same test group A streptococci from other groups.

scholarly journals Genetic Basis Underlying the Hyperhemolytic Phenotype of Streptococcus agalactiae Strain CNCTC10/84

2020 ◽  
Vol 202 (23) ◽  
Author(s):  
Luchang Zhu ◽  
Stephen B. Beres ◽  
Prasanti Yerramilli ◽  
Layne Pruitt ◽  
Concepcion C. Cantu ◽  
...  
Keyword(s):  
Streptococcus Agalactiae ◽  
Hemolytic Activity ◽  
Genetic Basis ◽  
Group B Streptococcus ◽  
Single Nucleotide ◽  
Altered Expression ◽  
Homopolymeric Tract ◽  
Camp Factor ◽  
Nucleotide Insertion ◽  
Group B

ABSTRACT Streptococcus agalactiae (group B streptococcus [GBS]) is a major cause of infections in newborns, pregnant women, and immunocompromised patients. GBS strain CNCTC10/84 is a clinical isolate that has high virulence in animal models of infection and has been used extensively to study GBS pathogenesis. Two unusual features of this strain are hyperhemolytic activity and hypo-CAMP factor activity. These two phenotypes are typical of GBS strains that are functionally deficient in the CovR-CovS two-component regulatory system. A previous whole-genome sequencing study found that strain CNCTC10/84 has intact covR and covS regulatory genes. We investigated CovR-CovS regulation in CNCTC10/84 and discovered that a single-nucleotide insertion in a homopolymeric tract in the covR promoter region underlies the strong hemolytic activity and weak CAMP activity of this strain. Using isogenic mutant strains, we demonstrate that this single-nucleotide insertion confers significantly decreased expression of covR and covS and altered expression of CovR-CovS-regulated genes, including that of genes encoding β-hemolysin and CAMP factor. This single-nucleotide insertion also confers significantly increased GBS survival in human whole blood ex vivo. IMPORTANCE Group B streptococcus (GBS) is the leading cause of neonatal sepsis, pneumonia, and meningitis. GBS strain CNCTC10/84 is a highly virulent blood isolate that has been used extensively to study GBS pathogenesis for over 20 years. Strain CNCTC10/84 has an unusually strong hemolytic activity, but the genetic basis is unknown. In this study, we discovered that a single-nucleotide insertion in an intergenic homopolymeric tract is responsible for the elevated hemolytic activity of CNCTC10/84.

scholarly journals Structure determination of the CAMP factor of Streptococcus agalactiae with the aid of an MBP tag and insights into membrane-surface attachment

2019 ◽  
Vol 75 (8) ◽  
pp. 772-781 ◽  
Author(s):  
Yajuan Li ◽  
Weihong Zeng ◽  
Yuelong Li ◽  
Weirong Fan ◽  
Huan Ma ◽  
...  
Keyword(s):  
Structure Determination ◽  
Streptococcus Agalactiae ◽  
Membrane Surface ◽  
Heavy Atom ◽  
Group B Streptococcus ◽  
Bacterial Toxin ◽  
Camp Factor ◽  
Interaction Interface ◽  
Group B

CAMP factor is a unique α-helical bacterial toxin that is known for its co-hemolytic activity in combination with staphylococcal sphingomyelinase. It was first discovered in the human pathogen Streptococcus agalactiae (also known as group B streptococcus), but homologous genes have been found in many other Gram-positive pathogens. In this study, the efforts that led to the determination of the first structure of a CAMP-family toxin are reported. Initially, it was possible to produce crystals of the native protein which diffracted to near 2.45 Å resolution. However, a series of technical obstacles were encountered on the way to structure determination. Over a period of more than five years, many methods, including selenomethionine labeling, mutations, crystallization chaperones and heavy-atom soaking, were attempted, but these attempts resulted in limited progress. The structure was finally solved using a combination of iodine soaking and molecular replacement using the crystallization chaperone maltose-binding protein (MBP) as a search model. Analysis of native and MBP-tagged CAMP-factor structures identified a conserved interaction interface in the C-terminal domain (CTD). The positively charged surface may be critical for binding to acidic ligands. Furthermore, mutations on the interaction interface at the CTD completely abolished its co-hemolytic activities. This study provides novel insights into the mechanism of the membrane-permeabilizing activity of CAMP factor.

scholarly journals The Recombinant Expression Proteins FnBP and ClfA From Staphylococcus aureus in Addition to GapC and Sip From Streptococcus agalactiae Can Protect BALB/c Mice From Bacterial Infection

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhongchen Ma ◽  
Xinyue Yin ◽  
Peng Wu ◽  
Ruirui Hu ◽  
Yong Wang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Agalactiae ◽  
Vaccine Development ◽  
Recombinant Expression ◽  
Group B Streptococcus ◽  
Chimeric Protein ◽  
Chimeric Proteins ◽  
Serious Disease ◽  
Group B ◽  
Lethal Doses

Dairy cow mastitis is a serious disease that is mainly caused by intramammary infection with Staphylococcus aureus and Streptococcus agalactiae [group B streptococcus (GBS)]. FnBP and ClfA are the virulence factors of S. aureus, while GapC is the respective factor for S. agalactiae. Sip is a highly immunogenic protein, and it is conserved in all GBS serotypes. In this study, we analyzed the abovementioned four genes prepared a FnBP+ClfA chimeric protein (FC), a GapC+Sip chimeric protein (GS), and a FnBP+ClfA+GapC+Sip chimeric protein (FCGS) based on the antigenic sites to evaluate their use in vaccine development. After expression and purification of the recombinant proteins in Escherichia coli, BALB/c mice were immunized with them to examine resistance effects. The total lethal and half lethal doses of S. aureus and S. agalactiae were then measured, and the immunoprotective effects of the fusion proteins were evaluated. The FC and FCGS chimeric proteins could induce mice to produce high levels of antibodies, and bacterial loads were significantly reduced in the spleens and livers after challenge. After immunization with FCGS, the recipients resisted the attacks of both S. aureus and S. agalactiae, indicating the potential of the fusion protein as a mastitis vaccine.

An Emerging Infection: Streptococcal Toxic Shock-Like Syndrome Caused By Group B Streptococcus (GBS), Streptococcus Agalactiae

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S140-S140
Author(s):  
F Rajack ◽  
A Afsari ◽  
A M Ramadan ◽  
T J Naab
Keyword(s):  
Soft Tissue ◽  
Necrotizing Fasciitis ◽  
Streptococcus Agalactiae ◽  
Group A Streptococcus ◽  
Multiorgan Failure ◽  
Group B Streptococcus ◽  
Stage Iii ◽  
Streptococcal Toxic Shock Syndrome ◽  
Toxic Shock ◽  
Group B

Abstract Introduction/Objective Streptococcus agalactiae, Group B Streptococcus (GBS), is a major cause of neonatal sepsis and infections in pregnant women. However, incidence of invasive GBS infections has more than doubled in the last two decades with highest risk in adults 65 years or older. Other risk factors are diabetes, malignancy, and immunocompromised state. Bacteremia and skin soft tissue infections are the most common invasive infections in nonpregnant adults. Rarely GBS infection has a fulminating pyrogenic exotoxin-mediated course characterized by acute onset, multiorgan failure, shock, and sometimes death, referred to as toxic shock-like syndrome. Methods A 77-year-old hypertensive female with uncontrolled type 2 diabetes mellitus and a history of bilateral foot ulcers presented to the hospital in probable septic shock. Clinical diagnosis of necrotizing fasciitis was made and she underwent bilateral lower limb amputations. Results Grossly soft tissue appeared gray. Microscopically fascia was necrotic without neutrophils present and Gram stain revealed sheets of Gram positive cocci. These findings reflected histopathologic Stage III necrotizing fasciitis, which is associated with 47% mortality. Autopsy showed a similar histology of Stage III necrotizing fasciitis involving the surgical stump. Erythema and desquamation of the upper limbs bilaterally and multi-organ failure met the clinical picture of Streptococcal Toxic Shock Syndrome (STSS) and fulfilled the criteria for TSS due to Group A Streptococcus (GAS), defined by The Working Group on Severe Streptococcal Infections. Conclusion Group B Streptococcal Toxic Shock-Like Syndrome may have a similar outcome to STSS caused by GAS and other pathogens and, in limited studies, mortality has been 30% or greater.

scholarly journals Prevalence and Serotype Determination of Streptococcus agalactiae Isolated From Non-Pregnant Women in Tehran, Iran

2020 ◽  
Author(s):  
Leila Goudarzi ◽  
Mohammad Bagher Khalili ◽  
Mahmood Vakili ◽  
Maryam Sadeh
Keyword(s):  
Pregnant Women ◽  
Streptococcus Agalactiae ◽  
Group B Streptococcus ◽  
Cross Sectional Study ◽  
Chi Square ◽  
Cross Sectional ◽  
Specific Pcr ◽  
Pcr Method ◽  
Group B ◽  
Tehran Area

Consequence of Streptococcus agalactiae, Group B Streptococcus (GBS) relating infant’s diseases are well documented. Although many women carry this bacterium in their vagina, they may transfer to their infant during delivery and may result in different neonatal invasive diseases. The aim of this study was to determine the prevalence of GBS and serotyping the isolated species among un-selective non-pregnant women who attended two gynecology clinics in Tehran. In this cross-sectional study, a total of 560 vaginal samples collected from non-pregnant women. Following inoculation of the specimen on Blood Agar, the standard technology was applied for the final identification of GBS. Detected GBS species were further confirmed using specific PCR directed on dlts gene. Capsular serotyping was done by using the multiplex PCR method. The chi-square method was used for statistical analysis. Fifty (8.9%) out of 560 non-pregnant women were carriers of GBS. The most common types were III (36%), followed by type II (32%), Ia (26%), and Ib (6%), respectively. Results represent that the prevalence rate of GBS in non-pregnant women was reliable and similar to what obtained from pregnant women. In addition, the serotype III was found the most dominant types, as well as other investigations in the Tehran area. Therefore, vaccine designation based on type III is recommended.

scholarly journals Diagnostic Performance of Various Methodologies for Group B Streptococcus Screening in Pregnant Woman in China

2021 ◽  
Vol 11 ◽  
Author(s):  
Kankan Gao ◽  
Qiulian Deng ◽  
Lianfen Huang ◽  
Chien-Yi Chang ◽  
Huamin Zhong ◽  
...  
Keyword(s):  
Group B Streptococcus ◽  
Agar Plate ◽  
Reference Method ◽  
Antigen Detection ◽  
The Other ◽  
Blood Agar ◽  
Blood Agar Plate ◽  
Chromogenic Agar ◽  
Group B ◽  
Detection Reagent

Maternal vaginal/rectal colonization of group B streptococcus (GBS) is a main risk for neonatal invasive infection. Efficient determination of GBS colonization in pregnant women is crucial. This study aimed to investigate the prevalence of GBS carriage and evaluate the diagnostic performance of six methodologies for GBS screening conducted in China, including blood agar plate, liquid chromogenic medium, and loop-mediated isothermal amplification (LAMP) without pre-enrichment, chromogenic agar plate with pre-enrichment, and GBS antigen detection without and with pre-enrichment in comparison with the standard reference method (Lim broth-enriched subculture with plating on 5% sheep blood agar). Vaginal/rectal swabs were collected from 1,281 pregnant women at 35–37 weeks of gestation. Of them, 309 were taken in triplicate, one for Lim broth-enriched subculture, one for blood agar plate, and the third for GBS antigen detection (Reagent W); 177 were acquired in duplicate, one for Lim broth-enriched subculture and the other for GBS antigen detection (Reagent H); 502 were obtained in duplicate, one for Lim broth-enriched subculture and the other for liquid chromogenic medium; 158 were collected in duplicate, one for Lim broth-enriched subculture and the other for LAMP; and 135 were inoculated in Lim broth-enriched for GBS antigen detection (Reagent W) and subculture with chromogenic agar plate and 5% blood agar plate. The overall prevalence of GBS carriage was 10.1% (130/1,281, 95% CI: 8.5–12.1%) according to the standard reference method. Compared with the standard reference method, the LAMP had excellent performance of sensitivity (100%, 95%CI: 83.4–100%), specificity (94%, 95%CI: 88.1–97.1%), and Yoden index (0.940); as well as the blood agar plate with sensitivity (81.5%, 95%CI: 61.3–93.0%), specificity (100%, 95%CI: 98.3–100.0%), and Yoden index (0.815). The other four methods were not sufficient to reach the threshold in terms of sensitivity or specificity compared to the standard reference method. Furthermore, for LAMP, results can be obtained within 0.5–1 h, while for blood agar plate, which needed 24–48 h, and further identification was required. Our data suggested that the performance of LAMP was highly comparable to the standard Lim broth-enriched subculture and LAMP is considered as an alternative for fast and accurate GBS screening.

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