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Microbiology Spectrum Mar 2019Invasive disease due to group B infection () results in a wide spectrum of clinical disease. In North America, serotypes Ia, Ib, II, III, and V are most frequently... (Review)
Review
Invasive disease due to group B infection () results in a wide spectrum of clinical disease. In North America, serotypes Ia, Ib, II, III, and V are most frequently associated with invasive disease. Group B remains a continuing source of morbidity and mortality in high-risk populations, including pregnant women, neonates, and the elderly; an increasing incidence of invasive disease has been observed in nonpregnant adults. Group B remains the most common culture-confirmed neonatal bacterial infection in the United States and is a significant source of neonatal morbidity globally. Intrapartum antibiotic prophylaxis has reduced the incidence of early-onset neonatal disease without a notable impact on the incidence of late-onset neonatal disease. Penicillin G remains the mainstay of therapy, although reduced penicillin susceptibility has been observed in select isolates. Increased frequency of resistance to non-beta-lactam antibiotics, including clindamycin, erythromycin, and fluoroquinolones, has been observed, with some isolates demonstrating resistance to vancomycin. The development and implementation of strategies to identify hosts, treat judiciously with antimicrobials with the narrowest spectra, and prevent invasive disease, with vaccines, are essential to reduce the burden of group B disease.
Topics: Adult; Aged; Anti-Bacterial Agents; Antibiotic Prophylaxis; Female; Humans; Infant, Newborn; Infant, Newborn, Diseases; Pregnancy; Pregnancy Complications, Infectious; Streptococcal Infections; Streptococcus agalactiae
PubMed: 30900541
DOI: 10.1128/microbiolspec.GPP3-0007-2018 -
Clinical Microbiology Reviews Oct 2018, or group B streptococcus (GBS), is a major neonatal pathogen. Recent data have elucidated the global prevalence of maternal and neonatal colonization, but gaps still... (Review)
Review
, or group B streptococcus (GBS), is a major neonatal pathogen. Recent data have elucidated the global prevalence of maternal and neonatal colonization, but gaps still remain in the epidemiology of this species. A number of phenotypic and genotypic classifications can be used to identify the diversity of GBS strains, and some are more discriminatory than others. This review explores the main schemes used for GBS epidemiology and further details the targets for epidemiological surveillance. Current screening practices across the world provide a unique opportunity to gain detailed information on maternal colonizing strains and neonatal disease-causing strains, which is vital for monitoring and therapeutics, if sufficient detail can be extracted. Deciphering which isolates are circulating within specific populations and recording targets within invasive strains are crucial steps in monitoring the implementation of therapeutics, such as vaccines, as well as developing novel therapies against prevalent GBS strains. Having a detailed understanding of global GBS epidemiology will prove invaluable for understanding the pathogenesis of this organism and equipping future prevention strategies for success.
Topics: Epidemiological Monitoring; Female; Humans; Pregnancy; Prevalence; Streptococcal Infections; Streptococcus agalactiae
PubMed: 30111577
DOI: 10.1128/CMR.00049-18 -
Journal of Molecular Biology Jul 2019Group B streptococcus (GBS) is a β-hemolytic gram-positive bacterium that colonizes the lower genital tract of approximately 18% of women globally as an asymptomatic... (Review)
Review
Group B streptococcus (GBS) is a β-hemolytic gram-positive bacterium that colonizes the lower genital tract of approximately 18% of women globally as an asymptomatic member of the gastrointestinal and/or vaginal flora. If established in other host niches, however, GBS is highly pathogenic. During pregnancy, ascending GBS infection from the vagina to the intrauterine space is associated with preterm birth, stillbirth, and fetal injury. In addition, vertical transmission of GBS during or after birth results in life-threatening neonatal infections, including pneumonia, sepsis, and meningitis. Although the mechanisms by which GBS traffics from the lower genital tract to vulnerable host niches are not well understood, recent advances have revealed that many of the same bacterial factors that promote asymptomatic vaginal carriage also facilitate dissemination and virulence. Furthermore, highly pathogenic GBS strains have acquired unique factors that enhance survival in invasive niches. Several host factors also exist that either subdue GBS upon vaginal colonization or alternatively permit invasive infection. This review summarizes the GBS and host factors involved in GBS's state as both an asymptomatic colonizer and an invasive pathogen. Gaining a better understanding of these mechanisms is key to overcoming the challenges associated with vaccine development and identification of novel strategies to mitigate GBS virulence.
Topics: Female; Humans; Pregnancy; Pregnancy Complications, Infectious; Streptococcal Infections; Streptococcus agalactiae; Symbiosis; Uterus; Vagina; Virulence
PubMed: 30711542
DOI: 10.1016/j.jmb.2019.01.035 -
Proceedings of the National Academy of... Sep 2005The development of efficient and inexpensive genome sequencing methods has revolutionized the study of human bacterial pathogens and improved vaccine design....
The development of efficient and inexpensive genome sequencing methods has revolutionized the study of human bacterial pathogens and improved vaccine design. Unfortunately, the sequence of a single genome does not reflect how genetic variability drives pathogenesis within a bacterial species and also limits genome-wide screens for vaccine candidates or for antimicrobial targets. We have generated the genomic sequence of six strains representing the five major disease-causing serotypes of Streptococcus agalactiae, the main cause of neonatal infection in humans. Analysis of these genomes and those available in databases showed that the S. agalactiae species can be described by a pan-genome consisting of a core genome shared by all isolates, accounting for approximately 80% of any single genome, plus a dispensable genome consisting of partially shared and strain-specific genes. Mathematical extrapolation of the data suggests that the gene reservoir available for inclusion in the S. agalactiae pan-genome is vast and that unique genes will continue to be identified even after sequencing hundreds of genomes.
Topics: Amino Acid Sequence; Bacterial Capsules; Base Sequence; Gene Expression; Genes, Bacterial; Genetic Variation; Genome, Bacterial; Molecular Sequence Data; Phylogeny; Sequence Alignment; Sequence Analysis, DNA; Streptococcus agalactiae; Virulence
PubMed: 16172379
DOI: 10.1073/pnas.0506758102 -
Viruses Nov 2020(group B Streptococcus, GBS) represents a leading cause of invasive bacterial infections in newborns and is also responsible for diseases in older and immunocompromised...
(group B Streptococcus, GBS) represents a leading cause of invasive bacterial infections in newborns and is also responsible for diseases in older and immunocompromised adults. Prophages represent an important factor contributing to the genome plasticity and evolution of new strains. In the present study, prophage content was analyzed in human GBS isolates. Thirty-seven prophages were identified in genomes of 20 representative sequenced strains. On the basis of the sequence comparison, we divided the prophages into eight groups named A-H. This division also corresponded to the clustering of phage integrase, even though several different integration sites were observed in some relative prophages. Next, PCR method was used for detection of the prophages in 123 GBS strains from adult hospitalized patients and from pregnancy screening. At least one prophage was present in 105 isolates (85%). The highest prevalence was observed for prophage group A (71%) and satellite prophage group B (62%). Other groups were detected infrequently (1-6%). Prophage distribution did not differ between clinical and screening strains, but it was unevenly distributed in MLST (multi locus sequence typing) sequence types. High content of full-length and satellite prophages detected in present study implies that prophages could be beneficial for the host bacterium and could contribute to evolution of more adapted strains.
Topics: Adaptation, Physiological; Adolescent; Adult; Aged; Aged, 80 and over; Bacterial Typing Techniques; Carrier State; Female; Genetic Variation; Genome, Bacterial; Humans; Middle Aged; Multilocus Sequence Typing; Phylogeny; Pregnancy; Prophages; Streptococcal Infections; Streptococcus agalactiae; Virus Integration; Whole Genome Sequencing; Young Adult
PubMed: 33217933
DOI: 10.3390/v12111323 -
Frontiers in Cellular and Infection... 2015Streptococcus agalactiae (Group B Streptococcus, GBS) is an important human pathogen that colonizes the urogenital and/or the lower gastro-intestinal tract of up to 40%... (Review)
Review
Streptococcus agalactiae (Group B Streptococcus, GBS) is an important human pathogen that colonizes the urogenital and/or the lower gastro-intestinal tract of up to 40% of healthy women of reproductive age and is a leading cause of sepsis and meningitis in the neonates. GBS can also infect the elderly and immuno-compromised adults, and is responsible for mastitis in bovines. Like other Gram-positive bacteria, GBS can form biofilm-like three-dimensional structures that could enhance its ability to colonize and persist in the host. Biofilm formation by GBS has been investigated in vitro and appears tightly controlled by environmental conditions. Several adhesins have been shown to play a role in the formation of GBS biofilm-like structures, among which are the protein components of pili protruding outside the bacterial surface. Remarkably, antibodies directed against pilus proteins can prevent the formation of biofilms. The implications of biofilm formation in the context of GBS asymptomatic colonization and dissemination to cause invasive disease remain to be investigated in detail.
Topics: Bacterial Proteins; Biofilms; Humans; Streptococcal Infections; Streptococcus agalactiae; Virulence Factors
PubMed: 25699242
DOI: 10.3389/fcimb.2015.00006 -
Brazilian Journal of Microbiology :... Oct 2019Brazilian data for maternal GBS colonization shows different prevalence rates. This conflicting data may be related to the absence of an official recommendation from the... (Review)
Review
Brazilian data for maternal GBS colonization shows different prevalence rates. This conflicting data may be related to the absence of an official recommendation from the Federal Brazilian Health Authorities describing guidelines and protocols to perform GBS screening in pregnant women, in both public and private clinics. In the present review, we evaluated published reports addressing the prevalence of GBS in different regions of the country, methods used, and, when available, information regarding antibiotic resistance and serological typing of clinical isolates. According to this review, GBS prevalence in pregnant women in Brazil ranged from 4.2 to 28.4%, in the last 10 years. Serotype Ia was the most prevalent. The highest antibiotic resistance rates were found for tetarcycline, although its use to treat GBS infections is not common. Our results also show high resistance rates to clindamycin and erythromycin, which are commonly used as an alternative to penicillin in GBS infecctions. The increased antibiotic resistance, variations in serotype distribution, and high GBS prevalences need to be further investigated. Based on the present situation, recommendations regarding GBS surveillance in the country were raised and may improve our strategies for preventing neonatal infections.
Topics: Anti-Bacterial Agents; Brazil; Drug Resistance, Bacterial; Female; Humans; Pregnancy; Pregnancy Complications, Infectious; Serogroup; Streptococcal Infections; Streptococcus agalactiae
PubMed: 31432465
DOI: 10.1007/s42770-019-00129-8 -
MicrobiologyOpen May 2019Streptococcus agalactiae is a highly pathogenic bacterium of aquatic species and terrestrial animals worldwide, whereas chitin and its derivative chitosan are among the...
Streptococcus agalactiae is a highly pathogenic bacterium of aquatic species and terrestrial animals worldwide, whereas chitin and its derivative chitosan are among the most abundant biopolymers found in nature, including the aquatic milieu. The present investigation focused on the capability of S. agalactiae to degrade and utilize these polymers. Growth of S. agalactiae in the presence of colloid chitin, chitosan, or N-acetyl-glucosamine (GlcNAc) was evaluated. Chitosanase production was measured daily over 7 days of growth period and degraded products were evaluated with thin later chorography. Chitin had no effect on the growth of S. agalactiae. Degraded chitin, however, stimulated the growth of S. agalactiae. S. agalactiae cells did not produce chitinase to degrade chitin; however, they readily utilize GlcNAc (product of degraded chitin) as sole source of carbon and nitrogen for growth. Chitosan at high concentrations had antibacterial activities against S. agalactiae, while in the presence of lower than the inhibitory level of chitosan in the medium, S. agalactiae secrets chitosanase to degrade chitosan, and utilizes it to a limited extent to benefit growth. The interaction of S. agalactiae with chitin hydrolytes and chitosan could play a role in the diverse habitat distribution and pathogenicity of S. agalactiae worldwide.
Topics: Acetylglucosamine; Chitin; Chitosan; Chromatography, Thin Layer; Hydrolysis; Streptococcus agalactiae
PubMed: 30272387
DOI: 10.1002/mbo3.733 -
MicrobiologyOpen Nov 2021Although Streptococcus agalactiae periprosthetic joint infection (PJI) is not as prevalent as staphylococcal PJI, invasive S. agalactiae infection is not uncommon. Here,...
Although Streptococcus agalactiae periprosthetic joint infection (PJI) is not as prevalent as staphylococcal PJI, invasive S. agalactiae infection is not uncommon. Here, RNA-seq was used to perform transcriptomic analysis of S. agalactiae PJI using fluid derived from sonication of explanted arthroplasties of subjects with S. agalactiae PJI, with results compared to those of S. agalactiae strain NEM316 grown in vitro. A total of 227 genes with outlier expression were found (164 upregulated and 63 downregulated) between PJI sonicate fluid and in vitro conditions. Functional enrichment analysis showed genes involved in mobilome and inorganic ion transport and metabolism to be most enriched. Genes involved in nickel, copper, and zinc transport, were upregulated. Among known virulence factors, cyl operon genes, encoding β-hemolysin/cytolysin, were consistently highly expressed in PJI versus in vitro. The data presented provide insight into S. agalactiae PJI pathogenesis and may be a resource for identification of novel PJI therapeutics or vaccines against invasive S. agalactiae infections.
Topics: Adult; Aged; Bacterial Adhesion; Biofilms; Female; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Genes, Bacterial; Genome, Bacterial; Humans; Joint Prosthesis; Male; Middle Aged; Prosthesis-Related Infections; RNA-Seq; Streptococcal Infections; Streptococcus agalactiae; Transcriptome; Virulence Factors; Whole Genome Sequencing
PubMed: 34964296
DOI: 10.1002/mbo3.1256 -
MBio Jun 2020(group B streptococcus; GBS) is a colonizer of the gastrointestinal and urogenital tracts, and an opportunistic pathogen of infants and adults. The worldwide population...
(group B streptococcus; GBS) is a colonizer of the gastrointestinal and urogenital tracts, and an opportunistic pathogen of infants and adults. The worldwide population of GBS is characterized by clonal complexes (CCs) with different invasive potentials. CC17, for example, is a hypervirulent lineage commonly associated with neonatal sepsis and meningitis, while CC1 is less invasive in neonates and more commonly causes invasive disease in adults with comorbidities. The genetic basis of GBS virulence and the extent to which different CCs have adapted to different host environments remain uncertain. We have therefore applied a pan-genome-wide association study (GWAS) approach to 1,988 GBS strains isolated from different hosts and countries. Our analysis identified 279 CC-specific genes associated with virulence, disease, metabolism, and regulation of cellular mechanisms that may explain the differential virulence potential of particular CCs. In CC17 and CC23, for example, we have identified genes encoding pilus, quorum-sensing proteins, and proteins for the uptake of ions and micronutrients which are absent in less invasive lineages. Moreover, in CC17, carriage and disease strains were distinguished by the allelic variants of 21 of these CC-specific genes. Together our data highlight the lineage-specific basis of GBS niche adaptation and virulence. GBS is a leading cause of mortality in newborn babies in high- and low-income countries worldwide. Different strains of GBS are characterized by different degrees of virulence, where some are harmlessly carried by humans or animals and others are much more likely to cause disease.The genome sequences of almost 2,000 GBS samples isolated from both animals and humans in high- and low- income countries were analyzed using a pan-genome-wide association study approach. This allowed us to identify 279 genes which are associated with different lineages of GBS, characterized by a different virulence and preferred host. Additionally, we propose that the GBS now carried in humans may have first evolved in animals before expanding clonally once adapted to the human host.These findings are essential to help understand what is causing GBS disease and how the bacteria have evolved and are transmitted.
Topics: Adaptation, Physiological; Animals; Anti-Bacterial Agents; Genome, Bacterial; Genome-Wide Association Study; Host Microbial Interactions; Humans; Internationality; Phylogeny; Streptococcal Infections; Streptococcus agalactiae; Virulence; Virulence Factors
PubMed: 32518186
DOI: 10.1128/mBio.00728-20