Isolation, Antibiogram and Molecular Characterization of Group B Streptococci Isolates from Bovine Mastitis

2021 ◽  
Author(s):  
Rajwent Singh ◽  
A.K. Arora ◽  
T.S. Rai ◽  
Mudit Chandra
Keyword(s):  
Genetic Diversity ◽  
Streptococcus Agalactiae ◽  
Group B Streptococcus ◽  
Bovine Mastitis ◽  
Marker Genes ◽  
Group B Streptococci ◽  
Milk Samples ◽  
Development Of Resistance ◽  
Group B

Background: Group B streptococcus (GBS) or Streptococcus agalactiae is an important pathogen associated with bovine mastitis. The organism is also of public health consequences and may cause variety of infections ranging from neonatal sepsis, pneumonia and meningitis to localized infections and urinary tract infection or arthritisin adult humans. Widespread use of antibiotics in veterinary medicine has led to development of resistance among the pathogens. So there is need for surveillance of antimicrobial resistance to ensure effective treatment. Methods: Milk samples collected from mastitis affected animals were processed for isolation of Streptococcus agalactiae. The isolates were tested for antimicrobial susceptibility. Molecular characterisation was carried out by PCR to study the occurrence of resistance marker genes and virulence marker genes. RAPD was carried out to study genetic diversity among the isolates. Result: Six isolates of S. agalactiae were obtained from 182 milk samples. Highest resistance was observed against co-trimoxazole and tetracycline followed by ampicillin. tetM gene and tetO genes could be amplified in four and three isolates, respectively. None of the isolates showed amplification for ermA, ermB, mefA and mefE genes. Three isolates were positive for the five virulence genes tested (glnA, cfb, hylB, scaA and cyl). RAPD analysis demonstrated great intraspecific genetic diversity among the streptococcal isolates.

scholarly journals Subtractive Hybridization Identifies a Novel Predicted Protein Mediating Epithelial Cell Invasion by Virulent Serotype III Group B Streptococcus agalactiae

2003 ◽  
Vol 71 (12) ◽  
pp. 6857-6863 ◽  
Author(s):  
Elisabeth E. Adderson ◽  
Shinji Takahashi ◽  
Yan Wang ◽  
Jianling Armstrong ◽  
Dylan V. Miller ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Streptococcus Agalactiae ◽  
Group B Streptococcus ◽  
Newborn Infants ◽  
Subtractive Hybridization ◽  
Group B Streptococci ◽  
Mutant Type ◽  
Isogenic Mutant ◽  
Type Iii ◽  
Group B

ABSTRACT Group B Streptococcus agalactiae bacteria (group B streptococci [GBS]) are the most common cause of serious bacterial infection in newborn infants. The majority of serotype III-related cases of neonatal disease are caused by a genetically related subgroup of bacteria, restriction fragment digest pattern (RDP) type III-3, suggesting that these strains possess unique genes contributing to virulence. We used genomic subtractive hybridization to identify regions of genomic DNA unique to virulent RDP type III-3 GBS strains. Within one of these III-3-specific regions is a 1,506-bp open reading frame, spb1 (surface protein of group B streptococcus 1). A mutant type III GBS strain lacking Spb1 was constructed in virulent RDP type III-3 strain 874391, and the interactions of the wild-type and spb1 isogenic mutant with a variety of epithelial cells important to GBS colonization and infection were compared. While adherence of the spb1 isogenic mutant to A549 respiratory, C2Bbe1 colonic, and HeLa cervical epithelial cells was slightly lower than that of the 874391 strain, invasion of the Spb1− mutant was significantly reduced with these cell lines compared to what was seen with 874391. The defect in epithelial invasion was corrected by supplying spb1 in trans. These observations suggest that Spb1 contributes to the pathogenesis of neonatal GBS infection by mediating internalization of virulent serotype III GBS and confirm that understanding of the population structure of bacteria may lead to insights into the pathogenesis of human infections.

scholarly journals Whole-Genome Shotgun Sequence of Streptococcus agalactiae Sequence Type 176 Strain 3966RFQB from a Dairy Herd in Selangor, Malaysia

2019 ◽  
Vol 8 (6) ◽  
Author(s):  
A. Bashir ◽  
Z. Zunita ◽  
F. F. A. Jesse ◽  
S. Z. Ramanoon ◽  
M. L. Mohd-Azmi
Keyword(s):  
Streptococcus Agalactiae ◽  
Group B Streptococcus ◽  
Bovine Mastitis ◽  
Dairy Herd ◽  
Sequence Type ◽  
Control Measures ◽  
Content Type ◽  
Whole Genome Shotgun Sequence ◽  
Genome Shotgun Sequence ◽  
Group B

Streptococcus agalactiae, commonly known as group B streptococcus (GBS), is among the most implicated pathogens in bovine mastitis worldwide. Proper control measures can curb both economic and public health effects it may cause.

scholarly journals Characterization of Clinical and Carrier Streptococcus agalactiae and Prophage Contribution to the Strain Variability

Viruses ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1323
Author(s):  
Aneta Lichvariková ◽  
Katarina Soltys ◽  
Tomas Szemes ◽  
Livia Slobodnikova ◽  
Gabriela Bukovska ◽  
...  
Keyword(s):  
Streptococcus Agalactiae ◽  
Bacterial Infections ◽  
Group B Streptococcus ◽  
Host Bacterium ◽  
Phage Integrase ◽  
Integration Sites ◽  
Group A ◽  
Pcr Method ◽  
Group B

Streptococcus agalactiae (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.

scholarly journals NAD+ pool depletion as a signal for the Rex regulon involved in Streptococcus agalactiae virulence

2021 ◽  
Vol 17 (8) ◽  
pp. e1009791
Author(s):  
Thierry Franza ◽  
Annika Rogstam ◽  
Saravanamuthu Thiyagarajan ◽  
Matthew J. Sullivan ◽  
Aurelie Derré-Bobillot ◽  
...  
Keyword(s):  
Gene Expression ◽  
Streptococcus Agalactiae ◽  
Group B Streptococcus ◽  
Virulence Gene ◽  
Opportunistic Pathogen ◽  
Virulence Gene Expression ◽  
Gram Positive Bacteria ◽  
Virulence Factor Gene ◽  
Group B

In many Gram-positive bacteria, the redox-sensing transcriptional repressor Rex controls central carbon and energy metabolism by sensing the intra cellular balance between the reduced and oxidized forms of nicotinamide adenine dinucleotide; the NADH/NAD+ ratio. Here, we report high-resolution crystal structures and characterization of a Rex ortholog (Gbs1167) in the opportunistic pathogen, Streptococcus agalactiae, also known as group B streptococcus (GBS). We present structures of Rex bound to NAD+ and to a DNA operator which are the first structures of a Rex-family member from a pathogenic bacterium. The structures reveal the molecular basis of DNA binding and the conformation alterations between the free NAD+ complex and DNA-bound form of Rex. Transcriptomic analysis revealed that GBS Rex controls not only central metabolism, but also expression of the monocistronic rex gene as well as virulence gene expression. Rex enhances GBS virulence after disseminated infection in mice. Mechanistically, NAD+ stabilizes Rex as a repressor in the absence of NADH. However, GBS Rex is unique compared to Rex regulators previously characterized because of its sensing mechanism: we show that it primarily responds to NAD+ levels (or growth rate) rather than to the NADH/NAD+ ratio. These results indicate that Rex plays a key role in GBS pathogenicity by modulating virulence factor gene expression and carbon metabolism to harvest nutrients from the host.

scholarly journals In VitroActivity of Solithromycin against Erythromycin-Resistant Streptococcus agalactiae

2013 ◽  
Vol 58 (3) ◽  
pp. 1693-1698 ◽  
Author(s):  
Giorgio Piccinelli ◽  
Prabhavathi Fernandes ◽  
Carlo Bonfanti ◽  
Francesca Caccuri ◽  
Arnaldo Caruso ◽  
...  
Keyword(s):  
Streptococcus Agalactiae ◽  
Group B Streptococcus ◽  
Phenotypic Characterization ◽  
Content Type ◽  
Resistant Strains ◽  
Group B ◽  
Microdilution Broth

ABSTRACTThein vitroantibacterial activity of solithromycin (CEM-101) against macrolide-resistant isolates (n= 62) ofStreptococcus agalactiae(group B streptococcus [GBS]) was determined. Phenotypic characterization of macrolide-resistant strains was performed by double-disc diffusion testing. A multiplex PCR was used to identify theerm(B),erm(TR), andmef(A/E) genes, capsular genotypes, and alpha-like (Alp) protein genes from the GBS strains. Determination of MIC was carried out using the microdilution broth method. The Etest method was used for penicillin, azithromycin, clarithromycin, and erythromycin. Solithromycin had a MIC50of ≤0.008 μg/ml and a MIC90of 0.015 μg/ml against macrolide-susceptibleS. agalactiae. These MICs were lower than those displayed by penicillin (MIC50of 0.032 μg/ml and MIC90of 0.047 μg/ml), the antibiotic agent of choice for prophylaxis and treatment of GBS infections. Against macrolide-resistantS. agalactiae, solithromycin had a MIC50of 0.03 μg/ml and a MIC90of 0.125 μg/ml. Againsterm(B) strains, solithromycin had a MIC50of 0.03 μg/ml and a MIC90of 0.06 μg/ml, while againstmef(A) strains, it had a MIC50of 0.03 μg/ml and a MIC90of 0.125 μg/ml. Most erythromycin-resistant GBS strains were of serotype V (64.5%) and associated significantly withalp2-3. Moreover, a statistically significant association was observed between the constitutive macrolide-lincosamide-streptogramin B resistance (cMLSB) phenotype and theerm(B) gene-carrying strains, thealp2-3gene and the M phenotype, and themef(A/E) gene andepsilon. Overall, our results show that solithromycin had lower or similar MICs than penicillin and potent activity against macrolide-resistant strains independent of their genotype or phenotype, representing a valid therapeutic alternative where β-lactams cannot be used.

scholarly journals Isolation and characterization of group B streptococci from human and bovine sources within and around Nairobi

1997 ◽  
Vol 118 (3) ◽  
pp. 215-220 ◽  
Author(s):  
J. M. MOSABI ◽  
S. M. ARIMI ◽  
E. K. KANG'ETHE
Keyword(s):  
Genetic Relationship ◽  
Human Populations ◽  
Serotype Distribution ◽  
Group B Streptococci ◽  
Milk Samples ◽  
Isolation And Characterization ◽  
Bulk Milk ◽  
Postnatal Women ◽  
Group B

Group B streptococci (GBS) were isolated from bovine bulk milk and from vaginas and throats of antenatal and postnatal women using TKT and rapid GBS media. Sixty-three of 529 (12%) bovine bulk milk samples, 9 of 48 (19%) vaginal and 3 of 48 (6%) throat samples were positive. Both bovine and human beta haemolytic isolates were characterized biochemically and serologically. Pigment production was a characteristic of both human and bovine beta haemolytic isolates. The majority (88%) of human isolates fermented salicin and not lactose and most bovine isolates were either lactose positive/salicin positive (41%) or lactose positive/salicin negative (38%). Human and bovine isolates were 100% and 85% typable respectively. Serotype distribution was similar in the bovine and human populations with serotype la, lc and lll being most common in both. Fermentation of sugars showed major differences between bovine and human isolates but similarity in serotype distribution suggests some genetic relationship.

scholarly journals Distribution of Antimicrobial Resistance and Virulence-Related Genes among Brazilian Group B Streptococci Recovered from Bovine and Human Sources

2005 ◽  
Vol 49 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Rafael S. Duarte ◽  
Bruna C. Bellei ◽  
Otávio P. Miranda ◽  
Maria A. V. P. Brito ◽  
Lúcia M. Teixeira
Keyword(s):  
Genetic Diversity ◽  
Antimicrobial Resistance ◽  
Streptococcus Agalactiae ◽  
Gel Electrophoresis ◽  
Present Report ◽  
Pulsed Field Gel Electrophoresis ◽  
Group B Streptococci ◽  
Pulsed Field ◽  
Group B

ABSTRACT In the present report we describe the characteristics of 189 antimicrobial-resistant Streptococcus agalactiae isolates from bovine (38 isolates) and human (151 isolates) sources. All the strains were resistant to tetracycline (TET), and 16 (8.5%) were also resistant to erythromycin, corresponding to 23.7% of the TET-resistant bovine isolates and 4.6% of the TET-resistant human isolates. The tet(O), erm(B), and mreA resistance-related genes, as well as the bca and scpB virulence-related genes, were the most frequent among the bovine isolates, while the tet(M), erm(A), mreA, bca, lmb, and scpB genes were the most prevalent among the isolates from humans. Although a few major clusters were observed, pulsed-field gel electrophoresis results revealed a variety of profiles, reflecting the substantial genetic diversity among strains of this species isolated from either humans or bovines.

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