Group B Streptococcus and Perinatality in the South of Tunisia: Epidemiology, Serotype Distribution, and Antibiotic Susceptibility.

INTRODUCTION: In the lack of updated Tunisian epidemiological data, we sought to describe the epidemiology of Group B Streptococcus (GBS) in pregnant women and newborns. MATERIALS AND METHODS: A retrospective analysis of GBS neonatal invasive infections and a cross-sectional study evaluating the prevalence of maternal GBS colonization were conducted. GBS isolates were tested for antimicrobial susceptibility, serotyped, and assessed for the appurtenance to the hypervirulent ST17 clone. RESULTS: Of 98 neonates with GBS, early-onset GBS disease (EOD) comprised 83.7 and 16.3% were late-onset GBS disease (LOD). The prevalence of maternal GBS colonization was 27%. All GBS isolates were susceptible to penicillin. Serotype III predominated (42.6%) for neonatal invasive infections. GBS isolates belonging to the ST17 sequence type were found only as serotype III. CONCLUSION: This study documents the frequency of GBS EOD, the high rate of maternal GBS colonization, and the predominance of the hypervirulent clone type III/ST17 in infants.

Nitratireductor luteus sp. nov. isolated from saline-alkali land.

The Gram-staining negative, oxidase and catalase negative strain KC-ST17T, isolated from saline-alkali land, was characterized using a polyphasic approach to determine its taxonomic position. Using 16S rRNA gene sequence analysis, the highest similarity of strain KC-ST17T was found with Nitratireductor pacificus CCTCC AB 209302T (97.2%). Cells are aerobic, non-motile, and rod-shaped. The isolate was found to be able to grow in NaCl concentrations of 0-4.0%. The assembled genome of strain KC-ST17T had a total length of 4.9 Mb with a G + C content of 62.7%. According to genome analysis, strain KC-ST17T encodes genes involved in the reduction of nitrate to nitrite, which may play a role in the utilization of nitrogenous compounds from the soil as an immediate source of energy. Based on the phenotypic characteristics and phylogenetic analysis, strain KC-ST17T was confirmed to represent a novel species in the Nitratireductor genus; thus, the name Nitratireductor luteus sp. nov. was proposed. The type strain of this species was KC-ST17T (= KCTC 92119T = MCCC 1K07309T).

Nosocomial outbreak linked to a flexible gastrointestinal endoscope contaminated with an amikacin-resistant ST17 clone of Pseudomonas aeruginosa.

Endoscope contamination is infrequent but can be the source of nosocomial infections and outbreaks. In August 2016, an unexpected increase in the incidence of amikacin-resistant P. aeruginosa isolates (AK-Pae) was observed at a tertiary care center in the south of Spain. An epidemiological and microbiological investigation (August-October 2016) was performed to explain this finding. Isolates from clinical and environmental samples (2 endoscopes used for retrograde cholangiopancreatography; ERCP) were identified by MALDI-TOF. Antimicrobial susceptibility testing was performed using the MicroScan system. Whole-Genome-Sequencing (Miseq, Illumina) was performed to determine the resistome and virulome. Clonal relatedness among isolates was assessed by SpeI-PFGE and MLST. A Caenorhabditis elegans killing assay was performed for virulence testing. Biofilm formation was performed using a colorimetric assay. Four of the 5 patients infected and/or colonized with AK-Pae in August 2016 had undergone ERCP ≤5 days before sample collection. Two endoscopes were contaminated with AK-Pae. Isolates from one endoscope showed an identical PFGE pattern to 9 isolates (cluster I) and differed (1-2 bands) to 5 isolates (cluster II). Isolates from these clusters belonged to the ST17 clone. This S17 clone was characterized by its low virulence in the C. elegans killing assay, and its biofilm-forming ability, slightly superior to that of high-risk clones of P. aeruginosa ST175 and ST235. This outbreak was caused by an endoscope used for ERCP contaminated with an invasive, moderately virulent, biofilm-forming AK-Pae ST17 clone, suggesting the possible emergence of a new high-risk lineage of this clone.

Molecular epidemiology of invasive and non-invasive group B Streptococcus circulating in Serbia.

Streptococcus agalactiae (group B Streptococcus, GBS) remains the leading cause of invasive diseases in neonates and an important cause of infections in the elderly. The aim of this study was to access the prevalence of GBS genito-rectal colonisation of pregnant women and to evaluate the genetic characteristics of invasive and non-invasive GBS isolates recovered throughout Serbia. A total of 432 GBS isolates were tested for antimicrobial susceptibility, capsular polysaccharide (CPS) types and the presence of the hvgA gene. One hundred one randomly selected isolates were further characterized by clustered regularly interspaced short palindromic repeats (CRISPRs) analysis and/or multilocus sequence typing (MLST). The prevalence of GBS colonization in pregnant women was 15%. Overall, six capsular types (Ia, Ib, II to V) were identified, the most common being III (32.2%) and V (25.2%). The hiper-virulent clone type III/ST17 was present in 43.1% and 6.3% (p < 0.05) of paediatric and adults isolates, respectively. Comparative sequence analysis of the CRISPR1 spacers content indicated that a few clones comprised the vast majority of the tested GBS isolates. Thus, it was estimated that dominant clones recovered from infants were CPS III/ST17 in late-onset infections (19/23; 82.6%), and Ia/ST23 in early-onset disease (44.4%). Conversely, genotype CPS V/ST1 was the most prevalent in adults (4/9; 25.4%). All isolates were susceptible to penicillin. Macrolide resistance (23.1%) was strongly associated with the ermB gene and constitutive resistance to clindamycin (63.9%). The majority of strains was resistant to tetracycline (86.6%), mostly mediated by the tetM gene (87.7%). GBS isolates of CPS V/ST1 and CPS III/ST23 were significantly associated with macrolide and tetracycline resistance, respectively. In conclusion, hyper-virulent CPS III/ST17 and V/ST1 were recognized as dominant GBS clones in this study.

High prevalence of group B streptococcus ST17 hypervirulent clone among non-pregnant patients from a Hungarian venereology clinic.

BACKGROUND: Although Streptococcus agalactiae is the leading causative agent of neonatal sepsis and meningitis, recently it is increasingly isolated from non-pregnant adults. The relation between its presence in the genitourinary tract and manifested clinical symptoms of STD patients remains an open question. In this study, a complex epidemiological investigation of GBS isolates from a venerology clinic was performed. METHODS: Ninety-six GBS isolates were serotyped and their genetic relatedness determined by PFGE. MLST was also performed for a subset of 20 isolates. The antibiotic susceptibility was tested with agar dilution. Surface proteins and the ST-17 hypervirulent clone was detected by PCR. RESULTS: The serotype prevalence was the following: V (29.2%), III (27.1%), Ia (22.9%), IV (10.4%), II (5.2%) and Ib (4.2%). A strong association was demonstrated between surface protein genes and serotypes. All isolates were fully susceptible to penicillin, but erythromycin and clindamycin resistance was high (41.7 and 35.4%, respectively), and 8 phenotypically macrolide sensitive isolates carried the ermB gene. 21.9% of all strains belonged to the hypervirulent ST17 clone, most being of serotype III and all were rib +. We found a few serotype IV isolates belonging to several STs and one serotype V/ST110 strain, containing a 44-bp deletion in the atr allele. CONCLUSIONS: The presence of silent ermB genes is of worry, as their expression upon macrolide exposure could lead to unforeseen therapeutic failure, while clindamycin is used for intrapartum antibiotic prophylaxis, in case of penicillin allergy. The other alarming result is the high prevalence of ST17 among these strains from STD patients, who could be sources of further infections. This is the first report from Hungary providing both serotyping and genotyping data of GBS isolates. These results could be helpful for vaccine production as the major vaccine candidates are capsular antigens or surface proteins.

Genomic Characterization of a Plasmid-Free and Highly Drug-Resistant Salmonella enterica Serovar Indiana Isolate in China.

The emergence of multi-drug resistant (MDR) Salmonella enterica serovar Indiana (S. Indiana) strains in China is commonly associated with the presence of one or more resistance plasmids harboring integrons pivotal in acquiring antimicrobial resistance (AMR). This study aims to elucidate the genetic makeup of this plasmid-free, highly drug-resistant S. Indiana S1467 strain. Genomic sequencing was performed using Illumina HiSeq 2500 sequencer and PacBio RS II System. Prodigal software predicted putative protein-coding sequences while BLASTP analysis was conducted. The S1467 genome comprises a circular 4,998,300 bp chromosome with an average GC content of 51.81%, encompassing 4709 open reading frames (ORFs). Fifty-four AMR genes were identified, conferring resistance across 16 AMR categories, aligning closely with the strain's antibiotic susceptibility profile. Genomic island prediction unveiled an approximately 51 kb genomic island housing a unique YeeVU toxin-antitoxin system (TAS), a rarity in Salmonella species. This suggests that the AMR gene cluster on the S1467 genomic island may stem from the integration of plasmids originating from other Enterobacteriaceae. This study contributes not only to the understanding of the genomic characteristics of a plasmid-free, highly drug-resistant S. Indiana strain but also sheds light on the intricate mechanisms underlying antimicrobial resistance. The implications of our findings extend to the broader context of horizontal gene transfer between bacterial species, emphasizing the need for continued surveillance and research to address the evolving challenges posed by drug-resistant pathogens.

Clonal expansion of Tn1546-like transposon-carrying vancomycin-resistant Enterococcus faecium, a nationwide study in Taiwan, 2004-2018.

OBJECTIVES: The prevalence of vancomycin-resistant Enterococcus faecium (VREfm) has increased significantly in Taiwan. We investigated the molecular epidemiology of clinical VREfm isolates to increase our understanding on their spread and changes in population structure over a 14-year span. METHODS: A total of 1113 E. faecium isolates were collected biennially from 2004 to 2018 in Taiwan. MICs were determined by broth microdilution. Whole-genome sequencing (WGS) was performed on 229 VREfm isolates to characterize their genetic environment of vancomycin resistance and wgMLST was used to investigate their clonal relationship. RESULTS: Among the 229 isolates, ST17 and ST78 predominated, especially during the later years, and their prevalences increased from 14.6% (7/48) and 25.0% (12/48) in 2004-2010 to 47.5% (87/181) and 29.8% (54/181) in 2012-2018, respectively. Four types of vanA-carrying Tn1546 variants were detected, with type 1 and type 2 predominated. Type 1 Tn1546 contained an addition of IS1251, while type 2 resembled type 1 but had an addition of IS1678. wgMLST revealed several distinct clusters of ST17 and ST78 isolates, with type 1 Tn1546-harbouring ST17-Cluster 16 being the largest and most widespread clones throughout the study years. Type 2 Tn1546-carrying ST78 became a predominant clone (Cluster 21) after 2012. Isolates within these clusters are highly similar despite being from different hospitals, regions, and study year. CONCLUSION: The increase of VREfm in Taiwan was attributed to horizontal transfer of vanA-carrying Tn1546 variants between different STs and spread of persistent clones. This study highlights the importance of integrating WGS into surveillance to combat antimicrobial resistance.

Within-patient and global evolutionary dynamics of Klebsiella pneumoniae ST17.

Klebsiella pneumoniae sequence type (ST) 17 is a global problem clone that causes multidrug-resistant (MDR) hospital infections worldwide. In 2008-2009, an outbreak of MDR ST17 occurred at a neonatal intensive care unit (NICU) in Stavanger, Norway. Fifty-seven children were colonized. We observed intestinal persistence of ST17 in all of the children for up to two years after hospital discharge. Here, we investigated the within-host evolution of ST17 in 45 of those children during long-term colonization and compared the outbreak with 254 global strains. Ninety-two outbreak-related isolates were whole-genome sequenced. They had capsule locus KL25, O locus O5 and carried yersiniabactin. During within-host colonization ST17 remained stable with few single nucleotide polymorphisms, no acquisition of antimicrobial resistance (AMR) or virulence determinants, and persistent carriage of a bla CTX-M-15-encoding IncFII(K) IncFIB(K) plasmid (pKp2177_1). The global collection included ST17 from 1993 to 2020 from 34 countries, that were from human infection (41.3%), colonization (39.3%) and respiratory specimens (7.3%), from animals (9.3%), and from the environment (2.7%). We estimate that ST17 emerged mid-to-late 19th century (1859, 95 % HPD 1763-1939) and diversified through recombinations of the K and O loci to form several sublineages, with various AMR genes, virulence loci and plasmids. There was limited evidence of persistence of AMR genes in any of these lineages. A globally disseminated sublineage with KL25/O5 accounted for 52.7 % of the genomes. It included a monophyletic subclade that emerged in the mid-1980s, which comprised the Stavanger NICU outbreak and 10 genomes from three other countries, which all carried pKp2177_1. The plasmid was also observed in a KL155/OL101 subclade from the 2000s. Three clonal expansions of ST17 were identified; all were healthcare-associated and carried either yersiniabactin and/or pKp2177_1. To conclude, ST17 is globally disseminated and associated with opportunistic hospital-acquired infections. It contributes to the burden of global MDR infections, but many diverse lineages persist without acquired AMR. We hypothesize that non-human sources and human colonization may play a crucial role for severe infections in vulnerable patients, such as preterm neonates.

Phylogenomic Analysis of Salmonella enterica Serovar Indiana ST17, an Emerging Multidrug-Resistant Clone in China.

Salmonella enterica serovar Indiana (S. Indiana) is an extremely expanded foodborne pathogen in China in recent years. This study aimed to elucidate the national prevalence and phylogenomic characterization of this pathogen in China. Among 5, 287 serotyped Salmonella isolates collected during 2002 to 2018, 466 S. Indiana isolates were found in 15 provinces, and 407 were identified to be ST17, and the rest were ST2040. Among 407 ST17 isolates, 372 (91.4%) were multidrug resistant, and 366 (89.9%) were resistant to ciprofloxacin, 235 (57.7%) were further resistant to ceftriaxone. Phylogenomic analysis revealed that ST17 isolates were classified into four clades (I, II, III and IV), which appeared in international clonal dissemination. ST17 isolates from China fell into Clade IV with part of isolates from the United Kingdom, the United States, South Korea, and Thailand, suggesting their close genetic relationship. Mutations in quinolone resistance-determining regions (QRDR) of GyrA and ParC, and plasmid-mediated quinolone resistance (PMQR) genes aac(6')-Ib-cr, oqxAB, and qnrS as well as extended spectrum ß-lactamases (ESBL) genes blaCTX-M, blaOXA, and blaTEM in isolates from Clade IV were much higher than those from other three clades. Various blaCTX-M subtypes (blaCTX-M-65, blaCTX-M-55, blaCTX-M-27, blaCTX-M-14, and blaCTX-M-123) with ISEcp1, IS903B, ISVsa5, and IS1R were found in ST17 isolates, especially Tn1721 containing ΔISEcp1-blaCTX-M-27-IS903B in P1-like bacteriophage plasmids. These findings on the prevalent and genomic characterization for the S. Indiana multidrug-resistant ST17 clone in China, which have not been reported yet, provide valuable insights into the potential risk of this high-resistant clone. IMPORTANCE Fluoroquinolones and cephalosporins are the primary choices for severe salmonellosis treatment. S. Indiana has become one of the most prevalent serovars in breeding poultry and poultry meats in China in recent years. ST17 was recognized as the leading epidemiological importance in S. Indiana because of its high-level resistance to the most of common antibiotics, including ciprofloxacin and ceftriaxone. However, the prevalence and phylogenomic characterization of ST17 isolates are unclear. Here, we did a retrospective screening on a large scale for S. Indiana in China, and performed its phylogenomic analysis. It was found that ST17 isolates had extensive spread in 15 provinces of China and became a multidrug-resistant clone. The international spread of the ST17 isolates was observed among several countries, especially China, the United Kingdom, and the United States. Our study emphasized the importance of surveillance of a high-resistant S. Indiana ST17 clone to combat its threat to public health.

Phenotypic and Genotypic Characterization of a Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae ST17-KL38 Clinical Isolate Harboring the Carbapenemase IMP-4.

Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) is a threat to global public health. We characterized a sequence type 17 (ST17) K. pneumoniae clinical isolate that was resistant to carbapenems and belonged to serotype KL38/O2. Its complete genome is comprised of a 5.1-Mb chromosome and two conjugative plasmids. The 52,578-bp N-type plasmid pXH210-IMP contains the blaIMP-4 carbapenemase gene and the quinolone resistance gene qnrS1. The 272,742-bp FII(K)-9:FIB(K)-10 plasmid pXH210-AMV carries an array of genes that confer resistance to aminoglycosides, chloramphenicol, quinolones, tetracycline, sulfonamides, trimethoprim, arsenic, copper, and silver. However, the XH210 genome otherwise lacks the genes that are considered characteristic markers of hypervirulence in K. pneumoniae. The virulence potential of XH210 was assessed using a random forest algorithm predictive model, as well as Galleria mellonella and mouse infection models. The results of these were concordant and suggested that XH210 is hypervirulent and therefore a CR-hvKP strain. This worrying convergence of virulence and clinically significant antibiotic resistance is particularly concerning given the absence of typical hypervirulence markers. Further investigations are required to understand the virulence mechanisms of XH210 and to improve the diagnostics of hypervirulent K. pneumoniae. IMPORTANCE The combination of drug resistance and hypervirulence significantly limits the available treatment options for life-threatening infections caused by multidrug-resistant hvKP, especially CR-hvKP. To date, research on IMP-producing CR-hvKP is extremely scarce, and the virulence mechanisms of CR-hvKP are far more complicated and diverse than has been described in the literature so far. In this study, we characterized the tigecycline-resistant and IMP-4 carbapenemase-producing ST17 K. pneumoniae isolate XH210 from a human blood sample. Importantly, XH210 exhibits hypervirulence but does not possess traits that are frequently associated with the phenotype, highlighting the urgent need to improve identification of potentially hypervirulent isolates and enhance active surveillance of CR-hvKP strains to prevent their dissemination.

Neonatal Group B Streptococcal Meningitis: Predictors for Poor Neurologic Outcome at 18 Months.

AIM: To find early predictors for poor neurodevelopmental outcome after neonatal group B streptococcal meningitis. METHODS: We retrospectively analyzed clinical characteristics of 23 patients with neonatal group B streptococcal meningitis and their neurodevelopmental outcome at 18 months. Available group B Streptococcus strains were serotyped and their genomes characterized. RESULTS: We found several differences between patients with early- (n = 5) and late-onset (n = 18) disease. Nine children had neurologic abnormalities at 18 months and 4 had epilepsy, all of them after late-onset disease. Most important risk factors for poor outcome were impaired consciousness at admission, hemodynamic instability, seizures, or abnormal electroencephalogram during the acute illness and abnormal neurologic and ophthalmologic examination at the end of treatment, whereas abnormalities in laboratory and imaging studies were not predictive. Hypervirulent serotype III, multilocus sequence type 17 group B Streptococcus was the predominant pathogen. CONCLUSIONS: Neurodevelopmental impairment after neonatal group B streptococcal meningitis is likelier in those with clinical and neurophysiological features indicating worse disease severity.

Whole-Genome Sequencing Enables Molecular Characterization of Non-Clonal Group 258 High-Risk Clones (ST13, ST17, ST147 and ST307) among Carbapenem-Resistant Klebsiella pneumoniae from a Tertiary University Hospital Centre in Portugal.

The carbapenem-resistant Enterobacterales (CRE) strains have been identified by the World Health Organization as critical priority pathogens in research and development of diagnostics, treatments, and vaccines. However, recent molecular information about carbapenem-resistant K. pneumoniae (CRK) epidemiology in Portugal is still scarce. Thus, this study aimed to provide the molecular epidemiology, resistome, and virulome of CRK clinical strains recovered from a tertiary care hospital centre (2019-2021) using polymerase chain reaction (PCR) and the advanced molecular technique whole-genome sequencing (WGS). PCR amplification of carbapenemase genes was performed in 437 carbapenem-resistant K. pneumoniae strains. The most frequent carbapenemases were: KPC-3 (42%), followed by OXA-181 (20%), GES-5 (0.2%), and NDM-1 (0.2%). Additionally, 10 strains (2%) coproduced KPC-3 and OXA-181, and 1 strain coproduced KPC-3 and OXA-48 (0.2%). The genomic population structure of 68 strains characterized by WGS demonstrated the ongoing dissemination of four main high-risk clones: ST13, ST17, ST147, and ST307, while no clones belonging to the European predominant clonal groups (CG15 and CG258) were found. Moreover, we describe one K. pneumoniae ST39-KL62 that coproduced the NDM-1 carbapenemase and the extended-spectrum beta-lactamase CTX-M-15, and one K. pneumoniae ST29-KL54 GES-5 and BEL-1 coproducer. Furthermore, a high prevalence of iron siderophores were present in all CRK strains, with several strains presenting both colibactin and the hypermucoviscosity phenotype. Thus, the data presented here highlight an uncommon molecular epidemiology pattern in Portugal when compared with most European countries, further supporting the emergence and dissemination of nonclonal group 258 hypervirulent multidrug high-risk clones and the need to promote in-depth hospital molecular surveillance studies.

Genomic insights on DNase production in Streptococcus agalactiae ST17 and ST19 strains.

Streptococcus agalactiae evasion from the human defense mechanisms has been linked to the production of DNases. These were proposed to contribute to the hypervirulence of S. agalactiae ST17/capsular-type III strains, mostly associated with neonatal meningitis. We performed a comparative genomic analysis between ST17 and ST19 human strains with different cell tropism and distinct DNase production phenotypes. All S. agalactiae ST17 strains, with the exception of 2211-04, were found to display DNase activity, while the opposite scenario was observed for ST19, where 1203-05 was the only DNase(+) strain. The analysis of the genetic variability of the seven genes putatively encoding secreted DNases in S. agalactiae revealed an exclusive amino acid change in the predicted signal peptide of GBS0661 (NucA) of the ST17 DNase(-), and an exclusive amino acid change alteration in GBS0609 of the ST19 DNase(+) strain. Further core-genome analysis identified some specificities (SNVs or indels) differentiating the DNase(-) ST17 2211-04 and the DNase(+) ST19 1203-05 from the remaining strains of each ST. The pan-genomic analysis evidenced an intact phage without homology in S. agalactiae and a transposon homologous to TnGBS2.3 in ST17 DNase(-) 2211-04; the transposon was also found in one ST17 DNase(+) strain, yet with a different site of insertion. A group of nine accessory genes were identified among all ST17 DNase(+) strains, including the Eco47II family restriction endonuclease and the C-5 cytosine-specific DNA methylase. None of these loci was found in any DNase(-) strain, which may suggest that these proteins might contribute to the lack of DNase activity. In summary, we provide novel insights on the genetic diversity between DNase(+) and DNase(-) strains, and identified genetic traits, namely specific mutations affecting predicted DNases (NucA and GBS0609) and differences in the accessory genome, that need further investigation as they may justify distinct DNase-related virulence phenotypes in S. agalactiae.

Carbapenem-resistant Enterobacterales colonization and subsequent infection in a neonatal intensive care unit in Shanghai, China.

BACKGROUND: Colonization has been reported to play an important role in carbapenem-resistant Enterobacterales (CRE) infection; however, the extent to which carriers develop clinical CRE infection and related risk factors in neonatal intensive care unit (NICU) patients is unclear. AIM: To investigate the frequency of CRE colonization and its contribution to infections in NICU patients. METHODS: CRE colonization screening and CRE infection surveillance were performed in the NICU in 2017 and 2018. FINDINGS: Among 1230 unique NICU patients who were screened for CRE colonization, 144 patients tested positive (11.7%, 144/1230), with 9.2% (110/1197) in the intestinal tract, which was higher than that in the upper respiratory tract (6.6%, 62/945) (P=0.026). Gestational age, low birth weight and prolonged hospitalization were risk factors for CRE colonization (all P<0.001). Diversilab homology monitoring found an overall 17.4% (25/144) risk of infection among patients colonized with CRE. For carbapenem-resistant Klebsiella pneumoniae (CR-KP) and carbapenem-resistant Escherichia coli (CR-ECO), the risks were 19.1% (21/110) and 13.8% (4/29), respectively. The independent risk factors for CR-KP clinical infection among CR-KP carriers were receiving mechanical ventilation (odds ratio (OR), 10.177; 95% confidence interval (CI), 2.667-38.830; P=0.013), a high level of neonatal nutritional risk assessment (OR, 0.251; 95% CI, 0.072-0.881; P=0.031) and a high neonatal acute physiology II (SNAP-II) score (OR, 0.256; 95% CI, 0.882-1.034; P=0.025). CONCLUSIONS: The colonization of CRE may increase the incidence of corresponding CRE infection in NICU patients. Receiving mechanical ventilation, malnutrition and critical conditions with high SNAP-II scores were independent risk factors for subsequent CR-KP clinical infection.

Unusual finding of the human-adapted hypervirulent serotype III/ST17 clone in a historical bovine Group B Streptococcus isolate from Brazil.

Group B Streptococcus (GBS) is a leading cause of human neonatal infections and bovine mastitis. We report here the unusual finding of the human-adapted hypervirulent serotype III/ST17 clone in a bovine GBS isolated in 1987 in Brazil. This isolate shared several phenotypic and genotypic characteristics with serotype III/ST17 strains obtained from human sources, including PFGE pattern, pilus genes, lactose fermentation, DNase activity, and antimicrobial susceptibility profile, highlighting the importance of continued tracking of GBS in the One Health scope. The study brings new evidence for the potential interspecies transmission and sheds new light into evolution aspects of the pathogen Group B Streptococcus (GBS) by reporting the occurrence of an ancient bovine GBS isolate belonging to a variant currently known to be exclusively found in human hosts.

Comparative genomic analysis and identification of pathogenicity islands of hypervirulent ST-17 Streptococcus agalactiae Brazilian strain.

Streptococcus agalactiae are important pathogenic bacteria that cause severe infections in humans, especially neonates. The mechanism by which ST-17 causes invasive infections than other STs is not well understood. In this study, we sequenced the first genome of a S. agalactiae ST-17 strain isolated in Brazil using the Illumina HiSeq 2500 technology. S. agalactiae GBS90356 ST-17 belongs to the capsular type III and was isolated from a neonatal with a fatal case of meningitis. The genome presented a size of 2.03 Mbp and a G + C content of 35.2%. S. agalactiae has 706 genes in its core genome and an open pan-genome with a size of 5.020 genes, suggesting a high genomic plasticity. GIPSy software was used to identify 10 Pathogenicity islands (PAIs) which corresponded to 15% of the genome size. IslandViewer4 corroborated the prediction of six PAIs. The pathogenicity islands showed important virulence factors genes for S. agalactiae e.g. neu, cps, dlt, fbs, cfb, lmb. SignalP detected 20 proteins with signal peptides among the 352 proteins found in PAIs, which 60% were located in the SagPAI_5. SagPAI_2 and 5 were mainly detected in ST-17 strains studied. Moreover, we identified 51 unique genes, 9 recombination regions and a large number of SNPs with an average of 760.3 polymorphisms, which can be related with high genomic plasticity and virulence during host-pathogen interactions. Our results showed implications for pathogenesis, evolution, concept of species and in silico analysis value to understand the epidemiology and genome plasticity of S. agalactiae.

Evaluation of the Results of Group B Streptococcus Screening by MALDI-TOF MS among Pregnant Women in a Hungarian Hospital.

Pregnant women colonized by Streptococcus agalactiae, or group B streptococcus (GBS), are at an increased risk of premature delivery and stillbirth, and their neonates can be endangered by the development of an invasive GBS disease. In this study, the results of the GBS screening among pregnant women performed between 2012 and 2018 (n = 19267) are presented. For the GBS positive samples, the antibiotic susceptibility of the isolated strains was also tested (n = 3554). During the examined period, the colonization rate varied between 17.4% and 19.8%. The overall rate of erythromycin and clindamycin resistance in the GBS positive samples was 34.9% and 34.6%, respectively. The frequency of the erythromycin and clindamycin resistant strains showed an increasing tendency. An analysis of the MALDI-TOF MS spectra of 260 GBS isolates revealed that 46.5% of them belonged to either the ST-1 or the ST-17 sequence types, indicating a high prevalence of these potentially invasive GBS strains in our region. More than half of the strains identified as ST-1 (52.1%) proved to be resistant to erythromycin and clindamycin.

Parallel Evolution of Group B Streptococcus Hypervirulent Clonal Complex 17 Unveils New Pathoadaptive Mutations.

Group B Streptococcus (GBS) is a commensal of the gastrointestinal and genitourinary tracts, while a prevailing cause of neonatal disease worldwide. Of the various clonal complexes (CCs), CC17 is overrepresented in GBS-infected newborns for reasons that are still largely unknown. Here, we report a comprehensive genomic analysis of 626 CC17 isolates collected worldwide, identifying the genetic traits behind their successful adaptation to humans and the underlying differences between carriage and clinical strains. Comparative analysis with 923 GBS genomes belonging to CC1, CC19, and CC23 revealed that the evolution of CC17 is distinct from that of other human-adapted lineages and recurrently targets functions related to nucleotide and amino acid metabolism, cell adhesion, regulation, and immune evasion. We show that the most distinctive features of disease-specific CC17 isolates were frequent mutations in the virulence-associated CovS and Stk1 kinases, underscoring the crucial role of the entire CovRS regulatory pathway in modulating the pathogenicity of GBS. Importantly, parallel and convergent evolution of major components of the bacterial cell envelope, such as the capsule biosynthesis operon, the pilus, and Rib, reflects adaptation to host immune pressures and should be taken into account in the ongoing development of a GBS vaccine. The presence of recurrent targets of evolution not previously implicated in virulence also opens the way for uncovering new functions involved in host colonization and GBS pathogenesis. IMPORTANCE The incidence of group B Streptococcus (GBS) neonatal disease continues to be a significant cause of concern worldwide. Strains belonging to clonal complex 17 (CC17) are the most frequently responsible for GBS infections in neonates, especially among late-onset disease cases. Therefore, we undertook the largest genomic study of GBS CC17 strains to date to decipher the genetic bases of their remarkable colonization and infection ability. We show that crucial functions involved in different steps of the colonization or infection process of GBS are distinctly mutated during the adaptation of CC17 to the human host. In particular, our results implicate the CovRS two-component regulator of virulence in the differentiation between carriage- and disease-associated isolates. Not only does this work raise important implications for the ongoing development of a vaccine against GBS but might also drive the discovery of key functions for GBS adaptation and pathogenesis that have been overlooked until now. Author Video: An author video summary of this article is available.

Early detection of OXA-370-producing Klebsiella pneumoniae ST17 co-harboring blaCTX-M-8 in Brazil.

We aimed to describe an early detection of OXA-370-producing Klebsiella pneumoniae in Brazil. The isolate CCBH10079 belonged to ST17 and the blaOXA-370 was located in a plasmid of ≅57kb.

High group B streptococcus carriage rates in pregnant women in a tertiary institution in Nigeria.

INTRODUCTION: In contrast to industrialized countries, until recently Group B Streptococcus (GBS) was infrequently reported in the developing world. This study was aimed at investigating the prevalence of GBS maternal colonization and to analyze the serotype distribution among the isolates. METHODS: Vagino-rectal swabs collected from pregnant women were cultured for GBS using conventional media. Swabs were also taken from the mouths, ears and umbilical stumps of the neonates born to colonized mothers. Multiplex PCR and a conventional PCR to discern the gbs2018-ST-17 gene (specific for sequence type(ST)-17 clone) was performed to characterize the Group B streptococcus isolates. RESULTS: A total of 300 pregnant women and 53 neonates were studied by culture but only 175 mothers by PCR. GBS was identified in four (6.8%) of 59 (19.7%) neonates of colonized mothers. Out of 175 mothers investigated by PCR, 112 (64%) were colonized. Serotype Ia (23.9%) was the most common among vagino-rectal isolates. Serotype II (71.4%) predominates among colonizing strain in newborns. A significant association between frequency of intercourse of > 2 per week and GBS carriage was found (t-test= 2.2; P value < 0.05). CONCLUSION: GBS carriage is high with low transmission. Strains that have been associated with GBS neonatal disease were reported, though in very low rates. Though none of the babies studied had invasive GBS disease, a more expansive study in the future will be required to establish if invasive GBS neonatal disease is uncommon in Nigeria.