[Molecular characteristics and drug susceptibility analysis of Streptococcus agalactiae from respiratory specimen sources].

To study the carriage status of drug susceptibility, clonal complex groups, serotypes, surface proteins and virulence genes of Streptococcus agalactiae from respiratory specimen sources. A total of 35 strains of S.agalactiae meeting the criteria were collected from 3 hospitals in 2 locations, Tangshan and Jinan. The age span of the patients was 3 days-92 years, and the percentage of elderly patients≥60 years was 71.5%.The susceptibility to 9 antimicrobial drugs was measured and analyzed using the micro broth dilution method. The strains were 100.0% sensitive to penicillin, linezolid, vancomycin, and ceftriaxone; However, it exhibits high resistance rates to erythromycin, clindamycin and levofloxacin, at 97.1%, 85.7% and 82.9% respectively; and the resistance rates to tetracycline and chloramphenicol were 34.3% and 14.2%, respectively. Genome sequence determination and analysis showed that 16 resistance genes were detected in 35 strains, among which: macrolide and lincosamide resistance genes were mainly ermB, with a carrying rate of 74.2%; tetracycline resistance genes were mainly tetM, with a carrying rate of 25.7%; in addition, the mutation rates of the quinolone resistance determinants gyrA and parC were 88.5% and 85.7%, respectively. 35 strains belonged to 6 ST types and 4 clonal groups, with CC10/ST10 as the main one, accounting for 62.8%; they contained 4 serotypes of Ⅰb, Ⅱ, Ⅲ, and Ⅴ, as well as 1 untyped strain, with serotype Ⅰb as the main one, accounting for 65.7%. The strains carried three pilus types, PI1+PI2a, PI2a and PI2b types, respectively, and detected five surface proteins, alpha, alp1, rib, srr, and rdf_0594, and seven virulence factors, cba, cfb, cylE, fbsA, hylB, lmb, and pavA. Overall, S.agalactiae isolated from respiratory tract specimens is predominantly sourced from elderly patients, with CC10 strains being most prevalent. These strains harbor multiple drug-resistant and virulence genes, demonstrating elevated resistance rates to macrolides, lincosamides, and quinolones. This emphasizes the necessity for vigilant attention to the health threat posed by S. agalactiae from respiratory tract speciments of elderly patients.

Analysis of Differences in Neonatal Sepsis Caused by Streptococcus Agalactiae and Escherichia Coli.

BACKGROUND: Streptococcus agalactiae (GBS) and Escherichia coli (E. coli) are the main pathogenic bacteria in neonatal sepsis. Therefore, the clinical characteristics, nonspecific indicators, and drug susceptibilities of these two bacteria were studied. METHODS: In total, 81 and 80 children with sepsis caused by GBS and E. coli infection, respectively, admitted to the neonatal department of our hospital between May 2012 and July 2023, were selected, and the clinical characteris-tics of the two groups were analyzed. Nonspecific indicators and drug sensitivity test results were analyzed retrospectively. RESULTS: Birth weight, tachypnea, groan, tachycardia or bradycardia, and the incidence of complications, such as pneumonia, respiratory failure, and purulent meningitis, were higher in the GBS group than in the E. coli group. The children were born prematurely, and the mother had a premature rupture of membranes. The incidence of jaundice, abdominal distension, atypical clinical manifestations, and complications of necrotizing enterocolitis was lower than of the E. coli group, and the differences were statistically significant (p < 0.05). The WBC, NE#, NE#/LY#, hs-CRP, and PCT of the GBS group were higher than those of the E. coli group, whereas the MPV, D-D, and FDP levels were lower than those in the E. coli group. The differences were all statistically significant (p < 0.05). The 81-bead GBS had high resistance rates against tetracycline (95%), erythromycin (48.8%), and clindamycin (40%), and no strains resistant to vancomycin, linezolid, penicillin, or ampicillin appeared, whereas 80 strains of E. coli were more resistant to penicillin and third-generation cephalosporins, with the higher resistance rates to ampicillin (68.30%), trimethoprim/sulfamethoxazole (53.6%), and ciprofloxacin (42.90%). Resistance rates to carbapenems and aminoglycosides were extremely low. CONCLUSIONS: Both GBS and E. coli neonatal sepsis have specific clinical characteristics, especially in terms of clinical manifestations, complications, non-specific indicators, and drug resistance. Early identification is important for clinical diagnosis and treatment.

Ice nucleation active bacteria metabolites as antibiofilm agent to control Aeromonas hydrophila and Streptococcus agalactiae infections in Aquaculture.

OBJECTIVES: The aim of this study was to quantify and identify metabolites of Ice Nucleation Active (INA) bacteria as an anti-biofilm agent against biofilms of fish pathogens such as Aeromonas hydrophila and Streptococcus agalactiae. RESULTS: Ice nucleation active bacteria, which have the ability to catalyze ice nucleation, isolated from rainwater in previous studies, were used. All INA isolates were tested in several assays, including the antimicrobial test, which uses streptomycin as the positive control and none of the isolates were found positive in the antimicrobial test. As for the quorum quenching assay, it was found that four out of ten isolates were able to disturb the communication system in Chromobacterium violaceum wild type, which was used as the indicator bacteria. On the next assay, all ten isolates were tested for Biofilm Inhibition and Destruction and showed anti-biofilm activity with the highest percentage inhibition of 33.49% by isolate A40 against A. hydrophila and 77.26% by isolate A19 against S. agalactiae. C1 performed the highest destruction against A. hydrophila and S. agalactiae, with percentages of 32.11% and 51.88%, respectively. As for the GC-MS analysis, supernatants of INA bacteria contain bioactive compounds such as sarcosine and fatty acids, which are known to have antibiofilm activity against several biofilm-forming bacteria. Through 16s rRNA sequencing, identified bacteria are from the Pantoea, Enterobacter, and Acinetobacter genera. As for the conclusion, ice nucleation active bacteria metabolites tested showed positive results against pathogenic bacteria Aeromonas hydrophila and Streptococcus agalactiae in destructing and inhibiting biofilm growth.

Identification of antibiotic induced persister cells in Streptococcus agalactiae.

Antibiotic persistence is a phenomenon, where a small fraction of a bacterial population expresses a phenotypic variation that allows them to survive antibiotic treatment, which is lethal to the rest of the population. These cells are called persisters cells, and their occurrence has been associated with recurrent disease. Streptococcus agalactiae is a human pathobiont, able to cause invasive infections, and recurrent infections have been reported to occur in both newborns and adults. In this study, we demonstrated that S. agalactiae NEM316 can form persister cells when exposed to antibiotics from different classes. The frequency of persister cell formation was dependent on bacterial growth phase and the class of antibiotics. The ability to form persister cells in response to penicillin was shown to be a general trait among different clinical S. agalactiae isolates, independent of sero- and sequence-type. Taken together, this study shows the existence of antibiotic tolerant S. agalactiae persister cells, which may explain why this bacterial species frequently persists after treatment of invasive infection and can be associated with recurrent disease.

Genomic insights into the diversity, virulence, and antimicrobial resistance of group B Streptococcus clinical isolates from Saudi Arabia.

Introduction: Detailed assessment of the population structure of group B Streptococcus (GBS) among adults is still lacking in Saudi Arabia. Here we characterized a representative collection of isolates from colonized and infected adults. Methods: GBS isolates (n=89) were sequenced by Illumina and screened for virulence and antimicrobial resistance determinants. Genetic diversity was assessed by single nucleotide polymorphisms and core-genome MLST analyses. Results: Genome sequences revealed 28 sequence types (STs) and nine distinct serotypes, including uncommon serotypes VII and VIII. Majority of these STs (n=76) belonged to the human-associated clonal complexes (CCs) CC1 (33.71%), CC19 (25.84%), CC17 (11.24%), CC10/CC12 (7.87%), and CC452 (6.74%). Major CCs exhibited intra-lineage serotype diversity, except for the hypervirulent CC17, which exclusively expressed serotype III. Virulence profiling revealed that nearly all isolates (94.38%) carried at least one of the four alpha family protein genes (i.e., alphaC, alp1, alp2/3, and rib), and 92.13% expressed one of the two serine-rich repeat surface proteins Srr1 or Srr2. In addition, most isolates harbored the pilus island (PI)-2a alone (15.73%) or in combination with PI-1 (62.92%), and those carrying PI-2b alone (10.11%) belonged to CC17. Phylogenetic analysis grouped the sequenced isolates according to CCs and further subdivided them along with their serotypes. Overall, isolates across all CC1 phylogenetic clusters expressed Srr1 and carried the PI-1 and PI-2a loci, but differed in genes encoding the alpha-like proteins. CC19 clusters were dominated by the III/rib/srr1/PI-1+PI-2a (43.48%, 10/23) and V/alp1/srr1/PI-1+PI-2a (34.78%, 8/23) lineages, whereas most CC17 isolates (90%, 9/10) had the same III/rib/srr2/P1-2b genetic background. Interestingly, genes encoding the CC17-specific adhesins HvgA and Srr2 were detected in phylogenetically distant isolates belonging to ST1212, suggesting that other highly virulent strains might be circulating within the species. Resistance to macrolides and/or lincosamides across all major CCs (n=48) was associated with the acquisition of erm(B) (62.5%, 30/48), erm(A) (27.1%, 13/48), lsa(C) (8.3%, 4/48), and mef(A) (2.1%, 1/48) genes, whereas resistance to tetracycline was mainly mediated by presence of tet(M) (64.18%, 43/67) and tet(O) (20.9%, 14/67) alone or in combination (13.43%, 9/67). Discussion: These findings underscore the necessity for more rigorous characterization of GBS isolates causing infections.

Chlorella vulgaris algae ameliorates chlorpyrifos toxicity in Nile tilapia with special reference to antioxidant enzymes and Streptococcus agalactiae infection.

BACKGROUND: Chlorpyrifos (CPF) is a widely used pesticide in the production of plant crops. Despite rapid CPF biodegradation, fish were exposed to wastewater containing detectable residues. Recently, medicinal plants and algae were intensively used in aquaculture to replace antibiotics and ameliorate stress impacts. METHODS AND RESULTS: An indoor experiment was conducted to evaluate the deleterious impacts of CPF pollution on Nile tilapia health and the potential mitigation role of Chlorella vulgaris algae. Firstly, the median lethal concentration LC50 - 72 h of CPF was determined to be 85.8 µg /L in Nile tilapia (35.6 ± 0.5 g body weight) at a water temperature of 27.5 °C. Secondly, fish were exposed to 10% of LC50 - 72 h for six weeks, and tissue samples were collected and examined every two weeks. Also, Nile tilapia were experimentally infected with Streptococcus agalactiae. Exposed fish were immunosuppressed expressed with a decrease in gene expressions of interleukin (IL) 1ß, IL-10, and tumor necrosis factor (TNF)-α. Also, a decline was recorded in glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) gene expression in the head kidney tissue. A high mortality rate (MR) of 100% was recorded in fish exposed to CPF for six weeks and challenged with S. agalactiae. Fish that received dietary C. vulgaris could restore gene expression cytokines and antioxidants compared to the control. After six weeks of CPF exposure, fish suffered from anemia as red blood cell count (RBCs), hemoglobin (Hb), and packed cell volume (PCV) significantly declined along with downregulation of serum total protein (TP), globulin (GLO), and albumin (ALB). Liver enzymes were significantly upregulated in fish exposed to CPF pollution, alanine aminotransferase (ALT) (42.5, 53.3, and 61.7 IU/L) and aspartate aminotransferase (AST) (30.1, 31.2, and 22.8) after 2, 4, and 6 weeks, respectively. On S. agalactiae challenge, high MR was recorded in Nile tilapia exposed to CPF (G3) 60%, 60%, and 100% in week 2, week 4, and week 6, and C. vulgaris provided a relative protection level (RPL) of 0, 14.29, and 20%, respectively. CONCLUSIONS: It was concluded that CPF pollution induces immunosuppressed status, oxidative stress, and anemic signs in Nile tilapia. In contrast, C. vulgaris at a 50 g/kg fish feed dose could partially ameliorate such withdrawals, restoring normal physiological parameters.

Distributions of candidate vaccine Targets, virulence Factors, and resistance features of invasive group B Streptococcus using Whole-Genome Sequencing: A Multicenter, population-based surveillance study.

BACKGROUND: Group B Streptococcus (GBS) is a leading cause of morbidity and mortality in young infants worldwide. This study aimed to investigate candidate GBS vaccine targets, virulence factors, and antimicrobial resistance determinants. METHODS: We used whole-genome sequencing to characterize invasive GBS isolates from infants < 3 months of age obtained from a multicenter population-based study conducted from 2015 to 2021 in China. RESULTS: Overall, seven serotypes were detected from 278 GBS isolates, four (Ia, Ib, III, V) of which accounted for 97.8 %. We detected 30 sequence types (including 10 novel types) that were grouped into six clonal complexes (CCs: CC1, CC10, CC17, CC19, CC23 and CC651); three novel ST groups in CC17 were detected, and the rate of CC17, considered a hyperinvasive neonatal clone complex, was attached to 40.6 % (113/278). A total of 98.9 % (275/278) of isolates harbored at least one alpha-like protein gene. All GBS isolates contained at least one of three pilus backbone determinants and the pilus types PI-2b and PI-1 + PI-2a accounted for 79.8 % of the isolates. The 112 serotype III/CC17 GBS isolates were all positive for hvgA. Most of the isolates (75.2 %) were positive for serine-rich repeat glycoprotein determinants (srr1or srr2). Almost all isolates possessed cfb (99.6 %), c1IE (100 %), lmb (95.3 %) or pavA (100 %) gene. Seventy-seven percent of isolates harboured more than three antimicrobial resistance genes with 28.4 % (79/278) gyrA quinoloneresistancedeterminants mutation, 83.8 % (233/278) carrying tet cluster genes and 77.3 % (215/278) carrying erm genes which mediated fluoroquinolone, tetracycline and clindamycin resistance, respectively." CONCLUSIONS: The findings from this large whole-genome sequence of GBS isolates establish important baseline data required for further surveillance and evaluating the impact of future vaccine candidates.

Emergence of Group B Streptococcus Disease in Pigs and Porcupines, Italy.

We describe group B Streptococcus linked to disease in farmed pigs and wild porcupines in Italy. Occurrence in pigs was attributed to transmission from nonpasteurized bovine milk whey. Antimicrobial-resistance profiles in isolates from porcupines suggest no common source of infection. Our findings expand the known host range for group B Streptococcus disease.

Characterization of Lactococcus garvieae and Streptococcus agalactiae in cultured red tilapia Oreochromis sp. in Thailand.

OBJECTIVE: Acute mortality with clinical symptoms of streptococcal-like infections was observed in red tilapia Oreochromis sp. cultured in floating cages in Prachin Buri Province, Thailand, during May 2023. Herein, we identified an emerging pathogen, Lactococcus garvieae, as the etiological agent. METHODS: After bacterial isolation from the brain and kidney of diseased fish, identification was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and the VITEK 2 system. Sequencing of the 16S ribosomal RNA (rRNA) gene and phylogenetic analysis were applied to confirm bacterial species. Antimicrobial susceptibility testing was conducted. Histopathological findings in the brain, kidney, spleen, liver, and heart were evaluated. RESULT: From 20 fish samples, L. garvieae (n = 18 isolates) and Streptococcus agalactiae (n = 2 isolates) were identified. A phylogenetic tree of the 16S rRNA gene revealed that Thai isolates of either L. garvieae or S. agalactiae clustered with reference piscine isolates from intercontinental locations. Our isolates showed resistance against quinolones while being susceptible to other antimicrobials. Histopathological changes demonstrated severe septicemic conditions, with more invasive lesions-especially in the heart and liver-being apparent in L. garvieae-infected fish compared to S. agalactiae-infected fish. CONCLUSION: This study represents the first reported outbreak of L. garvieae with a concurrent S. agalactiae infection in farmed red tilapia in Thailand.

Macrolide resistance among Streptococcus agalactiae during COVID-19 public health emergency in Brazil.

During COVID-19 public health emergence, azithromycin was excessively used in Brazil, as part of a controversial "early treatment", recommended by former national health authorities. Excessive usage of macrolides may increase resistance rates among beta-hemolytic streptococci. Therefore, this study aimed to investigate the occurrence of resistance to erythromycin and clindamycin among Streptococcus agalactiae recovered from February 2020 to May 2023. Bacterial isolates (n = 116) were obtained from pregnant women and submitted to antimicrobial susceptibility testing, investigation of macrolide resistance phenotypes and genotypes, and identification of capsular type. The overall rate of erythromycin not susceptible (NS) isolates was 25.9%, while resistance to clindamycin was 5.2%. Drug efflux, associated with the M phenotype and mef(A) gene, was the prevalent mechanism of resistance (80%). Capsular type Ia was predominant (39.8%), followed by II, III, and V (17.7% each). A higher diversity of types was observed in the last years of the study. Type IV has had an increasing trend over time, being the fourth most common in 2023. The majority of the isolates that expressed the M phenotype presented capsular type Ia, while those with iMLS phenotype presented capsular type V. Despite no causal relationship can be established, azithromycin excessive usage may be a possible factor associated with this higher rate of erythromycin NS isolates, compared with most previous national studies. On the other hand, resistance to clindamycin has not changed significantly. Therefore, in the studied clinical setting, clindamycin remains a useful alternative to intrapartum prophylaxis among penicillin-allergic pregnant women.

Serotype distribution, virulence and antibiotic resistance of Streptococcus agalactiae isolated from cultured tilapia Oreochromis niloticus in Lake Volta, Ghana.

Streptococcus agalactiae infection is one of the major factors limiting the expansion of tilapia farming globally. In this study, we investigated the serotype distribution, virulence and antimicrobial resistance of S. agalactiae isolates from tilapia farmed in Lake Volta, Ghana. Isolates from 300 moribund fish were characterised by Gram staining, MALDI-TOF/MS and 16S rRNA sequencing. Serotype identification was based on multiplex polymerase chain reaction (PCR) amplification of the capsular polysaccharide genes. Detection of virulence genes (cfb, fbsA and cspA) and histopathology were used to infer the pathogenicity of the isolates. The susceptibility of isolates to antibiotics was tested using the Kirby-Bauer disk diffusion assay. All 32 isolates identified as S. agalactiae were of serotype Ia. This was notably different from isolates previously collected from the farms in 2017, which belonged to serotype Ib, suggesting a possible serotype replacement. The prevalence of the pathogen was related to the scale of farm operation, with large-scale farms showing higher S. agalactiae positivity. Data from histopathological analysis and PCR amplification of targeted virulence genes confirmed the virulence potential and ability of the isolates to cause systemic infection in tilapia. Except for gentamicin, the majority of the isolates were less resistant to the tested antibiotics. All isolates were fully sensitive to oxytetracycline, erythromycin, florfenicol, enrofloxacin, ampicillin and amoxicillin. This study has improved our understanding of the specific S. agalactiae serotypes circulating in Lake Volta and demonstrates the need for continuous monitoring to guide the use of antimicrobials and vaccines against streptococcal infections in Ghanaian aquaculture systems.

A decade of neonatal sepsis in Stockholm, Sweden: Gram-positive pathogens were four times as common as Gram-negatives.

PURPOSE: To assess Gram-positive bacterial (GPB) bloodstream infection (BSI) in neonates, covering incidence, morbidity, mortality, antimicrobial resistance patterns and biomarkers in Region Stockholm, Sweden between 2006 and 2016. METHODS: A population-based retrospective epidemiological study including infants with GPB-BSI, admitted to the neonatal units at Karolinska University Hospital (KUH). Data were collected from patient records, the Swedish Neonatal Quality Register, the microbiological laboratory at KUH and the Swedish Public Health Agency. RESULTS: We identified 357 infants with GPB-BSI, representing an incidence of 1.47/1000 live births (LB). Group B streptococcus (GBS) was the most common pathogen causing BSI in full-term infants and early-onset sepsis (EOS) (0.20/1000 LB), while coagulase-negative staphylococci (CoNS) were predominant in infants born very preterm and in late-onset sepsis (LOS) (0.79/1000 LB). There were no fatal GBS BSI cases, but 10.2% developed meningitis. The GPB case fatality rate was 9.5% and the sepsis fatality rate 2.8%. In GPB-BSI, 1/10 did not have an elevated C-reactive protein level. Staphylococcus aureus (S. aureus) BSI increased during the study period, but no methicillin or vancomycin resistant strains were found. The antimicrobial resistance (AMR) rate was highest in CoNS isolates. CONCLUSION: GPB-BSI was four times more common than Gram-negative BSI in neonates but resulted in lower mortality rate. GBS was the most common pathogen in full-term infants and in EOS. CoNS was the most common pathogen in LOS and infants born very preterm, and the AMR rate was high in these isolates. The increasing trend of S. aureus BSI indicates a need of further investigation.

Group B streptococcus in the Northern Territory in 2023: clindamycin down but not out.

Group B streptococcus (GBS) is a significant cause of perinatal morbidity and mortality; prophylactic antibiotics in the obstetric population can mitigate the risk of neonatal infection. The antibiotic of choice is penicillin; however, in women who have a penicillin hypersensitivity, clindamycin is the preferred agent. Worldwide resistance to clindamycin is rising in GBS isolates. In the Top End of the Northern Territory of Australia, we reviewed 113 GBS isolates in 2023. These GBS isolates revealed a 30% resistance to clindamycin. This rate has considerably increased since the Australia-wide survey published in 2011 where GBS resistance to clindamycin was quoted at 4.2%. As a result of this study, we are advocating for a change in practice in patients with known GBS resistance with penicillin hypersensitivity.

Antibacterial and anti-trichomunas characteristics of local landraces of Lawsonia inermis L.

BACKGROUND: Henna (Lawsonia inermis) with anti-bacterial properties has been widely used in traditional medicine especially Persian medicine. Henna oil is suggested for diseases of infectious origin, such as cervical ulcers. Group B Streptococcus agalactiae, Pseudomonas aeruginosa and, Trichomonas vaginalis are involved in the infection of women especially cervicitis. Henna grows in dry and tropical regions. The main important landraces of henna landraces are cultivated in Kerman, Sistan and Baluchestan, Hormozgan, and Bushehr provinces in Iran. Proper use of antimicrobial agents, use of new antimicrobial strategies, and alternative methods, such as herbal methods may help reduce drug resistance in the future. This study's objective was to investigate the anti-Trichomonas vaginalis activity of three different henna landraces and antimicrobial effects against group B Streptococcus agalactiae and, Pseudomonas aeruginosa. METHODS: Total phenol content was measured by Folin ciocaltu method. Antibacterial effect of landraces of Henna against P. aeruginosa and S. agalactiae were assayed by well diffusion method and minimal inhibitory concentration assessments were done using the broth micro-dilution technique. Anti-Trichomonas effect of Henna landraces were assayed by Hemocytometery method. RESULTS: Total phenol content of Shahdad, Rudbar-e-Jonub, and Qaleh Ganj was 206.51, 201.96, and 254.85 µg/ml, respectively. Shahdad, Rudbar-e-Jonub, and Qaleh Ganj had MIC against GBS at 15, 15 and, 4 µg/ml. The growth inhibition diameter of the most effective henna (Shahdad landrace) at a concentration of 20 µg/ml on P. aeruginosa was 2.46 ± 0.15 cm and in the MIC method at a concentration of 5 µg/ml of Shahdad landrace, P. aeruginosa did not grow. IC50 of shahdad Henna after 24 h, 48 h, and 72 h was 7.54, 4.83 and 20.54 µg/ml, respectively. IC50 of Rudbar-e-Jonub extract was 5.76, 3.79 and 5.77 µg/ml in different days. IC50 of Qaleh Ganj extract was 6.09, 4.08 and 5.74 µg/ml in different days. CONCLUSIONS: The amount of total phenol in Qaleh Ganj was higher than the other varieties. In the well diffusion method, Qaleh Ganj was more effective against group B Streptococcus (Gram-positive bacterium) than the other two landraces, and Shahdad landrace was more effective against P. aeruginosa (Gram-negative bacterium) than other. In the MIC method, the same result was obtained as in the well diffusion method, but at a lower concentration.

The antimicrobial activity of zinc against group B Streptococcus is strain-dependent across diverse sequence types, capsular serotypes, and invasive versus colonizing isolates.

BACKGROUND: Streptococcus agalactiae or Group B Streptococcus (GBS) is an encapsulated gram-positive bacterial pathobiont that commonly colonizes the lower gastrointestinal tract and reproductive tract of human hosts. This bacterium can infect the gravid reproductive tract and cause invasive infections of pregnant patients and neonates. Upon colonizing the reproductive tract, the bacterial cell is presented with numerous nutritional challenges imposed by the host. One strategy employed by the host innate immune system is intoxication of bacterial invaders with certain transition metals such as zinc. METHODOLOGY: Previous work has demonstrated that GBS must employ elegant strategies to circumnavigate zinc stress in order to survive in the vertebrate host. We assessed 30 strains of GBS from diverse isolation sources, capsular serotypes, and sequence types for susceptibility or resistance to zinc intoxication. RESULTS: Invasive strains, such as those isolated from early onset disease manifestations of GBS infection were significantly less susceptible to zinc toxicity than colonizing strains isolated from rectovaginal swabs of pregnant patients. Additionally, capsular type III (cpsIII) strains and the ST-17 and ST-19 strains exhibited the greatest resilience to zinc stress, whereas ST-1 and ST-12 strains as well as those possessing capsular type Ib (cpsIb) were more sensitive to zinc intoxication. Thus, this study demonstrates that the transition metal zinc possesses antimicrobial properties against a wide range of GBS strains, with isolation source, capsular serotype, and sequence type contributing to susceptibility or resistance to zinc stress.

Epidemiology of Invasive Infections Caused by Streptococcus agalactiae in Argentina.

In recent years, an increase in the number of cases of invasive infections due to Streptococcus agalactiae (group B Streptococcus [GBS]) in adults has been reported. During 2014 and 2015, a multicentric, observational, and prospective study, including 40 health centers, was developed to describe the phenotypic and genotypic characteristics of GBS isolates circulating in Argentina and to analyze the clinical and demographic characteristics of patients with invasive infections. We recovered 162 invasive (GBSi) isolates from adult patients (n = 130, 80.2%), neonates (n = 24, 15%), and children below 18 years of age (n = 8, 4.8%), and colonizing (GBSc) isolates were recovered in prenatal GBS screening. GBS infection in adults was associated with underlying diseases, mainly diabetes mellitus. All isolates were penicillin susceptible. Resistance rates to erythromycin (25%) and clindamycin (26%) among the GBSc isolates were significantly higher than those from GBSi strains (17.3% and 16.1%, respectively); by contrast, levofloxacin resistance was significantly higher in GBSi isolates (14.8% vs. 7%). Serotype Ia was the most frequent in neonates and Ib was most frequent in adults. Serotypes Ia and III were prevalent in GBSc isolates. The increase of levofloxacin resistance was associated with the presence of a serotype Ib clone. This work emphasizes the need for GBS infection surveillance studies to implement correct treatments and adequate prevention strategies.

Clinical and bacterial features of Group B streptococci with reduced penicillin susceptibility from respiratory specimens: a case-control study.

Streptococcus agalactiae (Group B Streptococcus, GBS) is an invasive pathogen that causes sepsis and meningitis among infants, elderly adults, and immunosuppressed patients. Generally, GBS is susceptible to penicillin; however, GBS with reduced penicillin susceptibility (PRGBS) has been reported. PRGBS are commonly isolated from respiratory specimens, but clinical features of patients with PRGBS remain unclear. In this case-control study, clinical features of patients with PRGBS and bacterial characteristics of these isolates from respiratory specimens were investigated. Patients with GBS at the University of the Ryukyus Hospital between January 2017 and June 2018 were retrospectively investigated. GBS were further classified into penicillin-susceptible GBS (PSGBS) and PRGBS using a drug susceptibility test. Moreover, serotypes, genotypes, and drug resistance genes of PRGBS isolates were determined. In total, 362 GBS were isolated, of which 46 were collected from respiratory specimens, which had the highest rate of PRGBS (24%). Compared to patients with PSGBS, those with PRGBS were more likely to have neuromuscular disease, poor performance status, risk of multidrug-resistant pathogen infection, prior pneumonia history within 1 year, and prior penicillin use within 1 year. Among eight PRGBS isolates, multilocus sequence typing revealed that five isolates were sequence type (ST) 358, two were ST3 and ST10, respectively, and one isolate was ST1404. All PRGBS isolates belonged to the ST1/ST19/ST10 group. This study reveals clinical characteristics of patients with PRGBS from respiratory specimens. Because invasive GBS infection cases are increasing, especially in the elderly, more attention should be paid to this infection.

Epidemiological Characterization of Group B Streptococcus Infections in Alberta, Canada: An Update from 2014 to 2020.

Group B Streptococcus (GBS) is a leading cause of invasive neonatal disease. Epidemiological surveillance of GBS is important to determine cumulative incidence, antimicrobial resistance rates, and maternal and neonatal disease prevention. In this study, we present an update on GBS epidemiology in Alberta, Canada, from 2014 to 2020. Over the 7-year period, 1,556 GBS isolates were submitted to the Alberta Public Health Laboratory for capsular polysaccharide (CPS) typing and antimicrobial susceptibility testing. We analyzed the distribution of CPS types in Alberta and found CPS types III (23.6%), Ia (16.0%), Ib (14.8%), II (13.3%), V (12.7%), IV (12.5%), and VI (2.38%) to be the most prevalent. Less than 1% each of CPS types VII, VIII, and IX were identified. In agreement with historical data, the presence of CPS type IV continued to rise across Alberta, particularly in cases of adult infection, where a 2-fold increase was observed. Cumulative incidences of GBS cases per 100,000 population and late-onset disease per 1,000 live births increased from 4.43 to 5.36 and 0.38 to 0.41, respectively, from 2014 to 2020. However, the incidence of early-onset disease decreased during the 7-year period from 0.2 to 0.07, suggestive of successful intrapartum chemoprophylaxis treatment programs. All GBS isolates were susceptible to penicillin and vancomycin. However, nonsusceptibility to erythromycin increased significantly, from 36.85% to 50.8%, from 2014 to 2020. Similarly, nonsusceptibility to clindamycin also increased significantly, from 21.0% to 45.8%. In comparison to historical data, the overall rates of GBS infection and antimicrobial resistance have increased and the predominant CPS types have changed. IMPORTANCE This work describes the epidemiology of invasive infections caused by the bacterium group B Streptococcus (GBS) in Alberta, Canada. We show that rates of invasive GBS disease have increased from 2014 to 2020 for both adult disease and late-onset disease in neonates, whereas the rate of early onset disease in neonates has decreased. We also show that the rate of resistance to erythromycin (an antibiotic used to treat GBS) has also increased in this time.

Clustered Regularly Interspaced Short Palindromic Repeat Analysis of Clonal Complex 17 Serotype III Group B Streptococcus Strains Causing Neonatal Invasive Diseases.

Group B Streptococcus (GBS) is an important pathogen of neonatal infections, and the clonal complex (CC)-17/serotype III GBS strain has emerged as the dominant strain. The clinical manifestations of CC17/III GBS sepsis may vary greatly but have not been well-investigated. A total of 103 CC17/III GBS isolates that caused neonatal invasive diseases were studied using a new approach based on clustered regularly interspaced short palindromic repeats (CRISPR) loci and restriction fragment length polymorphism (RFLP) analyses. All spacers of CRISPR loci were sequenced and analyzed with the clinical presentations. After CRISPR-RFLP analyses, a total of 11 different patterns were observed among the 103 CRISPR-positive GBS isolates. GBS isolates with the same RFLP patterns were found to have highly comparable spacer contents. Comparative sequence analysis of the CRISPR1 spacer content revealed that it is highly diverse and consistent with the dynamics of this system. A total of 29 of 43 (67.4%) spacers displayed homology to reported phage and plasmid DNA sequences. In addition, all CC17/III GBS isolates could be categorized into three subgroups based on the CRISPR-RFLP patterns and eBURST analysis. The CC17/III GBS isolates with a specific CRISPR-RFLP pattern were more significantly associated with occurrences of severe sepsis (57.1% vs. 29.3%, p = 0.012) and meningitis (50.0% vs. 20.8%, p = 0.009) than GBS isolates with RFLP lengths between 1000 and 1300 bp. Whole-genome sequencing was also performed to verify the differences between CC17/III GBS isolates with different CRISPR-RFLP patterns. We concluded that the CRISPR-RFLP analysis is potentially applicable to categorizing CC17/III GBS isolates, and a specific CRISPR-RFLP pattern could be used as a new biomarker to predict meningitis and illness severity after further verification.

Garlic: An Alternative Treatment for Group B Streptococcus.

Prenatal screening in pregnant women between 35 and 37 weeks of gestation and intrapartum antibiotic prophylaxis has successfully reduced the incidence of neonatal morbidity and mortality related to Streptococcus agalactiae. However, the contamination rates of newborns are still considerable. In traditional and folk medicines, it has been observed that garlic has been effective in treating S. agalactiae infection. The aim of this study was to isolate and identify the active compounds from garlic that have antimicrobial activity against S. agalactiae. In order to do this, SP80 (Sep-Pak 80%) obtained from crude garlic extract (CGE) was fractionated by reverse-phase ultrafast liquid chromatography with UV (RP-UFLC-UV) using a Shim-pack PREP-ODS column. All fractions obtained were tested using a microbial growth inhibition test against the S. agalactiae strain (ATCC 12386). Five clinical isolates were used to confirm the action of the fractions with antimicrobial activity, and the bacterial growth curve was determined. Identification of the antimicrobial compounds was carried out through liquid chromatography coupled with mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR). The active compounds found to exhibit antimicrobial activity were Ƴ-glutamyl-S-allyl-cysteine (fraction 18), Ƴ-glutamyl-phenylalanine (fraction 20), and the two stereoisomers (E and Z) of ajoene (fraction 42). The MICs of these fractions were 5.41 mg/ml, 4.60 mg/ml, and 0.16 mg/ml, respectively, and they inhibited the growth of the clinical isolates tested. Antimicrobial compounds from garlic may be a promising source in the search for new drugs against S. agalactiae. IMPORTANCE Invasive disease due to group B streptococcal (GBS) infection results in a wide spectrum of clinical disease in neonates. Maternal colonization by GBS is the primary risk factor for disease. The strategy recommended by the Centers for Disease Control to reduce neonatal GBS infection is the culture-based screening of all pregnant women at 35 to 37 weeks of gestation and intrapartum antibiotic prophylaxis (IAP). However, indiscriminate use of antibiotics favors the selection and spread of resistant bacteria. The global scenario of antibacterial resistance has been of great concern for public health, and natural products can be a source of new substances to help us grapple with this problem.