Attitudes of pregnant women in the Dominican Republic towards a future maternal Group B Streptococcus vaccine.

INTRODUCTION: Current protocols aim to prevent some infant GBS infection through screening and peripartum antibiotics, however such strategies cannot be widely implemented in resource-limited settings. On the other hand, maternal vaccines in development against Group B Streptococcus (GBS) can provide a feasible universal approach. The success of any vaccine will depend on uptake in the population. Rates of maternal GBS colonization in the Dominican Republic (DR) and Caribbean region are among the highest in the world, but little is known about attitudes towards maternal vaccines in this region. METHODS: A cross-sectional, multicenter, mixed-methodology survey evaluated facilitators and barriers to maternal immunization and acceptability of a hypothetical Group B Streptococcus vaccine among pregnant women in three hospitals in the DR. RESULTS: Six-hundred and fifty women completed the survey of whom 85 % had never heard of GBS. Following receipt of information about GBS and a vaccine, 94 % of women stated that they would be likely or very likely to receive a vaccine. Being 18 years or younger was associated with a lower likelihood of GBS vaccine receipt (AOR 0.32, 95 % CI 0.14-0.69). Being born in the DR was associated with a higher likelihood of GBS vaccine receipt (AOR 2.73, 95 % CI 1.25-5.97). Among women who were unlikely to receive the vaccine, uncertainty about potential harm from a novel vaccine was the prominent theme elicited from free text responses. CONCLUSION: There was a high level of acceptance of a future GBS vaccine among this sample of pregnant women in the DR. However, knowledge of vaccines and vaccine-preventable diseases was low, and most women had concerns about the safety of new vaccines. Interventions that strengthen existing maternal immunisation infrastructures, including increasing education of pregnant women about vaccines, will aid the successful implementation of a future GBS vaccine.

Molecular characterization, antimicrobial resistance and invasion of epithelial cells by Streptococcus agalactiae strains isolated from colonized pregnant women and newborns in Rio de Janeiro, Brazil.

AIMS: To evaluate the prevalence, molecular characteristics, antimicrobial susceptibility, and epithelial invasion of Streptococcus agalactiae strains isolated from pregnant women and newborns in Rio de Janeiro, Brazil. METHODS AND RESULTS: A total of 67 S. agalactiae isolates, 48 isolates from pregnant women and 19 from neonates, were analyzed. Capsular type Ia and V were predominant (35.8%/each). The multilocus sequence typing analysis revealed the presence of 19 STs grouped into 6 clonal complexes with prevalence of CC17/40.3% and CC23/34.3%. The lmb and iag virulence genes were found in 100% of isolates. Four S. agalactiae strains, belonging to CC17/ST1249 and CC23/ST23, were able to adhere to A549 respiratory epithelial cells. Antimicrobial resistance was verified mainly to tetracycline (85%), erythromycin (70.8%), and clindamycin (58.3%). Four S. agalactiae isolates were multidrug resistant. The resistance genes tested were found in 92.5% of isolates for tetM, 58.2% for ermB, 28.4% for mefAE, and 10.4% for tetO. CONCLUSION: The study showed a high prevalence of virulence and antimicrobial genes in S. agalactiae strains isolated from pregnant women and newborns, supporting the idea that continued surveillance is necessary to identify risk factors and perform long-term follow-up in pregnant women and neonates in Rio de Janeiro.

Group B Streptococcus Sequence Type 103 as Human and Bovine Pathogen, Brazil.

Group B Streptococcus sequence type 103 is known primarily as a bovine mastitis pathogen. In Brazil, it has circulated in cattle and humans since the 1990s. It lacks scpB and, in humans, was found only among carriage isolates. Bovine-human interspecies transmission may have contributed to its evolution and spread.

Copaiba oil's bactericidal activity and its effects on health and zootechnical performance for Nile tilapia after oral supplementation.

Tilapia is one of the most important farmed fish in the world and the most cultivated in Brazil. The increase of this farming favors the appearance of diseases, including bacterial diseases. Therefore, the aim of this study was to evaluate the bactericidal activity of copaiba oil, Copaifera duckei, against Streptococcus agalactiae and Flavobacterium columnare and the dietary effect of copaiba oil on zootechnical performance, hematological, biochemical, immunological, and histological analysis before and after an intraperitoneal infection (body cavity) with S. agalactiae in Nile tilapia. For this, fish were randomly distributed into 15 fiber tanks in five treatments (0, 0.25, 0.50, 0.75, and 1.0%) and fed with a commercial diet supplemented with copaiba oil for 30 days. After this period, the fish were randomly redistributed for the experimental challenge with S. agalactiae into six treatments (T0, T1, T2, T3, T4, and T5), the fish were anesthetized, and blood samples were collected to assess hematological, biochemical, immunological, and histological parameters. Copaiba oil showed bactericidal activity against Streptococcus spp. and Flavobacterium spp. in vitro. In addition, concentrations of 0.75 and 1.0% of copaiba oil have an anti-inflammatory effect and improve hematological and immunological parameters, increasing leukocyte numbers, albumin, and serum lytic activity. Furthermore, there is an increase in the intestinal villus length and tissue damage in groups at concentrations of 0.75 and 1.0% of copaiba oil. In conclusion, copaiba oil presented bactericidal activity against Streptococcus spp. and Flavobacterium spp. in vitro, and oral supplementation at concentrations of 0.75 and 1.0% compared to the control group enhanced non-specific immune parameters and digestibility in Nile Tilapia.

Vaccines for Streptococcus agalactiae: current status and future perspectives.

A maternal vaccine to protect newborns against invasive Streptococcus agalactiae infection is a developing medical need. The vaccine should be offered during the third trimester of pregnancy and induce strong immune responses and placental transfer of protective antibodies. Polysaccharide vaccines against S. agalactiae conjugated to protein carriers are in advanced stages of development. Additionally, protein-based vaccines are also in development, showing great promise as they can provide protection regardless of serotype. Furthermore, safety concerns regarding a new vaccine are the main barriers identified. Here, we present vaccines in development and identified safety, cost, and efficacy concerns, especially in high-need, low-income countries.

Riesgo microbiológico de caries y factores predisponentes en mujeres gestantes / Microbiological caries risk and predisposing factors in pregnant women

La caries es una enfermedad multifactorial que afecta los tejidos duros del diente, con la evaluación del riesgo de caries es posible determinar la probabilidad de su incidencia durante un determinado periodo de tiempo. El objetivo consistió en determinar el estado de salud bucal en mujeres gestantes y su relación con factores de riesgo de caries. Se realizó un estudio descriptivo observacional clínico. La población estuvo constituida por mujeres gestantes que concurrieron al Hospital Ángela Llano de la cuidad de Corrientes para su atención. Se confeccionó una historia clínica y se determinó el estado de salud bucal y de riesgo de caries según protocolo CAMBRA. Para la carac- terización y descripción de los datos se utilizaron estadísticas univariadas. Los resultados alcanzados fueron: Índice de Caries de 4.5 a 6.5, en el índice de Placa la media ± DS 56,8% ± 39,9% Min: 28,5%/ Max: 90,9%. Respecto al valor de pH de 7,11 ±0,43, Min.: 7,00, Max.: 8,67. Flujo salival: media ± DS: 0,58ml/m ± 0,28 ml/m Min.:0,2 ml/m Max.: 0,62 ml/m; Edad promedio: 22años. Min.:18 Max.: 33 años. Recuento de Strepto- coccus mutans (SM) con periodo gestacional 1° y 2° trimestre, el conteo de bacterias: 2.3x105 +/- 3.2x 105 UFC/ml de saliva y 3° Trimestre el conteo de 1.2x 106 +/-2.02 x 106 UFC/ml de saliva. La presencia de SM puede aumentar considerable- mente el riesgo de caries, si los mecanismos de defen- sa del huésped no anulan la bacteria (AU)

Caries is a multifactorial disease that affects the hard tissues of the tooth. By evaluating the risk of caries, it is possible to determine the probability of its incidence during a certain period of time. The objective was to determine the oral health status of pregnant women and its relationship with caries risk factors. A clinical observational descriptive study was carried out. The population was made up of pregnant women who attended the Ángela Llano Hospital in the city of Corrientes for care. A clinical history was prepared, and the oral health status and caries risk were determined according to the CAMBRA protocol. Univariate statistics were used to characterize and describe the data. The results achieved were Caries Index from 4.5 to 6.5, in the Plaque index the mean ± SD 56.8% ± 39.9% Min: 28.5%/ Max: 90.9%. Regarding the pH value of 7.11 ±0.43, Min.: 7.00, Max.: 8.67. Salivary flow: mean ± SD: 0.58 ml/m ± 0.28 ml/m Min.: 0.2 ml/m Max.: 0.62 ml/m; Average age: 22 years. Min.:18 Max.: 33 years. Streptococcus mutans (SM) count with gestational period 1st and 2nd trimester, bacteria count: 2.3x105 +/- 3.2x 105 CFU/ml of saliva and 3rd Trimester count 1.2x 106 +/- 2.02 x 106 CFU/ml of saliva. The presence of SM can considerably increase the risk of caries, if the host defense mechanisms do not override the bacteria (AU)

Long-term healthcare utilisation, costs and quality of life after invasive group B Streptococcus disease: a cohort study in five low-income and middle-income countries.

INTRODUCTION: There are no published data on the long-term impact of invasive group B Streptococcus disease (iGBS) on economic costs or health-related quality of life (HRQoL) in low-income and middle-income countries. We assessed the impact of iGBS on healthcare utilisation, costs and HRQoL in Argentina, India, Kenya, Mozambique and South Africa. METHODS: Inpatient and outpatient visits, out-of-pocket (OOP) healthcare payments in the 12 months before study enrolment, and health-state utility of children and caregivers (using the EuroQol 5-Dimensions-3-Level) were collected from iGBS survivors and an unexposed cohort matched on site, age at recruitment and sex. We used logistic or Poisson regression for analysing healthcare utilisation and zero-inflated gamma regression models for family and health system costs. For HRQoL, we used a zero-inflated beta model of disutility pooled data. RESULTS: 161 iGBS-exposed and 439 unexposed children and young adults (age 1-20) were included in the analysis. Compared with unexposed participants, iGBS was associated with increased odds of any healthcare utilisation in India (adjusted OR 11.2, 95% CI 2.9 to 43.1) and Mozambique (6.8, 95% CI 2.2 to 21.1) and more frequent healthcare visits (adjusted incidence rate ratio (IRR) for India 1.7 (95% CI 1.4 to 2.2) and for Mozambique 6.0 (95% CI 3.2 to 11.2)). iGBS was also associated with more frequent days in inpatient care in India (adjusted IRR 4.0 (95% CI 2.3 to 6.8) and Kenya 6.4 (95% CI 2.9 to 14.3)). OOP payments were higher in the iGBS cohort in India (adjusted mean: Int$682.22 (95% CI Int$364.28 to Int$1000.16) vs Int$133.95 (95% CI Int$72.83 to Int$195.06)) and Argentina (Int$244.86 (95% CI Int$47.38 to Int$442.33) vs Int$52.38 (95% CI Int$-1.39 to Int$106.1)). For all remaining sites, differences were in the same direction but not statistically significant for almost all outcomes. Health-state disutility was higher in iGBS survivors (0.08, 0.04-0.13 vs 0.06, 0.02-0.10). CONCLUSION: The iGBS health and economic burden may persist for years after acute disease. Larger studies are needed for more robust estimates to inform the cost-effectiveness of iGBS prevention.

Development and performance evaluation of a qPCR-based assay for the fully automated detection of group B Streptococcus (GBS) on the Panther Fusion Open Access system.

Streptococcus agalactiae [group B Streptococcus (GBS)] poses a major threat as the primary cause of early-onset neonatal invasive disease, particularly when mothers are colonized rectovaginally. Although culture remains the gold standard for antepartum GBS screening, quantitative polymerase chain reaction (qPCR) offers advantages in terms of sensitivity and turnaround time. The aim of this study was to validate the clinical utility of an automated qPCR laboratory-developed test (LDT) for antepartum GBS screening using the Panther Fusion Open Access system (Hologic, California, USA). The LDT targeted a conserved region of the GBS surface immunogenic protein gene, demonstrating no cross-reactivity and high coverage (99.82%-99.99%). The limit of detection (LoD) was 118 CFU/mL. Comparison with commercial qPCR assays (Panther Fusion GBS and VIASURE Streptococcus B Real-Time) revealed an overall agreement of 99.7%, with a robust Cohen's kappa coefficient of 0.992. Testing of 285 rectovaginal swabs from pregnant women and 15 external quality assessment samples demonstrated exceptional diagnostic performance of the LDT, achieving a diagnostic sensitivity and specificity of 100%, underscoring its accuracy. Prevalence and predictive values were also determined to reinforce test reliability. Our research highlights the limitations of culture-based screening and supports the suitability of our qPCR-based LDT for GBS detection in a clinical setting.IMPORTANCERectovaginal colonization by GBS is a major risk factor for early-onset invasive neonatal disease. The most effective approach to reducing the incidence of early-onset disease (EOD) has been described as universal screening, involving assessment of GBS colonization status in late pregnancy and intrapartum antibiotic prophylaxis. Despite its turnaround time and sensitivity limitations, culture remains the gold standard method for GBS screening. However, nucleic acid amplification-based tests, such as qPCR, have been utilized due to their speed and high sensitivity and specificity. This study validated the clinical usefulness of an automated qPCR-LDT for antepartum GBS screening through the Panther Fusion Open Access system (Hologic). Our study addresses the critical need for more robust, sensitive, and rapid strategies for GBS screening in pregnant women that could favorably impact the incidence of EOD.

[Streptococcus suis meningitis]. / Meningitis por Streptococcus suis.

Streptococcus suis (S. suis) is a globally prevalent swine pathogen, capable of generating infections in humans who were in contact with the animal or its raw meat. Clinical manifestations range from asymptomatic cases to systemic involvement, with low mortality, but with the possibility of leaving definitive sequelae such as ataxia and hearing loss. There are few case reports, due to lack of knowledge of the disease and its atypical presentation. The objective of this article is to report the case of a man with an occupational history of contact with pigs, who was admitted for meningitis and in whom the isolation of S. suis was obtained in cerebrospinal fluid and paired blood cultures; He completed antibiotic treatment adjusted to bacterial sensitivity, and was left with mild hearing loss as a consequence.

Streptococcus suis (S. suis) es un patógeno porcino prevalente a nivel mundial, capaz de generar infecciones en humanos que estuvieron en contacto con el animal o la carne cruda del mismo. Las manifestaciones clínicas comprenden desde casos asintomáticos hasta compromiso sistémico, con una baja mortalidad, pero con la posibilidad de dejar secuelas definitivas como la ataxia e hipoacusia. Son pocos los reportes de casos, debido al desconocimiento de la enfermedad y a su forma atípica de presentación. El objetivo de este artículo es relatar el caso de un varón con antecedentes ocupacionales de contacto con porcinos, que ingresó por meningitis y en el cual se obtuvo el aislamiento de S. suis en líquido cefalorraquídeo y hemocultivos pareados; completó tratamiento antibiótico ajustado a la sensibilidad bacteriana, quedó con hipoacusia leve como secuela.

Streptococcus equi subsp. zooepidemicus: High molecular diversity of Argentinian strains isolated from mares with endometritis.

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is a mucosal commensal of the lower genital tract in horses and is the most isolated bacterium causing endometritis in mares. The aim of this study was to determine the molecular diversity of S. zooepidemicus obtained from endometritis in mares in Buenos Aires province, Argentina. Thirty isolates obtained from the uterus of mares in 2005 and 2017 were studied. The MLST scheme was applied to identify the Argentinian genotypes and the clonal relationships and patterns of evolutionary descent were identified using the eBURST algorithm - goeBURST. Twenty six different Sequence types (STs) were identified, being only 11 of them previously reported in horses and also, from several host species and tissues. The other 15 STs were reported in Argentinian reproductive strains of mares in our study for the first time. The genotypes obtained from uterus in Argentina were not evenly distributed when all the published S. zooepidemicus STs were analysed, thus, it was not possible to establish that the same lineage circulates in our equine population. The fact that the identified genotypes were also reported in other countries, diverse samples and host species suggest that there is not a host, and an anatomical niche adaptation. Finally, the isolation of the same genotype in the vagina/clitoris and the uterus of the same mare highlights the versatility of S. zooepidemicus and its role as an opportunistic pathogen.

Effects of supplementation with different zinc-based products on the growth and health of Nile tilapia.

Zinc is one of the essential microelements for the metabolism of animals. Zinc nanoparticles may have higher bioavailability due to their low specific surface area, facilitating absorption by fish. The present study aimed to evaluate the effects of supplementation with different zinc-based products on the growth and health of Nile tilapia Oreochromis niloticus. Zinc, in different sizes (nanoparticles or bulk) and forms (inorganic or organic), were used as a supplement in the tilapia diet at a dose of 15 mg kg feed-1 for 60 days. At the end of the feeding trial, production performance, hemato-immunological parameters, activity of antioxidant system enzymes, exposure to Streptococcus agalactiae and zinc concentration in the muscle were examined. After the bacterial challenge, the mean corpuscular hemoglobin concentration (MCHC) significantly increased in the fish treated with organic zinc, inorganic nano zinc, and organic nano zinc, while in the control group (inorganic zinc), MCHC remained unchanged. Regarding defense cells, dietary inorganic nano zinc increased the number of basophils (1.50 ± 1.10) compared to organic zinc (0.80 ± 0.90). Lymphocyte count increased after the challenge only in the organic zinc treatments (bulk and nanoparticles). Neutrophils decreased in the control (inorganic zinc) (2.20 ± 1.70) and inorganic nano zinc (2.60 ± 2.70) treatments after the challenge. When compared before and after the bacterial challenge, the plasma antimicrobial titer significantly increased after the bacterial challenge in all treatments. No significant differences were observed for total proteins, enzymes (SOD and CAT), cumulative survival and zinc deposition on fillet. In conclusion, organic zinc in nanoparticles or bulk size increased Nile tilapia innate defense during bacterial infection. However, the other parameters evaluated were not affected by zinc particle size or form (organic or inorganic), indicating that further evaluations should be conducted with organic zinc in nanoparticles or bulk size in the tilapia diet.

Streptococcus suis meningitis: An emerging zoonotic disease in Brazil.

Streptococcus suis has been widely reported as a pathogen in animals, especially pigs. In terms of human health implications, it has been characterized as a zoonosis associated with the consumption of pork products and occupational exposure, particularly in Southeast Asian countries. Here, we present a rare case of human S. suis infection in Brazil, diagnosed in an older adult swine farmer, a small rural producer residing in the semi-arid region of Bahia, Brazil.

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.

Angiotensin II and post-streptococcal glomerulonephritis.

BACKGROUND: Post-streptococcal glomerulonephritis (PSGN) is a consequence of the infection by group A beta-hemolytic streptococcus. During this infection, various immunological processes generated by streptococcal antigens are triggered, such as the induction of antibodies and immune complexes. This activation of the immune system involves both innate and acquired immunity. The immunological events that occur at the renal level lead to kidney damage with chronic renal failure as well as resolution of the pathological process (in most cases). Angiotensin II (Ang II) is a molecule with vasopressor and pro-inflammatory capacities, being an important factor in various inflammatory processes. During PSGN some events are defined that make Ang II conceivable as a molecule involved in the inflammatory processes during the disease. CONCLUSION: This review is focused on defining which reported events would be related to the presence of this hormone in PSGN.

High Incidence Rates of Early-onset Bacterial Sepsis in Infants Born in Two Brazilian Maternities: A 15-Year Retrospective Analysis.

BACKGROUND: Data on the burden and etiology of neonatal early-onset bacterial sepsis (EOBS) in low-to-middle-income countries are scarce. Surveillance is critical for optimizing prevention and treatment strategies. We aimed to estimate the incidence of EOBS in 2 large Brazilian cohorts of neonates. METHODS: Data were retrospectively obtained from 33,794 neonates born between 2009 and 2017 at low-risk (n = 17,981) and high-risk maternity centers (n = 15,813). Blood cultures were taken within 72 hours of life from neonates with perinatal risk factors for EOBS or suspected EOBS. A positive blood culture for a pathogenic microorganism and a compatible clinical evolution confirmed the diagnosis of EOBS. RESULTS: One-third of the infants born from high-risk and 18.5% from low-risk maternities were investigated for EOBS. Overall, EOBS was more incident in neonates born in the high-risk facilities [66 cases or 4.2/1000 (95% CI: 3.2-5.3)] than in the low-risk facilities [24 cases or 1.3/1000 (95% CI: 0.9-2.0)]. The incidence rate of EOBS increased with decreasing gestational age (<32 weeks: 20.5/1000; 32-36 weeks: 5.6/1000; ≥37 weeks: 1.5/1000). Group B Streptococcus (GBS) was the agent more frequently identified in high-risk and low-risk maternities: 1.8/1000 (95% CI: 1.1-2.4) and 0.4/1000 (95% CI: 0.2-0.9), respectively. EOBS's overall case fatality rate was 17.8% for all the agents and 22% for GBS. CONCLUSIONS: EOBS remains unacceptably high and is frequently fatal in preterm and term infants cared for in high- or low-risk maternities. Because GBS has emerged as the most frequent causative agent, preventive strategies are urgently needed.

Genotypic characterization of Streptococcus didelphis causative of fatal infection in white-eared opossums.

Streptococcus didelphis was once reported as related to severe infections in opossums. Thus, we present the first comprehensive whole-genome characterization of clinical S. didelphis strains isolated from white-eared opossums (Didelphis albiventris). Long-read whole-genome sequencing was performed using the MinION platform, which allowed the prediction of several genomic features. We observed that S. didelphis genomes harbor a cluster for streptolysin biosynthesis and a conserved genomic island with genes involved in transcriptional regulation (arlR) and transmembrane transport (bcrA). Antimicrobial resistance genes for several drug classes were found, including beta-lactam, which is the main antimicrobial class used in Streptococcus spp. infections; however, no phenotypical resistance was observed. In addition, we predicted the presence of 33 virulence factors in the analyzed genomes. High phylogenetic similarity was observed between clinical and reference strains, yet no clonality was suggested. We also proposed dnaN, gki, pros, and xpt as housekeeping candidates to be used in S. didelphis sequence typing. This is the first whole-genome characterization of S. didelphis, whose data provide important insights into its pathogenicity.

Antimicrobial resistance of Streptococcus uberis isolated from bovine mastitis: Systematic review and meta-analysis.

Streptococcus uberis is one of the most common pathogens associated with bovine mastitis, commonly treated with antimicrobials (AM), favoring the appearance of antimicrobial resistance (AMR). The objective of this work was to determine the proportion of phenotypic AMR among S. uberis isolated worldwide from bovine intramammary infections between the years 1983-2022, and to assess the variables associated by means of a systematic review and metanalysis. Sixty articles were eligible for quantitative review. Ninety-four independent studies were obtained. The antimicrobials evaluated in more S. uberis strains were penicillin (21,987 strains), oxacillin (21,727 strains), erythromycin (20,013 strains), and ampicillin (19,354 strains). Most of the studies included in this meta-analysis were from Europe (44), followed by America (25), Africa (10), Asia (10), and Oceania (5). Among the included articles, 22 were published from 1983 to 2006, 23 from 2007 to 2012, 25 from 2013 to 2015, and the remaining 24 after 2016. Penicillin, erythromycin, and tetracycline were the antimicrobials with >25 studies. Therefore, the following analyses were performed only for these antimicrobials, presenting a high heterogeneity index (I2). The variability observed for penicillin and tetracycline was only explained, partially, by continent of origin. The variability observed for erythromycin was not explained by any of the potential explanatory variables included in this study. The S. uberis proportion of resistance to antimicrobials is highly variable and probably influenced by many factors other than those studied in this meta-analysis, where it was not possible to inform a unique average proportion of resistance.

Streptococcus agalactiae virulence factors isolated from bovine mastitis and antibiotic treatment response.

AIMS: This study aims to characterize the virulence factors of Streptococcus agalactiae strains isolated from bovine mastitis and their potential association with the antibiotic treatment response. METHODS AND RESULTS: Four different profiles were identified among the 181 S. agalactiae strains using polymerase chain reaction, of which hyl B and cylE were found in 100% of the isolated strains, followed by cfb (99.5%), scpB (40.3%), and lmb (15.5%). The cell invasion assay showed that lmb-positive strains exhibited higher invasion ability than lmb-negative. There was a significant association (P = 0.018) between lmb gene and cows that required more than one treatment cycle. CONCLUSIONS: These results showed that intramammary infections caused by lmb-carrier S. agalactiae strains did not adequately respond to the antibiotics administered, likely because of the presence of this virulence factor, which potentially favours the cell invasion capacity of these strains.