RESUMO
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.
Assuntos
Infecções Estreptocócicas , Bovinos , Humanos , Brasil/epidemiologia , Animais , Infecções Estreptocócicas/microbiologia , Infecções Estreptocócicas/veterinária , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/transmissão , Streptococcus agalactiae/genética , Streptococcus agalactiae/classificação , Streptococcus agalactiae/isolamento & purificação , Feminino , Mastite Bovina/microbiologia , Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/epidemiologia , FilogeniaRESUMO
BACKGROUND: The 10-valent pneumococcal conjugate vaccine (PCV10) was introduced for childhood vaccination in Brazil's National Immunization Program in 2010. After nine years of PCV10 use, we investigated the carriage prevalence, capsular types, antimicrobial resistance and risk factors among children living in Niterói city, RJ, Brazil. METHODS: Between September and December 2019, we conducted a cross-sectional study and recruited children under 6 years of age. Antimicrobial susceptibility was evaluated by the disk-diffusion method and MICs to beta-lactams and macrolides were determined by E-test®. Capsular types were deduced by multiplex PCR. Logistic regression was used to predict risk factors for pneumococcal carriage. RESULTS: Seventy-five (17.4%) of the 430 children were pneumococcal carriers. The most frequent capsular types were 6C/D (14.7%), 11A/D (13.3%), and 23B (9.3%). PCV10 serotypes represented 5.3%. All isolates were susceptible to levofloxacin, linezolid, rifampicin, and vancomycin. Penicillin non-susceptible pneumococci (PNSP) made up 37.3%, with penicillin and ceftriaxone MICs ranging from 0.12 to 4.0 µg/ml and 0.064-4.0 µg/ml, respectively. Of the 19 (25.3%) erythromycin-resistant (ERY-R) isolates (macrolide MICs of 6 to >256 µg/ml), most had the cMLSB phenotype (84.2%) and carried the erm(B) gene (73.7%). We detected 17 (22.6%) multidrug-resistant (MDR) isolates, strongly associated with serotype 6C/D. Presence of any symptoms, chronic diseases, childcare center attendance, living with young siblings, slum residence, and unstable income were predictors of pneumococcal carriage. CONCLUSIONS: Long-term universal childhood use of PCV10 has nearly eliminated carriage with PCV10 serotypes, but the high frequency of MDR isolates, especially associated with serotype 6C/D, remains a concern. Replacing PCV10 with PCV13 should reduce the proportion of ERY-R isolates and PNSP by at least 14% and 18%, respectively.
Assuntos
Infecções Pneumocócicas , Humanos , Infecções Pneumocócicas/epidemiologia , Infecções Pneumocócicas/prevenção & controle , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Brasil/epidemiologia , Prevalência , Estudos Transversais , Farmacorresistência Bacteriana , Streptococcus pneumoniae , Vacinas Pneumocócicas , Sorogrupo , Penicilinas , Eritromicina , Portador Sadio/epidemiologia , Nasofaringe , Fatores de RiscoRESUMO
Optochin susceptibility testing is a major assay used for presumptive identification of Streptococcus pneumoniae. Still, atypical optochin-resistant (Optr) pneumococci have been reported and this phenotype has been attributed to nucleotide substitutions in the genes coding for the F0F1ATPase. While substitutions in the atpC gene (c-subunit of ATPase) are more common and better characterized, data on mutations in the atpA (a-subunit) are still limited. We have characterized five Optr isolates presenting alterations in the atpA (Trp206Cys in four isolates and Trp206Ser in one isolate), constituting the first report of such mutations in Brazil. Most of the Optr isolates consisted of heterogeneous populations. Except for Opt MICs and the nucleotide changes in the atpA gene, Optr and Opts subpopulations originating from the same culture had identical characteristics. In addition, we compared phenotypic and genetic characteristics of these atpA mutants with those of atpC mutants previously identified in Brazil. No structural alterations were detected among predicted proteins, regardless of mutations in the coding gene, suggesting that, despite the occurrence of mutations, protein structures tend to be highly conserved, ensuring their functionalities. Phylogenetic analysis revealed that atypical Optr strains are true pneumococci and Opt resistance does not represent any apparent selective advantage for clinical isolates.
Assuntos
Farmacorresistência Bacteriana/genética , Genes Bacterianos , Mutação/genética , Quinina/análogos & derivados , Streptococcus pneumoniae/efeitos dos fármacos , Sequência de Bases , Brasil , Simulação por Computador , Farmacorresistência Bacteriana/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Fenótipo , Filogenia , Subunidades Proteicas/química , Quinina/farmacologiaRESUMO
BACKGROUND: Streptococcus pneumoniae (S. pneumoniae) of serogroup 19 are mainly represented by serotypes 19A and 19F, which are associated with antimicrobial resistance and disease. The wzy gene, a component of the pneumococcal capsular locus, is the target to differentiate serotypes 19A and 19F by PCR-based capsular typing. In the last decade, allelic variants of the wzy19F gene have been described, leading to misinterpretation of capsular typing results. METHODS: A collection of 154 serotype 19F S. pneumoniae strains recovered from carriage and disease in Brazil was evaluated to identify and characterize wzy19F variant isolates. RESULTS: Eleven (7%) wzy19F variant isolates were detected and identified as belonging to ST810 (n = 10) or ST13673 (n = 1; single-locus variant of ST810). They were mostly recovered from diseased patients, susceptible to the antimicrobial agents tested (except for one multidrug-resistant strain) and did not harbor pili genes. Sequences of the wzy19F gene of these variants were identical to each other and to those previously described in Brazil, but slightly different from wzy19F variants identified in other countries. CONCLUSION: This study indicated that wzy19F variants present a geographically driven distribution and was the first to uncover phenotypic and genetic features of a wzy19F variant lineage occurring in Brazil since 1989.
Assuntos
Infecções Pneumocócicas/microbiologia , Streptococcus pneumoniae/classificação , Streptococcus pneumoniae/isolamento & purificação , Alelos , Infecções Assintomáticas , Cápsulas Bacterianas/classificação , Cápsulas Bacterianas/genética , Brasil , Proteínas de Transporte/genética , Portador Sadio/microbiologia , Feminino , Variação Genética , Humanos , Masculino , Tipagem de Sequências Multilocus , Reação em Cadeia da Polimerase , Sorogrupo , Sorotipagem , Streptococcus pneumoniae/genéticaRESUMO
Streptococcus pneumoniae remains a major agent of invasive diseases, especially in children and the elderly. The presence of pneumococcal capsule, pneumococcal surface protein A (PspA), and pilus type 1 (PI-1) and the ability of colony phase variation are assumed to play important roles in the virulence potential of this microorganism. Differences in the capsular polysaccharide allow the characterization of more than 90 pneumococcal serotypes; among them, serotype 14 and serogroup 9 stand out due to their prevalence in the pre- pneumococcal conjugate vaccine era and frequent association with penicillin non-susceptibility. Here we investigated the distribution of PI-1 and pspA genes and colony phase variants among 315 S. pneumoniae isolates belonging to serotype 14 and serogroup 9, recovered over 20 years in Brazil, and correlated these characteristics with penicillin susceptibility and genotype as determined by multilocus sequence typing. All strains were shown to carry pspA genes, with those of family 2 (pspA2) being the most common, and nearly half of the strains harbored P1-1 genes. The pspA gene family and the presence of PI-1 genes were conserved features among strains belonging to a given clone. A trend for increasing the occurrence of pspA2 and PI-1 genes over the period of investigation was observed, and it coincided with the dissemination of CC156 (Spain9V -3) clone in Brazil, suggesting a role for these virulence attributes in the establishment and the persistence of this successful clone. Opaque variant was the colony phenotype most frequently observed, regardless of clonal type. On the other hand, the transparent variant was more commonly associated with penicillin-non-susceptible pneumococci and with strains presenting evidence of recombination events involving the genes coding for polysaccharide capsule and PspA, suggesting that pneumococcal transparent variants may present a higher ability to acquire exogenous DNA. The results bring to light new information about the virulence potentials of serotype 14 and serogroup 9 S. pneumoniae isolates representing the major clones that have been associated with the emergence and the dissemination of antimicrobial resistance in our setting since the late 1980s.
RESUMO
BACKGROUND: The 13-valent pneumococcal conjugate vaccine (PCV13) has been commercially available in Brazil since 2010. We investigated the carriage prevalence, capsular types, and antimicrobial resistance among pneumococci isolated from children immunized with PCV13 in Brazil. METHODS: We analyzed 500 childrenâ¯<â¯6â¯years old attending public (nâ¯=â¯270) and private (nâ¯=â¯230) clinics in Niterói/RJ, Brazil, in 2014. We determined the antimicrobial susceptibility and capsular types for all isolates. RESULTS: Thirty-eight (7.6%) of 500 children had received at least one PCV13 dose. Since only two (0.7%) of 270 children at the public clinic were vaccinated with PCV13, major analyses focused on 36 (15.7%) of 230 children attending private clinics. Nine (25%) of 36 children were pneumococcal carriers. Characteristics associated with carriage were ageâ¯≥â¯2â¯years, cough/expectoration, and childcare center attendance (pâ¯≤â¯0.01). The capsular types found were 15B/C (nâ¯=â¯2), 6C, 11A/D, 16F, 23A, and 23F. Two isolates were non-typeable (NT). Three (33.3%) isolates were multidrug resistant. We found four (44.4%) penicillin non-susceptible pneumococci, with penicillin and ceftriaxone MICs ranging from 0.12 to 4.0⯵g/ml and 0.023-0.5⯵g/ml, respectively. We also detected two (22.2%) erythromycin-resistant isolates (MICs of 3.0 and 256⯵g/ml). CONCLUSIONS: Colonization with PCV13 serotype was rare among the vaccinated children. Increasing PCV13 coverage might help reduce the frequency of major serotypes currently associated with invasive pneumococcal diseases in Brazil, such as 3 and 19A. The isolation of multidrug-resistant serotype 6C and NT isolates in carriage, however, requires close monitoring.
Assuntos
Infecções Pneumocócicas/prevenção & controle , Vacinas Pneumocócicas/uso terapêutico , Streptococcus pneumoniae/patogenicidade , Brasil , Criança , Pré-Escolar , Farmacorresistência Bacteriana , Feminino , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Infecções Pneumocócicas/imunologia , Sorogrupo , Streptococcus pneumoniae/imunologia , Vacinas Conjugadas/uso terapêuticoRESUMO
Group B Streptococcus (GBS) carriage by pregnant women is the primary risk factor for early-onset GBS neonatal sepsis. Intrapartum antibiotic prophylaxis (IAP) can prevent this transmission route, and two main approaches are recommended to base the selection of pregnant women to be submitted to IAP: the risk-based and the culture-based strategies. In Brazil, compliance to such recommendations is poor, and not much is known about GBS carriage. In the present study, 3,647 pregnant women living in Rio de Janeiro State, Brazil, were screened for GBS anogenital colonization, over a period of 8 years (2008-2015). GBS was detected in 956 (26.2%) of them, and presence of vaginal discharge was the only trait associated with a higher risk for GBS colonization. Serotypes Ia (257; 37.3%) and II (137; 19.9%) were the most frequent among 689 (72.1% of the total) GBS isolates evaluated, followed by NT isolates (84; 12.1%), serotype Ib (77; 11.1%), V (63; 9.1%), III (47; 6.8%) and IV (24; 3.5%). Estimated coverage of major serotype-based GBS vaccines currently under clinical trials would vary from 65.2% to 84.3%. All 689 isolates tested were susceptible to ampicillin and vancomycin. Resistance to chloramphenicol, clindamycin, erythromycin, levofloxacin, and tetracycline was observed in 5% (35), 2% (14), 14% (97), 5% (35) and 86% (592) of the isolates, respectively. No significant fluctuations in colonization rates, serotype distribution and antimicrobial susceptibility profiles were observed throughout the period of time investigated. The culture-based approach for IAP recommendation showed to be the best choice for the population investigated when compared to the risk-based, since the first did not increase the number of pregnant women submitted to antibiotic therapy and covered a larger number of women who were actually colonized by GBS. The fact the not all isolates were available for additional characterization, and serotype IX antiserum was not available for testing represent limitations of this study. Nevertheless, to the best of our knowledge, this is the largest investigation on GBS carriage among pregnant women in Brazil up to date, and results are useful for improving GBS prevention and treatment strategies.
Assuntos
Complicações Infecciosas na Gravidez , Infecções Estreptocócicas , Streptococcus agalactiae , Adolescente , Adulto , Brasil/epidemiologia , Feminino , Humanos , Gravidez , Complicações Infecciosas na Gravidez/tratamento farmacológico , Complicações Infecciosas na Gravidez/epidemiologia , Complicações Infecciosas na Gravidez/microbiologia , Complicações Infecciosas na Gravidez/patologia , Fatores de Risco , Infecções Estreptocócicas/tratamento farmacológico , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/genética , Infecções Estreptocócicas/patologia , Streptococcus agalactiae/genética , Streptococcus agalactiae/isolamento & purificaçãoRESUMO
Objectives: To determine the population structure and change in drug resistance of pneumococci colonizing children before and after the introduction of the 10-valent and 13-valent pneumococcal conjugate vaccines (PCV10/13) in Brazil. Methods: We used MLST to analyse 256 pneumococcal isolates obtained from children aged <6 years before (2009-10; n = 125) and after (2014; n = 131) the introduction of the PCV10 and PCV13. Antimicrobial susceptibility and capsular types were previously determined. Results: We identified 97 different STs. Ninety (35.2%) isolates were related to international clones. The most frequent lineages were serogroup 6-CC724 (where CC stands for clonal complex) and the MDR serotype 6C-CC386 in the pre- and post-PCV10/13 periods, respectively. Penicillin-non-susceptible pneumococci (PNSP) formed 24% and 38.9% of the pre- and post-PCV10/13 isolates, respectively (P = 0.01). In the pre-PCV10/13 period, serotype 14-ST156 was the predominant penicillin-non-susceptible lineage, but it was not detected in the post-PCV10/13 period. Serotype 14-ST156 and serotype 19A-ST320 complex isolates had the highest penicillin and ceftriaxone MICs in the pre- and post-PCV10/13 periods, respectively. In turn, serotype 6C-CC386 comprised almost 30% of the PNSP and over 40% of the erythromycin-resistant isolates (MIC >256 mg/L) in the post-PCV10/13 period. Conclusions: Although PNSP strains were polyclonal, most resistant isolates belonged to a single genotype from each period. Higher erythromycin resistance prevalence (42%) in the post-PCV10/13 period was mainly attributed to MDR serotype 6C-CC386. Ongoing surveillance of pneumococcal clonal composition is important to evaluate PCV use outcomes and to identify factors other than PCVs that drive pneumococcal drug resistance evolution.
Assuntos
Variação Genética , Genótipo , Infecções Pneumocócicas/microbiologia , Infecções Pneumocócicas/prevenção & controle , Vacinas Pneumocócicas/administração & dosagem , Streptococcus pneumoniae/classificação , Antibacterianos , Brasil/epidemiologia , Pré-Escolar , Farmacorresistência Bacteriana , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Infecções Pneumocócicas/epidemiologia , Vacinas Pneumocócicas/imunologia , Prevalência , Sorogrupo , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/isolamento & purificaçãoRESUMO
Cancer and hematological malignancies constitute major comorbidities in enterococcal infections, but little is known about the characteristics of enterococci affecting cancer patients. The aim of this study was to characterize 132 enterococcal clinical isolates obtained from cancer patients attending a Cancer Reference Center in Brazil between April 2013 and March 2014. Susceptibility to 17 antimicrobial agents was assessed by disk diffusion method. Resistance and virulence genes were investigated by PCR. Multilocus sequence typing (MLST) was performed for selected Enterococcus faecalis and Enterococcus faecium isolates. The predominant species was E. faecalis (108 isolates), followed by E. faecium (18), Enterococcus gallinarum (3), Enterococcus avium (2) and Enterococcus durans (1). Multidrug-resistant (MDR) isolates made up 44.7%, but all isolates were susceptible to fosfomycin, linezolid and glycopeptides. The most prevalent genes associated with erythromycin- and tetracycline-non susceptible isolates were erm(B) (47/71; 66.2%) and tet(M) (24/68; 35.3%), respectively. High-level resistance (HLR) to gentamicin was found in 22 (16.7%) isolates and 13 (59.1%) of them carried the aac(6')-Ie-aph(2â³)-Ia gene. HLR to streptomycin was detected in 34 (25.8%) isolates, of which 15 (44.1%) isolates had the ant(6')-Ia gene. The most common virulence genes were gelE (48.9%), esp (30.5%) and asa1 (29.8%). MLST performed for 26 E. faecalis isolates revealed 18 different sequence-types (STs), with seven corresponding to novel STs (625, 626, 627, 628, 629, 630, and 635). On the other hand, nine of 10 E. faecium isolates analyzed by MLST belonged to a single clonal complex, comprised of mostly ST412, which emerged worldwide after mid-2000s, but also two novel STs (963 and 964). We detected major globally disseminated E. faecalis and E. faecium clonal complexes along with novel closely related STs, indicating the fitness and continuous evolution of these hospital-adapted lineages.