BackgroundStreptococcus pneumoniae remains a major cause of childhood morbidity and mortality worldwide. Nasopharyngeal colonization plays an important role in the development and transmission of pneumococcal diseases, and infants and young children are considered to be the main reservoir of this pathogen. The aim of this study was to evaluate the rates and characteristics associated with nasopharyngeal carriage, the distribution of serotypes and the antimicrobial resistance profiles of Streptococcus pneumoniae among children in a large metropolitan area in Brazil before the introduction of the 10-valent pneumococcal conjugate vaccine.MethodsBetween March and June 2010, nasopharyngeal swabs were collected from 242 children aged <6 years attending one day care center and the emergency room of a pediatric hospital. Pneumococcal isolates were identified by conventional methods and serotypes were determined by a sequential multiplex PCR assay and/or the Quellung reaction. The antimicrobial susceptibilities of the pneumococci were assessed by the disk diffusion method. MICs for erythromycin and penicillin were also performed. Erythromycin resistance genes were investigated by PCR.ResultsThe overall colonization rate was 49.2% and it was considerably higher among children in the day care center. Pneumococcal carriage was more common among day care attenders and cohabitants with young siblings. The most prevalent serotypes were 6B, 19F, 6A, 14, 15C and 23F, which accounted for 61.2% of the isolates. All isolates were susceptible to clindamycin, levofloxacin, rifampicin and vancomycin. The highest rate of non-susceptibility was observed for sulphamethoxazole-trimethoprim (51.2%). Penicillin non-susceptible pneumococci (PNSP) accounted for 27.3% of the isolates (MICs of 0.12-4 μg/ml). Penicillin non-susceptibility was strongly associated with serotypes 14 and 23F. Hospital attendance and the presence of respiratory or general symptoms were frequently associated with PNSP carriage. The two erythromycin-resistant isolates (MICs of 2 and 4 μg/ml) belonged to serotype 6A, presented the M phenotype and harbored the mef(A/E) gene.ConclusionsCorrelations between serotypes, settings and penicillin non-susceptibility were observed. Serotypes coverage projected for the 10-valent pneumococcal conjugate vaccine was low (45.5%), but pointed out the potential reduction of PNSP nasopharyngeal colonization by nearly 20%.

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Streptococcus agalactiae [β-haemolytic group B streptococci (GBS)] is a component of human intestinal and genitourinary microflora. This species is frequently related to illness in newborns, causing life-threatening diseases such as meningitis and bacteremia and is associated with complications during pregnancy and the post-partum period. GBS colonisation of the maternal genital tract has been considered the most important risk factor for neonatal disease development (Schuchat & Wenger 1994). GBS is also responsible for infections in older infants and non-pregnant adults, especially the elderly or those with any underlying medical conditions. Clinical manifestations include urinary tract infections, skin or soft tissue infections, osteomyelitis and bacteremia (Sendi et al. 2008). Points of concern include the increasing frequency of infections outside the perinatal period and a higher proportion of mortality in adults compared to the neonatal group (Phares et al. 2008).GBS has been continuously susceptible to penicillin and other β-lactams. However, resistance to antimicrobials used as alternative therapy, especially macrolides, lincosamides and fluoroquinolones has been documented in different countries (Duarte et al. 2005, Tazi et al. 2008, Pinheiro et al. 2009). One of the most common macrolide resistance mechanisms in streptococci is ribosomal modification by methylases, which are encoded by the erm genes. These enzymes also confer inducible or constitutive resistance to lincosamides and streptogramin B, which characterises macrolide-lincosamidestreptogramin B (MLS B ) phenotypes. Another common mechanism is drug efflux by a membrane-bound protein encoded by the mef gene, which is associated with the M phenotype (de Azavedo et al. 2001). Resistance to fluoroquinolones in GBS was first described in 2003 and is associated with point mutations in gyrA and parC genes (Kawamura et al. 2003).Despite the clinical impact of GBS infections and increasing resistance rates to some antimicrobials, there are a limited number of studies reporting antimicrobial resistance profiles among GBS strains circulating in Brazil, even from asymptomatic colonisation or clinical infection. In this study, 100 strains of S. agalactiae, isolated from genitourinary tract specimens from non-pregnant individuals during January 2008-August 2009 in the metropolitan area of Rio de Janeiro, were tested for antimicrobial susceptibility and the presence of macrolide resistance genes. The genetic diversity of erythromycin resistant isolates was evaluated using randomly amplified polymorphic-polymerase chain reaction (RAPD-PCR). SUBJECTS, MATERIALS AND METHODSStrains -One hundred S. agalactiae isolates from genitourinary tract specimens processed in a clinical laboratory in the metropolitan area of Rio de Janeiro during January 2008-August 2009 were included this study. The specimens [vaginal secretions (n = 49), urine (n = 30), sperm (n = 17) and other secretions (n = 4)] were obtained from non-pregnant individuals (73 females and 27 males, with ...

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