Nasopharyngeal carriage of Streptococcus pneumoniae among children in an urban setting in Brazil prior to PCV10 introduction.

Information on pneumococcal carriage in the pre-vaccine period is essential to predict and assess the impact of PCV in settings where disease surveillance is particularly difficult. Therefore, we present data on pneumococcal carriage before the introduction of the 10-valent-pneumococcal conjugate vaccine (PCV10) in Brazil. We conducted a prospective study on a cohort of 203 children aged <5 years old, randomly selected in an urban community located in the periphery of the city of Salvador, Brazil and followed them from January/2008 to January/2009. Nasopharyngeal swabs were collected from each child at four times. In total, 721 swabs were collected, yielding a pneumococcal carriage prevalence of 55% (n=398). In multivariate analyses, the variables associated with carriage were having contact with three or more children <2 years old (OR, 2.00; 95% CI 1.33-2.89) and living in a house with an average of 3 residents per room (OR, 1.77; 95% CI 1.05-3.10). Also, white participants were more likely to be protected from colonization (OR, 0.52; 95% CI 0.29-0.93), and prevalence of carriage varied over time, with lower prevalence occurring from February to June (OR, 0.53; 95% CI 0.37-0.78) compared to July to January. Contact with children under 2 years of age and living in crowded housing also were associated with colonization by highly invasive serotypes, although this relationship was not significant. The most prevalent vaccine serotypes were 6A/B (25.4%), 19F (10.1%) and 14 (9.0%), while the most prevalent non-vaccine serotypes were 16F (4.8%), 15B/C (4.5%) and 6C/D (3.5%). Overall, 38.4% (153/398) of the isolates were non-susceptible to penicillin, and of those, 73.8% (113/153) were non-susceptible to trimethoprim/sulfamethoxazole. Colonization rate by PCV10 serotypes was 52.2%. Routine PCV10 vaccination can lead to significant changes in pneumococcal serotypes found in NP colonization, indicating a need for continued monitoring, especially in crowded settings, as occurs in Brazil's slums.

Temporal trends and clonal diversity of penicillin non-susceptible pneumococci from meningitis cases from 1996 to 2012, in Salvador, Brazil.

BACKGROUND: Hospital-based surveillance for pneumococcal meningitis has been conducted since January 1996 in the city of Salvador, Brazil. The purpose of this study was to describe the temporal evolution of Penicillin Non-Susceptible Streptococcus pneumoniae (PNSSP) in regards to serotype distributions and clonal diversity recovered from meningitis cases over 17 years. METHODS: Broth microdilution was used to identify pneumococcal isolates that were PNSSP (Minimum Inhibitory Concentration > 0.12 µg/ml). The annual incidence rate of meningitis cases was calculated. Serotyping was defined using multiplex polymerase chain reaction assays and quellung reaction. Genetic diversity of PNSSP isolates was assessed using both pulsed-field gel electrophoresis (PFGE) and Multilocus Sequence Typing (MLST) analyses. RESULTS: A total of 854 cerebrospinal fluid (CSF) culture pneumococcal isolates were tested by broth microdilution method and serotyped. A total of 173 (20.3%) were penicillin non-susceptible (PNSSP) (Minimum Inhibitory concentration ≥ 0.12 µg/ml). The annual incidence of meningitis cases declined from 1.65/100,000 population (1996) to 0.2/100,000 population in 2012 and the rate due to PNSSP declined 82% over the 17-years of surveillance. PNSSP isolates were restricted to 13 serotypes, being the most common ones serotypes 14 (45.1%; 78/173), 23 F (19.1%; 33/173), 6B (14.4%; 25/173), 19 F (9.2%; 16/173) and 19A (5.2%; 9/173). Among the PNSSP isolates, 94% had serotypes represented in the 10-valent conjugate vaccine (PCV10). The predominant serotype 14 clonal groups were identified as PFGE group A/multilocus sequence type 66 (ST66) [35.3% (61/173)] and PFGE group GK/ST156 [4.6% (8/173)], the latter one associated with high level resistance to penicillin and ceftriaxone. CONCLUSIONS: Our results show sustained reductions in pneumococcal meningitis cases in the Metropolitan region of Salvador from 1996 to 2012. This might reflect a beneficial impact of conjugate vaccines. Continued surveillance and further studies need to be conducted to better understanding on PCV10 vaccine impact.

Serotype and genotype distributions of pneumococcal carriage isolates recovered from Brazilian children attending day-care centres.

Pneumococcal nasopharyngeal carriage isolates recovered from Brazilian children attending day-care centres in 2005 were assessed for serotype, genotype and penicillin susceptibility phenotype. As 124 of the 253 isolates (49 %) were characterized previously with respect to serotype and penicillin susceptibility, the primary objectives were to examine clonal associations and penicillin susceptibility within major serotypes and to assess the suitability of conventional multiplex PCR for deducing carriage serotypes within this population. Using a combination of PCR-based serotyping and the Quellung reaction, serotypes were identified for 81 % (205/253) of the isolates, with serogroups or types 14, 6, 23F, 19F and 18 being predominant. Included within the 205 isolates successfully serotyped by PCR were 28 isolates that had become non-viable. Forty-eight isolates were non-typable using both the PCR method and the Quellung reaction. Penicillin non-susceptibility was observed within 16 of the 18 multilocus sequence types detected. Thus, this study provides further evidence from a diverse collection of pneumococcal clones that PCR-based serotype deduction is useful for providing supportive evidence for pneumococcal conjugate vaccine implementation.

Serotype distribution and antimicrobial resistance of Streptococcus pneumoniae prior to introduction of the 10-valent pneumococcal conjugate vaccine in Brazil, 2000-2007.

This study describes the serotype distribution and antibiotic resistance patterns among 397 S. pneumoniae meningitis case isolates recovered in Salvador, Brazil, during the period of 2000-2007, before introduction of the 10-valent pneumococcal conjugate vaccine. The active hospital-based surveillance showed a decline in the annual incidence rates of pneumococcal meningitis during the period of study, from 1.12 cases to 0.83 cases/100,000 persons for all age groups (P<0.001), with an overall case-fatality rate of 28.6% (113 of 395) for all patients and 41.9% (57 of 136) for those <5 years of age. Serotypes 14 (n=55; 13.9%), 3 (n=32; 8.1%), 23F (n=32; 8.1%), 19F (n=31; 7.8%), 6B (n=30; 7.6%), 18C (n=28; 7.1%), and 6A (n=20; 5%) were the most prevalent serotypes. In patients <5 years the estimated projected coverage of 7-, 10- and 13-valent conjugate vaccines was 74.3%, 75.7% and 83.1%, respectively. Antimicrobial susceptibility testing revealed that 22.1% (n=88) of isolates were non-susceptible to penicillin, 56% were non-susceptible to trimethoprim/sulphamethoxazole, and 29.6% were non-susceptible to tetracycline. Nonsusceptibility to penicillin and cefotaxime was detected solely among serotype 14 isolates (n=4; 1%). This study provides an important baseline to assess the impact of conjugate vaccine implantation on the epidemiology of meningitis due to Streptococcus pneumoniae in Salvador, Brazil.

Prevalence of Streptococcus pneumoniae serotype 6C among invasive and carriage isolates in metropolitan Salvador, Brazil, from 1996 to 2007.

The newly described Streptococcus pneumoniae serotype 6C accounted for 2.3% (16/709) of meningitis cases and 3.2% (3/95) of nasopharyngeal isolates from healthy individuals in Brazil. The strains were multidrug resistant (18.8%) and genetically diverse. Despite low serotype 6C prevalence, continuous surveillance is necessary to guide vaccine strategies.

Diversity of mutations in the atpC gene coding for the c Subunit of F0F1 ATPase in clinical isolates of optochin-resistant Streptococcus pneumoniae from Brazil.

We report the characteristics of four optochin-resistant (Opt(r)) Streptococcus pneumoniae isolates from Brazil. All four Opt(r) isolates presented mutations in the nucleotide sequence coding for the c subunit of F(0)F(1) ATPase. Two isolates showed mutations in codons 23 (leading to the deduced amino acid substitution isoleucine instead of alanine) and 49 (serine instead of alanine, a novel type of mutation detected at this position), respectively. Two additional novel mutations, both located in codon 45, were detected in the other two isolates, corresponding to leucine or valine (instead of phenylalanine). The data indicate that three previously unrecognized alterations were detected in the atpC gene of S. pneumoniae and that Opt resistance among Brazilian pneumococcal isolates is not related to a specific pneumococcal serotype, antimicrobial-resistance profile, or clonal group.

Occurrence and Characteristics of Erythromycin-Resistant Streptococcus pneumoniae Strains Isolated in Three Major Brazilian States.

We investigated the occurrence and phenotypic and genotypic characteristics of erythromycin-resistant Streptococcus pneumoniae strains isolated in three major states in Brazil, from 1990 to 1999. Of the 931 pneumococcal strains evaluated, 40 (4.3%) were erythromycin-resistant (Ery-R). Among the 40 Ery-R strains, 90.0%, 80.0%, 27.5%, 5.0%, and 2.5% were resistant to tetracycline, trimethoprim-sulfamethoxazole, penicillin, chloramphenicol, and rifampin, respectively. None of the strains were resistant to ofloxacin or to vancomycin. Most [37 (92.5%)] of the 40 Ery-R isolates presented the MLS(B) phenotype and 3 (7.5%) strains showed the M phenotype. PCR testing indicated that all MLS(B) phenotype isolates harbored the erm(B) gene only, whereas the mef(A/E) gene was present in all isolates presenting the M phenotype. The tet(M) gene was the most frequent (86.1%) among Ery-R isolates that were also resistant to tetracycline. Pulsed-field gel electrophoresis (PFGE) analysis after SmaI digestion revealed the occurrence of clonal relationships within groups of strains belonging to serotypes 14, 19A, and 23F. All Ery-R isolates belonging to serotype 14 were susceptible to penicillin and were included in a single clonal group (named Ery(14)-A) related to the England(14-)9 internationally spread clone.

Phenotypic and genotypic characterization of clinical and intestinal enterococci isolated from inpatients and outpatients in two Brazilian hospitals.

The phenotypic and genotypic characteristics of clinical and intestinal enterococcal isolates recovered from inpatients and outpatients of two Brazilian hospitals, located in Niterói city, Rio de Janeiro, Brazil, were compared. A total of 601 strains were studied, including 253 isolated from different clinical sources and 348 intestinal strains (205 isolated from inpatients and 143 from outpatients) recovered from fecal specimens. Isolates were identified by using conventional physiological tests and evaluated for high-level resistance to aminoglycosides (HLR-A) and resistance to vancomycin and ampicillin by the agar screening technique. Susceptibility to several antimicrobial agents was evaluated by the disk diffusion method. The genetic diversity of Enterococcus faecalis strains presenting HLR-A was assessed by pulsed-field gel electrophoresis of chromosomal DNA after SmaI digestion. E. faecalis was the most frequent species among clinical isolates (90.1%) and intestinal strains from inpatients (53.6%). E. casseliflavus was the prevalent species among intestinal isolates from outpatients (35.0%). Clinical isolates were shown to be resistant to erythromycin (53.0%), tetracycline (52.2%), ciprofloxacin (36.4%), gentamicin (36.4%), streptomycin (30.4%), chloramphenicol (34.4%), norfloxacin (32.0%), imipenem (3.2%), and ampicillin (2.8%). Vancomycin resistance was only detected in intrinsic vancomycin-resistant enterococcal species. The overall prevalence of HLR-A was 52.2% among clinical isolates and 40.5% among intestinal strains. However, HLR-A was significantly more frequent among intestinal strains obtained from inpatients (56.6%) than among strains from outpatients (17.5%). Three major clonal groups were found among E. faecalis strains exhibiting HLR-GE or HLR-GE/ST (clonal groups GE-A and GE-B), and strains exhibiting HLR-ST (clonal group ST-A). HLR-A, particularly HLR-GE, was most frequently associated with enterococcal strains of nosocomial origin. Isolates included in the major clonal groups were recovered from clinical and intestinal sources from patients in both hospitals, indicating both intrahospital and interhospital spread of strains.

Infection due to extended-spectrum beta-lactamase-producing Salmonella enterica subsp. enterica serotype infantis in a neonatal unit.

OBJECTIVE: To describe the investigation and control of an outbreak of extended-spectrum beta-lactamase producing Salmonella enterica subsp. enterica serotype Infantis in a neonatal unit in Brazil. METHODS: A case-control study for risk factors for Salmonella Infantis systemic infection, environmental cultures, and evaluation of staffing and overcrowding and an assessment of infection control practices were performed. RESULTS: During July 1998 to June 1999, 140 Salmonella Infantis culture-positive patients were identified in the neonatal unit. Presence of a peripheral intravascular catheter was identified as an independent risk factor (odds ratio = 4.98; 95% CI = 1.59-19.31; P =.01) and each 250-g increase in birth weight as a protective factor (odds ratio = 0.76; 95% CI = 0.57-0.95; P =.03). Hospital stay was significantly longer and costs higher in case patients than in control patients. Salmonella Infantis was isolated from multiple environmental sources. Neonatal unit personnel were observed to make several breaks in infection control practices. The unit was understaffed and overcrowded. Prompt case identification, cohorting of patients, enhanced staff hand hygiene, and environmental cleaning terminated the outbreak. CONCLUSIONS: Inadequate infection control practices, nursery overcrowding, and understaffing can have an adverse effect on patient morbidity, mortality rates, and hospital cost.