Serotype 19F Research Articles

Capsule Contributes to Transmigration of Streptococcus pneumoniae Serotype 7F Meningitis Isolates through Complex Blood Brain Barrier Models

Streptococcus pneumoniae is known as an opportunistic pathogen which belongs to the most common etiological agents of local and systemic diseases in humans. In immune compromised patients, pneumococci infiltrate the meninges and cause life threatening inflammation. Recently, we have established a transwell-based Blood Brain Barrier (BBB) model with human endothelial-like cells and astrocytes providing a reliable tool to study pathogenesis mechanisms of bacterial and parasitical transmigration of the cellular barrier between vascular system and cerebral tissue. We applied this model with the aim to study the role of the polysaccharide capsule of a clinical isolate from a meningitis patient identified as a highly virulent serotype 7F pneumococcus. After optimization of the transformation procedure for this clinical isolate, we successfully deleted the capsule gene locus and confirmed loss of capsule expression by southern blot hybridization and electron microscopic visualization. In consistence with the already described inhibiting effect of capsular polysaccharides on phagocytosis by macrophages, the serotype 7F strain was more efficiently endocytosed by human monocytes (U937) as the corresponding capsule deficient mutant. Infection analyses using the BBB model with the serotype 7F wild type isolate and the mutant strain demonstrated a significantly reduced transmigration activity of the capsule-deficient serotype 7F. These results were further confirmed by infection of a second blood brain barrier model using Human Brain Microvascular Endothelial Cells (HBMEC). Interestingly, a collection of serotype 7F strains isolated from cerebral liquor or blood of children suffering from meningitis revealed a higher transmigration capacity as monitored in comparable infection studies with serotype 7F isolate derived from a non-invasive colonization. These data shed new light on the role of pneumococcal capsule in invasive infection process of the cerebral tissues and underline the requirement of adequate infection models to elucidate the diversity of highly virulent clinical isolates.

Overwhelming Pneumococcal Sepsis in a Patient with Splenic Hypoplasia

Department of Infectious Diseases, Yokohama Municipal Citizen’s HospitalA 58-year-old female was admitted due to severe sepsis and multi-organ failure with a fulminant purpuric rash.Meropenem, vancomycin and levofloxacin were administered, although no focus of infection was detected. However,computed tomography revealed a profoundly hypoplastic spleen, and a blood smear detected Howell-Jolly bodies.Blood cultures grew Streptococcus pneumoniae (serotype 22F) three hours after admission. The patient was finallydiagnosed as overwhelming pneumococcal sepsis with hyposplenism precipitated by splenic hypoplasia. Cliniciansshould pay attention to the splenic size and Howell-Jolly bodies in cases of sepsis of unknown origin.Keywords: Streptococcus pneumoniae, splenic hypoplasia, Howell-Jolly bodies, purpura fulminans, Pneumovaxµ 23,23-valent pneumococcal polysaccharide vaccineCASE REPORTA 58-year-old female was admitted to YokohamaMunicipal Citizen’s Hospital due to severe sepsis, andmulti-organ failure in April 2013. She developedgeneral fatigue, diarrhea and a high-grade fever of42°C on the day before hospitalization. On the day ofadmission, the patient also developed dyspnea. She hada past surgical history of osteosarcoma at the age of 23years and breast cancer at the age of 49 years requiringa mastectomy and axillary lymphadenectomy, followedby adjuvant chemotherapy and hormone therapy forfive years. She had not been previously vaccinated withthe 23-valent pneumococcal polysaccharide vaccine(PPSV23).In the emergency room, her vital signs were asfollows: blood pressure was 99/73mmHg, heart ratewas 100 beats/min, respiratory rate was 45 breaths/min, body temperature was 33.3°C and Glasgow ComaScale was E3V4M6 (total 13/15).Physical examination revealed purpura on her faceand extremities (Figure 1), whereas other systemexaminations were unrevealing. Despite a whole bodycomputed tomography (CT) scan, urine Gram staining,and rapid diagnostic testing (group A streptococcus,Streptococcus pneumoniae, and Influenza) from thepatient’s throat, it was not possible to detect theAuthor for correspondence: Kenichiro YaitaDepartment of Infectious Diseases, Yokohama Municipal Citizen’s Hospital, 56 Okazawa-cho, Hodogaya-ku,Yokohama, Kanagawa 240-8555, JapanE-mail: kyaita81@gmail.comReceived for publication 26 September 2013 and accepted in revised form 29 January 2014© 2014 The Japan Primary Care AssociationGeneral Medicine 2014, vol. 15, no. 1, p. 68–71.

Exposure of a 23F serotype strain of Streptococcus pneumoniae to cigarette smoke condensate is associated with selective upregulation of genes encoding the two-component regulatory system 11 (TCS11).

Alterations in whole genome expression profiles following exposure of the pneumococcus (strain 172, serotype 23F) to cigarette smoke condensate (160 μg/mL) for 15 and 60 min have been determined using the TIGR4 DNA microarray chip. Exposure to CSC resulted in the significant (P < 0.014–0.0006) upregulation of the genes encoding the two-component regulatory system 11 (TCS11), consisting of the sensor kinase, hk11, and its cognate response regulator, rr11, in the setting of increased biofilm formation. These effects of cigarette smoke on the pneumococcus may contribute to colonization of the airways by this microbial pathogen.

Genetic analysis of multidrug-resistant Streptococcus pneumoniae including meropenem resistance that was isolated from elderly residents with pneumonia in nursing-care facilities

From February to December 20XX, penicillin-resistant Streptococcus pneumoniae (PRSP) showing MICs of 16-32 microg/mL to cefotaxime (CTX) and 4-8 microg/mL to meropenem (MEPM) were isolated from 6 patients hospitalized at the general hospital S (2 cases) and hospital A (4 cases), close to the hospital S. Five elderly patients among these six cases came from nursing care facilities or nursing care-related medical facilities. All elderly persons (mean age: 81.7 years) were diagnosed as having pneumonia at the time of admission and the problematic PRSP was isolated from sputum samples collected on admission. Notably, all of these PRSP isolates simultaneously showed high resistance to macrolide agents mediated by an erm (B) gene and to fluoroquinolone agents via mutations in the gyrA and parC genes. Eventually, they were identified as multidrug-resistant S. pneumoniae (MDRSP) with high resistance to many agents. The capsule type of all strains was serotype 19F and multilocus sequence typing (MLST) revealed that they belonged to clonal complex (CC) 7993, which has not been reported before. It was thus concluded that the MDRSP that had spread within the nursing facilities was transmitted to the general hospitals via the elderly inpatients with pneumonia caused by these agents. Although one case finally had a poor outcome, the pneumococcal infection was not the direct trigger of the event. The current ratio of MDRSP is concluded to be very low. However, general hospitals that accept patients for therapeutic purposes from nursing-care facilities have to share epidemiological information in a timely manner with the nursing homes to prevent nosocomial infections.

Serologic Investigation of Pneumococcal Immunization of Autologous Hematopoietic Stem Cell Recipients

Our goal was to prospectively assess the immunological response to the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in autologous cell transplantation (AHCT) recipients using pneumococcal IgG (PNEIGG) titers. PNEIGG titers were collected prior to transplant (titer 1), 3-7 days following AHCT (titer 2), 1 year later at the time of vaccination (titer 3), and at 4-6 wks after vaccination (titer 4) for each of the 23 serotypes included in PPSV23. Seroreactivity was defined as a =4-fold increase in titer or a titer of >1.3 µg/mL following vaccination. Only 2 of 10 AHCT recipients with data through titer 4 were seroreactive in the majority of the 23 pneumococcal serotypes following PPSV23 which were not prior to vaccination. Median titer concentration increase reached the threshold for seroreactivity only for serotypes 12F and 15B. Antibody response of the 5 serotypes analyzed (4,8,12F,14,19F) was significantly lower in the AHCT population compared to healthy historical controls. There appears to be minimal immunogenicity as measured by PNEIGG titers to PPSV23 one year following AHCT.

L-Rhamnose Is Often an Important Part of Immunodominant Epitope for Pneumococcal Serotype 23F Polysaccharide Antibodies in Human Sera Immunized with PPV23

Streptococcus pneumoniae is a major human pathogen which expresses more than 90 serologically distinct capsular polysaccharides (PS) on the surface. Since pneumococcal PSs elicit protective antibodies against pneumococcal diseases, it is important to identify the immunological epitope eliciting anti-pneumococcal PS antibodies. L-rhamnose is a part of the 23F PS repeating unit and is known to be a critical part of immunodominant epitope which elicits antibodies against pneumococcal serotype 23F PS. In order to determine if L-rhamnose is a part of epitope recognized by functional antibodies specific for serotype 23F PS in human serum samples, we evaluated the opsonophagocytic killing of serotype 23F pneumococci by serum antibodies specific for L-rhamnose. Using 10 mM L-rhamnose, opsonic capacities (opsonic indices) of serum antibodies were inhibited by 60% in 19 sera (36%) and 30–60% in 16 sera (30%) out of 53 sera from young and old adults immunized with 23-valent pneumococcal polysaccharide vaccine (PPV23). Interestingly, when IgM antibodies were depleted from immune sera in order to preferentially study IgG antibodies, the proportion of young adult sera showing more than 60% inhibition in opsonic capacity by 10 mM of L-rhamnose increased from 33% (11/31) to 68% (21/31). On the other hand, IgM depletion did not alter the proportion for old adult sera. Therefore, young and old adults may produce different antigen binding profiles of IgG antibodies against serotype 23F PS.

Measurement of Pneumococcal Polysaccharide Antibodies

Janssen et al in this journal published their paper “Measurement of pneumococcal polysaccharide vaccine responses for immunodeficiency diagnostics: combined IgG responses compared to serotype specific IgG responses”. It is important to note that the message of this study is the observation that measuring antibodies against a mixture of all 23 pneumococcal serotype polysaccharides by ELISA does not reliably identify patients with a deficient response to pneumococcal polysaccharides. This holds true for patients with CVID, Specific Antibody Deficiency (SAD) or any other immunodeficiency affecting antibody production. Therefore, this study confirms a finding that is well established and beyond question; the only way to properly assess the ability of producing IgG anti-pneumococcal antibodies is to measure antibodies to each serotype individually. This is particularly important in the diagnosis of SAD since this deficiency is defined as an abnormal response to pure pneumococcal polysacchrides, as in the 23-valent poneumococcal vaccine [1]. Now that most young patients are already vaccinated with a pneumococcal conjugate vaccine and may have developed antibodies to serotypes present in these vaccines, the global ELISA test would not be able to identify the lack of response to serotypes that are only in the 23-valent polysaccharide and not in the conjugate vaccines. The study by Janssen et al does lend further clarification about the value of the Luminex method for the diagnosis of SAD. The Luminex method is now used by most commercial laboratories in the USA because it offers significant logistic advantages over the well-standardized but more cumbersome WHO ELISA method. Luminex allows the simultaneous quantitation of multiple serotype-specific antibodies. Both the third generation WHO ELISA and Luminex based tests offered in the USA incorporate double absorption of samples with cell wall polysaccharide (CPS) and serotype 22F. The WHO ELISA test results have been shown to correlate closely with opsonophagocytosis (OPA) measurements [2, 3]. Although the Luminex method has been approved for the measurement of specific anti-pneumococcal serotype IgG antibodies, the correlation of this test with the standard ELISA test is poor and its use as s a diagnostic tool for SAD still needs further study. Recent studies designed to validate the Luminex assay for anti-pneumococcal IgG antibodies have shown different degrees of variability when compared to the ELISA method [4]. Results obtained in a recent comprehensive com-

Genotypic characterization of Streptococcus pneumoniae serotype 19F in Malaysia

Streptococcus pneumoniae is an epidemiologically important bacterial pathogen. Recently, we reported the antibiotic susceptibility patterns of a limited collection of pneumococcal isolates in Malaysia with a high prevalence of erythromycin resistant strains. In the present study, 55 of the pneumococcal isolates of serotype 19F were further analysed by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The generated genotypic patterns were then correlated with the antibiograms previously reported. Forty-seven different PFGE profiles (PTs) were obtained, showing that the isolates were genetically diverse. MLST identified 16 sequence types (STs) with ST-236 being predominant (58.2%), followed by ST-81 (10.3%). Among the ST-236 isolates, 22 were erythromycin resistant S. pneumoniae (ERSP) and 15 were trimethoprim/sulfamethoxazole (TMP/SMX) resistant, while among ST-81, four isolates were ERSP and two were TMP/SMX resistant. The high prevalence of erythromycin resistant serotype 19F isolates of ST-236 in this study has also been reported in other North and South East Asian countries.

Phenotypic and Genotypic Characteristic of Invasive Pneumococcal Isolates from Both Children and Adult Patients from a Multicenter Surveillance in China 2005–2011

Streptococcus pneumoniae is an important pathogen in both children and the elderly, but previous studies in China have provided limited information about invasive pneumococcal disease (IPD). A total of 240 IPD S. pneumoniae strains (from 105 children and 135 adults) were collected from 12 cities in China in 2005–2011. Their phenotypes and genetic characteristics were analyzed. Streptococcus pneumoniae remained highly resistant to macrolides, tetracycline, and cotrimoxazole each year. Serotypes were assigned to the 240 isolates, and 19A (22.1%), 19F (21.7%), 14 (7.5%), 3 (7.1%), and 23F (5.4%) were the most prevalent, accounting for 63.8% of all strains. Serogroup 19 strains were significantly more common among children than among adults (58.7% vs 32.4%, respectively; P < 0.001). Serotypes 19F and 19A demonstrated higher resistance to β-lactams and cephalosporins than the other serotypes. The coverage of PCV13 was superior to that calculated for PCV7 and PCV10 (77.9% vs 40.8% and 47.1%, respectively), and coverage was higher in children than in adults (85.6% vs 72.1%, respectively; P = 0.012). A multilocus sequence typing analysis revealed great diversity, with nine clonal complexes and 83 singletons among all the strains. Specifically, CC271 was more common in children, whereas singletons were more prevalent in adults. Among the serogroup 19 strains, 84.7% were ST271, ST320, or ST236, belonging to CC271. The homogeneous genetic background of 19F and 19A, together with the high resistance of these strains, suggests that clonal spread is responsible for the high prevalence of serogroup 19 in IPD. This is the first large study to investigate IPD strains in both children and adults in China.

Streptococcus pneumoniae from Palestinian Nasopharyngeal Carriers: Serotype Distribution and Antimicrobial Resistance

Infections of Streptococcus pneumoniae in children can be prevented by vaccination; left untreated, they cause high morbidity and fatalities. This study aimed at determining the nasopharyngeal carrier rates, serotype distribution and antimicrobial resistance patterns of S. pneumoniae in healthy Palestinian children under age two prior to the full introduction of the pneumococcal 7-valent conjugate vaccine (PCV7), which was originally introduced into Palestine in a pilot trial in September, 2010. In a cross sectional study, nasopharyngeal specimens were collected from 397 healthy children from different Palestinian districts between the beginning of November 2012 to the end of January 2013. Samples were inoculated into blood agar and suspected colonies were examined by amplifying the pneumococcal-specific autolysin gene using a real-time PCR. Serotypes were identified by a PCR that incorporated different sets of specific primers. Antimicrobial susceptibility was measured by disk diffusion and MIC methods. The resulting carrier rate of Streptococcus pneumoniae was 55.7% (221/397). The main serotypes were PCV7 serotypes 19F (12.2%), 23F (9.0%), 6B (8.6%) and 14 (4%) and PCV13 serotypes 6A (13.6%) and 19A (4.1%). Notably, serotype 6A, not included in the pilot trial (PCV7) vaccine, was the most prevalent. Resistance to more than two drugs was observed for bacteria from 34.1% of the children (72/211) while 22.3% (47/211) carried bacteria were susceptible to all tested antibiotics. All the isolates were sensitive to cefotaxime and vancomycin.Any or all of these might impinge on the type and efficacy of the pneumococcal conjugate vaccines and antibiotics to be used for prevention and treatment of pneumococcal disease in the country.

Dynamics of the pneumococcal population causing acute exacerbations in COPD patients in a Barcelona hospital (2009-12): comparison with 2001-04 and 2005-08 periods

Pneumococci are an important cause of acute exacerbations in patients with chronic obstructive pulmonary disease (COPD). In the last decade, the pneumococcal population has changed, mainly due to the introduction of the 7-valent conjugate vaccine (PCV7). We analysed the antimicrobial susceptibility (microdilution), serotype (PCR) and genotype (PFGE/multilocus sequence typing) of pneumococci causing acute exacerbations during the period 2009-12. Results were compared with two previously published historic periods (2001-04 and 2005-08). A total of 206 pneumococci were collected from 162 COPD patients with acute exacerbations. Compared with previous periods, no significant changes in the rate of multidrug resistance were observed (36.2% in the 2001-04 period to 33.5% in the 2009-12 period, P = 0.644). The most frequent serotypes in the 2009-12 period were 15A (9.6%), 3 (8.1%), 19F (6.6%), 11A (6.1%) and 6C (5.6%), which accounted for 36.0%. A drastic decrease in PCV7 serotypes was observed throughout the study period (from 39.7% in 2001-04 to 10.9% in 2009-12, P < 0.001); non-PCV13 serotypes increased from 44.9% to 71.2%, especially 15A (from 2.2% to 9.6%) and 6C (from 0.0% to 5.6%) (P < 0.05). The most frequent genotypes (clonal complexes, CCs) in the 2009-12 period were CC63(15A,19F,15F) (9.1%), CC180(3) (4.5%), CC62(11A) (4.0%), CC97(10A) (4.0%), CC386(6C) (3.5%), CC260(3) (3.5%) and CC30(16F) (3.5%). Serotypes 19F, 19A, 6A and 6C were genetically diverse. PCV7 serotypes have decreased dramatically. In parallel, two non-PCV7 serotypes (15A and 6C) and their related genotypes (CC63 and CC386) showed a significant increase. Although resistance rates to β-lactams decreased over time, multidrug resistance remained stable.

MOLECULAR TYPING OF STREPTOCOCCUS PNEUMONIAE BY THE MULTIPLEX POLYMERASE CHAIN REACTION ASSAY IN ACCORDANCE TO THE PREVALENCE OF SEROTYPES IN THE RUSSIAN FEDERATION

Aim : to compare two methods of S. pneumoniae molecular typing: classic serological method and the multiplex polymerase chain reaction (M-PCR) assay modified in accordance to the date on the serotypes circulating in Russian Federation. Patients and methods : 420 pneumococcal isolates mainly from non-sterile loci were analyzed. After microbiological identification pneumococci were serologically typed with the means of specific antiserum produced by Staten Serum Institute (Denmark) in latex agglutination test and/or capsular swelling method. At the same time we performed series of the M-PCR, which consisted of 7 consecutive reactions at the most. Results : serotype was identified by the means of serological method in all 420 strains of S. pneumoniae; in total we determined 24 different serotypes. By the means of the M-PCR we succeeded in identification of 95% (399/420) examined strains, and 90% of them were typed during the first 3 reactions. All isolates failed to be typed by M-PCR (n =21) have serotypes not included into the composition of the M-PCR. The results of serological and molecular typing were identical in 99,2% (396/399) of the isolates; 3 strains showed contradictory results: serotype 19A was found on serological assay and serotype 19F — on PCR assay. Conclusions : the introduced modification of M-PCR allows correct identification of pneumococcal serotype more than in 90% of strains circulating in the Russian Federation, including all serotypes of pneumococcal polysaccharide conjugate vaccine.

Epidemiology of penicillin-non-susceptible pneumococci in Iceland, 1995-2010

The first penicillin-non-susceptible pneumococci (PNSP) were identified in Iceland in 1988. A rapid increase followed, associated with expansion of a single multiresistant clone, Spain(6B)-2, peaking at 19.8% in 1993. After interventions led to reduced antimicrobial use in children, the prevalence of PNSP decreased until 1995. The aim of this study was to follow the evolution of PNSP from 1995 to 2010, the period preceding the introduction of conjugated pneumococcal vaccines into the vaccination programme. The laboratory at the Landspitali University Hospital serves ∼ 85% of the Icelandic population. All pneumococci isolated from 1995 to 2010 (n = 13,937) were stored (-80 °C). Oxacillin-resistant isolates were serotyped and penicillin MICs were determined. Selected strains were genotyped by PFGE and multilocus sequence typing. In 1995, the rate of PNSP was 24.2%, declining to 13.6% in 2001, and then increasing to 38.6% in 2010. Similar changes were observed for resistance to erythromycin and tetracycline. In 1995, 60.7% of PNSP were serotype 6B, mainly the Spain(6B)-2 clone, declining to 5.7% in 2010. PNSP of serotype 19F rapidly increased after 2004 to comprise 85.8% of all serogrouped PNSP in 2010, with most isolates belonging to a single multiresistant PFGE clone identified as sequence type (ST) 271 and ST1968, representing single- and double-locus variants of the international clone Taiwan(19F)-14, respectively. PNSP were most common among young children, from the nasopharynx, middle ear and lower respiratory tract. The epidemiology of PNSP was dominated by two multiresistant clones. The second expanded rapidly when the first one was disappearing, causing higher antibiotic resistance rates among pneumococci than seen before in Iceland.

Safety and immunogenicity of 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in Nigerian children

In a previous study, 3-dose primary vaccination of Nigerian infants with the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) was immunogenic for vaccine pneumococcal serotypes, with comparable tolerability between PHiD-CV and control groups. In an open-label study (ClinicalTrials.gov, NCT01153893), 68 primed children received a PHiD-CV booster dose co-administered with a diphtheria-tetanus-acellular pertussis (DTPa) booster dose at 15–21 months and 36 children unprimed for pneumococcal vaccination received two PHiD-CV catch-up doses (first dose co-administered with DTPa booster dose) at 15–21 and 17–23 months. Adverse events were recorded and immune responses were measured before and one month after vaccination. In both groups, pain was the most frequent solicited local symptom and fever was the most frequent solicited general symptom after the booster dose and each catch-up dose. Few grade 3 solicited symptoms and no vaccine-related serious adverse events were reported. After booster vaccination, for each vaccine serotype, at least 98.5% of children had an antibody concentration ≥0.2 µg/ml and at least 94.0% had an opsonophagocytic activity (OPA) titer ≥8. After 2-dose catch-up, for each vaccine serotype, at least 97.1% had an antibody concentration ≥0.2 µg/ml, except for serotypes 6B (82.9%) and 23F (88.6%), and at least 91.4% had an OPA titer ≥8, except for serotypes 6B (77.4%) and 19F (85.3%). PHiD-CV induced antibody responses against protein D in both groups. In conclusion, PHiD-CV administered to Nigerian toddlers as a booster dose or 2-dose catch-up was well tolerated and immunogenic for vaccine pneumococcal serotypes and protein D.

High nasopharyngeal carriage of non-vaccine serotypes in Western Australian aboriginal people following 10 years of pneumococcal conjugate vaccination.

BackgroundInvasive pneumococcal disease (IPD) continues to occur at high rates among Australian Aboriginal people. The seven-valent pneumococcal conjugate vaccine (7vPCV) was given in a 2-4-6-month schedule from 2001, with a 23-valent pneumococcal polysaccharide vaccine (23vPPV) booster at 18 months, and replaced with 13vPCV in July 2011. Since carriage surveillance can supplement IPD surveillance, we have monitored pneumococcal carriage in western Australia (WA) since 2008 to assess the impact of the 10-year 7vPCV program. MethodsWe collected 1,500 nasopharyngeal specimens from Aboriginal people living in varied regions of WA from August 2008 until June 2011. Specimens were cultured on selective media. Pneumococcal isolates were serotyped by the quellung reaction. Results Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis were carried by 71.9%, 63.2% and 63.3% respectively of children <5 years of age, and 34.6%, 22.4% and 27.2% of people ≥5 years. Of 43 pneumococcal serotypes identified, the most common were 19A, 16F and 6C in children <5 years, and 15B, 34 and 22F in older people. 7vPCV serotypes accounted for 14.5% of all serotypeable isolates, 13vPCV for 32.4% and 23vPPV for 49.9%, with little variation across all age groups. Serotypes 1 and 12F were rarely identified, despite causing recent IPD outbreaks in WA. Complete penicillin resistance (MIC ≥2µg/ml) was found in 1.6% of serotype 19A (5.2%), 19F (4.9%) and 16F (3.2%) isolates and reduced penicillin susceptibility (MIC ≥0.125µg/ml) in 24.9% of isolates, particularly 19F (92.7%), 19A (41.3%), 16F (29.0%). Multi-resistance to cotrimoxazole, tetracycline and erythromycin was found in 83.0% of 23F isolates. Among non-serotypeable isolates 76.0% had reduced susceptibility and 4.0% showed complete resistance to penicillin.ConclusionsTen years after introduction of 7vPCV for Aboriginal Australian children, 7vPCV serotypes account for a small proportion of carried pneumococci. A large proportion of circulating serotypes are not covered by any currently licensed vaccine.

Serum antibody responses to pneumococcal colonization in the first 2 years of life: results from an SE Asian longitudinal cohort study

AbstractAssessment of antibody responses to pneumococcal colonization in early childhood may aid our understanding of protection and inform vaccine antigen selection. Serum samples were collected from mother-infant pairs during a longitudinal pneumococcal colonization study in Burmese refugees. Maternal and cord sera were collected at birth and infants were bled monthly (1–24 months of age). Nasopharyngeal swabs were taken monthly to detect colonization. Serum IgG titres to 27 pneumococcal protein antigens were measured in 2624 sera and IgG to dominant serotypes (6B, 14, 19F, 19A and 23F) were quantified in 864 infant sera. Antibodies to all protein antigens were detectable in maternal sera. Titres to four proteins (LytB, PcpA, PhtD and PhtE) were significantly higher in mothers colonized by pneumococci at delivery. Maternally-derived antibodies to PiuA and Spr0096 were associated with delayed pneumococcal acquisition in infants in univariate, but not multivariate models. Controlling for infant age and previous homologous serotype exposure, nasopharyngeal acquisition of serotypes 19A, 23F, 14 or 19F was associated significantly with a ≥2-fold antibody response to the homologous capsule (OR 12.84, 7.52, 6.52, 5.33; p <0.05). Acquisition of pneumococcal serotypes in the nasopharynx of infants was not significantly associated with a ≥2-fold rise in antibodies to any of the protein antigens studied. In conclusion, nasopharyngeal colonization in young children resulted in demonstrable serum IgG responses to pneumococcal capsules and surface/virulence proteins. However, the relationship between serum IgG and the prevention of, or response to, pneumococcal nasopharyngeal colonization remains complex. Mechanisms other than serum IgG are likely to have a role but are currently poorly understood.

Population Genetic Structure of Streptococcus pneumoniae in Kilifi, Kenya, Prior to the Introduction of Pneumococcal Conjugate Vaccine

BackgroundThe 10-valent pneumococcal conjugate vaccine (PCV10) was introduced in Kenya in 2011. Introduction of any PCV will perturb the existing pneumococcal population structure, thus the aim was to genotype pneumococci collected in Kilifi before PCV10. Methods and FindingsUsing multilocus sequence typing (MLST), we genotyped >1100 invasive and carriage pneumococci from children, the largest collection genotyped from a single resource-poor country and reported to date. Serotype 1 was the most common serotype causing invasive disease and was rarely detected in carriage; all serotype 1 isolates were members of clonal complex (CC) 217. There were temporal fluctuations in the major circulating sequence types (STs); and although 1-3 major serotype 1, 14 or 23F STs co-circulated annually, the two major serotype 5 STs mainly circulated independently. Major STs/CCs also included isolates of serotypes 3, 12F, 18C and 19A and each shared ≤2 MLST alleles with STs that circulate widely elsewhere. Major CCs associated with non-PCV10 serotypes were predominantly represented by carriage isolates, although serotype 19A and 12F CCs were largely invasive and a serotype 10A CC was equally represented by invasive and carriage isolates. ConclusionsUnderstanding the pre-PCV10 population genetic structure in Kilifi will allow for the detection of changes in prevalence of the circulating genotypes and evidence for capsular switching post-vaccine implementation.

Antimicrobial Resistance in Relation to Sero- and Genotypes Among InvasiveStreptococcus pneumoniaein Finland, 2007–2011

We studied the serotypes and antimicrobial resistance of the invasive Streptococcus pneumoniae that had been isolated in Finland during 5 years. The 10-valent vaccine was introduced into the National Vaccination Programme in September 2010. We examined the antimicrobial resistance and serotype distribution of the invasive pneumococci (n=4,194) that had been isolated in Finland during 2007-2011. The penicillin-resistant (PEN R) (≥4 mg/L) isolates (n=12) were genotyped by MLST. Serotype 14 was consistently the most prominent serotype, covering 18.0-20.1% of all the isolates. The proportion of serotypes 3, 19A, and 22F increased significantly, while that of 6B and the PCV10 vaccine serotypes combined decreased. PEN nonsusceptibility (≥0.12 mg/L) increased, ranging from 14.4% to 23.2% by year, and was the highest (28.5%) among the 0-2 year olds. The PEN and/or erythromycin (ERY) nonsusceptibility of several vaccine serotypes (4, 6B, 14, and 19F) increased significantly over the study period. The ERY nonsusceptibility was 26.6%. There was limited diversity among the PEN R isolates; all were a part of serotype 19F, 19A, or 14, and two globally disseminated genetic lineages carrying one or both pilus-encoding islets. High and/or increasing nonsusceptibility rates underline the importance of monitoring the serotype distribution and antimicrobial susceptibility of pneumococci, especially after large-scale vaccination.

Early-onset Streptococcus pneumoniae Neonatal Sepsis and Meningitis in the 13-valent Vaccine Era

To the Editors: Streptococcus pneumoniae is a rare cause of invasive infections in neonates, and in the United States and Europe accounts for 1% to 5.5% of neonatal sepsis cases, being more prevalent in developing countries (11.5%).1,2 Most infections occur during the second or third week of life, with a high case fatality rate (50%).1 To know the serotypes involved in neonatal infections in the era of pneumococcal conjugate 13-valent vaccine (PCV13) would be of interest. We report a case of early-onset pneumococcal sepsis and meningitis by serotype 7F, a serotype included in PCV13. CASE REPORT A 1-day-old male neonate presented with fever, grunting, tachypnea and septic appearance. He was vaginally born at term, weighed 2635 g and the Apgar score was 8/9. There was no history of maternal fever, chorioamnionitis and prolonged rupture of membranes or colonization with Streptococcus agalactiae. The chest radiograph was normal. Laboratory investigation revealed pancytopenia, coagulopathy and increased C-reactive protein. Cerebrospinal fluid analysis showed 160 leukocytes (85% polymorphonuclear cells), protein 5.6 g/L and glucose 5 mg/dL; Gram-positive cocci were observed on the Gram-stained smear. Cultures of blood and cerebrospinal fluid were positive for S. pneumoniae. The mother was asymptomatic, but a vaginal culture showed a pure growth of S. pneumoniae. All isolates belonged to serotype 7F and shared identical pattern of pulse field gel electrophoresis, being susceptible to ampicillin and cefotaxime. Treatment with ampicillin plus cefotaxime was administered, but the patient developed septic shock and massive brain hemorrhage that caused his death. COMMENT Early-onset invasive disease caused by S. pneumoniae occurs during the first 72 hours of life and causes sepsis, meningitis and pneumonia. It is less frequent than late onset infections and has a worse prognosis, especially when it starts before 48 hours of life or is secondary to an invasive maternal infection.3 In early-onset disease, pneumococci may reach the fetus via the transplacental route, secondary to maternal bacteremia, ascending from the maternal genital tract or passage through the birth canal. Pneumococcus is not present in the normal vaginal flora, and several studies have demonstrated that genital colonization by this microorganism is uncommon (<0.03%).2,4 Our patient’s mother was asymptomatic, but her vagina was heavily colonized by pneumococci. In this case, the newborn most likely acquired the infection vertically while passing through the colonized birth canal and showed clinical features similar to those of S. agalactiae early-onset infections. The serotype of the isolates, maternal and newborn, was 7F, one of the new serotypes included in PCV13. In Spain, serotype 7F along with 1 and 19A were the most prevalent in invasive infections in 2010, when PCV13 was released.5 However, PCV13 coverage in our children is only 56% because it is not included in the national immunization program, and consequently there is no herd immunity. Although vaccination of childbearing age women with PCV13 would not be cost effective, it could be useful until PCV13 achieves greater coverage in our population.6 Julio F. Fothy, MD Susanne Vetter, MD Antonio Iñigo, MD José Gil, MD José L.Pérez, PhD Juan A. Hervás, MD, PhD Departments of Microbiology and Pediatrics Son Espases University Hospital University Institute of Health Sciences-IUNICS University of The Balearic Islands Palma de Mallorca, Spain

Kronik Akciğer Hastalığı Olan, Akut Alevlenme ve Pnömoni Tanısı ile Başvuran Çocuklarda Streptococcus pneumoniae Serotip Dağılımı ve Antimikrobiyal Duyarlılıkları

This study aimed to investigate serotype distribution and antimicrobial resistance of Streptococcus pneumoniae isolates obtained from children with chronic respiratory diseases admitted to hospital with a diagnosis of acute exacerbations between 2008-2010 at Marmara University Hospital, Istanbul, Turkey. Sixty one S.pneumoniae strains isolated from the respiratory samples of patients were studied for erythromycin, clindamycin, tetracyline, trimethoprim-sulphametoxazole (TMP-SMX), vancomycin, levofloxacin susceptibilities by disk diffusion method; MIC values of penicillin and ceftriaxone were determined by E-test (AB Biodisk, Sweden). Results were evaluated according to the CLSI standards. The erythromycin-clindamycin double disc method was applied for the detection of macrolide resistance phenotypes. The presence of macrolide resistance genes, ermB, mef(A)/(E), ermTR were determined by PCR using specific primers for each gene. The serotypes were determined by multiplex PCR using specific primers for 40 different serotypes. According to CLSI criteria, penicillin resistance in S.pneumoniae isolates were found to be 8.2% (5/61) and intermediate resistance rate was 54% (33/61) for oral penicillin. Penicillin resistance were found to be only 1.6% (1/61) for parenteral penicillin. Resistance rates of erythromycin, clindamycin, tetracyline, TMP-SMX were detected as 55.8%, 46%, 47.5% and 67.2%; respectively. No resistance was detected to vancomycin and levofloxacin. Constitutive macrolide-lincosamide-streptogramin B (cMLSB) phenotype and M phenotype were observed in 82.4% (n= 28) and 17.6% (n= 6) of the macrolide resistant isolates, respectively. Inducible macrolide-lincosamide-streptogramin B (iMLSB) phenotype was not detected. The macrolid resistance genotypes, ermB, mef(A)/(E), were positive 50% and 14.7%; respectively. Both ermB and mef(A)/(E) genes were detected 35.3% of the macrolid resistant isolates. None of the isolates were positive for ermTR gene. The most common S.pneumoniae serotypes were determined as serotype 19F, 23F and 6, furthermore penicillin (34%, 15.7% and 18.4%, respectively) and macrolide (38.2%, 20.6% and 14.7%, respectively) resistance rates of those serotypes were found relatively high. Serotype covarage of 7-, 10-, 13-valent conjugated pneumococcal vaccines and 23-valent pneumococcal vaccine were 65%, 67%, 69%, and 78.6%, respectively. In our country, use of the vaccines with these coverage rates has been observed to be effective in children exposed to intensive use of antibiotics with chronic lung disease.