Biomedical subjects

Noboru Yamanaka

Publications and source records attributed to Noboru Yamanaka.

At least 19 recordsLinked to original sources

PubMed2006

Rapid identification of nontypeable and serotype b Haemophilus influenzae from nasopharyngeal secretions by the multiplex PCR.

OBJECTIVE: Heamophilus influenzae (H. influenzae) is an important pathogen responsible for both invasive and non-invasive infectious diseases. While encapsulated type b strain recognized as a major cause of severe invasive diseases, nontypeable strains are the major causes of non-invasive infectious diseases. Detection of this pathogen from nasopharyngeal secretions (NPS) is important. METHODS: We developed a multiplex polymerase chain reaction (PCR) for rapid identification of nontypeable and serotype b H. influenzae from nasopharyngeal secretions. RESULTS: A total 25 nasopharyngeal secretions were evaluated in this study. The multiplex PCR provided rapid and unequivocal results for determining either nontypeable or encapsulated typeable especially type b strains including a determination of beta-lactamase productions. CONCLUSION: The multiplex PCR based serotyping provided more reliable results than slide agglutination test (SAT) and is a valuable and expeditious method for identification of H. influenzae with determining capsular serotypes.

Haemophilus influenzae↗

PubMed2006

Study of nasopharyngeal bacterial flora. Second report. Variations in nasopharyngeal bacterial flora in children aged 6 years or younger when administered antimicrobial agents. Part 1.

In our first report, we investigated nasopharyngeal bacterial flora related to penicillin-resistant Streptococcus pneumoniae (PRSP) and beta-lactamase-negative ampicillin-resistant Haemophilus influenzae (BLNAR) and their relation to acute upper respiratory tract infection (AURTI). This report analyzes the results of a study of nasopharyngeal bacterial flora before the administration of antimicrobial agents in 172 AURTI patients aged 6 years or younger. In addition to Gram staining, microscopic observation, and culturing, a polymerase chain reaction (PCR) method was used to identify PRSP (gPRSP) and BLNAR (gBLNAR) drug-resistant genes. Of the patients analyzed, 90% had acute otitis media (AOM) and were aged 2 years or younger. The antimicrobial agents administered were amoxicillin (34%), clavulanic acid/amoxicillin (11%), cefditren pivoxil (CDTR-PI) (43%), and others (12%). This was particularly true for patients administered CDTR-PI, among whom there were many who had already suffered one or more episodes of AOM by the age of 1 year or younger, and many in which gPRSP were detected (P < 0.01). There was a significant relation between the degree of nasopharyngeal inflammation indicated by leukocyte infiltration images and the amount of S. pneumoniae and H. influenzae detected, which are the main pathogenic bacteria causing AOM (P < 0.01). In addition to leukocyte infiltration images, there were cases in which shedding of ciliated cells was observed and/or giant monocytic cells. Both nasopharyngeal leukocyte infiltration images and/or shed cell findings observed in infant AURTI cases are important indices for the prompt detection of gPRSP and/or gBLNAR and appropriate doses of antimicrobial agents.

Age Factors↗

PubMed2006

Study of nasopharyngeal bacterial flora. Second report. Variations in nasopharyngeal bacterial flora in children aged 6 years or younger when administered antimicrobial agents. Part 2.

This report focuses on changes in the nasopharyngeal bacterial flora before and after administration of antimicrobial agents in 172 cases of acute upper respiratory infection in patients aged 6 years or younger. The antimicrobial agents administered were amoxicillin (AMPC) (34%), clavulanic acid/amoxicillin compound (11%), cefditren pivoxil (CDTR-PI) (43%), and others (12%). Changes in nasopharyngeal bacterial flora were investigated with reexaminations conducted after 2-5 days (day 2-5 subgroup), 6-10 days (day 6-10 subgroup), and 11 days and thereafter. There was a significant reduction in the Streptococcus pneumoniae detected in the group administered AMPC (AMPC group) in the day 2-5 subgroup and the day 6-10 subgroup. There was also a significant decrease in H. influenzae in the group administered CDTR-PI (CDTR-PI group) in the day 2-5 subgroup. From this it was inferred that for the most part significant changes in infectious nasopharyngeal bacteria occurred in the day 2-5 subgroups. However, a significant improvement in the degree of inflammation, as indicated by leukocyte infiltration images for the AMPC group, was observed in the day 2-5 subgroup, and for the CDTR-PI group in the day 6-10 subgroup. On the other hand, in both the antimicrobial agent groups, S. pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis were newly detected at reexamination. Furthermore, a difference in the incidence of these bacteria was observed between the 2 antimicrobial agent groups. It was suggested that such phenomena related to the survival of resistant strains or a recurrence otitis media.

Anti-Infective Agents↗

PubMed2006

In vitro induction and selection of fluoroquinolone-resistant mutants of Streptococcus pyogenes strains with multiple emm types.

OBJECTIVES: To perform a systematic analysis of point mutations in the quinolone resistance determining regions (QRDRs) of the DNA gyrase and topoisomerase genes of emm type 6 and other emm types of Streptococcus pyogenes strains after in vitro exposure to stepwise increasing concentrations of levofloxacin. METHODS: Twelve parent strains of S. pyogenes, each with a different emm type, were chosen for stepwise exposure to increasing levels of levofloxacin followed by selection of resistant mutants. The QRDRs of gyrA, gyrB, parC and parE correlating to mutants with increased MICs were analysed for point mutations. RESULTS: Multiple mutants with significantly increased MICs were generated from each strain. The amino acid substitutions identified were consistent regardless of emm type and were similar to the mechanisms of resistance reported in clinical isolates of S. pyogenes. The number of induction/selection cycles required for the emergence of key point mutations in gyrA and parC was variable among strains. For each parent-mutant set, when MIC increased, serine-81 of gyrA and serine-79 of parC were the primary targets for amino acid substitutions. No point mutations were found in the QRDRs of gyrB and parE in any of the resistant mutants sequenced. CONCLUSIONS: Despite its intrinsic polymorphism in the QRDR of parC, emm type 6 is not more likely to develop high-level resistance to fluoroquinolones when compared with other emm types. All emm types seem equally inducible to high-level fluoroquinolone resistance.

Anti-Infective Agents↗

PubMed2006

Efficacy of a novel oral carbapenem, tebipenem pivoxil (TBM-PI), against experimental otitis media caused by penicillin resistant Streptococcus pneumoniae in chinchilla.

An animal model of otitis media using chinchillas was developed to evaluate the efficacy of tebipenem pivoxil (TBM-PI) against experimental otitis media. Chinchillas inoculated via the transbullar approach with Streptococcus pneumoniae serogroup 6 were included in the efficacy study with TBM-PI, amoxicillin (AMX) or untreated as controls. TBM-PI resulted in survival rate of 83%, compared with 25% survival for AMX and 0% survival for controls (p<0.01). Quantitative cultures in the middle ear effusions at day 5 of the TBM-PI group yielded 3.5+/-2.4log(10)CFUs/ml. TBM-PI is a promising antibiotic for the treatment of acute otitis media.

Administration, Oral↗

PubMed2006

Maternal intranasal immunization with outer membrane protein P6 maintains specific antibody level of derived offspring.

Acute otitis media is one of the most common infectious diseases in children younger than 2 years of age. Immunological studies in young children have revealed that immature antibody-responses to major pathogens, such as S. pneumoniae, H.influenzae, would cause the vulnerability to upper respiratory tract infections. Thus, it is very important to induce effective protective immunity among children younger than 2 years of age. In this study, we evaluated the capacity of maternal immunization with P6 of H. influenzae to evoke specific antibody to P6 and to transfer it to offspring. We intranasally immunized mother mice with P6 and investigated the induction of specific antibody in sera and breast milk. The specific antibody among offspring delivered by immunized mother was also investigated according to the nursing status to evaluate the importance of breast feedings by immunized mothers. Anti-P6 specific IgG in sera were high at delivery and maintained during nursing periods among P6-immunized mother mice. Anti-P6 specific IgG were predominantly induced in breast milk. IgG subclass induced in sera and breast milk from P6-immunized mother mice were IgG2b, followed by IgG1 and IgG2a subclass. Offspring delivered by P6-immunized mothers had anti-P6 specific IgG in sera at the birth. The levels of anti-P6 specific IgG in sera from offspring breast-fed by P6-immunized mothers were then increased until day 14 and then decreased on day 21. The anti-P6 specific IgG in sera from offspring breast-fed by sham-immunized mothers were rapidly decreased after birth. The current findings strongly suggest that maternal intranasal immunization with P6 would be an attractive strategy against NTHi infections during early childhood. It can supply protective antibodies via transplacental transfer during pregnancy and via breast milk after birth.

Administration, Intranasal↗

PubMed2006

High prevalence of Streptococcus pneumoniae with mutations in pbp1a, pbp2x, and pbp2b genes of penicillin-binding proteins in the nasopharynx in children in Japan.

OBJECTIVE: To evaluate the resistances of Streptococcus pneumoniae to beta-lactams developed by stepwise alterations in high-molecular-weight penicillin-binding proteins (PBPs) with a reduced binding affinity of beta-lactams. Among the numerous mutations in pbp genes that alter the affinity for beta-lactams, the decreased affinity of PBP1A, 2X and 2B is especially important in the development of resistances to beta-lactams. STUDY DESIGN: Retrospective review. METHODS: In this study, we investigated the mutations in pbp1a, pbp2x, and pbp2b genes evaluated by polymerase chain reaction (PCR) in 866 pneumococcal isolates collected from the nasopharynx of Japanese children with acute otitis media. RESULTS: 210 strains (24.3%) exhibited no mutations in the three pbp genes. 333 strains (38.5%) had mutations in the three pbp genes, 78 (9.0%) in two pbp genes, whereas 245 (28.3%) displayed mutations in only one pbp gene. Among the 656 strains with mutations in pbp genes, 620 (94.5%) strains had mutations in pbp2x. The annual prevalence of antimicrobial-resistant S. pneumoniae showed a gradual increase in strains with mutations in the three pbp genes and a parallel decrease in strains without mutations. CONCLUSIONS: PCR-based genotyping can characterize the antimicrobial resistances in pneumococci along with minimal inhibitory concentrations (MICs). Physicians should pay attention to the recent increase in antimicrobial-resistant S. pneumoniae when treating pediatric acute otitis media.

Acute Disease↗

PubMed2006

Evaluation of serotypes of Streptococcus pneumoniae isolated from otitis media patients by multiplex polymerase chain reaction.

The increasing difficulty in the management of pneumococcal acute otitis media in parallel with increases in antimicrobial-resistant strains has led to much interest in pneumococcal capsular types for the adoption of effective prevention by vaccines. This study shows that multiplex polymerase chain reaction is a valuable and expeditious method for the capsular typing of pneumococci. The multiplex polymerase chain reaction method accurately detects the majority of serotypes and serogroups frequently isolated from pediatric patients with acute otitis media, allowing the characterization of the colonization patterns for further implications of pneumococcal vaccines.

Bacterial Capsules↗

PubMed2006

Study of upper respiratory tract bacterial flora: first report. Variations in upper respiratory tract bacterial flora in patients with acute upper respiratory tract infection and healthy subjects and variations by subject age.

With the appearance of penicillin-resistant Streptococcus pneumoniae, there has been increasing debate concerning antimicrobial treatments for acute upper respiratory tract infection (AURTI) and acute otitis media in children. This study compares the nasopharyngeal bacterial flora in patients with AURTI (AURTI group; 710 subjects) and healthy subjects (HS group; 380 subjects). The comparisons were made between subjects aged 6 years or younger (0-6 subgroup: 330 subjects), between 7 and 74 years (7-74 subgroup: 668 subjects), and 75 years and older (92 subjects), because the subjects were subgrouped as described above dependent on the maturity of the protective immunity. In the HS group 7-74 subgroup, viridans group streptococci, Staphylococcus aureus, coagulase-negative staphylococci, and Corynebacterium sp. with a detection rate of 10% or more were classified as normal nasal flora (NNF), and Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis were classified as drum cavity pathogens (DCP). In the 0-6 subgroup, although the detection rate for DCP bacteria in the AURTI group tended to be high, it did not reach a significant difference, whereas the detection rate for NNF bacteria was significantly lower. This trend was also observed to some degree in the other age subgroup. In the 0-6 subgroup, leukocyte infiltration observed with a microscope indicated the closest relationship between S. pneumoniae detection rate and detection quantity. These results suggest that in the 0-6 subgroup the tendency for patients with AURTI to have NNF bacteria as well as DCP bacteria should be taken into consideration.

Acute Disease↗

PubMed2006

Antimicrobial resistance in Haemophilus influenzae isolated from the nasopharynx among Japanese children with acute otitis media.

CONCLUSION: High prevalence of penicillin-binding protein (PBP) gene mutated (PGM) strains of H. influenzae should be taken into account when treating otitis media in children. OBJECTIVE: To evaluate prevalence of ss-lactamase nonproducing ampicillin-resistant (BLNAR) strains of Haemophilus influenzae with mutations in ftsI gene encoding penicillin-binding protein 3 (PBP3) among children with otitis media. METHODS: A total of 644 nasopharyngeal isolates of H. influenzae was collected from pediatric acute otitis media (AOM) patients with or without otitis media with effusions (OME) at the clinics of Otolaryngology-Head and Neck Surgery, Wakayama Medical University Hospital and six affiliated hospitals in Wakayama prefecture between January 1999 and December 2003. Minimal inhibitory concentrations (MICs) of ampicillin (AMP), cefditoren (CDN), cefdinir (CFD), cefaclor (CCL), cefpodoxime (CPD), and cefcapene (CFPN) were determined by the microbroth dilution method according to the recommendations of the National Committee for Clinical Laboratory Standards (NCCLS). Types of mutations in PBP3 gene (ftsI) were evaluated by a polymerase chain reaction (PCR)-based genotyping method. ss-Lactamase gene (bla) was also identified by PCR. RESULTS: ss-Lactamase-producing (BLP) strains with the bla gene were identified in 16 (2.5%) of isolates. PGM strains were identified in 279 (43.3%) isolates. There were 242 (37.6%) PGM1-nonBLP strains with mutations in variable mutated locus of ftsI, 35 (5.4%) PGM2-nonBLP strains with mutations in highly mutated locus of ftsI, 2 (0.3%) BLP-PGM strains with mutations in ftsI and producing ss-lactamase. BLP-nonPGM strains producing ss-lactamase without mutations in ftsI were identified in 14 (2.2%) isolates. MICs of PGM1-nonBLP strains to AMP were 0.5-2.0 microg/ml. The MIC(90) of CDN to the PGM1-nonBLP strains was lowest (0.06 microg/ml). Proportions of PGM1-nonBLP strains rapidly increased during 1999 to 2002 and then decreased in 2003. In contrast, PGM2-nonBLP strains increased in 2003.

Acute Disease↗

PubMed2006

Antimicrobial resistance of Haemophilus influenzae isolated from the nasopharynx of Japanese children with acute otitis media.

CONCLUSION: A high prevalence of penicillin-binding protein gene-mutated (PGM) strains of Haemophilus influenzae should be taken into account when treating otitis media in children. OBJECTIVE: To evaluate the prevalence of beta-lactamase-non-producing ampicillin-resistant strains of H. influenzae with mutations in the ftsI gene encoding penicillin-binding protein 3 (PBP3) among children with otitis media. MATERIAL AND METHODS: A total of 644 nasopharyngeal isolates of H. influenzae were collected from pediatric acute otitis media patients with or without otitis media with effusion at the clinics of the Department of Otolaryngology-Head and Neck Surgery, Wakayama Medical University Hospital and 6 affiliated hospitals in Wakayama Prefecture between January 1999 and December 2003. MICs to ampicillin (AMP), cefdinir (CFD), cefaclor (CCL), cefpodoxime (CPD) and cefcapene (CFPN) were determined by a microbroth dilution method according to the recommendations of the National Committee for Clinical Laboratory Standards. Types of mutations in the PBP3 gene (ftsI) were evaluated by means of a polymerase chain reaction (PCR)-based genotyping method. The beta-lactamase gene (bla) was also identified by means of PCR. RESULTS: Beta-lactamase-producing (BLP) strains having the bla gene were identified in 16 isolates (2.5%). PGM strains were identified in 279 isolates (43.3%). There were 242 PGM1-non-BLP strains (37.6%) with mutations in the variable mutated locus of ftsI, 35 PGM2-non-BLP strains (5.4%) with mutations in the highly mutated locus of ftsI and 2 BLP-PGM strains (0.3%) with mutations in ftsI that produced beta-lactamase. BLP-non-PGM strains producing beta-lactamase without mutations in ftsI were identified in 14 isolates (2.2%). MICs of PGM1-non-BLP strains to AMP were 0.5-2.0 microg/ml. The MIC90 of CDN to the PGM1-non-BLP strains was the lowest (0.06 microg/ml). The proportion of PGM1-non-BLP strains increased rapidly during 1999-2002 and then decreased in 2003. In contrast, the proportion of PGM2-non-BLP strains increased in 2003.

Acute Disease↗

PubMed2006

Functions of tonsils in the mucosal immune system of the upper respiratory tract using a novel animal model, Suncus murinus.

CONCLUSION: The human palatine tonsils and the nasopharyngeal tonsil were considered the defense mechanism against ingested or inhaled foreign pathogens. The current findings suggest that the tubal tonsils possess abilities of active transportation of foreign antigens, and will act as inductive and effector sites in the mucosal immune system. Our results also indicated a significant difference in roles of immune responses among individual tonsillar organs, suggesting functional sub-compartmentalization. OBJECTIVES: To address the function of tonsils in inducing local immune responses, we evaluated the antigen uptake of tubal tonsils and the induction of specific immune responses in a small laboratory animal with both tubal and palatine tonsils, i.e. Suncus murinus. MATERIALS AND METHODS: S. murinus were injected with 2 x 10(6) CFU of FITC-labeled Staphylococcus aureus via the right tympanic cavity. The distribution of the FITC-labeled S. aureus was examined under a fluorescent microscope. S. murinus were also immunized with 100 microg of ovalbumin (OVA) mixed with 2 microg of cholera toxin (CT) via the right external ear meatus every 2 days for 2 weeks. One week after the final immunization, sera, pairs of tubal and palatine tonsils, and the neck lymph nodes were obtained to evaluate the induction of specific immune responses. RESULTS: The FITC-labeled S. aureus particles were detected in tubal tonsils and also in cervical lymph nodes. Total IgA-producing cells and OVA-specific antibody-producing cells were identified in the immunized tubal tonsils. Trans-external ear meatus immunization of tubal tonsils also evoked systemic antibody responses.

Adenoids↗

PubMed2006

Cost-effectiveness of tonsillectomy for recurrent acute tonsillitis.

OBJECTIVES: We used a retrospective case series to perform a preliminary study to determine the clinical effectiveness and cost-effectiveness of tonsillectomy for recurrent acute tonsillitis. METHODS: We studied 25 children and 16 adults who had tonsillectomy for recurrent acute tonsillitis. The adult patients and the children's caregivers were asked to respond to a questionnaire regarding the efficacy of their tonsillectomy. The cost of medical care and the work disability cost for tonsillitis and for tonsillectomy were calculated. We then applied the technique of break-even time analysis to assess when the total health care cost savings from surgery overtook the total cost of tonsillectomy. RESULTS: In children, the overall economic costs (medical costs and work-related costs) were recovered at 1.6 years after tonsillectomy (break-even point). In adults, the overall economic costs (medical costs and work-related costs) were recovered at 2.5 years after tonsillectomy (break-even point). CONCLUSIONS: Tonsillectomy for recurrent acute tonsillitis is both clinically effective and cost-effective for children and adults in Japan.

Acute Disease↗

PubMed2005

Tonsillitis index: an objective tool for quantifying the indications for tonsillectomy for recurrent acute tonsillitis.

This report is a preliminary exploration of the concept of a "Tonsillectomy Index" (TI) as an objective tool for quantifying the indications for tonsillectomy for recurrent acute tonsillitis (AT). The TI is derived by multiplying the number of episodes of AT by the number of years during which the episodes of AT occurred. Our objective in this study was to investigate whether there is a relationship between the natural history of AT, the immunological functions of tonsils and our proposed TI. For the natural history of AT, we medically followed 11 children with a history of AT for 5 years. When TI was equal to or greater than 8 (TI> or =8), the children suffered a significantly greater number of episodes of AT. For the immunological portion of our study, we enrolled 36 children and 46 adults undergoing tonsillectomy for either AT (study group) or tonsillar hypertrophy (control group, CG). We analyzed the co-stimulatory signals, CD80 and CD86 on tonsillar B-lymphocytes. The expression rates of CD80 and CD86 in the AT group with TI> or =8 were significantly decreased compared to those with TI was less than 8 (TI<8), as well as with those in control (tonsillar hypertrophy) group. Our preliminary findings suggest that when the TI> or =8, the tonsils have deteriorated immunologically and spontaneous resolution of recurrent AT is less likely to occur, hence tonsillectomy is appropriate. TI may be a useful tool for surgical decision making.

Acute Disease↗

PubMed2005

A recombinant P4 protein of Haemophilus influenzae induces specific immune responses biologically active against nasopharyngeal colonization in mice after intranasal immunization.

Outer membrane protein P4, together with P6, is highly conserved among all typeable and nontypeable strains of Haemophilus influenzae (H. influenzae). Thus, the protein is an attractive antigen for the inclusion in a vaccine against nontypeable H. influenzae (NTHi). However, the ability of P4 to induce antibodies protective against NTHi infections is still controversial. In this study, we investigated the specific mucosal immune responses against NTHi induced by intranasal immunization with the lipidated form of recombinant P4 protein (rP4) and non-fatty acylated recombinant P6 protein (rP6) with or without cholera toxin (CT) in BALB/c mice model. Intranasal immunization with either rP4+CT, a mixture of rP4 and rP6+CT, or rP4 and rP6 without CT elicited anti-rP4 specific IgG antibody in serum of mice. Intranasal immunization with either rP4+CT or a mixture of rP4, rP6+CT elicited anti-rP4 specific IgA antibody in nasopharyngeal washing (NPW), while intranasal immunization with rP4 and rP6 without CT did not induced anti-rP4 specific IgA antibody responses in NPWs. Sera from mice intranasally immunized with rP4+CT and a mixture of rP4, rP6+CT also showed bactericidal activity. Significant clearance of NTHi in nasopharynx was seen 3 days after the inoculation of live NTHi in mice intranasally immunized with rP4+CT. The current findings suggested that P4 would be a useful antigen as the component of the vaccine to induce protective immune responses against NTHi. The use of an intranasal vaccine composed of the different surface protein antigens is an attractive strategy for the development of a vaccine against NTHi.

Adjuvants, Immunologic↗

PubMed2005

Current status of antimicrobial susceptibility of clinical isolates of Streptococcus pyogenes in Japan: report of a countrywide surveillance study.

The growing number of macrolide-resistant strains of Streptococcus pyogenes is an increasing problem worldwide. In this study, we evaluated 62 clinical isolates of S. pyogenes obtained from the upper respiratory tract. Susceptibilities to penicillins, cephalosporins, fluoroquinolones, macrolides, and carbepenems were determined by minimal inhibitory concentrations (MICs). Expressions of macrolide-resistance genes (mefA, ermB, and ermTR) were also examined, by polymerase chain reaction (PCR). All strains were susceptible to beta-lactams. On the other hand, of the 62 S. pyogenes isolates, 6.5%, 6.5%, 6.5%, and 3.2% of the strains were resistant to azithromycin (AZM), roxithromycin (RXM), clarithromycin (CAM), and telithromycin (TEL), respectively. Four (6.5%) strains had a type of macrolide-resistance gene; there were two strains with ermB and two strains with ermTR, and these four strains were resistant to AZM, CAM (one strain was intermediately resistant), and RXM. Strains having ermB were resistant to TEL (MIC, > or = 8 microg/ml), while strains having ermTR were susceptible to TEL. Physicians and researchers need to take into consideration the macrolide resistance of some strains of S. pyogenes.

Anti-Bacterial Agents↗

PubMed2005

Evaluation of mutations in penicillin binding protein-3 gene of non-typeable Haemophilus influenzae isolated from the nasopharynx of children with acute otitis media.

CONCLUSION: Younger children tend to harbor more resistant strains because they are exposed to these pathogens more often through contacts with siblings or attendance at day-care centers and are frequently treated with antibiotics. The high prevalence of BLNAR strains should be taken into account in the treatment of AOM in young children. OBJECTIVE: Non-beta-lactamase-producing ampicillin-resistant (BLNAR) strains with mutations in penicillin-binding protein (PBP) genes of Haemophilus influenzae have been prevalent recently among younger children. MATERIAL AND METHODS: We investigated mutations in the ftsI gene encoding PBP-3 of H. influenzae isolated from the nasopharynx of children with acute otitis media (AOM) using polymerase chain reaction (PCR). RESULTS: Strains containing the bla gene (beta-lactamase-producing ampicillin-resistant) were identified in 4.7% of cases. Strains with mutations in the ftsI gene (BLNAR) were identified in 23.3% of cases. Strains without mutations in the ftsI gene and that did not contain the bla gene (non-beta-lactamase-producing ampicillin-susceptible) were identified in 70.7% of cases. Strains with both expression of the bla gene and mutations in the ftsI gene (beta-lactamase-producing amoxicillin clavulanate-resistant) were identified in 1.3% of cases. The MICs of ampicillin against the strains evaluated in this study were 0.5-2.0 microg/ml. Cefditoren-pivoxil had the lowest MIC90 against the strains (0.06 microg/ml). Strains with mutations in the ftsI gene (BLNAR) were broadly identified among young children.

Acute Disease↗

PubMed2005

Rapid diagnosis of pneumococcal meningitis: implications for treatment and measuring disease burden.

BACKGROUND: Streptococcus pneumoniae is the leading cause of childhood pneumonia and meningitis worldwide. Isolation of this organism, however, is uncommon in resource-poor countries, in part because of extensive use of prior antibiotics. A rapid, highly sensitive immunochromatographic test (ICT) for S. pneumoniae was evaluated for the diagnosis of meningitis. METHODS: Cerebrospinal fluid (CSF) from 450 children with suspected meningitis was tested with ICT, and results were compared with CSF culture, latex agglutination test (LAT) and/or polymerase chain reaction (PCR). Serial CSF specimens from 11 patients were also evaluated for duration of positive results during effective antimicrobial therapy. FINDINGS: All 122 cases of pyogenic pneumococcal meningitis positive either by culture (N = 87) or PCR (N = 35) were positive by ICT, yielding 100% (122 of 122) sensitivity. All purulent CSF specimens from patients with meningitis caused by other bacteria by culture (N = 149) or by LAT (N = 48) or those negative by culture, LAT and LytA and thus of unknown etiology (N = 20), and normal CSF specimens (N = 104) were negative by ICT. Thus the specificity of ICT also was 100% (321 of 321), although negativity of ICT was not confirmed by PCR, if it was positive for other organisms either by culture or LAT. Serotyping of S. pneumoniae strains revealed 28 different serotypes, indicating that outcome of ICT are independent of diverse capsular serotype of pneumococcus. Antigen was detected by ICT for at least 10 days after presentation, and 1 was still positive on day 20, which was longer than for either LAT or PCR. INTERPRETATION: ICT for pneumococcal antigen in CSF is 100% sensitive and specific in diagnosing pyogenic pneumococcal meningitis and can detect approximately 30% more pneumococcal meningitis cases than with culture alone. The simplicity of the test procedure and the longevity of CSF antigen detection suggest the potential utility of ICT to estimate the true burden of pneumococcal disease, as for Haemophilus influenzae type b using data from meningitis, and to guide selection of appropriate antibiotic treatment, especially in resource-poor countries with widespread prehospital antimicrobial use.

Antigens, Bacterial↗