Kiwao Watanabe

Association between nasopharyngeal load of Streptococcus pneumoniae, viral coinfection, and radiologically confirmed pneumonia in Vietnamese children.

Background: The interplay between nasopharyngeal bacterial carriage, viral coinfection, and lower respiratory tract infections (LRTIs) is poorly understood. We explored this association in Vietnamese children aged less than 5 years. Methods: A hospital-based case-control study of pediatric LRTIs was conducted in Nha Trang, Vietnam. A total of 550 hospitalized children (274 radiologically confirmed pneumonia [RCP] and 276 other LRTIs) were enrolled and 350 healthy controls were randomly selected from the community. Polymerase chain reaction-based methods were used to measure bacterial loads of Streptococcus pneumoniae (SP), Haemophilus influenzae, and Moraxella catarrhalis and to detect 13 respiratory viruses and bacterial serotypes in nasopharyngeal samples of study participants. Results: The median nasopharyngeal bacterial load of SP was substantially higher in children with RCP compared with healthy controls or children with other LRTIs (P < 0.001). SP load was 15-fold higher in pneumonia children with viral coinfection compared with those children without viral coinfection (1.4 × 107/mL vs. 9.1 × 105/mL; P = 0.0001). SP load was over 200-fold higher in serotypeable SP compared with nontypeable SP (2.5 × 106/mL vs. 1 × 104/mL; P < 0.0001). These associations were independent of potential confounders in multiple regression models. No clear association was found between nasopharyngeal load of Haemophilus influenzae or Moraxella catarrhalis and viral coinfection in either RCP or other LRTIs groups. Conclusions: An increased load of SP in the nasopharynx was associated with RCP, viral coinfection, and presence of pneumococcal capsule.

Combination Therapy with Fluconazole and Flucytosine for Cryptococcal Meningitis in Ugandan Patients with AIDS

We performed a randomized trial in which combination therapy with fluconazole and short-term flucytosine was compared with fluconazole monotherapy in 58 patients with AIDS-associated cryptococcal meningitis (CM). Thirty of these patients were randomized to receive combination therapy with fluconazole, 200 mg once a day for 2 months, and flucytosine, 150 mg/(kg.d) for the first 2 weeks, and 28 were randomized to receive monotherapy with fluconazole at the same dose for 2 months. Patients in both groups who survived for 2 months received fluconazole as maintenance therapy at a dose of 200 mg three times per week for 4 months. The combination therapy prevented death within 2 weeks and significantly increased the survival rate among these patients (32%) at 6 months over that among patients receiving monotherapy (12%) (P = .022). The combination therapy also resulted in a significant decrease in the severity of headache after 1 month of treatment, compared with monotherapy (P = .005). No serious adverse reactions were observed in patients receiving either regimen. These data indicate that treatment with fluconazole and short-term flucytosine is a cost-effective and safe regimen that improves the quality of life for patients with AIDS-associated CM in developing countries where human immunodeficiency virus is endemic.

Emergence of Rifampin-Resistant Rhodococcus equi with Several Types of Mutations in the rpoB Gene among AIDS Patients in Northern Thailand

ABSTRACT The antimicrobial susceptibilities of 30 Rhodococcus equi isolates obtained from 30 patients between 1993 and 2001 in northern Thailand were investigated. The MICs showed a tendency toward resistance to various antibiotics but sensitivity to imipenem, minocycline, vancomycin, and teicoplanin (MICs, ≤0.5 μg/ml) and relative sensitivity to meropenem, clarithromycin, and ciprofloxacin (MICs, ≤2 μg/ml). Of the 30 isolates, 26 were susceptible (MICs, ≤1 μg/ml), 1 showed low-level resistance (MIC, 8 μg/ml), and 3 showed high-level resistance (MICs, ≥64 μg/ml) to rifampin. PCR amplification and DNA sequencing of the rpoB gene and molecular typing by pulsed-field gel electrophoresis (PFGE) were performed for eight R. equi isolates from eight AIDS patients with pneumonia or lung abscess caused by R. equi between 1998 and 2001, including one low- and three high-level rifampin-resistant isolates. As a result, two high-level rifampin-resistant strains with PFGE pattern A had a Ser531Trp (Escherichia coli numbering) mutation, and one high-level rifampin-resistant strain with PFGE pattern B had a His526Tyr mutation, whereas one low-level rifampin-resistant strain with PFGE pattern C had a Ser509Pro mutation. Four rifampin-susceptible strains with PFGE patterns D and E showed an absence of mutation in the rpoB region. Our results indicate the presence of several types of rifampin-resistant R. equi strains among AIDS patients in northern Thailand.

A comparative clinical study of pneumonia by penicillin-resistant and -sensitive Streptococcus pneumoniae in a community hospital.

This study aimed to determine the clinical difference of pneumonia between penicillin‐resistant and penicillin‐sensitive Streptococcus pneumoniae.

Low Concentrations of Mupirocin in the Pharynx following Intranasal Application May Contribute to Mupirocin Resistance in Methicillin-Resistant Staphylococcus aureus

ABSTRACT We describe a patient with methicillin-resistantStaphylococcus aureus (MRSA) colonizing the pharynx. The MIC of mupirocin was 0.25 μg/ml before treatment and increased after treatment to 8 μg/ml. Using pulsed-field gel electrophoresis, we confirmed that the genotypes of MRSA that colonized the pharynx before and after the use of mupirocin were identical. We measured the delivery of mupirocin to the pharynx in three normal volunteers and two patients. Low concentrations of mupirocin were present in the pharynx in all cases 10 min to 3 days after intranasal application. Our data suggested that low concentrations of the drug in the pharynx after intranasal application of mupirocin ointment might explain the selection of mupirocin resistance in MRSA.

High Rate of Transmission of Penicillin-Resistant Streptococcus pneumoniae between Parents and Children

ABSTRACT Transmission of Streptococcus pneumoniae between children and their parents was evaluated in 29 pairs from 25 families. The serotypes of 35 pneumococcal isolates from 18 (62.1%) of 29 child-parent pairs were identical. Of the 35 isolates, 23 showed intermediate resistance and 10 were fully resistant to penicillin G. PCR indicated that all 35 strains had at least one alteration in penicillin-binding protein genes pbp1a, pbp2x, and pbp2b and 33 strains had macrolide resistance genes mef(A) and/or erm(B). As a result, the PCR patterns of 16 of 18 pairs were identical. Molecular typing by pulsed-field gel electrophoresis showed that 12 pairs were indistinguishable, 3 pairs were closely related, 2 pairs were possibly related, and only one pair was different. Our data indicate the presence of a high rate of transmission of penicillin-resistant S. pneumoniae between children and their parents.

Possible High Rate of Transmission of Nontypeable Haemophilus influenzae, Including β-Lactamase-Negative Ampicillin-Resistant Strains, between Children and Their Parents

ABSTRACT The possible transmission of nontypeable Haemophilus influenzae between children and their parents was evaluated in 18 pairs of subjects from 15 families. Of the 33 isolates, 31 were found to be β-lactamase negative, including 10 β-lactamase-negative, ampicillin (AMP)-resistant (BLNAR) strains (AMP MIC, ≥1.0 μg/ml) and 2 were β-lactamase producing. Molecular typing by pulsed-field gel electrophoresis (PFGE) showed that 10 BLNAR isolates had 6 patterns, 23 non-BLNAR isolates had 13 patterns, and these patterns were different from each other, except for 1 pattern. As a result, the PFGE patterns in 14 of 18 pairs were indistinguishable and those in 4 pairs were different. These data indicate a possible high rate of intrafamilial transmission of nontypeable H. influenzae, including BLNAR strains, between children and their parents.

Drug-resistant genes and serotypes of pneumococcal strains of community-acquired pneumonia among adults in Japan

Background:  A high frequency of drug‐resistant pneumococci has been reported in Asian countries. Few data on the drug‐resistance or serotype of pneumococcal strains responsible for community‐acquired pneumonia (CAP), however, are available for the past two decades in Japan.

Therapeutic effects of a human antiflagella monoclonal antibody in a neutropenic murine model of Pseudomonas aeruginosa pneumonia.

Human immunoglobulin G1 (IgG1) monoclonal antibodies (MAbs) reactive with type-specific Pseudomonas aeruginosa lipopolysaccharide (LPS) and flagella were compared for their protective activities against Fisher immunotype 2 P. aeruginosa pneumonia in neutropenic mice. The activity of the antiflagella MAb at a dose of 500 micrograms per mouse was comparable to that of the anti-LPS MAb at the same dose. In vivo protection was correlated with bacterial density in the lung tissue and blood of infected mice. In vitro data suggested that the protective activity of the antiflagella MAb was due more to inhibition of bacterial motility than to opsonophagocytosis of bacteria by alveolar macrophages. In contrast, the protective activity of the anti-LPS MAb was primarily related to alveolar macrophage-mediated opsonophagocytosis. Antiflagella MAb at a dose of 500 micrograms combined with oral sparfloxacin at a subtherapeutic dose of 62.5 micrograms produced a significant increase in survival (P < 0.05) compared with that produced by either agent alone or no treatment. The additive effects between the antiflagella MAb and sparfloxacin at sub-MICs on the inhibitory effects of bacterial motility supported the in vivo effect of the combination. These data suggest that human isotype-matched antiflagella and anti-LPS MAbs have similar protective activities against Pseudomonas pneumonia in neutropenic mice, despite discrete mechanisms of antibody-matched protection. In addition, in vivo synergy was demonstrated between antiflagella MAb and sparfloxacin in this model.

Decreased Serum Opsonic Activity against Streptococcus pneumoniae in Human Immunodeficiency Virus—Infected Ugandan Adults

Type-specific immunoglobulin G (IgG) to pneumococcal capsular polysaccharide (CPS) and opsonic activity against Streptococcus pneumoniae were evaluated in serum samples from 36 Ugandan adults with community-acquired pneumonia and 58 asymptomatic Ugandan adults with or without human immunodeficiency virus type 1 (HIV-1) infection. The levels of serum IgG to CPS were significantly higher in HIV-1-infected subjects than in HIV-uninfected subjects. Serum samples from HIV-1-infected subjects that had lower IgG titers demonstrated higher opsonic activity against type 3 (titers of 7) and type 9 (titers of 7-11) pneumococcal strains. Plasma HIV-1 load also correlated inversely with serum opsonic activity against these strains, and peripheral blood CD4+ lymphocyte numbers also tended to correlate with serum opsonic activity in asymptomatic HIV-1-infected adults. Our findings suggest that the opsonic activity of type-specific IgG is impaired in the serum of HIV-1-infected African adults, which may expose them to a serious risk of invasive pneumococcal infections.