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Journal of Clinical Microbiology, May 2007, p. 1440-1446, Vol. 45, No. 5
0095-1137/07/$08.00+0     doi:10.1128/JCM.01430-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Genotypes and Related Factors Reflecting Macrolide Resistance in Pneumococcal Pneumonia Infections in Japan{triangledown}

Rie Isozumi,1 Yutaka Ito,1* Tadashi Ishida,2 Makoto Osawa,1 Toyohiro Hirai,1 Isao Ito,1,3 Ko Maniwa,4 Michio Hayashi,5 Hitoshi Kagioka,6 Masataka Hirabayashi,7 Koichi Onari,8 Hiromi Tomioka,9 Keisuke Tomii,5,10 Iwao Gohma,10 Seiichiro Imai,1 Shunji Takakura,11 Yoshitsugu Iinuma,11 Satoshi Ichiyama,11 Michiaki Mishima,1 and the Kansai Community Acquired Pneumococcal Pneumonia Study Group {dagger}

Department of Respiratory Medicine,1 Department of Clinical Laboratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan,11 Kurashiki Central Hospital, Okayama, Japan,2 Ono Municipal Hospital, Hyogo, Japan,3 Tenri Hospital, Nara, Japan,4 Kobe City General Hospital, Hyogo, Japan,5 Kitano Hospital, Osaka, Japan,6 Hyogo Prefectural Tsukaguchi Hospital, Hyogo, Japan,7 Sakai Municipal Hospital, Osaka, Japan,8 Nishi-Kobe Medical Center, Hyogo, Japan,9 Kobe Japan Post Hospital, Hyogo, Japan,10

Received 11 July 2006/ Returned for modification 26 August 2006/ Accepted 9 February 2007


   ABSTRACT
Top
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Although macrolide-resistant Streptococcus pneumoniae strains possessing either the ermB or mefA gene are very common in Japan, clinical and microbial factors in community-acquired pneumonia (CAP) caused by different macrolide resistance genotypes have not been evaluated. A multicenter study of CAP caused by S. pneumoniae was performed in Japan from 2003 to 2005. A total of 156 isolates were tested for susceptibility to antibiotics correlated with ermB and mefA genotyping. Independent relationships between tested variables and possession of either the ermB or the mefA gene were identified. Of 156 isolates, 127 (81.4%) were resistant to erythromycin, with the following distribution of resistance genotypes: ermB alone (50.0%), mefA alone (23.7%), and both ermB and mefA (7.1%). All isolates were susceptible to telithromycin. By multivariate analysis, oxygen saturation of <90% on admission increased the risk for ermB-positive pneumococcal pneumonia (odds ratio [OR] = 11.1; 95% confidence interval [CI] = 1.30 to 95.0; P = 0.03), but there were no associations with mefA or with ermB mefA positivity. Penicillin nonsusceptibility was associated with mefA-positive and with ermB- and mefA-positive isolates (OR = 14.2; 95% CI = 4.27 to 46.9; P < 0.0001 and P < 0.0001, respectively) but not with ermB-positive isolates. The overall patient mortality was 5.1%. Mortality, the duration of hospitalization, and the resolution of several clinical markers were not associated with the different erythromycin resistance genotypes. In Japan, S. pneumoniae with erythromycin resistance or possession of ermB, mefA, or both genes was highly prevalent in patients with CAP. The risk factors for ermB-positive, mefA-positive, and double ermB-mefA-positive pneumococcal pneumonia were different, but the clinical outcomes did not differ.


   INTRODUCTION
Top
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Streptococcus pneumoniae is a leading cause of community-acquired pneumonia (CAP). Although medical practice guidelines for the treatment of CAP, especially in outpatients without significant comorbidities, recommend macrolides as first-line agents (20), S. pneumoniae macrolide resistance has increased within the past decade worldwide. Thus, several large surveillance studies have shown that frequency of resistance has increased from 19% in 1997 to 31% in 2000 (6, 7, 10).

Resistance to macrolides occurs primarily through two mechanisms: ribosomal modification (MLSb phenotype) or active drug efflux (M phenotype) (19). The former mechanism, depending on gene products encoded by ermB, methylates adenine residues in domain V of 23S rRNA. The latter depends on mefA. The MLSb phenotype is typically highly resistant to macrolides (i.e., an erythromycin MIC of >64 µg/ml) and is prevalent in Europe and South Africa, whereas the M phenotype results in an intermediate level of resistance (an erythromycin MIC of 1 to 32 µg/ml) and predominates in North America (19). The occurrence of macrolide-resistant S. pneumoniae is high in Asia (12, 29) and reaches 68 to 78% in Japan (12, 29). The rates of ermB-positive, mefA-positive, ermB- and mefA-positive (double positive), and ermB- and mefA-negative (double negative) strains in Japan were reported to be 36 to 41%, 27 to 37%, 1 to 3%, and 22 to 31%, respectively (12, 24, 34).

Several risk factors for macrolide resistance in S. pneumoniae have been reported (8, 21), but most studies were concerned with the acquisition or carriage of resistant strains. Recent studies have defined risk factors for macrolide resistance in pneumococcal pneumonia and invasive infections. These included previous hospital admission, penicillin resistance, advanced age, a higher pneumonia severity index (PSI) score, human immunodeficiency virus infection, and previous penicillin or macrolide use (1, 30, 35). Risk factors for antimicrobial resistance are useful for avoiding inappropriate therapy. However, some researchers have questioned whether resistance to macrolides is clinically relevant because high concentrations of such agents can be achieved in the lung (25). Clinical failures in pneumonia can be expected with highly resistant ermB-positive strains (23). A previous report differentiated the risk factors in patients with invasive diseases based on the M or MLSb phenotype. It was found that the M phenotype was more common among patients <5 years of age and in Caucasians, but penicillin nonsusceptibility was associated with both phenotypes (11).

In order to establish the prevalence of macrolide-resistant S. pneumoniae in CAP patients and to understand the differences of clinical and microbial factors for CAP caused by highly resistant S. pneumoniae possessing ermB compared to S. pneumoniae with intermediate resistance possessing mefA, we conducted a prospective multicenter study in Japan.


   MATERIALS AND METHODS
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Design of the research. From May 2003 through February 2005, a multicenter, observational, prospective study was done in Japan. Ten hospitals in the Kansai Community Acquired Pneumococcal Pneumonia Study Group participated in this study: Kurashiki Central Hospital (30 patients), Kobe Japan Post Hospital (2 patients), Nishi-Kobe Medical Center (9 patients), Kobe City General Hospital (19 patients), Kitano Hospital (16 patients), Hyogo Prefectural Tsukaguchi Hospital (14 patients), Sakai Municipal Hospital (9 patients), Tenri Hospital (20 patients), Kyoto University Hospital (12 patients), and Ono Municipal Hospital (25 patients). Patients over 15 years old diagnosed with CAP caused by S. pneumoniae were included. A total of 156 cases was enrolled. The study was approved by the ethics committees of each hospital.

Clinical and microbiological diagnosis. Diagnostic criteria for pneumococcal pneumonia in the present study included the following: (i) radiographic evidence of a pulmonary infiltrate that was neither preexisting nor had any other known cause, (ii) the presence of at least one of the several conditions (i.e., febrile status, cough, sputum, chest pain, dyspnea, and rale on chest exploration), and (iii) microbiological diagnosis of pneumococcal pneumonia as a positive culture from blood, transtracheal aspiration, bronchoalveolar lavage (cutoff point of >105 CFU/ml), or sputum with comparable Gram stain or culture findings.

Data collection. We collected the clinical data on a standardized case report form. It included sociodemographic characteristics, underlying conditions and diseases, a history of antibiotic use (including low-dose macrolide therapy within the 3 months before presentation at the hospital), clinical manifestations, laboratory results, antimicrobial therapy, clinical course, and death. On the basis of these data, the clinical severity of pneumococcal pneumonia was assessed by means of the PSI (20). Patients were classified into risk classes of 1 to 5 on the basis of the PSI score.

Antimicrobial susceptibility testing of bacteria. All isolates were stored at –80°C, and the MIC of each antibiotic was determined by the microdilution method at a central laboratory (Mitsubishi BCL, Inc., Tokyo, Japan). The following six agents were tested: penicillin, erythromycin, azithromycin, clarithromycin, telithromycin, and clindamycin. Susceptibility or resistance of pneumococci to these antimicrobial agents was assessed in accordance with the recommendations of the National Committee for Clinical Laboratory Standards in 2004 (22).

Detection of macrolide resistance genes. Typing for ermB and/or mefA was performed by PCR with primers described previously (31).

Serotyping. All isolates were serotyped by the capsular Quellung method with commercial antisera (Statens Seruminstitut, Copenhagen, Denmark).

PFGE. The serotype 3 S. pneumoniae isolates were tested by pulsed-field gel electrophoresis (PFGE), which was performed as described previously (17). Briefly, plugs were digested with SmaI. The fragments of chromosomal DNA were separated with the GenePath strain typing system (Bio-Rad, Hercules, CA) and stained with ethidium bromide. Interpretation of strain relatedness on the basis of PFGE patterns was done according to accepted criteria (33).

Statistical analysis. Statistical analysis was performed by using StatView version 5.0. Risk factors and outcomes for macrolide resistance genotypes were identified by comparison of double ermB- and mefA-negative genotypes. Odds ratios (OR) and 95% confidence intervals (CI) were computed as an estimate of the relative risk. Clinical manifestations and disease severity were compared between each genotype by using the Student t test, {chi}2 analysis, or the Fisher exact test. Multiple logistic regression analysis was done for variables associated with macrolide resistance genotypes by univariate analysis (P < 0.25). A P value of <0.05 was considered to be statistically significant.


   RESULTS
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Patient characteristics. A total of 156 adult patients was assessed (106 [67.9%] males and 50 [32.1%] females, aged 67.4 ± 14.7 years [range, 18 to 96 years]). At least one comorbid illness was present in 113 of these patients: chronic pulmonary disease in 57 (36.5%), chronic heart disease in 21 (13.5%), diabetes mellitus in 22 (14.1%), chronic liver disease in 14 (9.0%), chronic renal disease in 4 (2.6%), neurological disease in 13 (8.3%), neoplastic disease in 12 (7.7%), and systemic corticosteroid use in 14 (9.0%). Hospital admission was necessary for 85 patients (54.5%), and 71 (45.5%) were treated as outpatients with or without brief hospitalization. The numbers of subjects in each PSI class were as follows: class I, 16 (10.3%); class II, 40 (25.6%); class III, 43 (27.6%); class IV, 42 (26.9%); and class V, 15 (9.6%). None of the patients had received 23-valent pneumococcal vaccine.

Antimicrobial susceptibilities. The overall resistance rates to erythromycin, clarithromycin, and azithromycin were 81.4, 76.9, and 78.8%, respectively. All clindamycin-resistant isolates (n = 83 [53.2%]) were also resistant to erythromycin (MLSb phenotype). Among erythromycin-resistant isolates, the MLSb and M phenotypes made up 65.4% (83 isolates) and 34.6% (44 isolates), respectively. All isolates were susceptible to telithromycin (Table 1).


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  		TABLE 1. Susceptibility of 156 S. pneumoniae isolates to 5 antibiotics

 
Distribution of ermB and mefA genes. The distribution of macrolide resistance genes is shown in Fig. 1. The rates of ermB-positive, mefA-positive and double ermB- and mefA-positive isolates in erythromycin-resistant S. pneumoniae were 61.9, 29.4, and 8.7%, respectively. Among MLSb phenotypes, 73 (88.0%), 1 (1.2%), and 9 (10.8%) isolates were ermB positive, mefA positive, and double positive, respectively. Among M phenotypes, 4 (9.1%), 36 (81.8%), 2 (4.5%), and 2 (4.5%) isolates were ermB positive, mefA positive, double positive, and double negative, respectively. The rate of erythromycin resistance in ermB- and mefA-negative isolates was 6.7%. The ranges of erythromycin MICs for ermB-positive, mefA-positive, and double-positive S. pneumoniae were 0.06 to >128 mg/liter (MIC90 [i.e., the MIC at which 90% of the isolates tested are inhibited] of >128 mg/liter), 1 to 16 mg/liter (MIC90 of 4 mg/liter), and 4 to >128 mg/liter (MIC90 of >128 mg/liter), respectively. All isolates were susceptible to telithromycin, irrespective of the ermB or mefA genotype. The ranges of telithromycin MICs for ermB-positive, mefA-positive, double-positive, and double-negative S. pneumoniae were 0.06 to 1 mg/liter (MIC90 of 0.12 mg/liter), 0.06 to 1 mg/liter (MIC90 of 0.12 mg/liter), 0.06 to 1 mg/liter (MIC90 of 0.5 mg/liter), and 0.06 mg/liter (MIC90 of ≤0.06 mg/liter), respectively.


Figure 1
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  		FIG. 1. MIC distribution and association with macrolide resistance genes. The percentages of isolates are shown. (A) Erythromycin; (B) telithromycin.

 
Serotypes. Of 156 isolates, the more common serotypes were 3, 19F, 23F, 6B, 14, and 23A (Table 2). Among serotype 3 isolates, the numbers of erythromycin-resistant, ermB-positive, and penicillin-susceptible ermB-positive isolates were 40 (95.2%), 39 (92.9%), and 38 (90.5%), respectively. All serotype 19F isolates were erythromycin resistant. Seven (63.6%) of eleven double-positive isolates were serotype 19F or 23F.


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  		TABLE 2. Serotype distribution of 156 pneumococcal isolates from community-acquired pneumonia in Japan

 
PFGE. PFGE analysis showed that 37 isolates were indistinguishable, and a further two isolates were closely related among the 42 serotype 3 isolates (Fig. 2). Among the 39 clone strains, 38 were penicillin susceptible and ermB positive. The clone strains were isolated from all hospitals.


Figure 2
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  		FIG. 2. PFGE patterns of SmaI restriction digests of 42 serotype 3 isolates. The numbers identifying the participating hospitals are given at the top of the figure. Hospitals: 1, Kurashiki Central Hospital; 2, Kobe Japan Post Hospital; 3, Nishi-Kobe Medical Center; 4, Kobe City General Hospital; 5, Kitano Hospital; 6, Hyogo Prefectural Tsukaguchi Hospital; 7, Sakai Municipal Hospital; 8, Tenri Hospital; 9, Kyoto University Hospital; 10, Ono Municipal Hospital. {lambda} denotes the {lambda} marker. Patterns A, B, C, and D are unrelated. Patterns A1, A2, and A3 are closely related.

 
Factors associated with possession of ermB and/or mefA genes. The factors for isolates possessing ermB alone, mefA alone, and both ermB and mefA compared to S. pneumoniae isolates without ermB and mefA genes are presented in Table 3. By multivariate analysis, isolates possessing ermB alone were more likely to be detected in patients with an oxygen saturation (SpO2) of <90% on admission (OR = 11.1, 95% CI = 1.30 to 95.0, P = 0.03). The isolates possessing the mefA gene or both ermB and mefA genes were not associated with an SpO2 of <90% on admission (P = 0.23 and P = 0.65, respectively). The frequency of high PSI scores (PSI class IV or V) in patients with ermB-positive, mefA-positive, or double-positive isolates was similar in patients with neither (P = 0.96, P = 0.90, and P > 0.99, respectively). Penicillin nonsusceptibility was not associated with ermB positivity of the isolates (P = 0.94), whereas it was strongly associated with mefA positivity (OR = 14.2, 95% CI = 4.27 to 46.9, P < 0.0001) by multivariate analysis. Ten double-positive isolates were penicillin nonsusceptible (90.9%, P = 0.0009) (Table 3).


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  		TABLE 3. Factors associated with possession of ermB or mefA in Streptococcus pneumoniae

 
Outcomes of CAP caused by ermB- or mefA-positive S. pneumoniae. Total mortality was 5.1%. There were no statistically significant associations between mortality and the ermB or mefA genotypes. Duration to normalization of body temperature, the C-reactive protein value, and the white blood cell counts were also not associated with these genotypes (Table 4). Among 13 outpatients treated with oral macrolide monotherapy, 10 received discordant therapy (7, ermB positive; 3, mefA positive). However, there were no deaths and no microbiological treatment failures.


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  		TABLE 4. Clinical outcomes for each genotype

 

   DISCUSSION
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
Macrolide resistance in S. pneumoniae in Japan is now very common and is mediated predominantly by the ermB gene (12, 24, 34). In the present study, 81.4% of isolates were found to be erythromycin resistant, and 50.0% possessed the ermB gene. These values are considerably higher than in previous reports (12, 24, 34). Recent surveillance exercises, ANSORP 1996-1997 (29) and PROTEKT 1999-2000 (12), found that the rates of macrolide resistance in S. pneumoniae in Japan reached 67.9 and 77.9%, respectively. A possible reason for the high levels of resistance that we found is the source of our isolates, which were from CAP patients, especially from sputum and bronchoalveolar lavage. Resistance rates in isolates from respiratory tract infection are higher than in isolates from other sources, such as blood (9). The frequency of double ermB- and mefA-positive macrolide-resistant S. pneumoniae increased from 9.7 to 16.4% in the PROTEKT U.S. surveillance study (PROTEKT 2000-2003) (5) and was 38.4% in South Korea (12). In our study, the double-positive isolates increased in frequency compared to previous reports from Japan (12, 24, 34), but the frequency was lower than in the United States or South Korea (8.7% in erythromycin-resistant S. pneumoniae).

Telithromycin has a higher binding affinity to domains II and V of 23S rRNA than macrolides and has high activity against clinical isolates of macrolide-resistant S. pneumoniae with ermB or mefA genes (16). Only 10 telithromycin-resistant strains (0.07%) were isolated among 18,374 strains collected in PROTEKT 1999-2003 (4). High-level telithromycin resistance was generated experimentally by mutation in domain II or V of 23S rRNA and ribosomal protein L4 or L22 (16) and was easily generated from ermB- or mefA-resistant strains with a telithromycin MIC of 1 mg/liter (37). All isolates in our study were susceptible to telithromycin (MIC of ≤1 mg/liter), but three isolates (1.9%) had a telithromycin MIC of 1 mg/liter. This frequency is higher than in the PROTEKT 1999-2003 study (0.8% for an MIC of ≥1 mg/liter) (4). Double ermB- and mefA-positive S. pneumoniae in Far Eastern Asia showed low-level telithromycin susceptibility (MIC = 0.12 to 1 mg/liter; MIC90 = 0.5 mg/liter) (12). In our study, 11 double ermB- and mefA-positive isolates also had low-level telithromycin susceptibility (MIC = 0.06 to 1 mg/liter; MIC90 = 0.5 mg/liter) and greater resistance than solely ermB-positive isolates or solely mefA-positive isolates (MIC = 0.06 to 1 mg/liter; MIC90 = 0.12 mg/liter).

Reported risk factors for macrolide-resistant S. pneumoniae, such as the previous use of antibiotics and hospital admission, were not confirmed in our study. Although Song et al. reported that older age and, as a result, higher PSI scores, were independent predictors of erythromycin-resistant pneumococcal pneumonia (30), age and PSI score were not associated with the presence of macrolide resistance genes in our study. This was probably because of the high prevalence of erythromycin-resistant S. pneumoniae among CAP patients with each genotype. Several previous reports have shown that penicillin nonsusceptibility was associated with erythromycin-resistant pneumococcal pneumonia, independently of the M or MLSb phenotype (1, 11, 35). In our study, mefA-positive and double-positive pneumococcal pneumonia was significantly associated with penicillin nonsusceptibility, whereas ermB positivity was not. The latter may be due to the lack of statistical power, but the differences in the rates of penicillin nonsusceptibility among ermB-positive, mefA-positive, and double-positive S. pneumoniae were significant (30.8, 78.4, and 90.9%, respectively). Furthermore, cardiopulmonary disease tended to be, and an SpO2 of <90% on admission was, significantly associated with ermB-positive, but not with mefA-positive and double-positive, pneumococcal pneumonia. Chronic pulmonary disease (1) and chronic obstructive pulmonary disease (COPD) (2) were risk factors for penicillin-resistant pneumococcal pneumonia and for the acquisition of multidrug-resistant S. pneumoniae because these patients were likely to be hospitalized and to receive antibiotics. Thus, our contrasting results were quite intriguing, whereby ermB-positive isolates from patients with clinical risk factors were more susceptible to penicillin than mefA-positive and double-positive isolates.

One recent report has documented the clonal spread of macrolide-resistant and penicillin-susceptible serotype 3 strains in Japan (14). Because the penicillin-susceptible ermB-positive serotype 3 clone strains were also isolated from all participating hospitals in our study, these strains are likely to be widespread in Japan.

Increased use of macrolides has suggested a link to increased rates of pneumococcal resistance. In Portugal, the emergence of erythromycin-resistant strains, especially serotype 14, correlated with the use of azithromycin (3). Since the efficacy of long-term macrolide therapy for diffuse panbronchiolitis has been established, this has been widely introduced in Japan for diffuse panbronchiolitis and other relevant diseases, such as bronchiectasis and cystic fibrosis (28). A recent study showed that patients who received long-term clarithromycin therapy were prone to be carriers of MLSb type S. pneumoniae (13). A report from Japan showed that erythromycin therapy prevented exacerbation in COPD patients (32). Patients with chronic pulmonary diseases are likely to be prescribed macrolides in Japan. Thus, the reason why an SpO2 of <90% on admission was significantly associated with ermB-positive but not mefA-positive pneumococcal pneumonia and why cardiopulmonary diseases tended to be associated may be the selection of ermB-positive strains by overuse of macrolides or the clonal spread of the serotype 3 strains in these patients. Prior vaccination, as well as the regulation of macrolide use, is likely to be effective in decreasing the spread of ermB-positive strains.

Double ermB- and mefA-positive strains exhibited multidrug resistance, including resistance to penicillin, and were clonally related to Taiwan19F-14 clonal complex 236 (CC236), 271 (CC271), Taiwan23F-15 (CC242), and Spain23F-1 (CC81) (15). In our study, most of the double-positive isolates were also penicillin resistant (90.9%) and serotype 19F or 23F (63.6%). Thus, these isolates are also likely to be single clones. However, we could not identify clinical correlates for the double-positive isolates because of the relatively small population tested.

Macrolide resistance is associated with treatment failure in patients with bacteremia, irrespective of full or intermediate resistance (18, 27). In contrast, clinical failures in treating pneumonia can be expected with highly resistant ermB-positive strains because macrolide agents achieve high concentrations in the lung (25). However, our data did not show any correlation between mortality and macrolide-resistant genotypes. Other outcome indicators reported previously, such as the duration of hospital stay, body temperature, white blood cell counts (36), or C-reactive protein levels (26), were not significant in our study either. This was probably because mortality is an insensitive measure of treatment outcome and because the overall mortality, as well as the number of cases of severe pneumonia, in our study was too low (mortality, 5.1%; PSI class IV/V, 36.5%). Furthermore, only 10 patients received discordant therapy of oral macrolides, and all of them were treated at outpatient clinics with no treatment failures.

There are certain limitations to our study. First, our sample size was not sufficiently large to identify various risk factors. However, even in a larger study, the association of penicillin nonsusceptibility with ermB positivity would be likely to be weaker than with mefA positivity because unique serotype 3 clone strains are prevalent in Japan. Furthermore, other risk factors reported previously such as prior use of macrolides or previous hospitalization may not be significant because of the high prevalence of macrolide-resistant S. pneumoniae in Japan. The second limitation of the present study is the low rate of severe disease and mortality. Third, number of patients on macrolide monotherapy was small. Therefore, it was not possible to identify any significant associations between the severity, prognosis, or clinical impact of macrolide therapy and the different genotypes of macrolide-resistant pneumococcal pneumonia.

In summary, this is the first prospective multicenter study on the surveillance of macrolide resistance genotyping correlated with clinical factors in pneumococcal pneumonia. Macrolide-resistant S. pneumoniae isolates possessing ermB, mefA, or both genes were very common. Penicillin-susceptible ermB-positive isolates were also extremely common, and these were clonal strains. The risk factors for ermB- and mefA-positive pneumococcal pneumonia were different, namely, an SpO2 of <90% on admission and penicillin nonsusceptibility, respectively. Thus, in geographical areas where some resistant genotypes or clonal strains are very common, further surveillance is necessary to clarify risk factors.


   ACKNOWLEDGMENTS
 
The Kansai Community Acquired Pneumococcal Pneumonia Study Group received research funding from Pfizer, Inc., Abbott Japan Co., Ltd., and Taisho Toyama Pharmaceutical Co., Ltd. This presents a potential conflict of interest.


   FOOTNOTES
 
* Corresponding author. Mailing address: Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54, Kawahara, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan. Phone: 81-75-751-3830. Fax: 81-75-751-4643. E-mail: yutaka{at}kuhp.kyoto-u.ac.jp Back

{triangledown} Published ahead of print on 7 March 2007. Back

{dagger} Y. Ito, T. Ishida, T. Hirai, I. Ito, K. Maniwa, M. Hayashi, H. Kagioka, M. Hirabayashi, K. Onari, H. Tomioka, K. Tomii, I. Gohma, and M. Mishima are contributing members of the Kansai Community Acquired Pneumococcal Pneumonia Study Group. Back


   REFERENCES
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

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Journal of Clinical Microbiology, May 2007, p. 1440-1446, Vol. 45, No. 5
0095-1137/07/$08.00+0     doi:10.1128/JCM.01430-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



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