Prevalence, characteristics, and molecular epidemiology of macrolide and fluoroquinolone resistance in clinical isolates of Streptococcus pneumoniae at five tertiary-care hospitals in Korea

A 2011-2012 survey of doctors' perceptions of korean guidelines and empirical treatment of community-acquired pneumonia

Background

The causative pathogens of and prevalence of antibiotic resistance in community-acquired pneumonia (CAP) varies across countries. We evaluated the patterns of antibiotic prescriptions for adult CAP patients, and physician satisfaction with the form and content of the 2009 Korean CAP treatment guidelines.

Materials and Methods

We designed an online survey for clinical physicians who treat CAP (infectious disease specialists, pulmonologists, and other physicians). We e-mailed the online survey to physicians and gathered results from December 2011 to January 2012, and then analyzed their responses.

Results

A total of 157 physicians responded to our survey: 61 (38.9%) infectious disease specialists, 33 (21.0%) pulmonologists, and 63 (40.1%) other physicians. Two-thirds (96/157, 61.2%) had positions in tertiary and secondary hospitals; the others (61, 38.8%) worked in primary clinics (hospitals and private clinics). One hundred and eight (68.8%) were aware of the Korean CAP clinical guidelines; of these, 98 (62.4%) applied the guidelines to their practice. Among physicians using them, 86.7% (85/98) reported the guidelines to be most useful for empirical selection of antibiotics, and 75.2% (118/157) said the guidelines were useful and satisfactory. Sixty-eight (43.3%) respondents indicated that they had not used aminoglycosides as an initial empirical CAP treatment, while 51 (32.5%) had combined aminoglycosides with other antibiotics to treat patients with CAP. Seventy-three (46.5%) physicians often combined macrolides with β-lactam antibiotics for empirical treatment of CAP, and 21 (13.4%) reported using macrolide monotherapy (which is not recommended in the 2009 Korean CAP treatment guidelines) for CAP patients. The most commonly used β-lactams were third-generation cephalosporins (72, 45.9%) and ampicillin/sulbactam or amoxicillin/clavulanate (28, 17.8%).

Conclusions

Some physicians remain unaware of the 2009 Korean treatment guidelines for CAP and do not use them in clinical practice. In addition, aminoglycoside combination therapy is frequently and inappropriately used in practice. In some cases, CAP is treated with macrolide monotherapy. Thus, the Korean CAP clinical guidelines must be more aggressively and continuously publicized.

Serotype distribution and antibiotic resistance of 140 pneumococcal isolates from pediatric patients with upper respiratory infections in Beijing, 2010

In the present study, the serotype distribution and antibiotic resistance of S. pneumoniae from pediatric patients with upper respiratory infections in Beijing, 2010 were described. 140 pneumococcal isolates were obtained, and the prevailing five serotypes were 19F (18.6%), 23F (9.3%), 14 (9.3%), 15 (9.3%), and 6A (7.1%). The vaccine coverage of PCV7, PCV10, and PCV13 were 43.6%, 43.6%, and 60.0%, respectively. According to the CLSI 2010 criteria, 99.3% of the S. pneumoniae isolates were susceptible to penicillin. The resistance rates to erythromycin and azithromycin were 96.4% and 97.1%, respectively. Meanwhile, 64.3% (90/140) of all pneumococcal isolates were multidrug-resistant S. pneumoniae (MDRSP). PCV13 covered 68.9% (62/90) of MDRSP strains, whereas it was 47.8% (43/90) for PCV7. ErmB was the dominant macrolide-resistance gene, whereas 30.4% pneumococcal isolates expressed both ermB and mefA. No isolate expressed ermTR. The potential coverage of PCV13 is higher than PCV7 and PCV10 because high rates of serotypes 6A and 19A, and the conjugate vaccines could prevent the spread of MDRSP. S. pneumoniae is still sensitive to penicillin. The resistance rate of S. pneumoniae to macrolides is high and ermB is the dominant macrolide-resistance gene in China, so continued surveillance of the antimicrobial susceptibility of S. pneumoniae may be necessary.

Antimicrobial resistance of Streptococcus pneumoniae in Southeast Austria, 1997-2008

Antibiotic resistance in Streptococcus pneumoniae has increased worldwide but varies within geographical regions. We conducted a retrospective analysis of resistance in S. pneumoniae over a 12-year period to assess local and temporal trends in antibacterial resistance. From 1997 to 2008, a total of 1814 non-duplicate S. pneumoniae isolates were identified at the Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Austria. Antibiotic resistance was determined by the Clinical and Laboratory Standards Institute (CLSI) disk diffusion test. For penicillin, the minimum inhibitory concentration was determined by Etest. Susceptibility was defined according to CLSI interpretive criteria. For penicillin, resistance rates were consistently low at 0.2% over the 12-year study period. An increase in resistance was remarkable for erythromycin (3.5% in 1997; 14.7% in 2008), clindamycin (1.8% in 1997; 10.6% in 2008) and tetracycline (1.8% in 2000; 11.0% in 2008). For trimethoprim/sulfamethoxazole, resistance increased slightly to 9.2% in 2008. Quinolones showed a low resistance rate of 0.2% that persisted over the whole study period. In contrast to previously published national data, resistance to penicillin was observed to remain at a remarkably low and constant level. Although international surveillance programmes have set up sustainable and interlinked data networks, our results suggest that regional surveillance may still be needed as decision support for appropriate empirical antibiotic therapy in the local health setting.

Antimicrobial susceptibility and molecular epidemiology of Streptococcus pneumoniae isolated from Shanghai, China

In this study, the antimicrobial resistance profiles of pneumococci isolated from respiratory specimens of patients from Shanghai, China, in 2004 and 2005 are described. Non-susceptible rates to penicillin and erythromycin among paediatric isolates (n=122) were 63.1% and 94.3%, respectively, whilst those of adult isolates (n=39) were 20.5% and 69.2%, respectively (P<0.0001 and P<0.0002). Nineteen serotypes were identified among 103 tested strains, 73.8% of which belonged to 19F, 14, 23F, 6B and 19A. The erm(B) gene was detected in 51 erythromycin-resistant strains (52.6%), the mef(E) gene in 5 strains (5.2%) and both erm(B) and mef(E) in 41 strains (42.3%). Among 45 sequence types (STs) determined by multilocus sequence typing (MLST) in these 103 isolates, 25 STs were new assignments and 9 STs contained 10 new alleles. On the other hand, 46 (68.7%) of 67 penicillin-non-susceptible S. pneumoniae and 51 (52.6%) of 97 macrolide-resistant S. pneumoniae were characterised as belonging to four international resistant clonal complexes, Taiwan(19F)-14, Spain(23F)-1, Spain(6B)-2 and Taiwan(23F)-15. Our findings indicate that the spread of international resistant clones played a predominant role in the emergence and increase of resistance in Shanghai. Conjugate vaccination may be a promising method to prevent the increase in pneumococcal resistance.