Bacteria ; drug effects ; isolation & purification ; Drug Resistance ; Escherichia coli ; drug effects ; Female ; Haemophilus influenzae ; drug effects ; Humans ; Klebsiella pneumoniae ; drug effects ; Male ; Microbial Sensitivity Tests ; Respiratory Tract Infections ; microbiology ; Staphylococcus aureus ; drug effects ; Streptococcus pneumoniae ; drug effects

BACKGROUND: With the emergence of antimicrobial resistance among Streptococcus pneumoniae, a more accurate and automated antimicrobial susceptibility testing method is essential. We evaluated the BD Phoenix Automated Microbiology System (Becton Dickinson Diagnostic Systems, USA) SMIC/ID-2 panel for antimicrobial susceptibility testing of S. pneumoniae. METHODS: A total of 113 clinical strains of S. pneumoniae (88 penicillin susceptible strains, 8 intermediate strains, and 17 resistant strains by 2008 CLSI criteria) were tested. Minimum inhibitory concentrations (MICs) for penicillin, cefotaxime, clindamycin, erythromycin, levofloxacin, trimethoprim/ sulfamethoxazole, tetracycline, and vancomycin were determined by Etest (AB Biodisk, Sweden) and Phoenix System. The results obtained by Phoenix system were compared to those obtained by Etest. RESULTS: The overall essential agreement of MICs (within one dilution of MICs) defined by the Phoenix and Etest was 92.3%. Neither very major errors nor major errors were produced, and minor errors were 6.5%. Minor errors were frequently observed in susceptibility testings for penicillin (22.1%), cefotaxime (12.4%), and trimethoprim/sulfamethoxazole (11.5%). CONCLUSIONS: The Phoenix SMIC/ID-2 panel provided a simple and rapid susceptibility testing for S. pneumoniae, and the results were in a good agreement with those of Etest. The Phoenix system appears to be an effective automated system in clinical microbiology laboratories.
Anti-Bacterial Agents/pharmacology ; Bacterial Typing Techniques/instrumentation/methods ; Drug Resistance, Bacterial ; Microbial Sensitivity Tests/*methods ; Reagent Kits, Diagnostic ; Streptococcus pneumoniae/*drug effects/growth & development/isolation & purification

OBJECTIVETo investigate the nasal carriage of antibiotic-resistant pneumococci in children of < 5 years old in the following four cities, Beijing, Shanghai, Guangzhou and Xi'an.

METHODSA total of 647 pneumococci strains were isolated and detected. Minimal inhibition concentrations (MICs) of antibiotics were determined by E-test. Disk diffusion test was used for the measurement of antimicrobial susceptibility.

RESULTSPrevalence of penicillin non-susceptible Streptococcus pneumoniae in the four cities was 41%, with Guangzhou (60.8%) ranking first, followed by Xi'an (45%), Shanghai (37%) and Beijing (25.9%). The majority of penicillin non-susceptibility isolates (23.9% - 53.8%) had a low level of resistance (MIC 0.64 - 1.5 microg/ml). The most sensitive antimicrobials in terms of percentage of susceptible organisms were amoxicillin-clavulanic acid (99.4%), followed by ceftriaxone (92.1%); cefurxime and cefaclor were slightly more sensitive than penicillin with susceptibility of 74.8% and 77.9%. Erythromycin, tetracycline and TMP-SMZ were highly resistant (83.6%, 82.1% and 76.2% respectively). Among erythromycin resistant isolates, 100% were resistant to azithromycin, 98.6% to clarithromycin, 97.2% to roxithromycin and spiramycin, and 96.6% to clindamycin. 97.2% (141/145) were typical of the macrolides-lincosamides-streptogramons B (MLSB) resistance phenotype, and 2.8% (4/145) were M phenotype. The group of PRSP was with significantly higher rates of non-susceptibility for ceftriaxone (18.4%), cefurxime (58.6%), cefaclor (53.4%), compared with the group of PEN-S (0.5%, 1.8% and 0.2%, respectively) and the rate of multi-drug resistance in the isolates of PRSP group (92.9%) was significantly higher than that of PEN-S group (59.2%).

CONCLUSIONThe rates of penicillin and multi-drug resistance among isolates of pneumococci carried nasally in are high children and the high prevalence of multi-drug resistance in the Chinese population may be becoming one of the most serious problems in this century.

Anti-Bacterial Agents ; pharmacology ; Child, Preschool ; China ; epidemiology ; Drug Resistance, Bacterial ; Drug Resistance, Multiple ; Humans ; Infant ; Infant, Newborn ; Prevalence ; Respiratory Tract Infections ; microbiology ; Streptococcus pneumoniae ; drug effects ; isolation & purification

BACKGROUNDDespite the prevalence of Streptococcus pneumoniae serotype 19A, the molecular characteristics of this serotype are yet to be fully elucidated. The aim of this study was therefore to determine the homology of the serotype 19A in China.

METHODSPulsed-field gel electrophoresis and multilocus sequence typing were done to these forty-nine serotype 19A isolates to investigate the relationship between the strains prevalent in Beijing and other regions.

RESULTSFrom 1997 to 2006, the percentage of serotype 19A isolates increased. The susceptibility rate to penicillin and amoxicillin decreased and the resistance rate to cefuroxime increased. ST320 was the most prevalent ST, followed by ST3546. There were six new STs identified in our study. The serotype 19A strains were classified into six different pulsed-field gel electrophoresis (PFGE) patterns. ST320, which was associated with two different PFGE patterns (A and D), accounted for 32 isolates, and ST3546, which was associated with two PFGE patterns (B and E), accounted for eight isolates.

CONCLUSIONSFrom 2003 onwards, ST320 was the most common ST and the rate of resistance to cefuroxime increased significantly. Further long-term surveys of Streptococcus pneumoniae serotype 19A are required to monitor ST prevalence and antimicrobial resistance in this important human pathogen.

Child, Preschool ; China ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Humans ; Infant ; Infant, Newborn ; Molecular Epidemiology ; Pneumococcal Infections ; drug therapy ; microbiology ; Serotyping ; Streptococcus pneumoniae ; classification ; drug effects ; genetics ; isolation & purification ; Time Factors

OBJECTIVE: To investigate the pathogenic bacteria distribution and drug susceptibility in children with acute otitis media (AOM) in different age and different season in the Pearl River Delta region. METHOD: Four hundred and forty-two children diagnosed as AOM were divided into three groups by age factor and four groups by season factor. Midge ear pus collecting and culturing were used for bacteria and antimicrobial susceptibility test. RESULT: (1) Strains of bacteria were isolated from 356 children with the positive rate of 80.5%. Streptococcus pneumoniae (39.2%), staphylococcus aureus (25.9%) and haemophilus influenzae (7.4%) were the most frequently isolated pathogens. (2) Streptococcus pneumoniae was the main pathogenic bacteria in 0-1 year group and > 1-3 years group (P < 0.05), staphylococcus aureus was the most frequently isolated pathogen in >3 years group (P < 0.05); (3) In the season groups, the number of children with AOM decreased significantly in July-September group. There was no significant difference of streptococcus pneumoniae distribution among the four groups (P > 0.05). Staphylococcus aureus was the main pathogen in January-March group (P < 0.05); (4) Drug sensitivity shown that linezolid and ofloxacin were most sensitive to streptococcus pneumoniae and staphylococcus aureus, and macrolides had a good therapy effect to haemophilus influenzae. CONCLUSION The pathogens distribution and drug susceptibility in children with AOM were varies in different age and different season. As a result, a treatment should be done based on the climate, environment, and pathogens distribution of a region.
Adolescent ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Haemophilus influenzae ; drug effects ; isolation & purification ; Humans ; Infant ; Male ; Microbial Sensitivity Tests ; Otitis Media ; drug therapy ; epidemiology ; microbiology ; Seasons ; Staphylococcus aureus ; drug effects ; isolation & purification ; Streptococcus pneumoniae ; drug effects ; isolation & purification

BACKGROUND: The present analysis focuses on phenotypic and genotypic characterizations of efflux-mediated erythromycin resistance in Streptococcus pneumoniae due to an increase in macrolide resistance in S. pneumoniae worldwide. METHODS: We investigated the prevalence of efflux-mediated erythromycin resistance and its relevant genetic elements from 186 specimens of S. pneumonia isolated from clinical and normal flora from Tehran, Iran. The presence of erythromycin resistance genes was tested by PCR with two sets of primers, specific for erm(B) and mef(A/E), and their genetic elements with tetM, xis, and int genes. Isolates were typed with the BOX PCR method and tested for resistance to six antibiotics. RESULTS: Antibiotic susceptibility tests revealed that 100% and 47% isolates were resistant to tetracycline and erythromycin, respectively. The erythromycin and clindamycin double-disc diffusion test for macrolide-lincosamide-streptograminB (MLSB) resistance phenotype showed 74 (84%) isolates with the constitutive MLSB phenotype and the remaining with the M phenotype. BOX PCR demonstrated the presence of 7 types in pneumococci with the M phenotype. Fourteen (16%) isolates with the M phenotype harbored mef(A/E), tetM, xis, and int genes. CONCLUSIONS: The present results suggest dissemination of polyclonal groups of S. pneumoniae with the M phenotype carrying resistance genes attributed to transposon 2009.
Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; DNA, Bacterial/metabolism ; Drug Resistance, Multiple, Bacterial/*genetics ; Erythromycin/*pharmacology ; Genotype ; Humans ; Microbial Sensitivity Tests ; Phenotype ; Pneumococcal Infections/microbiology/pathology ; Polymerase Chain Reaction ; Streptococcus pneumoniae/*drug effects/*genetics/isolation & purification ; Tetracycline/pharmacology

We investigated serotype distribution and antimicrobial resistance of pneumococcal carriage isolates from children after optional immunization with the 7-valent pneumococcal conjugate vaccine (PCV7) in Korea. From June 2009 to June 2010, 205 (16.5%) pneumococcal isolates were obtained from 1,243 nasopharyngeal aspirates of infants and children at Seoul National University Children's Hospital, Korea. Serotype was determined by Quellung reaction and antibiotic susceptibility was tested by E-test. The results were compared to previous studies done in the pre-PCV7 period. In this study, the most common serotypes were 6A (15.3%), 19A (14.7%), 19F (10.2%), 35B (7.3%), and 6D (5.6%). The proportion of PCV7 serotypes decreased from 61.9% to 23.8% (P < 0.001). The overall penicillin nonsusceptibility rate increased from 83.5% to 95.4% (P = 0.001). This study demonstrates the impact of optional PCV7 vaccination in Korea; the proportion of all PCV7 serotypes except 19F decreased while antimicrobial resistant serotypes 6A and 19A further increased.
Anti-Bacterial Agents/pharmacology ; Child, Preschool ; Drug Resistance, Bacterial/drug effects ; Humans ; Infant ; Microbial Sensitivity Tests ; Nasopharynx/*microbiology ; Pneumococcal Infections/immunology/prevention & control ; Republic of Korea ; Serotyping ; Streptococcus pneumoniae/classification/*isolation & purification ; Vaccination ; Vaccines, Conjugate/*immunology

OBJECTIVETo investigate nasopharyngeal carriage rate, antimicrobial resistance and serotype distribution of Streptococcus pneumoniae among children with upper respiratory infection.

METHODSNasopharygeal swabs were collected from children with upper respiratory infection visiting the outpatient department of Beijing Children′s Hospital between March 2013 and February 2014. The antibiotic susceptibility was tested by Etest method, and the serotype was determined by Quellung reaction.

RESULTSThe nasopharyngeal carriage rate for Streptococcus pneumoniae was 23.8% (699/2 941). One hundred isolates were randomly chosen for antimicrobial susceptiblity test and serotyping. Up to 98.0% isolates were susceptible to parenteral penicillin. The susceptible rate against oral penicillin, however, was 33.0%. The non-susceptible rate to erythromycin and azithromycin was 97.0%. The multi-drug resistance rate was up to 86.0%. The common serotypes were 6A(12.0%), 19F(12.0%), 6B(10.0%), 23F(9.0%) and 14(8.0%). The coverage rates of 7-, 10- and 13-valent pneumococcal conjugate vaccine were 41.0%, 42.0% and 59.0% respectively.

CONCLUSIONSAbout 25% of children with upper respiratory infection are nasopharyngeal colonized by Streptococcus pneumoniae. The isolates show a high antimicrobial resistance. The 13-valent pneumococcal conjugate vaccine covers about 60.0% of the isolates.

Adolescent ; Carrier State ; epidemiology ; microbiology ; Child ; Child, Preschool ; Drug Resistance, Bacterial ; Female ; Humans ; Infant ; Male ; Nasopharynx ; microbiology ; Pneumococcal Vaccines ; immunology ; Respiratory Tract Infections ; microbiology ; Serotyping ; Streptococcus pneumoniae ; classification ; drug effects ; isolation & purification

BACKGROUNDErythromycin-resistant Streptococcus pneumoniae isolates that causing invasive pneumococcal diseases (IPD) in Chinese children remain uncharacterized. This study aims to identify the resistance genes associated with erythromycin resistance and to determine the genetic relationships of IPD isolates in Chinese children.

METHODSA total of 171 S. pneumoniae strains were isolated from 11 medical centers in China from 2006 to 2008. All the isolates were characterized via serotyping and antibiotic susceptibility determination. The erythromycin-resistant isolates were further characterized via ermB and mefA gene detection, multi-locus sequence typing analysis, and pulsed-field gel electrophoresis.

RESULTSA total of 164 (95.9%) isolates showed resistance to erythromycin, of which 162 strains with high high-level resistance (MIC ≥ 256 µg/ml). A total of 104 (63.4%) isolates carry the ermB gene alone, whereas 59 (36.0%) harbor both ermB and mefA genes. Of the 59 strains, 54 were of serotypes 19A and 19F and were identified as highly clonal and related to the Taiwan(19F)-14 clone.

CONCLUSIONSThe erythromycin resistance rate in IPD isolates is significantly high and is predominantly mediated by the ermB gene. Isolates that carry both ermB and mefA genes are predominantly of serotypes 19A and 19F.

Adolescent ; Anti-Bacterial Agents ; pharmacology ; Child ; Child, Preschool ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Erythromycin ; pharmacology ; Humans ; Infant ; Multilocus Sequence Typing ; Pneumococcal Infections ; microbiology ; Serotyping ; Streptococcus pneumoniae ; classification ; drug effects ; genetics ; isolation & purification

OBJECTIVETo investigate the situation of antibiotic resistance of Streptococcus pneumoniae (Sp) and Hemophilus influenzae (Hi) clinical isolates from children in Guangzhou area.

METHODSThe authors cultured, isolated and identified the Sp and Hi strains from nasopharyngeal secretion of patients who visited Guangzhou Children's Hospital for upper respiratory tract infection between 2003 and 2004. K-B disc diffusion and E-test for antibiotic susceptibility were performed for these clinical isolates.

RESULTSTotally 172 and 484 strains of Sp and Hi were respectively isolated from nasopharyngeal secretions in the hospital. For Sp strains, the rates of resistance to penicillin, amoxicillin/clavulanic acid, ceftriaxone, cefuroxime, cefaclor, erythromycin, tetracycline, chloramphenicol, sulfamethoxazole/trimethoprim (SMZ/TMP), clindamycin and ofloxacin were 32.0%, 11.1%, 32.6%, 18.1%, 39.5%, 82.6%, 78.5%, 24.4%, 87.2%, 69.2% and 3.1%, respectively. The penicillin non-susceptible Sp (PNSSP) isolates showed higher rates of resistance to other antimicrobial agents such as other beta-lactam antimicrobial agents, erythromycin, and SMZ/TMP than those of penicillin susceptible Sp (PSSP) isolates. More than 90% of PNSSP were multidrug resistant strains. The average rate of beta-lactamase production among 484 strains of Hi was 29.5% (143/484). For Hi isolates, the rates of resistance to ampicillin, amoxicillin/clavulanic acid, ceftriaxone, cefuroxime, cefaclor, SMZ/TMP, tetracycline, chloramphenicol, azithromycin, and ofloxacin were 40.1%, 3.4%, 4.1%, 1.9%, 5.6%, 56.2%, 52.1%, 17.4%, 2.1%, and 0.6%, respectively.

CONCLUSIONThe antimicrobials resistant Sp and Hi isolated from children with respiratory tract infection in the area have become a severe problem. The rate of resistance to penicillin of Sp had been decreased compared with the last three years, but the rate of resistance to ceftriaxone of Sp increased, and the multidrug resistance rates of PNSSP was rather high. PNSSP was characterized by a multidrug-resistance to erythromycin, tetracycline and SMZ/TMP. beta-lactamase production and ampicillin resistance among the Hi isolates from children in the area had increased generally during the period 2003 - 2004. The Hi isolates were more susceptible to the second and the third generation cephalosporins, amoxicillin/clavulanic acid and azithromycin.

Anti-Bacterial Agents ; pharmacology ; Child, Preschool ; China ; Drug Resistance, Bacterial ; Female ; Haemophilus Infections ; drug therapy ; microbiology ; Haemophilus influenzae ; drug effects ; isolation & purification ; Humans ; Infant ; Infant, Newborn ; Male ; Microbial Sensitivity Tests ; Nasopharynx ; microbiology ; Pneumonia, Pneumococcal ; drug therapy ; microbiology ; Respiratory Tract Infections ; drug therapy ; microbiology ; Streptococcus pneumoniae ; drug effects ; isolation & purification