Penicillin-binding proteins (PBPs) are the target of β-lactam antibiotics (the major treatment for Streptococcus pneumoniae infections), and mutations in PBPs are considered as a primary mechanism for the development of β-lactam resistance in S. pneumoniae. This study was conducted to investigate the mutations in the PBPs of clinical S. pneumoniae isolates in Hangzhou, China, in correlation with β-lactam resistance. Results showed that 19F was the predominant serotype (7/27) and 14 of the S. pneumoniae isolates were resistant to both penicillin G and cephalosporin. Genotyping results suggested that β-lactam-resistant isolates primarily exhibited single-site mutations in both the STMK and SRNVP motifs of pbp1a in combination with double-site mutations in the STMK motif of pbp2x, which might be the primary mechanisms underlying the β-lactam resistance of the isolates in this study.
Anti-Bacterial Agents ; pharmacology ; China ; epidemiology ; Drug Resistance, Bacterial ; Humans ; Pneumococcal Infections ; epidemiology ; microbiology ; Streptococcus pneumoniae ; drug effects ; genetics ; beta-Lactams ; pharmacology

In Republic of Korea, a 7-valent pneumococcal conjugated vaccine (PCV7) was licensed for use in infants in 2003, and 13-valent PCV (PCV13) replaced it since 2010. We investigated trends in serotype distribution and antibiotic susceptibility of pneumococcal isolates from adult patients with invasive pneumococcal diseases (IPD). Invasive pneumococcal isolates from adult patients of ≥ 16 years of age were collected from 1997 to 2012. Serotypes of the isolates were determined by the Quellung reaction. Distribution of serotypes was analyzed according to the vaccine types. Antibiotic susceptibility was tested by using E-test strips. A total of 272 invasive pneumococcal isolates were included. The most common serotypes were serotype 19F (8.5%, 23/272), and serotype 3 (8.1%, 22/272), and 24.6% (67/272) of the isolates were of non-vaccine serotypes. Of the 272 isolates, 2.6% (7/272) were penicillin MICs of ≥ 4 µg/mL. The proportion of the PCV13 serotypes decreased from 63.3% (50/79) in 1997-2003 to 48.6% (17/35) in 2011-2012, whereas that of non-vaccine serotypes was 26.6% (21/79) and 25.7% (9/35), respectively, for the same periods. The proportion of the PCV13 serotypes showed a decreasing trend among adult patients with IPD over the study period.
Adolescent ; Adult ; Aged ; Anti-Infective Agents/*pharmacology/therapeutic use ; Ceftriaxone/pharmacology/therapeutic use ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Penicillins/pharmacology/therapeutic use ; Pneumococcal Infections/drug therapy/*microbiology/mortality ; Republic of Korea ; Serogroup ; Serotyping ; Streptococcus pneumoniae/*drug effects/isolation & purification ; Young Adult

OBJECTIVETo study the clinical characteristics of children with meningitis caused by Streptococcus pneumoniae (SP) and the drug sensitivity of SP strains.

METHODSA retrospective analysis was performed on the clinical data of 14 children with SP-infected meningitis between September 2008 and March 2014.

RESULTSOf the 14 cases, 8 cases (57%) aged under 2 years. 13 cases (93%) had fever, 9 cases (64%) had convulsions, and 7 cases (50%) were complicated by septicemia. Eleven cases (79%) had elevated white blood cell (WBC) counts and 10 cases (71%) had elevated serum C-reactive protein (CRP) levels. All 14 children had an elevated nucleated cell count and neutrophils were identified as the predominant cell type. CSF protein>1000 mg/dL was noted in 9 cases (64%). Ten cases (71%) were cured, 2 cases (14.2%) with sequelae and 2 cases (14.2%) died. The drug sensitivity analysis showed that SP had resistance rates of more than 60% to penicillin, erythromycin, clindamycin, tetracycline and sulfa, but it was sensitive to amoxicillin (93%), vancomycin (100%), chloramphenicol (100%) and levofloxacin (100%).

CONCLUSIONSThe clinical characteristics of children with meningitis caused by SP are not different from those with meningitis caused by other bacteria. SP strains are resistant to common antibiotics used in clinical practice, so it is important to monitor the drug resistance of the strains.

Adolescent ; Child ; Child, Preschool ; Drug Resistance, Microbial ; Female ; Humans ; Infant ; Male ; Meningitis, Pneumococcal ; drug therapy ; Retrospective Studies ; Streptococcus pneumoniae ; drug effects

OBJECTIVETo investigate the antimicrobial resistance of invasive and non-invasive Streptococcus pneumoniae (SP) strains in children and to provide a basis for proper use of antimicrobial drugs in the treatment of SP infection.

METHODSSeventy children who were diagnosed with invasive pneumococcal diseases (IPD) between January 2009 and December 2013 were enrolled, and 164 children with lower respiratory tract infection caused by SP were randomly selected as the control group. The samples from sterile sites (blood, cerebrospinal fluid, etc) of children with IPD, as well as the sputum samples of children in the control group, were collected for bacterial culture, and the drug susceptibility tests for isolated SP strains were conducted.

RESULTSA total of 82 invasive strains of SP were isolated from sterile sites of 70 children with IPD; 49 strains (60%) were isolated from blood, and 19 strains (23%) from cerebrospinal fluid. The detection rate of invasive SP strains decreased from 2009 to 2013 (P<0.01). The total detection rates of penicillin-nonsusceptible SP from the invasive and non-invasive strains were 27% and 17% respectively (P>0.05). Among invasive strains, the penicillin-nonsusceptible SP strains had significantly higher rates of insusceptibility to cefotaxime, ceftriaxone, and cefepime than the penicillin-susceptible SP (P<0.01). There were significant differences in the rates of insusceptibility to cefotaxime, ceftriaxone, and meropenem between the sensitive and non-sensitive SP strains (P<0.05). The multidrug resistance rates of the invasive and non-invasive SP strains were 89% and 93% respectively (P>0.05).

CONCLUSIONSInvasive SP can easily invade the blood in children, but the total detection rate has decreased year by year. The results of drug sensitivity tests have guiding significance for proper use of antimicrobial drugs for different SP infections.

Adolescent ; Child ; Child, Preschool ; Drug Resistance, Bacterial ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Streptococcus pneumoniae ; drug effects

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

BACKGROUND: Streptococcus pneumoniae causes life-threatening infections such as meningitis, pneumonia, and febrile bacteremia, particularly in young children. The increasing number of drug-resistant isolates has highlighted the necessity for intervening and controlling disease. To achieve this, information is needed on serotype distribution and patterns of antibiotic resistance in children. METHODS: All cases of invasive pneumococcal disease (IPD) in children aged less than 15 yr recorded at King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia, were reviewed for serotyping and antibiotic susceptibility. Isolates were collected from 78 consecutive patients with IPD between 2009 and 2012. All collected isolates were subjected to serotyping by co-agglutination, sequential multiplex PCR, and single PCR sequetyping as previously described. RESULTS: The most frequently isolated IPD serotypes were 23F, 6B, 19F, 18C, 4, 14, and 19A, which are listed in decreasing order and cover 77% of total isolates. The serotype coverage for the pneumococcal conjugate vaccine (PCV)7, PCV10, and PCV13 was 77%, 81%, and 90%, respectively. Results from sequential multiplex PCR agreed with co-agglutination results. All serotypes could not be correctly identified using single PCR sequetyping. Minimum inhibitory concentration showed that 50 (64%) isolates were susceptible to penicillin, whereas 70 (90%) isolates were susceptible to cefotaxime. CONCLUSIONS: The most common pneumococcal serotypes occur with frequencies similar to those found in countries where the PCV has been introduced. The most common serotypes in this study are included in the PCVs. Addition of 23A and 15 to the vaccine would improve the PCV performance in IPD prevention.
Adolescent ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Cefotaxime/pharmacology ; Child ; Child, Preschool ; DNA, Bacterial/analysis ; Humans ; Infant ; Meningitis/*diagnosis/microbiology ; Microbial Sensitivity Tests ; Multiplex Polymerase Chain Reaction ; Penicillins/pharmacology ; Pneumococcal Vaccines/immunology ; Pneumonia/*diagnosis/microbiology ; Protein Tyrosine Phosphatases/genetics ; Retrospective Studies ; Saudi Arabia ; Serotyping ; Streptococcus pneumoniae/*drug effects/genetics

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

OBJECTIVETo study the clinical characteristics of children who suffered from Streptococcus pneumoniae (SP) septicemia and the drug sensitivity of SP strains.

METHODSA retrospective analysis was performed on the clinical data of 25 children with SP septicemia between January 2009 and December 2012.

RESULTSOf the 25 cases, 16 (64%) were aged under 2 years, 5 (20%) were aged 2-5 years, and 4 (16%) were aged over 5 years. Fourteen cases (56%) were complicated by infection of other organs, and 5 cases (20%) had underlying chronic diseases. Fever was the most common clinical manifestation, and the majority presented with remittent fever. Eight patients with pneumonia or pyothorax had pulmonary symptoms. Five patients with purulent meningitis had neurological symptoms, five cases had hepatosplenomegaly and two cases had septic shock. Nineteen cases (76%, 19/25) had significantly elevated white blood cell (WBC) counts, twenty-one cases (84%, 21/25) had significantly elevated serum C-reactive protein (CRP) levels, and eight cases (50%, 8/16) had significantly elevated serum procalcitonin (PCT) levels. The drug sensitivity analysis showed that invasive SP had high resistance rates to penicillin (96%), clindamycin hydrochloride (88%) and erythromycin (84%), and it was completely sensitive to imipenem, vancomycin, levofloxacin and linezolid. The multi-drug resistance rate of invasive SP was up to 88%. Twenty-three cases (92%) were cured or improved after active treatment.

CONCLUSIONSSP septicemia is commonly seen in children aged under 2 years. The most common clinical manifestation is fever, accompanied by elevated WBC count, CRP level and PCT level, and it is usually complicated by pulmonary or brain infection. Resistance to multiple antibiotics is very common in SP strains, so it is important to properly use antibiotics according to drug sensitivity test results. Patients who receive active treatment have a good clinical outcome.

Anti-Bacterial Agents ; therapeutic use ; Bacteremia ; blood ; complications ; drug therapy ; C-Reactive Protein ; analysis ; Calcitonin ; blood ; Calcitonin Gene-Related Peptide ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Microbial Sensitivity Tests ; Pneumococcal Infections ; blood ; complications ; drug therapy ; Protein Precursors ; blood ; Retrospective Studies ; Streptococcus pneumoniae ; drug effects

BACKGROUNDStreptococcus pneumoniae (S. pneumoniae) is a major causative agent of severe infections, including sepsis, pneumonia, meningitis, and otitis media, and has become a major public health concern. We report the pneumococcal serotype and sequence type (ST) distribution, and antimicrobial resistance of 39 S. pneumoniae strains from seven hospitals in China.

METHODSBlood/cerebrospinal fluid (CSF) and sputum isolates from patients were analyzed to determine S. pneumoniae serotypes by polymerase chain reaction (PCR) and the Neufeld Quellung reaction, the multilocus sequence types (MLST) by PCR and sequencing, and susceptibility to antimicrobial agents by the VITEK Gram Positive Susceptibility Card.

RESULTSA total of 39 isolates were collected including 21 blood/CSF and 18 sputum isolates. Conventional serotyping by the Quellung reaction required 749 reactions. In contrast, PCR based typing needed only 106 PCR reactions. The most frequent serotypes from the blood/CSF isolates were 14 (38.1%), 19A (14.3%), 23F (9.5%), and 18C (9.5%). In the sputum isolates the most frequent serotypes were 19F (33.3%), 23F (16.7%), 19A (11.1%), and 3 (11.1%). The incidence of penicillin resistance in the blood/CSF and sputum isolates was 66.7% and 55.6%, respectively. Statistical analysis showed that patients = 5 years old had a higher resistance to penicillin when they compared with the patients = 65 years old (P = 0.011). Serotypes 14, 19A and 19F were significantly associated with penicillin resistance (P < 0.001). ST320, ST271, and ST876 isolates showed high resistant rates to several antibiotics including penicillin (P = 0.006). All of the isolates of serotype 19A were resistant to both penicillin and erythromycin, and they were all multi-drug resistant (MDR) isolates.

CONCLUSIONSThe specificity and sensitivity of multiplex-PCR are good, and this method represents a substantial savings of time and money, and can be widely used in the laboratory and clinical practice. Data from this research showed an extremely high prevalence of penicillin resistance and an increasing prevalence of multi-drug resistant (MDR) rate in S. pneumoniae. A distinctive emergence of serotype 19A was observed which was also associated with the increasing prevalence of antimicrobial resistance. Therefore, nationwide surveillance of pneumococcal resistance and serotypes is strongly warranted.

Adolescent ; Adult ; Aged ; Child ; Child, Preschool ; Drug Resistance, Multiple, Bacterial ; Humans ; Infant ; Microbial Sensitivity Tests ; Middle Aged ; Molecular Typing ; methods ; Multilocus Sequence Typing ; methods ; Pneumococcal Infections ; microbiology ; Serotyping ; Streptococcus pneumoniae ; classification ; drug effects

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