Epidemiological characteristics and antiseptic resistance gene detection of Pseudomonas aeruginosa in children in Suzhou, Jiangsu Province / 中国热带医学

@#Abstract: Objective To investigate the clinical distribution characteristics, drug resistance trends and the carrying of antiseptic resistance gene of Pseudomonas aeruginosa infection in children in Suzhou, in order to provide theoretical basis for the prevention and treatment of Pseudomonas aeruginosa infection in children. Methods The clinical distribution characteristics and drug resistance trends of Pseudomonas aeruginosa isolated from Children's Hospital of Soochow University from 2016 to 2021 were retrospectively analyzed. Forthermore, 101 strains of Pseudomonas aeruginosa were randomly selected to detect the expression of 9 antiseptic resistance genes (qacEΔ1-sul1, qacE, qacEΔ1, qacG, sugE(p), sugE©, emrE, ydgE, ydgF) by polymerase chain reaction. Results Pseudomonas aeruginosa in Soochow University Children's Hospital was mainly isolated from respiratory specimen (47.83%), pus (28.60%) and urine (11.72%); the main departments were intensive care unit(21.45%), general surgery department (15.71%) and respiratory department (12.31%). Patients were mainly aged from 1 month to 1 year old and older than 6 years old (34.31% and 25.38%). The top three drug resistance rates of Pseudomonas aeruginosa were imipenem (11.25%), aztreonam (9.26%) and meropenem (8.02%). Among the 853 strains of Pseudomonas aeruginosa, the drug-resistant strains were mainly from the intensive care unit (58/183), hematology department (33/91), neonatology department (31/96), and there were 57 strains of multi-drug-resistant strains with the detection rate of 6.68%. There were 98 strains (11.49%) of Carbapenem resistant Pseudomonas aeruginosa, and the annual detection rates were 22.06%, 8.40%, 3.60%, 5.67%, 9.85% and 17.20%, respectively. Among the 9 antiseptic resistance genes, the carrying rate of ydgF, sugE© and qacE was 98.02%, 94.06% and 0 respectively. Conclusion Pseudomonas aeruginosa has high resistance to some drugs, so attention should be paid to rational drug use. The carriage rates of of two antiseptic resistance genes exceeded 90%, indicating the need to strengthen research on the mechanism of antiseptic resistance research and rational use of disinfectants

Insight into carbapenem resistance and virulence of Acinetobacter baumannii from a children's medical centre in eastern China.

Carbapenem-resistant Acinetobacter baumannii (CRAB) appeared more frequently in children and caused a great threat to global public health. It is urgent to investigate the carbapenem resistance and virulence of CRAB for clinicians to choose appropriate antibiotics. A retrospective study of 77 nonduplicated CRAB isolates was conducted. The carbapenem resistance and virulence genes were characterized by polymerase chain reaction (PCR) and gel electrophoresis. In the present study, A. baumannii mainly came from the intensive care unit and was mostly isolated from sputum samples. The carbapenem resistant rate of A. baumannii in 2018-2020 increased significantly compared with that in 2016-2017. All isolates had carbapenem resistant genes. They were highly resistant to a variety of antibiotics but were relatively sensitive to fluoroquinolones and tetracyclines. blaVIM and blaOXA-23 were detected in all isolates, whereas blaOXA-51, blaIMP and blaNDM were present in 98.70%, 67.53% and 31.17% of isolates, respectively. Notably, 1 isolate A. baumannii was identified as multidrug-resistant A. baumannii (MDR-AB), and 76 other extensively drug-resistance (XDR) isolates were also detected. Virulence genes were present in 100% of all isolates, including genes in the iron acquisition system (basJ), secretion systems (ompA, plcD), quorum sensing system (abaI) and biofilm formation (csuA). adeH, pgaA, and ptk were present in 98.70%, 98.70% and 94.80% of isolates, respectively. CRAB, which is prevalent in east China, carries a large number of drug resistance and virulence genes. Fluoroquinolones and tetracyclines may be effective antibiotics for the treatment of CRAB infection in children. An in-depth understanding of the resistance and virulence of CRAB is conducive to timely guiding empirical drug use and controlling infection.

Epidemiology and Drug Resistance of Neonatal Bloodstream Infection Pathogens in East China Children's Medical Center From 2016 to 2020.

Introduction: To analyze the pathogen distribution and drug resistance of newborns with bloodstream infection (BSI) to help clinicians choose the appropriate empirical antibiotic therapy for clinical infection control. Methods: A total of 707 neonatal BSI cases were retrospectively analyzed. The bacteria in blood culture-positive samples were cultured, identified, and analyzed for drug sensitivity by routine methods. Statistical software was used to compare and analyze the basic data, pathogenic information, and drug resistance of the main bacteria. Results: The 5-year average positive rate of neonatal blood culture was 2.50%. The number of specimens submitted for inspection in 2020 significantly decreased. The top five infectious pathogens with the highest proportion were coagulase-negative Staphylococcus (67.35%), of which Staphylococcus epidermidis had the highest proportion (31.26%), followed by Escherichia coli (12.87%), Klebsiella pneumoniae (9.05%), Streptococcus agalactiae (8.63%), and Staphylococcus aureus (3.25%). Gram-positive (G+) bacteria were dominant, accounting for 69.45%. The main G+ bacteria had a higher rate of resistance to erythromycin and penicillin G. The main Gram-negative (G-) bacteria had a high resistance rate to a variety of antibacterial drugs, especially cephalosporin antibiotics. The overall resistance of K. pneumoniae was higher than that of E. coli. The top two fungi detected were Candida parapsilosis and Candida albicans. C. parapsilosis did not appear to be resistant to antibiotics, while C. albicans was resistant to multiple antibiotics. The type of microbial infection had a statistically significant difference in the positive rate among the age at delivery and wards (p < 0.05). There were significant differences in the detection of fungi among these groups (p < 0.05). The positive rate of G+ bacteria in the term newborns was significantly higher than that in the preterm newborns (p < 0.05). Preterm newborns are more susceptible to pneumonia. Conclusion: G+ bacteria are the main pathogens of neonatal BSI. Preterm newborns are more likely to be infected with G- bacteria. E. coli and K. pneumoniae are the most common G- bacteria, and both have a high resistance rate to a variety of antibacterial drugs. According to the distribution characteristics and drug resistance, it is very important to select antibiotics reasonably.

Hospitalization for Invasive Pneumococcal Diseases in Young Children before Use of 13-Valent Pneumococcal Conjugate Vaccine, Suzhou, China.

A 13-valent pneumococcal conjugate vaccine against invasive pneumococcal disease (IPD) was introduced in China in April 2017. We describe 105 children <5 years of age who were hospitalized for IPD at Soochow University Affiliated Children's Hospital in Suzhou, China, during January 2010-December 2017. We calculated the incidence of hospitalization for IPD as 14.55/100,000 children in Suzhou. We identified 8 different capsular serotypes: 6B (28.4% of cases), 14 (18.9% of cases), 19A (18.9% of cases), 19F (12.2% of cases), 23F (10.8% of cases), 20 (4.1% of cases), 9V (4.1% of cases), and 15B/C (2.7% of cases). These results provide baseline data of IPD before the introduction of this vaccine in China, enabling researchers to better understand its effects on IPD incidence.

Early clinical predictors for the prognosis of invasive pneumococcal disease.

BACKGROUND: Risk factors related to mortality due to invasive pneumococcal disease (IPD) have been unveiled previously, but early clinical manifestations of IPD based on prognosis remain uncovered. METHODS: The demographic characteristics, clinical features, serotype, antibiotic susceptibility, and outcomes of 97 hospitalized children with laboratory-confirmed IPD from Suzhou, China, were collected and analyzed retrospectively. RESULTS: The median age was 0.69 (0.49-1.55) years in the non-survivor group compared with 2.39 (0.90-3.81) years in the survivor group. The mortality of 97 children with laboratory-confirmed IPD was 17.5% (17/97), and 53.6% of them were aged less than 2 years. Pathogens were mainly from the blood and cerebrospinal fluid, and sepsis was the most frequent type. Statistically significant differences were found in hyperpyrexia, vomiting, anorexia, lethargy, poor perfusion of extremities, Hb level, and Plt count between the nonsurvival and survival groups. Further, the multivariate regression analysis showed that early signs, including hyperpyrexia, vomiting, anorexia, lethargy, and poor perfusion of extremities, were independent risk factors for the in-hospital mortality of children with laboratory-confirmed IPD. The mortality was also associated with antimicrobial sensitivity in pneumococcal isolates. The microbes in 1/17 (5.9%) children who were prescribed an antibiotic showed antimicrobial sensitivity in the nonsurvival group, compared with 21/80 (26.3%) children who survived. The most common serotypes identified were 6B (35.3%, 6/17), 14 (23.5%, 4/17), 19F (23.5%, 4/17), 19A (5.9%, 1/17), 23F (5.9%, 1/17), and 20 (5.9%, 1/17) in the nonsurvival group. The coverage of IPD serotypes of the 7-valent pneumococcal conjugate vaccine (PCV7) was 88.2% (15/17), while that of the 13-valent S. pneumoniae vaccine (PCV13) was 94.1% (16/17) of the coverage in the nonsurvival group. CONCLUSIONS: Recurrent hyperpyrexia, vomiting, anorexia, lethargy, and poor perfusion of extremities in the early stage were independent predictors for the in-hospital mortality of children with laboratory-confirmed IPD. Appropriate use of antibiotics and PCV immunization were the keys to improve the outcome of IPD.

Characteristics of pediatric invasive pneumococcal diseases and the pneumococcal isolates in Suzhou, China before introduction of PCV13.

BACKGROUND: Data on characteristics of invasive pneumococcal diseases (IPD) is limited in China. We aimed to understand the clinical features and explore the molecular characteristics of the pneumococcal isolates in China. METHODS: Since 2010, we prospectively collected the pneumococcal isolates and the IPD patients' demographic and clinical information in Suzhou University Affiliated Children's Hospital (SCH). The antibiotic susceptibility, serotypes, genotypes of Streptococcus pneumoniae strains were identified by E-test, quellung reaction and/or multiplex PCR, and multi-locus sequence typing, respectively. RESULTS: During the period from January 2010 to December 2015, a total of 80 IPD patients were identified. They were diagnosed as meningitis (31.3%), septicemia (27.5%), pneumonia (21.3%) and others (20.0%). About half of them required vancomycin treatment, 42.5% were admitted to ICUs, 36.2% had complications and 6.2% were hospitalized for over 1year. The most common serotypes of the pneumococcal isolates were serotypes 6B and 14, the coverage of PCV13 was 92.5%, and CC236s and CC199s were the most common clone complexes. CONCLUSIONS: Pediatric IPD patients had severe clinical symptoms, demanded intensive treatment, suffered poor prognosis and substantial burden. The pneumococcal isolates' serotype coverage of PCV13 vaccine was high, which leads to implication of PCV vaccine usage among children in China.

[Bacterial pathogenic characteristics of respiratory tract infection in children in Suzhou, China: an analysis of 14,994 cases].

OBJECTIVE: To investigate the bacterial pathogenic characteristics of respiratory tract infection in children. METHODS: The medical data from 14,994 children with respiratory tract infection who were hospitalized in Children's Hospital Affiliated to Soochow University between November 2005 and October 2014 were retrospectively reviewed. RESULTS: Among the 14,994 sputum samples from the children with respiratory tract infection, 3,947 (26.32%) had a positive bacterial culture. The most common bacterial pathogen was Streptococcus pneumonia (12.79%), followed by Haemophilus influenzae (5.02%) and Moraxella catarrhalis (2.91%). The bacterial detection rates differed significantly in different years and seasons and children of different ages (P<0.01). The children who had not taken antibacterial agents before admission had a significantly higher positive bacterial culture rate than those who had taken antibacterial agents (P<0.01). There were significant differences in the bacterial detection rate among the children with different course of disease (<1 month, 1-3 months and >3 months) (P<0.05). The detection rates of Streptococcus pneumonia, Moraxella catarrhalis and Acinetobacter baumannii showed an increased trend with a prolonged disease course (P<0.05). CONCLUSIONS: Streptococcus pneumonia is the most common bacterial pathogen causing respiratory tract infection in children, followed by Haemophilus influenzae and Moraxella catarrhalis. The detection rate of bacterial pathogens varies in different years and seasons and children of different ages. The course of the disease and application of antibacterial agents outside hospital can affect the detection rate of bacterial pathogens in children with respiratory tract infection.

Etiology and epidemiology of children with acute otitis media and spontaneous otorrhea in Suzhou, China.

BACKGROUND: There are scare data about bacterial etiology and the antibiotic susceptibility, serotype distribution and molecular characteristics of pneumococci in children with acute otitis media (AOM) in China. METHODS: A prospective study was conducted in Suzhou University Affiliated Children's Hospital. All children under 18 years of age diagnosed as AOM and with spontaneous otorrhea were offered enrollment, and collection of middle ear fluid was then cultured for bacterial pathogens. The antibiotic susceptibility, serotypes, macrolide resistance genes and sequence types of Streptococcus pneumoniae strains were identified. RESULTS: From January 2011 to December 2013, a total of 229 cases of AOM with spontaneous otorrhea were identified; of these, 159 (69.4%) middle ear fluid specimens were tested positive for bacterial pathogens. The leading cause was S. pneumoniae (47.2%), followed by Staphylococcus aureus (18.8%) and Haemophilus influenzae (7.4%). The antibiotic resistance rates of S. pneumoniae isolates to erythromycin were 99.1%, and the nonsusceptible rate to penicillin was 54.6%. The most common serotypes identified were 19A (45.1%) and 19F (35.4%). The coverage against PCV7 serotypes for this outcome was 56.1% and of PCV13 was 97.6%. The macrolide resistance was mainly mediated by both ermB and mefA/E genes (88.6%). The CC271 was the major clonal complex identified. CONCLUSIONS: S. pneumoniae was a leading cause for AOM in children in Suzhou, China. Antibiotics resistance rates of S. pneumoniae were high and mainly due to the spread of CC271 clonal complex.

Molecular characterization and antimicrobial susceptibility of Streptococcus pneumoniae isolated from children hospitalized with respiratory infections in Suzhou, China.

BACKGROUND: Dissemination of antibiotic resistant clones is recognized as an important factor in the emergence and prevalence of resistance in pneumococcus. This study was undertaken to survey the antimicrobial susceptibility and serotypes distribution of pneumococci and to explore the circulating clones in hospitalized children in Suzhou, China. METHODS: The pneumococci were isolated from the nasopharyngeal aspirates of children less than 5 years of age admitted to Soochow-University-Affiliated-Children's-Hospital with respiratory infections. The capsular serotypes were identified by multiplex polymerase chain reaction (PCR). Antimicrobial susceptibility was tested by E-test. The presence of ermB, mefA/E genes were detected by PCR and the genotypes were explored by Multilocus sequence typing (MLST). RESULTS: From July 2012 to July 2013, a total of 175 pneumococcal isolates were collected and all strains were resistant to erythromycin and clindamycin, about 39.4% strains were non-susceptible to penicillin G. Overall, 174 (99.4%) isolates were resistant to ≥ 3 types of antibiotics. Serotypes 19F (28.1%), 6B (19.7%), 19A (18.0%), and 23F (17.4%) were the most common serotypes in all identified strains. The serotypes coverage of PCV7 and PCV13 were 71.9% and 89.9%, respectively. Four international antibiotic-resistant clones, including Taiwan19F-14 (n = 79), Spain23F-1(n = 25), Taiwan23F-15(n = 7) and Spain6B-2(n = 7), were identified. The Taiwan19F-14 clones have a higher non-susceptibility rate in ß-lactams than other clones and non-clone isolates (p<0.001). In addition, 98.7% Taiwan19F-14 clones were positive of both ermB and mefA/E genes, compare to 33.3% in other clones and non-clone strains. CONCLUSIONS: The spread of international antibiotic-resistant clones, especially Taiwan19F-14 clones, played a predominant role in the dissemination of antimicrobial resistant isolates in Suzhou, China. Considering the high prevalence of PCV7 serotypes and serotype 19A, the introduction of PCV13 may be a promising preventive strategy to control the increasing trend of clonal spread in China.

[Urinary tract infections in the neonatal intensive care unit: clinical analysis of 229 cases].

OBJECTIVE: To study the clinical features, distribution of pathogens, drug susceptibility, and treatment effectiveness in neonates with urinary tract infection (UTI) and admitted to the neonatal intensive care unit (NICU). METHODS: The clinical data of 229 neonates who developed UTI during their stay in the NICU were retrospectively studied. RESULTS: The main clinical manifestations of these children included fever/irregular body temperature, refusing to milk feeding, jaundice, vomiting, diarrhea, poor weight gain, and lethargy. The top three pathogens were Escherichia coli, Enterococcus feces, and Klebsiella pneumoniae. Escherichia coli and Klebsiella pneumoniae were highly resistant to ampicillin and most cephalosporins (≥ 85%), and were highly sensitive to imipenem (100%), meropenem (100%), cefoperazone/sulbactam and piperacillin/tazobactam (>90%). Enterococcus feces were highly resistant to penicillin (100%), rifampicin (84%) and gentamicin (79%), but were sensitive to vancomycin. CONCLUSIONS: The clinical manifestations of neonatal UTI are often atypical and manifested as systemic symptoms. The main pathogenic bacterium is Escherichia coli, and the isolation rate of enterococci can also be high. Most pathogenic bacteria are resistant to penicillin and cephalosporins, and therefore decision-making on drug administration must be based on the results of drug sensitivity tests.

[Comparative studies on the composition and antibiotic-resistance of pathogenic bacteria between children with community-acquired and hospital-acquired pneumonia].

OBJECTIVE: This research was to explore the difference between children with community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP) in the composition and antibiotic-resistance of pathogenic bacteria. METHODS: 241 CAP and 116 HAP with positive sputum culture who were hospitalized from January to December in 2008 in Children's Hospital Affiliated to Suzhou University were selected in this study. The bacteria were identified by traditionally manual method and antibiotic sensitivity tests were performed by K-B method. The chi-square or Fisher's exact test were used for statistical test. RESULTS: In 241 CAP, Streptococcus pneumoniae and haemophilus influenza accounted for (42.2%, 106/251) and (12.4%, 31/251) infection, respectively; however in 116 HAP, Enterobacteriaceae and Non-fermenters accounted for (88.2%, 127/144). In addition, methicillin-resistant Staphylococcus aureus weren't isolated, however, its detection rate was 66.7% in HAP. The drug resistance was 1.5 times higher in HAP than that in CAP for several types of antibiotics, such as ceftazidime (37.5% (6/16) vs 75.6% (31/41)), cefepime (37.5% (6/16) vs 78.0% (32/41)), aztreonam (50.0% (8/16) vs 90.2% (37/41)), cefoperazone/sulbactam (12.5% (2/16) vs 51.2% (21/41)) and piperacillin/tazobactam (12.5% (2/16) vs 56.0% (23/41)). Klebsiella pneumoniae isolated from HAP had higher drug resistance than that isolated from CAP against some antibiotics, for example, gentamicin (0 vs 63.6% (7/11)), SMZ + TMP (20.0% (1/5) vs 63.6% (7/11)) and cefoperazone/sulbactam (0 vs 54.5% (6/11)). We also found Enterobacter cloacae isolated from HAP showed high drug resistance than that isolated from CAP against imipenem (0 vs 46.7% (7/15)), aztreonam (9.1% (1/11) vs 60.0% (9/15)) and cefoperazone (18.2% (2/11) vs 80.0% (12/15)) and Pseudomonas aeruginosa from HAP had higher resistance than that from CAP against gentamicin (0 vs 50.0% (9/18)), amikacin (0 vs 38.9% (7/18)), ceftazidime (0 vs 55.6% (10/18)), cefepime (0 vs 50.0% (9/18)) and cefoperazone (33.3% (2/6) vs 94.4% (17/18)). The detection rates of ESBLs for Escherichia coli were 84.6% (11/13) and 93.3% (14/15) in CAP and HAP, respectively (χ(2) = 0.553, P > 0.05); while for Klebsiella pneumoniae, they were 81.3% (13/16) and 95.1% (39/41), respectively (χ(2) = 2.767, P > 0.05). CONCLUSION: CAP was mainly comprised of Streptococcus pneumoniae and haemophilus influenza; while HAP was mainly comprised of Enterobacteriaceae and Non-fermenters. The drug resistance of gram-negative bacilli was higher in HAP than that in CAP.

[Effects of amino acid substitutions of penicillin-binding proteins 2B, 1A, 2X on minimal inhibitory concentration of beta-lactams against Streptococcus pneumoniae].

OBJECTIVE: To observe the effect of amino acid substitution in conserved sequence of penicillin-binding protein (PBP) 1A, 2B, 2X on antimicrobial activity of beta-lactams against Streptococcus pneumoniae (SP). METHOD: Minimal inhibitory concentration (MIC) of 6 beta-lactams was determined by the E-test in 59 SP strains. The penicillin-binding protein genes pbp1a, 2b, 2x in every SP strain were amplified by nested-polymerase chain reaction (nPCR), then the PCR products were sequenced using automatic genetic analyzer directly. To analyze the amino acid substitutions, the DNA sequences were converted to protein sequences and aligned by Clustalx software. According to amino acid substitution in conserved sequence of PBP2B, 3 phenotypes were observed, including: PBP2B phenotype I (no amino acid substitution); PBP2B phenotype II (Glutamine 432-->Leucine and/or Threonine 445/451-->Alanine/Serine, Glutamic 481-->Glycine, 1 strain had proline insertion between residues 431/432); PBP2B phenotype III (Alanine 624-->Glycine with the addition of phenotype II). According to amino acid substitution in conserved sequence of PBP1A, 3 phenotypes were observed, including: PBP1A phenotype I (no amino acid substitution); PBP1A phenotype II (Threonine 574-->Asparagine, Serine 575-->Threonine, Glutamine 576-->Glycine, Phenylalanine 577-->Tyrosine, 574TSQF-->NTGY); PBP1A III (Threonine 371-->Alanine/Serine, Proline 432-->Threonine with the addition of 574TSQF-->NTGY). According to amino acid substitution in conserved sequence of PBP2X, 4 phenotypes were observed, including: PBP2X phenotype I (no amino acid substitution); PBP2X phenotype II (Histidine 394-->Leucine or Threonine 338-->Alanine); PBP2X phenotype III (Threonine 338-->Alanine, Isoleucine 371-->Threonine, Arginine 384-->Glycine and Leucine 546-->Valine); PBP2X phenotype IV (Methionine 339-->Phenylalanine, Methionine 400-->Threonine with the addition of PBP2X phenotype III). RESULT: Among 59 SP strains antibacterial activities distribution (sensitive strains, intermediate strains and resistant strains) of 6 beta-lactams were penicillin (12, 29, 18); amoxicillin(49, 9, 1); cefuroxime (16, 16, 27); ceftriaxone (47, 1, 11); cefotaxime (47, 3, 9); imipenem (49, 10, 0). beta-lactam antibiotics insensitive strains (intermediate + resistant strain) in PBP2B phenotype III, PBP1A phenotype III, PBP2X phenotype III and IV were significantly increased, the MIC(50) of these strains were significantly higher than that of the others. CONCLUSION: The amino acid substitutions in or vicinal conserved sequence of PBP of SP increase MIC for beta-lactam antibiotics.

[Etiology of pneumonia in hospitalized patients less than 3 years of age].

OBJECTIVE: To understand the etiology of pneumonia in hospitalized patients less than 3 years of age. METHODS: A total of 316 children with pneumonia admitted to the Children's Hospital of Suzhou University in Jiangsu Province from March, 2006 to January, 2007 were enrolled in this study. Sputum samples were obtained by deep nasotracheal aspiration technique for bacterial and viral cultures. RESULTS: Of the 316 samples, specific microbial etiology was obtained in 192 cases (60.8%). Bacterial infection was found in 162 cases (51.3 %), viral infection in 19 cases (6.3%)and compound infection with virus and bacteria in 11 cases (3.5 %). Haemophilus influenzae was the most common agent (46 cases; 14.6%) in bacterial infection, followed by Streptococcus pneumoniae (32 cases; 10.1%). Respiratory syncycial virus (RSV) was the most common agent (12 cases; 4.0%) in viral infection, followed by adenovirus (11 cases; 3.6%). CONCLUSIONS: Bacterial infection was a leading cause of pneumonia in children less than 3 years of age in Suzhou area. Haemophilus influenzae was the most common agent, followed by Streptococcus pneumoniae.

[Study on the molecule epidemiological between resistances of 7 genes interrelated 4 antibiotic to isolated Streptococcus pneumoniae in children].

OBJECTIVE: To investigate the molecule epidemic for 7 genes interrelated penicillin, erythromycin, tetracycline, vancomycin resistance of isolated Streptococcus pneumoniae (SP) in children at Suzhou area. METHODS: (1) Thirty-one pneumococcal isolates were collected from respiratory tract secretions of children with respiratory diseases from Nov 2002 to Apr 2003 at the Children's Hospital of Suzhou University (reference strain ATCC49619). (2) Penicillin susceptibility was determined by E-test, while erythromycin, tetracycline, vancomycin were determined by K-B disk. (3) The detecting of pbp2B, ermA/B, mefA, tetM, vanA, vanB genes by PCR, Sequencing pbp2B genes, Contrasting pbp2B DNA sequences among pneumococcal isolates and SP R6 [penicillin sensitive (www.ncbi.nlm.gov/nucleotide, NC-003098)]. RESULTS: Of thirty-one isolates studied, the results were shown as follows; (1) Penicillin sensibility 38.7% (n = 12), penicillin resistance 61.3% (n = 19), pbp2B mutation 64.5% (n = 20); (2) Erythromycin sensibility 9.7% (n = 3), erythromycin resistance 90.3% (n = 28), ermA/B 71% (n = 22), mefA 32.1% (n = 10), ermA/B + mefA 87.1% (n = 27); (3) Tetracycline sensibility 9.7% (n = 3), tetracycline resistance 90.3% (n = 28), tetM 90.3% (n = 28); (4) Vancomycin sensibility 100% (n = 31), vanA, vanB all 0%. CONCLUSION: Among pneumococcal isolates at our area, penicillin, erythromycin, tetracycline resistance were high, vancomycin was sensitive. Detecting 7 genes interrelated penicillin, erythromycin, tetracycline, vancomycin resistance expressed genotypies for antibiotic resistances in pneumococcal isolates.

[Relation of pbp2B, ermB, ermA/B, mefA genes with resistance to penicillin and erythromycin among Streptococcus pneumoniae isolates from children].

OBJECTIVE: To investigate the relation of pbp2B, ermB, ermA/B and mefA genes to penicillin and erythromycin resistance among isolated Streptococcus pneumoniae (Sp) in children. METHODS: Twenty-six strains of Sp were collected from September 2002 to April 2003 at the Children Hospital of Suzhou University. (1) Twenty-six pneumococcal isolates were obtained from respiratory tract secretions of children with respiratory diseases. (2) Susceptibility of the isolates to penicillin, cefuroxime, ceftriaxone, cefotaxime and erythromycin was determined by E-test. (3) The genes pbp2B, ermB, ermA/B and mefA of the isolates were detected with PCR. (4) The PCR product of pbp2B gene was sequenced. (5) DNA sequences of pbp2B of pneumococcal isolates were compared with those of SpR6 [penicillin sensitive (www.ncbi.nlm.gov/nucleotide, NC-003098)]. RESULTS: Among the 26 isolates studied, pbp2B gene mutation was found in 15(58%) isolates, all were point mutation of A, B, C and D genotypes which were seen in 11(73%), 2(13%), 1(7%) and 1(7%), respectively. The numbers of isolates susceptible to penicillin, cefuroxime, ceftriaxone and cefotaxime were 9(82%), 10(91%), 11(100%) and 11(100%), of 11 non-mutation isolates;numbers of isolates resistant to penicillin, cefuroxime, ceftriaxone, and cefotaxime were 13(87%), 11(73%), 1(7%) and 1(7%) out of 15 isolates with mutation.ErmB, ermA/B, mefA and erm/mef genes were positive in 9(35%), 16(62%), 7(27%) and 21(81%)isolates. MIC of erythromycin was 2 to > 256 mg/L among pneumococcal isolates with erm/mef genes. CONCLUSION: Among antibiotic resistant pneumococcal isolates in the area, the main basis of penicillin resistance was the mutation of pbp2B genes. Genotype A mutation had the highest rate among the isolates with mutation and manifested as resistance to penicillin and cefuroxime. Expression of either all or any of the ermA, ermB and mef genes led to erythromycin resistance. Antibiotics resistant Sp strains in this area are forming a challenge to efficacy of penicillin and erythromycin.

[Study on the molecular epidemiology of beta-lactamase TEM gene in isolated Streptococcus pneumoniae].

OBJECTIVE: To investigate the beta-lactamase TEM gene of isolated Streptococcus pneumoniae (Sp) in Suzhou area. METHODS: Twenty-three strains of Sp were collected from respiratory tract secretions of children with respiratory diseases in Nov 2002 to Apr 2003 at Children's Hospital of Suzhou University (reference strain ATCC49619) to build TEM polymerase chain reaction (PCR) system (reference strain E. coli. 9-j53R1 with TEM gene) TEM gene of 23 strains was detected to comparo the sequences with published TEM gene sequences in GenBank for analyzing TEM gene model. RESULTS: Twenty-one strains had TEM gene with a positive rate of 91.3% (21/23). TEM-129 gene were confirmed from No.17 (SR017, penicillin resistance) TEM sequence. New discovered TEM-129 sequence had a modification (ATG[M]-->ATA[I]) at No.182 code and published (GenBank: www.ncbi.nlm.nih.gov/nucleotide, AY452662). TEM-1 genes were confirmed from other TEM sequences. New discovered TEM-1 gene of isolated Sp had been published (GenBank: www.ncbi.nlm.nih.gov/nucleotide, AY392531) too. CONCLUSION: Isolated Sp had TEM gene (TEM-129, EM-1 genotype) with a positive rate of 91.3%. The result enriched the understanding of isolated Sp with penicillin resistance.