ABSTRACT
Objective To analyze the clinical and molecular features of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in neonates and to investigate their antibiotic resistance profiles.Methods A total of 35 invasive CA-MRSA strains were collected from six hospitals in 2014.Multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing and spa typing were used to analyze these isolated CA-MRSA strains.In vitro antibiotic susceptibilities of those strains to 15 antibiotics were analyzed by using agar dilution method.Results Up to 88.6% patients were late-onset infection and septicemia (24, 68.5%) was the most common infection among the 35 cases.A total of 16 patients (45.7%) suffered from complications.Caesarean section and premature birth were risk factors for invasive CA-MRSA infection.ST59-MRSA-SCCmecⅣa-t437 (14, 40%) was the most predominant CA-MRSA clone, followed by ST59-MRSA-SCCmecⅤ-t437 (13, 37.1%).The incidence of severe complications caused by ST59-MRSA-SCCmecⅤ-t437 was higher than that caused by ST59-MRSA-SCCmecⅣa-t437 (P<0.05).Up to 85.7% of the isolated CA-MRSA strains were multidrug-resistant strains.Conclusion This study shows that neonatal invasive CA-MRSA infections mainly result in septicemia and are often accompanied by complications and involve multiple organs.Multidrug-resistant CA-MRSA strains are prevalent in neonates.ST59-MRSA-SCCmecⅣa-t437 is the predominant clone causing neonatal invasive CA-MRSA infection.
ABSTRACT
Objective To investigate the antimicrobial resistance and genotype distribution of staphylococcal cassette chromosome mec (SCCmec) of staphylococcus aureus (S.aureus) isolated from children hospitalized at Pediatric People's Hospital of Zhongjiang County.Methods Seventy-seven strains of S.aureus were collected by nasopharyngeal swabs at the Pediatric Department of People's Hospital of Zhongjiang County from January to December 2015.Methicillin-resistant staphylococcus aureus (MRSA) and methicillin-susceptible staphylococcus aureus (MSSA) were identified by cefoxitin disc diffusion and detection of mecA method.The minimum inhibitory concentrations (MIC) of antibiotics were determined by E-test method.SCCmec typing on MRSA strains was performed by using multiplex PCR.Results MRSA accounted for 54.5％ (42 strains) strains of 77 strains.All MRSA strains were resistant to Penicillin,and the rates of antibiotic resistance to Cefuroxime,Ceftriaxone,Erythromycin were 78.6％,95.2％ and 97.6％,respectively.The rates of antibiotic resistance of 35 MSSA to Penicillin and Erythromycin were 97.1％ and 62.9％,and they were also sensitive to other antibiotics.In 42 strains of MRSA,SCCmec type Ⅳa was the predominant type (27 strains,64.3 ％),which was followed by type Ⅳ g and Ⅴ (each 5 strains,11.9％),type Ⅳ c and Ⅳh (each 1strain,2.4％).Non-susceptibility rate of SCCmec Ⅳ to cefuroxime was significantly higher than that of other SCCmec types (P ＜ 0.05).Conclusions All strains from children hospitalized in People's Hospital of Zhongjiang County are often resistant to Penicillin and Erythromycin.The proportion of MRSA isolated from hospitalized children was high.SCCmec type Ⅳa is the main genotype of MRSA.
ABSTRACT
10.3969/j.issn.1000-3606.2013.06.005
ABSTRACT
Objective To detect the antibodies of streptococcal C5a peptidase from group B streptococcus(SCPB)in neonates,demonstrate the existence of SCPB antibody in pregnant women after natural group B streptococcus(GBS)infection,and provide clinical evidence for prevention of GBS infection. Methods Sera were collected from 107 neonates(80 term infants and 27 premature infant)between February 2007 and December 2007. The antibodies of SCPB were detected using ELISA method,and cultures of GBS were done simultaneously. Results 21(19.6%)newborns were found to be SCPB antibody positive(including 20 term infants and 1 premature infant),the difference of positive ratio between term and premature infant was significant(25% and 3.7%,respectively). Conclusions This study indicated that pregnant women could produce SCPB antibody by immune response,and transmitted it to the infants through the placenta. Further study is needed to clarify the effect of SCPB antibody in expectant mother and newborn with GBS infection.
ABSTRACT
Objective To investigate the distribution of the emm types and superantigens of group A streptococcal ( GAS) isolated from Chinese children. Methods Totally 222 GAS isolates collected from five Children's Hospitals of China during 2005～2006 were studied, emm types were performed by PCR and sequencing. The eight superan-tigen (SAg) genes (speA, speC, speH, speI, speG, speJ, ssa and SMEZ) were checked by PCR. Results Nine emm types were identified, of which emml2 (55. 86% ) and emml (39. 64% ) were the most prevalent types. The GAS isolates carried six or more SAg genes take 78. 39% of all the isolates in this study. The SAg gene profiles were closely associated with the emm type. Conclusion The emm type of S. pyogenes isolated from Chinese chil-dren was quite wide-spreading and SAg genes appeared to be associated with the emm type so its expression is po-tential in vaccine development.
ABSTRACT
Objective To obtain better insights into transmission dynamics of macrolide resistance genes between human and animal Enterococcus strains.Methods The antimicrobial susceptibility to 8 anti-bioties of 52 Enterococci isolated from animal and 55 Enterococci isolated from human was determined.PCR was used to detect the macrolide resistance genes ermB and mefA,tetracycline resistance genes tetM,and the integrase gene int of Tnl545 of the total 107 strains.Forty-nine ermB positive strains were chosen to be se-quenced.Filter mating experiments were taken.Results The resistance rate to erythromycin were 89.09% and 80.77%for isolates from human and animal:and resistance rate to tetracycline were 80.00%and 67.3l%for isolates from human and animal.respectively.All isolated Enterococci strains were found sensi-tive to vancomycin ermB was detected in 61.82% human Enterococci and 53.85% porcine ones.Identical er-mB gene sequences were found in animal and human Enterococci.Transfer of the ermB gene from porcine E.faecalis to human E.feacalis was successful.and the transfer frequency is 1.2×10-5.Conclusion En-terococci have a high resistance rate to erythromycin and some other antibio tics,especially in pediatric iso-lates:but still very sensitive to glycopeptide.ermB was the predominant genes for macrolide and tetracy-cline.Identical ermB gene sequences were present in animal and human Enterococci and that transfer of the ermB gene from porcine E.faecalis to human E.faecalis and vice versa is possible.but probably occurs at a low frequency.
ABSTRACT
Objective To determine the drug-resistance rate of Enterococci isolated from patients of 5 padiatric hospitals located at different areas in China,and to investigate the distribution of resistance genes ermB,mefA,tetM and the integrase gene intTn of Tn1545 in Enterococci.Methods The antimicrobial susceptibility to 8 antibiotics of 2 216 Enteroeocei isolates was determined.PCR was used to detect the macrolide resistance genes ermB and mefA,tetracycline resistance genes tetM,and the integrase gene int-Tn of Tn1545.Results The resistance rates to erythromycin,ampicillin,gentamicin and teicoplanin were 86.5%,48.0%,60.5% and 0.7%,respectively.All isolated Enterococci straim were found sensitive to vancomycin.Of the detected 225 strains,70.7% of the 225 detected strains carried ermB gene while 75.1% of them carried tetracycline resistance gene tetM:only one strain had mefA.The presence of ermB gene in erythromycin MIC＞256 mg/L straim group(95.7%)strains was higher than those in erythromycin MIC＜256 mg/L group(2.5%).The int-Tn gene was detected in 40.9%(92/225)of the 225 test strains.The presence of ermB gene in int-Tn positive group strains was higher(84.8%)than those in int-Tn negative strains group(60.9%).So did the tetM in int-Tn positive group(83.7%)compared with those in int-Tn negative group(70.0%).Conclusions Enterococci sbowed a high resistance rate to the antibiotics we monitored,especially to erythromycin;but still very senstive to glycopeptide antibiotics. Resistance to macrolide in Enterococci collected from clinical in five Children's Hospital was generally mediated by methylation of 23S rRNA via ermB methylase. Enterococci resistance to tetracycline was predominantly due to ribosomal protection encoded by tetM. There was a strong relationship of the ermB and tetM genes with Tn1545-related elements.
ABSTRACT
Objective To study the system of streptococcal C5a peptidase (ScpB) and the specif-ic antibody levels in serum, lung, vagina and recta after subcutaneous and intranasal immunization with dif-ferent doses of C5a peptide. Methods Recombinant protein C5a peptide was expressed in E. coli strain BL21 and purified by affinity chromatography. The expressed product was identified by SDS-PAGE and pep-tide mass fingerprinting (PMF). BALB/c mice were subcutaneously and intranasally injected with different doses of ScpB. Antibody titer was tested by ELISA. Opsonophagocytosis assay was used to test the function of antibody. Results ScpB protein was successfully expressed and purified. The probability based mouse score of ScpB was 175 by PMF analysis. ELISA data showed that both subcutaneous and intranasal immtmi-zation could elicit significantly higher levels of IgG in immunized mice serum than that of control group (P ＜0.01), 30 μg group waa better than 5 μg and 10 μg group. Intranasal immunization could elicit higher lev-els of IgA in lung, vagina and rectum (P ＜0.001) while system immunization could not. Opsenophagocyto-sis tests indicated that anti-serum of ScpB had opsenophagocytic activity than that of control (P ＜ 0. 05).Conclusion The results demonstrated that intranasal immunization with ScpB could induce significantly higher levels of lgG and IgA, and its anti-serum had better opsenic activity.
ABSTRACT
Objective To develop a molecular method to type coagulase-negative staphylococci(CNS) using 16S～23S internal transcribed spacer-PCR(ITS-PCR)Methods ITS-PCR was performed to identify six control strains and a collection of 171 clinical strains, identified as CNS by AutoScan-4 System The API Staph system also tested the discrepant strainsResults A total of 11 CNS species from control strains and clinical ones confirmed by the API Staph system were resolved by their unique ITS-PCR patterns These results constructed the primary database of CNS in the laboratory They were obtained with Staphylococcusepidermidis, Shaemolyticus, Shominis, Ssaprophyticus, Sxylosus, Swarneri, Scapitis, Scohhni subspurealyticum,S sciuri, Sauricular, Ssimulans Only S sciuri showed intraspecific polymorphism on its ITS-PCR pattern 9357%(160/171) clinical isolates can be identified by this ITS-PCR data base and the accuracy is 9375%(150/160) The coincidence of the API Staph system and ITS-PCR was better than that of AutoScan-4 system results There is at lest 936%(16/171) CNS results from AutoScan-4 system are falseConclusion ITS-PCR is verified as a valuable, easy to perform, rapid, high reliable and low cost molecular typing method for coagulase negative staphylococci
ABSTRACT
<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>A 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.</p><p><b>RESULTS</b>Prevalence 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%).</p><p><b>CONCLUSION</b>The 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.</p>
Subject(s)
Child, Preschool , Humans , Infant , Infant, Newborn , Anti-Bacterial Agents , Pharmacology , China , Epidemiology , Drug Resistance, Bacterial , Drug Resistance, Multiple , Prevalence , Respiratory Tract Infections , Microbiology , Streptococcus pneumoniaeABSTRACT
Objective To indicate the restriction profiles of pbps in Streptococcus pneumoniae(S.pneumoniae), and relationship between pbps profiles and the penicillin MIC.Methods The E-test MIC method was used to determinate penicillin susceptibility of 132 S.pneumoniae strains consisting of 69 penicillin susceptible S.pneumoniae (PSSP) strains and 63 nonsusceptible S.pneumoniae (PNSP) strains. Furthermore, we compared these strains by detecting restriction fragment length polymorphism (RFLP) of the PBPs genes pbp1a, pbp2b and pbp2x.Results The RFLP results showed that 9 genotypes were founded for pbp1a, in which 2 were detected from PSSP and some PNSP strains. The other 7 ones were founded mainly in the PNSP with penicillin MIC≥0.25 ?g/ml. Ten genotypes were founded for pbp2b, in which 3 were detected from PSSP and some PNSP strains. The other 7 ones, similar with pbp1a, were founded mainly in the PNSP with penicillin MIC≥0.25 ?g/ml. Thirty-one restrictive patterns were founded for pbp2x. Seventeen patternss from them were detected in PSSP, and 13 ones were founded only in PSSP. The other 14 patterns all were covered PNSP strains. A total of 47 patterns were found according to the three pbps types. Twenty-three patterns from them were detected in PSSP, and 17 ones were founded only in PSSP. The other 24 patterns all were detected in PNSP.Conclusions Results of the study are consistent with the concept that mutations in PBP1a, PBP2b and PBP2x play an important role in the development of resistance to ?-lactam antibiotics by S.pneumoniae. In the meantime, the profiles of pbps can predict penicillin susceptibility.
ABSTRACT
Objective To distinguish BRO ?-lactamase by use of restriction endonuclease analysis and investigate antibacterial agents resistance of Moraxella catarrhalis(M. Catarrhalis) with different BRO ?-lactamases .Methods Nasopharyngeal swabs of children with respiratory tract infections from the outpatient department of Beijing Children's Hospital were cultured for isolating M.Catarrhalis. BSAC(british society for antimicrobial chemotherapy) agar diffusion test was used to determine antibacterial agents resistance of M.Catarrhalis.Nitrocefin disk was used to detect ?-lactamase. Restriction endonuclease analysis was used to distinguish BRO ?-lactamases . Antibacterial agents resistance of M. Catarrhalis with different bro genes was compared.Results (1)95.0% of the 80 strains were beta-lactamase positive. MIC 90 of ampicillin was 32 ?g/ml and MIC 90 of cefuroxime,cefaclor and cefotaxime were 4 ?g/ml,8?g/ml and 1?g/ml respectively,MIC 90 of tetracycline was 16?g/ml. Among the antibacterial agents,ciprofloxacin was the most sensintive agent.(2)Among 80 strains,6(7.5%) Strains were bro negative,55(68.8%) were bro-1 positive,19(23.8%)were bro-2 positive。Except 2 strains,the results of ?-lactamases were same as the results of nitrocefin disk and restriction endonuclease analysis.(3)Compared with bro-2 positive strains,the MIC value of ampicillin and cefaclor for bro-1 positive strains were higher.Conclusions Antibacterial agents resistance of M. Catarrhalis to ampicillin was sierous in China. It should be strengthened to monitor antibacterial agents resistance of M.Catarrhalis. Restriction endonuclease analysis can play an important role on characterizing bro genes,evaluating antibacterial agents resistance of Moraxella Catarrhalis to ?-lactam and investigating molecular epideminology