Microbial detection and analysis of a foodborne disease caused by Staphylococcus aureus infection / 中国基层医药

Objective:To identify the cause of a suspected foodborne disease caused by bacterial food poisoning using multiple detection methods.Methods:At 9:35 a.m. on August 9, 2022, a suspected foodborne disease incident was handled by the Hefei Center for Disease Control and Prevention. The preliminary laboratory test results showed that the foodborne disease was caused by Staphylococcus aureus infection. Sixteen strains of Staphylococcus aureus were isolated, cultured, and identified using real-time fluorescent polymerase chain reaction. At the same time, the 16 strains of Staphylococcus aureus isolated from different sources were analyzed by pulsed-field gel electrophoresis to determine the correlation between strains. Results:The distribution of 16 strains of Staphylococcus aureus enterotoxins isolated was that the anal swab and chopping board (inner) smear samples from a salesperson surnamed Li showed SEB type, and the remaining 14 strains all carried type A, C, and E enterotoxin genes simultaneously. Pulsed-field gel electrophoresis typing results showed that there were two types of strains; except the anal swab and chopping board (inner) smear samples from the salesperson surnamed Li, the other 14 strains were all of the same type, with a similarity of 100%. The similarity between the anal swab and the chopping board (inner) smear samples from the salesperson surnamed Li was 80.65%, and the similarity with another type was 59.26%. This result was consistent with the detection results of Staphylococcus aureus enterotoxins. Conclusion:The foodborne disease in this case was caused by mixed contamination of two or three different sources of Staphylococcus aureus with enterotoxins.

Molecular characteristics of Streptococcus suis type 2 from humans in Zhejiang Province / 中华传染病杂志

Objective:To determine the molecular characteristics of Streptococcus suis type 2 (SS2) in Zhejiang Province. Methods:Twenty-nine SS2 sporadic human isolates in Zhejiang Province from Januery 2005 to July 2021 were genotyped by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and minimum core genome (MCG) sequence typing.Results:Among 29 strains, 10 PFGE patterns and three main clusters were obtained by PFGE. Twenty-one (72.41%) of the strains were divided into two main branch groups and the remaining eight (27.59%) showed genetic diversity with the similarity ranging from 49.7% to 94.7%. Three sequence types were obtained from 29 strains by MLST, including ST7 (86.21%(25/29)), ST1 (10.34%(3/29)) and ST25 (3.45%(1/29)). In addition, three genotypes were obtained from 29 strains by MCG, including genotype E (41.38%(12/29)), genotype group 1 (55.17%(16/29)) and genotype group 4 (3.45%(1/29)).Conclusions:Two large clonal groups of highly pathogenic strains of SS2 have been prevalent in Zhejiang Province. A few strains display genetic diversity, indicating genetic variation may exist during transmission.

Distribución y caracterización fenotípica y genotípica de Listeria monocytogenes en aislamientos de alimentos, Colombia, 2010-2018 / Distribution and phenotypic and genotypic characterization of Listeria monocytogenes isolated from food, Colombia, 2010-2018

Resumen | Introducción. Listeria monocytogenes es un patógeno transmitido por alimentos que causa infecciones en humanos, entre ellas, meningitis, meningoencefalitis y septicemias, así como abortos. Con la tipificación serológica se han identificado 13 serotipos, siendo el 4b el causante de la mayoría de los brotes en el mundo. Objetivo. Determinar la frecuencia y la distribución de los serotipos y subtipos moleculares de L. monocytogenes aislados de alimentos en Colombia entre el 2010 y el 2018. Materiales y métodos. Se hizo un estudio descriptivo y retrospectivo a partir del análisis de 2.420 aislamientos que fueron identificados como L. monocytogenes y otras especies, por medio de pruebas bioquímicas, serológicas y de subtipificación molecular mediante electroforesis en gel de campo pulsado (PFGE). Resultados. De los 2.420 aislamientos recibidos, 2.326 fueron confirmados como L. monocytogenes. Los serotipos encontrados fueron: 4b (52%), 4d-4e (14,5%), 1/2a (11%), 1/2c (9,4%), 1/2b (9 %), y 3a, 3b, 3c, 4c, 4d, 4e y 7 (menos de 2%). Procedían de Bogotá (43%), Antioquia (25%), Valle (10%), Nariño (9%) y otros departamentos (7%). La caracterización genotípica agrupó los aislamientos evaluados en 167 patrones de PFGE; los perfiles más frecuentes se presentaron en productos lácteos, cárnicos y alimentos preparados. Conclusión. El 96,1 % de los aislamientos correspondieron a L. monocytogenes, con una buena concordancia entre el aislamiento y la identificación; el serotipo 4b, extremadamente virulento, fue el más frecuente. El análisis molecular evidenció la posible diseminación y permanencia en el tiempo de varios serotipos, lo que resalta la importancia de incluir este patógeno en los programas de vigilancia epidemiológica en alimentos.

Abstract | Introduction: Listeria monocytogenes is a food-borne pathogen that may cause infections in humans such as meningitis, meningoencephalitis, and septicemia, as well as abortions. By serological typing 13 serotypes have been identified of which 4b is responsible for most of the outbreaks in the world. Objective: To determine the frequency and distribution of serotypes and molecular subtypes of L. monocytogenes isolated in Colombia from food from 2010 to 2018. Materials and methods: We conducted a retrospective and descriptive study based on the analysis of 2,420 isolates confirmed as L. monocytogenes and other species using biochemical and serological tests, and pulsed-field gel electrophoresis (PFGE) for molecular subtyping. Results: Of the 2,420 isolates received, 2,326 were confirmed as L. monocytogenes. The serotypes found were 4b (52%), 4d-4e (14.5%), 1/2a (11%), 1/2c (9.4%), 1/2b (9%), and 3a, 3b, 3c, 4c, 4d, 4e and 7 (less than 2%). The isolates came from Bogotá (43%), Antioquia (25%), Valle (10%), Nariño (9%), and other departments (7%). The genotypic characterization grouped the isolates in 167 PFGE patterns. The most frequent patterns were identified in various dairy and meat products, and in prepared foods. Conclusion: A 96.1% of the isolates corresponded to L. monocytogenes showing good agreement between isolates and identification. Serotype 4b, highly virulent, was the most frequent. The molecular analysis showed the possible dissemination and permanence over time of several serotypes, which highlights the importance of including this pathogen in epidemiological food surveillance programs.

Streptococcus pneumoniae serotype 3 genotypes in invasive isolates from Colombia / Genotipos del serotipo 3 de Streptococcus pneumoniae en aislamientos invasivos en Colombia

Abstract | Introduction: Streptococcus pneumoniae serotype 3 is an important cause of pneumonia, bacteremia, and meningitis. Objective: To establish the circulating genotypes of S. pneumoniae serotype 3 isolates recovered from the invasive disease between 1994 to 2015 in Colombia. Materials and methods: Of the 365 S. pneumoniae serotype 3 isolates recovered through the laboratory national surveillance program, 117 isolates were analyzed. Pulsed-field gel electrophoresis was used for genotyping, and multilocus sequence typing was determined in representative isolates. Results: The frequency of this serotype increased from 2.7% between 1994 and 1998 to 9.1% between 2011 and 2015 (p=0.000); 91.7% of the isolates showed a genetic similarity greater than 77% and were related to the Netherlands3-31(PMEN31) clone CC180. Several subtypes were identified, two of which showed antimicrobial resistance. Conclusion: In Colombia, the pneumococcal population of the capsular type 3 shows a continuous and homogeneous circulation relating to the clonal group ST-180.

Resumen | Introducción. El serotipo 3 de Streptococcus pneumoniae es una causa importante de neumonía, bacteriemia y meningitis. Objetivo. Establecer los genotipos circulantes de aislamientos del serotipo 3 de S. pneumoniae recuperados de muestras de enfermedad invasiva de 1994 a 2015 en Colombia. Materiales y métodos. Se analizaron 117 de los 365 aislamientos del serotipo 3 de S. pneumoniae recuperados del programa nacional de vigilancia por el laboratorio. El genotipo se estableció con electroforesis en gel de campo pulsado y la tipificación se llevó a cabo mediante secuenciación multilocus en aislamientos representativos. Resultados. La frecuencia de este serotipo aumentó de 2,7 % entre 1994 y 1998 a 9,1 % entre 2011 y 2015 (p=0,000). El 91,7 % de los aislamientos evidenció una similitud genética superior al 77 % y se relacionó con el clon CC180 de Netherlands3-31 (PMEN31). Se identificaron varios subtipos, dos de los cuales mostraron resistencia a los antimicrobianos. Conclusión. En Colombia, la población neumocócica del tipo capsular 3 tiene una circulación continua y homogénea relacionada con el grupo clonal ST-180.

Molecular epidemiological analysis of carbapenem-resistant Klebsiella pneumonia in China from 2009 to 2016 / 中华检验医学杂志

Objective@#The study aimed to investigate the drug sensitivity and molecular epidemiological analysis of carbapenem-resistant Klebsiella pneumoniae in China from 2009 to 2016.@*Methods@#For Klebsiella pneumoniae collected from China Antimicrobial Resistance Surveillance Trial (CARST) from 2009 to 2016, those resist to ertapenem were screened out as the carbapenem-resistant Klebsiella pneumoniae(CRKP). Antibiotic susceptibilities of 14 antibacterial agents to the bacteria were assessed by minimum inhibitory concentration (MIC) using two-fold agar dilution test which was recommended by the Clinical and Laboratory Standard Institute (CLSI). Carbapenemases were filtered out by the modified carbapenem inactivation method(mCIM) and EDTA-modified carbapenem inactivation method(eCIM) test, PCR was used to screen for the presence of carbapenemase genes or not. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to analyze the homology of these isolates.@*Results@#A total of 193 CRKP were screened out in the 2 502 Klebsiella pneumoniae isolates. The resistance rates of 193 CRKP isolates to colistinE (4.0%), tigecycline (7.2%), fosfomycin (25.4%) and amikacin (38.3%) were less than 40%. However, the resistance rates to the other 9 antimicrobial agents were higher than 65%. There were 143 carbapenemase gene detected in 193 CRKP, of which blaKPC-288(45.6%) and blaNDM-140(20.7%) were the most common. In the 126 isolates of Klebsiella pneumoniae producing KPC-2 and NDM-1 carbapenemases, a total of 33 ST-types were detected, mainly was ST11 (59.5%). All ST11 strains produce KPC-2 carbapenemase. A total of 111 clones were obtained from PFGE fingerprints, there were 12 clones in which the same clone strains were equal or greater than 2.@*Conclusion@#The resistance rate of Klebsiella pneumoniae to carbapenems has been rising from 2009 to 2016, and clinicians should take reasonable measures to strengthen the monitoring of resistance to CRKP and control its spread across the country.

Characteristics and drug resistance of non-O157 Shiga toxin-producing E. coli in animal feces, from Shandong Province / 中华预防医学杂志

Objective@#To understand the infection status, characteristics and drug resistance of non-O157 Shiga toxin-producing E. coli (STEC) in animal feces in Shandong Province.@*Methods@#From 2015 to 2016, convient sampling method was used to collect 1 022 fresh feces of animals in Weishan county and Laizhou city, and 24 non-O157 STEC were isolated. The serotypes of non-O157 STEC strains were confirmed through serum agglutination test. The susceptibility was explored through the antimicrobial sensitivity experiments. ESBLs activity was confirmed by double-disc diffusion. PCR method was used to detect the resistance genes. PFGE typing was operated to assess the relatedness and variability of the strains. The multi-locus sequence typing (MLST) was adopted to get the allelic profile and ST sequence of strains. Analysis was made on the evolutionary relationship between different ST groups was made through CLC Sequence Viewer and Counting Express.@*Results@#A total of 24 non-O157 STEC were isolated from animal feces. 23 strains were from pig feces, and 1 strain was from cow feces, and the serotypes were more dispersed. All of the 24 strains carried stx2 genes. The highest resistance rate was sulfamethoxazole(22 strains), the mount of cotrimoxazole and nalidixic acid was 18 strains, chloramphenicol was 13 strains, tetracycline was 19, and there was a phenomenon of multiple drug resistance. The drug resistance spectrum was sulfamethoxazole tetracycline-compound novammin-naphthidine-chloramphenicol. All strains were sensitive to cefepime and imipenem. The ESBLs confirmatory test showed that 4 strains of non O157 STEC produced beta lactamase. PCR detected 7 resistance genes, and 4 tetracycline resistance genes (Tet A, Tet B, tetC and tetD) were detected. The beta lactamase resistance genes (blaSHV-1, bla CTX-M, bla TEM) were all negative. 24 strains were divided into 15 PFGE types, and their clustering results were more dispersed and no dominant PFGE type. There were 11 kinds of MLST types, most of them are ST540 and ST5133 types, each of which was 4 strains, and clustered into 1 MLST genomes.@*Conclusion@#The serotypes of non-O157 STEC in animal feces O157 STEC were dispersed, and the resistant rate to common antibiotic was high. MLST typing results presents obvious polymorphism. Surveillance and manage ment of these strains should be strengthened.

Molecular characterization of non-vaccine Streptococcus pneumoniae serotypes 11A, 15 B/C and 23A recovered from invasive isolates in Colombia / Caracterización molecular de los serotipos no vacunales 11A, 15 B/C y 23A de Streptococcus pneumoniae recuperados de aislamientos invasivos en Colombia

Resumen Introduction: A total of 192 invasive Streptococcus pneumoniae isolates, from serotypes 11A, 15B/C and 23A (not included in the conjugated vaccines), were collected in Colombia between 1994 and 2014 as part of the activities of the Network surveillance system for the causative agents of pneumonia and meningitis (SIREVA II). Objective: To determine the molecular characteristics ofinvasive S. pneumoniaeisolates from serotypes 11A, 15B/C and 23A in Colombia from 1994 to 2014. Materials and methods: The molecular characterization of the isolates was carried out through Pulse-Field Gel Electrophoresis (PFGE) and Multilocus Sequence Typing (MLST). Results: Serotype 11A showed one clonal group represented by ST62. Serotype 15B/C was composed of three groups associated with Netherlands15B-37 ST199 (28.75%), ST8495 (18.75%), and SLV (Single-Locus Variant) of ST193 (21.25%). Isolates from serotype 23A were gathered in three clonal groups, with70.21% closely related toST42, 17.02% to Colombia23F-ST338, and6.38% to Netherlands15B-37 ST199. Conclusion: Clones Colombia23F-ST338 andNetherlands15B-ST199 covered more serotypes than those previously found by other authors, including serotype 23A. These analyses reveal the importance of capsular switching in the spreading of successful clones among non-vaccine serotypes causing invasive pneumococcal disease.

Abstract Introducción. En Colombia se recolectaron 192 aislamientos invasivos de Streptococcus pneumoniae de los serotipos 11A, 15B/C y 23A (no incluidos en las vacunas conjugadas) entre 1994 y 2014, como parte de las actividades del Sistema de Redes de Vigilancia de los Agentes Responsables de Neumonías y MeningitisBacterianas (SIREVA II). Objetivo. Determinar las características moleculares de aislamientosinvasivos de los serotipos11A, 15B/C y 23A de S. pneumoniae recolectados en Colombia entre 1994 y 2014. Materiales y métodos. La caracterización molecular de los aislamientos se hizo medianteelectroforesis en gel de campo pulsado (Pulse-Field Gel Electrophoresis, PFGE) y por tipificación de secuencias multilocus (Multilocus Sequence Typing, MLST). Resultados. El serotipo 11A mostró un grupo clonal representadopor el ST62, en tanto que el serotipo15B/C se distribuyó en tres grupos asociados conlos clones Netherlands15B-37 ST199 (28,75 %), ST8495 (18,75 %) y SLV (variante en un solo locus) de ST193 (21,25 %). Los aislamientos con serotipo 23A se agruparon en tres gruposclonales; 70,21 % de ellos estaban estrechamente relacionadoscon elST42, 17,02 % con elColombia23F-ST338, y 6,38 % con el Netherlands15B-37 ST199. Conclusión. Los clones Colombia23F-ST338 y Netherlands15B-ST199 encontrados en este estudio abarcaronmás serotipos de los reportados previamente por otros autores, incluido el serotipo23A. Estos análisis revelan laimportancia de la conmutación(switching) capsular en la expansión de clones exitosos entre los serotipos no vacunales como causa de enfermedad invasiva neumocócica.

Characteristics of molecular typing and drug resistance of 67 Salmonella paratyphi A isolated in Zhengzhou from 2013 to 2015 / 中华预防医学杂志

Objective@#To investigate the antimicrobial resistance and pulsed field gel electrophoresis (PFGE) patterns of S.paratyphi A strains in Zhengzhou city isolated from sentinel hospitals in 2013-2015.@*Methods@#According to Salmonella molecular typing and K-B drug susceptibility testing method published by international PulseNet bacterial infectious disease monitoring network and USA Clinical and Laboratory Standards Institute (CLSI2015), we analyzed drug sensitivity and PFGE molecular characteristics of 67 S.paratyphi A strains(11 strains in 2013, 7 strains in 2014, 49 strains in 2015) isolated from blood and stool samples in two sentinel hospitals of fever with rash syndrome surveillance system established in Zhengzhou city in 2013-2015.@*Results@#The results showed 67 strains of S.paratyphi A had different levels of resistance to 13 kinds of antibiotics, 65 strains were multi-drug resistant strains (97.0%), 5 isolates were resistant to 2-3 kinds of antibiotics (7.5%), 41 isolates were resistant to 5-8 kinds of antibiotics (61.2%),11 isolates were resistant to 9-10 kinds of antibiotics(16.4%),8 isolates were resistant to 11-12 kinds of antibiotics(11.9%). 67 strains of S.paratyphi A were divided into 10 molecular patterns(PTYA1-PTYA10) by digestion with XbaⅠ restriction endonuclease and pulsed field gel electrophoresis, each pattern contains 1-48 strains with similarity ranged from 94.31%-100%. PTYA3 contained 48 strains, which was predominant band type; PTYA1, 9 contained 6 strains; PTYA 2, 4, 5, 6, 7, 8, 10 contained 1 strains among them.@*Conclusion@#The status of drug resistance of clinical isolates of S.paratyphi A in Zhengzhou city was rather serious, PFGE patterns showed diversity and dominant characteristics. The PFGE patterns of partial strains and its corresponding anti-drug spectrum have certain relevance and cluster relationship.

Detection of virulence gene and molecular typing of Shigella boydii isolated from clinical sources / 天津医药

Objective To understand genetic distribution, drug resistance, molecular typing and the epidemiological relativeness between strains of the Shigella boydii virulence. Methods Nine Shigella boydii strains were isolated form stool samples of patients with diarrhea from the Enteric Disease Clinic of the Second Hospital of Tianjin Medical University in June-October 2015. The strains were identified by biochemical test and serum agglutination test. Antibiotics susceptibility test was carried out using the Kirby-Bauer method. Polymerase chain reaction was used for detecting virulence genes. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) technique were used to determine the epidemiological relationship between nine Shigella boydii strains. Results There were three subtypes in nine isolated Shigella boydii samples, including one, three and five isolates inⅠ,Ⅱ,Ⅳsubtypes respectively. All of the 9 isolates were multi-drug resistant. The resistant rate of these strains for ampicillin was 100%(9/9), and then the resistant rates of these strains for ceftazidime, streptomycin, gentamicin, trimethoprim/sulfamethoxazole, cefotaxime, ceftriaxone, norfloxacin and levofloxacin were 1/9, 4/9, 4/9, 4/9, 5/9, 5/9, 6/9, 6/9 and 6/9, respectively. All of these strains were sensitive to amikacin, cefperazone-sulbactam and imipenem. The ipaH was carried by all the testing strains, and none of the strains carried the sen, set1A, set1B, ial, virA, icsA and SigA. The detective rates of pic, sepA and sat were 4/9, 5/9 and 7/9 strains, respectively. Nine shigella boydii strains were divided into 8 PFGE types. The similarity between the spectrums of PFGE was 63.21%-100%. Multilocus sequence typing showed that six isolates were belonged to ST648, two isolates were ST131 and one isolate was ST10. Conclusion Nine isolates of Shigella boydii (divided into three subtyping) isolated from our hospital are multi-drug resistant and they have distant relationships, belonging to the dissemination of case.

Molecular characteristics of Streptococcus pneumoniae in Shanghai, China / 中华检验医学杂志

Objective Toinvestigate the molecular characteristics including antibiotic resistance,strain type,serotype,virulence,biofilm formation of Streptococcus pneumoniae isolated from Shanghai adult patients.Methods A total of 37 non-repetitive S.pneumoniae isolates causing community acquired and hospital acquired infections of adults were collected from Shanghai Huashan Hospital from January 2011 to December 2013.The inhibitory zone diameter or minimum inhibitory concentrations (MICs) of 9 antimicrobial agents (penicillin,vancomycin,erythromycin,clindamycin,levofloxacin,cefprozi,ceftriaxone,cefotaxime and linezolid) were determined by Kirby-bauer (K-B) method or Etest method;Serotypes were tested by polymerase chain reaction (PCR) and S.pneumoniae antisera agglutination;Genomic characteristics of different serotype strains were determined by pulsed field gel electrophoresis (PFGE)method;Multilocus sequence types (MLST) was used for strain type;Semi quantitative biofilm formation test was used for the biological membrane formation.Ten main pneumococcal virulence genes (cbpA,pspA,cps2A,lytA,nana,pavA,piaA,ply,psaA and spxB) were detected by PCR and gel electrophoresis.Statistical analysis was performed using Stata software and association statistics were tested using Fisher's exact test.Results The most frequent serotypes were 19F (13.5％),23 F (13.5％),14 (10.8％),19A (10.8％).The penicillin resistance rate was 64.9％.Serotypes 19 F,19A and 23 F were significantly associated with penicillin resistance (x2 =5.89,P =0.015) and the isolates belonged to these serotypes were all multi-drug resistant (MDR).ST81 and ST271 showed high resistance rates to several antibiotics including penicillin (x2 =4.57,P =0.033).Biofilm formation was significantly associated with serotypes 19A (x2 =5.55,P =0.018) and strain type ST320 (x2 =4.33,P =0.037),but not associated with penicillin resistance (x2 =0.16,P =0.686).Virulence gene lytA,pavA,ply,psaA,spxB were found in all isolates.Conclusions Penicillin resistance rate of S.pneumoniae in adult is rising.Specific serotype,epidemic clone and antibiotic resistance are closely related,and can provide the basis for the infection control.The virulence factors such as PspA will be the new targets for vaccine development to reduce S.pneumoniae infection in the future.

Recurrent Pseudomonas aeruginosa Infection in Chronic Lung Diseases: Relapse or Reinfection? / 결핵및호흡기질환

BACKGROUND: Pseudomonas aeruginosa infection is particularly associated with progressive and ultimately chronic recurrent respiratory infections in chronic obstructive pulmonary disease, bronchiectasis, chronic destroyed lung disease, and cystic fibrosis. Its treatment is also very complex because of drug resistance and recurrence. METHODS: Forty eight cultures from 18 patients with recurrent P. aeruginosa pneumonia from 1998 to 2002 were included in this study. Two or more pairs of sputum cultures were performed during 2 or more different periods of recurrences. The comparison of strains was made according to the phenotypic patterns of antibiotic resistance and chromosomal fingerprinting by pulsed field gel electrophoresis (PFGE) using the genomic DNA of P. aeruginosa from the sputum culture. RESULTS: Phenotypic patterns of antibiotic resistance of P. aeruginosa were not correlated with their prior antibiotic exposition. Fifteen of 18 patients (83.3%) had recurrent P. aeruginosa pneumonia caused by the strains with same PFGE pattern. CONCLUSION: These data suggest that the most of the recurrent P. aeruginosa infections in chronic lung disease occurred due to the relapse of prior infections. Further investigations should be performed for assessing the molecular mechanisms of the persistent colonization and for determining how to eradicate clonal persistence of P. aeruginosa.

Epidemiological survey of Campylobacter infection associated with acute bacterial infectious children diarrhea in Shanghai / 中华检验医学杂志

Objective To assess the prevalence of Campylobacter in the children with acute bacterial diarrhea in Shanghai.Methods Epidemiological survey.Totally 6 641 children with acute bacterial infectious diarrhea from outpatients and inpatients in Children′s Hospital of Fudan University were submitted to the investigation during January 2011 to December 2012.The Campylobacter was isolated from stool samples collected from subjects in micro aerobic environment and identified by both multi-PCR and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry ( MALDI-TOF MS ) .Antimicrobial susceptibility tests were assayed by disk-diffusion method according to EUCAST standard.The isolates molecular typing was done by PFGE.SPSS16.0 was used to analyze the results.Results A total number of 6 641 subjects were enrolled, among them, 305 patients were infected with Campylobacter.The prevalence rate was 4.6%(305/6 641).Among the infected patients, 240 patients were infected with Campylobacter jejuni and 65 patients were infected with Campylobacter coli, the infectious rates of these two pathogenic bacteria were 3.6%and 1.0%, respectively.The peak infectious rate in patients older than 1 year of age was 6.2%(209/3 385) which was higher than that in children under 1 year of age (2.9%, 96/3 256),χ2 =35.98,P<0.001.The infectious rate in winter and spring (6.8%, 138/2 040) was higher than that in the other seasons ( 3.6%, 167/4 601 ) ,χ2 =28.59, P <0.001.Antimicrobial susceptibility test results showed that 91.5%( 279/305 ) isolates were resistant to ciprofloxacin and 11.8%( 36/305 ) isolates were resistant to erythromycin.A total of 9 genotypes of Campylobacter were found by PFGE cluster analysis.The similarity were ranged from 65.1%-100.0%for type A, 67.6%-100.0%for type B, 61.7%-100.0%for type C, 59.0%-100.0%for type D, 71.4%for type F, 80.0%for type H, 54.4%-90.9%for type I, and only one strain was classified as type E and G.Conclusions Campylobacter is a major pathogenic bacteria associated with acute bacterial infectious diarrhea in children especially in children older than 1 year of age in Shanghai.The prevalent pattern of this pathogen was sporadic and the sharp peak was in winter and spring.The isolates are highly resistant to ciprofloxacin but still sensitive to erythromycin.

Molecular characterization of Streptococcus pneumoniae serotype 1 invasive isolates in Colombia / Caracterización molecular de cepas invasoras de Streptococcus pneumoniae serotipo 1 aisladas en Colombia

OBJECTIVE: To determine the genetic relationship between Streptococcus pneumoniae serotype 1 Colombian isolates recovered from invasive disease between 1994 and 2011 and recognized serotype 1 international clones. METHODS: A total of 135 S. pneumoniae serotype 1 isolates with epidemiological and antimicrobial susceptibility data (Clinical and Laboratory Standards Institute, 2012) were studied. The genetic relationship with recognized international clones was established by pulsed-field gel electrophoresis (PFGE) with SmaI restriction enzyme. Multilocus sequence typing (MLST) was standardized to determine the sequence type (ST) in seven isolates representing different clonal groups. Control and reference strain R6, and clones Sweden¹ ST217, Sweden¹ ST304, Sweden¹ ST306, and USA¹ ST615, were used. RESULTS: PFGE revealed that 89.7% of the isolates were associated with Sweden¹ ST306, 3.7% were associated with Sweden¹ ST304, and 6.6% were not clonally related. Using MLST, ST306 was confirmed in six isolates and ST304 in one. CONCLUSIONS: In contrast to Brazil and the United States, where clones Sweden¹ ST304 and ST227 prevail, invasive disease caused by S. pneumoniae serotype 1 in Colombia is principally associated with the dispersion of isolates related to clone Sweden¹ ST306.

OBJETIVO: Determinar la relación genética entre las cepas de Streptococcus pneumoniae serotipo 1 aisladas en Colombia en casos de enfermedad invasora entre 1994 y 2011 y los clones internacionales reconocidos del serotipo 1. MÉTODOS: Se estudiaron un total de 135 cepas de S. pneumoniae serotipo 1 de las que se tenían datos epidemiológicos y de sensibilidad a los antimicrobianos (Clinical and Laboratory Standards Institute, 2012). Se estableció su relación genética con los clones internacionales reconocidos mediante electroforesis en gel de campo pulsátil (PFGE) utilizando la enzima de restricción SmaI. Se estandarizó la tipificación de secuencias mulitlocus (MLST) para determinar el tipo de secuencia (ST) en siete cepas que representaban diferentes grupos clonales. Se utilizaron la cepa de control y referencia R6 y los clones Sweden¹ ST217, Sweden¹ ST304, Sweden¹ ST306, y USA¹ ST615. RESULTADOS: La PFGE reveló que 89,7% de las cepas se asociaban con Sweden¹ ST306, 3,7% con Sweden¹ ST304, y 6,6% no mostraron relación clonal. Mediante MLST, se confirmó la relación con ST306 en seis cepas y con ST304 en una. CONCLUSIONES: A diferencia de Brasil y Estados Unidos, donde prevalecen los clones Sweden¹ ST304 y ST227, la enfermedad invasora causada por S. pneumoniae serotipo 1 en Colombia se asocia principalmente con la dispersión de cepas relacionadas con el clon Sweden¹ ST306.

The Application of DiversiLab System in Klebsiella pneumoniae Genotyping / 天津医药

Objective To analyze Klebsiella pneumoniae by DiversiLab system, providing scientific evidence for the control of nosocomial infection. Methods Eight strains of non-duplicated clinical Klebsiella pneumoniae isolated from the surgical ward in a hospital in 2010 were typed by rep-PCR-based DiversiLab system. The results were compared with those of pulsed-field gel electrophoresis (PFGE). Results Antimicrobial susceptibility test showed that 7 clinical strains were the same sensitivity to 11 antimicrobial agents, except the strain K8-02. And these 7 clinical strains were all multi-drug re-sistant. The result of PFGE showed that 7 strains were the same pattern. The result of DiversiLab also showed that 7 strains were the same pattern, and the strain K8-02 was another pattern. Conclusion DiversiLab system is simple, quick, good re-peatability and accurate, which is a kind of standardization and automation system. DiversiLab system and PFGE method could get the same result.

Ciprofloxacin non-susceptible Streptococcus pyogenes due to mutations in parC gene and its homology analysis / 中华检验医学杂志

Objective To investigate the resistant mechanism of Streptococcus pyogenes to ciprofloxacin and its homology.Methods Forty-eight isolates of Streptococcus pyogenes were collected from patients diagnosed with scarflet fever in districts of Beijing in March,2012 and MIC to ciprofloxacin and other 7 common antibiotics in clinic were detected by using blood M-H agar dilution method.Thirteen isolates,which have MICs≥4 mg/L against ciprofloxacin,were detected for mutations of Fluoroquinolone resistance genes gyrA,gyrB,parC,parE.At the same time,4 isolates,with MIC ≤ 0.25 mg/L against ciprofloxacin,were used for comparison.Homology analysis of 17 isolates from different areas of Beijing was performed by using the method of pulsed field gel electrophoresis.Results Sensitive rates of Streptococcus pyogenes to levofloxacin,ampicillin and penicillin were all 100％.The resistance rates to tetracycline,erythromycin and clindamycin were 91.7％ (44/48),91.7％ (44/48) and 89.6％ (43/48),respectively.MIC50 of ciprofloxacin,levofloxacin and moxifloxacin was 2 mg/L,1 mg/L and ≤ 0.25 mg/L,respectively ; MIC90 was 4 mg/L,2 mg/L and 0.5 mg/L,respectively.Of the 48 isolates of Streptococcus pyogenes,12 isolates showed the MIC at 4 mg/L,while one isolate has a MIC against ciprofloxacin at 8 mg/L,which isolated from Chaoyang district.Analysis of sequence of chromosome mediated fluoroquinolone resistance genes in those 13 ciprofloxacin non-susceptible isolates exhibited that there were 12 isolates that harbored Ser79Phe/Tyr mutation and 10 isolates harbored Ala121Val in parC gene.It is shown that one isolate contained Ser79Phe mutation in parC gene in the occurring of Ser371Leu mutation in parE gene for the first time,but there was no marked increase in ciprofloxacin MIC (MIC =4 mg/L).There were no mutations in gyrA and gyrB genes.The PFGE results demonstrated that the 17 tested isolates could be divided into 7 clones.The clone A isolates from Chaoyang,Daxing,Fengtai,Shunyi and Shijingshan district have a MIC ≥ 4 mg/L against ciprofloxacin,which covered 69.2％ of all MIC ≥4 mg/L isolates.The clone C isolates from Huairou district were MIC ≥4 mg/L isolates.B,D,E,F and G clones isolates come from different districts.Conclusions The mutation of parC gene was the main reason that contribute to the slightly increase of ciprofloxacin MIC in Streptococcus pyogenes isolated from Beijing.The PFGE analysis showed that there was a small scale prevalence caused by the infection of Streptococcus pyogenes in some districts.

Diversidad genética de aislamientos peruanos de Leptospira spp. mediante electroforesis en gel de campo pulsado / Genetic diversity of Peruvian isolates of Leptospira spp. through pulsed field gel electrophoresis

Objetivos. Determinar la diversidad genética de aislamientos peruanos de Leptospira spp. mediante electroforesis en gel de campo pulsado (PFGE). Materiales y métodos. Se estandarizó la metodología de PFGE propuesta por Galloway y Levett (2008). Se elaboró una base de datos con los perfiles de PFGE de 65 cepas de referencia y se aplicó la técnica en 111 aislamientos de Leptospira spp. obtenidos en Perú entre 2002 y 2010. Resultados. Se determinó gran diversidad genética de serovares de Leptospira spp. circulantes en nuestro país. Se identificaron 57 serovares, 47 en 97 aislamientos patógenos. Los serovares más frecuentes fueron Icterohaemorrhagiae/Copenhageni (n=24) y Canicola (n=7). Las especies más frecuentes fueron L. santarosai (49,5%) y L. interrogans (37,1%). La distribución de especies, clusters y serovares varió según la fuente del aislamiento, el contexto ambiental y la procedencia. Conclusiones. Existe gran diversidad de serovares circulantes en el Perú, la cual está relacionada a la especie, el reservorio, el contexto ambiental y la procedencia del aislamiento. Se evidencia las relaciones genéticas y epidemiológicas entre aislamientos de diferentes fuentes, lo cual está relacionada a la especie, el reservorio, el contexto ambiental y la procedencia del aislamiento.

Objectives. Determine the genetic diversity of Peruvian isolations of Leptospira spp. through Pulsed Field Gel Electrophoresis (PFGE). Materials and methods. The PFGE methodology proposed by Galloway and Levett (2008) was standardized. A database including the PFGE profiles of 65 reference strains was prepared, and the technique was applied in 111 isolates of Leptospira spp. obtained in Peru between 2002 and 2010. Results. A great generic diversity of serovars of circulating Leptospira spp. was determined in our country. 57 serovars were identified, 47 out of 97 pathogen isolates. Most frequent serovars were Icterohaemorrhagiae/Copenhageni (n=24) and Canicola (n=7). The most frequent species were L. santarosai (49,5%) and L. interrogans (37,1%). The distribution of species, clusters and serovars changed according to the source of isolate, the environmental context and the origin. Conclusions. There is great diversity of circulating serovars in Peru. There are genetic and epidemiological relations among isolates of different sources, and this is related to species, reservoir, environmental context and the origin of the isolate.

Analysis of the brucella pathogen and its molecular genotype in Guangdong province / 中国地方病学杂志

Objective To analysis the etiology and molecular classification of brucella strains isolated in Guangdong province in 2010.Methods The strains of 19 brucella were verified and identified by some methods including traditional biology phenotype confirmation,PCR amplification and pulsed field gel electrophoresis (PFGE).Results On phenotype level,4 strains were brucella melitensis biovar 1,2 strains were brucella suis biovar 3,and the rest were brucella melitensis biovar 3,which were specific B genes positive strains,and the PFGE typing similar values ranging from 67.9％ to 100％.In addition to the four strains from Zhuhai for the outbreak,the homology was 100％,and the rest were sporadic cases.Conclusions Brucella cases,in Guangdong province,are highly sporadic and dispersed outbreaks.Compared with a few years ago,it shows species diversification,and brucella melitensis biovar 3 is still the dominant serotype.PFGE can be used to distinguish the three species of brucella,but it can't effectively distinguish the allotypes.

Methicillin-resistant Staphylococcus aureus DNA electrophoretic pattern: temporal changes in an endemic hospital environment / Patrón electroforético del ADN de Staphylococcus aureus resistente a la meticilina: cambios temporales en unmedio hospitalario endémico

Objective. To describe the analysis of geographical and temporal distribution of DNA profiles determined by pulsed-field gel electrophoresis (PFGE) of methicillin-resistant Staphylococcusaureus (MRSA) strains isolated from hospitalized patients in a tertiary care university hospital in Brazil. Methods. Ninety-nine samples of MRSA obtained from 89 patients in the period 1999–2004 were studied. MRSA strains were isolated from central venous catheters (33 isolates) and bloodstream infections (66 strains). PFGE with 20 units of SmaI restriction endonucleasewas used for genomic typing. Results. Analysis of DNA PFGE of 99 strains of MRSA revealed 26 profiles and theirrespective related profiles. The mean time interval for detecting MRSA infection was 26 days from hospital admission. Forty-nine patients (57.6%) had a recent hospitalization. The DNAPFGE MRSA profiles were distributed in three clonal groups—I, II, and III—according to the period of time when the MRSA strains were isolated. DNA PFGE MRSA profiles were spreadhomogeneously through all hospital wards. Conclusions. Changes in the distribution of DNA PFGE MRSA profiles were largely temporal, with clonal groups being replaced over time, without predominance in any hospitalward or any specific area of the hospital.

Objetivo. Analizar la distribución geográfica y temporal de los perfiles de ADN determinados mediante electroforesis en gel de campo pulsado (PFGE) de cepas de Staphylococcus aureus resistente a la meticilina (SARM) aisladas de pacientes internados en un hospital universitario de atención terciaria en el Brasil. Métodos. Se estudiaron 99 muestras de SARM obtenidas 89 de pacientes en el período1999–2004. Las cepas de SARM se aislaron de infecciones de catéteres venosos centrales (33 aislados) y del torrente sanguíneo (66 cepas). Para la tipificación genómica se empleó PFGE con 20 unidades de endonucleasa de restricción SmaI. Resultados. El análisis del ADN de 99 cepas de SARM mediante PFGE reveló 26 perfiles, con sus respectivos perfiles relacionados. El intervalo medio de detección de la infección por SARM fue de 26 días desde el ingreso al hospital. En 49 pacientes (57,6%) había habido una hospitalización previa reciente. Los perfiles de ADN de SARM determinados mediante PFGE se distribuyeron en tres grupos clonales —I, II y III— según el período en el que se aislaron las cepas de SARM. Estos perfiles de ADN se encontraban distribuidos de manera homogénea en todos los servicios del hospital. Conclusiones. Los cambios en la distribución de los perfiles de ADN de SARM determinados mediante PFGE fueron en gran medida temporales, con reemplazo de los grupos clonales con el transcurso del tiempo, y sin predominio en ningún servicio ni área específica del hospital.

The resistance of multi-drug resistant Acinetobacter baumannii to tigecycline / 中华检验医学杂志

Objective To investigate the resistance of Acinetobacter baumannii to clinical common antibiotics and new drug tigecycline. Methods Six hundred and two Acinetobacter baumannii isolates were collected from 2008 to 2009 in four teaching hospitals in Zhejiang province. Agar dilution method was used to detect the resistance of 13 clinical commom antibiotics, polymyxin B and tigecycline. Homology analysis of 24 multi-drug resistant Acinetobacter baumannii strains was used to investigate the relationship of each strain with the method of pulsed field gel electrophoresis. Results From 2008 to 2009, the Acinetobacter baumannii isolates of four teaching hospitals in Zhejiang province were mainly isolated from respiratory specimens with the number of 277 (86.0%) strains in 2009, the number of blood samples decreased from 15 (5.4%) strains in 2008 to 5 ( 1.5% ) strains in 2009, and there were no obvious change in other specimens. Acinetobacter baumannii strains were resistant to 13 clinical common antibiotics at different degree, fluctuated from 35.0% to 85.0%. Compared with the resistance in 2008, levofloxacin and tobramyxin decreased 0. 9% and 9.0% in 2009, respectively. However, the resistance of other antibiotics increased at different degree, the resistance of ceftriaxone and cefepime increased about 10.0%, and the resistance of imipenem and meropenem increased to 74.2% (239/602) and 70.8% (228/602) in 2009,respectively. Acinetobacter baumannii showed high resistance to tigecycline with the percent of 78.9% (475/602), while it was only 3.7% (22/602) for polymyxin B. There were six cloning types among the 24 Acinetobacter baumannii isolates, and the most common type was type A with the percent of 50%.Conclusions The resistance of tigecycline makes the situation of nosocomial infectious more serious. It is necessary to control the transmission of multi-drug resistant Acinetobacter baumannii immediately.

Intrahospital dissemination of carbapenem-resistant Acinetobacter baumannii and analysis of the infected patients' prognosis / 北京大学学报(医学版)

Objective:To assess the genetic relationship of clinical isolates of carbapenem-resistant A.baumannii (resistant to both imipenem and meropenem) from January 2007 to March 2008 in Peking University Third Hospital for measures to decrease the isolates; to investigate the characteristics of patients with carbapenem-resistant A. baumannii colonization or infection and to evaluate antibiotic treatment for health care-associated infections caused by carbapenem-resistant A. baumannii. Methods: The medical records of patients with carbapenem-resistant A. baumannii colonization or infection were reviewed. Antibiotic susceptibilities of the isolates were determined by the standardized disk-diffusion method and the clonal relationship of the isolates was analyzed by pulsed-field gel electrophoresis. Results: A total of 49 carbapenem-resistant A. baumannii strains were isolated from the 49 patients hospitalized during the study period and pulsed-field gel electrophoresis typing yielded 7 different patterns. A total of 45 (91.8%)genotyped strains showed clonal relationship. The most frequently identified predisposing factors were intensive care unit stay, invasive procedures, and hypoalbuminemia. Chronic obstructive pulmonary disease (12 cases) and cerebrovascular disease (10 cases) were the most common comorbid conditions.The mortality of patients with carbapenem-resistant A. baumannii infection was 38. 1% (8 of 21 patients), and the acute physiology and chronic health evaluation Ⅱ score, initial antibiotic therapy failure rate and the presence of hypoalbuminemia were significantly increased in the death group. Combination therapy regimens had higher success rates than monotherapy regimens (11/13, 84. 6% vs. 3/17,17.6%). Conclusion: There has been clonal spread of carbapenem-resistant A. baumannii strains among patients in our hospital since 2007. Intensive care unit stay, invasive procedures, hypoalbuminemia, chronic obstructive pulmonary disease and cerebrovascular disease were common in patients with carbapenem-resistant A. baumannii colonization or infection. Antibiotic combination therapy may be effective for carbapenem-resistant A. baumannii infection.