Fifty-five strains of Haemophilus influenzae recovered at a children's hospital in Korea from 1992 through 1997, were analyzed for serotype and antibiotic resistance. Antimicrobial susceptibility was tested by broth dilution method. Among the 55 strains, 26 were from normally sterile body fluids, of which 17 were from the immunocompetent children. Spectrum in the immunocompetent included meningitis (47%), bacteremic pneumonia (18%), and bacteremia without focus (35%). Three (12%) of 26 invasive infections were caused by non-type b: one type d and two type f. Nine of 29 non-sterile body fluid isolates belonged to one of encapsulted serotypes: four a, two c, one of each of b, d and e. Thirty two (58%) strains were resistant to ampicillin, and all of which produced beta-lactamase. All of the strains were highly susceptible to amoxicillin/clavulanate, cefixime, cefuroxime, azithromycin and ciprofloxacin, while 1 (2%), 7 (13%), 4 (7%) and 4 (7%) strains were intermediate to cefprozil, cefaclor, loracarbef, and clarithromycin, respectively. The serotype distribution of H. influenzae in Korean children is similar to those in developed countries before the introduction of Hib conjugate vaccine, and ampicillin resistance rate is among the highest published to date.
Antibiotics/pharmacology* ; Child ; Haemophilus Infections/microbiology* ; Haemophilus Infections/drug therapy ; Haemophilus Vaccines ; Haemophilus influenzae/isolation & purification ; Haemophilus influenzae/drug effects* ; Haemophilus influenzae/classification ; Human ; Korea ; Microbial Sensitivity Tests ; Serotyping

OBJECTIVETo investigate the serotypes and antibiotics-resistance patterns of Haemophilus influenzae isolated from children in Hangzhou.

METHODSIsolates were identified with api-NH card. Serotypes were determined with slide agglutination method. The sensitivities of 13 antibiotics against 247 strains of Haemophilus influenzae were determined in vitro with Kirby-Bauer diffusion methods and MICs of ampicillin were determined with E-test. Nitrocefin test was used to detect beta-lactamase.

RESULTSOf the 247 strains isolated from children during the period from August 2001 to July 2002, 153 strains were non-typable, while 94 strains (38.1%) were typable and 90.4% and 1.1% of them belonged to type d and type b, respectively. Higher incidence of typable Haemophilus influenzae was found in male than in female children and the difference was significant (chi(2) = 5.30, P < 0.05), while between upper and lower respiratory tract infected children the difference was not statistically significant (chi(2) = 3.60, P > 0.05). Forty-one isolates (16.6%) were beta-lactamase-positive and 14 strains could not grow on medium in antibiotics sensitivity test. Of all 233 isolates tested successfully, 85.4% were susceptible to ampicillin, and the sensitivity rate to cefaclor, ceftriaxone, cefotaxime, imipenem, rifampin, clarithromycin, and chloramphenicol were as high as 98.7%, 99.6%, 99.6%, 99.6%, 98.7%, 91.0%, and 90.6%, respectively. All strains were sensitive to amoxicillin/clavulanic acid, ampicillin/sulbactan and ofloxacin, while 107 strains (45.9%) were resistant to trimethoprim-sulfamethoxazole, followed by that of tetracycline (14.6%). Resistance to ampicillin and trimethoprim-sulfamethoxazole in typable isolates was statistically significantly higher than in non-typable strains. Twenty-six strains (10.5%) were multi-resistant isolates and the multi-resistance rate in beta-lactamase-positive strains were significantly higher than that in beta-lactamase-negative strains (chi(c)(2) = 146.8, P < 0.001).

CONCLUSIONNon-typable Haemophilus influenzae was the most common type in clinical strains isolated from children in Hangzhou, while type d was the overwhelming type and type b was uncommon in typable isolates. Incidence of typable isolates was higher in male than in female children, and it was apt to intergrow with other species of pathogenic bacteria. The proportion of beta-lactamase-positive strains was not high and ampicillin or other beta-lactam actibiotics were still the treatment of choice for infections with Haemophilus influenzae.

Anti-Bacterial Agents ; pharmacology ; Child ; China ; Drug Resistance, Multiple, Bacterial ; Haemophilus Infections ; microbiology ; Haemophilus influenzae ; classification ; drug effects ; isolation & purification ; Humans ; Microbial Sensitivity Tests ; Serotyping

OBJECTIVETo study the status of oral pharyngeal carriage and characteristics of Haemophilus influenzae (Hi) in healthy preschool children in Fuzhou.

METHODSSix hundred and three healthy children in two representative kindergartens in Fuzhou were studied as research subjects, and the rates of oral pharyngeal carriage of Hi were studied in four seasons. All Hi strains were serotyped and biotyped.

RESULTSThe oral pharyngeal carriage of Hi in day care nursery healthy children were 36.7% in winter, 18.0% in autumn, 12.4% in summer and 10.9% in spring respectively. Serotype Hib was preponderant in autumn (6.9%). In winter, the carriage rates of NTHi and Hib were 17.1%, 5.4% respectively. The carriage rates of other serotypes were low. Biotype VII and VIII were preponderant in autumn, spring and summer but biotype VII and VIII were decreasing evidently in winter.

CONCLUSIONThere was evident seasonal difference in the rates of oral pharyngeal carriage and type of Hi in healthy preschool children. The carriage rate of Hi strains was high in autumn and winter. Results suggested that while the inoculation of Hib-binding bacterial vaccine was expanded the study on new bacterial vaccine of Hi still needs to be augmented.

Carrier State ; epidemiology ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Haemophilus influenzae ; classification ; isolation & purification ; Humans ; Male ; Pharynx ; microbiology ; Seasons ; Serotyping

OBJECTIVETo establish multiplex PCR-based assays for detecting H.influenzae and H.parainfluenzae. And the PCR-based assays were applied to detect the carriage rates of H.influenzae and H.parainfluenzae in nasopharyngeal swab specimens which were collected from healthy children.

METHODSMultiplex primers for species-specific PCR were designed by using DNAstar soft based on the sequences of 16S rRNA genes from genus Haemophilus to detect H.influenzae and H.parainfluenzae.

RESULTSThe sensitivity of the 16S rRNA PCR assay for detecting H.influenzae and H.parainfluenzae was 97.53% and 100% respectively, and the specificity was 95.89% and 96.63% respectively. Youden's Index on the ability to detect H.influenzae and H.parainfluenzae was 0.9342 and 0.9663 respectively. 666 nasopharyngeal swab specimens were collected from healthy children. The detection rates of H.influenzae and H.parainfluenzae were 14.11% and 16.07% respectively by using isolation and culture methods. The detection rates of H.influenzae and H.parainfluenzae were 43.54% and 57.96% respectively by 16S rRNA PCR assays. The carriage rates of serotypes a, b, c, d, e, f and non-typeable isolates were 0% (0/666), 0.15% (1/666), 1.20% (8/666), 0.15% (1/666), 1.20% (8/666), 1.80% (12/666), 95.50% (636/666) respectively.

CONCLUSIONThe multiplex PCR assays were very rapid, reliable and feasible methods for detection of H.influenzae and H.parainfluenzae in pharyngeal swab specimens which were compared to conventional isolation and culture methods. 95.5% of H.influenzae strains in healthy children were nontypeable. The encapsulated or typable strains were mainly three serotypes which was c, e, and f serotype.

Haemophilus influenzae ; classification ; genetics ; isolation & purification ; Haemophilus parainfluenzae ; classification ; genetics ; isolation & purification ; Humans ; Multiplex Polymerase Chain Reaction ; methods ; Nasopharynx ; microbiology ; RNA, Bacterial ; genetics ; RNA, Ribosomal, 16S ; genetics ; Sensitivity and Specificity

OBJECTIVETo investigate the serotypes distribution and ampicillin resistance of Haemophilus influenzae isolates from children with respiratory infection in Hangzhou.

METHODSHaemophilus influenzae strains were identified with V factor and X factor tests. Serotypes were determined with the slide agglutination method. Nitrocefin test was used to detect beta-lactamase. The sensitivities of ampicillin to Haemophilus influenzae were determined with the Kirby-Bauer diffusion method and the E-test method.

RESULTSOne hundred and fifty-two Haemophilus influenzae isolates, 108 from boys and 44 from girls, were identified between December 2006 and July 2007. Of the 152 isolates, 148 (97.4%) were untypable, only 4 (2.6%) were typable, including type a, type d, type e and type f (n=1 each type). Haemophilus influenzae type b and c strain was not found. Thirty-four isolates (22.4%) were beta-lactamase-positive. One hundred and thirteen isolates (74.3%) were susceptible to ampicillin, while 34 isolates (22.4%) were resistant to ampicillin.

CONCLUSIONSUntypable strains were the most common in Haemophilus influenzae isolates from children with respiratory infection in Hangzhou. The isolates of Haemophilus influenzae kept susceptibity to ampicillin to a certain extent.

Adolescent ; Ampicillin Resistance ; Child ; Child, Preschool ; Female ; Haemophilus influenzae ; classification ; drug effects ; enzymology ; Humans ; Infant ; Infant, Newborn ; Male ; Microbial Sensitivity Tests ; Respiratory Tract Infections ; microbiology ; Serotyping ; beta-Lactamases ; analysis

The purpose of our experiment is to examine the level of anti-Haemophilus influenza polysaccharide antibody titer in the Korean population. Using ELISA, the level of Hib-PS antibodies in 384 infants and children who were all free from Hib invasive diseases, was tested. And the blood of 50 mothers within 24 hours of delivery and cord blood from their respective full-term neonates was also tested. The transport of Hib-PS IgG and IgG subclasses in paired sera from mothers and neonates was also measured. The titer of Hib-PS IgG varies with age. At birth the mean optical density of cord blood was 1.028; however, it declined to 0.609 up to 6 months and further decline was noted up to 2 years to 0.488. Then the mean O.D. remained around 0.5 from 3 to 14 years of age. The mean O.D. of Hib-PS IgG in the mothers blood was 0.856. The ratio of mean O.D. of anti-Hib PS IgG antibody in the cord blood to that in the maternal blood was 1.20. The mean optical densities of IgG subclasses were: 1.18 for anti-Hib PS IgG1, 1.07 for anti-Hib PS IgG2, 1.01 for anti-Hib PS IgG3, and 1.09 for anti-Hib PS IgG4. The sera from Korean children of almost all age groups reacted to Hib-PS antigen on ELISA. Also the active transport of anti-Hib PS IgG antibody through placenta was observed. Among four IgG subclasses, only IgG1 transport had significant experimental meaning.
Adolescent ; Adult ; Antibodies, Bacterial/*immunology ; Antigens, Bacterial/*immunology ; Bacterial Capsules ; Child ; Child, Preschool ; Enzyme-Linked Immunosorbent Assay ; Female ; Fetal Blood/immunology ; Haemophilus Vaccines/*immunology ; Haemophilus influenzae/*immunology ; Humans ; Immunoglobulin G/classification/immunology ; Infant ; Infant, Newborn ; Korea ; Male ; Maternal-Fetal Exchange ; Polysaccharides, Bacterial/*immunology ; Pregnancy

OBJECTIVEHaemophilus (H.) influenzae is a gram-negative bacillus that is a common commensal organism of the human upper respiratory tract and an important cause of human diseases such as pneumonia, meningitis, septicemia, epiglottitis and cellulitis. Strains of H. influenzae are classified according to their capsular polysaccharide. There are six serotypes, designated as a through f. In addition, there are nonencapsulated strains. Although the type of infectious diseases caused by H. influenzae has changed considerably in recent years because of the widespread and routine immunization of children against type b H. influenzae (Hib), Hib remains an important pathogen. Ampicillin is the drug of choice for treating many infections caused by H. influenzae, but its usefulness has been compromised by the increasing prevalence of ampicillin-resistant strains. The continued monitoring of resistant strains by using genotyping methods may provide insights into the epidemiology of transmission. A molecular epidemiological study of ampicillin-resistant H. influenzae derived from nasopharyngeal swabs specimens of children less than 5 years of age with respiratory tract infection were investigated in this study.

METHODSA total of 899 isolates were collected from Beijing, Shanghai, and Guangzhou during 2000-2003. Susceptibility to ampicillin was determined by using E-test. Ampicillin-resistant H. influenzae strains were selected according to National Committee for Clinical Laboratory Standards (NCCLS) 2002 breakpoints. Nested PCR method with primers specific for bexA gene and b capsulate type-specific gene was established. Genotyping by pulsed-field gel electrophoresis (PFGE) and multiplex PCR assay was performed for all ampicillin-resistant H. influenzae strains.

RESULTSSeventy-four ampicillin-resistant H. influenzae strains were obtained. Two strains were positive by nested PCR, characterized as b genotype. The incidence of Hib in ampicillin-resistant H. influenzae strains was 2.7%; 38 genotypes were detected by PFGE. Detection of five types strains of clonal dissemination by PFGE accounted for 55.4% in all ampicillin-resistant H. influenzae strains. Among them eighteen H. influenzae strains belonged to one type, accounted for 24.3% in all ampicillin-resistant H. influenzae strains. Thirty one genotypes were identified by multiplex PCR assay for ampicillin-resistant H. influenzae. The identity ratio of PFGE and multiplex PCR was 63.5%.

CONCLUSIONIn Beijing, Shanghai and Guangzhou areas 55.4% of ampicillin-resistant H. influenzae strains had clonal dissemination during the 4 years.

Ampicillin Resistance ; genetics ; Anti-Bacterial Agents ; pharmacology ; Child, Preschool ; China ; epidemiology ; DNA, Bacterial ; genetics ; Drug Resistance, Bacterial ; genetics ; Electrophoresis, Gel, Pulsed-Field ; Genotype ; Haemophilus Infections ; epidemiology ; microbiology ; Haemophilus influenzae ; classification ; genetics ; isolation & purification ; Humans ; Microbial Sensitivity Tests ; Molecular Epidemiology ; Nasopharynx ; microbiology ; Polymerase Chain Reaction ; Respiratory Tract Infections ; microbiology