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

OBJECTIVE: To establish a biofilm model of Haemophilus influenzae and observe the effect of ambroxol on biofilm of Haemophilus influenzae and bactericidal action. METHOD: Thirty strains of Haemophilus influenzae were isolated from adenoids of children with adenoidal hypertrophy. Two strains which could build stronger biofilms was selected in a 96-well plate. The effect of ambroxol on biofilms were determined by crystal violet, and the structure of biofilms were observed by scanning electron microscope (SEM). The numbers of viable bacterial in biofilm after ambroxol treatmented determined by plate culture count. RESULT: Through crystal violet assay, significant difference (P < 0.01) between the two group after treatment was found when ambroxol concentration reached at 0.25 mg/ml and 0.49 mg/ml. The biofilms was destroyed by SEM. Ambroxol had the positive effect on bacterial killing by plate culture count,and the effect was in a dose dependent. CONCLUSION Ambroxol could destroy the biofilm of Haemophilus influenzae, and had bactericidal function in vitro.
Ambroxol ; pharmacology ; Biofilms ; drug effects ; Child ; Child, Preschool ; Haemophilus influenzae ; drug effects ; Humans ; Microbial Sensitivity Tests

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

AIMData is lacking with regard to the epidemiology of invasive haemophilus influenzae (HI) disease in Malaysia. This study was carried out to document the epidemiology of invasive HI disease in hospitalised Kelantanese children.

METHODSWe conducted a retrospective study of 65 children who had invasive HI disease from June 1985 to December 1994. Data regarding age, sex, duration of illness, weight, diagnosis, complications, duration of hospitalisation, outcome, full blood count and sensitivity pattern of HI to various antibiotics were reviewed.

RESULTSThe age distribution varied from one day to 72 months with a mean of 13 months. Peak incidence occurred in the 7-12 months age group. Majority (89.1%) was below two years of age. The relative frequencies of the 75 clinical entities documented were as follows: meningitis 64%, pneumonia 29.3%, septicaemia 5.4%, and abscess 1.3%. In addition, 13.5% of cases had meningitis associated with pneumonia. Serotype b accounted for all strains in cases where serotyping was done. Anaemia (Hb < 10 g%) was seen in 71.4% of cases. Long term complications were noted in 41.5% of cases of meningitis. Case fatality rate was 12.3%. The percentage of HI strains sensitive to penicillin, ampicillin, chloramphenicol and co-trimoxazole were 83.7%, 87.7%, 98.2% and 89.7%, respectively.

CONCLUSIONThe data suggest that invasive HI disease causes considerable morbidity and mortality in Kelantanese children.

Age Distribution ; Child, Preschool ; Drug Resistance, Microbial ; Female ; Haemophilus Infections ; epidemiology ; Haemophilus influenzae ; drug effects ; Humans ; Infant ; Infant, Newborn ; Malaysia ; epidemiology ; Male ; Retrospective Studies ; Seasons

The in vitro antibacterial activities of oral cephem antibiotics and ketolide telithromycin against major respiratory pathogens possessing beta-lactam-resistant mutations (within the pbp gene) and/or macrolide-resistant genes (erm and mef) were examined in clinical isolates collected at 66 institutes in all over the Japan between 2002 and 2003. Telithromycin showed the strongest antibacterial activity against methicillinsusceptible Staphylococcus aureus strains with and without macrolide-resistant genes, such as ermA or ermC gene. All the cephem antibiotics showed potent antibacterial activity against Streptococcus pyogenes, with minimum inhibitory concentrations (MICs) of 0.015 mg/L or lower. Cefdinir had a much higher MIC90 against genotypic penicillin-resistant Streptococcus pneumoniae (gPRSP) than cefditoren and cefcapene (8 mg/L cefdinir vs. 1 mg/L cefditoren and cefcapene). The majority of gPRSP harbored either ermB or mefA, and the antibacterial activity of telithromycin against these strains was decreased however some susceptibility was still sustained. Cefditoren exerted the strongest antibacterial activity against beta-lactamase-negative ampicillin-resistant Haemophilus influenzae, with an MIC90 of 0.5 mg/L. These results underline the importance of checking the susceptibility and selecting an appropriate antibiotic against target pathogens.
Streptococcus pyogenes/*drug effects ; Streptococcus pneumoniae/*drug effects ; Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Methicillin Resistance ; Ketolides/*pharmacology ; Humans ; Haemophilus influenzae/*drug effects ; Cephalosporins/*pharmacology ; Administration, Oral

BACKGROUNDIt is recognized that Haemophilus influenzae isolated from patients with otitis media forms biofilms both in vitro and in vivo, suggesting that biofilm formation in vivo might play an important role in the pathogenesis and chronicity of otitis media, but the effect of antibiotics on biofilm has not been well studied. We investigated the impact of ciprofloxacin and azithromycin on bacterial biofilms formed by Haemophilus influenzae in vitro in this study.

METHODSEleven strains of Haemophilus influenzae were isolated from sputum specimens collected from patients with acute exacerbation of chronic obstructive pulmonary diseases. Formation of bacterial biofilm was examined by crystal violet assay and a scanning electron microscope. Alterations of biofilms were measured under varying concentrations of azithromycin and ciprofloxacin.

RESULTSStriking differences were observed among strains with regard to the ability to form biofilm. Typical membrane-like structure formed by bacterial cells and extracellular matrix was detected. Initial biofilm synthesis was inhibited by azithromycin and ciprofloxacin at concentrations higher than two-fold minimal inhibitory concentration. Disruption of mature biofilms could be achieved at relatively higher concentration, and ciprofloxacin displayed more powerful activity.

CONCLUSIONSHaemophilus influenzae is capable of forming biofilm in vitro. Sufficient dosage might control early formation of biofilms. Ciprofloxacin exerts better effects on breakdown of biofilm than azithromycin at conventional concentration in clinics.

Anti-Bacterial Agents ; pharmacology ; Azithromycin ; pharmacology ; Biofilms ; drug effects ; Ciprofloxacin ; pharmacology ; Haemophilus influenzae ; drug effects ; isolation & purification ; Humans ; Lung Diseases, Obstructive ; microbiology ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning

Bacteria ; drug effects ; isolation & purification ; Drug Resistance ; Escherichia coli ; drug effects ; Female ; Haemophilus influenzae ; drug effects ; Humans ; Klebsiella pneumoniae ; drug effects ; Male ; Microbial Sensitivity Tests ; Respiratory Tract Infections ; microbiology ; Staphylococcus aureus ; drug effects ; Streptococcus pneumoniae ; drug effects

Child ; China ; Community-Acquired Infections ; microbiology ; Drug Resistance, Bacterial ; genetics ; Haemophilus influenzae type b ; drug effects ; genetics ; isolation & purification ; Humans ; Microbial Sensitivity Tests ; Pneumonia ; microbiology

Among 155 clinical respiratory isolates of Haemophilus influenzae in Korea, 6 (3.9%) isolates had reduced levofloxacin susceptibility (MICs > or = 0.5 microg/mL). These six isolates had no significant quinolone resistance-determining region (QRDR) mutations in gyrA, gyrB, parC, or parE. This phenomenon suggests that neither evolution nor spread of any significant QRDRs mutations in clinical isolates occurred in Korea. Therefore, continued surveillance is necessary to observe the evolution of antibiotic-resistance and take measures to avoid the spread of drug-resistant clones.
Anti-Bacterial Agents/*pharmacology ; DNA Gyrase/*genetics ; DNA Topoisomerases, Type II/*genetics ; Haemophilus influenzae/*drug effects/pathogenicity ; Korea ; Microbial Sensitivity Tests ; Mutation ; Ofloxacin/*pharmacology

Among 155 clinical respiratory isolates of Haemophilus influenzae in Korea, 6 (3.9%) isolates had reduced levofloxacin susceptibility (MICs > or = 0.5 microg/mL). These six isolates had no significant quinolone resistance-determining region (QRDR) mutations in gyrA, gyrB, parC, or parE. This phenomenon suggests that neither evolution nor spread of any significant QRDRs mutations in clinical isolates occurred in Korea. Therefore, continued surveillance is necessary to observe the evolution of antibiotic-resistance and take measures to avoid the spread of drug-resistant clones.
Anti-Bacterial Agents/*pharmacology ; DNA Gyrase/*genetics ; DNA Topoisomerases, Type II/*genetics ; Haemophilus influenzae/*drug effects/pathogenicity ; Korea ; Microbial Sensitivity Tests ; Mutation ; Ofloxacin/*pharmacology