جستجوی مقالات مرتبط با کلیدواژه « haemophilus influenzae » در نشریات گروه « پزشکی »

 Vulvovaginitis is a common infection in prepubertal girls, which is partly caused by bacterial infection. According to the literature, Haemophilus influenzae is one of the most common bacterial causes of vulvovaginitis in children. However, few studies with large sample sizes have delved into this issue.

 To determine the prevalence of Haemophilus influenzae vulvovaginitis in prepubertal girls and detect the antimicrobial resistance of H. influenzae strains isolated from vulval specimens.

 The isolates of H. influenzae from the vulval swabs of prepubertal girls with vulvovaginitis were received from The Children’s Hospital, Zhejiang University School of Medicine, during 2016 - 2019. The vulval specimens were inoculated on Haemophilus selective chocolate agar, and antimicrobial susceptibility tests were performed by the disk diffusion method. Moreover, β-lactamase was detected using Cefinase disc.

 In this study, 4142 vulval specimens were received during four years, of which 649 H. influenzae isolates had been isolated from 642 girls aged 6 months-13 years, with a median of 5 years. The peaks of isolates were observed from April to July in the vulval isolates. In general, the ampicillin resistance rate was 39.1% (250/640), 33.2% of strains (211/636) were β-lactamase-positive isolates, and 6.6% strains (42/635) were β-lactamase-negative ampicillin-resistant" (BLNAR)) isolates. The resistance rates of H. influenzae isolates to amoxycillin-clavulanic acid, ampicillin-sulbactam, cefuroxime, ceftriaxone, cefotaxime, meropenem, levofloxacin, sulfamethoxazole-trimethoprim, azithromycin, and chloramphenicol were 26.4%, 21.8%, 24.8%, 1.7%, 1.0%, 0.2%, 0%, 47.7%, 10.2%, and 1.1%, respectively. MDR was noticed in 41 persons (6.4%) out of the 642 H. influenzae isolates, with the most prevalent MDR phenotype of ampicillin-sulfamethoxazole-trimethoprim-azithromycin resistance.

 Clinicians should noticed that H. influenzae is a common bacterial cause of vulvovaginitis in children, and laboratories should routinely cover Haemophilus culture media for vulval specimens. The Ampicillin resistance of H. influenzae should also be considered in clinical management.

Haemophilusinfluenzae is an opportunistic pathogen of the human respiratory tract. Haemophilusinfluenzae can cause not only respiratory tract infection in children but also otitis media, epiglottitis and sinusitis. With the widespread use of antibiotics, the positive rate of β-lactamase in H. influenzae is increasing, and the rate of antimicrobial resistance is also increasing, which increases the difficulty of clinical treatment.

To study the infection characteristics of patients and the antibiotic resistance of H. influenzae in lower respiratory tract samples of children in Chengdu, so as to provide a reference for its clinical diagnosis and the rational use of antibiotics.

Sputum samples of 15891 children aged 0-14 years with lower respiratory tract infection were collected. Haemophilus influenzae was cultured and identified, its drug susceptibility tested, and the results determined according to the guidelines of CLSI 2020.

A total of 15891 clinical isolate strains in sputum were detected for drug sensitivity from December 2018 to January 2020, of which 5488 were H. influenzae, accounting for 34.54% (5488/15891). The sex of children infected with H. influenzae was not skewed (P > 0.05). The detection rate of H. influenzae was the highest in children aged 7 - 11 months, and the lowest was in the age group≤28 d. The detection rate was the highest in spring and the lowest in autumn. The positive rate of β-lactamase was 92.0%, the resistance rate to ampicillin was 92.0%, the sensitivity to amoxicillin/clavulanate was 70.2%, and the sensitivity to cefotaxime, ofloxacin, tetracycline, chloramphenicol, and rifampicin was more than 90.0%.

Children aged 7 months to 14 years were generally susceptible to H. influenzae in spring, and the positive rate of βlactamase was high. Doctors should refer to the infection characteristics and drug resistance of H. influenzae and choose antibiotics correctly to better control the infection.

 Adenoids act as reservoirs for pathogenic bacteria and chronic adenoid infection leads to its hypertrophy.

 The present study aimed to determine the frequency of Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae in children by polymerase chain reaction (PCR) and culture and to determine the antimicrobial resistance patterns of the isolates.

 In this cross-sectional study, 200 adenoid tissues were taken from children with adenoid hypertrophy in the operating room under general anesthesia conditions. The isolation and detection of bacteria were performed by culture and PCR methods. The antibiotic susceptibility patterns of the isolates were determined by the disc agar diffusion method according to the CLSI guidelines.

 Staphylococcus aureus was the most common bacterium (102; 51%) isolated by the culture method, followed by S. pneumoniae (44; 22%), M. catarrhalis (33; 16.5%), and H. influenzae (6; 3%). By multiplex PCR, the detection rate of microorganisms was as follows: S. aureus 40.5% (n = 81), S. pneumoniae 15.5% (n = 31), M. catarrhalis 11% (n = 22), and H. influenzae 4% (n = 8). Haemophilus influenzae strains were sensitive to all of the tested antibiotics. Seven S. aureus isolates were resistant to cefoxitin and identified as MRSA.

 This study showed the importance of S. aureus in the etiology of adenoid hypertrophy as the most frequent isolate. It may be due to the long-term duration of adenoid hypertrophy in children that helps the colonization of S. aureus in adenoid tissue and leads to chronic infection.

Bacterial meningitis is a devastating infection associated with significant morbidity and mortality rate among neonates and young children. Early identification and treatment of the causative agents of meningitis is crucial due to high fatality rate in untreated cases. The present study aimed to investigate the common bacterial etiology and occurrence of antimicrobial resistance in patients suspected to meningitis in southwestern Iran.

This retrospective cross-sectional study was conducted during a five-year period from January 2011 to January 2016 at two major hospitals in southwestern Iran. CSF samples were aseptically collected in BACTECTM, and conventional methods were used for the bacteria isolation and identification. Antimicrobial susceptibility tests were done using disk diffusion and E-test methods.

Out of 89 CSF samples collected from children under 17 years, the number of culture positive specimens was 21 (23.6%). The highest number of culture positive cases was observed in patients younger than 5 years (57.1 %). The most frequent pathogens were Streptococcus pneumonia (N = 10, 47.6%), followed by Haemophilus spp. (N = 3, 14.3%), and Neisseria meningitidis (N = 3, 14.3%). Antibacterial susceptibility testing results showed that S. pneumoniae isolates were mostly susceptible to vancomycin and chloramphenicol. Moreover, among N. meningitides and Haemophilus isolates, the most effective in vitro drug was ceftriaxone (100%).

These results showed the promising activity of several locally available antibiotics against S. pneumoniae, Haemophilus spp. and N. meningitides, as the most common causative agents of bacterial meningitis in Iranian children. Therefore, such regional studies help prevent and control the burden of infections.

Different serotypes of Haemophilus influenzae is now divided into 2 divisions: encapsulated and unencapsulated. Multiple locus variable number tandem repeat analysis (MLVA) includes such specifications as the extra power of separation, ease of data interpretation, and epidemiological data accordance, which have made it an appropriate molecular device for good typing and phylogenetic analysis of bacterial pathogens.
In this research, cultured samples were studied and strains identified through biochemical tests were recognized. Moreover, DNA was extracted and studied qualitatively and quantitatively. Four pairs of specialized primers related to H. influenzae variable number tandem repeats (VNTR) and preparation of PCR were designed according to the regulated program. Also, electrophoresis of PCR products was performed. Finally, the interpretation of electrophoresis gel was done with respect to the observable bands showing the presence or absence of the required sequence in the samples related to every primer.
This study was the first MLVA typing of the unencapsulated H. influenzae in Iran. In this research, the VNTR sequences were tested in 30 strains without the unencapsulated H. influenzae. Among 30 mentioned strains, for which MLVA profile was obtained in this research, 25 different MLVA types were observed. Likewise, there was no repetition in VNTR sequences resulting from PCR in few H. influenzae. In all these cases, the number of repetitions in MLVA profile was determined as 0, except for one of the primers in 4 strains, which was 16%. However, this did not occur for the other VNTRs.
The highest diversity of the repeats was for VNTR5 (7 types), followed by VNTR6 with 6 types of repeats, and VNTR12-1 and VNTR12-2 with 3 different types.

Nontypeable Haemophilus influenzae (NTHi) is responsible for diseases such as otitis media, sinusitis, bronchitis, and pneumonia. Unlike H. influenzae Serotype b (Hib), there is no vaccine against diseases induced by NTHi. High molecular weight1 (HMW1), high molecular weight 2 (HMW2), and H. influenzae type a (Hia) proteins are critical protein adhesions of NTHi with the potentiality to provide the protection.
The current study aimed at investigating the potential of recombinant HMW1555-914, HMW2553-916, and Hia585-705 proteins as subunit vaccines to induce immune responses after active immunization in Bagg albino (inbred research mouse strain) or Balb/c mice.
HMW1555-914, HMW2553-916, and Hia585-705 amplified by polymerase chain reaction (PCR) were cloned into pET28a. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the Western blotting analysis were carried out to investigate the characteristics of proteins. Proteins were purified by Ni-nitrilotriacetic acid (Ni-NTA) as a gel matrix. Mice (Balb/c) were immunized subcutaneously with HMW1555-914, HMW2553-916, and Hia585-705 proteins, alone or in binary and ternary combinations. Eventually, specific antibody responses were evaluated by the enzyme-linked immunosorbent assay (ELISA) and serum bactericidal assay (SBA).
Antibody responses significantly increased in Balb/c immunized by ternary combination compared with the control group. IgG1/IgG2a ratio indicated that proteins directed immune responses toward T-helper 2. Antisera produced against purified proteins in ternary combination showed the highest bactericidal activity against NTHi strains with the titer of 1:32.
The obtained results suggested that HMW1555-914, HMW2553-916, and Hia585-705 adhesins were the potential subunit vaccine candidates of NTHi and after further investigation could be considered for protection against NTHi infections.

Nonencapsulated, nontypeable Hemophilus influenzae (NTHi) remains an important cause of acute otitis and respiratory diseases in children and adults. NTHi bacteria are one of the major causes of respiratory tract infections, including acute otitis media, cystic fibrosis, and community-acquired pneumonia among children, especially in developing countries. The bacteria can also cause chronic diseases such as chronic bronchitis and chronic obstructive pulmonary disease in the lower respiratory tract of adults. Such bacteria express several outer membrane proteins, some of which have been studied as candidates for vaccine development. Due to the lack of effective vaccines as well as the spread and prevalence of NTHi worldwide, there is an urgent need to design and develop effective vaccine candidates against these strains.

Breastfeeding has been associated with decreased frequency of otitis media in children. It might be due to lower prevalence of nasopharyngeal colonization with the respiratory pathogens among breast-fed infants compared to those who are formula-fed.. This study was performed to determine the influence of breastfeeding on Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis colonization rates in children..Patients and In this cross-sectional study, 2 - 6 years old children in 10 randomly selected daycare centers in northeast of Iran (Mashhad) were studied. We obtained nasopharyngeal specimens to culture for Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis from 1125 children. Carriage rates for aforementioned bacteria were determined and analyzed on the basis of feeding type during infancy.. A total of 885 children were breast-fed (78.7%), 69 children were formula-fed (6.1%), and 171 children were mixed-fed (15.2%). Carriage rates of S. pneumoniae, H. influenzae and M. catarrhalis among children were 13.1%, 9.1%, and 4.3%, respectively. Although lower incidence of nasopharyngeal colonization was found in breast- versus formula-fed children, it was not significant (P > 0.5).. It seems that feeding in infancy has no influence over the prevalence of nasopharyngeal colonization with respiratory pathogens during childhood..

Haemophilus influenzae is a gram-negative bacterium causing a variety of respiratory infections in developing countries, especially in children. Nasopharynx carriers of H. influenzae are the prominent source and transitional vectors of invasive diseases. As very limited information on H. influenzae carriage rate in Iran was available, an evaluation on prevalence of this bacterium in children ≤ 6 years old seems crucial. Totally 533 mucus samples were collected using nasopharyngeal swabs from children ≤ 6 years old who lived in 4 nursery centers in Tehran or refereed to the Children''s Medical Center of Tehran, Iran, from August 2011 to October 2012. The samples were transported in Stuart transport medium to the Microbiology Laboratory of Pasteur Institute Tehran, Iran, and were cultured on chocolate agar containing bacitracin antibiotic. The initial diagnosis for detection of H. influenzae was performed by standard biochemical tests, and confirmation was achieved by PCR assay targeting outer membrane protein (omp) P6 gene. Based on primary cultures and biochemical tests, out of 533 samples, 182 (33%) showed to be H. influenzae positive, but PCR assay confirmed presence of H. influenzae in 153 (28%) isolates; 56(37%) belonged to girls and 97 (63%) to boys. The prevalence of H. influenzae in three different age groups: ≤ 24, 25-48, and 49-72 month-old children were 31 (20%), 69 (45%), and 53 (35%), respectively. Our results showed a high rate of H. influenzae carriers among children ≤ 6 years old, which is similar to those of other unvaccinated countries. H. influenzae carriage rate was associated to age and respiratory infection diseases. The children aged 25-48 months showed a higher rate and the rate reduced with increase in age. Further investigation including molecular studies is required to obtain the carriage rate throughout the country.

Based on many studies, otitis media with effusion (OME) is one of the major causes of childhood hearing loss, social malformation and medical costs. The pathogenesis still remains unclear, though it is known that this complication is closely related to bacterial infections. Alloiococcus otitidis, Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis are the most common bacterial pathogens isolated from middle ear effusions (MEEs). Due to the prevalence of OME in children, we decided to investigate bacterial agents that cause diseases such as A. otitidis, H. influenzae, S. pneumonia and M. catarrhalis in these subjects.Patients and Forty-five children between one and 15 years of age were selected for this study. Seventy specimens were collected from MEE by myringotomy and inoculated in PBS buffer. Conventional culture and PCR methods were used for identification of bacterial agents. The bacterial cultures in 8.6% of samples were positive by conventional culture, with A. otitidis, M. catarrhalis and S. pneumoniae present in 1.4%, 2.9% and 4.3% of samples, respectively. No H. influenzae was isolated. By the PCR method, A. otitidis was the most frequently isolated bacterium, found in 25.7% of samples, followed by S. pneumoniae, M. catarrhalis and H. influenzae, which were identified in 20%, 12% and 20% of samples, respectively. Overall, 55 out of 70 samples were positive by both the PCR and culture method. It can be concluded that A. otitidis was the major causative agent of MEE in children with OME. Therefore clinicians should be aware that bacterial infection plays an important role in the progression of acute otitis media to OME in children of our region.