الفهرس 
REVIEW OF THE LITERATUREOnly 14 pages are availabe for public view
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Abstract
SUMMARY
Haemophilus influenzae is a small (1 µm × 0.3 µm), pleomorphic, gram negative coccobacillus. Some strains of H influenzae possess a polysaccharide capsule, and these strains are serotyped into 6 different types (a-f) based on their biochemically different capsules. The most virulent strain is H. influenzae type b (Hib). Some H. influenzae strains have no capsule and are termed nonencapsulated H. influenzae or nontypeable H. influenzae (NTHi).
The epidemiology of invasive infections caused by H. influenzae is distinct from non invasive infections. NTHi is a major cause of mucosal infections such as otitis media, sinusitis, conjunctivitis and exacerbations of chronic obstructive pulmonary disease, associated with the formation of biofilms.
Pulmonary disease, HIV infection (and other immunodeficiency states), alcoholism, pregnancy, and malignancy may predominate in adults with invasive Hib disease.
Encapsulated type b Haemophilus influenzae (Hib) was responsible for most of the invasive disease (meningitis) prior to the use of Hib vaccines. As Hib vaccines have no effect on infections due to nontypeable H. influenzae (NTHi), in areas where Hib vaccines are used, nontypeable strains are now the most common cause of invasive disease.
Initially, invasive and serious H influenzae type b (Hib) infections are best treated with an intravenous third-generation cephalosporin until antibiotic sensitivities become available. Antibiotics and supportive care are the mainstays of treatment.
It is important to monitor the resistance rates of H influenzae to different antibiotics to guide empiric antimicrobial choices while awaiting susceptibility results
There has been a steady increase in H. influenzae isolates resistant to ampicillin, including a high number of intrinsic resistance cases, and tracking of the epidemiology is challenging due to the genomic diversity of H. influenzae and its high prevalence of recombination.
The first beta-lactam-resistance mechanisms observed relied on the acquisition of the beta-lactamases blaTEM-1/2 and blaROB-1, and blaTEM-1 is the by far more prevalent gene. It moved via the associated Tn2/3 transposon onto a cryptic plasmid already present in H. influenzae, which can also integrate into the chromosome and carries several resistances. More recently distribution of mobile resistances was also described on small but conjugative plasmids, and transfer to Escherichia coli, as shown in vitro, indicates the possibility of inter-species resistance spread.
Five PBPs (1A, 1B, 2, 3, and 4) are known in H. influenzae. Alterations in one of them, PBP3, encoded by the ftsI gene, have been attributed to increased resistance to β-lactam antibiotics. Several mutations within its transpeptidase domain have been recognized, and some of them result in decreased affinity to penicillins as well as cephalosporins. Strains carrying altered PBPs have been named BLNAR (β-lactamase-negative ampicillin-resistant).
FDA categorizes Hib vaccine as a polysaccharide conjugate vaccine. In the United States, FDA licensed 3 monovalent conjugate Hib vaccines. They can be used in infants as young as 6 weeks of age.
In our study we aimed to identify the Haemophilus species isolated from clinical samples of patients referred to the Main Microbiology Laboratory, Ain Shams University Hospitals & determine its local resistance pattern.
During the study, fifty (50) different isolates of Haemophilus Influenzae isolated from different clinical specimens submitted to the Main Microbiology laboratory of Ain Shams University Hospitals were subjected to Subculture on chocolate agar, Phenotypic identification of colonies by routine methods including:Gram stain morphology, Culture morphology, Oxidase test (Oxoid, England), X & V Factors (Oxoid,England), then the identified isolates were subjected to antibiotic susceptibility testing by using disk diffusion method on HTM media according to Clinical and Laboratory Standard Institute recommendations (2020) and Multiplex PCR for detection of TEM & ROB genes.
Our results showed there was a significant realtion between ampicillin resistance and presence of TEM gene.