Hemophilus influenzae infections: part I

Miller Fisher Syndrome Triggered by Infections: A Review of the Literature and a Case Report

AIM

We reported a case of Miller Fisher syndrome following a breakthrough varicella zoster virus infection in an otherwise healthy 6-year-old male. The objective of this review was to summarize the infectious etiologic agents known to trigger Miller Fisher syndrome.

METHODS

Review of the literature on infections associated with Miller Fisher syndrome.

RESULTS

We identified 762 studies after duplicates were removed. Titles, abstracts, and full texts were screened. Finally, 37 studies were included in qualitative synthesis after citations and reference list were checked. The age range of cases reported was 0-78 years, and male sex was predominant in studies where these parameters were reported. The most common causative agent was Campylobacter jejuni followed by Haemophilus influenzae.

CONCLUSIONS

Our review highlights the importance of recognizing the infections triggering Miller Fisher syndrome. We also present a unique case of Miller Fisher syndrome associated with breakthrough varicella zoster virus infection. Preventive policies may consider population immunization for certain causative agents.

Miller Fisher Syndrome Triggered by Infections: A Review of the Literature and a Case Report

AIM

We reported a case of Miller Fisher syndrome following a breakthrough varicella zoster virus infection in an otherwise healthy 6-year-old male. The objective of this review was to summarize the infectious etiologic agents known to trigger Miller Fisher syndrome.

METHODS

Review of the literature on infections associated with Miller Fisher syndrome.

RESULTS

We identified 762 studies after duplicates were removed. Titles, abstracts, and full texts were screened. Finally, 37 studies were included in qualitative synthesis after citations and reference list were checked. The age range of cases reported was 0-78 years, and male sex was predominant in studies where these parameters were reported. The most common causative agent was Campylobacter jejuni followed by Haemophilus influenzae.

CONCLUSIONS

Our review highlights the importance of recognizing the infections triggering Miller Fisher syndrome. We also present a unique case of Miller Fisher syndrome associated with breakthrough varicella zoster virus infection. Preventive policies may consider population immunization for certain causative agents.

Rapid detection of Haemophilus influenzae by hel gene polymerase chain reaction

AIMS

To evaluate the efficiency of hel gene polymerase chain reaction (PCR) to detect Haemophilus influenzae in various clinical/non-clinical samples.

METHODS AND RESULTS

Seventy-four clinical samples (cerebrospinal fluid, blood, sputum, throat and nasal swabs) and throat swabs of 17 asymptomatic carriers were collected. Primers were used to amplify the hel gene of H. influenzae encoding P4 outer membrane protein directly from the processed samples. The samples were also examined by conventional culture methods and the results were compared with those of PCR. The culture methods showed positive results in 60 (65.9%) of 91 samples in contrast to 62 (68.12%) samples tested positive by PCR. None of the culture-positive samples were PCR-negative while two of the culture-negative samples were PCR-positive. The specificity of the products was confirmed by Southern hybridization and failure of various other organisms to amplify the hel gene product. The sensitivity of the PCR assay was found to be 50 pg of DNA.

CONCLUSIONS

These findings suggest that the hel gene PCR is a rapid, sensitive and a specific new method for direct identification of H. influenzae.

SIGNIFICANCE AND IMPACT OF THE STUDY

Thus, this PCR test can improve the detection rate of H. influenzae in suspected clinical samples as compared with that of conventional culture methods.

Comparison of amoxycillin/clavulanate with amoxycillin in children and adults with chronic obstructive pulmonary disease and infection with Haemophilus influenzae

71 children and adults (median age 7 years) with chronic obstructive pulmonary disease in which ampicillin-sensitive Haemophilus influenzae were isolated from lower airway secretions were included in a single-blind study comparing amoxycillin/clavulanate and amoxycillin alone. The dosage of amoxycillin was 50 mg/kg/day given together with probenecid and divided in 3 doses. Duration of treatment was 14 days. Clinical and bacteriological examinations were performed at study entry and again immediately after the treatment period. A late bacteriological follow-up 1.5 months after entry was performed. 65 patients were eligible for analysis of clinical outcome, and no difference between the groups was found. Side-effects were mild at a frequency of 3% for either preparation. In terms of eradication of the initially isolated H. influenzae amoxycillin/clavulanate tended to be better than amoxycillin, although the difference was not significant (70% and 57%, respectively). In a subset of 33 patients with polymicrobial flora amoxycillin/clavulanate was significantly more effective than amoxycillin. However, amoxycillin/clavulanate did not significantly reduce the emergency of beta-lactamase producing H. influenzae during treatment, and thus offers no advantage over amoxycillin in patients with amoxycillin-sensitive H. influenzae. The combination should be reserved to patients with either polymicrobial flora or ampicillin-resistant H. influenzae.

Genetic relationships of serologically nontypable and serotype b strains of Haemophilus influenzae

A collection of 242 strains of Haemophilus influenzae, including 65 nontypable (unencapsulated) isolates and 177 encapsulated serotype b isolates recovered largely from children with invasive and noninvasive diseases in the United States, was characterized by the electrophoretic mobilities of 15 metabolic enzymes presumably encoded by chromosomal genes. All enzymes were polymorphic for three to seven electromorphs, and 94 distinctive multilocus genotypes (electrophoretic types [ETs]) were distinguished, among which mean genetic (allelic) diversity was 0.500. Isolates recovered from cases of invasive or noninvasive diseases did not differ significantly in level of genetic variation. The observation that 29 ETs were represented exclusively by serotype b isolates and that each of the 65 nontypable isolates was of a unique ET strongly confirmed the hypothesis that unencapsulated clinical isolates are not merely phenotypic variants of the common serotype b cell lines. Rather, the two types of isolates are distinctive subsets of the multilocus chromosomal genotypes of the species as a whole. Serotype b capsule occurred in three groups of isolates that are distantly related in multilocus enzyme genotype. Isolates of four closely related nontypable biotype IV ETs associated with obstetrical infections or neonatal bacteremia were highly divergent from all others examined and may be specifically distinct. A phylogenetic scenario was proposed in which the ancestor of H. influenzae was encapsulated and the nontypable clones arose by convergent evolutionary loss of the ability to synthesize or extracellularly express a polysaccharide capsule.

Haemophilus organisms: urinary tract pathogens in children?

The incidence and significance of isolation of Haemophilus species from urine specimens was determined at a pediatric referral center. The incidence was 0.27%, and half the isolates were pathogens. Evaluation of incidence and a cost analysis led to the conclusion that routine efforts to isolate Haemophilus from urine are not cost-effective.