Antimicrobial susceptibility of Haemophilus influenzae strains isolated from invasive disease in Italy

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Variation in expression of HMW1 and HMW2 adhesins in invasive nontypeable Haemophilus influenzae isolates

<p>Abstract</p> <p>Background</p> <p>Among surface antigens of nontypeable <it>Haemophilus influenzae </it>(NTHi), the HMW1 and HMW2 proteins are the major adhesins promoting colonization of the upper respiratory tract. Since they are potential vaccine candidates, knowledge concerning variation in HMW proteins expression among clinical isolates is of great interest. In this study, expression of <it>hmw1A </it>and <it>hmw2A </it>genes was evaluated by quantitative real-time reverse transcription-PCR in 3 NTHi invasive isolates (strains 56, 72, 91) and in the prototype strain 12. Number of 7-bp repeats within the <it>hmwA </it>promoters and presence of HMW proteins by Western blotting were also determined.</p> <p>Results</p> <p>Results showed that gene transcription varied not only among different isolates but also between the <it>hmw1A </it>and <it>hmw2A </it>genes from the same isolate. Compared to that found in prototype strain 12, up-regulation of the <it>hmw1A </it>gene expression was found in strain 56, down-regulation of both <it>hmw1A </it>and <it>hmw2A </it>genes transcripts was observed in strain 72 whereas the two <it>hmwA </it>genes appeared differentially expressed in strain 91 with the <it>hmw1A </it>transcript enhanced but the <it>hmw2A </it>transcript reduced.</p> <p>Conclusion</p> <p>Increasing numbers of 7-bp repeats within the <it>hmwA </it>promoters generally correlated with decreased amounts of mRNA transcript, however additional control mechanisms contributing to modulation of <it>hmw1A </it>gene seem to be present.</p

Risk factors for Haemophilus influenzae and pneumococcal respiratory tract colonization in CVID

To the Editor: Disease-specific studies focused on infection risk in common variable immune deficiencies (CVIDs) are needed to define strategies for controlling respiratory infections predominantly due to bacteria such as Streptococcus pneumoniae and Haemophilus influenzae.1 Little information is available on the rate of airway bacterial carriage and its consequence in hypogammaglobulinemias. Despite IgG replacement, recurrent respiratory infections are common in CVID, possibly leading to chronic lung damage2 and poor quality of life.3 Thus, patients are often prescribed antibiotics and/or long-term antimicrobial prophylactic regimens. Several regimens are used including rotation or periodically changing antibiotics.4 However, antibiotics influence antimicrobial resistance among airway microbiota. In a recent meta-analysis on patients with chronic lung diseases, 30% of S pneumoniae showed resistance to macrolides.

Role of multispecies microbial biofilms in the occlusion of biliary stents

Endoscopic stenting is a standard palliative approach for the treatment of a variety of diseases involving biliary obstruction. However, the major limitation of this approach is represented by stent occlusion followed by life-threatening cholangitis, often requiring stent removal and replacement with a new one. Although it is generally believed that microbial colonization of the inner surface of the stent plays an important role in initiating the clogging process, so far available data are not enough for a full understanding of this phenomenon. In fact, it is known that when a biliary stent is inserted across the sphincter of Oddi, the loss of the antimicrobial barrier represented by the sphincter itself and the low pressure in the common bile duct allow reflux of duodenal content, thus promoting an ascending microbial colonization. The sessile mode of growth and the exopolysaccharide production, which leads to the subsequent establishment of a thick biofilm, provides microorganisms with an efficient protection from both antibacterial agents and phagocytic cells. The aim of this study was to analyze the tridimensional structure of the microbial biofilm grown in the lumen of 15 clogged biliary stents and to identify the microbial species involved in the clogging process. Scanning electron microscopy investigations revealed that sludge present in the stent lumen consist of a rich and assorted microbial flora, including aerobic and anaerobic species, mixed with a large amount of amorphous material containing dietary fibres, crystals of cholesterol and other precipitates of bacteria-driven bile salts. Key words: biliary stent, biofilm, microbial colonization, stent occlusio

Invasive Type e Haemophilus influenzae Disease in Italy

We describe the first reported cases of invasive type e Haemophilus influenzae disease in Italy. All five cases occurred in adults. The isolates were susceptible to ampicillin and eight other antimicrobial agents. Molecular analysis showed two distinct type e strains circulating in Italy, both containing a single copy of the capsulation locus

Genetic Characterization of the Capsulation Locus of Haemophilus influenzae Serotype e▿

The capsulation (cap) locus of Haemophilus influenzae type e (Hie) was characterized and sequenced. No IS1016 element was found to flank the locus. The 18.2-kb locus included 14 open reading frames (ORFs), which were grouped into three functional regions. Eight new ORFs (named ecs1 to ecs8) were identified in the Hie capsule-specific region II

Antibiotic Susceptibility and Molecular Typing of Invasive <i>Haemophilus influenzae</i> Isolates, with Emergence of Ciprofloxacin Resistance, 2017–2021, Italy

Haemophilus influenzae invasive disease is a severe infection that needs rapid antibiotic therapy. The aim of the study was to perform and evaluate the serotype distribution, antibiotic susceptibility and molecular characteristics of 392 H. influenzae invasive isolates collected during 2017–2021 in Italy. The majority of isolates were NTHi (305/392, 77.8%), followed by Hib (49/392, 12.5%). Ampicillin resistance was frequently detected (85/392, 21.7%): 12.2% were β-lactamase producers (all blaTEM except one blaROB), 9.4% were β-lactamase-negative ampicillin-resistant (BLNAR), with mutations in the ftsI gene. Six isolates were resistant to ciprofloxacin, with substitutions in GyrA and ParC. An MLST analysis revealed the occurrence of international resistant clones, such as ST103 and ST14, highlighting the importance of molecular surveillance