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.

Extended-spectrum β-lactamase-producing Escherichia coli from extraintestinal infections in humans and from food-producing animals in Italy: a 'One Health' study

In recent years, Escherichia coli producing extended spectrum beta-lactamases (ESBL) have become a serious public health problem and food-producing animals (FPA) have been suggested as a potential reservoir/source. In this study, we aimed to compare ESBL-producing E. coli isolates from different sources. ESBL-producing E. coli isolates were collected from humans (n=480) and FPA (n=445) in Italy (2016-2017). Isolates were screened for the presence of ESBL and carbapenemase genes and classified according to phylogenetic group and MLST genotyping. mcr-1 to -5 genes were searched for in colistin resistant isolates. CTX-M was the most frequent ESBL-type in both human and animal isolates. CTX-M-15 prevailed in humans (75%) and cattle (51.1%) but not in poultry (36.6%). CTX-M-1 was common (58%) in pigs. SHV-type and CMY-2-like were found in FPA, especially in poultry (17.0% and 29.9%, respectively). 29 isolates were mcr-1 carriers (3 from humans and 26 from FPA). No carbapenemase genes were detected. Human isolates mostly belonged to phylogroup B2 (76.5%). Animal isolates were distributed among groups A (35.7%), B1 (26.1%) and C (12.4%). Few animal isolates (almost all from poultry) were classified into group B2 (4.3%). Most human isolates (83.4%) belonged to the pandemic ST131 clone and frequently carried CTX-M-15 (75.9%). ST131 was rarely detected in FPA (n=3 isolates from poultry). Nineteen STs were shared in both sources with ST10, ST410 and ST69 being more frequently detected. According to our results the potential exchange of ESBL genes from animals to humans is feasible, underlying the need for a strict monitoring based on an "One Health" approach

Rapid cross-border emergence of NDM-5-producing Escherichia coli in the European Union/European Economic Area, 2012 to June 2022

Whole genome sequencing data of 874 Escherichia coli isolates carrying blaNDM-5 from 13 European Union/ European Economic Area countries between 2012 and June 2022 showed the predominance of sequence types ST167, ST405, ST410, ST361 and ST648, and an increasing frequency of detection. Nearly a third (30.6%) of these isolates were associated with infections and more than half (58.2%) were predicted to be multidrug-resistant. Further spread of E. coli carrying blaNDM-5 would leave limited treatment options for serious E. coli infections

Invasive Haemophilus influenzae type b disease after widespread use of Hib conjugate vaccines in children

Sebbene i vaccini coniugati anti-Haemophilus influenzae type b (Hib) siano altamente protettivi, nel Regno Unito (UK) si è verificata un’inaspettata ricomparsa di malattie invasive da Hib anche in bambini vaccinati. Al fine di studiare i casi di fallimento vaccinale (TVF), abbiamo analizzato i livelli anticorpali anti-PRP nei casi di TVF in UK (1993 -1999). Abbiamo trovato che più della metà dei casi aveva una bassa concentrazione di anticorpi anti -PRP nel siero acuto, sebbene la maggior parte avev a un’adeguata concentrazione di anticorpi anti-PRP nel siero convalescente, in accordo con la presenza di memoria immunologica. Inoltre, dato che la maggior parte dei ceppi invasivi di Hib possiede una duplicazione del locus per la produzione della capsula (locus capb) ed è stata descritta ulteriore amplificazione (>2 copie), abbiamo investigato se l’amplificazione del locus capb possa avere un ruolo nei casi di TVF. Per questo motivo, il numero delle copie del locus capb è stato determinato nei ceppi di Hi b isolati da casi di TVF e da casi controllo (bambini non vaccinati con malattie invasive da Hib) della stessa classe di età in UK. Una proporzione significativamente più grande dei ceppi isolati da TVFs conteneva copie multiple, in confronto ai ceppi isolati dai controlli (24% vs. 10%; P=0.0379), suggerendo che l’amplificazione del locus capb possa contribuire ai casi di fallimento vaccinale. Per analizzare eventuali modificazioni nella struttura dei geni della capsula, nei ceppi di Hib circolanti in Itali a, dovute all’introduzione del vaccino anti-Hib nel programma vaccinale nazionale, abbiamo determinato il numero delle copie del locus capb nei ceppi invasivi di Hib isolati tra il 1997 e il 2003. E’ stato evidenziato un andamento temporale in crescita nel la proporzione dei ceppi con copie multiple del locus capb (P=0.03). I nostri risultati evidenziano la necessità di studiare ogni caso futuro di malattia invasiva da Hib.Although conjugate vaccines against Haemophilus influenzae type b (Hib) are highly protective, the United Kingdom have experienced an unexpected resurgence of cases of invasive Hib disease even in fully vaccinated children. To study true vaccine failure (TVF) cases, we examined the anti-PRP antibodies level in TVF cases from the UK (1993-1999). We found that over half of the cases had a low anti-PRP antibody concentration in acute serum, although most had a satisfactory convalescent phase anti-PRP antibody, in agreement with the presence of immunological memory. Moreover, since most invasive Hib strains possess a duplication of the capsulation locus and further amplification (>2 copies) has been described, we investigated whether amplification of t he capb locus might play a role in TVF cases. To this aim, the number of copies of the capb locus was determined in Hib strains isolated from TVF cases and from controls (unvaccinated children with invasive Hib disease) of the same age class in the UK. A significantly greater proportion of strains from TVFs contained multiple copies, compared with strains from controls (24% vs. 10%; P=0.0379), suggesting that amplification of the capb locus may contribute to vaccine failure. To investigate eventual changes in capsule gene structure among Hib strains circulating in Italy due to introduction of Hib vaccination in the nat ional vaccination program, we determined the number of cop ies of the capb locus in invasive Hib strains collected between 1997 and 2003. An upward temporal trend in proportion of strains possessing multiple copies of the capsulation b locus was detected (P=0.03). Our results underline the need to investigate each future case of invasive Hib disease

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