Antimicrobial Activity of Omadacycline Tested against Clinical Bacterial Isolates from Hospitals in Mainland China, Hong Kong, and Taiwan: Results from the SENTRY Antimicrobial Surveillance Program (2013 to 2016)

Omadacycline is a derivative of minocycline and the first agent of the aminomethylcycline class. A total of 3,282 organisms (1 per patient) were consecutively collected from patients hospitalized in China (including Hong Kong) and Taiwan. Susceptibility testing was performed by broth microdilution methods in a central laboratory (JMI Laboratories). The collection included Gram-positive and Gram-negative organisms from patients with pneumonia, bloodstream, skin, community-acquired respiratory, and other infections. Omadacycline was very potent against Staphylococcus aureus (n = 689; MIC50/90, 0.12/0.25 mg/liter), including methicillin-resistant Staphylococcus aureus (MRSA; n = 299; MIC50/90, 0.12/0.5 mg/liter), and had similar activity across geographic regions. Omadacycline was very active against Streptococcus pneumoniae (highest MIC, 0.25 mg/liter), β-hemolytic streptococci (highest MIC, 1 mg/liter), viridans group streptococci (highest MIC, 0.25 mg/liter), and Enterococcus spp. (highest MIC, 0.5 mg/liter) from all geographic regions. Overall, 53.8% of S. pneumoniae isolates were penicillin resistant (penicillin MIC, ≥2 mg/liter) and 10.7% of enterococci (21.2% among E. faecium isolates) were vancomycin resistant. Omadacycline was active against Haemophilus influenzae (MIC50/90, 0.5/1 mg/liter) regardless of β-lactamase production and was active against Moraxella catarrhalis (MIC50/90, ≤0.12/0.25 mg/liter). Against Enterobacteriaceae, omadacycline was most active against Escherichia coli (MIC50/90, 1/2 mg/liter), Klebsiella oxytoca (MIC50/90, 1/4 mg/liter), and Enterobacter cloacae (MIC50/90, 2/4 mg/liter). Omadacycline had potent in vitro activity against Gram-positive and Gram-negative pathogens isolated from China and Taiwan and retained activity against problem pathogens, such as MRSA, vancomycin-resistant enterococci (VRE), penicillin-resistant S. pneumoniae (PRSPN), and extended-spectrum β-lactamase-producing E. coli The observed MIC profile in Chinese isolates was very similar to that seen in the U.S. and European surveillance studies.

Emergence of Haemophilus influenzae with low susceptibility to quinolones and persistence in tosufloxacin treatment

BACKGROUND

The use of non-β-lactam agents has increased in Japan due to the prevalence of β-lactam-resistant pathogens. This study aimed to clarify the recent trend of antimicrobial susceptibility and molecular epidemiological features in Haemophilus influenzae.

METHODS

Fifty-seven Haemophilus influenzae isolated from a Japanese teaching hospital in 2017 were characterised, and the data were compared with those of a previous study. The MICs were determined using the broth dilution method. Genetic backgrounds were compared by multilocus sequence typing. The bactericidal activity of tosufloxacin at, or near, the therapeutic Cmax was determined in vitro, with susceptible isolates and quinolone low-susceptible isolates by time-kill assay.

RESULTS

The results of the susceptibility tests showed that >90% of isolates were susceptible to cephalosporins and carbapenems, whereas ampicillin-susceptible and clarithromycin-susceptible isolates decreased. Regarding quinolones, low-susceptible isolates were noted in 2017, although all isolates were judged as susceptible. All low-susceptible isolates had an amino acid substitution in GyrA, and two isolates had an additional substitution in ParC. These isolates had different genetic backgrounds. Furthermore, the time-kill kinetic assay using the Cmax of tosufloxacin indicated that the low-susceptible isolates could persist for at least 8hours.

CONCLUSIONS

This study revealed that Haemophilus influenzae has demonstrated multidrug low-susceptibility in recent years. The low-susceptible isolates had genetic diversity, meaning that resistance occurred independently.

Bacterial regulation of macrophage bacterial recognition receptors in COPD are differentially modified by budesonide and fluticasone propionate

Rationale

Patients with COPD have an increased risk for community-acquired pneumonia, which is further increased by inhaled corticosteroids.

Objective

To assess effects of the corticosteroids, budesonide and fluticasone propionate, on macrophage bacterial responses in COPD.

Methods

Monocyte-derived macrophages (MDMs) generated from blood monocytes from 10 non-smoker controls (NoS), 20 smokers without COPD (Sm), and 40 subjects with moderate to severe COPD (21 ex-smokers (COPD-ES) and 19 current smokers (COPD-S)) were pre-treated with budesonide or fluticasone (10 nM—1 μM) and challenged with live non-typeable Haemophilus influenzae (NTHI) or Streptococcus pneumoniae (SP). Cell surface bacterial recognition receptor expression (flow cytometry) and cytokine release (bead array) were analyzed.

Results

NTHI and SP reduced bacterial recognition receptor expression on MDMs from COPD and Sm, but not NoS (except TLR4). SR-AI and MARCO were reduced by both NTHI and SP, whereas other receptors by either NTHI or SP. Among COPD subjects, COPD-ES demonstrated a greater number of reductions as compared to COPD-S. NTHI reduced SR-AI, MARCO, CD11b, CD35 and CD206 in COPD-ES while only SR-AI and CD11b in COPD-S. SP reduced SRA-1, CD1d, TLR2 and TLR4 in both COPD-ES and COPD-S, and reduced MARCO and CD93 only in COPD-ES. All receptors reduced in COPD by NTHI and most by SP, were also reduced in Sm. Budesonide counteracted the receptor reductions induced by both NTHI (CD206 p = 0.03, MARCO p = 0.08) and SP (SR-AI p = 0.02) in COPD-ES. Fluticasone counteracted only SP-induced reductions in TLR2 (p = 0.008 COPD-ES and p = 0.04 COPD-S) and TLR4 (p = 0.02 COPD-ES). Cytokine release was equivalently reduced by both corticosteroids.

Conclusions

Reduction in macrophage bacterial recognition receptors during bacterial exposure could provide a mechanism for the increased pneumonia risk in COPD. Differential effects of budesonide and fluticasone propionate on macrophage bacterial recognition receptor expression may contribute to the higher pneumonia incidence reported with fluticasone propionate.

Antimicrobial activity of ceftaroline and comparator agents tested against organisms isolated from patients with community-acquired bacterial pneumonia in Europe, Asia, and Latin America

OBJECTIVE

To evaluate the potency and spectrum of ceftaroline and comparator agents tested against contemporary bacteria isolated from patients with community-acquired bacterial pneumonia (CABP) in Europe (EUR), Asia-Pacific (APAC), and Latin America (LATAM).

METHODS

A total of 4321 bacterial isolates were collected consecutively by the SENTRY Antimicrobial Surveillance Program in 2015-2017 from 65 medical centers located in Western Europe (W-EUR; 21 centers in 10 nations), Eastern Europe and the Mediterranean region (E-EUR; 15 centers in 11 nations), APAC (18 centers in nine nations), and LATAM (11 centers in nine nations). Isolates were collected from lower respiratory tract specimens, and an isolate obtained from an outpatient or earlier than 48h after hospitalization was considered community-acquired. Organisms were tested for susceptibility by reference broth microdilution methods in a central laboratory.

RESULTS

Among Streptococcus pneumoniae (n=1736), 99.9% of isolates were ceftaroline-susceptible (MIC50/90, 0.008/0.12mg/l), and ceftriaxone susceptibility (≤1mg/l) ranged from 97.4% in W-EUR to 85.3% in the APAC region. Ceftaroline was also active against Haemophilus influenzae (n=1172; MIC50/90, 0.008/0.03mg/l; 99.8%/93.9% susceptible per CLSI/EUCAST criteria) and Staphylococcus aureus (n=777; MIC50/90, 0.25/1mg/l; 97.4% susceptible). Oxacillin resistance ranged from 31.9% in the APAC region to 15.0% in E-EUR. Ceftaroline also demonstrated potent activity against Moraxella catarrhalis (n=613; MIC50/90, 0.06/0.25mg/l) and Haemophilus parainfluenzae (n=23; MIC50/90, 0.015/0.03mg/l).

CONCLUSIONS

Susceptibility rates varied widely by geographic region. Ceftaroline was active against the vast majority of bacterial organisms isolated from patients with CABP.

Dexamethasone Inhibits Synergistic Induction of PDE4B Expression by Roflumilast and Bacterium NTHi

Phosphodiesterase 4B (PDE4B) plays an important role in inflammation. Recently we have reported that roflumilast as a PDE4-selective inhibitor, synergizes with nontypeable Haemophilus influenzae (NTHi) to up-regulate PDE4B expression in vitro and in vivo. Clinical evidence and our previous results suggest that synergistic induction of PDE4B could be counterproductive for suppressing inflammation or may contribute to tolerance to roflumilast. We thus investigated if dexamethasone inhibits the synergistic induction of PDE4B by roflumilast and NTHi as well as inflammation. Here, dexamethasone markedly suppressed the synergistic induction of PDE4B in human lung epithelial cells and in vivo. We also found that dexamethasone further suppressed NTHi-induced inflammatory response in vitro and in vivo. Moreover, Compound A, as a dissociating non-steroidal glucocorticoid receptor (GR) ligand, inhibited the synergistic induction of PDE4B, thereby suggesting the requirement of dexamethasone-mediated GR activation in the suppression of PDE4B expression. Taken together, our data suggest that dexamethasone may help attenuate inflammation and tolerance through suppressing the PDE4B expression in chronic obstructive pulmonary disease (COPD) patients using roflumilast.

Antibiotic resistance among bacterial conjunctival pathogens collected in the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study

The Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study evaluates in vitro antibiotic resistance among Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae isolates from ocular infections. Here we report resistance rates and trends among conjunctival-sourced ocular isolates collected across the US from 2009 through 2016. A total of 1198 conjunctival isolates (483 S. aureus, 305 CoNS, 208 H. influenzae, 118 S. pneumoniae, and 84 P. aeruginosa) were collected from patients with presumed bacterial conjunctivitis from 57 sites across 40 states. A large proportion of staphylococci demonstrated resistance to oxacillin and azithromycin, while resistance was low against the majority of antibiotics tested for S. pneumoniae, P. aeruginosa, and H. influenzae. Multidrug resistance (≥3 antibiotic classes) was found in 30.2% of S. aureus and 39.0% of CoNS isolates, and methicillin resistance more than doubled the rate of multi-drug resistance (methicillin-resistant S. aureus [MRSA], 76.5%; methicillin-resistant CoNS isolates, 72.8%). There was a pattern of increasing mean percent resistance with increasing age by decade of life among S. aureus, MRSA, and CoNS (P≤0.038). Over the eight-year study period, there were small yet significant decreases in resistance rates among S. aureus to azithromycin, ciprofloxacin, tobramycin, trimethoprim, and oxacillin (P≤0.003), and among CoNS and P. aeruginosa (both P<0.05) to ciprofloxacin. These data indicate that antibiotic resistance is high, but did not increase, among conjunctival-sourced isolates collected in the US from 2009 through 2016. For certain antibiotic/pathogen combinations, there was a trend of decreased resistance, including a decrease in oxacillin resistance among S. aureus.

Widening the antimicrobial spectrum of esters of bicyclic amines: In vitro effect on gram-positive Streptococcus pneumoniae and gram-negative non-typeable Haemophilus influenzae biofilms

Antibiotic resistance is a global current threat of increasing importance. Moreover, biofilms represent a medical challenge since the inherent antibiotic resistance of their producers demands the use of high doses of antibiotics over prolonged periods. Frequently, these therapeutic measures fail, contributing to bacterial persistence, therefore demanding the development of novel antimicrobials. Esters of bicyclic amines (EBAs), which are strong inhibitors of Streptococcus pneumoniae growth, were initially designed as inhibitors of pneumococcal choline-binding proteins on the basis of their structural analogy to the choline residues in the cell wall. However, instead of mimicking the characteristic cell chaining phenotype caused by exogenously added choline on planktonic cultures of pneumococcal cells, EBAs showed an unexpected lytic activity. In this work we demonstrate that EBAs display a second, and even more important, function as cell membrane destabilizers. We then assayed the inhibitory and disintegrating activity of these molecules on pneumococcal biofilms. The selected compound (EBA 31) produced the highest effect on S. pneumoniae (encapsulated and non-encapsulated) biofilms at very low concentrations. EBA 31 was also effective on mixed biofilms of non-encapsulated S. pneumoniae plus non-typeable Haemophilus influenzae, two pathogens frequently forming a self-produced biofilm in the human nasopharynx. These results support the role of EBAs as a promising alternative for the development of novel, broad-range antimicrobial drugs encompassing both Gram-positive and Gram-negative pathogens.

Antimicrobial susceptibility of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis clinical isolates from children with acute otitis media in Japan from 2014 to 2017

Increase in antimicrobial resistance (AMR) among pathogenic bacteria is a serious threat to public health. Surveillance studies to monitor shifting trends in resistance are important and guide the selection of appropriate antimicrobial agents for a particular organism. Furthermore, these studies help in dissemination of accurate information regarding AMR to the public. In this study, we investigated the antimicrobial susceptibility patterns of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis clinical isolates from outpatient children with acute otitis media in Japan from 2014 to 2017. A total of 8693 strains (2415 of S. pneumoniae, 3657 of H. influenzae, and 2621 of M. catarrhalis) were clinically isolated, and their antimicrobial susceptibilities to benzylpenicillin (PCG), ampicillin (ABPC), amoxicillin-clavulanic (AMPC/CVA), azithromycin (AZM), ceftriaxone (CTRX), and levofloxacin (LVFX) were investigated. Based on the minimum inhibitory concentration (MIC) breakpoints, the average proportion of S. pneumoniae isolates non-susceptible to PCG and AZM was 38.2% and 82.0% respectively. The average proportion of H. influenzae isolates non-susceptible to ABPC, CVA/AMPC, and CTRX was 61.9%, 43.5%, and 49.4%, respectively. The high prevalence of these resistant organisms is attributed to frequent use of antibiotic agents in Japan. Moreover, the proportion of LVFX-non-susceptible H. influenzae isolates increased in this four-year study. Here, we report updates regarding the AMR trends amongst the major pathogens that cause acute otitis media in Japan. Continuing surveillance of antimicrobial susceptibility and application of control measures against further transmission are required to decrease the emergence of resistant strains.

Transient Nutrient Deprivation Promotes Macropinocytosis-Dependent Intracellular Bacterial Community Development

Nutrient limitation restricts bacterial growth in privileged sites such as the middle ear. Transient heme-iron restriction of nontypeable Haemophilus influenzae (NTHI), the major causative agent of chronic and recurrent otitis media (OM), promotes new and diverse phenotypes that can influence planktonic, biofilm, and intracellular lifestyles of NTHI. However, the bacterial responses to nutrient restriction that impact intracellular fate and survival of NTHI are unknown. In this work, we provide evidence for the role of transient heme-iron restriction in promoting the formation of intracellular bacterial communities (IBCs) of NTHI both in vitro and in vivo in a preclinical model of OM. We show that transient heme-iron restriction of NTHI results in significantly increased invasion and intracellular populations that escape or evade the endolysosomal pathway for increased intracellular survival. In contrast, NTHI continuously exposed to heme-iron traffics through the endolysosomal pathway for degradation. The use of pharmacological inhibitors revealed that prior heme-iron status does not appear to influence NTHI internalization through endocytic pathways. However, inhibition of macropinocytosis altered the intracellular fate of transiently restricted NTHI for degradation in the endolysosomal pathway. Furthermore, prevention of macropinocytosis significantly reduced the number of IBCs in cultured middle ear epithelial cells, providing evidence for the feasibility of this approach to reduce OM persistence. These results reveal that microenvironmental cues can influence the intracellular fate of NTHI, leading to new mechanisms for survival during disease progression.IMPORTANCE Otitis media is the most common bacterial infection in childhood. Current therapies are limited in the prevention of chronic or recurrent otitis media which leads to increased antibiotic exposure and represents a significant socioeconomic burden. In this study, we delineate the effect of nutritional limitation on the intracellular trafficking pathways used by nontypeable Haemophilus influenzae (NTHI). Moreover, transient limitation of heme-iron led to the development of intracellular bacterial communities that are known to contribute to persistence and recurrence in other diseases. New approaches for therapeutic interventions that reduce the production of intracellular bacterial communities and promote trafficking through the endolysosomal pathway were revealed through the use of pharmacological inhibition of macropinocytosis. This work demonstrates the importance of an intracellular niche for NTHI and provides new approaches for intervention for acute, chronic, and recurring episodes of otitis media.

The return of Pfeiffer's bacillus: Rising incidence of ampicillin resistance in Haemophilus influenzae

Haemophilus influenzae, originally named Pfeiffer's bacillus after its discoverer Richard Pfeiffer in 1892, was a major risk for global health at the beginning of the 20th century, causing childhood pneumonia and invasive disease as well as otitis media and other upper respiratory tract infections. The implementation of the Hib vaccine, targeting the major capsule type of H. influenzae, almost eradicated the disease in countries that adapted the vaccination scheme. However, a rising number of infections are caused by non-typeable H. influenzae (NTHi), which has no capsule and against which the vaccine therefore provides no protection, as well as other serotypes equally not recognised by the vaccine. The first line of treatment is ampicillin, but there is a steady rise in ampicillin resistance. This is both through acquired as well as intrinsic mechanisms, and is cause for serious concern and the need for more surveillance. There are also increasing reports of new modifications of the intrinsic ampicillin-resistance mechanism leading to resistance against cephalosporins and carbapenems, the last line of well-tolerated drugs, and ampicillin-resistant H. influenzae was included in the recently released priority list of antibiotic-resistant bacteria by the WHO. This review provides an overview of ampicillin resistance prevalence and mechanisms in the context of our current knowledge about population dynamics of H. influenzae.

Multiclonal Expansion and High Prevalence of β-Lactamase-Negative Haemophilus influenzae with High-Level Ampicillin Resistance in Japan and Susceptibility to Quinolones

β-Lactam-resistant Haemophilus influenzae is a clinical concern. A high prevalence (>40%) of β-lactamase-negative high-level ampicillin-resistant H. influenzae (high-BLNAR) isolates in Japan has been reported. However, the reasons for the expansion are unknown. High-BLNAR strains possess an amino acid substitution, either Asn526Lys (group III) or Arg517His (group III-like) in addition to Ser385Thr, in penicillin-binding protein 3 (PBP3). To determine the current prevalence of high-BLNAR strains and the mechanisms behind their expansion in Japan, their prevalence, PBP3 types, multilocus sequence types, and susceptibilities to quinolones approved in Japan as alternatives were determined. Sixty percent of H. influenzae clinical isolates (62/104 isolates) were β-lactamase-negative ampicillin-resistant H. influenzae (BLNAR) strains. Among BLNAR isolates, 92% (57/62 isolates) were high-BLNAR strains. Most isolates were classified as belonging to group III, which contained many genotypes (11 PBP3 types and 25 sequence types). These results indicated that the expansion of high-BLNAR isolates was multiclonal and such strains are still predominant in Japanese clinical settings. One high-BLNAR isolate harbored the novel amino acid substitution Asn526Met in addition to Ser385Thr in PBP3, suggesting a new group (group IV). No quinolone-resistant H. influenzae isolates were identified. The MICs for the quinolones (moxifloxacin, garenoxacin, and tosufloxacin) were similar to that for levofloxacin, whereas sitafloxacin exhibited a lower MIC. However, we obtained 4 H. influenzae isolates with decreased quinolone susceptibility with the amino acid substitution Ser84Leu in GyrA, and 3 of those isolates were high-BLNAR isolates. In summary, this study shows that multiclonal high-BLNAR strains predominate in a Japanese university hospital. Isolates remain sensitive to quinolones, but vigilance is required to prevent the development of fluoroquinolone resistance in high-BLNAR strains.

Molecular characterization of fluoroquinolones, macrolides, and imipenem resistance in Haemophilus influenzae: analysis of the mutations in QRDRs and assessment of the extent of the AcrAB-TolC-mediated resistance

The aims of the present study were to characterize the mechanisms of resistance to fluoroquinolones, macrolides, and imipenem in Haemophilus influenzae, to assess the extent of the AcrAB-TolC-mediated resistance, and to define a core genome multilocus sequence typing (cgMLST) scheme for H. influenzae by using whole-genome sequencing. Four amino acid substitutions in GyrA (at Ser84 and Asp88), ParC (at Ser84), and ParE (at Asp420) were found to be closely associated to the MICs. We did not find any amino acid substitution surrounding the three highly conserved amino acid motifs in PBP3 related to imipenem resistance. All the isolates possessed the ermB gene. Carbonyl cyanide m-chlorophenylhydrazone (CCCP) decreased the MIC of imipenem by twofold for FQR-6 and fourfold for GE47 and GE88 strains. For erythromycin, the MICs were decreased by twofold. We found that the six FQR isolates were clustered in two groups. The number of different loci within FQR-1_FQR-3_FQR-5 cluster was 6, while FQR-2 and FQR-4 differed for 21 loci. FQR-1_FQR-3_FQR-5 and FQR-2_FQR-4 clusters were distant among each other and compared to 19 genomes downloaded from NCBI, to 8 strains heteroresistant to imipenem, and to 4 strains monoresistant to ciprofloxacin isolated in Denmark. We confirmed that specific amino acid substitutions in GyrA, ParC, and ParE are implicated in quinolone resistance. Additionally, the degree of resistance is related to the number of these amino acid substitutions. We provide robust evidence that drug efflux is one of the substantial mechanisms of imipenem and erythromycin resistance in H. influenzae.

Comparison of twice a day and three times a day meropenem administration in elderly patients in a Japanese community hospital

Meropenem (MEPM) is a broad-spectrum antibiotic prescribed to patients with moderate or severe pneumonia. It is well recognized that appropriate medicine reduces the burden on not only young patients but elderly ones as well. We enrolled 56 patients aged 75 and over who were diagnosed with moderate or severe pneumonia (body temperature: ≧37.5 °C; white blood cell (WBC) count: ≧10,000/μL; C-reactive protein (CRP): ≧4 mg/dL) on the basis of Clinical Evaluation Methods for New Antimicrobial Agents to Treat Respiratory Infections defined by the Japanese Society of Chemotherapy, at the National Hospital Organization Kanazawa Medical Center from January 1, 2007 to May 31, 2010. Forty-two patients were given MEPM twice a day and 14 were given the same drug three times a day in a Japanese community hospital. After four days, the three times a day group showed significant decreases in body temperature, WBC count, and CRP level, which are commonly used indices for evaluating therapeutic effects. Similarly, the twice a day group showed decreases of those indices, and both treatments had no serious adverse effects. Simulation analysis based on the pharmacokinetics-pharmacodynamics (PK/PD) theory revealed that both treatments effectively inhibited the activities of Pneumococcus, Haemophilus influenzae, Providencia stuartii, and Staphylococcus aureus, which are the major bacteria in the patients. In this retrospective study, simulation analysis based on the PK/PD theory revealed that even the twice a day MEPM administration has sufficient effectiveness against pneumonia. It also may pave the way for the use of personalized medicine in the patients.

A Cost-Effectiveness Analysis of the 10-Valent Pneumococcal Non-Typeable Haemophilus influenzae Protein D Conjugate Vaccine (PHiD-CV) Compared to the 13-Valent Pneumococcal Conjugate Vaccine (PCV13) for Universal Mass Vaccination Implementation in New Zealand

OBJECTIVES

Invasive pneumococcal disease (IPD), pneumonia and acute otitis media (AOM) still represent a significant medical burden in children < 5 years of age in New Zealand (NZ), with marked disparities across socio-economic and ethnic groups. This cost-effectiveness evaluation aims to compare the potential impact of two childhood universal immunisation strategies: vaccination with a 3 + 1 schedule of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV, Synflorix, GSK) and the 13-valent pneumococcal conjugate vaccine (PCV13, Prevenar 13, Pfizer).

METHODS

A static Markov-process cohort model was used to simulate the epidemiological and economic burden of pneumococcal diseases on a single-birth cohort over its lifetime. Costs and outcomes were discounted annually at 3.5%. Epidemiological and cost inputs were extracted from the most recently available NZ data, or derived from the most relevant reference countries' sources. The most updated evidence on the efficacies of the corresponding vaccines were used, particularly the significant effectiveness for PHiD-CV against IPD caused by serotype 19A.

RESULTS

The model estimated that both vaccines have a broadly comparable impact on IPD-related diseases and pneumonia. Due to the additional benefits possible through broader impact on AOM, PHiD-CV is estimated to potentially provide additional discounted cost offsets of approximately NZD 0.8 million over the lifetime of the birth cohort.

CONCLUSIONS

To ensure health equity in children, given the substantial burden of pneumonia and AOM, decision-makers should also take into account the impact of PCVs on these diseases for decisions relating to routine infant immunization.

GSK STUDY IDENTIFIER

HO-15-16775.

Pharyngeal colonization and drug resistance profiles of Morraxella catarrrhalis, Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae among HIV infected children attending ART Clinic of Felegehiwot Referral Hospital, Ethiopia

Background

Asymptomatic pharyngeal colonization by potential bacteria is the primary reservoir for bacterial species within a population and is considered a prerequisite for development of major childhood diseases such as sinusitis, otitis media, pneumonia, bacteremia, and meningitis. However, there is dearth of data on the colonization and drug resistance pattern of the main bacterial pathogens in the pharynx of HIV infected children in Ethiopia. Therefore, this study determined the pharyngeal colonization and drug resistance profile of bacterial pathogens in HIV infected children attending ART clinic of Felegehiwot Referral Hospital (FHRH), Amhara Region, Ethiopia.

Methods

A hospital based cross-sectional study was conducted from May 2016 to June 2017 at the ART clinic of FHRH. A total of 300 HIV infected children were enrolled in the study. Data on socio-demographic characteristics of the study participants were collected with face-to-face interview and patient—card review using structured questionnaire. Bacterial species were identified using standard bacteriological techniques. Drug susceptibility testing was performed using disk diffusion technique. Chi-square test was done to determine associations among variables.

Results

The median age of the participants was 11 years. Overall, 153 (51%) of children were colonized by respiratory bacteria in their pharynx. Colonization rate was higher in children from mothers who had attained college and above levels of education than others (P = 0.04). It was also higher in children without the sign of malnutrition than others (P = 0.004). The colonization rate of S.aureus, M.catarrhalis, S.pneumoniae and H.influenzae were 88 (29%), 37 (12.3%), 31 (10.3%) and 6 (2%), respectively. S.aureus—M.catarrhalis concurrent colonization was found in 14 (4.7%) of children. Age (P = 0.03), schooling (P = 0.045) and history of running nose (P = 0.043) were significantly associated with S.aureus colonization. Living in urban setting (P = 0.042) and children from mothers with college and above levels of education (P = 0.002) were significantly associated with M.catarrhalis colonization. Majority of the isolates were resistant to penicillin (68.5%) and cotrimoxazole (52.5%).S.aureus isolates were resistant to penicillin (84.1%) and cotrimoxazole (51.1%).M.catarrhalis isolates were resistant to penicillin (94.6%), erythromycin (86.5%)and cotrimoxazole (78.4%). Overall, 99 (59.3%) of the isolates were multi-drug (MDR) resistant. The overall MDR rates among S.aureus, M.catarrhalis and S.pneumoniae isolates were 65.9%, 78.4% and 22.6%, respectively.

Conclusions

Pharyngeal colonization of respiratory bacteria in HIV infected children is a major public health problem. Single and multiple antibiotic resistant is alarmingly high among respiratory colonizers. Therefore, regular screening of HIV infected children for culture and antimicrobial susceptibility testing is recommended to prevent the development of severe opportunistic infections.

[The bacteriologic features of recurrent acute rhinosinusitis]

Objective:To investigate the bacteriologic characteristics of recurrent acute rhinosinusitis(RAR).Method:Twenty-nine patients (29 with RAR) from outpatient clinic in our hospital between June 2010 and May 2016 were enrolled in the study. Specimens of the middle meatus or olfactory cleft area using the sinus endoscopy through were transported to the laboratory for bacterial culture.Result:Twenty-five specimens out of 29 were bacterial culture positive (culture positive rate was 86.2%).A total of 32 isolates (25 aerobic or facultative and 7 anaerobic) were recovered from the 29 cases of RAR. The predominant aerobic or facultative bacteria were Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus. The predominant anaerobic bacteria were Bacteroides fragilis and Propionibacterium. Antibiotic susceptibility tests showed that the resistance rate of these aerobic or facultative bacteria to Macrolides (Erythromycin and Azithromycin) and quinolones (Levofloxacin) was 88% and 92%, respectively. Similarly, the resistance rate of bacteria to β-lactamase antibiotics (penicillin, ampicillin, and cefazolin) was also greater than 90% (100%, 92%, and 92%, respectively). But the drug resistance of these bacteria to the thirdgeneration cephalosporin combined with beta lactamase inhibitors (Cefoperazone/sulbactam) was 20%. Among the 7 strains of anaerobic bacteria, 6 strains were sensitive to ornidazole.Conclusion:The major pathogens of RAR are the aerobic and facultative bacteria Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus, most of which are resistant to commonly used antibiotics.

Surveillance of tigecycline activity tested against clinical isolates from a global (North America, Europe, Latin America and Asia-Pacific) collection (2016)

Tigecycline and comparators were tested by the reference broth microdilution method against 33 348 non-duplicate bacterial isolates collected prospectively in 2016 from medical centres in the Asia-Pacific (3443 isolates), Europe (13 530 isolates), Latin America (3327 isolates) and the USA (13 048 isolates). Among 7098 Staphylococcus aureus isolates tested, >99.9% were inhibited by ≤0.5 mg/L tigecycline (MIC_50/90, 0.06/0.12 mg/L), including >99.9% of methicillin-resistant S. aureus and 100.0% of methicillin-susceptible S. aureus. Tigecycline was slightly more active against Enterococcus faecium (MIC_50/90, 0.03/0.06 mg/L) compared with Enterococcus faecalis (MIC_50/90, 0.06/0.12 mg/L) and its activity was not adversely affected by vancomycin resistance when tested against these organisms. Tigecycline potency was comparable for Streptococcus pneumoniae (MIC_50/90, 0.03/0.06 mg/L), viridans group streptococci (MIC_50/90, 0.03/0.06 mg/L) and β-haemolytic streptococci (MIC_50/90, 0.06/0.06 mg/L) regardless of species and penicillin susceptibility. Tigecycline was active against Enterobacteriaceae (MIC_50/90, 0.25/1 mg/L; 97.8% inhibited at ≤2 mg/L) but was slightly less active against Enterobacteriaceae isolates expressing resistant phenotypes: carbapenem-resistant Enterobacteriaceae (MIC_50/90, 0.5/2 mg/L; 98.0% susceptible); multidrug-resistant (MIC_50/90, 0.5/2 mg/L; 93.1% susceptible); and extensively drug-resistant (MIC_50/90, 0.5/4 mg/L; 87.8% susceptible). Tigecycline inhibited 74.4% of 888 Acinetobacter baumannii isolates at ≤2 mg/L (MIC_50/90, 2/4 mg/L) and demonstrated good in vitro activity against Stenotrophomonas maltophilia (MIC_50/90, 1/2 mg/L; 90.6% inhibited at ≤2 mg/L) Tigecycline was active against Haemophilus influenzae (MIC_50/90, 0.12/0.25 mg/L) regardless of β-lactamase status. Tigecycline represents an important treatment option for resistant Gram-negative and Gram-positive bacterial infections.

Children with respiratory tract infections in Swedish primary care; prevalence of antibiotic resistance in common respiratory tract pathogens and relation to antibiotic consumption

BACKGROUND

The majority of antibiotics consumed in developed countries are prescribed in primary care. However, little is known about resistance levels in the primary care population.

METHOD

Nasopharyngeal cultures were obtained from children, 0-10 years of age, seeking care at their Primary Health Care Centre with symptoms of respiratory tract infection. Parental questionnaires were used to retrieve information about the child's previous antibiotic consumption.

RESULT

Cultures from 340 children were gathered. The level of resistant Haemophilus influenzae was low and the prevalence of penicillin non-susceptible pneumococci (PNSP MIC ≥ 0.125 mg/L) was 6% compared to 10% (p = 0.31) in corresponding cultures from children diagnosed at the local clinical microbiology laboratory. Antibiotic treatment within the previous 4 weeks predisposed for resistant bacteria in the nasopharynx, OR: 3.08, CI 95% (1.13-8.42).

CONCLUSION

Low prevalence of PNSP supports the use of phenoxymethylpenicillin as empirical treatment for childhood upper respiratory tract infections attending primary care in our setting. It is important that studies on resistance are performed in primary care populations to evaluate data from microbiological laboratories. Recent antibiotic treatment increases risk of bacterial resistance in children and continuous work to reduce unnecessary antibiotic prescribing should be prioritised.

β-Lactam resistance among Haemophilus influenzae isolates in Poland

OBJECTIVES

Haemophilus influenzae is a human-specific Gram-negative coccobacillus responsible for a significant number of respiratory tract infections and severe invasive infections such as meningitis and sepsis. The purpose of this study was to characterise the mechanisms of β-lactam resistance among Polish H. influenzae isolates and to evaluate the resistance detection methods applied.

METHODS

This study was conducted on 117 Polish H. influenzae isolates collected in 2012. Minimum inhibitory concentrations were assessed by broth microdilution. All strains were evaluated using the disk diffusion method and the algorithm proposed by the Nordic Committee on Antimicrobial Susceptibility Testing (NordicAST). To detect changes in penicillin-binding protein 3 (PBP3), PCR screening was performed, followed by ftsI gene sequencing.

RESULTS

Neither β-lactamase production nor PBP3 alterations were demonstrated in 76 isolates (65.0%). Susceptibility to ampicillin, amoxicillin, amoxicillin/clavulanic acid, cefuroxime (intravenous) and ceftriaxone was observed in 70.9%, 78.6%, 98.3%, 82.9% and 100% of the isolates, respectively. β-Lactamase production characterised 21 isolates (17.9%). Screening PCR identified 20 isolates (17.1%) with PBP3 alterations, and according to subsequent ftsI sequencing all these strains were finally recognised as gBLNAR (genetically β-lactamase-negative, ampicillin-resistant), among which 65.0% were ampicillin-resistant. According to molecular classification of PBP3 alterations, 95.0% of gBLNAR belonged to group II, representing four subgroups IIa-IId.

CONCLUSIONS

Haemophilus influenzae resistance to antibiotics requires continuous attention, effective detection methods and a rational policy of antibiotic usage. The algorithm proposed by NordicAST can be applied in routine laboratory work, whereas sequencing of the ftsI gene may be useful in molecular epidemiology studies.

Ceftaroline Activity Tested Against Bacterial Isolates Causing Community-acquired Respiratory Tract Infections and Skin and Skin Structure Infections in Pediatric Patients From United States Hospitals: 2012-2014

Ceftaroline fosamil has recently received US Food and Drug Administration approval for treatment of acute bacterial skin/skin structure infections (SSSIs), including those caused by methicillin-resistant Staphylococcus aureus and community-acquired bacterial pneumonia for pediatric patients ≥2 months old. We evaluated the potency and spectrum of ceftaroline and comparators when tested against community-acquired respiratory tract infection (CARTI) and SSSI pathogens from pediatric patients. A total of 3141 consecutive, unique pediatric patient isolates of clinical significance (1460 CARTI and 1681 SSSI isolates) were collected from 29 US medical centers and tested for susceptibility to ceftaroline and comparators by broth microdilution methods. The organism collection included Streptococcus pneumoniae (n = 754), Haemophilus influenzae (487), S. aureus (1399), β-hemolytic streptococci (214), Enterobacteriaceae (112), Pseudomonas aeruginosa (58), Klebsiella spp. (39), Escherichia coli (26) and miscellaneous other bacteria (52). Susceptibility results were analyzed according to patient age as follows: ≤1, 2-5, 6-12 and 13-17 years old. Overall, 99%-100% of Gram-positive isolates and H. influenzae were susceptible to ceftaroline according to Clinical and Laboratory Standards Institute clinical breakpoint criteria. Ceftaroline exhibited potent in vitro activity against bacterial pathogens from CARTI and SSSI recently (2012-2014) collected from pediatric patients in US medical centers. Ceftaroline was particularly active against methicillin-resistant S. aureus from SSSI ([minimum inhibitory concentration for 50% and 90% of isolates (MIC50/90,)] and ceftriaxone-nonsusceptible isolates of S. pneumoniae from CARTI (MIC50/90, 0.25/0.5 μg/mL; 98.3% susceptible).

Performance Evaluation of a Newly Developed and Fully Automated Bacteriological Analyzer "RAISUS ANY" for Antimicrobial Susceptibility Testing of Fastidious Bacteria Haemophilus influenzae and Streptococcus pneumoniae

OBJECTIVE

Antimicrobial susceptibility testing for fastidious bacteria, such as Haemophilus influenzae (H. influenzae) and Streptococcus pneumoniae (S. pneumoniae) has been performed manually. We evaluated the performance of a newly developed fully automated system for rapid bacterial identification and antimicrobial susceptibility testing "RAISUS ANY" (Nissui Pharmaceutical Co., Ltd.).

METHODS

We evaluated the performance of "RAISUS ANY" for measurement of minimal inhibitory concentrations (MICs) of H. influenzae and S. pneumoniae, in comparison with the manual method (DP34, Eiken Chem. Co., Ltd.). The repeatability of MICs was studied using the reference strain of these bacteria, obtained from the American Type Culture Collection (ATCC, Manassas, VA, USA).

RESULTS

The comparison with the manual method for 35 and 36 clinical strains of H. influenzae and S. pneumonia showed 62.9-100% and 86.1-100% agreement, respectively. Five of 35 H. influenzae strains that showed a trailing effect were stably and accurately measured for MICs without a variation among the examiners.

CONCLUSION

In conclusion, the automated system "RAISUS ANY" provided a reliable MICs data for H. influenzae and S. pneumonia, suggesting its improvement in performance and reliability for routine antimicrobial susceptibility testing in clinical bacteriological laboratories.

Prevention of influenza virus induced bacterial superinfection by standardized Echinacea purpurea, via regulation of surface receptor expression in human bronchial epithelial cells

Viral infections may predispose the airways to secondary bacterial infections that can lead to unfavorable progression of principally self-limiting illnesses. Such complicated respiratory infections include pneumonia, bronchitis, sinusitis, acute otitis media, and sepsis, which cause high morbidity and lethality. Some of the pathogenic consequences of viral infections, like the expression of bacterial adhesion receptors and the disturbance of physical barrier integrity due to inflammation, may create permissive conditions for co-infections. Influenza virus A (H3N2) is a major pathogen that causes secondary bacterial infections and inflammation that lead to pneumonia. The herbal medicine Echinacea purpurea, on the other hand, has been widely used to prevent and treat viral respiratory infections, and recent clinical data suggest that it may prevent secondary infection complications as well. We investigated the role of standardized E. purpurea (Echinaforce^® extract or EF) on H3N2-induced adhesion of live nontypeable Haemophilus influenzae (NTHi) and Staphylococcus aureus, along with the expression of bacterial receptors, intracellular adhesion molecule-1 (ICAM-1), fibronectin, and platelet activating factor receptor (PAFr), by BEAS-2B cells. Inflammatory processes were investigated by determining the cellular expression of IL-6 and IL-8 and the involvement of Toll-like receptor (TLR-4) and NFκB p65. We found that influenza virus A infection increased the adhesion of H. influenzae and S. aureus to bronchial epithelial cells via upregulated expression of the ICAM-1 receptor and, to some extent, of fibronectin and PAFr. Echinaforce (EF) significantly reduced the expression of ICAM-1, fibronectin, and PAFr and consequently the adhesion of both bacterial strains. EF also effectively prevented the super-expression of inflammatory cytokines by suppressing the expression of NFκB and possibly TLR-4. These results indicate that E. purpurea has the potential to reduce the risk of respiratory complications by preventing virus-induced bacterial adhesion and through the inhibition of inflammation super-stimulation (cytokine storms).

Etiology of Acute Otitis Media in Children Less Than 5 Years of Age: A Pooled Analysis of 10 Similarly Designed Observational Studies

BACKGROUND

Acute otitis media (AOM) is an important cause of childhood morbidity and antibiotic prescriptions. However, the relative importance of the well-known otopathogens, Streptococcus pneumoniae (Spn) and Haemophilus influenzae (Hflu), remains unclear because of a limited number of tympanocentesis-based studies that vary significantly in populations sampled, case definitions and heptavalent pneumococcal conjugate vaccine use.

METHODS

We conducted a pooled analysis of results from 10 AOM etiology studies of similar design, the protocols of which were derived from a common protocol and conducted in children 3 months to 5 years of age in different countries. Generalized estimating equations were used to account for within-study correlations.

RESULTS

The majority, 55.5% (95% confidence interval: 47.0%-65.7%) of 1124 AOM episodes, were bacterial pathogen positive: 29.1% (24.8%-34.1%) yielded Hflu and 23.6% (19.0%-29.2%) Spn. Proportions of Hflu and Spn were higher and lower, respectively, in heptavalent pneumococcal conjugate vaccine-vaccinated children. Hflu and Spn were each isolated from 20% to 35% of children in every 1-year age range. Hflu was less likely to be isolated from first (vs. subsequent) episodes [relative risk (RR): 0.71 (0.60-0.84)]. Spn was more often isolated from sporadic (vs. recurrent) cases [RR: 0.76 (0.61-0.97)]; the opposite was true for Hflu [RR: 1.4 (1.00-1.96)]. Spn cases were more likely to present with severe (vs. mild) symptoms [RR: 1.42 (1.01-2.01)] and Hflu cases with severe tympanic membrane inflammation [RR: 1.35 (1.06-1.71)].

CONCLUSIONS

Spn and Hflu remain the leading otopathogens in all populations examined. While associated with overlapping symptoms and severity, they exhibit some differences in their likelihood to cause disease in specific subpopulations.

Population Pharmacokinetics and Pharmacodynamics of Levofloxacin in Acutely Hospitalized Older Patients with Various Degrees of Renal Function

A retrospective study was conducted in a large sample of acutely hospitalized older patients who underwent therapeutic drug monitoring during levofloxacin treatment. The aim was to assess the population pharmacokinetics (popPK) and pharmacodynamics of levofloxacin among older patients. PopPK and Monte Carlo simulation were performed to define the permissible doses in older patients according to various degrees of renal function. Classification and regression tree (CART) analysis was used to detect the cutoff 24-hour area under the concentration-time curve (AUC24)/MIC ratio that best correlated with the clinical outcome. The probability of target attainment (PTA) of this value was calculated against different pathogens. A total of 168 patients were included, and 330 trough and 239 peak concentrations were used for the popPK analysis. Creatinine clearance (CrCL) was the only covariate that improved the model fit (levofloxacin CL = 0.399 + 0.051 × CrCLCKD-EPI [creatinine clearance estimated by means of the chronic kidney disease epidemiology]). Drug doses ranged between 500 mg every 48 h and 500 mg every 12 h in relation to different renal functions. The identified cutoff AUC24/MIC ratio (≥95.7) was the only covariate that correlated with a favorable clinical outcome in multivariate regression analysis (odds ratio [OR], 20.85; 95% confidence interval [CI], 1.56 to 186.73). PTAs were optimal (>80%) against Escherichia coli and Haemophilus influenzae, borderline against Staphylococcus aureus, and suboptimal against Pseudomonas aeruginosa The levofloxacin doses defined in our study may be effective for the treatment of infections due to bacterial pathogens, with an MIC of ≤0.5 mg/liter in older patients with various degrees of renal function, while minimizing the toxicity risk. Conversely, the addition of another active antimicrobial should be considered whenever treating infections caused by less susceptible pathogens.

N-Acetyl-l-Cysteine and Cysteamine as New Strategies against Mixed Biofilms of Nonencapsulated Streptococcus pneumoniae and Nontypeable Haemophilus influenzae

Acute otitis media, a polymicrobial disease of the middle ear cavity of children, is a significant public health problem worldwide. It is most frequently caused by encapsulated Streptococcus pneumoniae and nontypeable Haemophilus influenzae, although the widespread use of pneumococcal conjugate vaccines is apparently producing an increase in the carriage of nonencapsulated S. pneumoniae Frequently, pneumococci and H. influenzae live together in the human nasopharynx, forming a self-produced biofilm. Biofilms present a global medical challenge since the inherent antibiotic resistance of their producers demands the use of large doses of antibiotics over prolonged periods. Frequently, these therapeutic measures fail, contributing to bacterial persistence. Here, we describe the development of an in vitro nonencapsulated S. pneumoniae-nontypeable H. influenzae biofilm system with polystyrene or glass-bottom plates. Confocal laser scanning microscopy and specific fluorescent labeling of pneumococcal cells with Helix pomatia agglutinin revealed an even distribution of both species within the biofilm. This simple and robust protocol of mixed biofilms was used to test the antimicrobial properties of two well-known antioxidants that are widely used in the clinical setting, i.e., N-acetyl-l-cysteine and cysteamine. This repurposing approach showed the high potency of N-acetyl-l-cysteine and cysteamine against mixed biofilms of nonencapsulated S. pneumoniae and nontypeable H. influenzae Decades of clinical use mean that these compounds are safe to use, which may accelerate their evaluation in humans.