Isolates Of Haemophilus Influenzae Research Articles

Bacteriological Tracing of Haemophilus influenzae in Some Public Toilet Seat Bowls of Port Harcourt

The study aimed at tracing Haemophilus influenzae on toilet seat bowls of some public toilets in Port Harcourt. The toilets were coded DER, TYU, AFR for park, market and hospital toilets respectively, for the purpose of the study. Swabs were collected aseptically from the toilet seat bowls, with a moistened swab stick, and then introduced into a freshly prepared sterile peptone water for viability of the Haemophilus influenza isolates. Thereafter, the spread plate technique was employed in which the swabbed samples were inoculated into Chocolate agar. Result showed toilet seat bowl coded DER had a Haemophilus influenzae mean count of 5 x 102CFU/ml while codes TYU and AFR had a mean Haemophilus influenzae counts of 6 x 102 and 9 x 102 CFU/ml respectively. A percentage frequency occurrence of Haemophilus influenzae on the toilet bowl showed DER coded toilets had 17% frequency of occurrence, while codes TYU and AFR had 25 and 58% frequency of occurrence respectively. A total of 49 isolates of Haemophilus influenzae were identified macroscopically and biochemically. The presence of Haemophilus influenzae on surface of toilet seat bowl may have resulted from aerosols generated during flushing. Thus, influenza infection (respiratory tract infection) may affect users. Hence, toilet seats, specifically, codes AFR class of toilets should be closed before and after flushing at all times.

Peritonitis Due to Haemophilus Influenzae in Peritoneal Dialysis: Report of An Exceptional Case

Case Description: 33-year-old woman with a history of end-stage renal disease on peritoneal dialysis, who came to the emergency department for abdominal pain of sudden onset associated with a change in the color of the peritoneal fluid. Clinical Findings: The patient had signs of systemic inflammatory response and generalized abdominal pain, with marked leukocyte response in peritoneal fluid cytochemistry. Treatment and Outcome: Empirical antibiotic treatment was started targeting the most prevalent microorganisms in abdominal infections associated with peritoneal dialysis, however with poor response to it and subsequent isolation of Haemophilus Influenzae for which antibiotherapy was modified with subsequent progressive clearance of peritoneal fluid and resolution of symptoms. Clinical Relevance: We describe the case of a patient on peritoneal dialysis who presented a bacterial peritonitis caused by H. Influenzae, an extremely infrequent germ in this type of infections. Although the presence of this germ is exceptional in peritoneal dialysis catheter-associated peritonitis, this microorganism should be ruled out in a patient with catheter-associated peritonitis that does not respond to the usual antibiotic therapy. To our knowledge only 8 cases have been reported in the literature and none in our setting.

Antibiotic resistance, bacterial transmission and improved prediction of bacterial infection in patients with antibody deficiency

Abstract Background Antibody-deficient patients are at high risk of respiratory tract infections. Many therefore receive antibiotic prophylaxis and have access to antibiotics for self-administration in the event of breakthrough infections, which may increase antimicrobial resistance (AMR). Objectives To understand AMR in the respiratory tract of patients with antibody deficiency. Methods Sputum samples were collected from antibody-deficient patients in a cross-sectional and prospective study; bacteriology culture, 16S rRNA profiling and PCR detecting macrolide resistance genes were performed. Bacterial isolates were identified using MALDI-TOF, antimicrobial susceptibility was determined by disc diffusion and WGS of selected isolates was done using Illumina NextSeq with analysis for resistome and potential cross-transmission. Neutrophil elastase was measured by a ProteaseTag immunoassay. Results Three hundred and forty-three bacterial isolates from sputum of 43 patients were tested. Macrolide and tetracycline resistance were common (82% and 35% of isolates). erm(B) and mef(A) were the most frequent determinants of macrolide resistance. WGS revealed viridans streptococci as the source of AMR genes, of which 23% also carried conjugative plasmids linked with AMR genes and other mobile genetic elements. Phylogenetic analysis of Haemophilus influenzae isolates suggested possible transmission between patients attending clinic. In the prospective study, a negative correlation between sputum neutrophil elastase concentration and Shannon entropy α-diversity (Spearman’s ρ = −0.306, P = 0.005) and a positive relationship with Berger–Parker dominance index (ρ = 0.502, P < 0.001) were found. Similar relationships were noted for the change in elastase concentration between consecutive samples, increases in elastase associating with reduced α-diversity. Conclusions Measures to limit antibiotic usage and spread of AMR should be implemented in immunodeficiency clinics. Sputum neutrophil elastase may be a useful marker to guide use of antibiotics for respiratory infection.

Determination of Antibiotic Resistance Pattern of Haemophilus influenzae Isolated from Egyptian Patients in Ain Shams University Hospitals

Abstract Background Haemophilus influenzae is small, non motile, non spore-forming, non acid fast, pleomorphic, gram negative bacilli with fastidious growth requirements. Cells in this genus are Cocobacilli or short rods. Haemophilus influenzae type b causes meningitis, epiglottitis, septicemia and osteomyelitis. Non-typeable H. influenzae is the cause of otitis media, sinusitis, pneumonia, and exacerbation in patients with COPD. The resistance to commonly used antibiotics has risen in recent years. Some of the main mechanisms of antimicrobial resistance of H. influenzae are those to β-lactam antibiotics. More frequent (in about 30%) is the plasmid-mediated production of β-lactamase of types TEM1 and ROB1, called β-lactamase positive ampicillin-resistant strains (BLPAR). In a small percentage of the ampicillin-nonsusceptible strains a change in penicillin-binding protein (PBP3) is detected, which reduces its affinity to penicillins and cephalosporins. PBP3 is a transpeptidase, which is encoded by the ftsI gene. Mutations in this gene lead to amino acid substitution in the transpeptidase domain of РВР3. These strains are called β-lactamase negative ampicillin resistant (BLNAR). Objective The aim of our study is 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. Materials and Methods The present study was conducted on fifty (50) different isolates of Haemophilus Influenzae isolated from different clinical specimens submitted to the Main Microbiology laboratory of Ain Shams University Hospitals. All isolates were subjected to subculture on chocolate agar, Phenotypic identification of colonies by routine methods, antibiotic susceptibility testing by using disk diffusion method according to Clinical and Laboratory Standard Institute recommendations (2019), and Multiplex PCR for detection of TEM & ROB genes. Results Susceptibility to Ampicillin was 12% (6/50) while 88% (44/50) were resistant to ampicillin. TEM gene was detected in 66% (33/50) while ROB gene was detected in 2% (1/50). 35.3% (6/17) isolates that were TEM negative were sensitive to ampicillin & 64.7% (11/17) isolates that were TEM negative were resistant to ampicllin. 100% (33/33) isolates that were TEM positive were resistant to ampicillin. Conclusions

Evaluation of in vitro activity of ceftaroline against pathogens associated with community-acquired pneumonia: ATLAS program 2017–2019

Ceftaroline is an important therapeutic option for community-acquired pneumonia (CAP). Antimicrobial susceptibility to ceftaroline and other antimicrobial agents against Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilusinfluenzae isolates collected worldwide from identified respiratory tract sources is reported by age groups (0-18, 19-65, and >65years). Antimicrobial susceptibility of isolates, collected as part of the ATLAS program (2017-2019), was performed per EUCAST/CLSI guidelines. S. aureus (N=7103; methicillin-susceptible S. aureus [MSSA]=4203; methicillin-resistant S. aureus [MRSA]=2791), S. pneumoniae (N=4823; EUCAST/CLSI, penicillin-intermediate S. pneumoniae [PISP]=1408/870; penicillin-resistant S. pneumoniae [PRSP]=455/993), and H. influenzae (N=3850; β-lactamase [βL]-negative=3097; βL-positive=753) isolates were collected from respiratory tract specimens. Susceptibility to ceftaroline was 89.08%-97.83% for S. aureus, 99.95%-100% for MSSA, and 78.07%-92.74% for MRSA isolates across age groups; S. aureus as well as MRSA isolates derived from the 0-18 years age group demonstrated the highest susceptibility rates to ceftaroline. Susceptibility to ceftaroline was 98.25%-99.77% for S.pneumoniae, 99.74%-100% for PISP, and 86.23%-99.04% for PRSP isolates across age groups. Across all age groups, susceptibility to ceftaroline was 89.53%-99.70% for H.influenzae, 93.02%-100% for βL-negative, and 77.78%-98.35% for βL-positive isolates. Irrespective of age, susceptibility to ceftaroline was high among the majority of S. aureus, S. pneumoniae, and H. influenzae isolates collected in this study.

A Significant Role of Nontypeable Haemophilus influenzae in Acute Otitis Media in Bulgarian Children

Abstract Objective We conducted a study on Haemophilus influenzae isolates recovered from children with acute otitis media (AOM). We aimed to establish the distribution of noncapsulated (also known as nontypeable Haemophilus influenzae [NTHi]) and encapsulated H. influenzae in the study population, and the antimicrobial susceptibilities of the isolates. Methods We collected 113 nasopharyngeal swabs and 91 middle ear fluids/otorrhea specimens from patients up to 9 years of age with AOM. Of these, 26.1% (n = 53) were culture-positive for H. influenzae. Only one episode of AOM was included per patient. Conventional tests and rapid panel Neisseria/Haemophilus panel were used for the identification of the isolates. Detection of encapsulated and noncapsulated strains was done by polymerase chain reaction (PCR) for bexA gene. PCR-serotyping was performed for capsule types: “a” and “f.” Biotypes were assigned based on the indole, urease, and ornithine decarboxylase activity. Susceptibility testing was performed according to the criteria of European Committee on Antimicrobial Susceptibility Testing (EUCAST). Results Capsule determination showed that 96.2% of H. influenzae isolates responsible for “mild” and “severe” AOM cases in children were NTHi. Biotype I was predominantly associated with AOM isolates. Capsule types “a” and “c” were found in two isolates. Antibiotic resistance was found in 39.6% of the isolates. The highest resistance rate was for trimethoprim-sulfamethoxazole (37.7%). About 20.7% of isolates were ampicillin-resistant: 5.6% expressed a β-lactamase, and 15.1% had a β–lactamase-negative ampicillin-resistant phenotype. Conclusion The current prevalence rates of nonsusceptible H. influenzae to ampicillin appear to be low among AOM. NTHi is an emergent pathogen in AOM cases. Ongoing observations are needed about how NTHi colonizes, survives, and evolves into a leading causative agent of H. influenzae diseases.

Respiratory culture organism isolation and test characteristics in children with tracheostomies with and without acute respiratory infection.

Among children with tracheostomies, little is known about how respiratory culture results differ between states with and without acute respiratory infections (ARI), or the overall test performance of respiratory cultures. To determine the association of respiratory culture organism isolation with diagnosis of ARI in children with tracheostomies, and assess test characteristics of respiratory cultures in the diagnosis of bacterial ARI (bARI). This single-center, retrospective cohort study included respiratory cultures of children with tracheostomies obtained between 2010 and 2018. The primary predictor was ARI diagnosis code at the time of culture; the primary outcomes were respiratory culture organism isolation and species identified. Generalized estimating equations were used to assess for association between ARI diagnosis and isolation of any organism while controlling for potential confounders and accounting for within-patient clustering. A multinomial logistic regression equation assessed for association with specific species. Test characteristics were calculated using bARI diagnosis as the reference standard. Among 3578 respiratory cultures from 533 children (median 4 cultures/child, interquartile range (IQR): 1-9), 25.9% were obtained during ARI and 17.2% had ≥1 organism. Children with ARI diagnosis had higher odds of organism identification (adjusted odds ratio 1.29, 95% confidence interval [CI] 1.16-1.44). When controlling for covariates, ARI was associated with isolation of Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, and Streptococcus pyogenes. Test characteristics revealed a 24.3% sensitivity, 85.2% specificity, 36.5% positive predictive value, and 76.3% negative predictive value in screening for bARI. The utility of respiratory culture testing to screen for, diagnose, and direct treatment of ARI in children with tracheostomies is limited.

In vitro activity of cefpodoxime against Russian clinical isolates of Haemophilus influenzae, Streptococcus pneumoniae and Streptococcus pyogenes

Objective. To determine in vitro activity of oral III generation cephalosporin cefpodoxime against clinical isolates of Haemophilus influenzae, Streptococcus pneumoniae and Streptococcus pyogenes isolated from patients with community-acquired respiratory tract infections in different regions of the Russian Federation. Materials and Methods. The study included isolates of bacterial pathogens of community-acquired respiratory tract infections isolated from outpatients and hospitalized patients in different regions of the Russian Federation. A total of 558 isolates were included in the study, including 184 isolates of H. influenzae, 186 isolates of S. pneumoniae and 188 isolates of S. pyogenes. Species identification was performed using the MALDI-TOF mass spectrometry (Bruker Daltonics, Germany), for S. pneumoniae identification was also performed taking into account the morphology of colonies on blood agar, the presence of α-hemolysis, negative catalase reaction, sensitivity to optochin and positive results of latex-agglutination using DrySpot kit (OXOID, UK). Antimicrobial susceptibility to cefpodoxime and comparative antimicrobials was determined using broth microdilution method; interpretation of susceptibility testing results was performed in accordance with the recommendations of EUCAST, v.13.0. Data analysis and visualization were performed using the online platform AMRcloud. Results. Despite the generally low incidence of antibiotic resistance in the tested H. influenzae isolates, cefpodoxime, to which all tested isolates were susceptible, was superior to all other oral antibiotics in terms of in vitro activity: aminophenocillins (R – 8.7%), amoxicillin/clavulanate (R – 1.1%), co-trimoxazole (R – 31.5%), levofloxacin (R – 3.8%), moxifloxacin (R – 3.8%), tetracycline (R – 11%), cefixime (R – 2.2%), ceftibuten (R – 3.3%). Among the studied S. pneumoniae isolates, 81.7% were susceptible to cefpodoxime. All isolates resistant to penicillin, amoxicillin and ceftriaxone were also resistant to cefpodoxime. Cefpodoxime was inferior to levofloxacin (R – 0%), moxifloxacin (R – 0%), linezolid (R – 0%), vancomycin (R – 0%), ertapenem (R – 8.6%), ceftaroline (R – 2.3%), and chloramphenicol (R – 3.2%) in terms of in vitro activity against S. pneumoniae. However, all these drugs are either not available in oral form or have a less favorable safety profile compared to cefpodoxime. When compared with other III generation oral cephalosporins cefixime and ceftibuten, the activity of cefpodoxime against S. pneumoniae was significantly higher based on MIC50/90 values (cefixime – 0.125⁄8 mg/l, ceftibuten – 2/≥ 128 mg/l, cefpodoxime – 0.06/4 mg/l) and MICs range (cefixime – 0.06/≥ 128 mg/l, ceftibuten – 0.06/≥ 128 mg/l, cefpodoxime – 0.03/32 mg/l). No strains resistant to β-lactam antibiotics were detected among the tested S. pyogenes isolates. Based on the MIC50/90 values and the range of MIC values, the in vitro activity of cefpodoxime was higher than that of ceftibuten and comparable to that of cefixime. Conclusions. According to the results of our study, as well as in view of its pharmacokinetic profile, high safety and compliance, cefpodoxime can be considered as one of the options for oral therapy of community-acquired bacterial upper and lower respiratory tract infections.

Antibiotic susceptibility profiles of Haemophilus influenzae isolates collected in Dakar between 2018 and 2022

Antibiotic susceptibility profiles of Haemophilus influenzae isolates collected in Dakar between 2018 and 2022

Detection of the Inhibition Activity of Alcoholic Extract of Green Tea Leaves (Camellia sinensis) and Zinc Oxide Nanoparticles Against Few Bacteria and Fungi Species Isolated from Eyes Infection

A 80 samples were collected from patients who were suffering from eyes infections in Samarra hospitals, Samarra city during the period from December 20, 2020 to January 20, 2021. All the samples were from male and female aged between 1–75 years. They were cultivated on selective and differential media in the laboratory and stained by gram stain. Some biochemical tests were done as confirmation diagnostic tests. There were 71 (88.75%) samples yielded positive growth that includes Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pneumonia 24 (30%), 16 (20%) and 9 (11.25%), respectively. The results show that 7 isolates of Haemophilus Influenzae, 6 isolates of Pseudomonas aeruginosa, 5 isolates of Escherichia coli with percentages (11.25%), (7.5%) and (6.25%) respectively. Four isolates with 5% of Candida albicans were isolated from eyes infections. The sensitivity of bacterial isolates was tested using 12 antibiotics that included quinolones, aminoglycosides, beta- lactams and tetracyclines antibiotics. Imipenem and levofloxacin were more effective than the rest of the antibiotics which range from medium to inactive. The antibacterial impact of alcoholic extracts of Camellia sinensis leaves and zinc oxide nanoparticles (ZnO NPs) on certain microbial infections were investigated. Results show that 100% concentration of alcoholic extract gives a high inhibitory effect on all isolated microbes in compares with NPs. The highest inhibition zone is S. aureus with a diameter of 35 mm and the less is 10 mm against S. pneumoniae. The alcoholic extract shows an effective result against C. albicans with a diameter of 15mm. At concentrations of 100% and 150%, zinc oxide nanoparticles inhibit S. aureus, E. coli, and C. albicans, respectively.

Impact of bacterial strain acquisition in the lung of patients with COPD: the AERIS study

Background Bacterial infections are associated with acute exacerbations of chronic obstructive pulmonary disease (AECOPD), but the mechanism is incompletely understood. Method In a COPD observational study (NCT01360398), sputum samples were collected monthly at the stable state and exacerbation. Post-hoc analyses of 1307 non-typeable Haemophilus influenzae (NTHi) isolates from 20 patients and 756 Moraxella catarrhalis isolates from 38 patients in one year of follow-up were conducted by multilocus sequence typing (MLST). All isolates came from cultured sputum samples that were analyzed for bacterial species presence, apparition (infection not detected at the preceding visit), or acquisition (first-time infection), with the first study visit as a baseline. Strain apparition or new strain acquisition was analyzed by MLST. The odds ratio (OR) of experiencing an exacerbation vs. stable state was estimated by conditional logistic regression modelling, stratified by patient. Results The culture results confirmed a significant association with exacerbation only for NTHi species presence (OR 2.28; 95% confidence interval [CI]: 1.12–4.64) and strain apparition (OR 2.38; 95% CI: 1.08–5.27). For M. catarrhalis, although confidence intervals overlapped, the association with exacerbation for first-time species acquisition (OR 5.99; 2.75–13.02) appeared stronger than species presence (OR 3.67; 2.10–6.40), new strain acquisition (OR 2.94; 1.43–6.04), species apparition (OR 4.18; 2.29–7.63), and strain apparition (OR 2.78; 1.42–5.42). This may suggest that previous M. catarrhalis colonization may modify the risk of exacerbation associated with M. catarrhalis infection. Conclusions The results confirm that NTHi and M. catarrhalis infections are associated with AECOPD but suggest different dynamic mechanisms in triggering exacerbations.

Isolation and Antimicrobial Susceptibility Testing of Haemophilus influenzae in a Tertiary Care Hospital, a 6-Year Study (2016 to 2021)

Objective: To determine the prevalence and antimicrobial susceptibility of Haemophilus influenzae at Taksin Hospital. Materials and Methods: The susceptibilities of clinical isolates to six antimicrobial agents, ampicillin (AP), cefuroxime (CXM), cefotaxime (CTX), ciprofloxacin (CIP), trimethoprim-sulfamethoxazole (SXT), and meropenem (MEM), between 2016 and 2021 were evaluated by the standard disk diffusion method. Results: One hundred thirty-eight H. influenzae clinical isolates were found in different patients. There were 63.04% male patients. The ages of patients ranged from two months to 93 years old (mean±SD: 65.67±20.58). H. influenzae was mostly found in patients older than 50 (60.14%) years old. In children, H. influenzae was mostly found in patients younger than 1 to 10 (16.67%) years old. Unduplicated H. influenzae from different patients were isolated from the sputum (71.01%), blood (11.59%), pus from eyes (10.14%), and urethra (2.90%). H. influenzae demonstrated 100% susceptibility to CTX, CIP, and MEM, but less susceptibility to CXM (93.48%), AP (49.28%), and SXT (53.62%). Conclusion: The present study results suggested the importance of monitoring the prevalence of H. influenzae at a hospital in Bangkok. The antibiogram of susceptibility helps provide guidelines for clinician to consider empirical treatment. Keywords: Haemophilus influenzae; Drug resistance, Thailand

Risk Factors and Relation with Mortality of a New Acquisition and Persistence of Pseudomonas aeruginosa in COPD Patients

The isolation of Pseudomonas aeruginosa (PA) in patients with chronic obstructive pulmonary disease (COPD) is associated with increased mortality. Yet, factors associated with first PA sputum isolation, and PA persistence have not been investigated before. The objective of the present study was to investigate risk factors for new acquisition and persistence of PA infection and their relationship with all-cause mortality in patients with COPD. Post-hoc analysis of prospectively collected cohort of 170 COPD patients (GOLD II-IV) who were free of previous PA isolation and followed up every 3-6 months for 85 [50.25-110.25] months. PA was isolated for the first time in 41 patients (24.1%) after 36 [12-60] months of follow-up. Risk factor for first PA isolation were high cumulative smoking exposure, severe airflow limitation, previous severe exacerbations, high fibrinogen levels and previous isolation of Haemophilus Influenzae. PA was isolated again one or more times during follow-up in 58.5% of these patients. This was significantly associated with the presence of CT bronchiectasis and persistence of severe exacerbations, whereas the use of inhaled antibiotic treatment after the first PA isolation (at the discretion of the attending physician) reduced PA persistence. During follow-up, 79 patients (46.4%) died. A single PA isolation did not increase mortality, but PA persistence did (HR 3.06 [1.8-5.2], p = 0.001). We conclude that PA occurs frequently in clinically stable COPD patients, risk factors for a first PA isolation and PA persistence are different, and the latter (but not the former) is associated with increased all-cause mortality.

Evaluation of a Multiplex PCR Panel for the Microbiological Diagnosis of Pneumonia in Hospitalized Patients: Experience from an Academic Medical Center

ObjectivesWe evaluated the value of BioFire® FilmArray® pneumonia panel in establishing a microbiological diagnosis of pneumonia. We evaluated opportunities for antimicrobial optimization from its use. MethodsWe included adult patients with pneumonia between May 2019 and January 2020. The pneumonia panel was used on high-quality sputum specimens, and the results were prospectively compared with sputum cultures and other tests performed according to standard of care. ResultsSeventy patients were included, sixty-nine of whom completed a 5-day antimicrobial course for pneumonia, and 14.3% died during hospitalization. There was a trend of higher rate of microbiological diagnosis among the patients with culture submitted before antimicrobial administration (9/15 vs. 20/55; p = 0.09). The panel increased the microbiological diagnosis from 29/70 to 59/70 (p < 0.001) patients. The per isolate analysis revealed an increase in the isolation of Haemophilus influenzae (p = 0.002) and Streptococcus pneumoniae (p = 0.05). On review of empiric antimicrobials, there was potential for antimicrobial optimization in 56/70 patients, including 9 bacteria among 9 patients, which were not covered by empiric treatment and another 70 antimicrobials in 49 patients that could have been stopped. ConclusionsIncorporation of the pneumonia panel in the diagnostic work-up of pneumonia substantially increased the rate of microbiological diagnosis and revealed abundant opportunities for antimicrobial optimization.

In vitro activity of thiamphenicol against Haemophilus influenzae, Streptococcus pneumoniae and Streptococcus pyogenes clinical isolates

Objective. To determine in vitro activity of thiamphenicol and other clinically available antimicrobials against clinical isolates of Haemophilus influenzae, Streptococcus pneumoniae and Streptococcus pyogenes. Materials and Methods. We included in the study 875 clinical isolates from 20 Russian cities during 2018–2019. Among tested strains, 126 were H. influenzae, 389 – S. pneumoniae, 360 – S. pyogenes. Antimicrobial susceptibility testing was performed using broth microdilution method according to ISO 20776-1:2006. AST results were interpreted according to EUCAST v.11.0 clinical breakpoints. Results. The minimum inhibitory concentrations (MICs) of thiamphenicol did not exceed 2 mg/L for 94.4% of H. influenzae strains (MIC50 and MIC90 were 0.5 and 1 mg/L, respectively). Thiamphenicol was active against 76.9% of ampicillin-resistant H. influenzae strains (MIC of thiamphenicol &lt; 2 mg/L). The MIC of thiamphenicol was in the range of 0.06–2 mg/L for 96.7% of S. pneumoniae strains (MIC50 and MIC90 were 0.5 and 2 mg/L, respectively). The MIC of thiamphenicol for 90.6% of S. pneumoniae strains with reduced susceptibility to penicillin (MIC of penicillin &gt; 0.06 mg/L) did not exceed 2 mg/L. A total of 88.1% of S. pneumoniae strains resistant to erythromycin were highly susceptible to thiamphenicol (MIC &lt; 2 mg/L). The MIC of thiamphenicol did not exceed 8 mg/L for 96.1% of S. pyogenes strains (MIC50 and MIC90 were 2 and 4 mg/L, respectively). Conclusions. Thiamphenicol was characterized by relatively high in vitro activity, comparable to that of chloramphenicol, against tested strains of H. influenzae, S. pneumoniae and S. pyogenes, including S. pneumoniae isolates with reduced susceptibility to penicillin.

1253. In Vitro Activity of Omadacycline against 7000 Bacterial Pathogens from the United States Stratified by Infection Type (2019)

BackgroundOmadacycline (OMC) is a new aminomethylcycline antibacterial drug belonging to the tetracycline class, for intravenous or oral administration. It is well tolerated and has proven effective in the treatment of a variety of bacterial infections. OMC is active against bacterial strains expressing the most common clinically relevant tetracycline resistance mechanisms, namely efflux and ribosomal protection.Methods7,000 clinical isolates were collected during 2019 in the SENTRY Surveillance Program from 31 medical centers in the United States (US). Isolates were obtained from bloodstream infection (23.8%), skin and skin structure infection (21.6%), pneumonia in hospitalized patients (22.7%), urinary tract infection (14.5%), intraabdominal infection (6.2%), community acquired respiratory tract infection (10.3%) and other infection types (0.9%). Identifications were confirmed by MALDI-TOF. One isolate/patient/infection episode was tested. Broth microdilution susceptibility testing was conducted according to CLSI M07 (2018) and M100 (2020) guidelines. Results were interpreted using US FDA and CLSI breakpoint criteria.ResultsOMC demonstrated potent in vitro activity against Staphylococcus aureus isolates representing multiple infection types (MIC90, 0.12-0.25 mg/L; 94.7%-99.0% susceptible [S]) including MRSA (MIC90, 0.25 mg/L; 96.5% S) (Table). All S. lugdunensis (MIC90, 0.06 mg/L), Enterococcus faecalis (MIC90, 0.12-0.25 mg/L), and Haemophilus influenzae (MIC90, 1 mg/L) isolates were S to OMC. OMC was active against Streptococcus pyogenes isolates from SSSI (MIC90, 0.12 mg/L; 93.3%-98.5%S) including macrolide-resistant (R) strains. Similarly, S. pneumoniae isolates from RTI were S to OMC (MIC90, 0.06-0.12 mg/L; 98.8%-100%S) regardless of resistance to tetracycline or penicillin. Overall, 90.2%-93.6% of Enterobacter cloacae (MIC90, 4 mg/L) and 89.7%-94.7% of Klebsiella pneumoniae (MIC90, 4-8 mg/L) isolates from multiple infection types were S to OMC.ConclusionOMC demonstrated potent in vitro activity against Gram-positive and -negative bacterial pathogens from multiple infection types including SSSI and RTI and isolates displaying resistance to tetracycline, macrolides, and penicillin.Table 1 DisclosuresMichael A. Pfaller, MD, Amplyx Pharmaceuticals (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Helio S. Sader, MD, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Melinta (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support) Mariana Castanheira, PhD, 1928 Diagnostics (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Allergan (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cidara Therapeutics (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Cipla Ltd. (Research Grant or Support)Fox Chase Chemical Diversity Center (Research Grant or Support)GlaxoSmithKline (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Merck (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Merck & Co, Inc. (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support)Pfizer (Research Grant or Support)Qpex Biopharma (Research Grant or Support)

Draft Genome Sequence of an Isolate of Nontypeable Haemophilus influenzae from an Acute Exacerbation of Chronic Obstructive Pulmonary Disease in Tasmania.

Nontypeable Haemophilus influenzae (NTHi) is an important cause of human illness, including pneumonia and acute exacerbations of chronic obstructive pulmonary disease (COPD). We report here the draft genome of an isolate of NTHi collected from the sputum of a patient presenting with COPD in Tasmania, Australia.

Antimicrobial Activity of Ceftolozane-Tazobactam and Comparators against Clinical Isolates of Haemophilus influenzae from the United States and Europe.

Nine hundred Haemophilus influenzae clinical isolates from 83 U.S. and European medical centers were tested for susceptibility by reference broth microdilution methods against ceftolozane-tazobactam and comparators. Results were stratified by β-lactamase production and infection type. Overall, ceftolozane-tazobactam MIC50/90 values were 0.12/0.25 mg/liter, and 99.0% of isolates were inhibited at the susceptible breakpoint of ≤0.5 mg/liter; the highest MIC value was only 2 mg/liter. Our results support using ceftolozane-tazobactam to treat H. influenzae infections.

Widespread of non-typeable Haemophilus influenzae with high genetic diversity after two decades use of Hib vaccine in China.

BackgroundThe aim of this study was to analyze the microbiological characteristics of nasopharyngeal carriage Haemophilus influenzae isolates collected from children with respiratory infections in Beijing hospital and Youyang Hospital of China.MethodsThe serotypes of all isolates were determined using latex agglutinated antisera (a‐f). The minimum inhibitory concentrations (MICs) of 11 antibiotics were determined using E‐test strips. For the beta‐lactamase‐negative ampicillin‐resistant (BLNAR) isolates, ftsI gene was sequenced based on fragments amplified by PCR. STs of H influenzae isolates were determined by multi‐locus sequence typing.ResultsThe overall carriage rate of H influenzae in the study population was 9.1% (362/3984). One hundred and ninety H influenzae isolates which were selected in our study were non‐typeable (NTHi) and 44 (23.2%) of them were positive for β‐lactamase. All isolates were susceptible to ceftriaxone and levofloxacin. Susceptibility rates to erythromycin and sulfamethoxazole‐trimethoprim in Beijing were significantly higher than Youyang (P < .05). Thirty‐six BLNAR isolates were identified. The MLST analysis showed 108 STs in 190 isolates, the most common of which were ST408 (11, 5.8%), ST914 (10, 5.3%), ST57 (9, 4.7%), and ST834 (6, 3.2%). Twelve STs were detected in both of the study sites, which covered 63 isolates.ConclusionsAll isolates in the present study were NTHi, which suggested widespread of this type in China. The BLNAR isolates were detected more frequently than before. Because high genetic diversity of NTHi isolates of H influenzae exists worldwide, it is important to continuously monitor these bacteria in the future.

In Vitro Investigation of the Antibacterial Activity of Nigella sativa Oil on Some of the Most Commonly Isolated Bacteria in Otitis Media and Externa

This study aimed to evaluate the antibacterial efficacy of Nigella sativa (NS) seed oil against the most frequently isolated infectious bacteria of the middle and external ear. The in vitro antibacterial activity of NS oil was evaluated against 34 clinical isolates of Streptococcus pneumoniae, 32 clinical isolates of Moraxella catarrhalis, 32 clinical isolates of Haemophilus influenzae, and 32 clinical isolates of Pseudomonas aeruginosa. Staphylococcus aureus, Escherichia coli, and P. aeruginosa were also evaluated for their sensitivity to the NS oil. The minimum inhibitory concentration (MIC) of the NS oil was determined via a broth dilution technique. Serial solutions were prepared in a Mueller Hinton-F broth to achieve an ultimate concentration of NS oil within the microplate wells ranging from 256 μg/mL to 0.25 μg/mL. The growth control wells and medium were used for each bacterial strain, and the microplates were incubated at 35°C for 24 h. Those wells having no visible growth and the lowest concentration of NS oil were accepted as showing the MIC. In this study, a comparison was made between NS oil and the various antibiotics known to be effective against the bacterial strains mentioned above. The NS was shown to have bactericidal activity against H. influenzae, M. catarrhalis, and S. pneumoniae. However, the NS was not found to be effective against P. aeruginosa at any concentration. The results of this laboratory-based study support the use of NS oil as an alternative treatment for ear infections. However, it is necessary to conduct clinical studies to evaluate the antibacterial efficacy of NS oil on patients with ear infections.