Antimicrobial Susceptibility/Resistance of Streptococcus Pneumoniae

Inorganic catalase-powered nanomotors with hyaluronic acid coating for pneumonia therapy

Clinical therapy for widespread infections caused by Streptococcus pneumoniae (S. pneumoniae), such as community-acquired pneumonia, is highly challenging. As an important bacterial toxin, hydrogen peroxide (H2O2) secreted by S. pneumoniae can suppress the host's immune system and cause more severe disease. To address this problem, a hyaluronic acid (HA)-coated inorganic catalase-driven Janus nanomotor was developed, which can cleverly utilize and decompose H2O2 to reduce the burden of bacterial infection, and have excellent drug loading capacity. HA coating prevents rapid leakage of loaded antibiotics and improves the biocompatibility of the nanomaterials. The Janus nanomotor converted H2O2 into oxygen (O2), gave itself the capacity to move actively, and encouraged widespread dispersion in the lesion site. Encouragingly, animal experiments demonstrated that the capability of the nanomotors to degrade H2O2 contributes to diminishing the proliferation of S. pneumoniae and lung tissue damage. This self-propelled drug delivery platform provides a new therapeutic strategy for infections with toxin-secreting bacteria.

Detection of Macrolide-Resistant Streptococcus pneumoniae Genes and Its Clinical Outcomes in a Tertiary Teaching Hospital in Malaysia

Background

Streptococcus pneumoniae is one of the leading causes of mortality and morbidity worldwide. The dramatic increase in in-vitro resistance of antimicrobial agents, particularly beta-lactams and macrolides, makes pneumococcal infections difficult to treat. The aim of this study was to describe the drug resistance rate, assess the prevalence of macrolide-resistant genes and review the clinical complications of pneumococcal infections among patients presented to Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia.

Methods

This is a descriptive cross-sectional study. All S. pneumoniae isolates collected from clinical specimens within a 1-year period were subjected to selected antimicrobial susceptibility testing using E-test strips. Polymerase chain reaction (PCR) analysis was conducted to detect macrolide-resistant determinants. The patient's clinical data were obtained from clinical notes.

Results

A total of 113 patients with a positive growth of S. pneumoniae were included in the study. The most common predisposing factors among them were bronchopulmonary diseases (15.9%). The penicillin-resistant rate was 7.1%, with minimal inhibitory concentration (MIC) ranging between 0.012 μg/mL and >32 μg/mL, and the erythromycin-resistant rate was 26.5%, with a MIC range of 0.03 μg/mL-> 256 μg/mL. Most of the erythromycin-resistant isolates were found to have the mef(A) gene (50.4%) and the erm(B) gene (20%); 16.7% had a combination of genes mef(A) and erm(B), and 13.3% had none of the two genes. Community-acquired pneumonia is the predominant type of pneumococcal infection. There was no significant association between the presence of macrolide resistance determinants and mortality (P = 0.837) or complications (P > 0.999 for empyema and cardiac complication; P = 0.135 for subdural abscess).

Conclusion

The majority of erythromycin-resistant isolates were found to have the mef(A) gene, followed by the erm(B) gene and a combination of genes mef(A) and erm(B).

Antibiotic resistance in ocular bacterial infections: an integrative review of ophthalmic chloramphenicol

INTRODUCTION

Chloramphenicol is a broad-spectrum antibiotic widely used for treating ophthalmic infections, but concerns about rising bacterial resistance to chloramphenicol have been observed due to its frequent use as an over-the-counter medication. This review assessed the common ophthalmic bacterial pathogens, their chloramphenicol resistance mechanisms, and rates of drug resistance.

METHODS

PubMed and Google Scholar databases were searched for relevant publications from the years 2000 to 2022, bordering on ophthalmic bacterial infections, chloramphenicol susceptibility profiles, and drug resistance mechanisms against chloramphenicol. A total of 53 journal publications met the inclusion criteria, with data on the antibiotic susceptibility profiles available in 44 of the reviewed studies, which were extracted and analyzed.

RESULTS

The mean resistance rates to chloramphenicol from antibiotic susceptibility profiles varied between 0% and 74.1%, with the majority of the studies (86.4%) showing chloramphenicol resistance rates below 50%, and more than half (23 out of 44) of the studies showed resistance rates lower than 20%. The majority of the publications (n = 27; 61.4%) were from developed nations, compared to developing nations (n = 14; 31.8%), while a fraction (n = 3; 6.8%) of the studies were regional cohort studies in Europe, with no country-specific drug resistance rates. No pattern of cumulative increase or decrease in ophthalmic bacterial resistance to chloramphenicol was observed.

CONCLUSIONS

Chloramphenicol is still active against ophthalmic bacterial infections and is suitable as a topical antibiotic for ophthalmic infections. However, concerns remain about the drug becoming unsuitable in the long run due to some proof of high drug resistance rates.

Dosing Regimen of Aditoprim and Sulfamethoxazole Combination for the Glaesserella parasuis Containing Resistance and Virulence Genes

Glaesserella parasuis (G. parasuis) causes Glasser’s disease in pigs and causes high mortality in piglets. The new drug Aditoprim (ADP) alone or combined with Sulfamethoxazole (SMZ) is one of the good choices for treating respiratory infections. The objective of this study was to recommend the optimal dosing regimen for the treatment of G. parasuis infection which contains resistance and virulence genes by ADP/SMZ compound through pharmacokinetics–pharmacodynamics (PK-PD) modeling. The whole genome of the virulent strain G. parasuis H78 was obtained and annotated by whole genome sequencing. The results show that G. parasuis H78 consists of a unilateral circular chromosome with prophages in the genome. The annotation results of G. parasuis H78 showed that the genome contained a large number of virulence-related genes and drug resistance-related genes. The in vitro PD study showed that the antibacterial effect of ADP/SMZ compound against G. parasuis was time-dependent, and AUC/MIC was selected as the PK-PD modeling parameter. The PK study showed that the content of ADP/SMZ compound in pulmonary epithelial lining fluid (PELF) was higher than plasma, and there were no significant differences in ADP and SMZ PK parameters between the healthy and infected group. The dose equation to calculate the optimal dosing regimen of ADP/SMZ compound administration for control of G. parasuis infection was 5/25 mg/kg b.w., intramuscular injection once a day for 3~5 consecutive days. The results of this study provide novel therapeutic options for the treatment of G. parasuis infection to decrease the prevalence and disease burden caused by G. parasuis.

Shionone-Targeted Pneumolysin to Ameliorate Acute Lung Injury Induced by Streptococcus pneumoniae In Vivo and In Vitro

Streptococcus pneumoniae (S. pneumoniae), as a Gram-positive bacterium, can cause severe bacterial pneumonia, and result in high morbidity and mortality in infected people. Meanwhile, isolated drug-resistant S. pneumoniae is growing, which raises concerns about strategies for combatting S. pneumoniae infection. To disturb S. pneumoniae pathogenicity and its drug-resistance, developing novel anti-infective strategies or compounds is urgent. In this study, the anti-infective effect of shionone was explored. A minimum inhibitory concentration (MIC) assay and growth curve determination were performed to evaluate the effect of the tetracyclic triterpenoid compound shionone against S. pneumoniae. Hemolysis tests, western blotting, oligomerization inhibition assays, and molecular docking were carried out to explore the anti-infective mechanism of shionone. Moreover, the protective effect of shionone was also confirmed in a mousepneumonia model. The results showed that the excellent hemolytic inhibitory activity of shionone was observed at less than 8 μg/mL. Meanwhile, shionone could disturb the oligomerization of pneumolysin (PLY) but did not interfere with PLY expression at less than 4 μg/mL. Molecular docking suggested that shionone targeted the ASP-59, ILE-60, THR-57, PHE-344, and ASN-346 amino acid sites to reduce S. pneumoniae pathogenicity. Furthermore, shionone alleviated lung histopathologic injury and decreased lung bacterial colonization in vivo. The above results showed that shionone could bind to the PLY active pocket under the concentrations of 8 μg/mL and neutralize PLY hemolysis activity to reduce S. pneumoniae pathogenicity in vitro and in vivo.

Colonization by Streptococcus pneumoniae among children in Porto Velho, Rondônia, Western Brazilian Amazon

Streptococcus pneumoniae is one of the primary pathogens that are associated with acute respiratory infections (ARI) that cause high rates of morbidity and mortality among children under five years of age in developed and developing countries. This study aimed to determine the prevalence of nasopharyngeal colonization, the antimicrobial resistance profile, and the capacity for biofilm formation by S. pneumoniae isolated from children aged 0-6 years with ARI throughout the Porto Velho-RO. A total of 660 swabs were collected from children with ARI. Molecular and biochemical tests were performed to characterize the isolates. The disk-difusion method and the E-test were used for antimicrobial sensitivity testing (TSA). Biofilm formation capacity was assessed using microtiter plate assays, and serotype detection was acheived using polymerase chain reaction (PCR) analyses. The colonization rate for S. pneumoniae was 8.9% (59/660) and exhibited a high prevalence in children under 23 months of age 64.4% (38/59). The observed serotypes were 9V and 19F with frequencies of 1.7% (1/59) and 13.6% (8/59), respectively. The antimicrobial susceptibility test revealed 100% (59/59) sensitivity to vancomycin. In contrast, trimethoprim and oxacillin exhibited high resistance rates of 76.3% (45/59) and 52.5% (31/59), respectively. Of the biofilm-forming isolates, 54.8% (23/42) possessed resistance to some antimicrobials. In this study, S. pneumoniae showed high rates of antimicrobial resistance and the ability to form biofilms, as these are factors that favor bacterial persistence and can cause serious damage to the host.

Early detection of drug-resistant Streptococcus pneumoniae and Haemophilus influenzae by quantitative flow cytometry

Early detection of drug resistance contributes to combating drug-resistant bacteria and improving patient outcomes. Microbial testing in the laboratory is essential for treating infectious diseases because it can provide critical information related to identifying pathogenic bacteria and their resistance profiles. Despite these clinical requirements, conventional phenotypic testing is time-consuming. Additionally, recent rapid drug resistance tests are not compatible with fastidious bacteria such as Streptococcus and Haemophilus species. In this study, we validated the feasibility of direct bacteria counting using highly sensitive quantitative flow cytometry. Furthermore, by combining flow cytometry and a nucleic acid intercalator, we constructed a highly sensitive method for counting viable fastidious bacteria. These are inherently difficult to measure due to interfering substances from nutrients contained in the medium. Based on the conventional broth microdilution method, our method acquired a few microliter samples in a time series from the same microplate well to exclude the growth curve inconsistency between the samples. Fluorescent staining and flow cytometry measurements were completed within 10 min. Therefore, this approach enabled us to determine antimicrobial resistance for these bacteria within a few hours. Highly sensitive quantitative flow cytometry presents a novel avenue for conducting rapid antimicrobial susceptibility tests.

Signs and symptoms do not predict, but may help rule out acute Q fever in favour of other respiratory tract infections, and reduce antibiotics overuse in primary care

Background

From early 2009, the Dutch region of South Limburg experienced a massive outbreak of Q fever, overlapping with the influenza A(H1N1)pdm09 pandemic during the second half of the year and affecting approximately 2.9% of a 300,000 population. Acute Q fever shares clinical features with other respiratory conditions. Most symptomatic acute infections are characterized by mild symptoms, or an isolated febrile syndrome. Pneumonia was present in a majority of hospitalized patients during the Dutch 2007–2010 Q fever epidemic. Early empiric doxycycline, guided by signs and symptoms and patient history, should not be delayed awaiting laboratory confirmation, as it may shorten disease and prevent progression to focalized persistent Q fever. We assessed signs’ and symptoms’ association with acute Q fever to guide early empiric treatment in primary care patients.

Methods

In response to the outbreak, regional primary care physicians and hospital-based medical specialists tested a total of 1218 subjects for Q fever. Testing activity was bimodal, a first “wave” lasting from March to December 2009, followed by a second “wave” which lasted into 2010 and coincided with peak pandemic influenza activity. We approached all 253 notified acute Q fever cases and a random sample of 457 Q fever negative individuals for signs and symptoms of disease. Using data from 140/229(61.1%) Q fever positive and 194/391(49.6%) Q fever negative respondents from wave 1, we built symptom-based models predictive of Q-fever outcome, validated against subsets of data from wave 1 and wave 2.

Results

Our models had poor to moderate AUC scores (0.68 to 0.72%), with low positive (4.6–8.3%), but high negative predictive values (91.7–99.5%). Male sex, fever, and pneumonia were strong positive predictors, while cough was a strong negative predictor of acute Q fever in these models.

Conclusion

Whereas signs and symptoms of disease do not appear to predict acute Q fever, they may help rule it out in favour of other respiratory conditions, prompting a delayed or non-prescribing approach instead of early empiric doxycycline in primary care patients with non-severe presentations. Signs and symptoms thus may help reduce the overuse of antibiotics in primary care during and following outbreaks of Q fever.

Antimicrobial resistance: Call for rational antibiotics practice in India

It is a well-known fact that microorganisms are developing resistance to antimicrobial drugs present in the market that is known as antimicrobial resistance (AMR). This resistance in microbes is a great matter of concern among the scientific fraternity. This review article focuses on antibiotics and their respective resistant microbes, factors that cause resistance among microbes, and consequences of AMR at global as well as Indian scenario. This article would be a helpful resource in nutshell for making the ground for discovery of new antibiotics that will be more effective toward microbes.

Bacteriological profiles and drug susceptibility of Streptococcus isolated from conjunctival sac of healthy children

BACKGROUND

To investigate bacterial flora and antibiotics susceptibility of Streptococcus pneumoniae isolated from the conjunctival sac of heathy children.

METHODS

Bacteria were isolated from the secretions of conjunctival sac of healthy children between 2015 and 2018. Antimicrobial susceptibility of isolated S. pneumoniae strains were determined using microbroth dilution method.

RESULTS

The sac secretions were collected from a total of 6440 children. 1409 samples presented bacterial growth, accounting for 21.8% of the samples. Among the 22 bacterial species isolated, 528 samples presented Gram-positive Staphylococcus spp. growth, accounting for 37.4% of the isolates, followed by Corynebacterium spp., counting for 30% of the isolates and Streptococcus pneumoniae, counting for 21.4% of the isolates. Antibiotics susceptibility tests showed that the majority of S. pneumoniae isolates were sensitive to most antibiotics tested. However, 72.8 and 81.2% of the isolates were resistant to erythromycin and tetracycline, respectively, and over 10% of them were resistant to gentamicin, tobramycin and rifampicin.

CONCLUSIONS

The bacterial flora of healthy children is mainly consisted of Gram-positive bacteria belonging to Corynebacterium spp. and Streptococcus spp.; most of S. pneumoniae isolates were sensitive to antibiotics except erythromycin and tetracycline.

Invasive pneumococcal disease in hospitalised children from Lima, Peru before and after introduction of the 7-valent conjugated vaccine

The objective of this study was to determine the serotype distribution and antibiotic resistance of invasive pneumococcal disease (IPD) strains in children from Lima, Peru, before and after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7), which was introduced in the national immunisation program on 2009. We conducted a prospective, multicentre, passive surveillance IPD study during 2006-2008 and 2009-2011, before and right after the introduction of PCV7 in Peru. The study was performed in 11 hospitals and five private laboratories in Lima, Peru, in patients <18 years old, with sterile site cultures yielding Streptococcus pneumoniae. In total 159 S. pneumoniae isolates were recovered. There was a decrease in the incidence of IPD in children <2 years old after the introduction of PCV7 (18.4/100 000 vs. 5.1/100 000, P = 0.004). Meningitis cases decreased significantly in the second period (P = 0.036) as well as the overall case fatality rate (P = 0.025), including a decreased case fatality rate of pneumonia (16.3% to 0%, P = 0.04). PCV7 serotypes showed a downward trend. Vaccine-preventable serotypes caused 78.9% of IPD cases, mainly 14, 6B, 5, 19F and 23F. A non-significant increase in erythromycin resistance was reported. Our findings suggest that the introduction of PCV7 led to a significant decrease of IPD in children under 2 years old and in the overall case fatality rate.

Evaluation of Preclinical and Clinical Studies Published in Medical Journals of Bosnia and Herzegovina: Methodology Issues

INTRODUCTION

Results of preclinical and clinical studies in medicine could be trusted only if their design and statistical analysis were appropriate.

AIM

The aim of our study was to investigate whether preclinical and clinical studies published in medical journals of Bosnia and Herzegovina satisfy basic requirements for appropriate design and statistical interpretation of data.

METHODS

Preclinical and clinical studies published in medical journals of Bosnia and Herzegovina were retrieved from the PubMed database, and the sample for analysis was randomly chosen from the retrieved publications. Implementation rate of basic principles of experimental design (local control, randomization and replication) and rate of the most common errors in design of clinical/observational studies was established by careful reading of the sampled publications and their checking against predefined criteria.

RESULTS

Our study showed that only a minority of experimental preclinical studies had basic principles of design completely implemented (7%), while implementation rate of single aspects of appropriate experimental design varied from as low as 12% to as high as 77%. Only one of the clinical/observational studies had none of the errors searched for (2%), and specific errors rates varied from 10% to 89%. Average impact factor of the surveyed studies was around one, and average publication date recent, less than 5 years ago.

CONCLUSION

Prevalence of preclinical studies that did not follow completely basic principles of research design, and that of clinical/observational studies with errors are high, raising suspicion to validity of their results. If incorrect and not protected against bias, results of published studies may adversely influence future research.

Biofilm Formation of Respiratory Pathogens on Vanillin-Incorporated Denture Base Resin

The adherence of microorganisms to denture base materials and the consequent formation of biofilms on these surfaces are contributing factors to biofilm-related oral and systemic diseases. Aspiration pneumonia is a potentially life-threatening respiratory infection associated with the entry of foreign materials into the bronchi. Vanillin-incorporated polymethyl methacrylate (PMMA) resin has been developed for the use in dentistry and demonstrated to have antimicrobial activity. Objective: To evaluate antimicrobial property of vanillin-incorporated PMMA denture base resin on biofilm formation of respiratory pathogens. Materials and methods: The heat polymerized PMMA denture base resin samples (Siam Cement Group, Thailand) were prepared according to the percentage of vanillin incorporation (0%, 0.1% and 0.5% vanillin). Another group of commercial resin samples without vanillin (Triplex®, Ivoclar Vivadent, USA) was prepared in the same manner. All samples were coated with sterile unstimulated saliva collected from three healthy adult volunteers at 37 °C for 60 min. The respiratory pathogenic bacteria used in this study were Staphylococcus aureus ATCC 5638, Streptococcus pneumoniae ATCC 49619, and Pseudomonas aeruginosa ATCC 27853. They were prepared to a concentration of approximately 107 colony forming unit (CFU)/mL. The bacterial biofilm formation was done in 96-well plate and incubated at 37°C for 24-48 h. The amount of biofilm was quantified by Cell Counting Kit WST-8 (Dojindo Molecular Technologies, USA) at 420 nm. All tests were performed in triplicate on three separate occasions. One-way ANOVA and Turkey’s test were used for the statistical analysis. Results: The vanillin-incorporated resin groups (0.1% and 0.5% vanillin) had a significant reduction of S. aureus and P. aeruginosa biofilm mass compared with resins without vanillin (0% vanillin and commercial resin groups). No significant difference was observed in the S. pneumonia biofilm formation. Up to 80% and 33% reductions of biofilm mass were demonstrated on P. aeruginosa and S. aureus, respectively. Conclusion: The incorporation of vanillin to denture base PMMA resin could significantly inhibit biofilm formation of respiratory pathogens. Using this PMMA resin, denture base materials with antimicrobial property can be applied to reduce a risk of respiratory infection in denture wearing patients.

Long-term effects of penicillin resistance and fitness cost on pneumococcal transmission dynamics in a developed setting

BACKGROUND

The increasing prevalence of penicillin non-susceptible pneumococci (PNSP) throughout the world threatens successful treatment of infections caused by this important bacterial pathogen. The rate at which PNSP clones spread in the community is thought to mainly be determined by two key determinants; the volume of penicillin use and the magnitude of the fitness cost in the absence of treatment. The aim of the study was to determine the impacts of penicillin consumption and fitness cost on pneumococcal transmission dynamics in a developed country setting.

METHODS

An individual-based network model based on real-life demographic data was constructed and applied in a developed country setting (Sweden). A population structure with transmission of carriage taking place within relevant mixing groups, i.e. families, day care groups, school classes, and other close contacts, was considered to properly assess the transmission dynamics for susceptible and PNSP clones. Several scenarios were simulated and model outcomes were statistically analysed.

RESULTS

Model simulations predicted that with an outpatient penicillin use corresponding to the sales in Sweden 2010 (118 recipes per 1,000 inhabitants per year), the magnitude of a fitness cost for resistance must be at least 5% to offset the advantage of penicillin resistance. Moreover, even if there is a fitness cost associated with penicillin resistance, a considerable reduction of penicillin usage appears to be required to significantly decrease the incidence of PNSP in a community.

CONCLUSION

The frequency of PNSP clones is hard to reverse by simply reducing the penicillin consumption even if there is a biological cost associated with resistance. However, because penicillin usage does promote further spread of PNSP clones, it is important to keep down penicillin consumption considering future resistance problems.