[Potential use of liposomes in tuberculosis treatment]

Tuberculosis is among the infectious diseases with the highest mortality and morbidity worldwide, behind the COVID-19 pandemic. It can affect any organ, although the respiratory infection is the most common. The correct activation of the immune response eliminates or contain the bacteria; however, the active disease is progressive and must be treated under strict supervision. Treatment for tuberculosis is prolonged and consists of a combination of several antibiotics associated with a wide variety of adverse effects. These effects are the main cause of therapeutic abandonment, which facilitates the appearance of drug-resistant strains. Hence the importance of developing new therapeutic strategies to reduce the dose of the drug or its administration time. To achieve these objectives, the use of nano-vehicles, which are controlled and directed drug release systems, has been proposed. Specifically, liposomes are formulations that have advantages when administered by the respiratory route since they facilitate the reach of the respiratory mucosa and the lungs, which are the main organs affected by tuberculosis. This review analyzes the use of nano-vehicles as effective drug delivery systems and the formulations under study. Perspectives for the application of nanotechnology in the development of new pharmacological treatments for tuberculosis are also proposed.

[New antibiotics to deal with antibiotic resistance]

NEW ANTIBIOTICS TO DEAL WITH ANTIBIOTIC RESISTANCE. The current increase in antibiotic resistance exposes to the risk of therapeutic impasse. To deal with this public health problem, developing new antibiotics that are effective (directly or in combination with older drugs) against these multi-resistant bacteria seems important. Over the last 10 years, new drugs (beta-lactams, beta-lactamase inhibitors, cyclin and carbapenems) have been developed against Gram-negative bacteria. A new oxazolidinone, two glycopeptides and a quinolone have been developed against Gram-positive bacteria. Their use must absolutely be controlled to avoid resistance mechanisms emergence.

[The Epidemiological Profile of the Isolation of 'Problem' Microorganisms]

INTRODUCTION

Infections are a major problem and the presence of drug-resistant microorganisms has significant clinical and economic impact. The present study aims to evaluate the epidemiological profile of "problem" microorganisms isolated in a hospital in the north of Portugal.

MATERIAL AND METHODS

All isolated microorganisms were analyzed, between January 2014 and June 2015. Data obtained was then processed using statistical software.

RESULTS

We analyzed 8146 microbiological isolations and found a prevalence of 23% of 'problem' microorganisms (in descending order of frequency: Enterococcus, Pseudomonas, Staphylococcus aureus e Streptococcus pneumonia), 57.55% of which isolated in male patients. The most frequent mechanism of drug resistance for the overall sample was the production of extended-spectrum beta-lactamase, and resistance to oxacillin for 'problem' microorganisms.

DISCUSSION

In this sample, we observed a much higher prevalence of 'problem' microorganisms than that reported in other countries, which shows the need of improvement of surveillance mechanisms and treatment of these cases. Microorganisms that showed higher resistance were Staphylococcus aureus (resistant to oxacillin) and Enterococcus (resistant to vancomycin). Those were isolated in patients with a higher mean age compared to non-resistant microorganisms. Most of these microorganisms were isolated in hospitalized patients or intermediate and intensive care units, what relates them with healthcare associated infections.

CONCLUSION

The prevalence of infection by 'problem' microorganisms during the studied period was 23%. The detection and control of the spread of these microorganisms are paramount due to its impact on health costs, morbidity and survival of patients.

Mutations in Streptomycin Resistance Genes and Their Relationship to Streptomycin Resistance and Lineage of Mycobacterium tuberculosis Thai Isolates

BACKGROUND

Streptomycin (SM) is recommended by the World Health Organization (WHO) as a part of standard regimens for retreating multidrug-resistant tuberculosis (MDR-TB) cases. The incidence of MDR-TB in retreatment cases was 19% in Thailand. To date, information on SM resistance (SMR) gene mutations correlated to the SMR of Mycobacterium tuberculosis Thai isolates is limited. In this study, the mutations in rpsL, rrs, gidB, and whiB7 were investigated and their association to SMR and the lineage of M. tuberculosis were explored.

METHODS

The lineages of 287 M. tuberculosis collected from 2007 to 2011 were identified by spoligotyping. Drug susceptibility profiles were evaluated by the absolute concentration method. Mutations in SMR genes of 46 SM-resistant and 55 SM-susceptible isolates were examined by DNA sequencing.

RESULTS

Three rpsL (Lys43Arg, Lys88Arg, and Lys88Thr) and two gidB (Trp45Ter and Gly69Asp) mutations were present exclusively in the SM resistant M. tuberculosis. Lys43Arg rpsL was the most predominant SMR mutations (69.6%) and prevailed among Beijing isolates (p<0.001). No SMR-related mutation in was found rrs. The combination of rpsL and gidB mutations provided 76.1% sensitivity for detecting SMR in M. tuberculosis Thai isolates. whiB7 was not responsible for SMR in SM resistant isolates lacking rpsL and rrs mutations. The significance of the three gidB mutations, 276A>C, 615A>G, and 330G>T, as lineage signatures for Beijing and EAI were underscored. This study identified 423G>A gidB as a novel sub-lineage marker for EAI6-BGD1.

CONCLUSION

Our study suggested that the majority of SMR in M. tuberculosis Thai isolates were responsible by rpsL and gidB polymorphisms constantly providing the novel lineage specific makers.

Fresh Garlic Extract Enhances the Antimicrobial Activities of Antibiotics on Resistant Strains in Vitro

Background:

Infections caused by strains with multi-drug resistance are difficult to treat with standard antibiotics. Garlic is a powerful remedy to protect against infections of many bacteria, fungi and viruses. However, little is known about the potentials of fresh garlic extract (FGE) to improve the sensitivity of multi-drug resistant strains to antibiotics.

Objectives:

In this study, we used the disk diffusion method to investigate the antimicrobial activities of FGE and the combination of antibiotics with FGE, on methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Candida albicans, to evaluate the interactions between antibiotics and FGE.

Materials and Methods:

Clinical isolates were isolated from clinical specimens obtained from the inpatients at the First Affiliated Hospital of Xi’an Jiaotong University Health Science Center. The isolates consisted of MRSA, (n = 30), C. albicans (n = 30) and P. aeruginosa (n = 30). Quality control for CLSI (Clinical and Laboratory Standards Institute) disk diffusion was performed using S. aureus ATCC®25923, C. albicans ATCC®90028 and P. aeruginosa ATCC®27853. The 93 microorganisms were divided into four groups in a factorial design: control (deionized water), FGE, antibiotics without FGE, and antibiotics with FGE. Next, antibacterial activity was evaluated by measuring the diameter of inhibition zones according to performance standards for antimicrobial susceptibility testing of the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS).

Results:

Fresh garlic extract displayed evident inhibition properties against C. albicans and MRSA, yet weak inhibition properties against P. aeruginosa. Additionally, FGE showed the potential to improve the effect of antibiotics on antibiotic resistant pathogens. The synergism of fluconazole and itraconazole with FGE on C. albicans yielded larger sized inhibition zones compared with fluconazole and itraconazole without FGE (P < 0.01). The factorial analysis represents intense positive interaction effects (P < 0.01). The synergism of cefotaxime and ceftriaxone with FGE on P. aeruginosa yielded larger sized inhibition zones than cefotaxime and ceftriaxone without FGE (P < 0.01). The factorial analysis represents intense positive interaction effects (P < 0.01).

Conclusions:

The results suggest that FGE can improve the antibiotic sensitivity of these pathogens to some antibiotics.

Bacteriologic profile of pericardial infections after cardiac surgery: study in an Iranian cardiovascular tertiary care center

BACKGROUND

Bacterial pericarditis is an important cause of post-surgery mortality and morbidity. This can be a preventable complication and the involved pathogens vary according to the time and location.

OBJECTIVES

The aim of this study was to investigate the bacteriologic profile in patients with pericardial infections after cardiac surgery in the largest tertiary care center for cardiovascular diseases in Iran. The results can be applied for prevention, diagnosis, and treatment of similar patients in Iran.

PATIENTS AND METHODS

This prospective study was performed in Rajaie Cardiovascular Medical and Research Center (RCMRC), the largest tertiary care center for cardiovascular disease in Iran from March 2011 to March 2012. Patients who had undergone cardiac surgery with cardiopulmonary bypass and showed suggestive sign and symptoms of pericardial infections were registered and samples from their pericardial fluids were obtained to perform standard bacteriologic and antibiogram tests.

RESULTS

A total of 158 patients were registered. Bacteriologic findings were positive in 30 patients (19%). Staphylococcus epidermidis was the most frequent isolated organism, which was found in 22 patients (73.3%) with eight of them being methicillin-resistant strains.

CONCLUSIONS

The bacteriologic profile in our patient is specific to our own community. Knowledge about this profile can help us to improve prevention, diagnosis, and treatment of the affected patients.

Changing molecular epidemiology of group B streptococcus in Korea

The prevalence of group B streptococcus (GBS) among pregnant women and disease burdens in neonates and adults are increasing in Korea. Colonizing isolates, collected by screening pregnant women (n=196), and clinical isolates collected from clinical patients throughout Korea (n=234), were serotyped and screened for antibiotic resistance. Serotype III (29.8%) and V (27.7%) predominated, followed by Ia (17.0%). Antibiotic resistance was higher among clinical than colonizing isolates for erythromycin (35.1% and 26.9%; P=0.10) and for clindamycin (49.4% and 42.1%; P=0.17). erm(B) occurred in 91.9% of erythromycin resistant isolates, and 84.0% of isolates resistant to clindamycin. Only five isolates (4.2%) resistant to erythromycin were susceptible to clindamycin; by contrast, and unique to Korea, 34% of isolates resistant to clindamycin were erythromycin susceptible. Among these 60 erythromycin-susceptible & clindamycin-resistant isolates, 88% was serotype III, and lnu(B) was found in 89% of strains. Four fifths of the serotype V isolates were resistant to both erythromycin and clindamycin. Further characterization of the genetic assembly of these resistance conferring genes, erm(B) and lnu(B), will be useful to establish the clonal lineages of multiple resistance genes carrying strains.