Comparison of the GeneXpert® MTB/RIF Test and Conventional Methods in the Diagnosis of Mycobacterium tuberculosis

BACKGROUND

The objective of this study is to evaluate the performance of the GeneXpert MTB/RIF system in Mycobacterium tuberculosis (MTB) diagnosis and the detection of rifampicin resistance in pulmonary and extrapulmonary clinical samples.

METHODS

A total of 849 samples (611 pulmonary and 238 extrapulmonary), which were sent to the laboratory of our hospital on suspicion of MTB, were included in the study. The samples cultured on Lowenstein Jensen medium and Mycobacteria Growth Indicator Tubes. All samples were also tested with the GeneXpert MTB/RIF test. The drug susceptibility test was determined using the Bactec MGIT 960 system.

RESULTS

MTB grew in the culture in 84 (9.8%) of all samples, and 78 (9.1%) were found to be positive by the GeneXpert MTB/RIF test, while acid-fast bacillus (AFB), MTB/RIF test, and culture positivity were 41 (6.7%), 74 (12.1%), and 75 (12.3%), respectively, in pulmonary samples, and these values were found to be 2 (0.8%), 4 (1.7%), and 9 (3.8%), respectively, in extrapulmonary samples. In the automated culture and susceptibility system, rifampicin resistance was detected in only one of 84 (2.6%) isolated strains. This resistant strain was also identified by the GeneXpert MTB/RIF test. According to the culture results of all samples examined, the sensitivity of the GeneXpert MTB/RIF test was calculated as 83.3%, specificity as 98.9%, PPV as 89.7%, and NPV as 98.1%.

CONCLUSIONS

The GeneXpert MTB/RIF test used in the study was found to be highly successful, very quick, and requiring low workload in pulmonary samples and extrapulmonary samples in terms of sensitivity and specificity. It was observed that it can be used safely due to its high sensitivity, especially in AFB-positive samples.

The Prevalence of Mixed Genotype Infections in Turkish Patients with Hepatitis C: a Multicentered Assessment

BACKGROUND

HCV virus infections are one of the major health problems in the world that can cause cirrhosis and liver cancer at a higher rate than other hepatitis data. The aim of this study was to determine the prevalence of mixed infections with different HCV genotypes in Turkey and also to evaluate the current HCV genotype and sub-type distributions by a multicentered assessment.

METHODS

The HCV genotype data of 17,578 hepatitis C patients collected from 23 centers from different geographic regions covering all Turkey were collected. The data included information about the HCV genotypes in the last 10 years (between 2007 and 2016), demographic properties of the patients and the methods/systems used to determine the genotypes.

RESULTS

Two hundred twenty-eight of the patients (1.3%) had mixed genotype. The most common mixed genotype combination was 1b + 4 (0.83%) followed by 1a + 1b (0.26%). Genotype distribution varies according to geographical regions. However, genotype 1 (82.92%) was the most common genotype in all regions and all years. This was followed by genotype 3 (7.07%) and genotype 4 (5.43%). A variety of methods were used by the centers including sequencing, pyrosequencing, real-time PCR, in-house RFLP, reverse hybridization (LIPA), and hybridization.

CONCLUSIONS

Infection with mixed HCV genotypes in Turkey is uncommon. Genotype distribution varies according to geographic regions; the most common genotype 1 is encountered all over the country, while genotypes 3 and 4 are only in some of the centers. Since there is limited information about mixed HCV infection, further investigations are needed to determine the clinical importance of mixed HCV infection.

The Effect of Concurrent Tetanus-diphtheria Vaccination on the Antibody Response to Rabies Vaccine: A Preliminary Study

The number of studies in the literature investigating the effect of tetanus vaccination on rabies prophylaxis is rather limited. In this study, we aimed to investigate the effect of concurrent tetanus-diphtheria (Td) vaccination on the antibody response to rabies vaccine. The data of consecutive 80 patients who presented to Sakarya University Training and Research Hospital, Department of Emergency due to rabies suspected exposure between 15 October 2012 and 12 June 2013 were enrolled to this study. Postexposure rabies prophylaxis had been given to all cases, however concurrent tetanus vaccination had been administered to some of them according to their need. Cases were divided into two parts according to their receipt of tetanus prophylaxis as rabies only group (group R, n=37), and rabies and tetanus-diphtheria group (group R+Td, n=43). Rabies antibody levels were tested in sera of the cases at first and postvaccination 21st day. The median antibody levels of each group were measured and compared with each other statistically. In our study, postvaccination 21st day antibody level of group R was 0.68 IU/ml (IQR: 0.79), while the same for group R+Td was 0.52 IU/ml (IQR: 0.48) (p=0.022). Concurrent administration of Td vaccine was found to have a significant negative effect on the antibody response to rabies vaccine. Our results should be confirmed with further studies including more cases.

The Seroprevalence of Hand-Foot-Mouth Disease in Preschool Children

Hand-foot-mouth disease (HFMD) is a systemic and mostly uncomplicated infectious disease caused by the virus of the enterovirus family and manifests as skin and mucosal lesions. Enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the most commonly detected infectious agents. It is generally observed in children under 5 years of age. In this study, our objective was to determine the seroprevalence of HFMD in preschool children in Sakarya region. A total of 380 children between 1 and 6 years of age were included in the study. Sociodemographic information, clinical findings, and possible risk factors were recorded on a data collection form. Later, serum anti-EV71 and anti-CA16 IgG (immunoglobulin G) antibodies were measured by ELISA. Amongst the 380 children, EV71 IgG positivity was 57.9% and CA16 IgG antibody positivity was 57.4%. There was no difference in seroprevalence between the genders (p > 0.05). Anti-EV71 and anti-CA16 IgG antibody positivity was significantly higher in children aged 1, 2, 3, and 4 years than in 5-year olds (p < 0.05). Seroprevalence was significantly lower in children of mothers who washed their hands before feeding (p < 0.01). High HFMD seroprevalence (> 50%) was observed in the preschool period in the Sakarya region, especially in children aged 1 to 4 years. To prevent infections for which there is no specific treatment, it is very important that the hygiene rules are complied with; in particular, children and their caregivers should pay attention to hand cleansing. We believe that more seroprevalence studies should be performed from different regions to show the status of the disease in our country.

Detection and Evaluation of Escherichia coli O157:H7 and Shiga-toxin Genes stx1, stx2 in Cattle Meat Samples

<i>Background:</i> Screening of transmission routes and routine control of the food for foodborne-pathogens are vital in terms of public health. In this study, we aimed to investigate and evaluate the presence of E. coli O157:H7 strains and toxins in the cattle meat samples collected from different markets and butchers. <i>Methods:</i> We collected 116 raw minced cattle beef samples from the supermarkets and the butcher stores. We used bacterial culture-based conventional isolation methods as recommended by the CDC and FDA determination of STEC in the minced cattle beef samples. Then we used PCR to detect stx genes in sorbitol negative E. coli. This way, we indirectly demonstrated the presence of the stx genes in meat samples. Additionally, we used an agglutination test for the detection of E. coli O157:H7. <i>Results:</i> E. coli O157-suspected isolates were found in 17 (14.6%) out of 116 raw minced meat samples examined with tests. STEC stx toxin gene was found in 14 (12.06%) of the sorbitol-negative E. coli isolates tested with real-time PCR method. There was no statistical difference between samples collected from markets and butchers according to STEC stx toxin gene positivity rate. Latex agglutination method performed very poor results in suspected strains compared the PCR results (p < 0.05). <i>Conclusions:</i> Meat products sold in markets and butchers carry low but similar risks for infections and epidemics in our region. In the studies that evaluate the presence of the STEC, agglutination methods cannot be trusted alone and, therefore, this test should be combined with at least one of the conventional microbiological or molecular methods.

Nail scissors and fingernails as reservoirs of hepatitis B virus DNA: Role of nail scissors in household transmission of hepatitis B virus

BACKGROUND

No study in the current literature has scientifically clarified the transmission of hepatitis B virus (HBV) via personal hygiene tools. We determined risk of household transmission of HBV via nail scissors. Moreover, we assessed whether nails from HBV-infected people contained HBV, and evaluated correlations of HBV DNA levels of serum, nail specimens, and nail scissors.

METHODS

Seventy patients testing positive for the surface antigen of the hepatitis B virus (63 positive for HBV DNA) treated for HBV infection and 27 healthy individuals were included. Real-time polymerase chain reaction method was used to detect HBV DNA levels in sera, nail, and nail scissors.

RESULTS

HBV DNA was detected on 27% of nail scissors and in 50% of nail specimens from 63 serum HBV DNA-positive patients. Serum HBV DNA level >10⁵ IU/mL was associated with 71.8% probability of nail scissors being HBV DNA-positive (P < .05). Serum HBV DNA level >10⁷ IU/mL was associated with 71.5% probability of fingernails being HBV DNA-positive (P > .05). Shared-use of nail scissors was correlated with surface antigen of the hepatitis B virus positivity and total hepatitis B core antibody/immunoglobulin G positivity. A high HBV DNA level was detected in nail scissors and low level HBV DNA in the nails of persons with high serum HBV DNA levels.

CONCLUSIONS

Nail scissors, shared-use of nail scissors, and duration of shared use play important roles in household transmission of HBV. Level of education within society in this regard should be increased via mass media.

Comparison of Novel Blood Culture System DL-Bt112TM with BacT/Alert 3DTM by Using Clinical Samples

BACKGROUND

Blood cultures are the main diagnostic laboratory tool to detect bloodstream infections. Many clinical microbiology laboratories utilize automated blood culture systems to isolate infectious agents from blood samples. The diagnostic performance and time-to-detection values of the novel automated blood culture system, DLBt112TM (DL), was compared with BacT/Alert 3DTM (B3D) in this prospective comparative study with clinical samples.

METHODS

A total of 356 blood culture sets (178 sets for each system) were evaluated over a 6-month period in a university hospital. Two sets of blood culture samples (one for DL and one for B3D) were drawn from intensive care unit patients who were suspected to have bloodstream infections. BacT/ALERT FA FAN® Aerobic/Anaerobic blood culture bottles for B3D and FAN adult anaerobic/aerobic blood culture bottles for DL were used. The Vitek® 2 automated system was used for identification of the isolated bacteria.

RESULTS

We evaluated 178 sets from 105 patients consisting of 712 blood culture bottles in total. In total, 294 negative bottles and 47 positive bottles were detected by both systems. Recovery rate of the B3D (96.7%) was significantly higher than that of DL (79.0) (p < 0.05). We determined significant differences between DL and B3D in terms of time-to-detection values for gram negatives (p = 0.006) and contaminants (p = 0.048). Overall, B3D had shorter time-to-detection mean values.

CONCLUSIONS

The recovery rate of DL was unfavorably low and time-to-detection values for DL were significantly higher than that of B3D. This might result from the ingredients of the culture bottles since the detection technologies of the systems were similar.

Socioeconomic indicators are strong predictors of hepatitis A seroprevalence rates in the Middle East and North Africa

The goal of this analysis was to examine the association between age-specific hepatitis A virus (HAV) seroprevalence rates and various socioeconomic indicators within the Middle East and North Africa (MENA) region. We conducted a systematic review of all recently published studies on HAV conducted in the MENA region and identified the highest quality studies for inclusion in our analysis. We calculated the age at midpoint of population immunity (AMPI) for each study and estimated seroprevalence rates at the ages of 5, 10, and 15 years. Next, we identified the correlations between these metrics and several socioeconomic variables. HAV data collected in or after 2000 were available for 14 of the 19 countries in the MENA region. Four of the 14 included countries had intermediate HAV endemicity (Algeria, Saudi Arabia, Turkey, and UAE), five had high endemicity (Iran, Jordan, Lebanon, Morocco, and Tunisia), and five had very high endemicity (Egypt, Iraq, Palestine, Syria, and Yemen). Water and sanitation were not significant predictors of AMPI or seroprevalence, most likely because most countries in this region have high rates of access to these utilities. However, gross domestic product (GDP), gross national income (GNI), and the human development index (HDI) were all highly associated with AMPI and prevalence. The observed correlations suggest that of the MENA countries without recent HAV data, Bahrain, Kuwait, and Qatar most likely have low endemicity, Oman likely has intermediate endemicity, and Libya likely has high endemicity. While it is unlikely that a single correlation model would be suitable for use in all world regions, the approach utilized in this analysis might provide a simple but accurate method for using economic data to impute the endemicity profiles of countries without recent data in regions where at least several neighboring countries have conducted recent serostudies.

Usefulness of soluble urokinase plasminogen activator receptor (suPAR) as an inflammatory biomarker in obese children

OBJECTIVE

Soluble urokinase plasminogen activator receptor (suPAR) has emerged as a relatively new biomarker that reflects increased inflammatory status and been associated with cardiovascular risk. We wanted to investigate the predictive value and usefulness of suPAR as an inflammatory biomarker in obese children.

METHODS AND RESULTS

Of the total 136 participants, 76 (36 male, 40 female) were in obese group and 60 (24 male, 36 female) were in control group. The median age was 12.05 (6.16-17.30) years old for obese group, and 12.83 (8.00-16.75) years old for control group. Obese children had statistically significantly higher heart rate, systolic and diastolic blood pressure, EAT and LV mass than control group (p<0.01). The median suPAR level in obese group was not statistically different than in control group (0.54 vs. 0.59, p=0.26). The median hsCRP level in obese group was found statistically significantly higher than in control group (1.97 vs. 0.41, p<0.01). A significant positive correlation between hsCRP and BMI in the obese participants was found (r=0.45, p<0.01), but not a relationship between suPAR and BMI (r=-0.21, p>0.05).

CONCLUSION

Our research did not demonstrate the usefulness of suPAR as an inflammatory biomarker and a predictive value for future atherosclerosis in obese children. Further studies with larger sample size are required to determine whether suPAR is useful as an inflammatory biomarker in childhood obesity.

Intra-Abdominal Abscess and Primary Peritonitis Caused by Streptococcus anginosus

Introduction

The Streptococcus anginosus group of bacteria are low-virulence bacteria existing as commensals in the oral flora and gastrointestinal tracts of humans. S. anginosus may spread to the blood in individuals with poor oral hygiene in cases of oral infections, such as gingivitis and tooth abscesses, that develop following the loss of mucosal unity. This may lead to infections in the whole body, primarily as brain and liver abscesses.

Case Presentation

A 32-year-old male patient presented with complaints of nausea, vomiting, and diffuse abdominal pain. Diffuse abdominal tenderness and rebound tenderness were detected particularly in the epigastrium and right upper quadrant. Laboratory assessment revealed a leukocyte count of 20,500/mm³. Free fluid around the liver and heterogeneous areas of abscess formation in the right lateral gallbladder were revealed on abdominal computed tomography. Diffuse adhesions between the bowel and seropurulent free liquid in the abdomen were detected on surgical exploration, and a sample was taken for cultures. The patient was discharged without complications on the sixth postoperative day and his antibiotic course was completed with 4 weeks of oral treatment. We reviewed the literature for similar cases of disseminated pyogenic infections caused by the S. anginosus group.

Conclusions

It should be kept in mind that the oral flora bacterium S. anginosus may cause transient bacteremia and deep-seated organ abscesses in immunodeficient patients with poor oral hygiene. Such patients with intra-abdominal abscesses should be treated with antibiotics and surgery.

A rare cause of infection, Raoultella planticola: emerging threat and new reservoir for carbapenem resistance

BACKGROUND

Severe cases of infections caused by Raoultella planticola are constantly being reported from all over the world with the increase in drug-resistance patterns. In this study, we retrospectively evaluated the clinical characteristics of R. planticola infections with patients' demographics and antimicrobial susceptibilities of the R. planticola isolates.

METHODS

R. planticola isolates were retrospectively evaluated. VITEK 2^® automated system was used for identification and antimicrobial susceptibility testing. Verification of the low-discriminated isolates was analyzed with MALDI-TOF method using VITEK MS^® system. Gene-Xpert^® system was used for detection of bla _IMP-1-, bla _KPC-, bla _NDM-1-, bla _OXA-48- and bla _VIM-type carbapenemases. The data of the patients with R. planticola infection were collected from hospital records.

RESULT

During the 4-year period, 42 episodes of R. planticola infections were detected. MALDI-TOF was used for 11 of the low-discriminated isolates, and 1 of which identified as R. terrigena was excluded. Carbapenems and aminoglycosides were the most effective antimicrobial agents. Extended spectrum beta-lactamases were detected in seven of the isolates. Three carbapenem-resistant isolates were detected as bla _OXA-48-type carbapenemase carrier. Nosocomial R. planticola infections constituted 80.9 % (n = 34) of the infections. Most common infections related with R. planticola were blood stream infections (n = 24) (p < 0.005). The presence of indwelling catheter and intensive care unit stay were the most common detected risk factors (p < 0.005). Diabetes mellitus and chronic renal insufficiency commonly accompanied the infections (p > 0.005).

CONCLUSIONS

Challenging infections caused by Raoultella spp., like those of multidrug resistant Klebsiella spp., will probably become a concern for clinicians as well as microbiologists . In literature, there were few cases, but we believe that the incidence of Raoultella spp. infections, which may result from misidentification, are more common than expected , and it is not unlikely that there will be a gradual increase and spread in multidrug-resistant isolates.

The carbapenem-resistant Enterobacteriaceae threat is growing: NDM-1 epidemic at a training hospital in Turkey

BACKGROUND

Recently, new carbapenemases in Enterobacteriaceae strains and non-fermentative gram-negative bacilli have been reported. The New Delhi metallo-β-lactamase-1 (NDM-1) is a major problem around the world. The purpose of this article is to address the NDM-1 Klebsiella pneumoniae epidemic detected in eight cases in our hospital.

METHODS

Bacteria identified in this epidemic were from patients already admitted to the intensive care unit of the Sakarya University Training and Research Hospital during efforts toward establishment of infection surveillance and control program. Antimicrobial susceptibility testing of strains was performed using the VITEK 2 system (bioMérieux, France), E-test gradient strips (bioMérieux, France), and the disc diffusion test. For the metallo-beta-lactamase activity, the combined disc diffusion test and modified Hodge test as phenotypic tests were performed. To identify the resistance gene, the Xpert Carba-R kit (Cepheid Inc., USA) and an in-house multiplex polymerase chain reaction (PCR) method designed for five common carbapenemase genes (IMP, VIM, KPC, NDM-1, and OXA-48) were employed. The clonal relationship of these strains was explored by the repetitive PCR (rep-PCR, DiversiLab System, bioMérieux, France) method.

RESULTS

During the December 2014 to March 2015 period, NDM-1 positive K. pneumoniae strains were detected in eight patients. All of these strains were found to produce NDM-1, while two of them also revealed the presence of OXA-48. The rep-PCR results reveal a clonal proximity of 95 % for six of the eight strains.

CONCLUSIONS

Our findings suggest the tendency of NDM-1-producing strains to spread in our country as well. A carbapenem-resistant K. pneumoniae threat may pose a great risk to our country. It is clear that more comprehensive infection control precautions should be implemented in our hospitals.

A severe Morganella morganii endophthalmitis; followed by bacteremia

Morganella morganii is rarely isolated from nosocomial infections. However, postoperative infections due to Morganella spp. were documented in literature and eye involvements of the infections usually result in severe sequels. We present a severe case infection, which was caused by M. morganii subsp. morganii, firstly appearing as conjunctivitis and complicated by bacteremia. The infectious agent isolated from both conjunctival and consecutive blood cultures. Identification and antimicrobial susceptibility tests were performed with the Vitek 2(®) automated system. The isolate was resistant to cephalosporins and carbapenems and it had ability to produce extended spectrum beta-lactamases. Patient was successfully treated with intravenous ciprofloxacin according to susceptibility test results. This is the first report of M. morganii infection detected as a local infection then complicated by bacteremia.

A Multicenter Evaluation of Blood Culture Practices, Contamination Rates, and the Distribution of Causative Bacteria

BACKGROUND

The prognostic value of blood culture testing in the diagnosis of bacteremia is limited by contamination.

OBJECTIVES

In this multicenter study, the aim was to evaluate the contamination rates of blood cultures as well as the parameters that affect the culture results.

MATERIALS AND METHODS

Sample collection practices and culture data obtained from 16 university/research hospitals were retrospectively evaluated. A total of 214,340 blood samples from 43,254 patients admitted to the centers in 2013 were included in this study. The blood culture results were evaluated based on the three phases of laboratory testing: the pre-analytic, the analytic, and the post-analytic phase.

RESULTS

Blood samples were obtained from the patients through either the peripheral venous route (64%) or an intravascular catheter (36%). Povidone-iodine (60%) or alcohol (40%) was applied to disinfect the skin. Of the 16 centers, 62.5% have no dedicated phlebotomy team, 68.7% employed a blood culture system, 86.7% conducted additional studies with pediatric bottles, and 43.7% with anaerobic bottles. One center maintained a blood culture quality control study. The average growth rate in the bottles of blood cultures during the defined period (1259 - 26,400/year) was 32.3%. Of the growing microorganisms, 67% were causative agents, while 33% were contaminants. The contamination rates of the centers ranged from 1% to 17%. The average growth time for the causative bacteria was 21.4 hours, while it was 36.3 hours for the contaminant bacteria. The most commonly isolated pathogens were Escherichia coli (22.45%) and coagulase-negative staphylococci (CoNS) (20.11%). Further, the most frequently identified contaminant bacteria were CoNS (44.04%).

CONCLUSIONS

The high contamination rates were remarkable in this study. We suggest that the hospitals' staff should be better trained in blood sample collection and processing. Sterile glove usage, alcohol usage for disinfection, the presence of a phlebotomy team, and quality control studies may all contribute to decreasing the contamination rates. Health policy makers should therefore provide the necessary financial support to obtain the required materials and equipment.

Comparison of keypads and touch-screen mobile phones/devices as potential risk for microbial contamination

INTRODUCTION

Touch-screen mobile phones/devices (TMPs/Ds) are increasingly used in hospitals. They may act as a mobile reservoir for microbial pathogens. The rates of microbial contamination of TMPs/Ds and keypad mobile phones (KMPs) with respect to different variables including use by healthcare workers (HCWs)/non-HCWs and the demographic characteristics of users were investigated.

METHODOLOGY

A total of 205 mobile phones/devices were screened for microbial contamination: 76 devices belonged to HCWs and 129 devices belonged to the non-HCW group. By rubbing swabs to front screen, back, keypad, and metallic surfaces of devices, 444 samples were collected.

RESULTS

Of 205 mobile phones/devices, 143 (97.9%) of the TMPs/Ds and 58 (98.3%) of the KMPs were positive for microbial contamination, and there were no significant differences in contamination rates between these groups, although TMPs/Ds had significantly higher microbial load than KMPs (p <0.05). The significant difference in this analysis was attributable to the screen size of mobile phones ≥ 5". Microbial contamination rates increased significantly as phone size increased (p <0.05). Higher numbers of coagulase-negative Staphylococci (CNS) were isolated from KMPs than TMPs/Ds (p = 0.049). The incidence of Enterococcus spp. was higher on the KMPs of HCWs, and methicillin resistant CNS was higher from the TMPs/Ds of non-HCWs (p <0.05). Isolation of CNS, Streptococcus spp. and Escherichia coli was higher from the TMPs/Ds of HCWs (p <0.05).

CONCLUSIONS

We found no significant difference between TMP/Ds and KMPs in terms of microbial contamination, but TMP/Ds harboured more colonies and total microbial counts increased with screen size.

Investigation of Antibacterial Activity and Biofilm Formation of Silicones Coated With Minocycline-Rifampicin, Silver Nitrate, and Nitrofurantoin for Short-term Utilization in In Vitro Urinary System Models

OBJECTIVE

To analyze antimicrobial activity and biofilm formation on silicones coated with antimicrobial substances in in vivo short-term catheterization simulation using our newly developed in vitro urinary system model and to compare minocycline-rifampin (MR)-, silver nitrate-, and nitrofurantoin (NF)-coated silicone discs.

MATERIALS AND METHODS

Silicone discs were exposed to bacterial urine suspension for 168 hours. The antimicrobial activities were assessed in the medium, and the inhibition zone diameters were measured. The weight of the silicones was measured for biofilm growth assessment before and after the experiment, and confocal microscopy images were taken.

RESULTS

Although the inhibition zone diameters of silver nitrate silicones were larger than those of pure silicone (PS), MR, and NF silicones, biofilm formation could not be prevented (P < .05). MR and NF silicones were superior to PS in terms of antimicrobial efficacy and prevention of biofilm formation (P < .05). In terms of biofilm prevention, no differences were detected between NF and MR silicones apart from a slightly superior ability of MR silicones to inhibit Escherichia coli (P > .05). Biofilm formation occurred on all silicone discs.

CONCLUSION

In short-term urinary catheter utilization, antimicrobial efficacy and biofilm formation prevention were superior in coated silicones, regardless of the type of antibiotic used, compared with the control group (PS). As the study was conducted in an in vitro setting, the findings should be substantiated with in vivo studies on the grounds that different results may be obtained in these settings.