Epidemiology of first- and second-line drugs-resistant pulmonary tuberculosis in Iran: Systematic review and meta-analysis

Drug resistance among Mycobacterium tuberculosis (MTB) strains is a growing concern in developing countries. We conducted a comprehensive search for relevant studies in Iran on PubMed, Scopus, and Embase until June 12, 2020. Our study focused on determining the prevalence of antibiotic resistance in MTB isolates, with subgroup analyses based on year, location, and drug susceptibility testing (DST) methods. Statistical analyses were performed using STATA software. Our meta-analysis included a total of 47 articles. Among new TB cases, we found the following prevalence rates: Any-resistance to first-line drugs: 31 % (95 % CI, 24-38), mono-drug resistance: 15 % (95 % CI, 10-22), and multidrug resistance to first-line drugs: 6 % (95 % CI, 4-8). There was a significant variation in the rate of MDR among new TB cases based on the year of publication, location, and DST methods (P < 0.0001). We observed substantial variability in multidrug-resistant TB rates among new cases across the studies. Stratified analyses revealed that publication years and DST methods significantly affected resistance rates. Studies from southern and central Iran reported higher any-drug resistance rates, suggesting regional differences. Among retreatment cases, the prevalence rates were as follows: Any resistance: 68 % (95 % CI 58-78), mono-resistance: 19 % (95 % CI 7-34), multidrug resistance: 28 % (95 % CI 15-43). Our study revealed that the prevalence of drug-resistant TB (DR-TB) among TB cases in Iran is higher than the global average. Particularly, MDR-TB among retreatment TB cases is a significant public health issue.

The prevalence of colistin resistance in clinical Stenotrophomonas maltophilia isolates worldwide: a systematic review and meta-analysis

While trimethoprim-sulfamethoxazole (TMP-SMX) is the first-line therapy of Stenotrophomonas maltophilia infections, colistin is one of the therapeutic options in cases of allergy or resistance to TMP-SMX. However, understanding the global status of resistance to colistin amongst S. maltophilia isolates could be helpful for appropriate antibiotic prescription. This study aimed to conduct a systematic review and meta-analysis to examine the prevalence of colistin resistance in clinical S. maltophilia isolates worldwide. According to eligibility criteria, a total of 61 studies were included in the analysis. The pooled prevalence for colistin resistance was 42% (95% CI: 35-49%), ranging from 0.1 to 97%. Subgroups analysis indicated that, the pooled prevalence of colistin resistance was 44% (95% CI: 29-60%) in 15 studies during 2000-2010, and it was estimated to be 41% (95% CI: 33-50%) in 46 articles from 2011 to 2021. It was 46% (95% CI: 35-58%) in the studies that used broth microdilution method, and 39% (95% CI: 30-49%) in the studies with other used methods. The resistance rate in Asian countries was 45% (95% CI: 31-60%), in European countries was 45% (95% CI: 34-56%) and in the countries of North and South America was 33% (95% CI: 20-46%). Our review showed notable resistance to colistin in clinical S. maltophilia isolates. Given the estimated resistance rates, alternative antibiotics could be preferred to treat serious infections due to S. maltophilia.

High-level Gentamicin Resistance among Clinical Isolates of Enterococci in Iran: a Systematic Review and Meta-analysis

Enterococci have been considered as one of the most common causes of nosocomial infections. The spread of antibiotic resistance has posed a serious challenge to treating the enterococcal infections. High-level aminoglycosides resistance leads to failure in the synergistic combination therapy. This study aimed to estimate the prevalence of high-level gentamicin resistance (HLGR) among clinical isolates of enterococci in Iran.Systematic literature search was conducted in the Web of Science, PubMed, Scopus and Google Scholar electronic databases from ar-ticles which were published from April 2000 to September 2018. Literature search yielded 918 studies. Eligible studies were selected ac-cording to the defined inclusion and exclusion criteria. Statistical heterogeneity was estimated by Q statistic and the I2 index. The Begg's rank correlation test and Egger's weighted regression tests were used to evaluate possible publication bias.Nineteen studies were included in this review. According to the meta-analysis results, the prevalence of HLGR among Enterococcus spp. was 49.4% (95% CI: 42.2%-56.6%). It was estimated 44.3% (95% CI: 38.1%-50.8%) and 66.3% (95% CI: 51.4%-78.6%) for E. faecalis and E. faecium, respectively.Since notable rate of HLGR in enterococci was seen in this analysis, improving the implementation of all aspects of the infection control programmes is required. Accurate and regular monitoring of infection control procedures are necessary for reducing the dissemination of such infections.

High prevalence of vancomycin and high-level gentamicin resistance in Enterococcus faecalis isolates

Multiple drug-resistant enterococci are major cause of healthcare-associated infections due to their antibiotic resistance traits. Among them, Enterococcus faecalis is an important opportunistic pathogen causing various hospital-acquired infections. A total of 53 E. faecalis isolates were obtained from various infections. They were identified by phenotypic and genotypic methods. Determination of antimicrobial resistance patterns was done according to CLSI guidelines. The isolates that were non-susceptible to at least one agent in ≥3 antimicrobial categories were defined as multidrug-resistant (MDR). Detection of antimicrobial resistance genes was performed using standard procedures. According to MDR definition, all of the isolates were MDR (100%). High-level gentamicin resistance was observed among 50.9% of them (MIC ≥ 500 μg/ml). The distributions of aac(6')-Ie-aph(2'')-Ia and aph(3')-IIIa genes were 47.2% and 69.8%, respectively. The aph(2'')-Ib, aph(2'')-Ic, aph(2'')-Id, and ant(4')-Ia genes were not detected. Vancomycin resistance was found in 45.3% of strains. The vanA gene was detected in 37.7% of isolates, whereas vanB and vanC₁ genes were not observed in any strain. Erythromycin resistance rate was 79.2% and the frequencies of ermB and ermC genes were 88.6% and 69.8%, respectively. The ermA and msrA genes were not present in any of the isolates. Our data indicate a high rate of MDR E. faecalis strains. All of high-level gentamicin-resistant isolates carried at least one of aac(6')-Ie-aph(2'')-Ia or aph(3')-IIIa genes. Distribution of vanA was notable among the isolates. In addition, ermB and ermC were accountable for resistance to erythromycin.

In Vitro Anti-mycobacterial Activity of Three Medicinal Plants of Lamiaceae Family

BACKGROUND

Mycobacterium tuberculosis as an intracellular pathogen causes Tuberculosis (TB). Due to the long time required for treatment, hepatotoxicity of drugs and also emergence of Multidrug-Resistant (MDR) and Extremely Drug Resistant (XDR) strains, TB is currently a major public health problem. Some medicinal plants possess remarkable activity against Mycobacterium. Among them, Lamiaceae family are of pharmaceutical interest because of their potential antimicrobial properties. The aim of the study was to evaluate the in vitro activities of Satureja rechingeri, Satureja khuzestanica and Zataria multiflora against MDR M. tuberculosis and two Non-Tuberculous Mycobacteria (NTM).

METHODS

The essential oils were prepared by the standard method. The confirmed strains were obtained from the microbial collection of Tehran University of Medical Sciences. Minimum Inhibitory Concentrations (MICs) of essential oils of plants against mycobacterial strains were determined using standard broth microdilution method.

RESULTS

MDR M. tuberculosis was completely inhibited by Z. multiflora at 78µg/ml concentration. S. rechingeri and S. khuzestanica also showed same anti-mycobacterial activity against MDR M. tuberculosis with MICs of 156 µg/ml. The MICs of the essential oils against M. tuberculosis H37Rv, M. kansasii and M. fortuitum were in the range from 39 to 156 µg/ml.

CONCLUSION

The studied medicinal plants showed notable effects against mycobacterial strains. Our results indicated that utilization of Lamiaceae family can be helpful for treatment of mycobacterial infections.

In vivo Antibacterial and Wound Healing Activities of Roman Chamomile (Chamaemelum nobile)

BACKGROUND

Today considerable number of drugs are produced from plants. Several plants with antibacterial and healing applications are used in medicine such as Roman chamomile (Chamaemelum nobile L.). Wound infection is one of the most prevalent infections among infectious diseases around the world. Due to appearance of drug resistance, researchers are now paying attention to medicinal plants. Therefore, this study was designed to investigate the antimicrobial and wound healing properties of C. nobile against Pseudomonas aeruginosa using in vivo conditions.

METHODS

Ethanolic extract of C. nobile was provided using standard method. The 5% C. nobile ointment was prepared by dissolving lyophilized extract in eucerin. Forty five male rats were obtained from Ilam university. After anesthetization and wound creation, wounds were infected by P. aeruginosa. The rats were divided into three groups, group I was treated with C. nobile ointment, group II was treated with tetracycline ointment and the third group was treated with base gel as control group.

RESULTS

Antibacterial and wound healing activities of C. nobile ointment were more than tetracycline ointment significantly. Our results indicated that extract of C. nobile had effective antibacterial activity and accelerated the progression of wound healing.

CONCLUSION

Our study indicated that antibacterial and wound healing activities of C. nobile ointment were notable. C. nobile therapy in combination with antibiotics can also be useful because medicinal plants contents operate in synergy with antibiotics. These results revealed the value of plant extracts to control antibiotic resistant bacteria in wound infections.

WITHDRAWN: Molecular characterization of glycopeptide and macrolide resistance genes among multidrug-resistant Enterococcus faecalis strains

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Linezolid activity against clinical Gram-positive cocci with advanced antimicrobial drug resistance in Iran

OBJECTIVES

The aim of the study was to investigate the linezolid activity against clinical Gram-positive cocci with advanced antimicrobial drug resistance.

METHODS

A collection of methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant enterococci (VRE), penicillin non-susceptible Streptococcus pneumoniae (PNSP), and group B streptococci (GBS) were isolated from various clinical samples. Antimicrobial susceptibility tests were done using standard methods Subsequently, we investigated linezolid antibacterial activities, the first approved oxazolidinone against isolates by the standard broth microdilution method.

RESULTS

According to our results, MRSA and PNSP isolates were multidrug resistant, and almost half of the VRE isolates were high level gentamicin resistant (HLGR). Furthermore, resistance to linezolid was not seen among the isolates. The MIC₉₀ values for MRSA, VRE, PNSP and GBS isolates were 4μg/ml, 2μg/ml, 1μg/ml, and 0.5μg/ml, respectively. Only 6.25% of vancomycin resistant enterococci showed intermediate susceptibility to this antibiotic.

CONCLUSIONS

These findings indicate that linezolid has an excellent activity against clinical drug resistant Gram-positive isolates in Iran. Constant monitoring and surveillance of linezolid MIC distribution allows the researchers to assess and detect gradual upward MIC drifts.