Journal of Medical Microbiology and Infectious Diseases
Volume:11 Issue: 4, Autumn 2023

Tuberculosis, caused by Mycobacterium tuberculosis, is one of the most common infectious diseases worldwide. Epidemiological studies of M. tuberculosis drug resistance are critical for improving patient treatment approaches and controlling the spread of tuberculosis. The present study aimed to determine antibiotic resistance among M. tuberculosis clinical isolates using the Microplate Alamar Blue Assay (MABA).

In this descriptive cross-sectional study, 25 M. tuberculosis isolates from clinical samples were identified and confirmed using standard microbiological and biochemical tests. Then, the MIC for the antibiotics Bedaquiline, isoniazid, rifampin, ethambutol, ofloxacin, moxifloxacin, capreomycin, and streptomycin was determined using the MABA method. The results were analyzed using SPSS version 16 software.

Among the 25 investigated isolates, the frequencies for MDR, Pre-XDR, and XDR isolates were 20%, 8%, and 32%, respectively. The highest rate of drug resistance was to isoniazid (80%), rifampicin, and ethambutol (76%), and the highest rate of sensitivity was to moxifloxacin (68%). The frequency of isoniazid mono-resistance and rifampicin mono-resistance was 5 cases (50%) and 4 cases (40%), respectively.

Our study revealed an alarming rate of MDR and XDR M. tuberculosis strains, indicating that current first-line treatments may be ineffective for a significant number of patients. The bedaquiline resistance among the isolates with no history of previous exposure to this drug suggests unexplored resistance mechanisms. Molecular techniques to accurately identify these mechanisms may contribute to developing more effective treatment strategies to combat drug-resistant tuberculosis.

Tuberculosis (TB) caused by the bacterium Mycobacterium tuberculosis remains a critical global public health concern due to the high morbidity and mortality rates. Mutation in atpE and Rv0678 genes contributes to drug resistance in M. tuberculosis. This study investigates the antibiotic resistance patterns and mutations in atpE and Rv0678 genes in 22 M. tuberculosis clinical isolates.

Drug susceptibility testing (DST) for rifampin, isoniazid, streptomycin, capreomycin, ofloxacin, kanamycin, and ethambutol was conducted using the proportional method. This was followed by determining the minimum inhibitory concentration (MIC) for bedaquiline (BDQ) via the microplate Alamar blue assay (MABA). Genomic regions encompassing atpE and Rv0678 genes were amplified and sequenced for mutation analysis. Data analysis was performed using SPSS software to interpret mutation patterns concerning drug susceptibility profiles.

Of 22 isolates, 5 (27.8%) were extensively drug-resistant tuberculosis (XDR-TB), and 13 (72.2%) were multi-drug resistant tuberculosis (MDR-TB). Resistance rates to kanamycin, ofloxacin, capreomycin, and streptomycin were 40.6%, 46.3%, 85%, and 74.6%, respectively. Additionally, phenotypic resistance to bedaquiline was observed in 12 (54.5%) isolates. Sequencing revealed no resistance-conferring mutations in the atpE or Rv0678 genes among the isolates.

Our findings showed substantial resistance to first- and second-line drugs in M. tuberculosis clinical isolates. This highlights the necessity for ongoing, comprehensive studies to elucidate the evolving drug resistance patterns and understand the underlying mechanisms in clinical isolates.

The emergence of carbapenem-resistant Enterobacteriaceae (CRE) poses a significant public health concern due to its potential for increased mortality and morbidity. The limited availability of effective antibiotics further exacerbates the dissemination of carbapenem-resistant bacteria. This study aimed to evaluate the prevalence of carbapenem resistance and carbapenemase production in Enterobacteriaceae isolates using the Modified Hodge Test.

This observational study was conducted at the Department of Microbiology, MGM Medical College & Hospital, Aurangabad, Maharashtra, from November 2015 to November 2017. 171 Enterobacteriaceae isolates from various clinical samples were comprehensively tested for carbapenem resistance and carbapenemase production. This involved the use of carbapenem discs (ertapenem, meropenem, and imipenem), E-test strips for ertapenem and meropenem, and the Modified Hodge Test (MHT) for carbapenemase identification.

Among the 171 tested Enterobacteriaceae isolates, a substantial proportion (40%) displayed resistance to carbapenems, as determined by disc diffusion and E-test methods. Among the carbapenem-resistant isolates, 13 were positive for the MHT.

Our study revealed a notable prevalence of carbapenem resistance in Enterobacteriaceae isolates from a tertiary care hospital. The MHT, following Clinical and Laboratory Standards Institute (CLSI) guidelines, demonstrated high sensitivity (> 90%) and specificity (> 90%) for detecting KPC-type carbapenemases in these isolates. Treatment options for CRE infections are limited, with tigecycline and colistin identified as potential options. Our study highlights the importance of promptly diagnosing different carbapenemases using PCR techniques. Consequently, we strongly advocate for implementing robust antimicrobial stewardship programs and infection control practices in healthcare settings to prevent CRE spread effectively.

Increased multidrug-resistant (MDR) Acinetobacter baumannii infections pose a significant challenge in hospital settings. Enhanced resistance to antibiotics like fluoroquinolones and β-lactams necessitates adopting alternative treatment strategies such as metal oxide nanoparticles. This study investigated the synergistic effect of zinc oxide nanoparticles (ZnO-NPs) on ciprofloxacin and ceftazidime activity against MDR A. baumannii.

We examined 30 MDR A. baumannii isolates from intensive care unit (ICU) patients in Iran. ZnO-NPs were synthesized via the solvothermal method and characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) to ascertain their crystalline structure and morphology. Antibacterial activity was evaluated by determining minimum inhibitory concentrations (MICs) and inhibition zones through broth microdilution and disk diffusion methods, using concentrations of ciprofloxacin and ceftazidime in combination with ZnO-NPs.

ZnO-NPs combined with ciprofloxacin 8 μg/mL and ceftazidime 32 μg/mL exhibited inhibition growth percentage (GI%) increases of 44.9% and 31.65%. 

The enhanced in vitro antibacterial effects of combined ZnO-NPs and antibiotics against MDR A. baumannii indicate a synergy. Considering the limited number of isolates, comprehensive research incorporating in vivo models and clinical trials is warranted to evaluate the practicality of this approach in overcoming antibiotic resistance.

The rising foodborne disease outbreaks poses significant challenges to key objectives in food microbiology. This trend is primarily attributed to global population growth and intensified food production. A thorough microbiological assessment of end products is therefore crucial.

We evaluated the bacterial presence and abundance in various dairy products (sour cream, cottage cheese, buttercream, cream cheese, pasteurized milk, protein-rich milk, and yogurt) sourced from a local supermarket in Bosnia and Herzegovina. Two enumeration methods (pour plating and most probable number) were employed alongside morphological, biochemical, and molecular analyses (Gram staining, oxidase test, catalase test, indole test, lipolytic activity assay, and RT-qPCR). Our focus was on spoilage-causing lactic acid bacteria (LAB), hygiene indicator thermotolerant coliforms (TC), and the foodborne pathogen Salmonella spp. 

Six out of seven dairy products harbored high levels of LAB, suggesting potential spoilage, except for cottage cheese. Additionally, both TC and Escherichia coli exceeded acceptable microbial limits, particularly in pasteurized milk. Furthermore, initial tests detected presumptive Salmonella spp. in cream cheese, protein-rich milk, and yogurt.

These results highlight the need for stringent sanitary practices during dairy production to extend product shelf-life and prevent premature spoilage from unwanted bacterial presence. Moreover, eliminating pathogen contamination during manufacturing is crucial to mitigate serious food safety risks, including potential food poisoning.

Tuberculosis (TB) continues to be a significant infectious disease worldwide. The prevalence of TB in Pakistan remains high. A thorough assessment of the population's knowledge about the disease could aid in reducing its transmission. Our objective was to identify demographic and socioeconomic variables that may impact the understanding of TB among Pakistani men (n=3691) and to analyze its influence.

We utilized secondary data from the Pakistan Demographic and Health Survey (DHS), collected between November 2017 and April 2018. We examined participants' knowledge about tuberculosis (TB) through various questions about its characteristics, transmission, curability, and duration. Other factors such as residence, education, internet access, and media preferences were also assessed. A knowledge index ranging from 0 to 9 was developed for each participant in which correct responses were scored as "1," while incorrect ones were scored as "0”. The data were analyzed using both one-way ANOVA and Mann-Whitney U tests.

Most participants were aged 15 to 34 (48.2%) and had completed secondary school (35.8%). 94.3% of participants reported being aware of TB, with higher education showing the highest level of awareness (98.7%). Greater knowledge of TB was associated with reading newspapers or magazines once a week or less (mean score 7.22 ± 1.14, CI: 7.15-7.29, and 7.31 ± 1.11, CI: 7.23-7.40, respectively), watching television once a week or less (mean score 7.22 ± 1.13, CI: 7.00-7.25, and 7.15 ± 1.06, CI: 7.05-7.23, respectively), owning a mobile phone (mean score 7.15 ± 1.1, CI: 7.08-7.19), and having a bank account (mean score 7.33 ± 1.14, CI: 7.28-7.39) (all P<0.01).

There was a significant association between a higher level of TB knowledge and higher educational status, access to print media or television, mobile phone ownership, and having a bank account. Despite the high knowledge among participants, several practical implications should be addressed to combat the disease effectively. These practical implications include a high prevalence of TB, limited access to healthcare, socioeconomic factors, and the emergence of drug-resistant TB strains. In the context of future research on the same topic, we suggest conducting comparative studies among different nations to discern the variances in TB knowledge across the globe.

Antimicrobial resistance is a critical public health concern directly contributing to many deaths globally. Unearthing new protocols to tackle pathogenic microorganisms is vital. Photodynamic inactivation (PDI) is an efficient method for treating cancer and chronic microbial infections. PDI merges light with a photosensitizer to prompt the generation of reactive oxygen species and free radicals, not including O2. These molecules cause a phototoxic reaction and lead to the death of microorganisms. Recent advancements in photodynamic inactivation are focused on the exploration of natural photosensitizers.

In this study, Black Goji Berry Extract (BGBE) was utilized as a photosensitizer at 50 mg/mL concentration. The incubation periods for the extract were 10 and 15 minutes, respectively. Phototoxic reactions were induced using ultraviolet (UV) light, specifically within the 315-400 nm range at an intensity of 8W, for an illumination period of 5 min. This study utilized microbial strains of Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa, and Escherichia coli as test subjects. All the strains went through treatments under these specified conditions. Results were reported after comparing controls and treatments.

Incubating with BGBE for 10-15 min followed by a 5-min black UV illumination induced a phototoxic reaction in bacterial strains such as S. aureus, P. aeruginosa, and E. coli. This resulted in a decrease in bacterial viability by 0.75-0.92 log10 (CFU/mL). No significant difference was observed between the effects on Gram-positive and Gram-negative strains (P>0.05). Moreover, no phototoxic reaction was observed in Candida albicans under similar conditions.

While a sublethal photodynamic reaction was recorded in specific bacterial strains post-photodynamic inactivation utilizing BGBE, BGB exhibits potential as a natural source for innovative photosensitizers.

Precise diagnosis is crucial for implementing suitable and timely treatment strategies, especially when dealing with life-threatening infections like rabies. Rapid diagnosis of rabies is crucial for preventing transmission to the patient’s immediate contacts and medical staff, thereby controlling the further spread of the virus. Conventional methods for detecting rabies are either time-consuming or necessitate expensive equipment operated by trained professionals. This paper presents a novel rapid diagnostic method for rabies. This innovative approach leverages an isothermal reaction within a single platform, offering results within an hour and eliminating the need for specialized equipment. This method uses Cas13a enzyme, buffer, three guide RNAs, and a probe to detect rabies virus RNA using a lateral flow chromatography technique in samples suspected of rabies virus. After doing the test, the results are indicated by the presence of the control (C) and test (T) lines on the strip. Preliminary evaluations demonstrate that this rapid method correlates well with established diagnostic standards, showing promising sensitivity and specificity values.