Avicenna Journal of Clinical Microbiology and Infection
Volume:10 Issue: 3, Sep 2023

Methicillin-resistant Staphylococcus aureus (MRSA) is an established pathogen responsible for hospital-acquired infections (HAIs). Accurate MRSA diagnosis is of paramount importance to facilitate early and effective treatment and to manage its transmission effectively. The primary objective of our study was to determine the precise prevalence of hospital-acquired MRSA (HA-MRSA) in select teaching hospitals in Damascus by detecting the presence of the mecA gene.

One hundred Staphylococcus aureus isolates were collected from various clinical specimens obtained from inpatients admitted to three major teaching hospitals in Damascus, Syria, including Al-Moussat, Al-Assad, and Tishreen Military Hospitals. These patients met the established criteria for HAIs. The isolates were collected between December 2021 and August 2022. Genus and species confirmation were conducted via polymerase chain reaction (PCR), employing the 16SrDNA gene specific to the Staphylococcus genus and the nuc gene specific to S. aureus. Methicillin resistance was assessed using cefoxitin disc diffusion (CDD) in accordance with Clinical and Laboratory Standards Institute (CLSI) recommendations. The presence of the mecA gene was also detected through PCR.

Out of the collected isolates, 67% exhibited resistance to cefoxitin, as determined by the CDD, while 66% were found to be positive for the mecA gene. CDD demonstrated a sensitivity of 100% and a specificity of 97%.

This investigation revealed a notably high incidence of HA-MRSA infections within the teaching hospitals under scrutiny. The CDD method displayed significant sensitivity and specificity, making it a dependable alternative to the mecA PCR for MRSA detection. This finding holds substantial importance for the effective implementation of infection control initiatives and strategies aimed at eradicating MRSA and curtailing its spread within our hospital facilities.

 Pseudomonas aeruginosa, an opportunistic Gram-negative bacterium, is responsible for 10-15% of hospital infections worldwide. The acquisition of resistance genes is one of the important mechanisms that causes the spread of resistance in this bacterium. This study aimed to conduct a phenotypic and genotypic investigation of the blaOXA-4 resistance gene in P. aeruginosa isolated from clinical samples.

 In this study, 110 P. aeruginosa strains were isolated from various clinical samples. The disk diffusion method was applied to reveal the resistance pattern in the isolates. Moreover, the combined disk method was used for the phenotypic analysis of extended-spectrum beta-lactamases (ESBL). Finally, the presence of the blaOXA-4 beta-lactamase gene was analyzed genotypically by polymerase chain reactions (PCR) method.

 The highest sensitivity and resistance of the isolates were related to amikacin (65.45%) and ceftazidime (86.36%), respectively. The phenotypic analysis indicated that 72 isolates (65.45%) of P. aeruginosa are ESBL-producing. Furthermore, the presence of blaOXA-4 was approved genotypically in 33 P. aeruginosa isolates (45.83%).

 This study revealed a high prevalence of antibiotic-resistant isolates of P. aeruginosa in the East Azerbaijan population that may be associated with the presence of the blaOXA-4 gene. However, further studies are necessary to identify other resistant genes in ESBL-producing isolates and other geographical areas with larger sample size.

 OqxB is an efflux pump that has emerged as a factor contributing to antibiotic resistance in Klebsiella pneumoniae. The objective of this study was to investigate the occurrence of AcrAB efflux pump resistance genes in clinical samples of K. pneumoniae and to evaluate the influence of selenium nanoparticles (Se-NPs), loaded with ampicillin, on the expression of the OqxB gene associated with efflux pumps.

 A total of 500 clinical samples were collected from hospitalized patients, and 60 strains of K. pneumoniae were isolated using standard microbiological methods. These strains were then analyzed using phenotypic and polymerase chain reaction (PCR) techniques to detect the frequency of KPSM, MRK, OqxA, and OqxB genes through multiplex PCR. The impact of Se-NPs loaded with ampicillin on the expression of the OqxB resistance gene was investigated using a real-time PCR technique.

 Based on the results of this study, it was found that the KPSM gene is not present in any of the investigated K. pneumoniae isolates. However, the MRK, OqxA, and OqxB genes were detected in 57, 55, and 54 isolates, respectively. The minimum inhibitory concentration (MIC) values for Se-NP and Se-NPs with ampicillin were reported to be 1500 μg/mL and 375 μg/mL, respectively. Notably, the SeNPs with ampicillin could significantly down-regulate the expression of the OqxB gene. These findings demonstrated the potential of Se-NPs as a promising strategy for reducing antibiotic resistance in K. pneumoniae infections.

 The findings emphasize the notable prevalence of drug resistance genes, specifically those associated with efflux pump production, in clinical samples of K. pneumoniae. Remarkably, the utilization of Se nanoparticles loaded with ampicillin demonstrated its efficacy in suppressing the expression of the OqxB gene and enhancing bacterial susceptibility to ampicillin. The results further imply that Se-NPs could serve as a promising avenue for the development of innovative antibacterial agents, aimed at combating antibiotic resistance in K. pneumoniae infections.

Antimicrobials are one of the extremely important categories of drugs for the treatment, control, and prevention of microbial diseases, but the development of drug resistance against clinically used antibacterial agents has increased the demand for the design and synthesis of new drugs. We have previously synthesized new series of 10-substituted-5H-naphtho[1,2-e][1,2,4]triazolo[3,4-b] [1,3,4]thiadiazin derivatives (4a-4f). In this study, we evaluated the antimicrobial activity of these derivatives against some pathogenic microorganisms.

The reaction of 2-bromo-1,4-naphthoquinone with 4-amino-5-aryl-4H-1,2,4-triazole-3- thiols in ethanol at 50 ̊C gave the corresponding 2-[(4-amino-5-aryl-4H-1,2,4-triazol-3 yl)thio] naphthalene-1,4- diones. Moreover, their treatment with EtOH/HCl under reflux conditions produced 10-substituted-5H-naphtho[1,2-e][1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-5- ones through intramolecular cyclization. The well agar diffusion and agar dilution methods were used during the preliminary evaluation of antimicrobial activity for the determination of inhibition zone (IZ) and minimum inhibitory concentration (MIC).

Seven tetracyclic heterocyclic ring systems were produced under reflux conditions. The structures of all the products were identified by their FT-IR, 1H, and 13C NMR spectral data and by elemental analysis. The results revealed that the antibacterial activity of compounds 4a, 4b, 4c, and 4d are higher than that of the others, and compounds 4d, 4a, 4e, and 4f exerted the greatest effect on fungal samples.

All synthesized compounds exhibited promising antibacterial and antifungal activity. In this study, compounds 4a-4g exhibited highly potent antimicrobial activity and acceptable selectivity index against Staphylococcal and Candida infections.

 At present, antibiotic-resistant staphylococci, especially methicillin-resistant strains, are prevalent agents of infections in medical centers and hospitals. The objective of the present investigation was to discern and trace the methicillin resistance gene harbored in two bacterial strains, namely Staphylococcus aureus and Staphylococcus epidermidis, obtained from clinical specimens gathered from patients exhibiting immune system deficiency at Omid hospital located in Isfahan.

 The present investigation was conducted utilizing a descriptive cross-sectional approach. Initially, a total of 70 clinical isolates comprising 35 isolates of S. aureus and 35 isolates of S. epidermidis were obtained from patients who were diagnosed with immunodeficiency and admitted to Omid Hospital located in Isfahan, Iran, from January 2017 to April 2018. After the characterization of the isolates via morphological and biochemical assessments, subsequent evaluation of their antibiotic sensitivity was performed through the utilization of disk diffusion and Epsilometer test (E-test). Then, the identification of the isolates was conducted using the colony PCR method incorporating primers (MCF, MCR, GAIF, and GAIR) and elucidated through molecular analysis.

 In this study, all isolates of S. aureus were resistant to cefoxitin and the MIC of this antibiotic was confirmed using E-test. However, of 35 S. epidermidis isolates, 30 isolates (85.7%) were resistant to oxacillin and 5 isolates (14.3%) were sensitive to oxacillin. According to the molecular findings, out of 35 isolates of methicillin-resistant S. aureus, 4 isolates (11.4%) had the mecA gene, and out of 35 isolates of S. epidermidis, 10 isolates (28.5%) had the mecA gene.

 The present study revealed that precise detection of methicillin resistance in the aforementioned bacterial strains necessitates the employment of both phenotypic and genotypic methods. The frequency of the mecA gene in methicillin-resistant S. aureus (MRSA) was found to be declining. The incidence of methicillin-resistant S. epidermidis (MRSE) is on the rise.

 Chronic diabetic infections commonly involve highly antibiotic-resistant pathogens, such as Staphylococcus aureus and streptococci. This study aimed to assess the impact of zinc (Zn) phthalocyanine incorporated into nanoemulsions on diabetic wound infections.

 Thirty-six adult male rats were divided into control, diabetic wound, diabetic wound infected with S. aureus, and three diabetic wound infected with S. aureus groups, which were treated with laser, medication, and a combination of medication and laser therapy. After the treatment period, wound diameter was measured, and blood samples and wound tissue were collected to evaluate antioxidant factors.

 The results demonstrated a significant reduction in wound diameter in the group treated with both the drug and laser compared to the other groups. The activity of superoxide dismutase (SOD) and glutathione peroxidase (GPX), along with the concentration of glutathione (GSH) in the blood of all groups, exhibited a significant decrease in comparison to the control group. However, the activity of these factors in both blood and tissue showed a noteworthy increase in the rats treated with both the drug and laser, as opposed to diabetic rats infected with S. aureus.

 Photodynamic therapy (PDT) for infectious wounds, employing nanoemulsions containing Zn phthalocyanine, appears to enhance the body’s antioxidant system by eradicating bacteria and, ultimately, expediting wound healing. This approach may be considered a potential candidate for treating antibiotic-resistant infections.

Microsporidia are eukaryotic, single-celled intracellular parasites that can produce spores. Recently, they have been considered one of the opportunistic pathogens causing chronic diseases. There are more than 140 genera and 1200 species of microsporidia. Many human microsporidia are probably of zoonotic origin and are transmitted by contaminated water with animal feces. Given the zoonotic importance of this parasite and its ability to be transmitted from animals to humans, diagnosing and determining the species of parasite would seem essential for health strategies.

Two hundred fecal samples of slaughtered cows were collected from the Jahrom abattoirs from February 2021 to January 2022 and examined by molecular methods, including polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP-PCR).

From the 200 samples examined by PCR, 19 (9.5%) samples tested positive for microsporidia, of which 17 isolates were Enterocytozoon bieneusi and two isolates were Encephalitozoon cuniculi.

The results revealed that microsporidia were present in cow feces. In addition, these findings indicated that cows can be considered a source of contamination for microsporidia. Given that this disease is a zoonosis, it is highly important to pay attention to the presence of this parasite in domestic animals that are in contact with humans. Further studies must be performed in different regions and different animals to understand the epizootiology of the pathogen. Eventually, the wide host range of microsporidia necessitates accurate identification of species and genera in all hosts all over the world.