Archives of Clinical Infectious Diseases
Volume:14 Issue: 2, Apr 2019

Considerable controversy surrounds the use of biocides in an ever-growing range of consumer products and the eventuality that their indiscriminate consumption might decrease biocide effectiveness and modify susceptibilities to antibiotics. Several line of evidence suggest that exposure to biocides may cause increased antibiotic resistance. Thus, we reviewed the common resistance strategies of bacteria against both biocides and antibiotics. Several publications have explained the cell target of biocides and the various mechanisms used by bacterial cells to escape biocides’ toxic activity. Here, we briefly reviewed the commonly used resistance mechanisms of bacteria against both biocides and antibiotics. Biocides could act on multiple sites in microorganisms and cause resistance by non-specific means. We mentioned several mechanisms such as efflux pumps, cell wall changes to the reduction of permeability, genetic linkage with both biocide resistance genes and antibiotic resistance genes, the penetration/uptake changes in envelope by passive diffusion, effect on the integrity and morphology of membrane, and effects on diverse key steps of bacterial metabolism. Along with this toxic effect and stress, bacterial cells express some similar defense strategies that can overlap the main functions conferring resistance versus structurally non-related molecules. It can be stated that healthcare-associated, community-acquired, and nosocomial infections should be surveyed annually. Since biocide-antibiotic cross-resistance can be conferred by a number of distinct mechanisms, it is important to evaluate the propensity of a bacterium to express these mechanisms. Advances in modern genetic methods and the development of an assay using specific chemosensitizers or markers might allow the development of routine tests to identify resistance mechanisms. Further studies are needed to establish a correlation between biocide exposure (s) and development of antibiotic resistance, but the number of studies in the clinical or environmental settings is limited.

The incidence of invasive fungal infections (IFI) caused by unusual pathogens is on the rise, partly driven by the increased population of immunocompromised patients. The emerging multidrug-resistant yeast pathogen Candida auris (auris means ear in Latin) has been a source of concern as an agent of healthcare-associated infections. Some strains of Candida auris isolates are multi-resistant to the main classes of conventional antifungal drugs, and their identification using standard laboratory protocols has been proved difficult. Many of these strains have been misidentified to be other yeasts such as Rhodotorula glutinis, Saccharomyces cerevisiae or Candida haemulonii. In fact, specialized laboratory procedures are required for their proper identification such as molecular techniques based on sequencing the D1-D2 region of the 28 s rDNA or matrix-assisted laser desorption ionization time of flight (MALDI-TOF). Misidentification might result in inappropriate treatment. Furthermore, C. auris has the tendency to cause outbreaks in healthcare settings as has already been reported from several countries worldwide. Finally, it is important to emphasize that C. auris is emerging as an important nosocomial pathogen in many parts of the world, which highlights the need for developing rapid and reproducible methods for its identification and typing.

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease. In patients with lung tissue damage, fungal colonization leads to persistent infection. It is expected for there to be an association between fungal agents and etiology of IPF. The aim of this study was to investigate the prevalence and molecular identification of fungal species isolated from IPF patients for the first time in Iran. Also, in vitro anti-fungal susceptibility testing of isolates was demonstrated. Forty nasopharyngeal (NP) swabs or bronchoalveolar lavage (BAL) samples were obtained from Iranian patients with IPF, who were diagnosed by a sophisticated practitioner from year 2015 to 2016 (Tehran, Iran). Direct examination of samples was carried out using hydroxide potassium (KOH) for detection of fungal elements. The specimens were cultured on Sabauroud Dextrose Agar (SDA) medium. Conventional methods, including polymerase chain reaction (PCR) and sequencing, were carried out for identification of fungal species. Indeed, antifungal susceptibility testing of yeast isolates was conducted according to Clinical Laboratory Standards Institute (CLSI M27- S3 and S4) protocol. The data was analysed using SPSS sofware version 20. Of 40 IPF patients, 22 (55%) were female and 18 (45%) were male. Seven (17.5%) of IPF patients were positive for fungal species as follows; four (10%) Candida albicans (C. albicans), two (5%) Candida glabrata (C. glabrata), and one (2.5%) Aspergillus fumigatus (A. fumigatus) were identified using the culture and PCR technique. A significant correlation was found between C. albicans colonization in upper respiratory system tract and presence of underlying disease in IPF patients (P < 0.05). Antifungal susceptibility testing showed that all C. albicans isolates were resistant to itraconazole, whereas three (75%) C. albicans were resistant to amphoterecin B. It was found that three (75%) and one (25%) C. albicans isolate were susceptible dose dependantly and resistant to fluconazole, respectively. Morever, C. glabrata isolates were resistant to fluconazole, itraconazole, and amphotricin B. Taken together, fungal species were detected in 17.5% of IPF patients. Resistance of Candida species to antifungal agents is growing, therefore isolation, identification, and antifungal susceptibility testing of fungal elements in IPF patients are necessary for appropriate treatment. However, determining an association between the fungal agents and devasting form of pulmonary fibrosis requires further investigation in the future.

Acinetobacter baumannii is capable of forming biofilms that may be responsible for the survival of this pathogen in the hospital environment as well as antibiotic resistance. In this study, considering the importance of genes bap, blaPER-1, and csuE in the formation of biofilms and resistance to antimicrobial drugs, we aimed to investigate the frequency of these genes and also the relationship between these genes and the biofilm formation. One hundred and eighteen clinical strains of the A. baumannii were collected and identified using standard microbiological methods. Antibiotic susceptibility was evaluated by microdilution broth and disk diffusion methods according to the Clinical and Laboratory Standards Institute (CLSI). Biofilm formation assay was performed by microtiter plate method. Then the bap, blaPER-1, and csuE genes were detected by PCR. The rate of XDR and MDR were 16.1% and 83.9%, respectively. Moreover, 9 (7.6%) isolates were resistant to colistin. The results of biofilm formation revealed that 32 (27.1%), 33 (28.0%), 37 (31.4%), and 16 (13.6%) of the isolates had non-biofilm, weak, moderate, and strong activities, respectively. The association between the formation of biofilm and amikacin resistance was found (P < 0.05). In the isolates, the frequencies of bap, blaPER-1, and csuE genes were 70.3%, 54.2%, and 93.2%, respectively. Statistical analysis showed a significant correlation between the frequency of blaPER-1 and bap genes and the ability to form biofilms (P < 0.05). This study shows the high tendency among the clinical isolates of A. baumannii to form a biofilm. It also shows the correlation between the presence of blaPER-1 and bap genes with the capacity of biofilm formation. Moreover, the majority (92.4%) of the A. baumannii isolates from Isfahan were susceptible to colistin. Therefore, providing new and effective strategies is essential for the prevention and treatment of infections caused by biofilm-forming A. baumannii strains.

Staphylococci are important pathogenic bacteria responsible for a range of diseases in humans. Hence, detection of Staphylococcus aureus from coagulase-negative staphylococci (CoNS) is essential in various infections. The aim of this study was to design a melting curve analysis (MCA) assay based on Multiplex Real-Time PCR for rapid detection of staphylococci and antibiotic resistance. The current study used standard strains of positive and negative coagulase staphylococci. As the first step, serial dilutions were prepared with ratios of 108 to 101 cfu/mL based on standard bacterial concentration with 0.5 McFarland and the results were illustrated in dedicated melting curves. All melting curves of gene amplification had an equal melting point. In all dilutions, the observed melting temperatures shown in the melting curves of gene amplification were equal to 83.79°C for ITS-gene, 74.2°C for phop gene, 76.49°C for sap-gene, 78.2°C for mvaA gene, 79.57°C for 16srRNA-gene, 74.83°C for mupA gene, and 76.6°C for mecA gene. The MCA based on real time-PCR for identifying staphylococcal species and antibiotic resistance is a highly effective method with high sensitivity and specificity.

Evaluation of severity, complications, and risk of death due to community-acquired pneumonia (CAP) plays a major role in making decisions about treatment. Biomarkers are one of the tools used to diagnose the disease. The current study aimed at evaluating the relationship between C-reactive protein (CRP) serum level and outcomes of CAP in affected patients. CRP serum level was measured on the 1st and 3rd days of admission in 73 patients. Chest X-ray was taken and CURB-65 (confusion, blood urea > 42.8 mg/dL, respiratory rate > 30/minute, blood pressure < 90/60 mmHg, age > 65 years) criteria was also applied. The patients were followed up for 30 days and evaluated for admission to intensive care unit (ICU), need for mechanical ventilation, inotropic support, incidence of pleural effusion, empyema, lung abscess, and death. CRP level on the 3rd day of admission had a significant and direct relationship with the incidence of complications and death in patients. There were no significant relationship between CURB-65 score and mean CRP level on admission. There was a significant relationship between mean CRP level on 3rd day and CURB-65 score. Clinical status had a significant relationship with mean CRP levels on the 1st and 3rd days of admission. Considering a cutoff point of 25 for CRP level on the 3rd day of admission, there was a significant difference between two groups in terms of mortality rate and CURB-65 scores. The results of the current study showed that elevated CRP level on the 3rd day of admission could be a sign of increased risk of complications and severity of the disease as well as death. It can be used as a factor for the prognosis of complications and outcomes.

Interleukin-17A (IL-17A) gene can be a potential candidate gene implicated in visceral leishmaniasis (VL), a disease caused by an infection with Leishmania parasite. The aim of this study was to explore whether there is an association between IL-17A polymorphisms and VL in the Iranian population. A total of 202 participants (55 VL patients and 125 healthy controls) were investigated in the present case-control study. Genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The frequencies of IL-17A rs3819024, rs3819025, and rs8193038 A alleles, and haplotype AGAG were significantly higher in the controls than patients (P = 0.0006, 0.017, 0.0003 and 0.001, respectively), while IL-17A rs3748067 A allele distribution was higher in patients than controls (P = 0.00004). Also, the frequencies of AA genotypes of rs3819024, rs3819025 and rs8193038 were higher in the controls (P = 0.0048, 0.014, and 0.018, respectively) while rs3748067 AA genotype was of greater distribution in the patients (P = 0.000048). The findings highlighted the role of IL-17A in the pathogenesis of the VL in humans.

Protozoa and helminthic parasites are the most common opportunistic parasites infections associated with the gastrointestinal tract in immunocompromised patients. There have been very few studies addressing this issue in central Iran and our purpose was to determine the frequency of the intestinal parasitic infections (IPIs) in different groups of immunocompromised patients admitted to the referral hospitals in Isfahan, Iran. A cross-sectional study was performed on 204 immunocompromised patients (HIV/AIDS, lymphoma, leukemia, renal transplant and other transplants) between 2015 - 2016. Stool samples were analyzed for intestinal parasites using direct-smear, formol-ether concentration method and modified Ziehl-Neelsen staining techniques. The total rate of any parasites was 43.1% (88/204) in the patients. The prevalence of parasites was 32.7% (17/52), 39.6% (19/48), 46.2% (18/39), 56.0% (28/50), and 40.0% (6/15) in HIV/AIDS, lymphoma, leukemia, renal transplant recipients, and the other transplant recipients, respectively. Blastocystis hominis (30.4%), Cryptosporidium spp. (3.9%), Entamoeba coli (6.3%), Giardia lamblia cyst (5.4%), Endolimax nana (2%), ova of Fasciola spp. (0.5%) and Dicrocoelium dendriticum (0.9%) were the overall parasites that were found in this study. The most common parasites which were related to diarrhea were Blastocystis hominis and Cryptosporidium spp. The parasitic infection was significantly higher in urban patients and females (P < 0.05). Nevertheless, no significant relationship was observed between the prevalence of parasitic infections and age, occupation and level of education. Our findings highlighted that IPIs are a common health problem among immunocompromised patients, in central Iran. Therefore these patients should be screened routinely for intestinal parasites and treated promptly.

Rabies virus (RV) is one of the most dangerous zoonotic disease and major public health problems in most of the world, especially underdeveloped countries. Rabies is preventable by proper vaccination, even shortly after exposure. Today, it seems a fast, sensitive, and reliable rabies diagnostic method is required, which might reduce the financial burden of inappropriate diagnosis. The aim of this study was to develop and validate two molecular techniques, including heminested RT-PCR and qRT-PCR assays, for comprehensive detection of rabies virus in the suspected rabid brain and saliva samples. In this study, we developed qRT-PCR as a fast, sensitive, and specific method for rapid detection of rabies virus in brain and saliva samples. Also, the sensitivity and specificity of the method were compared with heminested RT-PCR test and direct fluorescent antibody (dFA) as a serologic gold standard method of World Health Organization (WHO) and MIT (mouse inoculation test) as a confirmatory test. A combination of compatible primers based on RNA-dependent RNA polymerase (L) gene of the Pasteur virus fixed strain (PV) (accession number. M13215) was used for developing the qRT-PCR assay. Primer and probes were designed according to other Iran circulating viruses genomes that were available in public databases (GenBank). The clinical sensitivities of qRT-PCR and heminested RT-PCR methods were determined 97.14% and 94.3%, respectively. In addition, the clinical specificities of qRT-PCR and heminested RT-PCR methods were determined 93.75% and 88.24%, respectively. Also, the analytical sensitivities of qRT-PCR and heminested RT-PCR methods were about 5 × 102 and 5 × 103 FFU/mL, respectively. In this study, qRT-PCR assay as a diagnostic molecular method with high sensitivity and specificity was developed for the detection of the rabies virus genome in both brain and saliva samples. Therefore, this rapid, accurate, and cost-effective detection and quantification method may be used as an investigative tool, which can be valid for detection of target viral genome in the research and diagnosis field.

Corynebacterium urealyticum is a Gram-positive, lipophilic, multidrug resistant, and urease positive microorganism with diphtheroid morphology. C. urealyticum causes several diseases such as urinary tract infection, chronic urological disease, urinary tract infections, and bacteremia in immunocompromised individuals. This study reports a rare case with nosocomial infection and hematuria caused by multidrug-resistant C. urealyticum after prostate cancer surgery.