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OBJECTIVES: Biofilm formation is one of the important features of Staphylococcus epidermidis, particularly in nosocomial infections. We aimed to investigate the biofilm production by phenotypic methods and the presence of ica genes in S epidermidis. METHODS: A total of 41 S epidermidis isolates were recovered from different clinical specimens. Biofilm formation was evaluated by microtiter plate, tube method and Congo red agar method. The presence of icaA and icaD genes was investigated by PCR. Validity of methods (sensitivity and specificity), and metrics for test performance (positive/negative predictive value, and positive/negative likelihood ratio) were determined. RESULTS: By both microtiter plate and tube method, 53.6% of S epidermidis isolates were able to produce biofilm, whilst only 24.4% of isolates provided a biofilm phenotype on Congo red agar plates. icaA and icaD genes were found in 100% and 95.1% of isolates, respectively. Biofilm phenotypes accounted for 4.8% by microtiter plate assay, despite the absence of the ica gene. Congo red agar and PCR exhibited a lower sensitivity (18% and 45.5%, respectively) for identifying the biofilm phenotype in comparison to microtiter plate. CONCLUSION: The microtiter plate method remains generally a better tool to screen biofilm production in S epidermidis. In addition, the ability of S epidermidis to form biofilm is not always dependent on the presence of ica genes, highlighting the importance of ica-independent mechanisms of biofilm formation. The use of reliable methods to specifically detect biofilms can be helpful to treat the patients affected by such problematic bacteria.
Subject(s)
Humans , Agar , Bacteria , Biofilms , Congo Red , Cross Infection , Methods , Operon , Phenotype , Polymerase Chain Reaction , Staphylococcus epidermidis , StaphylococcusABSTRACT
Background: Detection and quantification of human Papillomavirus [HPV] genome in oral carcinoma play an important role in diagnosis, as well as implications for progression of disease
Methods: We evaluated tissues from 50 esopharyngeal cancers collected from different regions of Iran for HPV E6 using the two type-specific primers sets. E6 gene of HPV genotypes was amplified by specific primers. The sensitivity of PCR assay was analyzed and determined using HPV-DNA-containing plasmids. Real-time PCR was utilized to determine the prevalence and HPV viral load in patients with oral cavity squamous cell carcinoma
Results: Eighteen [36%] specimens were positive for HPV. Among the 18 positive specimens, 10 showed HPV-18 [55.55%], and 8 specimens were positive for HPV-11 [44.44%]. Of the 18 infected specimens, 6 [33.32%] and 12 [66.65%] were identified as high-titer and low-titer viral load, respectively
Conclusions: The PCR-based assay, developed in the current study, could be used for HPV detection, quantification, and genotyping in epidemiological and clinical studies
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Objectives: Reduced biocide susceptibility in Staphylococci is associated with various antiseptic resistance genes encoding efflux systems. Our aim was to determine the susceptibility to three disinfectant agents, including benzalkonium chloride [BAC], benzethonium chloride [BZT], and chlorhexidine digluconate [CHDG] among clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococci [CoNS]
Methods: The minimum inhibitory concentration [MIC] of 60 methicillin-resistant S. aureus [MRSA], 54 methicillin-sensitive S. aureus [MSSA] and 51 CoNS isolates from a single hospital to three biocidal agents [BAC, BZT, and CHDG] was determined. Biocide resistance genes [qacA/B, smr, qacG, qacH, qacJ, and norA] were analyzed by the polymerase chain reaction assay
Results: All isolates had MICs for BAC and BZT from 0.25 to 8 microg/mL, and for CHDG from 0.5 to 64 microg/mL. qacA/B was the most common biocide resistance gene among all 165 Staphylococcus isolates [76; 46%], which comprised 38 [63.3%] MRSA, 14 [25.9%] MSSA, and 24 [47%] CoNS. Eleven [6.7%] and 24 [14.5%] isolates among the 165 Staphylococci carried smr and norA genes, respectively. In contrast, other resistance genes such as qacG, qacH, and qacJ were absent in all Staphylococci studied. The qacA/B and smr genes were detected concomitantly in 3% of isolates, and 23.6% strains of the total 165 Staphylococcus isolates were negative for each studied gene
Conclusions: The carriage of several biocide resistance genes, including qacA/B, smr, and norA, alone or concurrently, is associated with reduced susceptibility. Use of antiseptics may select for antibiotic-resistant strains and assist their survival in the healthcare environment
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Objective: To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification. Methods: A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates.Results:activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA- positive in the PCR assay. Among antibiotics used in our study, penicillin showed the least anti-staphylococcal Conclusions: This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic.
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<p><b>OBJECTIVE</b>To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification.</p><p><b>METHODS</b>A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates.</p><p><b>RESULTS</b>Among antibiotics used in our study, penicillin showed the least anti-staphylococcal activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA- positive in the PCR assay.</p><p><b>CONCLUSIONS</b>This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic.</p>
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BACKGROUND: Acinetobacter baumannii is one of the most important pathogens capable of colonization in burn patients, leading to drug-resistant wound infections. This study evaluated the distribution of the AdeABC efflux system genes and their relationship to ciprofloxacin resistance in A. baumannii isolates collected from burn patients. METHODS: A total of 68 A. baumannii clinical strains were isolated from patients hospitalized in Motahari Burns Center in Tehran, Iran. Ciprofloxacin susceptibility was tested by the disk diffusion and agar dilution methods. PCR amplification of the adeRS-adeB drug efflux genes was performed for all resistant and susceptible isolates. To assess the role of the drug efflux pump in ciprofloxacin susceptibility, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) was used as an efflux pump inhibitor (EPI). RESULTS: Approximately 95.6% of the Acinetobacter isolates were resistant to ciprofloxacin, with minimum inhibitory concentration (MIC) values ranging from 4 to > or =128 microg/mL. The susceptibility of 86.1% of the resistant isolates increased by factors of 2 to 64 in the presence of CCCP. All resistant isolates were positive for the adeRS-adeB genes, and 73.2% of them had mutations in the AdeRS regulatory system. CONCLUSIONS: The results showed that AdeABC genes are common in A. baumannii, which might be associated with ciprofloxacin non-susceptibility, as indicated by the observed linkage to the presence of the genes essential for the activity of the AdeABC, several single mutations occurring in the adeRS regulatory system, and an increase of ciprofloxacin susceptibility in the presence of a CCCP EPI.