Advent Of Polymerase Chain Reaction Research Articles

Low-cost conventional PCR techniques enable simultaneous detection of bacterial sexually transmitted infections with enhanced sensitivity and specificity

PurposeNeisseria gonorrhoeae (NG), Chlamydia trachomatis (CT) and Mycoplasma hominis (MH), the three most common treatable bacterial sexually transmitted infections (STIs) worldwide can lead to many complications if remain untreated. Screening of high-risk population with highly sensitive methods will lead to significant improvement in patient outcomes and will prevent downward transmission. The advantages of Polymerase chain reaction (PCR) based assay are not only high sensitivity and specificity, but also detection of multiple organisms in a single reaction which reduce the result turn-around time. The aim of the present study was to evaluate the feasibility of a multiplex PCR assay method targeting 16S rRNA gene for simultaneous detection of NG, CT and MH infection along with their trend and occurrence among high-risk population in Assam, Northeast India. MethodsA cross-sectional study was undertaken, where a total of 200 randomly selected patients from high-risk population were included. After validation of singleplex PCR, Multiplex PCR (M-PCR) was performed along with the traditional culture method for NG. Results & conclusionThe overall agreement of M-PCR with singleplex PCR was very high (100%). The occurrence of STI was found to be very high (101/200; 50.5%). Furthermore, co-infection was detected in 10/200; 5%) individuals. Infection was more common among young individuals (p < 0.05) and males out-numbered females (p < 0.05). The most common organism detected was CT (42/200; 21%) followed by NG (41/200; 20.5%) and MH (20/200; 10%). The M-PCR assay workflow is simple, cost effective and can be used in routine diagnostic laboratories with basic molecular facilities.

Progress in polymerase chain reaction technology and its contribution to the tuberculosis diagnostic ecosystem in India: A mini review

The advent of Polymerase Chain Reaction (PCR) has revolutionized the human molecular diagnostic scenario. Its ability to exponentially generate desired stretch of DNA from chromosomal or complimentary DNA has laid the foundation for sensitive and specific detection of a pathogen or an aberrant stretch of DNA. Importantly, PCR technology has helped generate diagnostic immunity from phenotypic variation of pathogenic targets. The technological evolution of conventional end-point PCR to its real time version further added clinically important features such as enhanced sensitivity and quantification of target DNA molecules. Two important chemistries became prominent in the real-time PCR domain. The intercalating dye-based chemistry comes with convenience, economy and feature such as melt curve analysis but also carries the disadvantage of overestimation of signal due to unwanted signal from primer dimers. Dual labelled probe on the other hand provides unprecedented sensitivity and specificity. Isothermal method of genome nucleic acid amplification has also evolved as a parallel and convenient method of amplification-based detection of nucleic acid targets. Tuberculosis diagnostics has immensely benefitted from these technologies. However, unmet need exists in sputum handling methods and in its adaptation for molecular diagnostics in resource limited settings. Significant dependence for diagnostic needs on the western world is a matter of concern in India. The country will benefit from rapid and indigenous research and development of molecular diagnostic solutions by way of formulating kits for rapid extraction of DNA and RNA from various clinical sources and developing detection technologies that can compete international products in its category. A solution to address sputum transportation, storage and DNA extraction that has enhanced advantages compared to current methods will also be helpful in the efforts to make India free from tuberculosis.

Successful Implementation of Single Urine Polymerase Chain Reaction Test for Evaluating Suspected Cytomegalovirus Infection in Neonates.

Introduction:Overuse of laboratory investigations is viewed as medical waste. In the past, to diagnose congenital cytomegalovirus (CMV) infection, consecutive urine culture samples were obtained. With the advent of polymerase chain reaction (PCR) technology, 1 urine specimen should be enough. We conducted this quality improvement study to look at the effect of a practice change from 3 to 1 urine specimen for PCR testing.Methods:The authors instituted a single PCR urine test for CMV in their neonatal intensive care unit (NICU) in May 2021. We reviewed the data on all the urine CMV PCRs obtained on neonates for 1 year, May 1, 2020, to April 30, 2021 (Epoch 1), and compared it with the data obtained from May 1, 2021, to February 28, 2022 (Epoch 2).Results:A total of 3,612 neonates were born during the study period—1,816 infants were born during Epoch 1 and 1,796 infants during Epoch 2. A total of 97 neonates (5.3%) were evaluated for congenital CMV infection during Epoch 1 and 149 infants (8.2%) during Epoch 2. The single urine sample CMV evaluation rate during Epoch 1 was 53.6% (52 infants out of 97 infants evaluated), which increased to 98.6% in Epoch 2 (147 infants out of 149 infants), P < 0.001. The monthly average cost per infant declined from a mean value of 70.1 dollars to a mean value of 39.5 dollars.Conclusions:We increased the single specimen urine CMV PCR test from 53.6% to 98.6%. The intervention resulted in reducing waste and improving resource utilization.

Screening of specimens by Ziehl-Neelsen staining technique for the diagnosis of extra spinal musculoskeletal tuberculosis: A retrospective study

Introduction: Musculoskeletal tuberculosis is a significant form of extra pulmonary tuberculosis (EPTB) which has substantial consequences if not diagnosed and treated early. Reliable and rapid confirmation of the diagnosis is now possible by advent of Polymerase Chain Reaction (PCR), Cartridge Based Nucleic Acid Amplification Test (CB-NAAT/Gene-Xpert) and radiometric method (BACTEC) However, most of these sensitive technologies are not available at places with constrained resources. Hence, diagnosis of tuberculosis at these places, continues to rely on smear microscopy using Ziehl-Neelsen (ZN) staining. Specificity of ZN staining and microscopy is high, but its overall sensitivity is variable (20-53%). Despite of low sensitivity, it is still an easy, cheap, efficient and accessible tool due to its high specificity. Aim: Aim of the present study was to assess the role of ZN staining in diagnosis of extra-spinal musculoskeletal tuberculosis in resource limited settings. Material and methods: A retrospective study was done from 1st January 2016 to 31st December 2019 on specimens received in microbiology laboratory for ZN staining from clinico-radiologically suspected cases of extra-spinal musculoskeletal tuberculosis. The clinical information of the cases was noted from the Orthopaedics Department case files, while results of ZN microscopy were retrieved from the records maintained in Microbiology Department. Results: Specimens from 95 patients with clinico-radiologically suspected extra-spinal musculoskeletal tuberculosis were examined for Acid Fast Bacillus (AFB) by ZN staining technique. Out of 95 patients; 11 patients (11.58 %) were found to be AFB positive. Conclusion: Owing to low yield percentage of ZN staining in extra spinal musculoskeletal tuberculosis; ZN stain alone cannot be used as a tool for diagnosis of this form of tuberculosis.

Commercial Multiplex Polymerase Chain Reaction versus Periodic Acid-Schiff Testing for the Diagnosis of Onychomycosis.

Diagnosis of onychomycosis using the periodic acid-Schiff (PAS) test for sensitive identification of hyphae and fungal culture for identification of species has become the mainstay for many clinical practices. With the advent of polymerase chain reaction (PCR) testing, physicians can identify a fungal toenail infection quickly with the added benefit of species identification. We compared PAS testing with multiplex PCR testing from a clinical perspective. A total of 209 patients with clinically diagnosed onychomycosis were recruited. A high-resolution picture was taken of the affected hallux nail, and the nail was graded using the Onychomycosis Severity Index. A proximal sample of the affected toenail and subungual debris were obtained and split into two equal samples. One sample was sent for multiplex PCR testing and the other for PAS testing. The results were analyzed and compared. Six patients were excluded due to insufficient sample size for PCR testing. Of the remaining 203 patients, 109 (53.7%) tested positive with PAS, 77 (37.9%) tested positive with PCR. Forty-one patients tested positive with PAS but negative with PCR, and nine tested positive with PCR but negative with PAS. Physicians should continue the practice of using PAS biopsy staining for confirmation of a fungal toenail infection before using oral antifungal therapy. Because multiplex PCR allows species identification, some physicians may elect to perform both tests.

Advances in Neonatal Infections.

Despite continued advances and developments in neonatal medicine, neonatal sepsis is the third leading cause of neonatal mortality and a major public health problem, especially in developing countries. Sepsis accounts for mortality for almost 50% of global children under 5 years of age.Over the past 50 years, there have been many advances in the diagnosis, prevention, and treatment of neonatal infections. The diagnostic advances include better culture techniques that permit more rapid confirmation of the diagnosis, advent of polymerase chain reaction (PCR) to rapidly diagnose viral infections, use of biologic markers indicating evidence of infection, and a better understanding of immunoglobulin markers of infection. From a therapeutic stand point, there have been a variety of antibiotics, antifungals, and antiviral agents, better approaches to prevent sepsis, specific immunotherapy, for example, respiratory syncytial virus (RSV); bundled approach to prevention of deep-line infection and better antibiotic stewardship, leading to earlier discontinuation of antibiotic therapy.Hand hygiene remains the benchmark and gold standard for late-onset sepsis prevention. The challenge has been that each decade, newer resistant bacteria dominate as the cause of sepsis and newer viruses emerge, for example, human immunodeficiency virus, zika virus, and novel coronavirus disease 2019.Future treatment options might include stem cell therapy, other antimicrobial protein and peptides, and targeting of pattern recognition receptors in an effort to prevent and/or treat sepsis in this vulnerable population. Also, the microbiome of premature infants has a smaller proportion of beneficial bacteria and higher numbers of pathogenic bacteria compared with term infants, likely owing to higher frequencies of cesarean sections, antibiotic use, exposure to the hospital environment, and feeding nonhuman milk products. Modifying the microbiome with more mother's milk and shorter duration of antibiotics in noninfected babies should be a goal. KEY POINTS: · Neonatal sepsis remains a leading cause of mortality.. · Challenges include bacterial resistance and newer viruses.. · Future treatments may include newer antibiotics/antivirals and stem cell therapy..

The influence of quality of primers on the formation of primer dimers in PCR

Polymerase chain reaction (PCR) is the most commonly used method for nucleic acids amplification. PCR performance depends on several causes, among which the quality of primers is one of the main determinants affecting specificity, sensitivity and reliability of the reaction. Here, we report on the results of the detailed study devoted to the dimerization of the primers during PCR. The course and specificity of the reaction were studied on the model DNA templates as well as genomic DNA using primers that form amplifiable heterodimeric structures with different thermodynamic stability. It was confirmed that more than two 3′-overlapping nucleotides cause a considerable accumulation of primer dimers. It turned out that the presence of any DNA promotes the formation of dimers even for primers, which do not tend to nonspecific amplification in the absence of DNA. It was shown that dimerization could not be eliminated by commonly used techniques. Even the use of hot-start DNA polymerases does not prevent PD formation if primers with stable 3′-overlapping are employed. Despite several advantages of PCR with abutting primers, their close disposition has no benefits regarding the formation of PD if low-quality primers are utilized.

Bladder cancer genomics.

Until recently, the treatment of bladder cancer, for several years, was limited to surgery and to immunotherapy or chemotherapy. Currently, the extensive analysis of molecular alterations has led to novel treatment approaches. The advent of polymerase chain reaction and genomic hybridization techniques has allowed to investigate alterations involved in bladder cancer at DNA level. By this way, bladder cancers can be classified as papillary or non-papillary based on genetic alterations with activation or mutations in FGFR3 papillary tumors and with inactivation or mutations involving TP53 and RB1 in non-papillary tumors. Recently, the patterns of gene expression allow to differentiate basal and luminal subtypes as reported in breast cancer. In particular, basal cancers are composed of squamous and sarcomatoid pathological findings, while luminal cancers are composed of papillary finding features and genetic mutations (FGFR3). In particular, specific investigative studies demonstrated that luminal cancers are associated with secondary muscle invasive cancer while basal tumors are related to advanced disease since they are often metastatic at diagnosis. Moreover, from therapeutic point of view, different researchers showed that mutations of DNA are related to the sensitivity of bladder cancer while performing cisplatin chemotherapy. In this prospective, the bladder cancer molecular subtyping classification might allow identifying the set of patients who can safely avoid neoadjuvant chemotherapy likely because of the low response to systemic chemotherapy (chemoresistant tumors). In this context, the Cancer Genome Atlas (TCGA) project has improved the knowledge of the molecular targets of invasive urothelial cancers allowing the researchers to propose hypothesis suggesting that agents targeting the genomic alterations may be an effective strategy in managing these cancers, which occur in about 68% of muscle invasive cancers. A future goal will be to combine treatment strategies of invasive bladder cancers according to their genetic mutational load defined by molecular pathology.

Culture-negative periprosthetic joint infections.

Culture-negative periprosthetic joint infections (CN-PJI) pose a significant challenge in terms of diagnosis and management. The reported incidence of CN-PJI is reported to be between 7% and 15%.Fungi and mycobacterium are thought to be responsible for over 85% of such cases with more fastidious bacteria accounting for the rest.With the advent of polymerase chain reaction, mass spectrometry and next generation sequencing, identifying the causative organism(s) may become easier but such techniques are not readily available and are very costly.There are a number of more straightforward and relatively low-cost methods to help surgeons maximize the chances of diagnosing a PJI and identify the organisms responsible.This review article summarizes the main diagnostic tests currently available as well as providing a simple diagnostic clinical algorithm for CN-PJI.Cite this article: EFORT Open Rev 2019;4:585-594. DOI: 10.1302/2058-5241.4.180067

Loop-mediated isothermal amplification (LAMP) and Polymerase Chain Reaction (PCR) as quality assurance tools for Rapid Diagnostic Test (RDT) malaria diagnosis in Northern Namibia.

Malaria cases sometimes go undetected using RDTs due to their inaccurate use, poor storage conditions and failure to detect low parasitaemia (<50parasites/μL). This could result in continuous transmission of malaria and sustenance of parasite reservoirs. Molecular diagnostic tools are more sensitive and specific than RDTs in the detection of plasmodium parasites. However, the Polymerase Chain Reaction (PCR) is not routinely used because equipment and reagents are expensive and requires highly skilled personnel. Loop-mediated isothermal amplification (LAMP) is a relatively new molecular diagnostic tool for malaria with all the advantages of PCR (sensitive and specific) without the mentioned disadvantages. However, it has not been evaluated extensively as a point of care diagnostic in the field. One hundred and fifteen used RDTs were collected from health facilities in Northern Namibia in a blind study and PCR and LAMP were used to determine the presence of Plasmodium DNA. The sensitivities and PPV were 40.91% and 90% respectively for RDTs, 72.73% and 100% respectively for PCR with LAMP as the golden standard. In low malaria transmission settings, LAMP can be also be considered for use as a surveillance tool to detect all sources of malaria and determine proportion of low parasitaemia infections in order to eliminate them.

Preparation of Plasmid DNA by Alkaline Lysis with Sodium Dodecyl Sulfate: Maxipreps.

In recent years, with the advent of polymerase chain reaction and the development of highly efficient methods of cloning and DNA sequencing, the need to prepare large quantities of plasmid vectors and recombinants has greatly diminished. In consequence, this protocol, at one time in common use, has been largely replaced by faster and easier column-based purification methods. In this protocol, plasmid DNA is purified from the cleared bacterial lysate by centrifugation to equilibrium in CsCl gradients containing ethidium bromide. These gradients have an aesthetic quality that justifies the continued presentation of a protocol that in many other respects is an antique. The typical yield of high-copy-number plasmid vectors or of amplified low-copy-number vectors prepared by this method is ∼3-5 µg of DNA/mL of original bacterial culture. The yield of recombinant plasmids containing inserts of foreign DNA is usually slightly lower, depending on the size and nature of the cloned DNA fragment.

Trends in Diagnosis and Control of Bovine Mastitis: A Review

Mastitis (inflammation of mammary gland) is a most devastating disease condition in terms of economic losses occurring throughout the world. The etiological agents may vary from place to place depending on climate; animal species and animal husbandry and include wide variety of gram positive and gram negative bacteria; and fungi. They may be either contagious viz. Staphylococcus aureus; Streptococcus agalactiae or environmental viz. S. dysgalactiae, S. uberis, Corynebacterium bovis and Coagulase negative Staphylococcus. Conventional diagnostic tests viz. California Mastitis Test (CMT); R-mastitest and Mast-O-test methods are applied under field conditions; whereas somatic cell count and Bulk Tank Somatic Cell Count (BTSCC) are useful for early mastitis detection and detection of sub clinical or chronic mastitis respectively. In vitro culture based diagnosis require further study as they can detect only viable cells. The advent of Polymerase Chain Reaction (PCR) technology along with its various versions like multiplex and real time PCR has improved the rapidity and sensitivity of diagnosis. Circulating micro RNA (miRNA) based diagnosis; immune assay and proteomics based detection along with biochips and biosensors prove to be asset to diagnosticians for advanced diagnosis of this economically important condition. Improvement of milking hygiene; implementation of post-milking teat disinfection; regular control of the milking equipments; implementation of milking order; Improvement of bedding material are the general measures to prevent new cases of mastitis. The use of antibiotics (intramammary infusions; bacteriocins) and herbs (Terminalia spp.) are important for prophylaxis and therapeutics. Vaccines viz. cell based; Recombinant (staphylococcal enterotoxin type C mutant) or chimeric (pauA); live (S. uberis 0140J stain based) and bacterial surface extract based; DNA-based and DNA-protein based have greatly aided in management of bovine mastitis. Quorum sensing and disease resistant breeding using novel biomarkers viz. toll like receptors (TLR) 2 and 4, interleukin (IL) 8; breast cancer type 1 susceptibility protein (BRCA1) and calcium channel voltage-dependent alpha 2/delta sub unit 1 (CACNA2D1) are also indispensable. This mini review gives an overview of all these different aspects that act as trend setters as far as the diagnosis and control of bovine mastitis is concerned to help the diagnosticians; epidemiologists and researchers not to remain ignorant about this grave condition.

English

The timely detection and appropriate identification of causal agents associated with disease of crop plants or seeds are considered to be the most important issue in formulating the management strategies for plant diseases. This is particularly important for plant diseases of a bacterial nature, where disease-free planting materials is the only effective way to restrict the disease. The detection of bacterial pathogens still largely depends on cultural, morphological and biochemical properties. The protocol requires skilled taxonomical expertise and is also time and labor intensive. Moreover, it cannot discriminate between closely related strains of same bacterial pathogens. With the advent of polymerase chain reaction (PCR), nucleic acid based techniques have made the diagnostic procedures for plant pathogens, including bacteria, easier than the conventional approaches. The wide acceptability of nucleic acid based techniques is due to them being more sensitive, more accurate, more specific, and much faster than conventional techniques. The serology-based diagnoses are very often preferred over nucleo-based techniques as they are more user-friendly and less cumbersome, besides being sensitive, accurate, specific, and much faster than conventional techniques. This review critically analyzes the recent developments and scope of various nucleic acid- and serology-based techniques for the diagnosis of bacterial plant pathogens. &nbsp; Key words:&nbsp;Bacterial pathogens,&nbsp;diagnosis, detection.

Amplified fragment length polymorphism: an adept technique for genome mapping, genetic differentiation, and intraspecific variation in protozoan parasites

With the advent of polymerase chain reaction (PCR), genetic markers are now accessible for all organisms, including parasites. Amplified fragment length polymorphism (AFLP) is a PCR-based marker for the rapid screening of genetic diversity and intraspecific variation. It is a potent fingerprinting technique for genomic DNAs of any origin or complexity and rapidly generates a number of highly replicable markers that allow high-resolution genotyping. AFLPs are convenient and reliable in comparison to other markers like random amplified polymorphic DNA, restriction fragment length polymorphism, and simple sequence repeat in terms of time and cost efficiency, reproducibility, and resolution as it does not require template DNA sequencing. In addition, AFLP essentially probes the entire genome at random, without prior sequence knowledge. So, AFLP markers have emerged as an advance type of genetic marker with broad application in genomic mapping, population genetics, and DNA fingerprinting and are ideally suited as screening tool for molecular markers linked with biological and clinical traits. This review describes the AFLP procedure and its applications and overview in the fingerprinting of a genome, which has been currently used in parasite genome research. We outline the AFLP procedure adapted for Leishmania genome study and discuss the benefits of AFLPs for assessing genetic variation and genome mapping over other existing molecular techniques. We highlight the possible use of AFLPs as genetic markers with its broad application in parasitological research because it allows random screening of the entire genome for linkage with genetic and clinical properties of the parasite. In this review, we have taken a pragmatic approach on the study of AFLP for genome mapping and polymorphism in protozoan parasites and conclude that AFLP is a very useful tool.

Polymerase Chain Reaction-Based Detection of Pneumocystis jirovecii in Bronchoalveolar Lavage Fluid for the Diagnosis of Pneumocystis Pneumonia

IntroductionThe diagnosis of pneumocystis pneumonia (PCP) in non-human immunodeficiency virus (HIV)-infected immunocompromised patients is notoriously difficult. The recent advent of polymerase chain reaction (PCR)-based detection systems, based on the identification of single fungal genes, has markedly improved diagnostic accuracy in this ominous disease. In an attempt to further improve diagnostic yield, the authors used a PCR-based detection system for Pneumocystis jirovecii, based on targeting 3 distinct genes. MethodsDuring the 4-year period (January 2005 to January 2009), all consecutive immunocompromised patients suspected of having PCP in the differential diagnosis underwent bronchoscopy with bronchoalveolar lavage sampling for the evaluation of the etiology of pulmonary infiltrates. Bronchoalveolar fluid was tested for the presence of a wide variety of possible etiological microorganisms. ResultsIn a cohort of 214 immunocompromised patients (of which 198 were non-HIV immunocompromised patients) who underwent bronchoscopy with bronchoalveolar lavage for evaluation of pulmonary infiltrates, PCR correctly diagnosed PCP in 75% (42/56) compared with 14% (8/56) diagnosed by traditional stains, and increased diagnostic yield 5.4-fold. ConclusionsGiven the absence of a sensitive gold standard, this study demonstrates the usefulness of a multigene PCR-based detection of Pneumocystis jirovecii DNA for supporting the clinical diagnosis of PCP, with high sensitivity and negative predictive value rates compared with direct stains, especially in non-HIV immunocompromised patients.

Are molecular data supplanting morphological data in modern phylogenetic studies?

Morphological data have long served as major sources ofinformation for inferring phylogenetic relationships amongtaxa. With the advent of polymerase chain reaction and modernmolecular approaches to phylogenetics, DNA has become amajor source for phylogenetic inference. Combined analyses ofmolecular and morphological (CAMM) data are not unusual.Studies examining the relative utility of morphological andmolecular data derived from plants and animal groups havebeen performed (e.g. Sanderson & Donoghue, 1989), but theresults of this research were limited by the relative noveltyof molecular data to phylogenetics at the time. Differencesof opinions exist among systematic biologists concerning theutility of morphological data (Scotland

Genetic fingerprinting: Advancing the frontiers of crop biology research

Genetic fingerprinting is one of the DNA-based techniques that have permeated a wide gamut of biological research, beginning with forensic biology and medicine and now extending to agriculture. The advent of polymerase chain reaction (PCR) ushered a revolutionary approach in producing genetic fingerprints, supplanting hybridization-based techniques. PCR-based methods can be accomplished using either arbitrary markers of unknown location in the genome or those markers that target specific genome sites. Among agricultural crops, rice and maize are the most intensively characterized for DNA markers. At present, genetic fingerprinting has also been applied in many aspects of crop biology, such as taxonomy and phylogeny, diversity analysis, hybridity testing, gene mapping, molecular breeding, and somaclonal variation. This paper describes genetic fingerprinting technology and discusses its applications in the major crops of the Philippines, highlighting the progress made by Filipino scientists.

Selected Antimicrobial Resistance during Composting of Manure from Cattle Administered Sub‐Therapeutic Antimicrobials

Composting is being increasingly employed for the recycling of nutrients in manure from the livestock industry. However, composting manure from animals fed antimicrobials has not been well characterized. In this study, compost windrows were prepared using manure collected from cattle (Bos Taurus L.) fed tylosin (TY), chlortetracycline-sulphamethazine (TS), and control cattle (no antimicrobials). The objectives of the 18-wk trial were to quantitatively assess the survival of total E. coli, E. coli resistant to ampicillin (Amp(r)) and tetracycline (Tet(r)), and select tetracycline (tet) and erythromycin resistance methylase (erm) genes. We found that while compost windrows did not reach the recommended temperature of 55 degrees C for 15 d, composting reduced high initial levels of total, Amp(r), and Tet(r) E. coli as early as Week 2. A significant antimicrobial effect on total (P = 0.04) and Amp(r) (P = 0.03) E. coli was observed. Significant antimicrobial x time interactions were observed from Week 0 to Week 3 (Total E. coli: P = 0.04; Amp(r): P = 0.02; Tet(r): P = <0.001). Low absolute abundance of tet and erm genes (<10(6) copies g(-1)) was found and the resistance genes displayed different dynamics; tet(A,C) and erm(A) increased marginally at Week 11 relative to Week 0 and 5 and the remaining genes (tet(G), RPP tet, erm(B), erm(C), erm(F), erm(T), and erm(X)) decreased for most time points and treatments. These results indicate that even though composting reduces antimicrobial resistant E. coli, tet and erm genes could still be detected. Our experiments reiterate advantages of polymerase chain reaction (PCR)-based quantitative assays over cultivation-based methods for the rapid identification of composting effectiveness in eliminating resistance genes before land application.

Solitary Neck Swelling of 2-Week Duration in a 27-Year-Old Woman

Solitary Neck Swelling of 2-Week Duration in a 27-Year-Old Woman

45-Year-Old Woman With Recurrent Headache and Photophobia

45-Year-Old Woman With Recurrent Headache and Photophobia