Effects and Mechanism of Particulate Matter on Tendon Healing Based on Integrated Analysis of DNA Methylation and RNA Sequencing Data in a Rat Model.

Exposure to particulate matter (PM) has been linked with the severity of various diseases. To date, there is no study on the relationship between PM exposure and tendon healing. Open Achilles tenotomy of 20 rats was performed. The animals were divided into two groups according to exposure to PM: a PM group and a non-PM group. After 6 weeks of PM exposure, the harvest and investigations of lungs, blood samples, and Achilles tendons were performed. Compared to the non-PM group, the white blood cell count and tumor necrosis factor-alpha expression in the PM group were significantly higher. The Achilles tendons in PM group showed significantly increased inflammatory outcomes. A TEM analysis showed reduced collagen fibrils in the PM group. A biomechanical analysis demonstrated that the load to failure value was lower in the PM group. An upregulation of the gene encoding cyclic AMP response element-binding protein (CREB) was detected in the PM group by an integrated analysis of DNA methylation and RNA sequencing data, as confirmed via a Western blot analysis showing significantly elevated levels of phosphorylated CREB. In summary, PM exposure caused a deleterious effect on tendon healing. The molecular data indicate that the action mechanism of PM may be associated with upregulated CREB signaling.

The E3 ubiquitin ligase CHIP selectively regulates mutant epidermal growth factor receptor by ubiquitination and degradation.

Somatic mutation in the tyrosine kinase domain of epidermal growth factor receptor (EGFR) is a decisive factor for the therapeutic response to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in lung adenocarcinoma. The stability of mutant EGFR is maintained by various regulators, including heat shock protein 90 (Hsp90). The C terminus of Hsc70-interacting protein (CHIP) is a Hsp70/Hsp90 co-chaperone and exhibits E3 ubiquitin ligase activity. The high-affinity Hsp90-CHIP complex recognizes and selectively regulates their client proteins. CHIP also works with its own E3 ligase activity independently of Hsp70/Hsp90. Here, we investigated the role of CHIP in regulating EGFR in lung adenocarcinoma and also evaluated the specificity of CHIP's effects on mutant EGFR. In HEK 293T cells transfected with either WT EGFR or EGFR mutants, the overexpression of CHIP selectively decreased the expression of certain EGFR mutants (G719S, L747_E749del A750P and L858R) but not WT EGFR. In a pull-down assay, CHIP selectively interacted with EGFR mutants and simultaneously induced their ubiquitination and proteasomal degradation. The expressions of mutant EGFR in PC9 and H1975 were diminished by CHIP, while the expression of WT EGFR in A549 was nearly not affected. In addition, CHIP overexpression inhibited cell proliferation and xenograft's tumor growth of EGFR mutant cell lines, but not WT EGFR cell lines. EGFR mutant specific ubiquitination by CHIP may provide a crucial regulating mechanism for EGFR in lung adenocarcinoma. Our results suggest that CHIP can be novel therapeutic target for overcoming the EGFR TKI resistance.

Hippo pathway effector YAP inhibition restores the sensitivity of EGFR-TKI in lung adenocarcinoma having primary or acquired EGFR-TKI resistance.

The efficacy of EGFR-tyrosine kinase inhibitors (TKIs) is significantly limited by various resistance mechanisms to those drugs. The resistance to EGFR-TKI is largely divided by two classes; acquired resistance after EGFR-TKI treatment, and primary resistance marked by cancer cell's dependence on other oncogene, such as KRAS. YAP has emerged as critical oncogene in conferring drug resistance against targeted therapy. In this study, we evaluated the role of YAP in primary and acquired EGFR-TKI resistance using gefitinib-resistant A549 and PC9 cells and their parental cell lines. Our study revealed that EGFR-TKI resistance is associated with enhanced YAP activity. Notably, YAP activation was independent of the Hippo pathway. We confirmed that AXL is a downstream target of YAP that confers EGFR-TKI resistance. And our results showed that YAP can induce ERK activation in lung adenocarcinoma. The combination of YAP inhibition with EGFR-TKI overcomes primary and acquired EGFR-TKI resistance. We also found increased YAP expression in human lung cancer after acquiring EGFR-TKI resistance. Collectively, we suggest a novel EGFR-TKI resistance mechanism involving YAP activation and suggest targeting YAP and EGFR simultaneously may be a breakthrough treatment of primary and acquired EGFR-TKI resistant lung cancer.

KRAS discordance between primary and recurrent tumors after radical resection of colorectal cancers.

BACKGROUND: Although KRAS shows high concordance between primary and metastatic colorectal cancers, recent studies have reported discordance and intra-tumoral heterogeneity. To evaluate KRAS concordance between primary colorectal cancers and recurrent tumors after radical resection, we performed this study. METHODS: Between January 2007 and August 2013, among patients underwent radical resection for primary colorectal cancers and tissue sampling of recurred tumors including resection or biopsy, 74 patients whose both primary and recurred tumor tissues were available for KRAS analysis were enrolled. The clinical and pathologic data were retrospectively revised and KRAS analyses were performed. RESULTS: The patients with initial M1 stage showed significantly higher KRAS discordance rate (54.5%). The KRAS concordance rate was 79.7% (n = 59). Forty-two patients (56.8%) showed the wild-to-wild type and 17 (22.9%) showed the mutant-to-mutant type. The discordance rate was 20.3% (n = 15). Eight patients (10.8%) showed the wild-to-mutant type, and 7 (9.5%) showed the mutant-to-wild type. Among 15 discordance cases, intra-tumoral heterogeneity was found in 26.7% (n = 4). CONCLUSIONS: There is 20.3% KRAS discordance between primary and recurrent tumors, which is higher rate than is generally known. For selection of the effective target agent, KRAS analysis of recurred tumors will be necessary, if it is available.

New free radical-initiated peptide sequencing (FRIPS) mass spectrometry reagent with high conjugation efficiency enabling single-step peptide sequencing.

A newly designed TEMPO-FRIPS reagent, 4-(2,2,6,6-tetramethylpiperidine-1-oxyl) methyl benzyl succinic acid N-hydroxysuccinimide ester or p-TEMPO-Bn-Sc-NHS, was synthesized to achieve single-step free radical-initiated peptide sequencing mass spectrometry (FRIPS MS) for a number of model peptides, including phosphopeptides. The p-TEMPO-Bn-Sc-NHS reagent was conjugated to target peptides, and the resulting peptides were subjected to collisional activation. The peptide backbone dissociation behaviors of the MS/MS and MS3 experiments were monitored in positive ion mode. Fragment ions were observed even at the single-step thermal activation of the p-TEMPO-Bn-Sc-peptides, showing mainly a-/x- and c-/z-type fragments and neutral loss ions. This confirms that radical-driven peptide backbone dissociations occurred with the p-TEMPO-Bn-Sc-peptides. Compared to the previous version of the TEMPO reagent, i.e., o-TEMPO-Bz-C(O)-NHS, the newly designed p-TEMPO-Bn-Sc-NHS has better conjugation efficiency for the target peptides owing to its improved structural flexibility and solubility in the experimental reagents. An energetic interpretation using the survival fraction as a function of applied normalized collision energy (NCE) ascertained the difference in the thermal activation between p-TEMPO-Bn-Sc- and o-TEMPO-Bz-C(O)- radical initiators. This study clearly demonstrates that the application of the p-TEMPO-Bn-Sc- radical initiator can improve the duty cycle, and this FRIPS MS approach has the potential to be implemented in proteomics studies, including phosphoproteomics.

Colonic Chicken Skin Mucosa Surrounding Colon Polyps Is an Endoscopic Predictive Marker for Colonic Neoplastic Polyps.

Background/Aims: Narrow band imaging provides an accurate diagnosis of colonic polyps. However, these diagnostic modalities are not used as standard endoscopic tools in most institutions. This study aims to investigate whether the chicken skin mucosa (CSM) surrounding the colon polyp yields additional information about colorectal polyps, including histological differentiation of neoplastic and non-neoplastic polyps, under conventional white light colonoscopy. Methods: This study prospectively observed 173 patients who underwent endoscopic polypectomy and reviewed the clinical data and pathologic reports of 313 polyps from a university hospital. Two endoscopists each performed colonoscopy and polypectomy and assessed the CSM. The association between CSM surrounding colorectal polyps and histology was analyzed. Results: The majority (91.3%) of CSM-positive polyps were neoplastic (sensitivity, 37.90%; specificity, 86.15%; p<0.001). In logistic regression, the neoplastic polyps were associated with positive CSM (adjusted odds ratio [OR], 3.51; 95% confidence interval [CI], 1.45 to 9.25; p=0.007), protruded polyps (adjusted OR, 4.85; 95% CI, 1.65 to 17.23; p=0.008), and neoplastic histology-associated pit pattern (pit III, IV, and V) (adjusted OR, 10.14; 95% CI, 4.85 to 22.12; p=0.000). Furthermore, advanced adenomas were associated with positive CSM (adjusted OR, 5.64; 95% CI, 1.77 to 20.28; p=0.005), protruded polyps (adjusted OR, 3.30; 95% CI, 1.15 to 9.74; p= 0.026), and ≥10 cm polyp size (adjusted OR, 18.56; 95% CI, 3.89 to 147.01; p=0.001). Conclusions: Neoplastic and advanced polyps were associated with CSM-positive polyps. These findings suggest that CSM is a useful marker in differentiating neoplastic polyps and advanced polyps under conventional white colonoscopy.

Spontaneous regression of incidentally diagnosed bronchial squamous cell lung carcinoma after severe bronchitis: A case report.

Spontaneous regression of lung cancer is exceptionally rare. But there have been several intriguing cases reported in early and even advanced stages of lung cancer. Although the exact mechanism remains to be elucidated, the inflammation and immunologic response have been suggested as one of the means of spontaneous regression. Chronic inflammation is generally known to induce and aggravate tumorigenesis, but the relationship between cancer and inflammation highly depends on the contexts. Here, we present a case of a 60-year-old male ex-smoker who complained of recurrent hemoptysis, cough, and purulent sputum. The initial chest CT scan revealed diffuse bronchial thickening and an endobronchial mass-like lesion in the left lingular segment. The bronchoscopic and pathological findings also suggested a diagnosis of squamous cell carcinoma with severe mucosal inflammation. He was treated with antibiotics for the bronchitis during the first 1 week and his symptoms markedly improved. After 3 weeks, he underwent a follow-up examination. Chest computed tomography and bronchoscopy revealed the significant improvement of the bronchial narrowing and mucosal edema. Biopsy was performed several times around the lesion where the tissue was initially taken. However, the pathological results showed only chronic inflammation of bronchi, not cancer cells. Fortunately, there was no recurrence of lung cancer in follow-up chest computed tomography or bronchoscopy for almost 5 years. In this case, the incidentally diagnosed bronchial squamous cell carcinoma disappeared after severe inflammatory reaction of the bronchial wall. The clinician should remind the risk of early lung cancer accompanied with bronchitis in high-risk patients of lung cancer and also be aware that although it is very rare, the lesions could spontaneously regress.

Expression of HSP90 in gastrointestinal stromal tumours and mesenchymal tumours.

AIMS: Heat shock proteins (HSP) are up-regulated under conditions of increased stress, including cancer. Recently, HSP90 has been shown to be crucial to the expression and activation of the KIT oncoprotein. The aim was to explore the role of HSP90 expression as a prognostic marker and therapeutic target in gastrointestinal stromal tumours (GISTs) and other mesenchymal tumours. METHODS AND RESULTS: The expression of HSP90 was evaluated by immunohistochemistry in 92 GISTs, 47 mesenteric fibromatoses, six schwannomas, leiomyomas, melanomas, malignant peripheral nerve sheath tumours and leiomyosarcomas. Western blotting was performed in 22 selected cases. HSP90 overexpression was found in 33.7% of GISTs and was correlated with non-gastric location, mixed histological subtype, high mitotic index, high risk grades, and specific mutation genotypes. In mesenchymal tumours, HSP90 overexpression was found in 66.7% of malignant peripheral nerve sheath tumours, 83.3% of leiomyosarcomas, and 100% of melanomas. HSP90 expression by Western blotting correlated with the results of immunohistochemistry. The Cox proportional hazards model showed that HSP90 expression is an independent predictor of recurrence in GISTs (P = 0.003). CONCLUSIONS: Overexpression of HSP90 is predictive of adverse behaviour in GISTs and may provide a therapeutic solution to the challenge of imatinib-resistant GISTs and other mesenchymal sarcomas.

7-ketocholesterol induces endoplasmic reticulum stress in HT-29 cells.

7-Ketocholesterol (7-Kchol, oxidized cholesterol) is an important mediator of cell death in atherosclerosis mediated by up-regulated Nox 4 gene expression. In the current study using the human colon cancer HT-29 cell line, we have demonstrated that 7-Kchol promotes endoplasmic reticulum (ER) stress via gene up-regulation of ER chaperone and membrane kinases.

The expressions of autotaxin-lysophosphatidate signaling-related proteins in metastatic breast cancer.

PURPOSE: We evaluated the expression of autotaxin-lysophosphatidate signaling-related proteins and the clinical implications for metastatic breast cancer. METHODS: We constructed tissue microarrays (TMA) with 126 cases of metastatic breast cancer [31 (24.6%) bone metastases, 36 (28.6%) brain metastases, 11 (8.7%) liver metastases, and 48 (38.1%) lung metastasis], and we conducted immunohistochemical staining for the autotoxin-lysophosphatidate signaling-related proteins ATX, LPA1, LPA2, and LPA3. RESULTS: Stromal ATX (P = 0.006) and LPA1 (P < 0.001) were differently expressed according to their metastatic organ; stromal ATX showed high expression in bone metastasis, and LPA1 showed high expression in liver and lung metastases. Stromal ATX positivity was higher than others in luminal A type tumors (P = 0.035), and stromal LPA3 positivity was correlated with a high Ki-67 labeling index (LI) (P = 0.005). In univariate analysis, tumoral LPA3 negativity was correlated with shorter overall survival (OS) (P = 0.015) in metastatic breast cancer. When analyzed according to the metastatic sites, tumoral LPA3 negativity was correlated with shorter OS (P = 0.010) in lung metastasis, whereas stromal LPA3 negativity was correlated with shorter OS (P = 0.026) in brain metastasis. In multivariate Cox analysis, tumoral LPA3 negativity was an independent poor prognostic factor (HR = 2.311, 95% CI: 1.029-5.191, P = 0.043). CONCLUSION: Among autotoxin-lysophosphatidate signaling-related proteins, stromal ATX was highly expressed in bone metastases, and LPA1 was highly expressed in liver and lung metastases. Tumoral LPA3 might be a prognostic factor in metastatic breast cancer.

Proton Transfer Accounting for Anomalous Collision-Induced Dissociation of Proton-Bound Hoogsteen Base Pair of Cytosine and Guanine.

To understand the anomalous collision-induced dissociation (CID) behavior of the proton-bound Hoogsteen base pair of cytosine (C) and guanine (G), C:H+∙∙∙G, we investigated CID of a homologue series of proton-bound heterodimers of C, 1-methylcytosine, and 5-methylcytosine with G as a common base partner. The CID experiments were performed in an energy-resolved way (ER-CID) under both multiple and near-single collision conditions. The relative stabilities of the protonated complexes examined by ER-CID suggested that the proton-bound complexes produced by electrospray ionization in this study are proton-bound Hoogsteen base pairs. On the other hand, in contrast to the other base pairs, CID of C:H+∙∙∙G exhibited more abundant productions of C:H+, the fragment protonated on the moiety with a smaller proton affinity, than that of G:H+. This appeared to contradict general prediction based on the kinetic method. However, further theoretical exploration of potential energy surfaces found that there can be facile proton transfers in the proton-bound Hoogsteen base pairs during the CID process, which makes the process accessible to an additional product state of O-protonated C for C:H+ fragments. The presence of an additional dissociation channel, which in other words corresponds to twofold degeneracy in the transition state leading to C:H+ fragments, effectively doubles the apparent reaction rate for production of C:H+. In this way, the process gives rise to the anomaly, the observed pronounced formation of C:H+ in the CID of the proton-bound Hoogsteen base pair, C:H+∙∙∙G. Graphical Abstract ᅟ.

Voice Change Due to Paratracheal Air Cysts.

Paratracheal air cysts are a rare entity in which cystic formation occurs adjacent to the trachea. Most patients with paratracheal air cysts are asymptomatic, and the cysts are detected incidentally on chest radiograph or computed tomography (CT) scan. Most symptomatic patients complain of pulmonary symptoms or repeated respiratory infection. Rarely, the air cysts can lead to paralysis of the recurrent laryngeal nerve as a result of direct compression. We report a case of a 59-year-old male patient who presented with voice change, and the cause was identified as paratracheal air cysts on a chest CT scan. Surgical resection via video-assisted mediastinoscopy was performed, and the voice recovered immediately after the operation.

No Detection of Episomal or Integrated High-Risk Human Papillomavirus in Nonsmall Cell Lung Carcinomas among Korean Population.

OBJECTIVES: High-risk human papillomavirus (hrHPV) is known to be a representative cancer-causing agent in the genital and head and neck regions. Many studies have detected hrHPV DNA in nonsmall cell lung carcinoma. However, hrHPV-etiologic correlation in nonsmall cell lung carcinoma remains unclear. This study is designed to determine the prevalence of episomal or integrated hrHPV DNA in nonsmall cell lung carcinoma among the Korean population. METHODS: Surgically resected nonsmall cell lung carcinoma tissues, including 134 cases of squamous cell carcinoma (SqCC) and 99 cases of adenocarcinoma (ADC), were examined. In situ hybridization (ISH) for detecting episomal or integrated hrHPV DNA was performed using the INFORM HPV III Family 16 Probe (B) in the Ventana-validated assay. Anyplex II HPV28 detection kit based on real-time polymerase chain reaction was used for HPV DNA detection and genotyping. RESULTS: All members of the study population were of Korean ethnicity. Episomal or integrated hrHPV DNA ISH analysis result was negative in all 233 cases. One SqCC of 89 samples (42 SqCCs and 47 ADCs) was positive for an hrHPV genotype by Anyplex II HPV28 detection kit. CONCLUSION: Our finding did not demonstrate hrHPV-etiologic correlation in primary lung SqCC and ADC in the Korean population.

Up-regulation of Cytoplasmic CD24 Expression Is Associated with Malignant Transformation but Favorable Prognosis of Colorectal Adenocarcinoma.

AIM: Cluster of differentiation 24 (CD24) is known to be a putative marker of stem cell and tumor metastasis. This study aimed to verify the clinicopathological value of CD24 expression in colorectal adenocarcinoma (CRAC). MATERIALS AND METHODS: A total of seven whole-tissue sections of malignant polyps including the sequence non-neoplastic colorectal tissue-adenoma-CRAC, 48 adenomas and 161 CRACs arranged as tissue microarray were examined by immunohistochemistry for CD24 protein expression. Association of CD24 expression with clinicopathological parameters were also studied. RESULTS: CD24 was not detected in normal mucosal epithelia. Cytoplasmic CD24 expression was higher in CRAC than in adenoma (p<0.001). In CRACs, cytoplasmic CD24 expression was inversely correlated with poor differentiation (grades 1 to 3), tumor size, and pathological TNM stage (I to III versus IV) (p=0.005, p=0.034, and p=0.006, respectively). Statistical correlations between high CD24 expression and longer overall and disease-free survival were found (p=0.023 and p=0.033, respectively). CONCLUSION: Our findings suggest that up-regulation of CD24 expression in CRAC occurs at malignant transformation but is a marker of good prognosis, being down-regulated in pathological TNM stage IV. CD24 expression may be a challenging diagnostic marker in differentiating early invasive CRAC from adenoma and may serve as a prognostic marker in patients with CRAC.

MassARRAY, pyrosequencing, and PNA clamping for EGFR mutation detection in lung cancer tissue and cytological samples: a multicenter study.

BACKGROUND: Testing for epidermal growth factor receptor (EGFR) mutation is an important process in the therapeutic plan of patients with lung cancer. Recently, MassARRAY, based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, has been shown to be a useful method for somatic mutation analysis with pyrosequencing and peptide nucleic acid clamping (PNAc). METHODS: A total of 107 tissues and 67 cytological samples, which were confirmed to have lung adenocarcinoma at nine hospitals in Korea, were collected. Among the MassARRAY, pyrosequencing, and PNAc, the concordance rates and sensitivity of EGFR mutation detection were analyzed and validated in comparative tissue and cytological specimens. RESULTS: The concordance rate between pyrosequencing and PNAc was higher than that between MassARRAY and either of the pyrosequencing and PNAc in both tissue and cytological samples. In a comparison of diagnostic performance, MassARRAY (sensitivity: 85.7 %) was higher than pyrosequencing (74.3 %) and PNAc (70 %) in tissue, although pyrosequencing (80.5 %) was more highly sensitive, compared to MassARRAY (70.7 %) and PNAc (70.7 %) in terms of cytology. Unexpectedly, use of MassARRAY resulted in a significantly different EGFR mutation detection rate between tissue and cytological samples. CONCLUSIONS: When used for the detection of EGFR mutations, MassARRAY was more sensitive than pyrosequencing or PNA clamping in tissue, but not in cytological samples. In EGFR mutation detection between tissues and cytology, PNAc showed relatively higher concordance than MassARRAY or pyrosequencing.

Comparison of EGFR mutation detection between the tissue and cytology using direct sequencing, pyrosequencing and peptide nucleic acid clamping in lung adenocarcinoma: Korean multicentre study.

BACKGROUND: The importance of sensitive methods for the detection of epidermal growth factor receptor (EGFR) mutation is emphasized. The aim of this study is to perform comparative and concordance analyses of direct sequencing, pyrosequencing and peptide nucleic acid (PNA) clamping for detecting EGFR gene mutations using archived tissue and cytology specimens. METHODS: Samples from a total of 112 cases, which were diagnosed with adenocarcinoma of the lung at nine hospitals in Korea were collected. Using the above three methods, the concordance rates of EGFR mutations in exons 18, 19, 20 and 21 were analysed and validated in comparative tissue and cytology specimens. RESULTS: Comparison of EGFR mutation detection between the tissue and cytology had a high concordance rate. The diagnostic performance of pyrosequencing and PNA clamping in tissue was higher than that of direct sequencing as well as cytology. Additionally, among some of the patients who had EGFR wild type by single method, EGFR mutations were detected by other methods. Cytology specimens had a diagnostic performance for the detection of EGFR mutations. CONCLUSIONS: Cytology specimens had a diagnostic performance for the detection of EGFR mutations that was comparable to that of tissues. For detecting EGFR mutations, pyrosequencing or PNA clamping was more sensitive than direct sequencing. In EGFR mutation negative patients who are difficult to obtain tissue, repeating test using pyrosequencing or PNA clamping is recommended to improve the detection rate of EGFR mutation than only one, especially in cytology.

Pulmonary artery angiosarcoma confused with acute pulmonary thromboembolism: focusing on clinical and echocardiographic features in the differentiation of two categories.

Although pulmonary artery angiosarcoma is rare, it can be misdiagnosed as pulmonary embolism because of its similar clinical and diagnostic features. The diagnosis is often delayed and the misdiagnosis brings unnecessary treatment. Because we made a wrong diagnosis of pulmonary artery angiosarcoma as an acute pulmonary embolism, we did thrombolytic therapy which could be dangerous to the patient. In this case report, we focused on the clinical and echocardiographic features of pulmonary artery angiosarcoma which can be used in differentiating the diagnosis from pulmonary embolism.

Spontaneous regression of non-small cell lung cancer that progressed after multiple chemotherapies: A case report.

Spontaneous regression (SR) of cancer is defined as a complete or partial, temporary or permanent disappearance of all or at least some relevant parameters of malignant disease with inadequate or no treatment. SR of cancer is an extremely rare phenomenon. We report a case of a 67-year-old man who experienced SR of non-small-cell lung cancer (NSCLC), which progressed after fifth-line chemotherapy and regressed after chemotherapy ceased. Surprisingly, the primary tumor size continued to decrease for more than 13 months and his general condition markedly improved after discontinuation of the chemotherapy. To our knowledge, this is the first report of SR in a patient with NSCLC that was not responsive to a fifth round of chemotherapy.

Development of DNA chip for the simultaneous detection of various beta-lactam antibiotic-resistant genes.

A robust and fast DNA chip method was developed in order to detect the various beta-lactam antibiotic-resistance genes in one slide. These genes included PSE, OXA, FOX, MEN, CMY, TEM, SHV, OXY, and AmpC. beta-lactam antibiotic-resistance genes were labeled with a fluorescent nucleotide by a multiplex polymerase chain reaction using a mixture of specific primer sets for each gene. This labeled target was hybridized with a DNA chip that contained the spots of the specific probe DNAs for each beta-lactam antibiotic-resistance gene. This technique made it possible to detect the specific resistance gene, even in a single bacterium.