(1) Background: Resistant Pseudomonas aeruginosa (PA) infections have limited treatment options. Data on the activity of ceftolozane-tazobactam (C-T) against PA in Thailand are limited. Objectives: The objective of this study was to identify the in vitro activity of C-T against general and resistant PA isolates from patients with real clinical infections from the HRH Princess Maha Chakri Sirindhorn Medical Center (MSMC) compared to other antibiotics and to study the resistant molecular patterns of those PA strains which were resistant to C-T. (2) Materials and Methods: This was an in vitro susceptibility study of 100 PA isolates plus an additional seven resistant PA isolates collected from MSMC patients. All PA isolates were tested with susceptibility broth (Sensititre™) and C-T minimal inhibitory concentration (MIC) test strips (Liofilchem, Roseto degli, Abruzzi, Italy). The C-T-resistant PA isolates were analyzed for six β-lactamase genes (bla_CTX-M, bla_NDM, bla_IMP, bla_VIM, bla_OXA-23 and bla_OXA-48) and the mcr-1 gene. (3) Results: A total of 100 PA isolates were collected between January 2020 and January 2021 and between February 2021 and September 2021 for the additional 7 resistant isolates. There were 18 resistant PA isolates (6 MDR, 11 XDR and 1 pan-drug resistant isolate). The overall susceptibility of the initial 100 PA isolates and the 18 resistant PA isolates was 94% and 44.5%, respectively, for C-T. The C-T susceptibility rates for isolates non-susceptible to ceftazidime, piperacillin-tazobactam, carbapenems and antipseudomonal β-lactams were 65.5%, 69.7%, 50% and 44.5%, respectively. Among the 10 isolates which were resistant to C-T, there were only 3 isolates found to have the resistant gene, which included 1 for bla_IMP, 1 for bla_VIM and 1 for bla_NDM. (4) Conclusions: Although C-T was the best susceptibility antibiotic overall for PA isolates and MDR PA isolates at the MSMC, most of the XDR PA isolates and the PDR PA isolate were not susceptible to C-T. The mechanisms for C-T resistance involved multiple factors including the presence of bla_IMP, bla_VIM and bla_NDM.

Background: Tuberculosis (TB) remains a primary global health concern, despite the widespread availability of effective chemotherapeutic interventions. The emergence and dissemination of drug-resistant strains of Mycobacterium tuberculosis, particularly those exhibiting resistance to rifampicin, present significant obstacles to the success of TB control programs. Consequently, there is an urgent need for rapid, sensitive, and specific molecular diagnostic tools to inform timely clinical decision-making and reduce the transmission of disease. Loop-mediated isothermal amplification (LAMP) has gained attention as a promising alternative to conventional polymerase chain reaction (PCR) techniques. This method, which facilitates DNA amplification under constant temperature conditions, offers advantages including high specificity, rapid turnaround time, and operational simplicity—features that render it especially suitable for implementation in resource-limited settings. Methods: In this study, a LAMP assay targeting the rpoB gene was developed, with particular focus on detecting the codon 531 C→T mutation associated with rifampicin resistance. A set of four to six primers was designed to recognize six distinct regions of the target sequence. Allele-specific amplification was achieved by incorporating a deliberate single nucleotide mismatch at the 3′ terminus of the B2 primer to enable precise discrimination between wild-type and mutant alleles. The assay was conducted at an optimized temperature of 61 °C for 60 min, followed by visual detection using a lateral flow dipstick (LFD) within five minutes. Results: The LAMP-LFD assay demonstrated 100% concordance with drug susceptibility testing (DST) and DNA sequencing. No cross-reactivity with wild-type strains was observed, underscoring the assay’s high specificity. Conclusions: This platform offers a robust, field-deployable solution for detecting the codon 531 C→T mutation associated with rifampicin resistance in low-resource settings.

Background/Objectives: Rapid identification of Staphylococcus aureus and differentiation of methicillin-resistant S. aureus (MRSA) remains critical to infection control and antimicrobial stewardship, particularly where rapid screening is desirable. In this study, we developed and evaluated a duplex recombinase polymerase amplification coupled with lateral flow dipstick (RPA–LFD) platform enabling simultaneous detection of the species-associated spa locus and the methicillin resistance determinant mecA within a single isothermal reaction. Methods: Primer–probe architecture and reaction parameters were systematically adjusted, with 39 °C selected as the operating temperature, to enable concurrent visual detection of both targets within 15 min. Results: In a preliminary ten-fold serial dilution experiment, visible detection was observed down to 10¹ CFU/mL for both targets, whereas conventional PCR produced visible amplification down to 10² CFU/mL under the respective assay conditions. This difference represents an assay-specific observation and was not used to establish a statistically validated detection limit. No cross-reactivity was observed against a panel of non-target bacterial species. A preliminary evaluation of 25 nasal swab-derived DNA specimens showed complete concordance with reference PCR within this limited sample set. Conclusions: These findings demonstrate the feasibility of concurrent visual detection of species-associated and resistance targets within a single RPA–LFD configuration. Although further analytical and clinical validation is required, the platform provides a technical framework for simplified duplex isothermal detection of S. aureus and mecA.