Background: Pseudomonas aeruginosa is one of the leading agents causing healthcare-associated infections (HAIs) due to its intrinsic resistance, its capacity to acquire resistance mechanisms, and its persistence in hospital environments. In Mexico, it ranks among the most frequently reported pathogens in national surveillance systems. The aim of this study was to characterize antimicrobial resistance profiles and the genetic determinants associated with MDR/XDR phenotypes in P. aeruginosa strains from HAIs at Hospital Juárez de México (HJM). Methods: Sixty-three strains from patients with HAIs were analyzed. Identification was confirmed by 16S rRNA gene sequencing. Antimicrobial susceptibility testing followed CLSI guidelines. MDR/XDR phenotypes were classified according to the Latin American consensus for categorizing MDR, XDR, and PDR pathogens. Screening for resistance mechanisms was carried out by PCR for the main β-lactamases circulating at HJM. Finally, mutations in the oprD gene were detected in imipenem-resistant isolates through amino acid sequence alignment. Results: Resistant phenotypes allowed the identification of MDR and XDR profiles. Only the metallo-β-lactamase bla_VIM was detected. Analysis of oprD porin sequences revealed recurrent mutations (S103T, T115K, L170F, G186P, and T189V) associated with imipenem resistance. Conclusions: In P. aeruginosa, the presence of bla_VIM and structural alterations in OprD confirms the multifactorial nature of carbapenem resistance. These findings underscore the need to strengthen microbiological surveillance programs and antimicrobial stewardship strategies to mitigate the impact and spread of MDR/XDR isolates.

In Mexico, syphilis and tuberculosis are infectious diseases subject to mandatory and immediate epidemiological surveillance, both with special systems that allow nominal follow-up for either variant. Surveillance uses the operational definitions of probable and confirmed cases established in the manual for epidemiological surveillance issued by the General Directorate of Epidemiology of the Ministry of Health. However, both diseases, mainly in the chronic state, present challenges because of their ability to mimic autoimmune disorders. This review explores the phenomenon of clinical and immunological mimicry in secondary and tertiary syphilis, as well as in extrapulmonary tuberculosis, and analyzes its implications for the accuracy of case reporting at the national level. Evidence shows that both infections can present systemic inflammatory features, such as elevated acute phase reactants, positive autoantibodies, and alterations in cerebrospinal fluid that resemble autoimmune profiles. These overlaps can lead to misdiagnosis, inappropriate immunosuppressive treatment and misclassification of confirmed cases within the Mexican surveillance system. Surveillance of these conditions is robust; however, current operational definitions have weaknesses, particularly when atypical or autoimmune conditions are present, as they only focus on cases with the highest prevalence or public health impact. This manuscript proposes the integration of differential diagnostic algorithms and expanded laboratory criteria, including autoimmune markers and molecular tests, into surveillance protocols. Although individual efforts exist in health institutions, in our country, the absence of autoimmune diseases in the national register of obligatory notification stands out, contrasting with surveillance models in other countries, where autoimmune diseases are tracked systematically. To improve diagnostic accuracy and reporting, surveillance systems should incorporate a syndromic and etiological approach, recognizing infectious autoimmune mimicry as a factor in the final recording of confirmed cases to avoid epidemiological silence.

Microbiological verification of reprocessed mechanical ventilators serves as a quality control measure aimed at interrupting potential transmission routes of pathogens before patient intubation. The aim of this study was to describe the microbiological findings and operational costs of the post-reprocessing surveillance program for mechanical ventilators at Hospital Juárez de México and to contextualize these costs using a hypothetical VAP-associated economic reference. This retrospective observational study included 1456 post-reprocessing microbiological evaluation events involving mechanical ventilators previously used by patients with laboratory-confirmed ventilator-associated pneumonia (VAP). All events meeting the surveillance eligibility criteria during the study period were included. Inspiratory and expiratory limbs were sampled for bacterial culture, with microbial identification by mass spectrometry. Any bacterial growth was considered residual contamination, and the ventilator underwent a new complete cycle of cleaning and high-level disinfection. An institutional analysis was applied to estimate operational costs and to contextualize the potential VAP-associated economic burden using the culture-positive ventilators as a hypothetical reference calculation, without assuming that each positive device represented a prevented VAP episode. Residual bacterial contamination was detected in 95 evaluation events (6.5%), with recovery of organisms including Acinetobacter baumannii and Pseudomonas aeruginosa. The operational cost of the microbiological surveillance program was 40,993 USD. Using institutional VAP cost estimates, a hypothetical calculation assigning the annual VAP cost to each of the 95 culture-positive evaluation events produced a reference value of 1,285,650 USD. Under this reference calculation, the difference between the VAP-associated reference value and program cost was 1,244,657 USD, corresponding to a cost ratio of 31.4:1. These estimates are hypothetical and depend on assumptions regarding infection probability and preventive effectiveness; they do not represent demonstrated economic savings. The break-even probability of device-attributable VAP per culture-positive evaluation event was 3.19%, assuming full institutional coverage of VAP-associated costs and complete prevention of these episodes through additional reprocessing. Within this defined surveillance population, microbiological surveillance of reprocessed mechanical ventilators is a useful quality-control strategy prior to patient intubation.

Hospital wastewater (HWW) is increasingly recognized as an environmental hotspot for the selection and dissemination of antimicrobial resistance (AMR). Although surveillance programs primarily target ESKAPE pathogens, the contribution of environmental bacteria such as Aeromonas spp. remains poorly characterized. The aim of this work was to investigate antimicrobial resistance mechanisms, focusing on carbapenem and cephalosporin resistance, in Aeromonas spp. recovered from HWW. Thirty Aeromonas isolates were identified by rpoD restriction fragment length polymorphism analysis and characterized by antimicrobial susceptibility testing, detection of β-lactam resistance genes, class 1 integrons, and genetic relatedness using ERIC-PCR fingerprinting. All isolates exhibited operationally defined multidrug-resistant (MDR) or extensively drug-resistant (XDR) phenotypes, with resistance predominating against cephalosporins, carbapenems, and trimethoprim–sulfamethoxazole. The clinically relevant gene families/groups bla_KPC family, bla_OXA-48-like, bla_CTX-M group 1, and bla_SHV were detected by PCR, whereas bla_NDM, bla_VIM, bla_IMP, and mcr-1 were absent. Class 1 integrons were identified in 36.7% of isolates, revealing diverse cassette arrays carrying dfrA and aadA resistance genes. ERIC-PCR demonstrated high fingerprint diversity with limited genetic relatedness. Microbiological surveillance of HWW revealed that Aeromonas populations constitute an environmental reservoir of clinically relevant β-lactam resistance determinants, supporting further evaluation of their potential role in AMR surveillance strategies at the hospital–environment interface.