Resistencia antibiótica y aspectos clínicos de Neisseria gonorrhoeae anorrectal en un hospital de CABA, Argentina / Antimicrobial resistance and clinical aspects in anorectal Neisseria gonorrhoeae in a hospital in CABA, Argentina

La infección por Neisseria gonorrhoeae (NG) es considerada de alta prioridad en salud pública, por su capacidad para desarrollar resistencia a la mayoría de los antibióticos empleados para tratarla. La presentación anorrectal suele ser asintomática y frecuente en hombres que tienen sexo con hombres (HSH). En Argentina, se recomienda terapia antibiótica dual (ceftriaxona+azitromicina/doxiciclina) como primera línea empírica. Este estudio observacional y retrospectivo se realizó para evaluar el porcentaje de positividad de NG anorrectal, el perfil de sensibilidad a penicilina, tetraciclina, ciprofloxacina, ceftriaxona, cefixima y azitromicina, así como los aspectos clínicos-epidemiológicos de los pacientes atendidos entre 20/10/2015 y 20/03/2020 en consultorios coloproctológicos de un hospital público. Se detectaron 55/436 hisopados rectales positivos para NG (13%). El 95% era HSH y 71%, VIH+. En 18/55 NG fue la única infección. Las co-infecciones más frecuentes: HPV (38%) y C. trachomatis (35%). La sensibilidad a cefalosporinas de espectro extendido (CEE) y a azitromicina fueron 100% y 98%, respectivamente. Se observó la emergencia local de los primeros cinco aislamientos de NG anorrectal con sensibilidad reducida (SR) a CEE, el primer aislamiento con categoría no-sensible a azitromicina y otro con SR a azitromicina concomitantemente con SR a CEE. Aunque el uso de terapia empírica dual sigue siendo adecuado para nuestra institución, se observó la emergencia de aislamientos con SR y NS a las drogas de primera línea, evidenciando la importancia de la vigilancia epidemiológica a nivel local para definir los tratamientos empíricos.

Neisseria gonorrhoeae (NG) infection is considered a high public health priority because of its ability to develop resistance to most of the antibiotics used to treat it.The anorectal presentation is generally asymptomatic and frequent in men who have sex with men (MSM). In Argentina, dual therapy (ceftriaxone+azithromycin/doxycycline) is recommended as first line empiric therapy.This observational and retrospective study was conducted to evaluate the percentage of anorectal NG positivity, the susceptibility profile to penicillin, tetracycline, ciprofloxacin, ceftriaxone, cefixime and azithromycin, as well as the clinical-epidemiological aspects of patients attended between 20/10/2015 and 20/03/2020 in coloproctology of a public hospital.We detected 55/436 positive rectal swabs for NG (13%). 95% were MSM and 71% were PLHIV. In 18/55 NG was the only infection. The most frequent co-infections: HPV (38%) and C. trachomatis (35%).Susceptibility to extended-spectrum cephalosporins (ESCs) and azithromycin was 100% and 98%, respectively. Local emergence of the first five anorectal NG isolates with decreased susceptibility (DS) to ESCs, the first isolate with nonsusceptible category to azithromycin and another with DS to azithromycin concomitantly with DS to ESCs were observed.Although the use of dual empirical therapy continues to be adequate for our institution, the emergence of isolates with DS and NS to first-line drugs was observed, evidencing the importance of epidemiological surveillance at the local level to define empirical treatments

KPC-2 allelic variants in Klebsiella pneumoniae isolates resistant to ceftazidime-avibactam from Argentina: blaKPC-80, blaKPC-81, blaKPC-96 and blaKPC-97.

Ceftazidime-avibactam (CZA) therapy has significantly improved survival rates for patients infected by carbapenem-resistant bacteria, including KPC producers. However, resistance to CZA is a growing concern, attributed to multiple mechanisms. In this study, we characterized four clinical CZA-resistant Klebsiella pneumoniae isolates obtained between July 2019 and December 2020. These isolates expressed novel allelic variants of blaKPC-2 resulting from changes in hotspots of the mature protein, particularly in loops surrounding the active site of KPC. Notably, KPC-80 had an K269_D270insPNK mutation near the Lys270-loop, KPC-81 had a del_I173 mutation within the Ω-loop, KPC-96 showed a Y241N substitution within the Val240-loop and KPC-97 had an V277_I278insNSEAV mutation within the Lys270-loop. Three of the four isolates exhibited low-level resistance to imipenem (4 µg/mL), while all remained susceptible to meropenem. Avibactam and relebactam effectively restored carbapenem susceptibility in resistant isolates. Cloning mutant blaKPC genes into pMBLe increased imipenem MICs in recipient Escherichia coli TOP10 for blaKPC-80, blaKPC-96, and blaKPC-97 by two dilutions; again, these MICs were restored by avibactam and relebactam. Frameshift mutations disrupted ompK35 in three isolates. Additional resistance genes, including blaTEM-1, blaOXA-18 and blaOXA-1, were also identified. Interestingly, three isolates belonged to clonal complex 11 (ST258 and ST11) and one to ST629. This study highlights the emergence of CZA resistance including unique allelic variants of blaKPC-2 and impermeability. Comprehensive epidemiological surveillance and in-depth molecular studies are imperative for understanding and monitoring these complex resistance mechanisms, crucial for effective antimicrobial treatment strategies. IMPORTANCE: The emergence of ceftazidime-avibactam (CZA) resistance poses a significant threat to the efficacy of this life-saving therapy against carbapenem-resistant bacteria, particularly Klebsiella pneumoniae-producing KPC enzymes. This study investigates four clinical isolates exhibiting resistance to CZA, revealing novel allelic variants of the key resistance gene, blaKPC-2. The mutations identified in hotspots surrounding the active site of KPC, such as K269_D270insPNK, del_I173, Y241N and V277_I278insNSEAV, prove the adaptability of these pathogens. Intriguingly, low-level resistance to imipenem and disruptions in porin genes were observed, emphasizing the complexity of the resistance mechanisms. Interestingly, three of four isolates belonged to clonal complex 11. This research not only sheds light on the clinical significance of CZA resistance but also shows the urgency for comprehensive surveillance and molecular studies to inform effective antimicrobial treatment strategies in the face of evolving bacterial resistance.

Co-integrate Col3m bla NDM-1-harboring plasmids in clinical Providencia rettgeri isolates from Argentina.

The first cases of bla NDM in Argentina were detected in three Providencia rettgeri (Pre) recovered from two hospitals in Buenos Aires city in 2013. The isolates were genetically related, but the plasmid profile was different. Here, we characterized the bla NDM-1-harboring plasmids of the first three cases detected in Argentina. Hybrid assembly obtained from short- and long-read sequencing rendered bla NDM-1 in Col3M plasmids of ca. 320 kb (p15268A_320) in isolate PreM15268, 210 kb (p15758B_210) in PreM15758, and 225 kb (p15973A_225) in PreM15973. In addition, PreM15758 harbored a 98-kb circular plasmid (p15758C_98) flanked by a putative recombination site (hin-TnAs2), with 100% nucleotide ID and coverage with p15628A_320. Analysis of PFGE/S1-nuclease gel, Southern hybridization with bla NDM-1 probe, hybrid assembly of short and long reads suggests that pM15758C_98 can integrate by homologous recombination. The three bla NDM-1-plasmids were non-conjugative in vitro. Moreover, tra genes were incomplete, and oriT was not found in the three bla NDM-1-plasmids. In two isolates, blaNDM-1 was embedded in a partially conserved structure flanked by two ISKox2. In addition, all plasmids harbored aph(3')-Ia, aph(3')-VI, and qnrD1 genes and aac(6´)Ib-cr, bla OXA-1, catB3, and arr3 as part of a class 1 integron. Also, p15268A_320 and p15973A_225 harbored bla PER-2. To the best of our knowledge, this is the first report of clinical P. rettgeri harboring blaNDM-1 in an atypical genetic environment and located in unusual chimeric Col3M plasmids. The study and continuous surveillance of these pathogens are crucial to tracking the evolution of these resistant plasmids and finding solutions to tackle their dissemination. IMPORTANCE Infections caused by carbapenem hydrolyzing enzymes like NDM (New Delhi metallo-beta-lactamase) represent a serious problem worldwide because they restrict available treatment options and increase morbidity and mortality, and treatment failure prolongs hospital stays. The first three cases of NDM in Argentina were caused by genetically related P. rettgeri recovered in two hospitals. In this work, we studied the genetic structure of the plasmids encoding bla NDM in those index cases and revealed the enormous plasticity of these genetic elements. In particular, we found a small plasmid that was also found inserted in the larger plasmids by homologous recombination as a co-integrate element. We also found that the bla NDM plasmids were not able to transfer or move to other hosts, suggesting their role as reservoir elements for the acquisition of resistance genes. It is necessary to unravel the dissemination strategies and the evolution of these resistant plasmids to find solutions to tackle their spread.

Utilidad del panel FilmArray® BCID en la detección de bacteriemia: estudio multicéntrico latinoamericano / Usefulness of the FilmArray® BCID panel in the detection of bacteremia: Latin American multicenter study

Resumen Los objetivos de este estudio fueron determinar el desempeño del panel BCID de FilmArray® y establecer el impacto de estos resultados en el tratamiento antimicrobiano de pacientes con bacteriemia en 11 hospitales de Latinoamérica. Se incluyeron 397 episodios de bacteriemia y se documentaron 551 microorganismos aislados de hemocultivos. La identificación microbiana fue correcta en el 91,4% (504/551) de los aislados y en el 98,6% (504/511) si se consideran solo los microorganismos incluidos en el panel BCID. La sensibilidad en la detección de los genes mecA, vanA/B y blaKPC fue del 100% y la especificidad fue del 97%, 100% y 99,6% respectivamente. La notificación temprana del resultado permitió cambios terapéuticos en 242 episodios (60,9%). El panel BCID es un método confiable y rápido para la detección de mecanismos críticos de resistencia y de los microorganismos más frecuentemente aislados de bacteriemias y permite la optimización temprana del tratamiento antimicrobiano.

Abstract The objectives of this study were to determine the performance of the BCID panel and to establish the impact of these results on the antimicrobial treatment of patients with bacteremia in 11 hospitals in Latin America. Three hundred and ninety-seven episodes of bacteremia were included and 551 microorganisms isolated from blood cultures were documented. Microbial identification was correct in 91.4% (504/551) of the isolates and in 98.6% (504/511) if only the microorganisms included in the BCID panel are considered. The sensitivity in the detection of the genes mecA, vanA/B and blaKPC was 100% and the specificity was 97%, 100% and 99.6% respectively. Early notification of the outcome allowed therapeutic changes in 242 episodes (60.9%). The BCID panel is a reliable and rapid method for the detection of critical resistance mechanisms and of the microorganisms most frequently isolated from bacteremia and it enables early optimisation of antimicrobial treatment.

Resumo Os objetivos deste estudo foram determinar o desempenho do painel BCID do FilmArray® e estabelecer o impacto desses resultados no tratamento antimicrobiano de pacientes com bacteremia em 11 hospitais da América Latina. Trezentos e noventa e sete episódios de bacteremia foram incluídos e 551 microrganismos isolados de hemoculturas foram documentados. A identificação microbiana foi correta em 91,4% (504/551) dos isolados e em 98,6% (504/511) considerando apenas os microrganismos incluídos no painel BCID. A sensibilidade na detecção dos genes mecA, vanA/B e blaKPC foi de 100% e a especificidade foi de 97%, 100% e 99,6% respectivamente. A notificação precoce do desfecho permitiu mudanças terapêuticas em 242 episódios (60,9%). O painel BCID é um método confiável e rápido para a detecção de mecanismos críticos de resistência e dos microrganismos mais frequentemente isolados da bacteremia e permite a otimização precoce do tratamento antimicrobiano.

Characterization of the First mecA-Positive Multidrug-Resistant Staphylococcus pseudintermedius Isolated from an Argentinian Patient.

Staphylococcus pseudintermedius is commonly associated with colonization or infection in dogs, and was identified as a novel species within the genus Staphylococcus in 2006. Methicillin resistance emerged in S. pseudintermedius during the last decade. We describe here a genomic characterization of the first methicillin-resistant S. pseudintermedius (MRSP) recovered from a human patient in Argentina. The strain was phenotypically identified as MRSP 8510 by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and antimicrobial susceptibility testing. We assessed genetic characterization by mecA PCR, SCCmec (staphylococcal chromosomal cassette) typing, and whole-genome sequencing. MRSP 8510 was phenotypically resistant to six classes of antimicrobial agents, consistent with the genes found in its genome. We concluded that MRSP 8510 was a multidrug-resistant ST1412 isolate. This study highlights the importance of the detection and characterization of pathogens with potential risks of zoonotic transmission to humans, as they may constitute a reservoir of genes associated with antimicrobial resistance.

Characterization of Tn6238 with a new allele of aac(6')-Ib-cr.

Here, we report that the genetic structure of Tn1331 remained conserved in Argentina from 1989 to 2013 (72 of 73 isolates), with the exception being the plasmid-borne Tn1331-like transposon Tn6238 containing a new aac(6')-Ib-cr allele recovered from a colistin-resistant Klebsiella pneumoniae clinical isolate. A bioinformatic analysis of aac(6')-Ib-like gene cassettes suggests that this new aac(6')-Ib-cr allele emerged through mutation or homologous recombination in the Tn1331 genetic platform. Tn6238 is a novel platform for the dissemination of aminoglycoside and fluoroquinolone resistance determinants.

[First isolation in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin]. / Primer aislamiento en Argentina de Staphylococcus aureus resistente a la meticilina adquirido en la comunidad con sensibilidad intermedia a la vancomicina y no sensibilidad a la daptomicina.

UNLABELLED: We report the first case in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin. CASE REPORT: A male patient with a history of chronic renal failure on hemodialysis and hip fracture osteosynthesis was admitted to hospital for persistent febrile syndrome following the displacement of the prosthesis by trauma. Blood cultures grew community-acquired methicillin-resistant Staphylococcus aureus. During treatment with vancomycin and daptomycin, a gradual increase in vancomycin MIC of 1 µg/ml (VSSA) to 2 µg/ml (h-VISA) and 4 µg/ml (VISA) was observed, as well as the emergence of non-susceptibility to daptomycin (MIC = 4 µg/ml). By suspending vancomycin and daptomycin, the strain reversed to the susceptible phenotype to both drugs. It is mandatory to evaluate by MIC the susceptibility to vancomycin and daptomycin during treatment when these drugs are used as therapy.

Primer aislamiento en Argentina de Staphylococcus aureus resistente a la meticilina adquirido en la comunidad con sensibilidad intermedia a la vancomicina y no sensibilidad a la daptomicina / [First isolation in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin].

UNLABELLED: We report the first case in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin. CASE REPORT: A male patient with a history of chronic renal failure on hemodialysis and hip fracture osteosynthesis was admitted to hospital for persistent febrile syndrome following the displacement of the prosthesis by trauma. Blood cultures grew community-acquired methicillin-resistant Staphylococcus aureus. During treatment with vancomycin and daptomycin, a gradual increase in vancomycin MIC of 1 Ag/ml (VSSA) to 2 Ag/ml (h-VISA) and 4 Ag/ml (VISA) was observed, as well as the emergence of non-susceptibility to daptomycin (MIC = 4 Ag/ml). By suspending vancomycin and daptomycin, the strain reversed to the susceptible phenotype to both drugs. It is mandatory to evaluate by MIC the susceptibility to vancomycin and daptomycin during treatment when these drugs are used as therapy.

Primer aislamiento en Argentina de Staphylococcus aureus resistente a la meticilina adquirido en la comunidad con sensibilidad intermedia a la vancomicina y no sensibilidad a la daptomicina. / [First isolation in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin].

UNLABELLED: We report the first case in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin. CASE REPORT: A male patient with a history of chronic renal failure on hemodialysis and hip fracture osteosynthesis was admitted to hospital for persistent febrile syndrome following the displacement of the prosthesis by trauma. Blood cultures grew community-acquired methicillin-resistant Staphylococcus aureus. During treatment with vancomycin and daptomycin, a gradual increase in vancomycin MIC of 1 Ag/ml (VSSA) to 2 Ag/ml (h-VISA) and 4 Ag/ml (VISA) was observed, as well as the emergence of non-susceptibility to daptomycin (MIC = 4 Ag/ml). By suspending vancomycin and daptomycin, the strain reversed to the susceptible phenotype to both drugs. It is mandatory to evaluate by MIC the susceptibility to vancomycin and daptomycin during treatment when these drugs are used as therapy.

[CHROMagar KPC. Comparison with the method proposed by the Centers for Disease Control and Prevention (CDC, USA) for rectal screening and evaluation of false positive results]. / CHROMagar Kpc. Comparación con el método propuesto por los Centros para el Control y Prevención de Enfermedades (CDC, EE.UU.) para el estudio de portación rectal y evaluación de falsos positivos.

Eighty one rectal swabs (RS) were cultured on CHROMagar KPC and the CDC method. Of the 81 samples, 9 were positive for KPC-producing Klebsiella pneumoniae on CHROMagar KPC, and 6 for the CDC method. CHROMagar KPC had two false positive (FP) results: 1 K. pneumoniae and 1 Acinetobacter sp. FP results on the CDC method were: 25 Acinetobacter spp., 2 Escherichia coli and 4 K. pneumoniae: CHROMagar KPC yielded a better recovery of KPC-producing bacteria and less FP results than CDC method. In order to evaluate FP results on CHROMagar KPC, 1247 RS were cultured and yielded 1021 negatives, 171 KPC-producing K. pneumoniae and 55 FP (4.4 %). Because of the FP results growing on CHROMagar KPC, KPC must be phenotypically confirmed in the bacteria isolated.

Transposons and integrons in colistin-resistant clones of Klebsiella pneumoniae and Acinetobacter baumannii with epidemic or sporadic behaviour.

Multiple transposons, integrons and carbapenemases were found in Klebsiella pneumoniae colistin-resistant isolates as well as a genomic resistance island of the AbaR type in Acinetobacter baumannii colistin-resistant isolates from different hospitals from Buenos Aires City. PFGE analysis showed a polyclonal dissemination of antimicrobial resistance mechanisms among K. pneumoniae isolates, while in A. baumannii isolates the epidemic clone 1 from South America was found. Resistance determinants associated with horizontal gene transfer are contributing to the evolution to pandrug resistance in both epidemic and sporadic clones.

CHROMagar KPC. Comparación con el método propuesto por los Centros para el Control y Prevención de Enfermedades (CDC, EE.UU.) para el estudio de portación rectal y evaluación de falsos positivos / CHROMagar KPC. Comparison with the method proposed by the Centers for Disease Control and Prevention (CDC, USA) for rectal screening and evaluation of false positive results

Se cultivaron 81 hisopados rectales en el medio CHROMagar KPC y por el método del CDC. Fueron positivos para Klebsiella pneumoniae KPC en CHROMagar KPC, 9/81 y 6/81 con el método del CDC. El medio CHROMagar KPC tuvo dos falsos positivos: 1 K. pneumoniae y 1 Acinetobacter sp. Los falsos positivos del método CDC fueron: 25 Acinetobacter spp., 2 Escherichia coli y4K. pneumoniae. El empleo del medio CHROMagar KPC resultó ser un método con mayor recuperación de aislamientos productores de KPC y menos falsos positivos que el método del CDC. Para evaluar los falsos positivos en el medio CHROMagar KPC se cultivaron 1247 hisopados rectales. Se obtuvieron 1021 negativos, 171 K. pneumoniae KPC y 55 (4,4 %) falsos positivos. Debido al desarrollo de falsos positivos en el medio CHROMagar KPC, se debe confirmar por caracterización fenotípica la presencia de KPC en las bacterias aisladas.(AU)

Eighty one rectal swabs (RS) were cultured on CHROMagar KPC and the CDC method. Of the 81 samples, 9 were positive for KPC-producing Klebsiella pneumoniae on CHROMagar KPC, and 6 for the CDC method. CHROMagar KPC had two false positive (FP) results: 1 K. pneumoniae and 1 Acinetobacter sp. FP results on the CDC method were: 25 Acinetobacter spp., 2 Escherichia coli and 4 K. pneumoniae. CHROMagar KPC yielded a better recovery of KPC-producing bacteria and less FP results than CDC method. In order to evaluate FP results on CHROMagar KPC, 1247 RS were cultured and yielded 1021 negatives, 171 KPC-producing K. pneumoniae and 55 FP (4.4 %). Because of the FP results growing on CHROMagar KPC, KPC must be phenotypically confirmed in the bacteria isolated.(AU)

CHROMagar KPC. Comparación con el método propuesto por los Centros para el Control y Prevención de Enfermedades (CDC, EE.UU.) para el estudio de portación rectal y evaluación de falsos positivos / CHROMagar KPC. Comparison with the method proposed by the Centers for Disease Control and Prevention (CDC, USA) for rectal screening and evaluation of false positive results

Se cultivaron 81 hisopados rectales en el medio CHROMagar KPC y por el método del CDC. Fueron positivos para Klebsiella pneumoniae KPC en CHROMagar KPC, 9/81 y 6/81 con el método del CDC. El medio CHROMagar KPC tuvo dos falsos positivos: 1 K. pneumoniae y 1 Acinetobacter sp. Los falsos positivos del método CDC fueron: 25 Acinetobacter spp., 2 Escherichia coli y4K. pneumoniae. El empleo del medio CHROMagar KPC resultó ser un método con mayor recuperación de aislamientos productores de KPC y menos falsos positivos que el método del CDC. Para evaluar los falsos positivos en el medio CHROMagar KPC se cultivaron 1247 hisopados rectales. Se obtuvieron 1021 negativos, 171 K. pneumoniae KPC y 55 (4,4 %) falsos positivos. Debido al desarrollo de falsos positivos en el medio CHROMagar KPC, se debe confirmar por caracterización fenotípica la presencia de KPC en las bacterias aisladas.

Eighty one rectal swabs (RS) were cultured on CHROMagar KPC and the CDC method. Of the 81 samples, 9 were positive for KPC-producing Klebsiella pneumoniae on CHROMagar KPC, and 6 for the CDC method. CHROMagar KPC had two false positive (FP) results: 1 K. pneumoniae and 1 Acinetobacter sp. FP results on the CDC method were: 25 Acinetobacter spp., 2 Escherichia coli and 4 K. pneumoniae. CHROMagar KPC yielded a better recovery of KPC-producing bacteria and less FP results than CDC method. In order to evaluate FP results on CHROMagar KPC, 1247 RS were cultured and yielded 1021 negatives, 171 KPC-producing K. pneumoniae and 55 FP (4.4 %). Because of the FP results growing on CHROMagar KPC, KPC must be phenotypically confirmed in the bacteria isolated.