Resumen Los patógenos bacterianos pueden detectarse en las infecciones respiratorias virales y son una causa importante de morbimortalidad. La prevalencia de Chlamydia pneumoniae en pacientes infectados con SARS-CoV-2 ha sido poco estudiada. El objetivo de la presente revisión fue describir la prevalencia de C. pneumoniae en pacientes con enfermedad por coronavirus 2019 (COVID-19). Para ello se realizó una búsqueda bibliográfica en Medline y Google Académico, entre enero de 2020 y agosto de 2021. De la revisión surgieron 11 artículos (cinco estudios de casos transversales y seis estudios retrospectivos), que incluyeron un total de 18.450 pacientes. La detección de C. pneumoniae varió entre el 1,78 y 71,4% del total de las coinfecciones. La media de edad de los pacientes osciló entre los 35 y 71 años y el 65% fueron hombres. En la mayoría de los estudios se informaron comorbilidades preexistentes y la mayor parte de los pacientes presentó fiebre, tos y disnea. Además, se describió linfopenia y eosinofilopenia en pacientes con COVID-19 coinfectados. La principal manifestación en la tomografía computarizada fue densidad de vidrio esmerilado, consolidación y neumonía bilateral. La mayoría de los pacientes recibió antibióticos de manera empírica. La coinfección bacteriana no se asoció con un aumento de ingresos en cuidados intensivos ni mortalidad. A pesar de la prescripción de antimicrobianos empíricos en pacientes con infecciones respiratorias asociadas a coronavirus existen pocos reportes de detección de coinfección bacteriana. Es necesario generar evidencia para el desarrollo de políticas antimicrobianas e intervenciones de administración apropiadas y específicas en la pandemia de COVID-19.

Abstract Bacterial co-pathogens are commonly identified in viral respiratory infections and are important causes of morbid-mortality. The prevalence of Chlamydia (C.) pneumoniae infection in patients infected with SARS-CoV-2 has not been sufficiently studied. The objective of the present review was to describe the prevalence of C. pneumoniae in patients with coronavirus disease 2019 (COVID-19). A search in MEDLINE and Google Scholar databases for English language literature published between January 2020 and August 2021 was performed. Studies evaluating patients with confirmed COVID-19 and reporting the simultaneous detection of C. pneumoniae were included. Eleven articles were included in the systematic review (5 case cross-sectional studies and 6 retrospective studies). A total of 18450 patients were included in the eleven studies. The detection of laboratory-confirmed C. pneumoniae infection varied between 1.78 and 71.4% of the total number of co-infections. The median age of patients ranged from 35 to 71 years old and 65% were male. Most of the studies reported one or more pre-existing comorbidities and the majority of the patients presented with fever, cough and dyspnea. Lymphopenia and eosinopenia were described in COVID-19 co-infected patients. The main chest CT scan showed a ground glass density shadow, consolidation and bilateral pneumonia. Most patients received empirical antibiotics. Bacterial co-infection was not associated with increased ICU admission and mortality. Despite frequent prescription of broad-spectrum empirical antimicrobials in patients with coronavirus 2-associated respiratory infections, there is a paucity of data to support the association with respiratory bacterial co-infection. Prospective evidence generation to support the development of an antimicrobial policy and appropriate stewardship interventions specific for the COVID-19 pandemic are urgently required.

Abstract The aim of this communication was to establish if Enterobacterales associated with gulls in Argentina harbored antimicrobial resistance (AMR) genes. We analyzed cloacal swabs in two contrasting areas: Ensenada, Buenos Aires province (26 Larus dominicanus and 22 Chroicocephalus maculipennis) and Puerto Madryn, Chubut province (20 L. dominicanus). In Ensenada, bla CTX-M and mcr-1 genes, were isolated from both gull species, whereas in the Puerto Madryn, only bla CTX-M gene was found. We report for the first time C. maculipennis as carrier of AMR. The finding of AMR in wildlife constitutes a useful tool in evaluating the anthropogenic impact on environmental health.

Abstract The COVID-19 pandemic required rapid development and approval of diagnostic methods and kits. Nasal swab samples (n=1114) were derived to Faculty of Veterinary Sciences- UNLP COVID-19 diagnostic unit by the Buenos Aires Province Ministry of Health during June and July 2020, to perform molecular diagnosis of SARS-CoV-2. Samples of RNA were purified in a type II biosafety cabin and analyzed by real time RT-PCR with the GeneFinder™ kit, which amplifies 3 viral target genes (N, E y RdRp). Of the 1110 samples with positive internal control, 458 (41.2%) were positive (26.9% to all target genes, 4.2% to 2 target genes and almost 10% to one gene, mainly N). Percentage of positive samples remained similar throughout the study period, although the sample number was higher in July (781 samples; 315 positive) compared to June (333 samples; 143 positive). Samples from Berisso, Ensenada and La Plata had significantly lower positive rate than those coming from other counties (27.6% versus 60.7%, respectively). Positivity rate was higher in samples from patients with ≥3 clinical signs (55.6%). It is necessary to conduct inter-laboratory validation studies and standardization of diagnostic methods used in order to obtain reliable and reproducible results.

Resumen La pandemia de la COVID-19 planteó el rápido diseño y aprobación excepcional de diversos métodos de diagnóstico. En la unidad de diagnóstico COVID-19 de la FCV-UNLP, se realizó el diagnóstico molecular de la presencia de SARS-CoV-2 en 1114 hisopados de pacientes derivados por el Ministerio de Salud de la Provincia de Buenos Aires. Las muestras de ARN fueron purificadas en cabina de seguridad y se analizaron mediante real time RT-PCR con el kit GeneFinder™ para tres targets virales (N, E y RdRp). De 1110 muestras con reacción al control interno, 458 (41,2%) fueron reactivas, 26,9% a tres targets virales, 4,2% a dos y cerca del 10% a uno (principalmente N). El porcentaje de positividad fue similar en el tiempo, aunque la cantidad fue mayor en julio (781 muestras; 315 reactivas) respecto a junio (333 muestras; 143 reactivas). Las muestras de Berisso, Ensenada y La Plata presentaron un porcentaje de positividad significativamente menor al de los demás municipios (27,6% versus 60,7%). Las muestras de pacientes con tres o más signos relevantes presentaron una mayor positividad (55,6%) y menor reactividad a un único target. Es necesaria la validación interlaboratorios y la estandarización de los métodos para brindar resultados confiables y reproducibles.

In order to determine the presence and genetic diversity of Chlamydia spp. in the north-eastern area of Buenos Aires province, Argentina, conjunctival, oropharyngeal, cloacal swab and tissues were collected from a total of 90 psittacine pet birds of different age and clinical manifestations. Through molecular methods, Chlamydiaceae was detected in 30% (27/90) of the samples, out of which 70.3% (19/27) were positive for Chlamydia psittaci and 14.9% (4/27) for Chlamydia abortus. Nine C. psittaci positive samples were genotyped by ompA gene sequences, 8 clustered within genotype A and 1 within genotype B. A significant association was observed between the presence of Chlamydia spp. and the manifestation of clinical signs compatible with chlamydiosis, as well as with the age of the birds (younger than one year old). This report contributes to the improvement of our understanding of chlamydial agents in our country.

Con el objetivo de determinar la presencia de Chlamydia spp. en psitácidos del área noreste de la provincia de Buenos Aires y conocer su diversidad genética, se recolectaron y analizaron mediante métodos moleculares hisopados conjuntivales, orofaríngeos, cloacales y tejidos de un total de 90 psitácidos de diferentes edades y con diversas manifestaciones clínicas. El 30% (27/90) de las muestras procesadas fueron positivas para Chlamydiaceae; el 70,3% (19/27) de estas resultaron positivas para Chlamydia psittaci y el 14,9% (4/27) para Chlamydia abortus. Nueve muestras positivas para C. psittaci fueron genotipificadas por secuenciación del gen ompA: 8 correspondieron al genotipo Ay una al genotipo B. Se observó una asociación significativa entre la presencia de Chlamydia spp. y la manifestación de signos clínicos compatibles con clamidiosis, como así también con la edad de las aves (menores de un ano). Este informe contribuye a mejorar nuestro conocimiento de los agentes clamidiales en nuestro país.

In Argentina, the epidemiological and molecular characteristics of Chlamydia psittaci infections are still not sufficiently known. A total of 846 respiratory and 10 ocular samples from patients with suspected human psittacosis were tested for C. psittaci from January 2010 to March 2015. Four samples of birds related to these patients were also studied. Forty-eight samples were positive for C. psittaci by a nested PCR. The molecular characterization of twelve C. psittaci PCR-positive samples received in the National Reference Laboratory INEI-ANLIS "Dr. Carlos G. Malbrán", Buenos Aires, Argentina was performed. Eight positive samples from humans and four from birds were genotyped by ompA gene sequencing. C. psittaci genotype A was found in all human samples and in the related birds. This report contributes to our increasing knowledge of the epidemiological and molecular characteristics of C. psittaci to conduct effective surveillance of its zoonotic infections.

En la Argentina, aún no se conocen suficientemente las características epidemiológicas y moleculares de las infecciones por Chlamydia psittaci. Entre enero del 2010 y marzo del 2015 se estudiaron 846 muestras respiratorias y 10 oculares de pacientes con sospecha de psitacosis para la búsqueda de C. psittaci. También se estudiaron 4 muestras de aves relacionadas con estos pacientes. De ese total, 48 muestras fueron positivas para C. psittaci mediante una reacción en cadena de la polimerasa (PCR) anidada. Posteriormente, se realizó en el INEI-ANLIS «Dr. Carlos G. Malbrán» la caracterización molecular de 12 muestras positivas para C. psittaci, 8 de humanos y 4 de aves, que fueron genotipificadas por secuenciación del gen ompA. C. psittaci genotipo A se encontró en todas esas muestras. Este informe contribuye a mejorar nuestro conocimiento de las características epidemiológicas y moleculares de C. psittaci para lograr una vigilancia efectiva de la zoonosis que produce.

Adult chinchillas (Chinchilla lanigera) that had suddenly died in a commercial farm located in La Plata City, Buenos Aires Province, Argentina, in July 2012 were macroscopically, histopathologically, and microbiologically examined. Salmonella enterica serovar Typhimurium (S. Typhimurium) was isolated from the liver, spleen, heart, lungs, kidneys and intestines from each of the five animals evaluated. The five strains were susceptible to ampicillin, cephalotin, cefotaxime, nalidixic acid, gentamicin, streptomycin, chloramphenicol, fosfomycin, nitrofurantoin and trimethoprimsulfamethoxazole, and resistant to tetracycline. Each of the five S. Typhimurium isolates was analyzed by XbaI- pulsed-field gel electrophoresis (PFGE), showing an identical electrophoretic profile with 15 defined bands, which was found to be identical to pattern ARJPXX01.0220 of the PulseNet Argentine National database of Salmonella PFGE patterns. This is the first work describing the postmortem diagnosis of an outbreak of salmonellosis in chinchillas by using molecular methods such as PFGE.