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Objectives: To describe at genomic level nine carbapenemase-producing Klebsiella pneumoniae ST307 (Kp-ST307) clinical isolates recovered in Buenos Aires during 2017 to 2021, investigating their resistome, virulome, and phylogeny., Methods: Antimicrobial susceptibility was determined according to Clinical and Laboratory Standards Intitute (CLSI). Genomic DNA was sequenced by Illumina MiSeq and analysed using SPAdes, PROKKA, and Kleborate. Phylogeny of 355 randomly selected Kp-ST307 genomes and those from nine local isolates was inferred by a maximum-likelihood approach. The tree was visualized using Microreact., Results: Besides resistance to ß-lactams and fluoroquinolones, six out of nine Kp-ST307 were also resistant to ceftazidime/avibactam (CZA). This difficult-to-treat resvistance phenotype was mediated by bla SHV-28 and GyrA-83I/ParC-80I mutations in addition to carbapenemase coding genes. Among CZA susceptible isolates, two of them harboured bla KPC-3 while the other harboured bla KPC-2 +bla CTX-M-15. Regarding CZA-resistant isolates, three harboured bla KPC-3 +bla NDM-1 +bla CMY-6 , two carried bla KPC-2 +bla NDM-5 +bla CTX-M-15 , and bla NDM-5 +bla CTX-M-15 were detected in the remaining isolate. Furthermore, five colistin-resistant isolates presented a nonsense mutation in mgrB. Global Kp-ST307 isolates were distributed in two deep-branching lineages while local isolates were set in the main clade of the phylogenetic tree. The five isolates from the same hospital, harbouring bla KPC-3 or bla KPC-3 +bla NDM-1 +bla CMY-6 , clustered in a monophyletic subclade with Italian isolates. Also, an isolate harbouring bla KPC-2 +bla NDM-5 +bla CTX-M-15 recovered in another hospital was closed to this group. The remaining local Kp-ST307 were grouped in other subclades containing isolates of diverse geographical origin., Conclusion: The inferred resistome was consistent with the resistant phenotype. Phylogeny suggested multiple introduction events in our region and a single major introduction in one hospital followed by local spread., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Clostridioides difficile is a spore-forming anaerobe microorganism associated to nosocomial diarrhea. Its virulence is mainly associated with TcdA and TcdB toxins, encoded by their respective tcdA and tcdB genes. These genes are part of the pathogenicity locus (PaLoc). Our aim was to characterize relevant C. difficile toxinotypes circulating in the hospital setting. The tcdA and tcdB genes were amplified and digested with different restriction enzymes: EcoRI for tcdA; HincII and AccI for tcdB. In addition, the presence of the cdtB (binary toxin) gene, TcdA and TcdB toxins by dot blot and the cytotoxic effect of culture supernatants on Vero cells, were evaluated. Altogether, these studies revealed three different circulating toxinotypes according to Rupnik's classification: 0, I and VIII, being the latter the most prevalent one. Even though more studies are certainly necessary (e.g. sequencing analysis), it is worth noting that the occurrence of toxinotype I could be related to the introduction of bacteria from different geographical origins. The multivariate analysis conducted on the laboratory values of individuals infected with the most prevalent toxinotype (VIII) showed that the isolates associated with fatal outcomes (GCD13, GCD14 and GCD22) are located in regions of the biplots related to altered laboratory values at admission. In other patients, although laboratory values at admission were not correlated, levels of urea, creatinine and white blood cells were positively correlated after the infection was diagnosed. Our study reveals the circulation of different toxinotypes of C. difficile strains in this public hospital. The variety of toxinotypes can arise from pre-existing microorganisms as well as through the introduction of bacteria from other geographical regions. The existence of microorganisms with different pathogenic potential is relevant for the control, follow-up, and treatment of the infections., (Copyright © 2022 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

MDR Klebsiella pneumoniae ST307 is a high-risk clone, whose genetic features contribute to its adaptation to hospital environments and the human host. This study describes the emergence and clonal dissemination of K. pneumoniae ST307, recovered during November 2018 to February 2019 in a hospital in Buenos Aires city, which concurrently harbored KPC-3 and NDM-1. These isolates were resistant to all β-lactams and to the ceftazidime/avibactam combination. Molecular studies showed that bla KPC-3 was located in Tn4401a platform, while bla NDM-1 was surrounded upstream by ISKpn14 followed by a partial sequence of ISAba125 and downstream by bleMBL-trpF, located in a 145.5kb conjugative plasmid belonging to the Inc A/C group. The dissemination of K. pneumoniae ST307 isolates co-producing KPC-3 and NDM-1 could lead to a worrisome scenario due to the remarkable features of this clone and its resistance profile., (Copyright © 2022 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Objectives: To assess the epidemiological features of 76 Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (KPC-Kp) isolates recovered from three hospitals in Buenos Aires, Argentina, during 2015-2017., Methods: Antimicrobial susceptibilities were determined according to CLSI Clinical and Laboratoy Standards guidelines. Molecular typing of KPC-Kp was performed by pulsed-field gel electrophoresis (PFGE)-Xbal and multilocus sequence typing. Plasmid encoded genes involved in carbapenem, fosfomycin and colistin resistance were detected by polymerase chain reaction (PCR) and sequencing. Also, mgrB inactivation was investigated in those colistin-resistant isolates. Genetic platforms involved in horizontal spread of bla KPC were investigated by PCR mapping., Results: Besides β-lactams, high resistance rates were observed for gentamycin, quinolones and trimethoprim-sulfamethoxazole. KPC-Kp sequence type (ST)258 corresponded to 26% of the isolates, while 42% corresponded to ST25. The other isolates were distributed in a diversity of lineages such as ST11 (10.5%), ST392 (10.5%), ST307, ST13, ST101, ST15 and ST551. bla KPC-2 was detected in 75 of 76 isolates, and one ST307 isolate harboured bla KPC-3 . Tn4401 was identified as the genetic platform for bla KPC in epidemic lineages such as ST258 and ST307. However, in ST25 and ST392, which are usually not related to bla KPC , a bla KPC -bearing non-Tn4401 element was identified. Alterations in mgrB were detected in seven of 11 colistin-resistant isolates., Conclusions: Despite previous reports in Argentina, ST258 is no longer the absolute clone among KPC-Kp isolates. In the present study, dissemination of more virulent lineages such as the hypermucoviscous ST25 was detected. The emergence of the high-risk clone ST307 and occurrence of bla KPC-3 was noticed for the first time in this region., (Copyright © 2019 International Society for Antimicrobial Chemotherapy. Published by Elsevier Ltd. All rights reserved.)

Ten IMP-8-producing Escherichia coli isolates were recovered from surveillance cultures of a neonatal intensive care unit; eight of the isolates were clonally related. A 168.2-kb bla IMP-8 plasmid was fully sequenced, and it corresponded to the recently described IncA/C1-ST13 plasmid. This plasmid was detected in all isolates, even in those that were not clonally related. One unrelated isolate was also resistant to colistin and positive for mcr-1 This marker was located in a 62.7-kb IncI2 plasmid, which was also fully sequenced., (Copyright © 2018 American Society for Microbiology.)

Objective: Ocular infection in neonatology is a permanent and important health problem. To improve primary attention, prevention, and control, the study of the potential bacterial etiology of all consecutive cases of conjunctivitis was incorporated as a regular procedure in primary care from July 1995 to December 1998., Materials and Methods: Prof. A. Posadas Hospital (Great Buenos Aires) has an average of 4294 births per year. This report analyzes the results obtained in 332 infants (age range, 0-30 d) with conjunctivitis. Clinical conjunctivitis was diagnosed in inpatients and outpatients by the same specialized staff. Isolation and characterization of bacteria were done by conventional microbiologic methods, including specific search for Neisseria gonorrhoeae and Chlamydia trachomatis. Chlamydia trachomatis was studied by antigen immunodetection and polymerase chain reaction, and genotyped by restriction fragment length polymorphism., Results: Conjunctivitis had an incidence (cases per 1000 live births) of 39.6 in 1995, 25.3 in 1996, 15.4 in 1997, and 15.2 in 1998. Microbial growth was detected in 167 (50.3%) of 332 cases. Ocular C. trachomatis infection was detected in 26 cases (7.83%). Five of seven isolates in tissue cultures belonged to type E and two to type G. Bacteria from respiratory ecology were the main isolates: Haemophilus influenzae (16.9%), Streptococcus pneumoniae (12.3%), and Staphylococcus aureus (8.7%). Haemophilus influenzae isolates were not serotyped and 17.2% of them were b-lactamase producers. In 15 cases both H. influenzae and S. pneumoniae were isolated together. Of S. pneumoniae, 4.9% were oxacillin resistant., Conclusions: There has been a decline in the total number of cases of neonatal conjunctivitis, but the disease is still an important health problem. Chlamydia trachomatis also shows a decreasing profile with an incidence of (cases per 1000 live births) 4.39 in 1995, 1.85 in 1996, 1.01 in 1997, and 0.78 in 1998, and a tendency to show more incidence in spring-summer and significant accumulation of cases in babies between 7 and 9 days of age. Haemophilus influenzae alone (12.3%) or associated with S. pneumoniae (4.5%) appears as a prevalent potential bacterial pathogen. A significant accumulation of H. influenzae and S. pneumoniae cases occurs in winter. In 47.6% of cases, there was no bacterial growth. No significant seasonal differences in percentage of negative cultures or among the three-day age groups were detected. Neisseria gonorrhoeae was not found associated with ophthalmia neonatorum in this series.

Serum prolactin (PRL) levels were measured in 147 males. All patients had no known tumor, endocrine disorder, or symptoms or signs of hyperprolactinemia. All patients denied taking any medication or agents that could alter PRL levels. Semen analyses revealed 34 patients were normospermic, 69 were oligospermic, 26 were azoospermic, and 18 were purely astenzoospermic. PRL levels for the patient groups were not statistically significantly different. PRL values were higher than the normal ranges in 12.2% of the overall study population. A lower incidence (6.19%) was observed for hyperprolactinemia in the normospermics. These findings are comparable to those described elsewhere. Serum testosterone did not drop significantly in the hyperprolactinemics. Similarly, the FSH and LH values did not change significantly. The possible role of PRL in male infertility and the effect of hyperprolactinemia of varying degrees and etiology on sperm count and motility are discussed.

Massive polyuria existing in congenital nephrogenic diabetes insipidus can cause a more or less severe dilatation of the urinary tract in absence of obstruction. Clinical and diagnostic aspects of this pathology are presented relating then with other types of diabetes insipidus. One case of bilateral severe dilatation with evolution towards renal atrophia is presented. Mechanical obstruction was discarded. The disease was refractory to urinary concentration tests and therapy to reduce urine volume. The possible etiopathological mechanisms of functional obstruction and surgical alternatives directed to preserve the kidney function are explained and discussed. The current literature is reviewed but the cases reported are few due to the low incidence of urological affectation. Presence of kidney atrophia is exceptional.