Identification, phylogenetic analysis, and genome mining of the tetracycline-resistant Bacillus thuringiensis strain m401 reveal its potential for biotechnological and biocontrol applications.

Bacillus thuringiensis is an entomopathogen belonging to the Bacillus cereus clade. We isolated a tetracycline-resistant strain called m401, recovered it from honey, and identified it as Bacillus thuringiensis sv. kumamotoensis based on the average nucleotide identity calculations (ANIb) comparison and the analysis of the gyrB gene sequences of different B. thuringiensis serovars. Sequences with homology to virulence factors [cytK, nheA, nheB, nheC, hblA, hblB, hblC, hblD, entFM, and inhA] and tetracycline resistance genes [tet(45), tet(V), and tet(M)/tet(W)/tet(O)/tet(S) family] were identified in the bacterial chromosome. The prediction of plasmid-coding regions revealed homolog sequences to the MarR and TetR/AcrR family of transcriptional regulators, toxins, and lantipeptides. The genome mining analysis revealed 12 regions of biosynthetic gene clusters responsible for synthesizing secondary metabolites. We identified biosynthetic gene clusters coding for bacteriocins, siderophores, ribosomally synthesized post-translationally modified peptide products, and non-ribosomal peptide synthetase clusters that provide evidence for the possible use of Bt m401 as a biocontrol agent. Furthermore, Bt m401 showed high inhibition against all Paenibacillus larvae genotypes tested in vitro. In conclusion, Bt m401 owns various genes involved in different biological processes, such as transductional regulators associated with antibiotic resistance, toxins, and antimicrobial peptides with potential biotechnological and biocontrol applications.

[Antimicrobial susceptibility in isolates of Streptococcus equi subsp. equi from Buenos Aires province, Argentina]. / Sensibilidad a los antimicrobianos de aislamientos de Streptococcus equi subsp. equi de la provincia de Buenos Aires, Argentina.

Streptococcus equi subsp. equi is the etiologic agent of strangles, an infectious disease affecting the upper respiratory tract and head and neck lymph nodes of equines. Routine antimicrobial therapy includes penicillin (PEN) as antibiotic of first choice. Streptococci are usually susceptible to PEN and only a few antimicrobial studies had been performed. The aim of this work was to study the antimicrobial susceptibility profile of S. equi from Buenos Aires, Argentina. Ninety-two isolates were studied by the single disk method to PEN, cefotaxime, erythromycin (ERY), tetracycline, enrofloxacin (ENR), trimethoprim sulfamethoxazole (TMS), ciprofloxacin, clindamycin (CLI), streptomycin (STR) and florfenicol. Minimum inhibitory concentration (MIC) to PEN and antibiotics with resistance and intermediate susceptibility were tested. High percentages of susceptibility were obtained by the disk diffusion method and MIC values of PEN, TMS and CLI were found to be under the breakpoint values. Resistant strains of ENR and STR with MIC50, MIC90 and MIC ranges above breakpoints were identified. These findings confirm that PEN may be used empirically because resistant strains were not found in Buenos Aires. Emphasis is placed on the rational use of antibiotics to achieve therapeutic success, to prevent chronicity, recurrence of infections and the emergence of resistance.

[Péptidos antimicrobianos, una alternativa prometedora para el tratamiento de enfermedades infecciosas].

Microorganisms that cause diseases in humans are constantly evolving, which represents a challenge in the search for effective treatments against them. Even when currently there are several pharmacological alternatives available, sometimes they are inefficient for the control of infectious diseases, especially because pathogens have generated multiple resistance mechanisms against them. Antimicrobial peptides have been described in many species of organisms, from fungi, plants and insects to humans; currently, there are molecules that appear as a solution that can be effective in modern therapeutics. The advantage of these natural peptides lies in that they have been evolving almost the same amount of time than the species that produce them and their effect on the control of microorganisms is highly significant; some of these molecules are isolated from living organisms, others are starting to be produced by synthetic methods, which allows having access to an endless number of peptides with diverse therapeutic activities.

Los microorganismos causantes de enfermedades en humanos evolucionan constantemente, lo que representa un reto en la búsqueda de tratamientos efectivos contra estos patógenos. Aun cuando en la actualidad se cuenta con diversas alternativas farmacológicas, estas en ocasiones resultan ineficientes para el control de las enfermedades infecciosas, sobre todo porque los patógenos han generado múltiples mecanismos de resistencia. Los péptidos antimicrobianos se han descrito en muchas especies de organismos: hongos, plantas, insectos y humanos; en la actualidad se presentan como una solución terapéutica que puede ser efectiva. La ventaja de estos péptidos naturales es que llevan evolucionando casi la misma cantidad de tiempo que las especies que producen y su efecto en el control de los microorganismos es muy notable; algunas de estas moléculas son aisladas de organismos vivos y otras se comienzan a producir por métodos sintéticos, lo que permite tener acceso a un sinfín de posibles péptidos con actividades terapéuticas diversas.

Identifying priorities to improve paediatric in-hospital antimicrobial use by cross-sectional evaluation of prevalence and appropriateness of prescription.

INTRODUCTION: Information about paediatric in-hospital antimicrobial usage and prescribing patterns to guide improvement strategies is scant. We aim to use an evaluation of the prevalence and appropriateness of antimicrobial prescription to identify antimicrobial stewardship priorities in children. METHODS: A cross-sectional point study was performed on hospitalised paediatric patients in a Spanish tertiary hospital, assessing the prevalence of antimicrobial prescription (PAP) and appropriateness of antimicrobial prescription (AAP). AAP was defined as a correct indication plus an appropriate prescribing pattern (dose, spectrum and interval). Evaluation was performed using established antimicrobial guidelines. Other factors that may have a bearing on antimicrobial prescription were also analysed. RESULTS: A total of 171 patients were included. PAP was 49.7% (85/171) and AAP was 60.9% (91/161). The most common indications for antimicrobial use were antimicrobial prophylaxis (28.3%, 32/113) and pneumonia (8.2%, 8/113). Overall, 161 antimicrobials were prescribed (1.9 antimicrobials per patient): 55.3% (89/161) were empiric, 16.1% (26/161) were targeted and 28.6% (46/161) were prophylactic. Amoxicillin/clavulanate (8.2%, 14/171) and sulfamethoxazole/trimethoprim (8.2%, 14/171) were the most prescribed antimicrobials. The prescription of antifungals (11.7%, 20/171) and antivirals (1.8%, 3/171) was analysed. Major causes of inappropriate antibiotic use were prolonged prescriptions (21.7%, 35/161) and use of agents with an excessively broad coverage spectrum (21.1%, 34/161). PAP and AAP varied between wards and antimicrobials. CONCLUSIONS: Measurement of PAP and AAP offers valuable information for detecting priorities in hospital settings and monitoring antimicrobial usage prior to the development of antimicrobial stewardship programmes. In our setting, the main areas for improvement are duration of therapy and proper use of broad-spectrum antimicrobials.

[Antimicrobial susceptibility of Helicobacter pylori strains isolated from gastric lesions]. / Sensibilidad a los antimicrobianos de aislamientos de Helicobacter pylori aislados de lesiones gástricas.

Antimicrobial susceptibility was evaluated by two diffusion methods: E-test strips to determine minimum inhibitory concentration (MIC) and disk diffusion for amoxicillin, clarithromycin, metronidazole and ciprofloxacin in 30 Helicobacter pylori strains isolated from gastric biopsies. No strains were resistant to amoxicillin, 17% (5/30) were resistant to clarithromycin, 20% (6/30) ciprofloxacin by both methods, and 37% (11/30) to metronidazole by the E-test. Although the number of strains studied was reduced, there was a single mismatch in interpreting susceptibility when both methods were compared; the same mismatch was observed for metronidazole, being categorized as sensitive by the E-test and as intermediate by disk diffusion. No association between the histological type of lesion and the resistance pattern found could be determined.

[Management of odontogenic infections in Primary Care: Antibiotic?] / Manejo de las infecciones odontogénicas en las consultas de atención primaria: ¿antibiótico?

Our aim is to contribute to the rational use of antibiotics prescribed by family doctors when a patient consults for a dental problem. Nowadays we should not ask which antibiotic to give. The question has to be if we need to prescribe antibiotics in front of the most common odontogenic infections seen in our practice. We review the main dental infections, which should be their appropriate management and the role of prevention. We need to know the complexity of the oral microbiome because it?ll depend on the appropriateness of the antibiotherapy, the evolution towards cure or progression of some odontogenic infections. The bacterial plaque, formed by the biofilm, behaves as a barrier to the action of antimicrobials. It?s in the prevention of its development as well as in it mechanical elimination once shaped, in what the family doctor should insist. We must transmit antibiotics don?t heal dental pain.

[Analysis of 117 episodes of enterococcal bacteremia: Study of epidemiology, microbiology and antimicrobial susceptibility]. / Análisis de 117 episodios de bacteriemia por enterococo: estudio de la epidemiología, microbiología y sensibilidad a los antimicrobianos.

Enterococcal bacteremia has acquired considerable importance in recent years, mainly due to an increased number of cases that occur during hospital admission. We describe the episodes of enterococcal bacteremia in adult patients recorded at our hospital. Between January 2000 and December 2013, 117 episodes were analyzed. Sixty one percent (61%) of the patients were male and 39% female. The mean age was 68. Predisposing factors were present in 91% of patients. The primary source of infection was intraabdominal. Enterococcus faecalis was responsible for 65% of the cases; E. faecium for 28%; and other species for 7%. Thirty four percent (34%) of cases were polymicrobial bacteremia. All E. faecalis isolates were susceptible to ampicillin and vancomycin. Eighty eight percent (88%) of E. faecium were resistant to ampicillin and 54% to vancomycin and teicoplanin. In our hospital, Enterococcus is the sixth pathogen causing nosocomial bacteremia, with high incidence of ampicillin and vancomycin-resistant E. faecium.

Prevalence and antibiotic susceptibility of coagulase-negative Staphylococcus species from bovine subclinical mastitis in dairy herds in the central region of Argentina.

Coagulase-negative staphylococci (CNS) are a common cause of bovine subclinical mastitis (SCM). The prevalence of CNS species causing SCM identified by genotyping varies among countries. Overall, the antimicrobial resistance in this group of organisms is increasing worldwide; however, little information exists about a CNS species resistant to antibiotics. The aim of the present study was to genotypically characterize CNS at species level and to determine the prevalence and antibiotic resistance profiles of CNS species isolated from bovine SCM in 51 dairy herds located in the central region of the province of Cordoba, Argentina. In this study, we identified 219 CNS isolates at species level by PCR-restriction fragment length polymorphism of the groEL gene. Staphylococcus chromogenes (46.6%) and Staphylococcus haemolyticus (32%) were the most prevalent species. A minimum of three different CNS species were present in 41.2% of the herds. S. chromogenes was isolated from most of the herds (86.3%), whereas S. haemolyticus was isolated from 66.7% of them. The broth microdilution method was used to test in vitro antimicrobial susceptibility. Resistance to a single compound or two related compounds was expressed in 43.8% of the isolates. S. chromogenes and S. haemolyticus showed a very high proportion of isolates resistant to penicillin. Resistance to two or more non-related antimicrobials was found in 30.6% of all CNS. S. haemolyticus exhibited a higher frequency of resistance to two or more non-related antimicrobials than S. chromogenes.

[Antibiotic resistance: A global crisis]. / Resistencia bacteriana a los antibióticos: una crisis global.

The introduction of antibiotics into clinical practice represented one of the most important interventions for the control of infectious diseases. Antibiotics have saved millions of lives and have also brought a revolution in medicine. However, an increasing threat has deteriorated the effectiveness of these drugs, that of bacterial resistance to antibiotics, which is defined here as the ability of bacteria to survive in antibiotic concentrations that inhibit/kill others of the same species. In this review some recent and important examples of resistance in pathogens of concern for mankind are mentioned. It is explained, according to present knowledge, the process that led to the current situation in a short time, evolutionarily speaking. It begins with the resistance genes, continues with clones and genetic elements involved in the maintenance and dissemination, and ends with other factors that contribute to its spread. Possible responses to the problem are also reviewed, with special reference to the development of new antibiotics.

Detection of Neisseria meningitidis in asymptomatic carriers in a university hospital from Brazil.

Asymptomatic meningococcus carriers in hospitals is a risk factor for acquiring meningococcal disease. Meningococcal carrier (MC) frequency was investigated in oropharyngeal swab samples collected from 200 staff members at a teaching hospital from Brazil. MC prevalence was 9% (95% CI 5-13%). Risk factors associated with MC were: mean age of 26.5 years, male gender, bar attendance frequency and number of persons/house. Of 18 isolated meningococcal strains, 14 were non-group able (NG), 3 corresponded to serogroup B and 1 to serogroup 29E. The frequency of serotypes and serosubtypes was heterogenous, with a slight predominance of serotypes 4 and 7 and serosubtypes P1.7 and P1.5. Most strains (n=13) were susceptible to the antimicrobials tested. The ctrA gene (PCR) was identified in 9 (64.3%) of the 14 NG strains, suggesting virulence in most of the NG isolated strains. Therefore, a constant surveillance of these asymptomatic carriers is required.

[Ceftaroline, a new broad-spectrum cephalosporin in the era of multiresistance]. / Ceftarolina, un nuevo antimicrobiano de amplio espectro en la era de las multirresistencias.

Antimicrobial resistance has increased during the last few years, representing a public health concern. Among Gram-positive organisms, methicillin-resistant Staphylococcus aureus (MRSA) and Streptococcus pneumoniae are paradigms of resistance and of the dispersion of multiresistant clones. Ceftaroline, a broad-spectrum cephalosporin that includes MRSA and penicillin-resistant S. pneumoniae, is the first ß-lactam antibiotic useful in infections due to MRSA. Phase-III clinical trials have demonstrated its efficacy in the treatment of community-acquired pneumonia and in skin and soft tissue infections, which are the current indications for ceftaroline. Due to its microbiological and pharmacological (PK/PD) profiles, these indications could be expanded to include bacteremia, endocarditis, and even osteoarticular infections. Another notable feature is the activity of this drug against Gram-negative bacilli susceptible to third generation cephalosporins, indicating that ceftaroline could be useful when these organisms are suspected or demonstrated in polymicrobial infections. Clinical follow-up of ceftaroline use will more clearly define future ceftaroline indications.

[The antibiotic policy. The Infection Committee and antimicrobial use]. / Política de antibióticos. Comisión de Infecciones y uso de antimicrobianos.

The antibiotic policy is the set of strategies and activities undertaken to organize the antimicrobial treatment in the hospital, and achieve health outcomes for patients. The basic principles are to be direct evidence-based medicine, local epidemiology and freedom for prescribing physicians. An antibiotic policy is now more necessary than ever for clinical, epidemiological and economic reasons. The Infection Committee is responsible for the antibiotics policy in hospitals. Its functions as an advisory body to the medical directorate are the analysis of the epidemiology of the infections in the center, measures for its prevention and control, improving the appropriate use of antimicrobials, training, and knowledge production. To achieve clinical, environmental and economic policy objectives of antibiotics is not easy. The agreement of hundreds of professionals for recommendations on indications, dosage and duration of antibiotic treatment, based on the best scientific evidence and local guides is complex, but it can be done. The key to this is that the Infection Committee develops antimicrobial stewardship through a multidisciplinary team and professional leadership, and has the institutional support to ensure that the proper use of antimicrobials is a priority for the center, and therefore of each of the services involved, and that the team has the resources for antimicrobial stewardship.

[The referral of infectious diseases is a key activity for infectious diseases departments and units, as well as for the hospital]. / La interconsulta de enfermedades infecciosas es una actividad clave para los servicios y unidades de enfermedades infecciosas y para el hospital.

Infectious diseases referrals (IDR) is a core activity of infectious diseases departments, and is certainly the one with the greatest potential impact on the hospital due to their cross-sectional nature, and with the emergence of a bacterial resistance and antimicrobial crisis. However, there is no standard model for IDR, no official training, and evaluation is merely descriptive. Paradoxically IDR are at risk in a health system that demands more quality and efficiency. The aim of this review is to assess what is known about IDR, its definition, key features, objectives, method, and the evaluation of results, and to suggest improvements to this key activity for the infectious diseases departments and the hospital.

['Third day intervention': an analysis of the factors associated with following the recommendations on the prescribing of antibiotics]. / La "intervención del tercer día": análisis de los factores asociados al seguimiento de recomendaciones sobre la prescripción de antibióticos.

INTRODUCTION: Stewardship programs on the use of antibiotics usually include interventions based on non-compulsory recommendations for the prescribers. Factors related to the adherence to expert recommendations, and the implementation of these programmes in daily practice, are of interest. METHODS: A randomized, controlled, multicentre intervention study was performed in 32 hospitalization units. Antibiotic prescriptions were evaluated by an infectious disease specialist on the third day. We describe the implementation of the intervention, the factors associated with adherence to recommendations, and the impact of the intervention. RESULTS: A total of 3,192 interventions were carried out. Information sources used to prepare the recommendations varied significantly between centres. A modification was recommended in 65% of cases: withdrawal (47%), change in administration route (26%), change of drugs or number of antibiotics (27%), and change in dose (5%). Simplification of treatment accounted for 75% of all recommendations. Adherence was 68%, with significant differences between hospitals, and higher when the recommendations consisted of a dose adjustment or change of route, during the first intervention period, and also when recommendations were personally commented on, in addition to writing a note in the clinical chart. We did not find any reduction in antibiotic consumption or variation in the incidence of resistant pathogens. CONCLUSIONS: An important proportion of antibiotic prescriptions may be susceptible to improvement, most of them towards simplification. The adherence to the intervention was high, but significant variations at different centres were observed, depending on the type of recommendation, and the study period. Those recommendations that were personally commented on were more followed more than those only written.

[Carbapenem antibiotics in hospitalised paediatric patients. Adherence to a therapeutic protocol]. / Uso de antibióticos carbapenémicos en enfermos pediátricos hospitalizados. Adecuación de su prescripción a un protocolo terapéutico.

OBJECTIVE: To describe the use of carbapenems in children hospitalised outside intensive care and onco-haematology units, and assess adherence to a therapeutic protocol. PATIENTS AND METHODS: A retrospective observational study was conducted on the use of carbapenems between January 2009 and December 2010. The study included children with a community-acquired infectious disease or a health care-associated infectious disease, and who were admitted to paediatric areas of the Vall d'Hebron University Hospital (Barcelona, Spain), other than intensive care, neonatology and onco-haematology units. Clinical data were collected and antibiotic consumption data were provided by the Pharmacy Department. RESULTS: A total of 51 episodes fulfilled the inclusion criteria. Carbapenem as initial empirical treatment was indicated in 31.4%, and applied as rescue therapy in the remainder. The instructions of the protocol were adhered to in 70.6% of the empirical and 87.5% of the targeted prescriptions (77.6% overall). A better match was found for empirical carbapenem in patients with a previous admission or underlying condition. Factors such as diagnosis, age or antibiotic use prior to admission did not affect the empirical indication of carbapenem. CONCLUSIONS: The establishment of a treatment protocol with carbapenem indications in our centre since 2007 has yielded significantly better results on the appropriateness of the prescription than those obtained in other studies.

Treatment of infections caused by carbapenemase-producing Enterobacteriaceae.

Treatment of infections caused by carbapenemase-producing Enterobacteriaceae (CPE) is currently one of the most important challenges of infectious diseases. The available information is based on in vitro studies, some animal model data and a few case studies and retrospective cohorts; appropriate data are lacking or are very scarce for some old antibiotics that are still occasionally used. Because of the heterogeneity in clinical situations, in specific carbapenemases and in the susceptibility of isolates, individualized treatment decisions must usually be made. Here we review the different antibiotics that might be useful for treating infections caused by CPE.

[Self-assessment of patterns of antibiotic use in a university hospital]. / Autovaloración sobre prescripción de antibióticos en un hospital universitario.

INTRODUCTION: A questionnaire was used to determine the knowledge, attitudes and practices of antibiotic prescribing among doctors at a university hospital. METHODS: An anonymous questionnaire was directly distributed by a staff member of the Infectious Diseases Department. RESULTS: A total of 316 questionnaires were distributed with 100% response rate; antibiotic dose, route of administration, and treatment duration were always adjusted according to site of infection and underlying conditions in 65, 68 and 45%, respectively. Antibiotic de-escalation was recognized as usual practice in 20%; 31 and 10% considered potential microbiological resistances and economical-cost when taking prescription decisions, respectively; 16% admitted often prescribing antibiotics with no clinical indication. There were no major significant differences between staff and training physicians, or between surgical or medical specialists. CONCLUSIONS: The self-perception of physicians and residents in our hospital is that they make improper use of antimicrobials.

[Frequency and antimicrobial resistance of Acinetobacter species in a university hospital of Buenos Aires City]. / Frecuencia de aislamiento y resistencia a los antimicrobianos de Acinetobacter spp. recuperadas de pacientes atendidos en un hospital universitario de la Ciudad Autónoma de Buenos Aires, Argentina.

Two-hundred Acinetobacter isolates belonging to 200 patients admitted to Hospital de Clínicas José de San Martín during the period March 2013-June 2014 were analyzed. The identification was performed by mass spectrometry and was confirmed by molecular methods. Susceptibility to antimicrobials was studied by the Vitek-2 system. A 94% correlation of both identification methods was found. Multidrug resistant Acinetobacter baumannii was the predominant genomic species (92.6%) in hospital-acquired infections, whereas Acinetobacter pitti and Acinetobacter nosocomialis accounted for 3.5% and 0.5% of the isolates recovered, respectively. In community-acquired infections a major predominance of the different genomic species was observed. Acinetobacter johnsonii and A. baumannii are the most frequent species, accounting for 45.9% of the isolates recovered. Resistance to carbapenems and minocycline was only observed in A. baumannii. Mass spectrophotometry was an effective tool for the identification of the different genomic species.

Quality indicators on the use of antimicrobials in critically ill patients.

Quality indicators have been applied to many areas of health care in recent years, including intensive care. However, they have not been specifically developed and validated for antimicrobial use in critically ill patients. Antimicrobials play a key role in intensive care units not only in the prognosis of each individual patient, but also in the development of resistance and changes in the flora in this setting. Evaluating the use of these agents is complex in the intensive care unit, however, because the indications vary greatly and antimicrobial treatment is often changed during admission. We designed and developed specific quality indicators regarding the use of antimicrobials in critically ill patients admitted to the intensive care unit. These indicators are proposed as a tool for application in intensive care units to detect problems in the use of antimicrobials. Future trials are needed, however, to validate these indicators in a large population over time.

Molecular epidemiology of pneumococcal carriage in children from Seville, following implementation of the PCV13 immunization program in Andalusia, Spain.

INTRODUCTION: The 13-valent pneumococcal conjugate vaccine (PCV13) universal vaccination programme was introduced in December 2016 in Andalusia. METHODS: A cross-sectional study was conducted on the molecular epidemiology of pneumococcal nasopharyngeal colonization. A total of 397 healthy children were recruited from primary healthcare centres in Seville for the periods 1/4/2018 to 28/2/2020 and 1/11/2021 to 28/2/2022 (PCV13 period). Data from a previous carriage study conducted among healthy and sick children from 1/01/2006 to 30/06/2008 (PCV7 period), were used for comparison of serotype/genotype distributions and antibiotic resistance rates. RESULTS: Overall, 76 (19%) children were colonized with S. pneumoniae during the PCV13 period and there were information available from 154 isolates collected during the PCV7 period. Colonization with PCV13 serotypes declined significantly in the PCV13 period compared with historical controls (11% vs 38%, p = 0.0001), being serotypes 19F (8%), 3 (1%) and 6B (1%) the only circulating vaccine types. Serotypes 15B/C and 11A were the most frequently identified non-PCV13 serotypes during the PCV13 period (14% and 11%, respectively); the later one increased significantly between time periods (p = 0.04). Serotype 11A was exclusively associated in the PCV13 period with ampicillin-resistant variants of the Spain9V-ST156 clone (ST6521 and genetically related ST14698), not detected in the preceding period. CONCLUSIONS: There was a residual circulation of vaccine types following PCV13 introduction, apart from serotype 19F. Serotype 11A increased between PCV13 and PCV7 periods due to emergence and clonal expansion of ampicillin-resistant genotype ST6521.