Effects of a Primary Care Antimicrobial Stewardship Program on Meticillin-Resistant Staphylococcus aureus Strains across a Region of Catalunya (Spain) over 5 Years.

Primary care antimicrobial stewardship program (ASP) interventions can reduce the over-prescription of unnecessary antibiotics, but the impact on the reduction in bacterial resistance is less known, and there is a lack of available data. We implemented a prolonged educational counseling ASP in a large regional outpatient setting to assess its feasibility and effectiveness. Over a 5-year post-implementation period, which was compared to a pre-intervention period, a significant reduction in antibiotic prescriptions occurred, particularly those associated with greater harmful effects and resistance selection. There was also a decrease in methicillin-resistant Staphylococcus aureus (MRSA) strains and in their co-resistance to other antibiotics, particularly those with an ecological impact.

Changes in Group A Streptococcus emm Types Associated with Invasive Infections in Adults, Spain, 2023.

An increase in invasive group A Streptococcus infection was detected in the northeast of Spain in November 2022. A postpandemic decline in the diversity of circulating emm types involved in invasive group A Streptococcus was observed, along with the emergence of emm49 in this geographic area.

Clinical relevance of viral codetection in infants with respiratory syncytial virus bronchiolitis.

INTRODUCTION: Respiratory syncytial virus (RSV) is the main cause of severe bronchiolitis, especially in infants. The aim of this study is to assess whether codetection of RSV and other respiratory viruses could affect the severity of this infection comparing with unique RSV detection. METHODS: A prospective study from 2016 to 2019 including children under 2 years who were admitted in the Emergency Service of the Hospital Universitari Arnau de Vilanova de Lleida (Spain) was performed. Nasopharyngeal samples from all patients were sent to the laboratory for RSV real-time PCR detection (GeneXpert®). A multiplex PCR that detects other respiratory viruses was done in all RSV-positive samples. Patients'medical records were checked to collect clinical data (hospital length of stay, BROSJOD score, ICU admission, need for ventilatory support or transfer to a reference hospital). Patients were divided in two groups: infants with unique RSV detection and infants with viral codetection. Bivariant analyses were performed to analyze the data obtained. RESULTS: During the period of study 437 RSV bronchiolitis were diagnosed. In 199 of them (177/437; 45,5%) another respiratory virus was detected concomitantly. Bivariant analyses do not show statistically significant differences between both groups. CONCLUSIONS: Viral codetection in infants with RSV bronchiolitis is frequent. However, it does not seems to affect the severity of this infection.

Antibiotic Susceptibility and Clarithromycin Resistance Determinants in Helicobacter pylori in the Northeast of Spain: A One-Year Prospective Study.

Helicobacter pylori is one of the most widespread infections, and it is reaching alarming resistance levels worldwide. The recommended first-line empirical treatment differs according to the local rate of clarithromycin resistance. Macrolide resistance is mainly associated with three point mutations in the 23S rRNA gene. The aim of this study was to describe the antibiotic susceptibility of H. pylori in our healthcare area and the main mechanisms involved in clarithromycin resistance. Gastric biopsies (n = 641) were collected and cultured in a one-year prospective study. Antibiotic susceptibility testing was performed by gradient diffusion. A multiplex real-time PCR test (AllplexTMH.pylori & ClariR Assay, Seegene) was used to detect the most frequent mutations associated with clarithromycin resistance. Overall, 141 isolates were available for antibiotic susceptibility testing. The highest resistance rates were detected in metronidazole and levofloxacin. The rate of clarithromycin resistance was 12.1%, and the associated mutations were A2143G and A2142G. More than half of the clarithromycin-resistant isolates presented high MIC values (>256 mg/L). Tetracycline resistance was not detected, suggesting that therapies that contain tetracycline could be a suitable option. The low clarithromycin resistance rate coupled with the high rates of metronidazole resistance may support the recovery of the classical triple therapy in our healthcare area.

Impact of a Primary Care Antimicrobial Stewardship Program on Bacterial Resistance Control and Ecological Imprint in Urinary Tract Infections.

Antimicrobial stewardship programs (ASPs) are a central component in reducing the overprescription of unnecessary antibiotics, with multiple studies showing benefits in the reduction of bacterial resistance. Less commonly, ASPs have been performed in outpatient settings, but there is a lack of available data in these settings. We implemented an ASP in a large regional outpatient setting to assess its feasibility and effectiveness. Over a 5-year post-implementation period, compared to the pre-intervention period, a significant reduction in antibiotic prescription occurred, with a reduction in resistance in E. coli urinary isolates. ASP activities also were found to be cost-effective, with a reduction in medication prescription.

Detection and pathological role of intestinal protozoa in children.

INTRODUCTION: Intestinal parasites are considered a growing public health problem, being protozoa the main cause of intestinal disease. The objective of our study is to compare the detection of intestinal protozoa by microscopy versus real-time PCR, as well as to determine the most prevalent protozoa in our environment in the paediatric population. METHOD: An observational longitudinal study was carried out, both by microscopy and real time-PCR in stool samples from children (0- 15 years) received from April 2019 to March 2021.Children were classified in two groups according if they had or not had clinical parasitosis. Microscopic examination was performed in all samples using the Ritchie concentration technique with the commercial Mini PARASEP system (Movaco-Grifols®). The presence of Cryptosporidium sp. was evaluated with the modified Ziehl-Neelsen acid-fast stain. The real-time PCR was performed to all samples using the Allplex ™ gastrointestinal parasite panel 4 (Seegene®). RESULTS: During the study period, 500 samples were received, being positive 31 (6.2%) by microscopy and 256 (51.2 %) by PCR. By microscopy, Blastocystis hominis was the most frequently observed (4.8%), followed by Giardia lamblia (1.6%), Dientamoeba fragilis (0.2%) and Cryptosporidium species (0.2%). Regarding the identification by PCR, D. fragilis (35.2%) was mainly identified, followed by B. hominis (28.1%), G. lamblia (7%) and Cryptosporidium sp. (0.8%) without finding clear differences in aetiology according to age. In the case of B. hominis and D. fragilis, there were not differences in the detection of these protozoa between the control group and children with clinical parasitosis (p = 0.11). CONCLUSIONS: Real-time PCR increases the detection of intestinal protozoa, being underdiagnosed by microscopy, especially D. fragilis, in which PCR is considered the most appropriate method for its detection.

Carbapenem Resistance in Acinetobacter nosocomialis and Acinetobacter junii Conferred by Acquisition of blaOXA-24/40 and Genetic Characterization of the Transmission Mechanism between Acinetobacter Genomic Species.

Carbapenem resistance is increasing among Gram-negative bacteria, including the genus Acinetobacter. This study aimed to characterize, for the first time, the development of carbapenem resistance in clinical isolates of Acinetobacter junii and Acinetobacter nosocomialis conferred by the acquisition of a plasmid-borne blaOXA-24/40 gene and also to characterize the dissemination of this gene between species of Acinetobacter. Carbapenem-resistant A. nosocomialis HUAV-AN66 and A. junii HUAV-AJ77 strains were isolated in the Arnau de Vilanova Hospital (Spain). The genomes were sequenced, and in silico analysis were performed to characterize the genetic environment and the OXA-24/40 transmission mechanism. Antibiotic MICs were determined, and horizontal transfer assays were conducted to evaluate interspecies transmission of OXA-24/40. Carbapenems MICs obtained were ≥64 mg/L for HUAV-AN66 and HUAV-AJ77. Genome analysis revealed the presence in both strains of a new plasmid, designated pHUAV/OXA-24/40, harboring the carbapenem-resistance gene blaOXA-24/40 and flanked by sequences XerC/XerD. pHUAV/OXA-24/40 was successfully transferred from A. nosocomialis and A. junii to a carbapenem-susceptible A. baumannii strain, thus conferring carbapenem resistance. A second plasmid (pHUAV/AMG-R) was identified in both clinical isolates for the successful horizontal transfer of pHUAV/OXA-24/40. blaOXA-24/40-carrying plasmids of the GR12 group and showing high identity with pHUAV/OXA-24/40 were identified in at least 8 Acinetobacter species. In conclusion the carbapenemase OXA-24/40 is described for the first time in A. nosocomialis and A. junii. In both isolates the blaOXA-24/40 gene was located in the GR12 pHUAV/OXA-24/40 plasmid. GR12 plasmids are implicated in the dissemination and spread of carbapenem resistance among Acinetobacter species. IMPORTANCE Acinetobacter baumannii is one of the most relevant pathogens in terms of antibiotic resistance. The main resistance mechanisms are the carbapenem-hydrolyzing class D ß-lactamases (CHDLs), especially OXA-23 and OXA-24/40. In addition to A. baumannii, there are other species within the genus Acinetobacter, which in general exhibit much lower resistance rates. In this work we characterize for the first time two clinical isolates of Acinetobacter nosocomialis and Acinetobacter junii, isolated in the same hospital, carrying the carbapenemase OXA-24/40 and displaying high resistance rates to carbapenems. By means of bioinformatics analysis we have also been able to characterize the mechanism by which this carbapenemase is horizontally transferred interspecies of Acinetobacter spp. The dissemination of carbapenemase OXA-24/40 between non-baumannii Acinetobacter species is concerning since it prevents the use of most ß-lactam antibiotics in the fight against these resistant isolates.

Penicillin susceptibility among invasive MSSA infections: a multicentre study in 16 Spanish hospitals.

OBJECTIVES: To determine the prevalence of penicillin susceptibility among MSSA causing bloodstream infections (BSIs) in 16 Spanish hospitals and to characterize the penicillin-susceptible MSSA (MSSA-PENS) isolates. METHODS: A total of 1011 Staphylococcus aureus isolates were collected from blood cultures in 16 Spanish hospitals during 2018-19 (6-12 months) and their susceptibility to 18 antimicrobials was determined. The MSSA-PENS isolates were selected and examined by PCR to determine the presence of the blaZ gene, other resistance genes and the genes lukF/lukS-PV, eta, etb and tst. The immune evasion cluster (IEC) type was also analysed. All the MSSA-PENS isolates were submitted to S. aureus protein A (spa) typing and the clonal complexes (CCs) were assigned according to their spa type. RESULTS: The prevalence of MSSA was 74.6% (754/1011) and 14.9% (151/1011) were MSSA-PENS-blaZnegative. MSSA-PENS-blaZnegative isolates (n = 151) were ascribed to 88 spa types and 11 CCs. The most frequent CCs were CC5 (35/151) and CC398 (25/151), with t002-CC5 and t571-CC398 being the most common lineages. Pan-susceptibility was identified in 117 of the 151 MSSA-PENS-blaZnegative isolates (77.5%). In the remaining isolates, erythromycin and clindamycin resistance was the most frequent resistance found, although tobramycin, ciprofloxacin, fusidic acid, mupirocin and/or tetracycline resistance was also detected. Thirty-eight MSSA-PENS-blaZnegative isolates were IEC negative and four isolates were Panton-Valentine leucocidin ('PVL') positive. CONCLUSIONS: A high penicillin susceptibility rate was detected among MSSA, opening therapeutic opportunities for BSIs. The emergence of new successful MSSA-PENS clones could be responsible for these data. The detection among MSSA-PENS-blaZnegative isolates of the clonal lineage CC398 or the absence of an IEC raises questions about their possible animal origin, requiring further analysis.

E-gene RT-PCR Crossing Point Value and Other Biochemical Parameters as Useful Markers of Death Risk in COVID-19 Patients.

The identification of laboratory markers which predict the outcome of COVID-19 patients is a great concern. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) has been used to confirm the clinical diagnosis. The aim of this study is to evaluate laboratory parameters of COVID-19 patients as well as to evaluate the RT-PCR crossing point (Cp) value and correlate blood test abnormalities and the Cp value with patients survival. Two hundred thirty patients with positive RT-PCR of SARS-CoV-2 were included in the study. Molecular diagnosis of SARS-CoV-2 was performed by RT-PCR (LightMix, TibMolbiol, Germany). Clinical information, biochemical parameters and Cp values were collected in an anonymized database and variables were analyzed with SPSS v25.0 (IBM Corporation, Armonk, NY, USA). No-survivors were significantly older (>65 years old) than survivors (p=0.007). A higher prevalence of cardiovascular comorbidities in patients who died than in those who survived was found (p=0.002). Statistically significant differences were obtained comparing RT-PCR Cp values for the E-gene of patients who died and those who survived, being lower (<=28) those of patients who died (p=0.004). No-survivors had significantly higher levels of CRP (>100) (p=0.007). E-gene Cp values <=28, which correlate with a high number of copies of SARS-CoV-2, as well as several demographical and biochemical parameters (Age above 65 years old, CRP levels >100 mg/L or cardiovascular comorbidities) could be useful markers of death risk in these patients.

Prevalence and Genetic Characteristics of Staphylococcus aureus CC398 Isolates From Invasive Infections in Spanish Hospitals, Focusing on the Livestock-Independent CC398-MSSA Clade.

BACKGROUND: Livestock-associated (LA)-CC398-MRSA is closely related to pigs, being unfrequently detected in human invasive infections. CC398-MSSA is emerging in human invasive infections in some countries, but genetic and epidemiological characteristics are still scarcely reported. OBJECTIVES: To determine the prevalence of Staphylococcus aureus (SA) CC398, both MRSA and MSSA, among blood cultures SA isolates recovered in Spanish hospitals located in regions with different pig-farming densities (PD) and characterize the recovered isolates. METHODS: One thousand twenty-two SA isolates (761 MSSA, 261 MRSA) recovered from blood cultures during 6-12 months in 17 Spanish hospitals (2018-2019) were studied. CC398 lineage identification, detection of spa-types, and antibiotic resistance, virulence and human immune evasion cluster (IEC) genes were analyzed by PCR/sequencing. RESULTS: Forty-four CC398-MSSA isolates (4.3% of SA; 5.8% of MSSA) and 10 CC398-MRSA isolates (1% of SA; 3.8% of MRSA) were detected. Eleven spa-types were found among the CC398-MSSA isolates with t571 and t1451 the most frequent spa-types detected (75%). Most of CC398-MSSA isolates were Immune-Evasion-Cluster (IEC)-positive (88.6%), tetracycline-susceptible (95.5%) and erythromycin/clindamycin-inducible-resistant/erm(T)-positive (75%). No statistical significance was detected when the CC398-MSSA/MSSA rate was correlated to PD (pigs/km2) (p = 0.108). On the contrary, CC398-MRSA isolates were all IEC-negative, predominately spa-t011 (70%), and the CC398-MRSA/MRSA rate was significantly associated to PD (p < 0.005). CONCLUSION: CC398-MSSA is an emerging clade in invasive infections in Spanish hospitals. CC398-MRSA (mostly t011) and CC398-MSSA (mostly t571 and t1451) show important differences, possibly suggesting divergent steps in host-adaptation evolutionary processes. While CC398-MRSA is livestock-associated (lacking IEC-system), CC398-MSSA seems to be mostly livestock-independent, carrying human-adaptation markers.

Mechanisms of Linezolid Resistance Among Clinical Staphylococcus spp. in Spain: Spread of Methicillin- and Linezolid-Resistant S. epidermidis ST2.

This study aimed at determining the mechanisms of linezolid resistance and the molecular characteristics of clinical Staphylococcus aureus (n = 2) and coagulase-negative staphylococci (n = 15) isolates obtained from four Spanish hospitals. The detection of linezolid resistance mechanisms (mutations and acquisition of resistance genes) was performed by PCR/sequencing. The antimicrobial resistance and virulence profile was determined, and the isolates were typed by different molecular techniques. Moreover, the genetic environment of the cfr gene was determined by whole-genome sequencing. The cfr gene was detected in one methicillin-resistant S. aureus (MRSA) that also displayed the amino acid change Val118Ala in the ribosomal protein L4. The second S. aureus isolate was methicillin susceptible and showed different alterations in the ribosomal protein L4. All remaining linezolid-resistant Staphylococcus epidermidis (n = 14) and Staphylococcus hominis isolates (n = 1) showed the mutation G2576T (n = 14) or C2534T (n = 1) in the 23S rRNA. Moreover, different amino acid changes were detected in the ribosomal proteins L3 and L4 in S. epidermidis isolates. All S. epidermidis isolates belonged to the multilocus sequence type ST2. Linezolid-resistant staphylococci (LRS) showed a multiresistance phenotype, including methicillin resistance that was detected in all isolates but one, and was mediated by the mecA gene. The cfr gene in the MRSA isolate was located together with the fexA gene on a conjugative 38,864 bp plasmid. Linezolid- and methicillin-resistant S. epidermidis ST2 showing mutations in the 23S rRNA and in the ribosomal proteins L3 and L4 are spread among Spanish hospitals, whereas LRS carrying acquired linezolid resistance genes are rarely detected.

Detection of a cfr-positive MRSA CC398 strain in a pig farmer in Spain.

OBJECTIVE: To characterize one linezolid- and methicillin-resistant Staphylococcus aureus (MRSA) isolate recovered from a nasal sample of a pig farmer patient. METHODS: The detection of linezolid resistance mechanisms was performed by PCR and sequencing. The antimicrobial resistance and virulence profile was investigated, and the molecular typing was performed by molecular techniques. The transference of cfr gene was assessed by conjugation experiments and its genetic environment was investigated by specific PCRs. RESULTS: The linezolid-resistant MRSA isolate was typed as t011-ST398/CC398-SCCmecV-agrI and carried the cfr gene. The isolate was multidrug-resistant but lacked the virulence genes studied. The cfr gene was co-located with the fexA gene on a Tn558 variant and was successfully transferred by conjugation. CONCLUSION: We report the first description of LA-MRSA-CC398 carrying the cfr gene in Spain. This finding highlights the importance of surveillance programmes to determine the presence and spread of the cfr gene in the livestock and clinical settings.

Entamoeba histolytica liver abscess case: could stool PCR avoid it?

Background Liver abscess is the most common extraintestinal manifestation of Entamoeba histolytica. Clinical manifestations could appear after returning from an endemic area or several years after the exposure. The diagnosis usually requires microbiological confirmation. Case presentation We present a case of a 55-year-old woman diagnosed with Crohn's disease treated with immunosuppressive drugs, who was admitted to the Emergency Service with liver parenchyma abscesses. Computed tomography (CT)-guided puncture showed pus, and both Gram staining and fresh parasite visualization were negative. Hepatic pus bacteriological culture was reported as negative and parasite multiplex polymerase chain reaction (PCR) was performed, being positive for E. histolytica. The same PCR was performed on blood, pleural fluid and stool samples, all of them being positive for E. histolytica. Conclusions Reviewing the clinical history of this patient, it was observed that parasite detection in three stool samples was negative 2 months before the current admission. Due to the lack of sensitivity of the microscopy techniques, we propose to routinely perform parasite detection in stools using molecular techniques, especially in immunocompromised patients.

Pseudomonas aeruginosa Isolates from Spanish Children: Occurrence in Faecal Samples, Antimicrobial Resistance, Virulence, and Molecular Typing.

Pseudomonas aeruginosa is a major opportunistic human pathogen, responsible for nosocomial infections and infections in patients with impaired immune systems. Little data exist about the faecal colonisation by P. aeruginosa isolates in healthy humans. The occurrence, antimicrobial resistance phenotype, virulence genotype, and genetic lineages of P. aeruginosa from faecal samples of children from two different Spanish regions were characterised. Seventy-two P. aeruginosa were isolated from 1,443 faecal samples. Low antimicrobial resistance levels were detected: ceftazidime (8%), cefepime (7%), aztreonam (7%), gentamicin (3%), ciprofloxacin (1%), and imipenem (1%); susceptibility to meropenem, amikacin, tobramycin, levofloxacin, and colistin. Four multidrug-resistant strains were found. Important differences were detected between both geographical regions. Forty-one sequence types were detected among the 48 tested strains. Virulence and quorum sensing genes were analysed and 13 virulotypes were detected, being 26 exoU-positive strains. Alteration in protein OprD showed eight different patterns. The unique imipenem-resistant strain showed a premature stop codon in OprD. Intestinal colonisation by P. aeruginosa, mainly by international clones (as ST244, ST253, and ST274), is an important factor for the systemic infections development and the environmental dissemination. Periodic active surveillance is useful to identify these community human reservoirs and to control the evolution of antibiotic resistance and virulence activity.

Characterisation of VIM-2-producing Pseudomonas aeruginosa isolates from lower tract respiratory infections in a Spanish hospital.

To analyse the antimicrobial phenotype, carbapenem mechanisms, integrons, virulence factors and molecular typing of 164 Pseudomonas aeruginosa isolates recovered from lower tract respiratory samples in a Spanish hospital (1 year) as well as the patients' clinical data. Susceptibility testing to 12 antipseudomonal agents was determined by microdilution and metallo-beta-lactamase (MBL) phenotype by double disc method. The oprD gene was studied by PCR, sequencing and comparison with P. aeruginosa PAO1 sequence. Detection and characterisation of MBLs, class 1, 2 and 3 integrons, and virulence genes were studied by PCR and sequencing. The prevalence of carbapenem-resistant P. aeruginosa (CRPA) was 26.8%. MBL phenotype was detected in 52.3% CRPA, and all of them were disseminated throughout the intensive care unit. Most of the MBL-carrying patients presented respiratory disease, mechanical ventilation, tracheostomy, bacteraemia, ≥ 30 hospitalisation days and previous treatment with carbapenems and/or ≥ 3 different antimicrobial families. The blaVIM-2 gene was the unique MBL encoding gene and was detected inside class 1 integrons. The class 1 integrons detected in 39 strains (23.8%) were associated with aminoglycosides (aadB, aadA1, aadA6, aacA4, aac(3)-I) and carbapenems resistance genes (blaVIM-2). The aac(3)-I + aadA1 and blaVIM-2 arrangements were the most prevalent ones. Thirty-one different PFGE patterns and 4 STs (ST175, ST235, ST253, ST973) were detected among the 39 intI1-positive isolates, being ST235 the most frequent. CRPA showed a great variety of alterations in oprD gene. The exoU+/exoS- genotype was detected in 82.6% of blaVIM-2-producing strains (ST235) and the exoU-/exoS+ in the remaining 17.4% (ST973).