Antimicrobial Susceptibility Profiles Research Articles

Prevalence and antimicrobial susceptibility profile of uropathogens in dogs and cats with signs of urinary tract infection.

To determine the prevalence of uropathogens in dogs and cats with signs of urinary tract infection and to characterise their antimicrobial susceptibility. Urine samples from canine and feline patients with clinical signs of urinary tract infection were collected between September 2015 and December 2019 in Santiago, Chile. Bacterial identification and bacterial susceptibility profile was performed through biochemical and antimicrobial susceptibility tests. Four hundred sixty-six samples from dogs (37.7%) and 152 from cats (26.1%) showed bacterial growth. Positive samples were mainly from females (dogs: 52.8%; cats: 48.0%), with the highest infection rates in senior dogs (57.7%) and adult cats (45.4%). A single organism caused the infection in 78.2% of the cases, whereas the remaining 21.8% corresponded to a mixed infection. The most prevalent isolated pathogen in dogs and cats was Escherichia coli (42.6% and 49.7%, respectively). Staphylococcus spp. (15.6% and 14.6%), Enterococcus spp. (8.6% and 15.2%) and Proteus spp. (9.7% and 6.4%) were also commonly isolated. A total of 52.4% of Escherichia coli isolates were resistant to amoxicillin, 44.3% to amoxicillin/clavulanic acid, 40.0% to cephradine and 25.3% to ciprofloxacin. Regarding the other three uropathogens commonly isolated in this study, all of them showed a percentage of resistance to the antimicrobials analysed. In addition, 24.6% of multidrug resistance was detected in the E. coli isolates. Penicillin, cephalosporins and fluoroquinolones showed the lowest susceptibility levels. The observed high rates of resistance to commonly prescribed antimicrobials raise concerns for public health.

Bacterial profile and antimicrobial susceptibility patterns of common neonatal sepsis pathogens in Gulf Cooperation Council countries: A systematic review and meta-analysis

Introduction: Neonatal sepsis (NS) is a major healthcare burden in Gulf Cooperation Council (GCC) countries, with a prevalence higher than the global average. Microbial drug resistance has major implications for mortality and morbidity from NS. Objective: To synthesize data regarding the patterns of causative bacteria of NS in the GCC and their antimicrobial susceptibility profiles. Methods: Following the exploration of four electronic databases, i.e., EBSCOhost, ProQuest, PubMed/MEDLINE, and ScienceDirect, eligible studies were identified (i.e., published between 2013 and 2023 and reported bacterial profile and/or antimicrobial susceptibility patterns). The outcomes included the pooled prevalence of bacteria and their susceptibility patterns. Proportion meta-analysis was performed for each outcome of interest. Results: Fifteen studies were eligible (total positive cases = 2,473). Coagulase-negative Staphylococci (CoNS) (28.1%) were the most common gram-positive causative pathogen, followed by group B Streptococcus (GBS) (16.2%) and Staphylococcus aureus (9.9%); for gram-negative, Escherichia coli (12.7%) and Klebsiella species (11.4%) were most common. The susceptibility rates of these bacteria to first-line antibiotics were high; gram-positive bacteria had the highest susceptibility to ampicillin (72.8–98%), and gram-negative bacteria was most susceptible to amikacin (94.6–98%). Additionally, both gram-positive (67–77%) and negative (87–93%) bacteria exhibited high susceptibility to gentamicin. Conclusion: The most common pathogens among NS patients were gram-positive. The pathogens, irrespective of stain test, were susceptible to the current antibiotic therapy. We recommend the judicious use of empirical antibiotic therapy to prevent the growing risk of antimicrobial resistance.

Antimicrobial resistance, virulence factors and phylogenetic profiles of Vibrio parahaemolyticus in the eastern coast of Shenzhen

Vibrio parahaemolyticus (V. parahaemolyticus) is a major food-borne pathogen which causes human gastroenteritis. Since the characteristics of V. parahaemolyticus remain unknown, 220 isolates selected from clinical and environmental samples in Dapeng of Shenzhen were tested for the presence of two hemolysin-expressing genes tdh and trh. Among 27 clinical isolates, 26 carrired the tdh gene, and the other one carried both tdh and trh genes, however neither genes were detected in environmental isolates. Meanwhile, antimicrobial susceptibility profiles revealed the isolates with high frequency of resistance to ampicillin (77.73%) and colistin (71.82%) and medium to streptomycin (57.27%). Genetically, by whole genome sequencing (WGS), comparative genomics studies was performed on isolates from various districts and GenBank. Data analysis showed that antimicrobial resistance genes (ARGs) blaCARB, tet(34) and tet(35) were harbored in all genomes and other ARGs was absent in the genomes of 27 clinical isolates. Besides, little regional difference was observed. As for virulence factors, MAM7, T3SS1, T3SS1 secret effector, T3SS2, T3SS2 secret effector, and VpadF were carried by most isolates. Two isolates from other districts were tdh gene positive which clustered with clinical isolates from Dapeng in the same clade, indicating close genetic distance. This study revealed the widely distribution of V. parahaemolyticus in Shenzhen and the diverse ARGs and virulence genes it carried. Furthermore, pathways that pathogen disseminated through were discussed.

Antimicrobial Susceptibility Profile of Bacteria Isolated from Hemocultures of Patients Attended in a Campaign Hospital During COVID-19 Pandemic

Introduction: Primary bloodstream infections are most commonly related to health care and are associated with intravascular devices, increasing patient mortality, length of stay, and health care costs. Among the complications of hospitalizations for COVID-19, bloodstream infection is one of the most prevalent, requiring prevention and early treatment. Due to the contingency of hospital resources during the pandemic, understanding the prevalence and incidence of antimicrobial agents that cause bloodstream infections and using exams judiciously are essential public health measures, avoiding the misuse of antimicrobials and being able to establish treatment. Objective: This study aimed to determine the antimicrobial susceptibility profile and the prevalence of etiological agents of bloodstream infections in patients with COVID-19 at the field hospital in the city of São Bernardo do Campo - SP. Method: A descriptive, observational, and retrospective cross-sectional study was carried out on the results of blood cultures already collected for diagnostic purposes from patients from May to August 2020 at the same hospital. Results: Of the 300 blood cultures analyzed, 73.7% of the samples showed no bacterial growth. Among the others, the main bacteria found were Klebsiella pneumoniae, sensitive to tigecycline, present in 30 (10%), followed by Staphylococcus sp. (coagulase-negative, non-lugdunensis), sensitive only to doxycycline, gentamicin, tetracycline, and vancomycin, in only 2 (14.3%) samples. Conclusion: In this study, a low rate of laboratory-confirmed bacterial coinfection was identified in patients with COVID-19.

Molecular insights into antimicrobial resistant Staphylococcus aureus strains: A potential zoonosis of goat origin

Antimicrobial-resistant (AMR) Staphylococcus aureus (S. aureus) strains have attained global attention due to their life-threatening zoonotic nature. Being a member of ESKAPE group, S. aureus has an ability to escape the biocidal action of antimicrobial drugs. The current study investigated the prevalence and molecular characterization of methicillin-resistant S. aureus (MRSA), β-lactam-resistant S. aureus (BRSA), aminoglycoside-resistant S. aureus (ARSA), tetracycline-resistant S. aureus (TRSA), and fluoroquinolones-resistant S. aureus (FRSA) associated with goat subclinical mastitis (SCM). Furthermore, the antimicrobial resistance and susceptibility profile of various antibiotics and non-antibiotics (NSAIDs, nisin, N-acetylcysteine, vitamin-C) along with their possible role in modulating the antibiotic resistance of MDR isolates was also investigated. A total of 768 goat milk samples were subjected to California mastitis test for SCM followed by bacteriological and molecular characterization of S. aureus. Moreover, in-vitro susceptibility of resistant antibiotics, non-antibiotics, and their combination against MDR S. aureus were conducted through well diffusion and broth microdilution assays. The results depicted that 55.47% and 26.82% of milk samples were positive for SCM and S. aureus, respectively. The molecular assay confirmed 35.92% of isolates as MRSA, 45.63% as BRSA, 50.49% as ARSA, and 32.52% but no isolate was confirmed as FRSA on molecular basis. The multidrug resistance was observed in 62.13% and 47.09% isolates, respectively. Molecular characterized MDR S. aureus revealed high homology of study isolates with the isolates of neighboring countries like India, Korea, Iran, and China. Antimicrobial susceptibility trials on well diffusion assay showed higher efficacy of different non-antibiotics with resistant antibiotics as penicillin with ketoprofen and gentamicin with flunixin meglumine while oxytetracycline with N-acetylcystiene. The synergy testing by checkerboard assay revealed synergistic activity of penicillin with ketoprofen, gentamicin with flunixin meglumine, and oxytetracycline with N-acetylcysteine. The current study highlighted the emergence and spread of AMR S. aureus strains from goat SCM and provided insights into possible drug repurposing of various non-antibiotics to modulate the multidrug resistance of S. aureus which will be helpful in devising the therapeutic options and control measures for this pathogen.

Identification and antimicrobial susceptibility profiles of Campylobacter isolated from camel at municipal abattoirs in eastern Ethiopia

Campylobacteriosis is an infectious zoonotic disease caused by the genus Campylobacter. The disease is transmitted from animals to humans predominantly through the consumption of contaminated food and water. However, the lack of information on the status of Campylobacter makes it difficult to quantify the role of camel meat in the dissemination of the pathogen. A cross-sectional study was conducted from June 2022 to August 2023 to investigate the occurrence of Campylobacter and associated risk factors and to determine the antimicrobial susceptibility profiles of Campylobacter species from camels slaughtered at municipal abattoirs in the towns of Harar, Babile, Jigjiga and Dire Dawa in eastern Ethiopia. A total of 324 (146 carcass swabs, 146 camel feces and 32 abattoir environmental swab samples) were collected and analyzed using TaqMan real-time PCR and culture techniques following standard procedures. In addition, antimicrobial susceptibility tests were performed using the disk diffusion method for eight antimicrobial agents according to the Clinical Laboratory Standards Institute. The overall prevalence of Campylobacter was 7.7%. Campylobacter was more frequently detected from carcasses and surface contact environmental swabs. We isolated Campylobacter at the genus level from approximately half of the PCR-positive samples, representing 54.2% (13 out of 24) of the total. The isolation levels of C. jejuni and C. coli were also 5.56% and 2.2%, respectively, which varied significantly (p = 0.037) based on sample type and site. The odds of occurrence of C. jejuni in samples collected from abattoir environments was 7.52 times greater than those in carcass and fecal samples. We detected resistance to chloramphenicol (78.6%), followed by amoxicillin (71.4%). However, 93%, 78.6%, and 71.4% of the isolates were susceptible to ceftriaxone, ciprofloxacin, and nalidixic acid, respectively. Multidrug resistance (MDR) was detected in 60% of the isolates. Of these MDR isolates, 9 (75%) were C. jejuni and 3 (25%) were C. coli. This study revealed that a considerable proportion of multidrug-resistant Campylobacter species circulate in both camel meat and abattoir environments. This indicates possible carcass cross-contamination by Campylobacter during slaughtering that can pose a threat to humans and limit therapeutic options, which could be prevented by applying good hygienic practices at abattoirs. Therefore, abattoir workers need to be aware of abattoir hygienic standard operating procedures. Regular coordinated actions should be implemented for the rational use of veterinary and medical drugs at the national level, together with training and awareness of hygienic practices.

Prevalence of Salmonella Typhi, its associated factors and antimicrobial susceptibility profile among patients attending Hawassa University Comprehensive Specialized Hospital, Hawassa, Ethiopia

IntroductionSalmonella Typhi infections cause significant morbidity and mortality worldwide, especially in developing countries including Ethiopia. This study aimed to determine the prevalence of Salmonella Typhi, its associated factors and antibiotic susceptibility profile among suspected typhoid patients.MethodsA cross-sectional study was conducted on 270 typhoid fever suspected patients at Hawassa University Comprehensive Specialized Hospital from June 2022 to September 2022. Data were collected using questionnaires by face-to-face interview. Stool samples for microbiological culture, blood samples for S. Typhi IgM/Entero-check WB rapid test and isolates for antimicrobial susceptibility tests were used through standard procedures and according to the reagents manufactures’ instructions. Hygiene implementation of patients was also assessed using interview. Sociodemographic and clinical characteristics of the patient’s were considered. Descriptive statistics were used to summarize the data, and logistic regression model analysis was performed to assess associations between S. Typhi infection and the associated sociodemographic and clinical factors.ResultsThe prevalence of S. Typhi IgM/Entero-check WB rapid test and stool culture results were 3.3%; (95% CI: 1.5–5.6) and 3.7%; (95% CI: 1.9–6.3) respectively. Not washing hands after latrine [AOR = 0.85, 95% CI (0.15–4.79), p = 0.05] is not significant but, not washing hands before meal [AOR = 0.053, 95% CI (0.08–0.36), p = 0.03], eating raw vegetables [AOR = 0.024, 95% CI (0.001–0.48), p = 0.015] and drinking water from a stream [AOR = 0.12, 95% CI (0.19–0.70), p = 0.001] were significantly associated with S. Typhi infection, but in terms of AOR, all are preventive. Susceptibility of isolates was 9/10 (90%), 8/10 (80%), and 8/10 (80%) to ciprofloxacin, ceftriaxone, and chloramphenicol, respectively. The majorities 100% and 80% of the isolates were resistant to ampicillin and cotrimoxazole, respectively. About 40% of the isolates were MDR.ConclusionThe prevalence of Salmonella Typhi with MDR has been observed. Therefore, health programmers and stakeholders should make efforts to improve the habit of sanitation, strengthen the capacity of laboratory diagnostic methods and increase awareness of the misprescription and misuse of antibiotics to reduce the impact of MDR bacteria.

Biofilm-mediated antibiotic tolerance in Staphylococcus aureus from spinal cord stimulation device-related infections.

Staphylococcus aureus is a predominant cause of infections in individuals with spinal cord stimulation (SCS) devices. Biofilm formation complicates these infections, commonly requiring both surgical and antibiotic treatments. This study explored the biofilm matrix composition and antimicrobial susceptibility of planktonic and biofilm-growing S. aureus isolates from individuals with SCS-related infections. Whole-genome sequencing (WGS) examined genotypes, virulome, resistome, and the pan-genome structure. The study also analyzed biofilm matrix composition, early surface adhesion, hemolytic activity, and antibiotic-susceptibility testing. WGS revealed genetic diversity among isolates. One isolate, though oxacillin susceptible, contained the mecA gene. The median number of virulence factor genes per isolate was 58. All isolates harbored the biofilm-related icaA/D genes. When assessing phenotypic characteristics, all strains demonstrated the ability to form biofilms in vitro. The antimicrobial susceptibility profile indicated that oxacillin, rifampin, and teicoplanin showed the highest efficacy against S. aureus biofilm. Conversely, high biofilm tolerance was observed for vancomycin, trimethoprim/sulfamethoxazole, and levofloxacin. These findings suggest that S. aureus isolates are highly virulent and produce robust biofilms. In cases of suspected biofilm infections caused by S. aureus, vancomycin should not be the primary choice due to its low activity against biofilm. Instead, oxacillin, rifampin, and teicoplanin appear to be more effective options to manage SCS infections.IMPORTANCESCS devices are increasingly used to manage chronic pain, but infections associated with these devices, particularly those caused by Staphylococcus aureus, present significant clinical challenges. These infections are often complicated by biofilm formation, which protects bacteria from immune responses and antibiotic treatments, making them difficult to eradicate. Understanding the genetic diversity, virulence, and biofilm characteristics of S. aureus isolates from SCS infections is critical to improving treatment strategies. Our study highlights the need to reconsider commonly used antibiotics like vancomycin, which shows reduced activity against biofilm-growing cells. Identifying more effective alternatives, such as oxacillin, rifampin, and teicoplanin, provides valuable insight for clinicians when managing biofilm-related S. aureus infections in patients with SCS implants. This research contributes to the growing evidence that biofilm formation is crucial in treating device-related infections, emphasizing the importance of tailoring antimicrobial strategies to the biofilm phenotype.

Characterisation of Neisseria gonorrhoeae strain differences in patients with multisite infection

BackgroundNeisseria gonorrhoeae, the aetiological agent of gonorrhoea, is an increasing global health priority due to high levels of antimicrobial resistance (AMR). It is estimated that up to 42% of patients...

Carriage and antimicrobial susceptibility of commensal Neisseria species from the human oropharynx

Commensal Neisseria (Nc) mainly occupy the oropharynx of humans and animals. These organisms do not typically cause disease; however, they can act as a reservoir for antimicrobial resistance genes that can be acquired by pathogenic Neisseria species. This study characterised the carriage and antimicrobial susceptibility profiles of Nc from the oropharynx of 50 participants. Carriage prevalence of Nc species was 86% with 66% of participants colonised with more than one isolate. Isolates were identified by MALDI-ToF and the most common species was N. subflava (61.4%). Minimum inhibitory concentrations (MICs) to penicillin, ceftriaxone, ciprofloxacin, azithromycin, tetracycline, and gentamicin were determined by agar dilution and E-test was used for cefixime. Using Ng CLSI/EUCAST guidelines, Nc resistance rates were above the WHO threshold of 5% resistance in circulating strains for changing the first line treatment empirical antimicrobial: 5% (CLSI) and 13 (EUCAST) for ceftriaxone and 29.3% for azithromycin. Whole genome sequencing of 30 Nc isolates was performed, which identified AMR genes to macrolides and tetracycline. Core gene MLST clustered Nc into three main groups. Gonococcal DNA uptake sequences were identified in two Nc clusters. This suggests that Nc have the potential AMR gene pool and transfer sequences that can result in resistance transfer to pathogenic Neisseria within the nasopharyngeal niche.

Occurrence and characterization of ESKAPE organisms on the hands of veterinary students before patient contact at a veterinary academic hospital, South Africa

ObjectiveThis study aimed to investigate the presence of ESKAPE organisms on the hands of students working in the intensive care unit (ICU) at a veterinary academic hospital.MethodsA cross-sectional study was conducted among students working in an ICU at a veterinary academic hospital in South Africa. Students were sampled before the start of the ICU shift using a modified glove-juice method. Standard microbiological techniques and a series of polymerase chain reaction (PCR) assays were used to identify and characterize the bacteria. All the isolates were tested for resistance against a specific panel of antibiotics using the disk diffusion method. Proportions of bacterial species and their antimicrobial-susceptibility profiles were calculated.ResultsAt screening, all the veterinary students (n = 62) carried at least one of the ESKAPE organisms on their hands. Escherichia coli was the most isolated organism (76%, 47/62), followed by P. aeruginosa (48%, 30/62), A. baumannii (47%, 29/62), E. faecium (35%, 22/62), K. pneumoniae (27%, 17/62), and S. aureus (24%, 15/62). A reduced proportion of isolates were recovered from the samples, E. coli (26%, 12/47), E. faecium (23%, 5/22), P. aeruginosa (43%, 13/30), A. baumannii (24%,7/29), K. pneumoniae (41%, 7/17), and S. aureus (20%, 3/15). Most of the organisms showed a high proportion of resistance to at least one antibiotic. Multidrug resistance was reported among just over half (56%, 5/9) of E. coli, 40% (2/5) of E. faecium, 100% (13/13) of P. aeruginosa, and 33% (1/3) of S. aureus isolates.ConclusionStudents working in the ICU carry several organisms belonging to the ESKAPE group of organisms before contact with patients. Moreover, MDR resistance was common among this group of organisms. The findings of the present study underscore the importance of infection prevention and control (IPC) strategies to help reduce the likelihood of the spread of these organisms to personnel, owners, family members, and patients.

Case Series: Emerging Pathogens Aerococcus urinae and Aerococcus sanguinicola at a Canadian tertiary care hospital

Abstract Introduction/Objective Background: Aerococcus urinae and sanguinicola are emerging opportunistic pathogen linked with urinary tract infections. Unmanaged Aerococcus infections have the propensity to precipitated into urosepsis. The ongoing gestalt of managing these infections needs standardization. We reviewed A. urinae and sanguinicola isolates from our clinical microbiology laboratory to better characterize its spectrum of clinical presentation, sources of infection, microbiological characteristics, and antimicrobial management. Methods/Case Report Methods: The electronic microbiology database was utilized to review the retrospective clinical data of patients that grew positive cultures for Aerococcus urinae and sanguinicola on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) in Saskatchewan from January to July 2023. Demographic variables, site of presentation, microbiological parameters surrounding culture and sensitivities, and antimicrobial management were recorded. The results were analyzed on SPSS 28 software. Results (if a Case Study enter NA) Results: This cohort (n=115) had a median age 82 years [Range: 7 to 103] with a female predilection (F:M = 78:37). A. urinae and sanguinicola were primarily involved in UTI (n=96), obstructive uropathy (n=9), and urosepsis (n=6). The hypothyroidism (26.9%, n = 31) rate in this population was 3-fold higher than the age-matched background rate for our province. Aerococcus infections were predominantly monomicrobial (73.9%, n= 85 out of 115) and showed sensitivity for ceftriaxone, penicillin G, and vancomycin. Antimicrobials were seldom used in the UTI cohort (31.2%, n=30 out of 96). Amoxicillin-clavulanate (29.8%, n=25 out 84) was the most popular choice at patient discharge in monomicrobial Aerococcus infections only. Conclusion Conclusion: Aerococcus urinae and sanguinicola are emerging uropathogen. Despite this, the clinical significance of these Aerococcus species remains undervalued. Our case series shows that untreated or recurrent A. urinae and A. sanguinicola infections can precipitate into urosepsis. Clinicians should utilize the antimicrobial susceptibility profiles for these Aerococcus species to provide appropriate antimicrobial coverage and manage these pathogens effectively. Further studies should explore the link between hypothyroidism and these aerococcal infections.

Sentinel Surveillance reveals phylogenetic diversity and detection of linear plasmids harboring vanA and optrA among enterococci collected in the United States.

Enterococcus faecalis and Enterococcus faecium are frequent causes of healthcare-associated infections. Antimicrobial-resistant enterococci pose a serious public health threat, particularly vancomycin-resistant enterococci (VRE), for which treatment options are limited. The Centers for Disease Control and Prevention's Division of Healthcare Quality Promotion Sentinel Surveillance system conducted surveillance from 2018 to 2019 to evaluate antimicrobial susceptibility profiles and molecular epidemiology of 205 E. faecalis and 180 E. faecium clinical isolates collected from nine geographically diverse sites in the United States. Whole genome sequencing revealed diverse genetic lineages, with no single sequence type accounting for more than 15% of E. faecalis or E. faecium. Phylogenetic analysis distinguished E. faecium from 19 E. lactis (previously known as E. faecium clade B). Resistance to vancomycin was 78.3% among E. faecium, 7.8% among E. faecalis, and did not occur among E. lactis isolates. Resistance to daptomycin and linezolid was rare: E. faecium (5.6%, 0.6%, respectively), E. faecalis (2%, 2%), and E. lactis (5.3%, 0%). All VRE harbored the vanA gene. Three of the seven isolates that were not susceptible to linezolid harbored optrA, one chromosomally located and two on linear plasmids that shared a conserved backbone with other multidrug-resistant conjugative linear plasmids. One of these isolates contained optrA and vanA co-localized on the linear plasmid. By screening all enterococci, 20% of E. faecium were predicted to harbor linear plasmids, whereas none were predicted among E. faecalis or E. lactis. Continued surveillance is needed to assess the future emergence and spread of antimicrobial resistance by linear plasmids and other mechanisms.IMPORTANCEThis work confirms prior reports of E. faecium showing higher levels of resistance to more antibiotics than E. faecalis and identifies that diverse sequence types are contributing to enterococcal infections in the United States. All VRE harbored the vanA gene. We present the first report of the linezolid resistance gene optrA on linear plasmids in the United States, one of which co-carried a vanA cassette. Additional studies integrating epidemiological, antimicrobial susceptibility, and genomic methods to characterize mechanisms of resistance, including the role of linear plasmids, will be critical to understanding the changing landscape of enterococci in the United States.

Prevalence, Species Distribution and Resistance of Candidemia in Pediatric and Adult Patients in a Northeast Italy University Hospital.

Candidemia and invasive candidiasis (IC) are causes of morbidity and mortality in healthcare settings, with notable differences between children and adults. Understanding the species distribution and antimicrobial susceptibility profiles of clinical isolates can guide empiric therapy in patients at risk of IC. This study investigated the incidence and antifungal susceptibility patterns of yeasts involved in IC in pediatric and adult patients from 2019 to 2023. The average incidence of IC was 0.715 per 1000 patients, increasing over the study period; infants had the highest incidence rates. Over half of the IC episodes occurred in intensive care units (ICUs). Non-albicans Candida (NAC) species represented the most frequently isolated species in adults and children (55.96% and 50.0%, respectively), with the prevalence of C. parapsilosis (26.45% and 14.7%, respectively), N. glabratus (14.97% and 8.82%, respectively) and C. tropicalis (4.36% and 2.94%, respectively). C. lusitaniae was identified in 14.7% of pediatric IC cases. In NAC species, antifungal resistance has also increased over the five years of the study: 69.12% were resistant to azoles and 7.35% were resistant to micafungin. Resistance was higher in pediatric patients. Our study highlights differences in IC characteristics between pediatric and adult populations and emphasizes the importance of targeted antifungal stewardship in ICU patients with NAC invasive infections.

Genotypic and phenotypic characterization of the first Latin America isolates of Corynebacterium rouxii, a recently described member of the Corynebacterium diphtheriae complex reported in Europe.

The genus Corynebacterium is the largest genera among corynebacteria and has a range of species widely spread in ecological niches, some with epidemic potential and capable of causing fatal diseases. In recent years, due to the reclassifications and discoveries of new potentially toxin-producing species, microbiological identification and epidemiological control have been compromised, becoming possible only with sequencing techniques. Two bacterial strains isolated from a cat were identified by MALDI-TOF mass spectrometry as Corynebacterium diphtheriae and sent to the collaborating center of the Brazilian Ministry of Health for molecular identification and determination of toxigenicity potential, which were initially performed by multiplex PCR method. In addition, the antimicrobial susceptibility profile was determined according to BrCAST. Finally, for the final identification at the species level and effective epidemiological monitoring, the sequencing of the 16S rRNA and rpoB housekeeping genes was carried out. The isolates were identified as nontoxigenic C. diphtheriae strains by mPCR. Both strains were found susceptible to all antimicrobial agents. Although the identification at the species level was not possible through similarity analysis of S rRNA and rpoB housekeeping genes, the phylogenetic analysis showed that the isolates belonged to the species Corynebacterium rouxii with a high value of reliability. This is the first report of the isolation of C. rouxii in Latin America. Molecular identification, whether by the MALDI-TOF mass spectrometry or PCR techniques, does not discriminate C. rouxii from C. diphtheriae, requiring gene sequencing and phylogenetic analysis for correct identification at the species level.

A-290 Prevalence and Antimicrobial Resistance Pattern of Microorganisms Recovered From Bloodstream Infections From Public Hospitals of São Paulo City, Brazil

Abstract Background Nosocomial Bloodstream Infections (nBSI) are an important cause of morbidity and mortality. Brazilian studies concerning bloodstream infections are important tools that can bring specific issues related to antimicrobial resistance. The objective of this study was to describe the frequency and antimicrobial susceptibility profile of bacterial isolates from BSI in patients admitted to public hospitals in 2022 and 2023. Methods This study was a retrospective analysis from 12 hospitals (January 2022 to December 2023) based on BSI isolates laboratory data detected by the clinical microbiology department of a medical diagnostic laboratory. The identification and susceptibility tests were performed using MALDI-TOF mass spectrometry (Vitek MS) and Vitek®2 systems, according to the manufacture’s recommendations. Coagulase Negative Staphylococci (CoNS) BSI was only considered in the presence of at least two sets of positive blood cultures with the same organism. Results During the period (January 2022 to December 2023) a total of 19,588 microorganisms isolated from BSI were obtained from 12 hospitals. The frequency of organism group was Gram-positive (10,707; 54.7%), Gram-negative (7,874; 40.2%), yeasts (961; 4.9%) and filamentous (46; 0.2%). The order of prevalence (top ten) organisms was CoNS (5,149; 26.3%); Staphylococcus aureus (2,769; 14.1%); Klebsiella spp. (2,355; 12.0%); Escherichia coli (1,301; 6.6%); Acinetobacter spp. (1,293; 6.6%); Streptococcus spp. (1,125; 5.7%); Enterococcus spp. (1,112; 5.7%); Candida spp. (937; 4.8%); Pseudomonas spp. (749; 3.8%) and Proteus spp. (553; 2.8%). Extended spectrum beta-lactamase rates for E. coli and Klebsiella pneumoniae were 31.6% (268/848) and 74.9% (1027/1371), respectively. The resistance to carbapenems was detected mainly in 74.1% (661/892) of Acinetobacter spp. isolates, 60.7% (832/1371) of Klebsiella pneumoniae; 24.5% (114/465) of P. aeruginosa; 9.7% (34/349) of Proteus spp. and 1.4% (12/828) of Escherichia coli. Antimicrobial resistance was observed mainly in 87.2% of CoNS (2831/3247) and 44.5% of S. aureus (743/1669) to methicillin; 22.9% (146/637) of Enterococccus spp. to vancomycin. Conclusions The frequency of Klebsiella spp. isolates from nBSI has progressively increased and effective infection control measures should be taken to prevent them from spreading. The rates of antimicrobials resistance reported for Klebsiella pneumoniae, Acinetobacter spp., CoNS, S. aureus and Enterococcus spp. reinforce the high resistance rates to antimicrobials in São Paulo city.

A-254 Increase of Stenotrophomonas maltophilia Isolates Non-Susceptible to Trimethoprim-Sulfamethoxazole and/or Levofloxacin at Brazilian Hospitals

Abstract Background Stenotrophomonas maltophilia is an emerging multidrug-resistant pathogen that exhibits intrinsic and acquired resistance to a wide variety of antimicrobial agents such as β-lactams, aminoglycosides, quinolone, tetracyclines and disinfectants. In addition to that, the increased resistance to sulfamethoxazole/trimethoprim (SMX/TMP) and Levofloxacin has been reported in the past few years, leading to few therapeutic options. This study aimed to describe the increase of Stenotrophomonas maltophilia clinical isolates recovered from Brazilian hospitals over a 6-year analysis (January 2018 to December 2023). Methods This study design was a retrospective, observational analysis based on microbiological data of emergent BGN-NF isolates detected in several Brazilian tertiary hospitals. The bacterial identification was performed by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF/MS) and the antimicrobial susceptibility profile to trimethoprim-sulfamethoxazole and levofloxacin was determined using disk-diffusion method and epsilometer method, respectively. Only one sample per patient was considered in this analysis. Results During the 6 year period, a total of 1,706 (2018; 221), (2019; 203), (2020; 294), (2021; 276), (2022; 294) and (2023; 418) Stenotrophomonas maltophilia strains were isolated from blood (n=626), respiratory tract (n=365), fluid and secretion (n=235), skin and soft tissue (n=162), urine (n=132), catheter tip (n=112), swab (n=36), bone fragment (n=29) and cerebrospinal fluid (n=9). The major frequency of S. maltophilia isolation occurred among man (52.6%) and the main age range was over 60 years (42.7%), while 0-10 comprised 16.6% of cases. Compared the 6-years period, the resistance rate to trimethoprim-sulfamethoxazole was 2.7%; 5.4%; 5.8%; 2.2%; 5.8%; 7.9% and levofloxacin was 3.6%; 3.4%; 3.1%; 3.3%; 1.7%; 2.9%, respectively. The resistance rate to trimethoprim-sulfamethoxazole and levofloxacin, simultaneously, was 0.23%. Conclusions The incidence rate of S. maltophilia infections has increased significantly, especially in the last year, followed by an increase in the pattern of resistance to trimethoprim-sulfamethoxazole. Regarding trimethoprim-sulfamethoxazole and levofloxacin co-resistance, very low rates were detected in our analysis. Our data point to a scenario wherein the presence of S. maltophilia may have been intensified by the covid-19 pandemic. Regional surveillance reports are extremely important and should be out to understand some aspects of the dynamics of bacterial resistance in both hospital and community settings.

Antimicrobial susceptibility profiles among commensal Mannheimia haemolytica and Pasteurella multocida isolated from apparently healthy sheep processed in California: Results from a cross-sectional pilot study

Antimicrobial resistance (AMR) is a growing challenge for the successful treatment of bacterial infections in both human and veterinary medicine. Despite the need to mitigate AMR, food-producing animal species lack adequate information on bacterial susceptibility to support antimicrobial stewardship for conditions that drive antimicrobial usage, such as ovine respiratory disease (ORD). In an effort to help address this gap, the upper respiratory tract (URT) from 620 apparently healthy sheep carcasses was sampled at slaughter in California (CA), from April through September 2021, to determine the antimicrobial susceptibility profiles of commensal Mannheimia haemolytica and Pasteurella multocida, two bacteria commonly associated with ORD. Sheep sampled in the study were selected based on origin prior to processing (out-of-state or CA) and marketing status (antibiotic-free or conventional management), two factors hypothesized to influence antimicrobial susceptibility profiles. Of the total 620 carcasses sampled, 343 had at least one isolate of M. haemolytica or P. multocida recovered, for a recovery rate of 55.3%. The recovery rate among sampled carcasses was 46.8% (290/620) for M. haemolytica and 15.8% (98/620) for P. multocida. Utilizing Clinical and Laboratory Standards Institute (CLSI) clinical breakpoints as interpretive criteria, all 98P. multocida isolates were pansusceptible to the antimicrobials tested that are labeled for use in sheep, with the exception of one isolate that classified as intermediate to tilmicosin. Of the 290M. haemolytica isolates, the greatest resistance was found to penicillin, with 51.0% (148) of isolates classified as intermediate and 25.2% (73) resistant, while nine isolates were resistant to chlortetracycline and oxytetracycline and one isolate was intermediate to spectinomycin. Multidrug resistance (resistance to three or more antimicrobial classes) was not found in any isolate of either target organism. Very low to no AMR was observed across both bacterial species tested, demonstrating that M. haemolytica and P. multocida in this apparently healthy sheep population remain broadly susceptible to the antimicrobials licensed for the treatment of ORD. In addition, antimicrobial susceptibility did not differ based on origin or marketing status, as defined for this study. Sampling at slaughter provides an opportunity to collect baseline information about antimicrobial susceptibility of the commensal flora of the sheep URT that can give rise to ORD, but may not be generalizable to sheep with clinical respiratory disease or to sheep reared by non-commercial producers.

Antimicrobial susceptibility profiles of invasive bacterial infections among children from low- and middle-income countries in the Western Pacific Region (WPRO) – a systematic review and meta-analysis

Antimicrobial resistance increasingly impacts paediatric mortality, particularly in resource-constrained settings. We aimed to evaluate the susceptibility profiles of bacteria causing infections in children from the Western Pacific region. We conducted a systematic review and meta-analysis of bacteria responsible for common infections in children. We included studies published from January 2011 to December 2023 (PROSPERO CRD42021248722). Pooled susceptibilities were evaluated against empiric antibiotics recommended to treat common clinical syndromes. Fifty-one papers met inclusion criteria, incorporating 18,330 bacterial isolates. Of available published data, only six countries from the region were represented. Escherichia coli revealed a pooled susceptibility to ampicillin of 17% (95% CI 12-23%, n=3292), gentamicin 63% (95% CI 59-67%, n=3956), and third-generation cephalosporins 59% (95% CI 49-69%, n=3585). Susceptibility of Klebsiella spp. to gentamicin was 71% (95% CI 61-80%, n=2323), third-generation cephalosporins 35% (95% CI 22-49%, n=2076), and carbapenems 89% (95% CI 78-97%, n=2080). Pooled susceptibility of Staphylococcus aureus to flucloxacillin was 72% (95% CI 58-83%, n=1666), and susceptibility of Streptococcus pneumoniae meningitis isolates to ampicillin was 26% (95% CI 11-44%, n=375), and 63% (95% CI 40-84%, n=246) to third-generation cephalosporins. The burden of antimicrobial resistance among bacteria responsible for common infections in children across the Western Pacific region is significant, and the currently recommended World Health Organization antibiotics to treat these infections may be inefficacious. Strategies to improve the availability of high-quality data to understand the burden of antimicrobial resistance in the region are necessary. The study was supported by an Australian GovernmentNational Health and Medical Research Council Investigator Grant. This research was funded in part by the Wellcome Trust [220211/Z/20/Z]. For the purpose of Open Access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission.

Distribution and Antimicrobial Susceptibility Profile of Extended Spectrum Beta-Lactamase Producing-Escherichia coli from Ruminants in Maiduguri, Nigeria: Public Health Implications

Extended spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli) is resistant to many antibiotics, including cephalosporins and penicillin. The emergence of ESBL-E. coli poses a threat to the entire animal and human community, not just individuals with direct exposure to ruminants but also to the environment. The study evaluated the isolation rate and antimicrobial susceptibility profile of ESBL-producing E. coli from 128 ruminants in the University of Maiduguri campus. E. coli was isolated from 32 (25%) of the rectal swabs collected from cattle, goats, and sheep. ESBL-producing E. coli was more common in young animals 8(30.8%) than in adult animals 12 (11.8%). More than 80% of the isolates were resistant to all of the beta-lactam antibiotics used in the study. The study suggests that the high prevalence of ESBL-producing E. coli in ruminants may be associated with the unregulated use of beta-lactam antibiotics in veterinary practice and animal husbandry. We recommend public health awareness about the dangers of antimicrobial resistance. Also, continued monitoring of BL-E. coli prevalence in both animals and humans is crucial to track trends and guide interventions. Promoting the judicious use of antibiotics in both human and veterinary medicine is essential to reduce selective pressure for resistance development. Improved hygiene practices at farms, slaughterhouses, and food processing facilities can minimize contamination and human exposure.