Phenotypic and molecular characterization of β-lactamase-producing Klebsiella species among children discharged from hospital in Western Kenya

BACKGROUND

The emergence and spread of β-lactamase-producing Klebsiella spp. has been associated with a substantial healthcare burden resulting in therapeutic failures. We sought to describe the proportion of phenotypic resistance to commonly used antibiotics, characterize β-lactamase genes among isolates with antimicrobial resistance (AMR), and assess the correlates of phenotypic AMR in Klebsiella spp. isolated from stool or rectal swab samples collected from children being discharged from hospital.

METHODS

We conducted a cross-sectional study involving 245 children aged 1-59 months who were being discharged from hospitals in western Kenya between June 2016 and November 2019. Whole stool or rectal swab samples were collected and Klebsiella spp. isolated by standard microbiological culture. β-lactamase genes were detected by PCR whilst phenotypic antimicrobial susceptibility was determined using the disc diffusion technique following standard microbiology protocols. Descriptive analyses were used to characterize phenotypic AMR and carriage of β-lactamase-producing genes. The modified Poisson regression models were used to assess correlates of phenotypic beta-lactam resistance.

RESULTS

The prevalence of β-lactamase carriage among Klebsiella spp. isolates at hospital discharge was 62.9% (154/245). Antibiotic use during hospitalization (adjusted prevalence ratio [aPR] = 4.51; 95%CI: 1.79-11.4, p < 0.001), longer duration of hospitalization (aPR = 1.42; 95%CI: 1.14-1.77, p < 0.002), and access to treated water (aPR = 1.38; 95%CI: 1.12-1.71, p < 0.003), were significant predictors of phenotypically determined β-lactamase. All the 154 β-lactamase-producing Klebsiella spp. isolates had at least one genetic marker of β-lactam/third-generation cephalosporin resistance. The most prevalent genes were blaCTX-M 142/154 (92.2%,) and blaSHV 142/154 (92.2%,) followed by blaTEM 88/154 (57.1%,) and blaOXA 48/154 (31.2%,) respectively.

CONCLUSION

Carriage of β-lactamase producing Klebsiella spp. in stool is common among children discharged from hospital in western Kenya and is associated with longer duration of hospitalization, antibiotic use, and access to treated water. The findings emphasize the need for continued monitoring of antimicrobial susceptibility patterns to inform the development and implementation of appropriate treatment guidelines. In addition, we recommend measures beyond antimicrobial stewardship and infection control within hospitals, improved sanitation, and access to safe drinking water to mitigate the spread of β-lactamase-producing Klebsiella pathogens in these and similar settings.

Streamlined fabrication of AuPtRh trimetallic nanoparticles supported on Ti3C2MXene for enhanced photocatalytic activity in cephalosporins degradation

The escalating prevalence of cephalosporin antibiotics in wastewater poses a serious threat to public health and environmental balance. Thus, it is crucial to develop effective methods for removing cephalosporin antibiotics from water sources. Herein, we propose the use of AuPtRh trimetallic nanoparticles supported on Ti3C2MXene as a photocatalyst for the degradation of cephalosporin antibiotics. Initially, AuPtRh nanoparticles were uniformly grown onto Ti3C2MXene sheets using one-step reduction technique. The prepared AuPtRh/Ti3C2MXene exhibited a complete degradation of cefixime and ceftriaxone sodium, while an impressive degradation efficiency of 91.58 % for cephalexin was achieved after 60 min of exposure to visible light, surpassing the performance of its individual AuPtRh nanoparticles and Ti3C2MXene. The enhanced photoactivity of AuPtRh/Ti3C2MXene was resulted from improved light absorption capacity and efficient generation, separation, and transfer of charge carriers driven by the formation of heterojunction between AuPtRh and Ti3C2MXene. Electron paramagnetic resonance and radicals trapping experiments results revealed that •O2- and h+ are the principal reactive species governing the degradation of cephalosporins. The photocatalyst exhibited excellent stability and could be reused four times without significant loss in efficiency. Our study highlights the potential of MXene composites for environmental remediation, offering insights into designing sustainable AuPtRh/Ti3C2MXene photocatalyst for water pollutant degradation.

Comparative efficacy and optimal duration of first-line antibiotic regimens for acute otitis media in children and adolescents: a systematic review and network meta-analysis of 89 randomized clinical trials

INTRODUCTION

Antibiotic use for acute otitis media (AOM) is one of the major sources of antimicrobial resistance. However, the effective minimal antibiotic duration for AOM remains unclear. Moreover, guidelines often recommend broad ranges (5-10 days) of antibiotic use, yet the clinical impact of such a wide window has not been assessed.

METHODS

We systematically searched PubMed/MEDLINE, Embase, Scopus, Web of Science, and Cochrane Library from database inception to 6 October 2021. Network meta-analysis was conducted on randomized controlled trials that assessed antibiotic treatment for AOM in children (PROSPERO CRD42020196107).

RESULTS

For amoxicillin and amoxicillin-clavulanate, 7-day regimens were noninferior to 10-day regimens in clinical responses [amoxicillin: risk ratio (RR) 0.919 (95% CI 0.820-1.031), amoxicillin-clavulanate: RR 1.108 (0.957-1.282)], except for ≤ 2 years. For the third-generation cephalosporins, 7-day and 10-day regimens had similar clinical responses compared to placebo [7-day: RR 1.420 (1.190-1.694), 10-day: RR 1.238 (1.125-1.362) compared to placebo]. However, 5-day regimens of amoxicillin-clavulanate and third-generation cephalosporins were inferior to 10-day regimens. Compared to amoxicillin, a shorter treatment duration was tolerable with amoxicillin-clavulanate.

CONCLUSIONS

Our findings indicated that 10 days of antibiotic use may be unnecessarily long, while the treatment duration should be longer than 5 days. Otherwise, 5-day regimens would be sufficient for a modest treatment goal. Our findings revealed that the current wide range of recommended antibiotic durations may have influenced the clinical outcome of AOM, and a narrower antibiotic duration window should be re-established.

Prolonged versus intermittent β-lactam infusion in sepsis: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The two latest studies on prolonged versus intermittent use of β-lactam antibiotics in patients with sepsis did not reach consistent conclusions, further contributing to the controversy surrounding the effectiveness of the prolonged β-lactam antibiotics infusion strategy. We conducted a systemic review and meta-analysis to evaluate the efficacy and safety of prolonged and intermittent β-lactam infusion in adult patients with sepsis.

METHODS

We systematically searched PubMed, EMBASE, and Cochrane Library databases for original randomized controlled trials comparing prolonged and intermittent β-lactam infusion in sepsis patients. A random-effects model was used to evaluate mortality, clinical success, microbiological success, and adverse events. We also conducted subgroup analyses to explore the impact of various factors on the mortality rates. Relative risk (RR) and corresponding 95% confidence intervals (CIs) were used to calculate the overall effect sizes for dichotomous outcomes. This meta-analysis was registered in PROSPERO (CRD42023463905).

RESULTS

We assessed 15 studies involving 2130 patients. In our comprehensive assessment, we found a significant reduction in all-cause mortality (RR, 0.83; 95% CI 0.72-0.97; P = 0.02) and a notable improvement in clinical success (RR, 1.16; 95% CI 1.03-1.31; P = 0.02) in the prolonged infusion group compared to the intermittent infusion group, whereas microbiological success did not yield statistically significant results (RR, 1.10; 95% CI 0.98-1.23; P = 0.11). No significant differences in adverse events were observed between the two groups (RR, 0.91; 95% CI 0.64-1.29; P = 0.60). Additionally, remarkable conclusions were drawn from subgroup analyses including studies with sample sizes exceeding 20 individuals per group (RR, 0.84; 95%CI 0.72-0.98; P = 0.03), research conducted post-2010 (RR, 0.84; 95%CI 0.72-0.98; P = 0.03), cases involving infections predominantly caused by Gram-negative bacteria (RR, 0.81; 95%CI 0.68-0.96; P = 0.02), as well as the administration of a loading dose (RR, 0.84; 95% CI 0.72-0.97; P = 0.02) and the use of penicillin (RR, 0.61; 95% CI 0.38-0.98; P = 0.04).

CONCLUSIONS

Compared to intermittent infusion, prolonged infusion of β-lactam antibiotics significantly decreases all-cause mortality among patients with sepsis and enhances clinical success without increasing adverse events.

Exploring fluorescence of metal nanoparticles for effective utility in drug sensing: A Promising ''on-off'' fluorescence probe for analysis of cephalosporins is fabricated

A promising fluorescent nano sensor was fabricated exploiting the unique optical and physicochemical properties of silver nanoparticles (AgNPs). AgNPs were prepared following a chemical reduction technique to get a highly water-soluble nano sensor, stable for at least 1 month without the need of organic stabilizers. Full characterization of AgNPs was done using different spectroscopic and microscopic techniques. They exhibit excellent water solubility, physicochemical and optical properties, enabling them to be successfully applied in chemical sensing of drugs. The prepared AgNPs could be conceived as a fluorescent probe for the fluorimetric determination of two commonly administered cephalosporins ceftriaxone (CTX) and cefepime (CFP) based on the quenching behavior of the fluorescence omitting the need for pre-derivatization or chromogenic reagents. The fluorescence intensity of AgNPs at 485 nm after excitation at 242 nm was quantitively quenched upon increasingly adding the studied drugs over the concentration ranges of 1-10 µg/mL and 0.9-9 µg/mL with detection limits of 0.178 µg/mL and 0.145 µg/mL for CTX and CFP, respectively. The quenching mechanisms were investigated and illustrated. The influence of different experimental parameters was studied and optimized. The suggested sensor provides an innovative, sensitive, and eco-friendly approach for the assay of the drugs in their pharmaceutical vials and quality control laboratories with excellent % recoveries of 99.88 ± 1.15, 99.95 ± 1.15 for CTX and CFP, respectively. The method was validated in accordance with ICH Q2 R1 recommendations. The greenness evaluation was performed through both Eco-Scale and GAPI revealing the green criteria of the developed method.

Efficient green silver nanoparticles-antibiotic combinations against antibiotic-resistant bacteria

Antibiotic-resistant bacterial strains and the consequent surge in infections caused by them have become major public health concerns. Silver nanoparticles (AgNPs) exhibit antibacterial properties and have wide applications in biomedical sciences. In this study, AgNPs were synthesized in the presence of antibiotics: Ceftazidime (Cft), Cefotaxime (Cef), Ceftriaxone (Cfx), and Cefepime (Cpm), along with the extract of Mentha longifolia. Mentha longifolia-based AgNPs were kept as the control for all experiments. The associated metabolites, structural properties, surface charges, and antibacterial activity of the AgNPs were also evaluated. Overall, a blue-shift of SPR peaks was observed for control AgNPs (λmax = 421 nm, 422 nm, 426 nm, and 406 nm for Cft-AgNPs, Cef-AgNPs, Cfx-AgNPs, and Cpm-AgNPs, respectively), compared to the control (λmax = 438 nm). Fourier-transform infrared spectroscopy showed that antibiotic-based AgNPs had distinct peaks that corresponded to the respective antibiotics, which were not observed in the control. XRD analysis showed that there were observed changes in crystallinity in antibiotic-based AgNPs compared to the control. TEM images revealed that all samples had spherical nanoparticles with different sizes and distributions compared to the control. The Zeta potential for extract-based AgNPs was - 33.6 mV, compared to -19.6 mV for Cft-AgNPs, -2 mV for Cef-AgNPs, -21.1 mV for Cfx-AgNPs, and - 24.2 mV for Cpm-AgNPs. The increase in the PDI value for antibiotic-based AgNPs also showed a highly polydisperse distribution. However, the antibiotic-AgNPs conjugates showed significantly higher activity against pathogenic bacteria. The addition of antibiotics to AgNPs brought significant changes in structural properties and antibacterial activities.

QSAR analysis of five generations of cephalosporins to establish the structural basis of activity against methicillin-resistant and methicillin-sensitive Staphylococcus aureus

Solving the worldwide problem of growing bacterial drug resistance will require a short-run and medium-term strategy. Structure-activity relationship (SAR) and quantitative SAR (QSAR) analyses have recently been utilized to reveal the molecular basis of the antibacterial activity and antibacterial spectrum of penicillins, the use of which is no longer solely empirical. Likewise, a more rational drug design can be achieved with cephalosporins, the largest group of β-lactam antibiotics. The current contribution aimed to establish the molecular and physicochemical basis of the antibacterial activity of five generations of cephalosporins on methicillin-sensitive (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). With SAR and QSAR analyses, the molecular portions that provide essential and additional antibacterial activity were identified. The substitutions with greater volume and polarity on the R2 side chain of the cephem nucleus increase potency on MSSA. The best effect is produced by substitutions with polar nitrogen atoms at the alpha-carbon (Cα). Substitutions with greater volume and polarity on the R1 side chain further enhance antibacterial activity. In contrast, the effect against MRSA seems to be independent of any substitution on R2 or at the Cα, while depending on the accessory portions with greater volume and polarity on R1.

Analysis of a clinical guideline for treatment and early discharge in complicated acute appendicitis

OBJECTIVE

The objective of this study was to assess the results of a clinical guideline for the treatment and early discharge of patients with complicated acute appendicitis in terms of infectious complications and hospital stay.

MATERIALS AND METHODS

A guideline for appendicitis treatment according to severity was created. Complicated appendicitis cases were treated with ceftriaxone-metronidazole for 48h, with discharge being approved if certain clinical and blood test criteria were met. A retrospective analytical study comparing the incidence of postoperative intra-abdominal abscess (IAA) and surgical site infection (SSI) in patients under 14 years of age to whom the new guideline was applied (Group A) vs. the historical cohort (Group B, treated with gentamicin-metronidazole for 5 days) was carried out. A prospective cohort study to assess which antibiotic therapy (amoxicillin-clavulanic acid or cefuroxime-metronidazole) proved more effective in patients meeting early discharge criteria was also conducted.

RESULTS

205 patients under 14 years of age were included in Group A, whereas 109 patients were included in Group B. IAA was present in 14.3% of patients from Group A vs. 13.8% from Group B (p= 0.83), while SSI was present in 1.9% of patients from Group A vs. 8.25% from Group B (p= 0.008). Early discharge criteria were met by 62.7% of patients from Group A. Median hospital stay decreased from 6 to 3 days. At discharge, 57% of patients received amoxicillin-clavulanic acid, whereas 43% received cefuroxime-metronidazole, with no differences being found in terms of SSI (p= 0.24) or IAA (p= 0.12).

CONCLUSIONS

Early discharge reduces hospital stay without increasing the risk of postoperative infectious complications. Amoxicillin-clavulanic acid is a safe option for at-home oral antibiotic therapy.

[New antibiotics for the treatment of urinary tract infections]

Urinary tract infections (UTIs) are among the most common bacterial infections. The clinical phenotypes of UTIs are heterogeneous, ranging from rather benign uncomplicated infections to complicated UTIs and pyelonephritis to severe urosepsis. Antibiotics have become indispensable in modern medicine, but the development of resistance is threatening clinical effectiveness. Antimicrobial resistance rates are locally high in UTIs, however can vary significantly depending on the population studied and the type of study. In addition, between 1990 and 2010, there was a discovery void in the development of new antibiotics that is still having an impact today. In recent years, UTIs have emerged as an infection model for research into novel antibiotics. In the last 10 years, novel gram-negative active drugs have been explored in these groups. On the one hand, novel beta-lactam/beta-lactamase inhibitor combinations were investigated, and there has also been further development of cephalosporins and aminoglycosides.

Effect of non-cephalosporin antibiotic prophylaxis on the risk of periprosthetic joint infection after total joint replacement surgery: a retrospective study with a 1-year follow-up

Background

Cephalosporins are recommended as first-line antibiotic prophylaxis in total joint replacement surgery. Studies have shown an increased risk for periprosthetic joint infection (PJI) when non-cephalosporin antibiotics have been used. This study examines the effect of non-cephalosporin antibiotic prophylaxis on the risk for PJI.

Methods

Patients with a primary hip or knee replacement performed from 2012 to 2020 were identified (27 220 joint replacements). The primary outcome was the occurrence of a PJI in a one-year follow-up. The association between perioperative antibiotic prophylaxis and the outcome was examined using logistic regression analysis.

Discussion

Cefuroxime was used as prophylaxis in 26,467 operations (97.2%), clindamycin in 654 (2.4%) and vancomycin in 72 (0.3%). The incidence of PJI was 0.86% (228/26,467) with cefuroxime and 0.80% (6/753) with other prophylactic antibiotics. There was no difference in the risk for PJI with different prophylactic antibiotics in the univariate (OR 1.06, 95% CI 0.47-2.39) or multivariable analysis (OR 1.02, 95% CI 0.45-2.30).

Conclusion

Non-cephalosporin antibiotic prophylaxis in primary total joint replacement surgery was not associated with an increased risk for PJI.

Risk factors for recurrent healthcare-facility associated Clostridioides difficile infection in a Swedish setting

PURPOSE

The objectives were to determine the risk factors for recurrent healthcare facility-associated Clostridioides difficile infection (HCF-CDI) in a high CDI incidence, low antibiotic use setting and to determine if length of cefotaxime exposure is a risk factor for recurrent HCF-CDI.

METHODS

The risk factors for recurrent HCF-CDI were evaluated with a retrospective nested case control study based on chart reading. The risk factors were evaluated univariately and multivariately. Length of risk antibiotic exposure was evaluated further in a subanalysis.

RESULTS

Risk factors for recurrent HCF-CDI were renal insufficiency (25.4% of cases compared to 15.4% of controls p = 0.006) and metronidazole treatment of initial CDI episode (88.4% compared to 71.7% p = 0.01). Exposure to cefotaxime and risk for recurrent CDI showed a dose-dependent relationship (linear by linear p = 0.028).

CONCLUSIONS

Renal insufficiency and metronidazole treatment were independent risk factors for recurrent HCF-CDI in our setting. The relationship between cefotaxime exposure and risk for recurrent HCF-CDI, dose-dependent, could be evaluated further in a setting with high cefotaxime use.

Streptococcus cristatus bacteremia in a patient with poor oral hygiene: a case report

BACKGROUND

Streptococcus cristatus is a member of the Mitis streptococcus group. Like other members of this group, it resides on mucosal surfaces of the oral cavity. However, little is known about its ability to cause disease as there are only a handful of cases in the literature. Two of these cases involved infective endocarditis with significant complications. However, these cases involved additional microbes, limiting the inferences about the pathogenicity of Streptococcus cristatus.

CASE PRESENTATION

A 59-year-old African American male with end-stage cryptogenic cirrhosis and ascites presented with fatigue and confusion. A paracentesis was negative for spontaneous bacterial peritonitis, but two separate blood cultures grew Streptococcus cristatus. Our patient had a history of dental caries and poor oral hygiene, which were likely the source of the infection. Echocardiograms revealed new aortic regurgitation, indicating "possible endocarditis" per the Modified Duke Criteria. However, since his clinical picture and cardiac function were reassuring, we elected against treatment for infective endocarditis. He was treated for bacteremia with a 2-week course of cephalosporins consisting of 8 days of ceftriaxone, transitioning to cefpodoxime after discharge. Despite having end-stage liver disease, our patient did not experience any significant complications from the infection.

CONCLUSION

A patient with end-stage cirrhosis and poor oral hygiene developed bacteremia with an oral bacterium called Streptococcus cristatus. Unlike previous cases in literature, our patient did not meet criteria for a definitive diagnosis of infective endocarditis, and he experienced no other complications from the infection. This suggests coinfectants may have been primarily responsible for the severe cardiac sequelae in prior cases, whereas isolated Streptococcus cristatus infection may be relatively mild.

Antibiotic associated diarrhea in outpatient pediatric antibiotic therapy

BACKGROUND

Antibiotic-associated diarrhea is one of the most frequent side effects of antimicrobial therapy. We assessed the epidemiological data of antibiotic-associated diarrhea in pediatric patients in our region.

METHODS

The prospective multi-center study included pediatric patients who were initiated an oral antibiotic course in outpatient clinics and followed in a well-established surveillance system. This follow-up system constituded inclusion of patient by the primary physician, supply of family follow-up charts to the family, passing the demographics and clinical information of patient to the Primary Investigator Centre, and a close telephone follow-up of patients for a period of eight weeks by the Primary Investigator Centre.

RESULTS

A result of 758 cases were recruited in the analysis which had a frequency of 10.4% antibiotic-associated diarrhea. Among the cases treated with amoxicillin-clavulanate 10.4%, and cephalosporins 14.4% presented with antibiotic-associated diarrhea. In the analysis of antibiotic-associated diarrhea occurrence according to different geographical regions of Turkey, antibiotic-associated diarrhea episodes differed significantly (p = 0.014), particularly higher in The Eastern Anatolia and Southeastern Anatolia. Though most commonly encountered with cephalosporin use, antibiotic-associated diarrhea is not a frequent side effect.

CONCLUSION

This study on pediatric antibiotic-associated diarrhea displayed epidemiological data and the differences geographically in our region.

A comparative performance evaluation of cephalosporin's drugs for fluoride recognition

In this manuscript, readily available cephalosporin's drugs cefuroxime axetil (L1) cefpdoxime proxetil (L2), and cefditoren pivoxil (L3) possess dihydrothiazine ring as signaling unit, and -NH groups as the binding site were used for the sensing of fluoride (F^-) ions. In the presence of F^-, the drug selectively portrayed a naked-eye detectable color change from colorless. The binding constant of 1:1 stoichiometric complex of L1, L2, and L3 with F^- was found to be 2.36 × 10⁴ M^-1, 2.44 × 10³ M^-1 and 1.02 × 10⁴ M^-1 respectively. The lowest detection limit (LOD) of F^- was found to be 11 µM (209 ppb) with drug L1 and L2. The binding mechanism of the drug with F^- was studied by ¹H and ¹⁹F nuclear magnetic resonance (NMR) spectral titration, electrospray ionization mass spectra (ESI-MS) analysis, and density functional theory (DFT) studies. The presence of F^- was monitored in various spiked water and Colgate toothpaste samples. Overall, cephalosporin's drug demonstrates a promising potential for the detection of F^- ions in the semi-aqueous phase.

The Combined Use of Chronological and Morphological Criteria in the Evaluation of Immediate Penicillin Reactions: Evidence From a Large Study

BACKGROUND

Immediate hypersensitivity reactions to penicillins are often labeled on the basis of a similar set of symptoms, but a key feature of these reactions that can be reproduced in diagnostic testing may be the timing of a reaction in relation to the dose administration.

OBJECTIVE

To determine whether the timing of a reaction in response to the last dose of a penicillin would predict the results of diagnostic testing.

METHODS

We evaluated 1074 patients by performing skin tests, serum specific IgE assays (ImmunoCAP), and challenges. Patients who were evaluated by us more than 6 months after their reactions and found negative were reevaluated within 2 to 4 weeks.

RESULTS

Patients who had reacted within 1 hour after the first dose, within 1 hour after subsequent doses, more than 1 hour to within 6 hours after the first dose, or more than 1 hour to within 6 hours after subsequent doses were classified as group A (758 individuals), B (92), C (67), or D (157), respectively. Penicillin hypersensitivity was diagnosed in 707 patients (65.8%) by skin tests (407 patients, 57.6%), ImmunoCAP (47, 6.6%), both tests (232, 32.8%), or challenges (21, 3%). A conversion to allergy-test positivity occurred in 7 of 10 patients with anaphylactic reactions and in 1 of 28 patients with other reactions who were reevaluated after negative challenges. The rate of penicillin-allergic patients in groups A, B, C, and D was 85%, 35.9%, 35.8%, and 3.8%, respectively. Only 1 of 107 patients reporting cutaneous reactions lasting more than 1 day had positive results to allergy tests.

CONCLUSIONS

IgE-mediated hypersensitivity can be diagnosed by skin tests in about 70% of subjects who react within 1 hour (eg, patients from groups A and B). This hypersensitivity can be lost over time, as demonstrated by the negativization of allergy tests in follow-up studies. In subjects with anaphylactic reactions, however, it is advisable to not consider this phenomenon definitive. In fact, a conversion to allergy test positivity can be observed in up to 20% of such subjects retested after negative challenges.

Clinical features and treatment strategies of febrile urinary tract infection caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae in children: a multicenter retrospective observational study in Japan

OBJECTIVES

The incidence of infections caused by extended-spectrum beta-lactamase (ESBL)-producing bacteria has increased. This study aimed to clarify the risk factors and treatment strategies for febrile urinary tract infection (fUTI) caused by ESBL-producing bacteria in Japanese children.

METHODS

A retrospective observational study was conducted in 21 hospitals among children aged <16 years diagnosed with an fUTI between 2008 and 2017. Clinical data of children with fUTI caused by ESBL-producing and non-ESBL-producing bacteria were compared.

RESULTS

Of the 2049 cases of fUTI, 147 (7.2%) were caused by ESBL-producing bacteria. Children in the ESBL group were more likely to have a history of recent antibiotic use or prophylactic antibiotic use, and experience recurrent UTIs (P <0.001) compared with those in the non-ESBL group. Of the 124 cases of fUTI due to ESBL-producing bacteria that were reviewed, 20 and 100 had concordant and discordant antibiotic use, respectively, and four had unknown antibiotic susceptibility. The median time from the start of treatment to fever resolution was 24 hours and did not differ significantly by therapy group (P = 0.39).

CONCLUSION

ESBL-producing bacteria should be considered in children with recurrent UTIs and recent antibiotic use. Most children with fUTI experience clinical improvement regardless of the choice of antibiotic.

In silico studies of Mpro and PLpro from SARS-CoV-2 and a new class of cephalosporin drugs containing 1,2,4-thiadiazole

The SARS-CoV-2 proteases Mpro and PLpro are important targets for the development of antivirals against COVID-19. The functional group 1,2,4-thiadiazole has been indicated to inhibit cysteinyl proteases, such as papain and cathepsins. Of note, the 1,2,4-thiadiazole moiety is found in a new class of cephalosporin FDA-approved antibiotics: ceftaroline fosamil, ceftobiprole, and ceftobiprole medocaril. Here we investigated the interaction of these new antibiotics and their main metabolites with the SARS-CoV-2 proteases by molecular docking, molecular dynamics (MD), and density functional theory (DFT) calculations. Our results indicated the PLpro enzyme as a better in silico target for the new antibacterial cephalosporins. The results with ceftaroline fosamil and the dephosphorylate metabolite compounds should be tested as potential inhibitor of PLpro, Mpro, and SARS-CoV-2 replication in vitro. In addition, the data here reported can help in the design of new potential drugs against COVID-19 by exploiting the S atom reactivity in the 1,2,4-thiadiazole moiety.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11224-022-02036-5.

Potential Application of Cephalosporins Carried in Organic or Inorganic Nanosystems Against Gram-negative Pathogens

Cephalosporins are β-lactam antibiotics, classified into five generations and extensively used in clinical practice against infections caused by Gram-negative pathogens, including Enterobacteriaceae and P. aeruginosa. Commercially, conventional pharmaceutical forms require high doses to ensure clinical efficacy. Additionally, β-lactam resistance mechanisms, such as the production of enzymes (called extended-spectrum β-lactamases) and the low plasma half-life of these antibiotics have been challenging in clinical therapy based on the use of cephalosporins. In this context, its incorporation into nanoparticles, whether organic or inorganic, is an alternative to temporally and spatially control the drug release and improve its pharmacokinetic and pharmacodynamic limitations. Considering this, the present review unites the cephalosporins encapsulated into organic and inorganic nanoparticles against resistant and nonresistant enterobacteria. We divide cephalosporin generation into subtopics in which we discuss all molecules approved by regulatory agencies. In addition, changes in the side chains at positions R1 and R2 of the central structure of cephalosporins for all semisynthetic derivatives developed were discussed and presented, as the changes in these groups are related to modifications in pharmacological and pharmacokinetic properties, respectively. Ultimately, we exhibit the advances and differences in the release profile and in vitro activity of cephalosporins incorporated in different nanoparticles.

Lipophilicity study of different cephalosporins: Computational prediction of minimum inhibitory concentration using salting-out chromatography

The chromatographic and lipophilicity characters of seven cephalosporins of different four classes (cephradine, cefaclor, cefprozil, cefixime, cefotaxime, ceftazidime and cefepime) were examined by salting out thin-layer chromatography (SOTLC). SOTLC using ammonium sulfate salt was employed to predict the lipophilicity of the proposed drugs via their retention behavior. The calculated R_M0 values showed liner relationship with the molar concentration of ammonium sulfate in mobile phase in the range of 0.5-2.5 mol/L. Additionally, quantitative structure retention relationship (QSRR) was generated to figure out the relationship between the calculated chromatographic parameters (R_M0 and C₀) and log P of the studied cephalosporins. Good correlations were found between the chromatographically obtained retention parameters (R_M0 and C₀) and some molecular descriptors of the examined drugs. Furthermore, an efficient QSAR model was carried out using the calculated chromatographic parameters (R_M0 and C₀) and log P of the studied cephalosporins to predict minimum inhibitory concentration (MIC) and blood brain barrier (BBB) penetration of the examined drugs. The study was extended to separate and quantify the selected antibiotics in their pure forms and pharmaceutical formulations. Normal phase thin layer chromatographic (NP-TLC) method using a usable developing system of acetone: methanol: water: ammonium hydroxide: glacial acetic acid (90: 10: 18: 3: 2, by volume) was successfully applied to resolve the studied cephalosporins. Linearity was achieved in the range of 0.2-3 µg/mL for most of the studied antibiotics. The developed SOTLC method can be considered as a good start alternative to reversed phase thin layer chromatography (RP-TLC) for prediction of the lipophilic properties of examined cephalosporins. Moreover, the proposed NP-TLC densitometric method can be easily applied for quality control analysis of the chosen drugs and other structurally related components.

75% negative skin test results in patients with suspected hypersensitivity to beta-lactam antibiotics: Influencing factors and interpretation of test results

Background

The diagnostic approach for beta-lactam (BL) drug hypersensitivity reactions (DHR) is based on the history, clinical signs, skin tests (ST), in vitro tests, and drug provocation tests (DPT). The aim of this study was to assess the performance of an allergy workup with ST in a real-world use.

Methods

In this cross-sectional study the rate of positive ST in subjects with suspected DHR to penicillins and cephalosporins was investigated. Of special interest were correlations of ST positivity: 1) to the time intervals between index reaction and the allergic work-up, 2) time interval from drug exposure to the onset of signs, 3) pattern of manifestation in delayed DHR and involvement of test area in the index reaction, and 4) potential advantage of patch testing in delayed DHR.

Results

175 patients were included between January 2018 and April 2019 (63.4% female), 45 (25.7%) with immediate DHR manifestation and 130 with delayed DHR manifestation (74.3%). A total of 44 patients (25.1%) had a positive ST (immediate DHR 37.8% versus 20.0% in delayed DHR). ST positivity decreased in both groups after 3 years from 47.8% [95%CI 29.2-67] to 23.5% [95%CI 9.6-47.3] in immediate DHR and 23.0% [95%CI 15-4-32.9] to 12.9% [95%CI 5.1-28.9] in delayed DHR. The proportion of positive ST was higher in patients with more severe forms of delayed DHR, and in subjects with a shorter latency period of onset of symptoms after drug exposure: 0-3d: 29.5% [95%CI 19.6-41.9] vs. >3d: 11.6% [95%CI 6.0-21.2]). No sensitization was shown in delayed urticaria or angioedema. ST done outside the skin area involved during the index reaction were negative in all cases (0/38 vs. 26/84 in cases with involved area). The combination of patch test and intradermal test (IDT) revealed an additional positive result in 2/77 cases. Additional in vitro testing reduced the proportion of negative test results to 72%.

Conclusion

In most patients with negative test results, we could not clarify the cause of the BL-associated adverse events even with further investigations (including DPT). How to prevent new drug-induced adverse events in such patients has hardly been investigated yet. Corresponding cohort studies could improve the data situation.

Risk Stratification as a Predictive Factor for Cephalosporin Allergy: A Case-Controlled Study

BACKGROUND

Compared to penicillin, cephalosporin allergies are less common in children, and their diagnostic approach is less standardized. A recent European Academy of Allergy and Clinical Immunology position paper provided a risk stratification system for patients with suspected β-lactam hypersensitivity reactions.

OBJECTIVE

This study aimed to evaluate risk stratification and predicting factors for confirmed cephalosporin hypersensitivity.

METHODS

The case-controlled study included patients with confirmed cephalosporin hypersensitivity (skin tests, n = 53; drug provocation, n = 19). For each patient, 2 age- and gender-matched control subjects were included in the study. Data were retrieved from patients' records and analyzed retrospectively. Risk stratification was performed according to the severity of index reactions, which was initially divided as high and low risk and then further divided as immediate and nonimmediate.

RESULTS

According to risk stratification, the patient and control groups were divided as follows: high-risk immediate (66.7% vs. 13%, respectively), high-risk delayed (1.4% vs. 8.3%, respectively), low-risk immediate (16.7% vs. 16%, respectively), and low-risk delayed (15.3% vs. 62.9%, respectively). Immediate reactions (odds ratio [OR]: 12.1, 95% confidence interval [CI]: 9-24.8, p < 0.001) and high-risk reactions (OR: 7.8, 95% CI: 4.1-14.6, p < 0.001) were associated with confirmed cephalosporin hypersensitivity in univariate analysis. Multivariate regression analysis indicated that immediate reactions (OR: 7.5, 95% CI: 3.3-16.8, p < 0.001) and high-risk reactions (OR: 5.2, 95% CI: 2.1-12.9, p < 0.001) were significant risk factors for the prediction of cephalosporin hypersensitivity.

CONCLUSION

This model can be applied in children with suspected cephalosporin allergy. Skin testing provides diagnostic information in high-risk patients with immediate reactions and reduces the need for drug provocation testing in these patients. It is highly likely to confirm the diagnosis of low-risk patients directly with provocation tests without skin tests. High-risk and immediate reactions were found to be predictive factors for confirmed cephalosporin allergy.

Antibacterial agents used in COVID-19: A systematic review and meta-analysis

There have been speculations regarding rise in antimicrobial resistance (AMR) globally owing to indiscriminate antibiotic usage during the COVID-19 pandemic. To curb the menace through decisive policies, it is essential to assess the antibiotics, particularly the antibacterial agents. This systematic review and meta-analysis were performed to assess antibiotic use in COVID-19 patients. A thorough systematic search was undertaken in databases like PubMed, Cochrane library, Google Scholar, World Health Organization (WHO) database and clinicaltrials.gov by two independent reviewers for articles in English published from January 1, 2019 to October 31, 2020. Studies were included if they assessed confirmed COVID-19 cases and mentioned the use of antibiotics. The primary outcome was the proportion of COVID-19 patients subjected to specific antibacterial agents. An attempt to stratify the data based on study settings and disease severity was also performed. Of the total 6012 studies screened, 40 were eligible for qualitative review and 19 for meta-analysis. Specific antibacterial agents were mentioned in 23 studies (57.5%). In the random effect meta-analysis, pooled prevalence of azithromycin use was 24.5% (95% CI 22.9-26.2%) followed by cephalosporins as 26.6% (95% CI 24.9-28.4). None of the studies clearly specified indications for antibiotic use. Ten studies (25%) mentioned empirical use of antibiotics. Bacterial co-infections/secondary infections were documented in four studies with mean prevalence of infection of 1.9% (95% CI 1.2-2.8%). There is lack of data on use of specific antibacterial agents, indications for their use based on severity of infections and microbiological evidence of bacterial co-infections.

Cerium-modified iron oxides applied as catalysts in the heterogeneous Fenton system for degradation of cephalexin

The effect of incorporation of different amounts of cerium on iron oxides and different heat treatment temperatures was evaluated for the degradation of cephalexin (CEX) using heterogeneous Fenton and photo-Fenton processes. The materials were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), specific area (BET), and zeta potential (ZP). The conversion of magnetite to maghemite was observed when a 140 °C thermal treatment was applied. The insertion of cerium resulted in a loss of the uniform spherical shape of the particles. The material containing the lowest amount of cerium (0.5% w/w) presented an increase in the specific area from 91.2 to 171.6 m² g^-1 relative to the pure iron oxide, while with 2% (w/w) a decrease to 99.2 m² g^-1 was observed for the materials treated at 70 °C. The same behavior was observed for materials treated at 140 °C, however, with smaller areas. At pH 6.0, a low catalytic activity was observed contrasting to the high consumption of H₂O₂, suggesting its catalytic decomposition into water and oxygen. This was confirmed by the very low production of HO• in the degradation system. On the other hand, the high production of HO• was observed at pH 3.5, which was chosen as a working pH. The material treated at 140 °C and containing 1% Ce (w/w) was the highlight, promoting degradation of 0.052 mg of CEX per m² area of the catalyst after 150 min using 1.0 mmol L^-1 of H₂O₂. The CEX intermediates identified indicated hydroxylation as the major route of degradation.

Ceftolozane/tazobactam and ceftazidime/avibactam antimicrobial activity against clinically relevant gram-negative bacilli isolated in Mexico

INTRODUCTION

There is limited information on the effectiveness of ceftolozane/tazobactam and ceftazidime/avibactam combinations on clinically relevant strains isolated in Mexico.

OBJECTIVE

To determine the antimicrobial profile of both antibiotic combinations in our community.

METHOD

The present research study was prospective, descriptive and cross-sectional. Clinically relevant strains isolated from pure-strain cultures were included during the period from August 2018 to January 2019 in Mexicali, Baja California, Mexico.

RESULTS

74 enterobacteriaceae and 19 Pseudomonas aeruginosa strains were analyzed; the percentage of sensitivity of ceftazidime/avibactam was 100 % for enterobacteriaceae and 72.7 % for Pseudomonas aeruginosa; the percentage of sensitivity of ceftolozane/tazobactam for enterobacteriaceae was 90.5 % and 72.7 % for Pseudomonas aeruginosa.

CONCLUSIONS

The ceftolozane/tazobactam and ceftazidime/avibactam combinations offer good antimicrobial sensitivity in vitro, both for ESBL-producing enterobacteriaceae and Pseudomonas aeruginosa. More data are required to assess clinical response in patients receiving these antibiotic combinations.

INTRODUCCIÓN

Existe poca información acerca de la efectividad de las combinaciones ceftolozano/tazobactam y ceftazidima/avibactam en cepas clínicamente relevantes aisladas en México.

OBJETIVO

Determinar el perfil antimicrobiano de ambos antibióticos en nuestra comunidad.

MÉTODO

El presente estudio de investigación fue prospectivo, descriptivo y transversal. Se incluyeron cepas clínicamente relevantes aisladas a partir de cultivos de cepa pura durante el periodo de agosto de 2018 a enero de 2019 en Mexicali, Baja California, México.

RESULTADOS

Se analizaron 74 cepas de enterobacterias y 19 cepas de Pseudomonas aeruginosa; el porcentaje de sensibilidad de ceftazidima/avibactam fue de 100 % contra enterobacterias y de 72.7 % contra Pseudomonas aeruginosa; el porcentaje de sensibilidad de ceftolozano/tazobactam fue de 90.5 % para enterobacterias y de 72.7 % para Pseudomonas aeruginosa.

CONCLUSIONES

Las combinaciones ceftolozano/tazobactam y ceftazidima/avibactam ofrecen buena sensibilidad antimicrobiana in vitro, tanto contra enterobacterias productoras de betalactamasas de espectro extendido como contra Pseudomonas aeruginosa. Se requieren más datos para valorar la respuesta clínica en pacientes que reciben esas combinaciones de antibióticos.

Comparison of antimicrobial resistances and clinical features in community-onset Escherichia coli and Klebsiella pneumoniae bacteremia

BACKGROUND/AIMS

The aim of this study was to compare antimicrobial resistance, clinical features, and outcomes of community-onset Escherichia coli (COEC) and Klebsiella pneumoniae (COKP) bacteremia.

METHODS

The medical records of patients diagnosed with E. coli or K. pneumoniae bacteremia in the emergency department of a 750-bed secondary care hospital in Daegu, Korea from January 2010 to December 2016 were retrospectively reviewed.

RESULTS

A total of 866 patients with COEC bacteremia and 299 with COKP bacteremia were enrolled. COEC bacteremia, compared to COKP bacteremia, had higher rates of 3rd generation cephalosporin (3GC) (18.8% vs. 8.4%, p < 0.001) and f luoroquinolone (FQ) (30.4% vs. 8.0%, p < 0.001) resistance. The patients with COKP bacteremia had higher Charlson comorbidity indices (CCI) (1.8 ± 2.0 vs. 1.5 ± 1.8, p = 0.035), Pittsburgh bacteremia scores (PBS) (2.0 ± 2.6 vs. 1.3 ± 1.8, p < 0.001), and 30-day mortality (14.44% vs. 8.8%, p = 0.008) than the patients with COEC bacteremia. Age younger than 70 years, male sex, polymicrobial infections, pneumonia, intra-abdominal infection, PBS ≥ 2, and Foley catheter insertion were independent predictive factors for COKP bacteremia compared to COEC bacteremia in the multivariate analysis. CCI, PBS, and intensive care unit admission were independent risk factors for 30-day mortality in the multivariate analysis.

CONCLUSION

3GCs and FQs are still useful for the empirical treatment of patients with probable COKP bacteremia. The patients with COKP bacteremia had worse outcomes because of its greater severity and more frequent underlying comorbidities.

Evaluation of Clinical Properties and Diagnostic Test Results of Cephalosporin Allergy in Children

INTRODUCTION

Beta-lactams (BLs) are one of the most frequent causes of drug hypersensitivity reactions (HRs), and cephalosporins are a widely used subclass of BLs, especially in children. The aim of this study was to evaluate the clinical features and diagnostic test results of pediatric patients evaluated for suspected cephalosporin allergy.

METHODS

This study included patients who presented to our pediatric allergy clinic with a history of reactions attributed to cephalosporins between January 1, 2011, and December 31, 2019, and whose diagnostic tests were completed for the diagnosis.

RESULTS

This study included 120 pediatric patients and 69 (57.5%) of them were girls. The median age was 38.63 (interquartile range 10.5-85.7) months. Reactions occurring within 1 h of drug intake were reported in 33 patients (27.5%). Reactions were maculopapular rash in 55 (45.8%) patients, urticaria and/or angioedema in 49 (40.8%), anaphylaxis in 11 (9.2%), severe cutaneous drug reaction in 4 (3.3%), and fixed drug reaction in 1 patient (0.83%). The most frequently suspected agent was cefixime in 41 patients (34.2%). In total, 30 (25%) patients were diagnosed as having cephalosporin hypersensitivity. Confirmation of HRs was also significantly more frequent among patients who were older (p: 0.000), who had taken the drug parenterally (p: 0.000) and with immediate reactions (p: 0.000).

CONCLUSION

Cephalosporin allergy has been confirmed in approximately one-fourth of the patients evaluated for suspected cephalosporin allergy. Confirmation of HRs was significantly more common among patients who were older, had immediate reactions, and had taken the drug parenterally.

Screening of natural compounds for identification of novel inhibitors against β-lactamase CTX-M-152 reported among Kluyvera georgiana isolates: An in vitro and in silico study

Multidrug resistance due to the expression of extended spectrum β-lactamases (ESBLs) by bacterial pathogens is an alarming health concern with huge socio-economic burden. Here, 102 bacterial isolates from Wastewater treatment plants (WTPs) were screened for resistance to different antibiotics. Kirby-Bauer method and phenotypic disc confirmatory test confirmed the prevalence of 20 ESBLs. Polymerase chain reaction-based detection confirmed 11 bla_CTX-M positive bacterial isolates. Genotyping of bacterial isolates by 16S rRNA gene sequencing showed the dissemination of bla_CTX-M in Escherichia fergusonii, Escherichia coli, Shigella sp., Kluyvera georgiana and Enterobacter sp. Amongst Kluyvera georgiana isolates, two were harboring bla_CTX-M-152. The 3D model of CTX-M-152 protein was generated using SwissProt and characterized by Ramachandran plot and SAVES. A library of natural compounds was screened to identify novel CTX-M-152 inhibitor(s). High-throughput virtual screening (HTVS), standard precision (SP) and extra precision (XP) docking led to the identification of five natural compounds (Naringin dihydrochalcone, Salvianolic acid B, Inositol, Guanosine and Ellagic acid) capable of binding to active site of CTX-M-152. Futher, characterization by MM-GBSA (Molecular Mechanism General Born Surface Area), and ADMET (Adsorption, Distribution, Metabolism, Excretion and Toxicity) showed that Ellagic acid was the most potent inhibitor of CTX-M-152. Molecular dynamics simulation also confirmed that Ellagic acid form a stable complex with CTX-M-152. The ability of Ellagic acid to inhibit growth of bacteria harboring CTX-M-152 was confirmed by MIC (Minimum Inhibitory Concentration; broth dilution method) and Zone of Inhibition (ZOI) studies with respect to Cefotaxime. The identification of a novel inhibitor of CTX-M-152 from a natural source holds promise for employment in the control of bacterial infections.

Enterobacter cloacae colonisation and infection in a neonatal intensive care unit: retrospective investigation of preventive measures implemented after a multiclonal outbreak

BACKGROUND

Enterobacter cloacae species is responsible for nosocomial outbreaks in vulnerable patients in neonatal intensive care units (NICU). The environment can constitute the reservoir and source of infection in NICUs. Herein we report the impact of preventive measures implemented after an Enterobacter cloacae outbreak inside a NICU.

METHODS

This retrospective study was conducted in one level 3 NICU in Lyon, France, over a 6 year-period (2012-2018). After an outbreak of Enterobacter cloacae infections in hospitalized neonates in 2013, several measures were implemented including intensive biocleaning and education of medical staff. Clinical and microbiological characteristics of infected patients and evolution of colonization/infection with Enterobacter spp. in this NICU were retrieved. Moreover, whole genome sequencing was performed on 6 outbreak strains.

RESULTS

Enterobacter spp. was isolated in 469 patients and 30 patients developed an infection including 2 meningitis and 12 fatal cases. Preventive measures and education of medical staff were not associated with a significant decrease in patient colonisation but led to a persistent decreased use of cephalosporin in the NICU. Infection strains were genetically diverse, supporting the hypothesis of multiple hygiene defects rather than the diffusion of a single clone.

CONCLUSIONS

Grouped cases of infections inside one setting are not necessarily related to a single-clone outbreak and could reveal other environmental and organisational problematics. The fight against implementation and transmission of Enterobacter spp. in NICUs remains a major challenge.

Bacterial Resistance to Cephalosporin Treatment in Elderly Stable Patients Hospitalized With a Urinary Tract Infection

BACKGROUND

It is unclear if parenteral cephalosporin treatment is appropriate in stable elderly patients hospitalized with a urinary tract infection (UTI) in settings with a high prevalence of bacterial resistant organisms.

METHODS

We selected 934 consecutive stable patients aged ≥65 years with a UTI, 94.4% (n = 882) treated with a parenteral cephalosporin. Patients were divided into those with and without bacterial resistance to initial antibiotic therapy (BRIAT). Outcome measures were response to antibiotic therapy at 72 hours, prolonged hospitalization (>5 days) and mortality.

RESULTS

There were 316 patients (33.8%) with BRIAT. At 72 hours, 33.9% (107/316) did not respond to initial treatment. The odds of a prolonged hospitalization was 2.1 (95% confidence interval-1.6-2.9), but no patient with BRIAT died from urosepsis (0%, 95% confidence interval-0-1.2%).

CONCLUSIONS

In elderly stable patients hospitalized with a UTI, treatment with a parenteral cephalosporin might be appropriate despite a high prevalence of resistant organisms.

New cephalosporins for the treatment of pneumonia in internal medicine wards

The burden of hospital admission for pneumonia in internal medicine wards may not be underestimated; otherwise, cases of pneumonia are a frequent indication for antimicrobial prescriptions. Community- and hospital-acquired pneumonia are characterized by high healthcare costs, morbidity and non-negligible rates of fatality. The overcoming prevalence of resistant gram-negative and positive bacteria (e.g., methicillin-resistant Staphylococcus aureus, penicillin and ceftriaxone-resistant Streptococcus pneumoniae, extended-spectrum β-lactamases and carbapenemases producing Enterobacteriaceae) has made the most of the first-line agents ineffective for treating lower respiratory tract infections. A broad-spectrum of activity, favourable pulmonary penetration, harmlessness and avoiding in some cases a combination therapy, characterise new cephalosporins such as ceftolozane/tazobactam, ceftobiprole, ceftazidime/avibactam and ceftaroline. We aimed to summarise the role and place in therapy of new cephalosporins in community- and hospital-acquired pneumonia within the setting of internal medicine wards. The “universal pneumonia antibiotic strategy” is no longer acceptable for treating lung infections. Antimicrobial therapy should be individualized considering local antimicrobial resistance and epidemiology, the stage of the illness and potential host factors predisposing to a high risk for specific pathogens.

Bacterial spectrum and antibiotic resistance of urinary tract infections in patients treated for upper urinary tract calculi: a multicenter analysis

The purpose of this study is to collect information on the bacterial resistance to antibiotics of bacteria isolated from urine cultures of patients treated for upper urinary tract calculi. Data of patients with urinary tract infection and urolithiasis were retrospectively reviewed to collect information on age, gender, stone size, location, hydronephrosis, procedure of stone removal and antibiotic treatment, identification and susceptibility of pathogens, symptoms, and infectious complications. A total of 912 patients from 11 centers in 7 countries (Bulgaria, Greece, Italy, North Macedonia, Spain, and Turkey) were studied. Mean age was 54 ± 16 years and M/F ratio 322/590. Out of 946 microbial isolates, the most common were E. coli, Gram-positive, KES group (Klebsiella, Enterobacter, Serratia), Proteus spp., and P. aeruginosa. Carbapenems, piperacillin/tazobactam and amikacin showed low resistance rates to E. coli (2.5%, 7%, and 3.6%) and Proteus spp. (7.7%, 16%, and 7.4%), but higher rates were observed with Klebsiella spp., P. aeruginosa, and Gram-positive. Fosfomycin had resistance rates less than 10% to E. coli, 23% to KES group, and 19% to Gram-positive. Amoxicillin/clavulanate, cephalosporins, quinolones, and TMP/SMX showed high resistance rates to most bacterial strains. High rates of antibiotic resistance were observed in patients candidate to stone treatment from South-Eastern Europe. The empirical use of antibiotics with low resistance rates should be reserved to the most serious cases to avoid the increase of multidrug resistant bacteria. Basing on our results, carbapenems, piperacillin/tazobactam, and amikacin may be a possible option for empiric treatment of urinary stone patients showing systemic symptoms.

Validation and clinical application of a multiplex high performance liquid chromatography - tandem mass spectrometry assay for the monitoring of plasma concentrations of 12 antibiotics in patients with severe bacterial infections

OBJECTIVE

Unpredictable pharmacokinetics of antibiotics in patients with life-threatening bacterial infections is associated with drug under- or overdosing. Therapeutic drug monitoring (TDM) may guide dosing adjustment aimed at maximizing antibacterial efficacy and minimizing toxicity. Rapid and accurate analytical methods are key for real-time TDM. Our objective was to develop a robust high-performance liquid chromatography-tandem mass spectrometry method (HPLC-MS/MS) for multiplex quantification of plasma concentrations of 12 antibiotics: imipenem/cilastatin, meropenem, ertapenem, cefepime, ceftazidime, ceftriaxone, piperacillin/tazobactam, amoxicillin, flucloxacillin, rifampicin, daptomycin.

METHODS

A single extraction procedure consisting in methanol plasma protein precipitation and H₂O dilution was used for all analytes. After chromatographic separation on an Acquity UPLC HSS-T3 2.1 × 50 mm, 1.8 µm (Waters®) column, quantification was performed by electro-spray ionisation-triple quadrupole mass spectrometry with selected reaction monitoring detection. Antibiotics were divided in two pools of calibration according to the frequency of analyses requests in the hospital routine antibiotic TDM program. Stable isotopically-labelled analogues were used as internal standards. A single analytical run lasted less than 9 min.

RESULTS

The method was validated based on FDA recommendations, including assessment of extraction yield (96-113.8%), matrix effects, and analytical recovery (86.3-99.6%). The method was sensitive (lower limits of quantification 0.02-0.5 µg/mL), accurate (intra/inter-assay bias -11.3 to +12.7%) and precise (intra/inter-assay CVs 2.1-11.5%) over the clinically relevant plasma concentration ranges (upper limits of quantification 20-160 µg/mL). The application of the TDM assay was illustrated with clinical cases that highlight the impact on patients' management of an analytical assay providing information with short turn-around time on antibiotic plasma concentration.

CONCLUSION

This simple, robust high-throughput multiplex HPLC-MS/MS assay for simultaneous quantification of plasma concentrations of 12 daily used antibiotics is optimally suited for clinically efficient real-time TDM.

Transport systems, intracellular traffic of intermediates and secretion of β-lactam antibiotics in fungi

Fungal secondary metabolites are synthesized by complex biosynthetic pathways catalized by enzymes located in different subcellular compartments, thus requiring traffic of precursors and intermediates between them. The β-lactam antibiotics penicillin and cephalosporin C serve as an excellent model to understand the molecular mechanisms that control the subcellular localization of secondary metabolites biosynthetic enzymes. Optimal functioning of the β-lactam biosynthetic enzymes relies on a sophisticated temporal and spatial organization of the enzymes, the intermediates and the final products. The first and second enzymes of the penicillin pathway, ACV synthetase and IPN synthase, in Penicillium chrysogenum and Aspergillus nidulans are cytosolic. In contrast, the last two enzymes of the penicillin pathway, phenylacetyl-CoA ligase and isopenicillin N acyltransferase, are located in peroxisomes working as a tandem at their optimal pH that coincides with the peroxisomes pH. Two MFS transporters, PenM and PaaT have been found to be involved in the import of the intermediates isopenicillin N and phenylacetic acid, respectively, into peroxisomes. Similar compartmentalization of intermediates occurs in Acremonium chrysogenum; two enzymes isopenicillin N-CoA ligase and isopenicillin N-CoA epimerase, that catalyse the conversion of isopenicillin N in penicillin N, are located in peroxisomes. Two genes encoding MFS transporters, cefP and cefM, are located in the early cephalosporin gene cluster. These transporters have been localized in peroxisomes by confocal fluorescence microscopy. A third gene of A. chrysogenum, cefT, encodes an MFS protein, located in the cell membrane involved in the secretion of cephalosporin C, although cefT-disrupted mutants are still able to export cephalosporin by redundant transporters. The secretion of penicillin from peroxisomes to the extracellular medium is still unclear. Attempts have been made to identify a gene encoding the penicillin secretion protein among the 48 ABC-transporters of P. chrysogenum. The highly efficient secretion system that exports penicillin against a concentration gradient may involve active penicillin extrusion systems mediated by vesicles that fuse to the cell membrane. However, there is no correlation of pexophagy with penicillin or cephalosporin formation since inactivation of pexophagy leads to increased penicillin or cephalosporin biosynthesis due to preservation of peroxisomes. The penicillin biosynthesis finding shows that in order to increase biosynthesis of novel secondary metabolites it is essential to adequately target enzymes to organelles.

Investigation of plasmid-mediated resistance in E. coli isolated from healthy and diarrheic sheep and goats

Escherichia coli is zoonotic bacteria and the emergence of antimicrobial-resistant strains becomes a critical issue in both human and animal health globally. This study was therefore aimed to investigate the plasmid-mediated resistance in E. coli strains isolated from healthy and diarrheic sheep and goats. A total of 234 fecal samples were obtained from 157 sheep (99 healthy and 58 diarrheic) and 77 goats (32 healthy and 45 diarrheic) for the isolation and identification of E. coli. Plasmid DNA was extracted using the alkaline lysis method. Phenotypic antibiotic susceptibility profiles were determined against the three classes of antimicrobials, which resistance is mediated by plasmids (Cephalosporins, Fluoroquinolone, and Aminoglycosides) using the disc-diffusion method. The frequency of plasmid-mediated resistance genes was investigated by PCR. A total of 159 E. coli strains harbored plasmids. The isolates antibiogram showed different patterns of resistance in both healthy and diarrheic animals. A total of (82; 51.5%) E. coli strains were multidrug-resistant. rmtB gene was detected in all Aminoglycoside-resistant E. coli, and the ESBL-producing E. coli possessed different CTX-M genes. Similarly, fluoroquinolone-resistant E. coli possessed different qnr genes. On the analysis of the gyrB gene sequence of fluoroquinolone-resistant E. coli, multiple point mutations were revealed. In conclusion, a high prevalence of E. coli with high resistance patterns to antimicrobials was revealed in the current study, in addition to a wide distribution of their resistance determinants. These findings highlight the importance of sheep and goats as reservoirs for the dissemination of MDR E. coli and resistance gene horizontal transfer.

The effect of different antimicrobial treatment regimens on the faecal shedding of ESBL-producing Escherichia coli in horses

Fourth-generation cephalosporins can select for extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in horses, but it is unknown to what extent this occurs compared to penicillin/gentamicin combination treatment. The objective was to evaluate the effect of different antimicrobial treatments on faecal shedding and diversity of ESBL-producing Escherichia coli (ESBL-EC) in horses. Upon hospital admission, 86 horses in need of antimicrobial treatment or prophylaxis were randomly allocated to receive penicillin and gentamicin (PG) or cefquinome (CEF). Untreated horses were included as controls (NOAMD, n = 33). Faecal samples from admission (T1), 3 days after admission (T2), and faecal swabs 28 days after discharge (T3) were cultured selectively. Differences in prevalence (T1, T2, T3) and counts (T1, T2) of ESBL-EC between groups and over time were analysed. On a subset of ESBL-EC isolates, antimicrobial susceptibility testing (n = 45) and whole-genome sequencing followed by SNP-analysis (n = 46) were performed. The prevalence of ESBL-EC at T1 was 12 % with no significant difference between groups. In all groups, significantly higher carriage rates were observed at T2 and T3 compared to T1. Carriage and counts of ESBL-EC at T2 were significantly higher in treated compared to untreated horses. There was no significant difference between PG and CEF at any time points. Despite a large genetic diversity, indistinguishable ESBL clones were observed in different horses over time. In conclusion, antimicrobial treatment and hospitalization increased prevalence and counts of ESBL-EC, and transmission of ESBL-EC in the hospital was suspected. These findings highlight the importance of antimicrobial stewardship and infection control practices in equine medicine.

[Analysis of drug resistance pattern and genes of Salmonella.spp isolated from human infections in Anhui Province]

Objective: To investigate the drug resistance pattern and drug resistance genotypes of Salmonella. spp isolated from fecal specimens and anal swabs of diarrhea cases in Anhui Province. Methods: The 149 strains of Salmonella.spp isolated from feces and anal swabs of diarrhea cases in Anhui Province from April to October 2017 were selected. The serotypes of Salmonella.spp were identified by slide agglutination. The susceptibility of all strains to 14 antibiotics were determined by micro-broth dilution method. Sixty of the cephalosporin-resistant antibiotics were selected. The β-lactamase encoding genes bla(TEM), bla(SHV), bla(OXA-1), bla(OXA-2), bla(PER), bla(CMY), bla(CTX-M), and colistin resistance genes mcr-1 and mcr-2 were performed using the multi-PCR method. Results: Of the 149 diarrhea cases, the median (P(25), P(75)) of the age was 5.0 (1.1, 38.5). The 92 of them were male and 54.4% were children. Of the 149 strains of Salmonella.spp, 105 strains had different degrees of resistance to 13 antibiotics other than imipenem. The resistance rate of ampicillin was 55.0% (82/149), which was the highest. 53.0% strains (79 strains) were multidrug resistant, main of which were Salmonella typhimurium and Salmonella enteritidis. A total of 53 resistance patterns were detected, and 10 strains were resistant to ampicillin-ampicillin/sulbactam-tetracycline-chloramphenicol-cefazolin-trimethoprim/sulfamethoxazole, which was the most common resistance pattern. Among the 60 cephalosporin resistant strains, 45 strains carried bla(TEM-1), 6 of which also carried bla(CTX-M-14) and 3 of which also carried bla(CTX-M-65). All the 32 strains carried only bla(TEM-1) show resistance to ampicillin and 31 of them show resistance to cefazolin. There were 2 strains showing negative results of gene detection. mcr-1 was detected in a multidrug resistant strain. Conclusion: The resistance of Salmonella.spp to ampicillin shows a serious situation in this region, and there were a number of multidrug resistant strains. The bla(TEM-1) was the major drug resistance gene detected in this research. Detection of the mcr-1 suggests the emergence of surveillance to colistin resistance of Salmonella.spp in this area.

Cefoperazone induces esterase B expression by EstR and esterase B enhances cefoperazone activity at the periplasm

The occurrence of antibiotic resistance bacteria has become a major threat to public health. We have recently discovered a transcriptional activator that belongs to MarR family, EstR, and an esterase B (EstB) with a newly proposed de-arenethiolase activity from Sphingobium sp. SM42. De-arenethiolase activity involves the removal of the small aromatic side chain of cephalosporin antibiotics as an excellent leaving group by the enzymatic CS bond cleavage. Here, we report the regulation of estB through EstR as an activator in response to a third generation cephalosporin, cefoperazone, antibiotic. Cefoperazone induced the expression of estB in wild type Sphingobium sp., but not in the estR knockout strain, and the induction was restored in the complemented strain. Moreover, we revealed the importance of EstB localization in periplasm. Since EsB has the ability to inactivate selected β-lactam antibiotics in vitro, it is possible that the enzyme works at the periplasmic space of Gram negative bacteria similar to β-lactamases. EstB was genetically engineered by incorporating NlpA binding motif, or OmpA signal sequence, or SpyTag-SpyCatcher to the estB gene to mobilize it to different compartments of periplasm; inner membrane, outer membrane, and periplasmic space, respectively. Surprisingly, we found that Sphingobium sp. SM42 and E. coli expressing EstB at the periplasm were more sensitive to cefoperazone. The possible drug enhancement mechanism by enzyme was proposed. This work might lead to a novel strategy to tackle antibiotic resistance problem.

New compounds for a good old class: Synthesis of two Β-lactam bearing cephalosporins and their evaluation with a multidisciplinary approach

Antimicrobial resistance is spreading massively in the world and is becoming one of the main health threats of the 21st century. One of the possible strategies to overcome this problem is to modify the known classes of antibiotics in a rational way, with the aim of tuning their efficacy. In this paper, we present the synthesis and the evaluation of the biological activity of a series of two β-lactam bearing cephalosporin derivatives, in which an additional isolated azetidinone ring, bearing different substituents, is joined to the classical cephalosporanic nucleus by a chain of variable length. A computational approach has been also applied in order to predict the molecular interactions between some representative derivatives and selected penicillin-binding proteins, the natural targets of β-lactam antibiotics. All these derivatives are active against Gram-positive bacteria, with MIC₁₀₀ comparable or even better than that of the reference antibiotic ceftriaxone, and show no or very low cytotoxic activity on different cell lines. Overall, these molecules appear to be able to exert their activity in particular against microorganisms belonging to some of the species more involved in the development of multidrug resistance.

Empirical fluoroquinolones versus broad-spectrum beta-lactams for Gram-negative bloodstream infections in the absence of antimicrobial resistance risk factors

OBJECTIVES

Increasing antimicrobial resistance rates limit empirical antimicrobial treatment options for Gram-negative bloodstream infections (GN-BSI). However, antimicrobial resistance may be predicted based on patient-specific risk factors using precision medicine concepts. This retrospective, 1:2 matched cohort examined clinical outcomes in hospitalized adults without major risk factors for antimicrobial resistance receiving empirical fluoroquinolones or broad-spectrum beta-lactams (BSBL) for GN-BSI at Prisma Health-Midlands hospitals in Columbia, SC, USA from January 2010 through June 2015.

METHODS

Multivariable logistic regression was used to examine early treatment failure at 72-96 h from GN-BSI. Cox proportional hazards regression was used to examine 28-day mortality and hospital length of stay (HLOS).

RESULTS

Among 74 and 148 patients receiving empirical fluoroquinolones and BSBL for GN-BSI, respectively, median age was 68 years, 159 (72%) were women, and 152 (68%) had a urinary source of infection. Early treatment failure rates were comparable in fluoroquinolone and BSBL groups (27% vs. 30%, respectively, odds ratio 0.82, 95% confidence intervals [CI] 0.43-1.54, P = 0.53), as well as 28-day mortality (8.9% vs. 9.7%, respectively, hazards ratio [HR] 0.74, 95% CI 0.26-1.90, P = 0.54). Median HLOS was 6.1 days in the fluoroquinolone group and 7.1 days in the BSBL group (HR 0.73, 95% CI 0.54-0.99, P = 0.04). Transition from intravenous to oral therapy occurred sooner in the fluoroquinolone group than in the BSBL group (3.0 vs. 4.9 days, P < 0.001).

CONCLUSIONS

In the absence of antimicrobial resistance risk factors, fluoroquinolones provide an additional empirical treatment option to BSBL for GN-BSI. Shorter HLOS in the fluoroquinolone group may be due to earlier transition from intravenous to oral antimicrobial therapy.

Synthesis and effect of pegylation on citric acid dendritic nano architectures anchored with cefotaxime sodium

In recent years dendrimers have fascinated the investigators towards targeted drug delivery because of their versatile framework and exhibit immense potentiality in entrapping drug moieties through host-guest interactions and serve as a promising vector in biological applications. The current investigation is focused on developing pegylated citric acid cefotaxime dendrimers through the divergent method and its characterization through spectroscopic, microscopic, thermal and microscopic techniques. Among the spectroscopic techniques, ¹H NMR and ¹³C NMR elucidated the key functional groups at various chemical shifts while ESI-MS pointed out the molecular weight of cefotaxime sodium in various generations. Similarly, FTIR, DSC, and AFM investigations detailed that the generations are devoid of incompatibilities, structural deformities and can be opted for targeted drug delivery. The drug entrapment studies and in-vitro drug release studies highlight CFTX G5 containing 92.4% entrapment efficacy and 83.8% drug release in 48 h and specifies a sustain release characteristics. In connection to the above, the in-vivo studies reveal a potent antibacterial activity against various gram-positive and gram-negative microorganisms with a decreased hemolysis and cytotoxicity effects and reflect a high margin of safety regarding pegylated CFTX dendrimers. Further, the antibacterial activities are supported through confocal microscopy that clarified the cellular uptake of dendritic molecules and their internalization.

Cefotaxime pharmacokinetics in Arabian camel (Camelus dromedarius) calves after single intravenous injection

Cefotaxime is a third-generation broad-spectrum cephalosporin acting on a wide range of Gram-positive and Gram-negative bacteria. In this work, the pharmacokinetics of cefotaxime were determined in dromedary camel calves by single intravenous injection of 10 mg/kg b.w. Cefotaxime levels were estimated by ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS/MS). Cefotaxime pharmacokinetics in camel calves obeyed three-compartment kinetics model. There was a central compartment and two peripheral, one shallow and one deep compartment. The shallow compartment equilibrates very rapidly with distribution half-life (t_1/2α) of 0.6 min, while the deep compartment has large distribution half-life (t_1/2β) of 42 min indicating slower uptake of cefotaxime. The elimination rate constant (γ = 0.04 h^-1) and elimination half-life (t_{1/2 γ}) = 15.46 h indicating slow elimination. In comparison with other animals, cefotaxime pharmacokinetics in camel calves showed potential wide distribution in multi-compartment, lower elimination constant, lower clearance and higher volume of distribution at steady state. This indicates substantial differences in cefotaxime pharmacokinetics in camel calves with a very characteristic ultra-rapid distribution into three-compartment and slow elimination.

Genotypic analysis of Italian MRSA strains exhibiting low-level ceftaroline and ceftobiprole resistance

The aim of this study was to address the involvement of PBP mutations in the bactericidal activity to novel cephalosporins, alone and in combination with daptomycin, in not-related multidrug-resistant methicillin-resistant Staphylococcus aureus strains isolated during a nationwide Italian survey. MICs determination and time-killing assays were performed and mecA, pbp1, pbp2, pbp3, pbp4, and gdpP genes were sequenced. Ten strains showed low-level resistance to ceftaroline and ceftobiprole. PBP2a sequence analysis identified four different mutations (N146K; N204K; T235I; E239K) uniquely present in the non-penicillin-binding domain (nPBD). Epidemiologically, this resistance was associated with the most widespread MDR Italian clone ST228-SCCmecI-t001/t041, confirming its proclivity to accumulate mutations, and it is also associated to substitutions in the GdpP signaling protein, involved in the maintenance of di-AMP balance, recently associated with resistance to beta-lactams. Despite these mutations, both drugs retained their potent in vitro bactericidal activity and showed a synergistic effect towards difficult-to-treat isolates.

Pharmacokinetic and pharmacodynamic considerations of cephalosporin use in children

Introduction: Cephalosporins are a major class of antibiotics, frequently used in children because of their remarkable antibacterial activity and excellent safety profile. Time above the minimal inhibitory concentration of the non-protein-bound fraction (fT>MIC) is the pharmacokinetic/pharmacodynamic parameter that correlates with the therapeutic efficacy. In the pediatric population, the inter-individual variability in cephalosporin pharmacokinetics is large because of maturational changes. However, the prescription of cephalosporins promotes emergence of Enterobacteriaceae producing broad-spectrum ß-lactamases.Areas covered: Here we describe in vitro activities and the main pharmacokinetic characteristics of cephalosporins in children. On the basis of these characteristics, we propose an estimation of the fT>MIC for each molecule as a tool to help optimize the use of cephalosporins. We also provide an inventory of the clinical use of cephalosporins and present prospects for the development of new molecules or associations to address the emergence of resistant strains.Expert opinion: Cephalosporins represent a heterogeneous group of antibiotics with various pharmacokinetics and in vitro antimicrobial activity that the clinician needs to master to optimize their use. However, their broad use plays a role in the emergence of broad-spectrum ß-lactamase-producing strains and must thus be restricted to probabilistic broad-spectrum therapy and situations without therapeutic alternatives.

Ambient temperature fabrication of a covalent organic framework from 1,3,5-triformylphloroglucinol and 1,4-phenylenediamine as a coating for use in open-tubular capillary electrochromatography of drugs and amino acids

A covalent organic framework (COF) named TpPa-1 was designed and synthesized at ambient temperature by an ultrasound-assisted method from 1,3,5-triformylphloroglucinol (Tp) and 1,4-phenylenediamine (Pa-1). It was utilized as a stationary phase in open-tubular capillary electrochromatography (OT-CEC). The column was coated with TpPa-1 using a covalent bonding strategy. The coated capillary was characterized by morphology, crystallography, and mesoporous analysis to confirm the successful fabrication. The OT-CEC method was utilized for the analysis of tetracyclines, sulfonamides, cephalosporins and amino acids with high-resolution (Rs > 1.81) and good precision (RSD < 4.9%). It takes about 12 h from COF preparation to OT-CEC separation. Graphical abstract A covalent organic framework (COF) named TpPa-1 was synthesized at ambient temperature by an ultrasound-assisted method from 1,3,5-triformylphloroglucinol (Tp) and 1,4-phenylenediamine (Pa-1). COF-TpPa-1 modified capillary column was utilized for the analysis of tetracyclines, sulfonamides, cephalosporins and amino acids with high-resolution and good precision.

Levels of outpatient prescribing for four major antibiotic classes and rates of septicemia hospitalization in adults in different US states - a statistical analysis

BACKGROUND

Rates of sepsis/septicemia hospitalization in the US have risen significantly during recent years. Antibiotic resistance and use may contribute to those rates through various mechanisms, including lack of clearance of resistant infections following antibiotic treatment, with some of those infections subsequently devolving into sepsis. At the same time, there is limited information on the effect of prescribing of certain antibiotics vs. others on the rates of septicemia and sepsis-related hospitalizations and mortality.

METHODS

We used multivariable linear regression to relate state-specific rates of outpatient prescribing overall for oral fluoroquinolones, penicillins, macrolides, and cephalosporins between 2011 and 2012 to state-specific rates of septicemia hospitalization (ICD-9 codes 038.xx present anywhere on a discharge diagnosis) in each of the following age groups of adults: (18-49y, 50-64y, 65-74y, 75-84y, 85 + y) reported to the Healthcare Cost and Utilization Project (HCUP) between 2011 and 2012, adjusting for additional covariates, and random effects associated with the ten US Health and Human Services (HHS) regions.

RESULTS

Increase in the rate of prescribing of oral penicillins by 1 annual dose per 1000 state residents was associated with increases in annual septicemia hospitalization rates of 0.19 (95% CI (0.02,0.37)) per 10,000 persons aged 50-64y, of 0.48(0.12,0.84) per 10,000 persons aged 65-74y, and of 0.81(0.17,1.40) per 10,000 persons aged 74-84y. Increase by 1 in the percent of African Americans among state residents in a given age group was associated with increases in annual septicemia hospitalization rates of 2.3(0.32,4.2) per 10,000 persons aged 75-84y, and of 5.3(1.1,9.5) per 10,000 persons aged over 85y. Average minimal daily temperature was positively associated with septicemia hospitalization rates in persons aged 18-49y, 50-64y, 75-84y and over 85y.

CONCLUSIONS

Our results suggest positive associations between the rates of prescribing for penicillins and the rates of hospitalization with septicemia in US adults aged 50-84y. Further studies are needed to better understand the potential effect of antibiotic replacement in the treatment of various syndromes, including the potential impact of the recent US FDA guidelines on restriction of fluoroquinolone use, as well as the potential effect of changes in the practices for prescribing of penicillins on the rates of sepsis-related hospitalization and mortality.

Chemometrics for resolving spectral data of cephalosporines and tracing their residue in waste water samples

Chemometrics approaches have been used in this work to trace cephalosporins in aquatic system. Principal component regression (PCR), partial least squares (PLS), multivariate curve resolution-alternating least squares (MCR-ALS), and artificial neural networks (ANN) were compared to resolve the severally overlapped spectrum of three selected cephalosporins; cefprozil, cefradine and cefadroxil. The analytical performance of chemometric methods was compared in terms of errors. Artificial neural networks provide good recoveries with lowest error. Satisfactory results were obtained for the proposed chemometric methods whereas ANN showed better analytical performance. The qualitative meaning in MCR-ALS transformation provided very well correlations between the pure and estimated spectra of the three components. This multivariate processing of spectrophotometric data could successfully detect the studied antibiotics in waste water samples and compared favorably to alternative costly chromatographic methods.

Risk factors for community-onset bloodstream infection with extended-spectrum β-lactamase-producing Enterobacteriaceae: national population-based case-control study

OBJECTIVES

The aim was to investigate risk factors for community-onset bloodstream infections with extended-spectrum β-lactamase-producing Enterobacteriaceae (EPE BSI).

METHODS

It is mandatory to report EPE BSI to a national register at the Public Health Agency of Sweden. Using this register, we performed a population-based case-control study from 2007 to 2012 of 945 cases and 9390 controls. Exposure data on comorbidity, hospitalization, in- and outpatient antibiotic consumption and socio-economic status were collected from hospital and health registers.

RESULTS

The overall incidence of EPE BSI was 1.7 per 100 000 person-years. The 30-day mortality was 11.3%. Urological disorders inferred the highest EPE BSI risk, adjusted odds ratio (aOR) 4.32 (95% Confidence Interval (CI) 3.41-5.47), followed by immunological disorders, aOR 3.54 (CI 2.01-6.23), haematological malignancy, aOR 2.77 (CI 1.57-4.87), solid tumours, aOR 2.28 (1.76-2.94) and diabetes, aOR 2.03 (1.58-2.61). Consumption of fluoroquinolones or mostly non-EPE-active antibiotics with selective Gram-negative spectrum of activity within the previous 3 months was associated with EPE BSI, aORs 5.52 (CI 2.8-11.0) and 3.8, CI 1.9-7.7) respectively. There was a dose-response relationship in EPE BSI risk with increasing number of consecutive regimens. Antibiotic consumption >3 months before EPE BSI was not associated with increased risk. Higher age, malignancies and education ≤12 years (aORs >2) were associated with increased 30-day mortality.

CONCLUSIONS

Targeted interventions should be directed towards improving care for patients with immunosuppression, urological disorders and subjects with lower socio-economic status. Antibiotic stewardship should focus on reduction of fluoroquinolones.