Dose regimen optimization of cephalothin for surgical prophylaxis against Staphylococcus aureus and coagulase negative staphylococci in dogs by pharmacokinetic/pharmacodynamic modeling.

First generation cephalosporins such cephalothin of cefazolin are indicated for antimicrobial prophylaxis for clean and clean contaminated surgical procedures because its antimicrobial spectrum, relative low toxicity and cost. Anesthesia and surgery could alter the pharmacokinetic behavior of different drugs administered perioperative by many mechanisms that affect distribution, metabolism or excretion processes. Intravenous administration of the antimicrobial within 30 and 60 min before incision is recommended in order to reach therapeutic serum and tissue concentrations and redosing is recommended if the duration of the procedure exceeds two half-life of the antimicrobial. To the author's knowledge there are no pharmacokinetic studies of cephalothin in dogs under anesthesia/surgery conditions. The aim of this study was (1) to evaluate the pharmacokinetics of cephalothin in anesthetized dogs undergoing ovariohysterectomy by a nonlinear mixed-effects model and to determine the effect of anesthesia/surgery and other individual covariates on its pharmacokinetic behavior; (2) to determine the MIC and conduct a pharmacodynamic modeling of time kill curves assay of cephalothin against isolates of Staphylococcus spp. isolated from the skin of dogs; (3) to conduct a PK/PD analysis by integration of the obtained nonlinear mixed-effects models in order to evaluate the antimicrobial effect of changing concentrations on simulated bacterial count; and (4) to determine the PK/PD endpoints and PK/PDco values in order to predict the optimal dose regimen of cephalothin for antimicrobial prophylaxis in dogs. Anesthesia/surgery significantly reduced cephalothin clearance by 18.78%. Based on the results of this study, a cephalothin dose regimen of 25 mg/kg q6h by intravenous administration showed to be effective against Staphylococcus spp. isolates with MIC values ≤2 µg/mL and could be recommended for antimicrobial prophylaxis for clean surgery in healthy dogs.

Globally Vibrio cholera antibiotics resistance to RNA and DNA effective antibiotics: A systematic review and meta-analysis.

BACKGROUND: Vibrio cholera (V. cholera) is a facultative pathogen that colonizes the small intestine and produces cholerae toxin as the primary virulence factor that causes cholera and fatal diarrhea in humans. In recent decades, V. cholera has emerged as a notorious multidrug-resistant enteric pathogen. This meta-analysis estimated the pooled proportion of V. cholera antimicrobial resistance against RNA and DNA effective antibiotics. METHOD: A systematic search was performed for relevant literature until 05 June 2021 in PubMed, Scopus, Embase, and Web of Science databases. Freeman-Tukey double arcsine transformation was performed to estimate weighted pooled resistance (WPR). RESULTS: The meta-analysis were included 164 articles. The WPR of V. cholera were as follows 76% [67,84] to furazolidone, 65% [29,94] to nitrofurantoin, 55% [44,66] to nalidixic acid, 10% [2,23] to rifampicin, 4%(0, 12) to novobiocin, 4% [2,6] to norfloxacin, 3% [1,4] to ciprofloxacin, 1%(0, 3) to sparofloxacin, 0%(0, 3) to levofloxacin, 0%(0, 2) to ofloxacin, 0%(0, 0) to gatifloxacin. CONCLUSION: V. cholera is a severe problem in Asia and Africa, especially in South Asian countries. The resistance patterns are various in geographical regions. novobiocin 0% (0, 0), and ofloxacin 0% (0, 1) in Africa, gatifloxacin 0% (0, 0), and levofloxacin 0% (0, 6) in Asia and ciprofloxacin 0% (0, 2) in North America are most effective antibiotis. The resistance rate to furazolidone, nalidixic acid, nitrofurantoin, and cephalothin has increased over the years. Monitoring antibiotic resistance and prescribing an appropriate antibiotic is vital to control resistance.

Priming with biocides: A pathway to antibiotic resistance?

AIMS: To investigate the priming effects of sub-inhibitory concentrations of biocides on antibiotic resistance in bacteria. METHODS AND RESULTS: Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were exposed to sub-inhibitory concentrations of biocides via a gradient plate method. Minimum inhibitory concentration (MIC) and antibiotic susceptibility were determined, and efflux pump inhibitors (thioridazine and chlorpromazine) were used to investigate antibiotic resistance mechanism(s). Escherichia coli displayed a twofold increase in MIC (32-64 mg l-1 ) to H2 O2 which was stable after 15 passages, but lost after 6 weeks, and P. aeruginosa displayed a twofold increase in MIC (64-128 mg l-1 ) to BZK which was also stable for 15 passages. There were no other tolerances observed to biocides in E. coli, P. aeruginosa or S. aureus; however, stable cross-resistance to antibiotics was observed in the absence of a stable increased tolerance to biocides. Sixfold increases in MIC to cephalothin and fourfold to ceftriaxone and ampicillin were observed in hydrogen peroxide primed E. coli. Chlorhexidine primed S. aureus showed a fourfold increase in MIC to oxacillin, and glutaraldehyde-primed P. aeruginosa showed fourfold (sulphatriad) and eightfold (ciprofloxacin) increases in MIC. Thioridazine increased the susceptibility of E. coli to cephalothin and cefoxitin by fourfold and twofold, respectively, and both thioridazine and chlorpromazine increased the susceptibility S. aureus to oxacillin by eightfold and fourfold, respectively. CONCLUSIONS: These findings demonstrate that sub-inhibitory concentrations of biocides can prime bacteria to become resistant to antibiotics even in the absence of stable biocide tolerance and suggests activation of efflux mechanisms may be a contributory factor. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates the effects of low-level exposure of biocides (priming) on antibiotic resistance even in the absence of obvious increased biocidal tolerance.

KPC-2 ß-lactamase enables carbapenem antibiotic resistance through fast deacylation of the covalent intermediate.

Serine active-site ß-lactamases hydrolyze ß-lactam antibiotics through the formation of a covalent acyl-enzyme intermediate followed by deacylation via an activated water molecule. Carbapenem antibiotics are poorly hydrolyzed by most ß-lactamases owing to slow hydrolysis of the acyl-enzyme intermediate. However, the emergence of the KPC-2 carbapenemase has resulted in widespread resistance to these drugs, suggesting it operates more efficiently. Here, we investigated the unusual features of KPC-2 that enable this resistance. We show that KPC-2 has a 20,000-fold increased deacylation rate compared with the common TEM-1 ß-lactamase. Furthermore, kinetic analysis of active site alanine mutants indicates that carbapenem hydrolysis is a concerted effort involving multiple residues. Substitution of Asn170 greatly decreases the deacylation rate, but this residue is conserved in both KPC-2 and non-carbapenemase ß-lactamases, suggesting it promotes carbapenem hydrolysis only in the context of KPC-2. X-ray structure determination of the N170A enzyme in complex with hydrolyzed imipenem suggests Asn170 may prevent the inactivation of the deacylating water by the 6α-hydroxyethyl substituent of carbapenems. In addition, the Thr235 residue, which interacts with the C3 carboxylate of carbapenems, also contributes strongly to the deacylation reaction. In contrast, mutation of the Arg220 and Thr237 residues decreases the acylation rate and, paradoxically, improves binding affinity for carbapenems. Thus, the role of these residues may be ground state destabilization of the enzyme-substrate complex or, alternatively, to ensure proper alignment of the substrate with key catalytic residues to facilitate acylation. These findings suggest modifications of the carbapenem scaffold to avoid hydrolysis by KPC-2 ß-lactamase.

Cronobacter spp. isolated from aquatic products in China: Incidence, antibiotic resistance, molecular characteristic and CRISPR diversity.

Cronobacter species (Cronobacter spp.) are important foodborne pathogens that can infect and cause serious life-threatening diseases in infants and immunocompromised elderly. This study aimed to acquire data on Cronobacter spp. contamination of aquatic products in China from 2011 to 2016. In total, 800 aquatic products were tested, and the overall contamination rate for Cronobacter spp. was 3.9% (31/800). The average contamination level of the positive samples was 2.05 MPN/g. Four species and nine serotypes were identified among 33 isolates, of which the C. sakazakii serogroup O1 (n = 9) was the primary serotype. The majority of Cronobacter spp. strains harbored highest resistance against cephalothin (84.8%), followed by tetracycline (6.1%), trimethoprim/sulfameth-oxazole (3.0%) and chloramphenicol (3.0%). Two isolates were resistant to three antibiotics. In total, 26 sequence types and 33 CRISPR types (including 6 new STs and 26 new CTs) were identified, which indicates the extremely high diversity of Cronobacter spp. in aquatic products. Pathogenic C. sakazakii ST4, ST1, and C. malonaticus ST7 were also observed. Overall, this large-scale study revealed the relatively low prevalence and high genetic diversity of Cronobacter spp. in aquatic products in China, and the findings provide valuable information that can guide the establishment of effective measures for the control and precaution of Cronobacter spp. in aquatic products during production processes.

Prevalence of virulence and antimicrobial resistance genes in Aeromonas species isolated from marketed cockles (Tegillarca granosa) in Korea.

This study aimed to examine incidence, virulence and antimicrobial properties in Aeromonas spp. isolated from cockles (Tegillarca granosa) in Korea. Firstly, genomic DNA was extracted from 32 Aeromonas spp. isolates, and PCR screening for virulence, antimicrobial resistance genes was carried out. The disk diffusion assay was used to examine antimicrobial susceptibility. Aeromonas spp. isolates comprised, A. hydrophila (n = 8), A. veronii (n = 15), A. media (n = 2), A. salmonicida (n = 2), A. allosaccharophila (n = 1), A. bestiarum (n = 1), A. culicicola (n = 1), A. enteropelogenes (n = 1) and A. rivipollensis (n = 1). High prevalence of virulence-related genes reported as; act (69%), alt (47%), ast (41%), aerA (56%), lip (50%), ahyB (47%), ser (28%), fla (66%), gcat (44%), ascV (50%) and hlyA (72%). All isolates were multidrug resistant, while highest resistance level observed for ampicillin (100%), followed by imipenem (81%), rifampicin (78%), cephalothin (72%), piperacillin (47%) and Colistin sulfate (31%). The presence of blaSHV , blaCTX , tetE, aac(6')-Ib, strA-strB, qnrS, qnrB and IntI1 genes were reported in varying combinations. Nevertheless, blaTEM , blaIMP , tetA, tetB, qnrA, qnrB and aphAI-IAB genes and the class1 integron were not detected. The high occurrence of virulence and antimicrobial resistance genes in cockles reveals that it can be a potential health risk source for consumers.

Theaflavin-3,3´-digallate increases the antibacterial activity of ß-lactam antibiotics by inhibiting metallo-ß-lactamase activity.

Metallo-ß-lactamases (MBLs) are some of the best known ß-lactamases produced by common Gram-positive and Gram-negative pathogens and are crucial factors in the rise of bacterial resistance against ß-lactam antibiotics. Although many types of ß-lactamase inhibitors have been successfully developed and used in clinical settings, no MBL inhibitors have been identified to date. Nitrocefin, checkerboard and time-kill assays were used to examine the enzyme behaviour in vitro. Molecular docking calculation, molecular dynamics simulation, calculation of the binding free energy and ligand-residue interaction decomposition were used for mechanistic research. The behaviour of the enzymes in vivo was investigated by a mouse infection experiment. We showed that theaflavin-3,3´-digallate (TFDG), a natural compound lacking antibacterial activities, can inhibit the hydrolysis of MBLs. In the checkerboard and time-kill assays, we observed a synergistic effect of TFDG with ß-lactam antibiotics against methicillin-resistant Staphylococcus aureus BAA1717. Molecular dynamics simulations were used to identify the mechanism of the inhibition of MBLs by TFDG, and we observed that the hydrolysis activity of the MBLs was restricted by the binding of TFDG to Gln242 and Ser369. Furthermore, the combination of TFDG with ß-lactam antibiotics showed effective protection in a mouse Staphylococcus aureus pneumonia model. These findings suggest that TFDG can effectively inhibit the hydrolysis activity of MBLs and enhance the antibacterial activity of ß-lactam antibiotics against pathogens in vitro and in vivo.

Assessment of antibiotic resistance in bacteriophage-insensitive Klebsiella pneumoniae.

This study was design to evaluate the physiological properties of bacteriophage-insensitive Klebsiella pneumoniae (BIKP) mutants in association with the antibiotic cross-resistance, ß-lactamase activity, and gene expression. Klebsiella pneumoniae ATCC 23357(KPWT), ciprofloxacin-induced antibiotic-resistant K. pneumoniae ATCC 23357 (KPCIP), and clinically isolated antibiotic-resistant K. pneumoniae 10263 (KPCLI) were used to isolate BIKP mutants against KPB1, PBKP02, PBKP21, PBKP29, PBKP33, and PBKP35. PBKP35-induced mutants, including bacteriophage-insensitive K. pneumoniae ATCC 23357 (BIKPWT), ciprofloxacin-induced K. pneumoniae ATCC 23357 (BIKPCIP), and clinically isolated antibiotic-resistant K. pneumoniae CCARM 10263 (BIKPCLI). BIKPWT, BIKPCIP, and BIKPCLI were resistant to Klebsiella bacteriophages, KPB1, PBKP02, PBKP21, PBKP29, and PBKP33. The antibiotic cross-resistance to cefotaxime, cephalothin, chloramphenicol, ciprofloxacin, erythromycin, kanamycin, levofloxacin, and nalidixic acid was observed in BIKPWT. The relative expression levels of vagC was increased by more than 8-folds in BIKPWT, corresponding to the increased ß-lactamase activity. The aac(6')-Ib-cr was overexpressed in BIKP mutants, responsible for aminoglycoside and quinolone resistance. The phage-resistant mutants decreased the antibiotic susceptibilities in association with ß-lactamase activity and antibiotic resistance-related gene expression. The results pointed out the cross-resistance of BIKP mutants to antibiotics, which might be considered when applying for the therapeutic use of bacteriophage.

Review for Analytical Methods for the Determination of Sodium Cephalothin.

Infections are the second leading cause of global morbidity and mortality, therefore it is highly important to study the antimicrobial agents such as cephalosporins. Cephalothin, an antimicrobial agent that belongs to the class of cephalosporins, has bactericidal activity and it is widely used in the Brazilian health system. In literature, some analytical methods are found for the identification and quantification of this drug, which are essential for its quality control, which ensures maintaining the product characteristics, therapeutic efficacy and patient's safety. The aim of this article is to review the available information on analytical methods for cephalothin. Thus, this study presents a literature review on cephalothin and the analytical methods developed for the analysis of this drug in official and scientific papers. It is essential to note that most of the developed methods used toxic and hazardous solvents, which makes necessary industries and researchers choose to develop environmental-friendly techniques, which will contribute to the harmonization of science, human, and environmental health.

Characteristics of Escherichia coli Isolated from Bovine Mastitis Exposed to Subminimum Inhibitory Concentrations of Cefalotin or Ceftazidime.

Escherichia coli is a major udder pathogen causing clinical mastitis in dairy cattle and its heat stable endotoxin in powdered infant formula milk is a potential risk factor in neonatal infections. Cephalosporins are frequently used for treatment of mastitis caused by mastitis; however, use of these antimicrobials may induce antimicrobial resistance in E. coli. The objective of this study was to explore the in vitro effect of subminimum inhibitory concentrations (sub-MIC) of cefalotin (CF) and ceftazidime (CAZ) on the morphology, antimicrobial resistance, and endotoxin releasing characteristics of 3 E. coli isolates recovered from bovine clinical mastitis. The parent E. coli isolates, which were susceptible to CF and CAZ, were exposed to CF or CAZ separately at sub-MIC levels to produce 9 generations of induced isolates. Colonies of the CAZ-induced isolates from all 3 parent E. coli were smaller on blood agar and the bacteria became filamentous, whereas the CF-induced isolates did not demonstrate prominent morphological changes. After induction by CF or CAZ, many induced isolates showed resistance to cefoxitin, CAZ, CF, kanamycin, ampicillin, and amoxicillin/clavulanic acid while their parent isolates were susceptible to these antimicrobials. Notably, 5 CAZ-induced isolates from the same parent isolate were found to produce extended-spectrum beta-lactamase (ESBL) though none of the tested ESBL related genes could be detected. All CAZ-induced isolates released more endotoxin with a higher release rate, whereas endotoxin release of CF-induced E. coli isolates was not different from parent isolates. The exposure of cephalosporins at sub-MIC levels induced resistant Escherichia coli. We inferred that cephalosporins, especially CAZ, should be used prudently for treatment of clinical E. coli mastitis.

[Susceptibility to first-generation Cephalosporins in Enterobacteriaceae isolated from urine culture according to CLSI and EUCAST breakpoints]. / Estudio de susceptibilidad a cefalosporinas de primera generación en enterobacterias aisladas de urocultivo, según criterios CLSI y EUCAST.

Currently, the use of cefazolin is recommended to determine the susceptibility to first-generation oral cephalosporins in strains of enterobacteria in uncomplicated UTI. We determined susceptibility differences to oral cephalosporins in urinary strains according to cefazolin or cefalotin breakpoints and the correlation of susceptibility between cefazolin and cefadroxil. We studied 52 strains with cefalotin and cefazolin by disk-diffusion and MIC (Kirby-Bauer and Vitek XL) and a subgroup by disk-diffusion for cefadroxil. Agreement among different methods was 100% for K. pneumoniae and Proteus spp. In Escherichia coli, agreement for Vitek and disk-diffusion were 0 and 50% respectively. Susceptibility to first generation cephalosporins in E. coli should be determined with cefazolin. Agreement between cefazolin and cefadroxil suggests that cefazolin could also predict the susceptibility of cefadroxil.

Escherichia coli OxyS RNA triggers cephalothin resistance by modulating the expression of CRP-associated genes.

Antibiotics have been one of the most successful forms of therapy in medicine. However, the efficiency of antibiotics is compromised by the emergence of antibiotic-resistant pathogens. To reduce antibiotic resistance, complete understanding of bacterial tactics to defend themselves against antibiotics is necessary. Small-noncoding RNAs (sRNAs) modulate gene expression by base-pairing with multiple target mRNAs. Cellular levels of Hfq-dependent sRNAs influence antibiotic resistance by modulating expression of specific target genes; therefore, such sRNAs could be a good tool to identify target mRNAs that modulate antibiotic susceptibility and may themselves be used as druggable molecules. Here, we report the identification of genes and pathways associated with OxyS RNA-mediated cephalothin resistance using phenotypic and expression analyses of OxyS-regulated genes identified by RNA-seq, literature mining, or predictions. From our studies we found that the differential expression of 27 OxyS-regulated genes was involved in cephalothin susceptibility. Among them, 17 gene knockouts showed resistance to the drug and nine from them is associated with cAMP receptor protein (CRP), a transcriptional dual regulator in E. coli. Moreover, levels of OxyS and OxyS-modulated genes (cycA and cysH) were also altered in multidrug-resistant (MDR) E. coli strains. Together, our data suggest that OxyS extensively modulates gene expression in multiple pathways to develop cephalothin resistance. In addition, OxyS and its regulated target genes, either individually or in combination, could be used as molecular markers and targets for the identification and eradication of cephalothin-resistant strains.

Trend and Pattern of Antimicrobial Resistance in Molluscan Vibrio Species Sourced to Canadian Estuaries.

The emergence of antimicrobial resistance (AMR) in foodborne bacteria is a growing concern worldwide. AMR surveillance is a key element in understanding the implications resulting from the use of antibiotics for therapeutic as well as prophylactic needs. The emergence and spread of AMR in foodborne human pathogens are indirect health hazards. This surveillance study reports the trend and pattern of AMR detected in Vibrio species isolated from molluscs harvested in Canada between 2006 and 2012 against 19 commonly used antibiotics. Five common antibiotics, ampicillin, cephalothin, erythromycin, kanamycin, and streptomycin, predominantly contributed to AMR, including multidrug resistance (MDR) in the molluscan Vibrio spp. isolated in 2006. A prospective follow-up analysis of these drugs showed a declining trend in the frequency of MDR/AMR Vibrio spp. in subsequent years until 2012. The observed decline appears to have been influenced by the specific downturn in resistance to the aminoglycosides, kanamycin, and streptomycin. Frequently observed MDR/AMR Vibrio spp. in seafood is a potential health concern associated with seafood consumption. Our surveillance study provides an indication of the antibiotics that challenged the marine bacteria, sourced to Canadian estuaries, during and/or prior to the study period.

Characterization of the AmpC ß-Lactamase from Burkholderia multivorans.

Burkholderia multivorans is a member of the Burkholderia cepacia complex, a group of >20 related species of nosocomial pathogens that commonly infect individuals suffering from cystic fibrosis. ß-Lactam antibiotics are recommended as therapy for infections due to Bmultivorans, which possesses two ß-lactamase genes, blapenA and blaAmpC PenA is a carbapenemase with a substrate profile similar to that of the Klebsiella pneumoniae carbapenemase (KPC); in addition, expression of PenA is inducible by ß-lactams in Bmultivorans Here, we characterize AmpC from Bmultivorans ATCC 17616. AmpC possesses only 38 to 46% protein identity with non-Burkholderia AmpC proteins (e.g., PDC-1 and CMY-2). Among 49 clinical isolates of Bmultivorans, we identified 27 different AmpC variants. Some variants possessed single amino acid substitutions within critical active-site motifs (Ω loop and R2 loop). Purified AmpC1 demonstrated minimal measurable catalytic activity toward ß-lactams (i.e., nitrocefin and cephalothin). Moreover, avibactam was a poor inhibitor of AmpC1 (Kiapp > 600 µM), and acyl-enzyme complex formation with AmpC1 was slow, likely due to lack of productive interactions with active-site residues. Interestingly, immunoblotting using a polyclonal anti-AmpC antibody revealed that protein expression of AmpC1 was inducible in Bmultivorans ATCC 17616 after growth in subinhibitory concentrations of imipenem (1 µg/ml). AmpC is a unique inducible class C cephalosporinase that may play an ancillary role in Bmultivorans compared to PenA, which is the dominant ß-lactamase in Bmultivorans ATCC 17616.

Drug Clearance from Cerebrospinal Fluid Mediated by Organic Anion Transporters 1 (Slc22a6) and 3 (Slc22a8) at Arachnoid Membrane of Rats.

Although arachnoid mater epithelial cells form the blood-arachnoid barrier (BAB), acting as a blood-CSF interface, it has been generally considered that the BAB is impermeable to water-soluble substances and plays a largely passive role. Here, we aimed to clarify the function of transporters at the BAB in regulating CSF clearance of water-soluble organic anion drugs based on quantitative targeted absolute proteomics (QTAP) and in vivo analyses. Protein expression levels of 61 molecules, including 19 ATP-binding-cassette (ABC) transporters and 32 solute-carrier (SLC) transporters, were measured in plasma membrane fraction of rat leptomeninges using QTAP. Thirty-three proteins were detected; others were under the quantification limits. Expression levels of multidrug resistance protein 1 (Mdr1a/P-gp/Abcb1a) and breast cancer resistance protein (Bcrp/Abcg2) were 16.6 and 3.27 fmol/µg protein (51.9- and 9.82-fold greater than in choroid plexus, respectively). Among those organic anion transporters detected only at leptomeninges, not choroid plexus, organic anion transporter 1 (oat1/Slc22a6) showed the greatest expression (2.73 fmol/µg protein). On the other hand, the protein expression level of oat3 at leptomeninges was 6.65 fmol/µg protein, and the difference from choroid plexus was within two-fold. To investigate oat1's role, we injected para-aminohippuric acid (PAH) with or without oat1 inhibitors into cisterna magna (to minimize the contribution of choroid plexus function) of rats. A bulk flow marker, FITC-inulin, was not taken up from CSF up to 15 min, whereas uptake clearance of PAH was 26.5 µL/min. PAH uptake was completely blocked by 3 mM cephalothin (inhibits both oat1 and oat3), while 17% of PAH uptake was inhibited by 0.2 mM cephalothin (selectively inhibits oat3). These results indicate that oat1 and oat3 at the BAB provide a distinct clearance pathway of organic anion drugs from CSF independently of choroid plexus.

Prevalence and Antibiotic Resistance Profiles of Campylobacter jejuni Isolated from Poultry Meat and Related Samples at Retail Shops in Northern India.

Campylobacteriosis is the common gastrointestinal disease worldwide. However, in many parts of the world, including India, the impact of campylobacteriosis is less commonly investigated. This study aimed to determine the prevalence and antibiotic susceptibility profiles of Campylobacter jejuni in raw poultry meat and poultry-related samples at retail shops in a region of Northern India. A total of 400 samples of chicken meat (150), chicken intestine (150), feathers (50), and chopping boards and knives (50) samples were screened for the presence of C. jejuni by selective enrichment culture followed by selective plating on mCCDA and also by polymerase chain reaction (PCR) after selective enrichment. The highest prevalence of Campylobacter contamination (38.6%) was observed in chicken meat followed by chicken intestine (24.0%). C. jejuni was detected in 14.0% of chopping boards, knives, and feather samples by culturing method. The hipO gene based PCR detection yielded 36.0% C. jejuni from chicken meat samples; in other samples, however, the prevalence of C. jejuni was observed similar to that of cultural method. The antibiotic susceptibility profiles confirmed drug resistance among 97% of C. jejuni isolates, with 84.1% of C. jejuni isolates resistant to co-trimoxazole followed by cephalothin (81.1%) and tetracycline (59.4%). Low incidence of resistance (6.9-8.9%) was observed against nalidixic acid, ciprofloxacin, erythromycin, gentamicin, and azithromycin. Resistance to multiple drugs (≥4) was recorded in 31.6% of the strains. The findings of this study demonstrated high prevalence of drug-resistant C. jejuni in raw chicken meat and intestinal isolates. The high occurrence of C. jejuni in chicken meat might be due to cross contamination as a result of slaughtering and poor hygienic conditions. Implementation of monitoring/surveillance programs to monitor the prevalence of multidrug-resistant Campylobacter spp. in food production animals, particularly, poultry in semiurban regions, as well as main cities in India, is highly required for better public health protection.

Estudio de susceptibilidad a cefalosporinas de primera generación en enterobacterias aisladas de urocultivo, según criterios CLSI y EUCAST / Susceptibility to first-generation Cephalosporins in Enterobacteriaceae isolated from urine culture according to CLSI and EUCAST breakpoints

Resumen Actualmente se recomienda el uso de cefazolina para determinar la susceptibilidad a cefalosporinas orales de primera generación en cepas de enterobacterias en ITU no complicada. Nuestro objetivo fue establecer la susceptibilidad a cefalosporinas orales en cepas urinarias según puntos de corte para cefalotina o cefazolina y la correlación de susceptibilidad entre cefazolina y cefadroxilo. Se estudió la concordancia entre cefalotina y cefazolina en 52 cepas por método de Kirby-Bauer y Vitek XL. En Escherichia coli fue de 0% para VitekXL y 50% para Kirby-Bauer. La concordancia entre cefazolina y cefadroxilo fue 95,6%. En el laboratorio debiera usarse cefazolina para determinar susceptibilidad a cefalosporinas orales de primera generación. La concordancia entre cefazolina y cefadroxilo sugiere que cefazolina podría predecir susceptibilidad para cefadroxilo.

Currently, the use of cefazolin is recommended to determine the susceptibility to first-generation oral cephalosporins in strains of enterobacteria in uncomplicated UTI. We determined susceptibility differences to oral cephalosporins in urinary strains according to cefazolin or cefalotin breakpoints and the correlation of susceptibility between cefazolin and cefadroxil. We studied 52 strains with cefalotin and cefazolin by disk-diffusion and MIC (Kirby-Bauer and Vitek XL) and a subgroup by disk-diffusion for cefadroxil. Agreement among different methods was 100% for K. pneumoniae and Proteus spp. In Escherichia coli, agreement for Vitek and disk-diffusion were 0 and 50% respectively. Susceptibility to first generation cephalosporins in E. coli should be determined with cefazolin. Agreement between cefazolin and cefadroxil suggests that cefazolin could also predict the susceptibility of cefadroxil.

Phenotypic and Genotypic Characterization of Clinical Enterotoxigenic Escherichia coli Isolates from Shenzhen, China.

BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) is one of the major causes of infectious diarrhea in developing countries. This study aimed to characterize the prevalence and phenotypic and genotypic features of ETEC isolates from Shenzhen, China. METHODS: ETEC isolates were obtained from acute diarrheal patients and evaluated for enterotoxin, classical colonization factors (CFs), serotypes, antimicrobial susceptibility, and multilocus sequencing typing (MLST). RESULTS: A total of 168 (1.3%) ETEC strains were isolated from 13,324 diarrheal outpatients during 2009 and 2014. A vast majority of ETEC-infected patients (82.1%) belonged to the age ranging 20-59 years and only six patients were children aged <5 years. Heat-stable toxin (ST) was most frequently detected (81.5%), followed by heat-labile toxin (LT) (13.1%). One or multiple colonization factors (CFs) were identified in 91 ETEC strains (54.2%). The most frequently detected CF was CS6 (with or without other CFs) (84/91), followed by CS21 (14/91). The most common serotype was O159:H34 (n = 36), followed by O148:H28 (n = 25) and O27:H7 (n = 17). High resistant rate was observed to nalidixic acid (77.4%), cephalothin (41.7%), ampicillin (34.5%), and tetracycline (21.4%). Antimicrobial resistance profiles differed among different serogroups. Sequence type (ST) 10 complex, integrated with connected ST218, ST48, ST4, and ST1312 subgroups, covered 73 (43.5%) isolates. CONCLUSIONS: ETEC isolates in Shenzhen of China appeared highly diverse, yet some isolates belonged to well-defined clonal groups sharing a unique set of virulence factors, serotypes, and MLST sequence types. Facing the challenge of ETEC antigenic diversity and geographic variation, novel molecules and/or classical antigens designed by novel strategies might contribute to ETEC vaccine development.

Ceftriaxone Etest non-susceptible methicillin susceptible Staphylococcus aureus time-kill responses.

We determined the correlation between Etest and BMD MICs with bactericidal activity in MSSA blood isolates. Ceftriaxone was bactericidal in 36% and 9% of isolates exposed to the Etest and BMD MIC, respectively. With the sub-optimal activity of ceftriaxone, the Etest MIC may be a conservative method in identifying clinical utility.

Prevalence, antimicrobial resistance and multiple-locus variable-number tandem-repeat analysis profiles of diarrheagenic Escherichia coli isolated from different retail foods.

Diarrheagenic E. coli (DEC) isolates were recovered from local retail markets and the Osaka Municipal Central Wholesale Market in Japan. Retail food samples were collected for analysis in Osaka Japan from 2005 to 2008 and consisted of 32 beef, 28 pork, 20 poultry, 136 fish, 66 fruits and vegetables and 51 ready-to-eat (RTE) food samples. A total of 82 DEC strains were recovered from 64 (19%) food samples with the highest prevalence in poultry (100%, 20/20), followed by pork (54%, 15/28), beef (28%, 9/32), fruits and vegetables (12%, 8/66), fish (6.6%, 9/136) and RTE foods (5.9%, 3/51). Most of the strains belonged to E. coli possessing the enteroaggregative E. coli (EAEC) heat-stable enterotoxin 1 (EAST1) gene (EAST1EC; n=62, P<0.0001) and enteropathogenic E. coli (EPEC; n=16, P<0.01), whereas only 1 strain belonged to Shiga toxin-producing E. coli (STEC), 1 to EAEC and 2 to enterotoxigenic E. coli (ETEC) strains. Of the 82 DEC isolates, 22 O and 13H serogroups were detected, including some specific serogroups (O91, O103, O115, O119, O126, and O157) which have been associated with human diarrheal infections. Phylogenetic group A and B1 were predominant among the DEC isolates. Antimicrobial resistance to tetracycline was most common (49%), followed by nalidixic acid (28%), ampicillin (24%), sulfamethoxazole/trimethoprim (20%), and cephalothin (18%). All isolates were susceptible to aztreonam. Of the resistant strains, 44% (22/50) demonstrated resistance to >3 antimicrobial agents. Isolates resistant to >5 antimicrobials were only found in the meat samples, while isolates from the fruits and vegetables as well as RTE foods showed resistance to only 1 or 2 antimicrobial agents. Sixty one percent of EAST1EC, 56% of EPEC and all of the EAEC and ETEC were resistant to at least 1 antimicrobial agent. Multiple-locus variable-number tandem repeat analysis (MLVA) was used in this study for genotyping of DEC. The 82 isolates collected for this study showed 77 distinct MLVA profiles located among 3 branches. The Simpson's Index of Diversity (D) was 99.9% at its highest. The high diversity of these food strains would suggest their originating from a variety of sources and environments. In conclusion, retail food samples in Japan were contaminated with DEC; EAST1EC, a putative DEC, were detected at high rates in poultry, pork and beef. Isolates resistant to >3 antimicrobials were found only in raw meat and fish. Food animals may act as the reservoir for multi-resistant bacteria. Due to the finding that nearly 1/3 of EAST1EC strains were resistant to >3 antimicrobials, additional surveillance for EAST1EC should be initiated.