Cefotaxime Research Articles

New Turbidimetric Method for Determination of Cefotaxime Sodium in Pharmaceutical Drugs Using Continuous Flow Injection Manifold Design with CFTS- Vanadium Oxide Sulfate System

The determination of Cefotaxime sodium pure from and pharmaceuticals (tablets) by continuous flow injection scatter light has been created using a new, simple, rapid, and sensitive approach. Using a handmade ISNAG-FIuorimeter, the technique was predicated on the interaction of Cefotaxime sodium with vanadium oxide sulfate to produce a precipitate. The optimal value had a linear dynamic range of 0.01-20 mmoI/L for the instrument response to Cefotaxime sodium concentration, while the L.O.D was 0.334 g /sample from the stepwise dilution for the lowest concentration in the calibration graph's scatter plot range. For the scatter plot range and the linear dynamic range, the correlation coefficient (r) was 0.9769 and 0.9978, respectively, while percentage linearity (R2% percent) was 95.43 percent and 99.56 percent, respectively. With a concentration of 2.5 mmol/L, the RSD percent for repeatability (n=8) was lower than 0.23% percent for the determination of cefotaxime sodium. The proposed method was effectively used to determine the concentration of cefotaxime sodium in pharmaceutical tablets. The newly developed technique was compared with the conventional methods of analysis, i.e., Turbidemtric method and UV-spectrophotometer method, utilizing the usual addition method and paired t-test. The computed t-value at 95 percent confidence interval from the established approach revealed that there was no significant difference between the quoted figures of any individual firm.

Study of the polymerized impurities in cefotaxime sodium and cefepime by applying various chromatographic modes coupled with ion trap/time-of-flight mass spectrometry

Polymerized impurities in β-lactam antibiotics can induce allergic reaction, which seriously threaten the health of patients. In order to study the polymerized impurities in cefotaxime sodium and cefepime, a HPSEC method with TSK-gel G2000SWxl column and a RP-HPLC method with C18 column were established to replace the classical gel filtration chromatography with Sephadex G-10 gel as stationary phase. Two-dimensional (2D) liquid chromatography was employed to further investigate the HPSEC and RP-HPLC method and ion trap/time-of-flight mass spectrometry was applied to characterize the structures of polymerized impurities eluted from the two methods. The structures of the polymerized impurities in cefotaxime sodium and cefepime were deduced based on the MSn data, six of which were previously unknown. The corresponding relationship of impurities between the two methods was established, and the specificity of the two methods was compared. The results showed that the polymerized impurities in cefotaxime sodium and cefepime were co-eluted with other small molecular weight impurities with high polarity in HPSEC, leading to a poor specificity. The newly established RP-HPLC methods could effectively separate and detect polymerized impurities and were suitable for the quality control in daily analysis.

Sodium Cefotaxime–Potato Starch Conjugate as a Potential System for Antibacterial Drug Delivery

Sodium Cefotaxime–Potato Starch Conjugate as a Potential System for Antibacterial Drug Delivery

Drug resistance characteristics of Diarrheagenic Escherichia coli isolated from patients with diarrhea in Shunyi district of Beijing, 2013–2019

Objective To study the drug resistance characteristics of Diarrheagenic Escherichia coli (DEC) isolated from patients with diarrhea in two sentinel hospitals in Shunyi district of Beijing during 2013—2019. Method Stool samples of diarrhea patients were collected in the two sentinel hospitals during this period. Isolation, bacterial identification and PCR typing were conducted for DEC strains. Antimicrobial susceptibility tests were carried out using micro broth method to analyze the drug resistance characteristics of the isolated strains, including resistance rate, non-sensitive rate, multi-drug resistance rate and drug resistance spectrum. Result The detection rate of DEC in diarrhea patients was 9.53% (232/2434). The proportions of Enterotoxic Escherichia coli (ETEC), Enteropathogenic Escherichia coli (EPEC), and Enteroaggregative Escherichia coli (EAEC) were 56.47% (131/232), 27.16% (63/232) and 16.38% (38/232), respectively. The multi-drug resistance rates of DEC with 90 drug resistance spectrum, ETEC with 36 drug resistance spectrum, EPEC with 42 drug resistance spectrum, and EAEC with 23 drug resistance spectrum were 33.19% (77/232), 17.56% (23/131), 58.73% (37/63), 44.74% (17/38), respectively. Antibacterial drugs with resistance rate ≥30% included nudicacid (NAL) and ampicillin (AMP) for ETEC; AMP, tetracycline (TET), sulfamethoxazole tablets (SXT), sulfamethoxazole (Sul), NAL for EPEC; NAL, AMP, SXT, Sul, TET for EAEC. A comparison of the differences in the antimicrobial susceptibility tests during 2013—2016 and during 2017—2019 found that the resistance of ETEC to AMP, cefazolin (CFZ), TET, cefepime (FEP), aztreonam (AZM), and ampicillin/sulbactam (AMS) increased, while the resistance to Sul decreased; the resistance of EPEC to gentamicin (GEN) decreased; the resistance of EAEC to cefotaxime (CTX), GEN, and doxycycline (DOX) decreased. Conclusion Among the diarrhea cases in Shunyi, the intensity of DEC spread was high, and the spread and the drug resistances of ETEC, EPEC and EAEC had unique characteristics. The drug resistance was serious, to which close attention should be paid.

Rapid detection of bacteria that produce extended-spectrum β-lactamase by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Proper use of antibacterial agents is necessary to prevent the spread of drug-resistant bacteria. To support clinicians, laboratories need to rapidly determine bacterial drug susceptibility/resistance. We have established a method to distinguish extended-spectrum β-lactamase (ESBL)-producing clinical isolates by capturing structural changes in β-lactam antibiotics using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). Clinical isolates of Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis, classified into ESBL-producing strains and sensitive strains based on the presence or absence of a CTX-M-type gene, were used. Test bacteria were cultured aerobically in solid-phase wells of Eiken DPD1 dry plates at 35°C for 15 min or 30 min with the antibiotics cefotaxime (CTX), cefpodoxime (CPDX) or piperacillin (PIPC). Culture supernatants were then used for analysis with a MALDI Biotyper. Signals derived from non-hydrolyzed products of antibiotics were observed in all strains. In the case of ESBL-producing strains, signals derived from the hydrolysis products of antibiotics were also observed. Since the ratio of signal intensity derived from hydrolysis products divided by the total signal intensity detected was ≥11% for CTX and ≥6% for CPDX and PIPC, all strains were determined to be ESBL-producing bacteria. The short incubation time of 15 min suggests that this method can identify ESBL-producing strains much more rapidly than conventional methods.

Molecular characterization of Streptococcus and Enterococcus species isolated from broiler chickens

Streptococcus and Enterococcus infections in chickens may result in significant negative effect on economy. In the current study, the prevalence of Streptococcus and Enterococcus species was planned in different broiler chickens farms in Beni-Suef Governorate. A total of 272 samples were collected from lesions (septicemic organs, enlarged organs, necrotic focci) of the affected organs including heart, lung, liver and kidney of diseased broiler chickens and freshly dead ones. Out of 272 samples a total of 49 isolates were recovered with incidence of 18% including 26Streptococcus spp. (53.1%) and 21 Enterococcus spp. (42.8%) meanwhile 2 isolates (4.1%) were unidentified. Streptococcus isolates were identified as S.gallinaceous (24.5%), S. dysgalactiae (16.3%) and S. durans (12.2%). Meanwhile all Enterococcus isolates were identified as E. faecalis. The in-vitro antibiotic sensitivity testing showed that all isolates were highly sensitive to amoxicillin (77.6%), sulfamethoxazole-trimethoprim (73.5%) and amoxicillin-clavulanic acid (65.3%). Meanwhile, all isolates were resistant to cephalexin, cefotaxime sodium, cefipime, cefotriaxone, tetracycline, kanamycin and apramycin while 87.8 and 63.2% of isolates showed resistance aganist gentamicin and enrofloxacin, respectively. Moreover, multidrug resistant were detected in all isolates. Polymerase chain reaction (PCR) was applied to identify 4 resistance-associated genes including (tetO, aac(6')aph(2''), blaZ and Pbp 1A) as well as 6 virulence-associated genes including (cylE, brp A, hyl, cylA, asa1 and gelE). The results indicated that tetO, aac(6')aph(2''), blaZ, Pbp 1A, cylE, brp A, cylA and asa1 genes were recovered from all the tested isolates (100%). Meanwhile, none of streptococcus isolates had hly gene also, gelE gene not detected in enterococcus isolates.

Genotypic and phenotypic characteristics of Streptococcus pneumoniae from community-acquired pneumonia patients and healthy asymptomatic participants in Sichuan province, China

BackgroundStreptococcus pneumoniae (S. pneumoniae) is the common cause of community-acquired pneumonia (CAP) and is also found in the upper respiratory tract of healthy people. Hence, the study aimed to compare the serotypes, virulence/pili genes, and antibiotic susceptibility of S. pneumoniae from healthy asymptomatic participants and CAP patients.MethodsStreptococcus pneumoniae were retrospectively collected from health asymptomatic participants and CAP patients in Sichuan, China. The serotypes were tested by multiplex polymerase chain reaction (PCR) or Quellung reaction. Antibiotic susceptibility testing was performed using the broth microdilution method. The molecular epidemiology of S. pneumoniae was analyzed by multilocus sequence typing (MLST). Additionally, the presence of virulence/pili genes were detected using PCR.ResultsA total of 83 pneumococcal isolates were collected in the current study. Of these, 52 and 31 isolates were from healthy asymptomatic participants and CAP patients, respectively. Most of S. pneumoniae were resistant to erythromycin (ERY), clindamycin (CLI), tetracycline (TET) and trimethoprim-sulfamethoxazole (SXT). 90.4% isolates were classified as multidrug resistant (MDR). The predominant serotypes were 3, 19F and 19A in the CAP carriers, whereas 3, 6 and 19F were the main serotypes among the asymptomatic carriers. The overall coverage rates of pneumococcal conjugate vaccine (PCV) 10 and PCV13 serotypes were 34.9% and 66.3%, respectively. The predominant sequence types (STs) were ST271, ST320, and ST3397. There were significant differences in some resistance and virulence characteristics between CAP patients and asymptomatic carriers. Additionally, clonal complex (CC) 271 strains had higher percentage in resistance to cefuroxime (CXM) and cefotaxime (CEF), meropenem (MER) and cefepime (CFP), which mainly carried the rlrA and sipA genes.ConclusionsHigh coverage rate of PCV13 and high prevalence of MDR indicated the necessity to expand immunization with PCV13 and rationally use the antibiotics in Sichuan, China. Importantly, long-term surveillance should be conducted to assess effectiveness brought by vaccines. Our findings may supply new guidance for developing new pneumococcal vaccines.

Enhanced photocatalytic antibacterial and degradation performance by p-n-p type CoFe2O4/CoFe2S4/MgBi2O6 photocatalyst under visible light irradiation

Although advanced photocatalysts have been developed for water disinfection, photocatalytic activity is still limited owing to the difficulty of recycling nanoparticles and the high recombination rate of photogenerated electron-hole pairs. In this paper, efficient and recyclable CoFe2O4/CoFe2S4/MgBi2O6 (CFO/CFS/MBO) magnetic fibers (MNFs) photocatalyst with p-n-p type heterojunction are obtained by a simple hydrothermal method. As expected, when the optimal concentration of CFO/CFS/MBO was 0.5 mg/mL, the antibacterial rate reached 99.8% toward Methicillin-resistant Staphylococcus aureus (MRSA) after 60 min visible light irradiation. The optimal sample 30% CFO/CFS/MBO composite can degrade 82.7% Cefotaxime sodium (CTX) in 60 min. The mechanism was shown to be the severe damage of bacterial cell membranes and decomposition of antibiotic molecules caused by ROS generated by CFO/CFS/MBO photocatalyst under visible light irradiation. Due to the p-n-p heterojunction structural characteristics and abundant oxygen vacancies, CFO/CFS/MBO possessed a stronger absorption capacity of visible light and enhanced photo-generated carrier separation efficiency, which has a remarkably positive impact on the ability of photo-generated ROS. PL and EIS revealed the improvement of the separation efficiency of photogenerated carriers. LC-MS analysis, EPR and scavenger experiments verified the intermediate product, active species and photodegradation pathway in the photocatalytic process. Such recyclable and highly efficient CFO/CFS/MBO MNFs photocatalysts have promising applications in wastewater treatment.

Efficacy of Etimicin Sulfate Combined with Cefotaxime Sodium in the Treatment of Patients with Septic Shock and Effect on Serum Inflammatory Factor Levels and Immune Function.

Objective To explore the effect of etimicin sulfate combined with cefotaxime sodium and cefotaxime sodium alone in the treatment of patients with septic shock and the effect on serum inflammatory factor levels and immune function. Methods Total of 95 patients with septic shock who were treated in our hospital from March 2018 to July 2020 were collected as the subjects of this study. Among them, 44 patients who received cefotaxime sodium treatment and were included in the control group, and 51 patients who received etimicin sulfate combined with cefotaxime sodium treatment were included in the research group. The levels of serum IL-6 (interleukin-6), PCT (procalcitonin), TNF-α (tumor necrosis factor-α), CD3+ (cluster of differentiation 3+), CD4+, CD4+/CD8+, FIB (fibrinogen), and PT (prothrombin time), APTT (activated partial thromboplastin time) time before and after treatment, and the treatment effects, mechanical ventilation time, hospitalization time, and incidence of adverse reactions between the two groups were compared. Results The total effective rate of treatment in the research group (90.20%) was higher than the control group (72.73%) (p < 0.05). After treatment, the serum levels of IL-6, PCT, and TNF-α, FIB, CD3+, CD4+, CD4+/CD8+, and PT and APTT time in the two groups of patients have improved significantly (p < 0.05). Compared with the control group, the research group's IL-6, PCT, TNF-α levels, PT, and APTT decreased more, and FIB, CD3+, CD4+, and CD4+/CD8+ levels increased more (p < 0.05). The mechanical ventilation time and hospital stay of the research group were significantly shorter than the control group (p < 0.05). There was no significant difference between the total incidence of adverse reactions in the research group (15.69%) and the control group (9.09%) (p > 0.05). Conclusion Compared with cefotaxime sodium alone, the treatment of etimicin sulfate combined with cefotaxime sodium is more effective in improving the coagulation function and cellular immune function of patients with septic shock, reducing the level of serum inflammatory factors, and having higher clinical treatment effective.

Antibiotic Breakdown by Susceptible Bacteria Enhances the Establishment of β-Lactam Resistant Mutants.

For a better understanding of the evolution of antibiotic resistance, it is imperative to study the factors that determine the initial establishment of mutant resistance alleles. In addition to the antibiotic concentration, the establishment of resistance alleles may be affected by interactions with the surrounding susceptible cells from which they derive, for instance via the release of nutrients or removal of the antibiotic. Here, we investigate the effects of social interactions with surrounding susceptible cells on the establishment of Escherichia coli mutants with increasing β-lactamase activity (i.e., the capacity to hydrolyze β-lactam antibiotics) from single cells under the exposure of the antibiotic cefotaxime (CTX) on agar plates. We find that relatively susceptible cells, expressing a β-lactamase with very low antibiotic-hydrolyzing activity, increase the probability of mutant cells to survive and outgrow into colonies due to the active breakdown of the antibiotic. However, the rate of breakdown by the susceptible strain is much higher than expected based on its low enzymatic activity. A detailed theoretical model suggests that this observation may be explained by cell filamentation causing delayed lysis. While susceptible cells may hamper the spread of higher-resistant β-lactamase mutants at relatively high frequencies, our findings show that they promote their initial establishment.

Effect of carbon nitride synthesized by different modification strategies on the performance of carbon nitride/PVDF photocatalytic composite membranes

Carbon nitride (CN)/polyvinylidene fluoride (PVDF) photocatalytic composite membrane (PCM) is considered as a promising candidate to improve the anti-fouling characteristic of conventional PVDF membrane and overcome the difficulty encountered during recovery of powder catalyst simultaneously. However, the effects of differently-modified CN on PCM and its mechanism are still unclear. In this study, bulk-CN (BCN), carbon defects CN (CCN), nitrogen defect CN (DCN), mesoporous CN (MCN), and nitrogen-rich CN (NCN) were incorporated into PVDF by phase inversion method. The influence of changes in the physical and chemical properties of CN, including hydrophilic groups, photocatalytic activity, and particle size, on the permeability, anti-fouling characteristic, and photocatalytic self-cleaning activity of CN/PVDF was systematically analyzed. The mechanism of excellent performance of PCM was revealed by experimental test and theoretical calculation. The flux of PCM was significantly improved by increasing the hydrophilic group on modified CN. However, the differences in particle size and interaction between different types of modified CN and PVDF chains endowed the CN/PVDF with different porosity. DCN/PVDF showed high porosity and hydrophilicity, leading to high water flux and rejection rate of 293.6 L (m2 h)−1 and 90.1%, respectively. Compared to pure PVDF, the flux recovery rate of DCN30/PVDF increased by 27.6%, and the irreversible fouling decreased from 36.9% to 9.2%. The modified CN/PVDF showed excellent photocatalytic activity for the removal of cefotaxime (CFX) and E. coli. Owing to the narrow band gap of DCN, large specific surface area, and low photogenerated carrier recombination rate, the CFX removal rate reached 99% in 2 h, and E. coli inactivation achieved 3.7 log within 4 h via DCN30/PVDF.

Isolation and Characterization of Shiga Toxin-Producing Escherichia coli from Retail Beef Samples from Eight Provinces in China.

While Shiga toxin-producing Escherichia coli (STEC) is a major foodborne pathogen worldwide, data on the molecular and phylogenetic properties of STEC isolates from retail beef samples in China remain scant. Fresh retail beef samples (n = 1062) were collected from eight provinces, and STEC isolates were recovered and characterized. PCR data showed that more than 50% of the samples were stx positive, and 82 STEC isolates were recovered from 14.8% (79/535) stx-positive enriched broths. In contrast, all ciprofloxacin resistant isolates (n = 19) and 13 cefotaxime (CTX) resistant isolates were eae positive and belonged to three serotypes: O111:H8, O26:H11, or O157:H7. Point mutations in quinolone resistance-determining regions and plasmid-mediated quinolone resistance determinants were identified in 16 and 20 isolates, respectively. BlaCTX-M and a point mutation (C-42T) in ampC promoter were detected in 15 and 8 of the CTX resistant isolates, respectively. In addition, macrolide resistance gene mphA was identified in eight azithromycin resistant O111:H8 isolates and one O26:H11 isolate. Single nucleotide polymorphism analysis demonstrated that the O26 and O157 isolates had multiple origins, but the O111 isolates were closely related. Taken together, our data demonstrated that several sequence types associated with hemolytic uremic syndrome from the retail beef samples in China had developed into dangerous multidrug resistant pathogens. The resistant phenotype can facilitate their transmission among the farm animals and human beings when there is an antimicrobial selective pressure.

Cefotaxime sodium inhibited melanogenesis in B16F10 cells by cAMP/PKA/CREB pathways

Cefotaxime sodium (CTX) was found to inhibit the activity of mushroom tyrosinase. The present study was conducted to investigate its inhibition of melanogenesis in B16F10 cells. CTX was found to inhibit melanin synthesis in B16F10 cells at a concentrations less than 200 μmol/L with no cytotoxicity. CTX reduced tyrosinase activity in a dose-dependent manner. CTX inhibited melanin formation from the results of the Masson-Fontana melanin staining and transmission electron microscope CTX influenced melanin production by influencing the expression of the proteins MITF, TRP-1, TRP-2 and TYR. Furthermore, CTX could down-regulate the intracellular cAMP/PKA/CREB contents, affecting the expression of MITF, and further down-regulate the expression of TRP-1, TRP-2 and TYR to inhibit melanin. Furthermore, CTX has been shown to inhibit body pigmentation in zebrafish. These results may provide a theoretical foundation for the new application of CTX in the field of medicine.

Highly efficient photoelectrocatalytic degradation of cefotaxime sodium on the MoSe2/TiO2 nanotubes photoanode with abundant oxygen vacancies

Novel multifunctional photoanode on basis of MoSe2 nanoparticles modified TiO2 nanotubes(denoted as MoSe2/TiO2 NTs) were successfully prepared by facile electrochemical methods namely anodization followed by cyclic voltammetry method using titanium foil as substrate. Compared to TiO2 NTs, the MoSe2/TiO2 NTs display excellent photoeletric properties, including more abundant surface oxygen vacancies, enhanced visible-light absorption, improved photocurrent response, reduced fluorescence intensity and decreased charge transfer resistance. These enhancements should be attributed to efficient spatial separation and rapid transfer of photo-induced electrons and holes on the intimate contact interface between MoSe2 nanoparticles and TiO2 NTs. In the photo-electric synergistic catalytic system, the as-prepared MoSe2/TiO2 NTs play double roles as both photoanode and catalyst. Under simulated solar light illumination, the MoSe2/TiO2 NTs photoanode shows superior photoelectrocatalytic activity in the degradation of cefotaxime sodium at low applied bias voltage. Moreover, a possible mechanism of the transfer pathway of photo-induced charge carriers on the MoSe2/TiO2 NTs photoanode is proposed based on the synergistic effect of surface oxygen vacancies and direct Z-scheme heterojunction.

Molecular epidemiology of cefotaxime-resistant but ceftazidime-susceptible Enterobacterales and evaluation of the in vitro bactericidal activity of ceftazidime and cefepime.

Extended-spectrum β-lactamases' (ESBLs) production is the main resistance mechanism to third-generation cephalosporins (TGCs) in gram-negative bacilli. In Argentina, there is a high prevalence of cefotaximase-type ESBLs (CTX-M). For this reason, dissociated resistance phenotype (DRP) displaying a profile of resistance to cefotaxime (CTX) and susceptibility to ceftazidime (CAZ) might be detected. The aims of this study were to determine the prevalence of DRP inEnterobacteralesclinical isolates, to characterize the mechanisms responsible for this phenotype and to evaluate the in vitro behaviour against different antibiotics. Sixty Enterobacteralesresistant to any TGC were studied, and among them, 25% displayed a DRP. The β-lactamases associated with DRP were 5/11 CTX-M-2, 4/11 CTX-M-14, 1/11 CTX-M-15 and 1/11 CMY-2 inE. coli, 2/3 CTX-M-2 and 1/3 CMY-2 inP. mirabilis and 1/1 CTX-M-14 inK. pneumoniae. Furthermore, CTX-M-2 and CTX-M-14 were related with DRP in both wild-type isolates and the corresponding transconjugants. Time-kill experiments showed CAZ bactericidal activity on CTX-M-2-and CTX-M-14-producing strains and bacterial regrowth in those CMY-2 producers. An opposite behaviour was evident when cefepime (FEP) was used. However, CAZ and gentamicin combination showed a synergistic effect against the CMY-2 producers. We concluded thatEnterobacteraleswith DRP responded differently to CAZ or FEP depending on the type of β-lactamase they possess, suggesting that these cephalosporins could be a therapeutic option. Therefore, the characterization of the involved resistance mechanism might contribute to define the appropriate antibiotic treatment.

Effect of Zinc Oxide Nanoparticles on Loaded Antibiotics Against Multidrug-Resistant Acinetobacter spp.

Background: Metal oxide nanoparticles (NPs) have shown promising efficacy for combating bacterial resistance due to their antibacterial properties. This research investigated the effect of zinc oxide NPs (ZnO-NPs) on the antibacterial activity of conventional antibiotics including ciprofloxacin (CIP), cefotaxime (CTX), and colistin (CST) against multidrug-resistant Acinetobacter isolates. Methods: The disc diffusion method was performed to detect the pattern of antibiotic resistance in isolates. The synthesized ZnO-NPs via the solvothermal method were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). Finally, the broth microdilution technique was conducted to demonstrate the antibacterial activity of CIP, CTX, and CST antibiotics with and without a sub-inhibitory concentration of ZnO-NPs. Results: XRD, EDS, and FESEM results confirmed the crystalline structure of ZnO-NPs, and the average size was 100±58.68 nm. All isolates were discovered to be of multidrug-resistant (MDR) type and fully susceptible to CST. The antibacterial activity of CTX and CIP was restored when combined with a sub-inhibitory level of ZnO-NPs (0.25 mg/L), and the highest activity was obtained at the concentrations of 32 µg/mL CTX and 8 µg/ mL CIP. Eventually, ZnO-NPs showed a synergistic effect on the antibacterial properties of CST against MDR Acinetobacter. Conclusions: This research indicated that the combination of ZnO-NPs with some common antibiotics can be considered as a novel strategy for reducing the spread of antibiotic-resistant bacteria.

Molecular Epidemiology of AmpC-Producing Klebsiella Pneumoniae Isolated from Perioperative Patients in a Tertiary Hospital

Background: Extended-spectrum cephalosporin-resistant organisms are the sources of AmpC- type β-lactamase isolates. AmpC-producing Klebsiella pneumoniae isolates are a major challenge in clinics due to their high rate of antibiotic resistance. This study aimed to detect AmpC β-lactamases in K. pneumoniae isolated from hospitalized patients with a surgical history. Materials and Methods: This cross-sectional study was performed on 120 urine catheter samples. After antibiotic susceptibility testing, plasmid-mediated AmpC was detected by double-disc plus combined disc test (DCDT) and three-dimensional extract test (TDET). The genotypic detection of plasmid-mediated AmpC was carried out using multiplex-polymerase chain reaction (PCR). Results: Of 120 samples, 60 (50%) instances of K. pneumoniae were isolated. The highest and lowest resistance rates were related to cefotaxime (CTX) (50%) and ciprofloxacin (CIP) (23.3%), respectively. 18.3% (n: 11) K. pneumoniae showed an AmpC phenotype in DCDT and TDET tests. AmpC genotyping showed that the prevalence of CIT, DHA, EBC, and ACC genotypes were 47.1%, 35.3%, 29.5%, and 23.6%, respectively. MOX and FOX genotypes were not identified in the isolates of interest. Conclusion: AmpC β-lactamase identification tests should be considered a routine microbiology workup for gram-negative microorganisms. Multiplex-PCR can identify the plasmid AmpC genotypes.

Antibiotic resistance in heavy metal resistant non-lactose fermenting Enterobacteriaceae colonies cultured from textile industry effluents

Many of the aquatic pathogenic microflora belong to the non-lactose fermenting (NLF) Enterobacteriaceae and emergence as well as the spread of antibiotic resistance in them is now a serious threat to public health worldwide. Growth of textile industries has heavily flourished acting as hub for the ready-made garments factories in Bangladesh. Textile industry effluents may contain heavy metals and it is not clear whether their disposal is strictly monitored or not and their impact on the aquatic microflora have not been properly investigated and monitored. To assess the impact of heavy metals on the emergence and spread of antibiotic resistance in NLF Enterobacteriaceae, samples were collected from four different locations of drains running down effluents from five (n=5) different textile industries located in Savar, Dhaka, Bangladesh. Total bacterial counts (TBCs), minimal inhibitory concentrations (MICs) of heavy metals, antibiotic susceptibility, binary exposure and plasmid profile experiments were performed. TBCs from day 1 to day 5 revealed that most colony forming units (CFUs) uncountable at 10-6 dilution could be counted at 10-10 dilution. A total of 100 NLF bacterial isolates were categorized as type-1 and type-2 using 4 differential media. The MICs of 100% isolates in both type-1 and type-2 for nickel (Ni), lead (Pb) and chromium (Cr) were 0.6 mM, 0.6 mM and 1.0 mM, respectively. In case of type-1, most (38%) showed resistance to azithromycin (AZM) and least (2%) to cefotaxime (CTX). In case of type-2, most (48%) showed resistance to AZM and least (8%) to CTX. Binary exposure experiments revealed the combined effect of heavy metals and antibiotics. Where in most cases, zone of inhibition increased or remained unchanged. In few cases, zone of inhibition decreased. This finding indicated that the heavy metals typically exert negative or no effects on antibiotic resistance in the isolates tested. Plasmid profiling of the type-1 and type-2 NLF isolates resistant to both the antibiotics and heavy metals revealed that one of the five type-1 isolates contained very large plasmid (14 Kb) and four of the eight type-2 isolates contained 13 Kb plasmids and two contained 12 Kb plasmids. These findings indicated that these isolates possibly possess the ability to sequester metals before being discharged into the soil and/or water environment. Keywords: Antibiotics, effluents, heavy metals, minimum inhibitory concentration (MIC), resistance.

English

It is crucial to monitor the microbial ambience in heavy metal enriched industrial effluents that generally discharge into the environment. Therefore, the present study aimed to understand the load of heavy metals in multidrug-resistant lactose fermenting microorganisms isolating from textile industry effluents. Samples were collected from five different textile industrial canals. In most of the cases, the colony forming units (CFUs) per plate were uncountable at 10-6 dilution but countable at 10-10 dilution. A total of 100 lactose fermenting (LF) isolates were selected using 4 differential media and tested for the determination of minimum inhibitory concentrations (MICs) of heavy metals and antibiotic susceptibility. For nickel (Ni), the MIC was 0.3 mM for almost 98% isolates. The MIC was 0.5 mM for chromium (Cr) in almost 99% isolates. For lead (Pb), 100% isolates had a MIC of 0.4 mM. The most prevalent (36%) resistance pattern was found for sulfamethoxazole-trimethoprim (SXT) and only 10% isolates showed resistance to cefotaxime (CTX). The combined effect of heavy metals and antibiotics revealed that in most cases, the antibiotic zone of inhibition was increased. Plasmid profiling showed that among 14 selective isolates, high sized (21kb) plasmid was found in 6 isolates. &nbsp; Key words: Antibiotics, effluents, heavy metals, minimum inhibitory concentration (MIC), antimicrobial resistance.

Surveillance of Phenotypic Extended Spectrum Beta-Lactamase Resistance in Blood Isolates at a Hospital in East Trinidad

Background The Centres for Disease Control and Prevention (CDC) and World Health Organization (WHO) list extended spectrum beta-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae as serious threats and priority pathogens. This study identified phenotypic resistance patterns to these pathogens in east Trinidad, West Indies. We also aimed to set up and test a pilot surveillance system aligned to WHO’s Global Antimicrobial Surveillance System (WHO-GLASS). Methods Two key bacterial isolates, Escherichia coli and Klebsiella pneumoniae were used and one specimen, blood, was used to test a pilot surveillance system. Data for resistance patterns, for Sangre Grande Hospital (SGH), for ESBL producing E. coli and K. pneumoniae were downloaded from the Microscan Autoscan© for the period 2013 – 2016. ESBL presence in bacteria resistant to Cefotaxime (CTX), Ceftazidime (CAZ) and Ceftriaxone (CRO) were recorded. Data were stored in a Microsoft Excel© spreadsheet and inputted into IBM© SPSSv22. Data were displayed as resistance percentages for the year. No patient data were collected. Simple descriptive statistics were used. Results The number of organisms recovered from the database for the period 2013 to 2016 were:134E. coli and 59K. pneumoniae. Phenotypic resistance rates for ESBLs for 2013 to 2016 were: Ecoli: 2013: Resistance ranged from 22.2-29.6% with maximum resistance seen for CTX. 2014: Resistance ranged from 12.9- 22.2%, with maximum resistance seen for CRO. 2015: Resistance ranged from 21.4- =26.2%, with maximum resistance seen for CTX. 2016: Resistance ranged from 29.4- 32.4%, with maximum resistance seen for CRO and CTX. K pneumoniae: 2013: Resistance was 40% for all 3rd generation Cephalosporins. 2014: Resistance was 16.7% for all 3rd generation Cephalosporins. 2015: Resistance was 16.7% for all 3rd generation Cephalosporins. 2016: Resistance ranged from 52.6 – 63.2%, with maximum resistance seen for CAZ. Conclusion Phenotypic resistance rates in K. pneumoniae and E. coli were generally high. There was an overall increase in resistance from 2013 to 2016 for both K. pneumoniae and E. coli with greater resistance being seen in K. pneumoniae.