Occurrence of K1 and K2 serotypes and genotypic characteristics of extended spectrumβ-lactamases-producing Klebsiella pneumoniae isolated from selected hospitals in Malaysia

Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selected hospitals in Malaysia.Methods:A total of 192 K.pneumoniae isolates were collected and subjected to antibiotic susceptibility,hypermucoviscosity test and multiplex PCR to detect the presence of K1-and K2-serotype associated genes.Multilocus sequence typing(MLST)was performed on ESBL-producing K.pneumoniae isolates presented with K1 and K2 serotypes,followed by phylogenetic analysis.Results:A total of 87 out of 192(45.3%)of the K.pneumoniae isolates collected were ESBL producers.However,only 8.3%(16/192)and 10.9%(21/192)of the total isolates were detected to carry K1-and K2-serotype associated genes,respectively.Statistical analysis showed that K1 and K2 capsular serotypes were not significantly associated with ESBL phenotype(P=0.196).However,they were significantly associated with hypervirulent,as demonstrated by the positive string test(P<0.001).MLST analysis revealed that ST23 as the predominant sequence type(ST)in the K1 serotype,while the ST in the K2 serotype is more diverse.Conclusions:Although the occurrence of ESBL-producing isolates among the hypervirulent strains was low,their coexistence warrants the need for continuous surveillance.MLST showed that these isolates were genetically heterogeneous.

Phenotypic and Genotypic Characterization of Extended Spectrum Beta-Lactamases Producing Bacteria Causing Urinary Tract Infections among Expectant Women Attending Antenatal Clinic at Ruiru Sub County Hospital, Kenya

Background: Urinary tract infection (UTI) is a bacterial infection affecting males and females but is more prevalent in expectant women. ESBLs are bacteria with enzymes that make them resistant to many antibiotics, posing a significant health challenge. This study aims to determine the characteristics of ESBL-producing bacteria causing UTIs in expectant women. Methodology: A self-administered survey was carried out;300 expectant women were recruited using a random sampling method. A questionnaire was used to collect socio-demographic information. Urine samples were collected in sterile universal bottles and processed at the JKUAT Zoology laboratory. Urine samples were analyzed using urinalysis, microscopy, culture, and sensitivity testing. ESBL-producing bacteria were identified phenotypically using the double-disc synergy test (DDST) and genotyped for specific resistant genes using PCR. Results: UTI prevalence was 32.7% (98/300). UTI was significantly associated with the history of previous UTI (OR = 0.84, p = 0.02) and multigravida (OR = 0.14 p = 0.01). UTI was common in women aged between 28-37 years in their second trimester. Bacteria isolated were E. coli 57.1% (56/98), S. aureus 21.4% (21/98) K. pneumonia 11.2% (11/98) and Proteus spp 10.4% (10/98). Bacteria antibiotic resistance patterns were E. coli-tetracycline (91.1%), sulfamethoxazole (55.4%), cefotaxime (53.4%) and augmentin (53.4%). S. aureus-sulfamethozaxole (100%) and augmentin (71.4%), K. pneumoniae-sulfame-thoxazole (72.2%) cefotaxime (63.6%), chloramphenicol and tetracycline (54.5%). Proteus spp: tetracycline (100%), nitrofurantoin (90%), cefotaxime and chloramphenicol (50%). The proportion of ESBLs bacterial producers was 37.6% (29/77) and 44.8% (13/29) possessed ESBLs resistant genes;Bla CTX-M 53.8% (7/13), Bla SHV and Bla TEM 23.1% (3/13) each, Bla OXA (0%) was not detected. Conclusion: The study revealed a high proportion of ESBLs producing bacteria responsible for UTI in expectant women. ESBLs screening, routine culture and sensitivity testing will guide on proper management and empirical treatment of UTI patients thus reducing multi-drug resistance.

Prevalence and characteristics of extended spectrum β-lactamase-producing Escherichia coli from bovine mastitis cases in China

The aim of the study was to investigate the prevalence and characterization of extended-spectrum β-lactamase （ESBL）- producing Escherichia coli isolated from bovine mastitis cases in China. ChromID ESBL agar was used to confirm ESBL-producing E. coli. PCR and DNA sequencing were employed to characterize the genotype of ESBL-producers. Antimicrobial susceptibility was measured by disc diffusion. Overall, 73 of 318 E. coli isolates （22.96％） were identified as ESBL-producers. Of these ESBL-producing E. coli, the prevalence of blaCTX-M and blaTEM-1 was 97.26 and 71.23％, respectively. The predominant CTX-M-type ESBL was CTX-M-15 （65.75％）, followed by CTX-M-14 （10.96％）, CTX-M-55 （9.59％）, CTX-M-64 （5.48％）, CTX-M-65 （4.11％） and CTX-M-3 （1.37％）. This study is the first report of CTX-M-64 and CTX-M-65 in E. coli isolated from bovine mastitis. Furthermore, 72 ESBL-producing E. coli isolates （98.63％） were found to be multidrug-resistance. This study noted high prevalence and rates of antimicrobial resistance of ESBL-producing E. coli isolates from bovine mastitis cases in China.

Prevalence of Extended Spectrum Beta-Lactamase-Producing Escherichia coli in Broiler Chickens in YaoundéCapital City of Cameroon

Background: Escherichia coli are ubiquitous bacteria colonising both humans and animals. Extended spectrum β-lactamase-producing E. coli has been selected as a suitable indicator for the monitoring and surveillance of antimicrobial resistance. Death due to resistant bacteria is continuously rising in Cameroon, but the contribution of the aviary sector is not well studied. Therefore, this study aimed to investigate the resistance profile of extended spectrum beta-lactamases-producing Escherichia coli strains, isolated from faeces of broiler chickens in Yaoundé, capital city of Cameroon. Methods: A cross-sectional descriptive study was carried out from February to June 2020. Escherichia coli were isolated from samples of broilers in poultry farms in Yaoundé and submitted to the extended spectrum β-lactamase screening. The logistic regression was used to assess the statistical association of a significance threshold p-value of 0.05. Results: Out of 385 faecal samples collected in broiler farms, 114 Escherichia coli isolates were obtained out of which 30 (26.32%) were Extended Spectrum Beta-Lactamases-producing Escherichia coli. These isolates revealed high resistance to all antibiotic families. Poor storage conditions for feeds and the proximity to latrines, the troughs on the ground, the lack of foot bath and uniforms, the inadequate treatment of faeces, the poor usage of preventive antibiotics and the lack of water treatment have been identified as risk factors to faecal carriage of ESBL-producing Escherichia coli. Conclusion: This work reveals the emergence of Extended Spectrum Beta-Lactamases-producing Escherichia coli in poultry farms in Yaoundé and the failure in the biosecurity system. As such, the awareness of poultry breeders on the respect of biosecurity measures may be an effective tool to tackle antimicrobial resistance, specifically in livestock industries using a One Health approach.

Antimicrobial resistance, genotypic characterization and pulsed-field gel electrophoresis typing of extended spectrum β-lactamases-producing clinical Escherichia coli strains in Macao, China

Background The rise of the production of CTX-M class extended spectrum β-lactamases （ESBLs） has been well documented in traveling countries but no data are found for Macao, an international travel city. The objectives of this study were to identify the antimicrobial resistance pattern, and determine the prevalence, genotype and clonal relationship of ESBLs in 209 clinical Escherichia coli strains from Macao, China. Methods Antimicrobial susceptibility test was performed to determine the resistance patterns of the isolates using the disk diffusion method with 17 antimicrobial agents. Phenotypic detection was screened and confirmed according to the Clinical and Laboratory Standards Institute. Genotypic characterization was detected by isoelectric focusing analysis, polymerase chain reaction and sequencing. The clonal relationship between the different ESBL isolates was studied by pulsed-field gel electrophoresis （PFGE）. Results Imipenem and meropenem exhibited 100% susceptible among 209 strains. Overall, 82.3%, 67.3%, 52.9%, 51.2% and 51.0% of the isolates displayed resistance to ampicillin, tetracylcline, ciprofloxacin, sulfamethoxazole trimethoprin and gentamycin. The prevalence rate of ESBLs was 30.1%. Antibiotic resistances were found to be significantly higher among the ESBL producing group compared to non-ESBL producing group. We detected CTX-M-14 to be the major genotypic characterization of ESBLs （76.2%）. Two strains showed indistinguishable patterns by PFGE. Conclusions The prevalence of antimicrobial resistance is alarming high in Macao. Antimicrobial resistance is significantly higher among the ESBL producing group. This study documented CTX-M-14 as the predominant ESBL type. Although indistinguishable pattern was found between two strains, it was too small to decide whether any of the investigated strains was epidemic. Our findings may be also pertinent for other geographic areas undergoing similar travel characteristics to understand the corresponding effects on bacterial populations.

What is the prognosis of emphysematous pyelonephritis associated with extended-spectrum beta-lactamases producing microorganisms?

Objective:To describe the microbiological characteristics in emphysematous pyelonephritis(EPN),demonstrate the frequency of extended-spectrum beta-lactamase(ESBL)microorganisms,and determine if these microorganisms are associated with the prognosis of patients with EPN.Methods:We conducted a retrospective study in patients with a diagnosis of EPN in a tertiary care hospital of the northeast region of Mexico during the period from January 2011 to January 2016.Clinical variables were analyzed to determine association with the presence of ESBL-producing microorganisms.Statistical significance was set with p<0.05.Results:A total of 63 patients were included;55(87.3%)of them were females,with a median age of 55(interquartile range:45-65)years.Conservative management was indicated in 38.1%;42.9%were treated with ureteral stent;12.7%with open or percutaneous drainage;15.8%with early nephrectomy;and 9.5%with delayed nephrectomy.Reported mortality was 13(20.6%)cases;23(36.5%)cases required admission to the intensive care unit.The most frequent microorganism isolated was Escherichia coli(n=34,53.9%).ESBL microorganisms were found in 31.7%of the population.No significant association of ESBL was found with admission to the intensive care unit,or with increased mortality.Conclusions:To our knowledge,this is the first study that evaluates ESBL microorganisms as a prognostic factor in EPN.Risk factors associated with a poor prognosis in patients with EPN have been described.The microbiological factors,specifically ESBL-producing bacteria,do not seem to influence in the prognosis of these patients.

Determination of the prevalence of extended spectrum β-lactamase in clinical samples collected from Dehradun City Hospital

Objective:To detect extended spectrumβ-lactamase(ESBL)and determine its prevalence in various clinical samples collected from Dehradun City Hospital.Methods:The samples were first cultured in MacConkey’s agar plates by streak plate method,then identified by Gram staining and biochemical tests.The isolated bacterial strains were then tested for antibiotic susceptibility by Kirby-Bauer method.The ESBL detection is then carried out by double disc diffusion method.Results:Off the 56 samples cultured,21 strains were identified which were six Escherichia coli(E.coli),six Klebsiella,four Proteus,four Pseudomonas aeruginosa(P.aeruginosa)and only one Acinetobacter.Eight out of 21(38.1%)strains including three of E.coli,three of Klebsiella and two of P.aeruginosa,were found to be resistance to all five antibiotics(piperacillin,amikacin,ampicillin,gentamicin,and ciprofloxacin).Initial screening using four antibiotics(cefotaxime,ceftazidime,aztreonam and ceftriaxone)and the final confirmatory test using ceftazidime/clavulanic acid and ceftazidime alone showed that 19.05%of all strains isolated were ESBL producers.Individually,16.67%E.coli,16.67%Klebsiella pneumoniae,25%P.aeruginosa and 100%Acinetobacter were found to be ESBL producers.Conclusions:Antibiotic resistance by ESBL has become a major risk factor worldwide,therefore routine checkup and accordingly prescription are suggested.

Molecular Identification of Co-Existence of Carbapenemase and Extended-Spectrum <i>β</i>-Lactamase Genes in <i>Klebsiella pneumoniae</i>Clinical Isolates, and Their Phylogenetic Patterns in Kenya

The increasing incidence of multidrug-resistant Klebsiella pneumoniae strains has become a serious global healthcare problem. Additionally, the carriage of both extended-spectrum ß-lactamase and carbapenemase genes on plasmid and genomic DNA in K. pneumoniae clinical isolates has not been documented in Kenya. This study aimed to assess the presence of extended spectrum β-lactamase (ESBL) and carbapenemase genes on genomic and plasmid DNA in K. pneumoniae, and classify these super-bug clinical isolates based on their phylogenetic patterns. The identification of Klebsiella-like clinical isolates (n = 20) collected from Kenyatta National Hospital in Nairobi was performed using API 20E Kit. Screening and confirmation for ESBL and carbapenemase phenotypes were conducted using Kirby-Bauer disk diffusion susceptibility test protocol. Conventional PCR technique was used to characterize ESBL and carbapenemase resistant genes on both genomic and plasmid DNA. Subsequently, 16S rRNA gene amplification and sequencing were performed. The 16S rRNA gene contiguous sequences of the bacterial isolates were analyzed using the ChromasPro. The gene sequence was compared with the sequences in GenBank database, using the BLAST program of NCBI to obtain the nearest phylogenetic neighbours from the databases. Then, the sequences of MDR K. pneumoniae and its relatives were aligned using ClustalW. The evolutionary history was inferred by using the maximum likelihood algorithm in MEGA MX. The phenotypic data of antibiotic susceptibility testing revealed that 2/20 (10%) clinical isolates were resistant both to imipenem and meropenem and producers of carbapenemase. These isolates were carbapenemase producers but not extended β-lactamases. However, 3/20 (15%) isolates that co-harboured blaNDM-1, blaIMP, blaTEM, and bla-OXA were identified during genotypic analysis. The positive control used separately yielded the expected band sizes for blaIMP (275 bp), blaOXA-48 (438 bp), and BlaKPC (798). The phylogenetic analysis showed the dual ESBL and carbapenemase producing Klebsiella pneumoniae could be classified as K. pneumoniae strain DSM 30104 and K. pneumonia subsp. pneumoniae strain GMH1080. This study confirmed the co-existence of ESBL and carbapenemase genes in Klebsiella pneumoniae on both bacterial genomic and Plasmid DNA, and demonstrated that the isolates are evolutionarily distinct. These findings raise a concern about the genotypic diversity of antibiotic resistance genes in bacterial isolates and their location. We, therefore, recommend an alternative management approach to combat these MDR bacterial isolates as well as frequent molecular surveillance programs to support antimicrobial stewardship.

Total Alkaloids from Sophora Alopecuroides L.Increase Susceptibility of Extended-Spectrum β-Lactamases Producing Escherichia coli Isolates to Cefotaxime and Ceftazidime

Objective： To evaluate the antimicrobial activity of total alkaloids extracted from Sophorea alopecuroides L. （TASA） against clinical isolated extended-spectrum beta-lactamases （ESBLs） producing Escherichia coil （E.. coil） strains. Methods： The antibacterial activity of TASA either itself or in combination with cefotaxime （CTX） or ceftazidime （CAZ） was investigated by using the microbroth dilution method and phenotypic confirmatory disk diffusion test against three clinical isolated ESBLs-producing E. coil strains; the interactions of TASA and C＇I＇X or CAZ were ascertained by evaluating the fractional inhibitory concentration index （FICI）. Results： The antibacterial activity of either TASA itself or in combination with C＇IX or CAZ was found. The minimum inhibitory concentration （MICs） of TASA against the ESBLs producing isolates was 12.5 mg/mL. In the combinations with a sub-inhibitory concentration of TASA, a synergistic effect on CTX and CAZ against the ESBLs producing isolates was observed. Similarly, the isolates exposed to lower dose of TASA yielded an increased susceptibility to CTX and CAZ by 8-16 folds determined by microdilution assay. Moreover, enzymatic detection of ESBLs demonstrated that TASA induced reversal resistance to CTX and CAZ partially by a mechanism of inhibition of ESBLs activity in these isolates. Additionally, in the tested isolates following the exposure of TASA, molecular analysis verified the SHV-type beta-lactamase encoding ESBL gene in these isolates, and no mutation was introduced into the ESBL gene. Conclusions： These results suggest that TASA could be used as a source of natural compound with pharmacological activity of reversal resistance to antimicrobial agent. These findings also indicated that the application of the TASA in combination with antibiotics might prove useful in the control and treatment of infectious diseases caused by the ESBLs producing enterobacteriaceae.

Drug resistance of infectious pathogens after liver transplantation

BACKGROUND: Infection in liver recipients is related to high risk of transplantation failure and mortality. Infectious agents isolated from 55 liver recipients from January 2003 through June 2005 were studied to improve the anti-infectious therapy. METHODS: Pathogens were isolated from routine culture. K-B method was used to examine the drug susceptibility. Extended spectrum β-lactamase, AmpC β-lactamase and Van gene in E. coli were examined by the agar-dilution susceptibility test and Nitrocefin test. RESULTS: Thirty-nine of the 55 recipients got infection. The 513 strains of pathogens isolated from 1861 specimens were predominantly Gram negative bacteria and over 40% of them showed resistance to more than 4 drugs. The positive rates of extended spectrum β-lactamse and AmpC β-lactamse production in E. cloacae were 32.4% and 36.8%, in E. coli were 33.8% and 10.5%, but the rates of these 2 bacteria producing both lactamses were 24.3% and 7.0%. The β-lactamse production rates of Enterococcus faecalis and En-terococcus faecium were 8.8% and 11.1%, and the resistance rates to vancomycin were 11.2% and 18.5%, respectively. CONCLUSIONS: Infectious pathogens isolated from liver recipients are potent and multiple drug resistant. ESBLs and AmpC β-lactamases are the major factors associated with Gram negative drug resistance. The infection of En-terococcal species presents as a particular challenge.

Clinical and Microbiological Characteristics of Patients with Complicated Intra-abdominal Infections in Intensive Care Unit

In order to investigate the clinical and microbiological characteristics of patients with complicated intra-abdominal infections(cIAIs)in intensive care unit(ICU),the clinical data of 612 cIAIs patients from January 2016 to December 2018 were retrospectively collected.Clinical characteristics,distribution of pathogens and drug resistance were statistically analyzed.It was found that patients with community-acquired intra-abdominal infections(CA-IAIs)made up a majority of cIAIs patients.The positive rate of abdominal drainage fluid culture was 55.56%.Gramnegative bacteria accounted for the majority,the most commonly isolated bacteria of which were Escherichia coli(20.96%),Klebsiella pneumoniae(10.20%)and Pseudomonas aeruginosa(5.57%).The most commonly isolated gram-positive bacteria were Enterococcus(16.88%)and Methicillinresistant staphylococcus aureus(MRSA,3.90%).Enterobacter isolates showed high resistance rate to most cephalosporins and low resistance rate to piperacillin/tazobactam and carbapenems.Extended spectrum beta-lactamase(ESBL)screen positive isolates from CA-IAIs patients showed an increasing trend in past three years.Enterococcus and MRSA showed high resistance rate to clindamycin,quinolone,erythromycin and tetracycline,while they showed high sensitivity rate to linezolid,tegacycline,teicoplanin and vancomycin.Our results indicate that isolated bacteria from abdominal drainage fluid show high resistance rates to commonly used antibiotics in ICU patients with cIAIs.The curative effects on diseases should be monitored continuously when antibiotics are used.Meanwhile,we should always keep eyes on drug-resistant bacteria,especially when the treatment efficacy is not good.

In vitro biofilm formation in ESBL producing Escherichia coli isolates from cage birds

Objective:To determine biofilm and hydrophobicity formation ratios in extended spectrum beta lactamases(ESBL) synthesizing Escherichia coli isolates which were isolated from feces samples of 150 cage bird species randomly taken from pet shops in Hatay province,Turkey.Methods:In vitro biofilm production of 4 ESBL positive isolates were performed by Congo Red Agar(CRA),Standard Tube(ST) and Microtitre Plate(MP) methods while their hydrophobicity were examined by bacterial adhesion to hydrocarbon(BATH) test.Results:In the examined isolates,while biofilm production was found to be negative by CRA method,highest biofilm producing strain,among 4 bacteria was determined to be A42 by ST and MP methods.The Scanning Electron Microscopy(SEM) also displayed these confirmed findings.The hydrophobicity values of strains were determined to be between 22.45%and 26.42%.Conclusions:As a result,biofilm formation in cage bird feces originated ESBL positive Escherichia coli isolates was performed for the first time in Turkey.In order to present the relation between pathogenicity and biofilm production in animal originated ESBL positive isolates,further studies are required.

Near Future Perspective of ESBL-Producing Klebsiella pneumoniae Strains Using Mathematical Modeling

While antibiotic resistance is becoming increasingly serious today,there is almost no doubt that more challenging times await us in the future.Resistant microorganisms have increased in the past decades leading to limited treatment options,along with higher morbidity and mortality.Klebsiella pneumoniae is one of the significant microorganisms causing major public health problems by acquiring resistance to antibiotics and acting as an opportunistic pathogen of healthcare-associated infections.The production of extended spectrumbeta-lactamases(ESBL)is one of the resistance mechanisms of K.pneumoniae against antibiotics.In this study,the future clinical situation of ESBL-producing K.pneumoniae was investigated in order to reflect the future scenarios to understand the severity of the issue and to determine critical points to prevent the spread of the ESBL-producing strain.For evaluation purposes,SIS-type mathematical modeling was used with retrospective medical data from the period from 2016 to 2019.Stability of the disease-free equilibrium and basic reproduction ratios were calculated.Numerical simulation of the SISmodel was conducted to describe the dynamics of non-ESBL and ESBL-producing K.pneumoniae.In order to determine the most impactful parameter on the basic reproduction ratio,sensitivity analysis was performed.A study on mathematical modeling using data on ESBL-producing K.pneumoniae strains has not previously been performed in any health institution in Northern Cyprus,and the efficiency of the parameters determining the spread of the relevant strains has not been investigated.Through this study,the spread of ESBL-producing K.pneumoniae in a hospital environment was evaluated using a different approach.According to the study,in approximately seventy months,ESBL-producing K.pneumoniae strains will exceed non-ESBL K.pneumoniae strains.As a result,the analyses showed that hospital admissions and people infected with non-ESBL or ESBL-producing K.pneumoniae have the highest rate of spreading the infections.In addition,it was observed that the use of antibiotics plays a major role in the spread of ESBL-producing K.pneumoniae compared to other risk factors such as in-hospital transmissions.As amatter of course,recoveries fromKlebsiella infections were seen to be the most effective way of limiting the spread.It can be concluded from the results that although the use of antibiotics is one of themost effective factors in the development of the increasing ESBL-producing K.pneumoniae,regulation of antibiotic use policy could be a remedial step together with effective infection control measures.Such steps may hopefully lead to decreased morbidity and mortality rates as well as improved medical costs.

Phenotypic and genotypic detection of extended-spectrum β-lactamase (ESBL) producing Escherichia coli isolated from urinary tract infections in Zabol,Iran

Objective:To investigate the role of a rapid polymerase chain reaction(PCR)assay in comparison with traditional empiric therapy in detection of extended spectrum β-lactamase(ESBL)producer Escherichia coli(E.coli).Methods:Ninety isolates of E.coli from urinary tract infection were collected and screening of ESBL resistance using disc diffusion method,minimum inhibitory concentration(MIC)for ceftazidime and detection of TEM resistant gene by PCR were done.Results:The results of disc diffusion method showed that forty out of ninety E.coli isolates were ESBLs producing organisms.Antibiotic susceptibility of E.coli isolates to 9 antibacterial agents were evaluated.However,all isolated E.coli were resistant to all 9 antibacterial agents by these percentage:ceftriaxon(100%),ceftazidime(100%),amoxicillin(100%),erythromycin(100%),azithromycin(95%),cefixime(87.5%),tetracyclin(87.5%),nalidixic acid(85%)and difloxcain(75%).The abundance of antibiotic-resistant TEM gene according to PCR was 30%.Totally 82.5%of strains tested by MIC were observed as ceftazidime-resistant.Conclusions:We conclude that the TEM gene PCR assay is a rapid,sensitive and clinically useful test,particularly for the early detection of ESBLs-producing E.coli.

Phenotypic and Genotypic Characterisation of Antibiotic Resistance in Escherichia coli, Klebsiella spp., and Listeria monocytogenes Isolates from Raw Meat Sold in Nairobi

Worldwide, the increase in antimicrobial resistance (AMR) is a public health concern. Food-borne associated antibiotic-resistant pathogens can contaminate raw meat during slaughter, transportation, and at sale points. A cross-sectional study was conducted from March 2021 to December 2021 to determine antimicrobial susceptibility patterns and characterize the molecular basis of resistance in E. coli, Klebsiella spp., and L. monocytogenes contaminating raw meat collected from retail outlets in Nairobi. Isolation and identification of the strains were done using the standard culture methods and PCR. Antimicrobial susceptibilities of the recovered strains were determined using disk diffusion while the presence of antibiotic resistance gene determinants;blaTEM, blaCTX-M, blaOXA, sul, and qnrS was done using PCR. Of 270 samples collected, 163 (60%) Escherichia coli, 19 (7%) Klebsiella spp., and L. monocytogenes 3 (1.1%) were recovered. Among Escherichia coli, high antibiotic resistance was found to Erythromycin 161 (98%) and ampicillin 88 (54%) while low resistance was found against imipenem 2 (1%). Similarly, high resistance was found among Klebsiella spp. to Erythromycin 19 (100%) and ampicillin 12 (63%) low resistance to ceftazidime 1 (5%), cefotaxime 1 (5%), aztreonam 1 (5%), and chloramphenicol 1 (5%). One isolate among the three Listeria monocytogenes strains isolated was resistant to Trimethoprim-sulfamethoxazole. No resistance was exhibited to gentamycin by all Klebsiella spp. The prevalence of multidrug-resistant (resistance to three or more classes of antibiotics) isolates was 95/182 (52.2%). The common resistance pattern observed was Erythromycin, ampicillin, tetracycline, and trimethoprim-sulfamethoxazole with a prevalence of 19 (20%). ESBL was confirmed in isolates that harbored: blaTEM (65%), blaCTX-M (44%), blaOXA (33%) while sul and qnrS were detected in 46.7% and 13.6% respectively. Circulation of antibiotic-resistant and MDR isolates found in this study could play a role in the dissemination of AMR among food-borne bacteria and suggest potential food safety and public health risk. Therefore, enhanced surveillance for antibiotic-resistant organisms in raw meat for early detection of emerging resistant bacteria species in the food chain is recommended.

Phenotipic Prevalence of Antibiotic Resistance in Gabon

Background: The increasing phenomenon of bacterial resistance to antibiotics is a real public health problem. The main causes are poor management of hygiene and water quality, but also the use of antibiotics without precaution. The objective of this study was to isolate and determine the antibiotic resistance profile of the different bacteria found in the main hospitals and bacteriology laboratories in Gabon. Methods: 6034 samples were taken from hospitals in seven main cities of Gabon, and analyzed according to the usual techniques. The pathogenic strains were identified by Matrix-Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometry. Antimicrobial susceptibility testing was performed by the agar disc diffusion method, according to the Antibiogram Committee of the French Society for Microbiology guidelines. Results: 974 pathogenic bacterial strains were found, including 890/974 (91.4%) Gram-negative bacilli. The systematic antimicrobial susceptibility testings identified 160/974 (16.4%) multi-resistant strains. Escherichia coli was the most represented species. 12.5% - 25% of Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Citrobacter sedlakii strains were resistant to amoxicillin + clavulanic acid, third and fourth generation cephalosporins. Aminoglycoside resistance rates of 8.5% - 19% were also noted. 4.5% to 25% of the bacteria found were resistant to quinolones and cotrimoxazole. Resistance rates to carbapenems ranged from 1% to 10.5%. 16% of Staphylococcus aureus were methicillin-resistant (MRSA). Rates of extended spectrum beta-lactamase-producing enterobacteriaceae (ESBL-PE) ranged from 2.5% to 25%. Conclusion: This study showed an increasing evolution of bacterial resistance to antibiotics that are spreading throughout Gabon. This constitutes a threat to the health of Gabonese population.

Antimicrobial Resistance and β-Lactamase Production among Hospital Dumpsite Isolates

Metallo-β-Lactamases (MBLs) and Extended Spectrum β-Lactamses (ESBLs) have emerged world-wide as a significant source of β-lactam resistance. The emergence of MBLs and ESBLs encoded on plasmids among Gram-negative pathogens in hospital dumpsites was investigated. Soils of different government and private hospitals were collected and processed following standard bacteriological techniques. Antimicrobial susceptibility testing was carried out by the disk-diffusion technique using Ceftazidime (30 μg), Cefuroxime (30 μg), Cefotaxime (30 μg), Cefixime (5 μg), Trimethprim-sulfamethoxazole (25 μg), Gentamycin (100 μg) Amoxicillin-Clavunalate (30 μg), Ciprofloxacin (5 μg), Ofloxacin (5 μg), Nitrofurantoin (300 μg) and Imipenem (10 μg). The role of plasmids in resistance was evaluated by subjecting isolates to curing using Sodium Dodecyl Sulfate (SDS). ESBLs production by Double-Disk Synergy Test (DDST) was carried out. Isolates resistant to Imipenem were subjected to a confirmatory test using Modified Hodge’s test and to MBLs production by DDST. Eighty-two Gram-negative isolates comprising of 32 (39.02%) Escherichia coli, 20 (24.39%) Serratia marcescens, 14 (17.07%) Klebsiella pneumonia, 10 (12.28%) Proteus mirabilis and 6 (7.32%) Enterobacter aerogenes were obtained. Susceptibility results revealed a 100% resistance of all isolates to Ceftazidime, Cefuroxime, Cefixime, Amoxycillin-clavulanate and Cefotaxime. A total of 66 (80.48%) isolates harboured plasmids out of which 26 (31.71%) isolates were ESBL producers. MBLs production was observed in 8 (25.00%) E. coli, 2 (2.41%) Klebsiella pneumonia and 2 (2.41%) Proteus mirabilis isolates. All MBLs producing isolates were ESBLs producers. The finding of highly resistant isolates producing ESBLs and MBLs in a hospital environment is quite disturbing and should be addressed urgently.

New Test Light Spectrum Design for L/U-Band Extended Optical Fiber Line Testing System

This paper describes a new design for the test light source of an L/U-band extended optical fiber line testing system and the side-band suppresser ratio of the test light should be more than 70 dB.

Current epidemiologic features and health dynamics of ESBL-producing Escherichia coli in China

Extended‐spectrumβ‐lactamase(ESBL)‐producing Escherichia coli(E.coli)are widespread in China,with occurrences documented in humans,animals,and the environment.The dissemination of ESBL‐producing E.coli is likely facilitated by the widespread use of antibiotics in human and animal agriculture,the presence of antibiotic‐resistant bacteria(ARBs)in animal feces,and close human‐animal interactions.Plasmids,particularly those belonging to incompatibility(Inc)group,such as IncF,IncI,and IncH families,play a vital role in facilitating the horizontal gene transfer of ESBL genes across various sectors,from humans to animals and the environment.IS 26 and IS 1 elements also significantly influences the mobilization and evolution of antibiotic‐resistance genes(ARGs),contributing to the spread of ESBL‐producing E.coli.blaCTX‐M-14,blaCTX-15,and blaCTX‐M-55 are prevalent in ESBL‐producing E.coli across the three domains and are often found in con-junction with other ARGs.Considering these challenges,it is imperative to take proactive measures to prevent the further spread of ARBs.This includes the judicious and responsible use of antibiotics and efforts to mini-mize contact with animal feces.Sector‐specific strategies should be developed to effectively educate and engage relevant personnel in tackling this multifaceted problem.These efforts are vital to combat the dissem-ination of ESBL‐producing E.coli and preserve public health.

ANALYTIC METHOD FOR INVERSING THE OPEN BOUNDARY CONDITIONS IN A SEMI-CLOSED SEA AREA—CASE I FOR INVERSING THE TIDAL LEVELS AT OPEN BOUNDARY

In this paper, a computational case was employed to describe thecomputational procedure for inversing the tidal level open boundary conditions using an analyticmethod. The area for finding the solution is a circular area with a circular arc with the openingangle 60°-being the open boundary and the other circular arc being the solid wall boundary.Proceeding from the reestablished elliptic partial differential equation satisfied by the tidallevel function, the extended spectrum method was used to derive the general solution of the equationfor the sea of constant depth, and the impermeable solid wall condition (the second class boundarycondition) and the adequately specified open boundary conditions were then applied to determine theundetermined coefficients of the general solution, thus obtaining the tidal level distributionfunction. In this way, both the first and second class boundary values at the solid wall boundarywere obtained. With the above boundary values as the boundary conditions, the tidal level values atthe open boundary were then inversed by means of the general solution of tidal wave equation. Thevalidity of inversion method could be verified by comparing the inversed tidal level distributionswith the originally specified open boundary values.