Characterization of Extended Spectrum Beta-lactamase and Carbapenamase Producing Enterobacteriaceae Causing Urinary Tract Infection among Children in Kenya: A Cross-Sectional Study

Introduction: Enterobacteriaceae causing urinary tract infections (UTI) have developed resistance to the commonly used antibiotics due to emergence of Extended Spectrum Beta-Lactamases (ESBLs) and Carbapenamase producing Enterobactericeae which are a public health problem worldwide. This study aims to determine the prevalence and characterize ESBLs and carbapenamase producing Enterobactericeae. Method: A cross-sectional study was carried out in Gertrude’s Children’s Hospital, Nairobi. 238 urine samples were collected from patients with urinary symptoms attending the outpatient department within the period 2020-2021. The urine were examined macroscopically and microscopically. Identification and antimicrobial susceptibility testing were done using VITEK® 2 Compact system (BioMérieux). Double disc synergy test and modified hodge tests were done as confirmatory tests for ESBLs and Carbapenamase phenotypes respectively. Polymerase Chain Reaction was used for the detection of blaCTX-M, blaTEM, blaSHV, blaKPC and blaOXA-48 genes. Results: From the 238 children sampled the prevalence of UTI caused by Enterobactericeae was 22.3%. The Enterobacteriaceae species isolated were Escherichia coli (84.9%), Klebsiella pneumoniae (5.66%), Proteus mirabillis (5.66%), Enterobacter aerogenes (1.89%) and Morganella morganii (1.89%). The isolated species were resistant to ampicillin. Meropenem had the highest susceptibility. Only E. coli species had the ESBLs (26.4%) and carbapenamase (1.9%) phenotypes. 100% had BlaCTX-M while 50% had blaTEM resistant gene. There was a significant association (p Conclusion: Ampicillin resistance resulted to use of alternative drugs and Meropenem was the drug of choice where increased resistance to the recommended drugs was noted. Further research on resistant genes is recommended.

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.

Extended-spectrum β-lactamase controversies

G.A.Jacoby 教授毕业于美国哈佛医学院,为国际知名的传染病学、微生物学和免疫学专家,曾长期担任美国麻省总医院传染病科医师,现任麻省 Lahey 医学中心传染病实验室主任,中国感染与化疗杂志特邀编委。长期以来 Jacoby 教授对细菌耐药机制有深入研究,尤其对细菌(肺炎克雷伯菌、大肠埃希菌等)产生质粒介导的超广谱β内酰胺酶(ESBL)以及喹诺酮类的耐药机制研究。曾发表多篇有关上述专题的权威性论著。此次本刊特邀 Jacoby 教授撰写有关 ESBL 的新进展,文中阐述目前 ESBLs 除通常所指质粒介导β内酰胺酶中扩大了酶水解的底物谱导致细菌对头孢噻肟、头孢他啶、氨曲南等抗生素耐药外,还包括许多具有不同特点的β内酰胺酶,其中某些酶产自共生菌。除 ESBL 外,AmpC 酶和各种碳青霉烯β内酰胺酶也可导致细菌对上述抗生素耐药,因此临床微生物实验室准确检出和鉴别各种β内酰胺酶,对于临床选用适宜的抗茵药十分重要。美国 CLSI(过去称为 NCCLS)推荐采用两步法(筛选及确证)检测细菌产 ESBL;但有的学者认为测定抗茵药物对细菌的 MIC,如用药后 T>MIC 在50%以上即可达到满意疗效,无需检测细菌是否产 ESBL。目前认为碳青霉烯类抗生素治疗产 ESBL 菌感染的疗效最为满意,但由此可能引起细菌对该类药物耐药,值得关注。采用大剂量头孢吡肟或哌拉西林-三唑巴坦治疗产ESBL 菌感染是否有效尚有争论,临床上对β内酰胺类最为耐药的菌株往往对几乎所有现用抗菌药耐药。黏菌素(或多黏菌素 B)曾成功的用于治疗此种多重耐药菌感染。此外替莫西林(temocillin,一种对β内酰胺酶稳定的青霉素类)与替加环素(tigecvcline,为米诺环素衍生物)体外对产 ESBL 菌有抗菌作用,但尚无临床研究资料。

T4-like coliphage ΦKAZ14 virulent to pathogenic and extended spectrum β-lactamase-producing Escherichia coli of poultry origin

Dear Editor,Bacteriophages(otherwise called phages)are a type of virus that infect bacteria.This viral type has found useful applications in the control of bacterial pathogens in foods and food processing environments.In addition,phages may be useful to prevent colonization and shedding of bacteria into the surrounding environment.

Phenotypic Detection and Susceptibility Pattern for the Detection of Extended Spectrum β-Lactamase-Producing <i>Klebsiella pneumonia </i>Isolates in Nairobi, Kenya

Klebsiella pneumoniae is an opportunistic pathogen that is an important cause of nosocomial infections. Detection of ESBL producers’ poses a special challenge for clinical microbiology laboratories, although ESBL producing pathogens are able to hydrolyze extended-spectrum penicillins, cephalosporins, and aztreonam, the minimum inhibitory concentrations (MIC) of some and perhaps even all of these agents may be within the susceptible range. The third generation cephalosporins have the reputation for being useful against a broad range of bacterial infections. However, resistance to these agents is something that must still be considered and creates obstacles for their clinical use. A total of 80 multi drug resistant clinical isolates of Klebsiella pneumoniae were obtained from a study on anaerobes associated with Pelvic Inflammatory disease (P.I.D), KEMRI S.S.C No.495. The isolates were identified by standard microbiological procedures. Antimicrobial susceptibility testing was carried out by Kirby-Bauer method. Upon identification, the antibiogram profiles of the isolates were determined and those resistant to third-generation cephalosporins were tested for production of ESBL. ESBL production among the multi drug resistant isolates was detected using the phenotypic confirmatory disc diffusion test (PCDDT) and double disk synergy test (DDST). While using standard double disk synergy test (DDST) as screening method for identifying potential ESBL producers, ceftriaxone was the most efficient antimicrobial in screening isolates as potential ESBL producers followed by cefotaxime.

Comparative Study of Three β Lactamase Test Methods in <i>Staphylococcus</i>aureus Isolated from Two Nepalese Hospitals

Background: β lactamase is a plasmid-encoded enzyme that hydrolyzes β lactam ring of β lactam antibiotics rendering them ineffective. These enzymes, produced by Staphylococcus aureus along with many other organisms, have hindered the use of many useful and once life-saving β lactam antibiotics from clinical practice. Methods: This study was aimed to compare three test methods-chromogenic, acidimetric and iodometric-for the detection of β lactamase enzyme produced by 404 nosocomial induced S. aureus isolated from two Nepali hospitals, Kathmandu based hospital (KBH) and Lalitpur based Hospital (LBH). The study was carried out following standard methodology during November 2007 to June 2009 in the Department of Microbiology, Institute of Medicine, Kathmandu, Nepal. Sensitivity, specificity, efficiency, positive predictive value, and negative predictive values of the tests were calculated taking penicillin resistance and sensitivity as the standard. Results: Chromogenic method was found to be the most sensitive (98.93%) and efficient (98.51%) test and had a high positive predictive value (99.46%). Sensitivity (98.4%) and efficiency (98.27%) of iodometric method was found to be comparable to chromogenic test;its specificity (96.55 %) and positive predictive value (99.73%) were the highest among the 3 tests. Acidimetric test was the least sensitive (97.33%) and efficient (96.78%). Of note, the sensitivity and specificity of these test methods have been compromised due to the negativity of few penicillin resistant isolates and positivity of some penicillin sensitive isolates, respectively. Conclusion: Chromogenic method was found comparatively to be the best test method for the detection of β lactamase production. However, in contrast to the other two test methods whose reagents can be locally and economically prepared, chromogenic test’s use has been impeded by its cost and unavailability in the local Nepali market.

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.

In vitro activity of β-lactamase inhibitors avibanvctam and relebactam in combination with β-lactams against multidrug-resistant Mycobacterium tuberculosis and mutations of resistance genes

Objective To evaluate the activity of six β-lactams in combination with three β-lactamase inhibitors against mycobacterium tuberculosis(MTB) in vitro.Methods A total of 105 multidrug-resistant tuberculosis (MDR-TB)strains from different regions of Henan province from January to September 2020 were included in this study.

Epidemiological and antibiotic resistant study on extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in Zhejiang Province

To investigate the epidemiological status of extended spectrum β lactamase (ESBL) producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) and the drug resistance profiles of such organisms Methods A total of 282 clinical isolates of E coli and 180 of K pneumoniae were collected from different districts of Zhejiang Province Inhibitor potentiated broth dilution tests were performed for detecting extended spectrum β lactamases Etests were performed to detect the drug resistance of these strains against nine commonly used antibiotics Results The prevalence of extended spectrum β lactamases in E coli and K pneumoniae was 34 0% and 38 3%, respectively The average prevalence of extended spectrum β lactamases in E coli and K pneumoniae was 35 7% The resistance prevalence of extended spectrum β lactamase producing strains to ceftazidime and cefotaxime was 40% and 26% respectively, so were those to cefepime, cefoxitin, piperacillin tazobactam, cefoperazone sulbactam, amikacin and ciprofloxacin All these strains were sensitive to imipenem Conclusion The results in this study showed that the prevalence of extended spectrum β lactamases was high, while extended spectrum β lactamase producing strains were resistant to most antimicrobial agents except imipenem

Antibacterial activity of Valeriana jatamansi against extended-spectrum β-lactamase producing Gram-negative bacteria causing urinary tract infections

Objective:To find out the antibacterial activity of Valeriana jatamansi(V.jatamansi)rhizomes against the extended-spectrumβ-lactamases(ESBLs)producing isolates of Enterobacteriaceae family.Methods:Confirmation of ESBLs producing Escherichia coli,Enterobacter aerogenes,Klebsiella pneumoniae and Hafnia alvei isolated from urinary tract infections was performed by double disc diffusion assay.Antimicrobial susceptibility of all ESBLs producing isolates was determined by disc diffusion method following guidelines of Clinical and Laboratory Standards Institute.Successive extraction of rhizomes of V.jatamansi was performed with hexane,chloroform and methanol using Soxhelt apparatus.These extracts were tested against the ESBLs producing isolates using well diffusion method.Results:Hexane extract showed significant results as compared to chloroform and methanol extracts with the maximum zone of inhibition(21 mm)while ciprofloxacin and amikacin were used as standard drugs.Conclusions:Findings of the study suggested that hexane extract of V.jatamansi can be used in combination with other antibiotics as alternative treatment for urinary tract infections caused by ESBLs producing strains of Enterobacteriaceae.

青霉烷砜/头孢哌酮的药理与临床

近代研究表明,许多革兰氏阳性菌和阴性菌能产生β内酰胺酶(β—lactamase),这些酶能将某些β内酰胺类抗生素结构中的β内酰胺环水解破坏,阻止其对病原菌发挥抗菌的作用,因而使这些病原菌对β内酰胺类抗生素产生耐药性,造成临床上控制感染的困难。

The Mechanism of Resistance of Pseudomonas Aeruginosa toβ-lactam Antibiotics and Clinical Significance

To study the resistant mechanism and clinical significance of pseudomonas aeruginosa toβ- lactam antibiotics,the outer mem brane permeability rate of30 P.aeruginosa strains to5 β- lactam antibiotics was m easured and their production ofβ- lactamase and theβ- lactam ase genes they carried detected. Furthermore,the relationship between the perm eability,β- lactam ase and the clinical effects ofβ- lactam antibiotics was observed. By using 1 4C- penicillin and liquid- scintillant isotope assay,the affinity of penicillin binding proteins(PBPs) was m easured and their roles in the resistant m echanism studied.Itwas revealed thatthe perm eability rate was higher in sensitive strains than in resistantones(P<0 .0 5 ) .All strains harbored1- 4 β- lactamase genes and produced β- lactam ase.Higher permeability rate and higher degree of stability toβ- lactamase indicated better clinical therapeutic effects. The affinity of PBPs changed little without regard to the perm eability andβ- lactam ase. These results suggested that the permeability of outer mem brane andβ- lacta- mase,but not PBPs,played im portant roles in the resistant mechanism of P. aeruginosa toβ- lac- tam antibiotics and affected the clinical therapeutic effectiveness of som e patients.

Hydrophilic/hydrophobic characters of antimicrobial peptides derived from animals and their effects on multidrug resistant clinical isolates

Multidrug resistant（MDR） pathogen infections are serious threats to hospitalized patients because of the limited therapeutic options. A novel group of antibiotic candidates, antimicrobial peptides（AMPs）, have recently shown powerful activities against both Gram-negative and Gram-positive bacteria. Unfortunately, the viability of using these AMPs in clinical settings remains to be seen, since most still need to be evaluated prior to clinical trials and not all of AMPs are potent against MDR clinical isolates. To find a connection between the characteristics of several of these AMPs and their effects against MDR pathogens, we selected 14 AMPs of animal origin with typical structures and evaluated their in vitro activities against clinical strains of extensive drugresistant Acinetobacter baumannii, methicillinresistant Staphylococcus aureus, extended spectrum β-lactamase-producing Pseudomonas aeruginosa and extended spectrum β-lactamase-producing Escherichia coli. Our results showed that these peptides＇ hydrophilic/hydrophobic characteristics, rather than their secondary structures, may explain their antibacterial effects on these clinical isolates. Peptides that are amphipathic along the longitudinal direction seemed to be effective against Gramnegative pathogens, while peptides with hydrophilic terminals separated by a hydrophobic intermediate section appeared to be effective against both Gramnegative and Gram-positive pathogens. Among these, cathelicidin-BF was found to inhibit all of the Gram-negative pathogens tested at dosages of no more than 16 mg/L, killing a pandrug-resistant A. baumannii strain within 2 h at 4×MICs and 4 h at 2×MICs. Tachyplesin III was also found capable of inhibiting all Gram-negative and Gram-positive pathogens tested at no more than 16 mg/L, and similarly killed the same A. baumannii strain within 4 h at 4×MICs and 2×MICs. These results suggest that both cathelicidin-BF and tachyplesin III are likely viable targets for the development of AMPs for clinical uses.

The relationship between antimicrobial consumption and the rates of resistance of Klebsiela pneumoniae in respiratory unit

Objective To investigate the relationship between the consumption of antibacterial agents and resistance rate of Klebsiela pneumoniae(KP)in the hospital respiratory unit for 3 consecutive years in 2005-2007.Methods The total antibacterial consumption expressed as defined DDDs/100BD,as well as resistance rate of total KP and producing ESBLs KP were collected,and their correlation was analyzed.Results The rate of resistance of KP to cefoperazone/sulbactam,Cefepime,Imipenem,Moxifloxacin was significantly positively associated with the consumption of Cefotaxime,Ceftazidime,Moxifloxacin,Amikacin respectively;A significant positive association was observed between the rate of resistance of KP to Piperacillin/Tazobactam,Ceftriaxone and the consumption of Imipenem;The rate of resistance of KP to Piperacillin,Cefotaxime,Ciprofloxacin was significantly positively associated with the consumption of Levofloxacin.ESBLs producing bacilli of KP were detected in 44 of 75 isolates(58.7%),The rate of resistance of producing ESBLs KP to Piperacillin/Tazobactam,Ceftriaxone was significantly positively associated with the consumption of Imipenem,Ceftazidime;A significant positive association was observed between the rate of resistance of producing ESBLs KP to Piperacillin,Imipenem and the consumption of Moxifloxacin.There was no significant correlation in other drugs.Conclusions A relationship existed between antimicrobial consumption and rates of resistance of KP in the hospital respiratory unit.We must use antibiotics carefully and with reason to control and lessen the drug resistance of bacterial.

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.

Study Frequency of Antibiotic Resistance Enzymes in Bacillus Species in Some of Foods

The subject of this study was to survey prevalence Beta lactamase enzyme in Bacillus species isolated from foods in Isfahan city in Iran. This is a laboratory study performed during 2009-2010 years in Isfahan. In this study, 150 samples of food, including juice ketchup, mayonnaise,

Drug treatment

930015 Treatment of soil-transmittedhelminth infections by helminthicides in currentuse.XU Longqi(许隆祺),et al.Instit ParasitDis,Acad Chin Pre Med,Shanghai 200025.Chin J Parasitol & Parasit Dis 1992;10(2):95—98.The efficacy of broad-spectrum helminthi-cides in current use was studied in HengshanCounty,Hunan Province.The vermicides

“超级病毒”来袭

最近科学家在一些曾在南亚接受过医疗服务或旅游的患者体内发现了一种几乎能抵御所有抗生素的超级细菌。更为严重的是,其中一些病人由于感染病况过于严重已不治身亡。