Extended-spectrum beta-lactamase enzymes in clinical isolates of Enterobacter species from Lagos, Nigeria

Extended-spectrum beta-lactamases in clinical isolates of Escherichia coli and Klebsiella pneumoniae recovered from patients at the Tamale Teaching Hospital, Ghana

INTRODUCTION

Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae are pathogens of significant public health interest for which new antibiotics are urgently needed.

AIM

To determine the prevalence of ESBLs in E. coli and K. pneumoniae isolates from patients attending the Tamale Teaching Hospital (TTH) in Ghana.

METHODOLOGY

The study was a cross-sectional study involving convenience sampling of E. coli and K. pneumoniae isolates from consenting patients' clinical specimens, between April and June 2015. Antimicrobial susceptibility test was performed, and ESBL-producer phenotypes were further screened for BlaTEM, BlaSHV, and BlaCTX-M genes. Patients' clinical data were additionally collected using a structured questionnaire.

RESULTS

Of the 150 non-duplicate E. coli and K. pneumoniae isolates identified, 140 were confirmed as E. coli (84%, n = 117) and K. pneumoniae (16%, n = 23). Of these, sixty-two (44%) [E. coli (84%; n = 52); K. pneumoniae (16%; n = 10)] phenotypically expressed ESBLs. The proportion of ESBL-producing isolates was higher in adults (15-65 years) than in neonates (< 28 days) (p = 0.14). Most of the isolates showed a high percentage resistance to ampicillin (96%) and tetracycline (89%), but a relatively lower resistance to amikacin (36%). No isolate was resistant to meropenem. More ESBL producers were multidrug resistant compared to non-ESBL-producers [23% (14/62) versus 18% (14/78); p = 0.573]. Overall, 74% (n = 46) of the ESBL genotypes expressed BlaCTX-M-1 genes, followed by 63% (n = 39) BlaTEM, and 16% (n = 10) BlaSHV. The study showed a high prevalence of ESBL-positive E. coli and K. pneumoniae, mostly CTX-M-1 producers at TTH.

CONCLUSION

Routine laboratory ESBL screening is warranted to inform patient management.

Prevalence of multidrug-resistant and extensively drug-resistant phenotypes of Gram-negative bacilli isolated in clinical specimens at Centre Hospitalo-Universitaire Ibn Rochd, Morocco

Introduction

antimicrobial resistance in gram-negative bacilli is one of the major concerns in public health. We aimed to evaluate gram-negative bacilli epidemiology, antimicrobial profiles, and the resistance´s mechanism for Enterobacteriaceae isolated from specimens of hospitalized patients in wards of University Hospital Center Ibn Rochd of Casablanca, Morocco.

Methods

a prospective study of the patient's specimens, collected from December 2016 to 31st March 2017. Isolation and identification were performed using conventional biochemical tests. According to the European Committee on Antimicrobial Susceptibility Testing guidelines, antibiotic susceptibility was determined. Polymerase Chain Reaction (PCR) was used to detect β-lactamase and carabapenemase genes: CTX-M, SHV, TEM, OXA-48, NDM, and VIM among the Enterobacteriaceae.

Results

according to inclusion criteria, 38 Enterobacteriaceae, 25 Acinetobacter baumannii (A. baumannii), and 10 Pseudomonas aeruginosa (P. aeruginosa) were included during the study period; these bacteria were mainly responsible for bacteremia. Fifty-five percent of enterobacteria were extended-spectrum β-lactamase (ESBL), 42% EBSL and carbapenemase, and 3% carbapenemase, with high coresistances. Eighty-four percent of A. baumannii were XDR. All P. aeruginosa were MDR; amikacin showed the best activity (70% susceptibility). The genotypic approach revealed the presence of blaCTX-M, blaSHV, blaTEM in 68%, 22%, and 11% respectively. Of the 22 carbapenemase-producers, 41% were blaOXA-48 and 18% blaNDM; none had blaVIM. Furthermore, various genes coexistence were detected: blaCTX-M+blaOXA-48; blaCTX-M+blaNDM; blaCTX-M+blaSHV+blaOXA-48; and blaSHV+blaOXA-48.

Conclusion

findings revealed highly resistance rate among isolates. This raises the need to control antibiotics and regular screening to identify dynamics promoting resistance. Thus, we recommend developing antimicrobial stewardship programs and improving hygiene systems to prevent the nosocomial spreading of these phenotypes in our center.

Systematic Review and Meta-analysis on Extended-Spectrum β-lactamases Producing Klebsiella pneumoniae in Nepal

Objective

This systematic review and meta-analysis aimed to assess the pool estimates of extended-spectrum β-lactamases producing K. pneumoniae (ESBL-KP) and study their drug resistance profile by evaluating the studies from Nepal.

Methods

A literature search was carried out in PubMed, Google Scholar, and NepJOL to screen all articles on ESBL-KP published between 2011 and 2021 from Nepal. This review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Relevant data were extracted, and R language 4.2.0 software was used for statistical analysis.

Results

The pooled prevalence of K. pneumoniae was 5%, while the pooled prevalence of ESBL and multidrug resistance (MDR) in K. pneumoniae were 23% and 55%, respectively. Imipenem was the drug of choice (in vitro) against ESBL-KP infection.

Conclusion

Our analyses showed a high prevalence of ESBL-KP and their high resistance toward commonly used drugs. This study highlights the need for the development of new antibiotics for the management of ESBL-KP infections.

Genotypic characterization of extended-spectrum β-lactamase producing urinary isolates among pregnant women in Ho municipality, Ghana

Objective

The case of antibiotic resistance has become a major global concern and Extended Spectrum β-lactamase (ESBL) producing organisms have so far remained the biggest culprit. The consequences of urinary tract infection (UTI) and antibiotic resistance among pregnant women cannot be underestimated. We investigated UTI and ESBL production among urinary pathogens isolated from pregnant women.

Method

We obtained non-repeat, clean catch midstream urine samples from 1345 pregnant women suspected of having UTI for bacterial identification at the Ho Teaching Hospital Laboratory between June 2013 and March 2015. The isolates were taken through relevant biochemical testing for identification and then subjected to antimicrobial agents for susceptibility testing using the disc diffusion method. We tested for ESBL production by the combined disc method and ESBL positive (+ESBL) phenotype isolates were genotyped for Bla_TEM, Bla_SHV, and Bla_CTX-M using polymerase chain reaction (PCR). Data were analyzed using SPSS v24 and p-values < 0.05 were considered statistically significant.

Results

Of the 1345 urine samples tested, 230 (17.1%, 95% CI: 15.1%-19.1%) yielded significant bacteriuria. The most common bacterium isolated was Staphylococcus aureus (29.6%) followed closely by Escherichia coli (28.7%) both of which were highest during the second trimester of gestation. We isolated 152 gram-negative isolates with 41.4% (63/230) being + ESBL. Of the 63 + ESBL, 45 (71.4%) possessed bla_TEM, 42 (66.7%) had bla_CTX-M and 2 (3.2%) possessed bla_SHV genes; 38 possessed multiple ESBL genes comprising 2 with both SHV and TEM genes and 36 with both CTX-M and TEM genes.

Conclusion

High prevalence of UTI and persistent transmission of ESBLs among pregnant women in the Ho Municipality is worrying and a course for public health concern. We recommend urine culture during pregnancy as a routine laboratory investigation to avoid birth-related complications.

Molecular Characterization of Gene-Mediated Resistance and Susceptibility of ESKAPE Clinical Isolates to Cistus monspeliensis L. and Cistus salviifolius L. Extracts

Background

Multidrug resistance (MDR) and extensively drug-resistant (XDR) are now the biggest threats to human beings. Alternative antimicrobial regimens to conventional antibiotic paradigms are extensively searched. Although Cistus extracts have long been used for infections in traditional folk medicines around the world, their efficacy against resistant bacteria still needs to be elucidated. We aim to investigate the antibiotic susceptibility profiles of clinical strains Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae (acronym “ESKAPE”), and their resistance mechanisms by PCR, as well as their sensitivity to C. monspeliensis (CM) and C. salviifolius (CS) methanol extracts and their fractions.

Methods

Antibiotic susceptibility profile and resistance mechanism were done by antibiogram and PCR. Fractions of CM and CS were obtained using maceration and Soxhlet; their antibacterial activities were evaluated by determining inhibition zone diameter (IZD), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC).

Results

Results revealed that all strains were XDR except S. aureus, which was MDR. The PCR indicates the presence of gene-mediated resistance (bla_CTX-M, bla_SHV, bla_OXA-48, bla_NDM, bla_OXA-51, bla_OXA-58, bla_IMP, bla_VIM, and bla_mecA). Also, maceration was slightly better for bioactivity preservation. Overall, the extracts of CM (IZD = 20 mm, MIC = 0.01 mg/mL) were more active than those of CS. All extracts inhibited MRSA (methicillin-resistant Staphylococcus aureus) and ERV (Enterococcus faecium Vancomycin-Resistant) with interesting MICs. The ethyl acetate fraction manifested great efficacy against all strains. Monoterpene hydrocarbons and sesquiterpenes oxygenated were the chemical classes of compounds dominating the analyzed fractions. Viridiflorol was the major compound in ethyl acetate fractions of 59.84% and 70.77% for CM and CS, respectively.

Conclusions

The superior activity of extracts to conventional antibiotics was seen for the first time in the pathogens group, and their bactericidal effect could be a promising alternative for developing clinical antibacterial agents against MDR and XDR ESKAPE bacteria.

Evaluation of Citrus reticulata essential oil: Chemical composition and antibacterial effectiveness incorporated gelatin on E. coli and S. aureus

In the present study, we evaluated the antibacterial activity of Citrus reticulata (C. reticulata) essential oil-incorporated gelatin film solution against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The minimum inhibitory concentration (MIC) of C. reticulata essential oil (CrEO) on E. coli and S. aureus were found to be 10.1 and 9.1 mg mL^-1, respectively, using spectrophotometric microdilution technique. The antimicrobial effect of CrEO alone and incorporated gelatin-based film solutions (CrEO-F) against these pathogens were determined by the disc diffusion method. While the inhibition zones of CrEO were 2.4 mm and 10.05 mm, CrEO-F was reported as 1.5 and 7.8 mm against E. coli and S. aureus, respectively. These findings demonstrated that the CrEO can compete with coating agents with antimicrobial additives and it can find a place in the application areas. Besides, the chemical composition of the CrEO was determined by GC-MS.

Beta-lactamase resistance genes in Enterobacteriaceae from Nigeria

Background

Beta-lactamase genes are one of the most important groups of antimicrobial resistance genes in human and animal health. Therefore, continuous surveillance of this group of resistance genes is needed for a better understanding of the local epidemiology within a country and global dissemination.

Aim

This review was carried out to identify different beta-lactamase resistance genes reported in published literature from Nigeria.

Methods

Systematic review and meta-analysis was carried out on eligible Nigerian articles retrieved from electronic literature searches of PubMed^®, African Journals Online, and Google Scholar published between January 1990 and December 2019. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses method was adopted to facilitate clarity and transparency in reporting review findings.

Results

Fifty-seven articles were included. All beta-lactamases reported were detected from Gram-negative bacteria, particularly from Enterobacteriaceae. Thirty-six different beta-lactamase genes were reported in Nigeria. These genes belong to the narrow-spectrum, AmpC, extended-spectrum and carbapenemase beta-lactamase resistance genes. The pooled proportion estimate of extended-spectrum beta-lactamase genes in Nigeria was 31% (95% confidence interval [CI]: 26% – 36%, p < 0.0001), while the estimate of the bla_CTX-M-15 gene in Nigeria was 46% (95% CI: 36% – 57%, p < 0.0001). The proportion estimate of AmpC genes was 32% (95% CI: 11% – 52%, p < 0.001), while the estimate for carbapenemases was 8% (95% CI: 5% – 12%, p < 0.001).

Conclusion

This study provides information on beta-lactamase distribution in Nigeria. This is necessary for a better understanding of molecular epidemiology of clinically important beta-lactamases, especially the extended-spectrum beta-lactamases and carbapenemases in Nigeria.

Molecular characterization of invasive Enterobacteriaceae from pediatric patients in Central and Northwestern Nigeria

Background

Bacteremia is a leading cause of mortality in developing countries, however, etiologic evaluation is infrequent and empiric antibiotic use not evidence-based. Here, we evaluated the patterns of ESBL resistance in children enrolled into a surveillance study for community acquired bacteremic syndromes across health facilities in Central and Northwestern Nigeria.

Method

Blood culture was performed for children aged less than 5 years suspected of having sepsis from Sept 2008-Dec 2016. Blood was incubated using the BACTEC^00AE system and Enterobacteriacea identified to the species level using Analytical Profile Index (API20E^®). Antibiotic susceptibility profile was determined by the disc diffusion method. Real time PCR was used to characterize genes responsible for ESBL production.

Result

Of 21,000 children screened from Sept 2008-Dec 2016, 2,625(12.5%) were culture-positive. A total of 413 Enterobacteriaceae available for analysis were screened for ESBL. ESBL production was detected in 160 Enterobacteriaceae, high resistance rates were observed among ESBL-positive isolates for Ceftriaxone (92.3%), Aztreonam (96.8%), Cefpodoxime (96.3%), Cefotaxime (98.8%) and Trimethoprim/sulfamethoxazole (90%), while 87.5%, 90.7%, and 91.9% of the isolates were susceptible to Imipenem, Amikacin and Meropenem respectively. Frequently detected resistance genes were blaTEM—83.8% (134/160), and, blaCTX-M 83.1% (133/160) followed by blaSHVgenes 66.3% (106/160). Co-existence of blaCTX-M, blaTEM and blaSHV was seen in 94/160 (58.8%), blaCTX-M and blaTEM in 118/160 (73.8%), blaTEM and blaSHV in 97/160 (60.6%) and blaCTX-M and blaSHV in 100/160 (62.5%) of isolates tested.

Conclusion

Our results indicate a high prevalence of bacteremia from ESBL Enterobacteriaceae in this population of children. These are resistant to commonly used antibiotics and careful choice of antibiotic treatment options is critical. Further studies to evaluate transmission dynamics of resistance genes could help in the reduction of ESBL resistance in these settings.

Occurrence of Multidrug-resistant Uropathogens Implicated in Asymptomatic Bacteriuria in Adults with Sickle Cell Disease in Ile-Ife, Southwest Nigeria

OBJECTIVES

We sought to determine the prevalence of asymptomatic bacteriuria (ASB) in patients with sickle cell disease (SCD), the susceptibility profile of its agents and their extended-spectrum β-lactamase (ESBL) production.

METHODS

Fifty-nine patients with SCD and 116 healthy controls were investigated. Urine samples were collected and cultured by standard techniques. We used the disc diffusion technique to determine antibiotic susceptibility. ESBL was detected by the combination disc method and detection of bla SHV, bla TEM, and bla CTX-M genes by multiplex-polymerase chain reaction.

RESULTS

The prevalence of ASB was higher among patients with SCD (8.6%) than controls (0.9%) (p = 0.016), predominantly among females. Coagulase-negative staphylococci (n = 2; 33.3%) predominated among the isolates. Other uropathogens included Stenotrophomonas maltophilia, Acinetobacter baumannii, and Enterobacter cloacae. All isolates were sensitive to meropenem but were resistant to ceftazidime, ampicillin, and tetracycline. bla SHV, bla TEM, and bla CTX-M-15 were detected in Enterobacter cloacae.

CONCLUSIONS

The prevalence of ASB is high in patients with SCD predominantly among females. Rare multidrug-resistant uropathogens were implicated. We posit a need for resistance surveillance programs and antibiotic stewardship to prevent treatment failure and reduce drug resistance.

The burden of extended-spectrum β-lactamase-producing Enterobacteriaceae in Nigeria: a systematic review and meta-analysis

Antibiotic resistance on account of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) has become a major public health concern in developing countries. The presence of ESBL-PE is associated with increased morbidity, mortality and healthcare costs. There is no active antimicrobial surveillance mechanism in Nigeria. The aim of this study is to determine a precise estimate of the burden of ESBL-PE in Nigeria. We employed Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and searched electronic databases for suitable studies. We derived pooled prevalence estimates using random effects models and assessed trends with meta-regression. We found 208 studies, with 38 satisfying our inclusion criteria. The overall pooled prevalence of ESBL-PE in Nigeria was 34.6% (95% CI 26.8 to 42.3%) and increased at a rate of 0.22% per year (p for trend=0.837). In summary, we found the prevalence of ESBL-PE in Nigeria to be high and recommend a robust national survey to provide a more detailed picture of the epidemiology of ESBL-PE in Nigeria.

Molecular detection and antibiotic resistance pattern of extended-spectrum beta-lactamase producing Escherichia coli in a Tertiary Hospital in Enugu, Nigeria

BACKGROUND

The use of antibiotic agents in the treatment of infectious diseases has greatly contributed to the decrease in morbidity and mortality, but these great advances in treatment are being undermined by the rapidly increasing antimicrobial resistant organisms. Extended-spectrum beta-lactamases are enzymes hydrolyzing the beta lactam antibiotics, including third generation cephalosporins and monobactams but not cephamycins and carbapenems. They pose a serious global health threat and have become a challenge for health care providers. The aim of this research was to assess the prevalence of extended-spectrum beta-lactamase producing Escherichia coli in University of Nigeria Teaching Hospital Ituku-Ozalla Enugu and to detect the risk factors for acquisition of the resistant organism. To proffer advice on antibiotic stewardship in clinical practice and public health interventions, to curb the spread of the resistant organisms in the hospital.

RESULTS

Out of the 200 E. coli isolates, 70 (35.00%) were confirmed positive for extended-spectrum beta-lactamase production. Fifty-three (75.7%) were from hospital acquired infections. All the isolates were resistant to ampicillin, tetracycline and chloramphenicol while 68 (97.14%) of the 70 isolates were susceptible to imipenem. BlaTEM, blaSHV and blaTEM were detected in 66 (94%) of the 70 isolates. The ESBL bla genes detected were blaCTX-M (n = 26; 37.14%), blaTEM (n = 7; 10.00%), blaSHV (n = 2; 2.86%), blaCTX-M/TEM (n = 7; 10.0%), blaCTX-M/SHV (n = 14; 20.0%) and blaCTX-M/TEM/SHV (n = 10; 14.29%). The three bla genes were not detected in 4 (5.71%) of the isolates. Recent surgery, previous antibiotic and intensive care unit admission were the associated risk factors to infections caused by extended-spectrum beta-lactamase producing E. coli.

CONCLUSION

There is a high rate of infections caused by extended-spectrum beta-lactamase producing E. coli. Recent surgery, previous antibiotic and intensive care unit admission were associated risk factors.

Multi-Antibiotic Resistance and Factors Affecting Carriage of Extended Spectrum β-Lactamase-Producing Enterobacteriaceae in Pediatric Population of Enugu Metropolis, Nigeria

Extended-spectrum β-lactamase (ESBL)-producing organisms have become a serious challenge in healthcare delivery globally. The prevalence of ESBL carriage in healthy and sick children in Enugu, Nigeria, was bacteriologically investigated in this study. Four hundred and twenty-two biological samples (mid-stream urine and feces) were bacteriologically analyzed. The isolates were screened for ESBL production using Clinical and Laboratory Standards Institute (CLSI) breakpoints. The suspected ESBL producers were confirmed using double disc synergy test method. Out of the 162 isolates screened, 32 (19.8%) were confirmed as ESBL positive, with a prevalence of 25.32% among sick children in Enugu State University Teaching Hospital (ESUTH), Parklane, Enugu and 13.89% in apparently healthy children in a community setting. Klebsiella spp. and Escherichia coli had the highest prevalence of 34.6% and 28.6%, respectively; Citrobacter spp. and Enterobacter spp. were 18.2% and 16.7%, respectively. The ESBL positive isolates were resistant to sulfamethoxazole/trimethoprim (100%), tetracycline (100%), kanamycin (96.9%), nitrofurantoin (84.4%), ciprofloxacin (68.6%), and chloramphenicol (62.5%) but susceptible to meropenem (100%), colistin (56.3%), and gentamicin (50%). Klebsiella spp. had the highest ESBL occurrence among sick children while E. coli had the highest ESBL occurrence among healthy children in Enugu. All ESBL-positive isolates were multiply resistant to conventional antibiotics. The emergence and spread of β-lactamase-producing Enterobacteriaceae in hospital and community environments highlight the possibility for an infection outbreak if not checked.

A comparative study for detection of extended spectrum β-lactamase (ESBL) production by Enteroaggregative Escherichia coli (EAEC) strains using double disc, nitrocefin and PCR assays

We explored and evaluated for the first time colorimetric nitrocefin assay in conjunction with the double disc test and PCR assay. We suggested the use of nitrocefin assay for rapid screening of ESBL-production by Enteroaggregative Escherichia coli.

Multi-antibiotic resistant extended-spectrum beta-lactamase producing bacteria pose a challenge to the effective treatment of wound and skin infections

Introduction

The increasing incidence of antibiotic resistant bacteria is a concern both to the clinicians and the patients due to obvious consequences such as treatment failures, prolonged patients’ stay in hospital and nosocomial infections. The choice of the first antibiotic therapy in emergency wards in hospitals is usually not based on patient-specific microbial culture and susceptibility test result.This study is aimed at profiling extended-spectrum beta-lactamase (ESBL) producing bacteria associated with wound injuries and highlighting their multi-antibiotic resistance character.

Methods

Sixty-three wound swab samples were collected and cultured on nutrient agar and on selective media. Evaluation for ESBL production was by phenotypic method while the antibiogram screening was by disc-diffusion.

Results

The wounds evaluated were diabetic sore (14), cancer wounds (12), surgical wounds (17), wounds due to road traffic accidents (10) and wounds from fire burn (10). The result showed that 61 wounds were infected and the prevalence of the infecting pathogens was Escherichia coli 17.46%, Klebsiella Pneumonia 14.28%, Salmonella typhi 12.79%, Pseudomonas Aeruginosa 34.92% and Staphylococcus aureus 17.46%. Thirty four (55.74 %) isolates were ESBL producers, greater than 50% of which being Pseudomonas Aeruginosa. The antibiogram study of the ESBL producers showed multi-drug resistance with resistance highest against ampicillin (100%), followed by cephalosporins: cefuroxime (94.12%) and ceftriaxone (61.76%). No resistance was recorded against the β-lactamase inhibitors: amoxicillin/clavulanate and ceftriaxone/sulbactam. There was a high incidence (55.74 %) of ESBL-producing microbes in the wounds. The isolates were mostly multi-antibiotic resistant.

Conclusion

Multi-drug resistant ESBL-producing bacteria are common in wound infections in the community. However, amoxicillin/clavulanate or ceftriaxone/sulbactam may be used to treat most patients with such infections in the hospital. This may guide antibiotic selection and use in trauma, most especially in resource limited countries where laboratory test is unaffordable for a majority of patients.

Genetic characterization of TEM-type ESBL-associated antibacterial resistance in Enterobacteriaceae in a tertiary hospital in Ghana

BACKGROUND

Antibiotic resistance due to the presence of extended-spectrum beta-lactamases (ESBLs) among Enterobacteriaceae is a worldwide problem. Data from Ghana regarding this resistance mechanism is limited. This study was designed to investigate the presence of TEM-type ESBL genes, their locations and their conjugabilities in clinical isolates of enterobacteria collected from the Korle-Bu Teaching Hospital in Ghana.

METHODS

Study isolates were characterized with respect to ESBL phenotype, TEM-type ESBL gene detection, location of the ESBL gene(s) and conjugability of the ESBL phenotype using nalidixic acid-resistant Escherichia coli K-12 as recipient. Phenotyping was by Kirby Bauer disk diffusion using cefpodoxime, ceftazidime, cefotaxime and their combinations with clavulanate. Gene detections were by PCR using blaTEM primers.

RESULTS

Overall, 37.96 % of 137 clinical isolates showed ESBL phenotype. The ESBLs occurred mostly in Klebsiella spp. (42.3 %) and then Escherichia coli (34.6 %). The TEM gene was detected in 48.1 % of ESBL-positive isolates and was determined to be plasmid-borne in 24 of 25 blaTEM detections. Overall, 62.7 % of TEM-producing isolates transferred the ESBL phenotype by conjugation.

CONCLUSIONS

The results highlight the presence of TEM-type ESBLs in the Korle-Bu Teaching Hospital and show considerable risk of environmental contamination through the urine of infected persons. An inhibition zone chart was generated which indicates the possible presence of complex beta-lactamase types. The data points to the fact that the ESBL-producing bacteria may disseminate this resistance mechanism via conjugation.

Predictors of blaCTX-M-15 in varieties of Escherichia coli genotypes from humans in community settings in Mwanza, Tanzania

BACKGROUND

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae commonly cause infections worldwide. Bla CTX-M-15 has been commonly detected in hospital isolates in Mwanza, Tanzania. Little is known regarding the faecal carriage of ESBL isolates and bla CTX-M-15 allele among humans in the community in developing countries.

METHODS

A cross-sectional study involving 334 humans from the community settings in Mwanza City was conducted between June and September 2014. Stool specimens were collected and processed to detect ESBL producing enterobacteriaceae. ESBL isolates were confirmed using disc approximation method, commercial ESBL plates and VITEK-2 system. A polymerase chain reaction and sequencing based allele typing for CTX-M ESBL genes was performed to 42 confirmed ESBL isolates followed by whole genome sequence of 25 randomly selected isolates to detect phylogenetic groups, sequence types plasmid replicon types.

RESULTS

Of 334 humans investigated, 55 (16.5 %) were found to carry ESBL-producing bacteria. Age, history of antibiotic use and history of admission were independent factors found to predict ESBL-carriage. The carriage rate of ESBL-producing Escherichia coli was significantly higher than that of Klebsiella pneumoniae (15.1 % vs. 3.8 %, p = 0.026). Of 42 ESBL isolates, 37 (88.1 %) were found to carry the bla CTX-M-15 allele. Other transferrable resistance genes were aac(6')Ib-cr, aac(3)-IIa, aac(3)-IId, aadA1, aadA5, strA, strB and qnrS1. Eight multi-locus sequence types (ST) were detected in 25 E. coli isolates subjected to genome sequencing. ST-131 was detected in 6 (24 %), ST-38 in 5 (20 %) and 5 (20 %) clonal complex - 10(ST-617, ST-44) of isolates. The pathogenic phylogenetic groups D and B2 were detected in 8/25 (32 %) and 6/25 (24 %) of isolates respectively. BlaCTX-M-15 was found to be located in multiple IncY and IncF plasmids while in 13/25(52 %) of cases it was chromosomally located.

CONCLUSION

The overlap of multi-drug resistant bacteria and diversity of the genotypes carrying CTX-M-15 in the community and hospitals requires an overall approach that addresses social behaviour and activity, rationalization of the antibiotic stewardship policy and a deeper understanding of the ecological factors that lead to persistence and spread of such alleles.

Characterization of Extended-Spectrum Beta-lactamase from Escherichia coli and Klebsiella Species from North Eastern Nigeria

INTRODUCTION

Resistance to antimicrobials has become a serious global health concern complicating treatment strategies and increasing health-care costs. The extended-spectrum beta-lactamase producing bacteria stand out as bacteria of great epidemic concern among Gram negative bacilli. Control and appropriate interventions for antimicrobial resistance depend on effective surveillance and knowledge of the patterns and determinants of resistance.

AIM

The present study was undertaken to detect and characterize ESBLs in Escherichia coli and Klebsiella Species from University of Maiduguri Teaching Hospital, Maiduguri, North-Eastern Nigeria.

MATERIALS AND METHODS

Confirmed variants of Escherichia coli and Klebsiella Species isolated from 439 patients that were admitted in various units of University of Maiduguri Teaching Hospital (UMTH) were screened for ESBL using CLSI breakpoints. Suspected ESBLs producers were subjected to confirmation using double disk synergy method. Detection of ESBL genes was further done by multiplex PCR.

RESULTS

Out of the 439 isolates screened; the result shows 147 (33.5%) were ESBL producers but only 121(23.6%) were confirmed by the double disk synergy method. The prevalence of ESBL amongst the organisms were; 41/172 (23.8%) for Escherichia coli and 80/267/(30.0%) for Klebsiella Species. Based on PCR analysis, the various percentage genotypes of the ESBL producers were 44 (36.4%) for SHV gene followed by 38(31.4%) for TEM gene and the lowest of 33(27.3%) for CTX-M gene.

CONCLUSION

ESBLs are prevalent among Species of Escherichia coli and Klebsiella Species in Maiduguri, Borno State, not only are there TEM and SHV but also CTX-M types. Antibiotic stewardship program to maximise use of available antibiotics is underscored as well as coordinated national efforts in combating resistance.

bla CTX-M-I group extended spectrum beta lactamase-producing Salmonella typhi from hospitalized patients in Lagos, Nigeria

Purpose

The global spread of bla_CTX-M-I extended-spectrum beta-lactamase (ESBL)-producing Salmonella spp. remains a major threat to treatment and control. Evidence of emergence and spread of this marker are lacking in Nigeria. This study investigated bla_CTX-M-I ESBL production among Salmonella isolates from hospitalized patients.

Methods

Patients (158 total) made up of two groups were evaluated. Group A was composed of 135 patients with persistent pyrexia and group B was composed of 23 gastroenteritis patients and their stool samples. Samples were cultured, and isolates were identified and were subjected to antibiotic susceptibility testing by standard methods. Isolates were further screened for ESBL production, bla_CTX-M-I genes and transferability by double disk synergy test, plasmid extraction, polymerase chain reaction, and conjugation experiment.

Results

Thirty-five (25.9%) Salmonella isolates were identified from group A, of which 74.3% were S. typhi, 22.9% were S. paratyphi and two (5.7%) were invasive non-typhoidal S. enteritidis. Nine Plasmodium falciparum infections were recorded, four of which were identified as co-infections with typhoidal Salmonella. Only two (8.7%) S. enteritidis samples were obtained from group B (P>0.05). A total of 24 isolates were ESBL-positive, eliciting resistance to five to seven antibiotics, and were multiple-drug resistant. ESBL production due to the bla_CTX-M-I gene cluster was detected in eleven (45.8%) Salmonella isolates. Nine (81.8%) of the eleven bla_CTX-M-I ESBL producers were S. typhi and two (18.2%) isolates were S. enteritidis. Four of nine S. typhi bla_CTX-M-I ESBL-producing strains harbored 23 kb self-transmissible plasmid that was co-transferred with cefotaxime and augmentin resistance to Escherichia coli j53-2 transconjugants.

Conclusion

This study revealed the emergence of bla_CTX-M-IS. typhi as an agent of persistent pyrexia with potential to spread to other Enterobacteriaceae in Lagos, Nigeria. Cautionary prescription and judicious use of third-generation cephalosporins, particularly cefotaxime, for the treatment of typhoid fever and routine screening for P. falciparum co-infection with ESBL-producing Salmonella in the laboratories during diagnosis of persistent pyrexia conditions in patients are recommended.

Abattoirs as non-hospital source of extended spectrum beta lactamase producers: confirmed by the double disc synergy test and characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry

In this study, the presence of extended spectrum beta lactamase (ESBL) producing organisms in abattoirs, a non-hospital community was investigated. The presence of ESBL-producing phenotypes was confirmed by the Double Disc Synergy Test (DDST). Out of the 99 isolates screened for ESBL, 28 (28.3%) were confirmed positive. The positive isolates were characterised by using Matrix-Assisted Laser Desorption/Ionization Time of flight Mass Spectrometry. 50% of the isolates were Pseudomonas spp., the rest were different species of Acinetobacter, Stenotrophomonas and Achromobacter. Pseudomonas monteilli and Pseudomonas putida were the most occurring in the intestine. The entire positive ESBL producers were subjected to plasmid curing to ascertain the location of the resistant marker. The result of the plasmid curing indicated that the resistant genes were chromosomally borne. The findings have therefore established the presence of ESBL producing organisms in the gut of animals from abattoirs and the table were the meat are sold, and its rate of occurrence is comparable to hospital ICUs. Abattoir communities could probably be a source of human infection with ESBL expressing pathogens and possible transfer to non-ESBL producers.

A Multicenter Study of Beta-Lactamase Resistant Escherichia coli and Klebsiella pneumoniae Reveals High Level Chromosome Mediated Extended Spectrum β Lactamase Resistance in Ogun State, Nigeria

As a result of the ever increasing problem of multiresistant bacteria, we instituted a surveillance program with the aim of identifying the basic molecular properties of ESBL in our environment. About 197 isolates of Escherichia coli and Klebsiella pneumoniae were selected and tested for ESBL production and antimicrobial susceptibility. Plasmid profiles were determined and curing ability was tested. ESBL prevalence was 26.4% for all isolates tested, with E. coli having a greater proportion. There was absolute resistance to ampicilin, tetracycline, and co-trimaxole among tested isolates. There was above average susceptibility to the 2nd and 3rd generation cephalosporins. Plasmid profiles of tested isolates ranged from 9 kbp to 26 kbp with average of 14.99 ± 2.3 kbp for E. coli and 20.98 ± 1.8 kbp K. pneumoniae, 9.6% of ESBL positive E. coli plasmids were cured, while 3.9% of K. pneumoniae plasmids were cured after treatment. The present study shows an upsurge in ESBL acquisition by gram negative bacteria and evidence of cocirculation of varying subtypes of ESBL with both plasmid transmissible and chromosome encoded subtypes. This calls for universal surveillance and more effort towards molecular epidemiology of this public health treatment.

Phenotypic characterization of ESBL producing Enterobacter cloacae among children

Objective: The emergence of ESBL producing Enterobacter cloacae in clinical isolates is posing a serious threat for treating nosocomial infections. The aim of the study was to determine the frequency of extended spectrum β-lactamase (ESBL) producing Enterobacter cloacae and to compare the phenotypic methods used for the characterization of ESBL producing strains.

Methodology: This cross sectional observational study was conducted during April 2011 to March 2012 at Microbiology department of The Children’s Hospital and Institute of Child Health, Lahore. A total number of 20,257 various clinical samples were analyzed during the study period. Enterobacter cloacae were identified using API 20E system and ESBL detection was carried out using double-disk synergy test (DDST) and CLSI confirmatory test.

Results:Enterobacter cloacae were isolated from 221 samples, out of which 33 (14.93%) were ESBL producers and 188 (85.07%) were non-ESBL producers. The gender distribution of ESBL producing Enterobacter cloacae was 21 (63.6%) in males and 12 (36.4%) in females. Highest frequency (63%) of ESBL producing Enterobacter cloacae was detected in blood samples. Comparison of DDST and CLSI confirmatory test showed that 25 (75.75%) isolates were characterized by DDST and 33 (100%) using CLSI confirmatory test.

Conclusion: The present study shows moderately high frequency of ESBL producing Enterobacter cloacae among children. DDST was found to be less efficient in ESBL detection as compared to CLSI confirmatory test.

First description of Escherichia coli producing CTX-M-15- extended spectrum beta lactamase (ESBL) in out-patients from south eastern Nigeria

We studied the presence of extended spectrum beta lactamases (ESBLs) in 44 clinical isolates of Escherichia coli collected from out-patients in two university teaching hospitals in South-Eastern Nigeria. Species identification was performed by standard microbiology methods and re-confirmed by MALDI-TOF technology. Phenotypic characterization of ESBL enzymes was done by double disc synergy test and presence of ESBL genes was determined by specific PCR followed by sequencing. Transfer of plasmid DNA was carried out by transformation using E. coli DH5 as recipient strain. Phenotypic characterization identified all isolates to be ESBL positive. 77% of strains were from urine, 13.6% from vaginal swabs and 9.0% from wound swabs. 63.6% were from female patients, 68% were from outpatients and 95.5% from patients younger than 30 years. All ESBL producers were positive in a PCR for bla_CTX-M-1 cluster, in exemplary strains bla_CTX-M-15 was found by sequencing. In all strains ISEcp1 was found upstream and ORF477 downstream of bla_CTX-M. PCR for bla_TEM and bla_OXA-1 was positive in 93.1% of strains, whereas bla_SHV was not detected, aac(6′)-Ib-cr was found in 97.7% of strains. RAPD analysis revealed seven different clonal groups named A through G with the majority of the strains (65.9%) belonging to clone A. Transfer of an ESBL plasmid with co-resistance to gentamicin, kanamycin, tobramycin, doxycycline and trimethropim-sulfamethoxazole was successful in 19 (43.2%) strains. This study showed a high rate of CTX-M-1 cluster - ESBLs in South-Eastern Nigeria and further confirms the worldwide spread of CTX-M ESBL in clinical isolates.

Prolonged febrile illness due to CTX-M-15 extended-spectrum β-lactamase-producing Klebsiella pneumoniae infection in Nigeria

We report on an 8-year-old patient with septicaemia unresponsive to therapy for five weeks. Undetected, extended-spectrum β-lactamase (ESBL) production by the infecting Klebsiella strain was regarded as responsible for treatment failure. Intravenously administered imipenem during the sixth week led to sustained resolution of fever. Resource-limited hospitals can incur prohibitive costs from ESBL-producer infections because of diagnostic limitations and consequent treatment failure involving prolonged supportive therapy.

Polymicrobial necrotizing fasciitis involving enterobacteria producing CTX-M-15 extended-spectrum β-lactamases

Necrotizing fasciitis due to multiple Gram-negative organisms in a Nigerian patient is described. Morganella morganii and Citrobacter freundii carrying the CTX-M-15 extended-spectrum β-lactamase gene were isolated, highlighting the emergence of this β-lactamase in Western Africa and its successful spread amongst a wider range of members of the Enterobacteriaceae.

Characterization of ESBL (SHV-12) producing clinical isolate of Enterobacter aerogenes from a tertiary care hospital in Nigeria

Background

We studied the beta-lactamases of an E. aerogenes isolate recovered from the blood of a two-year-old patient. The isolate demonstrated a disk-diffusion phenotype typical for an AmpC-ESBL co-producer.

Methods

Microbiology studies were performed according to standard protocols. The resistance gene was identified by transconjugation and cloning experiments.

Results

By transconjugation only a narrow spectrum beta-lactamase (TEM-1) encoded on a small plasmid was transmitted. The ESBL was cloned and expressed in an E. coli host. Sequence analysis of the recombinant plasmid revealed bla_SHV-12 associated to the insertion sequence, IS26.

Conclusion

This is the first study demonstrated the occurrence of SHV-12 in Nigeria.

In vitro antimicrobial activity of crude extracts from plants Bryophyllum pinnatum and Kalanchoe crenata

Extracts from the leaves of Bryophyllum pinnatum and Kalanchoe crenata were screened for their antimicrobial activities. Solvents used included water, methanol, and local solvents such as palmwine, local gin (Seaman's Schnapps 40% alcoholic drink,) and "omi ekan-ogi" (Sour water from 3 days fermented milled maize). Leaves were dried and powdered before being soaked in solvents for 3 days. Another traditional method of extraction by squeezing raw juice from the leaves was also employed. All extracts were lyophilized. These extracts were tested against some gram-negative organisms (Escherichia coli ATCC 25922, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Shigella flexneri, Salmonella paratyphi, Citrobacter spp); gram-positive organisms Staphylococcus aureus ATCC 25213, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis) and a fungus (Candida albicans). Agar well diffusion and broth dilution methods were used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) at concentrations of 512 mg/ml to 4 mg/ml. All the organisms except Candida albicans were susceptible to the extracts obtained from the traditional method. The squeezed-leaf juice of Kalanchoe crenata was the most active one with MIC of 8 mg/ml against Pseudomonas aeruginosa, Klebsiella pneumoniae and Bacillus subtilis, 32 mg/ml against Shigella flexneri, 64 mg/ml against Escherichia coli and 128 mg/ml against the control strain Staphylococcus aureus while its MBC is 256 mg/ml against these organisms except Bacillus subtilis and Klebsiella pneumoniae. The gram-positive organisms were more sensitive to the methanol and local gin-extract of Bryophyllum pinnatum. Extracts from other solvents showed moderate to weak activity.

Evaluation of the antimicrobial properties of different parts of Citrus aurantifolia (lime fruit) as used locally

We investigated the potency of Citrus aurantifolia (Lime fruit), against pathogens, in the different forms in which this fruit plant is used locally (juice of the fruit, burnt rind of the fruit commonly known as "epa-ijebu" in the Yoruba dialect) and the oil obtained from steam distillation of the fruit. The antimicrobial activity of "epa-ijebu" in different solvents was also compared. The solvents include palm-wine (a local alcoholic drink tapped from palm trees), Seaman's Schnapps 40% alcoholic drink, water, ethanol and fermented water from 3 days soaked milled maize known as "ekan-ogi" or "omidun" in the Yoruba dialect. Antimicrobial activity was carried out by the agar well diffusion. The clinical isolates used included Anaerobic facultative bacteria, namely: Staphylococcus aureus ATCC 25213, Staphylococcus aureus, Salmonella paratyphi, Shigella flexnerii, Streptococcus faecalis, Citrobacter spp, Serratia spp, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli ATCC 25922, and Escherichia coli; Fungi such as Aspergillus niger and Candida albicans; and Anaerobes which includes Bacteroides spp, Porphyromonas spp, and Clostridium spp. Crude extracts of all solvents used varied in zones of inhibition. The anaerobes and the gram-positive bacteria were susceptible to all the extracts with minimum inhibitory concentration (MIC) ranging from 32 mg/ml-128 g/ml. The activity against the fungi showed only the oil extract potent for A. niger, while Candida albicans was susceptible to all the extracts with MIC ranging from 256 mg/ml-512 mg/ml. The gram-negatives have MIC ranging from 64 mg/ml-512 mg/ml. Minimum bactericidal concentration (MBC) ranged between 32 mg/ml to 512 mg/ml depending on isolates and extracting solvent. The oil and palm-wine extract of "epa-ijebu" showed greater activity than the other extracts. The killing rate of the schnapps extract on S. aureus and E. coli was 1 and 3.5 hours respectively.

Prevalence of extended-spectrum β-lactamases in isolates of the Enterobacter cloacae complex from German hospitals

In 2002, 119 isolates of the Enterobacter cloacae complex were collected randomly from 11 German laboratories nationwide. Antibiotic susceptibilities were tested by disk-diffusion tests according to CLSI guidelines, and MICs were determined using Etests. PCRs were performed to amplify all TEM and SHV, and most CTX-M and OXA beta-lactamase genes. PCR products were sequenced to identify the precise extended spectrum beta-lactamase (ESBL) types. Isoelectric focusing (IEF) and PM/PML Etests were used to confirm production of the respective ESBLs. According to susceptibility tests and CLSI criteria, 49 (40%) isolates were resistant to extended-spectrum cephalosporins. Seven (5.8%) isolates were positive in at least one of the PCR assays. Sequencing identified production of TEM-1 beta-lactamase genes by three (2.9%) isolates, and ESBL genes of the CTX-M and SHV beta-lactamase families by five (4.2%) isolates. IEF confirmed the production of beta-lactamases in the expected pI ranges of the respective ESBLs, and four of the five ESBL-producers were detected using the PM/PML Etest. All ESBL-producing isolates showed co-resistance to sulphonamides.

Occurrence of extended spectrum beta-lactamase enzymes in clinical isolates of Klebsiella species from Harar region, eastern Ethiopia

Extended Spectrum beta-Lactamases (ESBLs) producer and multidrug resistant Klebsiella spp. are becoming a major nosocomial pathogen globally. There are no documented reports yet on the occurrence of ESBL enzymes in Klebsiella spp. species from Ethiopia. This study was undertaken to isolate and determine the occurrence of ESBLs and multi-drug resistant Klebsiella spp. in different clinical samples obtained from patients. A cross-sectional survey was conducted in four different hospitals of Harar region (Hiwot Fana, Misrak-Arbegnoch, Police and Army) from December 2003 to February 2004. Three hundred and eighty four clinical specimens (202 sputum, 164 urine and 18 pus) were collected from patients admitted in different wards. Antimicrobial susceptibilities were performed on 57 clinical isolates by standard disk diffusion procedures against eight antimicrobial agents. The ESBLs detection was made by using cefotaxime and ceftazidime alone and in combination with clavulanate. A total of 57 (15%) Klebsiella spp. were isolated from 384 patients. Of the 57 isolates, 33 (58%) were from sputum, 18 (31.5%) from urine and 6 (10.5%) from pus. Of the 57 Klebsiella spp., 54 (94.7%) were identified as K. pneumoniae and 3 (5.3%) as K. oxytoca. Resistance was found against cephalosporins [cefotaxime (39.0%), cefoxitin (39.0%), ceftazidime (40.0%), ceftriaxone (40.0%), cephalothin (42.0%)], chloramphenicol (70.0%), gentamicin (61.0%) and trimethoprim-sulphamethoxazole (65.0%). Analyzed Klebsiella isolates were characterized also by a high degree of multi-resistance (67.0%). In 19/57 (33.3%) of the Klebsiella isolates, ESBL production was detected. Rates of detection of ESBL producers were 42.1, 26.3, 26.3 and 5.3% in Hiwot-Fana, Misrak-Arbegnoch, Police and Army hospitals, respectively. Multi-drug resistant isolates were more prevalent among the ESBLs producers (95.0%) than non-producers (53.0%) (p=0.24). In conclusion, our results show that awareness of ESBL production by Klebsiella spp. is clinically important. In the absence of infection control measures, ESBL producing organisms readily pass horizontally from patient to patient. These strains also transiently colonize the hands of hospital staff members, thereby facilitating patient-to-patient transmission of the organism.

High rate of fatal cases of pediatric septicemia caused by gram-negative bacteria with extended-spectrum beta-lactamases in Dar es Salaam, Tanzania

Extended-spectrum beta-lactamases (ESBLs) were present in high proportions of Escherichia coli (25% [9 of 36]) and Klebsiella pneumoniae isolates (17% [9 of 52]) causing pediatric septicemia at a tertiary hospital in Tanzania. Patients with septicemia due to ESBL-producing organisms had a significantly higher fatality rate than those with non-ESBL isolates (71% versus 39%, P = 0.039). This is the first report of the CTX-M-15 genotype of ESBLs on the African continent and the first observation of SHV-12 genotype in an isolate of Salmonella enterica serotype Newport.

Risk factors associated with extended-spectrum β-lactamase-producing organisms at a tertiary care hospital

BACKGROUND

In 1995, beta-lactam inhibitor combinations replaced third-generation cephalosporins as empirical therapy in an effort to manage extended-spectrum beta-lactamase (ESBL) resistance. This study investigated the relationship between antibiotic usage and ESBL organisms from 1994 through 2002 using epidemiological and molecular analysis.

METHODS

A case-control study of 119 patients with ESBL organisms and 132 patients with non-ESBL organisms was conducted. Demographics, co-morbidities, device utilization and antibiotic use were analysed for all patients and infected patients only (cases = 75, controls = 83). Both exposure and degree of exposure (in grams) to antibiotics were included. A dot blot hybridization technique was used to identify genes in plasmid extracts from the ESBL organisms.

RESULTS

Ventilator days OR 1.1 (1.06, 1.15) P < 0.001, adult respiratory distress syndrome (ARDS) OR 3.1 (1.0, 9.7) P = 0.05, prior aminoglycoside use OR 2.7 (1.2, 6.1) P = 0.02, prior third-generation cephalosporin use OR 7.2 (2.6, 20) P < 0.001, and prior trimethoprim/sulfamethoxazole use OR 8.8 (3.1, 26) P < 0.001 were significantly associated with ESBL organisms by multivariate analysis. All models were concordant with a significant association of ventilator days, third-generation cephalosporins and trimethoprim/sulfamethoxazole with ESBL organisms. beta-Lactamase inhibitor combinations were not associated with ESBL organisms. Hybridization of plasmid extracts demonstrated that 95% of the ESBL organisms carried intI1, a mobile DNA element with a sulphonamide-resistance (R) gene and a frequent carrier of other R factors. Genes for specific types of trimethoprim-R and aminoglycoside-R were present in 26% and 40% of the extracts, respectively.

CONCLUSIONS

These data indicate that, besides patient risk factors and third-generation cephalosporins, other antibiotics may provide selective pressures in maintaining ESBL organisms due to multiple resistance genes on plasmids. beta-Lactamase inhibitor combinations appear to be an acceptable substitute to third-generation cephalosporins in strategies to control ESBL organisms.