Antimicrobial activity against gram negative bacilli from Yaounde Central Hospital, Cameroon

Antimicrobial susceptibility testing profiles of ESBL-producing Enterobacterales isolated from hospital and community adult patients in Blantyre, Malawi

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Extended-spectrum β-lactamase (ESBL) strains are an increasingly global health issue

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ESBL-Enterobacteriaceae isolates affected 64% of inpatients and 36% of outpatients

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ESBL-E isolates had high antimicrobial resistance; most were multi-drug resistant

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Surveillance systems are needed to monitor antimicrobial resistance in Malawi

Objective

There is a paucity of data on antimicrobial resistance (AMR) in Malawi. Here we present a study of AMR of extended-spectrum β-lactamases-producing Enterobacterales (ESBL-E) isolated from hospital and community settings in Blantyre, Malawi.

Design and Methods

A cross-sectional study was conducted between March and November 2020, involving 403 adult participants aged ≥18 years. Screening for ESBL-E was performed using CHROMagar ESBL medium. Production of ESBLs was confirmed by a combination disk test method. Antimicrobial susceptibility was tested using the agar disk diffusion method in accordance with the Clinical Laboratory Standards Institute's 2019 guidelines.

Results

The mean resistance rate of ESBL-E to antimicrobial agents tested was 49.2% (range from 1.4%–92%). The highest resistance rates were observed for trimethoprim-sulfamethoxazole (92%), amoxicillin and ceftriaxone (79%), doxycycline (75%) and gentamicin (72%). Carbapenems (meropenem and imipenem) were highly active against isolates. The overall rate of multi-drug resistant (MDR) ESBL-E was 47%. The highest MDR was found in Yersinia enterocolitica (51%) and the least in Serratia spp. (40%).

Conclusions

We found a high resistance rate of ESBL-E isolates to antimicrobial agents; the majority were MDR. Surveillance systems are recommended to monitor AMR in Malawi.

Molecular epidemiology of antibiotic-resistant genes and potent inhibitors against TEM, CTX-M-14, CTX-M-15, and SHV-1 proteins of Escherichia coli in district Peshawar, Pakistan

The Extended Spectrum Beta-Lactamases (ESBLs) producing bacteria is an issue of concern for clinicians resulting in minimize the treatment options. To overcome resistance mechanisms, novel inhibitors with good Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties must inhibit the ESBLs resistant genes. The current study aimed to identify the antibiotic resistance genes of ESBLs producing E. coli and a single inhibitor was designed to inhibit all the resistant proteins. The results showed that 42.9% ESBL producers had CTX-M (69.9%), TEM (63.4%), SHV (34.5%) and CTX-M-14 (17.5%) genes. The ESBLs producing isolates were resistant to cephalosporins, quinolones, and sulfonamide with Minimum Inhibitory Concentration (MICs) ranging from 64 to >256 μg/ml. To design multi inhibitory ligands, RECAP synthesis was used for the de-novo discovery of 1000 inhibitors database. Protein crystal structures were retrieved from Protein Data Base (PDB). Lipinski's rules of five were applied to the novel inhibitors database to improve the ADMET properties. The novel inhibitors database was selected for docking simulations. Placement of the ligand was used by the London dG algorithm implemented in Molecular Operating Environment (MOE), while GBVI/WSA dG algorithm was used for final refinement. Based on docking score, visual inspection of ligands interaction with key residues, binding affinity, and binding energy of ligands with proteins, ten compounds were selected for ESBLs proteins with best ADMET properties, binding energy, and binding affinity the reported ones. These hits compounds have unique scaffolds and are predicted to be a starting point for developing potent inhibitors against antibiotic-resistant proteins.

Trends of Antibacterial Resistance at the National Reference Laboratory in Cameroon: Comparison of the Situation between 2010 and 2017

Introduction

Antimicrobial resistance represents a growing public health threat. One of the World Health Organization's strategic objectives is “strengthening knowledge through surveillance and research.” Sub-Saharan African countries are still far from achieving this objective. We aimed to estimate and compare the prevalence of antibacterial resistance in 2010 and 2017 in Cameroon.

Methods

We conducted a retrospective study on all clinical specimens cultured in Centre Pasteur du Cameroun (CPC) in 2010 and 2017. Data were extracted from the CPC's laboratory data information system software and then managed and analyzed using R. Bacterial resistance rates were calculated in each year and compared using chi-square or Fisher's tests, and relative changes were calculated. Outcomes included acquired resistance (AR), WHO priority resistant pathogens, some specific resistances of clinical interest, and resistance patterns (multi, extensively, and pan drug resistances) for five selected pathogens.

Results

A total of 10,218 isolates were analyzed. The overall AR rate was 96.0% (95% CI: 95.4–96.6). Most of WHO priority bacterial resistance rates increased from 2010 to 2017. The most marked increases expressed as relative changes concerned imipenem-resistant Acinetobacter (6.2% vs. 21.6%, +248.4%, p = 0.02), imipenem-resistant Pseudomonas aeruginosa (13.5% vs. 23.5%, +74.1%, p < 0.01), 3rd generation-resistant Enterobacteriaceae (23.8% vs. 40.4%, +65.8%, p < 10⁻¹⁵), methicillin-resistant Staphylococcus aureus (27.3% vs. 46.0%, +68.6%, p < 0.002), fluoroquinolone-resistant Salmonella (3.9% vs. 9.5%, +142.9%, p = 0.03), and fluoroquinolone-resistant Enterobacteriaceae (32.6% vs. 54.0%, +65.8%, p < 10⁻¹⁵). For selected pathogens, global multidrug resistance was high in 2010 and 2017 (74.9% vs. 78.0% +4.1%, p = 0.01), intensively drug resistance rate was 5.8% (7.0% vs. 4.7%; p = 0.07), and no pan drug resistance has been identified.

Conclusion

Bacterial resistance to antibiotics of clinical relevance in Cameroon was high and appeared to increase between 2010 and 2017. There is a need for regular surveillance of antibacterial resistance to inform public health strategies and empirically inform prescription practices.

Frequency of Antimicrobial Resistance and Class 1 and 2 Integrons in Escherichia Coli Strains Isolated from Urinary Tract Infections

Resistance to antimicrobial compounds in E. coli strains is increasing. Integrons are mobile genetic elements that lead to the spread and transfer of antibiotic resistance genes in bacteria. The aim of the present study was to determine the frequency of class 1 and 2 integrons as well as the antimicrobial resistance in E.coli strains isolated from urinary tract infections (UTIs). A total of 100 clinical isolates of uropathogenic E. coli (UPEC) were collected from patients having UTIs. These strains were identified using biochemical tests. The antibiotic susceptibility patterns of the isolated bacteria were determined in accordance with the standard method recommended by the clinical and laboratory standards institute (CLSI). The presence of class 1 and 2 integrons was determined by PCR method. The most frequent antibiotic resistance was observed to ampicillin (72%), co-trimoxazole (66%), and nalidixic acid (62%). The highest sensitivity was seen to amikacine (11%) and gentamicin (20%). The multi-drug resistance (MDR) was observed in 80% of E. coli isolates. 70% and 3% of E. coli isolate possessed class 1 and 2 integrons, respectively. Our data suggest that the antimicrobial resistance to some antibiotics as well as the frequency of class 1 and 2 integrons is very high in E. coli strains. Moreover, class 1 integrons are correlated with resistance to ampicillin, gentamicin, ciprofloxacin, co-trimoxazole, and nalidixic acid. Therefore, it is very important to monitor integron-induced drug resistance, especially class 1 integron, in order to control the urinary tract infections causing by MDR E.coli strains.

Occurrence of blaTEM and blaCTXM Genes and Biofilm-Forming Ability among Clinical Isolates of Pseudomonas aeruginosa and Acinetobacter baumannii in Yaoundé, Cameroon

Background: Pseudomonas aeruginosa (PSA) and Acinetobacter baumannii (ACB) are non-fermentative bacteria mostly associated with nosocomial infections in humans. Objective: This study aimed to determine the antimicrobial resistance profiles and virulence gene of PSA and ACB previously isolated from humans in selected health facilities in Yaoundé, Cameroon. Methods: A total of 77 and 27 presumptive PSA and ACB isolates, respectively, were collected from the Yaoundé teaching hospital. These isolates were previously isolated from various samples including pus, blood and broncho-alveolar lavage. The identities of the isolates were determined through polymerase chain reaction (PCR) amplification of PSA and ACB specific sequences. Antimicrobial susceptibility testing (AST) was performed using the Kirby–Bauer disc diffusion method. Phenotypical expression of AmpC β-lactamases (AmpC), extended spectrum β-lactamases (ESBLs) and metallo β-Lactamases (MBLs) were determined using the combined disc method. Bacterial genomes were screened for the presence of β-lactamases bla_TEM and bla_CTXM genes using specific PCR. The pathogenicity of PSA and ACB was assessed through amplification of the lasB, exoA, pslA and exoS as well as OmpA and csuE virulence genes, respectively. Results: Of the 77 presumptive PSA isolates, a large proportion (75 to 97.4%) were positively identified. All (100%) of the presumptive 27 ACB harbored the ACB-specific ITS gene fragment by PCR. Twenty five percent of the PSA isolates produced ESBLs phenotypically while more than 90% of these isolates were positive for the lasB, exoA, pslA and exoS genes. A large proportion (88%) of the ACB isolates harboured the OmpA and csuE genes. bla_TEM and bla_CTXM were detected in 17 and 4% of PSA, respectively, while a much higher proportion (70 and 29%) of the ACB isolates possessed these resistance determinants respectively. Conclusion: Our findings reveal the occurrence of both virulence and drug-resistant determinants in clinical PSA and ACB isolates from patients in health care settings in Yaoundé, Cameroon, thus suggesting their role in the pathological conditions in patients.

Carriage of Extended-Spectrum-β-Lactamase- and AmpC-β-Lactamase-Producing Enterobacteriaceae (ESBL-PE) in Healthy Community and Outpatient Department (OPD) Patients in Nepal

Background

Extended-spectrum β-lactamase (ESBL)- and AmpC-β-lactamase (ESBL)- and AmpC-Enterobacteriaceae have recently emerged as a public threat in the treatment of nosocomial as well as community-acquired infections. Very little information is currently available about its existence in Nepal. We, therefore, aim to determine the prevalence of ESBL and AmpC-β-lactamase (ESBL)- and AmpC-Enterobacteriaceae have recently emerged as a public threat in the treatment of nosocomial as well as community-acquired infections. Very little information is currently available about its existence in Nepal. We, therefore, aim to determine the prevalence of ESBL and AmpC-

Methods

During a 6-month period (November 2014–April 2015), a total of 190 stool specimens from 190 participants were obtained from different population. Of the total 260 fecal isolates, 152 from outpatient department (OPD) and 108 from healthy volunteer were collected. Stool specimens were cultured and enterobacterial isolates were subjected to antimicrobial susceptibility tests according to the standard microbiologic guidelines. ESBL was screened using ceftazidime (CAZ, 30 μg) and cefotaxime (CTX, 30 μg) and cefotaxime (CTX, 30 β-lactamase (ESBL)- and AmpC-

Results

The prevalence of ESBL, AmpC-β-lactamase (ESBL)- and AmpC-β-lactamase (ESBL)- and AmpC-Enterobacteriaceae have recently emerged as a public threat in the treatment of nosocomial as well as community-acquired infections. Very little information is currently available about its existence in Nepal. We, therefore, aim to determine the prevalence of ESBL and AmpC-E. coli was 70.2% followed by K. pneumoniae (12.7%), and among AmpC-β-lactamase (ESBL)- and AmpC-E. coli was 70.2% followed by E. coli was 70.2% followed by K. pneumoniae (12.7%), and among AmpC-K. pneumoniae (12.7%), and among AmpC-C. freundii 2/7 (28.57%) were detected highest among AmpC-β-lactamase (ESBL)- and AmpC-

Conclusion

Our study revealed a high prevalence of ESBL- and AmpC-β-lactamase-producing enteric pathogen in Nepalese OPD and healthy population. The significant increase of these isolates and increased rate of drug resistance indicates a serious threat that stress the need to implement the surveillance system and a proper control measure so as to limit the spread of ESBL-producing Enterobacteriaceae (ESBL-PE) in both OPD as well as in community. Therefore, healthcare providers need to be aware that ESBL- and AmpC-β-lactamase-producing strains are not only circulating in hospital environments but also in the community and should be dealt with accordingly.β-lactamase (ESBL)- and AmpC-Enterobacteriaceae have recently emerged as a public threat in the treatment of nosocomial as well as community-acquired infections. Very little information is currently available about its existence in Nepal. We, therefore, aim to determine the prevalence of ESBL and AmpC-β-lactamase (ESBL)- and AmpC-

Antimicrobial resistance from a one health perspective in Cameroon: a systematic review and meta-analysis

Background

Antimicrobial resistance (AMR) is widely acknowledged as a global health problem, yet in many parts of the world its magnitude is not well elucidated. A baseline assessment of the AMR prevalence is a priority for implementation of laboratory-based AMR surveillance This review, focused on a One health approach, aimed at describing the current status of AMR in Cameroon.

Methods

PubMed, Google Scholar and African Journals Online databases were searched for articles published in English and French in accordance with the PRISMA guidelines. Retrieval and screening of article was done using a structured search string with strict inclusion/exclusion criteria. Free-text and grey literature were obtained by contacting the authors directly. The pooled prevalence and 95% confidence intervals were calculated for each pathogen–antibiotic pairs using random-effects models.

Result

Amongst 97 full-text articles reviewed, 66 met the eligibility criteria. The studies originated from the Centre (24; 36.4%), South-West (16; 24.2%), West (13; 19.7%), Littoral (9; 13.6%) and other (4; 6.1%) regions of Cameroon. These studies reported AMR in human (45; 68.2%), animals (9; 13.6%) and the environment (12; 18.2%). Overall, 19 species of bacteria were tested against 48 antibiotics. These organisms were resistant to all classes of antibiotics and showed high levels of multidrug resistance. Escherichia coli, Klebsiella pneumoniae and Staphylococcus spp were reported in 23, 19 and 18 of the human studies and revealed multidrug resistance (MDR) rates of 47.1% [95% CI (37.3–57.2%)], 51.0% [95% CI (42.0–59.9)] and 45.2% [95% CI (38.0–54.7)], respectively. Salmonella spp was reported in 6 of the animal studies and showed a MDR rate of 46.2% [95% CI (39.2–53.5%)] while Staphylococcus spp in 8 of environment studies showed MDR rate of 67.1% [95% CI (55.2–77.2%)].

Conclusion

This review shows that resistance to commonly prescribed antibiotics in Cameroon is high. The findings emphasize the urgent need to address gaps in the standardization of AMR diagnostics, reporting and use of available information to optimize treatment guidelines for the arsenal of antibiotics. Effective AMR surveillance through continued data sharing, large-scale collaboration, and coordination of all stakeholders is essential to understand and manage the AMR national burden.

High prevalence of extended-spectrum ß-lactamase producing enterobacteriaceae among clinical isolates in Burkina Faso

Background

Nothing is known about the epidemiology and resistance mechanisms of extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-PE) in Burkina Faso. The objective of this study was to determine ESBL-PE prevalence and to characterize ESBL genes in Burkina Faso.

Methods

During 2 months (June-July 2014), 1602 clinical samples were sent for bacteriologic investigations to the microbiology laboratories of the tree main hospitals of Burkina Faso. Isolates were identified by mass spectrometry using a matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) BioTyper. Antibiotic susceptibility was tested using the disk diffusion method on Müller-Hinton agar. The different ESBL genes in potential ESBL-producing isolates were detected by PCR and double stranded DNA sequencing. Escherichia coli phylogenetic groups were determined using a PCR-based method.

Results

ESBL-PE frequency was 58 % (179 strains among the 308 Enterobacteriaceae isolates identified in the collected samples; 45 % in outpatients and 70 % in hospitalized patients). The CTX-M-1 group was dominant (94 %, CTX-M-15 enzyme), followed by the CTX-M-9 group (4 %). ESBL producers were more often found in E. coli (67.5 %) and Klebsiella pneumoniae (26 %) isolates. E. coli isolates (n = 202; 60 % of all Enterobacteriaceae samples) were distributed in eight phylogenetic groups (A = 49, B1 = 15, B2 = 43, C = 22, Clade I = 7, D = 37, F = 13 and 16 unknown); 22 strains belonged to the sequence type ST131. No association between a specific strain and ESBL production was detected.

Conclusions

This report shows the alarming spread of ESBL genes in Burkina Faso. Public health efforts should focus on education (population and healthcare professionals), surveillance and promotion of correct and restricted antibiotic use to limit their dissemination.

[Evolution of antibiotic resistance of Enterobacteriaceae isolated at the Douala General Hospital from 2005 to 2012]

Introduction

Cette étude vise à déterminer le profil de résistance aux antibiotiques des entérobactéries isolées à l'Hôpital Général de Douala (Cameroun) et analyser leur évolution dans le temps.

Méthodes

Etude rétrospective, sur une période de huit ans (2005 - 2012), portant sur l'ensemble des souches d'entérobactéries isolées chez les malades ambulatoires et hospitalisés. Les prélèvements ont été analysés au laboratoire de bactériologie de l'Hôpital Général de Douala.

Résultats

Les entérobactéries étaient les germes les plus fréquents sur l'ensemble des souches isolées. Nous avons noté une prédominance d’Escherichia coli (48,5%) et de Klebsiella pneumoniae (32,8%). Pendant la période d’étude, nous avons observé des taux de résistance élevés aux principales classes d'antibiotiques, et une augmentation entre 2005 et 2012 de 29,1% à 51,6% pour les céphalosporines de troisième génération, de 29,2% à 44% pour la ciprofloxacine. L'imipénème, l'amikacine et la fosfomycine étaient les molécules les plus actives avec respectivement 1,3%, 12,9% et 13,4% des souches d'entérobactéries résistantes.

Conclusion

L’évolution des résistances des entérobactéries aux antibiotiques est un phénomène réel dans la ville de Douala. Il expose à des difficultés de prise en charge thérapeutique des infections. Lamaitrise actuelle de ce phénomène est une véritable urgence et nécessite une implication des pouvoirs publics. Des tests spécifiques de recherche des bétalactamases à spectre élargi (BLSE) et AmpC doivent être mis en place dans nos laboratoires afin de mettre en évidence les différents phénotypes de résistances.

High prevalence of antimicrobial resistance among common bacterial isolates in a tertiary healthcare facility in Rwanda

Antimicrobial resistance (AMR) is a serious public health threat in both developed and developing countries. Many developing countries, including Rwanda, lack adequate surveillance systems, and therefore, the prevalence of AMR is not well-known. We conducted a prospective observational study to assess the prevalence of AMR among common bacterial isolates from clinical specimens obtained from patients on the medical wards of Kigali University Teaching Hospital (KUTH). We evaluated the antibiotic sensitivity patterns of bacterial pathogens cultured from urine, blood, sputum, and wound swab specimens obtained over a 6-month period (July 1 to December 30, 2013). There were 154 positive cultures from specimens obtained from 141 unique patients over the study period. Urine, blood, wound swab, and sputum cultures comprised 55.2%, 25.3%, 16.2%, and 3.3% of the total specimens evaluated; 31.4% and 58.7% of Escherichia coli and Klebsiella isolates, respectively, were resistant to at least one of the third generation cephalosporins. Eight percent of E. coli isolates were resistant to imipenem; 82% and 6% of Staphylococcus aureus strains were oxacillin- and vancomycin-resistant respectively. Antimicrobial resistance rates are high in Rwanda and pose a serious therapeutic challenge to the management of common infections.

Asymptomatic bacteriuria in diabetes mellitus patients in Southwest Cameroon

BACKGROUND

Asymptomatic bacteriuria (ASB) is common in diabetics and predisposes these patients to more severe urinary tract infections (UTIs). Reports on the prevalence and etiology of ASB especially in developing countries appear contradictory.

OBJECTIVES

To determine the prevalence and etiology of ASB and antimicrobial resistance of urinary isolates in diabetics and non-diabetics.

METHODS

The study involved a total of 265 participants including 154 diabetes mellitus patients and 111 non-diabetics in Southwest Cameroon. Mid-stream urine was collected from consented subjects and each sample tested using the dipstick, microscopy and culture techniques. Isolates were identified using standard biochemical tests.

RESULTS

ASB was detected in 33.2% of participants; 38.3% in diabetics and 26.1% in non-diabetics (P = 0.03). Coagulase-negative staphylococci (CNS) were the predominant organisms (36.3%) isolated from urine in both diabetics and nondiabetics. Other isolates included Klebsiella sp (15.9%), Candida sp (13.7%), E. coli (10.8%) and Serratia sp (10.8%). Candida sp was isolated more from diabetics than non-diabetics (P = 0.01). There was no significant difference in resistance between diabetics and non-diabetics (P > 0.05). Most isolates showed multiple resistance and ciprofloxacin was the most active ingredient against bacterial uropathogens.

CONCLUSION

The study revealed a high prevalence of ASB in diabetics than in non-diabetics. A change in the aetiologic spectrum was observed with Staphylococcus sp accounting for majority of ASB. Most isolates showed multiple resistance in both diabetics and non-diabetics; therefore the need to speed up sensitization against antibiotic abuse in Southwest Cameroon.

Extended-spectrum β-lactamase-producing Enterobacteriaceae in Cameroonian hospitals

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae have been described worldwide, but there are few reports on the carriage of these bacteria in Cameroon. In order to investigate the types of ESBLs and to analyse some risk factors associated with ESBL carriage, faecal samples were collected between 3 January and 3 April 2009 from hospitalised patients at Yaounde Central Hospital and at two hospitals in Ngaoundere, Cameroon. Enterobacterial isolates resistant to third-generation cephalosporins were screened for ESBL production using the double-disk synergy test. Polymerase chain reaction (PCR) and DNA sequencing were performed in order to find out the different types of ESBL genes in presumptive ESBL-positive isolates. During the study period, a total of 121 different patients were screened for ESBL carriage. The prevalence among these patients whose faecal samples were found to contain ESBL-producers was 55.3 % (67/121). According to a univariate analysis, hospitalisation during the previous year was found to be associated with ESBL carriage. Of the 71 bacteria isolated, Escherichia coli was predominant and represented 48 % of all isolates. ESBL characterisation revealed two types of ESBLs, CTX-M-15 (96 %) and SHV-12 (4 %). The present study emphasises the importance of screening for ESBLs in laboratories in African countries. The monitoring and detection of ESBL-producing bacteria are important in the setting up of appropriate treatment of patients and to ensure effective infection control efforts.

Regional dissemination of a trimethoprim-resistance gene cassette via a successful transposable element

Background

Antimicrobial resistance is a growing international problem. We observed a 50% increase in the prevalence of trimethoprim resistance among fecal Escherichia coli from healthy Nigerian students between 1998 and 2005, a trend to increase that continued in 2009.

Methods and Findings

A PCR-based screen revealed that 131 (43.1%) of isolates obtained in Nigeria in 2005 and 2009 carried integron-borne dfrA cassettes. In the case of 67 (51.1%) of these isolates, the cassette was a class 1-integron-borne dfrA7 gene, which has been reported at high prevalence from E. coli isolates from other parts of Africa. Complete sequencing of a 27 Kb dfrA7-bearing plasmid from one isolate located the dfrA7 gene within a Tn21-type transposon. The transposon also contained an IS26-derived bla/sul/str element, encoding resistance to β-lactams, sulphonamides and streptomycin, and mercury resistance genes. Although the plasmid backbone was only found in 12 (5.8%) of trimethoprim-resistant isolates, dfrA7 and other transposon-borne genes were detected in 14 (16.3%) and 32 (26.3%) of trimethoprim resistant isolates collected in Nigeria in 2005 and 2009, respectively. Additionally, 37 (19.3%) of trimethoprim-resistant E. coli isolates collected between 2006 and 2008 from Ghana were positive for the dfrA7 and a transposon marker, but only 4 (2.1%) harbored the plasmid backbone.

Conclusions

Our data point to transposition as a principal mechanism for disseminating dfrA7 among E. coli from Nigeria and Ghana. On-going intensive use of the affordable broad-spectrum antibacterials is likely to promote selective success of a highly prevalent transposable element in West Africa.

Proportion of extended-spectrum ß-lactamase-producing Enterobacteriaceae in community setting in Ngaoundere, Cameroon

BACKGROUND

There is no information regarding the resistance mechanisms of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae in community setting in Cameroon. The current study aimed to determine the proportion of ESBLs in Enterobacteriaceae isolated in the community and to analyse some risk factors associated with ESBL carriage.

METHODS

Faecal samples were collected from 208 different outpatients and 150 healthy student volunteers between 3 January and 3 April 2009. Enterobacterial isolates resistant to third-generation cephalosporins were screened for ESBL production by the double-disk synergy test. Presumptive ESBL-producing isolates with positive synergy test were identified by Mass Spectrometry using the BioTyper MALDI-TOF. For such ESBL positive isolates, antibiotic susceptibility was determined by the Vitek 2 system. PCR and sequencing were performed for the detection of different types of ESBL genes in presumptive ESBL-producing isolates. Statistical methods were used for the univariate calculation of risk factors.

RESULTS

During the study period, a total of 358 faecal samples were analysed; 58 of such samples (16%) showed an ESBL phenotype and were confirmed by PCR. The proportion of ESBL producers in faecal carriage was statistically different between outpatients and student volunteers (23.1% vs. 6.7%: p < 0.000). According to a univariate analysis, previous use of antibiotics (ciprofloxacin) appeared to be a risk factor for ESBL carriage (p < 0.05).Escherichia coli was the species most frequently isolated among the ESBL producers in outpatients (66.7%) and student volunteers (90%). Isolates showed additional resistance to gentamicin, ciprofloxacin and trimethoprim/sulfamethoxazole but none of them was resistant to temocillin, amikacin or meropenem. Most of the strains (97%) produced a CTX-M group 1 enzymes [CTX-M-15 (98%) or CTX-M-1 (2%)] and the remaining strains produced SHV-12 enzyme (3%).

CONCLUSIONS

The use of drugs such as amoxicillin, ciprofloxacin and trimethoprim/sulfamethoxazole does not seem appropriate for empirical treatment because of emerging resistance. The implementation in Cameroon or in other African countries of methods of screening ESBL-producing organisms in routine laboratories is of great importance in order for us to offer patients appropriate treatment and for infection control efforts to succeed.