Extended spectrum beta lactamase producing bacteria among outpatients with ear infection at FelegeHiwot Referral Hospital, North West Ethiopia

Antibiogram and molecular characterization of extended-spectrum β-lactamase-producing pathogens implicated in chronic suppurative otitis media

Introduction

beta-lactamase-producing bacteria, especially extended-spectrum beta-lactamase (ESBL) producers have strong clinical relevance and have been implicated in chronic suppurative otitis media (CSOM) treatment failures. This study aimed to determine the frequency, antibiogram, and molecular characteristics of ESBL-producing gram-negative bacterial (GNB) pathogens isolated from patients with CSOM.

Methods

three hundred (300) ear swab samples collected from patients with active CSOM were analysed using standard microbiological techniques. Antibiogram of pathogens was determined by Kirby-Bauer disk diffusion technique. Phenotypic detection and molecular characterization of ESBL-producing GNB pathogens were performed by double disk synergy test (DDST) and polymerase chain reaction (PCR).

Results

Escherichia coli and P. aeruginosa were more prevalent among CSOM patients with a duration of discharge >2 weeks. The frequency of ESBL producers among the GNB pathogens was 18.3%. Isolates were generally multidrug-resistant but very susceptible (100% - 70.4%) to ciprofloxacin, imipenem, and amikacin. Multiple antibiotic resistance values of the isolates ranged from 0.7-0.8. Polymerase chain reaction showed that blaSHV (47.6%) was the most predominant ESBL genotype. This was followed by blaTEM (25.2%) and blaCTX-M (10.7%) as the least predominant ESBL gene. Concomitant expression of ESBL gene was observed in 13.6% of the isolates.

Conclusion

this study reported the occurrence and spread of β-lactamase-producing bacteria in patients with CSOM infections. It is therefore very crucial to screen for antibiotic-resistant pathogens at early stages of CSOM infections, for proper antimicrobial therapy and to curb the increasing spread of antimicrobial resistance.

Detection of FOX-AmpC-β-lactamase gene and antibiogram of AmpC-beta-lactamase-producing pathogens isolated from chronic suppurative otitis media patients in Nigeria

Background and Objectives

AmpC-producing Gram-negative bacterial (GNB) pathogens are distributed worldwide, especially in clinical settings. This study aimed to determine the antibiogram and the type of AmpC-β-lactamase gene harboured by GNB pathogens implicated in chronic suppurative otitis media (CSOM) cases.

Materials and Methods

Ear swab samples (300) collected from patients with active CSOM were analysed using standard microbiological techniques. Phenotypic and molecular detection of AmpC β-lactamase production was done by cefoxitin/cloxacillin double-disk synergy test and PCR respectively. Antibiogram was determined by disk diffusion technique.

Results

Among the GNB pathogens isolated from CSOM patients, P. aeruginosa was the most predominant (36.3%); followed by K. pneumoniae (22.3%), and E. coli (13.7%). Patients with active CSOM showed increased bacteria isolation rate from bilateral ear discharges than unilateral ear discharges. E. coli and P. aeruginosa were more prevalent among patients with duration of discharge >2 weeks; recording 9.0% and 20.3% respectively. AmpC β-lactamase producers accounted for 14.0%; they were highly resistant (60%-100%) to cephalosporins, trimethoprim-sulfamethoxazole, ofloxacin, amoxicillin, and tetracycline, but very susceptible (70.4%-100%) to ciprofloxacin, imipenem, and amikacin. Multiple antibiotic resistance indices of isolates ranged from 0.7-0.8. FOX-AmpC-β-lactamase gene was detected in 3.9% of the isolates.

Conclusion

The detection of AmpC β-lactamase-producing multidrug-resistant GNB pathogens harbouring FOX-AmpC-β-lactamase gene among patients with CSOM infections in our study is a serious public health problem which needs urgent intervention.

Aetiology of ear infection and antimicrobial susceptibility pattern among patients attending otorhinolaryngology clinic at a tertiary hospital in Dar es Salaam, Tanzania: a hospital-based cross-sectional study

OBJECTIVES

To determine the aetiological pathogens causing ear infections and their antimicrobial susceptibility patterns among patients with ear complaints at a tertiary hospital in Dar es Salaam.

DESIGN

Hospital-based cross-sectional study.

SETTINGS

Otorhinolaryngology clinic at Muhimbili National Hospital, Dar es Salaam, Tanzania.

PARTICIPANTS

Patients presenting with signs and symptoms of ear infection.

MAIN OUTCOME MEASURE

Bacteria and fungi isolated from ear swab specimens of patients presenting with signs and symptoms of ear infection; and antimicrobial susceptibility patterns of isolated bacteria.

RESULTS

Two hundred and fifty-five participants were enrolled, with a median age of 31 years and an IQR of 15-49. Otitis externa was the predominant type of ear infection, accounting for 45.1%. We observed positive bacteria culture in 53.3% of study participants, in which 41% of isolates were obtained from patients with chronic suppurative otitis media. Moreover, Staphylococcus aureus (27.3%) and Pseudomonas aeruginosa (24.2%) were the most frequently isolated bacteria, while Candida spp, 12 (63.8%) and Aspergillus spp, 9 (36.2%) were the only isolated fungi. Furthermore, we report that 93% of isolated Enterobacterales were resistant to amoxicillin/clavulanic acid, and 73% were resistant to ceftazidime. In addition, we detected 34.4% extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and 44.4% methicillin-resistance S. aureus (MRSA). We also found that 22% of the bacteria isolates were resistant to ciprofloxacin, a primary topical antibiotic used in managing ear infections.

CONCLUSIONS

The findings from this study reveal that the leading aetiological agent of ear infection is bacteria. Furthermore, our findings show a significant proportion of ESBL-PE and MRSA-causing ear infections. Hence, detecting multidrug-resistant bacteria is crucial to improving ear infection management.

Bacterial Etiologies of Ear Infection and Their Antimicrobial Susceptibility Pattern at the University of Gondar Comprehensive Specialized Hospital, Gondar, Northwest Ethiopia: A Six-Year Retrospective Study

BACKGROUND

An ear infection is responsible for up to 40% of preventable hearing impairment; one of the reasons for frequent and unwise antibiotic usage, especially in the developing world. Since the incidence of antibiotic resistance is increasing, especially in resource-limited countries, up-to-date knowledge on the susceptibility of ear-discharge isolates to antibiotic is important for better patient treatment. Therefore, this study aimed at determining the bacterial etiologies and their antibiotic susceptibility profiles among patients suspected with ear infections.

METHODS

We collected retrospective data from bacteriological results of ear discharge samples from 2013 to 2018. Sample collection, culture preparation, and bacterial identification were performed using standard microbiological techniques. Antimicrobial susceptibility testing was performed following Clinical and Laboratory Standard Institute (CLSI) guidelines. We extracted and inputted the data using Epi-info version 7 and exported it to SPSS version 20 for analysis.

RESULTS

The overall ear-discharge culture positivity rate was 283/369 (76.7%) (95% CI = 72.4-81.3), with 14/283 (4.95%) mixed infections. Staphylococcus aureus (27.9%), Proteus spps (20.8%), Streptococcus spps (10%), and Pseudomonas spps (8.92%) were the main isolates. High-level resistance rates for tetracycline (77.6%), penicillins (67.2%), erythromycin (52.6%), and co-trimoxazole (52%), and low-level resistance rates for fluoroquinolones (23.3%), aminoglycosides (23.7%), and cephalosporins (29.8%) were observed. More than 45% of isolates, with 50.9% of Gram-negative and 37.3% of Gram-positive, were multidrug-resistant.

CONCLUSION

Staphylococcus aureus, Proteus mirabilis, Proteus vulgaris, Escherichia coli, and Pseudomonas aeruginosa were the leading cause of ear infections. The presence of high number of multidrug-resistant strains calls for the need for periodic and continuous follow-up of antibiotic usage in the study area. Further studies are recommended to explore the types of ear infections, with their etiologic agents and possible risk factors.

Microbiology of Chronic Suppurative Otitis Media: An update from a Tertiary Care Hospital in Bangladesh

Objectives:

Chronic suppurative otitis media is a major cause of acquired hearing impairment, especially in children of developing countries. The study sought to explore the bacteriological profile and their antimicrobial susceptibility among patients of chronic suppurative otitis media from a tertiary care hospital in Bangladesh.

Methods:

A cross sectional microbiological study was conducted at the Department of Microbiology, Rajshahi Medical College, Bangladesh from January to December 2019. Aural swabs were collected aseptically from clinically suspected patients irrespective of age and gender attending the ear, nose and throat outpatient department of Rajshahi Medical College Hospital. Aerobic bacterial culture was done and isolates were identified through standard bacteriological identification scheme. Antimicrobial susceptibility testing of isolates was done by modified Kirby-Bauer disk diffusion method following Clinical and Laboratory Standards Institute guidelines.

Results:

Of 96 swabs, culture yielded a total of 73 bacterial isolates from 68(70.8%) culture-positive plates including 63 (65.6%) unimicrobial and 5 (5.2%) polymicrobial (mixed growth of a pair of bacteria) growths. Frequency distribution revealed, 40(55%) gram-negative and 33(45%) gram-positive bacteria with Staphylococcus aureus was the leading isolate (37%) followed by Pseudomonas aeruginosa (31.5%), Escherichia coli (13.7%), coagulase-negative Staphylococcus (8.2%), Klebsiella pneumoniae (5.5%) and Proteus spp. (4.1%). Gram-positive bacteria were found to be highly susceptible (100%) to Linezolid and Vancomycin followed by Imipenem (83 to 96.3%), while moderate to high resistance (44 to 67%) was observed against Ciprofloxacin, Ceftriaxone, Ceftazidime, Amoxicillin/Clavulanate and Clindamycin. For gram-negative bacteria, susceptibility ranged from 67 to 100% to Imipenem, 67 to 96% to Piperacillin/Tazobactam and 67 to 83% to Gentamicin, while moderate to high resistance (50 to 75%) was observed against Ciprofloxacin, Ceftriaxone, Ceftazidime and Amoxicillin/Clavulanate.

Conclusion:

Moderate to high level of multidrug-resistance especially to 3^rd generation cephalosporins, Ciprofloxacin and Amoxicillin/Clavulanate is an alarming situation. It warns reinforcement of judicious antibiotic prescription and introduction of antibiotic stewardship program in the tertiary care hospitals.