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Open Access Full Text Article  Research Article

Antibiotic Susceptibility Profile of Extended-Spectrum Beta-Lactamase in Escherichia Coli and Klebsiella Pneumonia from Urine Samples at Rwanda Military Hospital

NIYONZIMA William *, ISHIMWE Alain Prudence , UWIRINGIYIMANA Athanasie, MBABAZIZIMANA Fillette, MUKASHEMA Hyacinthe, BYIRINGIRO Verité, BUSHOBOZI Themistocles

INES-Ruhengeri, Institute of Applied Sciences, Faculty of Health Sciences, Department of Biomedical Laboratory Sciences, Musanze, Rwanda. 

 

 

Extended Spectrum Beta lactamases (ESBLs) are a group of plasmid-mediated β-lactamases rapidly evolving enzymes that are capable of hydrolyzing the third and fourth generation cephalosporins, monobactams, penicillin and sometimes carbapenems yet are inhibited by β-lactamase inhibitors. Extended Spectrum Beta lactamases (ESBLs) producing gram negative bacilli exhibit resistance against many classes of antibiotics, resulting in limitation of therapeutic options, posing a therapeutic challenge today in the treatment of hospitalized and community-based patients. Infections due to ESBL producing strains range from uncomplicated urinary tract infections to life-threatening sepsis¹ 

To survive the effects of antibiotics, some bacteria are constantly finding new defense strategies, called “resistance mechanisms. This resistance leads to a condition where fewer antibiotic options are available to treat bacterial infections, especially those caused by beta lactamase-producing strains. In many cases, even common infections, such as urinary tract infections, caused by ESBL-producing bacteria require more complex treatments. On the other hand, instead of taking antibiotics orally at home, patients with these UTIs may require hospitalization and intravenous (IV) carbapenem antibiotics²

Enterobacteriaceae, especially Klebsiella species producing ESBLs have been discovered since the 1980s as a major cause of hospital-acquired infections. However, during the late 1990s, several community-acquired microorganisms that commonly cause urinary tract infections and diarrhea have also been found to be ESBL producers and these include Escherichia coli, Salmonella, Shigella and Vibrio cholerae. ESBLs are often encoded by genes located on large plasmids, and these also carry genes for resistance to many antimicrobial agents such as aminoglycosides, tetracyclines, chloramphenicol and fluoroquinolone. Thus, very broad antibiotic resistance extending to multiple antibiotic classes is now a frequent characteristic of ESBL-producing bacteria³ 

β-Lactams are a group of antibiotics acting on the cell wall of a bacterial cell inhibiting the growth of sensitive bacteria by inactivating enzymes located in the bacterial cell membrane, which are involved in cell wall synthesis by binding to essential penicillin-binding proteins (PBPs). These include penicillins, cephalosporins, carbapenems, and monobactams. These bind to and inhibit the carboxypeptidases and transpeptidases. Resistance to β-lactams may be inherent to a particular species, which has inherently insensitive PBPs, may be acquired through spontaneous mutation or DNA transfer. Functionally, β-lactam resistance may be a result of the production of β-lactamases, impermeability, efflux and target modification⁴ 

The Clinical and Laboratory Standards Institute (CLSI) recommends a phenotypic combined-disk test for ESBL production in Enterobacteriaceae. It consists of measuring the growth-inhibitory zones around both cefotaxime (CTX) and ceftazidime (CAZ) disks with or without clavulanate (CA) for E. coli, K. pneumoniae, and Proteus mirabilis. The phenotypic confirmatory tests for ESBL production include cephalosporin/clavulanate combination discs method demonstrating a synergistic activity between a cephalosporin and a beta-lactamase inhibitor. There is difficulty in identifying ESBL-producing organisms in many clinical laboratories, making it likely that their prevalence is underestimated and knowledge among clinicians still low⁵ 

Extended spectrum beta-lactamase (ESBL) producing E. coli and K. pneumonia are becoming increasingly prevalent causative agents of urinary tract infections (UTIs). Antibiotic susceptibility testing of these bacteria reveals a high level of resistance to important beta-lactam antibiotics which are commonly used for the treatment of UTIs. As a result, the identification and treatment of ESBL-producing bacteria remain a significant challenge in clinical settings globally⁶. This study focus aimed to assess antibiotic susceptibility profile of extended spectrum beta lactamase producing E. coli and K. pneumonia isolated from urine samples of both inpatients and outpatients attending Rwanda Military Hospital (RMH). 

 

2. RESEARCH METHODOLOGY
   2. Study area

This study was conducted in the bacteriology service of Pathology laboratory department of the Rwanda Military Hospital (RMH) located in Kigali city.

This retrospective study was conducted among male and female patients who tested positive for ESBL-producing E. coli and K. pneumoniae and attended Rwanda Military Hospital for a urine antibiogram test. The study covered a four-month period from January to April 2024.

This study included 108 patients who met the inclusion criteria and attended Rwanda Military Hospital for urinalysis and antibiogram testing. All patients had positive test results for ESBL-producing E. coli and K. pneumonia. Only samples with complete information were included in this study.

The tested results of bacteria and antimicrobial resistance of patients were collected from the medical records (laboratory register). All data with complete documentation were selected and included in this study. Accordingly, the sample size of 108 patients was obtained.

Data were analyzed using Microsoft Excel 2016 and Statistical Package for the Social Science (SPSS) version 22.  Findings were presented in form of tables as frequency and/or percentages.

3. RESULTS AND DISCUSSION
   3. Patient’s demographic characteristics 

Table 1 represents demographic characteristics of patients diagnosed with Escherichia coli and Klebsiella pneumoniae at Rwanda Military Hospital regarding age and gender.

Table 1: Demographic characteristics of study participants

Variables			Frequency (n)	Percent (%)
Gender		Female	45	41.7%
		Male	63	58.3%
Total			108	100.0%
Age	[<25]		18	16.7%
	[26-50]		42	38.9%
	[51-75]		37	34.3%
	[>76]		11	10.2%
Total			108	100.0%

 

Majority of diagnosed patients were male with a frequency of 63(58.3%), and the female patients was 45 (41.7%) of the total 108 (100%) of targeted patients. Among the age group from diagnosed patients mostly affected age range were between [26-50] years with 42 patients corresponding to (38.9%), followed by [51-75] years with 37 patients equivalent to (34.3%), then [< 25] years with 18 patients contributing (16.7%), the least affected age crust were noted among [> 75] years with 11 patients corresponds to (10.2%) of total 108(100%) diagnosed patients requested for bacteriological exams.

The analysis of incidence by age group revealed a low rate in pediatric patients [<25] , with the highest incidence in adult patients aged between 51 and 75 years (34%) and [>76] (10%). These findings align with a study conducted by another researcher, who reported the highest infection rate in Italian individuals aged 65 years or older⁷. As noted in previous reports, patient gender is a risk factor in the distribution of ESBL producers⁸. In the present study, the prevalence of ESBL-producing E. coli and K. pneumoniae was found more in males than females (58% and 42%). The results are comparable to the studies done in Iran⁹.  

The table illustrates the distribution of Escherichia coli and Klebsiella pneumoniae across different gender and age groups. In analyzing the distribution of those bacterial pathogens, my study reveals that E. coli is significantly more prevalent than K. pneumoniae across both genders.

Escherichia coli accounts for 82.4% of cases, with a nearly equal distribution observed in both females (82.2%) and males (82.5%). This prevalence aligns with findings from recent studies highlighting E. coli as the predominant pathogen in various infections¹⁰. In contrast, K. pneumoniae constitutes a smaller portion of infections at 17.6%, with a slightly lower distribution in females (17.8%) compared to males (17.5%). This trend is consistent with current literature suggesting that K. pneumoniae, while significant, is less frequently encountered than E. coli in similar settings¹⁰. The marked predominance of E. coli over K. pneumoniae across genders underscores its role as a major pathogen in the population studied.

Table 2: Distribution of E. coli and K. pneumonia causing urinary tract infections according to age and gender 

Variables	Escherichia coli	Klebsiella pneumoniae	Total
Gender
Female	37(82.2)	8(17.8)	45(100)
Male	52(82.5)	11(17.5)	63(100)
Total	89(82.4)	19(17.6)	108(100)
Age
[<25]	17(94.4)	1(5.6)	18(100)
[26-50]	32(76.2)	10(23.8)	42(100)
[51-75]	31(83.8)	6(16.2)	37(100)
[>76]	9(81.8)	2(18.2)	11(100)
Total	89(82.4)	19(17.6)	108(100)

 

Age-specific analysis reveals that E. coli is most common in individuals under 25 years (94.4%), it is found that E. coli infections are particularly prevalent among younger individuals, similar to my observation that the [<25] age group has the highest prevalence of E. coli and highlights the higher susceptibility of younger populations to E. coli infections, potentially due to different risk factors and exposure rates¹¹. While K. pneumoniae is least frequent in this age group and peaks in the [26-50] years (23.8%) and these findings align with recent study which reported that K. pneumoniae infections are more common in middle-aged adults, and suggested that the increased prevalence in this age group could be attributed to chronic health conditions and changes in immune function¹².

This study showed very high levels of resistance to antibiotics among ESBL-producing gram-negative bacteria causing complicated UTIs. Carbapenems (meropenem) and piperacillin-tazobactam were the relatively effective agents against ESBL-positive E. coli and K. pneumoniae strains. This study is in the same line with the study conducted in Iran evaluation of antibiotic susceptibility pattern of extended spectrum beta lactamases producing bacteria.   Furthermore, these bacteria are resistant not only to extended-spectrum cephalosporins including ceftazidime, ceftriaxone, cefepime, but also penicillins¹³.

 

 

DIAGNOSIS	Antibiotic	n	Susceptibility, n(%)
			Resistant	Sensitive
Escherichia coli	Cefotaxime	59	54(91.5)	5(8.5)
	Ceftazidime	69	65(94.2)	4(5.8)
	Ceftriaxone	52	43(82.7)	9(17.3)
	Meropenem	62	18(29)	44(71)
	Piperacillin tazobactam	71	25(35.2)	46(64.8)
	Cefepime	19	13(68.4)	6(31.6)
	Amoxicillin + clavulanic acid	63	47(74.6)	16(25.4)

 

Among the E. coli positive patients, there were 89 (82.4%) cases. The bacteria showed high resistance to the antibiotics ceftazidime (CAZ) and cefotaxime (CTX), with resistance rates of 65 (94%) and 54 (92%) patients, respectively, moderate resistance was observed on Amoxicillin+clavulanic acid (AMC) and Cefepime (CFM) resisted on 47(75%) and 13(68.4%) patients.  The first sensitive antibiotic was Meropenem (MEM), which was effective in 44 (71%) patients, followed by Piperacillin/tazobactam (TZP), which was effective in 46 (65%) patients.

E. coli showed moderate sensitivity to two antibiotics among the antibiotics that were routinely used with notable percentages, Meropenem, and Piperacillin-tazobactam, with sensitivities of 71 % and 65% respectively. These results were similar to those obtained in the current study where Meropenem and piperacillin-tazobactam, produced bacteriologic improvement in <15% resistance. These results underscore their potential as effective treatment options for E. coli infections¹⁴.

In contrast, CAZ and CTX face considerable challenges, with resistance rates of 83% and 92% respectively, underscoring the limited utility of these antibiotics in treating E. coli infections. This might be due to the extensive use and misuse of those drugs in the population. These results accentuate the urgent need for cautious antibiotic prescribing practices and the exploration of alternative treatment strategies to combat rising antibiotic resistance in E. coli. This study is similar to the study where the antimicrobial sensitivity analysis revealed low sensitivities towards ceftazidime, and cefotaxime (85.4 and 100%) respectively, suggesting that these drugs are no longer effective for ESBLs empirical¹⁵.

 

 

DIAGNOSIS	Antibiotic	n	Susceptibility, n(%)
			Resistant	Sensitive
Klebsiella pneumoniae	Cefotaxime	14	13(92.9)	1(7.1)
	Ceftazidime	9	7(77.8)	2(22.2)
	Ceftriaxone	12	11(91.7)	1(8.3)
	Meropenem	10	5(50)	5(50)
	Piperacillin tazobactam	13	5(38.5)	8(61.5)
	Cefepime	7	6(85.7)	1(14.3)
	Amoxicillin + clavulanic acid	17	14(82.4)	3(17.6)

 

 

Among resistance on K. pneumoniae higher resistance was observed on the following antibiotics cefotaxime (CTX), ceftriaxone (CTR), and Amoxicillin+clavulanic acid (AMC) with 93%, 92%, and 83%, patients successively, moderate resistance was noted on ceftazidime (CAZ) and Cefepime (CFM) with 78% and 86% patients respectively. For sensitivity action, the mostly sensitive antibiotics were Piperacillin tazobactam (TZP) which was sensitive to 62% patients, and Meropenem (MEM) was next with 50% patients, of a total of 17.59% patients who were K. pneumoniae positive.

Klebsiella pneumonia also showed a high resistance pattern towards third and fourth-generation cephalosporins such as ceftriaxone, cefotaxime, cefepime, and Amoxicillin+clavulanic acid with corresponding percentages 92%, 93%, 86% and 83% which is similar to the one done by Siriphap, where the resistance rate of K. pneumonia and 71.3% for cefotaxime and ceftazidime, (100%) and ceftazidime (85.4%)⁶. Conversely, piperacillin-tazobactam exhibited moderate susceptibility at 62% and 50%, which is lower compared to the susceptibilities of 80% and 78%¹⁶.

Figure 1 below presents a comparison of the antibiotic resistance and sensitivity profiles of Escherichia coli and Klebsiella pneumoniae based on the provided data, notable differences in resistance and sensitivity emerge, highlighting that E. coli generally exhibits higher resistance and sensitivity rates compared to K. pneumoniae, indicating a more challenging scenario for treatment with certain antibiotics

 

.

Figure 1: Antibiogram of both E. coli and K. pneumonia

 

 

The chart above demonstrates antibiotic susceptibility patterns of E. coli and K. pneumonia, the most resistance pattern was observed on E. coli with 69 patients on CAZ antibiotics followed by CTX with 54 patients, while the highest sensitivity pattern was noted in E. coli again with 44 patients on MEM and 46 on TZP, simply E. coli were having extended patterns of both resistance and sensitive than K. pneumonia. 

Specifically, E. coli exhibits the highest resistance to ceftazidime, with 94.2% of isolates being resistant. This is in stark contrast to K. pneumoniae, where 77.8% of isolates are resistant to ceftazidime. A closer look at the data reveals that the highest resistance rate for E. coli is observed with ceftazidime (94.2%), and for K. pneumoniae, the highest resistance is to cefotaxime (92.9%). This significant difference in resistance patterns indicates that E. coli is more resistant to ceftazidime than K. pneumoniae is to cefotaxime. This finding aligns with recent studies that highlight increasing resistance trends in E. coli, particularly to cephalosporins like ceftazidime, which are crucial for treating various infections¹¹.

Moreover, E. coli also shows higher resistance to cefepime (68.4%) compared to K. pneumoniae (85.7%). While both pathogens exhibit significant resistance to cefepime, E. coli’s resistance rate is notably lower. This indicates that K. pneumoniae might pose a greater challenge in cases where cefepime is used as a treatment option. Research supports this observation, noting that cefepime resistance in K. pneumoniae has been increasing due to the spread of ESBLs¹⁷.

On the sensitivity front, E. coli demonstrates higher sensitivity to Meropenem compared to K. pneumoniae. In E. coli, 71% of isolates are sensitive to Meropenem, while only 50% of K. pneumoniae isolates show sensitivity to this antibiotic. This suggests that Meropenem may be a more reliable treatment option for E. coli infections than for K. pneumoniae. Recent studies corroborate this, showing that meropenem remains one of the most effective treatments for resistant strains of E. coli¹⁸.

Additionally, E. coli exhibits higher sensitivity to piperacillin-tazobactam (64.8%) compared to K. pneumoniae (61.5%). Although the difference is not as pronounced, it still indicates a trend where E. coli may respond better to piperacillin-tazobactam than K. pneumoniae. This finding is supported by contemporary research, which shows that piperacillin-tazobactam retains significant efficacy against E. coli, though resistance is emerging¹⁹.

In conclusion, the findings underscore the significant prevalence of Extended Spectrum Beta Lactamase-producing organisms, primarily E. coli and K. pneumoniae, among which male patients are disproportionately affected. The high resistance rates observed against key antibiotics, including Amoxicillin/clavulanic acid, Cefotaxime, Ceftriaxone, and cefepime, highlight the urgent need for tailored antimicrobial strategies to combat these pathogens effectively. 

Acknowledgements: Our gratitude is extended to the Rwanda Military Hospital administration for facilitating this study at their health facilities. 

Conflict of interest: Authors declare no conflict of interest 

Availability of raw data and material: Raw data and information on material should be obtained from the corresponding author upon request. 

Author Contributions: All authors have equal contributions in the preparation of the manuscript and compilation. 

Source of Support: Nil 

Funding: The authors declared that this study has received no financial support. 

Ethical approval: Official approval to conduct this research was obtained from INES Ruhengeri and submitted to the ethical committee of Rwanda Military Hospital with a letter requesting data collection. Approval letter for data collection was obtained from Rwanda Military Hospital before data collection.  All research methods were performed in accordance with the relevant guidelines and regulations. The data obtained was kept confidential and used for academic purposes.

REFERENCES

1. Falcone M., Vena A., Mezzatesta M. L., Gona F., Caio C., Goldoni P., et al. Role of empirical and targeted therapy in hospitalized patients with bloodstream infections caused by ESBL-producing Enterobacteriaceae. Ann Ig, 2014; 26, 293-304.

2. Nguyen, M., et al. "Emerging Treatment Options for Infections Caused by ESBL-producing Enterobacteriaceae," Antimicrobial Agents and Chemotherapy, 2022; 67(9), 2302-22.

3. Stone, G. G. "Understanding the Epidemiology of ESBL-producing Escherichia coli and Klebsiella pneumoniae in Community and Healthcare Settings," Journal of Infection Control and Hospital Epidemiology,2023; 44(2), 112-123.

4. Mora-Ochomogo, M. & Lohans, T. β-Lactam antibiotic targets and resistance mechanisms: from covalent inhibitors to substrates. RSC Medicinal Chemistry,2021; 12(10), 1623-1639. https://doi.org/10.1039/D1MD00200G PMid:34778765 PMCid:PMC8528271

5. Sahni, R. D., Mathai, D., Sudarsanam, T. D., Balaji, V., Brahamadathan, K. N., Jesudasan, M. V., & Lalitha, M. K. Extended-Spectrum Beta-lactamase Producers: Detection for the Diagnostic Laboratory. Journal of Global Infectious Diseases, 2018;10(3), 140-146. https://doi.org/10.4103/jgid.jgid_49_17 PMid:30166813 PMCid:PMC6100337

6. Siriphap, A., Kitti, T., Khuekankaew, A., Boonlao, C., Thephinlap, C., Thepmalee, C., Suwannasom, N., & Khoothiam, K. High prevalence of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates: A 5-year retrospective study at a Tertiary Hospital in Northern Thailand. Frontiers in Cellular and Infection Microbiology, 2022;12(1), 955774. https://doi.org/10.3389/fcimb.2022.955774 PMid:36004324 PMCid:PMC9393477

7. Cassini, A., Högberg, L. D., Plachouras, D., Quattrocchi, A., Hoxha, A., Simonsen, G. S., Colomb-Cotinat, M., Kretzschmar, M. E., Devleesschauwer, B., Cecchini, M., Ouakrim, D. A., Oliveira, T. C., Struelens, M. J., Suetens, C., Monnet, D. L., & Burden of AMR Collaborative Group. Attributable deaths and disability-adjusted life-years caused by infections with antibiotic-resistant bacteria in the EU and the European Economic Area in 2015: a population-level modeling analysis. The Lancet. Infectious Diseases, 2019;19(1), 56-66. https://doi.org/10.1016/S1473-3099(19)30004-0 PMid:30722997

8. Xiao, T., Wu, Z., Shi, Q., Zhang, X., Zhou, Y., Yu, X., & Xiao, Y. A retrospective analysis of risk factors and outcomes in patients with extended-spectrum beta-lactamase-producing Escherichia coli bloodstream infections. Journal of global antimicrobial resistance, 2019;17(1), 147-156.https://doi.org/10.1016/j.jgar.2018.12.014 PMid:30634054

9. Peerayeh, S. N., Rostami, E., Eslami, M., & Rezaee, M. A. High frequency of extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Escherichia coli isolates from male patients' Urine. Archives of Clinical Infectious Diseases, 2016;11(2).

10. Patel, M., Davidson, M., & Smith, J. Gender Differences in Bacterial Infections: A Comprehensive Review. Infectious Disease Reports,2023; 15(2), 112-123.

11. Smith, D., Jones, L., & Wu, T.The Rise of Cephalosporin Resistance in E. coli: A Review. European Journal of Clinical Microbiology & Infectious Diseases, 2023;42(3), 567-575.

12. Johnson, T., Lee, H., & Patel, R. Epidemiological Trends in Klebsiella pneumoniae Infections: A Review. Journal of Clinical Microbiology, 2023; 61(4), e00345-23.

13. Ibrahim, H. I., Al Rasheed, A. A., & Noomi, B. S. A study on the pathogenicity of escherichia coli producing extended-spectrum β isolated from urological patients and its association with some immunological biomarkers from hospitalized adult patients. In Obstetrics and Gynaecology Forum,2024; 34(3), 1772-1780.

14. Keshi, L., Weiwei, X., Shoulin, L., Xiadong, L., Hao, W., Junhai, J., Xiangwei, W., Rui, W., & Pei, Z. Analysis of drug resistance of extended-spectrum beta-lactamases-producing Escherichia coli and Klebsiella pneumonia in children with urinary tract infection. Saudi Medical Journal,2019; 40(11), 1111-1115. https://doi.org/10.15537/smj.2019.11.24547 PMid:31707407 PMCid:PMC6901762

15. Kumar, D., Singh, A. K., Ali, M. R., & Chander, Y. Antimicrobial susceptibility profile of extended spectrum β-lactamase (ESBL) producing Escherichia coli from various clinical samples. Infectious Diseases: Research and Treatment, 2014; 7, IDRT-S13820. https://doi.org/10.4137/IDRT.S13820 PMid:24847178 PMCid:PMC4024053

16. Ezure, Y., Rico, V., Paterson, D. L., Hall, L., Harris, P. N., Soriano, A., & Wright, H. Efficacy and safety of carbapenems vs new antibiotics for treatment of adult patients with complicated urinary tract infections: a systematic review and meta-analysis. US: Oxford University Press, In Open Forum Infectious Diseases,2022; 9(5). https://doi.org/10.1093/ofid/ofaa480 PMid:35474756 PMCid:PMC9031024

17. Johnson, R., & Clarke, H. Increasing Resistance to Cefepime in Klebsiella pneumoniae. Antimicrobial Agents and Chemotherapy,2023; 67(4), 789-795.

18. Brown, A., Smith, J., & Clark, M. Efficacy of Meropenem against Multi-Drug-Resistant E. coli. Journal of Clinical Microbiology, 2024; 62(2), 122-130.

19. Lee, S., Chen, Y., & Patel, K. Trends in Resistance to Piperacillin-Tazobactam in E. coli and K. pneumoniae. Infection Control & Hospital Epidemiology,2024; 45(1), 112-119.