ISSN: 0973-7510
E-ISSN: 2581-690X
Cities across Saudi Arabia are grappling with expanding rates of antimicrobial resistance, fuelled in part by overuse of antibiotics. Nevertheless, surveillance of antimicrobial resistance has been scanty, especially in regions such as Makkah, which renders this study to be very significant in shaping up the regional and national public health policies. The study has been conducted at Al-Noor Specialist Hospital in Makkah from November 2024 to April 2025. Both sexes were included (30-70 years of age). A total 960 specimens were obtained from patients at Al-Noor Hospital in Makkah. The positive culture rates were as follows: Escherichia coli 310, Klebsiella 233, Pseudomonas aeruginosa 157, Acinetobacter 114, Enterobacter 80 and Proteus 66. Highest number of1152 isolates in bacteriological examination was 148 from bronchial aspiration samples. Subsequent gastrointestinal symptoms (132) and urine C/S tests done (122). The findings indicated that 69.6% of the isolates were multidrug-resistant (MDR), 18.2% were extensively drug resistant (XDR), and 11.7% were pandrug resistant (PDR). We observed high susceptibility to amikacin, gentamicin, and cefotaxime. These results indicate a pan-drug resistance situation, which calls for continuous monitoring, research and development to prevent further spread of resistance, and to safeguard the efficacy of present regimens. This study infers that the resistance rates of antibiotics in pathogens are higher in the Kingdom and some of the world studies.
Multidrug-resistant Bacteria, Extensively Drug-resistant Bacteria, Gram-negative, Antibiotic Resistant
The battle against Gram-negative bacteria (GNB) resistance, whether in the context of the term multidrug-resistant or not, has become one of the most significant worldwide health threat due to the limitation of therapeutic armamentarium against a broad spectrum of infections.1 Common microbial agents implicated in healthcare-associated infections include Escherichia coli, Klebsiella species, Pseudomonas species, and Acinetobacter species. A growing concern is the escalating resistance demonstrated by these organisms to multiple antimicrobial classes, including carbapenems, which are typically considered a therapeutic option of last resort.2 What makes Gram-negative bacteria particularly formidable is their inherent structural and biochemical defenses. Their outer membrane, composed of lipopolysaccharides, not only enhances virulence but also acts as a formidable barrier to many antibiotics.3 Moreover, these bacteria can enact various resistance mechanisms, including efflux pumps, porin alterations, as well as beta-lactamase production, among others, to escape even strong antimicrobial agents.4 The capacity of Gram-negative bacteria to acquire resistance genes via horizontal gene transfer is a significant concern, facilitating the swift propagation of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains.5 Consequently, healthcare professionals frequently encounter resistant Gram-negative bacterial infections in clinical settings, particularly in intensive care units (ICUs), surgical wards, and among immunocompromised individuals.6 These infections manifest as urinary tract infections (UTIs), ventilator-associated pneumonia (VAP), bloodstream infections (BSIs), and skin and soft tissue infections. Recognizing the severity of the threat, the World Health Organization (WHO) has designated certain Gram-negative bacteria as “critical priority” pathogens, emphasizing the urgent need for novel antimicrobial agents and improved strategies for infection control.7 In Saudi Arabia, the growing burden of MDR Gram-negative infections mirrors global trends but is intensified by unique local dynamics. Rapid healthcare expansion, high volumes of international travelers particularly during Hajj and Umrah and inconsistent antibiotic prescription practices have all contributed to a complex and evolving resistance landscape.8 Studies from Saudi hospitals have documented high resistance rates, especially in tertiary care centers and ICU settings. Regional disparities also exist, with central and western regions reporting notably higher levels of resistance.9 The prevalence of ESBL (extended-spectrum beta-lactamase) producing E. coli and K. pneumoniae, Carbapenem-resistant A. baumannii and P. aeruginosa has complicated the empirical therapy.10 Unfortunately, resistance to colistin, one of the last therapeutic options available, is increasingly being reported.11 These patterns are correlated with prolonged hospital stay, increased mortality, and enhanced costs of medical care. Although attempts have been made to enforce antimicrobial stewardship programs (ASPs) on a national level, compliance is notably lacking. The spread of resistance is still being driven by factors like overuse of broad-spectrum antibiotics, poor access to rapid diagnostic services, and poor infection prevention control practices.12 The present study was conducted to determine the prevalence and resistance rates of Gram-negative pathogens isolated at Al-Noor Hospital in Makkah, Kingdom of Saudi Arabia. This is at least in part highly relevant since resistance rates differ considerably between classes of antimicrobials.
Ethical Aspects
This study was conducted to evaluate the level of medical care and its impact on patient satisfaction with medical and nutritional health services in the Makkah region of Saudi Arabia. The study was approved by the Medical Research Ethics Committee in Makkah, Saudi Arabia. Written informed consent was obtained from each participant before completing the study questionnaire. The confidentiality of all research data was guaranteed, and participation was voluntary. The following were explained:
• The nature of the study and its protocols.
- The potential risks and benefits associated with the study.
- Voluntary participation.
- The freedom to withdraw from the study at any time.
- The reliability of the results.
Study setting, period, and population
Random samples were collected from 960 patients in the Microbiology Department at Al-Noor Specialist Hospital (ASH) in Makkah between November 2024 to April 2025. Strict sterile testing was performed on patients during clinical sample collection, including blood, urine, and wound samples. In the laboratory, susceptibility to antibiotics was evaluated based on the trends emerging from all the reports containing resistance data for the six Gram-negative bacterial isolates (Escherichia coli, Acinetobacter species, Klebsiella species, Pseudomonas species, Enterobacter species and Proteus species) responsible for the infections.
During the study period, all patients visiting Al-Noor Hospital in Makkah to avail healthcare services were requested to provide the relevant information. At least gender, age, and ward type were included in the study. Data with missing information on age, gender, and ward type were excluded.
Sample collection, isolation, and identification
The entire collection of samples was done in sterile containers at different times during the research period, and undoubtedly treated to eliminate the possibility of contamination and quick transportation to the lab. The examination was conducted according to the standard procedures and was done within six hours after the collection. The samples were inoculated with a sterile loop on different types of culture media like blood agar, cysteine lactose electrolyte agar, xylose lysine deoxycholate agar, and MacConkey agar. The aforementioned media were selected because they can isolate Gram-negative bacteria from clinical specimens effectively, specifically and reliably. They also support the growth of bacteria and at the same time, the pathogens can be identified easily, which is vital for the studies of drug resistance and treatment strategy development. Plates were incubated for 24 hours at 33 °C, except for chocolate agar plates (incubated for 24 hours at 37 °C without air). Automated methods using a BD-Phoenix 100 analyzer were used to identify the organisms correctly.
Antimicrobial susceptibility
The determination of antibiotic susceptibility was done by applying the Kirby-Bauer disk diffusion method. The broth microdilution technique was employed to ascertain the MICs of important antibiotics. The interpretation of resistance was based on the guidelines of the Clinical and Laboratory Standards Institute (CLSI). The GNB isolates were tested for susceptibility to the following antibiotics: ceftriaxone, ampicillin, cefuroxime, ciprofloxacin, levofloxacin, amikacin, gentamicin, colistin, erythromycin, and mupirocin.
Statistical analysis
The source data pertaining to the isolates was compiled, refined, and coded using Microsoft Excel 2016. Descriptive statistical analysis, incorporating means and percentages, was conducted to determine: the proportion of patients affected by multidrug-resistant Gram-negative bacteria; a comparative evaluation of resistance profiles across various demographic and clinical categories; and the identification of specific types of multidrug-resistant bacteria.
Most common Gram-negative pathogens
Antimicrobial resistance is a dynamic and multifaceted phenomenon, influenced by complex interactions between various factors. These factors include direct elements, such as antimicrobial misuse, as well as indirect factors, such as environmental pollution. The inherent characteristics of bacteria also play a significant role. Researchers have identified prior antibiotic exposure, underlying health conditions, and medical procedures as key risk factors associated with antibiotic resistance. Therefore, Gram-negative bacteria have become the primary cause of healthcare-associated infections (HAIs) in all the hospitals in Saudi Arabia. Besides the fact that their prevalence is extremely high in the ICUs, surgical departments, and organ transplant units, nowadays, these pathogens are not just getting more common but also more resistant, and the presence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains is increasing, as demonstrated in Table 1.
Table (1):
Gram-negative bacteria are the principal cause of infections that are acquired in healthcare settings
Organism |
Typical Infections |
Notes |
|---|---|---|
Escherichia coli |
UTIs, BSIs, wound infections |
Frequently ESBL-producing |
Klebsiella species |
Pneumonia, BSIs, UTIs |
Rising carbapenem resistance |
Pseudomonas species |
Respiratory, burns, device-associated infections |
High intrinsic resistance |
Acinetobacter species |
VAP, bloodstream, ICU infections |
Often XDR; outbreaks reported |
Enterobacter spp. |
BSIs, surgical wound infections |
Emerging resistance to cefepime |
Proteus spp. |
UTIs |
Less prevalent but often MDR |
Patient demographic and clinical characteristics
Bacteriological examination revealed the isolation of 960 organisms from clinical samples, including female and male 86 Fever samples, 148 Tracheal Aspirate C/S, 11 Catheter Tip Culture & Sensitivity samples, 16 Body Fluid-Drain Fluid C/S, 207 blood samples, 75 Respiratory infections, 84 Chest tightness, 132 Gastrointestinal symptoms, 122 Urine C/S and 77 Wound C/S. The results showed a diversity of samples, with blood cultures constituting the largest proportion at 21.5%. Furthermore, the inclusion of different sample types, such as urine samples, wound examinations, catheter tips, fever, and respiratory infections, demonstrates the rigor of the research methodology. Females were slightly more represented than males in most isolated samples (53.57% male, 46.43% female) as shown in Table 2.
Table (2):
Characteristics of Patients Sample type distribution of the patients in the study
Sample types |
No. of Isolates |
Percent(%) |
Female (%) |
Male (%) |
|---|---|---|---|---|
Fever |
86 |
8.9 |
44 (51.1%) |
42 (48.8%) |
Tracheal Aspirate C/S |
148 |
15.4 |
83 (56.1%) |
65 (43.9%) |
Catheter Tip Culture &Sensitivity |
13 |
1.3 |
8 (61.5%) |
5 (38.4%) |
Body Fluid-Drain Fluid C/S |
16 |
1.6 |
10 (62.5%) |
6 (37.5%) |
Blood Culture |
207 |
21.5 |
105 (50.7%) |
102 (49.2%) |
Respiratory infections. |
75 |
7.8 |
32 (42.6%) |
43 (57.3%) |
Chest tightness and shortness of breath |
84 |
8.7 |
45 (53.5%) |
39 (46.4%) |
Gastrointestinal symptoms (vomiting, diarrhea) |
132 |
13.7 |
69 (52.3%) |
63 (47.7%) |
Urine C/S |
122 |
12.7 |
64 (52.4%) |
58 (47.5%) |
Wound C/S |
77 |
8.01 |
43 (55.8%) |
34 (44.1%) |
Total |
960 |
100 |
514 (53.5%) |
446 (46.5%) |
Distribution and characteristics Gram-negative bacteria of isolated strains
Of the 960 isolated strains, the Gram-negative bacteria included Escherichia coli 310 (32.3%), Klebsiella spp. 233 (24.3%), Pseudomonas spp. 157 (16.3%), Acinetobacter spp. 114 (11.8%), Enterobacter spp. 80 (8.3%) and Proteus spp. 66 (6.8%). Table 3 shows the distribution of isolated bacteria among the different study samples. The results showed differences in bacterial prevalence across sample types. For example, urine samples showed a higher prevalence of Escherichia coli and Klebsiella spp. In contrast, tracheal aspiration (C/S) samples revealed a variety of bacteria, including Escherichia coli, Klebsiella spp., and Acinetobacter spp. Furthermore, blood cultures revealed the presence of various pathogens, most notably Escherichia coli and Klebsiella spp. Analysis of the samples showed that most of the bacterial organisms were of the types Escherichia coli Klebsiella spp. and Pseudomonas spp. that cause most infections and diseases.
Table (3):
Distribution of isolated Gram-negative bacteria among the different study samples
| Sample types | microorganism | Frequency | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Escherichia coli | Klebsiella spp. | Pseudomonas spp. | Acinetobacter spp. | Enterobacter spp. | Proteus spp. | ||||||||
| n | % | n | % | n | % | n | % | n | % | n | % | ||
| Fever | 22 | 25.5 | 15 | 17.4 | 31 | 36.1 | 7 | 8.1 | 8 | 9.3 | 3 | 3.4 | 86 |
| Tracheal Aspirate C/S | 38 | 25.6 | 37 | 25 | 20 | 13.5 | 32 | 21.6 | 12 | 8.1 | 9 | 6.1 | 148 |
| Catheter Tip & Sensitivity | 2 | 18.2 | 4 | 36.3 | 3 | 27.2 | 0 | 0 | 1 | 9.1 | 1 | 9.1 | 11 |
| Body Fluid-Drain | 3 | 18.7 | 9 | 56.2 | 4 | 25 | 0 | 0 | 0 | 0 | 0 | 0 | 16 |
| Blood Culture | 65 | 31.4 | 49 | 23.6 | 37 | 17.8 | 16 | 7.7 | 25 | 12.1 | 15 | 7.2 | 207 |
| Respiratory infections. | 10 | 13.3 | 20 | 26.6 | 21 | 28 | 7 | 9.3 | 11 | 14.6 | 6 | 8 | 75 |
| Chest tightness and breath | 29 | 34.5 | 17 | 20.2 | 6 | 7.1 | 11 | 13.1 | 7 | 8.3 | 14 | 16.6 | 84 |
| Gastrointestinal symptoms | 55 | 41.6 | 19 | 14.3 | 22 | 16.6 | 18 | 13.6 | 7 | 5.3 | 11 | 8.3 | 132 |
| Urine C/S | 49 | 40.1 | 42 | 34.4 | 9 | 7.4 | 17 | 13.9 | 3 | 2.4 | 2 | 1.6 | 122 |
| Wound C/S | 35 | 45.4 | 21 | 27.2 | 4 | 5.2 | 6 | 7.8 | 6 | 7.8 | 5 | 6.4 | 77 |
| total | 310 | 32.3 | 233 | 24.3 | 157 | 16.3 | 114 | 11.8 | 80 | 8.3 | 66 | 6.8 | 960 |
Distribution of isolated clinical bacteria by patient’s age
Table 4 shows the distribution of bacteria isolated in the study according to patient age. The results showed that some bacteria, particularly Klebsiella spp. 144 (50.5%) and Acinetobacter spp. 133 (46.1%), exhibited a significant increase in prevalence with advancing age, highlighting the likelihood of infection in elderly patients. Increases were also observed in middle-aged patients, but to a lesser extent in the elderly. Other bacterial isolates such as Enterobacter spp. 8 (13.7%) Proteus spp. 11 (14.6%) showed slight increases in younger age groups.
Table (4):
The percentage of prevalent bacteria isolated among different age groups of patients
| Organism isolated | <30 | 31-50 | 51-70 | Total | |||
|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | ||
| Escherichia coli | 12 | 11.7 | 41 | 40.1 | 49 | 48 | 102 |
| Klebsiella spp. | 57 | 20 | 84 | 29.4 | 144 | 50.5 | 285 |
| Pseudomonas spp. | 22 | 14.4 | 56 | 36.8 | 74 | 48.7 | 152 |
| Acinetobacter spp. | 45 | 15.6 | 110 | 38.2 | 133 | 46.1 | 288 |
| Enterobacter spp. | 8 | 13.7 | 18 | 31.1 | 32 | 55.1 | 58 |
| Proteus spp. | 11 | 14.6 | 27 | 36.0 | 37 | 49.3 | 75 |
| Total | 155 | 16.1 | 336 | 35.0 | 469 | 48.8 | 960 |
Patient Demographics and bacterial composition
Table 5 shows the results of different age groups in relation to infection with different types of bacteria. Patients aged between 30 and 70 years were the most susceptible to infection with Klebsiella bacteria, followed by Escherichia coli, then Acinetobacter spp., and then Klebsiella spp. Females were more susceptible than males in most infections, particularly Klebsiella spp. female 157 (55.1%) and male 128 (44.9%) and Pseudomonas spp. accounting female 81 (53.2%) and male 71 (46.7%), Conversely, Enterobacter spp. In the age group of males over 30 years old Lowest value (25.0%) and Proteus spp. In the age group of males 30-70 years old (27.7) was less common among males than females.
Table (5):
Demographic Characteristics of Patients with Bacterial Infections
| Organism isolated | <30 | 31-50 | 51-70 | Total | ||||
|---|---|---|---|---|---|---|---|---|
| Female number and percentage | Male number and percentage | Female number and percentage | Male number and percentage | Female number and percentage | Male number and percentage | Female number and percentage | Male number and percentage | |
| Escherichia coli | 7 (58.3%) | 5 (41.6%) | 23 (56.1%) | 18 (43.9%) | 29 (59.1%) | 20 (40.8%) | 59 (57.8%) | 43 (42.1%) |
| Klebsiella spp. | 32 (56.1%) | 25 (43.8%) | 46 (54.7%) | 38 (45.2%) | 79 (54.8%) | 65 (45.1%) | 157 (55.1%) | 128 (44.9%) |
| Pseudomonas spp. | 12 (54.5%) | 10 (45.4%) | 30 (53.5%) | 26 (46.4%) | 39 (52.7%) | 35 (47.2%) | 81 (53.2%) | 71 (46.7%) |
| Acinetobacter spp. | 23 (51.1%) | 22 (48.8%) | 59 (53.6%) | 51 (46.3%) | 74 (55.6%) | 50 (37.5%) | 156 (54.1%) | 132 (45.8%) |
| Enterobacter spp. | 6 (75.0%) | 2 (25.0%) | 13 (72.2%) | 5 (27.7%) | 18 (56.2%) | 14 (43.7%) | 37 (63.7%) | 21 (36.2%) |
| Proteus spp. | 6 (54.5%) | 5 (45.4%) | 18 (66.6%) | 9 (33.3%) | 21 (56.7%) | 16 (43.2%) | 45 (60.0%) | 30 (40.0%) |
Prevalent bacteria isolated among different multidrug-resistant groups in the study
In the event that a group of 960 Gram-negative bacilli (GNBs) were isolated, with E. coli being the predominant group, comprising 310 isolates (32.3%). Among these, 106 (34.1%) exhibited resistance. including 85 (80.1%) (MDR). isolates, 12 (11.3%) (XDR) isolates and 9 (8.4%) (PDR) isolates. Klebsiella spp. represented 233 (24.3%) of the isolates, with 108 (46.3%) exhibiting resistance, comprising 73 (67.5%) (MDR) isolates, 19(17.5%) (XDR) isolates and 16 (14.8%) (PDR) isolates. Pseudomonas spp. exhibited 157 isolates (16.3%), of which 124 (78.9%) were resistant, comprising 84 (67.7%) (MDR) isolates, 24 (19.3%) (XDR) isolates and 16 (12.9%) (PDR) isolates. Acinetobacter spp. accounted for 114(11.9%) isolates, of which 96 (84.2%) were resistant, comprising 64 (66.6%) (MDR) isolates, 21 (21.8%) (XDR) isolates and 11 (11.4%) (PDR) isolates. Enterobacter and Proteus spp. made up 80 (8.3%) and 66 (6.8%) of the isolates, and were more (MDR) (80.9) and (50.0) than both (XDR) and (PDR) as shown in Table 6.
Table (6):
The Number and percentage of prevalent bacteria isolated among different multidrug-resistant groups strains of respective bacteria
Organisms isolated |
No. of Isolates |
MDR (%) |
XDR (%) |
PDR (%) |
Total resistant isolates |
|---|---|---|---|---|---|
Escherichia coli |
310 (32.3) |
85 (80.1) |
12 (11.3) |
9 (8.4) |
106 (34.1) |
Klebsiella spp. |
233 (24.3) |
73 (67.5) |
19 (17.5) |
16 (14.8) |
108 (46.3) |
Pseudomonas spp. |
157 (16.3) |
84 (67.7) |
24 (19.3) |
16 (12.9) |
124 (78.9) |
Acinetobacter spp. |
114 (11.3) |
64 (66.6) |
21 (21.8) |
11 (11.4) |
96 (84.2) |
Enterobacter spp. |
80 (8.3) |
51 (80.9) |
8 (12.6) |
4 (6.3) |
63 (78.8) |
Proteus spp. |
66 (6.8) |
23 (50.0) |
15 (32.6) |
8 (17.3) |
46 (69.6) |
Total |
960 (100) |
380 (69.9) |
99 (18.2) |
64 (11.7) |
543 (56.5) |
Antibiotic resistance pattern among MDR, XDR and pDR Gram-negative isolates
Antibiotic resistance patterns showed higher resistance among both MDR, XDR and pDR groups. In the MDR group (n = 380), resistance was highest to Amikacin (61.2%), Colistin (55.2%), and Ciprofloxacin (51.5%), Resistance were lower in the XDR (n = 99) groups isolates resistance was highest to Amikacin (35.3%), Colistin (36.3 %), and Erythromycin (34.3%). However, the resistance in pDR was less than in MDR and higher than in XDR, reaching in each of the Amikacin (50.0%), Erythromycin (62.5%) and Ciprofloxacin (64.1%), However, the lowest values in the three groups were in each of MDR Ceftriaxone 32.8% and Gentamycin 27.1% XDR (Gentamycin 17.1% and Mupirocin 23.2%) and pDR(Moxifloxacin 23.4% and Mupirocin 43.5%) respectively as shown in Table 7.
Table (7):
Antibiotic Resistance Pattern among MDR, XDR and pDR Gram-negative Isolates
| Antibiotic | MDR resistance (n=380) | XDR resistance (n=99) | PDR resistance (n=64) | |||
|---|---|---|---|---|---|---|
| n | % | n | % | n | % | |
| Amikacin | 234 | 61.5 | 35 | 35.3 | 32 | 50.0 |
| Ampicillin | 178 | 46.8 | 29 | 29.2 | 25 | 39.1 |
| Cefotaxime | 191 | 50.2 | 26 | 26.6 | 27 | 42.1 |
| Ceftriaxone | 125 | 32.8 | 28 | 28.2 | 34 | 53.1 |
| Ciprofloxacin | 196 | 51.5 | 25 | 25.2 | 41 | 64.1 |
| Colistin | 210 | 55.2 | 36 | 36.3 | 28 | 43.7 |
| Erythromycin | 119 | 31.3 | 34 | 34.3 | 40 | 62.5 |
| Gentamycin | 103 | 27.1 | 17 | 17.1 | 33 | 51.2 |
| Levofloxacin | 174 | 45.7 | 18 | 18.1 | 49 | 76.5 |
| Moxifloxacin | 186 | 48.9 | 30 | 30.3 | 15 | 23.4 |
| Mupirocin | 159 | 41.8 | 23 | 23.2 | 28 | 43.5 |
Major Gram-negative bacteria: comparative results for antimicrobial susceptibility
Bacterial resistance rates to antimicrobial agents vary significantly between different bacterial species, which are summarized in Table 8 as the mean resistance rates of the associated Gram-negative bacteria. With the discovery of multiple resistant strains, antibiotic susceptibility testing (Table 8). revealed different patterns of bacterial resistance. Antibiotic-resistant bacteria exhibited high resistance to amikacin, cefotaxime, and ampicillin, while levofloxacin, moxifloxacin, and mupirocin isolates showed lower resistance. Some bacteria exhibited the highest resistance to cefoxitin (79.6%) in Escherichia coli, followed by ciprofloxacin (77.1%) in Pseudomonas aeruginosa. The lowest resistance was observed to levofloxacin (17.1%) in Escherichia coli, erythromycin (21.2%) in the same group, and mupirocin (21.6%) in Pseudomonas aeruginosa.
Table (8):
Number and rates of resistance of clinical Gram-negative bacteria to common antibiotics
| Antibiotic | Microorganism | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Escherichia coli 310 | Klebsiella spp. (233) | Pseudomonas spp. (157) | Acinetobacter spp. (114) | Enterobacter spp. (80) | Proteus spp. (66) | |||||||
| n | % | n | % | n | % | n | % | n | % | n | % | |
| Amikacin | 173 | 55.8 | 171 | 73.3 | 123 | 78.3 | 63 | 55.2 | 66 | 82.5 | 33 | 50.0 |
| Ampicillin | 145 | 46.7 | 129 | 55.3 | 117 | 74.5 | 54 | 47.3 | 33 | 41.2 | 42 | 63.6 |
| Cefotaxime | 247 | 79.6 | 188 | 80.6 | 108 | 68.7 | 61 | 53.5 | 32 | 40.0 | 41 | 62.1 |
| Ceftriaxone | 98 | 31.6 | 120 | 51.5 | 72 | 45.8 | 44 | 38.5 | 27 | 33.7 | 24 | 36.3 |
| Ciprofloxacin | 97 | 31.2 | 83 | 35.6 | 121 | 77.1 | 39 | 34.2 | 18 | 22.5 | 29 | 43.9 |
| Colistin | 33 | 10.6 | 91 | 39.0 | 47 | 29.9 | 47 | 41.2 | 16 | 20.0 | 36 | 54.5 |
| Erythromycin | 66 | 21.2 | 87 | 37.3 | 32 | 20.3 | 38 | 33.3 | 16 | 20.0 | 35 | 53.0 |
| Gentamycin | 79 | 25.4 | 77 | 33.0 | 109 | 69.4 | 59 | 51.7 | 23 | 28.7 | 39 | 59.1 |
| Levofloxacin | 55 | 17.7 | 95 | 40.7 | 97 | 61.7 | 28 | 24.5 | 26 | 32.5 | 28 | 42.4 |
| Moxifloxacin | 131 | 42.2 | 62 | 26.6 | 43 | 27.3 | 42 | 36.8 | 25 | 31.2 | 31 | 46.9 |
| Mupirocin | 88 | 28.3 | 51 | 21.8 | 34 | 21.6 | 29 | 25.4 | 23 | 28.7 | 27 | 40.9 |
The existence of Gram-negative multidrug-resistant (MDR) bacteria has evolved into a serious concern for the world health due to the fact that they are now frequently found in hospitals. An example of such bacteria is Escherichia coli, Klebsiella species, Proteus species, and Citrobacter species which have acquired resistance against the greater part of the antibiotics thus the only options left are the ones that are less effective making the situation worse in the aspect of treatment failure and death.13 It was stated that the bacteria belong to the Gram-negative bacteria group, an order called Enterobacteriaceae.14 Certain microorganisms, including yeasts, have evolved significant resistance to a wide range of antimicrobial agents employed in human medicine.15 The increasing prevalence of these resistant bacteria represents a substantial and growing concern, with recent investigations indicating that approximately 30% of community-acquired infections now exhibit resistance to commonly prescribed antibiotics.16 Addressing antimicrobial resistance in humans requires a comprehensive and multidisciplinary approach. Given the high potential for human-to-human transmission, antimicrobial resistance should be addressed across all populations.17 Accordingly, a systems-oriented perspective within ecological contexts is essential and constitutes a fundamental component of antimicrobial stewardship (AMS) initiatives designed to promote judicious antimicrobial utilization in human populations.18 Furthermore, some studies have been published indicating an increase in cases of antibiotic hypersensitivity syndrome in humans. However, information regarding the isolation, resistance, and susceptibility patterns of bacteria remains very limited.19
Multiple-drug-resistant bacterial strains have emerged throughout the previous years while Gram-negative pathogens now display universal drug resistance according to research.20 The bacteria received their name because they demonstrate resistance to three or more antimicrobial drug classes according to laboratory results. The World Health Organization (WHO) has released antibiotic-resistant pathogen lists which include critical bacteria such as carbapenem-resistant Acinetobacter and Pseudomonas aeruginosa.21 The drug resistance mechanisms can be classified into several main groups such as the production of ESBL enzymes, the modification of aminoglycosides, the action of chloramphenicol acetyltransferase, and changes in the cell permeability which ultimately results in reduced drug accumulation inside the bacteria. Recent studies on the distribution pattern of antimicrobial resistance have revealed a sharp increase in resistant infections particularly in intensive care units. Patients in these units are more susceptible to infection due to undergoing various surgical procedures. Furthermore, many of the medications used may suppress their immune response.22
In this study, which analyzed 960 Gram-negative bacterial samples, the most valuable isolates came from blood cultures, tracheal aspiration, gastrointestinal symptoms, and urinary tract examinations, respectively, while the least valuable came from catheter tip cultures and fluid drainage. Samples of concern regarding bacterial infection, such as urine samples, were the most common source, totaling 122 samples (12.7%), with females predominating (64 samples) (52.4%), consistent with the known epidemiology of urinary tract infections. Wound examinations accounted for 77 samples (8.01%), with the majority of these being female 43 samples (55.8%). This is likely due to trauma and postoperative wound infections. Respiratory tract infection samples yielded 75 cases (7.8%), with a high proportion being male (43 samples, 57.3%), suggesting a higher incidence of respiratory tract infections among males, possibly due to occupational exposure. Blood contributed to 207 samples (21.5%), the highest proportion among isolated samples, with similar proportions between the sexes, indicating more severe infections, such as sepsis, in both sexes. These findings are consistent with observations confirming the presence of Gram-negative bacteria in critical care settings.23,24
The distribution of pathogens revealed that Escherichia coli was the most frequently isolated organism, with 310 isolates (32.3%), followed by Klebsiella spp. (233 isolates) (24.3%), Pseudomonas spp. (157 isolates) (16.3%), and Acinetobacter spp. (114 isolates) (11.3%). These species are common pathogens of community- and hospital-acquired infections, particularly urinary tract and lower respiratory tract infections. They were primarily isolated from respiratory tract and wound specimens. Proteus spp. (66 isolates) (6.8%) and Enterobacter spp. (80 isolates) (8.3%) were less frequently isolated. This distribution reflects a pattern of Gram-negative bacteria in healthcare facilities, where antagonistic bacteria predominate.25
Research conducted earlier by Samonis et al.26 showed that Pseudomonas spp. and Escherichia coli and Klebsiella spp. were the dominant bacterial species found in the adult intensive care unit of a tertiary care hospital based in Riyadh, Saudi Arabia.27 The bacteria identified in this study match the typical bacterial infections doctors encounter during routine medical practice. The research results match those from a Riyadh-based study conducted by Alkofide et al.28 The study identified urine as the primary source of infection. The combination of medical factors including urinary catheter placement and pre-existing conditions and anatomical differences in patients makes them more susceptible to urinary tract infections which leads to increased positive test results from urine samples.
The results of this study showed that some bacteria become more prevalent with age, highlighting the potential for infection in elderly patients. Increases were also observed in middle-aged patients, but to a lesser extent in the elderly. Other bacterial isolates showed slight increases in younger age groups. Patients aged 30-70 years were most susceptible to Klebsiella, followed by Escherichia coli, and then Acinetobacter. Females were more susceptible than males in most cases. A study conducted in Saudi Arabia.29 On the other hand, another study revealed that the female infection rate was higher than that of males.30 Such variability is not simple to explain and should thus be seen in light of differences in sample collection procedures, study design, sample characteristics, inclusion of patients in the study, the settings and the hygiene procedures used.
One of the most important discoveries from the research was that of the great antimicrobial resistance tendency. Among the 960 Gram-negative isolates, 380 (69.9%) were identified as multidrug-resistant (MDR), while 99 (18.2%) were classified as extensively drug-resistant organisms (XDR). Only 64 (11.7%) were susceptible to severe pandrug resistant (PDR). This resistance has been internationally defined by the classification proposed by Magiorakos et al.31 and reflects a worrying trend in resistance.
The situation in Makkah has been highlighted by these findings, which are a clear indicator of the increasing problem of microbial resistance and the necessity of prompt public health interventions of a specific nature. Our figure of multidrug-resistance was greater than that found in other parts of Saudi Arabia, but the figure for severe and complete drug resistance was comparably lower. As an instance, a research by Alnour et al.32 in northwestern Saudi Arabia gave prevalence rates of 33.4%, 29.3%, and 12.4%, respectively. The large presence of the multidrug resistance phenomenon can be linked to antibiotic usage on a large scale, since antibiotics are the main factor that creates a more favorable environment for resistant strains to appear and spread among the bacterial populations.33 On the other hand, though, Acinetobacter spp. isolates showed the highest prevalence of XDR and PDR phenotypes among all the bacteria tested, where 54% and 46% of the isolates were found to be XDR and PDR, respectively. These numbers are much greater than those of Said et al.34 who reported 35% and 3% for XDR and PDR, respectively. Moreover, Acinetobacter spp is capable of acquiring multidrug-resistance due to its intrinsic mechanisms of resistance and diverse genetic makeup.35
In the same way, Escherichia coli and Klebsiella spp. got samples which showed a high level of multipledrug-resistance (MDR) and contained in addition the XDR and PDR phenotypes. The level of multiple drug resistance in Klebsiella spp. was even higher than what was documented by Hafiz et al.36 Klebsiella spp. ability to acquire and spread resistance genes is what accounts for the development of the strains which are multidrug-resistant. Pseudomonas spp. isolates also exhibited a high level of the multipledrug- resistant strains as documented by Ibrahim.37 Pseudomonas spp. is known to have a high level of resistance to a number of antibiotics and this resistance can increase by various ways including the development of efflux pumps and biofilms.38,39
Within the scope of our investigation into the sensitivity of laboratory-derived microbial strains to a range of antimicrobial compounds, we have characterized an organism as exhibiting multidrug resistance when demonstrating insensitivity to a minimum of three distinct antimicrobial agents. Antibiotic susceptibility testing revealed different patterns of bacterial resistance. Antibiotic-resistant bacteria showed high resistance to amikacin, cefotaxime, and ampicillin, while levofloxacin, moxifloxacin, and mupirocin isolates showed lower resistance. The same result was recorded in a study which was published by Silva et al.40 Resistance in Proteus and Escherichia coli strains was very low in comparison to the first group.
Some bacteria showed the highest resistance to cefoxitin (79.6%) in Escherichia coli, followed by ciprofloxacin (77.1%) in Pseudomonas aeruginosa. The lowest resistance to levofloxacin (17.1%) was observed in Escherichia coli, erythromycin (21.2%) in the same group, and mupirocin (21.6%) in Pseudomonas aeruginosa. Studies by Narten et al.41 reported that cefotaxime resistance to Escherichia coli (24%-54%) was high in Staphylococcus aureus, while high resistance to aminoglycosides was observed in 53.3% of Enterococcus species in the same study. It has been suggested that the higher amounts of resistant bacteria in Saudi Arabia are the result of the country’s escalating antibiotic consumption.42 A research study was carried out in Mecca, where it was found that the rate of resistance among Gram-negative bacteria was much higher than in other countries around the world, thus making a surveillance program to monitor the situation necessary. Therefore, implementing a national antibiotic policy and guidelines is a critical step in curbing the occurrence of multidrug-resistance as well as keeping the resistance to modern antibiotics in Saudi Arabia at a low level.43
The current research has drawn attention to the existence of multidrug-resistant and extensively drug resistant Gram-negative bacilli in clinical samples, posing a major challenge for the antibiotic treatment to be effective. It points out the necessity of strict sanitary measures and efficient antimicrobial management programs. Timely detection and careful antibiotic use are still vital in containing the resistant pathogens’ spread. It would be a good idea to carry out more studies including a national project to check the susceptibility of Gram-negative bacteria from hospitals and health centers in Makkah. Additionally, knowing the resistance mechanisms of these bacteria will be helpful for marking their distribution within the study area.
ACKNOWLEDGMENTS
The author expresses his sincere gratitude to Al-Noor Hospital in Makkah, Saudi Arabia, for their support.
FUNDING
None.
DATA AVAILABILITY
All datasets generated or analyzed during this study are included in the manuscript.
ETHICS STATEMENT
The study was approved by the Medical Research Ethical Committee, Umm Al-Qura University, Saudi Arabia (application number BIBB060326).
INFORMED CONSENT
Written informed consent was obtained from the participants before enrolling in the study.
- Bush K, Bradford PA. Interplay between β-lactamases and new β-lactamase inhibitors. Nat Rev Microbiol. 2019;17(5):295-306.
Crossref - Codjoe FS, Donkor ES. Carbapenem Resistance: A Review. Medical Sciences. 2018; 6(1):1.
Crossref - Hickson SM, Ledger EL, Wells TJ. Emerging antimicrobial therapies for Gram-negative infections in human clinical use. NPJ Antimicrob Resist. 2025;3:16.
Crossref - Somily AM, Habib HA, Absar MM, et al. ESBL-producing Escherichia coli and Klebsiella pneumoniae at a tertiary care hospital in Saudi Arabia. J Infect Dev Ctries. 2014;8(9):1129-1136.
Crossref - Memish ZA, Shibl AM, Kambal AM, Ohaly YA, Ishaq A, Livermore DM. Antimicrobial resistance among non-fermenting Gram-negative bacteria in Saudi Arabia. J Antimicrob Chemother. 2012;67(7):1701-1705.
Crossref - Sterne JAC, Savovic J, Page MJ, et al. RoB 2: A revised tool for assessing risk of bias in randomised trials. BMJ. 2019;366:4898.
Crossref - Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing. 30th ed. Wayne (PA): CLSI; 2020. (CLSI supplement M100).
- Eubank TA, Long SW, Perez KK. Role of rapid diagnostics in diagnosis and management of patients with sepsis. J Infect Dis. 2020;222(Suppl 2):S103-S109.
Crossref - Tacconelli E, Magrini N, Eds. Global priority list of antibiotic-resistant bacteria to guide research, discovery, and development of new antibiotics. Geneva: World Health Organization. 2017. https://storagehub.homnya.net/cmsimage/allegati/allegato4135670.pdf
- DerSimonian R, Laird N. Meta-analysis in clinical trials. Control Clin Trials. 1986;7(3):177-188.
Crossref - Alshehri AA, Aldali JA, Abdelhamid MA, et al. Implementation of antimicrobial stewardship programs in Saudi Arabia: A systematic review. Microorganisms. 2025;13(2):440.
Crossref - Al-Abdely H, Alhababi R, Dada HM, et al. Molecular characterization of carbapenem-resistant Enterobacterales in thirteen tertiary care hospitals in Saudi Arabia. Ann Saudi Med. 2021;41(2):63-70.
Crossref - Yassin A, Huralska M, Pogue JM, Dixit D, Sawyer RG, Kaye KS. Executive Summary: State-of-the-Art Review: State of the Management of Infections Caused by Multidrug-Resistant Gram-Negative Organisms. Clin Infect Dis.2023;77(9):1223-1225.
Crossref - de Angelis G, D’Inzeo T, Fiori B, Spanu T, Sganga G. Burden of Antibiotic-Resistant Gram Negative Bacterial Infections: Evidence and Limits. J Med Micro Diag. 2024;3(1):132-138.
Crossref - Teklu DS, Negeri AA, Legese MH, Bedada TL, Woldemariam HK, Tullu KD. Extended-Spectrum Beta-Lactamase Production and Multi-Drug Resistance among Enterobacteriaceae Isolated in Addis Ababa, Ethiopia. Antimicrob Resist Infect Control. 2019;8:39.
Crossref - Bassetti M, Garau J. Current and Future Perspectives in the Treatment of Multidrug-Resistant Gram-Negative Infections. J Antimi Chemo. 2021;76(Suppl 4):iv23-iv37.
Crossref - Mendelson M, Matsoso MP. The World Health Organization Global Action Plan for antimicrobial resistance. S Afr Med J. 2015;105(5):325.
Crossref - Saleem Z, Godman B, Cook A, et al. Ongoing Efforts to Improve Antimicrobial Utilization in Hospitals among African Countries and Implications for the Future. Antibiotics. 2022;11(12):1824.
Crossref - Mudenda S, Chomba M, Chabalenge B, et al. Antibiotic Prescribing Patterns in Adult Patients According to the WHO Aware Classification: A Multi-Facility Cross-Sectional Study in Primary Healthcare Hospitals in Lusaka, Zambia. Pharma.2023;2(1):42-53;
Crossref - Nagvekar V, Sawant S, Amey S. Prevalence of multidrug-resistant Gram-negative bacteria cases at admission in a multispeciality hospital. J Glob Antimicrob Resist.2020:22:457-461.
Crossref - van Duong TT, Thang N, van Truyen N, Minh TVP. Prevalence and determinants of antimicrobial resistance of gramnegative bacteria in intensive care unit. Pharm Sci Asia. 2022;49(6):568-575.
Crossref - Anderson DJ, Jenkins TC, Evans SR, et al. The role of stewardship in addressing antibacterial resistance: stewardship and infection control committee of the antibacterial resistance leadership group. Clin Infect Dis. 2017;64(suppl_1):S36-S40.
Crossref - Lachhab Z, Frikh M, Maleb A, et al. Bacteraemia in Intensive Care Unit: Clinical, Bacteriological, and Prognostic Prospective Study. Can J Infect Dis Med Microbiol. 2017;2017:4082938.
Crossref - Agyepong N, Govinden U, Owusu-Ofori A, Essack SY. Multidrug-resistant Gram-negative bacterial infections in a teaching hospital in Ghana. Antimicrob Resist Infect Control. 2018;7:37.
Crossref - Kindu M, Derseh L, Gelaw B, Moges F. Carbapenemase-producing non-glucose-fermenting Gram-negative bacilli in Africa, Pseudomonas aeruginosa and Acinetobacter baumannii: a systematic review and meta-analysis. Int J Microbiol. 2020;2020:9461901.
Crossref - Samonis G, Maraki S, Rafailidis PI, Kapaskelis A, Kastoris AC, Falagas ME. Antimicrobial susceptibility of Gram-Negative nonurinary bacteria to fosfomycin and other antimicrobials. Future Microbiology. 2010;5(6):961-970.
Crossref - Al Johani SM, Akhter J, Balkhy H, El-Saed A, Younan M, Memish Z. Prevalence of antimicrobial resistance among gram-negative isolates in an adult intensive care unit at a tertiary care center in Saudi Arabia. Ann Saudi Med. 2010;30(5):364-369.
Crossref - Alkofide H, Alhammad AM, Alruwaili A, et al. Multidrug-resistant and extensively drugresistant enterobacteriaceae: prevalence, treatments, and outcomes—a retrospective cohort study. Infect Drug Resist. 2020:13:4653-4662.
Crossref - Samah G, El Shafey HM, El Kelani AT, Nikhat M. Antimicrobial resistance patterns of Klebsiella isolates from clinical samples in a Saudi hospital. Afr J Microbiol Res. 2017;11(23):965-971.
Crossref - Maity SN, Marothi Y, Pradhan R, Waske S, Hemwani K. Antimicrobial suscep tibility pattern of Klebsiella pneumoniae isolated from various clinical speci mens in Ujjain City, Madhya Pradesh, India. Cent India J Med Res. 2022;1(01).
Crossref - Magiorakos AP, Srinivasan A, Carey RB, et al. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect. 2012;18(3):268-281.
Crossref - Alnour TM, Elssaig E, Albalawi T, et al. Phenotypic and genotypic characterization of antibiotic resistant gram negative bacteria isolated in Tabuk City, Saudi Arabia. Afr J Microbiol Res. 2021;15(8):433-439.
Crossref - Wani FA, Bandy A, Alenzi MJS, et al. Resistance patterns of Gram-negative bacteria recovered from clinical specimens of intensive care patients. Microorganisms. 2021;9(11):2246.
Crossref - Said KB, Alsolami A, Khalifa AM, et al. A multi-point surveillance for antimicrobial resistance profiles among clinical isolates of Gram-negative bacteria recovered from major Ha’il hospitals, Saudi Arabia. Microorganisms. 2021;9(10):2024.
Crossref - Akinjogunla OJ, Adefiranye OO, Edem EN, Adenugba IT, Ogboona FC, Oshosanya GO. Antibiotic resistance profile, multidrug-, extensively drug-, and pandrug-resistant bacterial isolates: hemagglutination and hemolytic activities against human erythrocytes. Proc Natl Acad Sci India Sect B Biol Sci. 2024.
Crossref - Hafiz TA, Alghamdi SS, Mubaraki MA, Alghamdi SSM, Alothaybi A, Aldawood EA, et al. A two-year retrospective study of multidrug-resistant Acinetobacter baumannii respiratory infections in critically ill patients: clinical and microbiological findings. J Infect Public Health. 2023;16(3):313-319.
Crossref - Ibrahim ME. Risk factors in acquiring multidrug-resistant Klebsiella pneumoniae infections in a hospital setting in Saudi Arabia. Sci Rep. 2023;13(1):11626.
Crossref - Hafiz TA, Bin Essa EA, Alharbi SR, et al. Epidemiological, microbiological, and clinical characteristics of multi-resistant Pseudomonas aeruginosa isolates in King Fahad Medical City, Riyadh, Saudi Arabia. Trop Med Infect Dis. 2023;8(4):205.
Crossref - Bessa LJ, Fazii P, Di Giulio M, Cellini L Bacterial isolates from infected wounds and their antibiotic susceptibility pattern: some remarks about wound infection. Int Wound J. 2015;12(1):47-52.
Crossref - Silva V, Marcoleta A, Silva V, et al. Prevalence and susceptibility pattern of bacteria isolated from infected chronic wounds in adult patients. Rev Chil Infectol. 2018;35(2):155-162.
Crossref - Narten M, Rosin N, Schobert M, Tielen P. Susceptibility of Pseudomonas aeruginosa urinary tract isolates and influence of urinary tract conditions on antibiotic tolerance. Curr Microbiol. 2012;64(1):7-16.
Crossref - Ekrami A, Kalantar E. Bacterial infections in burn patients at a burn hospital in Iran. Indian J Med Res. 2007;126(6):541-544
- Asghar AH, Faidah HS. Frequency and antimicrobial susceptibility of Gram-negative bacteria isolated from 2 hospitals in Makkah, Saudi Arabia. Saudi Med J. 2009;30(8):1017-1023.
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