الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 161 |  |  |
| | | from | 161 | | |
Abstract
The study included clinical samples collected from 494 patients in 3 groups aged from 5 days to 75 years, 258 patients admitted to different departments and ICUs of Menoufia University Hospitals in group I, 138 admitted to different outpatient clinics in group II and 98 healthy peoples in group III.
All clinical (n=50) Enterobacter isolates were further studied for determination of antibiotic susceptibility patterns, detection of ESβL detection of class B (metallo β-lactamases) and detection of irp2 virulence gene.
It was found that;
The prevalence of Enterobacter infection was 10.10% in total samples, 12.4% (32/285) of them from hospital-acquired infections, 7.3% (10/138) from community-acquired infections and 8.2% (8/98) from carriers. The prevalence of Enterobacter infection among Gram –ve bacteria was 20.9%, 15.1% & 15.3% for hospital-acquired infections, community-acquired infections and carriers respectively.
Enterobacter infections were more common among the old age group 45-75 years (65.6%) for HAI, 60% for CAI and 50% for carriers without statistically significant difference (P> 0.05).
Males were more commonly affected by Enterobacter than females in both group I and group III and were equally affected in group II.
Enterobacter infections were more common among patients with co-morbidities, patients receiving antimicrobial agents and patients exposed to invasive procedures.
Summary
116
In HAI, the incidence of Enterobacter infection was high in patients with hospital stay duration (7:14 day).
Most Enterobacter isolates were from sputum samples (32%) followed by pus samples (24%) and urine samples (18%). In HAI (n=32) 40.6% Enterobacter isolates were from sputum samples followed by urine and pus samples (21.9 %) for each. In CAI (n=10), most Enterobacter isolates were from pus samples (50%) then sputum samples (30%) and urine samples (20%). All isolates in carriers were from stool (100%).
The highest isolation of Enterobacter spp. in hospital was from ICU (37.5%) followed by Chest department (31,3%), Urogenital department (15.6%), General surgery department (6.3%), Internal medicine departments and Dermatology (3.1%). Also, 30%, 30%, 20%, 10% and 10% of clinical community-acquired Enterobacter spp. were isloated from Chest, General surgery, Urogenital, Dermatology and Plastic surgery respectively.
Enterobacter cloacae was the predominant Enterobacter species (54.0%) followed by E. aerogenes (34.0%), E. agglomerans (8%) and E. sakazakii (4%).
Clinical hospitalized Enterobacter isolates were highly resistant to Ceftazidime, Cefepime, Ceftriaxone, Cefoxitin and Amoxicillin/Clavulanic acid (90% for each), Amoxicillin (93.8%), Piperacillin/Tazobactam (83.5%), Cefeprazone (87.5%) and Aztreonam (71.9%).
Fifty percent of them were resistant to Ofloxacin and Norfloxacin, 62.5% to Doxycycline, 56.3 % to Trimethoprim/Sulfamethoxazole and 34.4% to Tobramycin. The resistance to Imipenem, Meropenem, Ertapenem, was 59.4% for each.
Summary
117
On the other hand, 58.3 %, 78.1% and 71.9% of the clinical Enterobacter isolates respectively were susceptible to Amikacin, Choloramphinecol and Tigecycline.
Outpatient Enterobacter isolates were highly resistant to Amoxicillin (100%), Ceftazidime, Cefepime and Aztreonam (70% for each), Ceftriaxone and Cefeprazone (80% for each), Cefoxitin (50%), Amoxicillin/Clavulanic acid (70%) and Piperacillin/Tazobactam (30%), The resistance to Imipenem and Meropenem were 40% while it was 50% for Ertapenem. On the other hand, 60% of the clinical Enterobacter isolates were susceptible to Amikacin, Choloramphinicol, 50% to Ofloxacin and Doxycycline and 70% to Tigecycline.
Enterobacter isolates were tested phenotypically for ESβLs production by disk diffusion screening test and showed that 90.6%, 80% and 75% of HAI, CAI and carrier isolates were potential ESβLs producers. On other hand, only (75 %, 70% and 62.5%) of HAI, CAI and carrier isolates were confirmed to be ESβLs producers by using Cephalosporins/Clavulanate combination test without statistical significant difference.
Our study, showed that most of the isolated Enterobacter (78.1%, 70% and 62.5%) of HA, CA and carrier isolates were potential MβL producers by screening method depending on resistance to Imipenem with specific inhibition zone diameter for MβL detection. While, only (62.5%, 50% and 37.5%) of HA, CA and carrier isolates were confirmed to be MβL producers by using combined Imipenem/EDTA synergy test without statistical significant difference between the three groups.
Summary
118
This study showed that, 21/32 (65.6%) of the hospital-acquired Enterobacter isolates had irp2 gene by conventional PCR, 4/10 (40%) of the community Enterobacter isolates had the gene while only 2/8 (25%) of the carrier isolates had the gene with statistical significant difference (P<0.05) between HAI and carriers.
This study showed that, among HAI group (85.7%) of Enterobacter having irp2 virulence gene were ESβLs producers by using combined disk method and MβL producers by using combined Imipenem /EDTA synergy test while 54.5% of Enterobacter that didn‟t have irp2 virulence gene were ESβLs producers by using combined disk method and 18.2% Enterobacter that didn‟t have irp2 virulence gene were MβL producers by using combined Imipenem/EDTA synergy test with highly statistical significant difference (P<0.001).
This study showed that, among CAI group 4/4 (100%) of Enterobacter having irp2 virulence gene were ESβLs producers by using combined disk method and MβL producers by using combined Imipenem/EDTA synergy test while 50% Enterobacter that didn‟t have irp2 virulence gene were ESβLs producers by using combined disk method and 16.7% Enterobacter that didn‟t have irp2 virulence gene were MβL producers by using combined Imipenem/EDTA synergy test.
This study showed that, among carrier group, 2/2 (100%) of Enterobacter having irp2 virulence gene were ESβLs producers by using combined disk method and MβL producers by using combined Imipenem/EDTA synergy test while 50% of Enterobacter that didn‟t have irp2 virulence gene were ESβLs producers by using combined disk method and 16.7% of Enterobacter that didn‟t have irp2
Summary
119
virulance gene were MβL producers by using combined Imipenem/EDTA synergy test.
This study showed that, among 27 Enterobacter isolates that had irp2 virulence gene 17 (63%) were E. cloacae, 8 (29.6%) were E. aerogenes, 1 (3.7%) were E. agglomerans and E. sakazakii respectively.
By ESβL confirmatory and carbapenamase confirmatory test, of irp2 virulence gene was detected in 85.7% of HAI group, 100% in CAI group and in 62.5% in carrier group.
As regard presence of carbapenamase among HAI group, it was detected in 35.7% in E. aerogenes, 32.1% in E. cloacae and in 3.6% in E. sakazakii. While in CAI, it was detected in 14.3% of E. cloacae, and in 3.6% in E. agglomerans. Finally in carrier group, it was detected in 10.7% in E. cloacae species.
In HAI group, presence of ESβL species was in 35.7% of E. aerogenes, 17.1% in E. agglomerans, 14.3% in E. cloacae. While in CAI, ESβL producing strains were 14.3% in E. aerogenes and 7.1% in E. cloacae and in carriers group, ESβL producing strians were in 14.3% of E. cloacae and 7.1% in E. aerogenes.
In HAI group, irp2 virulence gene of the isolated Enterobacter was detected in 52.4% of sputum sample, 23.8% of urine, 19% of pus and 4.8% of blood samples. While in CAI, the majority of gene-positive strains were detected in pus samples (75%) and (25%) in sputum samples. Finally, in carrier group, irp2 virulence gene of the isolated Enterobacter was detected in 100% of stool samples.
Summary
120
In conclusion;
The frequency of isolation of Enterobacter species from clinical specimens obtained from patients admitted to the different departments and ICUs of Menoufia University Hospitals was higher than community cases carriers. Virulence and remarkable drug resistance of the organisms make them clinically significant pathogens.
Enterobacter spp. from normal microbiota and from hospital and community-acquired infections have important virulence factors for the establishment of extraintestinal infections.
Prolonged hospital stay, especially in an ICU, the presence of a serious underlying illness and immunosuppression from any cause, the presence of a foreign device and prior use of anti-microbial agents were risk factors for Enterobacter infection.
The frequency of ESBLs and MBLs producing strains among clinical isolates is increasing
The presence of irp2 gene in Enterobacter isolates analyzed here is an indicative of the importance of these bacteria as human pathogens with potential to cause exraintestinal infections.
The accumulation of virulence genes responsible for the synthesis of yersiniabactin siderophore in positive Enterobacter isolates, together with the antimicrobial multiresistance observed in this study, impose significant therapeutic limitations on the treatment of infections caused by Enterobacter.