Multidrug resistance Acinetobacter species at the intensive care unit，Aseer Central Hospital， Saudi Arabia： A one year analysis

Ali Al Bshabshe， Martin R.P. Joseph， Ali Al Hussein， Waleed Haimour， Mohamed E. Hamid*

1Department of Medicine， College of Medicine， King Khalid University， Abha， Kingdom of Saudi Arabia

2Department of Microbiology， College of Medicine， King Khalid University， Abha， Kingdom of Saudi Arabia

3Intensive Care Unit， Aseer Central Hospital， Abha， Kingdom of Saudi Arabia

4Microbiology Laboratories， Aseer Central Hospital， Abha， Kingdom of Saudi Arabia

Multidrug resistance Acinetobacter species at the intensive care unit，Aseer Central Hospital， Saudi Arabia： A one year analysis

Ali Al Bshabshe1， Martin R.P. Joseph2， Ali Al Hussein3， Waleed Haimour4， Mohamed E. Hamid2*

1Department of Medicine， College of Medicine， King Khalid University， Abha， Kingdom of Saudi Arabia

2Department of Microbiology， College of Medicine， King Khalid University， Abha， Kingdom of Saudi Arabia

3Intensive Care Unit， Aseer Central Hospital， Abha， Kingdom of Saudi Arabia

4Microbiology Laboratories， Aseer Central Hospital， Abha， Kingdom of Saudi Arabia

ARTICLE INFO

Article history:

Received 15 May 2016

Received in revised form 16 June 2016

Accepted 1 July 2016

Available online 20 September 2016

Acinetobacter spp.

Objective: To identify and to determine the antimicrobial susceptibility of Acinetobacter baumannii （A. baumannii） clinical isolates from ICU at Aseer Central Hospital. Methods: The study was conducted in the Intensive Care Unit， Aseer Central Hospital， Saudi Arabia over 13 months period （2014-2015）. Acinetobacter species （n= 105） were isolated from various clinical samples. Isolates were identif i ed using selected phenotypic criteria and conf i rmed using the Vitek 2 automated system. This system was used to determine the susceptibilities of 21 antimicrobial agents. Patients， isolates and drug data were analyzed using the SPSS statistical software package to determine some epidemiological and microbiological patterns. Results: Of the 105 stains， A. baumannii accounted for 49 （46.67%）， A. baumannii complex， 19 （18.09%），A. baumannii/haemolyticus 32 （30.47）， Acinetobacter haemolyticus 4 （3.81%）， Acinetobater lwoffii 1 （0.95%） and unidentified Acinetobater species 2 （1.3%）. Of the 105 Acinetobacter strains，103 （98.1%） were found multidrug resistant （MDR）. A. baumannii strain were 100% sensitive to colistin and 74.5% to trimethoprim + sulfamethoxazole. The remaining 19 antimicrobial agents revealed low or no sensitivities: amikacin 16.3%； ampicillin 7.7%； ceftazidime 7.3%. Distribution of similar sensitivities was shown by other Acinetobacter species. Mean number of isolates from males and females indicates no statistical variation （P=0.867） whereas age groups showed signif i cant dif f erences （P= 0.008） as it is clear from the high percentage of infected individuals more than 60 years followed by those aged 20 to 29 years old （19.05%）. Upper respiratory tract （30.48%）， lower respiratory tract （47.65%） and subcutaneous tissue（9.5%） were the main sources of Acinetobacter spp. but mean numbers of isolates from these specimens indicate no discrepancy between specimens （P= 0.731）. Conclusions: Acinetobacter species including A. baumannii were found MDR （98.1%） according to the current Acinetobacter spp. antimicrobial categorization. Approximately half of these strains were A. baumannii. All Acinetobacter species were 100% sensitive to colistin and to some extent to trimethoprim + sulfamethoxazole （74.5%）. ICU-acquired pneumonia among patients over 60 years of age who spend prolong times at artif i cial ventilations made up the majority of the cases.

1. Introduction

Acinetobacter species especially Acinetobacter baumannii （A. baumannii） are emerging as a serious cause of health care-associatedinfections especially in intensive care units （ICU）. The rising numbers of multi-drug resistant （MDR） Acinetobacter species has limited the therapeutic choices for infections control ［1］. Infections in crucially sick cancer patients have augmented mortality and added to the ICU stay ［2］.

Acinetobacter associated infections represent a tough challenge to control in seriously sick patients especially those in ICU. Acinetobacter species have the capacity to acquire resistance to almost all presently existing antimicrobial agents ［3］. Also，ICU admission and hospitalization of patients infected by A. baumannii increases the risk of ventilator-associated pneumonia［4］. A. baumannii was found the most common and increasingly important pathogen associated with ventilator-associated pneumonia particularly the late-onset and recurrent ventilator-associated pneumonia in a tertiary care hospital in Riyadh， Saudi Arabia ［5］. A retrospective study conducted between 2005 to December 2010 in Riyadh region indicated that there was a signif i cant increase in antimicrobial resistance A. baumannii ［6］.

A. baumannii is ubiquitous which may be found in food， water and soils as well as on the skin of healthy human. Strains of A. baumannii endure adverse environmental condition such as dryness for long time ［7］. Such characteristics help A. baumannii to spread easily by all potential routes. Clinical health workers in all hospital sections stated the danger of A. baumannii but the problems is much worse in internal medicine or ICU. Variations in recording A. baumannii among wards could be a result of selective pressure induced on organisms generated by the random unsupervised use of broadspectrum antibiotics ［8］.

In recent years， A. baumannii showed a radical decrease in susceptibility to carbapenems. The main carbapenem resistance mechanism was found due to class D-OXA-type enzymes （oxa-23 and oxa-24/40） with carbapenemase activity. The authors concluded this is a key epidemiological worry as medicinal choices turn out to be narrow. Doctors will rely on polymyxin in combinations with other antibiotics ［9］. Recent study reported the appearance of ST236 in Saudi Arabia and Egypt， and the spread of carbapenem resistant A. baumannii clones belonging to ST884， ST945 and ST1096 in Saudi Arabia ［10］.

Our current understanding of the Acinetobacter associated illness as emerging problem is lacking. Prevalence， risk factors and antimicrobial sensitivity patterns in Saudi Arabia and Aseer region in particular are still need to be determined. One study which was conducted during 2011/2012 at Aseer Central Hospital indicated that all isolates were sensitive to imipramine， meropenem and colistin and showed high resistant to nitrofurantoin and cefoxitin but least resistant to mipenem and ticarcillin. These authors express worry on the rising resistant to antibiotics ［11］. The purpose of the work was to establish the magnitude of A. baumannii associated with infections in Aseer region and their antimicrobial prof i le in the southern Saudi Arabia. Publishing such information will establish database and will assist authorities to establish policies towards controlling the infections.

This study aimed to identify and to determine the antimicrobial susceptibility of A. baumannii clinical isolates from ICU at Aseer Central Hospital.

2. Materials and methods

2.1. Ethical approval

The present research was approved by the College of Medicine Ethical Committee. Individual consent from each patient was overlooked by the committee because of the retrospective nature of the study.

2.2. Study design and subjects

In this observational study， adult patients （n=105） were admitted to the intensive care unit （ICU）， Aseer Central Hospital during 2014 and 2015 and were retrospectively evaluated.

2.3. Bacterial isolates

Acinetobacter species were isolated from 105 ICU hospitalized infected patients over a 13 month period， Feb. 2014 to Feb. 2015. Isolates were identified using selected phenotypic criteria and confirmed using the Vitek 2 automated system. Samples were processed for culture by standard conventional methods and ppreliminary identification was performed by gram staining，culturing on MacConkey's agar. Non-lactose fermenting bacteria were sub-cultured and incubated for additional overnights. Genus Acinetobacter was identified by Gram staining， cell and colony morphology， positive catalase test， negative oxidase test and absence of motility ［7］.

2.4. Antibiotic sensitivity

Identified species were tested （in vitro） against 21 antibacterial drugs using the Vitek 2 automated system. Antibiotics and their strength used were according to the Clinical and Laboratory Standards Institute guidelines ［7］. The tested antimicrobial agents were: Amikacin， Ampicillin， Aztreonam， Cefepime， Cefotaxime，Ceftazidime， Ciprofloxacin， Colisitin， Fosfomycin， Gentamicn，Imepenem， Levofloxacin， Meropenem， Mezlocillin， Moxifloxacin，Piperacillin， Rifampicin， Tetracycline， Topramycin， Trimethoprim and Trimethoprim + Sulfamethoxazole.

2.5. Statistical analysis

Data were examined using SPSS software version16.0. Univariate analysis of variance was used to compare variation among means of dif f erent variables. P value ＜ 0.05 was considered as the level of signif i cance.

3. Results

3.1. Identification of Acinetobater species

Of the 105 stains， A. baumannii accounted for 49 （46.67%），A. baumannii complex， 19 （18.09%）， Acinetobacter baumannii/ haemolyticus 32 （30.47%）， Acinetobacter haemolyticus 4 （3.81%），Acinetobater lwoffii 1 （0.95%） and unidentif i ed Acinetobater species 2（1.3%） （Figure 1）.

Figure 1. Identities of Acinetobacter species recovered from 105 patients at the ICU， Aseer Central Hospital （2014-2015）.

3.2. Antimicrobial assays

Sensitivity and resistance results of Acinetobacter species to the 21 antimicrobial agents is shown in Table 1. Of the 105 Acinetobacter strains， 103 （98.1%） were found MDR since all MDR were resistant to more than two antimicrobial classes （Table 1）. Results indicated that A. baumannii strains were sensitive to colistin and 74.5% to trimethoprim + sulfamethoxazole. The remaining 19 antimicrobial agents revealed low or no sensitivities: amikacin 16.3%； ampicillin 7.7% and ceftazidime， 7.3%. Similar sensitivities were shown by other Acinetobacter species.

Resistance pattern of Acinetobacter species recovered from 105 patients at the ICU， Aseer Central Hospital （2014-2015） is shown in Table 1. Note all species show high sensitivities to colistin and to some extent to trimethoprim + sulfamethoxazole.

3.3. Distribution of Acinetobacter species according to sex and age group

The majority of the patients were males （63.81%） compared to females （36.19%） （P=0.867）. Age group more than 60 years was the major af f ected groups in the ICU with Acinetobacter spp. （47.62%）followed by those aged 20 to 29 years old （19.05%）. These two groups vary signif i cantly than other age groups （P= 0.008） （Figure 2）.

Figure 2. Distribution of Acinetobacter species according to sex and age among 105 patients attended the ICU， Aseer Central Hospital （2014-2015）.

3.4. Distribution of Acinetobacter species according to specimen type

Upper respiratory tract （30.48%）， lower respiratory tract （47.65%）and subcutaneous tissue （9.50%） were the main sources of Acinetobacter spp. （Figure 3）.

Table 1Sensitivity and resistance results of Acinetobacter species of 21 various antimicrobial agents ［n（%）］.

Fgure 3. Numbers of Acinetobacter species according specimens types and sex of 105 patients attended the ICU， Aseer Central Hospital （2014-2015）.

4. Discussion

The growing numbers of multi-drug resistant （MDR） Acinetobacter species has reduced the medicinal selections for managing Acinetobacter infections. Acinetobacter species including the leading species， A. baumannii， are developing as real infectious threat mainly in intensive care units （ICU）. This study aimed to identify and to establish the antimicrobial profile of A. baumannii isolates from ICU at Aseer Central Hospital. Hospital units have been the focus of repeated concerns regarding the rising number of nosocomial infections.

A. baumannii， a gram-negative， non-fermentative and a noted opportunistic nosocomial pathogenic bacterium which is able of live for long time in varied environmental conditions including hospital environment and human body surface ［12］. It causes dif f erent nosocomial infections particularly nosocomial pneumonia， blood infection， urinary tract infection， surgical wound infection， especially in patients in ICU ［13］. Our present findings do not differ from the global data. We noticed the respiratory specimens （upper and lower） from which we have isolated Acinetobacter species comprised 80.95% of all specimens.

Antibiotic policies and infection control measures are considered of immense value in fi ghting the mounting trends of nosocomial incidents. Genuine ef f orts are needed to develop new antimicrobial agents against these pathogens and to monitor the effi cacy of the presently accessible drugs. For instance， hand hygiene has been found to have impact in controlling infection in Aseer Central Hospital ［14］. Infections due to drug-resistant Gram-negative rods are an emerging risk factor for increased mortality in ICU. A number of studies have indicated the rising trends of pathogens from other body systems and hospital wards ［15， 16］.

Numerous def i nitions have been introduced in medical literature to describe distinctive patterns of resistance among pathogen encountered in healthcare settings. Multidrug-resistant （MDR），extensively-drug resistant （XDR） and pandrug-resistant （PDR）bacteria are now in use in the medical literature. In this regard MDR in Acinetobacter spp. is def i ned as strain which is found nonsusceptible to ≤1 agent in ≤3 antimicrobial structural categories［17］. MDR A. baumannii is recognized globally as an emerging signif i cant health care risk. This bacterium is normally resistant to allβ-lactams and fl uoroquinolones and has to be treated with colistin， amikacin，or tigecycline ［18］.

According to the Acinetobacter spp. antimicrobial categories and agents used to def i ne MDR， XDR and PDR ［17］， the number of MDR identified in this paper is large （98.1%）. One of the most serious and common risks of infections in ICU is the use of medical devices and procedures. ICU-acquired pneumonia （ventilator-associated pneumonia） represents a chief cause of morbidity and mortality in patients in the ICU worldwide ［19］. Our fi ndings go in line with this fact， we have isolated Acinetobacter spp. from more than 80% of the specimens of the ICU patient. Among those the mostly af f ected with signif i cant ratio （P＜ 0.05） were those aged above 60 years （Figure 2）. But gender was not signif i cant is this distribution. This age with such risk may be because of the prolong stay under ventilation.

A. calcoaceticus baumannii complex which had been isolated from patients at Aseer region ［11］ have shown 100% sensitivity to imipramine， meropenem and colistin. Contrary to the present fi nding，all our A. baumannii isolates （n = 49） were found 100% resistant to meropenem （Table 1） but as expected colistin sensitivity is in full agreement with the previous work ［11］. A. baumannii was found to have reduced susceptibility to carbapenems at the at Security Forces Hospital in Saudi Arabia ［9］. Studies unveiled that A. baumannii had the uppermost rate of resistance to carbapenem and sulbactam ［20，21］. Two predominant genotypes related to European clone II were found among isolates of A. baumannii contained bla （OXA-23）， and bla （OXA-24/40） ［20］.

Rising levels of carbapenem-resistant Acinetobacter spp. are noticed in many countries. Warning of infections due to carbapenem-resistant Acinetobacter spp. is required especially when patients are relocated between hospitals. This will help efforts to control the spread of carbapenem resistance ［21］. The synergistic effect of sulbactam/ tazobactam in combination with either meropenem or colistin to combat MDR A. baumannii isolates has been implemented［22］. Colistin and meropenem combination was also used to control extensively drug-resistant and pandrug-resistant A. baumannii isolates ［23， 24］. The use of colistin in addition to vancomycin as a medicinal choice against MDR A. baumannii infections particularly in pediatric wards has been recommended ［25］.

The main limitation of this study is that it no molecular analysis was done to trace the mode of transmission and identify any outbreak linkage. Also， the sample size may be considered comparatively small. This may result in a lack of authority to determine the present of XDR or any other phenomena related to the epidemiology of Acinetobacter spp. in ICU and the hospital at large.

The present study concluded that all Acinetobacter spp. were MDR. Virtually half of these strains were A. baumannii. These were found 100% sensitive to colistin and to some extent to trimethoprim + sulfamethoxazole （74.5%）. A. baumannii complex and A. baumannii/ haemolyticus accounted for a substantial ratio （48.6%）with sensitivities to the tested antimicrobials similar to those given by members of the A. baumannii. Respiratory specimens in ICU represented a source for the majority of the Acinetobacter spp. as it indicated ICU-acquired pneumonias. This predominates amongpatients over 60 years of age who spend prolong times at artif i cial ventilation made up the majority of the cases.

Acknowledgements

The authors thank the administration of Aseer Central Hospital particularly the Head of Laboratories and College of Medicine， King Khalid University for facilitating the completion of this project.

Conflict of interest statement

We declare that we have no conf l ict of interest.

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10.1016/j.apjtm.2016.07.016

Ali Al Bshabshe， Department of Medicine， College of Medicine， King Khalid University， Abha， Kingdom of Saudi Arabia.

Tel: 00966504740409

E-mail: albshabshe@yahoo.com

*Corresponding author: Mohamed E. Hamid， Department of Microbiology， College of Medicine， King Khalid University， Abha， Kingdom of Saudi Arabia.

E-mail: mehamid2@yahoo.com

ICU

Antimicrobials

Aseer Central Hospital