Ali: A study on the bacterial isolates from blood cultures of a tertiary care hospital


Introduction

Blood stream infections (BSI) are the most important and common cause of morbidity and mortality in tertiary care hospitals.1, 2

Clinical signs and symptoms, though useful in diagnosing possible cases of bacteremia have only limited specificity. Definitive diagnosis is only by performing a bacteriologic culture and antimicrobial susceptibility testing of the blood samples to identify the pathogens. Since the results are usually not available promptly a knowledge of epidemiologic and antimicrobial susceptibility pattern of blood pathogens is life saving and very useful for early treatment of critically ill patients with blood stream infections.3, 4, 5

Antibiotic resistance is a major limiting factor in the selection of antibiotics in the treatment of blood stream infections.6, 7 Both gram positive and gram negative bacteria are associated with bacteremia but, most of the Gram-negative bacteria were found to be multi drug resistant with a very high resistance to beta-lactam antibiotics.3

This is the first study conducted in our Department of Microbiology to describe the epidemiological, bacterial profile and antimicrobial resistance pattern of pathogens in bloodstream infections.

Materials and Methods

Our study is a prospective cross-sectional study carried out in the Department of Microbiology, Govt. Thiruvarur Medical College Hospital, Tamil Nadu. This study was conducted over a period of six months from December 2020 to May 2021. Blood samples were collected under aseptic conditions and cultured by aerobic culture method. Identification of bacterial isolates were done using standard bacteriologic and biochemical testing methods and antibiotic sensitivity detection done by Kirby- Bauer disc diffusion method and results were interpreted by following Central Laboratory Standards Institute (CLSI) guidelines, using Hi-Media discs, Mumbai.8

Results

Seven hundred and eight blood samples from febrile patients from various wards in the hospital were collected. Positive bacterial growth was observed in 201 isolates showing a blood culture positivity of 28.3%.

Patient characteristics

Sex wise distribution shows 94(46.7%) samples were from males and 107(53.3%) samples were from females and age wise distribution showed 84(41.8%) samples from neonates, 24(11.9%) samples from less than 5 yrs, 11(5.5%) samples from 5-15 yrs and 82(40.8%) samples from above 15 yrs of age out of the 201 positive blood cultures. [Table 1]. The majority of cases were from NICU 88(43.7%) followed by labour ward 19(9.4%) {Figure 1}.

Etiologic agents of BSI

Of the 201 positive bacterial growth, 115(57.2%) were gram positive cocci predominated by Coagulase negative staphylococci 111(55.2%) followed by Staphylococcus aureus 4(1.9%) and 86(42.8%) were gram negative bacilli predominated by Klebsiella pneumoniae 49(24.4%) followed by Proteus mirabilis 16(8%), Escherichia coli 8 (4%), Proteus vulgaris 5(2.5%), Klebsiella oxytoca 4(2%) and Pseudomonas aeruginosa 4(2%) [Figure 2 &Table 2].

Antimicrobial susceptibility profiles

The antibiotic susceptibility patterns of Gram positive cocci, Enterobacteriaceae and Pseudomonas aeruginosa have been shown in the tables [Table 2, Table 3, Table 4] respectively.

Figure 1

Ward wise distribution of positive blood cultures

https://s3-us-west-2.amazonaws.com/typeset-prod-media-server/d141280f-3d66-44e9-8219-e91cc19beac3image1.png
Figure 2

Bacterial distribution of positive blood cultures

https://s3-us-west-2.amazonaws.com/typeset-prod-media-server/d141280f-3d66-44e9-8219-e91cc19beac3image2.png
Table 1

Showing age wise frequency of bacterial isolates recovered from patients with BSI

Age of the patient

CoNS

Staph. Aureus

Klebsiella pneumoniae

Klebsiella oxytoca

Proteus mirabilis

Proteus vulgaris

Esch erichia coli

Pseudomonas aeruginosa

<28 days

42

1

23

1

7

2

7

1

<5 yrs

15

1

6

0

1

0

0

1

5-15yrs

7

0

1

1

1

0

1

0

>15yrs

47

2

19

2

7

3

0

2

Total

111

4

49

4

16

5

8

4

Table 2

Antimicrobial susceptibility pattern of gram positive bacterial isolates from blood culture.

Antibiotic

CoNS sensitive

CoNS resistant

Staph.aureus sensitive

Staph.aureus resistant

Ampicillin

32 (28.8%)

79 (71.2%)

1 (25%)

3 (75%)

Clindamycin

101(91%)

10 (9%)

4 (100%)

0 (0%)

Cefoxitin

32(28.8%)

79(71.2%)

1 (25%)

3 (75%)

Erythromycin

30 (27%)

81 (73%)

3 (75%)

1 (25%)

Ciprofloxacin

97 (88.2%)

14 (12%)

3 (75%)

1 (25%)

Gentamicin

95 (85.5%)

16 (14.5%)

4 (100%)

0 (0%)

Cotrimoxazole

88 (79)

23 (21)

3 (75%)

1 (25%)

Vancomycin

111(100%)

0 (0%)

3 (75%)

1 (25%)

Linezolid

111(100%)

0 (0%)

4 (100%)

0 (0%)

Table 3

Antimicrobial susceptibility pattern of Enterobacteriaceae from blood culture.

Antibiotic

Klebsiella sensitive

Klebsiella resistant

E.coli sensitive

E.coli resistant

Proteus sensitive

Proteus resistant

Amoxycillin-Clavulanic acid

34 (65.3%)

18 (34.7%)

4 (50%)

4 (50%)

23 (74%)

8 (26%)

Ciprofloxacin

48 (92.3%)

4 (7.7%)

8 (100%)

0 (0%)

30 (97%)

1 (3%)

Gentamicin

49 (94.2%)

3 (5.8%)

7 (87.5%)

1 (12.5%)

30 (97%)

1 (3%)

Cotrimoxazole

41 (79%)

11 (21%)

5 (62.5%)

3 (37.5%)

22 (71%)

9 (29%)

Ceftazidime

21 (40.3%)

31 (59.7%)

2 (25%)

6 (75%)

20 (64.5%)

11 (35.5%)

Ceftriaxone

20 (38.4%)

32 (61.6%)

2 (25%)

6 (75%)

18 (58%)

13 (42%)

Cefotaxime

13 (25%)

39 (75%)

2 (25%)

6 (75%)

19 (61%)

12 (39%)

Meropenem

51 (98%)

1 (2%)

8 (100%)

0 (0%)

31 (100%)

0 (0%)

Table 4

Antimicrobial susceptibility pattern of Non-fermenter from blood culture.

Antibiotic

Pseudomonas sensitive

Pseudomonas resistant

Ceftazidime

0 (0%)

4 (100%)

Amikacin

2 (50%)

2 (50%)

Ciprofloxacin

4 (100%)

0 (0%)

Piperacillin-Tazobactum

0 (0%)

4 (100%)

Meropenem

4 (100%)

0 (0%)

Tobramycin

4 (100%)

0 (0%)

Discussion

Blood stream infections are one of the leading causes of mortality in tertiary care hospitals. A continuous surveillance of the bacteriological profile and antibiotic susceptibility pattern of the blood culture isolates are a best guide to the clinicians for timely and effective management of BSI. Early administration of antibiotics in patient with septicemia drastically increases recovery and decreases mortality rate.9 This study shows the bacteriological profile and antimicrobial susceptibility pattern of the blood culture isolates, aiding the immediate and proper management of septicemic cases. Blood culture positivity of 28.3% was observed in our study which is similar to blood culture positivity rate observed in other studies.10 Sex wise distribution shows and 107(53.3%) samples were from females and 94(46.7%) samples were from males similar to study of Manmeet Kaur et al [2016]3 and age wise distribution showed 84(41.8%) samples were from neonates a scenario found in developing countries like North Ethiopia.10

Gram negative bacteria were found to be the majority over Gram positive bacteria in most of the studies. Coagulase negative staphylococci 111(55.2%) were the predominant bacteria in our study which is in similarity to study by Prakash KP et al [2011].11 Coagulase negative staphylococci, which is the usual skin commensal is being commonly reported as an important bloodstream pathogen for the past 2 decades. Improper blood collection procedure, increased usage of prosthetic heart valves and persistance of long standing i.v. devices are found to be the possible modes of transmission of blood stream infection by Coagulase negative staphylococci.12, 13 Adequate skin antisepsis before collection of blood cultures by peripheral venipuncture reduces blood culture contamination rates and favours correct interpretation of results by the clinician. Tincture of iodine, chlorine peroxide and chlorhexidine gluconate are more efficient than povidine iodine preparations for skin antisepsis.14 Multi drug resistant Klebsiella were the second most pathogen causing BSI in our study.

Antibiotic sensitivity testing showed Vancomycin and Linezolid to be the most effective antibiotic for Gram positive isolates and resistance to Erythromycin and Ampicillin comparable to the findings of Druba Hari et al.[2020].15 In our study 100% of the Staphylococcus aureus isolates and 92.9% of Coliforms were sensitive to Gentamicin similar to a Nigerian study16 on blood cultures of septicaemic children. Meropenem, Gentamicin and Ciprofloxacin were found to be effective for Enterobacteriaceae group of bacteria in accordance to the study by Tomar et al, [2019].17 Non-fermenter Pseudomonas was highly sensitive to Meropenem, Ciprofloxacin and Tobramycin similar to findings Tomar et al, [2019].17

Conclusion

This study has shown that Coagulase negative staphylococci and multidrug resistant Klebsiella are the leading causes of blood stream infections in Tiruvarur. Antibiotic resistance pattern of these agents to common antibiotics alerts us to implement rational use of antibiotics. Continuous epidemiological research such as the current one is always vital to guide clinical practice, prevent antimicrobial resistance and to make policies on rational use of anti-microbial agents.

Author's Contributions

All the authors were actively involved in the laboratory testing and preparation of the final manuscript.

Acknowledgements

We sincerely thank the laboratory personnel of the Department of Microbiology, Govt. Thiruvarur Medical College.

Conflict of Interest

The authors declare that there are no conflicts of interest in this paper.

Source of Funding

None

References

1 

BA Forbes DF Sahm AS Weissfeld Bailey and Scott’s Diagnostic microbiology: A textbook for isolation and identification of pathogenic microorganisms11th Edn.St. Louis: The Mosby Company2002378422

2 

LS Young GL Mandell JE Bennet R Dolin Sepsis syndromePrinciple and practice of Infectious DiseasesElsevier: Churchill Livingstone1995690705

3 

MK Gill S Sharma Bacteriological profile and antibiotic resistance pattern in blood stream infection in critical care units of a tertiary care hospital in North IndiaIndian J Microbiol Res2016332704

4 

A Kumar D Roberts K E Wood A Kumar S Symeoneides L Taiberg Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shockCrit Care Med200634615899610.1097/01.CCM.0000217961.75225.E9

5 

SS Huang BJ Labus MC Samuel DT Wan AL Reingold Antibiotic resistance patterns of bacterial isolates from blood in San Fransisco County, CaliforniaEmerg Infect Dis199682195201

6 

HS Sader RN Jones S Andrade-Baiocchi DJ Biedenbach Four-year evaluation of frequency of occurrence and antimicrobial susceptibility patterns of bacteria from bloodstream infections in Latin American medical centersDiagn Microbiol Infect Dis20024432738010.1016/S0732-8893(02)00469-87

7 

M Kato-Maeda A Bautista-Alavez A L Rolon-Montesdeoca Increasing trend of antimicrobial drug-resistance in organisms causing bacteremia at a tertiary-care hospital: 1995 toRev Invest Clin20005566005

8 

Clinical and Laboratory Standards Institute (CLSI). Performance standards for antimicrobial susceptibility testing; twenty-fourth informational supplement, CLSI document M100-S24. Wayne and Pennsylvania2014

9 

K Cruickshank J P Duguid B P Marmion Test for sensitivity to microbial agentMedical MicrobiologyChuchill Livingstone1980190209

10 

AG Wasihun LN Wlekidan SA Gebremariam TA Dejene AL Welderufael TD Haile Bacteriological profile and antimicrobial susceptibility patterns of blood culture isolates among febrile patients in Mekelle Hospital, Northern EthiopiaSpringerplus2015431410.1186/s40064-015-1056-x

11 

P Patel V Arora P Geethanjali Bloodstream Bacterial Pathogens and their Antibiotic Resistance Pattern in Dhahira RegionOman. Oman Med J20112642407

12 

NV Rani K Gopal MV Narendra D Vishwakanth VRD Nagesh M Yogitha A retrospective study on blood stream infections and antibiotic susceptibility patterns in a tertiary care teaching hospitalInt J Pharm Sci2012515438

13 

A V Devi B Sahu S Damrolien S Praveen P Lungran M Devi A study on the bacterial profile of bloodstream infections in Rims HospitalJ Dent Med Sci20151411823

14 

ML Wilson JW Wilson EA Vetter Clinical and Laboratory Standards Institute. Principles and procedures for blood cultures: Approved guidelineClinical and Laboratory Standards Institute13Wayne, PA: Clinical and Laboratory Standards Institute2007

15 

DH Chandi P Patil S Damke S Basak A Rangaiahagari Bacteriologic Antibiography Outline of Isolates from Blood Culture at Tertiary CenterJ Pure Appl Microbiol20201442801610.22207/JPAM.14.4.55

16 

MM Meremikwu CE Nwachukwu AE Asuquo JU Okebe SJ Utsalo Bacterial isolates from blood cultures of children with suspected septicaemia in Calabar, NigeriaBMC Infect Dis2005511010.1186/1471-2334-5-110

17 

KM Sangita R Tomar NK Saha Bacteriological Profile and Antibiogram of Blood Culture Isolates From a Tertiary Care HospitalInt J Med Sci Innov Res (IJMSIR)20194618792



jats-html.xsl

© This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


  • Article highlights
  • Article tables
  • Article images

Article History

Received : 15-07-2021

Accepted : 05-08-2021

Available online : 01-09-2021


View Article

PDF File   Full Text Article


Downlaod

PDF File   XML File   ePub File


Digital Object Identifier (DOI)

Article DOI

https://doi.org/10.18231/j.ijmmtd.2021.036


Article Metrics






Article Access statistics

Viewed: 150

PDF Downloaded: 41



Wiki in hindi