Sterile body fluids infections: Profile of bacteria and their antimicrobial resistance pattern in a tertiary care hospital from Uttar Pradesh

INTRODUCTION

The various body cavities are sterile sites and these body cavities are filled with sterile body fluids. The purpose of these body fluids is to bathe the organs and membranes for the protection of vital organs, transportation of nutrients, regulation of body temperature, and reducing friction.^[1,2] The body fluids are generally sterile; however, different types of microorganisms can invade the body cavities leading to infection and physicochemical changes in these body fluids. Early identification of the organisms causing sterile body fluid infection along with antimicrobial susceptibility can help clinicians to initiate early and targeted antimicrobial therapy.^[3] The data on bacterial profile and their antimicrobial susceptibility pattern isolated from sterile body fluids can help to develop a local antibiogram of a particular healthcare setting. The knowledge of commonly isolated organisms from various sterile body fluids along with their antimicrobial susceptibility testing (AST) pattern in the form of antibiogram can help in the selection of appropriate empirical antibiotics.^[4]

The culture positivity rate in sterile body fluid infections is comparatively low varying from 10% to 30%.^[4] Moreover, the patients empirically treated with antibiotics before sample collection hinder the recovery of pathogenic bacteria on culture. However, multidrug-resistant organisms’ (MDROs) emergence is also becoming an important challenge for treating clinicians and there is an urgent need for judicious use of antibiotics which can significantly reduce morbidity, hospital stay, and mortality, ultimately leading to reduced cost of treatment among patients with these infections.^[5]

Rapidly increasing multidrug resistance (MDR) against commonly used antimicrobials is an important public health issue of concern worldwide. The distribution profile of bacteria isolated from sterile body fluids and their drug resistance patterns needs to be collected from various tertiary care institutions located in various regions which can further guide us in the implementation of antimicrobial stewardship program nationally.

Therefore, we planned this study to know the distribution profile of various bacterial isolates implicated in sterile body fluid infections, along with their AST patterns which can help us while selecting appropriate empirical antimicrobial therapy at our institution for better patient care.

MATERIALS AND METHODS

This prospective hospital-based study was done at a tertiary care medical teaching hospital in western Uttar Pradesh, for a period of 2 years. The clinical sterile body fluid specimens from patients were collected following exclusion and inclusion criteria.

RESULTS

During the 2 years of the study period, 1980 sterile body fluid samples collected for culture and AST were processed. The pathogenic bacteria grown in 192 samples and culture positivity rate were found to be 9.7%. The culture positivity rate of various sterile body fluid samples is shown in [Figure 1]. The maximum culture positivity rate of 14.28% was observed in synovial fluid samples.

The culture positivity among males and females was found to be 57.37% and 42.63%, respectively. Age-wise distribution of patients with culture-positive sterile body fluids along with culture positivity rate is shown in [Table 3]. Department-wise distribution of the isolates is depicted in [Figure 2].

The distribution of various pathogenic bacterial isolates isolated from positive sterile body fluids cultures is shown in [Figure 3]. Among all bacterial isolates, GPC was 32 (16.67%) while GNB was 160 (83.33%).

DISCUSSION

Sterile body fluid infections contribute as important and significant causes of serious morbidity and mortality. These infections are among the common healthcare-associated infections (HCAIs). The condition can be life-threatening among patients in critical conditions especially those admitted to intensive care and high-dependency units of the hospitals.

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Figure 1:

Positivity rate of various sterile body fluid samples.

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Figure 2:

Department-wise distribution of isolates.

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Figure 3:

Distribution of all bacterial isolates isolated from sterile body fluids.

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The culture positivity rate of sterile body fluids was found to be 9.69% in our study. Highly variable culture positivity rates were observed in various studies ranging from less than 10% to more than 50%. A higher positivity rate of 30% was observed by Sharma et al. in a study done in 2017 from north India^[7] and 16.70% of positivity rate was reported by Shume et al. in 2022.^[8] Around 15% of the culture positivity rate was reported by Sharma et al. in 2017, Sujatha et al. in 2015, and Vishalakshi et al. in 2016.^[5,9,10] The culture positivity depends on so many factors related to clinicians, sample collection personnel, microbiologists, and factors related to the processing of the samples in the laboratory.

The clinically significant isolates were predominantly isolated from male patients (57.37%) as compared to female patients (42.63%) and the male-female ratio was found to be 1.3:1 in this study. More or less similar findings were observed from various studies in the previous years including studies done by Sharma et al. in 2018 and Teklehymanot et al. in 2017.^[5,11]

Age-wise distribution of patients with culture-positive sterile body fluids revealed the higher culture positivity rate among economically productive age groups such as the age group of 31–40 years, followed by 41–50 years comprising 22.22% and 14.29%, respectively. The predominance in this age group could be due to more activities leading to more exposure to infections.

A higher proportion of the isolates (58%) were grown in the sterile body fluids samples collected from the patients admitted to the intensive care unit (ICU) as compared to other wards as ICU patients are critically ill and associated with various comorbidities and immunocompromised states hence more prone to various HCAIs.

All the patients with sterile body fluid infections were having invasive devices, but the association of invasive devices with these infections could not be commented on as most of the patients were admitted to ICUs and almost all of them were having invasive devices.

In our study, there was a predominance of GNB. We observed 83.34% of GNB as compared to only 16.66% of GPC among pathogens isolated from sterile body fluids. Similarly, many studies reported predominant isolation of GNB over GPC including studies by Sharma et al., Shume et al., Sandhya et al., and Ebrahim et al. documenting 90%, 70.6%, 71%, and 74.6% of GNB in comparison to GPC isolated from sterile body fluid samples, respectively.^[7,8,12,13] In a study by Bourbeau et al., no predominance of either GPCs or GNBs was observed.^[14] In contrast, there are studies showing the predominance of GPC over GNB including studies by Vishalakshi et al., Çetin et al., and Pal et al.^[10,15,16] This variation in the predominance of either group could be due to variation in hospital flora leading to variation among HCAIs, different hospital infection prevention and control measures followed, different sample sizes, and different geographical areas studied.^[17,18]

Among the Gram-negative bacterial isolates, Acinetobacter spp. was found to be most predominant comprising 40%, followed by Klebsiella pneumoniae (25%), Escherichia coli (15%), Pseudomonas spp. (15%), and Citrobacter spp. (5%). Almost similar findings were reported in many studies including a study by Madigubba et al. with Escherichia coli at 40.10%, followed by Acinetobacter spp. 22.60%, Pseudomonas spp. 18.20%, and K. pneumoniae (14.80%).^[19]

Among GPCs, S. aureus was found to be the most frequently isolated GPC comprising 75% of all GPCs.

In this study, 75% of S. aureus isolates were found to be MRSA. The reported data from the previous studies on MRSA show a wide range of variability ranging from 30% to 100% of MRSA.^{[8,10,15,19,20]} The various factors responsible for differences in the proportion of MRSA could be geographical variations, variations in treatments followed, infection control practices and patient related factors.^[4]

In this study, all S. aureus isolates were found susceptible against vancomycin and linezolid which are considered as last resort of antibiotics for the treatment of MRSA. The sensitivity pattern of S. aureus observed against other antibiotics including 50% against gentamicin, ciprofloxacin, tetracycline, clindamycin, and erythromycin each was sensitive, while 25% against chloramphenicol, moxifloxacin, and cotrimoxazole each were sensitive.

Among Gram-negative isolates, isolates 25% were ESBL producers while 62.50% were carbapenemase producers on screening while none of the isolates were resistant against colistin.

Majority of the bacterial isolates were MDROs with higher resistance against beta-lactams including cephalosporins up to third generation, aminoglycosides, and fluoroquinolones. The predominance of MDR organisms isolated from sterile body fluids was also reported in various studies including studies done by Shume et al. in 2022, Ebrahim et al. in 2020, and Tsegay et al. in 2019 documenting 76.4%, 75%, and 90% of isolates as MDROs.^[8,13,21] A low proportion of 30% of isolates as MDR were documented in a study by Shrestha et al. in 2019.^[20] Most of the recent studies reported majority of the pathogenic bacteria implicated in sterile body fluid infections as MDROs and our findings correlate with these recent studies.^[8,13,21,22] Being a tertiary care medical teaching and referral hospital patients are referred after taking treatment at multiple hospitals in the form of antimicrobials, which can be another important reason for higher proportion of MDROs in our hospital.

The variation in the distribution of MDR organisms and their AST patterns could be due to different bacterial strains confined to that particular hospital environment, geographical variations, awareness of patients toward antibiotic usage, easy over the counter availability of antibiotics, difference in antimicrobial prescribing policies, different hospital infection control practices, and indiscriminately using antimicrobials consequently resulting in emergence and transmission of resistance against antimicrobials.^[8] The higher isolation rate of MDR organisms from sterile body fluids as compared to other samples as documented by Li et al. indicates the inclusion of comparative data during the preparation of antibiogram.^[22]

CONCLUSION

From this study, we concluded that the pathogenic bacteria implicated in infections of sterile body fluids are predominantly MDR. There is huge variation in data on distribution of bacterial species isolated from sterile body fluids and their antimicrobial resistance patterns from different geographical locations and healthcare settings. Thus, data from a particular healthcare setting are important for empirical treatment in that healthcare setting.

The increasing trends of MDR and emergence of resistance against high-end antimicrobials are an alarming situation. It is the time for strict implementation of antibiotic stewardship and hospital infection control measures to prevent antimicrobial resistance.