Identification of population of bacteria from culture negative surgical site infection patients using molecular tool

BACKGROUND

Managing surgical site infections, with negative culture report in routine diagnosis is a common dilemma in microbiology accounting more than 30% worldwide. The present study attempted to identify the presence of bacterial spp. if any in wound aspirates/swabs of culture negative surgical site infections of hospitalised patients using molecular tools.

METHODS

Ninety-seven patients with post-operative SSI whose wound swabs/aspirate were negative in the conventional aerobic culture after 72 h of incubation were analysed by 16S rRNA gene specific broad range PCR. The amplified DNA fragments were sequenced by Sanger DNA sequencing method and homology of the sequence were matched using NCBI BLAST (NCBI, USA) RESULTS: Of the 97 patients, 16S rRNA based broad range PCR assay could identify the presence of bacterial pathogen in 53(54.63%) cases, of which 29 isolates were supposed to be of viable but non-culturable bacteria (VBNC), 07 were of obligatory anaerobes and 13 were of unculturable bacteria, 04 were with poly bacterial infections.

CONCLUSIONS

Our study highlights the usefulness of PCR assay in detecting the presence of any VBNC, anaerobes and unculturable bacteria in SSI patients regardless of how well the bacteria may or may not grow in culture. Measures should be taken to use anaerobic culture system and PCR diagnosis along with conventional culture to detect the VBNC and unculturable bacteria where Gram stain is positive for better patient care.

Etiology of childhood diarrhoea among under five children and molecular analysis of antibiotic resistance in isolated enteric bacterial pathogens from a tertiary care hospital, Eastern Odisha, India

Background

Although, India has made steady progress in reducing deaths in children younger than 5 years, the proportional mortality accounted by diarrhoeal diseases still remains high. The present hospital based cross sectional study was carried out to understand the prevalence of various bacterial pathogens associated with the diarrhoea cases in under 5 years age group.

Methods

During, 1st September, 2015 to 30th November 2017, all the childhood diarrhoea cases (≤5 yrs) of SCB Medical College in Odisha, India were included in the study. Stool samples were collected and processed for the isolation of causative bacterial pathogen and the isolated bacterial pathogens were subjected to antibiotic sensitivity testing, molecular analysis of drug resistance. Clinical and demographic data were collected and analyzed.

Results

Three hundred twenty patients were enrolled in the study during the study period from whom 82 bacterial isolates were obtained indicating a proportional causality of 25.6% for bacterial diarrhoea among children in this region. Entero toxigenic E.coli (ETEC) accounted for majority of the cases and and more than 50% of the strains were found to be multi-drug resistant (resistant to more than 3 class of antibiotics). More than 50% of the strains were resistant to current choice of treatment like ciprofloxacin, ofloxacin and ceftriaxone and 2.4% being resistant to Imipenem. ESBL production was also observed in some of the strains and one isolate harboured the NDM-1 gene. Fluoroquinolone resistance was found to be linked with multiple mutations in the QRDR region followed by PMQR determinants.

Conclusion

The current study, to the best of our knowledge is first of its kind which demonstrated the etiology of bacterial diarrhoea in children less than 5 years old and identified diarrheogenic E. coli as the predominant enteropathogen in Odisha. Majority of the isolates being multi-drug resistance calls for a continuous surveillance system in the region which will be helpfulin identifying emerging resistance pattern and for developing suitable intervention stategies.

Genetic diversity of Indian Plasmodium vivax isolates based on the analysis of PvMSP3β polymorphic marker

Background

Malaria is one of the major communicable diseases in India and worldwide. PvMSP3β is a highly polymorphic gene due to its large insertions and deletions in the central alanine-rich region, which, in turn, makes it a valuable marker for population genetic analysis. Very few studies are available from India about the genetic diversity of Plasmodium vivax based on PvMSP3β gene, and hence, this study was designed to understand the molecular diversity of the P. vivax malaria parasite. The accumulating epidemiological data provide insights into the circulating genetic variants of P. vivax in India, and ultimately benefits the vaccine development.

Materials and Methods

A total of 268 samples confirmed to be positive by microscopy, rapid diagnostic test, and quantitative buffy coat test were collected from four different regions of India (Puducherry, Mangaluru, Jodhpur, and Cuttack) in the present study. Polymerase chain reaction (PCR)-based diagnosis was carried out to confirm the P. vivax monoinfection, and only the mono-infected samples were subjected to PvMSP3β gene amplification and further restriction fragment length polymorphism (RFLP) to determine suballeles.

Results

Based on the size of the amplified fragment, the PvMSP3β gene was apportioned into two major types, namely Type A genotype (1.6-2 Kb) was predominantly present in 148 isolates and Type B (1-1.5 Kb) was observed in 110 isolates. The percentage of mixed infections by PCR was 3.73%. All the PCR products were subjected to RFLP to categorize into suballeles and we detected 39 suballeles (A1-A39) in Type A, and 23 suballeles (B1-B23) in Type B genotype. A high degree of diversity was observed among the isolates collected from Mangaluru region when compared to isolates collected from other regions.

Conclusion

The present study showed a high degree of genetic diversity of PvMSP3β gene among the isolates collected from various parts of India. High polymorphism in PvMSP3β gene makes it a promising marker for epidemiological and vaccine development studies.

High Prevalence of Biofilm-Forming MRSA in the Conjunctival Flora in Chronic Dacryocystitis

OBJECTIVES

To report the microbiological spectrum of conjunctival flora and prevalence of biofilm-forming Methicillin-resistant Staphylococcus aureus (MRSA) in conjunctival flora in chronic dacryocystitis.

DESIGN

Prospective, case-control study.

METHODS

We included patients with unilateral chronic dacryocystitis, and their unaffected eyes as control. Microbiological profile and antibiotic susceptibility of the isolates was determined by standard microbiological procedures. S. aureus isolates were further evaluated for Methicillin resistance by Oxacillin resistance screening agar method and mecA polymerase chain reaction (PCR) and for biofilm synthesis by Congo red agar method, Microtitre plate (MTP) assay, and ica A and ica D PCR.

RESULTS

We found 95 patients with unilateral chronic dacryocystitis. Aerobic Gram-positive isolates (74.2%, n = 72) were more than Gram-negative (25.7%, n = 25) or anaerobic isolates (20.5%, n = 25). S. aureus was most common (46.4%, n = 45), followed by Pseudomonas aeruginosa (10.3%, n = 10). Gram-positive isolates showed highest sensitivity to Linezolid (100%) and higher generation fluoroquinolones. Gram-negative isolates showed good sensitivity (>90%) to all tested antibiotics. S. aureus isolates showed MRSA prevalence as 93.5% and 96.9% by Oxacillin resistance screening agar method and mecA PCR, respectively. Biofilm formation was found in 71.8% MRSA isolates by MTP assay and 58.1% MRSA isolates were resistant to ≥3 classes of antibiotics.

CONCLUSIONS

Gram-positive organisms, specifically S. aureus, are the major etiological agent in chronic dacryocystitis. There is high prevalence of MRSA in these isolates and concurrent biofilm formation.

Detection of inducible and constitutive clindamycin resistance among Staphylococcus aureus isolates in a tertiary care hospital, Eastern India

Introduction:

Clindamycin is an excellent drug for skin and soft tissue Staphylococcus aureus infections, but resistance mediated by inducible macrolide-lincosamide-streptogramin B (iMLS_B) phenotype leads to in vivo therapeutic failure even though they may be in vitro susceptible in Kirby–Bauer disk diffusion method.

Objective:

The study was aimed to detect the prevalence of iMLS_B phenotype among S. aureus isolates by double disk approximation test (D-test) in a tertiary care hospital, Eastern India.

Materials and Methods:

A total of 209 consecutive S. aureus isolates were identified by conventional methods and subjected to antimicrobial susceptibility testing by Kirby–Bauer disk diffusion method. Erythromycin-resistant isolates were tested for D-test.

Results:

From 1282 clinical specimens, 209 nonrepeated S. aureus isolates were obtained. Majority of isolates 129 (61.7%) were methicillin-resistant S. aureus (MRSA). There was statistically significant difference between outpatients 60.1% and inpatients 39.9% (P < 0.0001). From 209 S. aureus isolates, 46 (22%) were D-test positive (iMLS_B phenotype), 41 (19.6%) were D-test negative (methicillin sensitive [MS] phenotype), and 37 (17.7%) were constitutively resistant (constitutive macrolide-lincosamide-streptogramin B phenotype). The incidence of inducible, constitutive, and MS phenotype was higher in MRSA isolates compared to MS S. aureus (MSSA). The constitutive clindamycin resistance difference between MSSA and MRSA isolates were found to be statistically significant (P = 0.0086).

Conclusion:

The study revealed 22% of S. aureus isolates were inducible clindamycin resistant, which could be easily misidentified as clindamycin susceptible in Kirby–Bauer disk diffusion method. Therefore, clinical microbiology laboratory should routinely perform D-test in all clinically isolated S. aureus to guide clinicians for the appropriate use of clindamycin.

Evaluation of Genotypic and Phenotypic Methods for Detection of Methicillin Resistant Staphylococcus aureus in a Tertiary Care Hospital of Eastern Odisha

INTRODUCTION

Methicillin resistant Staphylococcus aureus has emerged as an important pathogen in nosocomial and community acquired infections. Accurate and rapid identification of MRSA in clinical specimens is essential for timely decision of effective antimicrobial chemotherapy.

AIM

The present study was conducted to compare efficacy of four conventional phenotypic methods, with mec- A based polymerase chain reaction (PCR) for MRSA identification.

MATERIALS AND METHODS

Methicillin resistance was determined in 200 S.aureus isolates by oxacillin disc diffusion, cefoxitin disc diffusion, Oxacillin Resistance Screening Agar and E-test. The results were compared with mec-A based PCR.

RESULTS

Among 200 S.aureus isolates 62 (31%) were positive for mec-A gene by PCR. Cefoxitin disc diffusion, Oxacillin Resistance Screening Agar and E-test showed 100% specificity. Oxacillin disc diffusion had lowest sensitivity (82.5%) and specificity (98.5%) among all. The conventional methods take more time than PCR for diagnosing MRSA. Linezolid, Vancomycin & Dalfopristin were the highly sensitive drugs against MRSA isolates.

CONCLUSION

Cefoxitin disc diffusion, is rapid, simple and cheaper, hence can be used routinely as an alternative to PCR for detection of MRSA in resource constraint laboratories.

Biofilm as a virulence marker in Candida species in Nosocomial blood stream infection and its correlation with antifungal resistance

Nosocomial blood stream infections (BSI) due to fungi especially Candida is increasing steadily. A two year prospective study was conducted in the S.C.B. Medical College with an aim to evaluate the species distribution, antifungal susceptibility and biofilm formation of Candida spp. isolated from nosocomial BSIs. 34 Candida spp. were isolated from 359 blood cultures. Antifungal susceptibility was performed by microbroth dilution technique and both visual and spectrophotometric method were used for biofilm detection. C. tropicalis was the common spp. isolated followed by C. parapsilosis and others. Most (92%) of the isolates were susceptible to Amphoterecin-B and highest resistance was observed against Flucytosine (37%) and Fluconazole(35%). Biofilm production and antifungal resistance was observed more in nonalbicans Candida spp.

Study of biofilm in bacteria from water pipelines

CONTEXT

A biofilm is a layer of microorganisms contained in a matrix (slime layer), which forms on surfaces in contact with water. Their presence in drinking water pipe networks can be responsible for a wide range of water quality and operational problems.

AIM

To identify the bacterial isolates, obtained from water pipelines of kitchens, to evaluate the water quality & to study the biofilm producing capacity of the bacterial isolates from various sources.

SETTINGS AND DESIGN

A prospective study using water samples from aqua guard & pipelines to kitchens of S.C.B Medical College hostels.

MATERIALS AND METHODS

Standard biochemical procedures for bacterial identification, multiple tube culture & MPN count to evaluate water quality & tissue culture plate (TCP) method for biofilm detection was followed.

STATISTICAL ANALYSIS

STATA software version 9.2 from STATA Corporation, College station road, 90 Houston, Texas was used for statistical analysis.

RESULTS

One hundred eighty seven isolates were obtained from 45 water samples cultured. The isolates were Acinetobacter spp. (44), Pseudomonas spp.(41), Klebsiella spp.(36) & others . Biofilm was detected in (37) 19.78 % of the isolates (95% CI 30.08% -43.92%) including Acinetobacter spp.-10, Klebsiella spp. - 9, Pseudomonas spp. - 9, & others, majority (34) of which were from kitchen pipelines.

CONCLUSION

Water from pipeline sources was unsatisfactory for consumption as the MPN counts were > 10. Most of the biofilm producers were gram negative bacilli & Pseudomonas & Acinetobacter spp. were strong (4+) biofilm producers.

NS1 Antigen Capture ELISA an Effective Method for Diagnosis of Early Dengue Infection - Report of an Outbreak at Angul District, Odisha, India

BACKGROUND

An outbreak of dengue infection occurred in Angul district of Odisha in the month of August & September, 2011. The study was undertaken to detect NS1 antigen positivity among the study population, to compare IgM capture ELISA with NS1 antigen detection for diagnosis of dengue and to identify the predominant genotype of Dengue virus responsible for the outbreak.

MATERIALS AND METHODS

Total 1020 serum samples were collected from clinically suspected cases of dengue from the outbreak. All were subjected for NS1 antigen detection, 92 were selected based on their clinical severity of illness (fever, rash, bleeding manifestation, arthralgia) for further study of IgM ELISA and platelet count and 148 NS1 positive samples were selected from different Blocks of Anugul district for RT-PCR at NIV, Pune, India.

RESULTS

Five hundred and thirteen (50.2%) samples were positive for NS1 antigen (highly significant p-value <0.0001, C.I - 95%) with 88% positivity during 1-5 days. The NS1 Ag positivity was peaked to 86.9% on days 3 to 5 (Sensitivity & NPV - 100% each) & declined to 6.2% during 6-10 days with a low sensitivity of 7.14% but 100% specificity & PPV. However, the IgM antibody positivity was 81.2% on days 6 to 10 and 87.5% after 10 days (Sensitivity- 100%, Specificity-13.33%,PPV-7.14% & NPV - 100%). RT-PCR resulted 32.4% positivity (6- DEN1, 39 - DEN 2 & 3- DEN 3) among which 20% were in IgM +ve & 68% in IgM -ve cases.

CONCLUSION

Therefore, early diagnosis of dengue could be mainly by NS1 antigen detection whereas Ig M ELISA is a better tool during the later stage of infection &RT-PCR is more effective in IgM -ve cases.The predominant genotype responsible for the outbreak was found to be DEN-2.

Coexistence of cutaneous tuberculosis (scrofuloderma) and hanseniasis-a rare presentation

Cutaneous tuberculosis, pulmonary tuberculosis and hanseniasis are all caused by different spp. of Mycobacterium, an intracellular pathogen whose development depends on impaired cell mediated immunity. Scrofuloderma is the most common variant of cutaneous tuberculosis, which is characterized by a direct extension of the skin which overlies the infected lymph gland, bone or joint, that breaks down to form an undermined ulcer. We are reporting a rare association of Scrofuloderma (cutaneous tuberculosis) with Hanseniasis (leprosy) in an adult male whose immune status was controversial.

Intraocular Gnathostoma spinigerum: a case report

Live intraocular nematode is a rare occurrence that is mostly reported in South East Asian countries. Herewith we report such a case from Nayagarh district of Odisha. A 28 year old female presented with swelling, redness, lacrimation, pain & diminished vision of left eye since 2 1/2 years. Slit lamp examination revealed a worm piercing iris muscle. The worm was removed by paracentesis of anterior chamber and sent to the Department of Microbiology. It was identified to be Gnathostoma spinigerum basing on the typical morphology of its cephalic end. The patient responded completely to oral albendazole therapy.

Role of azithromycin against clinical isolates of family enterobacteriaceae: A comparison of its minimum inhibitory concentration by three different methods

PURPOSE

To determine the effect of azithromycin, a new azalide antibiotic, on clinical isolates of the family Enterobacteriaceae and to determine and compare its minimum inhibitory concentration (MIC) by disk diffusion, agar dilution and E-test methods.

MATERIALS AND METHODS

One hundred fifty-nine bacterial strains belonging to the family Enterobacteriaceae, isolated from different clinical samples, were tested for their susceptibility to azithromycin by disk diffusion, agar dilution and E-test methods. The MIC values were analysed and the percentages of agreement between the different methods were mentioned.

RESULTS

Of the 159 isolates of the family Enterobacteriaceae, 60.37% were E. coli followed by Klebsiella species 28.3%, Salmonella and Shigella species 3.77% and Enterobacter and Citrobacter species 1.88% each. Maximum isolates were obtained from urine 117/159 (73.58%). Azithromycin was found to be more active against Salmonella and Shigella species, showing 100% sensitivity the by E-test and 83.33% by the disk diffusion methods. In the agar dilution method, 83.33% of Salmonella and 66.66% of Shigella species were sensitive to azithromycin. The overall agreement between disk diffusion and agar dilution method was 96.8%, between agar dilution and E-test was 88% and between disk diffusion and E-test was 91.2%.

CONCLUSION

Azithromycin may become an important addition to our antimicrobial strategies, especially for the treatment of bacterial diarrhoea and infections caused by Salmonella typhi.

Chromobacterium violaceum: a case report of an unusual bacterium causing puerperal sepsis

Human infections by Chromobacterium violaceum are rare. Till date 6 cases have been reported from southern and eastern parts of India. We report here a case of puerperal sepsis by C. violaceum, probably the first case from Eastern part of Orissa. The patient was successfully treated with amikacin and gatifloxacin.

Bacteremia due to Rhodococcus equi--a case report

Rhodococcus equi (R. equi) primarily causes zoonotic infections affecting grazing animals and is an unusual cause of infection in immunocompetent human beings. We report a case of bacteremia due to R. equi a rare isolate in a child suffering from protein energy malnutrition

Comparison of parasite lactate dehydrogenase based immunochromatographic antigen detection assay (optimal) with microscopy for detection of malaria parasites

This study was done to compare the ability of a newly developed rapid malaria test OPtiMAL, an immunochromatographic antigen detection assay for the diagnosis of malaria using parasite lactate dehydrogenase, against standard microscopy. Blood samples were obtained from 232 patients suspected of having malaria. A total of 122 samples (52.5%) were positive by blood films while 118 (50.8%) were positive by OPtiMAL test. The blood film indicated that 21.4% (26 of 122) of the patients were positive for P. falciparum and 78.6% (96 of 122) were infected with P. vivax. OPtiMAL test showed that 21.2% (25 of 118) were positive for P. falciparum and 78.8% (93 of 118) were infected with P. vivax. This assay had sensitivities of 88.4% and 96.8% compared to traditional blood films for detection of P. falciparum and P. vivax malaria respectively. Thus OPtiMAL test can be used with or without traditional blood film examination for detection of both P. vivax and P. falciparum malaria and can be effectively used for the rapid diagnosis of malaria.

Seroprevalence of anti HCV antibody in and around Cuttack, Orissa

One hundred ninety (190) serum samples and 52 control samples consisting of high risk individuals were screened for anti HCV antibody by 3rd generation ELISA test. The prevalence rate was found to be 1.57% in total but it was 2.12% in healthy voluntary blood donors. All were males between the age group of 21 to 40 years. All the control samples were found to be seronegative for anti HCV ab.