SENSITIVITY OF BIOFILM-PRODUCING BACTERIA FROM NASOGASTRIC TUBES TO ANTIBIOTICS CEFTRIAXONE & CEFOBACTAM

: Biofilms are defined as microbially derived sessile communities characterized by the cells that are irreversibly attached to a substratum. These organisms have been associated with implant associated infectionsThe present study is therefore undertaken 1. To compare the three screening methods used for detection of biofilm formation (Tissue culture plate method, Tube method and Congo red agar method) and 2. To correlate the antibiotic resistance pattern of biofilm producers and non biofilm producers. : A prospective study was carried out in the department of microbiology, on all orthopedic implant associated infections from September 2015 to July 2016 on aspirated pus samples. A total of 120 non repetitive clinical isolates were taken and subjected to biofilm detection. All the bacterial isolates were identified by standard biochemical tests. Antibiotic susceptibility test of bacterial isolates was performed by Kirby Bauer disk diffusion method according to Clinical Laboratory Standard Institute (CLSI) guidelines on Muller Hinton Agar (MHA). A reference strain of Staphylococcus epidermidis ATCC 35984(positive biofilm producer) and Staphylococcus epidermidis ATCC 12228(non biofilm producer) were used as controls. Tissue culture plate method was considered as gold standard as it detected 25% biofilm producers which included 12% weak biofilm producers which was missed by congo red agar (CRA) and tube method (TM). Also, this correlated to methicillin resistant staphylococcus aureus (MRSA), ESBL, amp-c and MDR pattern of antibiogram. : TCP is considered as most reliable screening method for biofilm detection and should be routinely employed to prevent treatment failures as these organisms are intrinsically resistant to many antimicrobials leading to implant associated infections.

Biofilms are groups of microorganism encased in a matrix of extracellular polysaccharide (slime), called polysaccharide intercellular adhesion (PIA). Bacteria commonly involved include , , , and . The present study was performed to identify antibiotic resistance pattern & their ability to form biofilm in gram negative clinical isolates. All clinical samples received in laboratory for microbial culture during study period of 12 months (2017 to 2018) were included in this study Antibiotic susceptibility testing, ESBL & MBL detection was done for clinical isolates. Biofilm productions were determined by Congo red agar method, Christenson’s Test Tube method and Tissue culture plate method. 327 gram negative isolates were detected. Maximum were (32.72%) followed by (28.44%), (16.51%), (16.51%), Citrobacter species (3.97%). Maximum isolates showed resistance to ampicillin (93.27%) followed by amoxiclave (87.46%), ceftazidime (74%). Out of 327 GNB isolates, biofilm produced by 64 (19.57%) isolates by Tissue culture plate (TCP) method, 38(11.62%) by Congo red agar (CRA) method and 23 (7.03%) by Tube method. Maximum biofilm were detected in (24.29%). There is increase prevalence of multidrug resistant& biofilm forming bacteria. The routine monitoring of multidrug resistance pattern & biofilm detection can be recommended in clinical laboratories to guide proper antibiotic treatment.

BACKGROUND:Escherichia coli accounts for 70%–95% of urinary tract infections (UTIs). UTI is a serious health problem with respect to antibiotic resistance and biofilms formation being the prime cause for the antibiotic resistance. Biofilm can restrict the diffusion of substances and binding of antimicrobials. In this context, the present study is aimed to perform in vitro detection of biofilm formation among E. coli strains isolated from urine and to correlate their susceptibility pattern with biofilm formation.MATERIALS AND METHODS:A total of 100 E. coli strains isolated from patients suffering from UTI were included in the study. The identification of E. coli was performed by colony morphology, Gram staining, and standard biochemical tests. The detection of biofilm was carried out by Congo Red Agar (CRA) method, tube method (TM), and tissue culture plate (TCP) method. Antimicrobial sensitivity testing was performed by Kirby–Bauer disc diffusion method on Muller–Hinton agar plate.RESULTS:Of the 100 E. coli strains, 49 (49%) and 51 (51%) were from catheterized and noncatheterized patients, respectively. Biofilm production was positive by CRA, TM, and TCP method were 49 (49%), 55 (55%), and 69 (69%), respectively. Biofilm producers showed maximum resistance to co-trimoxazole (73.9%), gentamicin (94.2%), and imipenem (11.6%) when compared to nonbiofilm producers. Significant association was seen between resistance to antibiotic and biofilm formation with a P = 0.01 (<0.05).CONCLUSION:A greater understanding of biofilm detection in E. coli will help in the development of newer and more effective treatment. The detection of biofilm formation and antibiotic susceptibility pattern helps in choosing the correct antibiotic therapy.

Urinary tract infection is one of the most serious infectious disease in the world , This study aimed to isolate and diagnose the bacteria that cause UTI and then evaluate its ability to form a biofilm. 100 urine samples were collected for a group of patients attending Al-Diwaniyah Teaching Hospital, who were confirmed to have UTI at different ages. The results showed the presence of bacteria. Escherichia coli and proteus spp in all samples(100%), while Staphylococcus aureus was found in 87% of samples , Enterobacter spp was isolated by 67% and Pseudomonas aeruginosa by 65%. Klebsiella pneumonia at 50 % and Staphylococcus epidermidis and Micrococcus spp each with 30%. Regarding the ability of the isolated bacteria to form biofilm, two methods used Congo-red agar and tube method and the results were as follows 64% for E.coli, K pneumonia with 66.6% while S. aureus showed the ability of formation with 41.6% and negative results for the rest by using tube method while Congo-red agar method results were 25% for 50% for E.coli and S. aureus. The study concluded that Congo red agar method is easy to perform and interpret, while the tube method is highly sensitive and specific.

Contact lenses (CLs) wearing has been increased globally during recent decades, which is one of the main risk factors for developing several ocular infections. Resistant CLs bacterial infections are mainly due to the CLs contamination by bacteria producing biofilm. This study was aimed to assessment of antibiotics resistance and biofilm production among bacterial species isolated from contact lenses in Mukalla city, Hadhramout, Yemen. This cross-sectional study was carried out on 298 participants women during a period from October 2022 to January 2023. The CLs swab samples were collected, then inoculated onto culture media and incubated aerobically at 37°C for 24 hrs. The bacterial isolates were identified by conventional bacteriological methods of cultural characteristics, Gram staining and biochemical test. Antibiotics susceptibility testing was performed by disc diffusion method. Bacterial biofilm production on CLs was detected by tube method (TM) and Congo red agar (CRA) method. The prevalence of CLs bacterial infection was 54.4%. Enterobacter spp. 37.1%, followed by Escherichia coli 28.4%, Pseudomonas aeruginosa 11.7%, Klebsiella pneumoniae 6.8% were the most common Gram-negative isolated from CLs. Staphylococcus epidermides 3.7% and other coagulase negative staphylococci (CoNS) 12.3% were the most common species of Gram-positive bacteria isolated from CLs. The CRA method was found to be effective phenotypic screening method for detection of biofilm production of bacterial isolates from CLs. Prevalence of antibiotics resistance and multi-drug resistance (MDR) biofilm producing strains was found. In conclusion, there is a high prevalence of CLs use by females in Mukalla city, Hadhramout especially for cosmetic purposes. CLs infection due to improper care practices leads to eye complications. Increasing awareness is crucial to avoid identified risk factors for ocular infection.

Biofilm is one of the known virulence factors of Candida, an important pathogen and commensal. Early detection of biofilm production may be useful for clinical decision because of its suggestive property for potential pathogenic capacity of Candida isolates. In this study, we simultaneously screened 411 clinical isolates of Candida spp. by microtiter plate (MTP), visual tube (TM) and congo red agar (CRA) methods for determining their ability to form biofilm and also evaluated the reliability of these methods in order to determine most suitable screening method. The accuracy of TM and CRA methods were also evaluated by using MTP as reference method. Of the 411 Candida spp., 159 (38.7%) displayed a biofilm-positive phenotype by MTP method. Sensitivity and specificity of the tube method were 68 and 98%, respectively and the positive predictive value (PPV) was 97% and the negative predictive value (NPV) was 83%. The sensitivity for congo red agar test was 79% and the specificity was 99%, and the PPV was 99% and the NPV was 88%. Tube method showed very good agreement for the isolates producing strong biofilm, whereas differentation of isolates producing weak biofilm was difficult. By the congo red method, classification of existing biofilm was problematic. Among the three methods studied, microtiter plate method may be suggested as the most sensitive method, which is easy to conduct and applicable as a routine process. Key words: Candida, biofilm, microtiter plate, tube method, congo red agar.

Background: Bacteria tend to live in assemblies called biofilms that aid bacterial virulence. Biofilms contribute to the development of antibiotic resistant urinary tract infection. Therefore, detection of biofilm production by urinary pathogens can assist the physicians to initiate the proper antimicrobial treatment.Methods: We conducted a prospective study that included patients with suspected urinary tract infection. Collected midstream urine samples were processed by standard microbiological techniques. Detection of biofilm production by the isolated uropathogens was conducted by tissue culture plate method (TCPM), tube method (TM) and Congo red agar (CRA).Results: A total of 43 (29.7%) isolated uropathogens showed positive biofilm formation by TCPM which was considered the gold standard for biofilm detection. When compared with the TCPM, TM truly identified 40 biofilm producers and 83 non-biofilm producers showing sensitivity and specificity of 93.0% and 81.4% respectively. The CRA truly identified 38 biofilm producers and 77 non-biofilm producers with sensitivity and specificity of 88.4% and 75.5% respectively.Conclusion: The TM was superior to CRA in biofilm detection and demonstrated better sensitivity and specificity results. Out of the investigated three phenotypic biofilm detection methods, the TCPM was the ideal method for detection of biofilm formation by uropathogens isolated from midstream urine samples. It can be used routinely in the microbiology laboratory with good specificity results and less subjectivity errors.

Urinary tract infections are an exceedingly common worldwide problem, caused mostly by Gram-negative bacteria, especially Escherichia coli. Microbial biofilms are considered a serious public health problem. The potential of uropathogenic E. coli (UPEC) to produce biofilm was explored in the present study. The Congo red agar, tube- and tissue culture plate methods were used to evaluate the formation of biofilm by E. coli isolates. Of the 155 isolates, 101, 106 and 90 isolates were positive for these three methods, respectively. Subsequently, the sensitivity of E. coli isolates to antimicrobial agents (amikacin, cefepime, cefixime, cefotaxime, cefpodoxime, ceftazidime, ceftriaxone, ciprofloxacin, nitrofurantoin, gentamycin, nalidixic acid, ofloxacin and pefloxacin) was tested. There was no difference in the rate of biofilm detection between Congo red agar method and tube method. The antibiotic sensitivity test revealed that the biofilm producing isolates were multi-drug resistant. The study emphasized the necessity for developing alternative therapeutic approaches to overcome multi drug resistance arising from biofilm formation of UPEC.

Investigation of the antibiotic resistance and biofilm-forming ability of Staphylococcus aureus from subclinical bovine mastitis cases.

Background: Biofilm production caused by bacteria plays a vital role in catheter associated urinary tract infection (UTI) or bacteriuria being responsible for persistence and recurrent infection. Biofilms forming bacteria are difficult to eradicate due to antimicrobial resistance to the commonly used antibiotic. Biofilms are currently estimated to be responsible for over 65% of nosocomial infections and 80% of microbial infections. This study aimed to perform biofilm detection on uropathogenic bacterial isolates among fistula patients attending National Obstetric Fistula centre Ningi and investigate the antimicrobial susceptibility pattern.&#x0D; Methods: A total of 217 strains of significant bacteriuria were isolated from vesico vaginal fistula (VVF) patients. A cross sectional study was conducted at the hospital. The urine samples were collected and cultured on CLED and blood agar media while confirmation was done using their biochemical reaction. The detection of biofilms formation on the isolates was performed using tube adherence and Congo red agar method. Antimicrobial susceptibility testing was carried out by disc diffusion method on Muller Hinton agar.&#x0D; Results: Out of 217 significant bacteriuria isolated, 38 strains produced biofilms;28 strains tested positive on tube adherence method while 15 strains were positive on Congo red agar method. Bacteria that produced biofim showed multiple drug resistance compared to the platonic bacterial cells. All the biofilm producers showed 100% resistant to septrin, ampiclox, gentamycin and amoxicillin. There was no significant value between tube adherence and Congo red agar method with P value &gt; 0.05.&#x0D; Conclusion: Biofilm detection should form part of routine testing while antimicrobial susceptibility testing is paramount on better choice of antibiotic therapy for proper management to reduce economic lost, treatment failure and drug resistance.

Biofilm producing bacteria are associated with many recalcitrant infections and are highly resistant to antimicrobial agents, hence notoriously difficult to eradicate. This study aimed at determining the biofilm forming capacities of bacterial isolates recovered in the raw wastewater and treated effluent from Wastewater Treatment Plants of Ahmadu Bello University Zaria using Tube Method (TM) and Congo Red Agar (CRA) method; and from the results, among the isolates recovered from the raw wastewater, TM detected 62.5% isolates as positive and 37.5% as negative for biofilm production, CRA detected 37.5% isolates as positive and 62.5% as negative for biofilm production. TM also demonstrated to be more suitable in detecting biofilm producing bacterial isolates from the treated effluent were it detected 50% isolates as positive and 50% as negative. However, CRA detected only 12.5% isolates as positive and 87.5% as negative for biofilm production. We therefore, conclude that the TM is more efficient and reliable for detection of biofilm producing bacteria in the laboratory when compared to CRA method and can be recommended as one of the suitable standard screening method for the detection of biofilm producing bacteria in laboratories.Keywords: Biofilm; Bacteria; Congo red agar and Tube method

Urinary tract infection (UTI) is one of the most common infectious diseases encountered in clinical practice. Emerging resistance of the uropathogens to the antimicrobial agents due to biofilm formation is a matter of concern while treating symptomatic UTI. However, studies comparing different methods for detection of biofilm by uropathogens are scarce. To compare four different methods for detection of biofilm formation by uropathogens. Prospective observational study conducted in a tertiary care hospital. Totally 300 isolates from urinary samples were analyzed for biofilm formation by four methods, that is, tissue culture plate (TCP) method, tube method (TM), Congo Red Agar (CRA) method and modified CRA (MCRA) method. Chi-square test was applied when two or more set of variables were compared. P < 0.05 considered as statistically significant. Considering TCP to be a gold standard method for our study we calculated other statistical parameters. The rate of biofilm detection was 45.6%, 39.3% and 11% each by TCP, TM, CRA and MCRA methods, respectively. The difference between TCP and only CRA/MCRA was significant, but not that between TCP and TM. There was no difference in the rate of biofilm detection between CRA and MCRA in other isolates, but MCRA is superior to CRA for detection of the staphylococcal biofilm formation. TCP method is the ideal method for detection of bacterial biofilm formation by uropathogens. MCRA method is superior only to CRA for detection of staphylococcal biofilm formation.

BackgroundCoagulase negative staphylococci were long regarded non-pathogenic as they are the commensals of human skin and mucosa but the recent changes in the medical practice and changes in underlying host populations, they are being considered significant pathogens associated with number of nosocomial infections. The objective of the study was to determine the species, antimicrobial susceptibility pattern, biofilm forming ability of the clinically significant CoNS isolates and to compare the different methods for the detection of biofilm formation.MethodsA total of 52 clinically significant CoNS isolates obtained from different units during a year period were studied. Characterization was done using standard microbiological guidelines and antimicrobial susceptibility was done following CLSI guidelines. Biofilm formation was detected by using three methods i.e. tissue culture plate method, congo red agar method and tube adherence method.ResultsAmong 52 isolates, S. epidermidis (52%) was the most common species which was followed by S. saprophyticus (18%) and S. haemolyticus (14%). Antimicrobial susceptibility pattern of CoNS documented resistance of 80% to ampicillin. Resistance to cefoxitin and ceftriaxone was observed in 58% of the isolates. Biofilm formation was observed in 65.38% of the isolates. The accuracy of Congo red agar and tube adherence method for the detection of biofilm formation was 82% and 76% respectively.ConclusionCoNS isolates obtained from clinical samples should be processed routinely and antimicrobial susceptibility testing should be performed. Multidrug-resistant CoNS are prevalent. All the three methods i.e. tissue culture plate, Congo red agar and tube adherence method can be used in detecting biofilm formation.

Background: Microorganisms growing in a biofilm are associated with chronic, recurrent infections, and health problems for patients with indwelling devices which are difficult to treat with antimicrobial agents. Staphylococcus species are the most common microorganisms isolated from these patients. This study was conducted to detect biofilm production in Staphylococcal isolates from orthopedic device-related infections (ODRI) and chronic osteomyelitis (CO) and correlation of antimicrobial susceptibility pattern between biofilm producers and nonbiofilm producers. Materials and Methods: A cross-sectional study was carried out at the Department of Microbiology in a tertiary care center after the Institutional Ethics Committee approval, from October 2014 to September 2016. Detection of biofilm was performed by Congo Red Agar (CRA), tube method (TM), and tissue culture plate (TCP) methods. Antimicrobial susceptibility test was performed by Kirby–Bauer disk diffusion method, and minimum inhibitory concentration for oxacillin and vancomycin was determined according to the Clinical Laboratory Standard Institute guidelines. Results: A total of 51 clinical isolates, consisting of 45 Staphylococcus aureus and 6 coagulase-negative Staphylococci (CoNS), were isolated from 47 CO and 4 ODRI patients of which 32 were methicillin-resistant S. aureus and 2 MRCONS. Biofilm production was detected in 22 isolates by TCP, 18 by TM, and 13 by CRA methods. Fifty percent ODRI isolates and 42.5% CO isolates were biofilm producers. The biofilm producers have lower antimicrobial sensitivity pattern in all except vancomycin. Conclusion: Biofilm producers were detected from 43.1% of total isolates with higher antimicrobial resistance pattern.

Objective: The most important bacteria of the conjunctival microbiota are Staphylococcus epidermidis, diphteroid rods, Corynebacterium spp. and Cutibacterium acnes. Especially biofilm formation of S. epidermidis is very important for contact lens related infections. For this purpose, we aimed to examine the changes in the presence of biofilm-forming S. epidermidis and other coagulase-negative staphylococci in conjunctival swabs taken before and after lens usage in 140 patients (90 hydrogel, 50 silicone hydrogel) who were prepared to wear lenses. Methods: Coagulase-negative staphylococci isolated from the conjunctival microbiota identified standard clinical microbiological methods, after identification of S.epidermidis strains with API Staph; Slime production was determined by Congo red agar, standard tube and molecular methods. Results: S.epidermidis was the most frequently isolated species in conjunctival microbiota before and after lens usage. Before lens usage, slime positive S. epidermidis strains were found as 45-50% but after lens usage it was 59% in hydrogel contact lens users and 70.2% in silicone hydrogel contact lens users. For the investigation of slime production, 82 (50.9%) of 161 S. epidermidis strains were found positive by using Congo red agar, 61 (37.8%) by standard tube method and 91 (56.5%) by molecular methods. Conclusion: The result of our study suggests that there are no significant changes in bacterial ratios before and after lens use, but bacteria such as S. epidermidis can predispose to infections by using slime production and contact lens factor. Also; molecular methods and Congo Red Agar method were found to be more reliable than the Standard Tube method.