Antimicrobial Susceptibility Studies Research Articles

Comparison of fidaxomicin, metronidazole and vancomycin for initial episode and recurrence of Clostridioides difficile infection - An observational cohort study

ObjectivesThe main aim of this study was to compare the clinical outcomes of patients attended in our area with Clostridioides difficile infection (CDI) (sustained cure, recurrence or death) in relation to treatment to normal or hypervirulent C. difficile as a risk factor and to describe the resistance profile to metronidazole and vancomycin antibiotics in our hospital over a one-year period. MethodsA retrospective, cross-sectional and observational study was conducted between June 2022 and June 2023 to compare the clinical cure and/or recurrence of CDI in adult patients treated in a Spanish secondary Hospital depending on the prescribed antibiotic treatment. In addition, we performed an antimicrobial susceptibility study to vancomycin and metronidazole in all C. difficile isolated in bacterial culture. ResultsOut of 194 selected patients the treatments were as follow: 43.81 % vancomycin, 21.65 % metronidazole, 8.25 % a combination of both, 6.70 % fidaxomicin and 19.59 % were untreated. Vancomycin and fidaxomicin patients had higher odds ratio of prolonged hospitalization (p = 0.041 and p = 0.040, respectively). Fidaxomicin had increased odds of suffering another episode of C. difficile (p = 0.009) and it was inferior to metronidazole for recurrent CDI (rCDI) (p = 0.035).Resistance profile for C. difficile was 4.07 % for vancomycin and 3.49 % for metronidazole. Hypervirulent C. difficile was identified in 17 (8.76 %) patients with 29.41 % of mortality (5/17; p > 0.05). ConclusionFidaxomicin treated patients had statistically increased odds of rCDI. Compared to other treatments, fidaxomicin was inferior to metronidazole for rCDI in our cohort;Hypervirulent C. difficile was not associated with death.Vancomycin resistance of C. difficile statistically decreased, whereas metronidazole resistance did not vary during the studied period.

DISSEMINATION OF DIARRHEAGENIC BACTERIA IN COMMUNITY-BASED NATURAL WATER SOURCES AND WASTEWATER ENVIRONMENTS: A COMPREHENSIVE ANALYSIS IN UNIVERSITY OF NIGERIA, NSUKKA AND ITS METROPOLIS.

The presence of pathogenic strains abounds in our environment, arising from many sources. The study was aimed at identifying Vibrio species, E. coli, and other coliforms in various water sources within a university setting and its metropolis. Approximately 20 samples from roof-collected rainwater, municipal piped tap water, borehole water and 60 samples of sewage effluent from the central effluent water of University of Nigeria, Nsukka were systematically collected at intervals and subjected to bacteriological analysis. The samples underwent dilutions, and aliquots were inoculated on chromocult and thiosulfate-citrate-bile salts-sucrose (TCBS) agar. Simultaneously, 100 ml of each natural water sample underwent membrane filtration, followed by the inoculation of TCBS agar plates in duplicates. Both sets of culture plates were incubated at 37 °C for 24 h. Further biochemical characterization was performed after microscopy. Susceptibility profile was done using disk diffusion assay. Descriptive statistics were used in the aggregation of the results where necessary. Results revealed that each sample, when plated on chromocult agar, yielded a substantial number of colonies of E. coli (bluish colour) and other coliforms (pink-red colonies). Notably, wastewater gave a maximum yield of Vibrio cholera. Conversely, all significant pathogenic Vibrio species were recovered on TCBS agar inoculated with natural water samples, wastewater and sewage effluent, with isolation rates appearing independent of both time (in weeks) and collection points. Antimicrobial susceptibility studies disclosed that some of the isolates exhibited antibiotic resistance. The study underscores the need to install appropriate measures to mitigate the contamination of the environment. Keywords: Wastewater, Vibrio, Antimicrobial, Chromocult, Pathogen, Sewage

Successful eradication rate of Helicobacter pylori with empirical antibiotic treatment in pediatric patients from a Tertiary Hospital

To determine the success rate of first-line empirical eradication treatment against H. pylori in pediatric patients treated in a tertiary hospital. Retrospective descriptive study in patients with H. pylori infection detected in gastric biopsies and who had received first-line antibiotic treatment during the period 2017-2021. A negative result of an antigen test in stools or new biopsies after ≥ 1 month after completing treatment was considered a successful eradication. 82 patients with H. pylori infection were identified, of which 53 received eradication treatment. Of these, 26 (49%) were controlled with eradication tests after treatment with a success rate of only 38% (10/26). The eradication rate with the empirical regimens used was lower than expected which highlights the challenge of seeking more effective treatment strategies, including the study of antimicrobial susceptibility. Patient adherence to the follow-up protocol was also low, which should be reinforced in the future to ensure more appropriate clinical management.

Characterization of VIM, VEB and CTX-M Beta-lactamase Gene in Escherichia coli and Pseudomonas aeruginosa Isolated from Urine Samples of Patients Visiting a Tertiary Hospital in Abakaliki

The spread and convergence of multiple beta-lactamase genes across distinct resistant bacterial populations from various hosts and settings demonstrates increased risk of morbidity and mortality in humans. This study was undertaken to characterize blaVIM, blaVEB and blaCTX-M beta-lactamase gene in Escherichia coli and P. aeruginosa isolates from patients visiting a tertiary hospital in Abakaliki. A total of three hundred (300) urine samples were collected from patients and were subjected to bacteriological examination using culture, Gram staining and biochemical technique, for routine microbiological identification and further confirmed using the VITEK-2 Automated System (Biomerieux, France). Antimicrobial susceptibility studies were determined using the Kirby–Bauer disk diffusion method. All isolate were further screen for various beta-lactamase resistant gene by PCR using specific primer. Of the 300 urine samples collected, prevalence rate of 187 (62.3%) and 91 (30.3 %) E. coli and P. aeruginosa were recorded. The isolates exhibited 50.0-100% percentage of resistance to Amoxycillin-Clavulanic acid, Azetronam, Cefoxitin, Ceftriaxone and Piperacillin/tazobactam. The proportion of beta-lactamase gene in E. coli were as follows (VEB 143/76.5 %; CTX-M 175/93.5 %; VIM 77/41.2 %) while beta-lactamase gene in P. aeruginosa were as follows (VEB 91/100 %; CTX-M 63/69.2%; VIM 48/52.7 %). The presence of these gene in our study indicates the possibility of therapeutic failure, serious consequences for infection control and increased risk of morbidity and mortality in patients. Hence, continuous effort in hospital surveillance, infection control, and clinical audits must be conducted to fight against the rapid development and spread of antibiotic-resistant bacteria pathogens. Keywords: Beta-lactamase, Escherichia coli, Pseudomonas aeruginosa, VIM, VEB, CTX-M

Differences in Virulence Factors and Antimicrobial Susceptibility of Uropathogenic Enterococcus spp. Strains in a Rural Area of Uganda and a Spanish Secondary Hospital.

Enterococcus faecalis and Enterococcus faecium have become two of the most important agents of nosocomial diseases due to their constantly growing resistance. Enterococcal infections are associated with biofilms, which are intrinsically sensitive to antimicrobials. The main goal of this study was to compare and relate their capacity to form biofilm and their antimicrobial sensitivity, as well as their virulence factors and their implicated genes, of strains isolated from patients with urinary tract infection (UTI) in a rural hospital in Uganda and a secondary hospital in Spain. A prospective study was conducted with 104 strains of E. faecalis and E. faecium isolated from patients with suspected UTI and who presented leukocyturia at the Saint Joseph Kitgum hospital (Uganda) and at the Hospital Universitario Principe de Asturias (Spain). All microorganisms were identified in Spain by MALDI-TOF mass spectrometry. Antimicrobial susceptibility studies were carried out using the Vitek® 2 system (Biomériux, France). The biofilm formation capacity was studied by photospectrometry. Phenotypic and genotypic virulence factors were studied in all cases by PCR or expression techniques. In Uganda, we found a higher incidence of E. faecium (65.3%, n = 32), contrary to the situation found in Spain where most of the bacteria found belonged to E. faecalis (92.7%, n = 51). All E. faecalis strains were found to have very low levels of resistance to ampicillin, imipenem, and nitrofurantoin. However, E. faecium exhibited more than 25% resistance to these antibiotics. Although the esp gene has been shown in the results obtained to be an important initial agent in biofilm formation, we have also demonstrated in this study the intervention of other genes when esp is not present, such as the ace1 gene. No statistically significant relationships were found between the presence of agg and gelE genes and increased biofilm formation. The significant difference between the incidence of E. faecalis and E. faecium and biofilm formation, between samples from Spain and Uganda, shows us very different profiles between countries.

New definitions of susceptibility categories EUCAST 2019: clinic application.

In January 2019, the European Committee for the Study of Antimicrobial Susceptibility (EUCAST) introduced some changes in the definitions of clinical categories for antibiotic susceptibility. The objective of these changes was to improve the credibility of category "I", optimizing and lengthening the survival and use of available antibiotics in the face of increasing antimicrobial resistance. This article aims to describe and explain these changes in the EUCAST criteria as well as make a short review about the factors on which the antibiotic susceptibility criteria depend.

Prevalence and Antimicrobial Resistance of Campylobacter coli and Campylobacter jejuni Isolated from Pig Guts, Pig Feces, and Surface Swabs from the Cutting Tables at Slaughterhouse and Taverns in Southern Benin.

Campylobacter food-borne infections are a serious public health problem. In Benin, there is a proliferation of pork consumption in several forms. This study aims to determine the prevalence and the antimicrobial resistance of Campylobacter coli and Campylobacter jejuni strains isolated from pig guts, pig feces, and surface swabs from the cutting tables in southern Benin. For this purpose, 200 samples of pig guts, 40 samples of swabs from the cutting table surface, and 8 samples of pig feces were collected and subjected to bacteriological examination. The method used for the identification of bacteria was microbiological culture combined with molecular identification by PCR. The identified strains were then subjected to antibiotic susceptibility testing according to the methodology recommended by the EUCAST. Antibiotic profiles were compared between strains isolated from pig guts, pig feces, and cutting table surfaces on the one hand and among the different sampling sites on the other hand. The results obtained show that 47.6% of the samples analyzed were contaminated by Campylobacter spp. Molecular identification revealed 34.7% of Campylobacter coli and 9.3% of Campylobacter jejuni. The study of antimicrobial susceptibility showed resistance to ciprofloxacin, 44% to ampicillin, 23.9% to erythromycin, 11% to gentamicin, and 10.1% to amoxicillin + clavulanic acid. In total, 90.8% of the isolated Campylobacter strains were multidrug resistant. The use of antimicrobials in livestock production systems has increased considerably, which could explain, at least partially, the prevalence of Campylobacter and the resistance of strains to antibiotics. To limit the risk of Campylobacter food-borne infections, it is therefore important to include Campylobacter in the list of pathogens to be tested during sanitary quality control of meat and meat products in Benin.

Nanoemulsion-Based Hydrogels and Organogels Containing Propolis and Dexpanthenol: Preparation, Characterization, and Comparative Evaluation of Stability, Antimicrobial, and Cytotoxic Properties.

Recently, nanoemulsion-based gels have become very popular for dermal drug delivery, overcoming the disadvantages of conventional semi-solid drug forms. The aim of this study is to prepare and characterize nanoemulsion-based hydrogels and organogels containing combined propolis and dexpanthenol, and to compare their stability, antimicrobial, and cytotoxicity properties. Within the scope of characterization studies, organoleptic properties, drug content, morphology, pH, gel-sol conversion temperature, spreadability, viscosity, FT-IR, and release properties were evaluated in hydrogels and organogels. The characterization studies carried out were subjected to short-term stability evaluation at room temperature and refrigerator for 3 months. While no phase separation was observed in any of the formulations kept in the refrigerator, phase separation was observed in four formulations kept at room temperature. The release study successfully obtained an extended release for propolis and dexpanthenol. In the antimicrobial susceptibility study, Hydrogel 1 showed activity against S. aureus, while Organogel 1 showed activity against both S. aureus and S. epidermidis. In the cytotoxicity study against HDFa cells, both Hydrogel 1 and Organogel 1 were found to be nontoxic at low doses. These hydrogels and organogels, which contain propolis and dexpanthenol in combination for the first time, are promising systems that can be used in wound and burn models in the future.

Comparative In Vitro Study of Biofilm Formation and Antimicrobial Susceptibility in Gram-Negative Bacilli Isolated from Prosthetic Joint Infections.

ABSTRACTProsthetic joint infections (PJIs) are typically caused by microorganisms that grow in biofilms. Traditional antimicrobial susceptibility tests are based on the study of planktonic bacteria that might lead to missing the biofilm behavior and to a treatment failure. This study was designed to analyze the antimicrobial susceptibility of clinical Gram-negative bacilli (GNB) isolates from PJIs in planktonic and sessile states and the possible relationship between antimicrobial resistance and biofilm formation. A total of 46 clinical isolates from patients with PJIs (mainly hip and knee prostheses) plus three GNB ATCC isolates were studied. The Minimal Inhibitory Concentration (MIC), minimal bactericidal concentration (MBC), minimal biofilm inhibitory concentration (MBIC), and minimal biofilm eradication concentration (MBEC) were assessed using a previously published methodology. Almost all of the GNB clinical isolates tested were biofilm forming. Pseudomonas aeruginosa was the largest biofilm-forming species. A comparison of MBIC90 versus MIC90 shows an increase higher than 1- to -2-fold dilutions in most antimicrobials studied, and MBEC90 was significantly higher than MIC90, becoming resistant to all the antimicrobial drugs tested. Higher biofilm production values were obtained in antibiotic-susceptible Escherichia coli in comparison to their resistant counterparts. However, regarding the relationships between antimicrobial resistance and biofilm formation, our analysis showed that each strain differed. A high antimicrobial resistance rate was found among the GNB studied. Moreover, almost all bacterial isolates were in vitro biofilm formers. Although there was no significant association between biofilm and antibiotic resistance, multidrug-resistant isolates were found to be greater biofilm formers than non-multidrug-resistant isolates.IMPORTANCE This study is the first one to analyze a high number of isolates of Gram-negative bacilli that are the cause of prosthetic joint infection. The analysis includes biofilm development and antimicrobial susceptibility testing of both planktonic and sessile bacteria. The obtained results support the clinical knowledge about the treatment of these bacteria when biofilms are involved.

Virulence and antimicrobial resistance gene profiles of Staphylococcus aureus associated with clinical mastitis in cattle

Staphylococcus aureus (S. aureus) is the most prevalent microorganism associated with mastitis in cattle, which harbours several virulence factors and antibiotic resistance genes. The present study aimed to characterize S. aureus isolated from mastitic milk of the cattle for antibiotic resistance (blaZ and mecA), haemolysins (hla and hlb) and enterotoxins (sea, seb, sec, and sed) genes. A total of 69 staphylococci were isolated and phenotypically characterized for haemolytic properties on 5% sheep blood agar medium. Out of 69 isolates, 55 (79.71%) were identified as S. aureus by polymerase chain reaction assay. Among S. aureus, the majority of the isolates harboured the gene blaZ (92.73%), followed by coa (89.09%), hlb (60%) and hla (49.09%). Gene mecA responsible for methicillin resistance was detected in 23.64% of S. aureus isolates. Enterotoxin genes seb (9.09%), sec (1.82%) and sed (7.27%) responsible for food poisoning were detected at a comparatively lower rate and none of the S. aureus strain was found positive for sea. Additionally, antimicrobial susceptibility study of S. aureus against 18 antimicrobial discs showed maximum resistance to oxytetracycline, penicillin, and fluoroquinolone groups, contrarily, we observed maximum sensitivity to methicillin and cefuroxime antimicrobials. The high occurrence rate of S. aureus harbouring genes for virulence factors and antimicrobial resistance needs appropriate strategies to control the pathogen spread to the human population.

C6 Hydroxymethyl-Substituted Carbapenem MA-1-206 Inhibits the Major Acinetobacter baumannii Carbapenemase OXA-23 by Impeding Deacylation.

ABSTRACTAcinetobacter baumannii has become a major nosocomial pathogen, as it is often multidrug-resistant, which results in infections characterized by high mortality rates. The bacterium achieves high levels of resistance to β-lactam antibiotics by producing β-lactamases, enzymes which destroy these valuable agents. Historically, the carbapenem family of β-lactam antibiotics have been the drugs of choice for treating A. baumannii infections. However, their effectiveness has been significantly diminished due to the pathogen’s production of carbapenem-hydrolyzing class D β-lactamases (CHDLs); thus, new antibiotics and inhibitors of these enzymes are urgently needed. Here, we describe a new carbapenem antibiotic, MA-1-206, in which the canonical C6 hydroxyethyl group has been replaced with hydroxymethyl. The antimicrobial susceptibility studies presented here demonstrated that this compound is more potent than meropenem and imipenem against A. baumannii producing OXA-23, the most prevalent CHDL of this pathogen, and also against strains producing the CHDL OXA-24/40 and the class B metallo-β-lactamase VIM-2. Our kinetic and mass spectrometry studies revealed that this drug is a reversible inhibitor of OXA-23, where inhibition takes place through a branched pathway. X-ray crystallographic studies, molecular docking, and molecular dynamics simulations of the OXA-23-MA-1-206 complex show that the C6 hydroxymethyl group forms a hydrogen bond with the carboxylated catalytic lysine of OXA-23, effectively preventing deacylation. These results provide a promising strategy for designing a new generation of CHDL-resistant carbapenems to restore their efficacy against deadly A. baumannii infections.

Recommendations for the diagnosis and treatment of urinary tract infection in pediatrics. Part 2: Working group associated with the Antimicrobial Committee, Chilean Society of Infectology

The urinary tract infection (UTI) is one of the most common bacterial infections in childhood. An adequate diagnosis is essential to be able to carry out a rational, efficient and effective treatment, however, there is great heterogeneity in diagnostic methods, specifically in the study of antimicrobial susceptibility. The aim of these recommendations is to provide tools to homogenize the diagnosis criteria, susceptibility study and antimicrobial treatment of urinary tract infection in the pediatric population, with a rational use of antibiotics approach. In the first part, the recommendations regarding diagnosis were presented, such as sampling and cut-off points, as well as microbiological considerations for susceptibility study and management of UTI in pediatrics. This second part details the management of complications, UTI in special situations, and pharmacokinetic and pharmacodynamic considerations of antimicrobials to be prescribed in UTI.

Recommendations for the diagnosis and treatment of urinary tract infection in pediatrics. Part 1: Working group associated with the Antimicrobial Committee, Chilean Society of Infectology

The urinary tract infection (UTI) is one of the most common bacterial infections in childhood. An adequate diagnosis is essential to be able to carry out a rational, efficient and effective treatment, however, there great heterogeneity in diagnostic methods, specifically in the study of antimicrobial susceptibility. The aim of these recommendations is to provide tools to homogenize the diagnosis criteria, susceptibility study and antimicrobial treatment of urinary tract infection in the pediatric population, with a rational use of antibiotics approach. In the first part, the recommendations regarding diagnosis are presented, such as sampling and cut-off points, as well as microbiological considerations for susceptibility study and management of UTI in pediatrics. The second part details the management of complications, UTI in special situations, and pharmacokinetic and pharmacodynamic considerations of antimicrobials to be prescribed in UTI.

Factors Affect the Eradication Rate of Helicobacter pylori by Modified Quadruple Therapy: A Prospective Cohort Study.

ObjectiveThis study aimed to investigate related factors affecting the eradication rate of Helicobacter pylori (Hp) by modified quadruple therapy.MethodsBetween September 2020 and March 2021, 341 patients who were diagnosed with Hp infection and whose infections were confirmed by gastroscopy, a histological examination, and a C13-UBT without culturing and antimicrobial susceptibility studies received a two-week anti-Hp treatment, a modified quadruple therapy, in our department. The result of C13-UBT was rechecked 4 weeks after the drug withdrawal, and the patients were divided into two groups—a success group and a failure group—according to the final breath result. The general clinical information and related laboratory indexes of each patient were collected, and the factors affecting the eradication rate were analyzed.ResultsThe total clinical eradication rate was 80.06% (273/341), and the failure rate was 19.94% (68/341), correspondingly. Univariate analysis identified statistically significant differences between the two groups in serum 25-hydroxyvitamin D levels, presence of oral diseases, positive cytotoxin-associated gene A (CagA), and medical compliance (P < 0.05). Meanwhile, the use of a proton pump inhibitor (PPIs) and antibiotics was statistically different (P < 0.05). Logistic regression analysis revealed that vitamin D level (<20 ng/mL) [OR = 98.56, 95% CI (29.01–334.83), P < 0.001] and medical compliance [OR = 148.18, 95% CI (37.64–583.33), P < 0.001] were independent effecting factors for eradication rate.ConclusionSerum 25-hydroxyvitamin D level lower than 20 ng/mL may affect the success of eradication of Hp and is an independent risk factor for eradication failure.

High rates of multidrug resistance in bacteria associated with small animal otitis: A study of cumulative microbiological culture and antimicrobial susceptibility

The etiology of otitis in dogs and cats is multifactorial and complex, involving bacterial and fungal pathogens. As empiric antimicrobial prescription is a common practice when treating such cases, antimicrobial resistance may represent a complicating factor. The aim of this study was to describe microbiological features and susceptibility profiles of pathogens associated with 142 cases of external otitis, comprising 138 dogs and 4 cats.. The specimens were processed to identify bacterial and fungal etiologies following standard microbiological methods. Antimicrobial susceptibility was determined in vitro against 15 antibiotics and 3 antifungals. Further, Staphylococcus spp. isolates were screened for the detection of β-lactamase enzymes using cefinase paper discs. Pseudomonas spp. and isolates from Enterobacteriaceae family were screened for colistin (Polymyxin E) resistance and for the mcr-1-mediated colistin resistance gene by PCR. The presence of mixed cultures of Enterobacteriaceae, Pseudomonas spp. and Staphylococcus spp., and co-infections with Malassezia spp., emphasizes the polymicrobial etiology of external otitis in small animals. Emerging rates of multidrug resistance observed in almost 50% of the isolates may alert for a near future of challenging veterinary cases unresponsive to first-line antimicrobials. In addition, these results highlight a potential public health concern of multidrug resistant bacteria, given the proximity of pets and their owners. This study addressed central aspects of external otitis, providing microbiologists and clinicians updated information on the etiology and treatment of challenging cases of multidrug resistant bacteria. It also provides priceless surveillance value in monitoring resistant bacteria in small animals.

Disinfectant and Antimicrobial Susceptibility Studies of Staphylococcus aureus Strains and ST398-MRSA and ST5-MRSA Strains from Swine Mandibular Lymph Node Tissue, Commercial Pork Sausage Meat and Swine Feces.

Staphylococcus aureus (S. aureus) causes gastrointestinal illness worldwide. Disinfectants are used throughout the food chain for pathogenic bacteria control. We investigated S. aureus bioavailability in swine Mandibular lymph node tissue (MLT) and pork sausage meat (PSM), established susceptibility values for S. aureus to disinfectants, and determined the multilocus sequence type of MRSA strains. Antimicrobial and disinfectant susceptibility profiles were determined for 164 S. aureus strains isolated from swine feces (n = 63), MLT (n = 49) and PSM (n = 52). No antimicrobial resistance (AMR) was detected to daptomycin, nitrofurantoin, linezolid, and tigecycline, while high AMR prevalence was determined to erythromycin (50.6%), tylosin tartrate (42.7%), penicillin (72%), and tetracycline (68.9%). Methicillin-resistant S. aureus (MRSA) strains, ST398 (n = 6) and ST5 (n = 1), were found in the MLT and PSM, 4 MRSA in MLT and 3 MRSA strains in the PSM. About 17.5% of feces strains and 41.6% of MLT and PSM strains were resistant to chlorhexidine. All strains were susceptible to triclosan and benzalkonium chloride, with no cross-resistance between antimicrobials and disinfectants. Six MRSA strains had elevated susceptibilities to 18 disinfectants. The use of formaldehyde and tris(hydroxylmethyl)nitromethane in DC&R was not effective, which can add chemicals to the environment. Didecyldimethylammonium chloride and benzyldimethylhexadecylammonium chloride were equally effective disinfectants. ST398 and ST5 MRSA strains had elevated susceptibilities to 75% of the disinfectants tested. This study establishes susceptibility values for S. aureus strains from swine feces, mandibular lymph node tissue, and commercial pork sausage against 24 disinfectants. Since it was demonstrated that S. aureus and MRSA strains can be found deep within swine lymph node tissue, it may be beneficial for the consumer if raw swine lymph node tissue is not used in uncooked food products and pork sausage.

Piperacillin/tazobactum and cefotaxime decrease the effect of beta lactamase production in multi-drug resistant K. pneumoniae

BackgroundWorldwide, multi-drug resistant Klebsiella pneumoniae (K. pneumonia) and their virulence’s were contributed more in the multi-drug resistant effect. According to the World Health organization report, it is an emerging thread in developing countries and also comes under first ever critical list. In this context, the current study was concentrated on detection of extended spectrum beta lactamase (ESBL) producing strain and their antimicrobial susceptibility study of K. pneumoniae. Materials and methodsFirstly, the multi-drug resistant effect of the K. pneumoniae was identified from specific CLSI guidelines recommended antibiotics by disc diffusion method. Consecutively, the primary ESBL identification test was performed using ceftazidime and cefotaxime, followed by double disc combination and phenotypic confirmation tests using ceftazidime/clavulanic acid and cefotaxime/clavulanic acid. Finally, the minimum inhibition concentration of some important sensitive antibiotics were performed against selected K. pneumoniae was confirmed by micro broth dilution method. Results and conclusionsThe current result was most favorable to selected K. pneumoniae with more multi drug resistant characteristic nature. All the performed antibiotics were almost more sensitive to selected K. pneumoniae. The effective antibiotics of piperacillin was also exhibited more resistant effect against tested bacteria and it cleaved the bacterial enzyme clearly. The present result of primary ESBL identification test result was exhibited with ≤22 mm and ≤27 mm against ceftazidime and cefotaxime were observed respectively. Followed result of double disc combination and phenotypic confirmation experiments results were clearly stated that the selected K. pneumoniae was ESBL producer. The ceftazidime, cefotaxime and ceftazidime/clavulanic acid and cefotaxime/clavulanic acid were exhibited with merged zones and ≥5 mm zones around the combination disc when compared with disc alone were observed. All the ESBL detection test results were clearly indicated that the selected K. pneumoniae strain was ESBL producer.

High Rates of Multidrug Resistance in Bacteria Associated with Small Animal Otitis - A Study of Cumulative Microbiological Culture and Antimicrobial Susceptibility

High Rates of Multidrug Resistance in Bacteria Associated with Small Animal Otitis - A Study of Cumulative Microbiological Culture and Antimicrobial Susceptibility

Antibiotic Resistance Pattern of Pseudomonas aeruginosa Isolated from Clinical Specimens from a Tertiary Care Centre in Central Kerala with Special Reference to Carbapenemase Detection

Pseudomonas aeruginosa is inherently resistant to many drugs. It is now an emerging opportunistic pathogen of clinical relevance. The emergence of carbapenemases is another major concern. Initiation of appropriate therapy is of paramount importance thus highlighting the need of active surveillance for newer emerging resistance trends for better infection control. To study the resistance pattern of P. aeruginosa isolates obtained from lab specimens and to determine the production of ESBL and Carbapenemase among them. A hospital-based cross-sectional study was carried out in the Department of Microbiology, Government medical college Thrissur, among P. aeruginosa isolates obtained from lab specimens, from January 2018 – December 2018. 162 isolates were studied. Antimicrobial susceptibility testing was done by Kirby – Bauer disc diffusion method, extended-spectrum beta-lactamase (ESBL) production was confirmed by and phenotypic confirmatory disc diffusion test. Carbapenemase detection was done using the modified carbapenemase inactivation (mCIM) method. The obtained data was analysed. Among 162 isolates 83% were non-multidrug-resistant (MDR) strains and 17% were MDR strains. 22% of ceftazidime resistant isolates were ESBL producers. 6.2% isolates were resistant to imipenem. Among the imipenem resistant isolates, Carbapenemase production was seen in 30% isolates by mCIM test. According to our study, the most effective antibiotic against P. aeruginosa were imipenem and cefoperazone/sulbactam showing resistance in 6.3% and 6.9% isolates respectively. The diversity of antibiotic resistance mechanisms and the emergence of carbapenem resistance is a threat that limits treatment choices. This suggests the need for ongoing antimicrobial susceptibility studies in the future.

Bacterial spectrum analysis and antimicrobial susceptibility study of osteoradionecrosis of the jaw in Southern China

Osteoradionecrosis of the jaw (ORNJ) is one of the most common and serious complications after radiotherapy of head and neck malignancies due to the high incidence of nasopharyngeal cancer in Southern China. Clinicians lack understanding and consensus on anti-infective treatment in ORNJ lesions. This research aims to provide evidence for rational use of antibiotics by reviewing the bacterial spectrums and antimicrobial susceptibility test of ORNJ patients. We collected patient who was diagnosed with ORNJ from November 2012 to June 2019 in our hospital. Exudate or bone unexposed wound surface sampling, agar plates culturing, and susceptibility testing were analyzed. Descriptive statistics were used for data presentation. A total of 219samples were collected in our retrospective study. The most common cultured bacteria were Klebsiella pneumoniae (15.10%), Pseudomonas aeruginosa (13.54%), and Staphylococcus aureus (10.94%). Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 5.21% in the whole positive samples. Ticarcillin, Ofloxacin, Vancomycin, Tigecycline, and Meropenem were more susceptible than other antibiotics to treat uncontrollable infection. Our research provided objective evidence for understanding the types of local bacterial flora and drug susceptibility in ORNJ lesions and gave a guiding reference for empirical antibiotics medication.