Determination Of Antibiotic Susceptibility Patterns Research Articles

Isolation and Characterization of Bacterial Contaminants from Bone Marrow-Derived Mesenchymal Stem Cell Cultures

This study aimed to assess and manage bacterial contamination in multiple batches of mesenchymal stem cell (MSC) cultures derived from rabbit bone marrow. Routine visual inspection and microscopic examination were employed for the detection of the contaminated cultures. The contaminated cultures were inoculated on Nutrient agar and multiple isolated colonies were subjected to Gram staining and biochemical characterization. Further, molecular identification of the bacterial isolates was performed using polymerase chain reaction. The determination of antibiotic susceptibility patterns was conducted using the Kirby-Bauer disc diffusion method. Among the 351 mesenchymal stem cell culture (SCC) flasks monitored, only 1.42% were found to be contaminated. Based on the phenotypic and biochemical characterization, the major bacterial contaminants were identified as Staphylococcus aureus, Bacillus spp., and Escherichia coli infiltrating during various stages of cell processing. Antibiotic susceptibility patterns revealed varying responses among isolates, crucial for effective antimicrobial strategies and maintaining aseptic conditions in SCCs. The study emphasizes the importance of regular monitoring to maintain sterile environments, validate culture quality, and uphold safety standards. The findings indicate the need to establish stringent quality control measures, crucial for the successful translation of MSC research into clinical applications. The research advocates for continuous monitoring, adherence to SOPs, and further investigations into preventive strategies for ensuring the safety and efficacy of MSC-based therapies.

Bacteriological studies on methicillin -resistance Staphylococcus Aureus (MRSA) isolated from cow's mastitis milk

An enormous problem reported worldwide namely bovine mastitis caused by MDR( multi-drug resistant) S.aureus results in prolonged antibiotic treatment and livestock death. Mastitis caused by pathogenic S.aureus strains led to a focused study on surveillance of antibiotic susceptibility along with phenotypic and genotypic characterization. The isolation of Staphylococcus aureus to the determination of antibiotic susceptibility pattern from obtained cow’s milk samples was the aim of the current study. Cows affected by mastitis from different farms in Kalyuobia Governorate, one hundred milk samples were conducted for S.aureus isolation with a prevalence of 30% where 20% isolates were coagulase positive (CoPS) and 10% isolates were coagulase negative CoNS (Gram staining, oxidase, catalase, DNase, haemolysis, and the coagulase test were employed for bacterial identification). The majority of the strains (COPS) n=20 were profiled revealing antimicrobial sensitivity to be multidrug resistant. The occurrence of oxacillin susceptible mecA strains positive strains ( OS-MRSA) was revealed in 6 strains for the first time. Identification of MRSA strain by detection of mecA gene in the PCR .

Antimicrobial Resistance among Pregnant Women with Urinary Tract Infections Attending Antenatal Clinic at Levy Mwanawasa University Teaching Hospital (LMUTH), Lusaka, Zambia.

Introduction Globally, there is a growing concern over antimicrobial resistance (AMR) which is currently estimated to account for more than 700,000 deaths per year worldwide. AMR undermines the management of infectious diseases in general especially in pregnancy where significant bacteriuria continues to be a serious cause of maternal and perinatal morbidity and mortality. We therefore aimed to determine the prevalence of AMR and the associated factors among pregnant women with urinary tract infections (UTIs) attending antenatal clinic at a selected hospital in Lusaka, Zambia. Methods This was a hospital-based, cross-sectional study conducted between November 2018 and May 2019. Interviewer-administered questionnaire was used to assess the sociodemographic characteristics and behavioural characteristics. Laboratory tests were also conducted. Descriptive statistics of study participants were used to describe the characteristics of the respondents. Chi-square was used to assess the association between categorical variables. The logistic regression analysis was carried out to generate the adjusted odds ratio with 95% confidence interval. Results Overall (n = 203), the prevalence of UTI was 60% (95% CI: 53.3%–66.7%). The most isolated bacteria were E. coli (59%) and Klebsiella (21%). The prevalence of AMR was found to be 53% (95% CI: 46.1%–59.8%). The drugs highly resistant to antimicrobials were nalidixic acid (88.3%), ampicillin (77.8%), and norfloxacin (58.5%), while the least resistant drug was chloramphenicol (20%). There were no important significant predictors to AMR among pregnant women observed in this study. Conclusion We found high burden of AMR closely linked to observe high prevalence of UTI suggested in this small population. This suggests a need to develop integrated surveillance systems that aim for early and regular screening of pregnant women for UTI as well as concurrent determination of antibiotic susceptibility patterns. This is important to prevent complications that may endanger maternal and fetal health outcomes. Furthermore, further research is needed to explore reasons for this high prevalence of AMR including examining possible attribution to the misuse of drugs so as to inform, enforce, or adjust the prescription-only policies and enforce antimicrobial stewardship programs.

Public Health Risk Assessment of the Door Handles of the Community Pharmacies in Qassim Region, Saudi Arabia

Door handles are being reported to harbor a diverse group of microorganisms, mainly bacteria. Presence of pathogenic and antibiotic-resistant bacteria in the door handles carry risk to the health of the public. For this reason, a study was carried in the Qassim region of Saudi Arabia by isolating bacteria from the pharmacy door handles from four different areas. Total 100 samples were collected by wiping the door handles with a sterile cotton swab soaked in sterile water. Microorganisms were isolated using Blood agar and MacConkey agar and identified following standard microbiological procedure. Siemens MicroScan Walkaway system was used for determination of antibiotic susceptibility pattern. In total, 301 bacteria from 13 bacterial species were isolated and identified. The predominant bacterial species include Staphylococcus spp. 56.48% followed by Bacillus spp. 12.29% and Micrococcus spp. 10.30%. Gram-negative bacteria like Shigella sonnei and Salmonella paratyphiA were also isolated. Being the most predominant species, Antibiotic resistance pattern of 39 Staphylococcus spp. were determined. 38.46% of the Staphylococcus spp. were found to be resistant to Cefoxitin, and 30.76% were beta-lactamase producing. The results also indicated that about one -third of Staphylococcus spp. were methicillin resistant. The door handles of pharmacies in the Qassim region carry risk to the health of the public. Proper hygienic measures are recommended for the public health safety until doors are made automatic and touch-free.

Rapid identification of pathogens, antibiotic resistance genes and plasmids in blood cultures by nanopore sequencing

Bloodstream infections (BSI) and sepsis are major causes of morbidity and mortality worldwide. Blood culture-based diagnostics usually requires 1–2 days for identification of bacterial agent and an additional 2–3 days for phenotypic determination of antibiotic susceptibility pattern. With the escalating burden of antimicrobial resistance (AMR) rapid diagnostics becomes increasingly important to secure adequate antibiotic therapy. Real-time whole genome sequencing represents a genotypic diagnostic approach with the ability to rapidly identify pathogens and AMR-encoding genes. Here we have used nanopore sequencing of bacterial DNA extracted from positive blood cultures for identification of pathogens, detection of plasmids and AMR-encoding genes. To our knowledge, this is the first study to gather the above-mentioned information from nanopore sequencing and conduct a comprehensive analysis for diagnostic purposes in real-time. Identification of pathogens was possible after 10 minutes of sequencing and all predefined AMR-encoding genes and plasmids from monoculture experiments were detected within one hour using raw nanopore sequencing data. Furthermore, we demonstrate the correct identification of plasmids and blaCTX-M subtypes using de novo assembled nanopore contigs. Results from this study hold great promise for future applications in clinical microbiology and for health care surveillance purposes.

Role of AdeB gene in multidrug-resistance Acinetobacter

Objective The aim was to determine the role of the Ade B gene in multidrug-resistant Acinetobacter isolated from ICUs of Menoufia University Hospitals. Background Acinetobacter is a gram-negative bacteria that may cause serious infections. Numerous mechanisms are involved in its resistance to drug therapy. The active efflux mechanism is an important factor for development of multidrug resistance. The Ade ABC system is important efflux system in mediating such resistance. Therefore, the present study was designed to analyze the association between the expression level of Ade B gene and drug resistance in Acinetobacter. Materials and methods This case–control study was carried out in the period between October 2016 and October 2018. It was done at Clinical Pathology Department, Faculty of Medicine, Menoufia University Hospitals. The patients were selected from ICUs of Menoufia University Hospitals. The study included clinical samples collected from 614 patients admitted to ICUs. All clinical Acinetobacter isolates were further studied for determination of antibiotic susceptibility patterns and detection of Ade B gene by real-time PCR. Results Of the 614 samples, 70 (11.4%) Acinetobacter were isolated. Regarding antimicrobial resistance pattern, 61.4% of the Acinetobacter isolates were found multidrug and extensive drug resistant. There was significant increase in Ade B gene expression (P Conclusion AdeB gene plays a vital role in multidrug resistance in clinical Acinetobacter isolates. These results may benefit to design active efflux pump inhibitors. Moreover, implementation of strict microbial policies and infection control programs may prevent the rapid dissemination of this organism.

Characterization of carbapenem-resistant but cephalosporin-susceptible Pseudomonas aeruginosa.

In this study, mechanisms of carbapenem resistance in carbapenem-resistant but cephalosporin-susceptible (Car-R/Ceph-S) Pseudomonas aeruginosa were investigated. A total of 243 P. aeruginosa isolates were studied. The disk diffusion and agar dilution methods were used for determination of antibiotic susceptibility patterns. AmpC and efflux pump overproductions were detected by phenotypic methods. The presence of carbapenemase-encoding genes was detected by polymerase chain reaction (PCR). The expression of OprD, MexAB-OprM, and MexXY-OprM efflux pumps was assessed by real-time PCR. According to disk diffusion method, altogether 116 P. aeruginosa isolates (47.7%) were carbapenem-resistant and among them, 23 isolates (19.8%) were cephalosporin-susceptible. Carbapenemase producer was not detected. Overexpression of AmpC was detected in one (4.3%) isolate that was ceftazidime-susceptible but cefepime-resistant. Overexpression of MexAB-OprM and MexXY-OprM efflux pumps was detected in 12 (60.9%) and 16 (68.8%) of isolates, respectively. A total of 16 (68.8%) isolates showed decreased expression of OprD. The Car-R/Ceph-S P. aeruginosa did not develop by carbapenemase production. The resistance to carbapenem was mediated in our clinical isolates by decreased expression of OprD and overexpression of MexAB-OprM and MexXY-OprM efflux systems or the combination of these mechanisms.

Klebsiella pneumoniae carbapenemase production among K. pneumoniae isolates and its concern on antibiotic susceptibility

The emergence of Klebsiella pneumoniae carbapenemase (KPC) resistance has led to the countdown of activity of carbapenems, which were considered as drugs of last resort for infections caused by Enterobacteriaceae. The aims of the present study were the detection of KPC-production among K. pneumoniae isolates, select the appropriate method for its detection and assess the consequence of KPC production on the antibiotics susceptibility. One hundred and four non-duplicated K. pneumoniae isolates were collected from University teaching hospitals of Tabriz, Iran. The disk diffusion, E-test, and Modified Hodge test were performed for the determination of antibiotic susceptibility pattern, Minimum Inhibitory Concentrations (MICs) determination and the production of carbapenemase, respectively. BlaKPC-2 gene was detected by using PCR. High levels of resistance were observed towards co-trimoxazole (69.2%), followed by cefazolin (66.3%), ceftriaxone (65.4%), ofloxacin and ciprofloxacin (54.8%), gentamicin (50%), and amikacin (39.4%). According to the disk diffusion method, the frequency of imipenem and meropenem resistance was 31.7% and 32.7%, respectively. Colistin was the most effective antibiotic among panels of antibiotics tested. Imipenem MICs range, MIC50 and MIC90 were 0.19-32 μg/ml, 4 μg/ml, and 16 μg/ml, respectively. Modified Hodge test was positive in 24 (63.2%) isolate however, blaKPC-2 gene was detected in 8 (21.1%) carbapenem- resistant isolates. Results of the present study revealed a high rate of carbapenem- resistance in K. pneumoniae by phenotypic method, however the presence of one of the molecular, namely blaKPC-2 was not found as predominant cause. Therefore, their reliable detection should be the first priority to combat the infections. Being a simple test, the imipenem disk diffusion could be considered as an appropriate method for the detection of carbapenem-resistant isolates in the routine diagnosis.

Determination of Antibiotic Susceptibility Pattern of Clinical Isolates of Salmonella Typhi and Escherichia coli

Determination of Antibiotic Susceptibility Pattern of Clinical Isolates of Salmonella Typhi and Escherichia coli

Determination of antimicrobial resistance pattern and molecular characteristics of methicillin-resistant Staphylococcus aureus strains isolated from patients in a teaching hospital of Isfahan, Iran

BackgroundS. aureus seems to play a significant role in the pathogenesis of infection in hospitals setting. This study aimed to the investigation of the prevalence of S. aureus isolates and the determination of antibiotic susceptibility pattern and the different types of SCCmec in MRSA isolates obtained from a clinical sample in Isfahan, Iran. MethodsThis study was performed during January 2013 to March 2014 at tertiary care hospitals. S. aureus isolates were collected from the clinical samples. Determination of antibiotic susceptibility pattern was done by the disc diffusion method. Also, SCCmec typing was performed by PCR method. ResultsA total of 150 S. aureus isolates were collected from the different clinical sample. Among them, 41.3% (62/150) isolates were MRSA. The most sensitivity for MRSA isolates was to vancomycin with 90% sensitivity and the high rate of resistance was toward tetracycline in MRSA and MSSA isolates. All of MRSA isolates were MDR. The rate of SCCmec types IV, III, I and II among MRSA isolates were 44.4%, 40.7%, 11.1% and 3.7, respectively. ConclusionsThe results of the current study showed that S. aureus especially MRSA isolates with a high rate of resistance still remains an important healthcare problem. Majority of the isolates were community-acquired and belonged to Sccmec type.

Association of integrons with multidrug-resistant isolates among phylogenic groups of uropathogenic Escherichia coli

The aims of this study were to investigate the antibiotics susceptibility, multidrug- resistant (MDR) frequency and the association of integrons with MDR among phylogenic groups of uropathogenic E. coli (UPEC). In total, 176 non-duplicated UPEC isolates were collected from urinary tract infections (UTIs) specimens. The disk diffusion method was performed for determination of antibiotic susceptibility patterns. Phylogenetic grouping and the presence of integron-associated genes (int) were detected by the PCR technique. A high frequency of resistance was observed to cotrimoxazole (96.9%), ampicillin (85%), trimethoprim (80.1%) and cefazolin (79.6%); and 140 isolates (79.5%) were MDR. Carbapenems and fosfomycin were the most effective antibiotics. The majority of isolates (60.8%) belonged to the phylogenic group B2. Integrons were detected in 135 (76.7%) of isolates and, class I was the most common (63.6%) class. MDR isolates were found to be significantly associated with class І integrons. These isolates were found to be closely associated with the phylogenic group D (82%), however, the presence of class І integrons was higher among MDR isolates of the phylogroup B1. This pattern is believed to be due to other mechanisms such as the overexpression of the efflux pumps. Our findings show a significant correlation between MDR and the presence of class І integron. We conclude that class 1 integron plays an important role in the development of MDR UPEC, especially among the phylogroup B1.

Detection of blaPER, blaGES and blaVEB Genes in Shigella sonnei Isolates from Patients with Diarrhea and Determination of Antibiotic Susceptibility Pattern

Detection of blaPER, blaGES and blaVEB Genes in Shigella sonnei Isolates from Patients with Diarrhea and Determination of Antibiotic Susceptibility Pattern

High frequency of MRSA in surgical site infections and elevated vancomycin MIC

Abstract Background Methicillin-resistant staphylococcus aureus (MRSA) causes surgical site infections (SSIs) and complicates the treatment of these infections. Vancomycin is the drug of choice for infections due to MRSA but creep MIC of vancomycin may be associated with failure in antibiotic therapy. The aim of the present study was to determinate the prevalence, antibiotic susceptibility patterns of MRSA in patients suffering from SSIs and determination of vancomycin MIC in these isolates. Methods Detection of S. aureus in 100 aspirated specimens from SSIs was performed by the standard microbiology tests. MRSA was detected by phenotypic and molecular methods. The disk diffusion, E-test and agar dilution methods were performed for determination of antibiotic susceptibility patterns, the vancomycin MIC and oxacillin MIC. The results were interpreted according to guidelines of the Clinical and Laboratory Standards Institute (CLSI). Results Of 24 S. aureus isolates, 20 (83.33%) were recognized as the MRSA by 30 μg cefoxitin disk from 100 specimens and all were confirmed by PCR. High frequency of resistance was observed to clindamycin, erythromycin, gentamicin, ciprofloxacin and chloramphenicol while all isolates were susceptible to vancomycin, linezolid, and mupirocin. The range of vancomycin and oxacillin MICs were 0.25 to 2 and 0.5 to 128 μg/ml, respectively. Vancomycin-creep MIC was detected in two isolates from the superficial wound and surgical respiratory tract infections, and one of the patients died. Conclusion The findings of this study show a high frequency of MRSA in SSIs. Due to the elevated MIC of vancomycin, we suggest consumption of other effective drugs for the treatment of SSIs.

Frequency of MRSA in diabetic foot infections

Staphylococcus aureus is one of the most common bacterial pathogens isolated from diabetic foot infections (DFIs). The increasing prevalence of meticillin-resistant S. aureus (MRSA) in patients with diabetes is associated with complications. The aim of this study was to determine the prevalence of S. aureus in DFIs and antibiotic susceptibility patterns of MRSA and non-MRSA isolates. Identification of S. aureus and MRSA was performed by the phenotypic and molecular methods. The Kirby-Bauer and agar dilution methods were performed for determination of antibiotic susceptibility patterns. Thirty-four isolates of S. aureus were isolated from March 2014 to February 2015. The rate of MRSA was 38.23 % according to the disk cefoxitin and oxacillin agar dilution methods, and as by PCR method 12) 35.29 %), isolates were found to have the mecA gene. All MRSA and non-MRSA isolates were susceptible to linezolid and vancomycin. The resistance rate to ceftriaxone was high followed by amoxicillin-clavulanic acid, tetracycline, gentamicin, and erythromycin. The most common bacterial pathogen isolated from DFIs was S. aureus. To ensure effective treatment, accurate detection of MRSA is critical. Our findings showed that MRSA isolates had high-level resistance to antimicrobial agents and that appropriate antibiotic therapy, based on the antibiotic susceptibility pattern, is essential to ensure a good result.

Bacterial etiology and antibiotic susceptibility pattern of diabetic foot infections in Tabriz, Iran.

Aim: The aim of this study was to investigate anaerobic and aerobic bacteria profile and determination of antibiotic susceptibility pattern in aerobic bacteria.Method: Specimens were cultured using optimal aerobic and anaerobic microbiological techniques. Identification of bacterial isolates was performed by standard microbiological methods and antibiotic susceptibility testing was performed according to the guidelines of Clinical and Laboratory Standards Institute (CLSI).Result: 92 bacterial strains were isolated from 60 samples of diabetic foot ulcers. Predominant aerobic bacteria isolated from these infections were S. aureus (28%) followed by Enterobacteriaceae family (24%) including Escherichia coli (15%), Citrobacter spp. (4%), Enterobacter spp. (4%), and coagulase-negative Staphylococcus spp. (17%), Enterococcus spp. (15%), Pseudomonas aeruginosa (7%) and Acinetobacter spp. (4%). No Clostridium spp. were isolated and 4% Bacteroides fragilis obtained from anaerobic culture. All Gram-positive isolates were susceptible to linezolid while all Enterobacteriaceae showed sensitivity to imipenem.Conclusion: Most of DFIs specimens were poly microbial infection and predominant bacteria were S. aureus and B. fragilis. These wounds may require use of combined antimicrobial therapy for initial management.

Determination of antibiotic susceptibility pattern in Campylobacter jejuni and Campylobacter coli isolated from children with acute diarrhea

Background: The emergence of antimicrobial resistant Campylobacter populations, which become an important consideration on the use of antimicrobial agents, especially in veterinary and human medicine, has become a serious concern worldwide. For monitoring the drug resistance, there is a need to develop reliable and reproducible laboratory techniques. There are several methods including disk diffusion, broth micro-dilution, agar dilution, and E-test to determine in-vitro susceptibility profiles of Campylobacter to a range of antimicrobial agents. Objectives: Study the Campylobacter jejuni and Campylobacter coli from children with diarrhea and determine the antimicrobial susceptibilities of the isolates to clinically relevant antimicrobials. Materials and methods: Two hundred twenty stool samples of children with diarrhea were cultured on Preston agar and the isolated campylobacter species were identified by further standard identification test. Susceptibility testing was carried out using Kirby-Bauer disk diffusion method and E-test. Results: Fourteen Campylobacter strains were isolated (6.36%), of which nine (64.3%) were identified as C. jejuni and five (35.7%) as C. coli. Using disk diffusion, all the campylobacter isolates were fully resistant to cephalothin, oxacillin, and ampicillin followed by ceftazidime with resistance rate of 71.42%. Gentamicin and ciprofloxacin were the most effective antibiotics against both isolated campylobacter species. According to E-test results, Campylobacter isolates demonstrated the greatest resistance to cephalothin (92.85%), oxacillin (92.85%), and ampicillin (78.57%). Conclusions: Our study reveals a high-level correlation between the E-test and agar disk diffusion method in evaluating the resistance of Campylobacter species to tested antimicrobial agents. This study also suggests disk diffusion is a reliable and cost effective technique for determining the prevalence of resistance among Campylobacter isolates. Keywords: Antibiotic resistance, campylobacter, disk diffusion, E-test

Penicillinase producing Neisseria gonorrhoeae from St Thomas' Hospital 1976-1990--the first fifteen years.

To examine the penicillinase producing N. gonorrhoeae (PPNG) collected at St Thomas' Hospital from 1976-1990 and, by determination of antibiotic susceptibility pattern and application of three typing methods, examine the prevalence of different gonococcal types. Also to determine whether there is any relationship between antibiotic sensitivity, plasmid profile, auxotype and serovar. A total of 665 isolates of PPNG from patients attending the Department of Genitourinary Medicine at St Thomas' Hospital were characterised by antibiotic MIC, plasmid profile, auxotyping and serotyping. Penicillin MICs for 85% of all isolates were between 0.25 and 32 mg/l. The MIC of tetracycline for 60-80% of the isolates was < 1 mg/l. A small number of isolates had tetracycline MICs of 32 mg/l but MICs > 32 mg/l were not seen. Over 90% of the isolates were sensitive to the remaining three antibiotics tested, erythromycin, cefuroxime and spectinomycin. The 3.2 or 4.4 MDa plasmid with or without the 24.5 MDa conjugal plasmid was seen in all isolates until 1989/90 when a 2.9 MDa beta-lactamase encoding plasmid and the 25.2 MDa plasmid mediating tetracycline resistance were also recognised. Ninety-nine percent of all isolates belonged to one of four auxotypes, prototrophic, arginine, proline or proline/arginine requiring. An initial predominance of isolates with the 1A outer membrane protein was reversed in 1982 and 1B has remained predominant. Thirty two different serovars were identified among the 665 isolates, 14 belonged to serogroup 1A and 18 to 1B, and the eight most common accounted for 83.9% (554) of all isolates. Analysis of the results of combined typing methods showed there was an association between antibiotic resistance, plasmid profile and serogroup. The number of auxotypes and serovars detected in the collection, indicates the possibility that PPNG have been introduced from abroad or outside our local population. Temporal trends in the distribution of auxotype/serovar classes show that the total population of PPNG isolates is formed by a heterogenous mixture in which certain auxotype/serovar classes appear, disappear and may re-emerge. Others were present throughout in small numbers.