Clinical Laboratory Standards Institute Research Articles

Synthesis and Characterization of Potent and Safe Ciprofloxacin-Loaded Ag/TiO2/CS Nanohybrid against Mastitis Causing E. coli

To improve the efficacy of existing classes of antibiotics (ciprofloxacin), allow dose reduction, and minimize related toxicity, this study was executed because new target-oriented livestock antimicrobials are greatly needed to battle infections caused by multidrug-resistant (MDR) strains. The present study aims to green synthesize a biocompatible nanohybrid of ciprofloxacin (CIP)-Ag/TiO2/chitosan (CS). Silver and titanium nanoparticles were green synthesized using Moringa concanensis leaves extract. The incorporation of silver (Ag) nanoparticles onto the surface of titanium oxide nanoparticles (TiO2NPs) was done by the wet chemical impregnation method, while the encapsulation of chitosan (CS) around Ag/TiO2 conjugated with ciprofloxacin (CIP) was done by the ionic gelation method. The synthesized nanohybrid (CIP-Ag/TiO2/CS) was characterized using standard techniques. The antibacterial potential, killing kinetics, cytotoxicity, drug release profile, and minimum inhibitory concentration (MIC) were determined. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed spherical agglomerated nanoparticles (NPs) of Ag/TiO2 with particle sizes of 47–75 nm, and those of the CIP-Ag/TiO2/CS nanohybrid were in range of 20–80 nm. X-ray diffractometer (XRD) patterns of the hetero system transmitted diffraction peaks of anatase phase of TiO2 and centered cubic metallic Ag crystals. Fourier Transform Infrared spectroscopy (FTIR) confirmed the Ti-O-Ag linkage in the nanohybrid. The zeta potential of CIP-Ag/TiO2/CS nanohybrid was found (67.45 ± 1.8 mV), suggesting stable nanodispersion. The MIC of CIP-Ag/TiO2/CS was 0.0512 μg/mL, which is much lower than the reference value recorded by the global CLSI system (Clinical Laboratory Standards Institute). The CIP-Ag/TiO2/CS nanohybrid was found to be effective against mastitis causing MDR E. coli; killing kinetics showed an excellent reduction of E. coli cells at 6 h of treatment. Flow cytometry further confirmed antibacterial potential by computing 67.87% late apoptosis feature at 6 h of treatment; antibiotic release kinetic revealed a sustained release of CIP. FESEM and TEM confirmed the structural damages in MDR E. coli (multidrug-resistant Escherichia coli). The CIP-Ag/TiO2/CS nanohybrid was found to be biocompatible, as more than 93.08% of bovine mammary gland epithelial cells remained viable. The results provide the biological backing for the development of nanohybrid antibiotics at a lower MIC value to treat infectious diseases of cattle and improve the efficacy of existing classes of antibiotics by conjugation with nanoparticles.

Microbial profile, antimicrobial resistance, and molecular characterization of diabetic foot infections in a university hospital.

Diabetic foot infections (DFIs) are among the most severe complications of diabetes. The aim of this study was to determine the etiological pathogens of DFIs in different Wagner's and IDSA/IWGDF grades, and to assess their antimicrobial susceptibility pattern together with molecular characterization of antibiotic resistance genes. A prospective study was conducted on 120 DFI patients at Main Alexandria University Hospital, Egypt. The aerobic and anaerobic etiological pathogens were determined using semi-quantitative culture and PCR respectively. The antimicrobial susceptibility pattern was done according to Clinical Laboratory Standards Institute guidelines. Detection of carbapenemases and class-1 integron genes was carried out by polymerase chain reaction (PCR). A total of 178 (124 aerobic, 54 anaerobic) pathogens were identified from patients with DFI, with an average of 1.82 isolates/subject. Among aerobic pathogens, Gram-negative predominated (98/124; 79%), of which Pseudomonas spp. and Proteus spp. were the most common. MRSA constituted more than 50% of Gram-positive isolates. Polymicrobial infection was found in 42 (42.9%) subjects. The proportion of Gram-negative bacteria and anaerobes increased with increased DFI grades and severity. Multidrug and extensively drug resistant isolates were observed in 86 patients (87.7%). PCR identified carbapenemases genes in 14 (11.7%) and class 1 integron in 28 (23.3%) DFI cases. Vancomycin, teicoplanin, linezolid were the most effective antimicrobial agents against Gram-positive pathogens, while colistin, imipenem, meropenem, and piperacillin-tazobactam were effective against Gram-negative pathogens. Multidrug and extensively drug resistant Gram-negative bacteria were the dominant pathogens among all DFI severity grades. However, the proportion of Gram-positive bacteria decreased with the severity of infection. The clinical role of our relatively high rate of anaerobes should be investigated. The results found in this study could be beneficial for designing future empiric antimicrobial protocols in relation to the severity of DFIs.

Cross-Resistance and the Mechanisms of Cephalosporin-Resistant Bacteria in Urinary Tract Infections Isolated in Indonesia.

Urinary tract infection (UTI) by antibiotic-resistant strains has become increasingly problematic, with trends that differ from country to country. This study examined cross-resistance and the mechanisms of cephalosporin resistance in UTI-causative bacteria isolated in Indonesia. Antibiotic susceptibility tests based on Clinical Laboratory Standards Institute (CLSI) standards weredone for UTI-causative strains (n = 50) isolated from patients in Indonesia in 2015-2016 andshowed resistance against the third-generation cephalosporin. Mechanistic studies were carried out to confirm the presence of extended-spectrum β-lactamase (ESBL) genes, carbapenemase-related genes, the fosA3 gene related to fosfomycin resistance, and mutations of quinolone-resistance-related genes. IsolatedUTI-causative bacteria included Escherichia coli (64.0%), Pseudomonas aeruginosa (16.0%), Klebsiella pneumoniae (10.0%), and others (10.0%). These strains showed 96.0% susceptibility to amikacin, 76.0% to fosfomycin, 90.0% to imipenem, 28.0% to levofloxacin, 92.0% to meropenem, and 74.0% to tazobactam/piperacillin. ESBL was produced by 68.0% of these strains. Mechanistic studies found no strains with carbapenemase genes but 6.0% of strains had the fosA3 gene. Seventy-two % of the strains had mutations in the gyrA gene and 74.0% in the parC gene. Most E. coli strains (87.5%) had Ser-83 → Leu and Asp-87 → Asn in gyrA and 93.8%of E.coli had Ser-80 → Ile in parC. There were significant correlations among mutations in gyrA and parC, and fosA3 gene detection (P < 0.05), respectively. To our knowledge, this is the first mechanistic study of antibiotic-cross-resistant UTI-causative bacteria in Indonesia. Further studies with a longer period of observation are necessary, especially for changes in carbapenem resistancewithout carbapenemase-related genes.

Increased Isolation of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli From Community-Onset Urinary Tract Infection Cases in Uttarakhand, India.

Background: Management of community-acquired urinary tract infection (CA-UTI) relies heavily on empirical antibiotic therapy. Knowledge of the proportion of drug-resistant isolates especially extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli), and various risk factors for acquisition are essential.Method: Outpatient-treated CA-UTI cases were enrolled (continuously for three months), and microbiological analysis of urine sample was performed for significant bacterial growth followed by identification of conventional and matrix-assisted laser desorption/ionization-time of flight (MALDI-ToF) spectrometry method. Subsequent drug resistance and phenotypic ESBL detection were as per guidelines of the Clinical Laboratory Standard Institute (CLSI, USA). Univariate and multivariate analyses (logistic regression) of known and relevant risk factors of ESBL E. coli were performed as per standard statistical technique, using the SPSS computer package (IBM Corp., Armonk, NY). Results: Two hundred and forty-one samples (of 694 samples) yielded significant growth. Sixty-one of 131 (46.6%) E. coli isolates were found to be ESBL producers. Non-beta-lactam antibiotic resistance in ESBL producers was high compared to non-ESBL producers (e.g., 88.5% vs 42.3% for quinolone resistance, 80.3% vs 34.3% for gentamicin resistance, etc.). Multivariate analysis (after univariate analysis detected probable factors of a likely ESBL model) indicated significant associations of ESBL-producing E. coli with advancing age (>55 years), prior hospitalization in last one year, use of antibiotics in previous six months, and presence of comorbid illness such as diabetes mellitus and chronic lung disease.Conclusion: High proportion of our community-acquired uropathogens are ESBL-producing E. coli and likely resistant to important antimicrobial agents such as quinolones, gentamicin, etc. Factors like advancing age, prior hospitalization, and antibiotic use, as well as comorbidities such as diabetes and chronic lung disease, may be strongly associated with ESBL E. coli and should be remembered while administering or preparing guidelines for empiric management of CA-UTI subjects.

Antibiotic resistance in Pakistan: a systematic review of past decade

BackgroundDuring the last six decades, extensive use of antibiotics has selected resistant strains, increasing the rate of fatal infectious diseases, and exerting an economic burden on society. This situation is widely accepted as a global problem, yet its degree is not well elucidated in many regions of the world. Up till now, no systemic analysis of Antimicrobial resistance (AMR) in Pakistan has been published. The current study aims to describe the antibiotic-resistance scenario of Pakistan from human samples of the last 10 y, to find the gaps in surveillances and methodology and recommendations for researchers and prescribers founded on these outcomes.MethodsOriginal research articles analyzed the pattern of Antibiotic resistance of any World Health Organization (WHO) enlisted priority pathogens in Pakistan (published onward 2009 till March 2020), were collected from PubMed, Google scholar, and PakMedi Net search engines. These articles were selected based on predefined inclusion and exclusion criteria. Data about the study characteristics and antibiotic-resistance for a given bacterium were excluded from literature. Antibiotic resistance to a particular bacterium was calculated as a median resistance with 95% Confidence Interval (CI).ResultsStudies published in the last 10 y showed that Urinary Tract Infection (UTI) is the most reported clinical diagnosis (16.1%) in Pakistan. E. coli were reported in 28 (30.11%) studies showing high resistance to antibiotics’ first line. Methicillin-resistant Staphylococcus aureus (MRSA) was found in 49% of S. aureus’ total reported cases. Phenotypic resistance pattern has mostly been evaluated by Disk Diffusion Method (DDM) (82.8%), taken Clinical Laboratory Standards Institute (CLSI) as a breakpoint reference guideline (in 79.6% studies). Only 28 (30.11%) studies have made molecular identification of the resistance gene. blaTEM (78.94% in Shigella spp) and blaNDM-1 (32.75% in Klebsiella spp) are the prominent reported resistant genes followed by VanA (45.53% in Enterococcus spp), mcr-1 (1.61% in Acinetobacter spp), and blaKPC-2 (31.67% in E. coli). Most of the studies were from Sindh (40.86%), followed by Punjab (35.48%), while Baluchistan’s AMR data was not available.ConclusionOutcomes of our study emphasize that most of the pathogens show high resistance to commonly used antibiotics; also, we find gaps in surveillances and breaches in methodological data. Based on these findings, we recommend the regularization of surveillance practice and precise actions to combat the region’s AMR.

Rising antimicrobial resistance pattern among the bacteria isolated from wound cases of domesticated animal in India

Antimicrobial resistance gained by the microorganisms is a global threat, which leads to economic loss as there will be treatment failure, loss of life, discovery of newer and better antimicrobials of any infections as there is need for discovery of newer and better antimicrobials. A total of forty five samples were collected from clinical wound cases in and around Parbhani Veterinary Hospitals. The total of 39 Gram negative and 17 Gram positive isolates includes Pseudomonas (24), E. coli (15) and Staphylococcus (17) spp, were confirmed by biochemical characterization. Susceptibility of isolates to seven antibiotics was tested using disc diffusion method according to the guidelines defined by Clinical Laboratory Standard Institute. Pseudomonas Isolates showing resistance to antibiotic for Ceftazidime, Levofloxacin were for E.coli isolates showing resistance to antibiotics Erythromycin, Tetracycline and For Staphylococcus isolates Penicillin and Enrofloxacin were resistance.

The antibacterial effects of vitamin D3 against mutans streptococci: an in vitro study.

This study aims to evaluate the antimicrobial effects of the cholecalciferol vitamin D3 against Streptococcus sobrinus (Strep. sobrinus) and Streptococcus mutans (Strep. mutans) bacteria in vitro that is considered the main causative bacteria in dental caries development. The antimicrobial effects of vitamin D3 were evaluated against Strep. sobrinus and Strep mutans using the agar disc diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of vitamin D3 were determined using a microdilution method following the guidelines by the Clinical Laboratory Standards Institute (CLSI). Scanning electron microscope (SEM) was used to evaluate the morphological changes of bacterial cells following exposure to vitamin D3. Strep. sobrinus was more sensitive to vitamin D3 compared to Strep. mutans bacteria. The MIC values of vitamin D3 against Strep. sobrinus and Strep. mutans were 60 μg/ mL and 250 μg/mL respectively whereas the MBC values were 120 μg/mL and 500 μg/mL, respectively. Moreover, significant changes in the bacterial morphology were observed in treated bacterial cells with vitamin D3 as compared to the untreated control bacteria using SEM. These findings suggested that vitamin D3 has excellent antimicrobial effects against Strep. sobrinus and Strep. mutans and may be considered as a promising compound in the prevention of dental caries in the future. Further research is recommended to elucidate the mechanism of vitamin D3 on these bacteria.

Correlation of nosocomial infection with prolonged hospital stay in Kano Nigeria

Nosocomial infections or Health Care prolonged hospital stay and has been implicated in increase in socio-economic disturbance, long term disability, and increased mortality rate. There is paucity information on the burden of HCAIs because of poorly developed surveillance systems and inexistent control methods. We aimed to investigate the prevalence of nosocomial infection due to prolonged hospital stay in selected tertiary hospitals of Kano metropolis. Retrospective data were collected from three hospitals with a total number of admitted patients and the number of prolonged hospital stays during the month of study. A total of 401 clinical samples collected from patients admitted for ≥14 days and the age of ≥18 years from all study sites. Examples include wound swabs, urine samples, urine catheters, and nasal intubation. All the samples were processed by the standard bacteriological laboratory procedure of the Clinical laboratory standard institute. The results showed that the percentage of prolonged hospital stay in Kano 40.34%, Murtala Muhammad Specialist Hospital (MMSH) 50.54% with the least at Muhammad Abdullahi Wase Specialist (MAWSH) 28.91%. Age served as significant factors for acquired HCAIs; participants aged were 41- 70 years have a higher prevalence of nosocomial infections. From 138 positive isolates observed, Murtala Muhammad Specialist Hospital (MMSH) has height nosocomial infection of 41.4%, with the least Aminu Kano Teaching Hospital (AKTH) has 29%. Among the Site of infection, 34.8% isolates were wounds Swabs (SSIs), urine (UTI) 31.2%, an least was nasal intubation 11.6%. Among pathogens isolated E. coli is the most prominent organism with 26.1% and the least Streptococcus pyogenes (7.9%). This study showed that the prevalence of Prolong hospital stay in Kano was 40.34%, AKTH 39.53% and MAWSH 28.91%. The prevalence of nosocomial infection was 34.3%. Gram-negative bacteria were the predominant isolates.

Evaluation and validation of Biolog OmniLog® system for antibacterial activity assays.

Minimal inhibitory concentration of antimicrobials, determined by the broth microdilution method, requires visual assessment or absorbance measurement using a spectrophotometer. Both procedures are usually performed manually, requiring the presence of an operator to assess the plates at specific time point. To increase the throughput of antimicrobial susceptibility testing, and concurrently convert into an automatic assay, the Biolog OmniLog® system was validated for a new, label-free application using standard 96-well microplates. OmniLog was evaluated for its signal strength to ensure that the signal intensity, detected and measured by the system's camera, was satisfactory. Variability due to the plate location inside the OmniLog incubator, as well as variation between wells, was investigated. Then the system was validated by determining the minimal inhibitory concentration of ciprofloxacin, piperacillin and linezolid against a selected Gram-negative and Gram-positive strains. No significant difference was observed in relation to position of the plates within the system. Plate edge effects were noticeable, thus the edge wells were not included in further experiments. Minimal inhibitory concentration results were comparable to those obtained by conventional protocol as well as to values defined by the Clinical Laboratory Standards Institute or published in the literature.

Antimicrobial Susceptibility Pattern of Gram-Negative Bacteria Causing Lower Respiratory Tract Infections in Kathmandu University Hospital.

Respiratory tract infection due to Gram-negative bacteria is a common cause of morbidity and mortality worldwide. This study was carried out to determine the antimicrobial susceptibility pattern of Gram-negative bacteria from patients with lower respiratory tract infection visiting Kathmandu University Hospital. A total of 3,403 respiratory samples including sputum and endotracheal aspirates were processed and antibiotic resistance pattern was determined following Clinical Laboratory Standard Institute guidelines. Patients' information was obtained after informed consent. Growth of Gram-negative bacteria was 210 (6.17%). 83(39.52%) were Klebsiella pneumoniae followed by Escherichia coli, Pseudomonas aeruginosa, Acinetobacter species, Klebsiella oxytoca, Enterobacter species, Proteus mirabilis and Haemophilus influenzae. 151(71.90%) isolates were multidrug resistant. None of the strains were resistant to colistin. 51(24.29%) were resistant to carbapenem and out of these 3(1.43%) were metallo-? lactamase producers. 89(65.92%) of the patients having both pneumonia along with other respiratory illnesses were above 60 years of age indicating that old age might be a predisposing factor. (p value is less than 0.0001). 92(81.42%) of patients of age above 60 years had multidrug resistant isolates indicating that old age might be a predisposing factor for getting infection my multidrug resistant isolates. (p value equals 0.0012) Among 36 diabetic patients 33(91.67%) had multidrug resistant isolates. Whereas out of 174 non-diabetic patients only 118(67.82%) had multidrug resistant isolates (p value equals 0.0037). Multidrug-resistant Gram negative bacteria were observed in respiratory samples. Effective treatment of lower respiratory tract infection need detailed microbiological diagnosis and drug susceptibility testing.

Evaluation of antibiotic usage in skin and soft-tissue infections and its antimicrobial susceptibility testing: A hospital-based cross-sectional study

Aim: To evaluate the antibiotic usage in skin and soft-tissue infections (SSTIs) and to study the sensitivity pattern of identified microorganisms from antimicrobial susceptibility testing (AST) data. Materials and Methods: This was a cross-sectional study carried out in the Inpatient Department of General Surgery at Owaisi Hospital & Research Center, Hyderabad, for 6 months to collect 50 swab samples aseptically from the subjects with diverse SSTIs at the day of admission before the administration of antibiotics, and AST was done using Kirby Bauer disc diffusion method based on the guidelines of Clinical Laboratory Standard Institute (CLSI). Results: Of the 50 swab samples, 43 were culture positive and 7 were culture negative, and the highest number of cases was of cellulitis (14.28%). The most commonly isolated pathogen was Staphylococcus aureus (30.23%). On the basis of antibiotic sensitivity testing, we found that Ciprofloxacin was the most potent drug, followed by Ceftriaxone and Amikacin, for overall bacterial isolates. In our study, the treatment adhered to IDSA guidelines in 50% of cases and we found that many antibiotics were resistant. In cases of gangrene and abscess, a striking deviation from the guidelines (60% and 77.7%, respectively) was seen. Conclusion: This study guided us toward an appropriate treatment plan for the management of some SSTIs. The disproportionate and tedious use of antibiotics should be abstained as this may drive the evolution of resistant microorganisms that are even more difficult to get rid of.

Prevalence of Enterobacteriaceae spp. and its multidrug-resistant rates in clinical isolates: A two-center cross-sectional study.

Enterobacteriaceae spp., owing to their high durability and antibiotic-resistant mechanisms, are described as an eminent part of health treatments in hospital-acquired infections. This study aimed to estimate the prevalence of clinical isolated Enterobacteriaceae spp., and their multidrug-resistant rate in the north of Iran. In this cross-sectional study, over two years (2017-2019), clinical isolates were collected and Enterobacteriaceae spp. were identified using the standard media culture and Analytical Profile Index (API 20E) kit from two centers in the north of Iran. Isolates were confirmed by targeting the rpoB gene. Moreover, the susceptibility patterns of isolates were assessed using disc diffusion methods according to the Clinical Laboratory Standard Institute (CLSI) guidelines. Out of 2645 clinical specimens, 297 (11.2%) were confirmed as Enterobacteriaceae spp. containing Eshershia. coli 93 (31%), Citrobacter freundii 65 (21.9%), Klebsiella pneumoniae 48 (16.2%), Enterobacter spp. 43 (14.5%), and Proteus spp. 23 (7.7%). As much as 8.7% of other spp. Ampicillin (81.1%) and cephalexin (80.9%) have been shown to have the greatest resistant, and nalidixic acid (65%) and amikacin (59.2%) were the most sensitive drugs. Multidrug-resistance (MDR) strains are more isolated in the Burn and Burn intensive care unit (BICU) than other wards. The MDR frequency in Bouali and Zareh hospitals were 65 (49.61%) and 130 (78.31%), respectively. Considering the high isolation rates of MDR Enterobacteriaceae spp., preventive measures need to be taken to remove the mentioned bacteria from hospital wards.

Nasal Carriage of Staphylococcus aureus in Different Age Groups among Healthy School Children and its Antimicrobial Susceptibility Pattern

Introduction: Staphylococcus aureus (S.aureus) is associated with increased risk for acquiring invasive disease. There exists an increasing prevalence of resistant community acquired S.aureus infections due to the nasal colonisation of S.aureus and Methicillin-Resistant S.aureus (MRSA) worldwide. Aim: To evaluate the prevalence rate of S.aureus and MRSA nasal colonisation among healthy school children and to determine its antibiotic susceptibility rate of the S.aureus isolates. Materials and Methods: The community based cross-sectional study was conducted among 344 school going children of 5-16 years of age. Samples were obtained from the anterior nares from each child and cultured on Blood Agar (BA) and Mannitol Salt Agar (MSA). Antibiotic susceptibility pattern of S.aureus was done by Kirby-Bauer disc diffusion method. MRSA detection was done through Cefoxitin 30 μg discs along with MIC for Oxacillin and Vancomycin simultaneously according to Clinical Laboratory Standard Institute (CLSI). Results: Of the 344 children, 26 (7.55%) were found to be with nasal carriage for S.aureus of which MRSA was found to be in 12 (3.48%) isolates. S.aureus isolates exhibited resistance to multiple classes of antibiotics including Penicillin (100%), Co- trimoxazole (50%), Ciprofloxacin (15.4%), Vancomycin (7.7%), Clindamycin (7.7%), Gentamycin (7.7%). No resistance to Linezolid was observed. Conclusion: A relatively high rate of nasal carriage of S.aureus in children of age group 5-10 years was observed when compared to children of age group 11-15 years. With the risk involved transmission of infection and resistance to many classes of antibiotics among S.aureus strains exists and hence, emphasis needs to be laid to design control measures, continued surveillance and its eradication.

Çanakkale’de Tonsillofarenjitli Hastaların Boğaz Kültürlerinden İzole Edilen Beta Hemolitik Streptokokların Grup Dağılımlarının ve Antibiyotik Direnç Profillerinin Belirlenmesi§

Objective: Group A, C and G beta- hemolytic streptococci (BHS) are bacterial agents of tonsillopharyngitis, and cause various diseases and increase morbidity and mortality. In this study, we aimed to determine the percentage of group distribution and the rate of antibiotic resistance of BHS identified from the throat cultures of patients with acute tonsillopharyngitis. Method: The throat swabs were collected from 200 patients with tonsillopharyngitis aged 1-80 years between October 2017 and May 2018. Bacterial isolates were identified by conventional methods such as Gram staining, bacitracin-trimethoprim sulfamethoxazole, catalase, and L-pyrrolidonyl β-naphthylamide. Latex agglutination test was used for serogrouping BHS. The antibiotic susceptibility profiles of BHS were determined by Kirby Bauer disc diffusion method. Streptococcus pyogenes ATCC 19615 strain was used as a control. Inhibition zone diameters were evaluated according to the Clinical Laboratory Standards Institute (CLSI) criteria. Results: Thirty-four (17%) BHS were isolated from 200 throat swap specimens.Distribution percentages of BHS group were determined as 44.1% (15) for A, 29.4% (10) C, 23.5% (8) G and 2.9% (1) F. All isolates were 100 % susceptible to penicillin, vancomycin and levofloxacin. The highest resistance (29.4%) was found against ampicillin followed by clindamycin (26.5%), erythromycin (23.5%), amoxycillin-clavulanic acid and tetracycline (14.7%), cefotaxime and ceftriaxone (11.8%), clarithromycin (8.8%) and chloramphenicol (2.9%). Conclusion: This study revealed that Group C, and Group G Streptococci had lower resistance to some antibiotics than Group A Streptococci. Based on the findings, the BHS group distributions and antibiotic resistance profiles should be repeated at certain intervals and precautions should be taken with public health surveillance studies

Comparative Performance of Four Nucleic Acid Amplification Tests for SARS-CoV-2 Virus.

COVID-19 is caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), which was discovered in 2019 and spread around the world in a short time. SARS-CoV-2 nucleic acid amplification tests (NAATs) have been rapidly developed and quickly applied to clinical testing of COVID-19. Aim of this study was to evaluate the performance of four NAAT assays. Limit of detection (LOD), precision, accuracy, analytical specificity and analytical interference studies on four NAATs (Daan, Sansure, Hybribio, and Bioperfectus) were performed according to Clinical Laboratory Standards Institute protocols and guidelines. The four NAATs were compared using 46 clinical samples. The LOD of the N gene for Daan, Sansure, and Hybribio was 500 copies/mL, and that for Bioperfectus was 1,000 copies/mL. The LOD of the ORF1ab gene for Daan, Bioperfectus, and Hybribio was 3,000 copies/mL, and that for Sansure was 2,000 copies/mL. A good precision was shown at the concentration above 20% of the LOD for all four NAATs, with all individual coefficients of variation below 3.6%. Satisfactory results were also observed in the accuracy, analytical specificity, and analytical interference tests. The results of the comparison test showed that Daan, Sansure, and Hybribio NAATs could detect the samples with a specificity of 100% (30/30) and a sensitivity of 100% (16/16), whereas Bioperfectus NAAT detected the samples with a specificity of 100% (30/30) and a sensitivity of 81.25% (13/16). However, no significant difference in sensitivity was found between Bioperfectus NAAT and the three other NAATs (p > 0.05). The four SARS-CoV-2 NAATs showed comparable performance, with the LOD of the N gene lower than the LOD of the ORF1ab gene.

Antibiotic Resistance of Typhoidal Salmonella Isolated from Humans in Kaduna and its Associated Factors

Background: Pathogenic Salmonella species cause various types of infections ranging from mild gastroenteritis to life- threatening typhoid fever caused by Salmonella typhi , or paratyphoid fever caused by S. paratyphi A, B or C; of which S . paratyphi A is prevalent. Currently, treatment of typhoid infection is being hampered by the emergence of multidrug-resistant strains, while vaccines provide only temporal or partial protection. Objective: The aim of the study was to determine antibiotic resistance of typhoid causing Salmonella isolated from human stool. Methodology: A cross-sectional descriptive study was carried out in the capital city of Kaduna State, Nigeria. Questionnaires were administered to 300 consenting individuals; comprising 250 patients and 50 volunteering healthy individuals, to obtain relevant socio demographic and clinical information. Stool specimens were equally collected in sampling containers for isolation of typhoidal Salmonella on Salmonella Shigella Agar. Suspected typhoidal Salmonella colonies were confirmed by biochemical tests as S. typhi or S. paratyphi A, before antimicrobial susceptibility test was done using Kirby-Bauer disk diffusion method. Diameters of zone of inhibitions were recorded and interpreted according to Clinical Laboratory Standards Institute guidelines. The data and results obtained were represented on tables and charts. Chi-square analysis was also used to determine statistical association among parameters and p-values ≤ 0.050 were considered significant. Results: Thirty-two (32) typhoidal Salmonella were isolated; 25 were S. typhi and seven S. paratyphi A. Thirty isolates came from patients while two were isolated among healthy individuals. High antibiotic resistance was observed with Augmentin (100%), Ceftazidime (87.5%), Cefuroxime (84.4%), Cefixime (84.4%) and Gentamicin (40.6%), while Ciprofloxacin (12.5%), Nitrofurantoin (12.5%) and Oflaxacin (18.8%) showed a lower resistance. Age, marital status and state of origin were socio demographic factors found to be associated with the antibiotic resistance. Also, frequency of infection, presenting symptoms and sampling duration were statistically associated with the antibiotic resistance. Conclusion: Multi-drug resistance, high antibiotic resistance of typhoidal Salmonella and factors associated with it in this study, should awaken public health concerns in curbing the excesses of typhoidal Salmonella.

A retrospective analysis of antimicrobial resistance in pathogenic Escherichia coli and Salmonella spp. isolates from poultry in Uganda

ABSTRACT There are increasing reports of antimicrobial treatment failures for bacterial diseases of poultry in Uganda. The paucity of data on antimicrobial resistance (AMR) of pathogenic bacteria in Uganda is a major setback to AMR control. This study investigated the occurrence of fowl typhoid, colibacillosis, and AMR in associated pathogens from 2012 to 2018. Laboratory records from the Central Diagnostic Laboratory (CDL), a National Veterinary Diagnostic Facility located at Makerere University, were reviewed. Archived isolates of the causative bacteria for the two diseases were also evaluated for AMR. The frequencies of the two disease conditions, their clinical and necropsy presentations and the demographic data of the diagnostic samples were summarized from the records. Archived bacterial isolates were revived before antimicrobial susceptibility testing. This was done on Mueller Hinton agar using the disk diffusion method, against 16 antimicrobials of medical and veterinary importance according to the Clinical Laboratory Standards Institute guidelines. A total of 697 poultry cases were presented for bacteriological investigations in the review period. Colibacillosis and salmonellosis had prevalence rates of 39.7% (277/697) and 16.2% (113/697), respectively. A total of 63 and 92 isolates of Escherichia coli and Salmonella spp., respectively, were archived but 43 (68.3%) E. coli and 47 (51.1%) Salmonella spp. isolates were recovered and evaluated for AMR. Multidrug resistance was more frequent in E. coli (38; 88.4%) than salmonellae (25; 53.2%), (p < 0.001). The high prevalence of colibacillosis, salmonellosis and the AMR of associated pathogens warrants immediate institution of appropriate disease control measures.

A hospital-based descriptive cross-sectional study in Eastern India to estimate the effect of nitrofurantoin, an age-old therapeutic option, in uncomplicated urinary tract infection

Background: Urinary pathogens develop lesser resistance against Nitrofurantoin than other antimicrobials such as Fluoroquinolones, Cotrimoxazole, and Carbapenems. Aim and Objective: The objective of this study was to estimate the sensitivity pattern of the urinary isolates against Nitrofurantoin in uncomplicated Urinary tract infection (UTI). Materials and Methods: The descriptive cross-sectional study was performed from January 1, 2020, to June 30, 2020, with 759 cases with signs and symptoms of uncomplicated UTI. Aseptically collected midstream urine was inoculated on Nutrient Agar Media, MacConkey’s Agar media, and Blood Agar media for bacterial isolation. Antimicrobial susceptibility testing was done by disk diffusion technique on Mueller Hinton Agar (Kirby Bauer technique) as per Clinical Laboratory Standards Institute guidelines. Results: Out of total of 759 urine samples, in 165 cases bacterial pathogens were isolated (21.73%). Only 17 were resistant to Nitrofurantoin (10.30%) whereas resistance to Fluoroquinolone (Ciprofloxacin) was in 58 isolates (35.15%) and Cotrimoxazole, in 37 isolates (22.42%). Resistance against Carbapenem antibiotics (Imipenem and Meropenem) was found in 29 isolates (17.57%). All the Nitrofurantoin resistant isolates were Gram-negative. Majority of the Nitrofurantoin resistant isolates were Klebsiella pneumonia (8 out of 17, i.e, 47.05%). All Nitrofurantoin resistant isolates were sensitive to Colistin and Tigecycline. Five out of 17 Nitrofurantoin resistant isolates were sensitive to Meropenem and Imipenem (29.41%). The Fischer exact test reveals that Nitrofurantoin is effective against the isolates resistant to Fluoroquinolones, Cotrimoxazole, and Carbapenems. Conclusion: Nitrofurantoin, even today, remains a good choice for empirical therapy for uncomplicated UTI.

1439. High Rates of Drug Resistance in Escherichia coli from a Pilot Antimicrobial Resistance Surveillance System in Cambodia

BackgroundAntimicrobial resistance (AMR) is a major and growing global public health problem. The Cambodia Ministry of Health established a pilot laboratory-based AMR surveillance system for blood specimens in 2017. The objective of this study is to characterize AMR among pathogenic isolates from blood samples.MethodsA retrospective analysis was performed using one year of data from a pilot AMR Surveillance system in Cambodia. Four blood culture isolate pathogens were included: Escherichia coli, Klebsiella pneumoniae, Salmonella Typhi /Salmonella Paratyphi A and Staphylococcus aureus. Blood culture isolates that were referred from eleven sentinel sites were analyzed at the National Public Health Laboratory for identification. Antibiotic susceptibility testing (AST) was done using disk diffusion, minimum inhibitory concentration method following Clinical Laboratory Standard Institute (CLSI) guidelines.ResultsAmong 214 pathogenic isolates from blood samples, E.coli was the most common (56.1%), followed by Salmonella Typhi/Salmonella Paratyphi A (18.7%), Staphylococcus aureus (13.5%), and Klebsiella pneumoniae (11.7%). Methicillin Resistance Staphylococcus aureus (MRSA) was detected in half of the isolates. E.coli was resistant to ampicillin (94.4%), trimethoprim-sulfamethoxazole (84.5%), and ceftriaxone (79.2%). Salmonella Typhi was resistant to ampicillin (73.3%) and trimethoprim-sulfamethoxazole (60.0%) and Salmonella Paratyphi A were resistant to fluoroquinolones (91.7%). For last resort antibiotics, E.coli was resistant to carbapenem groups (3.2% for imipenem, 4.9% for meropenem, and 5.0% for ertapenem). Klebsiella pneumoniae was not resistant to any groups.Conclusion E.coli was found at high rates in blood samples and was resistant to common antibiotics used in Cambodia. These pilot data show the importance of establishing a national AMR surveillance system in Cambodia to monitor AMR trends following GLASS guidelines.Disclosures All Authors: No reported disclosures

Prevalence and Antibiogram of Salmonella Species Isolated from Snail (Archachatina marginata) Sold in Port Harcourt, Rivers State, Nigeria

Increase in microbial population especially Salmonella species in food due to improper handling, storage and exposure to contaminants can raise public health concerns when consumed without adequate processing. This study evaluates the prevalence and antibiogram of Salmonella species associated with the giant land Snail (Archachatina marginata) sold in markets around Port Harcourt metropolis. A total number of seventy two (72) samples of land snail were collected from three markets; Creek Road, Mile one and Rumuokoro. The samples were labelled and transported in an ice packed coolers to the laboratory for analyses. Standard microbiological protocols were employed to determine the microbial load and species of the various parts (intestine, meat and fluid) of the snail samples after shucking. Antibiotics sensitivity profile testing of the isolated and identified Salmonella species were carried out as recommended by Clinical Laboratory Standard Institute (CLSI) and statistical analyses using one way ANOVA and all pairs Turkey-Kramer. Results from the study showed that the highest total heterotrophic bacteria count (THBC) of 8.6x106CFU/g was obtained in the snail intestine sourced from Creek road market while THBCs of 8.2x106 CFU/g and 7.3x106 CFU/g were from Mile one and Rumuokoro markets respectively. THBCs of meat from the markets ranged from 4.3-5.4x106 CFU/g and 3.7-4.9x106CFU/ml in fluid with Rumuokoro having the least occurrence respectively. Mean Salmonella counts (MSCs) ranged from 0.4-3.6 x103 CFU/g, with least count obtained from Rumuokoro and Mile 1 markets. Similarly, least MSCs in fluid and intestine were obtained from Rumuokoro and Mile 1 whereas Creek road Market had the highest respectively. Three species of Salmonella; S. arizonae, S. gallinarum and S. typhi were predominant in addition to other species such as Vibrio spp,, Bacillus spp., Staphylococcus spp., Shigella spp., Pseudomonas spp., Enterobacter spp., E. coli, Micrococcus spp., Acinetobacter spp., Klebsiella spp. and Listeria spp identified using both conventional and molecular method. Antibiogram profile revealed that all the identified Salmonella species were susceptible to Ofloxacin and Ciprofloxacin but strongly resistance to Cetazidime and Gentamicin. The diversity and elevated microbial load observed from this study calls for caution in handling and processing of snails since most of these bacteria may become aetiologic agents of several food-borne diseases and other pathological conditions. As a necessity, good quality control measures and proper chemotherapy should be administered to patients with signs and symptoms of food borne illness emanating from consumption of snail.