Antibiotic Susceptibility Studies Research Articles

Sepsis treatment options identified by 10-year study of microbial isolates and antibiotic susceptibility in a level-four neonatal intensive care unit.

This observational study investigated the microbiology of blood culture-positive sepsis episodes and susceptibility to empiric antibiotics in early-onset sepsis (EOS) and late-onset sepsis (LOS) in a level-four neonatal intensive care unit (NICU) from 2010 to 2019. It was based on patient records and data that Oslo University Hospital, Norway, routinely submitted to the Norwegian Neonatal Network database. Clinical data were merged with blood culture results, including antibiotic susceptibility. We studied 5249 infants admitted to the NICU 6321 times and identified 324 positive blood cultures from 287 infants, with 30 EOS and 305 LOS episodes. Frequent causative agents for EOS were group B streptococci (33.3%), Escherichia coli (20.0%) and Staphylococcus aureus (16.7%). All were susceptible to empiric ampicillin and gentamicin. LOS was most frequently caused by coagulase-negative staphylococci (CONS) (73.8%), Staphylococcus aureus (15.7%) and Enterococci (6.9%). CONS, Staphylococcus aureus, Enterococci, Escherichia coli, Klebsiella and Enterobacter represented 91.9% of LOS episodes and were susceptible to vancomycin and cefotaxime (96.1%), vancomycin and gentamicin (97.0%) and cloxacillin and gentamicin (38.1%). Empiric treatment with ampicillin and gentamicin was adequate for EOS. Combining vancomycin and gentamicin may be a safer alternative to cefotaxime for LOS, as this reduces exposure to broad-spectrum antibiotics.

OROPHARYNGEAL MICROBIOTA IN CHILDREN WITH WEB INFECTION ON THE BACKGROUND OF ANTIBIOTIC THERAPY

According to statistics from the World Health Organization, infectious mononucleosis caused by Epstein-Barr virus affects 90% of the world's population. The aim of this study was to study the composition of the oropharyngeal microbiota and to determine the antibiotic sensitivity of its representatives, which are released in clinically significant concentrations from children with WEB infection who received antibiotic therapy. 28 patients with WEB infection in children aged 5 to 16 years were examined. Among the 28 children in inpatient treatment, 78.6% were patients under the age of 10. All children received antibiotic therapy, although according to treatment protocols, it is indicated only in the case of a bacterial infection.
 Streptococcus spp. with β-hemolysis (64.3%). Detection of S. aureus in 35.7% of patients indicates a violation of the structure of the normal microbiocenosis of the oropharynx. The study of antibiotic susceptibility of staphylococci and streptococci showed the presence of resistance in 52.6% of isolated strains of streptococci and 25.0% of staphylococci to azithromycin.

Factors for production growth at poultry enterprises in Russia

The article presents the results of a study of antibiotic resistance and antibiotic susceptibility of 96 isolates of bacteria of the genus Salmonella, which were isolated from various poultry enterprises of the Russian Federation during 2020, to various antibacterial drugs. Thus, 100% of the examined Salmonella cultures turned out to be completely resistant to cefixime, fusidic acid, lincomycin, linezolid, metronidazole, nafcillin, oleandomycinum, oxacillin, benzylpenicillin, pristinamycine, rifampicin, tylosin, bacitracin, erythromycin, ceftazidime. Most Salmonella isolates showed resistance against clarithromycin, spiramycin, cefepime, cefoperazone, doripenem, sulfadiazine and cefpirome - 90.6%; cefotaxime - 87.5%; pefloxacin, cefdinir, clindamycin, clindamycin, neomycin, piperacillin, lomefloxacin, moxifloxacin, streptomycin, cefazolin, kanamycin, azithromycin, sisomicin, furadonin, doxycycline, cefaclor, furagin, tetracycline, oxytetracycline, polymyxin-B, spectinomycin, gentamicin and other types of drugs. At the same time, salmonella showed high susceptibility to: amoxiclav (88.8%); fosfomycin and trimetroprim (80.2%); ofloxacin (76.0%); cephalexin and enrofloxacin (71.9%); co-trimoxazole (67.7%); cefotaxime / clavulanic acid, sulfafurazole, sulfametizole (59.4%); ciprofloxacin (58.3%) and others. Thus, the study established a wide spread of multi-resistant Salmonella cultures in poultry enterprises of the Russian Federation.

A Retrospective Study of Bacteriology and Antibiotic Sensitivity Pattern of Post Operative Surgical Site Infections in Orthopedics

Surgical Site infection (SSI) is one of the most common post-operative complications and causes significant post-operative morbidity and mortality. The global estimates of SSI have varied from 0.5% to 15%, studies in India have consistently shown higher rates ranging from 23% to 38%1. The aim of the study was to know the etiological bacterial agents causing SSI and their antimicrobial susceptibility pattern. This retrospective study included 69 patients who developed Post-operative wound infections (SSI) during the 1-year period from April 2019 to March 2020. An analysis of SSI occurrence, the organisms isolated and antibiotic sensitivity pattern results was made. In overall surgeries conducted during the study period in orthopedics department at our institute, 69 cases were clinically diagnosed of having SSIs, including 51 males and 18 females with the mean age of 39.2 years. Out of the total 69 samples, 6 (8.69%) yielded no bacterial growth and among the rest 63 samples, Staphylococcus aureus 21 (30.43%) was the most common organism isolated. The other organisms isolated were Klebsiella pneumonia 13 (18.84%), Pseudomonas 11 (15.94%), Escherichia coli 5 (7.24%), Proteus species 3 (4.34%) and Acinetobacter species 3 (4.34%). Mixed isolates were obtained in 2 (11.9%) specimens. Bacteriological and antibiotic susceptibility study is an important tool to treat infection timely and effectively in-turn minimizing untoward long term sequelae of surgical site infections.

Antibiotic susceptibility and fosfomycin resistance characterization in a cohort of children older than 6 years of age with urinary tract infection

Fosfomycin tromethamol (FT) was reintroduced as an option for the treatment of low urinary tract infection (UTI) in children. In this study, we described the antibiotic sensitivity and mechanisms of resistance to fosfomycin in isolates from children older than 6 years with UTI. Urine culture and antibiotic susceptibility study were performed. In fosfomycin resistant strains, PCR for fos, blaCTX-M was performed followed by classification by phylogenetic group and sequencetyping. Escherichia coli was the most frequent etiological agent (89.2%). The susceptibility percentages were: fosfomycin 97.9%; amoxicillin-clavulanate 92.7%; cefuroxime and ceftriaxone 99%; nitrofurantoin 94.4%. An E. coli strain (ST69, phylogenetic group D) was resistant to fosfomycin (MIC 256mg/l) and carried the blaCTX-M-14 and fosA3 genes in a 45kb IncN-type plasmid. This is the first report of E. coli ST69 with blaCTX-M-14/fosA3 of human origin.

Surveillance of disease incidence in shrimp farms located in the east coastal region of India and in vitro antibacterial efficacy of probiotics against Vibrio parahaemolyticus

We surveyed 130 shrimp farms located on the eastern coast of India to determine the prevalence of emerging diseases in Litopenaeus vannamei and Penaeus monodon. Live shrimps were collected from the farms based on external symptoms. The biochemical, molecular, and histopathology results confirmed infection with Enterocytozoon hepatopenaei (32.4%), Vibrio parahaemolyticus (27.7%), White Spot Syndrome Virus (25.4%), Vibrio alginolyticus (16.1%), Vibrio harveyi (13.1%), Monodon-type baculovirus (4.61%), and infectious Hematopoietic Necrosis Virus (2.3%) in the collected shrimps. Enterocytozoon hepatopenaei (EHP) occurred more frequently in L. vannamei than P. monodon, with the microsporidian spores in the hepatopancreas. In P. monodon, Monodon-type Baculovirus infection (33.3%) was dominant and small percentages of WSSV, IHHNV, V. alginolyticus, and V. harveyi were observed. A few ponds were observed with co-infection of EHP and WSSV (7.6%), V. parahaemolyticus and WSSV (4.6%) and also V. parahaemolyticus and EHP (6.1%). Among the Vibrio spp, V. parahaemolyticus showed the highest percentage of infection in L. vannamei. Overall, we found that shrimp were chiefly infected with EHP and V. parahaemolyticus. The impact of water quality parameters on shrimp diseases was not addressed in this study. In an antibiotic susceptibility study, V. parahaemolyticus isolated from L. vannamei ponds was susceptible to nitrofurantoin, chloramphenicol, oxytetracycline and tetracycline, but resistant to erythromycin and nalidixic acid. In a preliminary in vitro antibacterial activity assay, probiotics against V. parahaemolyticus showed high inhibitory activity and the results encourage further in-depth studies on the efficacy of probiotics for disease control and prevention in shrimp farms.

Multidrug resistance to commonly prescribed antibiotics in Escherichia coli isolated from barbecued beef (Suya) sold in a Nigerian City.

IntroductionSuya, a form of barbecued meat widely consumed in Nigeria is a rising source of concern for the dissemination of pathogens and antibiotic resistance.Methodsthis study was carried out to determine the antibiotic resistance profile of Escherichia coli (E. coli) isolated from Suya sold in Karu Local Government Area, Nasarawa State, Nigeria. A total of three hundred (300) Suya samples were collected and screened for the presence of E. coli. An antibiotic susceptibility study was carried out on the isolated bacteria to determine their resistance profiles.Resultsthe overall isolation and occurrence of E. coli was 13.3%. The isolated organisms were most resistant to Ampicillin (100%) followed by Amoxicillin/Clavulanic acid (95%), Ciprofloxacin (92.5%), Nitrofurantoin, Imipenem and Ceftriaxone (85%), Cefixime (80%), Streptomycin (77.5%), and Cotrimoxazole (77%), with a low level of resistance recorded against Gentamycin (5%). Most of the E. coli isolates had multiple resistance (MAR) to at least five antibiotics (MAR Index of = 0.5) and the most frequent MAR Index was 0.8 with 37.5% occurrence. The most frequently encountered resistance phenotype was Nitrofurantoin-Imipenem-Streptomycin-Ciprofloxacin-Ceftriaxone-Amoxicillin/clavulanic acid-Cefixime-Ampicillin. The E. coli isolates categorised based on drug resistance classes were Multi-Drug Resistance, MDR (97.5%), Pan Drug Resistance, PDR (2.5%), Non-Multi-Drug Resistance, NMDR (0.0%) and Extensive Drug Resistance, XDR (0.0%).Conclusionthese findings indicate a potential danger of multidrug resistant organisms in circulation. Antibiotics stewardship and drug resistance surveillance is strongly recommended for all stakeholders

Method for concentrating viable microorganisms for microbial load determination and eliminating uncertainty from matrix effects from urine and whole blood

The ability to assess and eliminate the matrix effect in bioanalytical methods is critical for reproducibility, but sample preparation procedures necessary to address the matrix effect for microbiological methods could be significantly different if viable pathogens are required for downstream microbiological response analysis. A pure bacterial culture remains essential for virulence, antibiotic susceptibility, and phenotypic response studies in order to facilitate the understanding and treatment of caused diseases. Bacterial culture involves the collection, inoculation, incubation, growth, and detection of viable organisms while avoiding contamination throughout the entire process. The goal of this method is to concentrate viable pathogens directly from clinical specimens such as whole blood and urine while removing most interfering matrix components through pelleting in an enriched media, which is designed to facilitate the growth of clinically relevant microorganisms. Nonselective culture media with no inhibitors is used to permit the growth of most of the microorganisms present in the clinical samples studied. Most of the species implicated in clinical infections are mesophilic bacterial species, so the pelleting procedure is conducted at medium temperatures of 37°C to facilitate optimal growth.•Viable bacterial pelleting for phenotypic response analysis.•Concentration of bacteria by centrifugation and matrix component removal for direct-from-specimen molecular analysis.•Viable pathogen recovery directly from whole blood and urine.

Molecular characterization of Staphylococcus aureus isolated from hospital acquired sepsis in pediatrics, relation to antibiotics, resistance and virulence genes.

The objective of this study was to determine the prevalence of antibiotic resistance genes mecA, vanA, B, C and virulence genes Panton-Valentine Leucocidin (PVL) and fibronectin-binding protein (fnBPA) among S. aureus isolates from hospital-acquired sepsis from pediatric intensive care units. The study was a retrospective cross-sectional study, including 250 unique isolates of S. aureus obtained from pediatric patients with hospital-acquired sepsis. The isolates were subjected to study of antibiotic susceptibility by disc diffusion method and molecular analysis of antibiotic resistance genes and certain virulence genes (PVL and fnBPA genes). Methicillin resistant S. aureus represented 178 (71%) of the isolated S. aureus and reduced susceptibility to vancomycin was detected by minimum inhibitory concentration in 39 (22%) isolates. It was found that there was a strong association between the MRSA strains and resistance to some antibiotics, devices association (p<0.001) and patient outcomes (p=0.003). There was a significant association between reduced vancomycin susceptibility (p=0.010), the presence of a central line catheter (p=0.000) and fnBPA gene (p<0.001) and mortality rate. The present study highlights that major S. aureus strains isolated from sepsis in pediatric patients were methicillin resistant with a substantial proportion of reduced susceptibility to vancomycin. Although none of the isolates had van genes responsible for vancomycin resistance, this finding warrants a considerable attention for study as it was a risk factor for mortality in those patients. The virulence genes fibronectin-binding protein and Panton-Valentine Leucocidin were not uncommon in S. aureus.

Study of Antibiotic Susceptibility among Bacterial Isolates in Neonatal Intensive Care Unit of a Tertiary Care Hospital: A Descriptive Cross-sectional Study.

Neonatal sepsis is a major cause of neonatal morbidity and mortality worldwide, especially in developing countries like Nepal. Antibiotic resistance among microorganisms poses new challenges in the treatment of neonatal sepsis. The present study is conducted with the objectives of determining clinico-bacteriological profile and antibiotic susceptibility among isolated bacteria in a neonatal intensive care unit. A descriptive cross-sectional study was conducted from January 1, 2017, to December 31, 2019, in the neonatal intensive care unit of a tertiary care hospital after obtaining ethical clearance from Institutional Review Committee (Reference Number: 2020-064). The sample size was calculated and 77 neonates with culture-proven sepsis were included in the study. The antibiotic susceptibility tests of the isolates were done by Kirby-Bauer disc diffusion method. Data entry was done in Statistical Packages for the Social Sciences version 20. Of the 841 specimens (blood, cerebrospinal fluid, urine, tracheal aspirate and pus) processed for culture, bacteria were isolated in 84 (10.0%) specimens. Among the 84, gram-negative bacilli were the predominant isolates 76 (90.5%); of which Acinetobacter baumannii was the most common 27 (32.1%). Both the Gram-negative and the Gram-positive bacteria showed high resistance to Penicillin and Cephalosporins. Gram-negative bacteria showed maximum sensitivity to Colistin, Carbapenems, Tigecycline and Fluoroquinolones. Gram-positive bacteria showed maximum susceptibility to Amikacin, Vancomycin and Carbapenems. Judicious use of antibiotics based on the updated knowledge of prevalent organisms in the local hospital setting and their antibiotic sensitivity pattern is of utmost importance for the effective treatment of neonatal sepsis.

Characteristics and dynamics of Salmonella diversity and prevalence of biomarker genes in Port Blair Bays, South Andaman, India

Salmonella is a major cause of morbidity and mortality in humans worldwide, and the infection with multidrug-resistant strains can cause severe diseases. Many coastal cities around the world discharge their wastewaters into the marine environment. These wastewaters contain a variety of pathogenic microorganisms that may have a role in the contamination of this ecosystem and have potential risks for public health. Using an environmental approach, the present study investigated the presence of Salmonella in sediment and water samples collected from Port Blair Bays. In this environmental approach, the provided information about the diversity of the Salmonella serovars, antibiotic resistance and the prevalence of virulence factors in Salmonella, especially from the coastal waters of Port Blair Bays. The occurrence of Salmonellae was significantly higher in water column samples (2.9%) than in those taken from the marine sediments (0.7%). Of the 133 positive Salmonella strains, 22 different serovars were identified. Salmonella enterica serovar Senftenberg was the predominant serovar, being represented by 54 isolates (42.5%), followed by serovar Typhimurium (19 isolates [15%]) and serovar Agona (12 isolates [9.4%]). The presence of virulence genes (filC, sitC, hilA, invA, sipC, hilD, hilC, invF, invE, invH, sipF, aadA, pare, gyrA, spaP and parC) and susceptibility studies with 10 selected antibiotics were also performed. The results of this study revealed that all Salmonella isolates were positive for targeted virulence genes and were resistant to at least one antibiotic. Antibiotic susceptibility studies revealed the presence of multidrug resistant Salmonella strains in coastal water, which usually from land base sources end up in the marine environment and may pose a significant risk on public health.

Screening for urinary tract infection-causing Klebsiella pneumoniae using CHROMagar

Introduction. Urinary tract infections (UTIs) are considered prevalent among humans. While Klebsiella pneumoniae and Escherichia coli are commonly isolated from patients with UTIs, K. pneumoniae is more frequently isolated from specimens isolated from hospital-acquired infections. Aim. The current study aimed to characterise and evaluate pathogenic K. pneumoniae isolated from patients suspected with a UTI at King Abdulaziz University Hospital. Methodology. Twenty-four urine samples obtained from patients, between 12 November 2018 and 11 January 2019, were included in the study, and the microbial content was analysed via urine culture and VITEK 2 analyses. Results. Of the 24 urine specimens, 23 samples (95.8%) yielded significant microbial growth (&gt; 105 CFU/mL K. pneumoniae), and one sample (4.2%) yielded non-pathogenic microbial growth (&lt; 105 CFU/mL K. pneumoniae). Of the specimens with cell counts of &gt;105 CFU/mL, 21 samples (87.5%) were pure cultures showing the growth of a single pathogen, and three samples (12.5%) were mixed cultures, showing the growth of two or more pathogens; 10 (41.7%) samples were extended-spectrum beta-lactamase (ESBL) producers. VITEK 2 analysis showed that the most effective antibiotic was piperacillin, with 87.5% of the strains isolated in this study showing sensitivity to it, followed by gentamicin (83.3%) and ciprofloxacin (79.2%). Antibiotic susceptibility studies identified resistance against ampicillin (45.83%), trimethoprim (41.67%), and amoxicillin (25%) in the study isolates. Differential chromogenic culture media CHROMagar ESBL and CHROMagar KPC (K. pneumoniae carbapenemase) were used for rapid screening of ESBL and KPC producers. Among the 24 K. pneumoniae isolates, six isolates (25%) formed metallic blue colonies on CHROMagar ESBL, five (20.3%) were inhibited, and nine (37.5%) showed weak pigmentation. Three isolates (12.5%) formed pink colonies on CHROMagar ESBL. Seventeen isolates (70.8%) were KPC-positive, four (16.7%) showed weak pigmentation, and three (12.5%) formed pink colonies on CHROMagar KPC. The results from CHROMagar cultures agreed with those of VITEK 2 analyses. Conclusion. Various microbial detection methods have been used in medical microbiology laboratories to identify and screen for microbial resistance in clinical specimens. VITEK 2 and CHROMagar are amongst the commonly used methods. Here, we report a possible discrepancy between the detection techniques and that the data obtained by different methods need not be synergistic. However, the use of a chromogenic medium offers a quick and accurate method for detection, enumeration, and presumptive identification of urinary tract pathogens.

Identification and Characterization of Planktonic Biofilm-Like Aggregates in Infected Synovial Fluids From Joint Infections.

Recent in vitro studies reported the exceptional ability of some bacterial species to form biofilm-like aggregates in human and animal synovial fluids (SF), but evidences from infected clinical samples are still lacking. In this study, we investigated whether this bacterial phenotype was present in infected SFs collected from joint infections and if it was maintained in in vitro settings. SFs sent for culture to the Laboratory of Microbiology of our institute were directly analyzed by means of confocal laser scanning microscopy (CLSM), and the infective agents were isolated for further in vitro tests. Moreover, sterile SF was collected from patients who did not receive previous antibiotic therapy to investigate the formation of bacterial aggregates, together with biofilm and matrix production on a titanium surface. Finally, antibiotic susceptibility studies were performed by using bovine SF. Four Staphylococcus aureus, one Staphylococcus lugdunensis, and one Prevotella bivia strain were identified in the infected SFs. The CLSM analysis showed that all staphylococci were present as a mixture of single cells and bacterial clumps surrounded by an exopolymeric substance, which comprised SF-derived fibrin, while all P. bivia cells appeared separated. Despite that, differences in the ability to aggregate between S. aureus and S. lugdunensis were observed in clinical SFs. These different phenotypes were further confirmed by in vitro growth, even though the application of such ex vivo approach lead all staphylococci to form exceptionally large microbial aggregates, which are several folds bigger than those observed in clinical samples. Planktonic aggregates challenged for antibiotic susceptibility revealed a sharp increase of recalcitrance to the treatments. Although this is still at a preliminary stage, the present work confirmed the ability of staphylococci to form free-floating biofilm-like aggregates in infected SF from patients with joint infections. Furthermore, the obtained results pointed out that future in vitro research on joint infections will benefit from the use of human- or animal-derived SF. Even though this approach should be carefully validated in further studies comprising a larger microbial population, these findings pose new challenges in the treatment of infected native and prosthetic joints and for the approach to new investigations.

Marked Presence of Methicillin-Resistant Staphylococcus aureus in Wild Lagomorphs in Valencia, Spain.

Simple SummaryThe presence of bacteria resistant to antibiotics, such as Staphylococcus aureus resistant to methicillin (MRSA), is becoming an increasing everyday concern for their implications for human and animal health. This is even more alarming when such bacteria are isolated in wild animals which, in principle, should not come into contact with antibiotics. This work studied 353 rabbits and 10 hares hunted in rabbit high-density areas. Of these, 41.3% carried S. aureus in some sampled locations, of which 63.3% were MRSA. These are surprising results given the unexpected high presence of MRSA in the studied animals. This finding is very worrying because these animals tend to enter the food chain with no veterinary control, which implies a risk for human health. Thus it is necessary to extend this study to other, less-populated areas with other animal species (ruminants, rabbit predators, hunting dogs, etc.) or even water sources to obtain further knowledge about the origin of bacterial resistances in nature.The appearance of methicillin-resistant strains of Staphylococcus aureus (MRSA) in several animal species (including rabbits) has set off alarms for their capacity to act as reservoirs for this bacterium. This is especially important in wild animals given its epidemiological implications. The objectives of this study were to identify and characterize S. aureus, specifically MRSA, strains in wild lagomorph high-density areas. Ten hares and 353 wild rabbits from 14 towns with a high rabbit density in the Valencian region (eastern Spanish coast) were sampled. Swabs from the nasal cavity, ears, perineum and lesions (when present) were taken for microbiological studies. The detection of different genes and antibiotic susceptibility studies were also carried out. Of all the animals, 41.3% were positive for S. aureus, of which 63.3% were MRSA. Ears were the anatomical location with more S. aureus and MRSA strains. The more frequently identified MLST type was ST1945 (97.1%, 136/140). The mecA gene was found only in one sample. The rest (n = 139) carried the mecC gene and were included in CC130, except one. Penicillin resistance was detected in 28 mec-negative isolates and, in one case, bacitracin resistance. mecA isolate presented resistance to enrofloxacin and tetracycline, and 10 mecC isolates also showed bacitracin resistance. No MRSA isolate was positive for genes chp, sea, tst and PVL. Two ST1945 isolates contained IEC type E (comprising genes scn and sak). mecA-isolate was positive for blaZ. Of the 28 MSSA strains showing resistance to penicillin, 22 carried the blaZ gene. These surprising results highlight the marked presence of MRSA strains in wild rabbits in high-density areas.

Detection of bacterial pathogens causing a chronic suppurative otits media and study of antibiotic susceptibility in Iraqi patients

A complete number of 100 ear swabs were researched for the present study. This investigation is to discover the microbiological profile and their anti-microbial affectability designs in patients with constant suppurative otitis media in an Al-hububi clinic. Gram recoloring, direct microscopy with KOH, culture affectability and biochemical tests were completed to distinguish the living beings and to realize the affectability design. Every one of the swabs were gathered from patients with the clinical conclusion of unending suppurative otitis media. Pseudomonas aeruginosa (37.21%) was generally secluded life form pursued by Staphylococcus aureus (27.91%) from the samples. Amikacin was found to be the most effective antibiotic with low resistance rate. The investigation of microbial example and their anti-infection affectability decides the predominant living beings causing unending suppurative otitis media in neighborhood begins fitting treatment of otitis media and its intricacies for effective result.

Study of Clinical profile and Antibiotic susceptibility of Urinary Tract Infection in a Tertiary Care Hospital

Study of Clinical profile and Antibiotic susceptibility of Urinary Tract Infection in a Tertiary Care Hospital

New insights into resistance of Helicobacter pylori against third- and fourth-generation fluoroquinolones: A molecular docking study of prevalent GyrA mutations.

Fluoroquinolones hinder bacterial DNA replication by inhibiting DNA gyrase. However, mutations, in the QRDR segment of its A subunit (GyrA), cause antibiotic resistance. Here, the interactions of levofloxacin (LVX), gemifloxacin (GXN), and moxifloxacin (MXN) with Helicobacter pylori GyrA, in LVX-resistant vs -sensitive strains, were studied. Levoflixacin-sensitive (n=4) and -resistant (n=9) Hpylori strains, randomly selected from another antibiotic susceptibility study, underwent PCR amplification of gyrA gene, spanning the QRDR segment. The amplified gene fragments were sequenced and aligned. The homology model of Hpylori GyrA was built based on that of Escherichia coli, and energy minimization was done. The interaction patterns of LVX, GXN, and MXN with GyrA were analyzed via molecular docking studies. Sequence alignment of the 13 studied strains, created 5 categories of strains: (A) wild type-like (H pylori ATCC26695), (B) N87K-only, (C) D91N-only, (D) N87K+V94L, and (E) D91N+A97V mutations. The minimum inhibitory concentrations (MIC) for LVX-sensitive (category A) and -resistant (categories B-E) strains were <1mg/L and ≥32mg/L, respectively. The binding mode of GyrA in category A with LVX identified G35/N87/Y90/D91/V94/G114/S115/I116/D117/G118/D119, as key residues, some residing outside the QRDR segment. Category B strains lost only one interaction (G35), which led to elevated binding free energy (∆G) and full LVX resistance. Categories C-E lost more contacts, with higher ∆G and again full LVX resistance. GXN bound to GyrA of categories A and B via a different set of key residues, while MXN retained the lost contact (G35) in LVX-resistant, category B strains. Using molecular docking tools, we identified the key residues responsible for interaction of GyrA with LVX, GXN, and MXN. In the presence of N87K-only mutation, the loss of one of these contacts (ie, G35) led to full LVX resistance. Yet, GXN and MXN overcame this mutation, by retaining all key contacts with GyrA.

Le profil bactériologique des pleurésies purulentes au CHU de Marrakech

Prognosis of purulent pleurisy remains severe especially in children despite antibiotic therapy. The bacteriological diagnosis is essential to confirm the diagnosis, adapt antibiotic therapy and guide the etiology. The objective of the study is to identify the bacteria involved in pleural puncture samples and evaluate antibiotic susceptibility among patients hospitalized at the different services at the University Hospital of Marrakech. It is a retrospective study of 6 years (2012-2017), including all pleural puncture (LP) samples taken in clinical care at beds of patients, received at the laboratory and from patients hospitalized at the different services at the University Hospital Center of Marrakesh. Out of 733 Purulent pleurisy completed, 98 were positive (13,3 %). The average age was 30 years old. The bacteriological profile was dominated by gram-positive bacteria (63,2 %). among them, Streptococcus pneumoniae (16,4 %), followed by Staphylococcus aureus (15,4 %), coagulase-negative Staphylococcus (SCN) (11,2 %), Streptococcus spp (14,1 %), Streptococcus haemolytic Group A (5,1 %) and Enterococcus spp (1 %). Enterobacteria accounted for 20,5 %. Pseudomonas aeuroginosa was found in 8,3 % of cases. The documented pleurisy came mainly from the pneumology department (20.5 %) pediatric department (18 %) and the infectious diseases department (11,6 %). The study of antibiotic susceptibility of isolated strains revealed penicillin sensitivity of 68.75 % in Streptococcus pneumoniae isolates. All strains of Staphylococcus aureus were sensitive to meticillin. In Enterobacteria, resistance to C3G was 35 %.The prevention of purulent pleurisy would consist of good management of otorhinolaryngology infections, broncho-pulmonary infections and pneumococcal vaccination of subjects at risk.

The Bacteriological Profile of Otorhinolaryngological Infections

Otorhinolaryngological infections are common pathologies especially in children, their clinical manifestations are varied. Knowledge of the microbial ecology of these infections in the ENT sphere may be important for the choice of probabilistic antibiotic therapy, but also for adapting and adjusting the treatment in therapeutic failure situations and complications. This is a descriptive retrospective study between January 2017 and August 2018. Including all samples taken in the ENT field in patients hospitalized in the ORL service of Med VI University Hospital of Marrakech. Of the 115 samples, bacterial confirmation was found in 87% of cases. The bacteriological profile was dominated by Gram-positive bacteria in 52% of cases. Isolated strains were mainly represented by Streptococcus (28%), followed by Staphylococcus aureus (22%). Enterobacteria accounted for 34% of isolates dominated by Klebsiella pneumoniae found in 20.5% of cases. The study of antibiotic susceptibility of isolated strains revealed a penicillin sensitivity of 98% in isolates of Streptococcus pneumoniae. A 75% sensitivity to amoxicillin was revealed in Enterococcus and all strains of Staphylococcus aureus were sensitive to meticillin. In enterobacteria, resistance to C3G was 18%, 38% to fluoroquinolones, 35% to cotrimoxazole and 29% of strains were resistant to Gentamycin. The multi-resistant strains of Pseudomonas aeruginosa were found in 8% of cases.

Antibacterial effect of copper sulfate against multi-drug resistant nosocomial pathogens isolated from clinical samples.

Background and Objective:With the emergence of antibiotic resistance and the hospital acquired infection, the interest for antimicrobial agents has recently increased again in public health. Copper is recommended as a supplementary method of increasing biological safety in the hospital environment. The objective of this study was to determine the antibacterial activity of copper sulfate salts on strains of bacterial pathogens isolated from different clinical pictures in different health establishment in Algeria.Methods:A total of 25 different bacterial isolates (16 Enterobacteriaceae, 5 Staphylococci, and 4 Pseudomonas) were tested for susceptibility to copper sulfate using minimum inhibitory concentration (MIC-Cu) and minimum bactericidal concentrations (MBC-Cu) determinations. All isolates were also tested for susceptibility to six antibiotics.Results:Antibiotic susceptibility studies revealed that 100% of isolates were resistant to one or more antibiotics. Fifty two percent of isolates were very susceptible to copper sulfate, with MICs ranging from 100 to 200 µg/ml. MBC-Cu = 1600 μg/ml showed the best bactericidal effect against the great majority of studied bacteria (52%). A good bactericidal activities of copper sulfate were recorded against Proteus vulgaris and Staphylococcus aureus (MBC/MIC=1). The Gram-negative bacteria isolates which were copper resistant also showed a high resistance to chloramphenicol (r=0.78) and Trimethoprime (r=0.61). Furthermore, the strains that were no-susceptible to three different antimicrobial classes (Escherichia coli, Staphylococcus saprophyticus) were not resistant to copper sulfate.Conclusion:Copper sulfate salts has significant antibacterial activity against multi-drug resistant nosocomial pathogens.