Six-year analysis of key monitoring for bacterial strain distribution and antibiotic sensitivity in a hospital

BACKGROUND With the widespread use of antimicrobial drugs,bacterial resistance has become a significant problem,posing a serious threat to public health.The prevalence of clinical infection strains in hospitals and their drug sensitivities are key to the appropriate use of antibiotics in clinical practice.AIM To identify prevalent bacteria and their antibiotic resistance profiles in a hospital setting,thereby guiding effective antibiotic usage by clinicians.METHODS Specimens from across the institution were collected by the microbiology laboratory.The VITEK 2 compact fully automatic analyzer was used for bacterial identification and antibiotic sensitivity testing,and the WHONET5.6 software was utilized for statistical analysis.RESULTS A total of 12062 bacterial strains of key monitoring significance were detected.Staphylococcus aureus demonstrated widespread resistance to penicillin,but none of the strains were resistant to vancomycin or linezolid.Moreover,219 strains of methicillin-resistant coagulase-negative staphylococci and 110 strains of methicillin-resistant Staphylococcus aureus were detected.Enterococcus faecalis showed moderate resistance to the third-generation quinolones ciprofloxacin and levofloxacin,but its resistance to nitrofurantoin and tetracycline was low.Enterococcus faecium displayed significantly lower resistance to third-and fourthgeneration quinolones than Enterococcus faecalis.The resistance of two key monitoring strains,Escherichia coli and Klebsiella pneumoniae,to piperacillin/tazobactam was 5%-8%.However,none of the Escherichia coli and Klebsiella pneumoniae strains were resistant to meropenem.The resistance of Acinetobacter baumannii to piperacillin/sulbactam was nearly 90%.Nonetheless,the resistance to tigecycline was low,and Pseudomonas aeruginosa demonstrated minimal resistance in the antibiotic sensitivity test,maintaining a resistance of<10%to the cephalosporin antibiotics cefotetan and cefoperazone over the last 6 years.The resistance to amikacin remained at 0.2%over the past 3 years.CONCLUSION Our hospital’s overall antibiotic resistance rate was relatively stable from 2017 to 2022.The detection rates of key monitoring strains are reported quarterly and their resistance dynamics are monitored and communicated to the entire hospital,which can guide clinical antibiotic selection.

Ocular bacterial infections at a tertiary eye center in China: a 5-year review of pathogen distribution and antibiotic sensitivity

AIM: To provide statistical evidence for the use of antibiotics in ophthalmology by assessing the distribution and antibiotic sensitivity of bacterial isolates from ocular specimens with suspected microbial infections.METHODS: This study applied a retrospective analysis of 3690 bacterial isolates from ocular specimens, which were obtained from the conjunctiva, cornea, aqueous humor, vitreous body, and other ocular sites of the patients at Shandong Eye Institute in northern China from January 2013 to December 2017. The parameters assessed mainly included the distribution of isolated bacteria and the results of susceptibility tests for antibiotics. In the analysis of antibiotic sensitivities, the bacteria were divided into four groups according to gram staining, and statistical methods were used to compare their antibiotic sensitivities. RESULTS: Among the 3690 isolated bacterial strains, Staphylococcus epidermidis(2007, 54.39%) accounted for the highest proportion. As for the total isolates, their sensitivity rate to gatifloxacin was up to 90.01%, with four types of gram-stained bacteria being all highly sensitive to it, but their sensitivity rate to levofloxacin was only 51.91%. The sensitivity rate of gram-negative bacilli(G-B) to levofloxacin was 83.66%, significantly higher than the other three types of gram-stained bacteria(P<0.05). Gram-positive cocci (G+C, 97.95%) and gram-positive bacilli(G+B, 97.54%) were more sensitive to vancomycin than gram-negative cocci(G-C, 70.59%) and G-B(68.57%;P<0.05). For fusidic acid, the sensitivity rates of G+C(89.83%) and G+B(73.37%) were significantly higher than that of G-B(29.83%;P<0.05). The gram-negative bacteria's sensitivity rate to cefuroxime was as low as 59.25%, but only G-B was less sensitive to cefuroxime(57.28%), while G-C was still highly sensitive(89.29%). The sensitivity rate of gram-positive bacteria to moxifloxacin was as high as 80.28%, but only G+C was highly sensitive to moxifloxacin(81.21%), while G+B was still less sensitive(32.00%). CONCLUSION: Staphylococcus epidermidis is the predominant isolate in all ocular specimens with bacteria. Gatifloxacin is more suitable for topical prophylactic use than levofloxacin in ophthalmology when necessar y. Vancomycin and fusidic acid both have better effects on gram-positive bacteria than gram-negative bacteria. More accurate antibiotic sensitivity analysis results can be obtained when a more detailed bacterial classification and more appropriate statistical methods are performed.

Epidemiologic Profile Urinary Tract Infections: Experience of the Microbiology Laboratory of the University Hospital Mohamed VI in Tangier

Urinary tract infection is one of the most common bacterial infections in humans. The urine cytobacteriological examination is the key test for its diagnosis. This work aims to Evaluate the prevalence of urinary tract infection at the Microbiology Laboratory of the University Hospital Mohamed VI in Tangier and to highlight its epidemiological and bacteriological characteristics. It was a descriptive study with retrospective data collection which took place from January 2021 to June 2022, at the Microbiology Laboratory of the university hospital Mohamed VI in Tangier. It covered all urine cytobacteriological examinations (ECBU) during the study period. We identified 77 cases of urinary tract infections out of 300 requests for (ECBU), that is a positivity rate of 25 %. The mean age was 55 years. The male gender was predominant. The epidemiological profile of the isolated strains was dominated by Enterobacteriaceae 81 %, followed by Gram-positive cocci 11 % and non-fermenting gram-negative bacteria 8 %. The main bacteria responsible for urinary tract infections in order of frequency: Escherichia coli 42 %, Klebsiella pneumoniae 20 %, Enterobacter cloacae 9 %, Staphylococcus aureus 6 %, Pseudomonas aeruginosa 5 % and Acinetobacter baumannii 3%. Most of the analyzed organisms showed resistance, especially to the beta-lactam antibiotic;the enterobacteria strains isolated had revealed resistance to amoxicillin: 74%, to amoxicillin-clavulanic acid in 40% of cases, and to third-generation cephalosporins in 24%. In terms of resistance mechanisms, 11 % of the Enterobacteriaceae were extended-spectrum β-lactamase producers and 9 % of the specimens were identified as carbapenemase producers. Of the Staphylococcus aureus strains isolated, 75% were resistant to meticillin. The Glycopeptides and linezolid were the most active molecules on these isolated strains. 15% of Enterococcus species isolated in our laboratory were resistant to glycopeptides (vancomycin and teicoplanin).

Inuence of oxytetracycline on the structure and activity of microbial community in wheat rhizosphere soil

The microbial community composition in wheat rhizosphere was analyzed by detecting colony forming units （CFUs） in agar plates. The total CFUs in rhizosphere were 1.04×10^9/g soil with 9.0×10^8/g bacteria, 1.37×10^8/g actinomyces and 3.6×10^6/g fungi. The 10 dominant bacteria were isolated from wheat rhizosphere and were grouped into genus Bacillus according to their full length 16S rRNA gene sequences. Although belonging to the same genus, the isolated strains exhibited different sensitivities to oxytetracycline. When a series of the rhizosphere soil was exposed under various concentrations of oxytetracycline, the microbial community structure was highly affected with significant decline of CFUs of bacteria and actinomyces （22.2% and 31.7% at 10 mg/kg antibiotic, respectively）. This inhibition was clearly enhanced with the increase exposure dosage of antibiotic and could not be eliminated during 30 d incubation. There was no obvious influence of this treatment on fungi population. Among the four soil enzymes （alkaline phosphatase, acidic phosphatase, dehydrogenase and urease）, only alkaline phospbatase was sensitive to oxytetracycline exposure with 41.3% decline of the enzyme activity at 10 mg/kg antibiotic and further decrease of 64.3%-80.8% when the dosage over 30 mg/kg.

A VIBRIO ANGUILLARUM STRAIN ASSOCIATED WITH SKIN ULCER ON CULTURED FLOUNDER, PARALICHTHYS OLIVACEUS

The characteristics of a bacterium strain M3, isolated from cultured flounder Paralichthys olivaceus with remarkable external sign of skin ulcer during an epizootic outbreak, indicated that the bacterium belonged to the species Vibrio anguillarum . Challenge by I.M. (intramuscular injection), bath, and oral administration with M3 showed that it was highly pathogenic for Paralichthys olivacues . The LD 50 dose was 5.144×10 3 CFU/ per fish infection by I.M. injection. Recovered inoculated bacteria from the surviving fish revealed that the asymptomatic carriers could be a latent contagious source. Study of the effect of bacterial culture CFS (cell free supernatant) showed that the exotoxins produced by M3 play an important role in its pathogenicity for flounder. The resistance of M3 to 36 out of 41 antibiotics indicated that the bacterial disease outbreak was mainly attributable to the frequent and excessive use of antimicrobial agents; and that vaccination would be an effective precaution against bacterial disease.

Purification of a Diatom and Its Identification to Cylindrotheca closterium

A diatom was purified with colony selection and continuous dilution methods. It was identified to Cylindrotheca closterium according to its morphological characteristics and rbc L and 18 s r RNA gene sequences. The alga was not sensitive to ampicillin and neomycin, but sensitive to chloramphenicol which inhibited its growth at concentrations ranging from 50 to 150 μg m L-1. The purified alga was easy to culture and its specific growth rate was 0.207 ± 0.002(d-1). It was resistant to pollution and could be harvested in an easy way. It was relatively high in lipid content(20.08% ± 0.67% of dry weight) and the combined amount of its 16:0 and 16:1(n-7), the most suitable resource of biodiesel, was as high as 64% of the total fatty acids, while the amount of polyunsaturated fatty acids reached 19.96%–20% of the total fatty acids. Thus the purified C. closterium can be cultured as a biodiesel producer or a nutrition supplement producer.

Shifting hierarchy of the conjunctival florae in the patients employed a long-time topical fluoroquinolone

AIM:To observe the shifting hierarchy of the conjunctival florae in the patients who employed a long-time topical fluoroquinolone and characterize the consequent variations of their antibiotic sensitivity and virulence.METHODS:A total of 143 eyes(143 patients)who suffered from the non-infectious corneal ulcer and topically used fluoroquinolone more than 2 wk were enrolled as the fluoroquinolone eye.The untreated fellow eye was considered as the contralateral eye.Seventy-five healthy subjects were selected as the control.The culture positivity and strains of the isolated conjunctival florae were observed.Their antibiotic susceptibility and expression of the virulence-related genes were detected.RESULTS:Florae were recovered from 84.0%,37.1%,and 57.3%of the conjunctival swabs in the control,fluoroquinolone eye,and contralateral eye,respectively.The most frequently isolated microorganisms were Staphylococcus epidermidis(34.9%)in the control,followed by Staphylococcus aureus(17.5%),Staphylococcus saprophyticus(14.3%),Micrococcus(9.5%),Propionibacterium acnes(7.9%).However,those orderly ranks shifted to Staphylococcus aureus(34.0%),Propionibacterium acnes(20.8%),Candida albicans(17.0%),Pseudomonas aeruginosa(9.4%)in the fluoroquinolone eye.A growing number of the fluoroquinolone-resistant florae survived in the fluoroquinolone eye,accompanied by an increased expression of the virulence-related genes.CONCLUSION:A long-time topical fluoroquinolone leads to a shifting hierarchy of the conjunctival florae,accompanied by the consequent variations of the antibiotic sensitivity and virulence.

Granulicatella adiacens: A Rare Cause of Infective Endocarditis: A Case Report

Granulicatella adiacens (G. adiacens), formerly classified as a nutritionally variant streptococci (NVS), is a commensal organism in the mouth. It is known to be a rare cause of infective endocarditis (IE). This case report presents a case of IE caused by G. adiacens in a 63-year-old man with mitral valve prolapse (MVP), severe mitral regurgitation (MR), and dual vessel disease (DVD). G. adiacens was isolated from two of three blood cultures, and the organism was sensitive to penicillin, vancomycin, cefotaxime, and gentamicin. He was successfully treated with a combination of ceftriaxone and gentamicin. Prompt identification of the organism and determination of antibiotic sensitivity pattern led to successful treatment. This case report showcases the challenges in diagnosis, and treatment, giving insight to healthcare providers on a rare entity.

Prevalence and resistance of Acinetobacter baumannii isolated at Hyatabad Medical Complex,Khyber Pakhtunkhwa,Pakistan

Objective:To assess the resistance against widely used antibiotics in case of Acinetobacter baumannii(A.baumannii)infection.Methods:A total of 350 samples of pus,urine,swab and others from different patients were examined and the bacterial growth appeared in 50 samples.Each sample was inoculated on blood,MacConkey and cystine lactose electrolyte deficient agar.The antimicrobial susceptibility profile of the isolates was determined using agar plate method/disk-diffusion method(modified-Kirby Baur disc diffusion method).Results:In current study,a large number of isolates of A.baumannii obtained from different specimens were resistant to avelox(56%),followed by tygacil(46%),augmentin(46%),cefspan(38%),cefixime(24%)and ampicillin(20%).However,the antibiogram of A.baumannii also showed that most of the isolates(88%)were highly sensitive to cefalexin.Second maximum sensitivity of A.baumannii was seen to amikacin(84%).The sensitivity of isolates against amikacin was followed by ticarcillin(80%).Meronem was found highly active against the tested isolates(78%).Sensitivity was observed for tienem(76%),sulzone(72%)followed by azactam(68%),cefobid(66%)to cefotaxime(66%)and ciproxin(62%).Conclusions:Results elucidate that A.baumannii is a severe problem as it has become a highly resistant species in hospitalized patients and resistant A.baumannii infection turned out to have increased all-cause mortality.