Distribution of pathogenic bacteria and antimicrobial sensitivity of eye infections in Suzhou

AIM:To investigate the types of bacteria in patients with eye infections in Suzhou and their drug resistance to commonly used antibacterial drugs.METHODS:The clinical data of 155 patients were retrospectively collected in this study,and the pathogenic bacteria species and drug resistance of each pathogenic bacteria were analyzed.RESULTS:Among the 155 patients(age from 12 to 87 years old,with an average age of 57,99 males and 56 females)with eye infections(160 eyes:74 in the left eye,76 in the right eye and 5 in both eyes,all of which were exogenous),71(45.81%)strains were gram-positive bacteria,23(14.84%)strains were gram-negative bacteria and 61(39.35%)strains were fungi.Gram-positive bacteria were highly resistant to penicillin and erythromycin(78.87%and 46.48%respectively),but least resistant to vancomycin at 0.Gram-negative bacteria were highly resistant to cefoxitin and compound sulfamethoxazole(100%and 95.65%respectively),but least resistant to meropenem at 0.Comparison of the resistance of gram-positive and gram-negative bacteria to some drugs revealed statistically significant differences(P<0.05)in the resistance of both to cefoxitin,cotrimoxazole,levofloxacin,cefuroxime,ceftriaxone and ceftazidime,and both had higher rates of resistance to gram-negative bacteria than to gram-positive bacteria.The distribution of bacterial infection strains showed that Staphylococcus epidermidis was the most common strain in the conjunctiva,cornea,aqueous humor or vitreous body and other eye parts.Besides,Fusarium and Pseudomonas aeruginosa were also among the most common strains of conjunctival and corneal infections.CONCLUSION:Gram-positive bacteria are the dominant bacteria in eye infections,followed by gram-negative bacteria and fungi.Considering the resistance of gramnegative bacteria to multiple drugs,monitoring of bacteria should be strengthened in eye bacterial infections for effective prevention and control to reduce complications caused by eye infections.

NEW ANTIMICROBIAL SENSITIVITY TESTS OF BIOFILM OF STREPTOCOCCUS MUTANS IN ARTIFICIAL MOUTH MODEL

Objective To develop a new antimicrobial sensitivity test model for oral products in vitro.Methods A biofilm artificial mouth model for antimicrobial sensitivity tests was established by modifying the LKB chromatography chamber. Using sodium fluoride and Tea polyphenol as antimicrobial agent and Streptococcus mu-tans as target, sensitivity tests were studied. Results The modeling biofilm assay resulted in a MIC of 1. 28mg/ ml for fluoride against S. mutans, which was 32 times the MIC for broth maco-dilution method. The differential resistance of bacteria bioflim to antimicrobial agent relative to planktonic cells was also demonstrated. Conclusion The biofilm artificial mouth model may be useful in oral products test.

Relationship between Mutation of IR in the mtr System of Neisseria Gonorrhoeae and Multiple Antibiotic Resistance

To study the relationship between mutation of the inverted repeat sequence （IR） in the multiple transferable resistant system （mtr） of Neisseria gonorrhoeae （NG） and its multiple antibiotic resistance, minimal inhibitory concentrations （MICs） for the clinically isolated strains were tested by agar-dilution-method. The mtr system＇s IR gene of NG was sequenced after amplification by polymerase chain reaction （PCR）. Either two susceptive or five penicillin-resistant strains had no base mutation in IR gene, while all of the 13 strains with multiple-antibiotic-resistance had a singlebase deletion （A/T）. The result suggests that a single-base deletion of the thirteen-base IR sequence in mtr system of NG might result in multiple antibiotic resistance but is not associated with single antibiotic resistance.

Molecular Identification of Streptococcus pyogenes in Isolates from Children with Pharyngitis, Gezira State, Sudan 2022

Background: Streptococcus pyogenes (Group A streptococcus) is an important Gram-positive human pathogen affected the upper respiratory tract, such as the tonsils and pharynx, and is also induces post-infection diseases such as rheumatic fever and glomerulonephritis. This study aim to isolate Streptococcus pyogenes from children with pharyngitis and to evaluate the molecular identification of S. pyogenes compared with conventional methods. Methods: A cross sectional study was conducted on total of 200 throat swab samples which were collected from children with pharyngitis referred to Wad medani Pediatric Teaching Hospital and Wad medani ENT hospital from January to November 2021. Demographic and clinical data were collected by questionnaire. Throat swabs were tested with the standard microbiological techniques to isolated Group A streptococcus (GAS). Antimicrobial susceptibility testing was performed to all GAS isolates using the Kirby Bauer disk diffusion method according to clinical laboratory standard institute (CLSI) guidelines. Additionally, PCR was used to identify Spy 1258 gene of isolated bacteria. Results: From all throat swab samples screened, 51 isolates (25.5%) were identified as GAS. Antibiotic susceptibility testing revealed that all the GAS isolates were sensitive to Penicillin and Azithromycin. Sensitivity to Erythromycin, Gentamicin, Clarithromycin, Amoxicillin and Cephalexin were 88.2%, 86.3%, 45.1%, 41.2%, 13.7%, respectively. Based on PCR identification of Spy 1258 gene the percentage of isolated bacteria was 21%. Conclusion: The rate of isolated Streptococcus pyogenes was 25.5% by conventional methods and 21% by PCR. The bacteria were sensitive to Penicillin and Azithromycin. The Spy 1258 gene was specific for detection of Streptococcus pyogenes.

The Isolation of Vibrio cholera and Other Enteric Bacteria with Molecular Characterization of Vibrio cholera during the Outbreak of Baghdad/Iraq in 2015

Vibrio cholera, causing acute watery diarrhea known as cholera disease, affects all ages and both genders. Cholera infection outbreaks in Iraq have been reported for several years. The recent cholera outbreak, emerged throughout 2015, was investigated using bacteriological laboratory tests, singleplex and multiplex PCR technique for the detection of V. cholera from stool samples. Furthermore the toxigenic potential coupled with the antibiotic susceptibility test for cholera and other bacteria were also investigated. The stool samples were collected from 5698 patients admitted to Al-Yarmouk Teaching hospital and health care centers in Baghdad/Al-Karkh, Iraq, from the 1st of August to the 30th of December 2015. The V. cholera was isolated from 194 cases (3.4% of the cases age between 21 - 50 years). In addition, other enteric infections: Salmonellosis and Shigellosis 7 and 21 respectively, protozoan parasite Giardia lamblia and Entamoeba histolytica 2 and 43 cases respectively were also reported. High percentage of V. cholera infection was detected in October (122 cases, 62.8%), compared with other enteric infections that show high percentage of diarrheal disease in September and November. The results have confirmed that the cholera outbreak was caused by V. cholera O1, biotype El Tor, and serotype Inaba. Seven virulence genes were identified ctxA, toxR, zot, ace, rfbO1, tcpA and ompW. Moreover, the cholera isolated strains were found sensitive to most antibiotic but resistant to nalidixic acid.