Antibiotic resistance profiling of clinical isolates of Salmonella enterica Serovar Paratyphi A in Dhaka, Bangladesh

The study was conducted to detect the antibiotic resistance profile of the clinical isolates of Salmonella enterica Serovar Paratyphi A from 100 blood samples of patients from different age groups suspected to be suffering from enteric fever. The pure cultures of the bacterial isolates were collected from some renowned diagnostic centers of Dhaka and they were further characterized through the conventional culture, microscopy and biochemical examinations. These isolates were cross checked for the antibiogram profile by the Kirby-Bauer disc diffusion method against ten different types of antibiotics. Most of the isolates were found resistant against azithromycin (100%), nalidixic acid (100%) and ceftazidime (75%). However, isolates showed sensitivity to ciprofloxacin (95%), levofloxacin (97%), cotrimoxazole (96%) and chloramphenicol (95%). These findings highlight the need for continuous monitoring of the drug resistance pattern of S. enterica Serovar Paratyphi A for better public health management. Stamford Journal of Microbiology, Vol.11 (1) 2021: 14-16

Biofilm Formation and blaOXA Genes Detection Among Acinetobacter baumannii from Clinical Isolates in a Tertiary Care Kirtipur Hospital, Nepal

(1) Background: Acinetobacter baumannii has emerged as a leading cause of nosocomial infections as they are capable of evolving resistance to various classes of antibiotics. The ability of A. baumannii to form biofilm might also be associated with increased antibiotic resistance and hence treatment failure. This study was carried to associate the biofilm formation with the drug resistance pattern of A. baumannii and to detect blaOXA-23, blaOXA-24, and blaOXA-51 from carbapenem resistance isolates. (2) Methods: Among different clinical samples, a total of 19 Acinetobacter spp. were identified with conventional microbiological procedures. The biofilm production was determined by a quantitative adherence assay. The antimicrobial susceptibility test was carried out by the Kirby-Bauer disc diffusion method, carbapenemase production detection was confirmed by Modified Hodge Test. And target resistant genes were detected by polymerase chain reaction. (3) Results: Out of 90 clinical specimens, 64.44% (58/90) showed bacterial growth. Whereas, 32.75% (19/58) isolates were identified as A. baumannii. Among all A. baumannii isolates, 84.21% (16/19) were multidrug-resistance and 63.16% (12/19) carbapenem resistance phenotypically. blaOXA-51 was detected in all the isolates and blaOXA-23 was detected only in 63.16% (12/19) isolates. However, blaOXA-24 was not detected in any of the isolates. Among A. baumannii, 89.47% (17/19) isolates produced biofilm with 47.37% (9/19) strong biofilm producers. (4) Conclusions: In the majority of MDR A. baumannii, blaOXA-51 and blaOXA-23 were detected as the determinant factor for carbapenem resistance having a direct relation with biofilm formation. This study provided a valuable clue for the management of A. baumannii infections in clinical settings.

ANTIMICROBIAL SUSCEPTIBILITY PROFILE OF PATIENTS OF UTI IN A TERTIARY CARE HOSPITAL

BACKGROUND: Urinary tract infection (UTI) is one of the commonest infection in humans, mainly following instrumentation. Common causative pathogens include E.coli, Pseudomonas, Klebsiella, Proteus etc. Thus, the aim of this study was to determine causative urinary bacteria and assess their in vitro susceptibility pattern to commonly used antimicrobial drugs. MATERIALAND METHODS: One sample from each subject was considered. Total of 100 positive urine cultures were taken. RESULT: E. coli (55%) was the predominant organism followed by K. pneumoniae (15%) and pseudomonas (11%). Resistance of microbes was high towards cefoperazone/ sulbactam, piperacillin/ tazobactam, meropenem. CONCLUSION: Findings from the study revealed that E.coli is the most predominant etiology of UTIs followed by Klebsiella. The results show that the antimicrobial resistance patterns of the causes of UTI are highly variable. The multi-drug resistance pattern in these bacteria was high. Hence, it becomes essential to treat UTI patients based on microbiological susceptibility results.

Drug-resistant Tuberculosis: First Line Drug Resistance Pattern among Mycobacterium Tuberculosis Strains Isolated from a Reference Laboratory in Kerala State, India

Resistance to antimycobacterial agents consistently remains a major obstacle to end TB in India. Geographical prevalence data regarding drug-resistant evolutionary genetics of M. tuberculosis (MTB) remains sparse in India. Our objective was to determine the genotypic drug resistance mutation pattern for Rifampicin and Isoniazid of MTB isolates to gain an understanding of the prevailing molecular epidemiology of drug-resistant tuberculosis. In this study 2528 M. tuberculosis DNA isolates from presumptive DRTB suspects received at the nodal TB reference laboratory in Kerala were tested for Rifampicin and Isoniazid resistance by sequence-based diagnostic Line Probe assay (LPA). Geographical prevalence and associations of rpoB, katG, inhA resistance codons was analyzed from January 2019 to March 2020. Among the 2528 DNA samples subjected for Rifampicin and Isoniazid resistance determination by LPA, 146 (5.8%) isolates were resistant to both drugs. Isoniazid mono-resistance was found in 164 (6.5%) and Rifampicin mono-resistance in 38 (1.5%) isolates. The most frequent rpoB mutation was S531L (60.32%) followed by S531W/L533P mutations seen in 8.15% of the isolates. S315T1 KatG mutation was seen in 97.33% of Isoniazid resistant isolates. 84.68% isolates with rpoB S531L mutation were found to be multidrug-resistant. 82.9% of isolates with rpoB S531L mutation showed katG S315T1 mutation. Mono isoniazid-resistant isolates were significantly higher compared to mono rifampicin-resistant isolates among the DNA isolates studied in our region. The molecular epidemiological pattern most frequently associated with multidrug resistance was rpoB S531L which was significantly associated with the co-presence of S315T1 mutation.

In Vitro Activity and Clinical Outcomes of Clofazimine for Nontuberculous Mycobacteria Pulmonary Disease

Limited data are available regarding the in vitro activity of clofazimine against nontuberculous mycobacteria (NTM) or on outcomes of clofazimine-containing regimens in NTM-pulmonary disease (PD). Therefore, we evaluated the in vitro activity of clofazimine and the clinical outcomes of clofazimine-containing regimens. We evaluated clofazimine in vitro activity for 303 NTM isolates from NTM-PD patients. Fifty-seven clarithromycin-resistant and 35 amikacin-resistant isolates were also analyzed. Culture conversion after a 12-month treatment regimen containing clofazimine was evaluated in 58 NTM-PD patients, including 20 patients with drug-resistant isolates. Most of the 303 isolates (238/303) had minimum inhibitory concentrations (MICs) ≤0.25 µg/mL for clofazimine (57/63 Mycobacterium avium, 53/57 M. intracellulare, 49/52 M. kansasii, 22/64 M. abscessus, and 57/67 M. massiliense). For the 57 clarithromycin-resistant and 35 amikacin-resistant isolates, most had MICs ≤0.25 µg/mL (47/57 and 32/35, respectively). Among the 38 NTM-PD patients without resistance to clarithromycin or amikacin, 47% achieved culture conversion (8/27 M. abscessus, 9/9 M. massiliense, 0/1 M. avium, and 1/1 M. intracellulare). The conversion rate was higher in the MIC ≤0.25 µg/mL group than in the MIC = 0.5 µg/mL group (13/18 vs. 5/20, p = 0.004), and an MIC ≤0.25 µg/mL remained a significant factor in multivariable analysis. Culture conversion was achieved in 20% of 20 patients with clarithromycin- or amikacin-resistant isolates. However, a clofazimine MIC ≤0.25 µg/mL was not significant for culture conversion in the 58 NTM-PD patients, regardless of the drug resistance pattern. Clofazimine was effective in vitro against NTM species. Some patients on clofazimine-containing regimens achieved culture conversion.

A Study on High and Low level Drug Resistance Pattern Among Clinical Isolates of Enterococci .

Introduction: The combined abilities of colonisation and both inherent and acquired resistance have made Enterococci a significant human pathogen. Aims and Objectives: This study was done to determine the Minimum Inhibitory Concentration of various antibiotics against Enterococci and to correlate the phenotypic and genotypic characteristics of Enterococci with low level and high level drug resistance. Materials and Methods: A total of 774 isolates of Enterococci obtained from various clinical samples were subjected to antimicrobial susceptibility testing by Kirby Bauer Disk Diffusion method. The Minimum Inhibitory Concentration of various antibiotics were determined by Vitek 2 automated system, agar dilution and E test. Results: 15 out of 774 isolates showed the presence of vancomycin resistant genes by Multiplex PCR. 10 (90.91 %) isolates out of 11 E. faecalis with van A gene showed high level resistance to Penicillin (16-64 µg/ml). 8 (72.73 %) out of 11 isolates showed high level resistance to Gentamicin (512-1024 µg/ml). 6 (54.55 %) , out of 11 isolates were resistant to β lactams. One isolate of E. faecalis from urine with van B gene showed showed high level resistance to Penicillin (32 µg/ml), Linezolid (≥ 8µg/ml), high level resistance to Gentamicin (1024 µg/ml), Fluoroquinolones (≥ 8µg/ml) and Macrolides (≥ 8µg/ml). Conclusion: Isolates of Enterococci resistant to glycopeptides, penicillin, Betalactams and aminoglycosides have important clinical implications in the treatment for infection.

Mycobacterial Lineages Associated with Drug Resistance in Patients with Extrapulmonary Tuberculosis in Addis Ababa, Ethiopia

Background. In Ethiopia, tuberculosis (TB) is one of the most common causes of illness and death. However, there is limited information available on lineages associated with drug resistance among extrapulmonary tuberculosis patients in Ethiopia. In this study, researchers looked into Mycobacterium tuberculosis lineages linked to drug resistance in patients with extrapulmonary tuberculosis in Addis Ababa, Ethiopia. Methods. On 151 Mycobacterium tuberculosis isolates, a cross-sectional analysis was performed. Spoligotyping was used to characterize mycobacterial lineages, while a phenotypic drug susceptibility test was performed to determine the drug resistance pattern. Data were analyzed using SPSS version 23. Results. Among 151 Mycobacterium tuberculosis complex (MTBC) genotyped isolates, four lineages (L1–L4), and Mycobacterium bovis were identified. The predominantly identified lineage was Euro-American (73.5%) followed by East-African-Indian (19.2%). Any drug resistance (RR) and multidrug-resistant (MDR) tuberculosis was identified among 16.2% and 7.2% of the Euro-American lineage, respectively, while it was 30.8% and 15.4% among the East-African-Indian lineages. Among all three preextensively drug-resistance (pre-XDR) cases identified, two isolates belong to T3-ETH, and the other one strain was not defined by the database. There was no statistically significant association between any type of drug resistance and either lineage or sublineages of Mycobacterium tuberculosis. Conclusion. A higher proportion of any type of drug resistance and MDR was detected among the East-African-Indian lineage compared to others. However, there was no statistically significant association between any type of drug resistance and either lineages or sublineages. Thus, the authors recommend a large-scale study.

Different microbial and resistance patterns in primary total knee arthroplasty infections – a report on 283 patients from Lithuania and Sweden

Background The microbiology and the susceptibility patterns of infected total knee arthroplasties (TKAs) vary depending on demographic, local antimicrobial stewardship, and surgical factors. We wanted to compare the recent microbial profile and antimicrobial resistance pattern in revisions due to infections after primary TKAs in Sweden and Lithuania. Our hypothesis was that there is a difference in bacteriology and resistance pattern based on patient related, societal and local hospital factors as almost similar praxis have been applied for TKA surgery, short term systemic prophylaxis and routine use of local gentamicin containing bone cement. Methods Primary TKAs revised for the first time due to verified or suspected infection were collected nationwide in Sweden during 2018, and in Lithuania between 2011 and 2020 from a single major TKA revision centre in Kaunas. We identified 202 TKAs in Sweden from the Swedish Knee Arthroplasty Register and 84 from Kaunas revised due to infection. We collected available culture reports and evaluated the type of microorganisms with antimicrobial resistance pattern at revision. Results The majority of the infected cases in Sweden were early-type prosthetic joint infection (PJI) (44%), whereas late-type PJI (52%) were more common in the Kaunas cases. Gram-positive bacteria prevailed in both Sweden (55%) and Lithuania (80%). Staphylococcus aureus was the most frequent organism identified in both countries (33% in Sweden and 34% in Lithuania). More polymicrobial infections were observed in Sweden than in Lithuania (16 and 6% respectively). Methicillin resistance in Staphylococcus aureus and coagulase-negative staphylococci were higher in Lithuania (4/28 and 19/29) than in Sweden (1/42 and 9/41). Conclusions The type of infections, microbial profile, and drug resistance pattern differed between Sweden and Lithuania. Societal and local hospitals factors with emerging resistance in Lithuania are the most plausible explanation for the difference. Lack of complete data on a national level in Lithuania underlines the importance of adding microbiology of PJIs in implant registers for national aggregation and allow cross country comparisons.

A comparative study of Bacterial culture isolates, site of infections and drug resistance pattern between COVID and non COVID patients admitted in a tertiary care hospital: A Pilot study

IntroductionSARS-CoV2 which is a corona virus also predisposes patient to secondary bacterial infection by various mechanisms like-damaging the respiratory epithelium, profoundly affecting the innate and adaptive immunity, antagonising Interferon responses that enhance bacterial adherence, colonisation and invasion to respiratory tissue. In addition, prolonged hospital stay, invasive therapeutic devices, widespread use of empiric antibiotics and most importantly use of immune-suppressants like Steroid or Tocilizumab further increases the chances of bacterial infection. As opposed to this concept-physical distancing, frequent hand washing and use of gloves and protective gear by the healthcare workers also diminishes the chance of secondary bacterial infection. The present study is done to delineate the bacteriological profile, infection site predisposition or to gain knowledge on antibiotic sensitivity pattern.MethodRetrospective data will be analyzed from June 2020, when the first COVID wave came to June 2021, corresponding to second COVID wave. The present study is a pilot study before collecting and analyzing the whole data Only those samples which were positive for bacterial isolates were randomly selected and the COVID status and drug resistance patterns were checked.Results and discussionThe most common organism found was Klebsiella. Acinetobacter was also found in few patients. But most striking finding was that COVID positive patients showed higher incidence of antibiotic resistance with Acinetobacter. Though E Coli was also found commonly in COVID positive patients, they were not drug resistant.ConclusionMDR infections are common in COVID patients. Acinetobacter and Klebsiella are prone to develope MDR infections. While E.Coli is also common in COVID patients, chance of drug resistance is less among them.