scholarly journals Diversity of staphylococcal cassette chromosome mec structures in coagulase-negative staphylococci and relationship to drug resistance

2010 ◽  
Vol 59 (3) ◽  
pp. 323-329 ◽  
Author(s):  
Elvira Garza-González ◽  
Daniel López ◽  
Cesar Pezina ◽  
Walter Muruet ◽  
Virgilio Bocanegra-García ◽  
...  

The objective of this study was to determine the distribution of staphylococcal cassette chromosome mec (SCCmec) elements in meticillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from a tertiary-care hospital in Mexico and to examine the relationship to drug resistance. Fifty selected MR-CoNS isolates collected from catheters (n=15), blood (n=15), bone (n=9), bronchial lavage (n=2) and urine (n=2) and one isolate each from an abscess, cerebrospinal fluid, eye, pleural effusion, synovial fluid, tracheal aspirate and wound secretion were examined. Susceptibility testing was performed by the broth microdilution method. SCCmec types were determined by multiplex PCR and PFGE was carried out as described previously for Staphylococcus aureus. Among the MR-CoNS strains studied, the most frequently isolated species were Staphylococcus epidermidis (n=26) and Staphylococcus haemolyticus (n=13). Staphylococcus cohnii (n=5), Staphylococcus hominis (n=3), Staphylococcus sciuri (n=1), Staphylococcus pasteuri (n=1) and the recently described species Staphylococcus pettenkoferi (n=1) were also identified. The most frequent MR-CoNS genotype identified was SCCmec type IVa in S. epidermidis isolates, which also showed a high diversity in their PFGE patterns. A clone was found that amplified both SCCmec III and V elements in five isolates examined. The single MR S. pettenkoferi isolate harboured SCCmec type IVd and the single MR S. pasteuri isolate harboured SCCmec type I. The carriage of SCCmec type III was associated with resistance or intermediate resistance to meropenem (P <0.05). These results confirm the high prevalence of S. epidermidis SCCmec IVa and the high genetic diversity among MR-CoNS strains. As far as is known, this is the first report describing the newly identified S. pettenkoferi possessing SCCmec IVd and S. pasteuri harbouring SCCmec type I. MR-CoNS harbouring SCCmec type III were found to be more resistant to meropenem.

2021 ◽  
Vol 8 (3) ◽  
pp. 230-234
Author(s):  
Naga Sri Latha Bathala ◽  
M Sasidhar ◽  
S Kusuma Bai

CoNS are gaining importance due to increase in resistance rates to betalactam antibiotics and multi drug resistance. Although specific virulence factors are not as clearly established, it seems clear that factors such as bacterial polysaccharide components, and ability to form biofilm are involved in attachment and/or persistence of bacteria on foreign materials. Biofilms usually result in persistent infections that cannot be easily resolved with standard antibiotic treatments; therefore, the biofilm formation ability and the resistance to antimicrobial therapy can be intimately related. A prospective cross-sectional study was done on purely isolated CoNS from various clinical samples from both out patients and inpatients. All the test strains were subjected to antimicrobial susceptibility testing. The ability to produce biofilm was detected by tube adherence method. Among 193 CoNS isolates 156 were from inpatients and 37 were from out patients. Methicillin resistant was seen in 80.31%. Of the total, 40.41% showed moderate biofilm formation by tube adherence method. 23.32% of isolates did not form biofilm. All the isolates from blood samples showed moderate (20/26) and strong (6/26) biofilm formation. Among non biofilm producers 66.67% were MS CoNS isolates and 33.33% were MRCoNS. 94.59% of biofilm producers were MRCoNS and 5.41% were MSCoNS. Production of biofilm was relatively more (1.16) among CoNS isolates of IPD than OPD.  As Coagulase negative Staphylocooci are exhibiting multi drug resistance and are able to form biofilm, these organisms causing a major challenge for the physicians. Hence, such problems can be prevented by detection of biofilm producers and appropriate antibiotic doses modification. The issue of antibiotic resistance among CoNS needs to be addressed through a more rational use of existing antibiotics as well as the development of new antimicrobial agents.


2007 ◽  
Vol 56 (10) ◽  
pp. 1328-1333 ◽  
Author(s):  
Alice Beatriz Mombach Pinheiro Machado ◽  
Keli Cristine Reiter ◽  
Rodrigo Minuto Paiva ◽  
Afonso Luis Barth

Coagulase-negative staphylococci (CoNS) are now recognized as the aetiological agents of an important range of infections in humans. Most developed countries have reported an increase in CoNS infections in hospitalized patients that are resistant to meticillin and other antibiotics. Staphylococcal cassette chromosome mec (SCCmec) typing is essential for understanding the molecular epidemiology of meticillin-resistant Staphylococcus strains. SCCmec elements are currently classified into types I to VI based on the characteristics of the mec and ccr gene complexes and are further classified into subtypes according to their ‘junkyard DNA’ region. We evaluated the distribution of SCCmec types in CoNS from patients attending the Hospital de Clínicas de Porto Alegre over the period August 2004–December 2005. Among the 129 bloodstream isolates, 36 (27.9 %) harboured SCCmec type I, 4 (3.0 %) harboured SCCmec type II, 67 (52 %) harboured SCCmec type III, 1 (0.8 %) harboured SCCmec type IV and 4 (3.0 %) harboured SCCmec types I and III. Seventeen isolates were not typable. Identification of CoNS at the species level indicated that Staphylococcus epidermidis was the most common species, with 87 isolates, followed by Staphylococcus haemolyticus (15), Staphylococcus hominis (13), Staphylococcus capitis (12) and Staphylococcus sciuri (1). SCCmec type III was the most prevalent among isolates of S. epidermidis (52 %). Among these strains, 30 (23 %) harboured a modified SCCmec type III which contained an additional dcs region in comparison with regular type III. SCCmec type III was also highly prevalent (75 %) among S. capitis isolates. The predominant SCCmec type found among S. haemolyticus isolates was type I. However, all four isolates harbouring SCCmec type II belonged to S. haemolyticus. Our results indicate that SCCmec type III was the most prevalent among the CoNS. Isolates with SCCmec type III were more resistant to non-β-lactam antimicrobials than isolates harbouring SCCmec types I, II and IV, although the increase in resistance was statistically significant only for clindamycin (P=0.021), rifampicin (P=0.010) and levofloxacin (P=0.005).


2020 ◽  
Vol 12 (03) ◽  
pp. 230-232
Author(s):  
Dhruv Mamtora ◽  
Sanjith Saseedharan ◽  
Ritika Rampal ◽  
Prashant Joshi ◽  
Pallavi Bhalekar ◽  
...  

Abstract Background Blood stream infections (BSIs) due to Gram-positive pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) are associated with high mortality ranging from 10 to 60%. The current anti-MRSA agents have limitations with regards to safety and tolerability profile which limits their prolonged usage. Levonadifloxacin and its oral prodrug alalevonadifloxacin, a novel benzoquinolizine antibiotic, have recently been approved for acute bacterial skin and skin structure infections including diabetic foot infections and concurrent bacteremia in India. Methods The present study assessed the potency of levonadifloxacin, a novel benzoquinolizine antibiotic, against Gram-positive blood stream clinical isolates (n = 31) collected from January to June 2019 at a tertiary care hospital in Mumbai, India. The susceptibility of isolates to antibacterial agents was defined following the Clinical and Laboratory Standard Institute interpretive criteria (M100 E29). Results High prevalence of MRSA (62.5%), quinolone-resistant Staphylococcus aureus (QRSA) (87.5%), and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) (82.35%) were observed among bacteremic isolates. Levonadifloxacin demonstrated potent activity against MRSA, QRSA, and MR-CoNS strains with significantly lower minimum inhibitory concentration MIC50/90 values of 0.5/1 mg/L as compared with levofloxacin (8/32 mg/L) and moxifloxacin (2/8 mg/L). Conclusion Potent bactericidal activity coupled with low MICs support usage of levonadifloxacin for the management of BSIs caused by multidrug resistant Gram-positive bacteria.


Author(s):  
Ancy Justin J K ◽  
Bhuvaneshwari G ◽  
Kalyani M

Tuberculosis (TB) - one of the leading causes of adult death in the Asia-Pacific Region, is an infectious disease caused by Mycobacterium tuberculosis (MTB). TB remains a major public health issue especially in developing nations due to the lack of adequate rapid diagnostic testing facilities. Drug resistance in tuberculosis was observed nearly fifty years ago. The risk is now due to the emergence of new strains which are most resistant to the potent anti-tuberculosis drugs. The resistance to drugs in Mycobacterium tuberculosis is conferred by mutations witⱨ the genes encoding drug targets or drug converting enzymes. In suspected extra pulmonary tuberculosis cases also, fast and accurate laboratory diagnosis is of primary importance, since the techniques which are followed from past years for detecting acid-fast bacilli have many limitations. This study may also help in standardizing the technique for rapid identification of MDR TB in extra pulmonary TB patients in this Tertiary care Hospital. The current study describes the importance and use of Polymerase Chain Reaction (PCR) for the detection of Multidrug-resistant Mycobacterium species. The target genes encoding resistance to Isoniazid and Rifampicin were detected by Polymerase Cain reaction and Agarose gel electrophoresis. Among the 359 samples, 2% were resistant to botⱨ Isoniazid and Rifampicin and tⱨe prevalence of drug resistance was found to be more in adult age groups.


Author(s):  
Sulochana Manandhar ◽  
Raphael M. Zellweger ◽  
Nhukesh Maharjan ◽  
Sabina Dongol ◽  
Krishna G. Prajapati ◽  
...  

Abstract Background Multi-drug resistance (MDR) and extensive-drug resistance (XDR) associated with extended-spectrum beta-lactamases (ESBLs) and carbapenemases in Gram-negative bacteria are global public health concerns. Data on circulating antimicrobial resistance (AMR) genes in Gram-negative bacteria and their correlation with MDR and ESBL phenotypes from Nepal is scarce. Methods A retrospective study was performed investigating the distribution of ESBL and carbapenemase genes and their potential association with ESBL and MDR phenotypes in E. coli, Klebsiella spp., Enterobacter spp. and Acinetobacter spp. isolated in a major tertiary hospital in Kathmandu, Nepal, between 2012 and 2018. Results During this period, the hospital isolated 719 E. coli, 532 Klebsiella spp., 520 Enterobacter spp. and 382 Acinetobacter spp.; 1955/2153 (90.1%) of isolates were MDR and half (1080/2153) were ESBL producers. Upon PCR amplification, blaTEM (1281/1771; 72%), blaCTXM-1 (930/1771; 53%) and blaCTXM-8 (419/1771; 24%) were the most prevalent ESBL genes in the enteric bacilli. BlaOXA and blaOXA-51 were the most common blaOXA family genes in the enteric bacilli (918/1771; 25%) and Acinetobacter spp. (218/382; 57%) respectively. Sixteen percent (342/2153) of all isolates and 20% (357/1771) of enteric bacilli harboured blaNDM-1 and blaKPC carbapenemase genes respectively. Of enteric bacilli, Enterobacter spp. was the most frequently positive for blaKPC gene (201/337; 60%). The presence of each blaCTX-M and blaOXA were significantly associated with non-susceptibility to third generation cephalosporins (OR 14.7, p < 0.001 and OR 2.3, p < 0.05, respectively).The presence of each blaTEM, blaCTXM and blaOXA family genes were significantly associated with ESBL positivity (OR 2.96, p < 0.001; OR 14.2, p < 0.001 and OR 1.3, p < 0.05 respectively) and being MDR (OR 1.96, p < 0.001; OR 5.9, p < 0.001 and OR 2.3, p < 0.001 respectively). Conclusions This study documents an alarming level of AMR with high prevalence of MDR ESBL- and carbapenemase-positive ESKAPE microorganisms in our clinical setting. These data suggest a scenario where the clinical management of infected patients is increasingly difficult and requires the use of last-resort antimicrobials, which in turn is likely to intensify the magnitude of global AMR crisis.


2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Yibing Chen ◽  
Jijiang Suo ◽  
Mingmei Du ◽  
Liangan Chen ◽  
Yunxi Liu ◽  
...  

Background. Stenotrophomonas maltophilia bacteremia (SMB) is the most perilous situation as compared to other types of S. maltophilia infection. The present study aimed to investigate the clinical features, distribution, drug resistance, and predictors of survival of SMB in a tertiary-care hospital of China. Methods. SMB that occurred in a tertiary-care hospital in Beijing, China, within 9 years (2010–2018) was investigated in a retrospective study. Demographics, incidence, commodities, drug resistance, mortality, as well as antibiotics administration were summarized according to the electronic medical records. The risk factors for survival were analyzed by Chi-square test, Kaplan–Meier curve and Cox regression. Results. A total of 76 episodes of SMB were analyzed. The overall incidence of SMB fluctuated from 3.4 to 15.4 episodes per 1000 admissions over 9 years. Malignancy was the most common comorbidity. High in vitro sensitivity was observed to minocycline (96.1%), levofloxacin (81.6%), and trimethoprim-sulfamethoxazole (89.5%). Central venous catheter (CVC) (p=0.004), mechanical ventilation (MV) (p=0.006), hemodialysis (p=0.024), and septic shock (p=0.016) were significantly different between survival and death group. The 30-day mortality was 34.2% within 30 days after confirmation of blood culture. Factors such as hemodialysis (OR 0.287, 95% CI: 0.084–0.977, p=0.046), T-tube (OR 0.160, 95% CI: 0.029–0.881, p=0.035), and septic shock (OR 0.234, 95% CI: 0.076–0.719, p=0.011) were associated with survival. Conclusions. S. maltophilia is the major nosocomial blood stream infectious pathogenic bacteria. Trimethoprim-sulfamethoxazole and minocycline are optimal antibiotics for the treatment of SMB. T-tube, hemodialysis, and septic shock were the risk factors associated with survival of SMB patients.


Author(s):  
Yamuna Devi Bakthavatchalam ◽  
Abirami Shankar ◽  
Rajeshwari Muniyasamy ◽  
John Victor Peter ◽  
Zervos Marcus ◽  
...  

Abstract Objectives Levonadifloxacin (WCK 771; IV) and its prodrug alalevonadifloxacin (WCK 2349; oral) are benzoquinolizine fluoroquinolones, recently approved in India for the treatment of acute bacterial skin and skin structure infections with concurrent bacteraemia and diabetic foot infections. Ahead of its market launch, the present study aimed to assess the in vitro activity of levonadifloxacin against contemporary Staphylococcus aureus isolates collected from a large tertiary care hospital in India. Additionally, levonadifloxacin activity was tested against hVISA and Bengal Bay clone MRSA isolates. Methods Non-duplicate S. aureus (n = 793) isolates collected at Christian Medical College hospital, Vellore, India during 2013–19 were included in the study. MRSA isolates were identified using a cefoxitin disc diffusion assay. MICs of levonadifloxacin and comparator antibiotics were determined using the broth microdilution method. Mutations in QRDRs were identified for selected levofloxacin-non-susceptible isolates. MLST profiling was undertaken to detect the Bengal Bay clone. Results Among the 793 isolates, 441 (55.6%) were MRSA and 626 (78.9%) were non-susceptible to levofloxacin. Levonadifloxacin showed MIC50 and MIC90 values of 0.25 and 0.5 mg/L, respectively, for all S. aureus, which included hVISA and Bengal Bay clone MRSA. The potency of levonadifloxacin was 16 times superior compared with levofloxacin. Conclusions The present study demonstrated potent activity of levonadifloxacin against contemporary S. aureus isolates, which included MRSA isolates, hVISA isolates, Bengal Bay clone isolates and a high proportion of quinolone-non-susceptible isolates. The potent activity of levonadifloxacin observed in this study supports its clinical use for the treatment of S. aureus infections.


2018 ◽  
Vol 72 (2) ◽  
pp. 181-184
Author(s):  
Saugata Choudhury ◽  
Lee Kar Mun ◽  
Esme Ng Chu Xuan ◽  
Lee Shin Jia ◽  
Shawn Vasoo ◽  
...  

We compared the in vitro antimicrobial activities of tedizolid and linezolid on the Sensititre broth microdilution system for Gram-positive cocci isolates (n=146) from skin and skin structure infections and bloodstream infections, bronchoalveolar lavage and sputum. These pathogens included 40 methicillin-resistant Staphylococcus aureus, 38 coagulase-negative staphylococci, 20 Enterococcus faecalis and 48 beta-haemolytic Streptococcus spp. Susceptibility was simultaneously determined for 48 vanA vancomycin-resistant enterococci isolates 2013–2016 from rectal swabs (23 E. faecalis and 25 E. faecium, of which 4 were linezolid-non-susceptible). MIC90s for tedizolid were fourfold to eightfold lower than linezolid on the Sensititre and ranged from 0.12 to 0.5 µg/mL for the different pathogen groups. All isolates were susceptible to tedizolid except two vanA E. faecium strains (MICs of 1 and 2 µg/mL, respectively). Categorical and essential agreement for tedizolid were 99.48% and 92%, respectively, between Liofilchem gradient diffusion and Sensititre methods. Overall, the drug exhibited excellent activity against the surveyed Gram-positive pathogens.


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