Survey of antibiotic resistance in Pseudomonas aeruginosa by The Tokyo Johoku Association of Pseudomonas Studies

Enumerating Antibiotic Susceptibility Patterns of Pseudomonas aeruginosa Isolated from Different Sources in Dhaka City

Background:

Pseudomonas aeruginosa is a ubiquitous free-living bacterium and is responsible for severe nosocomial infections, life-threatening infections in immune compromised persons. The bacterium, along with its natural resistance, can acquire resistance to many antibiotics by a variety of methods.

Method:

Therefore, to compare the antibiotic sensitivity pattern of Pseudomonas aeruginosa, a total of seventeen isolates of P. aeruginosa were isolated from different sources; for example environmental sources, frozen food sources, clinical sources and medical waste materials. Isolates were confirmed to be P. aeruginosa by cultural and biochemical properties.

Result:

The isolates were tested against seventeen commercially available antibiotics to observe the antibiotic susceptibility patterns. Imipenem and meropenem were the most potent antibiotics (100% sensitivity) followed by amikacin and piperacillin with maximum sensitivity. Among others, gentamicin, ciprofloxacin, levofloxacin and aztreonam were found to be fairly active. A good number of isolates were intermediately resistant to ceftriaxone. The rates of resistance to aztreonam, cefotaxime and ceftazidime were 11.76%, 82.35% and 5.88% respectively. Complete resistance was observed against penicillin, ampicillin, cefixime and cefpodoxime.

Conclusion:

It can be concluded that the clinical isolates including isolate from medical waste, were multi-drug resistant than environmental and food isolates indicating the risk of transmission of resistance to the environmental isolates of P. aeruginosa.

Medicinal potential of Morella serata (Lam.) Killick (Myricaceae) root extracts: biological and pharmacological activities

BACKGROUND

Morella serata is a South African medicinal plant used in the treatment of microbial infections and to enhance male sexual performance. There is dearth of information in scientific literature on its efficacy and safety.

METHODS

In the present study, the root extracts were investigated for the phytochemicals that may be present the antibacterial, anticandida activity using 96 wells microtitre plate method and cytotoxicity using brine shrimp (Artemia salina) lethality assay.

RESULTS

The qualitative phytochemical screening revealed the presence of tannins, saponins, flavonoids, terpenoids and steroids. All the extracts including water inhibited both Gram positive and Gram negative bacteria strains at minimum inhibitory concentrations (MIC) ranging from 0.09 - 6.25 mgmL-1. The best activity was observed in the acetone extract inhibiting all the bacteria tested at MIC range of 0.09 - 0.78 mgmL-1 except Shigella flexneri KZN that was inhibited at 1.56 mgmL-1. Similarly, all the extracts suppressed the growth of all Candida species and Trichophyton mucoides at MIC ranging from 0.13 - 3.13 mgmL-1. The cytotoxicity assay revealed potent cytotoxic potential of M. serata methanol and ethanol root extracts by displaying LC50 of 0.26 and 0.18 μgmL-1 respectively.

CONCLUSION

The results obtained from the present study indicated broad spectrum antimicrobial activity and justifies the use of the plant in the treatment of infectious diseases. Also the species could be a good natural source of antitumor compounds considering its lethality against brine shrimp nauplii.

Risk of transmission of imipenem-resistantPseudomonas aeruginosa through use of mobile bathing service

OBJECTIVES

The demand for mobile bathing service (MBS) is increasing in the Japanese society. Therefore, we assessed the risk of MBS-associated infection in MBS clients and their caregivers by examining the bacterial colonization of MBS equipment and utensils.

METHODS

Bacterial isolates collected by the stamp agar culture method were examined by disk diffusion assay for their susceptibility to the following drugs: imipenem, ciprofloxacin, amikacin, azutreonam, ceftazidim, meropenem, piperacillin, tobramycin, ofloxacin and cefoperazone. Furthermore, these isolates were subtyped bySpeI-pulsed field gel electrophoresis (SpeI-PFGE).

RESULTS

Fifty-fourP. aeruginosa isolates were recovered from different sampling sites, and of these, 26 (47.3%) were isolated from pillows. Eighteen isolates (33.3%) were imipenem (IPM) resistant. The minimum inhibitory concentrations (MICs) of 17 isolates were between 16 and 32 μg/ml, and the MIC of one isolate was greater than 32 μg/ml. TheSpeI-PFGE typing of IPM-resistant isolates revealed that 13 of the 18 isolates were closely related (F=1.0-0.87).

CONCLUSION

Our findings suggest that MBS equipment and utensils, particularly pillows, are the primary sources of bacterial contamination and transmission and that there is a risk of MBS-mediated infection among MBS clients and their caregivers.

Prevalence and antimicrobial-resistance of Pseudomonas aeruginosa in swimming pools and hot tubs

Pseudomonas aeruginosa is an important opportunistic pathogen in recreational waters and the primary cause of hot tub folliculitis and otitis externa. The aim of this surveillance study was to determine the background prevalence and antimicrobial resistance profile of P. aeruginosa in swimming pools and hot tubs. A convenience sample of 108 samples was obtained from three hot tubs and eight indoor swimming pools. Water and swab samples were processed using membrane filtration, followed by confirmation with polymerase chain reaction. Twenty-three samples (21%) were positive for P. aeruginosa, and 23 isolates underwent susceptibility testing using the microdilution method. Resistance was noted to several antibiotic agents, including amikacin (intermediate), aztreonam, ceftriaxone, gentamicin, imipenem, meropenem (intermediate), ticarcillin/clavulanic acid, tobramycin (intermediate), and trimethoprim/sulfamethoxazole. The results of this surveillance study indicate that 96% of P. aeruginosa isolates tested from swimming pools and hot tubs were multidrug resistant. These results may have important implications for cystic fibrosis patients and other immune-suppressed individuals, for whom infection with multidrug-resistant P. aeruginosa would have greater impact. Our results underlie the importance of rigorous facility maintenance, and provide prevalence data on the occurrence of antimicrobial resistant strains of this important recreational water-associated and nosocomial pathogen.

Suboptimal chlorine treatment of drinking water leads to selection of multidrug-resistant Pseudomonas aeruginosa

The present study was undertaken to investigate the spectrum of bacteria present in the River Gomti water before and after chlorination for drinking purposes. We observed that the strains of Pseudomonas aeruginosa that survived chlorination on three out of seven occasions were resistant to almost all the antibiotics tested. The chlorine-resistant bacteria had mucoid colonies and grew better at 24 degrees C. All attempts to isolate the plasmid responsible for chlorine resistance were unsuccessful. Laboratory experiments using different strains of the P. aeruginosa in distilled water showed that only the resistant strain survived chlorine treatment at a dose of < or =500 microg/L. Similar results were obtained when water collected from seven different sites on the River Gomti was treated with graded doses of chlorine. At the higher dose of chlorine, all the bacteria died in 30 min, whereas with lower doses all the bacteria survived. The present study underscores the importance of measuring water chlorine concentrations to assure they are sufficiently high to remove pathogenic bacteria from drinking water. To our knowledge, this is the first report in the literature of the selection of multidrug-resistant bacteria by suboptimal chlorine treatment of water.

Panipenem/betamipron

Panipenem is a parenteral carbapenem antibacterial agent with a broad spectrum of in vitro activity covering a wide range of Gram-negative and Gram-positive aerobic and anaerobic bacteria, including Streptococcus pneumoniae and species producing beta-lactamases. Panipenem is coadministered with betamipron to inhibit panipenem uptake into the renal tubule and prevent nephrotoxicity. In large, randomised clinical trials, panipenem/betamipron demonstrated good clinical and bacteriological efficacy (similar to that of imipenem/cilastatin) in adults with respiratory tract or urinary tract infections. Panipenem/betamipron was also effective in adults with surgical or gynaecological infections, and in paediatric patients with respiratory tract and urinary tract infections in noncomparative trials. In small trials in elderly patients reported as abstracts, panipenem/betamipron demonstrated clinical efficacy similar to intravenous piperacillin and greater than oral ofloxacin in urinary tract infections. Elderly patients with respiratory tract infections also responded to therapy. Panipenem/betamipron is well tolerated with few adverse events reported in clinical trials, most commonly elevated serum levels of hepatic transaminases and eosinophils, rash and diarrhoea.